Wang Xiao-Hua, Shu Jin, Jiang Chun-Ming, Zhuang Li-Li, Yang Wei-Xia, Zhang Hui-Weng, Wang Lu-Lu, Li Lin, Chen Xiao-Qing, Jin Rui, Zhou Guo-Ping
Department of Pediatrics, The First Affiliated Hospital, Nanjing Medical University, 300 Guang Zhou Road, Nanjing, Jiangsu Province 210029, China; Department of Pediatrics, Nanjing First Hospital, Nanjing Medical University, 68 Chang Le Road, Nanjing, Jiangsu Province 210006, China.
Department of Pediatrics, The First Affiliated Hospital, Nanjing Medical University, 300 Guang Zhou Road, Nanjing, Jiangsu Province 210029, China.
Int J Biochem Cell Biol. 2017 Jun;87:8-17. doi: 10.1016/j.biocel.2017.03.007. Epub 2017 Mar 20.
Respiratory syncytial virus (RSV) is the leading cause of bronchiolitis in infancy, which is a major risk factor for recurrent wheezing and asthma. Orosomucoid 1-like protein 3 (ORMDL3) has been reported to associate with virus-triggered recurrent wheezing and asthma in children. However, little is known about how ORMDL3 is involved into RSV infection. In this study, we showed that the mRNA expression of ORMDL3 is significantly increased in the peripheral blood lymphocytes of infants with RSV-induced bronchiolitis compared with uninfected controls, also increased in bronchial epithelial cells and lung fibroblasts following RSV infection in vitro. To investigate the underlying mechanisms of RSV-induced ORMDL3 expression, we performed in silico analysis of the binding sites of several transcription factors in the ORMDL3 promoter. The proximal interferon-regulatory factor-3 (IRF-3) binding site positively regulated ORMDL3 transcription following exposure to RSV, as determined through mutational analysis. Overexpression and RNA interference experiments targeting IRF-3 showed that it regulates the expression of ORMDL3 following RSV exposure. Electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP) assay showed that IRF-3 binds directly to the promoter of the ORMDL3 gene. Furthermore, we confirmed that expression of IRF-3 is significantly increased and shows a strong linear correlation with increased ORMDL3 in the peripheral blood lymphocytes from infants with RSV-induced bronchiolitis. Our results indicate that IRF-3 is an important regulator of ORMDL3 induction following RSV infection by binding directly to the promoter of ORMDL3, which may be implicated in the inflammatory and immune reactions involved in bronchiolitis and wheezing diseases.
呼吸道合胞病毒（RSV）是婴儿期细支气管炎的主要病因，而细支气管炎是反复喘息和哮喘的主要危险因素。据报道，类orosomucoid 1蛋白3（ORMDL3）与儿童病毒引发的反复喘息和哮喘有关。然而，关于ORMDL3如何参与RSV感染知之甚少。在本研究中，我们发现，与未感染的对照组相比，RSV诱发的细支气管炎婴儿外周血淋巴细胞中ORMDL3的mRNA表达显著增加，在体外RSV感染后的支气管上皮细胞和肺成纤维细胞中也增加。为了研究RSV诱导ORMDL3表达的潜在机制，我们对ORMDL3启动子中几种转录因子的结合位点进行了计算机分析。通过突变分析确定，近端干扰素调节因子3（IRF-3）结合位点在暴露于RSV后正向调节ORMDL3转录。针对IRF-3的过表达和RNA干扰实验表明，它在RSV暴露后调节ORMDL3的表达。电泳迁移率变动分析（EMSA）和染色质免疫沉淀（ChIP）分析表明，IRF-3直接结合到ORMDL3基因的启动子上。此外，我们证实，在RSV诱发的细支气管炎婴儿的外周血淋巴细胞中，IRF-3的表达显著增加，并且与ORMDL3的增加呈强线性相关。我们的结果表明，IRF-3通过直接结合到ORMDL3的启动子上，是RSV感染后ORMDL3诱导的重要调节因子，这可能与细支气管炎和喘息性疾病中的炎症和免疫反应有关。
