Inhibition of miR-320 alleviates hepatic steatosis and dyslipidemia via suppressing the transcription of APOE in MASLD

BACKGROUND: Metabolic dysfunction-associated steatotic liver disease (MASLD) is characterized by hepatic steatosis with cardiometabolic disorders. Due to the complicated pathophysiological processes, current therapeutic strategies for MASLD remain limited. Previous studies revealed that miR-320 was a regulator of systemic lipid metabolism with multi-targets. However, whether treatments against miR-320 would be benefit to MASLD was unclear. METHODS: Mice with MASLD were induced by high-fat diet (HFD) treatment. Tough Decoy or sponge against miR-320 was delivered by recombinant adeno-associated virus (serotype 8) vectors in vivo. Hepatic steatosis and plasma lipids were assessed by histopathology, biochemical assays and LC-MS. Moreover, LC-MS, Western blotting, real-time PCR, immunofluorescence and luciferase reporter were performed to investigate the underlying mechanisms. RESULTS: Knockdown of miR-320 attenuated HFD-induced MASLD by alleviating hepatic lipid accumulation and hyperlipidemia. Mechanistically, palmitic acid (PA) combined with oleic acid (OA) treatment promoted the translocation of miR-320 from the cytoplasm into the nucleus of hepatocytes. Especially, increased nuclear miR-320 activated the transcription of APOE by targeting its promoter, which in turn aggravated triglyceride accumulation and secretion in hepatocytes. CONCLUSIONS: Our study revealed that treatments against miR-320 attenuated hepatic steatosis and hyperlipidemia simultaneously, which might be a potential strategy of MASLD.