PRODUCTION OF TRANSFORMING GROWTH-FACTOR-BETA BY CULTURED RAT MESANGIAL CELLS

The purpose of this study was to examine whether transforming growth f actor-beta (TGF beta) acts as an autocrine cytokine in cultured mesang ial cells, Measangial cell conditioned media (CM) were prepared and te sted for their effect on mesangial cell proliferation. CM showed a con centration dependent inhibition on mesangial cell proliferation and th e activity was enhanced by treating conditioned media with acid, Gel f iltration analysis showed peak inhibitory activity to reside in fracti ons with an estimated molecular weight range of 16-30 KD. The activity was partially blocked by anti-TGF beta antibody, but not nonimmune co ntrol IgG, The presence of TGF beta was confirmed using the mink lung epithelial cell assay. Furthermore, the addition of anti-TGF beta anti body directly into culture media significantly enhanced mesangial cell proliferation. These results demonstrate that measangial cell produce both active and latent forms of TGF beta, which functions as an autoc rine growth inhibitor for mesangial cells.