Growth Factors 2011[Oct]; 29 (5): 196-202 PMID21740331show ga
Transforming growth factor ? (TGF-?) is a central mediator of fibrogenesis. TGF-? is upregulated and activated in fibrotic diseases and modulates fibroblast phenotype and function, inducing myofibroblast transdifferentiation while promoting matrix preservation. Studies in a wide range of experimental models have demonstrated the involvement of the canonical ALK5/Smad3 pathway in fibrosis. Smad-independent pathways may regulate Smad activation and, under certain conditions, may directly transduce fibrogenic signals. The profibrotic actions of TGF-? are mediated, at least in part, through induction of its downstream effector, Connective Tissue Growth Factor. In light of its essential role in the pathogenesis of fibrosis, TGF-? has emerged as an attractive therapeutic target. However, the pleiotropic and multifunctional effects of TGF-? and its role in tissue homeostasis, immunity and cell proliferation raise concerns regarding potential side effects that may be caused by TGF-? blockade. This minireview summarizes the role of TGF-? signaling pathways in the fibrotic response.