TGFB1 and renal fibrosis: Furthermore, TRPV1 activation upregulates TGF-β1 protein expression and can inhibit the TGF-β1 fibrogenic activity by downregulating SMAD2/3; these data suggest that TRPV1 inhibits the TGF- β/SMAD signaling pathway and plays a protective role in renal fibrosis induced by salt-sensitive hypertension (Wang and Wang, 2011).