Project description:Neonatal mice were susceptible to cryptosporidium infection at 1- and 2-weeks of age, but were resistant to infection at 3- and 6-weeks of age. Diet and microbial changes are known to occur during the weaning transition in mice and we hypothesized that these changes in the intestinal luminal environment might influence resistance and susceptibility to cryptosporidium infection. As one part of testing this hypothesis, cecal microbiota composition was determined by 16S ribosomal RNA sequencing of DNA isolated from the cecal contents of mice at 1 week, 2 weeks, 3 weeks, and 6 weeks of age.
Project description:Using a systems biology approach, we discovered and dissected a three-way interaction between the immune system, the intestinal epithelium, and the microbiota. We found that mice lacking B lymphocytes, or lacking IgA, have low intestinal expression of lipid metabolism genes regulated by the transcription factor GATA4, and a consequent decrease in fat absorption in the intestine. The defect disappeared in germ free mice, suggesting that it is dependent on the microbiota; and sequencing analysis of the bacteria showed subtle differences between normal and B-cell deficient mice. Analysis of gene expression of gut biopsies from patients with common variable immunodeficiency and intestinal dysfunction revealed a high similarity to mouse B-cell knockout profiles. These data provide an explanation for a longstanding enigmatic association between immunodeficiency and defective lipid absorption in humans. this series represents the subsection of the study where we analize gene epxression in duodenum biopsies from CVID patients and contols with unrelated pathologies Reference sample is from normal duodenum (Clontech). Log2 ratio Cy5/Cy3 was used.
Project description:Eriocitrin, found in lemon fruit, has shown a wide range of biological properties. Herein, to evaluate the intestinal metabolic profile of eriocitrin in colon, the flavonoids in mice colon contents were identified by ultra performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UPLC-ESI-MS/MS), and a total of 136 flavonoids were found, including eriocitrin and its six metabolites (eriodictyol, homoeriodictyol, hesperetin, eriodictyol-3'-O-glucoside, hesperetin-7-O-glucoside and eriodictyol-7-O-(6''-O-galloyl) glucoside). Mice colon contents were used for 16S rDNA gene sequencing and gas chromatography-mass (GC-MS). Resultu showed that eriocitrin significantly alters the beta diversity of the gut microbiota, the probiotics such as Lachnospiraceae_UCG_006 were significantly enriched, and the production of butyrate, valerate and hexanoate in the colon pool of short-chain fatty acids (SCFAs) were significant increased. The spearman's association analysis performed some intestinal bacteria may be involved in the metabolism of eriocitrin. Collectively, our results preliminarily suggesting the metabolism of eriocitrin in the gut, demonstrate alterations of eriocitrin on gut microbiota, which warrants further investigation to determine its potential use in food and biomedical applications.
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:Using a systems biology approach, we discovered and dissected a three-way interaction between the immune system, the intestinal epithelium, and the microbiota. We found that mice lacking B lymphocytes, or lacking IgA, have low intestinal expression of lipid metabolism genes regulated by the transcription factor GATA4, and a consequent decrease in fat absorption in the intestine. The defect disappeared in germ free mice, suggesting that it is dependent on the microbiota; and sequencing analysis of the bacteria showed subtle differences between normal and B-cell deficient mice. Analysis of gene expression of gut biopsies from patients with common variable immunodeficiency and intestinal dysfunction revealed a high similarity to mouse B-cell knockout profiles. These data provide an explanation for a longstanding enigmatic association between immunodeficiency and defective lipid absorption in humans. This series represents first part of the study including: 1) B-cell KO mice of different strains and their controls 2) germ free B-cell Ko mice and their controls 3) B lymphocytes