A metabolic stress-inducible miR-34a-HNF4α pathway regulates lipid and lipoprotein metabolism

Non-alcoholic fatty liver disease (NAFLD) is one of the most common liver diseases, but its underlying mechanism is poorly understood. Here we show that hepatocyte nuclear factor 4α (HNF4α), a liver-enriched nuclear hormone receptor, is markedly inhibited, whereas miR-34a is highly induced in patients with non-alcoholic steatohepatitis, diabetic mice and mice fed a high-fat diet. miR-34a is essential for HNF4α expression and regulates triglyceride accumulation in human and murine hepatocytes. miR-34a inhibits very low-density lipoprotein secretion and promotes liver steatosis and hypolipidemia in an HNF4α-dependent manner. As a result, increased miR-34a or reduced HNF4α expression in the liver attenuates the development of atherosclerosis in Apoe−/− or Ldlr−/− mice. These data indicate that the miR-34a-HNF4α pathway is activated under common conditions of metabolic stress and may have a role in the pathogenesis of NAFLD and in regulating plasma lipoprotein metabolism. Targeting this pathway may represent a novel approach for the treatment of NAFLD. The nuclear hormone receptor HNF4α is important for liver function. Here, Xu et al.show that miR-34a regulates expression of HNF4α and is increased under conditions of metabolic stress, suggesting miR-34a promotes the development of non-alcoholic fatty liver disease.