The transcription start site and enhancer landscape of the descending colon in inflammatory bowel disease
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ABSTRACT: Inflammatory bowel disease (IBD) is a common and chronic gut disorder, with two subtypes: Crohn's disease (CD) and ulcerative colitis (UC), which are challenging to diagnose. The molecular pathology IBD is not well understood, and the underlying gene regulatory regions have not been comprehensively investigated. Relatedly, most IBD-associated SNPs are located in non-coding regions, and may effect gene regulation. Here, we profiled genome-wide promoter and enhancer activity in the descending colon of IBD patients. IBD-induced enhancer and promoters are highly enriched for IBD-associated SNPs, and can predict IBD diagnosis with an accuracy of 85% in an external cohort.
Project description:Background & Aims: The contribution of genetics to the pathogenesis of inflammatory bowel disease (IBD) has been established by twin studies, targeted sequencing and genome-wide association studies (GWASs). This has yielded a plethora of risk loci with an aim to identify causal variants. Research on the genetic components of IBD has mainly focused on protein coding genes, thereby omitting other functional elements in the human genome i.e. the regulatory regions. Methods: Using acetylated histone 3 lysine 27 (H3K27ac) chromatin immunoprecipitation and sequencing (ChIP-seq), we identified tens of thousands of potential regulatory regions that are active in intestinal epithelium and immune cells, the main cell types involved in IBD. We correlated these regions with susceptibility loci for IBD. Results: We show that 45 out of 163 single nucleotide polymorphisms (SNPs) associated with IBD co-localize with active regulatory elements. In addition, another 47 IBD associated SNPs co-localize with active regulatory element via other SNP in strong linkage disequilibrium. Altogether 92 out of 163 IBD-associated SNPs can be connected with distinct regulatory element. This is 2.5 to 3.5 times more frequent than expected from random sampling. The genomic variation in these SNPs often creates or disrupts known binding motifs - thereby possibly affecting the binding affinity of transcriptional regulators and altering the expression of regulated genes. Conclusions: We show that in addition to protein coding genes, non-coding DNA regulatory regions, active in immune cells and in intestinal epithelium, are involved in IBD. H3K27ac ChIP-seq (ab4729, Abcam) profile of 7 intestinal epithelial samples
Project description:Biopsies from the descending colon were obtained colonoscopically from 46 Crohn's disease patients (33 from areas without inflammation and 18 from inflamed areas). Gene profiling analyses were performed using Human Genome U133 Plus 2.0 GeneChip Array. Hybridization data were analyzed with dChip software.
Project description:Background & Aims: The contribution of genetics to the pathogenesis of inflammatory bowel disease (IBD) has been established by twin studies, targeted sequencing and genome-wide association studies (GWASs). This has yielded a plethora of risk loci with an aim to identify causal variants. Research on the genetic components of IBD has mainly focused on protein coding genes, thereby omitting other functional elements in the human genome i.e. the regulatory regions. Methods: Using acetylated histone 3 lysine 27 (H3K27ac) chromatin immunoprecipitation and sequencing (ChIP-seq), we identified tens of thousands of potential regulatory regions that are active in intestinal epithelium and immune cells, the main cell types involved in IBD. We correlated these regions with susceptibility loci for IBD. Results: We show that 45 out of 163 single nucleotide polymorphisms (SNPs) associated with IBD co-localize with active regulatory elements. In addition, another 47 IBD associated SNPs co-localize with active regulatory element via other SNP in strong linkage disequilibrium. Altogether 92 out of 163 IBD-associated SNPs can be connected with distinct regulatory element. This is 2.5 to 3.5 times more frequent than expected from random sampling. The genomic variation in these SNPs often creates or disrupts known binding motifs - thereby possibly affecting the binding affinity of transcriptional regulators and altering the expression of regulated genes. Conclusions: We show that in addition to protein coding genes, non-coding DNA regulatory regions, active in immune cells and in intestinal epithelium, are involved in IBD.
Project description:The IBD-Character cohort (Edinburgh, Oslo, Örebro, Linköping, Zaragoza, Maastricht) included patients with inflammatory bowel diseases (IBD: Crohn's disease, ulcerative colitis) recruited at diagnosis and non-IBD controls. Paired-end RNA sequencing was used for whole blood expression profiling. Raw and normalized counts tables are provided.
Project description:Studying differences in responders and non-responders to therapy in inflammatory bowel disease (IBD) patients (crohn's disease and ulcerative colitis)
Project description:Hypothesis: Gene expression differences in biopsies from patients with inflammatory bowel disease can be used to identify molecular heterogeneity within patients with active disease. Methods: Patients with a diagnosis of Crohn's disease, ulcerative colitis or normal healthy controls (with or without infectious colitis) underwent ileocolonoscopy. In healthy controls, biopsies were taken in the sigmoid colon (n=21), ascending/descending colon (n=25) and the terminal ileum (n=12). In patients with Crohn's disease, biopsies were taken in the ascending/descending colon (n=107) and terminal ileum (n=70) in uninflamed areas in all patients; in patients with mucosal lesions, additional biopsies were taken in inflamed regions of the ascending/descending colon (n=35) and terminal ileum (n=55). In ulcerative colitis patients, paired uninflamed sigmoid (n=48) and inflamed sigmoid biopsies (n=46) were taken. Biopsies were placed in RNAlater at the clinical site, frozen and shipped to Genentech, where they were disrupted using TissueLyzer beads, then RNA was isolated using RNeasy columns. RNA was hybridized to Agilent human 4x44kv1 arrays, dual channel, using universal reference.
Project description:We report ileum gene expression of 37 controls and 158 patients with either Crohn's disease (n=112), ulcerative colitis (n=44), unclassifed IBD (1), or IBS (1). We contrast gene expression in African American (n=104) versus white (n=25) CD and UC patients.
Project description:Characterizing the proteomic profile of extracellular vesicles isolated from the descending colon of pediatric patients with inflammatory bowel disease and control participants
Project description:Gut dysbiosis is closely involved in the pathogenesis of inflammatory bowel disease (IBD). However, it remains unclear whether IBD-associated gut dysbiosis plays a primary role in disease manifestation or is merely secondary to intestinal inflammation. Here, we established a humanized gnotobiotic (hGB) mouse system to assess the functional role of gut dysbiosis associated with two types of IBD - Crohn's disease (CD) and ulcerative colitis (UC). In order to explore the functional impact of dysbiotic microbiota in IBD patients on host immune responses, we analyzed gene expression profiles in colonic mucosa of hGB mice colonized with healty (HC), CD, and UC microbiota.
Project description:We report whole blood gene expression of 12 healthy controls and 190 patients with either oligoarticular (n=43), polyarticular (n=46), or systemic JIA (n=26), or Crohn's disease (n=60) and ulcerative colitis (n=15). The subtypes of JIA are characterized by a gradient of differential gene expression ranging from controls to oligoJIA, polyJIA, sJIA, and IBD.