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Genome-wide expression profiling implicates a MAST3-regulated gene set in colonic mucosal inflammation of ulcerative colitis patients.

ABSTRACT: Crohn's disease (CD) and ulcerative colitis (UC) are inflammatory bowel diseases (IBDs) presumably caused by dysregulated immune responses to the gut microbiota. Genetic association studies have implicated dozens of chromosomal regions or loci in IBD susceptibility. The next challenge is to explain the individual role of each of these modest effect loci in the disease state. We have previously identified MAST3 as an IBD susceptibility gene through genetic fine-mapping of the 19p linkage region. Testing MAST3 in a reporter assay provided preliminary evidence that MAST3 modulates the activity of inflammation-related transcription factor nuclear factor kappa B.Here we characterized the function of MAST3 through an examination of the influence of the modulation of MAST3 expression on endogenous genome-wide expression patterns. More specifically, we looked at differential gene expression resulting from overexpression and knockdown of the MAST3 gene in epithelial and macrophage cell lines. From we highlight a group of genes whose expression is modulated by MAST3 and correlate their expression with NF-jB activity. Their expression was found to be enriched in inflamed mucosal tissue of UC patients, confirming the importance of these genes in IBD.We highlight a group of genes whose expression is modulated by MAST3 and correlate their expression with NF-?B activity. Their expression was found to be enriched in inflamed mucosal tissue of UC patients, confirming the importance of these genes in IBD. These MAST3-regulated genes are central to mucosal immune responses. Among them are proinflammatory cytokines (e.g., CCL20, IL8), regulators of NF-?B (e.g., TNFAIP3, LY96, NFKBIA), genes involved in interferon-induced defense against pathogen invasion (e.g., IFIT1, ISG15), and genes involved in cell adhesion and/or migration (e.g., CD44, TMOD1).Taken together, these results confirm MAST3 as a modulator of the inflammatory response through regulation of immune gene expression in the gut of IBD patients.

SUBMITTER: Labbe C

PROVIDER: S-EPMC3269563 | biostudies-literature | 2012 Jun

REPOSITORIES: biostudies-literature

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Genome-wide expression profiling implicates a MAST3-regulated gene set in colonic mucosal inflammation of ulcerative colitis patients.

Labbé Catherine C Boucher Gabrielle G Foisy Sylvain S Alikashani Azadeh A Nkwimi Herbert H David Geneviève G David Geneviève G Beaudoin Mélissa M Goyette Philippe P Charron Guy G Xavier Ramnik J RJ Rioux John D JD

Inflammatory bowel diseases 20111012 6

<h4>Background</h4>Crohn's disease (CD) and ulcerative colitis (UC) are inflammatory bowel diseases (IBDs) presumably caused by dysregulated immune responses to the gut microbiota. Genetic association studies have implicated dozens of chromosomal regions or loci in IBD susceptibility. The next challenge is to explain the individual role of each of these modest effect loci in the disease state. We have previously identified MAST3 as an IBD susceptibility gene through genetic fine-mapping of the 1 ...[more]

PMID: 21994190

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Project description:BackgroundWe aimed to identify the risk factors associated with colonic cytomegalovirus (CMV) infection in ulcerative colitis (UC) and to compare the clinical course between antiviral therapy-treated and -untreated groups in mucosal CMV-polymerase chain reaction (PCR) -positive cases.MethodsWe retrospectively selected 46 UC patients (>15 years old) in active phase who underwent colonoscopy with biopsy and were analyzed for CMV infection by mucosal PCR between October 2011 and December 2015 at our institution. Colonic CMV in inflamed mucosa was detected using quantitative real-time PCR. The clinical course was evaluated, including need for drug therapy/surgery or drug therapy intensification. In addition, we evaluated the clinical course between CMV-DNA- cases and CMV-DNA+ cases with low viral load.ResultsAt baseline, CMV-DNA+ patients were significantly older, had higher endoscopic scores, and required higher corticosteroid doses during the past 4 weeks than CMV-DNA- patients (p< 0.05). No significant differences were observed in disease duration, disease distribution, laboratory data, or use of other medication between CMV-DNA+ and CMV-DNA- patients. In the anti-CMV-treated group with a median (range) DNA load of 16,000 (9,000-36,400), 3patients achieved remission without additional UC therapy, 2 required additional UC therapy, and 1 required colectomy despite azathioprine and infliximab therapy. In the CMV-untreated group with a median (range) DNA load of 919 (157-5,480), all patients achieved remission with UC therapy alone. No significant difference was observed in the clinical course between CMV-DNA- cases and CMV-DNA+ cases with low viral loads.ConclusionsAging, endoscopic UC activity, and corticosteroid dose predispose to colonic CMV infection, as determined by mucosal PCR, in UC. UC treatment without anti-CMV therapy may be warranted, particularly in patients with low-load CMV-DNA. Anti-CMV therapy alone does not always achieve clinical response in UC even in cases with high-load PCR.

Project description:Background and aims: Mucosal abnormalities are potentially important in the primary pathogenesis of ulcerative colitis (UC). We investigated the mucosal transcriptomic expression profiles of biopsies from patients with UC and healthy controls (HC), taken from macroscopically non-inflamed tissue from the terminal ileum and three colonic locations with the objective of identifying abnormal molecules that might be involved in disease development. Methods: Whole-genome transcriptional analysis was performed on intestinal biopsies taken from 24 UC, 26 HC and 14 patients with CrohnM-bM-^@M-^Ys disease. Differential gene expression analysis was performed at each tissue location separately and results were then meta-analysed using FisherM-bM-^@M-^Ys method. Significantly differentially expressed genes were validated using qPCR. Gene location within the colon was determined using immunohistochemistry, subcellular fractionation, electron and confocal microscopy. DNA methylation was quantified by pyrosequencing. Results: Seven probes were abnormally expressed throughout the colon in UC patients with Family with sequence similarity member 5 C (FAM5C) being the most significantly underexpressed. Attenuated expression of FAM5C in UC was independent of inflammation, unrelated to phenotype or treatment, and remained low at rebiopsy approximately 23 months later. FAM5C is localised to the brush border of the colonic epithelium and expression is influenced by DNA methylation within its promoter. Conclusion: Genome-wide expression analysis of non-inflamed mucosal biopsies from UC patients identified FAM5C as significantly under-expressed throughout the colon in a major sub-set of patients with UC. Low levels of this gene could predispose to or contribute to the maintenance of the characteristic mucosal inflammation seen in this condition. Total RNA was extracted from the intestinal biopsies taken from macroscopically normal mucosa in the rectum, descending colon, ascending colon and terminal ileum in clinically quiescent Ulcerative colitis and Crohn's disease patients and compared to healthy controls. Normalized data for 26,261 probes out of 47,323 only. Criteria for inclusion not specified. The non-normalized matrix contains the complete non-normalized data for all probes.

Dataset Information

Genome-wide expression profiling implicates a MAST3-regulated gene set in colonic mucosal inflammation of ulcerative colitis patients.

Publications

Genome-wide expression profiling implicates a MAST3-regulated gene set in colonic mucosal inflammation of ulcerative colitis patients.

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