Project description:IL17B protected mice from dextran sodium sulfate (DSS)-induced colitis since IL17B deficiency resulted in severe DSS-induced colitis with exaggerated weight loss, shorter colon length, and elevated proinflammatory cytokine production in colon. For mechanism study, we use single cell transcriptional analyses of CD45+ immune cells in colonic lamina propria to detect the effect of IL-17B on colon LP immune cells in colitis. We found increased inflammatory macrophages infiltration in colon lamina propria after colitis induction expressing inflammatory cytokines such as S100a9, S100a8, Tnf, which was confirmed by real-time PCR and flow cytometry. Reconstitute of Il17b-/- mice with recombinant IL17B alleviated the severity of DSS-induced colitis. IL17B treatment also inhibited LPS-induced inflammation in bone marrow derived macrophage and in mice. These data indicate that IL17B exerting its inhibitory role in inflammation by regulating inflammatory macrophage response. In view of the protective effect of IL17B on DSS-induced colitis and LPS-induced inflammation, IL17B might represent a novel potential therapeutic approach to treat the inflammation.
Project description:IL17B protected mice from dextran sodium sulfate (DSS)-induced colitis since IL17B deficiency resulted in severe DSS-induced colitis with exaggerated weight loss, shorter colon length, and elevated proinflammatory cytokine production in colon. For mechanism study, we use single cell transcriptional analyses of CD45+ immune cells in colonic lamina propria to detect the effect of IL-17B on colon LP immune cells in colitis. We found increased inflammatory macrophages infiltration in colon lamina propria after colitis induction expressing inflammatory cytokines such as S100a9, S100a8, Tnf, which was confirmed by real-time PCR and flow cytometry. Reconstitute of Il17b-/- mice with recombinant IL17B alleviated the severity of DSS-induced colitis. IL17B treatment also inhibited LPS-induced inflammation in bone marrow derived macrophage and in mice. These data indicate that IL17B exerting its inhibitory role in inflammation by regulating inflammatory macrophage response. In view of the protective effect of IL17B on DSS-induced colitis and LPS-induced inflammation, IL17B might represent a novel potential therapeutic approach to treat the inflammation.
Project description:BACKGROUND: Appendicitis followed by appendectomy (AA) at a young age protects against later inflammatory bowel disease (IBD). Using a novel murine appendicitis model we earlier demonstrated that AA proffered significant protection against subsequent experimental colitis. AIM: To delineate genes and biological pathways involved in the protective effect of AA against subsequent colitis using gene set enrichment analysis (GSEA) of DNA microarray data. METHODS: Appendicitis and appendicectomy was done (5 week old male BALB/c mice) near the most proximal colon (caecal lymphoid follicles) and colonic samples were harvested from the most distal colon. Two consecutive laparotomies were done in control Sham-Sham (SS) mice. RNA was extracted (TRIzol®) from 4 individual colonic samples per group (AA group vs. SS group) with each sample taken independently through Affymetrix® microarray hybridization. For GSEA, data for more than 23,000 genes were exported from Partek and analyzed with GSEA software (with 2852 gene sets encoded) to establish correlates with phenotypes of the gene sets. RESULTS: Distal colonic expression of 636 gene-sets were significantly upregulated in AA group samples (False Discovery Rates (FDR) values < 1 % and p value < 0.001; stringent statistical selection). These were validated by quantitative PCR of 14 selected genes across the immunological spectrum and over time-intervals of 3 days, 14 days and 28 days. CONCLUSIONS: Many key immunological, apoptosis-related and cellular function-associated gene-sets involved in the protective effect of AA in experimental colitis were identified. Further analysis of these profiles and biological pathways will assist utilizing these gene products and manipulating various aspects of these pathways to develop better therapeutic strategies in the management of intractable IBD. Appendicitis and appendicectomy was done (5 week old male BALB/c mice) near the most proximal colon (caecal lymphoid follicles) and colonic samples were harvested from the most distal colon. Two consecutive laparotomies were done in control Sham-Sham (SS) mice. RNA was extracted (TRIzol®) from 4 individual colonic samples per group (AA group vs. SS group) with each sample taken independently through Affymetrix® microarray hybridization. variable_protocol: appendicitis and appendectomy: AA1, AA2, AA3, AA4 variable_protocol: sham/sham surgery: SS1, SS2, SS3, SS4 repeat_biological replicate: AA1, AA2, AA3, AA4 repeat_biological replicate: SS1, SS2, SS3, SS4 Upregulated gene-set linked as supplementary file.
Project description:BACKGROUND: Appendicitis followed by appendectomy (AA) at a young age protects against later inflammatory bowel disease (IBD). Using a novel murine appendicitis model we earlier demonstrated that AA proffered significant protection against subsequent experimental colitis. AIM: To delineate genes and biological pathways involved in the protective effect of AA against subsequent colitis using gene set enrichment analysis (GSEA) of DNA microarray data. METHODS: Appendicitis and appendicectomy was done (5 week old male BALB/c mice) near the most proximal colon (caecal lymphoid follicles) and colonic samples were harvested from the most distal colon. Two consecutive laparotomies were done in control Sham-Sham (SS) mice. RNA was extracted (TRIzol®) from 4 individual colonic samples per group (AA group vs. SS group) with each sample taken independently through Affymetrix® microarray hybridization. For GSEA, data for more than 23,000 genes were exported from Partek and analyzed with GSEA software (with 2852 gene sets encoded) to establish correlates with phenotypes of the gene sets. RESULTS: Distal colonic expression of 636 gene-sets were significantly upregulated in AA group samples (False Discovery Rates (FDR) values < 1 % and p value < 0.001; stringent statistical selection). These were validated by quantitative PCR of 14 selected genes across the immunological spectrum and over time-intervals of 3 days, 14 days and 28 days. CONCLUSIONS: Many key immunological, apoptosis-related and cellular function-associated gene-sets involved in the protective effect of AA in experimental colitis were identified. Further analysis of these profiles and biological pathways will assist utilizing these gene products and manipulating various aspects of these pathways to develop better therapeutic strategies in the management of intractable IBD.
Project description:Inflammatory bowel disease (IBD), comprising CrohnM-BM-4s disease and Ulcerative colitis, is characterized by chronic relapsing inflammation of the gut. It has been shown that increased proteasomal activity is associated with the expression of immunoproteasomes, which enhances NF-kB activation and thus promotes inflammation in IBD-patients. Here, we investigate whether modulation of the proteasomal activity is a suitable therapeutic approach to limit inflammation in colitis. This concept was tested in two different experimental setups. First, development of dextran sulfate sodium (DSS)-induced colitis was tested in lmp7-/--mice, which lack the essential immunoproteasome-subunit LMP7 or in wildtype-mice treated with the proteasome inhibitor bortezomib. Compared to WT mice, lmp7-/- mice revealed significantly attenuated colitis resulting from reduced NF-kB activation in the absence of LMP7. Further, treatment with bortezomib revealed dose-dependent amelioration of DSS-induced inflammation. In both approaches proteasome modulation limited the infiltration of neutrophils, consequently reducing tissue damage. In summary our experiments demonstrate that modulation of the proteasomal activity is effective in attenuating experimental colitis. In particular, our data suggest that the immunoproteasome-subunit LMP7 is a suitable target for the therapy of IBD. Microarray experiments were performed as dual-color hybridizations. To compensate for dye-specific effects, a dye-reversal color-swap was applied. Samples of proximal colon were cut longitudinally, washed in PBS, shortly incubated in 4M Guanidinium-isothiocyanat and transferred to TRIzol (Invitrogen).
Project description:Background & Aims: The complex interactions between diet and the microbiota that influence mucosal inflammation and inflammatory bowel disease are poorly understood. Experimental colitis models provide the opportunity to control and systematically perturb diet and the microbiota in parallel to quantify the contributions between multiple dietary ingredients and the microbiota on host physiology and colitis. Methods: To examine the interplay of diet and the gut microbiota on host health and colitis, we fed over 40 different diets with varied macronutrient sources and concentrations to specific pathogen free or germ free mice either in the context of healthy, unchallenged animals or dextran sodium sulfate colitis model. Results: Diet influenced physiology in both health and colitis across all models, with the concentration of protein and psyllium fiber having the most profound effects. Increasing dietary protein elevated gut microbial density and worsened DSS colitis severity. Depleting gut microbial density by using germ-free animals or antibiotics negated the effect of a high protein diet. Psyllium fiber influenced host physiology and attenuated colitis severity through microbiota-dependent and microbiota-independent mechanisms. Combinatorial perturbations to dietary protein and psyllium fiber in parallel explain most variation in gut microbial density, intestinal permeability, and DSS colitis severity, and changes in one ingredient can be offset by changes in the other. Conclusions: Our results demonstrate the importance of examining complex mixtures of nutrients to understand the role of diet in intestinal inflammation. Keywords: IBD; Diet; Microbiota; Mouse Models; Systems Biology