The role of TGF-beta signaling in the pathogenesis of fibrosis in scleroderma.

Excessive extracellular matrix (ECM) deposition in the skin, lung, and other organs is a hallmark of systemic sclerosis (SSc). The pathogenesis of SSc is still poorly understood, but increasing evidence suggests that transforming growth factor (TGF)-beta is a key mediator of tissue fibrosis as a consequence of ECM accumulation in pathological states such as systemic sclerosis. TGF-beta regulates diverse biological activities including cell growth, cell death or apoptosis, cell differentiation, and ECM synthesis. TGF-beta is known to induce the expression of ECM proteins in mesenchymal cells and to stimulate the production of protease inhibitors that prevent enzymatic breakdown of the ECM. This review focuses on the possible role of TGF-beta in the pathogenesis of fibrosis in SSc.