Project description:We profiled transcriptome and accessible chromatin landscapes in intestinal epithelial cells (IECs) from mice reared in the presence or absence of microbiota. We show that regional differences in gene transcription along the intestinal tract were accompanied by major alterations in chromatin organization. Surprisingly, we discovered that microbiota modify host gene transcription in IECs without significantly impacting the accessible chromatin landscape. Instead, microbiota regulation of host gene transcription might be achieved by differential expression of specific TFs and enrichment of their binding sites in nucleosome depleted CRRs near target genes. Our results suggest that the chromatin landscape in IECs is pre-programmed by the host in a region-specific manner to permit responses to microbiota through binding of open CRRs by specific TFs. mRNA and accessible chromatin (DNase-seq) profiles from colonic and ileal IECs were compared between conventionally-raised (CR), germ-free (GF), and conventionalized (CV) C57BL/6 mice.
Project description:Inappropriate cross talk between mammals and their gut microbiota may trigger intestinal inflammation and drive extra-intestinal immune-mediated diseases. Studies with germ-free or gnotobiotic animals represent the gold standard for research on bacterial-host interaction but they are not readily accessible to the wide scientific community. We aimed at refining a protocol that in a robust manner would deplete murine intestinal microbiota and prove to have significant biologic validity. Previously published protocols for depleting mice of their intestinal microbiota by administering broad-spectrum antibiotics in drinking water were difficult to reproduce. We show that twice daily delivery of antibiotics by gavage depleted mice of their cultivable fecal microbiota and reduced the fecal bacterial DNA load by approximately 400 fold while ensuring the animals’ health. Mice subjected to the protocol for 17 days displayed enlarged ceca, reduced Peyer’s patches and small spleens. Antibiotic treatment significantly reduced the expression of antimicrobial factors and altered the expression of 517 genes in total in the colonic epithelium. Genes involved in cell cycle were significantly altered concomitant with reduced epithelial proliferative activity in situ assessed by Ki-67 expression, suggesting that commensal microbiota drives cellular proliferation in colonic epithelium. We present a robust protocol for depleting mice of their cultivatable intestinal microbiota with antibiotics by gavage and show that the biological effect of this depletion is phenotypic characteristics and epithelial gene expression profile similar to those of germ-free mice. Comparison of genome-wide gene expression of colon intestinal epithelial cells from mice subjected to microbiota depletion protocol against to control mice.
Project description:We compare H3K9Ac enrichment in intestinal epithelial cells from intestine of germ-free and microbiota-replete (conventionally-housed) mice. Intestinal epithelial cells were harvested from the intestine of conventional or germ-free C57Bl6J mice. Chromatin immunoprecipitation was performed with anti-H3K9Ac. Sequencing was performed using the Illumina HiSeq2500. Reads were mapped to the mm10 genome using Bowtie. Microbiota induce loss of H3K9Ac within mulitple sites of the Clec2e gene.
Project description:We reported the effects of AOS10 on the intestinal microbiota, and found that this drug could benefit the pig's sperm quantity via improvement of intestinal microbiota.
Project description:The intestinal microbiota is a key regulator of mammalian lipid absorption, metabolism, and storage. Here we show that the microbiota reprograms intestinal lipid metabolism in mice by repressing the expression of long non-coding RNA (lncRNA) Snhg9 in small intestinal epithelial cells. Snhg9 suppressed the activity of the transcription factor peroxisome proliferator–activated receptor γ (PPARγ) – a central regulator of lipid metabolism – by dissociating the PPARγ inhibitor Sirtuin 1 from cell cycle and apoptosis protein 2 (CCAR2). Forced expression of Snhg9 in the intestinal epithelium of conventional mice lowered dietary lipid absorption, reduced body fat, and protected against diet-induced obesity. The microbiota repressed Snhg9 expression through an immune cell signaling relay encompassing myeloid cells and innate lymphoid cells. Our findings thus identify an unanticipated role for a lncRNA in microbial control of host metabolism.
Project description:The intestinal microbiota has been identified as an environmental factor that markedly impacts energy storage and body fat accumulation, yet the underlying mechanisms remain unclear. Here we show that the microbiota regulates body composition through the circadian transcription factor NFIL3. Nfil3 transcription oscillates diurnally in intestinal epithelial cells and the amplitude of the circadian oscillation is controlled by the microbiota through type 3 innate lymphoid cells (ILC3), STAT3, and the epithelial cell circadian clock. NFIL3 controls expression of a circadian lipid metabolic program and regulates lipid absorption and export in intestinal epithelial cells. These findings provide mechanistic insight into how the intestinal microbiota regulates body composition and establish NFIL3 as an essential molecular link among the microbiota, the circadian clock, and host metabolism.
Project description:Objective: Roux-Y gastric bypass (RYGB) surgery is a last treatment resort to induce substantial and sustained weight loss in severe obesity. The anatomical rearrangement affects the intestinal microbiota but so far, little information is available how it interferes with microbial functionality and microbial-host interaction independent from weight loss. Design: A RYGB rat model was utilized and compared to sham-operated controls which were kept at matched body weight as RYGB animals by food restriction. We assessed microbial taxonomy by 16S rRNA gene sequencing and functional activity by metaproteomics and metabolomics on microbiota samples collected separately from the ileum, the cecum as well as the colon and separately analysed the lumen and mucus associated microbiota. Results: Altered gut architecture in RYGB strongly affected the occurrence of Actinobacteria, especially Bifidobacteriaceae and Proteobacteria which were increased, whereas Firmicutes were decreased, although Streptococcaceae and Clostridium perfringens were observed at higher abundances. A decrease of conjugated as well as secondary bile acids was observed in the RYGB-gut lumen. In addition the arginine biosynthesis pathway in the microbiota was altered, indicated by the changes in abundance of upstream metabolites and enzymes, resulting in lower levels of arginine and higher levels of aspartate in the colon after RYGB. Conclusion: The anatomical rearrangement in RYGB affects microbiota composition and functionality by changes in amino acid and bile acid metabolism, independent of weight loss. The shift in microbiota taxonomic structure after RYGB may be mediated by the resulting change in composition of the bile acid pool in the gut lumen.
Project description:Although much research has been done on the diversity of gut microbiome, little is known about the way it influences intestinal homeostasis under normal and pathogenic conditions. Epigenetic mechanisms have recently been suggested as operating at the interface between the microbiota and the intestinal epithelium cells (IECs). Using genome-wide analyses, we discovered that exposure to microbiota induced both global DNA hypomethylation and localized changes at regulatory elements, which culminates in activation of a set of “early sentinel” response genes that play a role in maintaining gut homeostasis. Furthermore, we demonstrated that exposure to microbiota in acute inflammation results in profound DNA methylation and chromatin accessibility changes at regulatory elements leading to alterations in the gene expression program in colitis and colon cancer. Our studies add a new dimension to our understanding of the cross talk between the microbiota and IECs, and provide the foundation for how microbiota impact epigenetic programming.