ACTA1 and renal fibrosis: In mice with STZ-induced DN, DcR2 overexpression promoted STZ-induced renal fibrosis, as evidenced by increased expression of α-SMA and collagen I mRNA (Fig. 2B and C), expansion of the fibrotic area in Masson staining (Fig. 2D, E), increased collagen levels (Fig. 2F), and upregulated expression of fibrotic proteins (α-SMA and collagen IV, Fig. 2G–J).