Environmental enhancement of growth factor-mediated oligodendrocyte precursor proliferation.

The timing of oligodendrogenesis depends on the specific location within the central nervous system, suggesting the local environment influences oligodendrocyte precursor proliferation. Spinal cord and optic nerve oligodendrocyte precursors both proliferate in response to platelet-derived growth factor (PDGF). Here we show that neurotrophin-3 (NT-3) enhanced PDGF-induced proliferation of optic nerve oligodendrocyte precursors, and these cells were labeled by an anti-trkC antibody. By contrast, NT-3 did not enhance PDGF-induced proliferation of spinal cord oligodendrocyte precursors, and these cells were not labeled by an anti-trkC antibody. Furthermore, PDGF-induced oligodendrocyte precursor proliferation was greater in spinal cord than in optic nerve cultures. The difference in NT-3 response between spinal cord and optic nerve oligodendrocyte precursors appears cell intrinsic, while the enhanced PDGF-induced proliferation of spinal cord oligodendrocyte precursors appears environmentally regulated. The spinal cord PDGF proliferation-enhancing activity may provide a mechanism to allow temporal and spatial regulation of gliogenesis.