Differentiation and maturation of astrocytes derived from neuroepithelial progenitor cells in culture

Neuroepithelial progenitor cells from striata of adult mice develop into either astrocytes or neurons when cultured in the presence of epidermal growth factor (B. A. Reynolds, and S. Weiss, Science 255: 1707-1710, 1992). We instituted primary cultures of such progenitor cells from forebrains of newborn rat pups in an epidermal growth factor-containing medium free of serum in order to study the development of astrocytes in culture. At 4-6 days, primary cultures consisted of floating clusters of proliferating cells which expressed nestin, a marker for neuroepithelial progenitor cells, the ganglioside GD3, and vimentin. When clusters were transferred to polylysine-coated dishes, cells attached to the substrate and began to express antigens characteristic of particular differentiated neurons, astrocytes, or oligodendrocytes within 2 weeks. In 4- to 6-week-old secondary cultures, levels of vimentin expression appeared to decrease within maturing astrocytes which had increased levels of glial fibrillary acidic protein. These results suggest that multipotential epidermal growth factor-progenitor cells can give rise to both neurons and macroglia of the adult central nervous system, and that maturation of the astrocytes in vitro may be occurring in a pattern similar to that seen in vivo . Furthermore, no glial fibrillary acidic protein-positive cells expressed the A₂B₅ antigen in the same cell indicating an absence of type-2 astrocytes.