Addition of SIS3 attenuates the effects of TGF-β1 by reducing the transcriptional activity. SIS3 also inhibits the myofibroblast differentiation of fibroblasts by TGF-β1. SIS3 completely diminishes the constitutive phosphorylation of Smad3 as well as the up-regulated type I collagen expression in scleroderma fibroblasts, thus abolishes the ECM overexpression in the TGF-β1-treated normal dermal fibroblasts and scleroderma fibroblasts in vitro.
体内研究:SIS3 inhibits Smad3 activation in streptozotocin(STZ)-induced diabetic nephropathy in Tie2-Cre;Loxp-EGFP mice. It also reduces AGE-induced EndoMT and decreases EndoMT in STZ-induced diabetic nephropathy in Tie2-Cre;Loxp-EGFP mice. SIS3 significantly reduces collagen IV and fibronectin expression in the glomeruli and tubulointerstitium of STZ-injected Tie2-Cre;Loxp-EGFP mice, suggesting that SIS3 retards the early development of STZ-induced diabetic glomerulosclerosis and tubulointerstitial fibrosis. However, SIS3 administration does not reduce proteinuria.