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
Project description:Dysbiosis of the gut microbiota has been linked to disease pathogenesis in type 1 diabetes (T1D), yet the functional consequences to the host of this dysbiosis is unknown. Here, we have performed a metaproteomic analysis of 103 stool samples from subjects that either had recent-onset T1D, were high-risk autoantibody positive or low-risk autoantibody negative relatives of individuals with beta cell autoimmunity or healthy individuals to identify signatures in host and microbial proteins associated with disease risk. Multivariate modelling analysis demonstrated that both human host proteins and microbial derived proteins could be used to differentiate new-onset and seropositive individuals from low-risk and healthy controls. Significant alterations were identified between subjects with T1D or islet autoimmunity versus autoantibody negative and control subjects in the prevalence of individual host proteins associated with exocrine pancreas function, inflammation and mucosal function. Data integrationIntegrative analysis combining the metaproteomic data with bacterial abundance showed that taxa that were depleted in new-onset T1D patients were positively associated with host proteins involved in maintaining function of the mucous barrier, microvilli adhesion and exocrine pancreas. These data support the notion that T1D patients have increased intestinal inflammation and decreased barrier function. They also confirmed that pancreatic exocrine dysfunction occurs in new-onset T1D patients and show for the first time that this dysfunction is present in high-risk individuals prior to disease onset. Our data has identified a unique T1D-associated signature in stool that may be useful as a means to monitor disease progression or response to therapies aimed at restoring a healthy microbiota.
Project description:We purified the intestinal epithelial cells from biopsies taken from the ileum and colon of a paediatric cohort of IBD patients and healthy controls
Project description:Aim: To compare the overall transcriptional profile in healthy controls and celiac disease patients. This dataset, was used to evaluate if our in vitro model (intestinal intraepithelial lymphocytes, desccribed in doi:10.1016/j.jaut.2020.10242 ) is representative of the transcriptional profile in the intestine under healthy or inflammatory conditions. Samples: Upper colonoscopy biopsies from 5 control and 11 celiac disease patients were taken, total RNA was extracted and RNA-sequencing was performed (without replicates)
Project description:The investigators hypothesize that an increase in dietary fiber intake during radiation therapy may provide better long-term intestinal health for the cancer survivor. If the hypothesis is not correct, the increased intake may only mean an increase in acute side effects. All participants are advised to consume at least 16 g of dietary fiber/day via food. In addition, participants are invited to take capsules that together contain either 5.5 g of dietary fiber from psyllium husk or placebo.
Project description:Application of a mass spectrometry -based approach to assess the gut microbiota composition and the associated metaproteomic functionality in patients with intestinal COVID-19 infection
Project description:Intestinal microbial dysbiosis is associated with Crohn’s disease (CD). However, the mechanisms leading to the chronic mucosal inflammation that characterizes this disease remain unclear. To evaluate causality and mechanisms of disease, we conducted a systems level study of the interactions between the gut microbiota and host in new-onset pediatric patients. We report an altered host proteome in CD patients indicative of impaired mitochondrial functions. A downregulation of mitochondrial proteins implicated in H2S detoxification was observed, while the relative abundance of H2S microbial producers was increased. Network correlation analysis identified Atopobium parvulum as the central hub of H2S producers. Gnotobiotic and conventionalized colitis-susceptible interleukin-10-deficient (Il10-/-) mice demonstrated that A. parvulum induced colitis, a phenotype requiring the presence of the intestinal microbiota. Administration of bismuth, a H2S scavenger, prevented A. parvulum-induced colitis in Il10-/- mice. This study identified host-microbiota interactions that are disturbed in CD patients providing mechanistic insights on CD pathogenesis.