Biphasic effects of exogenous VEGF on VEGF expression of adult neural progenitors.

Vascular endothelial growth factor (VEGF) regulates neurogenesis. The present study investigated the direct effect of VEGF on the enhancement of proliferation and differentiation of the adult mouse subventricular zone (SVZ) neural progenitors in vitro. A high dose (500 ng/ml) of VEGF significantly downregulated endogenous VEGF receptors 1 and 2, which was associated with significantly reduced neural progenitor cell proliferation and enhancement of neuronal differentiation. A low dose (50 ng/ml) of VEGF significantly upregulated endogenous VEGF receptors 1 and 2 but did not increase proliferation and differentiation. These data suggest that exogenous VEGF has a biphasic effect on the expression of endogenous VEGF receptors, and the high dose of VEGF enhances adult neural progenitor cell differentiation into neurons.