INSR and renal fibrosis: In addition, Erbb4-IR can also target Smad7, and specific silencing of Erbb4-IR expression up-regulates Smad7 in the kidneys, thereby attenuating TGF-β1/Smad3-induced renal fibrosis in vivo and in vitro (Gu et al., 2020a; Xia W. et al., 2021).