Project description:Study on the association between intestinal microbiota and enhanced inflammation observed in a particular group of colitis induced gankyrin deficient mice.
Project description:Abstract. Ulcerative colitis (UC) is an intestinal disease characterized by chronic recurrent inflammation, but the underlying mechanism remains undefined and requires in-depth exploration. The aim of the present study was to investigate the biological effects of a small molecular compound M1002 of oxygen-sensing signaling pathway on dextran sulfate sodium (DSS)-induced intestinal inflammation colitis mouse models. It was found that the protective effects of M1002 on DSS-induced colitis. To determine how M1002 exerted its protective effect in DSS-induced colitis, we compared the global gene expression profiles in the gut between DSS control and M1002 treatment colitis mouse groups by RNA-Seq. The results demonstrated that HIF-1 signaling pathway-related genes were significantly upregulated in the gut of M1002 treatment colitis mice, whereas the Inflammatory bowel disease signaling pathway, the TNF signaling pathway, and Cytokines and inflammatory response signaling pathway related genes were significantly downregulated in the M1002 treatment group. 16S rRNA gene sequencing demonstrated remarkable variations in the composition of gut microbiota between DSS control and M1002 treatment colitis mice. Compared with DSS control colitis mice, the relative abundance of Eubacterium_nodatum and Halomonas in the gut microbiota was significantly increased at genus level in the gut of M1002 treatment colitis mice. Based on these findings, we tend to conclude that M1002 might alleviate DSS-induced gut injury in mice by regulation of HIF-1 signaling and up-regulating Eubacterium_nodatum and Halomonas.
Project description:The gut and liver have been recognized to mutually communicate through the biliary tract, portal vein and systemic circulation, but it remains unclear how this gut-liver axis regulates intestinal physiology. Through hepatectomy, transcriptomics and proteomics profiling, we identified pigment epithelium-derived factor (PEDF), as a liver-derived soluble Wnt inhibitor, that can restrain intestinal stem cells (ISC) hyperproliferation for gut homeostasis by competing with Wnt ligands and suppressing Wnt/beta-catenin signaling pathway. In turn, microbial danger signals from intestinal inflammation can be sensed by the liver to repress PEDF production via peroxisome proliferator-activated receptor-alpha (PPAR alpha), liberating ISC proliferation to accelerate tissue repair in the gut. Further, treatment of mice with fenofibrate, a clinical agent of PPARalpha agonist for hypolipidemia enhances the susceptibility of colitis via PEDF activity. Therefore, we identified a distinct role of PEDF to calibrate ISC expansion for intestinal homeostasis via reciprocal interactions between the gut and liver.
Project description:Triclosan (TCS), an antimicrobial agent in thousands of consumer products, is a risk factor for colitis and colitis-associated colorectal cancer. While the intestinal toxicities of TCS require the presence of gut microbiota, the molecular mechanisms involved have not been defined. Here we show that intestinal commensal microbes mediate metabolic activation of TCS in the colon and drive its gut toxicology. Using a range of in vitro, ex vivo, and in vivo approaches, we identify specific microbial β-glucuronidase (GUS) enzymes involved and pinpoint molecular motifs required to metabolically activate TCS in the gut. Finally, we show that targeted inhibition of bacterial GUS enzymes abolishes the colitis-promoting effects of TCS, supporting the essential roles of specific microbial proteins in TCS toxicity. Our results define a mechanism by which intestinal microbes cause the gut toxicity of environmental chemicals and suggest a therapeutic approach to alleviate colitis and associated diseases.
Project description:Abstract. Background: The cause of ulcerative colitis (UC) is not yet fully understood. Previous research has pointed towards a potential role for mutations in NOD2 in promoting the onset and progression of inflammatory bowel disease (IBD) by altering the microbiota of the gut. However, the relationship between toll-like receptor 4 (TLR4) and gut microbiota in IBD is not well understood. To shed light on this, the interaction between TLR4 and gut microbiota was studied using a mouse model of IBD. Methods: To examine the function of TLR4 signaling in intestinal injury repair, researchers developed Dextran Sulfate Sodium Salt (DSS)-induced colitis and injury models in both wild-type (WT) mice and TLR4 knockout (TLR4-KO) mice. To assess changes in the gut microbiota, 16S rRNA sequencing was conducted on fecal samples from both the TLR4-KO and WT enteritis mouse models. Results: The data obtained depicted a protective function of TLR4 against DSS-induced colitis. The gut microbiota composition was found to vary considerably between the WT and TLR4-KO mice groups as indicated by β-diversity analysis and operational taxonomic units (OTUs) cluster. Statistical analysis of microbial multivariate variables depicted an elevated abundance of Escherichia coli/Shigella, Gammaproteobacteria, Tenerlcutes, Deferribacteres, Enterobacteria, Rikenellaceae, and Proteobacteria in the gut microbiota of TLR4-KO mice, whereas there was a considerable reduction in Bacteroidetes at five different levels of the phylogenetic hierarchy including phylum, class, order, family, and genus in comparison with the WT control. Conclusion: TLR4 may protect intestinal epithelial cells from damage in response to DSS-induced injury by controlling the microbiota in the gut.
Project description:Scutellarein ameliorates ulcerative colitis in mice via modulation of the intestinal barrier function, gut microbiota, and metabolites
Project description:Hepcidin is demonstrated to be the key iron regulatory hormone, produced by the liver. Here we show an unexpected role of hepcidin as a master initiator of the local and systemic inflammatory response. We found that hepcidin was highly expressed in the colon of two major idiopathic inflammatory bowel diseases : Crohn's disease (CD) and ulcerative colitis (UC). Thanks to the generation of intestinal specific hepcidin KO mice (Hepc{delta}int), we found in a DSS-induced colitis model that hepcidin mediated the induction of key inflammatory cytokines and was protective against intestinal injury. In a model of LPS-induced acute inflammation, intestinal hepcidin expression was increased through a TLR4 dependent pathway andwas required for intestinal neutrophil infiltration and inflammation. Strikingly, intestinal hepcidin was absolutely required for the systemic production of key inflammatory cytokines (IL-6, CXCL1, TNF-alpha ...) as well as for the setting of the hypoferremia of inflammation. In a sepsis model, Hepc{delta}int mice were protected against LPS-induced mortality. Mechanistically, we showed that hepcidin was a direct neutrophil chemoattractant and a proinflammatory molecule in macrophages through a Myd88 dependent pathway. Altogether, we demonstrated that Hepcidin is a key new essential component of the immune system and may be a promising target in many inflammatory diseases. We used microarrays to detail the global program of gene expression of BMDM treat with hepcidin for 1 hour.
Project description:The gut and liver are recognized to mutually communicate through the biliary tract, portal vein and systemic circulation, but it remains unclear how this gut-liver axis regulates intestinal physiology. Through hepatectomy, transcriptomic and proteomic profiling, we identified pigment epithelium-derived factor (PEDF), a liver-derived soluble Wnt inhibitor, that restrains intestinal stem cell (ISC) hyperproliferation to maintain gut homeostasis by suppressing the Wnt/b-catenin signaling pathway. Further, we found that microbial danger signals occurring as a result of intestinal inflammation can be sensed by the liver to repress PEDF production via peroxisome proliferator-activated receptor-a (PPARa), liberating ISC proliferation to accelerate tissue repair in the gut. Finally, treatment of mice with fenofibrate, a clinical agent of PPARa agonist for hypolipidemia enhances the susceptibility of colitis via PEDF activity. Therefore, we have identified a distinct role for PEDF in calibrating ISC expansion for intestinal homeostasis via reciprocal interactions between the gut and liver.