SMAD4 and Hepatic fibrosis: MicroRNA-34a-5p and microRNA-618 can downregulate the expression of Col I and α-SMA in HSCs and alleviate liver fibrosis by targeting SMAD4 in the TGF-β/SMAD signaling pathway, which suggests that the interaction between microRNA and TGF-β/SMAD also plays a role in HSCs activation113, 114.