Probiotic YH-15 ameliorates diet-induced obesity and hepatic steatosis associated with bile acid remodeling and TGR5/PPARδ-linked signaling

Obesity and hepatic steatosis are closely associated with dysregulated gut microbiota and bile acid metabolism. This study evaluated the metabolic effects of Pediococcus acidilactici YH-15 in a high-fat diet (HFD)-induced obese mouse model using integrated multi-omics analyses. YH-15 supplementation significantly reduced weight gain, improved lipid profiles, and alleviated hepatic steatosis. Multi-omics data revealed coordinated remodeling of gut microbiota, bile acid composition, and hepatic metabolic pathways, characterized by enrichment of Lachnospiraceae and increased taurocholic acid (TCA) levels. In AML12 hepatocytes, TCA increased TGR5 fluorescence intensity, promoted PPARδ nuclear localization, and upregulated lipid catabolic proteins, including ATGL and CPT1A, whereas these responses were attenuated by TGR5 inhibition. These findings associate YH-15 treatment with coordinated microbiota and bile acid remodeling and support a possible role for TGR5/PPARδ-associated signaling in the hepatic metabolic response.