Untargeted metabolomics reveals the role of AQP9 in nonalcoholic fatty liver disease in a mice model

Optimization of enzyme-assisted microwave extraction, structural characterization, antioxidant activity and in vitro protective effect against H2O2-induced damage in HepG2 cells of polysaccharides from roots of Rubus crataegifolius Bunge

In this study, an enzyme-assisted microwave extraction process was obtained by response surface method of polysaccharide from roots of Rubus crataegifolius Bunge. The optimized extraction process was as follow: enzyme dosage 2 %, enzymatic time was 3.6 h, enzymatic pH 4.9, and microwave time 4.7 min, with the extraction yield of 9.07 %. Four homogeneous polysaccharides (RCP-1, RCP-3, RCP-4 and RCP-5) were purified through column chromatography. Four polysaccharides have the relative higher molecular weights of 1.70 × 106 Da, 5.56 × 106 Da, 4.97 × 106 Da, and 9.80 × 106 Da and mainly consisted of GluN, GluA, Glu, Gal and Arab. FT-IR and NMR spectral analysis confirmed that the purified polysaccharides were polypyranose containing α- and β-glycosidic bonds. RCP - 1 has a relative high crystallinity. Four purified polysaccharides contained triple helical conformations, and have good antioxidant activities. Among the purified polysaccharides, RCP - 1 was found to reduce the oxidative cell damage induced by H2O2 through increasing of cell viability, inhibition of AST and ALT levels, ROS production and cell apoptosis, increasing of the activities of antioxidative enzymes, as well as reduction of MDA content. Our findings would provide a foundation for purified polysaccharides efficient extraction and demonstrated that the polysaccharides from R. crataegifolius roots could be a promising hepatoprotective agent.

Effects of short-term carbohydrate deprivation on glycolipid metabolism and hepatic lipid accumulation in mice

To investigate the effect of dietary carbohydrate levels on liver glycolipid metabolism, this study used C57BL/6J male mice receiving standard diet (CON), no-carbohydrate high-fat diet (NCD), and high-carbohydrate no-fat diet (HCD). One week after intervention, mice in the NCD group showed lower blood glucose, HbA1c and LDL-C as well as liver weight and liver index compared with the CON group. Further research found that the liver fat synthesis genes of mice in the NCD group were significantly down-regulated at the gene level, and histopathological sections showed that the livers of mice in the NCD group had less lipid accumulation. Furthermore, liver metabolomic analysis showed that primary bile acid levels and acylcarnitine levels in the liver of mice in the NCD group were significantly increased, and conversely, lysophosphatidylcholine and fatty acyl metabolites were significantly decreased. KEGG metabolic pathway analysis showed that metabolic pathways such as biosynthesis of unsaturated fatty acids and starch and sucrose metabolism were significantly inhibited in mice in the NCD group, while metabolic pathways such as primary bile acid biosynthesis, linoleic acid metabolism and glycerophospholipid metabolism were enhanced. Taken together, these results indicate that short-term carbohydrate deprivation improves blood glucose and lipid metabolism levels in mice; the molecular mechanism of action may involve inhibition of de novo lipogenesis and enhancement of bile acid metabolism.

A Novel Dry-Cured Ham Broth-Derived Peptide JHBp2 Effectively Inhibits Salmonella typhimurium In Vitro: Integrated Metabolomic, Proteomic, and Molecular Simulation Analyses

JHBp2 is a peptide purified from Jinhua ham broth with antibacterial activity against Salmonella typhimurium. Untargeted metabolomics and label-free quantitative proteomics were used to analyze metabolic and protein expression changes in S. typhimurium after JHBp2 treatment. Cell wall and membrane damage results indicate that JHBp2 has membrane-disruptive properties, causing leakage of intracellular nucleic acids and proteins. Metabolomics revealed 516 differentially expressed metabolites, involving cofactor biosynthesis, purine metabolism, ABC transporters, glutathione metabolism, pyrimidine metabolism, etc. Proteomics detected 735 differentially expressed proteins, involving pyruvate metabolism, amino acid biosynthesis, purine metabolism, carbon metabolism, glycolysis/gluconeogenesis, etc. RT-qPCR and proteomics results showed a positive correlation, and molecular docking demonstrated stable binding of JHBp2 to some differentially expressed proteins. In summary, JHBp2 could disrupt the S. typhimurium cell wall and membrane structure, interfere with synthesis of membrane-related proteins, trigger intracellular substance leak, and reduce levels of enzymes and metabolites involved in energy metabolism, amino acid anabolism, and nucleotide anabolism.

Untargeted metabonomics and TLR4/ NF-κB signaling pathway analysis reveals potential mechanism of action of Dendrobium huoshanense polysaccharide in nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is marked by hepatic steatosis accompanied by an inflammatory response. At present, there are no approved therapeutic agents for NAFLD. Dendrobium Huoshanense polysaccharide (DHP), an active ingredient extracted from the stems of Dendrobium Huoshanense, and exerts a protective effect against liver injury. However, the therapeutic effects and mechanisms of action DHP against NAFLD remain unclear. DHP was extracted, characterized, and administered to mice in which NAFLD had been induced with a high-fat and high-fructose drinking (HFHF) diet. Our results showed that DHP used in this research exhibits the characteristic polysaccharide peak with a molecular weight of 179.935 kDa and is composed primarily of Man and Glc in a molar ratio of 68.97:31.03. DHP treatment greatly ameliorated NAFLD by significantly reducing lipid accumulation and the levels of liver function markers in HFHF-induced NAFLD mice, as evidenced by decreased serum levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), total cholesterol (TC) and total triglyceride (TG). Furthermore, DHP administration reduced hepatic steatosis, as shown by H&E and Oil red O staining. DHP also inhibited the Toll-like receptor 4 (TLR4)/nuclear factor-kappa B (NF-κB) signaling pathway expression, thereby reducing levels of hepatic proinflammatory cytokines. Besides, untargeted metabolomics further indicated that 49 metabolites were affected by DHP. These metabolites are strongly associated the metabolism of glycine, serine, threonine, nicotinate and nicotinamide, and arachidonic acid. In conclusion, DHP has a therapeutic effect against NAFLD, whose underlying mechanism may involve the modulation of TLR4/NF-κB, reduction of inflammation, and regulation of the metabolism of glycine, serine, threonine, nicotinate and nicotinamide metabolism, and arachidonic acid metabolism.

Roles of immune dysregulation in MASLD

Metabolic dysfunction-associated steatotic liver disease (MASLD) is the most common chronic liver disease worldwide. Its occurrence and progression involve the process from simple hepatic steatosis to metabolic dysfunction associated steatohepatitis (MASH), which could develop into advanced liver fibrosis, cirrhosis, or hepatocellular carcinoma (HCC). Growing evidences support that the pathogenesis and progression of MASLD are closely related to immune system dysfunction. This review aims to summarize the association of MASLD with immune disorders and the prospect of using immunotherapy for MASLD.

Sigma-1 receptor knockout disturbs gut microbiota, remodels serum metabolome, and exacerbates isoprenaline-induced heart failure

Introduction

Heart failure (HF) is usually the end stage of the continuum of various cardiovascular diseases. However, the mechanism underlying the progression and development of HF remains poorly understood. The sigma-1 receptor (Sigmar1) is a non-opioid transmembrane receptor implicated in many diseases, including HF. However, the role of Sigmar1 in HF has not been fully elucidated.

Methods

In this study, we used isoproterenol (ISO) to induce HF in wild-type (WT) and Sigmar1 knockout (Sigmar1-/-) mice. Multi-omic analysis, including microbiomics, metabolomics and transcriptomics, was employed to comprehensively evaluate the role of Sigmar1 in HF.

Results

Compared with the WT-ISO group, Sigmar1-/- aggravated ISO-induced HF, including left ventricular systolic dysfunction and ventricular remodeling. Moreover, Sigmar1-/- exacerbated ISO-induced gut microbiota dysbiosis, which was demonstrated by the lower abundance of probiotics g_Akkermansia and g_norank_f_Muribaculaceae, and higher abundance of pathogenic g_norank_f_Oscillospiraceae and Allobaculum. Furthermore, differential metabolites among WT-Control, WT-ISO and Sigmar-/--ISO groups were mainly enriched in bile secretion, tryptophan metabolism and phenylalanine metabolism, which presented a close association with microbial dysbiosis. Corresponding with the exacerbation of the microbiome, the inflammation-related NOD-like receptor signaling pathway, NF-kappa B signaling pathway and TNF signaling pathway were activated in the heart tissues.

Conclusion

Taken together, this study provides evidence that a Sigmar1 knockout disturbs the gut microbiota and remodels the serum metabolome, which may exacerbate HF by stimulating heart inflammation.

Physiological and Metabolic Changes in Tamarillo (Solanum betaceum) during Fruit Ripening

Physiological and metabolic profiles in tamarillo were investigated to reveal the molecular changes during fruit maturation. The firmness, ethylene production, soluble sugar contents, and metabolomic analysis were determined in tamarillo fruit at different maturity stages. The firmness of tamarillo fruit gradually decreased during fruit ripening with increasing fructose and glucose accumulation. The rapid increase in ethylene production was found in mature fruit. Based on the untargeted metabolomic analysis, we found that amino acids, phospholipids, monosaccharides, and vitamin-related metabolites were identified as being changed during ripening. The contents of malic acid and citric acid were significantly decreased in mature fruits. Metabolites involved in phenylpropanoid biosynthesis, phenylalanine metabolism, caffeine metabolism, monoterpenoid biosynthesis, and thiamine metabolism pathways showed high abundance in mature fruits. However, we also found that most of the mature-enhanced metabolites showed reduced abundance in over-mature fruits. These results reveal the molecular profiles during tamarillo fruit maturing and suggest tamarillos have potential benefits with high nutrition and health function.