Tartary buckwheat root polysaccharides ameliorate non-alcoholic fatty liver disease via the IL6-SOCS3-SREBP1c pathway

Polysaccharide from Panax japonicus C.A. Mey prevents non-alcoholic fatty liver disease development based on regulating liver metabolism and gut microbiota in mice

In this study, a new polysaccharide (PSPJ) with specific molecular weight and monosaccharide compositions was isolated and purified from the water extract of Panacis Japonici Rhizoma (PJR). 16S rRNA analysis and untargeted metabolomic analysis were used to assess PSPJ's efficacy in averting non-alcoholic fatty liver disease (NAFLD). This study indicated that PSPJ significantly reduced liver fat accumulation, the increase in blood lipids and ALT caused by HFD, indicating that PSPJ can prevent NAFLD. We demonstrated through cell experiments that PSPJ does not directly affect liver cells. The gut microbiota disorder and alterations in short-chain fatty acids (SCFAs) induced by the high-fat diet (HFD) were ameliorated by PSPJ, as evidenced by the analysis of 16S rRNA. In particular, supplementing PSPJ reduced the abundance of Turicibacter, Dubosiella, and Staphylococcus, and increased the abundance of Bacteroides, Blautia, and Lactobacillus. Untargeted metabolomic analysis shows that PSPJ improves liver metabolic disorders by regulating arachidonic acid metabolism, carbohydrate digestion and absorption, fatty acid biosynthesis, fatty acid metabolism and retinol metabolism. The findings of our investigation indicate that PSPJ has the potential to modulate liver metabolism through alterations in the composition of intestinal bacteria, hence preventing NAFLD.

Foxa2 attenuates steatosis and inhibits the NF-κB/IKK signaling pathway in nonalcoholic fatty liver disease

Objective

Forkhead box a2 (Foxa2) is proven to be an insulin-sensitive transcriptional regulator and affects hepatic steatosis. This study aims to investigate the mechanism by which Foxa2 affects nonalcoholic fatty liver disease (NAFLD).

Methods

Animal and cellular models of NAFLD were constructed using high-fat diet (HFD) feeding and oleic acid (OA) stimulation, respectively. NAFLD mice received tail vein injections of either an overexpressing negative control (oe-NC) or Foxa2 (oe-Foxa2) for four weeks. HepG2 cells were transfected with oe-NC and oe-Foxa2 for 48 h before OA stimulation. Histological changes and lipid accumulation were assessed using hematoxylin-eosin staining and oil red O staining, respectively. Expression of Foxa2, NF-κB/IKK pathway proteins, lipid synthesis proteins, and fatty acid β-oxidation protein in HFD mice and OA-induced HepG2 cells was detected using western blot.

Results

Foxa2 expression was downregulated in HFD mice and OA-induced HepG2 cells. Foxa2 overexpression attenuated lipid accumulation and liver injury, and reduced the levels of aspartate aminotransferase, alanine aminotransferase, total cholesterol, or triglyceride in HFD mice and OA-induced HepG2 cells. Moreover, Foxa2 overexpression decreased the expression of lipid synthesis proteins and increased fatty acid β-oxidation protein expression in the liver tissues. Furthermore, overexpression of Foxa2 downregulated the expression of p-NF-κB/NF-κB and p-IKK/IKK in OA-induced HepG2 cells. Additionally, lipopolysaccharide (NF-κB/IKK pathway activator) administration reversed the downregulation of lipid synthesis proteins and the upregulation of fatty acid β-oxidation protein.

Conclusion

Foxa2 expression is downregulated in NAFLD. Foxa2 ameliorated hepatic steatosis and inhibited the activation of the NF-κB/IKK signaling pathway.