1. An ankylosing spondylitis-associated genetic variant in the IL23R-IL12RB2 intergenic region modulates enhancer activity and is associated with increased Th1-cell differentiation
- Author
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Roberts, AR, Vecellio, M, Chen, L, Ridley, A, Cortes, A, Knight, JC, Bowness, P, Cohen, CJ, and Wordsworth, BP
- Subjects
Adult ,Male ,Genotype ,T Cells ,Ankylosing Spondylitis ,Receptors, Interleukin-12 ,Genetic Variation ,Cell Differentiation ,Receptors, Interleukin ,Th1 Cells ,Flow Cytometry ,Polymorphism, Single Nucleotide ,HEK293 Cells ,Gene Polymorphism ,Humans ,DNA, Intergenic ,Female ,Spondylitis, Ankylosing ,Basic and Translational Research ,Alleles ,Genetic Association Studies - Abstract
Objectives To explore the functional basis for the association between ankylosing spondylitis (AS) and single-nucleotide polymorphisms (SNPs) in the IL23R-IL12RB2 intergenic region. Methods We performed conditional analysis on genetic association data and used epigenetic data on chromatin remodelling and transcription factor (TF) binding to identify the primary AS-associated IL23R-IL12RB2 intergenic SNP. Functional effects were tested in luciferase reporter assays in HEK293T cells and allele-specific TF binding was investigated by electrophoretic mobility gel shift assays. IL23R and IL12RB2 mRNA levels in CD4+ T cells were compared between cases homozygous for the AS-risk ‘A’ allele and the protective ‘G’ allele. The proportions of interleukin (IL)-17A+ and interferon (IFN)-γ+ CD4+ T-cells were measured by fluorescence-activated cell sorting and compared between these AS-risk and protective genotypes. Results Conditional analysis identified rs11209032 as the probable causal SNP within a 1.14 kb putative enhancer between IL23R and IL12RB2. Reduced luciferase activity was seen for the risk allele (p Conclusions The rs11209032 SNP downstream of IL23R forms part of an enhancer, allelic variation of which may influence Th1-cell numbers. Homozygosity for the risk ‘A’ allele is associated with more IFN-γ-secreting (Th1) cells. Further work is necessary to explain the mechanisms for these important observations.
- Published
- 2016