Our data showed that GS-HCl effectively inhibited up-regulation of α-SMA, collagen I, and fibronectin in the TGF-β1-treated renal epithelial cells (Fig. 3) and mouse UUO kidneys (Fig. 2), thereby leading to amelioration of renal fibrosis (Fig. 1). Here, TGFB1 is linked to renal fibrosis.