Targeting MDM2 for its ubiquitin-proteasome degradation: Curcumenol from turmeric ameliorates NAFLD through p53-AMPK-PGC-1α-activated mitochondrial biogenesis

Non-alcoholic fatty liver disease (NAFLD) is a growing global health concern with no approved pharmacotherapy. Curcumenol (Cul), a bioactive sesquiterpenoid derived from the well-known functional food turmeric (Curcuma longa), shows potential therapeutic effects in treating metabolic diseases. In this study, we demonstrated that Cul significantly ameliorated high-fat diet-induced NAFLD accompanied by obesity and hyperlipidemia in mice via promoting lipid oxidative metabolism and inhibiting de novo lipogenesis. In palmitic acid/oleic acid (PA/OA)-treated AML12 hepatocytes, Cul markedly reduced intracellular lipid accumulation, oxidative stress, and inflammation. Through an integrative approach combining network pharmacology, molecular docking, molecular dynamics simulation, cellular thermal shift assay (CETSA), surface plasmon resonance (SPR), immunoprecipitation (IP), and plasmid-based overexpression techniques, we demonstrated that Cul directly interacted with MDM2 protein, inducing its degradation via the ubiquitin-proteasome system, which led to p53 stabilization and subsequent activation of the AMPK-PGC-1α signaling axis. This cascade enhanced mitochondrial biogenesis and fatty acid β-oxidation, thereby ameliorating hepatic steatosis in PA/OA-induced AML12 cells. Additionally, Cul suppressed de novo lipogenesis, contributing to its anti-NAFLD effects. Collectively, this study innovatively unveils MDM2 as a novel therapeutic target for NAFLD and demonstrates that Cul is the first sesquiterpenoid component capable of inducing MDM2 degradation via the ubiquitin-proteasomal pathway, representing a new mechanistic strategy for metabolic disease treatment.