Project description:Recent advances in (meta)genomic methods have provided new opportunities to examine host-microbe-environment interactions in the human gut. While opportunities exist to extract DNA from freshly sourced colonic tissue there are potentially valuable sources of DNA from historical studies that might also be examined. We examined how four different tissue DNA extraction methods employed in past clinical trials might impact the recovery of microbial DNA from a colonic tissue sample as assessed using a custom designed phylogenetic microarray for human gut bacteria and archaebacteria. While all methods of DNA extraction produced similar phylogenetic profiles some extraction specific biases were also observed. Real time PCR analysis targeting several bacterial groups substantiated this observation. These data suggest that while the efficacy of different DNA extraction methods differs somewhat all the methods tested produce an accurate representation of microbial diversity. This suggests that DNA samples archived in biobanks should be suitable for retrospective analyses. Three technical replicates per sample (extraction method) were analysed
Project description:Leber2015 - Mucosal immunity and gut
microbiome interaction during C. difficile infection
This model is described in the article:
Systems Modeling of
Interactions between Mucosal Immunity and the Gut Microbiome
during Clostridium difficile Infection.
Leber A, Viladomiu M, Hontecillas R,
Abedi V, Philipson C, Hoops S, Howard B, Bassaganya-Riera
J.
PLoS ONE 2015; 10(7): e0134849
Abstract:
Clostridium difficile infections are associated with the use
of broad-spectrum antibiotics and result in an exuberant
inflammatory response, leading to nosocomial diarrhea, colitis
and even death. To better understand the dynamics of mucosal
immunity during C. difficile infection from initiation through
expansion to resolution, we built a computational model of the
mucosal immune response to the bacterium. The model was
calibrated using data from a mouse model of C. difficile
infection. The model demonstrates a crucial role of T helper 17
(Th17) effector responses in the colonic lamina propria and
luminal commensal bacteria populations in the clearance of C.
difficile and colonic pathology, whereas regulatory T (Treg)
cells responses are associated with the recovery phase. In
addition, the production of anti-microbial peptides by inflamed
epithelial cells and activated neutrophils in response to C.
difficile infection inhibit the re-growth of beneficial
commensal bacterial species. Computational simulations suggest
that the removal of neutrophil and epithelial cell derived
anti-microbial inhibitions, separately and together, on
commensal bacterial regrowth promote recovery and minimize
colonic inflammatory pathology. Simulation results predict a
decrease in colonic inflammatory markers, such as neutrophilic
influx and Th17 cells in the colonic lamina propria, and length
of infection with accelerated commensal bacteria re-growth
through altered anti-microbial inhibition. Computational
modeling provides novel insights on the therapeutic value of
repopulating the colonic microbiome and inducing regulatory
mucosal immune responses during C. difficile infection. Thus,
modeling mucosal immunity-gut microbiota interactions has the
potential to guide the development of targeted fecal
transplantation therapies in the context of precision medicine
interventions.
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Project description:Recent advances in (meta)genomic methods have provided new opportunities to examine host-microbe-environment interactions in the human gut. While opportunities exist to extract DNA from freshly sourced colonic tissue there are potentially valuable sources of DNA from historical studies that might also be examined. We examined how four different tissue DNA extraction methods employed in past clinical trials might impact the recovery of microbial DNA from a colonic tissue sample as assessed using a custom designed phylogenetic microarray for human gut bacteria and archaebacteria. While all methods of DNA extraction produced similar phylogenetic profiles some extraction specific biases were also observed. Real time PCR analysis targeting several bacterial groups substantiated this observation. These data suggest that while the efficacy of different DNA extraction methods differs somewhat all the methods tested produce an accurate representation of microbial diversity. This suggests that DNA samples archived in biobanks should be suitable for retrospective analyses.
2010-01-01 | GSE18420 | GEO
Project description:colonic microbial diversity of HT-treated mice
| PRJNA692252 | ENA
Project description:Study of microbial diversity on mice cecum contents
| PRJNA1085102 | ENA
Project description:Gut microbial diversity in Hyperlipidemia Rats
Project description:Background: Inflammatory bowel diseases (IBD) may be caused in part by aberrant immune responses to commensal intestinal microbes including Bacteroides thetaiotaomicron (B.theta). Healthy, germ-free HLA-B27 transgenic (Tg) rats develop chronic colitis when colonized with complex gut commensal bacteria whereas non-transgenic (nTg) rats remain disease-free. However, the role of B.theta, a well-characterized anaerobic commensal bacterium, in causing disease in Tg rats is unknown nor is much known about how microbes respond to host inflammation. Methods: Tg and nTg rats were monoassociated with a human isolate of B.theta. Colonic inflammation was quantified by blinded histological scoring and real-time RT-PCR assays of pro-inflammatory cytokines. Cecal bacterial concentrations were measured by quantitative plating. Whole genome transcriptional profiling of B.theta recovered from ceca was performed using custom GeneChips and data analyzed using dChip, Significance Analysis of Microarrays, and Gene Set Enrichment Analysis (GSEA) software. Results: B.theta monoassociated Tg rats had significantly more colonic inflammation and increased colonic levels of pro-inflammatory cytokine mRNAs compared to nTg controls. Transcriptional profiles of cecal B.theta were significantly different in Tg vs. nTg rats. GSEA revealed that the Gene Ontology molecular function of receptor activity, which is comprised mainly of genes that encode nutrient binding proteins, was significantly enriched with genes upregulated in B.theta from Tg rats. KEGG canonical pathways of ribosome, oxidative phosphorylation, pyrimidine metabolism, purine metabolism, peptidoglycan biosynthesis, and metabolism were significantly enriched with genes downregulated in B.theta from Tg rats. Numbers of viable bacteria/gram cecal contents in Tg vs. nTg rats were not significantly different. Conclusions: B.theta induces mild colitis in HLA-B27 Tg rats, which is associated with changes in the expression of microbial metabolic and nutrient binding pathways, but no difference in concentrations of luminal bacteria. Mechanistic studies of differentially expressed B.theta genes may reveal novel pathways that contribute to IBD. The fully-sequenced human fecal isolate of B.theta (VPI-5482) was grown on Brain-Heart Infusion (BHI) agar and in BHI broth under strict anaerobic conditions using pre-reduced media. Adult germ-free HLA-B27/b2 microglobulin transgenic rats and adult germ-free non-transgenic littermate were monoassociated with B.theta for six weeks in gnotobiotic isolators at the National Gnotobiotic Rodent Resource Center at UNC Chapel Hill. Bacterial RNA was isolated from rat cecal contents and hybridized on Affymetrix human gut microbiota community GeneChip.