Exploring the potential mechanisms of chrysophanol in the treatment of nonalcoholic fatty liver disease based on network pharmacology and experimental validation

Background Nonalcoholic fatty liver disease (NAFLD) is a chronic liver disease characterized by abnormal lipid accumulation. Chrysophanol (CHR), a major active compound of zexie decoction combined with erchen decoction (ZXD-ECD), exhibits therapeutic effects on NAFLD, but its mechanism of action remains unclear. Therefore, this study aims to explore the potential mechanisms of CHR in ameliorating NAFLD. Methods Gene expression omnibus (GEO) was used to download NAFLD-related datasets. Differential expression and weighted gene co-expression network analysis (WGCNA) identified NAFLD-associated targets. Cytoscape 3.0 was used to visualize networks. Search tool for the retrieval of interacting genes (STRING) was applied for gene ontology (GO) and kyoto encyclopedia of genes and genomes (KEGG) enrichment analyses. PubChem provided compound structures. Cell counting kit-8 (CCK-8) and western blot assessed cell viability and protein levels. Roche kits measured triglyceride (TG) and total cholesterol (TC). Flow cytometry evaluated apoptosis. Free fatty acid (FFA) kits measured FFA levels. Results The GSE89632 dataset showed significant differences, and WGCNA identified the brown module as highly correlated with NAFLD. Protein-protein interaction (PPI) analysis revealed strong interactions among brown module genes. GO and KEGG enrichment highlighted positive regulation of apoptotic process and tumor necrosis factor (TNF) signaling pathway. NAFLD targets significantly overlapped with the main active compounds of ZXD-ECD. Intersecting brown module genes with chrysophanol (CHR) targets identified proviral integration site for Moloney murine leukemia virus 1 (PIM1) as a potential key target gene, which was downregulated in GSE89632 ( P < 0.05). CHR treatment increased cell viability and PIM1 expression in NAFLD cell models ( P < 0.05). P IM1 knockdown elevated TG and TC levels ( P < 0.05), upregulated fatty acid synthase (FAS) ( P < 0.05), stearoyl-CoA desaturase 1 (SCD1) ( P < 0.05), sterol regulatory element-binding protein 1 (SREBP1) ( P < 0.05), and increased apoptosis ( P < 0.05). These findings were confirmed in NAFLD animal models, and PIM1 knockdown also increased FFA levels ( P < 0.05). Conclusion CHR upregulates PIM1 expression and alleviates NAFLD, offering a new perspective to explore its molecular mechanism.