Gliogenesis in the central nervous system

Multipotential neuroepithelial stem cells are thought to give rise to all t he differentiated cells of the central nervous system (CNS). The developmen tal potential of these multipotent stem cells becomes more restricted as th ey differentiate into progressively more committed cells and ultimately int o mature neurons and glia. In studying gliogenesis, the optic nerve and spi nal cord have become invaluable models and the progressive stages of differ entiation are being clarified. Multiple classes of glial precursors termed glial restricted precursors (GRP), oligospheres, oligodendrocyte-type2 astr ocyte (O-2A) and astrocyte precursor cells (APC) have been identified. Simi lar classes of precursor cells can be isolated from human neural stem cell cultures and from embryonic stem (ES) cell cultures providing a non-fetal s ource of such cells. In this review, we discuss gliogenesis, glial stem cel ls, putative relationships of these cells to each other, factors implicated in gliogenesis, and therapeutic applications of glial precursors. GLIA 30: 105-121, 2000. (C) 2000 Wiley-Liss, Inc.