Transforming growth factor-beta-3 is mitogenic for rat retinal progenitor cells in vitro

Recent data indicate that the process of neurogenesis in the mammalian central nervous system (CNS) may be regulated by peptide growth factors, such as epidermal growth factor, transforming growth factor-alpha, and acidic or basic fibroblast growth factor. We have investigated whether members of the transforming growth factor-beta (TGF beta) family also play a role in this process and have found that TGF beta-3 is mitogenic for embryonic rat retinal cells in vitro. We also show that TGF beta-3 stimulates production of retinal amacrine cells while photoreceptor production remains unchanged. These data demonstrate that TGF beta-3 can regulate cell proliferation in the CNS during development and can also influence commitment or differentiation, or both, of neural progenitor cells to particular retinal fates.