Potential of Muller glia to become neurogenic retinal progenitor cells

The possibility of neural regeneration has gained credence with the identification of neural stem cells seeded within different regions of the adult central nervous system (CNS). Recently, this possibility has received an additional boost from reports that glia, the support cells of the CNS, might provide a source of neural regeneration. We review some of our findings that Muller glia in the chicken retina are a source of proliferating progenitors that can generate neurons. These Muller cells are fully differentiated glial cells that serve functions ascribed to this cell type. In response to damage or exogenous growth factors, Muller glia dedifferentiate, proliferate, express combinations of transcription factors normally expressed by embryonic retinal progenitors, and produce new 'neurons and glia. In light of these data, the potential of Muller glia as a source of neural regeneration in the retina of nonavian species, namely humans, seems an avenue of investigation that warrants serious consideration. (C) 2003 Wiley-Liss, Inc.