1630-P: β-hydroxybutyrate Enhances Hadha β-hydroxybutyrylation to Alleviate Mitochondrial Dysfunction and Hepatic Steatosis in MASLD

Introduction and Objective: Over the past three decades, the global prevalence of MASLD has rapidly increased, leading significant economic and clinical burdens. Our previous study demonstrated that a 2-week ketogenic diet (KD) effectively treated hepatic steatosis in MASLD mice, largely due to elevated levels of β-hydroxybutyrate (β-OHB). This study aims to investigate the therapeutic effects of β-OHB on MASLD mice and elucidate the underlying mechanisms. Methods: MASLD mouse model was generated by feeding mice a 12-week high-fat diet (HFD). Liver injury, hepatic lipid accumulation and pan-β-hydroxybutyrylation (Kbhb) levels were assessed in vivo and in vitro. The effect of β-OHB on lipid deposition in AML-12 cells was detected by BODIPY fluorescence staining and analysis of TG/TC levels. Transmission electron microscopy assay, flow cytometry, fluorescent probe staining, and Seahorse cell energy metabolism assay were used to detect the alleviative effect of β-OHB on mitochondrial integrity and dysfunction. Kbhb-modified proteomics analysis was performed on mouse liver tissue to identify differentially modified proteins and sites. Results: β-OHB ameliorates lipid deposition and increases Kbhb levels in vivo and in vitro. In addition, β-OHB significantly improves mitochondrial dysfunction, including ROS accumulation, impaired TCA cycle and FAO function in the high-fat cell model. Kbhb proteomics analysis identified a high level of Kbhb modification at HADHA K60. Conclusion: β-OHB exhibits therapeutic effects on hepatic steatosis and mitochondrial dysfunction in MASLD mice. We uncover a novel mechanism where β-OHB enhances HADHA K60 Kbhb modification, thereby promoting the TCA cycle critical and FAO for maintaining mitochondrial homeostasis and alleviating lipid deposition. Disclosure J. Cai: None. X. Xiao: None. L. Ma: None.