SOX9 Overexpression Ameliorates Metabolic Dysfunction-associated Steatohepatitis Through Activation of the AMPK Pathway.

Background and aims: The transcription factor sex-determining region Y-related high-mobility group-box gene 9 (SOX9) plays a critical role in organ development. Although SOX9 has been implicated in regulating lipid metabolism in vitro, its specific role in metabolic dysfunction-associated steatohepatitis (MASH) remains poorly understood. This study aimed to investigate the role of SOX9 in MASH pathogenesis and explored the underlying mechanisms.

Methods: MASH models were established using mice fed either a methionine- and choline-deficient (MCD) diet or a high-fat, high-fructose diet. To evaluate the effects of SOX9, hepatocyte-specific SOX9 deletion or overexpression was performed. Lipidomic analyses were conducted to assess how SOX9 influences hepatic lipid metabolism. RNA sequencing was employed to identify pathways modulated by SOX9 during MASH progression. To elucidate the mechanism further, HepG2 cells were treated with an adenosine monophosphate-activated protein kinase (AMPK) inhibitor to test whether SOX9 acts via AMPK activation.

Results: SOX9 expression was significantly elevated in hepatocytes of MASH mice. Hepatocyte-specific SOX9 deletion exacerbated MCD-induced MASH, whereas overexpression of SOX9 mitigated high-fat, high-fructose-induced MASH. Lipidomic and RNA sequencing analyses revealed that SOX9 suppresses the expression of genes associated with lipid metabolism, inflammation, and fibrosis in MCD-fed mice. Furthermore, SOX9 deletion inhibited AMPK pathway activation, while SOX9 overexpression enhanced it. Notably, administration of an AMPK inhibitor negated the protective effects of SOX9 overexpression, leading to increased lipid accumulation in HepG2 cells.

Conclusions: Our findings demonstrate that SOX9 overexpression alleviates hepatic lipid accumulation in MASH by activating the AMPK pathway. These results highlight SOX9 as a promising therapeutic target for treating MASH.