Over the course of one year 7,800 individuals will develop some form of spinal cord injury (SCI) within the USA, on top of the approximate 400,000 people who already live with SCI. Medicine could help people with permanent neuronal damage by inducing new neural growth within the injured spinal cord. For this kind of treatment to be available we must first understand how the neuronal cell progenitors are maintained during development of the spinal cord. Work to be published in the June issue of Nature Cell Biology (Vol. 3, No. 6, pp. 559-566, 01 June 01) identifies what one of the signals involved in this maintenance might be.
During embryonic neural development the head (anterior) and tail (posterior) regions are specified to ensure correct development of the spinal cord. Without controlling this development, and indicating to the developing neurons whether they will be in the anterior or posterior region, spinal defects occur in the offspring. Work by Scott Fraser, of the California Institute of Technology, Pasadena, (Nature Cell Biology 3: 559-566, 2001) shows that the signalling molecule Fibroblast Growth Factor (FGF) might be involved in maintaining posterior neuronal development.
Fraser and colleagues showed that the posterior nervous system of the chicken contains a zone of renewing stem cells. This zone requires FGF to maintain proliferation of the cells in this zone. These cells will develop into posterior neural cells as the spinal cord grows. FGF can also act to transform neural development from anterior to posterior and was thought to specify posterior neuronal development.
When FGF is inhibited, the spinal cord does not elongate correctly during development. This inhibition prevents the progenitor cells in the posterior zone from being maintained and the posterior neuronal cells normally seen are abolished.
This work will lead to further understanding of how the nervous system develops and might lead to insight into how damaged neural cells can be encouraged to re-grow.
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Message posted by: Trevor M. D'Souza