Intestinal DMBT1 expression is modulated by Crohn's disease-associated IL23R variants and by a DMBT1 variant which influences binding of the transcription factors CREB1 and ATF-2

PLoS One. 2013 Nov 5;8(11):e77773. doi: 10.1371/journal.pone.0077773. eCollection 2013.

Abstract

Objectives: DMBT is an antibacterial pattern recognition and scavenger receptor. In this study, we analyzed the role of DMBT1 single nucleotide polymorphisms (SNPs) regarding inflammatory bowel disease (IBD) susceptibility and examined their functional impact on transcription factor binding and downstream gene expression.

Methods: Seven SNPs in the DMBT1 gene region were analyzed in 2073 individuals including 818 Crohn's disease (CD) patients and 972 healthy controls in two independent case-control panels. Comprehensive epistasis analyses for the known CD susceptibility genes NOD2, IL23R and IL27 were performed. The influence of IL23R variants on DMBT1 expression was analyzed. Functional analysis included siRNA transfection, quantitative PCR, western blot, electrophoretic mobility shift and luciferase assays.

Results: IL-22 induces DMBT1 protein expression in intestinal epithelial cells dependent on STAT3, ATF-2 and CREB1. IL-22 expression-modulating, CD risk-associated IL23R variants influence DMBT1 expression in CD patients and DMBT1 levels are increased in the inflamed intestinal mucosa of CD patients. Several DMBT1 SNPs were associated with CD susceptibility. SNP rs2981804 was most strongly associated with CD in the combined panel (p = 3.0 × 10(-7), OR 1.42; 95% CI 1.24-1.63). All haplotype groups tested showed highly significant associations with CD (including omnibus P-values as low as 6.1 × 10(-18)). The most strongly CD risk-associated, non-coding DMBT1 SNP rs2981804 modifies the DNA binding sites for the transcription factors CREB1 and ATF-2 and the respective genomic region comprising rs2981804 is able to act as a transcriptional regulator in vitro. Intestinal DMBT1 expression is decreased in CD patients carrying the rs2981804 CD risk allele.

Conclusion: We identified novel associations of DMBT1 variants with CD susceptibility and discovered a novel functional role of rs2981804 in regulating DMBT1 expression. Our data suggest an important role of DMBT1 in CD pathogenesis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Activating Transcription Factor 2 / metabolism*
  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Base Sequence
  • Binding Sites
  • Case-Control Studies
  • Crohn Disease / genetics
  • Crohn Disease / immunology
  • Crohn Disease / metabolism*
  • Cyclic AMP Response Element-Binding Protein / metabolism*
  • Epistasis, Genetic
  • Female
  • Genetic Association Studies
  • Genetic Predisposition to Disease
  • Humans
  • Interleukins / physiology
  • Male
  • Middle Aged
  • Polymorphism, Single Nucleotide
  • Promoter Regions, Genetic
  • Protein Binding
  • Receptors, Cell Surface / genetics*
  • Receptors, Cell Surface / metabolism
  • Receptors, Interleukin / genetics*
  • Sequence Analysis, DNA
  • Transcriptional Activation
  • Young Adult

Substances

  • ATF2 protein, human
  • Activating Transcription Factor 2
  • CREB1 protein, human
  • Cyclic AMP Response Element-Binding Protein
  • DMBT1 protein, human
  • IL23R protein, human
  • Interleukins
  • Receptors, Cell Surface
  • Receptors, Interleukin
  • interleukin-22

Grant support

JD was supported by a grant from the Ludwig-Maximilians-University of Munich (Promotionsstipendium). SB was supported by grants from the Deutsche Forschungsgemeinschaft (DFG) (BR 1912/6-1), the Else-Kröner-Fresenius-Stiftung (Else Kröner-Exzellenzstipendium 2010_EKES.32) and by grants from the Ludwig-Maximilians-University of Munich (Excellence Initiative, Investment funds 2008 and FöFoLe). TO was supported by DFG grant Ol 324/1-1. AF was supported by the German Ministry of Education and Research through the National Genome Research Network and receives infrastructure support through the DFG cluster of excellence ‘Inflammation at Interfaces’. DC was supported by the Deutsche Forschungsgemeinschaft (German Research Foundation) within the framework of the Munich Cluster for Systems Neurology (EXC 1010 SyNergy). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.