Bipotential precursors of putative fibrous astrocytes and oligodendrocytes in rat cerebellar cultures express distinct surface features and "neuron-like" gamma-aminobutyric acid transport.
When postnatal rat cerebellar cells were cultured in a chemically defined, serum-free medium, the only type of astrocyte (defined by the expression of the glial fibrillary acidic protein, GFAP) present was unable to accumulate gamma-[3H]aminobutyric acid (GABA), did not express surface antigens recognized by two monoclonal antibodies, A2B5 and LB1, and showed minimal proliferation. In these cultures, nonneuronal A2B5+, LB1+ stellate cells exhibiting "neuron-like" [3H]GABA uptake formed cell colonies of increasing size and were GFAP-. After about one week of culturing, the A2B5+, LB1+, GABA-uptake positive cell groups became galactocerebroside (GalCer) positive. Immunocytolysis of the A2B5+ cells at 3 and 4 days in vitro prevented the appearance of the A2B5+, LB1+, GABA-uptake positive cell colonies, and also of the GalCer+ cell groups. If 10% (vol/vol) fetal calf serum was added to 6-day cultures, the A2B5+, LB1+, GABA-uptake positive cell groups expressed GFAP and not GalCer. If the serum was added to the cultures 2 days after lysing the A2B5+ cells, only A2B5-, LB1-, GABA-uptake negative astrocytes proliferated. It is concluded that the putative fibrous astrocytes previously described in serum-containing cultures (which had a stellate shape and were A2B5+, LB1+, GABA-uptake positive) derive from bipotential precursors that differentiate into oligodendrocytes (GalCer+) in serum-free medium or into astrocytes (GFAP+) in the presence of serum, while the epithelioid A2B5-, LB1-, GABA-uptake negative astrocytes originate from a different precursor not yet identified.
D000818:Animals; D000911:Antibodies, Monoclonal; D000954:Antigens, Surface / Q000032:analysis; D001253:Astrocytes / Q000166:cytology* / Q000276:immunology / Q000378:metabolism; D002454:Cell Differentiation; D002478:Cells, Cultured; D002518:Ceramides / Q000378:metabolism; D002531:Cerebellum / Q000166:cytology; D005455:Fluorescent Antibody Technique; D005904:Glial Fibrillary Acidic Protein / Q000276:immunology; D009457:Neuroglia / Q000166:cytology*; D009836:Oligodendroglia / Q000166:cytology* / Q000276:immunology / Q000378:metabolism; D051381:Rats; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
D000911:Antibodies, Monoclonal; D000954:Antigens, Surface; D002518:Ceramides; D005904:Glial Fibrillary Acidic Protein; D005680:gamma-Aminobutyric Acid