Project description:Microbial dysbiosis has been identified in adult inflammatory bowel disease (IBD) patients. However, microbial composition and functional interplay between host genetics and microorganisms in early IBD onset remain poorly defined. Here, we identified and demonstrated the causal effect of Atopobium parvulum and the gut microbiota in pediatric IBD. Microbiota and proteomic profiling revealed that the abundance of A. parvulum, a potent H2S producer, was associated with increased disease severity and a concurrent reduction in the expression of the host H2S detoxification pathway. In the Il10-/- mouse model of inflammation, A. parvulum induced severe pancolitis that was dependent on the presence of the gut microbiota. In addition, we demonstrated that administration of bismuth, an H2S scavenger, prevented A. parvulum-induced colitis. Our findings identified Atopobium parvulum as a major mediator of inflammation severity, and revealed an alteration of the balance between the production and detoxification of H2S in the gastrointestinal tract.
Project description:The human intestinal microbiota plays an essential role in host health. Modifications in its composition and diversity could induce pathologies such as inflammatory bowel diseases (IBD). These diseases are characterized by an unbalanced intestinal microbiota (a process known as dysbiosis) and an altered immune response. Faecalibacterium prausnitzii, the most abundant commensal bacterium in the human intestinal microbiota of healthy individuals (representing more than 5% of the total bacterial population), has been reported to be lower in feces and mucosa-associated microbiota of IBD patients. In addition, we have shown that both F. prausnitzii and its culture supernatant (SN) have anti-inflammatory and protective effects in both acute and chronic colitis models. However, the host molecular mechanisms involved in these anti-inflammatory effects remain unknown. In order to address this issue, we performed DNA chip-based transcriptomic analyses in HT-29 human intestinal epithelial cells stimulated with TNF-a and exposed to F. prausnitzii SN or to BHI (growth medium for F prausnitzii).
Project description:Most of Colorectal cancer (CRC) diagnosed are candidates for surgical resection with curative intent, although colorectal surgery is associated with some complications that could be life-threatening. Antibiotic prophylaxis is commonly used prior to the admission for the prevention of postoperative complications. However, this intervention can change the composition of intestinal microbiota and promote adverse inflammatory outcomes in CRC patients after surgery.
It seems the combination of different fungal extracts could be beneficial because of their role in gut microbiota modulation and their anti-inflammatory activity. Therefore, the fungal extract nutraceutical MICODIGEST 2.0 could be used to reduced the complications after CRC surgery.
Based on this hypothesis, we have designed a double-bind randomized clinical trial to evaluate the effect of MICODIGEST 2.0 on the complications after surgery with curative intent for CRC.
Project description:Dysbiosis is linked to the pathogenesis of inflammatory bowel disease. Although there is a lot of interest in restoring the balance, we do not understand the effects of dysbiosis, especially on epithelial cells. In addition, we know that epithelial cells from IBD patients maintain intrinsic defects. For that reason, we aimed to unravel if epithelial cells of UC patients are more sensitive towards microbiota stimulation, compared to non-IBD controls. In addition, we analyzed the effect of UC microbiota or microbiota of healthy donors towards epithelial cells. Confluent organoid derived monolayers of 8 UC patients and 8 non-IBD controls were co-cultured for 6 hours with microbiota (3.10^8 cells) , derived of a healthy donor (HD) or UC patients. If applicable, epithelial cells were first cultured for 24 hours with an inflammatory mix (100 ng/mL TNFα, 20 ng/mL IL1β, 1 µg/mL Flagellin). The inflammatory stimulation was continued in the 6 hours co-culture.Transcriptomic expression of epithelial cells was evaluated after 6 hours co-culture by Truseq for Illumina.
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:<p>We investigate the hypothesis that consistent changes in the human gut microbiome are associated with Crohn's disease, a form of inflammatory bowel disease, and that altered microbiota contributes to pathogenesis. Analysis of this problem is greatly complicated by the fact that multiple factors influence the composition of the gut microbiota, including diet, host genotype, and disease state. For example, data from us and others document a drastic impact of diet on the composition of the gut microbiome. No amount of sequencing will yield a useful picture of the role of the microbiota in disease if samples are confounded with uncontrolled variables.</p> <p>We aim to characterize the composition of the gut microbiome while controlling for diet, host genotype, and disease state. Diet is controlled by analyzing children treated for Crohn's disease by placing them on a standardized elemental diet, and by testing effects of different diets on the gut microbiome composition in adult volunteers. Genotype is analyzed by large scale SNP genotyping, which is already underway and separately funded--team member Hakon Hakonarson is currently genotyping 50 children a week at ~half a million loci each and investigating connections with inflammatory bowel disease. Clinical status is ascertained in the very large IBD practice in the UPenn/CHOP hospital system. Effects of diet, host genotype, and disease state on the gut microbiome are summarized in a multivariate model, allowing connections between microbiome and disease to be assessed free of confounding factors.</p> <p>This project is divided into four sub-studies. In the Fecal Storage Methods (FSM) study, methods of stool storage and DNA extraction are compared to examine their impact on DNA sequence analysis results. The Controlled Feeding Experiment (CaFE) addresses the effects of controlled diets on the gut microbiome. In the Cross-sectional Study of Diet and Stool Microbiome Composition (COMBO), the effects of diet analyzed using surveys and deep sequencing of stool specimens. The fourth study, Pediatric Longitudinal Study of Elemental Diet and Stool Microbiome Composition (PLEASE), examines the effects of an elemental diet treatment on pediatric patients diagnosed with inflammatory bowel disease (IBD), particularly Crohn's disease.</p> <p> <ul> <li>Fecal Storage Methods (FSM): Cross-sectional study</li> <li>Controlled Feeding Experiment (CaFE): Controlled trial</li> <li>Cross-sectional Study of Diet and Stool Microbiome Composition (COMBO): Cross-sectional study</li> <li>Pediatric Longitudinal Study of Elemental Diet and Stool Microbiome Composition (PLEASE): Longitudinal cohort study</li> </ul> </p>
Project description:In the DSS-induced colitis model, the epithelial damage and resulting inflammation is restricted to the colon, with a potential influence on the microbial composition in the adjacent cecum. Several studies have reported changes of the gut microbiota in the DSS-induced colitis model and other mouse models of IBD. Furthermore, metaproteomics analysis of the gut microbiome in a mouse model of Crohn’s disease demonstrated that disease severity and location are microbiota-dependent, with clear evidence for the causal role of bacterial dysbiosis in the development of chronic ileal inflammation. We have developed a refined model of chronic DSS-induced colitis that reflects typical symptoms of human IBD without a risky body weight loss usually observed in DSS models [Hoffmann et al., submitted]. In this study, we used metaproteomics to characterize the disease-related changes in bacterial protein abundance and function in the refined model of DSS-induced colitis. To assess the structural and functional changes, we applied 16S rRNA gene sequencing and metaproteomics analysis of the intestinal microbiota in three different entities of the intestinal environment, i.e. colon mucus, colon content and cecum content.