Project description:We compared the microbiota of paired mouse caecal contents and faeces by applying a multi-omic approach, including 16S rDNA sequencing, shotgun metagenomics, and shotgun metaproteomics. The aim of the study was to verify whether faecal samples are a reliable proxy for the mouse colonic luminal microbiota, as well as to identify changes in taxonomy and functional activity between caecal and faecal microbial communities, which have to be carefully considered when using stool as sample for mouse gut microbiota investigations.
2017-03-31 | PXD004911 | Pride
Project description:Microbiota of rat colonic chyme
Project description:Colorectal cancer risk is associated with diets high in red meat. Heme, the pigment of red meat, induces cytotoxicity of colonic contents and elicits epithelial damage and compensatory hyperproliferation, leading to hyperplasia. Here we explore the possible causal role of the gut microbiota in heme-induced hyperproliferation. To this end, mice were fed a purified control or heme diet (0.5 μmol/g heme) with or without broad-spectrum antibiotics for 14 d. Heme-induced hyperproliferation was shown to depend on the presence of the gut microbiota, because hyperproliferation was completely eliminated by antibiotics, although heme-induced luminal cytotoxicity was sustained in these mice. Colon mucosa transcriptomics revealed that antibiotics block heme-induced differential expression of oncogenes, tumor suppressors, and cell turnover genes, implying that antibiotic treatment prevented the heme-dependent cytotoxic micelles to reach the epithelium. Our results indicate that this occurs because antibiotics reinforce the mucus barrier by eliminating sulfide-producing bacteria and mucin-degrading bacteria (e.g., Akkermansia). Sulfide potently reduces disulfide bonds and can drive mucin denaturation and microbial access to the mucus layer. This reduction results in formation of trisulfides that can be detected in vitro and in vivo. Therefore, trisulfides can serve as a novel marker of colonic mucolysis and thus as a proxy for mucus barrier reduction. In feces, antibiotics drastically decreased trisulfides but increased mucin polymers that can be lysed by sulfide. We conclude that the gut microbiota is required for heme-induced epithelial hyperproliferation and hyperplasia because of the capacity to reduce mucus barrier function. Mice were fed a Westernized high fat control diet, or the same diet supplemented with 0.5 µmol heme/g diet. One group of control and one group of heme mice received a mixture of broad spectrum Antibiotics (Abx) (ampicilin, neomycin and metronidazole) in their drinking water. After 14 days of intervention, mice were killed and gene expression was profiled in colon.
Project description:The colon contains a dense metabolically potent microbiota. The colonic O-glycan-rich mucus has been recognized as a key barrier to prevent microbial intrusion, but how this system forms and functions remains unclear. Here, we discovered that the colon mucus is mainly forged by microbiota-dependent secretion of O-glycosylated Muc2 by goblet cells in the ascending colon, where it seamlessly encapsulates the fecal materials including the microbiota. Deletion of O-glycans in the ascending colon impaired the segregating function of the mucous coating, leading to altered structure and metabolic output of the microbiota, and transcriptional homeostasis of the entire host mucosa. These findings represent a paradigm change of the prevailing model of the colon mucus system and provides new insights into host and microbiota symbiosis.
Project description:The colon contains a dense metabolically potent microbiota. The colonic O-glycan-rich mucus has been recognized as a key barrier to prevent microbial intrusion, but how this system forms and functions remains unclear. Here, we discovered that the colon mucus is mainly forged by microbiota-dependent secretion of O-glycosylated Muc2 by goblet cells in the ascending colon, where it seamlessly encapsulates the fecal materials including the microbiota. Deletion of O-glycans in the ascending colon impaired the segregating function of the mucous coating, leading to altered structure and metabolic output of the microbiota, and transcriptional homeostasis of the entire host mucosa. These findings represent a paradigm change of the prevailing model of the colon mucus system and provides new insights into host and microbiota symbiosis.
Project description:To increase our knowledge of the effects of Fructo oligosaccharides (FOS) on Salmonella infection in fats, a controlle rat infection study was performed. Two groups of 12 rats were adapted for 14 days to a cellulose diet and one group of 12 rats to a FOS diet. One cellulose-fed group and the FOS-fed group were infected with Salmonella. Two days post infection mRNA was collected from the mucosa of the colon and changes in gene expression were assessed using an Agilent rat whole genome microarray (G4131A Agilent Technologies). Results indicate that Salmonella affects colonic mucosal gene expression, which is further enhanded by dietary FOS. Keywords: Dietary infection study, colon mucosa, Rat
2007-10-18 | GSE7472 | GEO
Project description:Colonic mucosa-associated gut microbiota by 16S sequencing
Project description:Colorectal cancer risk is associated with diets high in red meat. Heme, the pigment of red meat, induces cytotoxicity of colonic contents and elicits epithelial damage and compensatory hyperproliferation, leading to hyperplasia. Here we explore the possible causal role of the gut microbiota in heme-induced hyperproliferation. To this end, mice were fed a purified control or heme diet (0.5 μmol/g heme) with or without broad-spectrum antibiotics for 14 d. Heme-induced hyperproliferation was shown to depend on the presence of the gut microbiota, because hyperproliferation was completely eliminated by antibiotics, although heme-induced luminal cytotoxicity was sustained in these mice. Colon mucosa transcriptomics revealed that antibiotics block heme-induced differential expression of oncogenes, tumor suppressors, and cell turnover genes, implying that antibiotic treatment prevented the heme-dependent cytotoxic micelles to reach the epithelium. Our results indicate that this occurs because antibiotics reinforce the mucus barrier by eliminating sulfide-producing bacteria and mucin-degrading bacteria (e.g., Akkermansia). Sulfide potently reduces disulfide bonds and can drive mucin denaturation and microbial access to the mucus layer. This reduction results in formation of trisulfides that can be detected in vitro and in vivo. Therefore, trisulfides can serve as a novel marker of colonic mucolysis and thus as a proxy for mucus barrier reduction. In feces, antibiotics drastically decreased trisulfides but increased mucin polymers that can be lysed by sulfide. We conclude that the gut microbiota is required for heme-induced epithelial hyperproliferation and hyperplasia because of the capacity to reduce mucus barrier function.
Project description:Salmonella enteritidis is suggested to translocate in the small intestine. Previously we identified that prebiotics, fermented in the colon, increased Salmonella translocation in rats, suggesting involvement of the colon in translocation. Effects of Salmonella on colonic gene expression in vivo are largely unknown. The aim of this study was to characterize time dependent Salmonella induced changes of colonic mucosal gene expression in rats using whole genome microarrays. Rats were orally infected with Salmonella enteritidis to mimic a foodbore infection and colonic gene expression was determined at day 1, 3 and 6 post-infection (n=8 per timepoint). Agilent rat whole genome microarray (G4131A Agilent Technologies) were used. Results indicate that colon is clearly a target tissue for Salmonella considering the abundant changes in mucosal gene expression observed. Keywords: Time point infection study, colon mucosa, Rat