Modulation of vascular cell behavior by transforming growth factors beta.

The vascular cell responses to the type 1, 2, and 3 isoforms of transforming growth factor-beta (TGF-beta 1, TGF-beta 2, TGF-beta 3) were studied using bovine aortic endothelial (BAECs) and smooth muscle cells (BASMC3) as well as rat epididymal fat pad microvascular endothelia (RFCs). Three distinct bioassays indicated that TGF-beta elicits results that do not differ significantly from those of the TGF-beta 1 isoform in all three cell populations. These assays are: inhibition of proliferation, cell migration, and neovascularization. By contrast the cellular responses to TGF-beta 1 and TGF-beta 3 differed from those to TGF-beta 2. Three distinct receptor assays revealed the presence of type I and type II TGF-beta 1 cell surface binding proteins on BAECs, BASMCs, and RFCs. Experimentation to decipher cell surface binding by the different isoforms revealed that iodinated TGF-beta 1 bound to the surface of all three vascular cell types can be competed off in similar fashion by either TGF-beta 1 or TGF-beta 3; however, competition with TGF-beta 2 produced unique binding profiles dependent on the cell type examined. The ratios of type I to type II TGF-beta receptors in these three vascular cell types vary from 1:1 in BAECs to 1.5:1 in RFCs to 3:1 in BASMCs and can be correlated with the differences noted in cellular responses to TGF-beta 1 and TGF-beta 2 in proliferation, migration, and in vitro angiogenic assays.(ABSTRACT TRUNCATED AT 250 WORDS)