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NY Times May 22, 2001 "Switch" That Turns Stem Cells to Neurons Found By REUTERS Filed at 5:20 p.m. ET NEW YORK (Reuters Health) - Researchers in Italy have discovered a molecular switch that tells immature brain cells to become fully developed neurons. The discovery may lead to advances in using brain stem cells to treat neurological diseases such as Parkinson's and Alzheimer's that destroy neurons, the study's lead author told Reuters Health. Stem cells are immature cells that develop into more advanced cells. And neural stem cells have the potential to replace neurons lost to disease, according to Dr. Elena Cattaneo of the University of Milan. The idea is to take a small number of neural stem cells, let them multiply in the laboratory and then transplant them into the brain, where they will form neurons, she explained. ``But making a lot of neurons from stem cells is not that simple,'' she said. Several animal studies have shown that once neural stem cells are transplanted, they generate large numbers of another type of brain cell called glial cells, not the neurons that are needed, Cattaneo said. To solve this problem, Cattaneo and her colleagues set out to discover the ``intracellular triggers'' that instruct neural stem cells to become neurons instead of glial cells. The researchers focused on several molecules called Shc adapters, which ``sense'' a cell's surroundings. There are three known Shc adapters: ShcA, ShcB and ShcC. ``We found that immature neural stem cells express ShcA only, and that its presence is important for their division,'' Cattaneo told Reuters Health. In contrast, the investigators found that mature neurons express only ShcC, not ShcA. Cattaneo's team also observed that during the transition from stem cells to neurons, there was a ''remarkable switch'' from ShcA to ShcC. ``We indicate that ShcC is a molecular trigger that tells the neural stem cells to become neurons,'' Cattaneo said. The research also indicates that the presence of ShcC is essential for the survival of neurons, she said. ``Therefore, if we want to make more neurons out of stem cells, and if we want to keep those neurons alive, we know on which precise molecule to act,'' Cattaneo explained. The findings may have implications for the therapeutic use of neural stem cells, according to the Italian researcher. It may be possible, for example, to make stem cells express ShcC, she said. In addition, if researchers find drugs that help maintain ShcC activity in neurons, it may be possible to help neurons survive longer, she said. SOURCE: Nature Neuroscience 2001;4:579-586. http://www.nytimes.com/reuters/health/health-stemcells.html?searchpv=reuters ************** ---------------------------------------------------------------------- To sign-off Parkinsn send a message to: mailto:[log in to unmask] In the body of the message put: signoff parkinsn