protopanaxatriol and Inflammation

Metabolic associated fatty liver disease (MAFLD) is one of the most common chronic liver diseases and may develop into non-alcoholic steatohepatitis (NASH), fibrosis, cirrhosis, and even hepatocellular carcinoma, which has threatened human health. Although NLRP3 inflammasome is widely recognized in the pathogenesis of MAFLD, there are currently no drugs targeting NLRP3 inflammasome approved by regulatory agencies. Panax ginseng and its main saponin components have been used to regulate inflammatory and metabolic disorders. Notably, 20(S)-protopanaxatriol (PPT) is an active metabolite of protopanaxatriol saponins with prominent anti-inflammatory activity. However, the mechanism by which PPT ameliorates MAFLD has not been fully elucidated. Therefore, this study explored the efficacy and mechanism of PPT in treating MAFLD based on the inhibition of NLRP3 inflammasome activation. First, we screened potential NLRP3 inflammasome blockers from protopanaxadiol saponins in mouse primary bone marrow-derived macrophages (BMDMs) stimulated by LPS and different inflammasome inducers. Second, LPS-primed mouse BMDMs, mouse primary hepatocytes, mouse primary Kupffer cells and human peripheral blood mononuclear cells (PBMCs) stimulated by cholesterol and ATP were used to evaluate the effect of PPT in inhibiting NLRP3 inflammasome. Finally, MCD-induced mouse MAFLD were established to verify the therapeutic effect of PPT by inhibiting NLRP3 inflammasome. Our results showed that PPT of ginseng saponins significantly inhibited NLRP3 inflammasome activation in multiple primary cells, suppressed systemic inflammation, restored liver function, and attenuated liver inflammation as well as fibrosis in MCD--induced mouse MAFLD. Collectively, protopanaxatriol saponins metabolite PPT, may serve as a potent therapeutic agent for MAFLD by inhibiting NLRP3 inflammasome activation.

Topics: Animals; Fibrosis; Humans; Inflammasomes; Inflammation; Leukocytes, Mononuclear; Lipopolysaccharides; Mice; Mice, Inbred C57BL; NLR Family, Pyrin Domain-Containing 3 Protein; Non-alcoholic Fatty Liver Disease; Saponins

Protopanaxatriol saponin (PPT) has excellent anti-cancer, anti-diabetes, and anti-anemia effects, but its effect on intestinal bacteria has rarely been studied. In this study, we investigated whether PPT has the ability to improve intestinal health in antibiotic-treated mice. Model mice were constructed using a broad-spectrum antibiotic, cephalosporin. The composition of the gut microbiota and relative concentration of short-chain fatty acids (SCFAs), short-chain fatty acid receptor proteins (GPR41, GPR43 and GPR109A), tight junction components (ZO-1 and occludin) and pro-inflammatory cytokines (TNF-α, IL-6, IL-1β, IL-22 and IFN-γ) were determined. The results showed that PPT improved the composition of the gut microbiota, increased the concentration of SCFAs as well as receptor proteins and tight junction proteins, and decreased the pro-inflammatory cytokines. These findings indicate that PPT has a protective effect on intestinal microbes and enhances the integrity of the intestinal barrier as well as alleviates colonic inflammation in antibiotic-treated mice.

Topics: Animals; Anti-Bacterial Agents; Bacteria; Body Weight; Cephalosporins; Colon; Cytokines; Dysbiosis; Fatty Acids, Volatile; Feces; Gastrointestinal Microbiome; Inflammation; Intestines; Male; Mice; Mice, Inbred C57BL; Models, Animal; Occludin; Protective Agents; Receptors, G-Protein-Coupled; Sapogenins; Saponins; Tight Junction Proteins; Zonula Occludens-1 Protein

Obesity is prevalent worldwide, and is highly associated with metabolic disorders, such as insulin resistance, hyperlipidemia and steatosis. Ginseng has been used as food and traditional herbal medicine for the treatment of various metabolic diseases. However, the molecular mechanisms how ginseng and its components participate in the regulation of lipogenesis are still largely unclear. Here, we identified that protopanaxatriol (PPT), a major ginseng constituent, inhibited rosiglitazone-supported adipocyte differentiation of 3T3-L1 cells by repressing the expression of lipogenesis-related gene expression. In high-fat diet-induced obesity (DIO) mice, PPT reduced body weight and serum lipid levels, improved insulin resistance, as well as morphology and lipid accumulation, particular macrovesicular steatosis, in the livers. These effects were confirmed with genetically obese ob/ob mice. A reporter gene assay showed that PPT specifically inhibited the transactivity of PPARγ, but not PPAR α, β/δ and LXR α, β. TR-FRET assay revealed that PPT was specifically bound to PPARγ LBD, which was further confirmed by the molecular docking study. Our data demonstrate that PPT is a novel PPARγ antagonist. The inhibition of PPARγ activity could be a promising therapy for obesity and steatosis. Our findings shed new light on the mechanism of ginseng in the treatment of metabolic syndrome.

Topics: 3T3-L1 Cells; Adipocytes; Adipogenesis; Animals; Cell Differentiation; Diet, High-Fat; Disease Models, Animal; Electron Transport; Fatty Liver; Female; Gene Expression Regulation; Inflammation; Liver; Mice; Mitochondria; Obesity; Panax; PPAR gamma; Sapogenins