Anti-fibrotic action of pirfenidone in Dupuytren's disease-derived fibroblasts.

BACKGROUND: Dupuytren's disease (DD) is a complex fibro-proliferative disorder of the hand that is often progressive and eventually can cause contractures of the affected fingers. Transforming growth factor beta (TGF-ß1) has been implicated as a key stimulator of myofibroblast activity and fascial contraction in DD. Pirfenidone (PFD) is an active small molecule shown to inhibit TGF-ß1-mediated action in other fibrotic disorders. This study investigates the efficacy of PFD in vitro in inhibiting TGF-ß1-mediated cellular functions leading to Dupuytren's fibrosis. METHODS: Fibroblasts harvested from (DD) and carpal tunnel (CT)- tissues were treated with or without TGF-ß1 and/or PFD and were subjected to cell migration, cell proliferation and cell contraction assays. ELISA; western blots and real time RT-PCR assays were performed to determine the levels of fibronectin; p-Smad2/Smad3; alpha-smooth muscle actin (α-SMA), α2 chain of type I collagen and α1 chain of type III collagen respectively. RESULTS: Our results show that PFD effectively inhibits TGF-ß1-induced cell migration, proliferation and cell contractile properties of both CT- and DD-derived fibroblasts. TGF-ß1-induced α-SMA mRNA and protein levels were inhibited at the higher concentration of PFD (800 µg/ml). Interestingly, TGF-ß1 induction of type I and type III collagens and fibronectin was inhibited by PFD in both CT- and DD- derived fibroblasts, but the effect was more prominent in DD cells. PFD down-regulated TGF-ß1-induced phosphorylation of Smad2/Smad3, a key factor in the TGF-ß1 signaling pathway. CONCLUSION: Taken together these results suggest the PFD can potentially prevent TGF-ß1-induced fibroblast to myofibroblast transformation and inhibit ECM production mainly Type I- and Type III- collagen and fibronectin in DD-derived fibroblasts. Further in-vivo studies with PFD may lead to a novel therapeutic application in preventing the progression or recurrence of Dupuytren's disease.