Directed mobilization of endogenous neural progenitor cells: the intersection of stem cell biology and gene therapy.

Multipotential neural stem cells, which are capable of giving rise to both neurons and glia, line the cerebral ventricles of all adult animals, including humans. These cells may be mobilized and induced to undergo neuronal differentiation in vivo, by stimulating resident progenitor cells with both delivered and virally expressed growth factors. This strategy may be particularly efficacious in striatal neurodegenerative conditions such as Huntington's disease, in which lost medium spiny striatal neurons may be replenished through directed induction of progenitor cells lining the striatal ventricular wall. More broadly, our increasing understanding of the molecular control of progenitor cell mobilization and differentiation will likely afford many new opportunities for using induced neuronal replacement as a therapeutic strategy for neurodegenerative diseases.