Xiayuxue decoction alleviates MASH by regulating gut microbiota, bile acid metabolism, and m⁶A modification

Metabolic dysfunction-associated steatohepatitis (MASH) has emerged as a worldwide health challenge with few therapeutic options. Xiayuxue Decoction (XYXD), a classical herbal formula from the Synopsis of the Golden Chamber (Jin Gui Yao Lue), a classic by Zhang Zhongjing, comprises Prunus persica (Linn.) Batsch, Rheum palmatumLinn., and Eupolyphaga sinensis Walker. While clinically employed for the treatment of chronic liver diseases, including MASH, its precise molecular mechanisms remain undefined.

This study aims to clarify the therapeutic mechanisms underlying the effects of XYXD in MASH, with a particular focus on investigating its roles in gut microbiota remodeling, bile acid (BA) metabolism, N⁶-methyladenosine (m⁶A) transcriptional modification, and arachidonic acid (AA) metabolism.

A MASH model was induced by using a methionine-choline-deficient (MCD) diet, and the therapeutic effect of XYXD was evaluated by analyzing lipid profiles, liver function parameters, and histopathological changes. Gut microbiota composition was characterized via 16S rRNA gene sequencing. Meanwhile, the metabolomic profiling of BA metabolites in the liver, serum, and feces, as well as AA derivatives in the liver, was performed by using LC-MS/MS. Additionally, the expression profiles of relevant mRNAs and proteins, including those related to BA metabolism, lipid homeostasis, inflammatory response, and m⁶A modification, were determined. Deoxycholic acid (DCA) and XYXD-containing serum were used to treat RAW264.7 macrophage cells to verify further their regulatory effects on inflammation, m⁶A modification, and AA metabolism in vitro.

XYXD exhibits therapeutic efficacy against MASH through the dual regulation of inflammatory pathways and lipid metabolic homeostasis. It effectively reverses MCD diet-induced microbiota imbalance and maintains BA homeostasis by activating the farnesoid X receptor (FXR)-small heterodimer partner (SHP) pathway, with a particular role in reducing Clostridium abundance and DCA levels. Further investigations revealed that DCA mediates the upregulation of methyltransferase-like 13/14 mRNA, which in turn enhances m⁶A modification and influences AA metabolism. This integrated regulation of inflammatory, metabolic, and epigenetic pathways underscores XYXD's systemic therapeutic potential.

XYXD alleviates MASH via the following multifaceted regulatory mechanism: it modulates gut microbiota dynamics, activates the FXR-SHP axis to maintain BA homeostasis, and ultimately regulates m⁶A transcriptional modification to influence AA metabolism. This coordinated network establishes functional crosstalk between microbiota and metabolic pathways in disease intervention.