Copper restoration by liver Ceruloplasmin ablation ameliorates NAFLD via SCO1-AMPK-LKB1 complex

Abstract

Copper is an essential nutrient and a co-factor of numerous enzymes governing a wide range of intracellular processes. Copper deficiency has emerged to be associated with various lipid metabolism diseases, including non-alcoholic fatty liver disease (NAFLD). However, the molecular mechanisms of how copper regulates lipid metabolism and is sensed remain elusive. Here, we reveal that copper elevation caused by hepatic ceruloplasmin (CP) ablation enhances lipid catabolism by promoting the assembly of copper-load SCO1/AMPK complex. We report that overnutrition-mediated CP elevation results in hepatic copper loss, and that liver-specific CP ablation counteracts this reduction in copper levels and ameliorates NAFLD in mice. Mechanistically, SCO1 constitutively interacts with LKB1 even in the absence of copper, and copper-loaded SCO1 directly tethers LKB1 to AMPK, thereby activating AMPK and consequently promoting mitochondrial biogenesis and fatty acid oxidation in hepatocytes. Therefore, this study reveals an unexpected role for AMPK to sense copper alteration via SCO1 and uncovers a previously unidentified mechanism by which copper, as a signaling molecule, improves hepatic lipid catabolism, and indicates that targeting copper-AMPK signaling pathway ameliorates NAFLD development by modulating AMPK activity.