Project description:Background: Humans with metabolic and inflammatory diseases frequently harbor lower levels of butyrate-producing bacteria in their gut. However, it is not known whether variation in the levels of these organisms is causally linked with disease development and whether diet modifies the impact of these bacteria on health. Results: We use germ-free apolipoprotein E-deficient mice colonized with synthetic microbial communities that differ in their capacity to generate butyrate to demonstrate that Roseburia intestinalis interacts with dietary components to (i) impact gene expression in the intestine, directing metabolism away from glycolysis and toward fatty acid utilization, (ii) improve intestinal barrier function, (iii) lower systemic inflammation and (iv) ameliorate atherosclerosis. Furthermore, intestinal administration of butyrate improves gut barrier function and reduces atherosclerosis development. Conclusions: Altogether, our results illustrate how modifiable diet-by-microbiota interactions impact cardiovascular disease, and suggest that interventions aimed at increasing the representation of butyrate-producing bacteria may provide protection against atherosclerosis.
Project description:Humans with metabolic and inflammatory diseases frequently harbour lower levels of butyrate-producing bacteria in their gut. However, it is not known whether variation in the levels of these organisms is causally linked with disease development and whether diet modifies the impact of these bacteria on health. Here we show that a prominent gut-associated butyrate-producing bacterial genus (Roseburia) is inversely correlated with atherosclerotic lesion development in a genetically diverse mouse population. We use germ-free apolipoprotein E-deficient mice colonized with synthetic microbial communities that differ in their capacity to generate butyrate to demonstrate that Roseburia intestinalis interacts with dietary plant polysaccharides to: impact gene expression in the intestine, directing metabolism away from glycolysis and toward fatty acid utilization; lower systemic inflammation; and ameliorate atherosclerosis. Furthermore, intestinal administration of butyrate reduces endotoxaemia and atherosclerosis development. Together, our results illustrate how modifiable diet-by-microbiota interactions impact cardiovascular disease, and suggest that interventions aimed at increasing the representation of butyrate-producing bacteria may provide protection against atherosclerosis.
Project description:Strain Roseburia intestinalis TSDC19.2-1.1 (species Roseburia intestinalis) was isolated from the fecal microbiota of a USA female at time point zero (bacterial isolates were sequenced from this donor on day 0 and 47). The species name was assigned by genome clustering.
Project description:?-Mannans are plant cell wall polysaccharides that are commonly found in human diets. However, a mechanistic understanding into the key populations that degrade this glycan is absent, especially for the dominant Firmicutes phylum. Here, we show that the prominent butyrate-producing Firmicute Roseburia intestinalis expresses two loci conferring metabolism of ?-mannans. We combine multi-"omic" analyses and detailed biochemical studies to comprehensively characterize loci-encoded proteins that are involved in ?-mannan capturing, importation, de-branching and degradation into monosaccharides. In mixed cultures, R. intestinalis shares the available ?-mannan with Bacteroides ovatus, demonstrating that the apparatus allows coexistence in a competitive environment. In murine experiments, ?-mannan selectively promotes beneficial gut bacteria, exemplified by increased R. intestinalis, and reduction of mucus-degraders. Our findings highlight that R. intestinalis is a primary degrader of this dietary fiber and that this metabolic capacity could be exploited to selectively promote key members of the healthy microbiota using ?-mannan-based therapeutic interventions.
Project description:Inflammatory bowel disease (IBD), which includes ulcerative colitis (UC) and Crohn's disease (CD), has a complex etiology that may be associated with dysbiosis of the microbiota. Previously, our study revealed significant loss of Roseburia intestinalis from the gut of untreated patients with CD, and that R. intestinalis exerted anti‑inflammatory functions in TNBS‑induced colitis; however, the function of R. intestinalis supernatant is unknown. Therefore, LPS‑induced macrophages, including RAW264.7 macrophages and bone marrow‑derived macrophages were treated with R. intestinalis supernatant. The results indicated that R. intestinalis supernatant suppressed expression of interleukin (IL)‑6 and signal transducer and activator of transcription 3 (STAT3) by macrophages. Additionally, these findings were further verified in vivo in DSS‑ and TNBS‑induced mouse models of colitis. It was observed that R. intestinalis supernatant ameliorated IBD colitis by reducing the number of inflammatory macrophages and Th17 cells in the colon, and by downregulating the expression of IL‑6 and STAT3. Finally, the non‑protein components of R. intestinalis supernatant were examined using gas chromatography‑mass spectrometry analysis and identified the presence of short‑chain fatty acids. In conclusion, the results of the present study indicated that R. intestinalis supernatant may regulate immune responses and ameliorate colitis.
Project description:β-Mannans are plant cell wall polysaccharides that are commonly found in human diets. However, a mechanistic understanding into the key populations that degrade this glycan is absent, especially for the dominant Firmicutes phylum. Here, we show that the prominent butyrate-producing Firmicute Roseburia intestinalis expresses two loci conferring metabolism of β-mannans. We combine multi-“omic” analyses and detailed biochemical studies to comprehensively characterize loci-encoded proteins that are involved in β-mannan capturing, importation, de-branching and degradation into monosaccharides. In mixed cultures, R. intestinalis shares the available β-mannan with Bacteroides ovatus, demonstrating that the apparatus allows coexistence in a competitive environment. In murine experiments, β-mannan selectively promotes beneficial gut bacteria, exemplified by increased R. intestinalis, and reduction of mucus-degraders. Our findings highlight that R. intestinalis is a primary degrader of this dietary fiber and that this metabolic capacity could be exploited to selectively promote key members of the healthy microbiota using β-mannan-based therapeutic interventions.
Project description:Roseburia intestinalis (R. intestinalis) is one of the dominant intestinal bacterial microbiota and is decreased in patients with inflammatory bowel disease (IBD). It helps protect colonic mucosa against the development of inflammation and subsequent IBD, however its underlying mechanisms are unclear. The aim of the present study was to evaluate the anti?inflammatory properties of R. intestinalis in vitro and in an animal model of IBD. The effects of R. intestinalis on disease activity index (DAI) scores, intestinal pathology, the expression of interleukin (IL)?17 and the frequency of CD4+CD25+Foxp3+ regulatory T cells (Treg) were evaluated in vivo in a model of 2,4,6?trinitrobenzenesulfonic acid solution (TNBS)?induced colitis. Compared with the control group, TNBS?treated mice had significantly higher secretion of IL?17, higher DAI scores, a lower ratio of Treg, reduced colon lengths and higher histological scores for colon inflammation. The administration of R. intestinalis significantly downregulated the expression of IL?17, increased the ratio of Treg and ameliorated the high DAI scores and the pathological signs of inflammation in the colon compared with mice treated with TNBS alone. Gene expression profiling was also used to detect the expression of IL?17 in human IBD and healthy control specimens. To extend these findings to an in vitro model of inflammation the human colon epithelial cell line NCM460 was stimulated with lipopolysaccharide (LPS) to induce inflammation and co?cultured with R. intestinalis and changes in IL?17 expression were evaluated. R. intestinalis inhibited the LPS?induced secretion of IL?17 by NCM460 cells. In conclusion, these results demonstrate that R. intestinalis inhibits IL?17 secretion and promotes Treg differentiation in colitis, suggesting that R. intestinalis could be of potential use in the treatment of IBD.