Project description:Background and Aims: Many inflammatory diseases are associated with microbial dysbiosis, which may considerably alter the production of short-chain fatty acids (SCFAs). SCFAs are produced in the large bowel through bacterial fermentation of dietary fiber and play an important role in maintaining gut homeostasis. SCFAs, particularly acetate and butyrate, show beneficial immunomodulatory effects contributing to the prevention of inflammatory and allergic reactions. Thus, reduced production of SCFAs may impact on the mucosal immune responses critical to fighting pathogens. This study aims to determine the influence of SCFAs on a murine model of colonic bacterial infection. Methods: In the present study, we used acetate- (HAMSA) or butyrate- (HAMSB) yielding diets to deliver high concentrations of individual SCFAs to the large bowel of mice infected with C. rodentium. We assessed the effects of these SCFAs on clinical burden and gut pathogenicity in correlation with changes in bacteria growth, fecal microbiota composition, function and changes in the immunological profile. Results: Here we show in vitro that acetate and butyrate directly inhibited growth of the attaching and effacing (A/E) pathogen C. rodentium in a bacteriostatic manner. This correlated with reduced expression of Tir, a gene responsible for bacterial adherence and pathogenicity. Interestingly, HAMSA-fed mice presented reduced clinical scores during C. rodentium infection associated with high concentrations of fecal acetate. This was linked with compositional and functional changes in the microbiota when examining 16s sequencing and proteomics analysis. The HAMSA mediated is protection involved increased expression IL-22 and Muc-2 in the colon and increased numbers of CD8αα+ TCRγδ T cells in the colonic epithelium. These effects were dependent on GPR43, a metabolite-sensing GPCR that binds acetate. Conclusions: We established a promising new approach to moderate bacterial gut infections by manipulating the gut microbiota and mucosal immune tolerance through diets that yield the SCFA acetate.
Project description:Despite recent advances, severe acute pancreatitis (SAP) remains an extremely lethal inflammation with limited treatment options. Here, we provide compelling evidence of GV-971 (sodium oligomannate), an anti-Alzheimer's medication, as being a protective agent in various mouse SAP models. Microbiome sequencing, along with fecal microbiota transplantation and mass cytometry technology, unveiled that GV-971 reshapes the gut microbiota, increasing Faecalibacterium populations and modulating both peripheral and intestinal immune systems. A metabolomics analysis of cecal contents from GV-971–treated SAP mice further identified short-chain fatty acids, including propionate and butyrate, as key metabolites in inhibiting macrophage M1 polarization and subsequent lethal inflammation by blocking the MAPK pathway. These findings suggest GV-971 as a promising therapeutic for SAP by targeting the microbiota metabolic immune axis.
Project description:We analyzed gut microbiota composition in stool, inflammation factor and short chain fatty acid (SCFAs) in plasma, inflammatory and permeability marker in intestinal mucosa in inflammatory depression patients.
Project description:Obesity and overweight are closely related to diet, and gut microbiota play an important role in body weight and human health. The aim of this study was to explore how Lactobacillus curvatus HY7601 and Lactobacillus plantarum KY1032 supplementation alleviate obesity by modulating the human gut microbiome. A randomized, double-blind, placebo-controlled study was conducted on 72 overweight individuals. Over a 12-week period, probiotic groups consumed 5×10^9 colony-forming units of HY7601 and KY1032), whereas the placebo group consumed the same product without probiotics. After treatment, the probiotic group displayed a reduction in body weight (p <0.001), visceral fat mass (p <0.025), and waist circumference (p <0.007), and an increase in adiponectin (p <0.046), compared with the placebo group. Additionally, HY7601 and KY1032 supplementation modulated bacterial gut microbiota characteristics and beta diversity by increasing Bifidobacteriaceae and Akkermansiaceae, and decreasing Prevotellaceae and Selenomonadaceae. In summary, HY7601 and KY1032 probiotics exert anti-obesity effects by regulating the gut microbiota; hence, they have therapeutic potential for preventing or alleviating obesity and overweight.
2022-05-12 | GSE202489 | GEO
Project description:Cyclocarya paliurus leaves alleviate obesity via regulating gut microbiota
Project description:Germ-free mice are an indispensable tool in studying the gut microbiome and its effects on host physiology, though they are phenotypically different than their conventional counterparts. While antibiotic mediated microbiota depletion in conventional mice mimics the germ-free state, the scope of these reversible changes is unknown. We demonstrate robust hepatic transcriptomic alterations after antibiotic-mediated microbiota depletion together with depletion of luminal and portal vein levels of SCFAs though hepatic histone acetylation states remained largely unchanged.
Project description:Short-chain fatty acids (SCFAs) are the end-products of bacterial fermentation of dietary fibre, and can play a crucial role in regulating immunity and metabolism in the gut and peripheral tissues. Here we show that butyrrate, an SCFA, displayed antiviral effects in chicken respiratory epithelial cells, likely via the regulation of interferon-stimulated genes, particularly OASL. The observed antiviral signaling mechanism would involve HDAC inhibition and Sp1-dependent regulation of the OASL promoter, shedding light on new mechanisms through which the GM regulates poultry mucosal immunity along the gut-lung axis in the chicken.
Project description:Objective: To study the effects of Short Chain Fatty Acids (SCFAs) on arthritic bone remodeling. Methods: We treated a recently described preclinical murine model of psoriatic arthritis (PsA), R26STAT3Cstopfl/fl CD4Cre mice, with SCFA supplemented water. We also performed in vitro osteoclast differentiation assays in the presence of serum-level SCFAs to evaluate the direct impact of these microbial metabolites on maturation and function of osteoclasts. We further characterized the molecular mechanism of SCFAs by bulk transcriptomics analysis. Results: The osteoporosis condition in R26STAT3Cstopfl/fl CD4Cre animals is attributed primarily to an expansion of osteoclast progenitor cells (OCPs), leading to robust osteoclast differentiation. We show that SCFA supplementation can rescue the osteoporosis phenotype in this model of PsA. Our in vitro experiments revealed an inhibitory effect of the SCFAs on osteoclast differentiation, even at very low serum concentrations. This suppression of osteoclast differentiation enabled SCFAs to impede osteoporosis development in R26STAT3Cstopfl/fl CD4Cre mice. Further interrogation revealed that bone marrow derived OCPs from diseased mice expressed a higher level of SCFA receptors than that of control mice and that the progenitor cells in the bone marrow of SCFA-treated mice presented a modified transcriptomic landscape, suggesting a direct impact by SCFAs on osteoclast progenitors. Conclusion: We demonstrated how gut microbiota-derived SCFAs can regulate distal pathology, i.e., osteoporosis, and identified a potential therapeutic option for restoring bone density in rheumatic disease, further highlighting the critical role of the gut-bone axis in these disorders.
Project description:The gut microbiome is intricately coupled with immune regulation and metabolism, but its role in Coronavirus Disease 2019 (COVID-19) is not fully understood. Severe and fatal COVID-19 is characterized by poor anti-viral immunity and hypercoagulation, particularly in males. Here we define multiple pathways by which the gut microbiome protects mammalian hosts from SARS-CoV-2 intranasal infection, both locally and systemically, via production of short-chain fatty acids (SCFAs). SCFAs reduced viral burdens in the airways and intestines by downregulating the SARS-CoV-2 entry receptor, angiotensin-converting enzyme 2 (ACE2), and enhancing adaptive immunity in male animals. In order to identify other mechanisms by which SCFAs influence the outcome of SARS-CoV-2 infection, we performed RNA-seq on lungs from male GF mice given control or SCFA water for two weeks. We identified a novel role for the gut microbiome in regulating systemic coagulation response by limiting megakaryocyte proliferation and platelet turnover via the Sh2b3-Mpl axis. Taken together, our findings have unraveled novel functions of SCFAs and fiber-fermenting gut bacteria that might be leveraged as pan-coronavirus therapeutics to dampen viral entry and hypercoagulation and promote adaptive anti-viral immunity.
Project description:The human gut microbiota is a complex microbial community with critical functions for the host, including the transformation of various chemicals. While effects on microorganisms has been evaluated using single-species models, their functional effects within more complex microbial communities remain unclear. In this study, we investigated the response of a simplified human gut microbiota model (SIHUMIx) cultivated in an in vitro bioreactor system in combination with 96 deep-well plates after exposure to 90 different xenobiotics, comprising 54 plant protection products and 36 food additives and dyes, at environmentally relevant concentrations. We employed metaproteomics and metabolomics to evaluate changes in bacterial abundances, the production of Short Chain Fatty Acids (SCFAs), and the regulation of metabolic pathways. Our findings unveiled significant changes induced by 23 out of 54 plant protection products and 28 out of 36 food additives across all three categories assessed. Notable highlights include azoxystrobin, fluoroxypyr, and ethoxyquin causing a substantial reduction (log2FC <-0.5) in the concentrations of the primary SCFAs: acetate, butyrate, and propionate. Several food additives had significant effects on the relative abundances of bacterial species; for example, acid orange 7 and saccharin led to a 75% decrease in Clostridium butyricum, with saccharin causing an additional 2.5-fold increase in E. coli compared to the control. Furthermore, both groups exhibited up- and down-regulation of various pathways, including those related to the metabolism of amino acids such as histidine, valine, leucine, and isoleucine, as well as bacterial secretion systems and energy pathways like starch, sucrose, butanoate, and pyruvate metabolism. This research introduces an efficient in vitro technique that enables high-throughput screening of the structure and function of a simplified and well-defined human gut microbiota model against 90 chemicals using metaproteomics and metabolomics. We believe this approach will be instrumental in characterizing chemical-microbiota interactions especially important for regulatory chemical risk assessments.