Inflammatory bowel disease risk loci overlap with DNA regulatory regions in immune cells and intestinal epithelium

ABSTRACT: 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

ORGANISM(S): Homo sapiens

SUBMITTER: Michal Mokry 

PROVIDER: E-GEOD-51425 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress