Mitochondrial SIRT3 Activation Restores Metabolic Flexibility in Non-Alcoholic Fatty Liver Disease: Proteomic and Metabolomic Evidence

Abstract

Non-alcoholic fatty liver disease (NAFLD) is strongly associated with impaired mitochondrial metabolism and reduced metabolic flexibility. Mitochondrial sirtuins, particularly SIRT3, play essential roles in regulating oxidative metabolism through post-translational deacetylation of metabolic enzymes. The present study investigated the impact of SIRT3 activation on mitochondrial metabolic remodeling in a high-fat diet (HFD)-induced NAFLD mouse model. Thirty male C57BL/6J mice were allocated into control, HFD, and HFD plus SIRT3 activator groups. Mitochondrial respiration, proteomic acetylation profiling, and targeted metabolomic analyses were performed using Seahorse XF analysis and LC-MS/MS techniques. HFD feeding significantly reduced SIRT3 activity and impaired mitochondrial respiratory capacity, accompanied by increased mitochondrial protein hyperacetylation and accumulation of long-chain acylcarnitines. Pharmacological activation of SIRT3 partially restored mitochondrial oxidative phosphorylation, normalized acetylation status of key metabolic enzymes, and improved fatty acid oxidation. These findings suggest that restoration of SIRT3 signaling may improve mitochondrial metabolic flexibility and represent a promising therapeutic strategy for NAFLD-associated metabolic dysfunction.