TGF-beta signal transduction and mesangial cell fibrogenesis.

Transforming growth factor-beta (TGF-beta) is closely associated with progressive renal fibrosis. Significant progress has been accomplished in determining the cellular signaling pathways that are activated by TGF-beta. This knowledge is being applied to glomerular mesangial cell models of extracellular matrix (ECM) accumulation. A central component of TGF-beta-stimulated mesangial cell fibrogenesis is the TGF-beta family-specific Smad signal transduction pathway. However, while Smads play an important role in collagen accumulation, recent findings indicate that cross talk among a variety of pathways is necessary for maximal stimulation of collagen expression. Further investigation of these multiple interactions will provide insight into possible ways to interrupt cellular mechanisms of glomerular fibrogenesis.