Pharmacological inhibition of p300 ameliorates steatosis, inflammation, and fibrosis in mice with non-alcoholic steatohepatitis.

The histone acetyltransferase p300 plays a pivotal role in regulating gene expression and cellular phenotype through epigenetic mechanisms. It significantly influences lipid metabolism, which is a key factor in the pathogenesis of non-alcoholic steatohepatitis (NASH), by modulating the transcription of genes involved in lipid synthesis and accumulation. This study aimed to investigate the protective potential of inhibiting p300 in NASH. Male C57BL/6J mice were subjected to a methionine- and choline-deficient (MCD) diet for 4 weeks to induce NASH, and during this period, the p300 inhibitor C646 (10 mg/kg) was administered three times a week. C646 treatment reduced the elevation of p300 expression and histone H3 acetylation, leading to a decrease in liver injury markers in the serum and an improvement in the histological abnormalities observed in MCD diet-fed mice. C646 also reduced lipid accumulation by modulating de novo lipogenesis and suppressed inflammation, including cytokine overproduction and macrophage infiltration. Furthermore, C646 mitigated liver fibrosis and myofibroblast accumulation. This protective effect was achieved through the inhibition of apoptosis by reducing p53 and Bax expression and the suppression of ferroptosis by decreasing lipid peroxidation while enhancing antioxidant defenses. Additionally, C646 alleviated endoplasmic reticulum stress, as evidenced by the downregulation of unfolded protein response signaling molecules. These results highlight the potential of p300 as a therapeutic target for NASH.