Intestinal Microbiota Increases Cell Proliferation of Colonic Mucosa in Human-Flora-Associated (HFA) Mice.

Intestinal epithelium renewal strictly depends on fine regulation between cell proliferation, differentiation, and apoptosis. While murine intestinal microbiota has been shown to modify some epithelial cell kinetics parameters, less is known about the role of the human intestinal microbiota. Here, we investigated the rate of intestinal cell proliferation in C3H/HeN germ-free mice associated with human flora (HFA, n = 8), and in germ-free (n = 15) and holoxenic mice (n = 16).

Skews Human DC to Prime IL10-Producing T Cells Through TLR2/6/JNK Signaling and IL-10, IL-27, CD39, and IDO-1 Induction.

The human colonic mucosa contains regulatory type 1-like (Tr1-like, i.e., IL-10-secreting and Foxp3-negative) T cells specific for the gut , which are both decreased in Crohn's disease patients.

Impaired Aryl Hydrocarbon Receptor Ligand Production by the Gut Microbiota Is a Key Factor in Metabolic Syndrome.

The extent to which microbiota alterations define or influence the outcome of metabolic diseases is still unclear, but the byproducts of microbiota metabolism are known to have an important role in mediating the host-microbiota interaction. Here, we identify that in both pre-clinical and clinical settings, metabolic syndrome is associated with the reduced capacity of the microbiota to metabolize tryptophan into derivatives that are able to activate the aryl hydrocarbon receptor. This alteration is not merely an effect of the disease as supplementation with AhR agonist or a Lactobacillus strain, with a high AhR ligand-production capacity, leads to improvement of both dietary- and genetic-induced metabolic impairments, particularly glucose dysmetabolism and liver steatosis, through improvement of intestinal barrier function and secretion of the incretin hormone GLP-1.

Bilophila wadsworthia aggravates high fat diet induced metabolic dysfunctions in mice.

Dietary lipids favor the growth of the pathobiont Bilophila wadsworthia, but the relevance of this expansion in metabolic syndrome pathogenesis is poorly understood. Here, we showed that B. wadsworthia synergizes with high fat diet (HFD) to promote higher inflammation, intestinal barrier dysfunction and bile acid dysmetabolism, leading to higher glucose dysmetabolism and hepatic steatosis.

Expression of CCR6 and CXCR6 by Gut-Derived CD4/CD8α T-Regulatory Cells, Which Are Decreased in Blood Samples From Patients With Inflammatory Bowel Diseases.

Background & Aims: Faecalibacterium prausnitzii, a member of the Clostridium IV group of the Firmicutes phylum that is abundant in the intestinal microbiota, has anti-inflammatory effects. The relative level of F prausnitzii is decreased in fecal samples from patients with inflammatory bowel diseases (IBDs) compared with healthy individuals. Reduced F prausnitzii was correlated with relapse of Crohn's disease after surgery.

Card9 mediates susceptibility to intestinal pathogens through microbiota modulation and control of bacterial virulence.

Objective: In association with innate and adaptive immunity, the microbiota controls the colonisation resistance against intestinal pathogens. Caspase recruitment domain 9 (), a key innate immunity gene, is required to shape a normal gut microbiota. mice are more susceptible to the enteric mouse pathogen that mimics human infections with enteropathogenic and enterohaemorrhagic .

Functional Characterization of Novel Strains Isolated from Healthy Volunteers: A Step Forward in the Use of as a Next-Generation Probiotic.

is a major member of the Firmicutes phylum and one of the most abundant bacteria in the healthy human microbiota. depletion has been reported in several intestinal disorders, and more consistently in Crohn's disease (CD) patients. Despite its importance in human health, only few microbiological studies have been performed to isolate novel strains in order to better understand the biodiversity and physiological diversity of this beneficial commensal species.

CARD9 impacts colitis by altering gut microbiota metabolism of tryptophan into aryl hydrocarbon receptor ligands.

Complex interactions between the host and the gut microbiota govern intestinal homeostasis but remain poorly understood. Here we reveal a relationship between gut microbiota and caspase recruitment domain family member 9 (CARD9), a susceptibility gene for inflammatory bowel disease (IBD) that functions in the immune response against microorganisms. CARD9 promotes recovery from colitis by promoting interleukin (IL)-22 production, and Card9(-/-) mice are more susceptible to colitis.

Microorganisms linked to inflammatory bowel disease-associated dysbiosis differentially impact host physiology in gnotobiotic mice.

Studying host-microbiota interactions are fundamental to understanding the mechanisms involved in intestinal homeostasis and inflammation. In this work, we analyzed these interactions in mice that were mono-associated with six microorganisms that are representative of inflammatory bowel disease (IBD)-associated dysbiosis: the bacteria Bacteroides thetaiotaomicron, adhesive-invasive Escherichia coli (AIEC), Ruminococcus gnavus and Roseburia intestinalis; a yeast used as a probiotic drug, Saccharomyces boulardii CNCM I-745; and another yeast, Candida albicans. Extensive ex vivo analyses including colon transcriptomics, histology, immune response, bile acid metabolism and short-chain fatty acid production were studied.

Identification of metabolic signatures linked to anti-inflammatory effects of Faecalibacterium prausnitzii.

Unlabelled: Faecalibacterium prausnitzii is an anti-inflammatory commensal bacterium identified on the basis of human clinical data. The mechanisms underlying its beneficial effects are still unknown. Gnotobiotic mice harboring F.

Early colonizing Escherichia coli elicits remodeling of rat colonic epithelium shifting toward a new homeostatic state.

We investigated the effects of early colonizing bacteria on the colonic epithelium. We isolated dominant bacteria, Escherichia coli, Enterococcus faecalis, Lactobacillus intestinalis, Clostridium innocuum and a novel Fusobacterium spp., from the intestinal contents of conventional suckling rats and transferred them in different combinations into germfree (GF) adult rats.

CD4CD8αα lymphocytes, a novel human regulatory T cell subset induced by colonic bacteria and deficient in patients with inflammatory bowel disease.

How the microbiota affects health and disease is a crucial question. In mice, gut Clostridium bacteria are potent inducers of colonic interleukin (IL)-10-producing Foxp3 regulatory T cells (Treg), which play key roles in the prevention of colitis and in systemic immunity. In humans, although gut microbiota dysbiosis is associated with immune disorders, the underlying mechanism remains unknown.

Ecology and metabolism of the beneficial intestinal commensal bacterium Faecalibacterium prausnitzii.

Faecalibacterium prausnitzii is a major commensal bacterium, and its prevalence is often decreased in conditions of intestinal dysbiosis. The phylogenic identity of this bacterium was described only recently. It is still poorly characterized, and its specific growth requirements in the human gastrointestinal tract are not known.

Bacteroides thetaiotaomicron and Faecalibacterium prausnitzii influence the production of mucus glycans and the development of goblet cells in the colonic epithelium of a gnotobiotic model rodent.

Background: The intestinal mucus layer plays a key role in the maintenance of host-microbiota homeostasis. To document the crosstalk between the host and microbiota, we used gnotobiotic models to study the influence of two major commensal bacteria, Bacteroides thetaiotaomicron and Faecalibacterium prausnitzii, on this intestinal mucus layer. B.

Faecal D/L lactate ratio is a metabolic signature of microbiota imbalance in patients with short bowel syndrome.

Our objective was to understand the functional link between the composition of faecal microbiota and the clinical characteristics of adults with short bowel syndrome (SBS). Sixteen patients suffering from type II SBS were included in the study. They displayed a total oral intake of 2661±1005 Kcal/day with superior sugar absorption (83±12%) than protein (42±13%) or fat (39±26%).

Connecting dysbiosis, bile-acid dysmetabolism and gut inflammation in inflammatory bowel diseases.

Objective: Gut microbiota metabolises bile acids (BA). As dysbiosis has been reported in inflammatory bowel diseases (IBD), we aim to investigate the impact of IBD-associated dysbiosis on BA metabolism and its influence on the epithelial cell inflammation response.

Design: Faecal and serum BA rates, expressed as a proportion of total BA, were assessed by high-performance liquid chromatography tandem mass spectrometry in colonic IBD patients (42) and healthy subjects (29).

Microbiota matures colonic epithelium through a coordinated induction of cell cycle-related proteins in gnotobiotic rat.

Previous studies have suggested that intestinal microbiota modulates colonic epithelium renewal. The objective of our work was to study the effects of microbiota on colonic epithelium structure and cell cycle-related proteins by using gnotobiotic rats. Colonic crypts and amount of cell cycle-related proteins were compared between germ-free (GF), conventional (CV), and conventionalized rats by histochemistry and Western blot.

The key role of segmented filamentous bacteria in the coordinated maturation of gut helper T cell responses.

Microbiota-induced cytokine responses participate in gut homeostasis, but the cytokine balance at steady-state and the role of individual bacterial species in setting the balance remain elusive. Herein, systematic analysis of gnotobiotic mice indicated that colonization by a whole mouse microbiota orchestrated a broad spectrum of proinflammatory T helper 1 (Th1), Th17, and regulatory T cell responses whereas most tested complex microbiota and individual bacteria failed to efficiently stimulate intestinal T cell responses. This function appeared the prerogative of a restricted number of bacteria, the prototype of which is the segmented filamentous bacterium, a nonculturable Clostridia-related species, which could largely recapitulate the coordinated maturation of T cell responses induced by the whole mouse microbiota.

Comparative assessment of human and farm animal faecal microbiota using real-time quantitative PCR.

Pollution of the environment by human and animal faecal pollution affects the safety of shellfish, drinking water and recreational beaches. To pinpoint the origin of contaminations, it is essential to define the differences between human microbiota and that of farm animals. A strategy based on real-time quantitative PCR (qPCR) assays was therefore developed and applied to compare the composition of intestinal microbiota of these two groups.

Faecalibacterium prausnitzii is an anti-inflammatory commensal bacterium identified by gut microbiota analysis of Crohn disease patients.

A decrease in the abundance and biodiversity of intestinal bacteria within the dominant phylum Firmicutes has been observed repeatedly in Crohn disease (CD) patients. In this study, we determined the composition of the mucosa-associated microbiota of CD patients at the time of surgical resection and 6 months later using FISH analysis. We found that a reduction of a major member of Firmicutes, Faecalibacterium prausnitzii, is associated with a higher risk of postoperative recurrence of ileal CD.

Clostridium difficile and Clostridium perfringens species detected in infant faecal microbiota using 16S rRNA targeted probes.

Clostridium perfringens and Clostridium difficile are pathogenic clostridia potentially associated with gastrointestinal infections and allergy in infants. To enable the molecular detection and quantification of these species in the infant gut, two 16S rRNA oligonucleotide probes were developed: Cdif198 for C. difficile and Cperf191 for C.

Intestinal microflora and digestive toxicity of irinotecan in mice.

Purpose: Delayed diarrhea is the most important side effect of irinotecan. The aim of this study was to investigate the role of intestinal microflora on the induction of systemic and intestinal toxicity and diarrhea, studying germ-free and holoxenic mice i.p.