The authors purified neural progenitors from the subventricular zones of newborn rats, and cultured them in the presence of fibroblast growth factor 2 (FGF-2) to prevent them from differentiating. The progenitor cells migrate up gradients of VEGF, in a chemotactic response specifically mediated by VEGF receptor 2. In cocultures in three-dimensional collagen matrices, the progenitors migrate toward VEGF-secreting cells. Progenitor cells that are allowed to differentiate into neuron- or glia- restricted lineages become insensitive to VEGF.
The data suggest that VEGF links angiogenesis to neurogenesis to establish neurogenic niches within the developing brain. Once the niches are established by immature progenitors, they could act as launching points for migrations by more differentiated cells. VEGF and FGF-2 might be useful in treating brain injuries by directing transplanted progenitor cells to migrate into damaged areas. ▪