In cell signalling, (i) miR-155 is located upstream of ROS, since miR-155 was reported to induce ROS generation through downregulation of antioxidation-related genes, such as Nfe2l2, Sod1, and Hmox1 in mesenchymal stem cells obtained from 18-month-old mice [17] and (ii) miR-155 promotes liver fibrosis and steatohepatitis, and profibrotic genes were inhibited in miR-155 knockout mice treated with hepatotoxic agents, such as alcohol and carbon tetrachloride [16]. The gene discussed is SOD1; the disease is Hepatic fibrosis.