Masson’s trichrome and Sirius Red staining showed severe renal fibrosis in UUO mice (Fig. 1c-f), and as expected, the protein levels of fibronectin, collagen I (Col I), and α-SMA in the kidneys were markedly increased in UUO mice compared to those of normal mice (Fig. 1a, b). Here, FN1 is linked to renal fibrosis.