Project description:Obesity is a chronic, complex and multifactorial disease that has reached pandemia levels and is becoming a serious health problem. Intestinal microbiota is considered a main factor that affects body weight and fat mass, which points toward a critical role in the development of obesity. In this sense, probiotic bacteria might modulate the intestinal microbiota and the mucosal-associated lymphoid tissue. The aim of this study was to investigate the effects of L. paracasei, L. rhamnosus and B. breve feeding on the intestinal mucosa gene expression in a genetic animal model of obesity. We used microarrays to investigate the global gene expression on intestinal mucosa after the treatment with probiotic strains.
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.
Project description:Group 3 innate lymphoid cells (ILC3s) are crucial for the maintenance of host-microbiota homeostasis in gastrointestinal mucosal tissues. The mechanisms that maintain lineage identity of intestinal ILC3s, and ILC3s-mediated orchestration of microbiota and mucosal T cell immunity are elusive. Here, we identified BATF as a gatekeeper of ILC3s homeostasis in the gut. Depletion of BATF in ILC3s resulted in excessive interferon-γ production, dysbiosis, aberrant T cell immune responses and spontaneous inflammatory bowel disease (IBD), which was considerably ameliorated by removal of adaptive immunity or antibiotic treatment. Mechanistically, BATF directly regulates ILC3s identity by globally shapes chromatin landscape of ILC3s. BATF directly binds to the cis-regulatory elements of type 1 effector genes, restrains their chromatin accessibility and inhibits their expression. Conversely, BATF promotes chromatin accessibility of genes involved in MHCII antigen processing and presentation pathways. Collectively, our findings reveal BATF is a promising candidate to maintain ILC3s stability and coordinate ILC3s–mediated control of intestinal homeostasis.
Project description:Group 3 innate lymphoid cells (ILC3s) are crucial for the maintenance of host-microbiota homeostasis in gastrointestinal mucosal tissues. The mechanisms that maintain lineage identity of intestinal ILC3s, and ILC3s-mediated orchestration of microbiota and mucosal T cell immunity are elusive. Here, we identified BATF as a gatekeeper of ILC3s homeostasis in the gut. Depletion of BATF in ILC3s resulted in excessive interferon-γ production, dysbiosis, aberrant T cell immune responses and spontaneous inflammatory bowel disease (IBD), which was considerably ameliorated by removal of adaptive immunity or antibiotic treatment. Mechanistically, BATF directly regulates ILC3s identity by globally shapes chromatin landscape of ILC3s. BATF directly binds to the cis-regulatory elements of type 1 effector genes, restrains their chromatin accessibility and inhibits their expression. Conversely, BATF promotes chromatin accessibility of genes involved in MHCII antigen processing and presentation pathways. Collectively, our findings reveal BATF is a promising candidate to maintain ILC3s stability and coordinate ILC3s–mediated control of intestinal homeostasis.
Project description:Pneumonia accounts for more deaths than any other infectious disease worldwide. The intestinal microbiota has emerged as a key defense system by local support of mucosal immunity as well as proposed modulatory effects on systemic immunity. We here investigated the transcriptomes of whole-lungs and alveolar macrophages between untreated and antibiotic treated mice.
Project description:Different regions of the gastrointestinal tract have distinct digestive and absorptive functions, which may be locally disrupted by infection or autoimmune disease. Yet, the mechanisms underlying intestinal regionalization and its dysregulation in disease are not well understood. Here, we used mouse models, transcriptomics, and immune profiling to show that regional epithelial expression of the transcription factor GATA4 prevented adherent bacterial colonization and inflammation in the proximal small intestine by regulating retinol metabolism and luminal IgA. Loss of epithelial GATA4 expression increased mortality in mice infected with Citrobacter rodentium which was dependent on commensal microbiota induced immunopathology. In active celiac patients with villous atrophy, low GATA4 expression was associated with metabolic alterations, mucosal Actinobacillus, and increased IL-17 immunity. This study reveals broad impacts of GATA4-regulated intestinal regionalization and highlights an elaborate interdependence of intestinal metabolism, immunity, and microbiota in homeostasis and disease.
Project description:Alterations in intestinal microbiota and intestinal short chain fatty acids profiles have been associated with the pathophysiology of obesity and insulin resistance. Whether intestinal microbiota dysbiosis is a causative factor in humans remains to be clarified We examined the effect of fecal microbial infusion from lean donors on the intestinal microbiota composition, glucose metabolism and small intestinal gene expression. Male subjects with metabolic syndrome underwent bowel lavage and were randomised to allogenic (from male lean donors with BMI<23 kg/m2, n=9) or autologous (reinfusion of own feces, n=9) fecal microbial transplant. Insulin sensitivity and fecal short chain fatty acid harvest were measured at baseline and 6 weeks after infusion. Intestinal microbiota composition was determined in fecal samples and jejunal mucosal biopsies were also analyzed for the host transcriptional response. Insulin sensitivity significantly improved six weeks after allogenic fecal microbial infusion (median Rd: from 26.2 to 45.3 μmol/kg.min, p<0.05). Allogenic fecal microbial infusion increased the overall amount of intestinal butyrate producing microbiota and enhanced fecal harvest of butyrate. Moreover, the transcriptome analysis of jejunal mucosal samples revealed an increased expression of genes involved in a G-protein receptor signalling cascade and subsequently in glucose homeostasis. Lean donor microbial infusion improves insulin sensitivity and levels of butyrate-producing and other intestinal microbiota in subjects with the metabolic syndrome. We propose a model wherein these bacteria provide an attractive therapeutic target for insulin resistance in humans. (Netherlands Trial Register NTR1776).
Project description:Nutrition has a vital role in shaping the intestinal microbiome. The impact of nutrients and the consequences of enteral deprivation on the small intestinal mucosal microbiota, specifically in early life, has not been well described. Our aim was to study the impact of enteral deprivation on the small intestine mucosal microbiome and to search for factors that shape this interaction in early life. Host seem to be the most dominant factor in the structure of the early life mucosal microbial small intestine community. Under conditions of nutrient deprivation, there are specific changes in host proteomics. Further research is needed to better define and understand this host-microbe-nutrition interaction in the small intestine.
Project description:Commensal microbiota contribute to gut homeostasis and influence mucosal gene expression. We harvested mucosal lining of middle and distal part of the small intestine and colon from germ-free (GF) and gnotobiotic mice monocolonized either with the E.coli strain O6K13 (O) or Nissle 1917 strain (N). The expression profiles of the mucosa samples were compared to the corresponding tissue isolated from conventionally reared mice in order to disclose genes differentially expressed in response to the change in the intestinal microflora composition.