Astrocytes make up almost half of the mammalian brain cells. They are called glial cells because scientists originally thought that these starlight-shaped structures serve as nerve glue.

Research suggests that these cells control the growth of axons, or the neuronal projections that carry electrical impulses.

However, scientists still considered astrocytes to be supporting actors behind neurons, which are the primary cells of the brain and nervous system.

Now, scientists at Tufts University in Massachusetts and other institutions realize that astrocytes may execute a significantly greater performance in brain activity.

Dr. Moritz Armbruster, a research assistant professor of neuroscience at Tufts, led a team of researchers in harnessing novel technology to study astrocyte-neuron exchanges.

To their surprise, the scientists observed electrical activity in astrocyte processes within mouse brain tissue. They reported: This represents a novel class of subcellular astrocyte membrane dynamics and a new form of astrocyteneuron interaction.

Dr. Armbruster and his fellow authors published their findings in Nature Neuroscience.

Using innovative tools, the Tufts team developed a technique to detect and observe electrical activity in brain cell interactions. These properties could not be seen before now.

Dr. Chris Dulla, corresponding author of the study, is an associate professor of neuroscience at the Tufts University School of Medicine and Graduate School of Biomedical Sciences. He explained that he and his colleagues []use viruses to express fluorescent proteins in the mouse brain, and thats what lets us measure this activity.

In an interview with Medical News Today, he elaborated:

[W]e had other experiments that made us think that this new type of activity must be happening in astrocytes. We just didnt have a way to show it[] So, we developed these new techniques to image the activity of the astrocytes and, using them, we showed that this thing that we thought must be happening actually was happening.

Neurotransmitters are chemical messengers that facilitate the transfer of electrical signals between neurons and support the blood-brain barrier. Scientists have long understood that astrocytes control these substances to support neuronal health.

This study breaks ground in showing that neurons release potassium ions, which change the astrocytes electrical activity. This modulation affects how the astrocytes control neurotransmitters.

Until now, scientists could not image potassium activity in the brain.

Neurons and astrocytes talk with each other in a way that has not been known about before, Dr. Dulla said.

Dr. Dulla maintains that human brain cells work the same way as mouse tissue. He said that mouse and human brain cells use the same proteins and molecules involved in brain activity.

Besides, using human tissue samples presents ethical challenges, Dr. Dulla noted: [We] have to be really careful and judicious [] with the experiments we design, and [we] dont get a chance to see [human tissue] samples like [we] can do with mice.

However, the professor shared that extensive databases give [scientists] a chance to just access human brain tissue without doing an experiment [themselves], but just getting the data that someone else has already done.

This wealth of information further demonstrates similarities between human and mouse cells and lets researchers deduce that the same processes are happening in each. The main difference is that human cells are larger and more abundant.

He also pointed out that the study highlights a bidirectional relationship between these brain cells, as astrocytes influence the neurons as well.

These findings about astrocyte-neuron interactions open a new world of questions regarding brain pathology, memory, and learning.

MNT also discussed this study with Dr. Santosh Kesari, who was not involved in this research. He is a neurologist at Providence Saint Johns Health Center in Santa Monica, CA, and regional medical director for the Research Clinical Institute of Providence Southern California.

Dr. Kesari said that this study confirms earlier research.

[T]his is one of many studies thats showing increasingly, how astrocytes and neurons interact, how they affect each other and then connecting the dots to how that affects brain function behavior, memory, seizures, dementia, and even in the context of brain tumors, all these cells interact. Dr. Santosh Kesari

Most medication development for brain disorders currently targets neurons. Dr. Kesari agreed that this study might shine light on a new path.

Maybe we should really be understanding the astrocyte side of things to develop drugs that may impact brain health by looking at that astrocytic role in brain disorders, he said.

The ability to image cell processes, as in this study, makes it possible to explore other activities within the brain as well.

The researchers are also screening existing drugs in hopes of manipulating astrocyte-neuron processes. Scientists could come close to repairing brain injuries or helping people increase their learning capacity if this proves successful.

They are also making their tools available to other labs to explore more areas of interest, such as breathing, headache, and many other neurological disorders.

See original here:
Researchers find new function performed by almost half of brain cells - Medical News Today

image:A team at Scripps Research demonstrated how protein-sugar clusters called proteoglycans can guide processes like cell maturation and neuronal synapse formation, among other functions. As one example, pictured, semi-synthetic syndecan-1 proteoglycan rescues the maturation of mouse embryonic stem cells into neural precursor cells (red and green). view more

Credit: Meg Critcher, Scripps Research

LA JOLLA, CAScientists at Scripps Research have developed a set of methods for the closer study of one of the least-accessible, least-understood players in biology: protein-sugar conjugates called proteoglycans.

These molecules are often thickly present on the surfaces of cells and are known to have a broad set of functions in the body, though how they work and how their dysfunctions contribute to diseases are largely mysteries.

The scientists, who report their work in Nature Chemical Biology on May 12, 2022, devised synthetic proteoglycans that closely mimic real ones but have convenient chemical handles for modifying them. These and other aspects of their research platform enable the systematic study of how proteoglycans structure affects their functions in health and disease. The scientists demonstrated the effectiveness of their platform by using it to make new discoveries about proteoglycans roles in early cell development and in cancer cell spreading.

Were essentially unpacking the complexity of these molecules by constructing them in a modular way ourselves, and studying them in a tightly controlled environment, says study senior author Mia Huang, PhD, associate professor in the Department of Molecular Medicine at Scripps Research.

A proteoglycan starts as just a proteinthe so-called core proteinbut this protein contains special sites where any of a variety of sugar-related molecular chains called glycosaminoglycans (GAGs) can be linked. Within the cell where the protein originates, enzymes catalyze the attachment of GAGs to it, and this newborn proteoglycan normally is further decorated with clusters of sulfur and oxygen atoms called sulfates. The finished proteoglycan may be anchored into the cell membrane, its GAG chains waving in the extracellular fluid like seagrass, or it may be secreted from the cell to perform other functions.

With such complexity, it is no surprise that proteoglycans have versatile functionsthey are present in virtually all tissues, including cartilage, collagen, bone, skin, blood vessels, brain cells and mucosal surfaces. They help steer processes such as cell maturation, cell adhesion, cell migration, and neuronal synapse formation; serve as receptors for protein signaling partners; and are even used by some viruses and bacteria to latch onto cells. But proteoglycans complexity also means that how they do what they do, and with what partners, remains largely undiscovered. Scientists arent even certain how many proteoglycans there are in human and other mammalian cellsalthough there are at least dozens.

Huang and her team, including first authors Timothy OLeary, PhD and Meg Critcher, respectively a postdoctoral researcher and doctoral candidate in the Huang Lab during the study, constructed proteoglycan core proteins that are almost identical to known core proteins, but contain special molecular handles enabling the researchers to change the numbers and locations and types of GAG chains that bind to them. This allows the researchers to study systematically how the function of a proteoglycan changes as its GAG arrangement changes.

The researchers also developed techniques allowing them to anchor their proteoglycans in cell membranes or to let them float freely, to see how this affects proteoglycans functions in different circumstances.

Using their synthetic versions of common proteoglycans called syndecans, the scientists were able to study the respective contributions of GAG chains and core proteins. Specifically, they looked at two key biological processes mediated by syndecans: the maturing of stem cells, and the spreading of breast cancer cells on an extracellular matrix.

We learned from these experiments that not only the GAG chains but also the core proteins contribute to proteoglycan function, says Critcher. Notably, we also found that proteoglycans role in cancer cell spreading depends heavily on whether they are anchored to the cell membrane or free-floating.

The team also incorporated a method called proximity tagging to help them identify proteoglycans interaction partners. Huang and colleagues are now using this, and their modular construction technique, to study the interactions of syndecans and other proteoglycans in different contextsand with different GAG arrangementsand otherwise to explore their structures and functions.

Chemical editing of proteoglycan architecture was co-authored by Timothy OLeary, Meg Critcher, Tesia Stephenson, Xueyi Yang, Abdullah Hassan, Noah Bartfield, Richard Hawkins, and Mia Huang.

Funding for the research was provided by the National Institutes of Health (R00HD090292, R35GM142462).

About Scripps Research

Scripps Research is an independent, nonprofit biomedical institute ranked the most influential in the world for its impact on innovation by Nature Index. We are advancing human health through profound discoveries that address pressing medical concerns around the globe. Our drug discovery and development division, Calibr, works hand-in-hand with scientists across disciplines to bring new medicines to patients as quickly and efficiently as possible, while teams at Scripps Research Translational Institute harness genomics, digital medicine and cutting-edge informatics to understand individual health and render more effective healthcare. Scripps Research also trains the next generation of leading scientists at our Skaggs Graduate School, consistently named among the top 10 US programs for chemistry and biological sciences. Learn more atwww.scripps.edu.

Nature Chemical Biology

Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.

Read the original here:
Sugared proteins called proteoglycans start to give up their secrets - EurekAlert

Worlds 1st Focused Ultrasound Cancer Immunotherapy Center LaunchedUVA Health and the Charlottesville-based Focused Ultrasound Center today announced the launch of theFocused Ultrasound Cancer Immunotherapy Center, the worlds first center dedicated specifically to advancing a focused ultrasound and cancer immunotherapy treatment approach that could revolutionize 21st-century cancer care.

A Study by the Gwangju Institute of Science and Technology Investigates Mercury Contamination in Freshwater Lakes in KoreaDuring the 1950s and 1960s, Minamata Bay in Japan was the site of widespread mercury poisoning caused by the consumption of fish containing methylmercurya toxic form of mercury that is synthesized when bacteria react with mercury released in water.

Researchers identify possible new target to treat newborns suffering from lack of oxygen or blood flow in the brainThe condition, known as hypoxic-ischemic encephalopathy (HIE), can result in severe brain damage, which is why researchers at theCase Western Reserve University School of Medicineand UH Rainbow Babies & Childrens Hospital (UH Rainbow) are studying the condition to evaluate how HIE is treated and develop new, more effective options.

Should You Give Your Child Opioids for Post-Operative Pain Management?Routine head and neck procedures, such as removal of tonsils and adenoids and the placement of ear tubes, may cause moderate to severe pain in pediatric patients.

Two birds with one stone: a refined bioinformatic analysis can estimate gene copy-number variations from epigenetic dataA team led by Dr. Manel Esteller, Director of the Josep Carreras Leukaemia Research Institute, has improved the computational identification of potentially druggable gene amplifications in tumors, from epigenetic data.

Some Shunts Used After Epilepsy Surgery May Risk Chronic HeadachesSurgeons who observe persistent fluid buildup after disconnecting epileptic and healthy brain areas should think twice before installing low-pressure nonprogrammable drainage shunts, according to a study coauthored by Rutgers pediatric and epilepsy neurosurgeonYasunori Nagahamathat found chronic headaches could result from these procedures.

Re-defining the selection of surgical procedure in sufferers with tuberous sclerosis complicatedBy illustrating a number of instances of tuberous sclerosis in sufferers whove undergone surgical resection with seizure-free outcomes, researchers have recognized components that decide choice of sufferers for profitable surgical procedure.

Scientists study links between obesity, age and body chemistryA team of Clemson University scientists is making inroads in understanding the relationship between certain enzymes that are normally produced in the body and their role in regulating obesity and controlling liver diseases.

Clemson scientists discover new tools to fight potentially deadly protozoa that has pregnant women avoiding cat litter boxesNow, a group of researchers from Clemson University have discovered a promising therapy for those who suffer from toxoplasmosis, a disease caused by the microscopic protozoa Toxoplasma gondii.

Rising income inequality linked to Americans declining healthRising levels of income inequality in the United States may be one reason that the health of Americans has been declining in recent decades, new research suggests.

New research to understand how the brain handles optical illusions and makes predictionsNew research projects are underway at the Allen Institute to address these questions through OpenScope, the shared neuroscience observatory that allows scientists around the world to propose and direct experiments conducted on one of the Institutes high-throughput experimental platforms.

Robotic therapy: A new effective treatment for chronic stroke rehabilitationA study led by Dr. Takashi Takebayashi and published in the journal Stroke suggests continuing therapy for chronic stroke patients is still beneficial while suggesting a radical alternative.

Children with history of maltreatment could undergo an early maturation of the immune systemThe acute psychosocial stress states stimulate the secretion of an antibody type protein which is decisive in the first immune defence against infection, but only after puberty.

Toxoplasmosis: propagation of parasite in host cell stoppedA new method blocks the protein regulation of the parasite Toxoplasma gondii and causes it to die off inside the host cell.

Research shows the role empathy may play in musicCan people who understand the emotions of others better interpret emotions conveyed through music? A new study by an international team of researchers suggests the abilities are linked.

Effects of stress on adolescent brains triple networkA new studyinBiological Psychiatry: Cognitive Neuroscience and Neuroimaging, published by Elsevier, has used functional magnetic resonance imaging (fMRI) to examine the effects of acute stress and polyvicitimization, or repeated traumas, on three brain networks in adolescents.

Reform to Mental Health Act must prompt change in support for familiesFamily members of people with severe mental health challenges need greater support to navigate the UKs care system following changes announced in yesterdays Queens Speech, say the authors of a new study published in theBritish Journal of Social Work.

New knowledge about airborne virus particles could help hospitalsMeasurements taken by researchers at Lund University in Sweden of airborne virus in hospitals provide new knowledge about how best to adapt healthcare to reduce the risk of spread of infection.

Guidance developed for rare dancing eyes syndromeExperts from Evelina London Childrens Hospital developed the guidance in collaboration with a worldwide panel of experts and families of children with the condition.

Genetic study identifies migraine causes and promising therapeutic targetsQUT genetic researchers have found blood proteins that cause migraine and have a shared link with Alzheimers disease that could potentially be prevented by repurposing existing therapeutics.

How do genomes evolve between species? The key role of 3D structure in male germ cellsA study led by scientists at the UAB and University of Kent uncovers how the genome three-dimensional structure of male germ cells determines how genomes evolve over time.

Novel Supramolecular CRISPRCas9 Carrier Enables More Efficient Genome EditingRecently, a research team from Kumamoto University, Japan, have constructed a highly flexible CRISPR-Cas9 carrier using aminated polyrotaxane (PRX) that can not only bind with the unusual structure of Cas9 and carry it into cells, but can also protect it from intracellular degradation by endosomes.

Obesity, diabetes and high blood pressure increase mortality from COVID-19 especially among young and middle-aged peopleObesity, impaired blood glucose metabolism, and high blood pressure increase the risk of dying from COVID-19 in young and middle-aged people to a level mostly observed in people of advanced age.

Are most ORR electrocatalysts promising nanocatalytic medicines for tumor therapy?The current searches for medical catalysts mainly rely on trial-and-error protocols, due to the lack of theoretical guidance.

The combination makes the difference: New therapeutic approach against breast cancerResearchers at the University of Basel have now discovered an approach that involves a toxic combination with a second target gene in order to kill the abnormal cells.

Glatiramer acetate compatible with breastfeedingA study conducted by the neurology department of Ruhr-Universitt Bochum (RUB) at St. Josef Hospital on the drug glatiramer acetate can relieve mothers of this concern during the breastfeeding period.

A*STAR, NHCS, NUS And Novo Nordisk To Collaborate On Cardiovascular Disease ResearchThe Agency for Science, Technology and Researchs (A*STAR) Genome Institute of Singapore (GIS) and Bioinformatics Institute (BII), as well as the National Heart Centre Singapore (NHCS), National University of Singapore (NUS), and pharmaceutical company Novo Nordisk have signed an agreement to study the mechanisms underlying cardiovascular disease progressionespecially the condition called heart failure with preserved ejection fraction (HFpEF).

Taking ownership of your healthA study published this month inAge and Ageing by The Japan Collaborate Cohort (JACC) Study group at Osaka University assessed the impact of modifying lifestyle behaviors on life expectancy from middle age onwards.

Experimental evolution illustrates gene bypass process for mitosisResearchers from Nagoya University demonstrated gene bypass events for mitosis using evolutionary repair experiments.

Temporomandibular Disorder-Induced Pain Likely to Worsen in Late Menopause TransitionNew study evaluates the influence of menopause symptoms on the intensity of temporomandibular disorder-induced pain throughout the full menopause transition.

Breathtaking solution for a breathless problemA drop in oxygen levels, even when temporary, can be critical to brain cells. This explains why the brain is equipped with oxygen sensors. Researchers from Japan and the United States report finding a new oxygen sensor in the mouse brain.

How calming our spinal cords could provide relief from muscle spasmsAn Edith Cowan University (ECU) studyinvestigating motoneurons in the spine has revealed two methods can make our spinal cords less excitable and could potentially be usedto treat muscle spasms.

Analysis Finds Government Websites Downplay PFAS Health RisksState and federal public health agencies often understate the scientific evidence surrounding the toxicity of per- and polyfluoroalkyl substances (PFAS) in their public communications, according toan analysispublished today in the journalEnvironmental Health.

Multiple diagnoses are the norm with mental illness; new genetic study explains whyThe study, published this weekin the journalNature Genetics, found that while there is no gene or set of genes underlying risk for all of them, subsets of disordersincluding bipolar disorder and schizophrenia; anorexia nervosa and obsessive-compulsive disorder; and major depression and anxietydo share a common genetic architecture.

Drinkers sex plus brewing method may be key to coffees link to raised cholesterolThe sex of the drinker as well as the brewing method may be key to coffees link with raised cholesterol, a known risk factor for heart disease, suggests research published in the open access journalOpen Heart.

Artificial cell membrane channels composed of DNA can be opened and locked with a keyIn new research, Arizona State University professorHao Yan, along with ASU colleagues and international collaborators from University College London describe the design and construction of artificial membrane channels, engineered using short segments of DNA.

Single cell RNA sequencing uncovers new mechanisms of heart diseaseResearchers at the Hubrecht Institute have now successfully applied a new revolutionary technology (scRNA-seq) to uncover underlying disease mechanisms, including specifically those causing the swelling.

Read this article:
Other Notable Health Studies & Research From May 11, 2022 - Study Finds

Spring has arrived in Gothenburg, and the Cline is excited to bring you some exciting news and updates from our team

The first stage of Ex-vivo testing completed

Early this month, Cline announced that the first stage of our ex-vivo experiments was carried out with encouraging performance. This newsletter will take a deeper look at what's happening in our labs and what these tests mean for StemCART.

These experiments, which began in January 2022, are an important milestone for the StemCART project and will push the project into the next development stage. In these tests, Cline has several aims; 1) demonstrate that the matrix developed by Cline successfully functions, 2) the successful differentiation of induced pluripotent stem cells (iPSCs) into functional chondrocytes (cartilage cells), and 3) to show induced healing of the injured cartilage tissue.

To achieve this, Cline has been collaborating with orthopedic surgeons and a hospital to collect cartilage tissue from patients undergoing surgery. Cline then takes this tissue from the hospital to our cell labs. At the lab we induce an artificial cartilage damage to mimic joint injuries before implanting the cells and matrix together at the injury site.

In this first stage of testing, the supporting matrix demonstrated the expected functionality in successfully fixing cells to the area of interest.

Read more about this in our latest press release or where Cline was recently featured on ORTHOWORLD.

Next steps for StemCART

The ex-vivo tests continues and Cline will carry out at least 24 further experiments in several stages. The results from these will be communicated after the completion of each stage. The upcoming stage of 10 experiments will test a higher cell concentration and focus on determining the functionality of the chondrocytes. Testing will also be expanded to include tissue of different cartilage origin, such as knee, shoulder, and hip.

StemCART's ultimate vision is as a cell-based Advanced Therapy Medical Product (ATMP) that will revolutionize the treatment of cartilage damage by providing patients with new functional cartilage and curing the condition, thus eliminating pain. StemCART provides several advantages over other therapy strategies such as autologous chondrocytes implantation and mesenchymal stem cells (MSCs) in that it provides reparative cartilage to the joint, and that an allogeneic cell source has much better scalability.

As part of the journey to this goal, Cline will continue preparing for in-human clinical trials, including scaling up production in a GMP facility together with partners, developing QA/QC methods, as well as the necessary safety testing and documentation for a clinical trial application. Cline has begun this work by evaluating different development and manufacturing options and engaging in regulatory pathway strategic planning activities.

Cline envisions out-licensing StemCART to a commercial partner following successful phase I trials. The process to identify and engage potential partners is ongoing, with the aim of generating interest in the commercialization of StemCART.

Exciting industry news and developments

2022 has already been an exciting year in the world of stem cell-based therapy and cartilage repair, showing the increasing interest and potential paradigm shift towards cell-based treatment. For example in the MSC segment, the Lund-based company Xintela recently began its first-in-human clinical trial for mesenchymal stem cells (MSC) in knee osteoarthritis (OA). Similarly, Cynata Therapeutics, working with iPSC-derived MSCs to treat knee OA, together with Fujifilm Cellular Dynamics, is currently conducting a large phase III trial. For more insights into the current landscape of cartilage repair treatments and current status of new cell-based treatments, you can read Cline Scientific's latest publication, "Insights into the present and future of cartilage regeneration and joint repair," available at https://www.mdpi.com/journal/ijms/special_issues/Cartilage_Repair.

Another leap forward for iPSC-derived tissue therapy is the conclusion of a world-first clinical trial, showing that implanting iPSC-derived corneal tissue into four nearly blind patients was safe and effective. The team from Osaka University used iPS cells to create the cornea tissue, which caused improvement of symptoms and eyesight and did not lead to any rejection or tumorigenicity.

Finally, in related orthopedic industry news, Bioventus acquired its partner CartiHeal for up to 450M USD. CartiHeal is an orthopedic device company that has developed the cartilage repair implant Agili-C, which was recently approved by the FDA. Agili-C is a cell-free scaffold implant for cartilage and osteochondral defects caused by either osteoarthritis or trauma.

We look forward to continuing to share Cline's journey in future newsletters!

Warmest regards,

The Cline Team

Click hereto subscribe to future newsletters and press releases.https://news.cision.com/cline/SubscriptionRegistrationDialog

Cline Scientific AB (publ) Telefon: 031-387 55 55Argongatan 2 C E-post: info@clinescientific.com431 53 MLNDAL Hemsida: http://www.clinescientific.com

About Cline ScientificCline Scientific develops advanced cancer diagnostics and regenerative medicine treatments. The company is working heavily with R&D through joint collaborations with pharmaceutical companies and academic researchers around the world. The focus is on projects in the cancer diagnostic and stem cell therapy fields since Clines nanotechnology here provides unmet solutions to critical challenges and functions. The unique patented surface nanotechnology is used in cell-based products and processes to drive projects within Life Science into and through the clinical phase.

https://news.cision.com/cline/r/newsletter-april-2022---progress-in-cline-s-cell-lab-and-in-the-stem-cell-therapy-field,c3555837

https://mb.cision.com/Main/12114/3555837/1571081.pdf

(c) 2022 Cision. All rights reserved., source Press Releases - English

See original here:
Newsletter April 2022 - Progress in Cline's cell lab and in the stem cell therapy field - Marketscreener.com

Stem Cell Investig. 2019; 6: 19.

1Stem Cell Research Center, Tabriz University of Medical Sciences, Tabriz, Iran;

2Department of Clinical Sciences, Faculty of Veterinary Medicine, University of Tabriz, Tabriz, Iran;

2Department of Clinical Sciences, Faculty of Veterinary Medicine, University of Tabriz, Tabriz, Iran;

3Hematology and Oncology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran

1Stem Cell Research Center, Tabriz University of Medical Sciences, Tabriz, Iran;

2Department of Clinical Sciences, Faculty of Veterinary Medicine, University of Tabriz, Tabriz, Iran;

3Hematology and Oncology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran

Contributions: (I) Conception and design: E Fathi, R Farahzadi; (II) Administrative support: E Fathi, R Farahzadi; (III) Provision of study materials or patients: None; (IV) Collection and assembly of data: R Farahzadi, N Rajabzadeh; (V) Data analysis and interpretation: All authors; (VI) Manuscript writing: All authors; (VII) Final approval of manuscript: All authors.

#These authors contributed equally to this work.

Received 2018 Nov 11; Accepted 2019 Mar 17.

Recent developments in the stem cell biology provided new hopes in treatment of diseases and disorders that yet cannot be treated. Stem cells have the potential to differentiate into various cell types in the body during age. These provide new cells for the body as it grows, and replace specialized cells that are damaged. Since mesenchymal stem cells (MSCs) can be easily harvested from the adipose tissue and can also be cultured and expanded in vitro they have become a good target for tissue regeneration. These cells have been widespread used for cell transplantation in animals and also for clinical trials in humans. The purpose of this review is to provide a summary of our current knowledge regarding the important and types of isolated stem cells from different sources of animal models such as horse, pig, goat, dog, rabbit, cat, rat, mice etc. In this regard, due to the widespread use and lot of attention of MSCs, in this review, we will elaborate on use of MSCs in veterinary medicine as well as in regenerative medicine. Based on the studies in this field, MSCs found wide application in treatment of diseases, such as heart failure, wound healing, tooth regeneration etc.

Keywords: Mesenchymal stem cells (MSCs), animal model, cell-based therapy, regenerative medicine

Stem cells are one of the main cells of the human body that have ability to grow more than 200 types of body cells (1). Stem cells, as non-specialized cells, can be transformed into highly specialized cells in the body (2). In the other words, Stem cells are undifferentiated cells with self-renewal potential, differentiation into several types of cells and excessive proliferation (3). In the past, it was believed that stem cells can only differentiate into mature cells of the same organ. Today, there are many evidences to show that stem cells can differentiate into the other types of cell as well as ectoderm, mesoderm and endoderm. The numbers of stem cells are different in the tissues such as bone marrow, liver, heart, kidney, and etc. (3,4). Over the past 20 years, much attention has been paid to stem cell biology. Therefore, there was a profound increase in the understanding of its characteristics and the therapeutic potential for its application (5). Today, the utilization of these cells in experimental research and cell therapy represents in such disorders including hematological, skin regeneration and heart disease in both human and veterinary medicine (6).The history of stem cells dates back to the 1960s, when Friedenstein and colleagues isolated, cultured and differentiated to osteogenic cell lineage of bone marrow-derived cells from guinea pigs (7). This project created a new perspective on stem cell research. In the following, other researchers discovered that the bone marrow contains fibroblast-like cells with congenic potential in vitro, which were capable of forming colonies (CFU-F) (8). For over 60 years, transplantation of hematopoietic stem cells (HSCs) has been the major curative therapy for several genetic and hematological disorders (9). Almost in 1963, Till and McCulloch described a single progenitor cell type in the bone marrow which expand clonally and give rise to all lineages of hematopoietic cells. This research represented the first characterization of the HSCs (10). Also, the identification of mouse embryonic stem cells (ESCs) in 1981 revolutionized the study of developmental biology, and mice are now used extensively as one of the best option to study stem cell biology in mammals (11). Nevertheless, their application a model, have limitations in the regenerative medicine. But this model, relatively inexpensive and can be easily manipulated genetically (12). Failure to obtain a satisfactory result in the selection of many mouse models, to recapitulate particular human disease phenotypes, has forced researchers to investigate other animal species to be more probably predictive of humans (13). For this purpose, to study the genetic diseases, the pig has been currently determined as one the best option of a large animal model (14).

Stem cells, based on their differentiation ability, are classified into different cell types, including totipotent, pluripotent, multipotent, or unipotent. Also, another classification of these cells are based on the evolutionary stages, including embryonic, fetal, infant or umbilical cord blood and adult stem cells (15). shows an overview of stem cells classifications based on differentiation potency.

An overview of the stem cell classification. Totipotency: after fertilization, embryonic stem cells (ESCs) maintain the ability to form all three germ layers as well as extra-embryonic tissues or placental cells and are termed as totipotent. Pluripotency: these more specialized cells of the blastocyst stage maintain the ability to self-renew and differentiate into the three germ layers and down many lineages but do not form extra-embryonic tissues or placental cells. Multipotency: adult or somatic stem cells are undifferentiated cells found in postnatal tissues. These specialized cells are considered to be multipotent; with very limited ability to self-renew and are committed to lineage species.

Toti-potent cells have the potential for development to any type of cell found in the organism. In the other hand, the capacity of these cells to develop into the three primary germ cell layers of the embryo and into extra-embryonic tissues such as the placenta is remarkable (15).

The pluripotent stem cells are kind of stem cells with the potential for development to approximately all cell types. These cells contain ESCs and cells that are isolated from the mesoderm, endoderm and ectoderm germ layers that are organized in the beginning period of ESC differentiation (15).

The multipotent stem cells have less proliferative potential than the previous two groups and have ability to produce a variety of cells which limited to a germinal layer [such as mesenchymal stem cells (MSCs)] or just a specific cell line (such as HSCs). Adult stem cells are also often in this group. In the word, these cells have the ability to differentiate into a closely related family of cells (15).

Despite the increasing interest in totipotent and pluripotent stem cells, unipotent stem cells have not received the most attention in research. A unipotent stem cell is a cell that can create cells with only one lineage differentiation. Muscle stem cells are one of the example of this type of cell (15). The word uni is derivative from the Latin word unus meaning one. In adult tissues in comparison with other types of stem cells, these cells have the lowest differentiation potential. The unipotent stem cells could create one cell type, in the other word, these cells do not have the self-renewal property. Furthermore, despite their limited differentiation potential, these cells are still candidates for treatment of various diseases (16).

ESCs are self-renewing cells that derived from the inner cell mass of a blastocyst and give rise to all cells during human development. It is mentioned that these cells, including human embryonic cells, could be used as suitable, promising source for cell transplantation and regenerative medicine because of their unique ability to give rise to all somatic cell lineages (17). In the other words, ESCs, pluripotent cells that can differentiate to form the specialized of the various cell types of the body (18). Also, ESCs capture the imagination because they are immortal and have an almost unlimited developmental potential. Due to the ethical limitation on embryo sampling and culture, these cells are used less in research (19).

HSCs are multipotent cells that give rise to blood cells through the process of hematopoiesis (20). These cells reside in the bone marrow and replenish all adult hematopoietic lineages throughout the lifetime of the human and animal (21). Also, these cells can replenish missing or damaged components of the hematopoietic and immunologic system and can withstand freezing for many years (22).The mammalian hematopoietic system containing more than ten different mature cell types that HSCs are one of the most important members of this. The ability to self-renew and multi-potency is another specific feature of these cells (23).

Adult stem cells, as undifferentiated cells, are found in numerous tissues of the body after embryonic development. These cells multiple by cell division to regenerate damaged tissues (24). Recent studies have been shown that adult stem cells may have the ability to differentiate into cell types from various germ layers. For example, bone marrow stem cells which is derived from mesoderm, can differentiate into cell lineage derived mesoderm and endoderm such as into lung, liver, GI tract, skin, etc. (25). Another example of adult stem cells is neural stem cells (NSCs), which is derived from ectoderm and can be differentiate into another lineage such as mesoderm and endoderm (26). Therapeutic potential of adult stem cells in cell therapy and regenerative medicine has been proven (27).

For the first time in the late 1990s, CSCs were identified by John Dick in acute myeloid diseases. CSCs are cancerous cells that found within tumors or hematological cancers. Also, these cells have the characteristics of normal stem cells and can also give rise to all cell types found in a particular cancer sample (28). There is an increasing evidence supporting the CSCs hypothesis. Normal stem cells in an adult living creature are responsible for the repair and regeneration of damaged as well as aged tissues (29). Many investigations have reported that the capability of a tumor to propagate and proliferate relies on a small cellular subpopulation characterized by stem-like properties, named CSCs (30).

Embryonic connective tissue contains so-called mesenchymes, from which with very close interactions of endoderm and ectoderm all other connective and hematopoietic tissues originate, Whereas, MSCs do not differentiate into hematopoietic cell (31). In 1924, Alexander A. Maxi mow used comprehensive histological detection to identify a singular type of precursor cell within mesenchyme that develops into various types of blood cells (32). In general, MSCs are type of cells with potential of multi-lineage differentiation and self-renewal, which exist in many different kinds of tissues and organs such as adipose tissue, bone marrow, skin, peripheral blood, fallopian tube, cord blood, liver and lung et al. (4,5). Today, stem cells are used for different applications. In addition to using these cells in human therapy such as cell transplantation, cell engraftment etc. The use of stem cells in veterinary medicine has also been considered. The purpose of this review is to provide a summary of our current knowledge regarding the important and types of isolated stem cells from different sources of animal models such as horse, pig, goat, dog, rabbit, cat, rat, mice etc. In this regard, due to the widespread use and lot of attention of MSCs, in this review, we will elaborate on use of MSCs in veterinary medicine.

The isolation method, maintenance and culture condition of MSCs differs from the different tissues, these methods as well as characterization of MSCs described as (36). MSCs could be isolated from the various tissues such as adipose tissue, bone marrow, umbilical cord, amniotic fluid etc. (37).

Diagram for adipose tissue-derived mesenchymal stem cell isolation (3).

Diagram for bone marrow-derived MSCs isolation (33). MSC, mesenchymal stem cell.

Diagram for umbilical cord-derived MSCs isolation (34). MSC, mesenchymal stem cell.

Diagram for isolation of amniotic fluid stem cells (AFSCs) (35).

Diagram for MSCs characterization (35). MSC, mesenchymal stem cell.

The diversity of stem cell or MSCs sources and a wide aspect of potential applications of these cells cause to challenge for selecting an appropriate cell type for cell therapy (38). Various diseases in animals have been treated by cell-based therapy. However, there are immunity concerns regarding cell therapy using stem cells. Improving animal models and selecting suitable methods for engraftment and transplantation could help address these subjects, facilitating eventual use of stem cells in the clinic. Therefore, for this purpose, in this section of this review, we provide an overview of the current as well as previous studies for future development of animal models to facilitate the utilization of stem cells in regenerative medicine (14). Significant progress has been made in stem cells-based regenerative medicine, which enables researchers to treat those diseases which cannot be cured by conventional medicines. The unlimited self-renewal and multi-lineage differentiation potential to other types of cells causes stem cells to be frontier in regenerative medicine (24). More researches in regenerative medicine have been focused on human cells including embryonic as well as adult stem cells or maybe somatic cells. Today there are versions of embryo-derived stem cells that have been reprogrammed from adult cells under the title of pluripotent cells (39). Stem cell therapy has been developed in the last decade. Nevertheless, obstacles including unwanted side effects due to the migration of transplanted cells as well as poor cell survival have remained unresolved. In order to overcome these problems, cell therapy has been introduced using biocompatible and biodegradable biomaterials to reduce cell loss and long-term in vitro retention of stem cells.

Currently in clinical trials, these biomaterials are widely used in drug and cell-delivery systems, regenerative medicine and tissue engineering in which to prevent the long-term survival of foreign substances in the body the release of cells are controlled (40).

Today, the incidence and prevalence of heart failure in human societies is a major and increasing problem that unfortunately has a poor prognosis. For decades, MSCs have been used for cardiovascular regenerative therapy as one of the potential therapeutic agents (41). Dhein et al. [2006] found that autologous bone marrow-derived mesenchymal stem cells (BMSCs) transplantation improves cardiac function in non-ischemic cardiomyopathy in a rabbit model. In one study, Davies et al. [2010] reported that transplantation of cord blood stem cells in ovine model of heart failure, enhanced the function of heart through improvement of right ventricular mass, both systolic and diastolic right heart function (42). In another study, Nagaya et al. [2005] found that MSCs dilated cardiomyopathy (DCM), possibly by inducing angiogenesis and preventing cardial fibrosis. MSCs have a tremendous beneficial effect in cell transplantation including in differentiating cardiomyocytes, vascular endothelial cells, and providing anti-apoptotic as well angiogenic mediators (43). Roura et al. [2015] shown that umbilical cord blood mesenchymal stem cells (UCBMSCs) are envisioned as attractive therapeutic candidates against human disorders progressing with vascular deficit (44). Ammar et al., [2015] compared BMSCs with adipose tissue-derived MSCs (ADSCs). It was demonstrated that both BMSCs and ADSCs were equally effective in mitigating doxorubicin-induced cardiac dysfunction through decreasing collagen deposition and promoting angiogenesis (45).

There are many advantages of small animal models usage in cardiovascular research compared with large animal models. Small model of animals has a short life span, which allow the researchers to follow the natural history of the disease at an accelerated pace. Some advantages and disadvantages are listed in (46).

Despite of the small animal model, large animal models are suitable models for studies of human diseases. Some advantages and disadvantages of using large animal models in a study protocol planning was elaborated in (47).

Chronic wound is one of the most common problem and causes significant distress to patients (48). Among the types of tissues that stem cells derived it, dental tissuederived MSCs provide good sources of cytokines and growth factors that promote wound healing. The results of previous studies showed that stem cells derived deciduous teeth of the horse might be a novel approach for wound care and might be applied in clinical treatment of non-healing wounds (49). However, the treatment with stem cells derived deciduous teeth needs more research to understand the underlying mechanisms of effective growth factors which contribute to the wound healing processes (50). This preliminary investigation suggests that deciduous teeth-derived stem cells have the potential to promote wound healing in rabbit excisional wound models (49). In the another study, Lin et al. [2013] worked on the mouse animal model and showed that ADSCs present a potentially viable matrix for full-thickness defect wound healing (51).

Many studies have been done on dental reconstruction with MSCs. In one study, Khorsand et al. [2013] reported that dental pulp-derived stem cells (DPSCs) could promote periodontal regeneration in canine model. Also, it was shown that canine DPSCs were successfully isolated and had the rapid proliferation and multi-lineage differentiation capacity (52). Other application of dental-derived stem cells is shown in .

Diagram for application of dental stem cell in dentistry/regenerative medicine (53).

As noted above, stem cells have different therapeutic applications and self-renewal capability. These cells can also differentiate into the different cell types. There is now a great hope that stem cells can be used to treat diseases such as Alzheimer, Parkinson and other serious diseases. In stem cell-based therapy, ESCs are essentially targeted to differentiate into functional neural cells. Today, a specific category of stem cells called induced pluripotent stem (iPS) cells are being used and tested to generate functional dopamine neurons for treating Parkinson's disease of a rat animal model. In addition, NSC as well as MSCs are being used in neurodegenerative disorder therapies for Alzheimers disease, Parkinsons disease, and stroke (54). Previous studies have shown that BMSCs could reduce brain amyloid deposition and accelerate the activation of microglia in an acutely induced Alzheimers disease in mouse animal model. Lee et al. [2009] reported that BMSCs can increase the number of activated microglia, which effective therapeutic vehicle to reduce A deposits in AD patients (55). In confirmation of previous study, Liu et al. [2015] showed that transplantation of BMSCs in brain of mouse model of Alzheimers disease cause to decrease in amyloid beta deposition, increase in brain-derived neurotrophic factor (BDNF) levels and improvements in social recognition (56). In addition of BMSCs, NSCs have been proposed as tools for treating neurodegeneration disease because of their capability to create an appropriate cell types which transplanted. kerud et al. [2001] demonstrated that NSCs efficiently express high level of glial cell line-derived neurotrophic factor (GDNF) in vivo, suggesting a use of these cells in the treatment of neurodegenerative disorders, including Parkinsons disease (57). In the following, Venkataramana et al. [2010] transplanted BMSCs into the sub lateral ventricular zones of seven Parkinsons disease patients and reported encouraging results (58).

The human body is fortified with specialized cells named MSCs, which has the ability to self-renew and differentiate into various cell types including, adipocyte, osteocyte, chondrocyte, neurons etc. In addition to mentioned properties, these cells can be easily isolated, safely transplanted to injured sites and have the immune regulatory properties. Numerous in vitro and in vivo studies in animal models have successfully demonstrated the potential of MSCs for various diseases; however, the clinical outcomes are not very encouraging. Based on the studies in the field of stem cells, MSCs find wide application in treatment of diseases, such as heart failure, wound healing, tooth regeneration and etc. In addition, these cells are particularly important in the treatment of the sub-branch neurodegenerative diseases like Alzheimer and Parkinson.

The authors wish to thank staff of the Stem Cell Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.

Funding: The project described was supported by Grant Number IR.TBZMED.REC.1396.1218 from the Stem Cell Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

Conflicts of Interest: The authors have no conflicts of interest to declare.

View original post here:
Stem cell-based regenerative medicine - PMC

The new report by Expert Market Research titled, Global Stem Cell Market Report and Forecast 2022-2027, gives an in-depth analysis of the globalstem cell market, assessing the market based on its segments like types, treatment types, applications and major regions. The report tracks the latest trends in the industry and studies their impact on the overall market. It also assesses the market dynamics, covering the key demand and price indicators, along with analysing the market based on the SWOT and Porters Five Forces models.

Request a free sample copy in PDF or view the report summary@https://www.expertmarketresearch.com/reports/stem-cell-market/requestsample

The key highlights of the report include:

Market Overview (2017-2027)

The stem cell business is growing due to an increase in activities to use stem cells in regenerative treatments due to their medicinal qualities. The increasing use of human-induced pluripotent stem cells (iPSCs) for the treatment of hereditary cardiac difficulties, neurological illnesses, and genetic diseases such as recessive dystrophic epidermolysis bullosa (RBED) is driving the market forward.

Furthermore, because human-induced pluripotent stem cells (iPSCs) may reverse immunosuppression, they serve as a major source of cells for auto logic stem cell therapy, boosting the industrys expansion. Furthermore, the rising incentives provided by major businesses to deliver breakthrough stem cell therapies, as well as the increased use of modern resources and techniques in research and development activities (R&D), are propelling the stem cell market forward.

Because of increased research and development (R&D) in the United States and Canada, North America accounts for a significant portion of the overall stem cell business. Furthermore, the increased frequency of non-communicable chronic diseases such as cancer and Parkinsons disease, among others, is boosting the use of stem cell therapy, boosting the industrys growth. Furthermore, the regions stronghealthcaresector is improving access to innovative cell therapy treatments, assisting the regional stem cell industrys expansion. Aside from that, due to the rising use of regenerative treatments, the Asia Pacific area is predicted to rise rapidly. Furthermore, rising clinical trials are assisting market expansion due to low labour costs and the availability of raw materials in the region, contributing considerably to overall industry growth.

Industry Definition and Major Segments

A stem cell is a type of cell that has the ability to develop into a variety of cells, including brain cells and muscle cells. It can also help to repairtissuesthat have been injured. Because stem cells have the potential to treat a variety of non-communicable and chronic diseases, including Alzheimers and diabetes, theyre being used in medical and biotechnological research to repair tissue damage caused by diseases.

Explore the full report with the table of contents@https://www.expertmarketresearch.com/reports/stem-cell-market

The major product types of stem cell are:

The market can be broadly categorised on the basis of its treatment types into:

Based on applications, the market is divided into:

The EMR report looks into the regional markets of stem cell-like:

Market Trends

The market is expected to rise due to increased research activity in regenerative medicine and biotechnology to personalise stem cell therapy. The usage of stem cells is predicted to increase as the need for treatment of common disorders, such as age-related macular degeneration (AMD), grows among the growing geriatric population. Due to multiple error bars during research operations, it becomes extremely difficult to characterise cell products because each cell has unique properties. As a result, the integration of cutting-edge technologies such as artificial intelligence (AI), blockchain, and machine learning is accelerating. Artificial intelligence (AI) is being used to analyse images quickly, forecast cell functions, and classify tissues in order to identify cell products, which is expected to boost the market growth.

With the rising frequency of cancer and cancer-related research initiatives, blockchain technology is increasingly being used to collect and assimilate data in order to improve access to clinical outcomes and the latest advances. Blockchain can also help with data storage for patients while improving the cost-effectiveness of cord-blood banking for advanced research and development (R&D) purposes. In addition, the use of machine learning techniques to analyse photos and infer the relationship between cellular features is boosting the market growth. The increased interest in understanding cellular processes and identifying critical processes using deep learning is expected to move the stem cell business forward.

Latest News on Global Stem Cell Market@https://www.expertmarketresearch.com/pressrelease/global-stem-cell-market

Key Market Players

The major players in the market are Pluristem Therapeutics Inc., Thermo Fisher Scientific Inc., Cellular Engineering Technologies, Merck KGaA, Becton, Dickinson and Company, and STEMCELL Technologies Inc The report covers the market shares, capacities, plant turnarounds, expansions, investments and mergers and acquisitions, among other latest developments of these market players.

About Us:

Expert Market Research is a leading business intelligence firm, providing custom and syndicated market reports along with consultancy services for our clients. We serve a wide client base ranging from Fortune 1000 companies to small and medium enterprises. Our reports cover over 100 industries across established and emerging markets researched by our skilled analysts who track the latest economic, demographic, trade and market data globally.

At Expert Market Research, we tailor our approach according to our clients needs and preferences, providing them with valuable, actionable and up-to-date insights into the market, thus, helping them realize their optimum growth potential. We offer market intelligence across a range of industry verticals which include Pharmaceuticals, Food and Beverage, Technology, Retail, Chemical and Materials, Energy and Mining, Packaging and Agriculture.

Media Contact

Company Name: EMR Inc.Contact Person: Sofia Williams, Corporate Sales Specialist U.S.A.Email: sales@expertmarketresearch.comToll Free Number: +1-415-325-5166 | +44-702-402-5790Address: 30 North Gould Street, Sheridan, WY 82801, USACity: SheridanState: WyomingCountry: United StatesWebsite: https://www.expertmarketresearch.com

IntroducingProcurement ResourcesServices of EMR Inc.

*We at Expert Market Research always thrive to give you the latest information. The numbers in the article are only indicative and may be different from the actual report.

See the rest here:
Global Stem Cell Market To Be Driven By Increasing Activities To Use Stem Cells In Regenerative Medicines In The Forecast Period Of 2022-2027 ...

Newswise April 28, 2022 (BRONX, NY)CAR-T therapy, a form of immunotherapy that revs up T-cells to recognize and destroy cancer cells, has revolutionized the treatment of blood cancers, including certain leukemias, lymphomas, and most recently, multiple myeloma. However, Black and Hispanic people were largely absent from the major clinical trials that led to the U.S. Food and Drug Administration approval of CAR-T cell therapies.

In a study published today in Bone Marrow Transplantation (BMT), investigators at the National Cancer Institute-designated Montefiore Einstein Cancer Center (MECC) report that Black and Hispanic patients had outcomes and side effects following CAR-T treatment that were comparable to their white and Asian counterparts.

Representation in cancer clinical trials is vital to ensuring that treatments are safe and effective for everyone, said Mendel Goldfinger, M.D., co-corresponding author of the paper, a medical oncologist at Montefiore Health System, assistant professor of medicine at Albert Einstein College of Medicine, and member of the MECC Cancer Therapeutics Program. We couldnt have been happier to learn that our patients who identify as Black and Hispanic have the same benefits from CAR-T therapy as white patients. We can only begin to say that a cancer treatment is transformational when these therapies benefit everyone who comes to us for care.

People who identify as Black and Hispanic often have tumor biology, immune system biology, and side effects that are distinct from white people. However, very few minorities were enrolled in the major trials that led the FDA to approve CAR-T cell therapy.

Parity for Black and Hispanic PatientsThe new BMT study evaluated outcomes for 46 participants treated at Montefiore between 2015 and 2021. Seventeen of the participants were Hispanic, 9 were African American, 15 were white, and 5 were Asian.

Among Black and Hispanic patients, 58% achieved a complete response after treatment and 19% achieved a partial response. For white and Asian patients, 70% achieved a complete response and 20% had a partial response, indicating no statistical differences among racial and ethnic backgrounds. Results were similar with respect to major side effects experienced: Approximately 95% of participants in each group had mild to moderate cytokine release syndrome, a common side effect to immunotherapy in which people experience fever and other flu-like symptoms.

Diversifying Cancer Clinical TrialsOur findings demonstrate that we are able to effectively treat people from historically marginalized groups using CAR-T; our hope is that more people from a diverse range of racial and ethnic backgrounds will be included in clinical trials, said co-author Amit Verma, M.B.B.S., associate director of translational science at MECC, director of the division of hemato-oncology at Montefiore and Einstein, and professor of medicine and of developmental and molecular biology at Einstein. Ira Braunschweig, M.D., associate professor of medicine at Einstein and director of Stem Cell Transplantation and Cellular Therapy and clinical program director, Hematologic Malignancies at Montefiore, is also co-corresponding author on the study.

At Montefiore, approximately 80% of clinical trial participants are minorities, compared with the nationwide figure of only 8%.

As an academic medical center, it is not enough to make novel therapies like CAR-T available, said Susan Green-Lorenzen, R.N. M.S.N., system senior vice president of operations at Montefiore and study co-author. We need to be at the forefront of ensuring that these treatments are effective for the communities we serve this research reflects this commitment.

The study is titled Efficacy and safety of CAR-T cell therapy in minorities. In addition to Drs. Goldfinger, Verma, and Braunschweig and Ms. Green-Lorenzen, other Einstein and Montefiore authors are Astha Thakkar, M.D., Michelly Abreu, N.P., Kith Pradhan, Ph.D., R. Alejandro Sica, M.D., Aditi Shastri, M.D., Noah Kornblum, M.D., Nishi Shah, M.D., M.P.H., Ioannis Mantzaris, M.D., M.S., Kira Gritsman, M.D., Ph.D., Eric Feldman, M.D., and Richard Elkind, P.A.-C.

***

About Albert Einstein College of MedicineAlbert Einstein College of Medicineis one of the nations premier centers for research, medical education and clinical investigation. During the 2021-22 academic year, Einstein is home to 732M.D.students, 190Ph.D.students, 120 students in thecombined M.D./Ph.D. program, and approximately 250postdoctoral research fellows. The College of Medicine has more than 1,900 full-time faculty members located on the main campus and at itsclinical affiliates. In 2021, Einstein received more than $185 million in awards from the National Institutes of Health. This includes the funding of majorresearch centersat Einstein in cancer, aging, intellectual development disorders, diabetes, clinical and translational research, liver disease, and AIDS. Other areas where the College of Medicine is concentrating its efforts include developmental brain research, neuroscience, cardiac disease, and initiatives to reduce and eliminate ethnic and racial health disparities. Its partnership withMontefiore, the University Hospital and academic medical center for Einstein, advances clinical and translational research to accelerate the pace at which new discoveries become the treatments and therapies that benefit patients. For more information, please visiteinsteinmed.org, read ourblog, followus onTwitter, like us onFacebook,and view us onYouTube.

About Montefiore Health SystemMontefiore Health System is one of New Yorks premier academic health systems and is a recognized leader in providing exceptional quality and personalized, accountable caretoapproximately three million people in communities across the Bronx, Westchester and the Hudson Valley. It is comprised of 10hospitals, including the Childrens Hospital at Montefiore, Burke Rehabilitation Hospital and more than 200 outpatient ambulatory care sites. The advanced clinical and translational research at its medical school, Albert Einstein College of Medicine, directly informs patient care and improves outcomes. From the Montefiore-Einstein Centers of Excellence in cancer, cardiology and vascular care, pediatrics, and transplantation,toits preeminent school-based health program, Montefiore is a fully integrated healthcare delivery system providing coordinated, comprehensive caretopatients and their families. For more information, please visitwww.montefiore.org. Followus onTwitter and Instagram and LinkedIn, or view us onFacebookandYouTube.

Read more:
Montefiore Einstein Cancer Center Finds CAR-T Therapy Effective in Black and Hispanic Patients - Newswise

Early outcomes with the combination of JSP191, fludarabine, and low-dose total body radiation (TBI) demonstrated facilitation of full donor myeloid chimerism, clearing of minimal residual disease (MRD), and a well-tolerated safety profile in older patients with myelodysplastic syndrome/acute myeloid leukemia (MDS/AML) receiving non-myeloablative (NMA) allogenic hematopoietic cell transplantation (AHCT).

Results from the phase 1 trial (NCT04429191) presented at the 2022 Transplantation & Cellular Therapy Meetings, showed there were no infusion toxicities or serious adverse events with JSP191, and no instances of primary graft failure in first 24 patients enrolled on the trial; only 1 patient had secondary graft failure and went on to have successful retransplant. Additionally, MRD clearance was observed in 12 patients, and JSP191 pharmacokinetics were shown to be predictable.

AHCT is the only curative treatment for many patients with MDS/AML, even though there have been advancements in therapy for these patients in recent years. While transplant has proven feasible for adults well into their 70s, the optimal conditioning regimen for older adults remains unknown as more intensive regimens tend to be associated with transplant-related mortality, while less intensive nonmyeloablative regimens have resulted historically in higher rates of disease relapse and progression, Lori Muffly, MD, MS, said in her presentation.

Therefore, a conditioning regimen that results in minimal toxicity but has enhanced disease control is needed in order to improve transplantation outcomes in this population, Muffly, associate professor of medicine (blood and marrow transplantation and cellular therapy) at Stanford Healthcare, continued.

JSP191 is a humanized monoclonal antibody meant to block stem cell factor binding site on CD117, which is necessary for hematopoietic stem cell (HSC) survival and HSC interactions in the bone marrow niche. After the bone marrow niche is emptied because of JSP191 binding to CD117, healthy donor cells are able to engraft. Preclinical models showed synergy between anti-CD117 monoclonal antibodies and low-dose TBI to help deplete HSC and facilitate donor cell engraftment.

For the first 24 patients with MDS (n = 13) or AML (n = 11), primary end points evaluated were safety, tolerability, and pharmacokinetics of the combination. Secondary end points included engraftment and donor chimerism, MRD clearance, relapse-free survival, graft-vs-host disease (GVHD), non-relapse mortality, and overall survival. Patients received AHCT, then 200 to 300 cGy of TBI, 30 mg/m2 of fludarabine for 3 days, and 0.6 mg/kg of intravenous JSP191.

To determine the starting date of fludarabine, real-time pharmacokinetic measurements and modeling were used after JSP191 was administered. For the first 7 patients, TBI was increased from 200 to 300 cGy to aid lymphoablation. Tacrolimus, sirolimus, and mycohphenolate motefil were used as GVHD prophylaxis.

Consistent pharmacokinetics and predictable clearance were observed with JSP191 over the 2 weeks after administration. All patients were able to receive donor cell infusion between 9 and 15 days following administration of the antibody. Interestingly, we did see in some patients very low levels of the antibody present on the day of donor cell infusion, and this did not appear to impact donor cell engraftment, Muffly said.

Bone marrow aspirations taken at screening and between administration of the antibody and fludarabine/TBI showed JSP191 depletes hemopoietic stem and progenitor cells (HSPC). In the CD34-positive, CD45RA-negative population, there was a 66% mean depletion of HSPC. The investigators do not believe this reflects the nadir of HSPC depletion, Muffly explained, and that the depletion continues until donor stem cell infusion.

All patients experienced neutropenia followed by neutrophil engraftment between TD+15 and TD+26. Primary engraftment was seen in all patients, with only 1 patient losing myeloid chimerism early, which was associated with disease progression. T cell chimerism improved when patients went up from 200 to 300 cGy.

Using flow cytometry, cytogenetics, and next-generation sequencing, investigators were able to track MRD in patients with de novo AML (n = 8) and AML from MDS (n = 3). Of the 9 patients with AML who were MRD positive at the time of enrollment, 6 were MRD negative at the time of follow-up. Eleven of 13 patients with MDS were MRD positive at enrollment, and 8 were MRD negative at the last follow-up.

After 6 months median follow-up (range, 2-12 months), there were no reports of classical grade II-IV acute GVHD. One case of late onset grade III-IV acute gastrointestinal GVHD was reported as of the latest follow-up, but this patient had non-relapse mortality. Any instances of chronic GVHD has yet to be reported due to insufficient median follow-up time. Morphologic relapse occurred in 4 patients, 3 with AML and 1 with MDS.

The median age for these patients was 70 years (range, 62-79), with a requirement of 60 years of age or older or an AHCT-comorbidity index of 3 or more to enroll in the trial. They could not have prior AHCT and needed a human leukocyte antigenmatched related or unrelated donor. Over half of patients received only a hypomethylating agent-containing regimens.

JSP191 in combination with fludarabine and low-dose TBI is a novel conditioning platform that appears safe, well tolerated, has demonstrated on-target effects of HSPC depletion, permits full donor myeloid chimerism, and results in promising early MRD clearance, Muffly concluded.

Reference:

Muffly L, Lee CJ, Gandhi A, et al. Preliminary data from a phase 1 study of JSP191, an anti-CD117 monoclonal antibody, in combination with low dose irradiation and fludarabine conditioning is well-tolerated, facilitates chimerism and clearance of minimal residual disease in older adults with MDS/AML undergoing allogeneic HCT. Presented at: 2022 Transplantation & Cellular Therapy Meetings; Salt Lake City, UT; April 23-26, 2022. Abstract LBA4. https://bit.ly/3xRTwee

Read the rest here:
Interim Data Targeting CD117 Show Promising MRD Results and Safety in MDS/AML - Targeted Oncology

AUSTIN, Texas, April 13, 2022 /PRNewswire/ -- Direct Biologics, an innovative biotechnology company with a groundbreaking extracellular vesicle (EV) platform drug technology, announced that the U.S. Food and Drug Administration (FDA) has awarded their EV drug product ExoFlo with a Regenerative Medicine Advanced Therapy (RMAT) designation for the treatment of Acute Respiratory Distress Syndrome (ARDS) associated with COVID-19. The RMAT program is designed to expedite the approval of promising regenerative medical products in the US that demonstrate clinical evidence indicating the ability to address an unmet medical need for a serious life-threatening disease or condition. Under the RMAT designation, the FDA provides intensive guidance on drug development and post-market requirements through early and frequent interactions. Additionally, an RMAT confers eligibility for accelerated approval and priority review of biologics licensing applications (BLA).

"After intensively reviewing our preclinical data, manufacturing processes, and clinical data from our Phase II multicenter, double blinded, placebo controlled randomized clinical trial, the FDA has recognized ExoFlo as a lifesaving treatment for patients suffering from Acute Respiratory Distress Syndrome (ARDS) due to severe or critical COVID-19," said Mark Adams, Chief Executive Officer. "The additional attention, resources, and regulatory benefits provided by an RMAT designation demonstrate that the FDA views ExoFlo as a product that can significantly enhance the standard of care for the thousands still dying from ARDS every week in the US," he said.

"We are very pleased that the FDA has recognized the lifesaving potential of our platform drug technology ExoFlo. The RMAT has provided a pathway to expedite our drug development to achieve a BLA in the shortest possible time," said Joe Schmidt, President. "I am very proud of our team. Everyone has been working around the clock for years in our mission to save human lives taken by a disease that lacks treatment options, both in the US and abroad. We are grateful for the opportunity to accelerate development of ExoFlo under the RMAT designation as it leads us closer to our goal of bringing our life saving drug to patients who desperately need it."

ExoFlo is an acellular human bone marrow mesenchymal stem cell (MSC) derived extracellular vesicle (EV) product. These nanosized EVs deliver thousands of signals in the form of regulatory proteins, microRNA, and messenger RNA to cells in the body, harnessing the anti-inflammatory and regenerative properties of bone marrow MSCs without the cost, complexity and limitations of scalability associated with MSC transplantation. ExoFlo is produced using a proprietary EV platform technology by Direct Biologics, LLC.

Physicians can learn more and may request information on becoming a study site at clinicaltrials.gov. For more information on Direct Biologics and regenerative medicine, visit: https://directbiologics.com.

About Direct BiologicsDirect Biologics, LLC, is headquartered in Austin, Texas, with an R&D facility located at the University of California, and an Operations and Order Fulfillment Center located in San Antonio, Texas. Direct Biologics is a market-leading innovator and cGMP manufacturer of regenerative medical products, including a robust EV platform technology. Direct Biologics' management team holds extensive collective experience in biologics research, development, and commercialization, making the Company a leader in the evolving segment of next generation regenerative biotherapeutics. Direct Biologics has obtained and is pursuing multiple additional clinical indications for ExoFlo through the FDA's investigational new drug (IND) process. For more information visit http://www.directbiologics.com.

Photo - https://mma.prnewswire.com/media/1781269/Direct_biologics_Logo.jpg

SOURCE Direct Biologics

More:
FDA Grants Direct Biologics Regenerative Medicine Advanced Therapy (RMAT) Designation for the use of ExoFlo in COVID-19 Related ARDS USA - English -...

The addition of the innate cell engager AMF13 to preactivated and expanded natural killer (NK) cells may represent an effective treatment for pretreated patients with advanced lymphoma, according to findings from a phase 1/2 study (NCT04074746) that were presented during the 2022 AACR Annual Meeting. 1

Results showed that patients experienced a median overall response rate (ORR) of 89.5% (n = 17/19). Overall, 10 patients experienced complete responses (CRs) and 7 experienced partial responses (PRs).2

Lead author Yago Nieto, MD, PhD, a professor of medicine in the Department of Stem Cell Transplantation and Cellular Therapy at the University of Texas MD Anderson Cancer Center, in Houston, discussed the findings during a press conference during the meeting. He said the study team was pleasantly surprised by the quality of tumor responses in patients with resistant lymphomas.

This is the first clinical trial using off the shelf cord blood-derived cytokine-induced memory-likeex vivoexpanded NK cells precomplexed with the innate cell engager AMF13 construct to treat patients with CD30-positive relapsed/refractory Hodgkin lymphoma, he said. We saw very encouraging activity in this population of very heavily pretreated patients.

The current standard of care for relapsed CD30-positive lymphomas is brentuximab vedotin (Adcetris), an antibody-drug conjugate that delivers a toxic cytoskeleton destabilizing agent to cells expressing CD30. However, not all these lymphomas respond to brentuximab vedotin. When that treatment fails, those tumors then become extremely resistant to killing and patients are left with very few effective therapeutic options.

To address the problem, investigators enrolled 22 patients with relapsed or refractory CD30+ lymphoma into this single-center phase 1/2 trial, 20 of whom were diagnosed with Hodgkin lymphoma (HL). All had active progressive disease at enrollment, and none received bridging therapy. Patients were heavily pretreated, with a median of 7 (range, 1-14) prior lines of therapy. Nine underwent autologous stem cell transplantation (SCT) and 5 received allogeneic SCT.

Eligible patients had relapsed/refractory CD30-positive classical HL, B-cell non-Hodgkin lymphoma, anaplastic large-cell lymphoma, or peripheral T-cell lymphoma that was refractory or intolerant to brentuximab vedotin. They needed to have an ECOG performance status of 2 or below, and adequate renal, hepatic, pulmonary, and cardiac function.

The median age was 40 years (range, 20-75). Most patients were white (68.2%) and male 68.1%).

Patients receive 2 cycles of fludarabine/cyclophosphamide, followed by AFM13-CB NK cells at 3 dose levelsDL1 (106NK/gg), DL2 (107NK/kg), and DL3 (108NK/kg)on day 0 plus 3 weekly intravenous infusions of 200 mg AFM13, a CD30/CD16A bispecific antibody. Nineteen patients completed both planned cycles of treatment.

Nieto and colleagues isolated NK cells from cord blood, then used a mixture of cytokines to activate the cells into a memory-like state, making them more persistent and effective. They then expanded the cells in culture and complexed them with AFM13.

At a median follow-up of 11 months, progression-free survival (PFS) and overall survival (OS) rates across all 3 dose levels were 52% and 81%, respectively. Across all dose levels, 53% of patients experienced CR and 37% had PR. Eleven percent had progressive disease.

Expansion of NK cells occurred immediately after infusion and persisted for 3 weeks.

Investigators established DL3 as the recommend phase 2 dose (RP2D). All 13 (100%) patients treated at this dose level responded to therapy, including eight CRs (62%).Five of those patients were in CR after cycle 1, and 3 additional patients converted from PR to CR after cycle 2, Nieto added.

The median PFS was 67% and the median OS was 93% in the RP2D population.

Investigators did not record any cytokine release syndrome or graft vs host disease (GVHD), or neurotoxicity. Our preliminary results show an excellent tolerability profile, Nieto said.

There was no instance of infusion-related reactions (IRRs) associated with AFM13-NK cells across 40 infusions. There was 1 instance of grade 3 IRR and 4 grade 2 IRRs in 108 infusions of AFM13 alone. Investigators observed no dose limiting toxicities.

Never before in mankind have we seen this approach, really leading to pretty staggering results, Timothy Yap, MBBS, PhD, FRCP, a medical oncologist and associate director of translational research in the Institute for Personalized Cancer Therapy at the University of Texas MD Anderson Cancer Center, said. Everyone can see for themselves how impressive these results are. In addition to that, the actual tolerability profile is truly excellent with no instances of cytokine release syndrome, no neurotoxicity, no GVHD. Truly, truly impressive.

References

Read more:
Adding Bispecific Antibody to Natural Killer Cells May Be Effective in Heavily Pretreated Lymphoma - http://www.oncnursingnews.com/

The SARS-CoV-2 virus can infect specialized pacemaker cells that maintain the hearts rhythmic beat, setting off a self-destruction process within the cells, according to a preclinical study co-led by researchers at Weill Cornell Medicine, NewYork-Presbyterian and NYU Grossman School of Medicine. The findings offer a possible explanation for the heart arrhythmias that are commonly observed in patients with SARS-CoV-2 infection.

In the study, reported March 8 in Circulation Research, the researchers used an animal model as well as human stem cell-derived pacemaker cells to show that SARS-CoV-2 can readily infect pacemaker cells and trigger a process called ferroptosis, in which the cells self-destruct but also produce reactive oxygen molecules that can impact nearby cells.

This is a surprising and apparently unique vulnerability of these cellswe looked at a variety of other human cell types that can be infected by SARS-CoV-2, including even heart muscle cells, but found signs of ferroptosis only in the pacemaker cells, said study co-senior author Dr. Shuibing Chen, the Kilts Family Professor of Surgery and a professor of chemical biology in surgery and of chemical biology in biochemistry at Weill Cornell Medicine.

Arrhythmias including too-quick (tachycardia) and too-slow (bradycardia) heart rhythms have been noted among many COVID-19 patients, and multiple studies have linked these abnormal rhythms to worse COVID-19 outcomes. How SARS-CoV-2 infection could cause such arrhythmias has been unclear, though.

In the new study, the researchers, including co-senior author Dr. Benjamin tenOever of NYU Grossman School of Medicine, examined golden hamstersone of the only lab animals that reliably develops COVID-19-like signs from SARS-CoV-2 infectionand found evidence that following nasal exposure the virus can infect the cells of the natural cardiac pacemaker unit, known as the sinoatrial node.

To study SARS-CoV-2s effects on pacemaker cells in more detail and with human cells, the researchers used advanced stem cell techniques to induce human embryonic stem cells to mature into cells closely resembling sinoatrial node cells. They showed that these induced human pacemaker cells express the receptor ACE2 and other factors SARS-CoV-2 uses to get into cells and are readily infected by SARS-CoV-2. The researchers also observed large increases in inflammatory immune gene activity in the infected cells.

The teams most surprising finding, however, was that the pacemaker cells, in response to the stress of infection, showed clear signs of a cellular self-destruct process called ferroptosis, which involves accumulation of iron and the runaway production of cell-destroying reactive oxygen molecules. The scientists were able to reverse these signs in the cells using compounds that are known to bind iron and inhibit ferroptosis.

This finding suggests that some of the cardiac arrhythmias detected in COVID-19 patients could be caused by ferroptosis damage to the sinoatrial node, said co-senior author Dr. Robert Schwartz, an associate professor of medicine in the Division of Gastroenterology and Hepatology at Weill Cornell Medicine and a hepatologist at NewYork-Presbyterian/Weill Cornell Medical Center.

Although in principle COVID-19 patients could be treated with ferroptosis inhibitors specifically to protect sinoatrial node cells, antiviral drugs that block the effects of SARS-CoV-2 infection in all cell types would be preferable, the researchers said.

The researchers plan to continue to use their cell and animal models to investigate sinoatrial node damage in COVID-19and beyond.

There are other human sinoatrial arrhythmia syndromes we could model with our platform, said co-senior author Dr. Todd Evans, the Peter I. Pressman M.D. Professor of Surgery and associate dean for research at Weill Cornell Medicine. And, although physicians currently can use an artificial electronic pacemaker to replace the function of a damaged sinoatrial node, theres the potential here to use sinoatrial cells such as weve developed as an alternative, cell-based pacemaker therapy.

Many Weill Cornell Medicine physicians and scientists maintain relationships and collaborate with external organizations to foster scientific innovation and provide expert guidance. The institution makes these disclosurespublic to ensure transparency. For this information, see profiles for Dr. Todd Evans, and Dr. Robert Schwartz.

Originally posted here:
Are COVID-19-Linked Arrhythmias Caused by Viral Damage to the Heart's Pacemaker Cells? - Weill Cornell Medicine Newsroom

Cell and gene therapies are poised to have a major impact on the landscape of modern medicine, carrying the potential to treat an array of different diseases with unmet clinical need.

However, the number of approved, clinically adopted cell and gene therapies is mere compared to the amount that are currently in development. A major barrier for the translation of such therapies is the safe integration of therapeutic genes into the human genome. The insertion of therapeutic genes bears the risk of off target effects, or integration of the gene into an unintended location.

A number of different strategies have been proposed to mitigate this effect. The most recent body of work comes from a collaboration between Harvards Wyss Institute for Biologically Inspired Engineering, Harvard Medical School (HMS) and the ETH Zurich in Switzerland.

Published in Cell Report Methods, the research focused on identifying safe spots in the genome. These locations, known as genomic safe harbors (GSHs), are areas in the genome that meet the following criteria: they can be accessed easily by genome-editing strategies, are within a safe distance from genes that possess functional properties and permit expression of a therapeutic gene, only once it has landed in the harbor. A simple analogy is deciding which harbor to dock a boat there are many considerations, and these depend on the type of boat you are sailing, the weather conditions and ease of access.

The research team adopted computational strategies that enabled the identification of 2,000 predicted GSHs. From this initial identification, they successfully validated two of the sites both in vitro and in vivo using reporter proteins.

Technology Networks interviewed the studys first author, Dr. Erik Aznauryan, research fellow in the laboratory of Professor George Church at Harvard Medical School. Aznauryan dives into further detail on the history of GSH research, the methods adopted to validate the GSH sites and the potential applications of this research.

Molly Campbell (MC): Can you talk about the history of genomic safe harbor research, and how they were discovered?

Erik Aznauryan (EA): Three genomic sites were empirically identified in previous studies to support stable expression of genes of interest in human cells: AAVS1, CCR5 and hRosa26. All these examples were established without any a-priori safety assessment of the genomic loci they reside in.

Attempts have been made to identify human GSH sites that would satisfy various safety criteria, thus avoiding the disadvantages of existing sites. One approach developed by Sadelain and colleagues used lentiviral transduction of beta-globin and green fluorescence protein genes into induced pluripotent stem cells (iPSCs), followed by the assessment of the integration sites in terms of their linear distance from various coding and regulatory elements in the genome, such as cancer genes, miRNAs and ultraconserved regions.

They discovered one lentiviral integration site that satisfied all of the proposed criteria, demonstrating sustainable expression upon erythroid differentiation of iPSCs. However, global transcriptome profile alterations of cells with transgenes integrated into this site were not assessed. A similar approach by Weiss and colleagues used lentiviral integrations in Chinese hamster ovary (CHO) cells to identify sites supporting long-term protein expression for biotechnological applications (e.g., recombinant monoclonal antibody production). Although this study led to the evaluation of multiple sites for durable, high-level transgene expression in CHO cells, no extrapolation to human genomic sites was carried out.

Another study aimed at identifying GSHs through bioinformatic search of mCreI sites regions targeted by monomerized version of I-CreI homing endonuclease found and characterized in green algae as capable to make targeted staggered double-strand DNA breaks residing in loci that satisfy GSH criteria. Like previous work, several stably expressing sites were identified and proposed for synthetic biology applications in humans. However, local and global gene expression profiling following integration events in these sites have not been conducted.

All these potential GSH sites possess a shared limitation of being narrowed by lentiviral- or mCreI-based integration mechanisms. Additionally, safety assessments of some of these identified sites, as well as previously established AAVS1, CCR5 and Rosa26, were carried out by evaluating the differential gene expression of genes located solely in the vicinity of these integration sites, without observing global transcriptomic changes following integration.

A more comprehensive bioinformatic-guided and genome-wide search of GSH sites based on established criteria, followed by experimental assessment of transgene expression durability in various cell types and safety assessment using global transcriptome profiling would, thus, lead to the identification of a more reliable and clinically useful genomic region.

MC: If GSHs do not encode proteins, or RNAs with functions in gene expression, or other cellular processes what is their function in the genome?

EA: In addition to protein coding, functional RNA coding, regulatory and structural regions of the human genome, other less well understood and inactive DNA regions exist.

A large proportion of the human genome seems to have evolved in the presence of a variety of integrating viruses which, as they inserted their DNA into the eukaryotic genome over the course of million years, lead to an establishment of vast non-coding elements that we continue to carry to this day. Furthermore, partial duplications of functional human genes have resulted in the formation of inactive pseudogenes, which occupy space in the genome yet are not known to bear cellular functions.

Finally, functional roles of some non-coding portions of the human genome are not well understood yet. Our search of safe harbors was conducted using existing annotation of the human genome, and as more components of it are deciphered the identification of genomic regions safe for gene insertion will become more informed.

MC: Are you able to discuss why some regions of the genome were previously regarded as GSHs but are now recognized as non-GSHs?

EA: In the absence of other alternatives, AAVS1, CCR5 and hRosa26 sites were historically called GSHs, as they supported the expression of genes of interest in a variety of cell types and were suitable for use in a research setting.

Their caveats (mainly, location within introns of functional genes, closely surrounded by other known protein coding genes as well as oncogenes) however prevent them from being used for clinical applications. Therefore, in our paper we dont call them GSHs, and refer to our newly discovered sites as GSHs.

MC: You thoroughly scanned the genome to identify candidate loci for further study as potential GSHs. Can you discuss some of the technological methods you adopted here, and why?

EA: We used several publicly available databases to identify genomic coordinates of structural, regulatory and coding components of the human genome according to the GSH criteria we outlined in the beginning of our study (outside genes, oncogenes, lncRNAs etc.,). We used these coordinates and bioinformatic tools such as command lines bedtools to exclude these genomic elements as well as areas adjacent to them. This left us with genomic regions putative GSHs from which we could then experimentally validate by inserting reporter and therapeutic genes into them followed by transcriptomic analysis of GSH-integrated vs non-integrated cells.

MC: You narrowed down your search to test five, and then two GSHs. Can you expand on your choice of reporter gene when assessing two GSHs in cell lines?

EA: Oftentimes in research you go with what is available or what is of the most interest to the lab you are currently working in.

Our case was not an exception, and we initially (up until the T cell work) used the mRuby reporter gene as it was widely available and extensively utilized and validated in our lab at ETH Zurich back then.

When I moved to the Wyss Institute at Harvard, I began collaborating with Dr. Denitsa Milanova, who was interested in testing these sites in the context of skin gene therapy particularly the treatment of junctional epidermolysis bullosa caused by mutations in various anchor proteins connecting different layers of skin, among which is the LAMB3 gene. For this reason, we decided to express this gene in human dermal fibroblasts, together with green fluorescent protein to have a visualizable confirmation of expression. We hope we would be able to translate this study into clinics.

MC: Can you describe examples of how GSHs can be utilized in potential therapeutics?

EA: Current cell therapy approaches rely on random insertion of genes of interest into the human genome. This can be associated with potential side effects including cancerous transformation of therapeutic cells as well as eventual silencing of the inserted gene.

We hope that current cell therapies will eventually transition to therapeutic gene insertions precisely into our GSHs, which will alleviate both described concerns. Specific areas of implementation may involve safer engineering of T cells for cancer treatment: insertion of genes encoding receptors targeting tumor cells or cytokines capable of enhancing anti-tumor response.

Additionally, these sites can be used for the engineering of skin cells for therapeutic (as discussed earlier with the LAMB3 example) as well as anti-aging applications, such as expression of genes that result in youthful skin phenotype.

Finally, given the robustness of gene expression from our identified sites, they can be used for industry-scale bio-manufacturing: high-yield production of proteins of interest in human cell lines for subsequent extraction and therapeutic applications (e.g., production of clotting factors for patients with hemophilias).

MC: Are there any limitations to the research at this stage?

EA: A primary limitation to this study is the low frequency of genomic integration events using CRISPR-based knock-in tools. This means that cells in which the gene of interest successfully integrated into the GSH must be pulled out of the vastly larger population of cells without this integration.

These isolated cells would then be expanded to generate homogenous population of gene-bearing cells. Such pipeline is not ideal for a clinical setting and improvements in gene integration efficiencies are needed to help this technology easier translate into clinics.

Our lab is currently working on developing genome engineering tools which would eventually allow to integrate large genes into GSHs with high precision and efficiency.

MC: What impact might this study have on the cell and gene therapy development space?

EA: This study will hopefully lead to many researchers in the field testing our sites, validating them in other therapeutically relevant cell types and eventually using them in research as well as in clinics as more reliable, durable and safe alternatives to current viral based random gene insertion methods.

Additionally, since in our work we shared all putative GSHs identified by our computational pipeline, we hope researchers will attempt to test sites we havent validated yet by implementing the GSH evaluation pipeline that we outlined in the paper. This will lead to identification of more GSHs with perhaps even better properties for clinical translation or bio-manufacturing.

MC: What are your next steps in advancing this work?

We hope to one day translate our successful in vitro skin results and start using these GSHs in an in vivo context.

Additionally, we are looking forward to improving integration efficiencies into our GSHs, which would further support clinical transition of our sites.

Finally, we will evaluate the usability of our GSHs for large-scale production of therapeutically relevant proteins, thus ameliorating the pipeline of manufacturing of biologics.

Dr. Erik Aznauryan was speaking to Molly Campbell, Senior Science Writer for Technology Networks.

Link:
Sailing the Genome in Search of Safe Harbors - Technology Networks

REDWOOD CITY, Calif., March 21, 2022 (GLOBE NEWSWIRE) --Jasper Therapeutics, Inc. (NASDAQ: JSPR), a biotechnology company focused on hematopoietic cell transplant therapies, today announced changes to its management team, including the promotions of Jeet Mahal to the newly created position of Chief Operating Officer, and of Wendy Pang, M.D., Ph.D., to Senior Vice President of Research and Translational Medicine. Both promotions are effective as of March 21, 2022. Jasper also announced that a new position of Chief Medical Officer has been created, for which an active search is underway. Judith Shizuru, M.D. PhD, co-founder, and Scientific Advisory Board Chairwoman will lead clinical development activities on an interim basis and Kevin Heller, M.D., EVP of Research and Development, will be transitioning to a consultant role.

Based on the recent progress with JSP191, our anti-CD117 monoclonal antibody, as a targeted non-toxic conditioning agent and our mRNA hematopoietic stem cell program we have decided to advance Jaspers organizational structure with the creation of the roles of Chief Operating Officer and Chief Medical Officer and by elevating our research and translational medicine team to report directly to the CEO, said Ronald Martell, CEO of Jasper Therapeutics. We also are pleased that Dr. Shizuru will lead clinical development activities on an interim basis, a role she served during the companys founding in 2019.

These changes will allow us to advance our upcoming pivotal trial of JSP191 in AML/ MDS and execute on our pipeline opportunities with a best-in-class organization, continued Mr. Martell. We also wish to thank Dr. Heller for his help advancing JSP191 through our initial AML/MDS transplant study.

In the two plus years since we founded Jasper and received our initial funding, the company has been able to advance JSP191 in two clinical studies, develop our mRNA stem cell graft platform and publicly list on NASDAQ, said Dr. Shizuru, co-founder and member of the Board of Directors of Jasper Therapeutics. These changes will strengthen the companys ability to advance the field of hematopoietic stem cell therapies and bring cures to patients with hematologic cancers, autoimmune diseases and debilitating genetic diseases."

Mr. Mahal joined Jasper in 2019 as Chief Finance and Business Officer and has led Finance, Business Development, Marketing and Facilities/ IT since the companys inception. Prior to joining Jasper, he was Vice President, Business Development and Vice President, Strategic Marketing at Portola Pharmaceuticals, where he led the successful execution of multiple business development partnerships for Andexxa, Bevyxxaand cerdulatinib. He also played a key role in the companys equity financings, including its initial public offering and multiple royalty transactions. Earlier in his career, Mr. Mahal was Director, Business and New Product Development, at Johnson & Johnson on the Xareltodevelopment and strategic marketing team. Mr. Mahal holds a BA in Molecular and Cell Biology from U.C. Berkeley, a Masters in Molecular and Cell Biology from the Illinois Institute of Technology, a Masters in Engineering from North Carolina State University and an MBA from Duke University.

Dr. Pang joined Jasper in 2020 and has led early research and development including leading creation of the companys mRNA stem cell graft platform and playing a pivotal role in advancing JSP191 across multiple clinical studies. Previously Dr. Pang was an Instructor in the Division of Blood and Marrow Transplantation at Stanford University and the lead scientist in the preclinical drug development of an anti-CD117 antibody program. She was the lead author on the proof-of-concept studies showing that an anti-CD117 antibody therapy targets disease-initiating human hematopoietic (blood cell-forming) stem cells in myelodysplastic syndrome (MDS). She has authored numerous publications on the characterization of hematopoietic stem and progenitor cell behavior in hematopoieticdiseases, as well as hematopoietic malignancies, including MDS and acute myeloid leukemia (AML), and in hematopoietic stem cell transplantation. Dr. Pang earned her AB and BM in Biology from Harvard University and her MD and PhD in cancer biology from Stanford University.

Dr. Shizuru is a Professor of Medicine (Blood and Marrow Transplantation) and Pediatrics (Stem Cell Transplantation) at StanfordUniversity.She is the clinician-scientist co-founder of Jasper Therapeutics. Dr. Shizuru is an internationally recognized expert on the basic biology of blood stem cell transplantation and the translation of this biology to clinical protocols.Dr Shizuruis a member of the Stanford Blood and Marrow Transplantation (BMT) faculty, the Stanford Immunology Program, and the Institute for Stem Cell Biology and Regenerative Medicine. Shehas been an attending clinicianattendedon the BMT clinical service since 1997.Currently, she oversees a research laboratory focused on understanding the cellular and molecular basis of resistance to engraftment of transplantedallogeneic bone marrow blood stemcells and the way in which bone marrow grafts modify immune responses.Dr. Shizuru earned her BA from Bennington College and her MD and PhD in immunology from Stanford University

About Jasper Therapeutics

Jasper Therapeutics is a biotechnology company focused on the development of novel curative therapies based on the biology of the hematopoietic stem cell. The company is advancing two potentially groundbreaking programs. JSP191, an anti-CD117 monoclonal antibody, is in clinical development as a conditioning agent that clears hematopoietic stem cells from bone marrow in patients undergoing a hematopoietic cell transplantation. It is designed to enable safer and more effective curative allogeneic hematopoietic cell transplants and gene therapies. Jasper is also advancing JSP191 as a potential therapeutic for patients with lower risk Myelodysplastic Syndrome (MDS). Jasper Therapeutics is also advancing its preclinical mRNA hematopoietic stem cell graft platform, which is designed to overcome key limitations of allogeneic and autologous gene-edited stem cell grafts. Both innovative programs have the potential to transform the field and expand hematopoietic stem cell therapy cures to a greater number of patients with life-threatening cancers, genetic diseases and autoimmune diseases than is possible today. For more information, please visit us at jaspertherapeutics.com.

Forward-Looking Statements

Certain statements included in this press release that are not historical facts are forward-looking statements for purposes of the safe harbor provisions under the United States Private Securities Litigation Reform Act of 1995. Forward-looking statements are sometimes accompanied by words such as believe, may, will, estimate, continue, anticipate, intend, expect, should, would,plan,predict,potential,seem,seek,future,outlookandsimilarexpressionsthat predict or indicate future events or trends or that are not statements of historical matters. These forward-looking statements include, but are not limited to, statements regarding the potentialof the Companys JSP191 and mRNA engineered stem cell graft programs. Thesestatementsarebasedonvariousassumptions,whetherornotidentifiedinthispressrelease, and on the current expectations of Jasper and are not predictions of actual performance. These forward-lookingstatementsareprovidedforillustrativepurposesonlyandarenotintendedtoserve as, and must not be relied on by an investor as, a guarantee, an assurance, a prediction or a definitivestatementoffactorprobability.Actualeventsandcircumstancesaredifficultorimpossible to predict and will differ from assumptions. Many actual events and circumstances are beyond the control of Jasper. These forward-looking statements are subject to a number of risks and uncertainties, including general economic, political and business conditions; the risk that the potential product candidates that Jasper develops may not progress through clinical development or receive required regulatory approvals within expected timelines or at all; risks relating to uncertainty regarding the regulatory pathway for Jaspers product candidates; the risk that prior study results may not be replicated; the risk that clinical trials may not confirm any safety, potency or other product characteristics described or assumed in this press release; the risk that Jasper will be unable to successfully market or gain market acceptance of its product candidates; the risk that Jaspers product candidates may not be beneficialtopatientsorsuccessfullycommercialized;patientswillingnesstotrynewtherapiesand the willingness of physicians to prescribe these therapies; the effects of competition on Jaspers business; the risk that third parties on which Jasper depends for laboratory, clinical development, manufacturing and other critical services will fail to perform satisfactorily; the risk thatJaspers business, operations, clinical development plans and timelines, and supply chain could be adversely affected by the effects of health epidemics, including the ongoing COVID-19 pandemic; the risk that Jasper will be unable to obtain and maintain sufficient intellectual property protection foritsinvestigationalproductsorwillinfringetheintellectualpropertyprotectionofothers;andother risks and uncertainties indicated from time to time in Jaspers filings with the SEC. If any of these risksmaterializeorJaspersassumptionsproveincorrect,actualresultscoulddiffermateriallyfrom the results implied by these forward-looking statements. While Jasper may elect to update these forward-lookingstatementsatsomepointinthefuture,Jasperspecificallydisclaimsanyobligation to do so. These forward-looking statements should not be relied upon as representing Jaspers assessmentsofanydatesubsequenttothedateofthispressrelease.Accordingly,unduereliance should not be placed upon the forward-lookingstatements.

Contacts:

John Mullaly (investors)LifeSci Advisors617-429-3548jmullaly@lifesciadvisors.com

Jeet Mahal (investors)Jasper Therapeutics650-549-1403jmahal@jaspertherapeutics.com

See the original post here:
Jasper Therapeutics Announces Management Changes to Strengthen Leadership Team - BioSpace

Emily Whitehead:

Emily Whitehead

Warriors come in all shapes and sizes. Take for example Emily Whitehead, as fresh-faced a 16-year-old as has ever graced the planet. Her eyes nearly sparkle with intellectual curiosity and dreams for a fulfilling future. But Emily is not a typical teen. She is the first pediatric patient in the world to receive CAR T-cell therapy for relapsed/refractory acute lymphoblastic leukemia (ALL). She is a singular figure in the annals of medicine. She is a soldier on the front lines of the war on cancer. And like the shot heard round the world, her personal medical assault sparked a revolution in cancer care that continues to power forward.

It has been 10 years since the only child of Thomas and Kari Whitehead of Philipsburg, PA, received an infusion of CAR T cells at the hands of a collaborative medical team from the Children's Hospital of Philadelphia (CHOP) and the Hospital of the University of Pennsylvania. That team included, among others, luminary CAR T-cell therapy pioneer, Carl June, MD, the Richard W. Vague Professor in Immunotherapy in the Department of Pathology and Laboratory Medicine and Director of the Center for Cellular Immunotherapies at Penn's Perelman School of Medicine; as well as Stephan Grupp, MD, PhD, Professor of Pediatrics at the Perelman School of Medicine (at that time, Director of the Cancer Immunotherapy Program at CHOP) and now Section Chief for Cell Therapy and Transplant at the hospital. He had been working with June on cell therapies since 2000.

Tremendous progress has flowedgushedfrom the effort to save Emily Whitehead; many more lives have been saved around the globe since that fatefulyet nearly fatalundertaking. While all the progress that has come from this story must be our ultimate theme, it cannot be fully appreciated without knowing how it came to be.

In 2010, Emily, then 5 years old, went from a being a healthy youngster one day, to a child diagnosed with ALL. Chemotherapy typically works well in pediatric ALL patients; Emily was one of the exceptions. After 2 years of intermittent chemotherapy, she continued to relapse. And when a bone marrow transplant seemed the only hope left, her disease was out of control and the treatment just wasn't possible. The Whiteheads were told by her medical team in Hershey, PA, nothing more could be done. They were instructed to take Emily home where she could die peacefully, surrounded by family.

But peaceful surrender didn't interest the Whiteheads; they rejected any version of giving up. It ran contrary to Tom Whitehead's vision of her recovery, something he said was revealed to him in the whispers. He saw, in a prophetic whispering dream, that Emily would be treated in Philadelphia. More importantly, he saw she would survive. It is as if it happened yesterday, said Tom, remembering how unrelentingly he called doctors at CHOP and said, We're coming there, no matter what you can or cannot do. We're not letting it end like this.

Since we treated Emily, we have treated more than 420 patients with CAR T cells at CHOP. She launched a whole group to be treated with this therapy; thousands have been treated around the world.Stephan Grupp, MD, PhD

A combination of persistence and perfect timing provided the magic bullet. It was just the day before that CHOP received approval to treat their first pediatric relapsed/refractory ALL patient with CAR T cells in a trial. And standing right there, on the threshold of history, was that deathly sick little girl named Emily.

At that time, only a scant few terminal adult patients had ever received the treatment, which is now FDA-approved as tisagenlecleucel and developed in cooperation with CHOP and the University of Pennsylvania. When three adults were treated, two experienced quick and complete remission of their cancers. Could CAR T-cell therapy perform a miracle for Emily? A lot would ride on the answer.

On March 1, 2012, Emily was transferred to CHOP and a few days later an apheresis catheter was placed in her neck; her T cells were extracted and sent to a lab. Emily received more chemotherapy, which knocked out her existing immune system, and she was kept in isolation for 6 weeks. Waiting.

Finally, over 3 days in April, Emily's re-engineered T cells, weaponized with chimeric antigen receptors, were infused back into her weakening body. But Emily did not rise like a Phoenix from the ashes of ALL. Instead, she sunk into the feverish fire of cytokine release syndrome (CRS), and experienced a worse-than-anticipated reaction. The hope for a swift victory seemed to be disappearing.

I can still see Emily's blood pressure dropping down to 53/29, her fever going up to 105F, her body swelling beyond recognition, her struggle to breathe, said Tom, of the most nightmarish period of his life. Doctors induced a coma, and Emily was put on a ventilator. For 14 days, her death seemed imminent. Doctors told us Emily had a one in a thousand chance of surviving, said Tom. They said she could die at any moment. But she didn't.

Medical team members who fought alongside the young patient are unwavering heroes in Emily's story. But at the time of her massive struggle, they too were exhausted and battle-scarred, descending into the quicksand of what could have been a failing trial, grasping for some life-saving branch of stability. They knew if CRS could be overcome, the CAR T cells might work a miracle as they had done for those earlier adult patients. But the CRS was severe. There was no obvious antidote; time was running out.

I recall Dr. June saying he believed Emily was past the point where she could come back and recover, said her father. And he said if she didn't turn around, this whole immunotherapy revolution would be over.

The Whiteheads enjoy Penn State football games not far from their hometown. The family has often taken part in Penn State's THON, a 48-hour dance marathon that raises funds for childhood cancer.

June confirmed to Oncology Times that he and Grupp believed Emily would not survive the night. It was mentioned to the Whiteheads that perhaps they should just concentrate on comfort care measures and stop all the ICU interventions, he recalled. I believed she was going to die on the trial due to all the toxicity. I even drafted a letter to our provost to give a heads up.

When the first patient in a trial dies, that's called a Grade 5 toxicity, June noted. That closes the trial as well. It goes right into the trash bin and you have to start all over again. But fortunately, that letter never left my outbox. We decided to continue one more day, and an amazing event happened.

Grupp, offering context to the mysterious amazing event, said it was clear that Emily's extreme CRS was caused by the infusion of cells that he himself had placed in her fragile body. He said he felt an enormous sense of responsibility and incredible urgency as he watched the child struggle to live.

It was not until the CHOP/Penn team received results from a test profiling cytokines in Emily's body that a new flicker of hope sparked. Though Emily had many cytokine abnormalities, the one most strikingly abnormal, interleukin-6 (IL-6), caught the team's attention. It is not made by T cells, and should not have been part of the critical mix. Though there were very few cytokines that had drugs to target them individually, IL-6 was one that did. So the doctors decided to repurpose tocilizumab, an arthritis drug, as a last-ditch effort at saving their young patient.

We treated Emily with tocilizumab out of desperation, June admitted. Steve [Grupp] has told me that when he went to the ICU with tocilizumab as a rescue attempt for CRS, the ICU docs called him a cowboy. The ICU docs had given up hope for Emily. But she turned aroundunbelievably rapidly. Today, tocilizumab is the standard of care for CRS, and the only drug approved by the FDA for that complication. Emily's recovery was huge for the entire field.

Grupp reflected on the immensity of the moment. If things had gone differently, if Emily had experienced fatal toxicity, it would have been devastating to her family and to the medical team. And it might have ended the whole research endeavor. It would have set us back years and years. The impact that Emily and her family had on the field is nothing short of transformational, he declared.

Since we treated Emily, we have treated more than 420 patients with CAR T cells at CHOP. She launched a whole group to be treated with this therapy; thousands have been treated around the world, Grupp noted. And, if not for Emily, we wouldn't be in the position we are in todaywith five FDA-approved [CAR T-cell] products: four for adults and one for kids. And I think it also important to point out that the very first CAR-T approval, thanks to Emily, was in pediatric ALL.

June noted that between 2010 and the time of Emily's treatment in 2012, My work was running like a shoestring operation. I had to fire people because I couldn't get grants to support the infrastructure of the research. It was thought there was no way beyond an academic enterprise to actually make customized T cells, then mail and deliver them worldwide, he recalled.

But then everything changed. We experienced that initial success; it was totally exciting. It was a career-defining moment and the culmination of decades of research. It led to a lot of recognition, both for my contribution and for the team here at the University of Pennsylvania and at CHOP.

Today, hundreds of pharmaceutical and biotech companies are developing innovations. Hundreds of labs are making next-generation approaches to improve in this area, June noted. Today, I'm a kid in a candy shop because all kinds of things are happening. We have funding thanks to the amazing momentum from Emily. She literally changed the landscape of modern cancer therapy.

Grupp said the continuing CAR T-cell program at CHOP offers evidence of success in a broad perspective. There are two things to look at, he offered. The first is how well patients do with their therapy in terms of getting into remission. A month after getting their cells, are they in remission or not? A study with just CHOP patients showed that more than 90 percent met that bar (N Engl J Med 2014; doi: 10.1056/NEJMoa1407222). Worldwide, the numbers appear to be in the 80 percent range (N Engl J Med 2018; doi: 10.1056/NEJMoa1709866). So, I would say it is a highly successful therapy.

We now have trials using different cell types, like natural killer cells, monocytes, and stem cells, noted Carl June, MD, at Penn's Perelman School of Medicine. An entirely new field has opened because of our initial success. This is going to continue for a long time, making more potent cells that cover all kinds of cancer.

The other big question, Grupp noted: How long does remission last? We are probably looking at about 50 percent of patients remaining in remission long-term, which is to say years after the infusion. The farther out we go, the fewer patients there are to look at because it just started with Emily in 2012, reminded Grupp. We have Emily now 10 years out, and other patients who are at 5, 6, 7, 8 years out, but most were treated more recently than that. We need to follow them longer.

June said registries of patients treated with CAR T-cell therapy are being kept worldwide by various groups, including the FDA. CAR T-cell therapy happened fastest in the U.S., but it's gained traction in Japan, Europe, Australia, and they all have databases. The U.S. database for CAR T cells will probably be the best that exists, because the FDA requires people treated continue follow-up for at least 15 years, he explained.

This will provide important information about any long-term complications, and the relapse rate. If patients do get cancer again, will it be a new one or related to the first one we treated? We will follow the outcomes, he noted. Clinicians are teaching us a lot about how to use the informationat what stage of the disease the therapy is best used, and which patients are most likely to respond. This can move us forward.

June mentioned that Grupp is collaborating with the Children's Oncology Group ALL Committee led by Mignon Loh, MD, at the University of California in San Francisco.

They are conducting a national trial to explore using CAR T cells as a frontline therapy in newly diagnosed patients, he detailed. Emily was treated when she had pounds and pounds of leukemia in her body; ideally we don't want to wait so long. There are a lot of reasons to believe it would work as a frontline therapy and spare patients all the complications of previous chemotherapy and/or radiation. The good news is that the clinical trial is under way, and I suspect we may know the answer within 2 years.

The only true measure of success in Emily's case is the state of her health. When asked if she is considered cured, June said, All we can do is a lot of prognostication. We know with other therapies in leukemia, the most similar being bone marrow transplants, if you go 5 years without relapsing, basically you are considered cured. We don't know with CAR T cells because Emily is the first one. We have no other history. But she's at a decade now, and in lab data we cannot find any leukemia in her. So by all of the evidence we haveand by looking in the magic eight ballI believe Emily is cured.

One might think that going through such a battle for life would be enough for any one person, any one family. But for Emily and her parents, her survival was just the beginning of a larger assault. All of them saw the experience as a way to provide interest in continuing research, education for patients as well as physicians, and an extension of hope to other patients about to succumb to a cancerous enemy.

Tom thought back to one particular occasion, all those years ago, when Emily finally slept peacefully through the night in her hospital bed. I should have felt nothing but relief, but I heard a mother crying in the hallway. Her child, who has been in the room next door, had died that morning, he recalled. I am constantly reminded of how fortunate we are. There are so many parents fighting for their children who do not have a good outcome.

As soon as Emily regained her strength and resumed normal childhood activities, the family began travelling with members of the medical team, joining in presentations at meetings and conferences throughout the world. They wanted to give a human face to the potential of CAR T-cell therapy, and as such they willingly became a powerful tool to raise understanding and essential research dollars. In 2016, the Whiteheads founded the Emily Whitehead Foundation (www.emilywhiteheadfoundation.org) ...to help fund research for new, less toxic pediatric treatments, and to give other families hope.

We decided to hold what we called the Believe Ball in 2017. We asked lots of companies to sponsor a child who had received CAR T-cell treatment to come with their family to the ball at no cost to them. Each company's representative would be seated with the child and family they sponsored, and would meet the doctors and scientists involved in the research, as well as members of industry and pharma, to see exactly where research dollars are going. We implored these companies to move the cancer revolution forward with sponsorship. When it all shook out, we had around 35 CAR T-cell families together for the first time, said Tom.

He noted proudly that since the foundation's debut, donations have been consistent and now have totaled an impressive $1.5 million.

When the Emily Whitehead Foundation had a virtual gala recently, it awarded a $50,000 grantthe Nicole Gularte Fight for Cures Ambassador Awardto a young researcher working to get another trial started. The award is named for a woman who found her way to CAR T-cell trials at Penn through the Whitehead Foundation. The treatment extended her life by 5 years during which time Gularte became an advocate for other cancer patients, travelled with the Whiteheads, and made personal appearances whenever she thought she could be of help or inspiration. Eventually, she would relapse and succumb, but she assured Tom Whitehead, These were 5 of the best years of my life. I think my time here on Earth was meant to help cancer research move forward.'

While raising funds for progress is important, the Whiteheads' work is not just about bringing in money. It's also about education.

We want to send a message to all oncologists; they need to be more informed about these emerging treatments when their patients ask for help, Tom noted. In the beginning of CAR T-cell therapy, a lot of doctors were against it. It's hard to believe, but some still are, though not as much. We need more education so that oncologists give patients a chance to get to big research hospitals for cutting-edge treatments before everything else has failed.

June said he regularly interacts with patients Tom or the foundation refer to him. Such unawareness happens with all new therapies, he noted. The people most familiar with them are at academic medical centers. But only about 10 percent of patients actually go to academic centers, the rest are in community centers where newer therapies take much longer to roll out, he explained.

So much of Emily's life has been chronicled through the eyes of observers. But since her watershed medical intervention, she has grown into a well-travelled, articulate young woman who talks easily about her life. I used to let my father do all the talking, but I am finding my own voice now, she said, having granted an interview to Oncology Times.

I'm currently 16 years old and I'm a junior at high school. Just like when I was younger, cows are my favorite animals, she offered with a laugh. I still love playing with our chihuahua, Luna. In school, I love my young adult literature class because I really like reading. Besides that, I like art and film. And I'm in really good health today.

She mentioned her health casually, almost as an afterthought. I really don't have any memory of my treatment at this point, she revealed, but, the experiences that I've had since then have really shaped who I am. Traveling is a huge part of my life now and something I look forward to. We've been to conferences at a lot of distant places. I'm so grateful that I get to travel with my family and make these memories that I will have forever, while still being able to advocate for less toxic treatment options and raising money for cancer research. All of that is really important to me.

Reminded that she has already obtained fame as pediatric patient No. 1 for CAR T-cell therapy, Emily considered her status for a moment then commented, I don't really like to base the progress of the therapy on my story and what I went through. Instead, I like to take my experience and use it to advocate for all patients so that what happened to me does not have to be repeated and endured by another family. My hope is that CAR T-cell therapy will become a frontline treatment option and be readily available, so pediatric patients can get back to a normal life as soon as possible. I want to tell people if conventional treatments do not work, other options do exist. Overall, I am grateful that I can encourage others to keep fighting. That's the main thing; I am grateful.

After a brief pause, Emily continued, I always tell oncologists and scientists that the work they are doing is truly saving children's lives. It allows these kids to grow up, be with their friends and families, take vacations, play with their dogs, and someday go to college, just like me. They are not only saving patients' lives, they are saving families. The work they do does not go unnoticed or unappreciated. Again, I am really so grateful.

Appreciation is a two-way street, and June said he and his team appreciate and draw inspiration from Emily on a daily basis. Her picture hangs on the wall of our manufacturing center, June stated. Some of the technicians who were in high school when Emily was infused are now manufacturing CAR T cells. They learned so much from Emily's experience; she continues to be a big motivator. She's helped my team galvanize and see that the work can really benefit people.

Grupp said the success that is embodied in Emily Whitehead has spurred additional successes, and new inroads in CAR T-cell therapy. There are more applications now, especially in other blood cancerslymphoma and myeloma, in addition to leukemia. We've seen a lot of expansion there.

He noted a national trial is under way for an FDA-approved therapy called idecabtagene vicleucel, which can benefit multiple myeloma patients. All other CAR Ts target the same target, CD19. But this goes after an entirely different target, BCMA. The fact that we now have approval in something that isn't aimed at CD19 is very exciting. And there are others coming right behind it.

The field also has seen further expansion ...into adults being treated safely, because initially there was concern that these drug therapies were too powerful for safe treatment in older adults, detailed Grupp. Now we know that is clearly not the case, and that is great news, particularly because multiple myeloma most often occurs in people over 60.

The use of CAR T cells in solid tumors continues to be challenging, although Grupp noted, We have certainly seen hints of patients with solid tumors having major responses and going into remission with CAR T cells. It is still a small handful of patients, so we haven't perfected the recipe for solid tumors yet. But I am absolutely confident we will have the answers in a very short numberperhaps 2-4of years.

June said, since Emily's infusion, CAR T cells have matured and gotten better. There are many ways that has happened, he informed. We have different kinds of CAR designs to improve and increase the response rates, to decrease the CRS, or to target other kinds of bone marrow cancers. One that is not curable with a lot of therapies is acute myeloid leukemia (AML), so we have a huge group at Penn and CHOP working on AML specifically. And there is the whole field of solid cancer; we have teams working on pancreatic, prostate, breast, brain, and lung cancer now.

In addition to targeting different types of cancer, June said contemporary research is also exploring the use of different types of cells. Our initial CAR T trial used T cells, and that is what all the FDA-approved CARs are. But we now have trials using different cell types, like natural killer cells, monocytes, and stem cells. An entirely new field has opened because of our initial success. This is going to continue for a long time, making more potent cells that cover all kinds of cancer, not just leukemia and lymphoma.

Is this the beginning of the end of cancer? Is this that Holy Grail called a cure to cancer? It's a question June has pondered.

Some people do think that, he answered. They believe the immune system is the solution. And that's a huge statement. President Biden has made a big investment in this work, with the Cancer Moonshot. He's accelerated this research at the federal level. But we just don't know how long it is going to take. Fortunately, a lot of good minds are working hard to make an end to cancer a reality.

As the battle grinds on, June said he applies something he's learned over time, with reinforcement from Tom and Kari Whitehead. They were bulldogs. When it came to getting treatment for Emily, they just wouldn't take no for an answer. They demonstrated the importance of never giving up. That's what happened; they would not surrender. I think that is why Emily is alive today.

Valerie Neff Newitt is a contributing writer.

The Emily Whitehead Foundation and the Whitehead family take extraordinary advantage of a variety of media to reach patients and physicians and optimize educational opportunities.

Here is the original post:
The Incredible Story of Emily Whitehead & CAR T-Cell Therapy : Oncology Times - LWW Journals

Theranostics. 2020; 10(8): 36223635.

Institute of Molecular and Cell Biology, 61 Biopolis Drive, 138673, Singapore

Competing Interests: The authors have declared that no competing interest exists.

Received 2019 Oct 4; Accepted 2019 Dec 20.

The transcriptional co-regulators YAP and TAZ pair primarily with the TEAD family of transcription factors to elicit a gene expression signature that plays a prominent role in cancer development, progression and metastasis. YAP and TAZ endow cells with various oncogenic traits such that they sustain proliferation, inhibit apoptosis, maintain stemness, respond to mechanical stimuli, engineer metabolism, promote angiogenesis, suppress immune response and develop resistance to therapies. Therefore, inhibiting YAP/TAZ- TEAD is an attractive and viable option for novel cancer therapy. It is exciting to know that many drugs already in the clinic restrict YAP/TAZ activities and several novel YAP/TAZ inhibitors are currently under development. We have classified YAP/TAZ-inhibiting drugs into three groups. Group I drugs act on the upstream regulators that are stimulators of YAP/TAZ activities. Many of the Group I drugs have the potential to be repurposed as YAP/TAZ indirect inhibitors to treat various solid cancers. Group II modalities act directly on YAP/TAZ or TEADs and disrupt their interaction; targeting TEADs has emerged as a novel option to inhibit YAP/TAZ, as TEADs are major mediators of their oncogenic programs. TEADs can also be leveraged on using small molecules to activate YAP/TAZ-dependent gene expression for use in regenerative medicine. Group III drugs focus on targeting one of the oncogenic downstream YAP/TAZ transcriptional target genes. With the right strategy and impetus, it is not far-fetched to expect a repurposed group I drug or a novel group II drug to combat YAP and TAZ in cancers in the near future.

Keywords: TEAD, YAP, TAZ, Hippo, cancer therapy

The transcriptional co-regulators YAP (Yes-associated protein) and TAZ (transcriptional co-activator with PDZ-binding motif) are key players that mediate various oncogenic processes and targeting their activities has emerged as an attractive option for potential cancer therapy. YAP, as the name suggests, was initially identified as a protein that associates with Yes, a src family kinase (SFK) 1. The exact function of YAP remained elusive until it was demonstrated to be a potent transcriptional activator 2. YAP's paralog TAZ, identified from a screen for 14-3-3 interacting proteins, is also a transcriptional co-activator 3 (Figure ).

The oncogenic milestones of the transcriptional co-regulators YAP and TAZ. Discovery of YAP/TAZ and TEAD functions predate the discovery of the Hippo pathway. Role of YAP/TAZ in the Hippo pathway and the discovery of their oncogenic abilities in cell and animal models are considered significant. The initial studies from the groups that linked YAP/TAZ to oncogenic signaling pathway, stemness, actin cytoskeleton, fusion genes, drug resistance, metabolism, angiogenesis and immune suppression are also listed.

YAP and TAZ do not have a DNA-binding domain and they need to associate with a transcription factor in order to access DNA. It has now emerged that YAP/TAZ use predominantly the TEAD (TEA domain) family of transcription factors 4 to elicit most of their biologically relevant gene expression programs. ChIP-Seq data unraveled a significant overlap in YAP/TAZ and TEAD peaks throughout the genome, and also showed that some YAP/TAZ-responsive genes are also synergistically regulated by AP-1 transcription factors 5, 6. In addition to its interaction with TEADs, YAP/TAZ also communicates with the mediator complex and chromatin modeling enzymes like the methyltransferase and SWI/SNF complex to elicit changes in gene expression 7-9. YAP/TAZ also suppress gene expression and should be regarded as co-regulators rather than co-activators 10.

YAP/TAZ are now considered as effectors of a physiologically and pathologically important signaling pathway - popularly called the Hippo pathway 11. The Hippo pathway was initially identified in a genetic mosaic screen in Drosophila but the pathway components are evolutionarily conserved. It is now known that the primary function of the Hippo pathway is to suppress the activity of Yorkie - the Drosophila homolog of YAP 12. The Hippo pathway in mammals also inhibits YAP/TAZ through phosphorylation by the large tumor suppressor (LATS) family of Hippo core kinases 13, which leads to cytoplasmic sequestration via interaction with 14-3-3 proteins and/or degradation via ubiquitin proteasome pathway 14, 15.

YAP and TAZ were first shown to transform mammary epithelial cells 16, 17. The oncogenic role of YAP became apparent when it was shown to be a driver gene in a mouse model of liver cancer 18 (Figure ). In a conditional transgenic mouse model, YAP overexpression dramatically increases liver size and the mouse eventually develops hepatocellular carcinoma 19, 20. In addition to causing primary tumor growth, YAP also helps in the metastatic dissemination of tumor cells 21.

Over a decade of research has revealed that YAP/TAZ integrates the inputs of various oncogenic signaling pathways, such as EGFR, TGF, Wnt, PI3K, GPCR and KRAS. Through expression of the ligand AREG, YAP was first shown to communicate with the EGFR pathway 22 (Figure ). The genes regulated by YAP/TAZ collectively coordinate various oncogenic processes, such as stemness, mechanotransduction, drug resistance, metabolic reprogramming, angiogenesis and immune suppression (Figure ), many of which are considered to be cancer hallmarks 23.

YAP and TAZ regulate the expression of crucial transcription factors like Sox2, Nanog and Oct4 and are able to maintain pluripotency or stemness in human embryonic stem cells (ESCs) and in induced pluripotent stem (iPS) cells 24, 25 (Figure ). More specifically, TAZ has been shown to confer self- renewal and tumorigenic capabilities to cancer stem cells 26. Within the microenvironmental landscape of tissues, YAP/TAZ are increasingly recognized as mechanosensors that respond to extrinsic and cell-intrinsic mechanical cues. To this end, mechanical signals related to extracellular matrix (ECM) stiffness, cell morphology and cytoskeletal tension rely on YAP/TAZ for a mechano-activated transcriptional program 27-29. YAP/TAZ target genes, CTGF and CYR61, cause resistance to chemotherapy drugs like Taxol 30 and YAP/TAZ has emerged as a widely used alternate survival pathway that is adopted by drug-resistant cancer cells 31. YAP/TAZ activity is regulated by glucose metabolism and is connected to the activity of the central metabolic sensor AMP-activated protein kinase (AMPK) 32-35. YAP/TAZ reprograms glucose, nucleotide and amino acid metabolism in order to increase the supply of energy and nutrients to fuel cancer cells 36. Through expression of proangiogenic factors like VEGF and angiopoetin-2 37, 38, YAP is able to stimulate blood vessel growth to support tumor angiogenesis 39. YAP is also shown to recruit myeloid-derived suppressor cells in prostate cancers in order to maintain an immune suppressive environment 40. Active YAP also recruits M2 macrophages to evade immune clearance 41.

A TAZ fusion gene (TAZ-CAMTA1) alone, in the absence of any other chromosomal alteration or mutation, is sufficient to drive epithelioid hemangioendothelioma (EHE), a vascular sarcoma 42, 43. Furthermore, comprehensive analysis of human tumors across multiple cancer types from the TCGA database unraveled that YAP and TAZ are frequently amplified in squamous cell cancers in a mutually exclusive manner 44. In human cancers, there is also a good correlation between YAP/TAZ target gene signature and poor prognosis. To date, a proportion of every solid tumor type has been shown to possess aberrant YAP/TAZ activity. Further, many of the upstream Hippo components that negatively regulate YAP/TAZ are found inactivated across many cancer types 45. Thus, all of this paint a clear picture of the prominent role played by YAP and TAZ at the roots of cancers 46, 47.

There are more than fifty drugs that have been shown to inhibit YAP/TAZ activity 48, however, with the exception of verteporfin; none act directly on YAP/TAZ. The unstructured nature of YAP and TAZ renders them difficult to target using small molecules. Therefore, YAP/TAZ inhibition is achieved indirectly through targeting their stimulators or partners. In this review, we focus on small molecules, antibody and peptide-based drugs, as the majority of the drugs in the clinic belong to this class. Less attention is given to nucleotide-based molecules and to small molecule YAP/TAZ inhibitors whose targets are unknown. We classify the YAP/TAZ-inhibiting drugs into three groups with each group having its own combating strategy to counter YAP/TAZ activity (Figure ). Group I drugs target the upstream YAP/TAZ stimulators and enhance the LATS-dependent inhibitory phosphorylation of YAP/TAZ in order to restrain their transcriptional output. Group II drugs/candidates act directly on YAP/TAZ or TEAD and may either interfere with the formation of the YAP/TAZ-TEAD complex or inhibit TEADs directly and hence affect YAP/TAZ-TEAD transcriptional outcomes. Group III drugs' combat strategy is to target the oncogenic proteins that are transcriptionally upregulated by YAP and TAZ.

Classification ofYAP/TAZ-TEAD inhibiting drugs into three groups. Group I drugs (red font) act upstream and prevent the nuclear entry of YAP and TAZ, group I drug targets for potential pharmacological exploitation in order to generate repurposed YAP/TAZ-inhibiting drugs are circled. Group II drugs (green font) disrupt the formation of the YAP/TAZ-TEAD complex and they primarily bind to the TEAD family of transcription factors. Group Ill drugs (blue font) act on the downstream transcriptional targets in order to prevent YAP/TAZ-mediated oncogenicity.

Group I drugs target the upstream proteins (Figure ), inhibition of which culminates in the enhancement of the LATS-dependent inhibitory phosphorylation of YAP/TAZ 49, 50. However, some group I targets like SFKs 51-53, AMPK 33, 34 and phosphatases 54-56 act directly on YAP and TAZ and activate them. Majority of group I drugs are kinase inhibitors, in addition to restricting YAP/TAZ nuclear entry; they intriguingly promote TAZ, but not YAP degradation. A possible explanation for this is the presence of two phosphodegrons that render TAZ more prone to degradation 15. Some group I drugs, such as MEK/MAPK inhibitors 57, 58 and -secretase inhibitors (GSIs) 59 have the ability to actively reduce both YAP and TAZ levels. HDAC inhibitors however, reduce YAP, but not TAZ levels 60. Here, we have classified the group I drugs based on the nature of the drug target.

Drugs targeting the EGFR, GPCR, Integrin, VEGFR and adenylyl cyclase families as well as those targeting receptors like the -secretase complex and Agrin are shown to inhibit YAP/TAZ activity 51, 61-64.

YAP/TAZ exploits the transformative abilities of the ErbB receptors (EGFR family) to drive cell proliferation. By transcribing ErbB ligands, such as AREG 22, 65, TGF- 66, NRG1 67 as well as the ErbB receptors EGFR and ErbB3 67, YAP is able to activate ErbB signaling and promote tumorigenesis. Sustained EGFR signaling also disassembles the Hippo core complexes leading to an increased active pool of YAP/TAZ 68 that is ready to transcribe more ErbB ligands/receptors. Under these conditions, EGFR inhibitors like Erlotinib 22 and AG-1478 66 (Figure ) are able to act as YAP/TAZ inhibitors and may be used for EGFR-driven cancers requiring YAP/TAZ transcription.

Signaling from G-protein coupled receptors (GPCRs), transduced by the associated G subunit or by the G subunits, modulates YAP/TAZ activities 69. Inhibiting Gq/11 sub-type signaling, using losartan 70, or stimulating Gs sub-type, using dihydrexidine, has been shown to stimulate YAP inhibitory phosphorylation 69. Agonism of Gs has been recently exploited to facilitate YAP/TAZ inhibition that reverses fibrosis in mice 71. G inhibition using gallein has also been shown to restrict YAP/TAZ 72. Activating mutations in the Gq/11 types of GPCRs present in approximately 80% of the uveal melanoma patients generate an active pool of YAP 73, 74 but the signal transduction occurs via Trio-Rho/Rac signaling and not through the canonical Hippo pathway 74.

Integrin signaling negatively regulates the Hippo pathway complexes to drive YAP/TAZ activity 75, 76. Although blocking integrin activity using RGD peptides 63, cilengitide (cyclic RGD peptide) 77, function-blocking antibodies - BHA 2.1 76 and clone AIIB2 78 has been shown to increase YAP/ TAZ's inhibitory phosphorylation, disappointingly, the efficacy of integrin- blocking drugs against cancers has not been clinically proven 79. Interestingly, a function-blocking antibody against Agrin, an extrinsic stimulator of integrin signaling, abrogates YAP-dependent proliferation in mouse models 63, 80.

Among the kinase inhibitors tested in a biosensor screen for LATS activity, the VEGFR inhibitors are shown to potently activate LATS and thereby inhibit YAP and TAZ activity 81. Further, VEGFR2 signaling is also shown to induce actin cytoskeletal changes and promote YAP/TAZ activation 82. Therefore, VEGFR inhibitors like SU4312, Apatinib, Axitinib and pazopanib are able to inhibit the expression of YAP/TAZ-responsive genes in endothelial cells. But whether these drugs work as YAP/TAZ inhibitors in cancer cells remains to be seen.

Enhancing cyclic AMP (cAMP) levels using the adenylyl cyclase activator forskolin activates the LATS kinases through Protein kinase A (PKA) and Rho 69, therefore forskolin is also a YAP/TAZ inhibitor. cAMP is degraded by the cyclic nucleotide phosphodiesterases (PDE), the use of PDE inhibitors like theophylline, IBMX, ibudilast and rolipram also promotes YAP/TAZ-inhibitory phosphorylation 83, 84.

Notch and YAP/TAZ signaling are also closely linked, inhibiting notch activity by targeting the -secretase complex, either using DAPT or dibenzazepine has been shown to decrease YAP/TAZ expression levels in mouse livers and also reduce YAP activation and YAP-induced dysplasia in the intestine 20, 51, 59.

Integrin signaling activates focal adhesion kinase (FAK), SFK and integrin- linked kinase (ILK). Growth factor and GPCR signaling occurs through mitogen-activated protein kinase (MAPK) and phosphoinositide 3-OH kinase (PI3K) signaling. There is also significant crosstalk in the signaling from these membrane receptors. Given the availability of potent small molecule drugs targeting the downstream kinases, they are leveraged on to inhibit YAP or TAZ activities.

Members of downstream integrin signaling pathway including FAK, its counterpart PYK2, and ILK have emerged as negative regulators of the core Hippo pathway and thus activate YAP/TAZ. Membrane receptors, such as ErbB and GPCRs are unable to activate YAP upon genetic deletion of ILK. Therefore, pharmacological inhibition of ILK using a specific ILK inhibitor, QLT0267 potently inhibits YAP-dependent tumor growth in xenograft models 85. The FAK inhibitors PF-562271 and PF-573228 have also been shown to enhance the LATS-mediated inhibitory phosphorylation of YAP 63, 75. A multi-kinase inhibitor CT-707 that predominantly inhibits FAK, anaplastic lymphoma kinase (ALK) and PYK2 is able to render cancer cells vulnerable to hypoxia through YAP inhibition 86. Inhibiting PYK2 activity using the dual PYK2/FAK inhibitor PF431396 destabilizes TAZ and also inhibits YAP/TAZ activity in triple negative breast cancer cells 87.

The SFK member Src prevents the activation of LATS 75, 88, thereby relieves YAP/TAZ inhibition by LATS. Interestingly, SFKs, Src and YES are also shown to activate YAP through direct tyrosine phosphorylation 51-53. Treating cells with SFK inhibitors, such as Dasatinib, PP2, SU6656, AZD0530 and SKI-1 inactivates YAP 51-53, 75, 88. In -catenin-driven cancers, YES facilitates the formation of a tripartite complex comprising -catenin, YAP and TBX5 that drives cell survival and tumor growth 53, 89. The SFK inhibitor dasatinib also serves as YAP inhibitor in these cancers 53. Dasatinib, in addition to inhibiting SFKs may also potently inhibit PDGFR and Ephrin receptors, both of which are known to activate YAP/TAZ 90, 91. However, FAK and SFK inhibitors have shown very limited efficacy against solid tumors in clinical trials therefore their utility in YAP-driven cancers remains to be seen.

MEK (MAP kinase kinase) and YAP interact with each other and maintain transformed phenotypes in liver cancer cells 57. MEK inhibitors PD98059, U0126 and trametinib or MAPK inhibitors CAY10561 and {"type":"entrez-nucleotide","attrs":{"text":"FR180204","term_id":"258307209","term_text":"FR180204"}}FR180204 are able to trigger degradation of YAP in a Hippo-independent manner 57, 58. The finding that MEK inhibition causes YAP degradation is, however, difficult to reconcile if YAP and TAZ are shown to mediate resistance to the MEK inhibitor trametinib 92. The efficacy of trametinib is also being evaluated in EHE, a cancer that is caused by the TAZ-CAMTA1 fusion gene ({"type":"clinical-trial","attrs":{"text":"NCT03148275","term_id":"NCT03148275"}}NCT03148275).

PI3K inhibitors Wortmannin/LY294002 as well as the drug BX795, an inhibitor of its effector 3'-phosphoinositide-dependent kinase-1 (PDK1) prevents nuclear entry of YAP 68. PI3K is closely linked to the mammalian target of rapamycin (mTOR) pathway. mTOR inhibitors temsirolimus and MLN0128 have been shown to inhibit YAP activity in patients with idiopathic pulmonary fibrosis and in a mouse model of cholangiocarcinoma, respectively 93, 94. YAP levels in TSC1 mutant mouse could also be reduced by blocking mTOR using torin1 treatment that induces the autophagy-lysosomal pathway 95.

YAP/TAZ inhibition is an additional unexpected activity possessed by the few kinase inhibitors mentioned above. However, apart from YAP/TAZ inhibition, all other signaling events initiated by the target kinase are also shut down due to inhibitor treatment. If these signaling events are critical for cellular homeostasis, then, toxic side effects will outweigh clinical benefits and this cannot be uncoupled from YAP/TAZ inhibition. Therefore, kinase inhibitors that failed in the trials due to unacceptable toxcity or poor pharmacokinetics may not be repurposed as YAP/TAZ inhibitors in the clinic. Focus should be on the kinase inhibitors that are already in the clinic like EGFR, VEGFR, MEK, PI3K or mTOR inhibitors but efficacy needs to be proven in order to repurpose them as YAP/TAZ inhibitors. The kinase targeted by the inhibitor must activate YAP/TAZ in tumors, for the treatment to be efficacious and this restricts the use of kinase inhibitors to selective tumor types. Intriguingly, YAP/TAZ activation has emerged as a prominent survival strategy adapted by cancers that cause drug resistance to EGFR and its downstream MEK/MAPK inhibitors 31. In such scenarios, coupling a group II YAP/TAZ inhibitor with a EGFR pathway inhibitor might offer the intended treatment benefits.

The mevalonate pathway is essential for the biosynthesis of isoprenoids, cholesterol and steroid hormones. Statins as well as other mevalonate pathway inhibitors like zoledronic acid and GGTI-298 that target farnesyl pyrophosphate synthase and geranylgeranyltransferase, respectively are identified as drugs that restrict the nuclear entry of YAP and TAZ 96, 97. Studies have also shown that combining statins like simvastatin with the EGFR inhibitor gefitinib provides stronger anti-neoplastic effects 98. Atorvastatin and zoledronic acid have entered Phase II clinical trials in triple negative breast cancer to test if they improve the pathological complete response rates ({"type":"clinical-trial","attrs":{"text":"NCT03358017","term_id":"NCT03358017"}}NCT03358017).

Actin polymerization promotes YAP/TAZ nuclear localization and therefore, polymerization inhibitors like latrunculin A 27 and cytochalasin D 28, 29 inhibit YAP/TAZ. Myosin or myosin light-chain kinase inhibitors like blebbistatin and ML-7, respectively have a similar effect 27, 29. Interfering with the actomyosin cytoskeleton through other means, such as Rho inhibition (toxin C3 treatment), or by using Rho kinase inhibitors like Y27632 has also been shown to have an inhibitory effect on YAP/TAZ 27, 29. p21 activated kinase (PAK) family kinases are cytoskeletal regulators as well as Hippo inhibitors. The PAK allosteric inhibitor IPA3 prevents YAP's nuclear entry 63, 99, further, the PAK4 inhibitor PF-03758309 is also shown to reduce YAP levels 77.

YAP/TAZ inhibitory phosphorylation is dynamic and the protein phosphatases PP1 and PP2A are shown to associate with YAP/TAZ and aid in their dephosphorylation and activation. Inhibiting these phosphatases using okadaic acid or calyculin A increases YAP/TAZ phosphorylation and shifts YAP/TAZ to the cytoplasm 54-56. Some of the oncogenic functions of YAP/TAZ are also mediated by the protein-tyrosine phosphatase SHP2 100, therefore SHP2 inhibitors have also been shown to attenuate YAP/TAZ activity 101.

Cellular energy stress is closely linked with attenuation of YAP/TAZ activities 32. Drugs that enhance energy stress like the mitochondrial complex I inhibitors metformin and phenformin, enhance YAP/TAZ inhibitory phosphorylation, cytoplasmic localization and suppression of YAP/TAZ- mediated transcription 32. The energy stress induced by these drugs activates AMPK, which is shown to phosphorylate and stabilize AMOTL1 - a YAP/TAZ negative regulator 32. AMPK is also shown to directly phosphorylate and inactivate YAP by disrupting its interaction with TEADs 33, 34. Therefore, AMPK activators A769662 and AICAR (an AMP-mimetic) are YAP inhibitors 32-34.

Histone deacetylases (HDACs) are uniquely positioned to alter the transcription of target genes. Interestingly, HDAC inhibitors panobinostat, quisinostat, dacinostat, vorinostat and Trichostatin A transcriptionally repress the expression of YAP but not TAZ, and thereby reduce YAP-addicted tumorigenicity 60. Treatment of cholangiocarinoma cells with the HDAC inhibitor {"type":"entrez-nucleotide","attrs":{"text":"CG200745","term_id":"34091806","term_text":"CG200745"}}CG200745 is also shown to decrease YAP levels 102. Although HDAC inhibitors are used to treat hematological malignancies their efficacy in solid cancers is questionable, however, combining HDAC inhibitor panobinostat with BET (bromodomain and extra-terminal) inhibitor I-BET151 achieves more effective YAP inhibition 103. There is also a clinical trial designed to evaluate the efficacy of HDAC/BET inhibitor combination in solid tumors and determination of YAP expression level after drug treatment is used as one of the objectives ({"type":"clinical-trial","attrs":{"text":"NCT03925428","term_id":"NCT03925428"}}NCT03925428). The BET family protein BRD4 is a part of the YAP/TAZ-TEAD transcriptional complex and inhibiting BRD4 using BET inhibitor JQ1 inhibits YAP upregulation and YAP-mediated transcription in KRAS mutant cells 104.

Many group I drugs can potentially be repurposed to treat YAP/TAZ- driven cancers 105. Among the group I drugs, only statins, trametinib and HDAC/BET inhibitors are being evaluated in clinical trials to test if they act against YAP/TAZ. Our prediction is that group I drugs that facilitate YAP/ TAZ inhibitory phosphorylation as well as degradation will have greater success in combating YAP/TAZ in cancers as YAP/TAZ degradation prevents their reactivation through other mechanisms. Importantly, the repurposing of group I drugs would also allow YAP/TAZ and its target gene(s) expression-based stratification amongst cancer patients.

Modalities that target either the TEAD family of transcription factors or YAP/TAZ are classified under this group (Figure ). The majority of the modalities, with the exception of verteporfin 106, target TEADs and are therefore predicted to act in the nucleus. By pairing with the TEAD family of transcription factors, YAP and TAZ upregulate the expression of many oncoproteins. The C-terminus of all TEADs possesses the YAP/TAZ-binding domain. The partnership between YAP/TAZ and TEAD is essential for the initiation of transcriptional program to drive oncogenesis. YAP is no longer oncogenic when sequestered by a dominant negative TEAD that lacks the DNA-binding domain 106. Similarly, a naturally occurring DNA-binding deficient TEAD isoform is also able to inhibit YAP/TAZ-mediated oncogenicity 107. Therefore, directly inhibiting TEAD or preventing YAP/TAZ-TEAD interaction is a promising and most direct strategy that warrants special attention 108.

Disruptors, stabilizers and destabilizers/degraders. A preformed YAP/TAZ-TEAD complex prevents access to drugs that occupy either the TEADs' surface or the palmitate-binding pocket (PBP), however, unassembled TEADs are accessible to drugs. Majority of the known YAP/TEAD-binding compounds are disruptors as they prevent the formation of the YAP/TAZ-TEAD complex. Two other classes of TEAD-binding compounds are stabilizers and destabilizers/degraders. Stabilizers either stabilize TEAD expression levels or enhance the formation of the YAP/TAZ-TEAD complex. Destabilizers bind to TEADs' surface or PBP and reduce TEAD expression levels through in situ denaturation, degraders on the other hand direct TEADs for proteasomal degradation.

Group I drugs target the upstream YAP/TAZ-activating proteins like the EGFR, GPCR, Src, or Integrins. As there are so many upstream YAP/TAZ activators, group I drugs are vulnerable to oncogenic bypass where inhibition of one group I YAP/TAZ activator leads to selection of cancer cells that activate YAP/TAZ via another group I activator. Strategically, Group II drugs may address this issue by directly targeting YAP/TAZ or TEAD, the converging points for various pathways and also the effectors for oncogenic transcription. However, Group II targeting modalities are still at the exploratory stage and it remains to be seen whether it is feasible to develop a Group II modality that works in clinic. We also need to be mindful of the possible associated toxicities due to YAP/TAZ-TEAD inhibition 109.

Most of the reported Group II modalities are disruptors; they target YAP/TAZ or TEAD and prevent their binary interaction. However, in addition to disruptors, in the future, we predict the emergence two other classes of group II compounds that would act as TEAD stabilizers and destabilizers/degraders (Figure ).

A small molecule benzoporphyrin drug named Verteporfin (VP) was shown to have the ability to bind to YAP and disrupt the YAP-TEAD interaction 106. VP is also able to inhibit YAP-induced excessive cell proliferation in YAP- inducible transgenic mice and in NF2 (upstream Hippo pathway component) liver-specific knockout mouse models 106. Although we do not understand the molecular details of VP binding to YAP, it is still undoubtedly the most popular YAP inhibitor within the scientific community. However, we need to be cautious as some of the tumor-inhibitory effects of VP are reported to be YAP- independent 110, 111. VP is photosensitive and proteotoxic and there is a need for better derivatives. A VP derivative, a symmetric divinyldipyrrine was shown to inhibit YAP/TAZ-dependent transcription but it is not clear if the compound specifically binds to YAP 112.

YAP and TAZ bind on the TEADs' surface; Inventiva Pharma has identified several compounds with benzisothiazole-dioxide scaffold that bind to the TEADs' surface and disrupt the YAP/TAZ-TEAD interaction. These compounds are currently in the lead optimization stage and have the potential to treat malignant pleural mesothelioma as well as lung and breast cancers that are driven by YAP/TAZ 113.

YAP cyclic peptide (peptide 17) and cystine-dense peptide (TB1G1) are also disruptors of YAP/TAZ-TEAD interaction in vitro but they have poor cell-penetrating abilities 114, 115. Interestingly, a peptide derived from the co-regulator Vgll4 appears to have remarkable cell-penetrating abilities and inhibits YAP-mediated tumorigenesis in animal models 116. Vgll proteins, named Vgll1-4 in mammals, belong to another class of co-regulators that pair with TEADs in a structurally similar, and therefore, in a mutually exclusive manner with YAP and TAZ 117, 118.

We identified a novel druggable pocket in the center of the TEADs' YAP/TAZ- binding domain 119 that could be occupied by fenamate drugs. Palmitate was subsequently shown to occupy this pocket, hereafter referred to as the palmitate-binding pocket (PBP). TEAD palmitoylation is shown to be important for stability and for the interaction with YAP 120, 121. Although the fenamate drug flufenamic acid competes with palmitate for binding to TEAD, higher concentrations are needed for it to be effective and it is not a disruptor of the interaction between YAP/TAZ with TEADs 122. However, covalently linking the fenamate to TEAD, using a chloromethyl ketone substitution, enables it to disrupt the YAP-TEAD interaction 123. The non-fused tricyclic compounds identified by Vivace Therapeutics could also be considered as fenamate analogs but it remains to be seen if they function as disruptors 124. Through structure-based virtual screen, vinylsulfonamide derivatives were identified as compounds that bind to PBP 125. Optimization of these derivatives yielded DC-TEADin02 a covalent TEAD autopalmitoylation inhibitor with an IC50 value of 200 nM. Interestingly, DC-TEADin02 is able to inhibit TEAD activity without disrupting the YAP-TEAD interaction.

Palmitate, by occupying the PBP, allosterically modulates YAP's interaction with TEAD 121, therefore it is conceivable that there might be small molecules that occupy the PBP and allosterically disrupt YAP/TAZ's interaction with TEADs. To this end, Xu Wu's group has identified and patented several potent compounds with alkylthio-triazole scaffold as PBP- occupying compounds that prevent YAP-TEAD interaction in cells 126. Another potent TEAD inhibitor that occupies the PBP is the small molecule K-975 127. K-975 also disrupts the YAP-TAZ-TEAD interaction and displayed anti-tumorigenic properties in malignant pleural mesothelioma cell lines much akin to the loss of YAP. Although palmitate is covalently attached to TEAD, it is a reversible modification and addition of PBP-occupying small molecules reduce the cellular palmitoylation status of TEADs 126. Moreover, the palmitoyl group is also removed from TEADs by depalmitoylases 128.

Being predominantly unstructured, YAP and TAZ are difficult to target directly. However, TEADs offer two attractive ways for targeting, one is to directly block the YAP/TAZ-binding pocket on the TEADs' surface with small molecules or peptides, whilst the other is to leverage on the PBP and allosterically disrupt YAP/TAZ interaction or inhibit TEADs (Figure ). However, the molecular determinants that confer YAP/TAZ disrupting ability to PBP-occupying small molecules are not clear. We do not know why flufenamate and DC-TEADin02 are unable to disrupt YAP/TAZ-TEAD interaction, like chloromethyl fenamate, K-975 and compounds with alkylthio-triazole scaffold.

The PBP could also be leveraged to allosterically enhance YAP/TAZ-TEAD stability or interaction. This prediction is subject to the identification of small molecules that functionally mimic the ligand palmitate (Figure ). Compounds with such an ability will enhance TEAD-dependent transcription and may have therapeutic value for regenerative medicine where enhancement of YAP/TAZ- TEAD activity is needed to repair damaged tissues 129. We recently identified that quinolinols occupy the PBP, stabilize YAP/TAZ levels and upregulate TEAD-dependent transcription 130. Enhanced YAP/TAZ levels increase the pool of assembled YAP/TAZ complex and therefore quinolinols could be considered as stabilizers (Figure ).

We identified a few chemical scaffolds that have the ability to occupy the PBP and destabilize TEAD (unpublished results). Addition of these compounds unfolds the TEADs' YAP/TAZ-binding domain and we call these compounds destabilizers (Figure ). Degraders could be generated when potent and selective TEAD surface or PBP-occupying compounds are coupled to proteolysis targeting chimera (PROTAC) 131 to direct TEAD proteasomal degradation. Therefore, destabilizers aim to reduce the cellular concentration of TEADs through in situ unfolding and degraders reduce TEAD levels through proteasomal degradation. Reducing the levels of their interacting partners deprives YAP/TAZ of their ability to activate transcription.

Any TEAD-binding compounds (disruptors, stabilizers or destabilizers/degraders) can only access unbound TEADs, as binding of YAP and TAZ blocks both the surface and the palmitate-binding pockets (Figure ). After accessing unbound TEADs, the disruptors and destabilizers/degraders reduce, whereas the stabilizers enhance, the formation of the YAP/TAZ-TEAD complex.

YAP/TAZ-mediated tumor development is due to the collective action of the repertoire of proteins that are expressed under their influence. However, some proteins are able to drive oncogenesis much better than others and they vary depending on the solid tumor and context. Therefore, drugs against these downstream YAP/TAZ targets including metabolic enzymes, kinases, ligands and proteins, such as BCL-xL, FOXM1 and TG2 are also used to combat YAP/TAZ-mediated oncogenicity (Figure ).

TAZ-dependent expression of ALDH1A1 (aldehyde dehydrogenase) is shown to impart stemness and tumorigenic ability; inhibition of ALDH1A1 using A37 reverses this transformation 132. GOT1 - the aspartate transaminase induced by YAP/TAZ, confers glutamine dependency to breast cancer cells and targeting this metabolic vulnerability using aminooxyacetate (AOA) represses breast cancer cell proliferation 133. Targeting the YAP/TAZ transcriptional target cyclooxygenase 2 (COX-2) using celecoxib inhibits cell proliferation and tumorigenesis in NF2 mutant cells 134. Interestingly, a positive feedback is seen in hepatocellular carcinoma cell lines where COX-2 is also shown to increase the expression of YAP 135. Inhibiting COX-2 using NS398 stimulates LATS-dependent phosphorylation of TAZ 136.

In hepatocellular carcinoma, Axl kinase has been shown to be crucial for mediating several YAP-driven oncogenic functions like cell proliferation and invasion 137. Similarly, YAP-driven Axl expression has been implicated in the development of resistance against EGFR inhibitors in lung cancer and sensitivity could be restored through Axl inhibition using TP-0903 138. YAP is shown to upregulate the expression of the kinase NUAK2 139 that, in turn activates YAP/TAZ by inhibiting LATS. Specific pharmacological inhibition of NUAK2 using WZ400 shifts YAP/TAZ to the cytoplasm and reduces cancer cell proliferation 140.

In a mouse model of prostate adenocarcinoma, the YAP-TEAD complex promotes the expression of the chemokine ligand CXCL5 that facilitates myeloid-derived suppressor cells (MDSC) infiltration and adenocarcinoma progression. Administering CXCL5 neutralizing antibody, or blocking CXCL5 receptor using the inhibitor SB255002, inhibits MDSC migration and tumor burden 40. The notch ligand Jagged-1 that is upregulated by YAP/TAZ is crucial for liver tumorigenesis 59, 141. Treating liver tumor cells with Jagged-1 neutralizing antibody greatly reduces oncogenic traits. The levels of integrin ligands CTGF and CYR61 that are also YAP target genes, could be reduced using the cyclopeptide RA-V (deoxybouvardin) leading to a reduction of YAP- mediated tumorigenesis in mst1/2 (Hippo homolog) knockout mouse model 142. Although neutralizing CTGF (FG-3019/pamrevlumab) and CYR61 (093G9) antibodies are available, they have not been effectively used against YAP/TAZ-driven cancers.

YAP mediates drug resistance to RAF- and MEK-targeted therapies in BRAF V600E cells, in part through the expression of the anti-apoptotic protein BCL- xL. BCL-xL inhibition using navitoclax sensitizes these cells to targeted therapies 92.

YAP-mediated proliferation through its target gene FOXM1 could be prevented in sarcoma cell lines and mouse models through the administration of thiostrepton that reduces FOXM1 levels 143.

Transglutaminase 2 (TG2) - the multifunctional transamidase is a YAP/TAZ target gene that is important for cancer stem cell survival and for maintaining integrin expression. TG2 inhibition using NC9 dramatically reduces tumorigenicity 144, 145.

We are aware that many of these target proteins also act upstream and stimulate YAP/TAZ by forming a positive feedback but we would nevertheless consider them in this group and not as group I as their expression is influenced by the TEAD-binding motif and YAP/TAZ.

Although attractive, toxicity issues and the identification of responsive patient population could be challenges in the successful implementation of the YAP/TAZ inhibitors in the clinic. YAP/TAZ inhibition might elicit toxicity 146; homozygous disruption of YAP in mice causes embryonic lethality, whereas TAZ knockouts are viable 147-150. Tissue-specific deletions of YAP in the heart 151, lung 152 or kidney 153 cause hypoplasia, whereas YAP/TAZ deletion in the liver cause hepatomegaly and liver injury 154. Surprisingly, YAP/TAZ knockouts in the intestine are well tolerated with no apparent tissue defects 155. All of these suggest that YAP and TAZ are crucial for development. However, they appear to be dispensable for adult tissue homeostasis. In most adult tissues, under normal homeostasis, YAP/TAZ are found restricted to the cytoplasm and are activated primarily in response to injury to initiate tissue regeneration. Therefore, it is predictable that administration of a YAP/TAZ inhibitor may not elicit severe toxicity. However, given the dynamic shuttling of YAP/TAZ/Yorkie between nucleus and cytoplasm 156-158, it is feasible that they still have a role in normal tissue homeostasis. Fittingly, YAP has been identified to be important for podocyte homeostasis and its functional inactivation compromises the glomerular filtration barrier and cause renal disease 109. Along similar lines, renal toxicity was observed in mice administered with K-975 - a YAP/TAZ-TEAD inhibitor 127. Renal toxicity in targeted therapy is very common and is seen in most of the kinase inhibitors used in oncology 159. Yet these kinase inhibitors are in the clinic as there is a therapeutic window, where the drug could be dosed to improve patient survival without causing much toxicity. The same could be envisaged for YAP/TAZ-inhibiting drugs.

Several drugs that act as YAP/TAZ inhibitors target multiple signaling pathways. Targeting multiple pathways could be a boon or a bane. Drug resistance is minimized in a multi-targeted approach as potential bypass mechanisms are also targeted. However, toxicity becomes an issue when the drug targets multiple important signaling pathways. For instance, raising cAMP through the use of PDE inhibitors activates a multitude of proteins like PKA, EPACs, ion channels and small GTPases. Similarly, GPCR modulators influence multiple pathways through signaling via G proteins, arrestins or GPCR kinases. To reduce toxic side effects, there are options available like selective targeting or biased signaling. Instead of hitting all the PDEs, the PDE enzyme that is the most potent activator of YAP/TAZ should be selectively targeted. Nonspecific PDE inhibitors cause more severe side effects than sub-type selective PDE inhibitors 160. Similarly, through stabilizing a particular GPCR conformation, certain small molecule GPCR modulators are able to effect signaling bias where one GPCR effector is preferentially activated over others, say G proteins over -arrestins, this way only a subset of signaling pathways get activated 161.

Another major challenge is the identification of patients responding to a YAP/TAZ inhibitor. YAP/TAZ expression is low in normal tissues and their levels are significantly elevated in cancers. Is YAP or TAZ positivity in tumors sufficient criteria to administer a YAP/TAZ inhibitor? YAP and TAZ might not be transcriptionally active or drivers in all tumors. Further, they could be expressing target genes that negatively regulate their activity 162, 163. There are also tumor types where YAP/TAZ or TEAD levels have no prognostic significance 46. These YAP/TAZ positive tumors are unlikely to respond to a YAP/TAZ inhibitor. Barring a few such scenarios, in many solid tumors, YAP or TAZ expression levels correlate well with higher-grade cancers or poor prognosis. Tumors with nuclear YAP or TAZ that are also positive for the downstream oncogenic YAP/TAZ target genes are likely to respond to a YAP/TAZ inhibitor and this should be used as criteria for patient stratification. As many of the YAP/TAZ-TEAD target genes are secreted proteins, the expression levels of these in the serum could also be estimated in addition to assessing their levels through immunohistochemistry.

As YAP and TAZ contribute to the acquisition of many hallmarks of cancer traits, targeting them is predicted to be more relevant for the management of several cancer types. It is still early to expect a newly developed drug against YAP/TAZ but it is nevertheless disconcerting to see that there are hardly any clinical trials that evaluate if known drugs could be repurposed as YAP/TAZ- inhibitors. Group I drugs are well suited to repurpose 105 but only statins ({"type":"clinical-trial","attrs":{"text":"NCT03358017","term_id":"NCT03358017"}}NCT03358017); trametinib ({"type":"clinical-trial","attrs":{"text":"NCT03148275","term_id":"NCT03148275"}}NCT03148275) and epigenetic modulators ({"type":"clinical-trial","attrs":{"text":"NCT03925428","term_id":"NCT03925428"}}NCT03925428) are being evaluated in clinical trials, assessment of the expression levels of YAP/TAZ after drug treatment is used as one of the clinical trial objectives. It is essential that we bolster our pharmacological arsenal so that we are prepared to combat YAP and TAZ. Group I drugs that failed in oncology trials are not expected to fare any better against YAP/TAZ. However, drugs that are already in the clinic like the kinase inhibitors targeting the EGFR or MEK, PDE inhibitors as well as GPCR modulators could be repurposed to combat YAP/TAZ. The cancer types need to be carefully stratified to ensure they are driven by YAP/TAZ through the upstream stimulator targeted by the drug. To overcome potential bypass mechanism or drug resistance, combinatory use of group I and II drugs could also serve as an avenue for cancer treatment. For the group III drugs, the situation may not be as promising, as they target only one of the many possible oncogenic proteins regulated by YAP/TAZ. Again, combinatory inhibition of few downstream target genes could be considered if they are collectively essential for oncogenic manifestation of YAP/TAZ-driven transcription. As they are new and untested, there is much excitement and progress in the development of novel group II compounds as drugs against YAP/TAZ. We are at an exciting juncture in the Hippo field where we could potentially see a novel group II drug or a repurposed group I drug to combat YAP/TAZ in the near future.

A.V. Pobbati and W. Hong are supported by the Agency for Science, Technology, and Research (A*STAR), Singapore. We thank Sayan Chakraborty, Gandhi T.K.B. and John Hellicar for critical reading of this review. We apologize to all authors whose work was not cited due to space constraints.

See the original post here:
A combat with the YAP/TAZ-TEAD oncoproteins for cancer therapy

Spinal cord injuries can be devastating and there are currentlyfew options to reverse the effects, which can include paralysis, chronic pain and loss of bladder control.

But an international team of researchers, including the University of Torontos Molly Shoichet,hopes to change that.

Over the past few years, weve made a lot of progress in tissue engineering, drug delivery and regenerative medicine, says Shoichet, a University Professor in the department of chemical engineering and applied chemistry in the Faculty of Applied Science & Engineering, the Institute of Biomedical Engineering and the Donnelly Centre for Cellular and Biomolecular Research.

With this ambitious project, we bring world leading experts together to try to do something that no one else has been able to do: promote repair and regeneration in the injured spinal cord.

Shoichet is a co-principal investigator withMend the Gap, an international collaboration of more than 30 researchers, engineers, scientists, surgeons and social scientists from Canada, the United States, Europe and Australia. The collaboration this week received $24 million from Canadas New Frontiers in Research Fund to advance their work.

The team takes its name from the fact that only a small gap, just a few centimetres long, is responsible for blocking the nerve impulses that normally flow through the spinal cord. Bridging that gap requires collaboration from some of the worlds top experts in a wide range of fields.

Shoichet is known internationally for her work on hydrogels biocompatible materials that can help facilitate tissue repair. Hydrogels can function as scaffolds, enhancing or augmenting natural processes that serve to repair damaged tissue.

Hydrogels can also serve as controlled-release mechanisms for drugs that aid healing, or to protect stem cells that are being injected into the body bykeeping them alive and healthy while they integrate into damaged tissues.

Another important line of research involves dealing with the glial scar that forms in the wake of a spinal cord injury. In the short term, this protective shield of cells and biochemicals prevents further injury in the damaged nerve, but in the long termit can serve as a barrier to nerve repair.

Shoichet and her team bring their expertise in hydrogels and local delivery strategies to deliver innovative biomolecules locally and directly to the injured spinal cord. For example, shere-engineered an enzymeto selectively degrade some of the biomolecules that make up the glial scar. This redesigned enzyme is both more stable and more active than the wild type.

By breaking through the glial scar with this new delivery strategy, the enzyme can enable other therapies from advanced drugs to stem cells to further promote tissue regeneration and repair.

The environment in the injured spinal cord is a very complicated place, says Shoichet. There are a whole range of natural processes at work some of which we want to enhance, others of which we need to find ways to circumvent. I am very excited to be part of this multidisciplinary team, which has the breadth and depth of expertise that we need to make a real difference when it comes to treating spinal cord injury.

Shoichet is the only person to be elected a fellow of all three of Canadas national academiesand is a foreign member of the U.S. National Academy of Engineering and a fellow of the Royal Society of London. She was the 2020 recipient of the Gerhard Herzberg Canada Gold Medal, Canadas highest honour for science and engineering research. She is also a member of the Order of Ontario and an Officer of the Order of Canada.

Read more from the original source:
Mending the gap: U of T's Molly Shoichet joins team developing new treatments for spinal cord injuries - News@UofT

In many ways, the human body is like any other machine in that it requires constant refueling and maintenance to keep functioning. Much of this happens without our intervention beyond us selecting what to eat that day. There are however times when due to an accident, physical illness or aging the automatic repair mechanisms of our body become overwhelmed, fail to do their task correctly, or outright fall short in repairing damage.

Most of us know that lizards can regrow tails, some starfish regenerate into as many new starfish as the pieces which they were chopped into, and axolotl can regenerate limbs and even parts of their brain. Yet humans too have an amazing regenerating ability, although for us it is mostly contained within the liver, which can regenerate even when three-quarters are removed.

In the field of regenerative medicine, the goal is to either induce regeneration in damaged tissues, or to replace damaged organs and tissues with externally grown ones, using the patients own genetic material. This could offer us a future in which replacement organs are always available at demand, and many types of injuries are no longer permanent, including paralysis.

Our level of understanding of human physiology and that of animals in general has massively expanded since the beginning of the 20th century when technology allowed us to examine the microscopic world in more detail than ever before. Although empirical medical science saw its beginnings as early as the Sumerian civilization of the 3rd millennium BCE, our generalized understanding of the processes and components that underlie the bodys functioning are significantly more recent.

DNA was first isolated in 1869 by Friedrich Miescher, but its structure was not described until 1953. This discovery laid the foundations for the field of molecular biology, which seeks to understand the molecular basis for biological activity. In a sense this moment can be seen as transformative as for example the transition from classical mechanics to quantum mechanics, in that it changed the focus from macroscopic observations to a more fundamental understanding of these observations.

This allowed us to massively increase our understanding of how exactly the body responds to damage, and the molecular basis for regenerative processes, as well as why humans are normally not able to regrow damaged limbs. Eventually in 1999 the term regenerative medicine was coined by William A. Haseltine, who wrote an article in 2001 on what he envisions the term to include. This would be the addressing of not only injuries and trauma from accidents and disease, but also aging-related conditions, which would address the looming demographic crisis as the average age of the worlds populations keeps increasing.

The state of the art in regenerative medicine back in 2015 was covered by Angelo S. Mao et al. (2015). This covers regenerative methods involving either externally grown tissues and organs, or the stimulating of innate regenerative capabilities. Their paper includes the biomedical discipline of tissue engineering due to the broad overlap with the field of regenerative medicine. Despite the very significant time and monetary requirement to bring a regenerative medicine product to market, Mao et al. list the FDA-approved products at that time:

While these were not miracle products by any stretch of the imagination, they do prove the effectiveness of these approaches, displaying similar or better effectiveness as existing products. While getting cells to the affected area where they can induce repair is part of the strategy, another essential part involves the extracellular matrix (ECM). These are essential structures of many tissues and organs in the body which provide not only support, but also play a role in growth and regeneration.

ECM is however non-cellular, and as such is seen as a medical device. They play a role in e.g. the healing of skin to prevent scar tissue formation, but also in the scaffolding of that other tantalizing aspect of regenerative medicine: growing entire replacement organs and body parts in- or outside of the patients body using their own cells. As an example, Mase Jr, et al. (2010) report on a 19-year old US Marine who had part of his right thigh muscle destroyed by an explosion. Four months after an ECM extracted from porcine (pig) intestinal submucossa was implanted in the area, gradual regrowth of muscle tissue was detected.

An important research area here is the development of synthetic ECM-like scaffolding, as this would make the process faster, easier and more versatile. Synthetic scaffolding makes the process of growing larger structures in vitro significantly easier as well, which is what is required to enable growing organs such as kidneys, hearts and so on. These organs would then ideally be grown from induced pluropotent stem cells (iPS), which are a patients own cells that are reverted back to an earlier state of specialization.

It should come as little surprise that as a field which brings together virtually every field that touches upon (human) biology in some fashion, regenerative medicine is not an easy one. While its one thing to study a working system, its a whole different level to get one to grow from scratch. This is why as great as it would be to have an essentially infinite supply of replacement organs by simply growing new ones from iPS cells, the complexity of a functional organ makes this currently beyond our reach.

Essentially the rule is that the less complicated the organ or tissue is, the easier it is to grow it in vitro. Ideally it would just consist out of a single type of cell, and happy develop in some growth medium without the need for an ECM. Attractive targets here are for example the cornea, where the number of people on a waiting list for a corneal transplant outnumber donor corneas significantly.

In a review by Mobaraki et al. (2019), the numerous currently approved corneal replacements as well as new methods being studied are considered. Even though artificial corneas have been in use for years, they suffer from a variety of issues, including biocompatibility issues and others that prevent long-term function. Use of donor corneas comes with shortages as the primary concern. Current regenerative research focuses on the stem cells found in the limbus zone (limbal stem cells, LSC). These seem promising for repairing ocular surface defects, which has been studied since 1977.

LSCs play a role in the regular regenerative abilities of the cornea, and provide a starting point for either growing a replacement cornea, or to repair a damaged cornea, along with the addition of an ECM as necessary. This can be done in combination with the inhibiting of the local immune response, which promotes natural wound healing. Even so, there is still a lot more research that needs to be performed before viable treatments for either repairing the cornea in situ, or growing a replacement in vitro can be approved the FDA or national equivalent.

A similar scenario can be seen with the development of artificial skin, where fortunately due to the large availability of skin on a patients body grafts (autografts) are usually possible. Even so, the application of engineered skin substitutes (ESS) would seem to be superior. This approach does not require the removal of skin (epidermis) elsewhere, and limits the amount of scar formation. It involves placing a collagen-based ECM on the wound, which is optionally seeded with keritanocytes (skin precursor cells), which accelerates wound closure.

Here the scaffolding proved to be essential in the regeneration of the skin, as reported by Tzeranis et al. (2015). This supports the evidence from other studies that show the cell adhesion to the ECM to be essential in cell regulation and development. With recent changes, it would seem that both the formation of hair follicles and nerve innervation may be solved problems.

It will likely still be a long time before we can have something like a replacement heart grown from a patients own iPS cells. Recent research has focused mostly on decellularization (leaving only the ECM) of an existing heart, and repopulating it with native cells (e.g. Glvez-Montn et al., 2012). By for example creating a synthetic scaffold and populating it with cells derived from a patients iPS cells, a viable treatment could be devised.

Possibly easier to translate into a standard treatment is the regrowth of nerves in the spinal cord after trauma, with a recent article by lvarez et al, (2021) (press release) covering recent advances in the use of artificial scaffolds that promotes nerve regeneration, reduces scarring and promotes blood vessel formation. This offers hope that one day spinal cord injures may be fully repairable.

If we were to return to the body as a machine comparison, then the human body is less of a car or piece of heavy machinery, and more of a glued-together gadget with complex circuitry and components inside. With this jump in complexity comes the need for a deeper level of understanding, and increasingly more advanced tools so that repairs can be made efficiently and with good outcomes.

Even so, regenerative medicine is already saving the lives of for example burn victims today, and improving the lives of countless others. As further advances in research continue to translate into treatments, we should see a gradual change from youll have to learn to live with that, to a more optimistic give it some time to grow back, as in the case of an injured veteran, or the victim of an accident.

Go here to see the original:
Regenerative Medicine: The Promise Of Undoing The Ravages Of Time - Hackaday

After the therapy performs its function, the materials biodegrade into nutrients for the cells within 12 weeks and then completely disappear from the body without noticeable side effects.This is the first study in which researchers controlled the collective motion of molecules through changes in chemical structure to increase a therapeutics efficacy.

Samuel I. Stupp

Our research aims to find a therapy that can prevent individuals from becoming paralyzed after major trauma or disease, said NorthwesternsSamuel I. Stupp, who led the study. For decades, this has remained a major challenge for scientists because our bodys central nervous system, which includes the brain and spinal cord, does not have any significant capacity to repair itself after injury or after the onset of a degenerative disease. We are going straight to the FDA to start the process of getting this new therapy approved for use in human patients, who currently have very few treatment options.

Stupp is Board of Trustees Professor of Materials Science and Engineering, Chemistry, Medicine and Biomedical Engineering at Northwestern, where he is founding director of theSimpson Querrey Institute for BioNanotechnology(SQI) and its affiliated research center, theCenter for Regenerative Nanomedicine. He has appointments in theMcCormick School of Engineering,Weinberg College of Arts and SciencesandFeinberg School of Medicine.

According to the National Spinal Cord Injury Statistical Center, nearly 300,000 people are currently living with a spinal cord injury in the United States. Life for these patients can be extraordinarily difficult. Less than 3% of people with complete injury ever recover basic physical functions. And approximately 30% are re-hospitalized at least once during any given year after the initial injury, costing millions of dollars in average lifetime health care costs per patient. Life expectancy for people with spinal cord injuries is significantly lower than people without spinal cord injuries and has not improved since the 1980s.

I wanted to make a difference on the outcomes of spinal cord injury and to tackle this problem, given the tremendous impact it could have on the lives of patients.

Currently, there are no therapeutics that trigger spinal cord regeneration, said Stupp, an expert in regenerative medicine. I wanted to make a difference on the outcomes of spinal cord injury and to tackle this problem, given the tremendous impact it could have on the lives of patients. Also, new science to address spinal cord injury could have impact on strategies for neurodegenerative diseases and stroke.

A new injectable therapy forms nanofibers with two different bioactive signals (green and orange) that communicate with cells to initiate repair of the injured spinal cord. Illustration by Mark Seniw

The secret behind Stupps new breakthrough therapeutic is tuning the motion of molecules, so they can find and properly engage constantly moving cellular receptors. Injected as a liquid, the therapy immediately gels into a complex network of nanofibers that mimic the extracellular matrix of the spinal cord. By matching the matrixs structure, mimicking the motion of biological molecules and incorporating signals for receptors, the synthetic materials are able to communicate with cells.

Receptors in neurons and other cells constantly move around, Stupp said. The key innovation in our research, which has never been done before, is to control the collective motion of more than 100,000 molecules within our nanofibers. By making the molecules move, dance or even leap temporarily out of these structures, known as supramolecular polymers, they are able to connect more effectively with receptors.

100,000molecules move within the nanofibers

Stupp and his team found that fine-tuning the molecules motion within the nanofiber network to make them more agile resulted in greater therapeutic efficacy in paralyzed mice. They also confirmed that formulations of their therapy with enhanced molecular motion performed better during in vitro tests with human cells, indicating increased bioactivity and cellular signaling.

Given that cells themselves and their receptors are in constant motion, you can imagine that molecules moving more rapidly would encounter these receptors more often, Stupp said. If the molecules are sluggish and not as social, they may never come into contact with the cells.

Once connected to the receptors, the moving molecules trigger two cascading signals, both of which are critical to spinal cord repair. One signal prompts the long tails of neurons in the spinal cord, called axons, to regenerate. Similar to electrical cables, axons send signals between the brain and the rest of the body. Severing or damaging axons can result in the loss of feeling in the body or even paralysis. Repairing axons, on the other hand, increases communication between the body and brain.

Zaida lvarez

The second signal helps neurons survive after injury because it causes other cell types to proliferate, promoting the regrowth of lost blood vessels that feed neurons and critical cells for tissue repair. The therapy also induces myelin to rebuild around axons and reduces glial scarring, which acts as a physical barrier that prevents the spinal cord from healing.

The signals used in the study mimic the natural proteins that are needed to induce the desired biological responses. However, proteins have extremely short half-lives and are expensive to produce, said Zaida lvarez, the studys first author. Our synthetic signals are short, modified peptides that when bonded together by the thousands will survive for weeks to deliver bioactivity. The end result is a therapy that is less expensive to produce and lasts much longer.

A former research assistant professor in Stupps laboratory,lvarez is now a visiting scholar at SQI and a researcher at theInstitute for Bioengineering of Catalonain Spain.

While the new therapy could be used to prevent paralysis after major trauma (automobile accidents, falls, sports accidents and gunshot wounds) as well as from diseases, Stupp believes the underlying discovery that supramolecular motion is a key factor in bioactivity can be applied to other therapies and targets.

The central nervous system tissues we have successfully regenerated in the injured spinal cord are similar to those in the brain affected by stroke and neurodegenerative diseases, such as ALS, Parkinsons disease and Alzheimers disease, Stupp said. Beyond that, our fundamental discovery about controlling the motion of molecular assemblies to enhance cell signaling could be applied universally across biomedical targets.

View post:
Dancing molecules successfully repair severe spinal cord ...

Sharing is caring!

Cardiac muscle cells or cardiomyocytes (also known as cardiac myocytes) are the muscle cells (myocytes) that make up the heart muscle. Cardiomyocytes go through a contraction-relaxation cycle that enables cardiac muscles to pump blood throughout the body.

[In this image] Immunostaining of human cardiomyocytes with antibodies for actin (red), myomesin (green), and nuclei (blue).Photo source: https://www.fujifilmcdi.com/products/cardiac-cells/icell-cardiomyocytes

Cardiomyocytes are highly specialized cell types in terms of their structures and functions. Each cardiomyocyte contains myofibrils, unique organelles consisting of long chains of sarcomeres, the fundamental contractile units of muscle cells.

[In this image] Cardiomyocyte geometry and cellular architecture are controlled by micropatterned ECM substrate. Scientists used this technique to study how cells sense and respond to mechanical forces.Photo source: https://diseasebiophysics.seas.harvard.edu/research/mechanotransduction/

The heart is a muscular organ that pumps blood through the blood vessels of the circulatory system. It is composed of individual heart muscle cells (cardiomyocytes) and several other cell types.

[In this figure] The anatomy of the human heart showing 4 heart chambers (left atrium, left ventricle, right atrium, right ventricle) and the blood flow. The myocardium is referred to the cardiac muscle layers building the wall of each chamber.

[In this figure] The thickness of the heart wall (or myocardium) consists of cardiac muscle cells.Photo source: biologydictionary

[In this video] Structure of the human heart.

Cardiovascular disease is a leading cause of death worldwide. Nearly 2,400 Americans die of cardiac causes each day, one death every 37 seconds.

As the chief cell type of the heart, cardiac muscle cells primarily dedicate to the contractile function of the heart and enable the pumping of blood around the body. If anything goes wrong in the heart, it can lead to a catastrophic outcome. A myocardial infarction (MI), commonly known as a heart attack, occurs when blood flow ceases to a part of the heart, causing massive cardiomyocyte death in that area. Severe cases can, ultimately, lead to heart failure and death.

[In this figure] The progress of myocardial infarction or heart attack. At time post-infarction:

0-12 hours: Beginning of necrotic coagulation due to the blockage of coronary arteries Cardiomyocytes suffer the lack of oxygen (hypoxia)

12-72 hours: Culmination of necrotic coagulation Neutrophils infiltrate by an inflammatory response.

1-3 weeks: Disintegration of death myocytes and formation of granulation tissue (collagenous fibers, macrophages, and fibroblasts)

> 1 month: Formation of fibrous scar (fewer cells with an abundance of collagenous fibers)

A human heart contains an estimated 23 billion cardiomyocytes. There are several non-myocyte populations in the heart, including endothelial cells, smooth muscle cells, myofibroblasts, epicardial cells, endocardial cells, valve interstitial cells, resident macrophages, and other immune system-related cells, and potentially, adult stem cells (mesenchymal stem cells and cardiac stem cells). These distinct cell pools are not isolated from one another within the heart but interact physically to maintain the function of the whole organ. Overall, cardiomyocytes only account for less than a third of the total cell number in the heart.

[In this image] Immunostaining showing highly vascularized heart muscle.Cardiomyocytes are labeled by the striated pattern of sarcomeric -actinin (green). Capillaries are red and nuclei are blue.Photo source: biocompare.

The three main types of muscle include: Cardiac muscle, Skeletal muscle, and Smooth muscle.

[In this figure] Morphology and comparison of cardiac, skeleton, and smooth muscles.

Note: Involuntary muscles are the muscles that cannot be controlled by will or conscious.

There are two types of cells within the heart: the cardiomyocytes and the cardiac pacemaker cells.

The heart is composed of cardiac muscle cells that have specialized features that relate to their function:

These structural features contribute to the unique functional properties of the cardiac tissue:

Like other animal cells, cardiomyocytes contain all the cell organelles that are essential for normal cell physiology. Moreover, cardiomyocytes have several unique cellular structures that allow them to perform their function effectively. Here are five main characteristics of mature cardiomyocytes: (1) striated; (2) uninucleated; (3) branched; (4) connected by intercalated discs; (5) high mitochondrial content.

[In this figure] Main characteristics of cardiac myocytes.Modified from lumen Anatomy and Physiology I.

Lets get closer to look inside a cardiomyocyte and learn its unique ultrastructure.

All cardiomyocytes and pacemaker cells are linked by cellular bridges. Intercalated discs, which form porous junctions, bring the membranes of adjacent cardiomyocytes very close together. These pores (gap junctions) permit ions, such as sodium, potassium, and calcium, to easily diffuse from cell to cell, establishing a cell-cell communication. This joining is called electric coupling, and it allows the quick transmission of action potentials and the coordinated contraction of the entire heart.

Intercalated discs also function as mechanical anchor points that enable the transmission of contractile force from one cardiomyocyte to another (by desmosomes and adherens junctions). This allows for the heart to work as a single coordinated unit.

[In this figure] Cardiac muscle cells are connected together to coordinate the cardiac contraction. This joining is called electric coupling and is achieved by the presence of irregularly-spaced dark bands between cardiomyocytes. These bands are known as intercalated discs.Photo source: bioninja.

[In this figure] Cardiac myocytes are branched and interconnected from end to end by structures called intercalated disks, visible as dark lines in the light microscope.Photo source: https://doctorlib.info/physiology/medical/49.html

There are 3 main types of junctional complexes within the intercalated discs. They work in different ways to maintain cardiac tissue integrity and cardiomyocyte synchrony.

The term desmosome came from Greek words of bonding (desmo) and body (soma). Desmosomes serve as the anchor points to bring the cardiac muscle fibers together. Desmosomes can withstand mechanical stress, which allows them to hold cells together. Without desmosomes, the cells of the cardiac muscles will fall apart during contraction.

The ability of desmosome to resist mechanical stress comes from its unique 3-D structure. Desmosome is an asymmetrical protein complex bridging between two adjacent cardiomyocytes, with each end residing in the cytoplasm. The intracellular part anchors intermediate filaments in the cytoskeleton to the cell surface. The middle part bridges the intercellular space between two cytoplasmic membranes.

[In this figure] Desmosomes connect intermediate filaments from two adjust cardiomyocytes. This job is accomplished by the formation of a dense protein complex or plaque in the intercalated discs. Major protein players include transmembrane cadherins: desmogleins (Dsgs) and desmocollins (Dscs), cytoplasmic anchors: plakophilins (PKPs) and plakoglobin (PG), and cytoskeleton adaptor: desmoplakin (DP). Cadherins link cells together, and other proteins form a dense complex called plaque.

In addition to desmosomes, adherens junctions (Ajs) are another type of mechanical intercellular junctions in cardiomyocytes. The difference is that adherens junctions link the intercalated disc to the actin cytoskeleton and desmosomes attach to intermediate filaments.

Adherens junctions keep the cardiac muscle cells tightly together as the heart pump. Adherens junctions are also the anchor point where myofibrils are attached, enabling transmission of contractile force from one cell to another.

[In this figure] Adherens junctions link actin cytoskeleton from two adjust cardiomyocytes together.Adherens junctions are constructed from cadherins and catenins. Cadherins (in cardiomyocytes N-Cadherin is the main cadherin) are transmembrane proteins that zip together adjacent cells in a homophilic manner. The transmembrane cadherins form complexes with cytosolic catenins, thereby establishing the connection to the actin cytoskeleton. At the adherens junctions, the opposing membranes become separated by 20nm.

Gap junctions are essential for the chemical and electrical coupling of neighboring cells. Gap junctions work like intercellular channels connecting the cytoplasm of neighboring cells, enabling passive diffusion of various compounds, like metabolites, water, and ions, up to a molecular mass of 1000 Da. Thereby they establish direct communication between adjacent cells.

[In this figure] Neonatal rat cardiac myocytes in cell culture.Cells were immunostained for actinin (green), gap junctions (red), and counterstained with DAPI (blue).Photo source: bioscience

Gap junctions are present in nearly all tissues and cells throughout the entire body. In cardiac muscle, gap junctions ensure proper propagation of the electrical impulse (from pacemaker cells to neighboring cardiomyocytes). This electrical wave triggers sequential and coordinated contraction of the cardiomyocytes as a whole.

[In this figure] A gap junction channel consists of twelve connexin proteins, six of which are contributed by each cell. The six connexin subunits form a hemi-channel in the plasma membrane, which is called a connexon. A connexon docks to another connexon in the intercellular space to create a complete gap junction channel. The intercellular space between adjacent cells at the site of a gap junction is 2-4 nm.

A second feature of cardiomyocytes is the sarcomeres, which are also present in skeletal muscles. The sarcomeres give cardiac muscle their striated appearance and are the repeating sections that make up myofibrils.

[In this image] Freshly isolated heart muscle cells showing intercalated discs (green), sarcomeres (red), and nuclei (blue).Photo source: https://christianz.artstation.com/

Cardiac muscle cells are equipped with bundles of myofibrils that contain myofilaments. These fiber-like structures can occupy 45-60% of the volume of cardiomyocytes. The myofibrils are formed of distinct, repeating units, termed sarcomeres. The sarcomeres, which are composed of thick and thin myofilaments, represent the basic contractile units of a muscle cell and are defined as the region of myofilament structures between two Z-lines (see image below). The distance between Z-lines in human hearts ranges from around 1.6 to 2.2 m.

[In this figure] Labeled diagram of myofibril showing the unit of a sarcomere. A sarcomere is defined as a segment between two neighboring Z-discs.

[In this image] Immunofluorescence image of adult mouse cardiomyocytes showing the Z-lines of the sarcomeres. 3D color projection of alpha-actinin 2 acquired with a confocal microscope.Photo source: Dylan Burnette.

The thick filaments are composed of myosin II. Each myosin contains two ATPase sites on its head. ATPase hydrolyzes ATP and this process is required for actin and myosin cross-bridge formation. These heads bind to actin on the thin filaments. There are about 300 molecules of myosin per thick filament.

The thin filaments are composed of single units of actin known as globular actin (G-actin). Two strands of actin filaments form a helix, which is stabilized by rod-shaped proteins termed tropomyosin. Troponin proteins, which function as regulators, bind to the tropomyosin at regular intervals. Whereas troponin lies in the grooves between the actin filaments, tropomyosin covers the sites on which actin binds to myosin. Their respective actions, therefore, control the binding of myosin to actin and consequently in the contraction and relaxation of cardiac muscles.

To generate muscular contraction, the myosin heads bind to actin filaments, allowing myosin to function as a motor that drives filament sliding. The actin filaments slide past the myosin filaments toward the middle of the sarcomere. This results in the shortening of the sarcomere without any change in filament length.

[In this figure] Sliding-filament model of muscle contraction.

Sarcolemma (also called myolemma) is a specialized cell membrane of cardiomyocytes and skeletal muscle cells. It consists of a lipid bilayer and a thin outer coat of polysaccharide material (glycocalyx) that contacts the basement membrane. The sarcolemma is also part of the intercalated disks as well as the T-tubules of the cardiac muscle.

Basement membrane is an extracellular matrix (ECM) coat that cover individual cardiomyocytes. Its composed of glycoproteins laminin and fibronectin, type IV collagen as well as proteoglycans that contribute to its overall width of about 50nm. Basement membrane provides a scaffold to which the muscle fiber can adhere.

[In this figure] A cross-section of a mouse heart showing the basement membrane (green) wrapping around an individual myocyte.

In cardiomyocytes and skeletal muscle cells, the sarcolemma (i.e. the plasma membrane) forms deep invaginations known as T-tubules (or transverse tubules). These invaginations increase the total surface area and allow depolarization of the membrane to penetrate quickly to the interior of the cell.

Without t-tubules, the wave of calcium ions (Ca2+) takes time to propagate from the periphery of the cell into the center. This time lag will first activate the peripheral sarcomeres and then the deeper sarcomeres, resulting in sub-maximal force production.

The t-tubules make it possible that current is simultaneously relayed to the core of the cell, and trigger near to all sarcomeres simultaneously, resulting in a maximal force output. T-tubules also stay close to sarcoplasmic reticulum (SR) networks, which is the modified endoplasmic reticulum (ER) of calcium storage in myocytes.

[In this figure] T-tubules (transverse tubules) are extensions of the cell membrane that penetrate into the center of skeletal and cardiac muscle cells. T-tubules permit the rapid transmission of the action potential into the cell and also play an important role in regulating cellular calcium concentration.

Mitochondria are the powerhouse of the cell because they generate most of the cells energy supply of adenosine triphosphate (ATP). It is no doubt that the normal functions of cardiomyocytes require a lot of energy. Effective heart pumping is primarily dependent on oxidative energy production by mitochondria. Cardiomyocytes have a densely packed mitochondrial network, which allows them to produce ATP quickly, making them highly resistant to fatigue.

Different types of mitochondria can be distinguished within cardiomyocytes, and their morphological features are usually defined according to their location: intermyofibrillar mitochondria, subsarcolemmal mitochondria, and perinuclear mitochondria.

[In this figure] Mitochondrial morphology in cardiomyocytes.(Top) The anatomy of a mitochondrion. (Bottom left) Schematic diagram of the location of subsarcolemmal mitochondria (SSM), interfibrillar mitochondria (IFM), and perinuclear mitochondria (PNM). (Bottom right) TEM images of mitochondria in cardiomyocytes.Photo source: researchgate, wiki

Intermyofibrilar Mitochondria are found deeper within the cells and strictly ordered between rows of contractile proteins, apparently isolated from each other by repeated arrays. They play a huge role in producing enough energy for muscle contractions.

[In this figure] Immunofluorescent confocal imaging showing the densely packed mitochondria in cardiomyocytes. (A): Z-line (actinin); (B): Mitochondria; (C): Merge image.Photo source: MDPI

Subsarcolemmal Mitochondria reside beneath the sarcolemma. They collect oxygen from the circulating blood in the arteries and are responsible for providing the energy needed for conserving the integrity of the sarcolemma.

Perinuclear mitochondria are organized in clusters around the nucleus to provide energy for transcription and translation processes.

The cardiac function requires high energy demands; therefore, the adult cardiomyocytes contain numerous mitochondria, which can occupy at least 30% of cell volume. They meet >90% of the energy requirements by oxidative phosphorylation (OXPHOS) in the mitochondria, which requires a huge demand for oxygen consumption.

In humans, at a heart rate of 6070 beats per minute, the oxygen consumption of the myocardium is 20-fold higher than that of skeletal muscle at rest (compared by a normalization per gram of cell mass). In order to meet this high oxygen demand, the capillary density in the heart is 2-8 times higher than that in skeletal muscle (3,0004,000/mm2 compared to 5002,000 capillaries/mm2, respectively). Also, cardiomyocytes maintain a very high level of oxygen extraction (from blood) of 7080% compared with 3040% in skeletal muscle.

[In this image] Myofibrils in cultured cardiomyocytes.Photo source: https://christianz.artstation.com/

Cardiomyocytes go through a contraction-relaxation cycle that enables cardiac muscles to pump blood throughout the body. This is achieved through a process known as excitation-contraction coupling (ECC) that converts action potential (an electric stimulus) into muscle contraction.

[In this figure] Schematic diagram of the process of cardiac excitation-contraction coupling.Key steps in the cardiac excitation-contraction coupling:

Step 1: An action potential is induced by pacemaker cells. It travels along the sarcolemma and down into the T-tubule system to depolarize the cell membrane.

Step 2: Calcium channels in the T-tubules are activated by the action potential and permit calcium entry into the cell.

Step 3: Calcium influx triggers a subsequent release of calcium that is stored in the sarcoplasmic reticulum (SR).

Step 4: Free calcium binds troponin-C (TN-C) that is part of the regulatory complex attached to the thin filaments. Calcium binding moves the troponin complex from the actin binding site. As a result, actin is free to bind myosin. The actin and myosin filaments slide past each other thereby shortening the sarcomere length, thus initiating contraction.

Step 5: At the end of a contraction, calcium entry into the cell slows and calcium is sequestered by the SR by calcium pumps. Lowering the cytosolic calcium concentration releases myosin-actin binding and the initial sarcomere length is restored.

In human beings (and many other animals), cardiomyocytes are the first cells to terminally differentiate, thus making the heart one of the first organs to form in a developing fetus. This makes sense because the function of the circulatory system is so crucial for a growing embryo so that the heart is the top priority.

In the embryo of a mouse, for instance, precursor cells of the cardiac muscles have been shown to start developing about 6 days after fertilization. In human embryos, the heart begins to beat at about 22-23 days, with blood flow beginning in the 4th week. The heart is therefore one of the earliest differentiating and functioning organs.

The heart forms initially in the embryonic disc as a simple paired tube (heart tube formation; week 3) derived from mesoderm. Then, the heart tubes loop and begin segmenting to separate chambers primitive atrium, and primitive ventricle. During this period, the first heartbeat begins.

[In this figure] The timeline of heart development.LA means left atrium; RA means right atrium. For more details, seehttps://embryology.med.unsw.edu.au/embryology/index.php/Cardiovascular_System_-_Heart_Development

Here, cardiomyocytes grow into a spongy-like tissue (cardiac jelly), called trabeculation, to build up the thickness of myocardial muscles. Thus, the heart begins to resemble the adult heart in that it has two atria, two ventricles, and the aorta forming a connection with the left ventricle while the pulmonary trunk forms a connection with the right ventricle.

As you can see that our hearts went through a complex developmental process. Inevitably, heart developmental abnormalities could happen (affect 8-10 of every 1000 births in the United States).

Can cardiomyocytes divide? Scientists used to believe that damaged human cardiac muscles cannot regenerate themselves by cell division in adults. In other words, all cardiomyocytes are terminally differentiated. In humans, our cardiomyocytes lose the ability to divide at around 7 days after birth. However, studies have recently shown that myocytes renew at a significantly low rate throughout the life of an individual. For instance, for younger people, about 25 years of age, the annual turnover of cardiomyocytes is about 1 percent. This, however, decreases to about 0.45 percent for older individuals (75 and above). Over the lifespan of an individual, less than 50 percent of these cells are renewed. Comparing to many of the other cells, cardiomyocytes have a very long lifespan. In contrast, small intestine epithelium renews every 2-7 days and hepatocytes (liver cells) renew every 0.5-1 year.

[In this figure] Radiocarbon dating establishes the age of human cardiomyocytes.Scientists used a pretty smart way to estimate the turnover of human heart cells. Generally speaking, the half-life of 14C is too long to date a lifetime of less than a century. However, the dramatic increase in the atmospheric 14C caused by nuclear bomb tests (during the Cool War) in the 1950s and 1960s increased the sensitivity of radiocarbon dating to a temporal resolution of 1-2years.Photo source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5837331/

Low turnover of human cardiomyocytes suggests that the regenerative ability of cardiac muscles may be poor (another example is neural cells in the brain). In the event of injuries or myocardial infarction, the injured heart muscles of human beings do not regenerate sufficiently to allow the heart to heal itself. Instead, fibrotic scar tissue forms in the injured site (fibrosis), and the heart functions are compromised, leading to heart failure.

Currently, a number of methods have been studied to repair a broken heart by regenerating cardiomyocytes. These new inventions benefit from the recent advances in biotechnology, especially stem cell biology, regenerative medicine, and tissue engineering. Hopefully, this can bring new therapeutic options to patients with cardiovascular diseases in the near future.

Studies suggested that even in adults, a very small population of progenitor cells reside in the heart and are capable of producing new cardiac myocytes. These cells, known as cardiac stem cells, may not be able to regenerate fast enough to repair a large area of damaged myocardium naturally in humans. However, these cells have shown to be powerful in regenerative capability in other species, like zebrafish.

Scientists believe that once we understand these cardiac progenitors more, we may isolate and expand these cells in quantity, and transplant them to repair damaged heart tissues. For example, we already learned that these cardiac stem cells express cell surface markers like c-Kit (sca-1 in mouse) and aggregate into cardiac spheres.

[In this figure] Multiple different stem cell populations have been described in the adult heart, including c-Kit and Sca-1 cells that were shown to be cardiac progenitors.Photo source: https://dev.biologists.org/content/143/8/1242

Induced pluripotent stem cell (iPSC) technology is a huge revolution in biotechnology. Patients cells (easily obtained from skin biopsy or even urine) can be converted into powerful pluripotent stem cells that have unlimited proliferation capacity and can differentiate any cell type of our body. This eliminates the need to use human embryos for this purpose. Furthermore, these cells are autologous, meaning they wont be rejected by the immune system after transplantation.

Using iPSC technology, researchers have been able to obtain unlimited amounts of functional cardiomyocytes for cell transplantation. Basically, they control the Wnt pathway to convert iPSCs to mesodermal progenitor cells, then play with several growth factors to direct the cardiac vascular progenitors (Flk1+). Following glucose starvation, pure cardiomyocytes can be selected. You can even see these cells beating in the dish.

Therapeutic implantation of iPSC-derived cardiomyocytes progresses pretty fast. We already witnessed successful cell engraftment and cardiac repairing in non-human primates and human patients.

[In this video] Heart cells derived from iPSC stem cells beating in a cell culture dish.

Cardiac fibroblasts make up a significant portion of the total cardiac cells. In the injured heart, these fibroblasts will become active myofibroblasts and form scar tissue. Myofibroblasts survive very well and have ability to coupled with neighboring cells; therefore, myofibroblasts have been shown to be particularly ideal for direct reprogramming to convert them into cells that resemble cardiomyocytes.

Over the past decade, a number of studies have been successfully conducted, reprogramming fibroblasts into cardiomyocyte-like cells. In principle, scientists expressed transcription factors (i.e., Gata4, Mef2c, and Tbx5) that play critical roles in cardiomyocyte differentiation to force the conversion of fibroblasts. Ideally, these genes can be delivered directly to the injured heart via viruses or nanoparticles to perform in situ reprogramming.

Scientists also put their efforts into how to stimulate mature cardiomyocytes to proliferate again (Mature cardiomyocytes typically do not proliferate.) This strategy, called cell cycle re-entry, recently gained success by screening many cell-cycle regulators. Scientists found a combination of cyclin-dependent kinases (CDK) and cyclins, or regulators of the Hippo-YAP signaling pathway can do so. These findings reveal the possibility to efficiently unlock the proliferative potential in cells that had terminally exited the cell cycle.

[In this figure] Potential cardiac regenerative therapies.Photo source: https://www.nature.com/articles/s41536-017-0024-1

Cardiomyocytes can be observed by staining of histological sections of the heart. Since the heart is a 3-D organ, make sure you cut the heart at the right angle.

[In this figure] (Left) A longitudinal section through both ventricles should be made from the base to the apex of the heart. (Right) A cross-section of the heart. H&E staining.(Ao: aorta, At: atrium, Lv: left ventricle, Rv: right ventricle)

Common histological staining for heart tissues includes Hematoxylin and eosin (H&E) and Massons trichrome staining.

[In this figure] A cross section of mouse heart stained by Massons trichrome. Blue color indicates the formation of fibrous scar tissues in the infarction area.

Read more from the original source:
Cardiomyocytes (Cardiac Muscle Cells) - Structure ...

Introduction

Given the multi-lineage differentiation abilities of mesenchymal stem cells (MSCs) isolated from different tissues and organs, MSCs have been widely used in various medical fields, particularly regenerative medicine.13 The representative sources of MSCs are bone marrow, adipose, periodontal, muscle, and umbilical cord blood.410 Interestingly, slight differences have been reported in the characteristics of MSCs depending on the different sources, including their population in source tissues, immunosuppressive activities, proliferation, and resistance to cellular aging.11 Bone marrow-derived MSCs (BM-MSCs) are the most intensively studied and show clinically promising results for cartilage and bone regeneration.11 However, the isolation procedures for BM-MSCs are complicated because bone marrow contains a relatively small fraction of MSCs (0.0010.01% of the cells in bone marrow).12 Furthermore, bone marrow aspiration to harvest MSCs in human bones is a painful procedure and the slower proliferation rate of BM-MSCs is a clinical limitation.13 In comparison with BM-MSCs, adipose-derived MSCs (AD-MSCs) are relatively easy to collect and can produce up to 500 times the cell population of BM-MSCs.14 AD-MSCs showed a greater ability to regenerate damaged cartilage and bone tissues with increased immunosuppressive ability.14,15 Umbilical cord blood-derived MSCs (UC-MSCs) proliferate faster than BM-MSCs and are resistant to significant cellular aging.11

MSCs have been investigated and gained worldwide attention as potential therapeutic candidates for incurable diseases such as arthritis, spinal cord injury, and cardiac disease.3,1623 In particular, the inherent tropism of MSCs to inflammatory sites has been thoroughly studied.24 This inherent tropism, also known as homing ability, originates from the recognition of various chemokine sources in inflamed tissues, where profiled chemokines are continuously secreted and the MSCs migrate to the chemokines in a concentration-dependent manner.24 Rheumatoid arthritis (RA) is a representative inflammatory disease that primarily causes inflammation in the joints, and this long-term autoimmune disorder causes worsening pain and stiffness following rest. RA affects approximately 24.5 million people as of 2015, but only symptomatic treatments such as pain medications, steroids, and nonsteroidal anti-inflammatory drugs (NSAIDs), or slow-acting drugs that inhibit the rapid progression of RA, such as disease-modifying antirheumatic drugs (DMARDs) are currently available. However, RA drugs have adverse side effects, including hepatitis, osteoporosis, skeletal fracture, steroid-induced arthroplasty, Cushings syndrome, gastrointestinal (GI) intolerance, and bleeding.2527 Thus, MSCs are rapidly emerging as the next generation of arthritis treatment because they not only recognize and migrate toward chemokines secreted in the inflamed joints but also regulate inflammatory progress and repair damaged cells.28

However, MSCs are associated with many challenges that need to be overcome before they can be used in clinical settings.2931 One of the main challenges is the selective accumulation of systemically administered MSCs in the lungs and liver when they are administered intravenously, leading to insufficient concentrations of MSCs in the target tissues.32,33 In addition, most of the administered MSCs are typically initially captured by macrophages in the lungs, liver, and spleen.3234 Importantly, the viability and migration ability of MSCs injected in vivo differed from results previously reported as favorable therapeutic effects and migration efficiency in vitro.35

To improve the delivery of MSCs, researchers have focused on chemokines, which are responsible for MSCs ability to move.36 The chemokine receptors are the key proteins on MSCs that recognize chemokines, and genetic engineering of MSCs to overexpress the chemokine receptor can improve the homing ability, thus enhancing their therapeutic efficacy.37 Genetic engineering is a convenient tool for modifying native or non-native genes, and several technologies for genetic engineering exist, including genome editing, gene knockdown, and replacement with various vectors.38,39 However, safety issues that prevent clinical use persist, for example, genome integration, off-target effects, and induction of immune response.40 In this regard, MSC mimicking nanoencapsulations can be an alternative strategy for maintaining the homing ability of MSCs and overcoming the current safety issues.4143 Nanoencapsulation involves entrapping the core nanoparticles of solids or liquids within nanometer-sized capsules of secondary materials.44

MSC mimicking nanoencapsulation uses the MSC membrane fraction as the capsule and targeting molecules, that is chemokine receptors, with several types of nanoparticles, as the core.45,46 MSC mimicking nanoencapsulation consists of MSC membrane-coated nanoparticles, MSC-derived artificial ectosomes, and MSC membrane-fused liposomes. Nano drug delivery is an emerging field that has attracted significant interest due to its unique characteristics and paved the way for several unique applications that might solve many problems in medicine. In particular, the nanoscale size of nanoparticles (NPs) enhances cellular uptake and can optimize intracellular pathways due to their intrinsic physicochemical properties, and can therefore increase drug delivery to target tissues.47,48 However, the inherent targeting ability resulting from the physicochemical properties of NPs is not enough to target specific tissues or damaged tissues, and additional studies on additional ligands that can bind to surface receptors on target cells or tissues have been performed to improve the targeting ability of NPs.49 Likewise, nanoencapsulation with cell membranes with targeting molecules and encapsulation of the core NPs with cell membranes confer the targeting ability of the source cell to the NPs.50,51 Thus, MSC mimicking nanoencapsulation can mimic the superior targeting ability of MSCs and confer the advantages of each core NP. In addition, MSC mimicking nanoencapsulations have improved circulation time and camouflaging from phagocytes.52

This review discusses the mechanism of MSC migration to inflammatory sites, addresses the potential strategy for improving the tropism of MSCs using genetic engineering, and discusses the promising therapeutic agent, MSC mimicking nanoencapsulations.

The MSC migration mechanism can be exploited for diverse clinical applications.53 The MSC migration mechanism can be divided into five stages: rolling by selectin, activation of MSCs by chemokines, stopping cell rolling by integrin, transcellular migration, and migration to the damaged site (Figure 1).54,55 Chemokines are secreted naturally by various cells such as tumor cells, stromal cells, and inflammatory cells, maintaining high chemokine concentrations in target cells at the target tissue and inducing signal cascades.5658 Likewise, MSCs express a variety of chemokine receptors, allowing them to migrate and be used as new targeting vectors.5961 MSC migration accelerates depending on the concentration of chemokines, which are the most important factors in the stem cell homing mechanism.62,63 Chemokines consist of various cytokine subfamilies that are closely associated with the migration of immune cells. Chemokines are divided into four classes based on the locations of the two cysteine (C) residues: CC-chemokines, CXC-chemokine, C-chemokine, and CX3 Chemokine.64,65 Each chemokine binds to various MSC receptors and the binding induces a chemokine signaling cascade (Table 1).56,66

Table 1 Chemokine and Chemokine Receptors for Different Chemokine Families

Figure 1 Representation of stem cell homing mechanism.

The mechanisms underlying MSC and leukocyte migration are similar in terms of their migratory dynamics.55 P-selectin glycoprotein ligand-1 (PSGL-1) and E-selectin ligand-1 (ESL-1) are major proteins involved in leukocyte migration that interact with P-selectin and E-selectin present in vascular endothelial cells. However, these promoters are not present in MSCs (Figure 2).53,67

Figure 2 Differences in adhesion protein molecules between leukocytes and mesenchymal stem cells during rolling stages and rolling arrest stage of MSC. (A) The rolling stage of leukocytes starts with adhesion to endothelium with ESL-1 and PSGL-1 on leukocytes. (B) The rolling stage of MSC starts with the adhesion to endothelium with Galectin-1 and CD24 on MSC, and the rolling arrest stage was caused by chemokines that were encountered in the rolling stage and VLA-4 with a high affinity for VACM present in endothelial cells.

Abbreviations: ESL-1, E-selectin ligand-1; PSGL-1, P-selectin glycoprotein ligand-1 VLA-4, very late antigen-4; VCAM, vascular cell adhesion molecule-1.

The initial rolling is facilitated by selectins expressed on the surface of endothelial cells. Various glycoproteins on the surface of MSCs can bind to the selectins and continue the rolling process.68 However, the mechanism of binding of the glycoprotein on MSCs to the selectins is still unclear.69,70 P-selectins and E-selectins, major cell-cell adhesion molecules expressed by endothelial cells, adhere to migrated cells adjacent to endothelial cells and can trigger the rolling process.71 For leukocyte migration, P-selectin glycoprotein ligand-1 (PSGL-1) and E-selectin ligand-1 (ESL-1) expressed on the membranes of leukocytes interact with P-selectins and E-selectins on the endothelial cells, initiating the process.72,73 As already mentioned, MSCs express neither PSGL-1 nor ESL-1. Instead, they express galectin-1 and CD24 on their surfaces, and these bind to E-selectin or P-selectin (Figure 2).7476

In the migratory activation step, MSC receptors are activated in response to inflammatory cytokines, including CXCL12, CXCL8, CXCL4, CCL2, and CCL7.77 The corresponding activation of chemokine receptors of MSCs in response to inflammatory cytokines results in an accumulation of MSCs.58,78 For example, inflamed tissues release inflammatory cytokines,79 and specifically, fibroblasts release CXCL12, which further induces the accumulation of MSCs through ligandreceptor interaction after exposure to hypoxia and cytokine-rich environments in the rat model of inflammation.7982 Previous studies have reported that overexpressing CXCR4, which is a receptor to recognize CXCL12, in MSCs improves the homing ability of MSCs toward inflamed sites.83,84 In short, cytokines are significantly involved in the homing mechanism of MSCs.53

The rolling arrest stage is facilitated by integrin 41 (VLA-4) on MSC.85 VLA-4 is expressed by MSCs which are first activated by CXCL-12 and TNF- chemokines, and activated VLA-4 binds to VCAM-1 expressed on endothelial cells to stop the rotational movement (Figure 2).86,87

Karp et al categorized the migration of MSCs as either systemic homing or non-systemic homing. Systemic homing refers to the process of migration through blood vessels and then across the vascular endothelium near the inflamed site.67,88 The process of migration after passing through the vessels or local injection is called non-systemic homing. In non-systemic migration, stem cells migrate through a chemokine concentration gradient (Figure 3).89 MSCs secrete matrix metalloproteinases (MMPs) during migration. The mechanism underlying MSC migration is currently undefined but MSC migration can be advanced by remodeling the matrix through the secretion of various enzymes.9093 The migration of MSCs to the damaged area is induced by chemokines released from the injured site, such as IL-8, TNF-, insulin-like growth factor (IGF-1), and platelet-derived growth factors (PDGF).9496 MSCs migrate toward the damaged area following a chemokine concentration gradient.87

Figure 3 Differences between systemic and non-systemic homing mechanisms. Both systemic and non-systemic homing to the extracellular matrix and stem cells to their destination, MSCs secrete MMPs and remodel the extracellular matrix.

Abbreviation: MMP, matrix metalloproteinase.

RA is a chronic inflammatory autoimmune disease characterized by distinct painful stiff joints and movement disorders.97 RA affects approximately 1% of the worlds population.98 RA is primarily induced by macrophages, which are involved in the innate immune response and are also involved in adaptive immune responses, together with B cells and T cells.99 Inflammatory diseases are caused by high levels of inflammatory cytokines and a hypoxic low-pH environment in the joints.100,101 Fibroblast-like synoviocytes (FLSs) and accumulated macrophages and neutrophils in the synovium of inflamed joints also express various chemokines.102,103 Chemokines from inflammatory reactions can induce migration of white blood cells and stem cells, which are involved in angiogenesis around joints.101,104,105 More than 50 chemokines are present in the rheumatoid synovial membrane (Table 2). Of the chemokines in the synovium, CXCL12, MIP1-a, CXCL8, and PDGF are the main ones that attract MSCs.106 In the RA environment, CXCL12, a ligand for CXCR4 on MSCs, had 10.71 times higher levels of chemokines than in the normal synovial cell environment. MIP-1a, a chemokine that gathers inflammatory cells, is a ligand for CCR1, which is normally expressed on MSC.107,108 CXCL8 is a ligand for CXCR1 and CXCR2 on MSCs and induces the migration of neutrophils and macrophages, leading to ROS in synovial cells.59 PDGF is a regulatory peptide that is upregulated in the synovial tissue of RA patients.109 PDGF induces greater MSC migration than CXCL12.110 Importantly, stem cells not only have the homing ability to inflamed joints but also have potential as cell therapy with the anti-apoptotic, anti-catabolic, and anti-fibrotic effect of MSC.111 In preclinical trials, MSC treatment has been extensively investigated in collagen-induced arthritis (CIA), a common autoimmune animal model used to study RA. In the RA model, MSCs downregulated inflammatory cytokines such as IFN-, TNF-, IL-4, IL-12, and IL1, and antibodies against collagen, while anti-inflammatory cytokines, such as tumor necrosis factor-inducible gene 6 protein (TSG-6), prostaglandin E2 (PGE2), transforming growth factor-beta (TGF-), IL-10, and IL-6, were upregulated.112116

Table 2 Rheumatoid Arthritis (RA) Chemokines Present in the Pathological Environment and Chemokine Receptors Present in Mesenchymal Stem Cells

Genetic engineering can improve the therapeutic potential of MSCs, including long-term survival, angiogenesis, differentiation into specific lineages, anti- and pro-inflammatory activity, and migratory properties (Figure 4).117,118 Although MSCs already have an intrinsic homing ability, the targeting ability of MSCs and their derivatives, such as membrane vesicles, which are utilized to produce MSC mimicking nanoencapsulation, can be enhanced.118 The therapeutic potential of MSCs can be magnified by reprogramming MSCs via upregulation or downregulation of their native genes, resulting in controlled production of the target protein, or by introducing foreign genes that enable MSCs to express native or non-native products, for example, non-native soluble tumor necrosis factor (TNF) receptor 2 can inhibit TNF-alpha signaling in RA therapies.28

Figure 4 Genetic engineering of mesenchymal stem cells to enhance therapeutic efficacy.

Abbreviations: Sfrp2, secreted frizzled-related protein 2; IGF1, insulin-like growth factor 1; IL-2, interleukin-2; IL-12, interleukin-12; IFN-, interferon-beta; CX3CL1, C-X3-C motif chemokine ligand 1; VEGF, vascular endothelial growth factor; HGF, human growth factor; FGF, fibroblast growth factor; IL-10, interleukin-10; IL-4, interleukin-4; IL18BP, interleukin-18-binding protein; IFN-, interferon-alpha; SDF1, stromal cell-derived factor 1; CXCR4, C-X-C motif chemokine receptor 4; CCR1, C-C motif chemokine receptor 1; BMP2, bone morphogenetic protein 2; mHCN2, mouse hyperpolarization-activated cyclic nucleotide-gated.

MSCs can be genetically engineered using different techniques, including by introducing particular genes into the nucleus of MSCs or editing the genome of MSCs (Figure 5).119 Foreign genes can be transferred into MSCs using liposomes (chemical method), electroporation (physical method), or viral delivery (biological method). Cationic liposomes, also known as lipoplexes, can stably compact negatively charged nucleic acids, leading to the formation of nanomeric vesicular structure.120 Cationic liposomes are commonly produced with a combination of a cationic lipid such as DOTAP, DOTMA, DOGS, DOSPA, and neutral lipids, such as DOPE and cholesterol.121 These liposomes are stable enough to protect their bound nucleic acids from degradation and are competent to enter cells via endocytosis.120 Electroporation briefly creates holes in the cell membrane using an electric field of 1020 kV/cm, and the holes are then rapidly closed by the cells membrane repair mechanism.122 Even though the electric shock induces irreversible cell damage and non-specific transport into the cytoplasm leads to cell death, electroporation ensures successful gene delivery regardless of the target cell or organism. Viral vectors, which are derived from adenovirus, adeno-associated virus (AAV), or lentivirus (LV), have been used to introduce specific genes into MSCs. Recombinant lentiviral vectors are the most widely used systems due to their high tropism to dividing and non-dividing cells, transduction efficiency, and stable expression of transgenes in MSCs, but the random genome integration of transgenes can be an obstacle in clinical applications.123 Adenovirus and AAV systems are appropriate alternative strategies because currently available strains do not have broad genome integration and a strong immune response, unlike LV, thus increasing success and safety in clinical trials.124 As a representative, the Oxford-AstraZeneca COVID-19 vaccine, which has been authorized in 71 countries as a vaccine for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which spread globally and led to the current pandemic, transfers the spike protein gene using an adenovirus-based viral vector.125 Furthermore, there are two AAV-based gene therapies: Luxturna for rare inherited retinal dystrophy and Zolgensma for spinal muscular atrophy.126

Figure 5 Genetic engineering techniques used in the production of bioengineered mesenchymal stem cells.

Clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 were recently used for genome editing and modification because of their simpler design and higher efficiency for genome editing, however, there are safety issues such as off-target effects that induce mutations at sites other than the intended target site.127 The foreign gene is then commonly transferred into non-integrating forms such as plasmid DNA and messenger RNA (mRNA).128

The gene expression machinery can also be manipulated at the cytoplasmic level through RNA interference (RNAi) technology, inhibition of gene expression, or translation using neutralizing targeted mRNA molecules with sequence-specific small RNA molecules such as small interfering RNA (siRNA) or microRNA (miRNA).129 These small RNAs can form enzyme complexes that degrade mRNA molecules and thus decrease their activity by inhibiting translation. Moreover, the pre-transcriptional silencing mechanism of RNAi can induce DNA methylation at genomic positions complementary to siRNA or miRNA with enzyme complexes.

CXC chemokine receptor 4 (CXCR4) is one of the most potent chemokine receptors that is genetically engineered to enhance the migratory properties of MSCs.130 CXCR4 is a chemokine receptor specific for stromal-derived factor-1 (SDF-1), also known as CXC motif chemokine 12 (CXCL12), which is produced by damaged tissues, such as the area of inflammatory bone destruction.131 Several studies on engineering MSCs to increase the expression of the CXCR4 gene have reported a higher density of the CXCR4 receptor on their outer cell membrane and effectively increased the migration of MSCs toward SDF-1.83,132,133 CXC chemokine receptor 7 (CXCR7) also had a high affinity for SDF-1, thus the SDF-1/CXCR7 signaling axis was used to engineer the MSCs.134 CXCR7-overexpressing MSCs in a cerebral ischemia-reperfusion rat hippocampus model promoted migration based on an SDF-1 gradient, cooperating with the SDF-1/CXCR4 signaling axis (Figure 6).37

Figure 6 Engineered mesenchymal stem cells with enhanced migratory abilities.

Abbreviations: CXCR4, C-X-C motif chemokine receptor 4; CXCR7, C-X-C motif chemokine receptor 7; SDF1, stromal cell-derived factor 1; CXCR1, C-X-C motif chemokine receptor 1; IL-8, interleukin-8; Aqp1, aquaporin 1; FAK, focal adhesion kinase.

CXC chemokine receptor 1 (CXCR1) enhances MSC migratory properties.59 CXCR1 is a receptor for IL-8, which is the primary cytokine involved in the recruitment of neutrophils to the site of damage or infection.135 In particular, the IL-8/CXCR1 axis is a key factor for the migration of MSCs toward human glioma cell lines, such as U-87 MG, LN18, U138, and U251, and CXCR1-overexpressing MSCs showed a superior capacity to migrate toward glioma cells and tumors in mice bearing intracranial human gliomas.136

The migratory properties of MSCs were also controlled via aquaporin-1 (Aqp1), which is a water channel molecule that transports water across the cell membrane and regulates endothelial cell migration.137 Aqp1-overexpressing MSCs showed enhanced migration to fracture gap of a rat fracture model with upregulated focal adhesion kinase (FAK) and -catenin, which are important regulators of cell migration.138

Nur77, also known as nerve growth factor IB or NR4A1, and nuclear receptor-related 1 (Nurr1), can play a role in improving the migratory capabilities of MSCs.139,140 The migrating MSCs expressed higher levels of Nur77 and Nurr1 than the non-migrating MSCs, and overexpression of these two nuclear receptors functioning as transcription factors enhanced the migration of MSCs toward SDF-1. The migration of cells is closely related to the cell cycle, and normally, cells in the late S or G2/M phase do not migrate.141 The overexpression of Nur77 and Nurr1 increased the proportion of MSCs in the G0/G1-phase similar to the results of migrating MSCs had more cells in the G1-phase.

MSC mimicking nanoencapsulations are nanoparticles combined with MSC membrane vesicles and these NPs have the greatest advantages as drug delivery systems due to the sustained homing ability of MSCs as well as the advantages of NPs. Particles sized 10150 nm have great advantages in drug delivery systems because they can pass more freely through the cell membrane by the interaction with biomolecules, such as clathrin and caveolin, to facilitate uptake across the cell membrane compared with micron-sized materials.142,143 Various materials have been used to formulate NPs, including silica, polymers, metals, and lipids.144,145 NPs have an inherent ability, called passive targeting, to accumulate at specific sites based on their physicochemical properties such as size, surface charge, surface hydrophilicity, and geometry.146148 However, physicochemical properties are not enough to target specific tissues or damaged tissues, and thus active targeting is a clinically approved strategy involving the addition of ligands that can bind to surface receptors on target cells or tissues.149,150 MSC mimicking nanoencapsulation uses natural or genetically engineered MSC membranes to coat synthetic NPs, producing artificial ectosomes and fusing them with liposomes to increase their targeting ability (Figure 7).151 Especially, MSCs have been studied for targeting inflammation and regenerative drugs, and the mechanism and efficacy of migration toward inflamed tissues have been actively investigated.152 MSC mimicking nanoencapsulation can mimic the well-known migration ability of MSCs and can be equally utilized without safety issues from the direct application of using MSCs. Furthermore, cell membrane encapsulations have a wide range of functions, including prolonged blood circulation time and increased active targeting efficacy from the source cells.153,154 MSC mimicking encapsulations enter recipient cells using multiple pathways.155 MSC mimicking encapsulations can fuse directly with the plasma membrane and can also be taken up through phagocytosis, micropinocytosis, and endocytosis mediated by caveolin or clathrin.156 MSC mimicking encapsulations can be internalized in a highly cell type-specific manner that depends on the recognition of membrane surface molecules by the cell or tissue.157 For example, endothelial colony-forming cell (ECFC)-derived exosomes were shown CXCR4/SDF-1 interaction and enhanced delivery toward the ischemic kidney, and Tspan8-alpha4 complex on lymph node stroma derived extracellular vesicles induced selective uptake by endothelial cells or pancreatic cells with CD54, serving as a major ligand.158,159 Therefore, different source cells may contain protein signals that serve as ligands for other cells, and these receptorligand interactions maximized targeted delivery of NPs.160 This natural mechanism inspired the application of MSC membranes to confer active targeting to NPs.

Figure 7 Mesenchymal stem cell mimicking nanoencapsulation.

Cell membrane-coated NPs (CMCNPs) are biomimetic strategies developed to mimic the properties of cell membranes derived from natural cells such as erythrocytes, white blood cells, cancer cells, stem cells, platelets, or bacterial cells with an NP core.161 Core NPs made of polymer, silica, and metal have been evaluated in attempts to overcome the limitations of conventional drug delivery systems but there are also issues of toxicity and reduced biocompatibility associated with the surface properties of NPs.162,163 Therefore, only a small number of NPs have been approved for medical application by the FDA.164 Coating with cell membrane can enhance the biocompatibility of NPs by improving immune evasion, enhancing circulation time, reducing RES clearance, preventing serum protein adsorption by mimicking cell glycocalyx, which are chemical determinants of self at the surfaces of cells.151,165 Furthermore, the migratory properties of MSCs can also be transferred to NPs by coating them with the cell membrane.45 Coating NPs with MSC membranes not only enhances biocompatibility but also maximizes the therapeutic effect of NPs by mimicking the targeting ability of MSCs.166 Cell membrane-coated NPs are prepared in three steps: extraction of cell membrane vesicles from the source cells, synthesis of the core NPs, and fusion of the membrane vesicles and core NPs to produce cell membrane-coated NPs (Figure 8).167 Cell membrane vesicles, including extracellular vesicles (EVs), can be harvested through cell lysis, mechanical disruption, and centrifugation to isolate, purify the cell membrane vesicles, and remove intracellular components.168 All the processes must be conducted under cold conditions, with protease inhibitors to minimize the denaturation of integral membrane proteins. Cell lysis, which is classically performed using mechanical lysis, including homogenization, sonication, or extrusion followed by differential velocity centrifugation, is necessary to remove intracellular components. Cytochalasin B (CB), a drug that affects cytoskeletonmembrane interactions, induces secretion of membrane vesicles from source cells and has been used to extract the cell membrane.169 The membrane functions of the source cells are preserved in CB-induced vesicles, forming biologically active surface receptors and ion pumps.170 Furthermore, CB-induced vesicles can encapsulate drugs and NPs successfully, and the vesicles can be harvested by centrifugation without a purification step to remove nuclei and cytoplasm.171 Clinically translatable membrane vesicles require scalable production of high volumes of homogeneous vesicles within a short period. Although mechanical methods (eg, shear stress, ultrasonication, or extrusion) are utilized, CB-induced vesicles have shown potential for generating membrane encapsulation for nano-vectors.168 The advantages of CB-induced vesicles versus other methods are compared in Table 3.

Table 3 Comparison of Membrane Vesicle Production Methods

Figure 8 MSC membrane-coated nanoparticles.

Abbreviations: EVs, extracellular vesicles; NPs, nanoparticles.

After extracting cell membrane vesicles, synthesized core NPs are coated with cell membranes, including surface proteins.172 Polymer NPs and inorganic NPs are adopted as materials for the core NPs of CMCNPs, and generally, polylactic-co-glycolic acid (PLGA), polylactic acid (PLA), chitosan, and gelatin are used. PLGA has been approved by FDA is the most common polymer of NPs.173 Biodegradable polymer NPs have gained considerable attention in nanomedicine due to their biocompatibility, nontoxic properties, and the ability to modify their surface as a drug carrier.174 Inorganic NPs are composed of gold, iron, copper, and silicon, which have hydrophilic, biocompatible, and highly stable properties compared with organic materials.175 Furthermore, some photosensitive inorganic NPs have the potential for use in photothermal therapy (PTT) and photodynamic therapy (PDT).176 The fusion of cell membrane vesicles and core NPs is primarily achieved via extrusion or sonication.165 Cell membrane coating of NPs using mechanical extrusion is based on a different-sized porous membrane where core NPs and vesicles are forced to generate vesicle-particle fusion.177 Ultrasonic waves are applied to induce the fusion of vesicles and NPs. However, ultrasonic frequencies need to be optimized to improve fusion efficiency and minimize drug loss and protein degradation.178

CMCNPs have extensively employed to target and treat cancer using the membranes obtained from red blood cell (RBC), platelet and cancer cell.165 In addition, membrane from MSC also utilized to target tumor and ischemia with various types of core NPs, such as MSC membrane coated PLGA NPs targeting liver tumors, MSC membrane coated gelatin nanogels targeting HeLa cell, MSC membrane coated silica NPs targeting HeLa cell, MSC membrane coated PLGA NPs targeting hindlimb ischemia, and MSC membrane coated iron oxide NPs for targeting the ischemic brain.179183 However, there are few studies on CMCNPs using stem cells for the treatment of arthritis. Increased targeting ability to arthritis was introduced using MSC-derived EVs and NPs.184,185 MSC membrane-coated NPs are proming strategy for clearing raised concerns from direct use of MSC (with or without NPs) in terms of toxicity, reduced biocompatibility, and poor targeting ability of NPs for the treatment of arthritis.

Exosomes are natural NPs that range in size from 40 nm to 120 nm and are derived from the multivesicular body (MVB), which is an endosome defined by intraluminal vesicles (ILVs) that bud inward into the endosomal lumen, fuse with the cell surface, and are then released as exosomes.186 Because of their ability to express receptors on their surfaces, MSC-derived exosomes are also considered potential candidates for targeting.187 Exosomes are commonly referred to as intracellular communication molecules that transfer various compounds through physiological mechanisms such as immune response, neural communication, and antigen presentation in diseases such as cancer, cardiovascular disease, diabetes, and inflammation.188

However, there are several limitations to the application of exosomes as targeted therapeutic carriers. First, the limited reproducibility of exosomes is a major challenge. In this field, the standardized techniques for isolation and purification of exosomes are lacking, and conventional methods containing multi-step ultracentrifugation often lead to contamination of other types of EVs. Furthermore, exosomes extracted from cell cultures can vary and display inconsistent properties even when the same type of donor cells were used.189 Second, precise characterization studies of exosomes are needed. Unknown properties of exosomes can hinder therapeutic efficiencies, for example, when using exosomes as cancer therapeutics, the use of cancer cell-derived exosomes should be avoided because cancer cell-derived exosomes may contain oncogenic factors that may contribute to cancer progression.190 Finally, cost-effective methods for the large-scale production of exosomes are needed for clinical application. The yield of exosomes is much lower than EVs. Depending on the exosome secretion capacity of donor cells, the yield of exosomes is restricted, and large-scale cell culture technology for the production of exosomes is high difficulty and costly and isolation of exosomes is the time-consuming and low-efficient method.156

Ectosome is an EV generated by outward budding from the plasma membrane followed by pinching off and release to the extracellular parts. Recently, artificially produced ectosome utilized as an alternative to exosomes in targeted therapeutics due to stable productivity regardless of cell type compared with conventional exosome. Artificial ectosomes, containing modified cargo and targeting molecules have recently been introduced for specific purposes (Figure 9).191,192 Artificial ectosomes are typically prepared by breaking bigger cells or cell membrane fractions into smaller ectosomes, similar size to natural exosomes, containing modified cargo such as RNA molecules, which control specific genes, and chemical drugs such as anticancer drugs.193 Naturally secreted exosomes in conditioned media from modified source cells can be harvested by differential ultracentrifugation, density gradients, precipitation, filtration, and size exclusion chromatography for exosome separation.194 Even though there are several commercial kits for isolating exosomes simply and easily, challenges in compliant scalable production on a large scale, including purity, homogeneity, and reproducibility, have made it difficult to use naturally secreted exosomes in clinical settings.195 Therefore, artificially produced ectosomes are appropriate for use in clinical applications, with novel production methods that can meet clinical production criteria. Production of artificially produced ectosomes begins by breaking the cell membrane fraction of cultured cells and then using them to produce cell membrane vesicles to form ectosomes. As mentioned above, cell membrane vesicles are extracted from source cells in several ways, and cell membrane vesicles are extracted through polycarbonate membrane filters to reduce the mean size to a size similar to that of natural exosomes.196 Furthermore, specific microfluidic devices mounted on microblades (fabricated in silicon nitride) enable direct slicing of living cells as they flow through the hydrophilic microchannels of the device.197 The sliced cell fraction reassembles and forms ectosomes. There are several strategies for loading exogenous therapeutic cargos such as drugs, DNA, RNA, lipids, metabolites, and proteins, into exosomes or artificial ectosomes in vitro: electroporation, incubation for passive loading of cargo or active loading with membrane permeabilizer, freeze and thaw cycles, sonication, and extrusion.198 In addition, protein or RNA molecules can be loaded by co-expressing them in source cells via bio-engineering, and proteins designed to interact with the protein inside the cell membrane can be loaded actively into exosomes or artificial ectosomes.157 Targeting molecules at the surface of exosomes or artificial ectosomes can also be engineered in a manner similar to the genetic engineering of MSCs.

Figure 9 Mesenchymal stem cell-derived exosomes and artificial ectosomes. (A) Wound healing effect of MSC-derived exosomes and artificial ectosomes,231 (B) treatment of organ injuries by MSC-derived exosomes and artificial ectosomes,42,232234 (C) anti-cancer activity of MSC-derived exosomes and artificial ectosomes.200,202,235

Most of the exosomes derived from MSCs for drug delivery have employed miRNAs or siRNAs, inhibiting translation of specific mRNA, with anticancer activity, for example, miR-146b, miR-122, and miR-379, which are used for cancer targeting by membrane surface molecules on MSC-derived exosomes.199201 Drugs such as doxorubicin, paclitaxel, and curcumin were also loaded into MSC-derived exosomes to target cancer.202204 However, artificial ectosomes derived from MSCs as arthritis therapeutics remains largely unexplored area, while EVs, mixtures of natural ectosomes and exosomes, derived from MSCs have studied in the treatment of arthritis.184 Artificial ectosomes with intrinsic tropism from MSCs plus additional targeting ability with engineering increase the chances of ectosomes reaching target tissues with ligandreceptor interactions before being taken up by macrophages.205 Eventually, this will decrease off-target binding and side effects, leading to lower therapeutic dosages while maintaining therapeutic efficacy.206,207

Liposomes are spherical vesicles that are artificially synthesized through the hydration of dry phospholipids.208 The clinically available liposome is a lipid bilayer surrounding a hollow core with a diameter of 50150 nm. Therapeutic molecules, such as anticancer drugs (doxorubicin and daunorubicin citrate) or nucleic acids, can be loaded into this hollow core for delivery.209 Due to their amphipathic nature, liposomes can load both hydrophilic (polar) molecules in an aqueous interior and hydrophobic (nonpolar) molecules in the lipid membrane. They are well-established biomedical applications and are the most common nanostructures used in advanced drug delivery.210 Furthermore, liposomes have several advantages, including versatile structure, biocompatibility, low toxicity, non-immunogenicity, biodegradability, and synergy with drugs: targeted drug delivery, reduction of the toxic effect of drugs, protection against drug degradation, and enhanced circulation half-life.211 Moreover, surfaces can be modified by either coating them with a functionalized polymer or PEG chains to improve targeted delivery and increase their circulation time in biological systems.212 Liposomes have been investigated for use in a wide variety of therapeutic applications, including cancer diagnostics and therapy, vaccines, brain-targeted drug delivery, and anti-microbial therapy. A new approach was recently proposed for providing targeting features to liposomes by fusing them with cell membrane vesicles, generating molecules called membrane-fused liposomes (Figure 10).213 Cell membrane vesicles retain the surface membrane molecules from source cells, which are responsible for efficient tissue targeting and cellular uptake by target cells.214 However, the immunogenicity of cell membrane vesicles leads to their rapid clearance by macrophages in the body and their low drug loading efficiencies present challenges for their use as drug delivery systems.156 However, membrane-fused liposomes have advantages of stability, long half-life in circulation, and low immunogenicity due to the liposome, and the targeting feature of cell membrane vesicles is completely transferred to the liposome.215 Furthermore, the encapsulation efficiencies of doxorubicin were similar when liposomes and membrane-fused liposomes were used, indicating that the relatively high drug encapsulation capacity of liposomes was maintained during the fusion process.216 Combining membrane-fused liposomes with macrophage-derived membrane vesicles showed differential targeting and cytotoxicity against normal and cancerous cells.217 Although only a few studies have been conducted, these results corroborate that membrane-fused liposomes are a potentially promising future drug delivery system with increased targeting ability. MSCs show intrinsic tropism toward arthritis, and further engineering and modification to enhance their targeting ability make them attractive candidates for the development of drug delivery systems. Fusing MSC exosomes with liposomes, taking advantage of both membrane vesicles and liposomes, is a promising technique for future drug delivery systems.

Figure 10 Mesenchymal stem cell membrane-fused liposomes.

MSCs have great potential as targeted therapies due to their greater ability to home to targeted pathophysiological sites. The intrinsic ability to home to wounds or to the tumor microenvironment secreting inflammatory mediators make MSCs and their derivatives targeting strategies for cancer and inflammatory disease.218,219 Contrary to the well-known homing mechanisms of various blood cells, it is still not clear how homing occurs in MSCs. So far, the mechanism of MSC tethering, which connects long, thin cell membrane cylinders called tethers to the adherent area for migration, has not been clarified. Recent studies have shown that galectin-1, VCAM-1, and ICAM are associated with MSC tethering,53,220 but more research is needed to accurately elucidate the tethering mechanism of MSCs. MSC chemotaxis is well defined and there is strong evidence relating it to the homing ability of MSCs.53 Chemotaxis involves recognizing chemokines through chemokine receptors on MSCs and migrating to chemokines in a gradient-dependent manner.221 RA, a representative inflammatory disease, is associated with well-profiled chemokines such as CXCR1, CXCR4, and CXCR7, which are recognized by chemokine receptors on MSCs. In addition, damaged joints in RA continuously secrete cytokines until they are treated, giving MSCs an advantage as future therapeutic agents for RA.222 However, there are several obstacles to utilizing MSCs as RA therapeutics. In clinical settings, the functional capability of MSCs is significantly affected by the health status of the donor patient.223 MSC yield is significantly reduced in patients undergoing steroid-based treatment and the quality of MSCs is dependent on the donors age and environment.35 In addition, when MSCs are used clinically, cryopreservation and defrosting are necessary, but these procedures shorten the life span of MSCs.224 Therefore, NPs mimicking MSCs are an alternative strategy for overcoming the limitations of MSCs. Additionally, further engineering and modification of MSCs can enhance the therapeutic effect by changing the targeting molecules and loaded drugs. In particular, upregulation of receptors associated with chemotaxis through genetic engineering can confer the additional ability of MSCs to home to specific sites, while the increase in engraftment maximizes the therapeutic effect of MSCs.36,225

Furthermore, there are several methods that can be used to exploit the targeting ability of MSCs as drug delivery systems. MSCs mimicking nanoencapsulation, which consists of MSC membrane-coated NPs, MSC-derived artificial ectosomes, and MSC membrane-fused liposomes, can mimic the targeting ability of MSCs while retaining the advantages of NPs. MSC-membrane-coated NPs are synthesized using inorganic or polymer NPs and membranes from MSCs to coat inner nanosized structures. Because they mimic the biological characteristics of MSC membranes, MSC-membrane-coated NPs can not only escape from immune surveillance but also effectively improve targeting ability, with combined functions of the unique properties of core NPs and MSC membranes.226 Exosomes are also an appropriate candidate for use in MSC membranes, utilizing these targeting abilities. However, natural exosomes lack reproducibility and stable productivity, thus artificial ectosomes with targeting ability produced via synthetic routes can increase the local concentration of ectosomes at the targeted site, thereby reducing toxicity and side effects and maximizing therapeutic efficacy.156 MSC membrane-fused liposomes, a novel system, can also transfer the targeting molecules on the surface of MSCs to liposomes; thus, the advantages of liposomes are retained, but with targeting ability. With advancements in nanotechnology of drug delivery systems, the research in cell-mimicking nanoencapsulation will be very useful. Efficient drug delivery systems fundamentally improve the quality of life of patients with a low dose of medication, low side effects, and subsequent treatment of diseases.227 However, research on cell-mimicking nanoencapsulation is at an early stage, and several problems need to be addressed. To predict the nanotoxicity of artificially synthesized MSC mimicking nanoencapsulations, interactions between lipids and drugs, drug release mechanisms near the targeted site, in vivo compatibility, and immunological physiological studies must be conducted before clinical application.

This work was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF-2019M3A9H1103690), by the Gachon University Gil Medical Center (FRD2021-03), and by the Gachon University research fund of 2020 (GGU-202008430004).

The authors report no conflicts of interest in this work.

1. Chapel A, Bertho JM, Bensidhoum M, et al. Mesenchymal stem cells home to injured tissues when co-infused with hematopoietic cells to treat a radiation-induced multi-organ failure syndrome. J Gene Med. 2003;5(12):10281038. doi:10.1002/jgm.452

2. Park JS, Suryaprakash S, Lao YH, Leong KW. Engineering mesenchymal stem cells for regenerative medicine and drug delivery. Methods. 2015;84:316. doi:10.1016/j.ymeth.2015.03.002

3. Ringe J, Burmester GR, Sittinger M. Regenerative medicine in rheumatic disease-progress in tissue engineering. Nat Rev Rheumatol. 2012;8(8):493498. doi:10.1038/nrrheum.2012.98

4. Friedenstein AJ, Petrakova KV, Kurolesova AI, Frolova GP. Heterotopic of bone marrow. Analysis of precursor cells for osteogenic and hematopoietic tissues. Transplantation. 1968;6(2):230247. doi:10.1097/00007890-196803000-00009

5. Zuk PA, Zhu M, Ashjian P, et al. Human adipose tissue is a source of multipotent stem cells. Mol Biol Cell. 2002;13(12):42794295. doi:10.1091/mbc.e02-02-0105

6. Crisan M, Yap S, Casteilla L, et al. A perivascular origin for mesenchymal stem cells in multiple human organs. Cell Stem Cell. 2008;3(3):301313. doi:10.1016/j.stem.2008.07.003

7. Gronthos S, Mankani M, Brahim J, Robey PG, Shi S. Postnatal human dental pulp stem cells (DPSCs) in vitro and in vivo. Proc Natl Acad Sci U S A. 2000;97(25):1362513630. doi:10.1073/pnas.240309797

8. Young HE, Steele TA, Bray RA, et al. Human reserve pluripotent mesenchymal stem cells are present in the connective tissues of skeletal muscle and dermis derived from fetal, adult, and geriatric donors. Anat Rec. 2001;264(1):5162. doi:10.1002/ar.1128

9. Campagnoli C, Roberts IA, Kumar S, Bennett PR, Bellantuono I, Fisk NM. Identification of mesenchymal stem/progenitor cells in human first-trimester fetal blood, liver, and bone marrow. Blood. 2001;98(8):23962402. doi:10.1182/blood.V98.8.2396

10. Wang HS, Hung SC, Peng ST, et al. Mesenchymal stem cells in the Whartons jelly of the human umbilical cord. Stem Cells. 2004;22(7):13301337. doi:10.1634/stemcells.2004-0013

11. Heo JS, Choi Y, Kim HS, Kim HO. Comparison of molecular profiles of human mesenchymal stem cells derived from bone marrow, umbilical cord blood, placenta and adipose tissue. Int J Mol Med. 2016;37(1):115125. doi:10.3892/ijmm.2015.2413

12. Drela K, Stanaszek L, Snioch K, et al. Bone marrow-derived from the human femoral shaft as a new source of mesenchymal stem/stromal cells: an alternative cell material for banking and clinical transplantation. Stem Cell Res Ther. 2020;11(1):262. doi:10.1186/s13287-020-01697-5

13. Li J, Wong WH, Chan S, et al. Factors affecting mesenchymal stromal cells yield from bone marrow aspiration. Chin J Cancer Res. 2011;23(1):4348. doi:10.1007/s11670-011-0043-1

14. Melief SM, Zwaginga JJ, Fibbe WE, Roelofs H. Adipose tissue-derived multipotent stromal cells have a higher immunomodulatory capacity than their bone marrow-derived counterparts. Stem Cells Transl Med. 2013;2(6):455463. doi:10.5966/sctm.2012-0184

15. Trivanovic D, Jaukovic A, Popovic B, et al. Mesenchymal stem cells of different origin: comparative evaluation of proliferative capacity, telomere length and pluripotency marker expression. Life Sci. 2015;141:6173. doi:10.1016/j.lfs.2015.09.019

16. Lefevre S, Knedla A, Tennie C, et al. Synovial fibroblasts spread rheumatoid arthritis to unaffected joints. Nat Med. 2009;15(12):14141420. doi:10.1038/nm.2050

17. Cyranoski D. Japans approval of stem-cell treatment for spinal-cord injury concerns scientists. Nature. 2019;565(7741):544545. doi:10.1038/d41586-019-00178-x

18. Cofano F, Boido M, Monticelli M, et al. Mesenchymal stem cells for spinal cord injury: current options, limitations, and future of cell therapy. Int J Mol Sci. 2019;20(11):2698. doi:10.3390/ijms20112698

19. Liau LL, Looi QH, Chia WC, Subramaniam T, Ng MH, Law JX. Treatment of spinal cord injury with mesenchymal stem cells. Cell Biosci. 2020;10:112. doi:10.1186/s13578-020-00475-3

20. Williams AR, Hare JM, Dimmeler S, Losordo D. Mesenchymal stem cells: biology, pathophysiology, translational findings, and therapeutic implications for cardiac disease. Circ Res. 2011;109(8):923940. doi:10.1161/CIRCRESAHA.111.243147

21. Karantalis V, Hare JM. Use of mesenchymal stem cells for therapy of cardiac disease. Circ Res. 2015;116(8):14131430. doi:10.1161/CIRCRESAHA.116.303614

22. Bernstein HS, Srivastava D. Stem cell therapy for cardiac disease. Pediatr Res. 2012;71(4 Pt 2):491499. doi:10.1038/pr.2011.61

23. Guo Y, Yu Y, Hu S, Chen Y, Shen Z. The therapeutic potential of mesenchymal stem cells for cardiovascular diseases. Cell Death Dis. 2020;11(5):349. doi:10.1038/s41419-020-2542-9

24. Spaeth E, Klopp A, Dembinski J, Andreeff M, Marini F. Inflammation and tumor microenvironments: defining the migratory itinerary of mesenchymal stem cells. Gene Ther. 2008;15(10):730738. doi:10.1038/gt.2008.39

25. Vos T, Allen C, Arora M, et al. Global, regional, and national incidence, prevalence, and years lived with disability for 310 diseases and injuries, 19902015: a systematic analysis for the Global Burden of Disease Study 2015. Lancet. 2016;388(10053):15451602.

26. Singh JA, Wells GA, Christensen R, et al. Adverse effects of biologics: a network meta-analysis and Cochrane overview. Cochrane Database Syst Rev. 2011;(2):CD008794. doi:10.1002/14651858.CD008794.pub2

27. Majithia V, Geraci SA. Rheumatoid arthritis: diagnosis and management. Am J Med. 2007;120(11):936939. doi:10.1016/j.amjmed.2007.04.005

28. Park N, Rim YA, Jung H, et al. Etanercept-synthesising mesenchymal stem cells efficiently ameliorate collagen-induced arthritis. Sci Rep. 2017;7:39593. doi:10.1038/srep39593

29. Herberts CA, Kwa MS, Hermsen HP. Risk factors in the development of stem cell therapy. J Transl Med. 2011;9:29. doi:10.1186/1479-5876-9-29

30. Rodriguez-Fuentes DE, Fernandez-Garza LE, Samia-Meza JA, Barrera-Barrera SA, Caplan AI, Barrera-Saldana HA. Mesenchymal stem cells current clinical applications: a systematic review. Arch Med Res. 2021;52(1):93101. doi:10.1016/j.arcmed.2020.08.006

31. Kabat M, Bobkov I, Kumar S, Grumet M. Trends in mesenchymal stem cell clinical trials 20042018: is efficacy optimal in a narrow dose range? Stem Cells Transl Med. 2020;9(1):1727. doi:10.1002/sctm.19-0202

32. Leibacher J, Henschler R. Biodistribution, migration and homing of systemically applied mesenchymal stem/stromal cells. Stem Cell Res Ther. 2016;7:7. doi:10.1186/s13287-015-0271-2

33. Zheng B, von See MP, Yu E, et al. Quantitative magnetic particle imaging monitors the transplantation, biodistribution, and clearance of stem cells in vivo. Theranostics. 2016;6(3):291301. doi:10.7150/thno.13728

34. Gholamrezanezhad A, Mirpour S, Bagheri M, et al. In vivo tracking of 111In-oxine labeled mesenchymal stem cells following infusion in patients with advanced cirrhosis. Nucl Med Biol. 2011;38(7):961967. doi:10.1016/j.nucmedbio.2011.03.008

35. Pittenger MF, Discher DE, Peault BM, Phinney DG, Hare JM, Caplan AI. Mesenchymal stem cell perspective: cell biology to clinical progress. NPJ Regen Med. 2019;4:22. doi:10.1038/s41536-019-0083-6

36. Marquez-Curtis LA, Janowska-Wieczorek A. Enhancing the migration ability of mesenchymal stromal cells by targeting the SDF-1/CXCR4 axis. Biomed Res Int. 2013;2013:561098. doi:10.1155/2013/561098

37. Liu L, Chen JX, Zhang XW, et al. Chemokine receptor 7 overexpression promotes mesenchymal stem cell migration and proliferation via secreting Chemokine ligand 12. Sci Rep. 2018;8(1):204. doi:10.1038/s41598-017-18509-1

38. Rittiner JE, Moncalvo M, Chiba-Falek O, Kantor B. Gene-editing technologies paired with viral vectors for translational research into neurodegenerative diseases. Front Mol Neurosci. 2020;13:148. doi:10.3389/fnmol.2020.00148

39. Srifa W, Kosaric N, Amorin A, et al. Cas9-AAV6-engineered human mesenchymal stromal cells improved cutaneous wound healing in diabetic mice. Nat Commun. 2020;11(1):2470. doi:10.1038/s41467-020-16065-3

40. van Haasteren J, Li J, Scheideler OJ, Murthy N, Schaffer DV. The delivery challenge: fulfilling the promise of therapeutic genome editing. Nat Biotechnol. 2020;38(7):845855. doi:10.1038/s41587-020-0565-5

41. Gowen A, Shahjin F, Chand S, Odegaard KE, Yelamanchili SV. Mesenchymal stem cell-derived extracellular vesicles: challenges in clinical applications. Front Cell Dev Biol. 2020;8:149. doi:10.3389/fcell.2020.00149

42. Lou G, Chen Z, Zheng M, Liu Y. Mesenchymal stem cell-derived exosomes as a new therapeutic strategy for liver diseases. Exp Mol Med. 2017;49(6):e346. doi:10.1038/emm.2017.63

43. Phinney DG, Di Giuseppe M, Njah J, et al. Mesenchymal stem cells use extracellular vesicles to outsource mitophagy and shuttle microRNAs. Nat Commun. 2015;6:8472. doi:10.1038/ncomms9472

44. Villemin E, Ong YC, Thomas CM, Gasser G. Polymer encapsulation of ruthenium complexes for biological and medicinal applications. Nat Rev Chem. 2019;3(4):261282. doi:10.1038/s41570-019-0088-0

45. Su YQ, Zhang TY, Huang T, Gao JQ. Current advances and challenges of mesenchymal stem cells-based drug delivery system and their improvements. Int J Pharma. 2021;600:120477.

46. Kwon S, Kim SH, Khang D, Lee JY. Potential therapeutic usage of nanomedicine for glaucoma treatment. Int J Nanomed. 2020;15:57455765. doi:10.2147/IJN.S254792

47. Sanna V, Sechi M. Therapeutic potential of targeted nanoparticles and perspective on nanotherapies. ACS Med Chem Lett. 2020;11(6):10691073. doi:10.1021/acsmedchemlett.0c00075

Go here to see the original:
Stem Cell Mimicking Nanoencapsulation for Targeting Arthrit | IJN - Dove Medical Press