TGF-beta 1, beta 2, beta 1.2 and the bone morphogenetic protein BMP2: members of the transforming growth factor type beta supergene family with different morphogenetic effects on rat astrocyte cultures.

The transforming growth factors type beta (TGF-beta) are immunoregulatory cytokines with pronounced effects on tissue homeostasis and repair. We observed that TGF-beta 1, TGF-beta 2, and the heterodimeric TGF-beta 1.2 induced astrocyte hyperplasia and strongly affected monolayer formation. After confluent growth, astrocytes are contact inhibited and form a dense monolayer. Addition of TGF-beta induced migration of cells to local centers, the formation of foci, followed by detachment of these aggregates from the cell culture surface. This effect was unique and could neither be induced by BMP2, a member of the decapentaplegic subfamily of type beta transforming growth factors nor by other cytokines or interleukins. Thus TGF-beta secreted by activated leukocytes might be a local regulator of astrocyte function during regenerative processes in inflammatory demyelinating brain disease.