title: Increased in vivo transcription of an IL-8 haplotype associated with respiratory syncytial virus disease-susceptibility.
abstract: Interleukin-8 (IL-8) has been implicated in the pathogenesis of RSV-induced bronchiolitis. Previously, we have described an association between bronchiolitis disease severity and a specific IL-8 haplotype comprising six single-nucleotide polymorphisms (SNPs) (-251A/+396G/+781T/+1238delA/+1633T/+2767T, haplotype 2). Here we investigated the functional basis for this association by measuring haplotype-specific transcription in vivo in human primary cells. We found a significant increase in transcript level derived from the IL-8 haplotype 2 relative to the mirror haplotype 1 (-251T/+396T/+781C/+1238insA/+1633C/+2767A) in respiratory epithelial cells but not in lymphocytes. A promoter polymorphism, -251A, present on the high producer haplotype, had no significant affect on the allele-specific level of transcription when analyzed in reporter gene experiments in human respiratory epithelial A549 cells. We proceeded to systematically screen for allele-specific protein-DNA binding in this functional haplotype, which revealed significant differential binding at the +781T/C polymorphism. C/EBP beta was identified as being part of a transcription factor binding complex that preferentially bound in the presence of the +781 T allele. These results suggest that the mechanism for disease susceptibility to RSV-induced bronchiolitis may occur through a haplotype-specific increase in IL-8 transcription, which may be mediated by functional polymorphisms within that haplotype.
authors.affiliation: Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK. doug.hacking@paediatrics.ox.ac.uk
authors.forename: D
authors.initials: D
authors.lastname: Hacking
authors.forename: J C
authors.initials: JC
authors.lastname: Knight
authors.forename: K
authors.initials: K
authors.lastname: Rockett
authors.forename: H
authors.initials: H
authors.lastname: Brown
authors.forename: J
authors.initials: J
authors.lastname: Frampton
authors.forename: D P
authors.initials: DP
authors.lastname: Kwiatkowski
authors.forename: J
authors.initials: J
authors.lastname: Hull
authors.forename: I A
authors.initials: IA
authors.lastname: Udalova
mesh_terms: D002467:Cell Nucleus / Q000378:metabolism; D020022:Genetic Predisposition to Disease; D006239:Haplotypes; D006801:Humans; D016209:Interleukin-8 / Q000235:genetics* / Q000378:metabolism; D009687:Nuclear Proteins / Q000378:metabolism; D011401:Promoter Regions, Genetic; D018357:Respiratory Syncytial Virus Infections / Q000235:genetics* / Q000378:metabolism; D012136:Respiratory Syncytial Viruses / Q000378:metabolism; D017422:Sequence Analysis, DNA; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D016209:Interleukin-8; D009687:Nuclear Proteins; C439524:TNF protein, human; D014409:Tumor Necrosis Factor-alpha