Kim Sae-Hoon, Lim Kyung-Hwan, Park Han-Ki, Lee Suh-Young, Kim Soon-Hee, Kang Hye-Ryun, Park Heung-Woo, Chang Yoon-Seok, Cho Sang-Heon
Department of Internal Medicine, Seoul National University College of Medicine, Seoul 110-899, Korea. ; Institute of Allergy and Clinical Immunology, Seoul National University Medical Research Center, Seoul 110-899, Korea. ; Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam 463-707, Korea.
Department of Internal Medicine, Seoul National University College of Medicine, Seoul 110-899, Korea. ; Institute of Allergy and Clinical Immunology, Seoul National University Medical Research Center, Seoul 110-899, Korea.
Asia Pac Allergy. 2015 Apr;5(2):114-22. doi: 10.5415/apallergy.2015.5.2.114. Epub 2015 Apr 29.
Human rhinoviruses are the major cause of asthma exacerbation in both children and adults. Recently, impaired antiviral interferon (IFN) response in asthmatics has been indicated as a primary reason of the susceptibility to respiratory virus, but the mechanism of defective IFN production is little understood to date. The expression of IFN regulatory factor 7 (IRF7), a transcriptional factor for virus-induced type I IFN production is known to be regulated epigenetically by DNA methylation.
We aimed to investigate the expression of IFN-α, IFN-β, and IRF7 in response to rhinovirus infection in the adult asthmatics and evaluate DNA methylation status of IRF7 gene promotor.
Twenty symptomatic adult asthmatics and 10 healthy subjects were enrolled and peripheral blood was collected from each subject. Peripheral blood mononuclear cells (PBMCs) were isolated, cultured, and ex vivo stimulated with rhinovirus-16. The mRNA expressions of IFN-α, IFN-β, and IRF7 were analyzed using real time quantitative polymerase chain reaction. Genomic DNA was isolated from untreated PBMCs and the methylation status of IRF7 gene promotor was investigated using bisulfite pyrosequencing.
The mean age of asthmatics was 45.4 ± 15.7 years and 40% was male, which were not different with those of control group. Asthmatics showed significantly decreased mRNA expressions (relative expression to beta-actin) of IFN-α and IFN-β compared with normal control. The mRNA expression of IRF7 in the asthmatics was also significantly lower than those in the normal control. No significant difference of DNA methylation was observed between asthmatics and controls in all analyzed positions of IRF7 promotor CpG loci.
The mRNA expression of type I IFN in response to rhinovirus was impaired in the PBMCs of adult asthmatics. The mRNA expression of IRF7, transcriptional factor inducing type I IFN was also reduced, but not caused by altered DNA methylation in the IRF7 gene promotor.
人鼻病毒是儿童和成人哮喘加重的主要原因。最近，哮喘患者抗病毒干扰素（IFN）反应受损被认为是易患呼吸道病毒的主要原因，但迄今为止，IFN产生缺陷的机制尚不清楚。干扰素调节因子7（IRF7）是病毒诱导的I型IFN产生的转录因子，其表达已知受DNA甲基化的表观遗传调控。
我们旨在研究成年哮喘患者对鼻病毒感染的反应中IFN-α、IFN-β和IRF7的表达，并评估IRF7基因启动子的DNA甲基化状态。
招募20名有症状的成年哮喘患者和10名健康受试者，采集每位受试者的外周血。分离外周血单个核细胞（PBMC），进行培养，并用鼻病毒-16进行体外刺激。使用实时定量聚合酶链反应分析IFN-α、IFN-β和IRF7的mRNA表达。从未经处理的PBMC中分离基因组DNA，使用亚硫酸氢盐焦磷酸测序研究IRF7基因启动子的甲基化状态。
哮喘患者的平均年龄为45.4±15.7岁，男性占40%，与对照组无差异。与正常对照组相比，哮喘患者的IFN-α和IFN-β的mRNA表达（相对于β-肌动蛋白的相对表达）显著降低。哮喘患者中IRF7的mRNA表达也显著低于正常对照组。在IRF7启动子CpG位点的所有分析位置，哮喘患者和对照组之间未观察到DNA甲基化的显著差异。
成年哮喘患者的PBMC中，对鼻病毒反应的I型IFN的mRNA表达受损。诱导I型IFN的转录因子IRF7的mRNA表达也降低，但不是由IRF7基因启动子中DNA甲基化改变引起的。
