Natural molecule isoliquiritigenin mitigates MASH and liver fibrosis in mice by promoting autophagy through the PI3K/Akt signaling pathway

Isoliquiritigenin (ISL), a flavonoid derived from licorice root, has diverse biological and pharmacological properties. This study aimed to investigate the hepatoprotective effects and mechanism of action of ISL on the pathogenesis of metabolic dysfunction-associated steatohepatitis (MASH). C57BL/6 mice fed a chow diet or choline-deficient, L-amino acid-defined, high-fat diet (CDAHFD) received ISL (10 mg/kg) or vehicle daily via oral administration. To further explore the mechanism of ISL in MASH pathogenesis, AML12 cells were exposed to palmitic acid (PA) as an in vitro model of lipid toxicity. The results showed that, compared with vehicle-treated mice, ISL treatment alleviated liver injury, steatosis, inflammation, and fibrosis in MASH mice. Moreover, ISL treatment reduced the recruitment of CD68⁺ macrophages and activated hepatic stellate cells (HSCs) in MASH livers. In vitro experiments showed that ISL reduced lipid accumulation and mitigated inflammatory responses in PA-induced AML12 cells. Notably, RNA-sequencing analyses revealed that the anti-MASH effect of ISL enhanced autophagy via the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signaling pathway. This was further validated by assessing autophagy markers in both MASH liver tissues and PA-stimulated AML12 cells in vitro. Additionally, molecular docking analysis demonstrated that the target proteins of ISL exhibited strong binding affinity to PIK3 isoforms. In conclusion, our findings highlight that ISL mitigates MASH and fibrosis in mice by promoting autophagy through the PI3K/Akt/mTOR signaling pathway, providing reliable evidence to support further studies on MASH in humans.