SMAD3 and renal fibrosis: Although the effects of SIRT1 on Smad3 acetylation remain to be determined, resveratrol was shown to affect acetylation but not phosphorylation of Smad3 to inhibit TGF-β1-induced up-regulation of collagen IV and fibronectin mRNA levels in vitro and renal fibrosis in the model of unilateral ureteral obstruction (UUO) in vivo (62).