Schedel Michaela, Pinto Leonardo A, Schaub Bianca, Rosenstiel Philip, Cherkasov Dmitry, Cameron Lisa, Klopp Norman, Illig Thomas, Vogelberg Christian, Weiland Stephan K, von Mutius Erika, Lohoff Michael, Kabesch Michael
University Children's Hospital, Ludwig Maximilian's University Munich, Lindwurmstrasse 4, D-80337 München, Germany.
Am J Respir Crit Care Med. 2008 Mar 15;177(6):613-21. doi: 10.1164/rccm.200703-373OC. Epub 2007 Dec 13.
The development of atopic diseases is characterized by skewed immune responses to common allergens. Only recently, interferons have been identified to play a crucial role in these mechanisms.
Because interferon regulatory factor (IRF)-1 is critical for interferon expression, we tested the hypotheses that genetic changes in this essential transcription factor may have consequences for the development of atopy.
The IRF-1 gene locus was resequenced in 80 human chromosomes. Association and haplotype analyses were performed in a cross-sectional study population of German children from Dresden (n = 1,940), and results were replicated in a second population sample from Munich (n = 1,159), both part of the ISAAC (International Study of Asthma and Allergy in Childhood) phase II. Promoter polymorphism effects were studied using electrophoretic mobility shift assay and colorimetric binding assays. Allele-specific IRF-1 gene expression was studied in vitro using luciferase reporter assays, whereas we assessed ex vivo expression of IRF-1 by real-time polymerase chain reaction and IFN-gamma protein by Luminex technology (Bio-Rad, Hercules, CA). Statistical analyses were performed using SAS/Genetics (SAS 9.1.3; SAS Institute, Cary, NC).
By resequencing, 49 polymorphisms were identified within the IRF-1 gene. Four blocks containing 11 polymorphisms were significantly associated with atopy, total IgE levels, or specific IgE levels in both populations (P < 0.05). Two polymorphisms changed transcription factor binding of nuclear factor (NF)-kappaB and EGR1 (early growth response 1) to the IRF-1 promoter, altered gene expression in vitro (P = 0.0004), and altered IRF-1 mRNA and IFN-gamma protein expression ex vivo.
Our results suggest that functionally relevant IRF-1 polymorphisms influence atopy risk, potentially by altering transcription factor binding, IRF-1 gene expression, and IFN-gamma regulation.
特应性疾病的发展以对常见过敏原的免疫反应失衡为特征。直到最近，干扰素才被确定在这些机制中起关键作用。
由于干扰素调节因子（IRF）-1对干扰素表达至关重要，我们检验了以下假设：这个关键转录因子的基因变化可能对特应性的发展产生影响。
对80条人类染色体上的IRF-1基因座进行重测序。在来自德累斯顿的德国儿童横断面研究人群（n = 1940）中进行关联分析和单倍型分析，并在来自慕尼黑的第二个样本（n = 1159）中重复结果，这两个样本均为国际儿童哮喘和过敏研究（ISAAC）第二阶段的一部分。使用电泳迁移率变动分析和比色结合分析研究启动子多态性的影响。使用荧光素酶报告基因分析体外研究等位基因特异性IRF-1基因表达，而我们通过实时聚合酶链反应和Luminex技术（Bio-Rad，Hercules，CA）评估IRF-1的体外表达和IFN-γ蛋白。使用SAS/Genetics（SAS 9.1.3；SAS Institute，Cary，NC）进行统计分析。
通过重测序，在IRF-1基因内鉴定出49个多态性。在两个群体中，包含11个多态性的4个区域与特应性、总IgE水平或特异性IgE水平显著相关（P < 0.05）。两个多态性改变了核因子（NF）-κB和早期生长反应1（EGR1）与IRF-1启动子的转录因子结合，在体外改变了基因表达（P = 0.0004），并在体外改变了IRF-1 mRNA和IFN-γ蛋白表达。
我们的结果表明，功能相关的IRF-1多态性可能通过改变转录因子结合、IRF-1基因表达和IFN-γ调节来影响特应性风险。
