The Gairdner Foundation announced today that Howard Hughes Medical Institute (HHMI) researchers Thomas M. Jessell and Michael Rosbash are recipients of the prestigious 2012 Canada Gairdner International Awards in recognition of their contributions to medical science.

The awards, which are presented annually, recognize scientists responsible for some of the worlds most significant medical discoveries. Jessell, who became an HHMI investigator at Columbia University in 1985, was honored for discovering basic principles of communication within the nervous system. The Foundation states that Jessells work has been instrumental in revealing important steps in the process that guides the early development of neurons, as they establish the precise connections between the spinal cord and muscles.

Rosbash, who became an HHMI investigator at Brandeis University in 1989, was highlighted for discoveries that have revealed the genetic underpinnings of the circadian clock. Circadian clocks are active throughout the bodys cells, where they use a common genetic mechanism to control the rhythmic activities of various tissues. Rosbash, Jeffrey C. Hall, emeritus professor of biology at Brandeis University, and Michael W. Young of the Laboratory of Genetics at The Rockefeller University, were honored by the Gairdner Foundation for pioneering discoveries concerning the biological clock responsible for circadian rhythms.

The Canada Gairdner Awards will be presented at a dinner in Toronto in October as part of the Gairdner National Program, a month-long lecture series given by Canada Gairdner Award winners at 21 universities from St Johns to Vancouver.

Thomas M. Jessell, Ph.D.

For the past two decades, Thomas Jessell has worked to understand how nerve cells in the developing spinal cord assemble into functional circuits that control sensory perception and motor actions. Ultimately, his research may provide a more thorough understanding of how the central nervous system is constructed and suggest new ways to repair diseased or damaged neurons in the human brain and spinal cord.

There is increasingly persuasive evidence to suggest that many neurodevelopmental and psychiatric disordersfrom motor neuron diseases to autism and schizophreniaresult from defects in the initial assembly of connections in the developing brain, says Jessell. By understanding the cellular and molecular processes that control the normal wiring pattern of these connections, we may eventually be able to design more rational and effective strategies for repairing the defects that underlie brain disorders.

Jessell's work has revealed the details of a molecular pathway that converts nave progenitor cells in the early neural tube into the many different classes of motor neurons and interneurons that assemble together to form functional locomotor circuits. This molecular pathway involves critical environmental signaling molecules such as Sonic hedgehog, and a delicate interplay of nuclear transcription factors that interpret Sonic hedgehog signals to generate diverse neuronal classes.

The principles that have emerged from Jessell's studies in the spinal cord have been found to apply to many other regions of the central nervous system, thus establishing a basic ground plan for brain development. His work has also defined many of the key steps that permit newly generated neurons to form selective connections with their target cells.

One potential strategy for brain repair involves the use of stem cells, and Jessell and his colleagues have demonstrated that mouse embryonic stem cells can be converted into functional motor neurons in a simple procedure that recapitulates the normal molecular program of motor neuron differentiation. Remarkably, these stem cell-derived motor neurons can integrate into the spinal cord in vivo and contribute to functional motor circuits. This work may uncover additional aspects of the basic program of motor neuron development, as well as pointing the way to new cell and drug-based therapies for motor neuron disease and spinal cord injury.

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2012 Gairdner Awards Go to Jessell, Rosbash