The research showed that mice afflicted by stroke showed tangible therapeutic improvement following transplantation of these cells. None of the mice formed tumors, which had been a major setback in prior attempts at stem cell transplantation.

The team was led by Stuart A. Lipton, M.D., Ph.D., professor and director of the Del E. Webb Neuroscience, Aging, and Stem Cell Research Center at Burnham. Dr. Lipton is also a clinical neurologist who treats patients with these disorders. Collaborators included investigators from The Scripps Research Institute.

Dr. Lipton induced ES cells to express a protein, discovered in his laboratory called myocyte enhancer factor 2C (MEF2C). MEF2C is a transcription factor that turns on specific genes which then drive stem cells to become nerve cells. Using MEF2C, the researchers created colonies of pure neuronal progenitor cells, a stage of development that occurs before becoming a nerve cell, with no tumors. These cells were then transplanted into the brain and later became adult nerve cells. MEF2C also protected the cells from apoptosis once inside the brain.

Dr. Lipton’s investigative team then showed that the new nerve cells, derived from the stem cells, could send and receive proper electrical signals to the rest of the brain. They found that the mice that received the transplants showed significant behavioral improvements, although their performance did not reach that of the non-stroke control mice.

These results suggest that MEF2C expression in the transplanted cells was a significant factor in reducing the stroke-induced deficits.

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