TGFβ1 Modulates the Phenotype of Schwann Cells at the Transcriptional Level

We have examined the effects of transforming growth factor β1 (TGFβ1) on gene expression in cultured rat Schwann cells (SCs). TGFβ1 decreased the steady-state mRNA levels of several genes that are expressed by myelinating SCs but had varied effects on the mRNA levels of NCAM, L1, GAP-43, and p75—genes that are expressed by denervated and nonmyelinating SCs. TGFβ1 antagonized the effects of forskolin on the mRNA levels of the transcription factors Oct-6/tst-1/SCIP and Krox20. Transcriptional run-off analysis demonstrated that the effects of TGFβ1 on gene expression occur at least in part at the level of transcription. Thus, TGFβ1 suppresses the expression of genes that characterize the different phenotypes of SCs, and these changes occur at least in part at a transcriptional level.