Transforming growth factor-β1 and -β2 promote neurite sprouting and elongation of cultured rat hippocampal neurons

Abstract

Transforming growth factor-β (TGF-β) is known as a potent regulator of cell proliferation and differentiation. In the present study, we investigated the effects of TGF-β1 and -β2 on the survival, neurite sprouting and process elongation of primary cultured hippocampal neurons obtained from rat embryos. Addition of TGF-β1 little affected the total number of surviving neurons, but clearly increased the number of neurons bearing processes, indicating that TGF-β1 promotes neurite sprouting rather than neuronal survival. Furthermore, TGF-β1 significantly promoted the elongation of axon-like processes, but did not affect the process branching and the number of dendrite-like processes. TGF-β2 also promoted the neurite sprouting and stimulated the elongation of axons without affecting the branching. The effects of TGF-β2 were very similar to those of TGF-β1 in terms of both effective concentrations (0.1–1 ng/ml) and maximal effects. It is possible that TGF-β1 and -β2 play roles in the formation of neuritic networks in the central nervous system.