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Fig. 3 | Arthritis Research & Therapy

Fig. 3

From: Macitentan inhibits the transforming growth factor-β profibrotic action, blocking the signaling mediated by the ETR/TβRI complex in systemic sclerosis dermal fibroblasts

Fig. 3

Macitentan (MAC) effects in systemic sclerosis (SSc) fibroblasts (FBs) transfected with endothelin-1 (ET-1) siRNA. a SSc FBs were transfected with specific ET-1 siRNA or nontargeting scramble scr-siRNA, and ET-1 expression was evaluated by quantitative RT-PCR. The cells transfected with ET-1 siRNA showed a decreased expression of ET-1 gene, when compared with cells transfected with scr-siRNA. The transforming growth factor beta (TGF-β) stimulus induces a significant increase in ET-1 expression in SSc FBs treated with scr-siRNA, but in SSc FBs treated with ET-1 siRNA; TGF-β was unable to induce an ET-1 increase. b Western blot of phospho-Sma and Mad Related (pSMAD)1/5, pSMAD2/3 and ET-1 proteins. In SSc FBs treated with scr-siRNA, TGF-β induced a significant increase in SMAD phosphorylation and MAC inhibited this effect. Mirroring these data, MAC inhibited the TGF-β effect in SSc FBs treated with ET-1 siRNA. In SSc FBs transfected with ET-1 siRNA, ET-1 protein was not expressed. Pictures are representative of all experiments. Protein bands were quantified by densitometry and the values are expressed as protein relative quantification/β actin relative quantification. **p = 0.0002, ***p = 0.0001. UT untreated

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