The identification of neuronal stem cells within the adult brain has revolutionized our thinking about the fate of mature neurons. Under certain conditions, these stem cell precursors can become neurons, which were previously thought to be irreplaceable in the adult brain.
In this issue (Nature Neuroscience, Vol. 4, No. 6, 01 Jun 2001), Cattaneo and colleagues have identified the molecular switch that initiates the cascade of events that transforms these immature stem cells into functional neurons. Their key observation was that immature stem cells differ from mature neurons in that they express different forms of the Shc adaptor protein -- a protein that links growth factor signals to the cellular machinery responsible for changing the overall function of the cell. ShcA is expressed in stem cells, while ShcC is expressed in mature neurons. ShcA was previously known to be involved in maintaining the cell divisions required to continually replenish the stem cell pool. The authors now show that the switch from ShcA to ShcC promotes survival of new neurons and induces the expression of other proteins necessary for the transformation of these precursor cells into functional neurons. The next step will be to understand what causes the change in expression from ShcA to ShcC. Defining the molecules and processes that are involved in the maturation of stem cells into neurons is crucial to the development of strategies to use stem cells for the treatment of neurodegenerative diseases and traumatic injury to the nervous system.
Dr. Elena Cattaneo
Institute of Pharmacological Sciences
University of Milan
Via Balzaretti 9
tel: +39 02 20488349
fax: +39 02 29404961
(C) Nature Neuroscience press release.
Message posted by: Trevor M. D'Souza