Project description:IBD is characterized by chronic recurrences of intestinal inflammation and intestinal immune disturbances.Bacteroides vulgatus can alleviate DSS-induced colitis in mice, but the mechanism is unknown. The aim of this study was to examine the changes in gene expression in the intestinal tissue of mice with colitis following treatment with Bacteroides vulgatus by RNA sequencing.
Project description:We previously found that mice deficient in the CD susceptibility gene Nod2 develop small intestinal abnormalities including impaired mucus production by goblet cells and susceptibility to injury, which were associated with interferon-gamma producing intraepithelial lymphocytes. These abnormalities were caused by a striking expansion of a common member of the microbiota, Bacteroides vulgatus. Remarkably, infection of Nod2-deficient mice with the helminth Trichuris muris led to a TH2 response that eliminated B. vulgatus colonization and intestinal abnormalities. In addition, treatment with recombinant IL13 (rIL13) or recombinant IL4 reduced B. vulgatus levels and eliminated goblet cell defects, suggesting that type 2 cytokines alone can reverse intestinal abnormalities in the absence of helminth infection. To determine the mechanism by which type 2 cytokines protected Nod2-/- mice from intestinal abnormalities, we performed RNA-seq on small intestinal tissue from WT, Nod2-/- and rIL13 treated Nod2-/- mice. We found that rIL13 treatment induced a wound healing response characterized by M2 macrophage activation genes. Hence, type 2 cytokines can reverse inflammatory imbalances in the composition of the gut microbiota that occurs in a genetically susceptible host.
Project description:Bacteroides, that expresses bile salt hydrolase (BSH), is considered as a potential drug target for metabolic diseases. In the present study, BSH-expressing Bacteroides was found to be enriched in two different CRC mouse models and colonization of nonenterotoxigenic Bacteroides species, such as B. fragilis 9343 or B. vulgatus , enhanced CRC growth. Expression of the 9343 bsh gene in B. fragilis 638R, a bsh - lacking strain, enabled more bile acids to escape into the colon and accelerated CRC progression . The presence of BSH activated WNT signaling and upregulated CCL28 expression dependent on b-catenin in colon tumors. The activated b-catenin/CCL28 axis elevated intra-tumororal immunosuppressive CD25+ FOXP3+ T reg cells. Anti-CCL28 antibody reversed microbial BSH amplificationinduced immunosuppression. Inhibition of BSH reduced CRC progression, coincident with suppression of WNT signaling and CCL28 expression. These findings provide a novel insight into the pro-carcinogenetic role of NTBF in CRC and characterize BSH as a potential target for CRC treatment.
Project description:Analysis of the gut transcriptome as affected by treatment with Bacteroides thetaiotaomicron in a mouse model of IBD Here, we report analysis of the gut transcriptome in IL10KO mice after treatment with Bacteroides thetaiotaomicron (BT). Comparative transcriptome analysis of ascending colon tissue of IL10KO and IL10KO/BT-treated mice showed differential expression of a wide range of genes associated with inflammatory responses between the two treatment groups. Expression of proinflammatory genes and genes involved in pathogen recognition was particularly lower in IL10KO/BT mice.