Wagoner Jessica, Austin Michael, Green Jamison, Imaizumi Tadaatsu, Casola Antonella, Brasier Allan, Khabar Khalid S A, Wakita Takaji, Gale Michael, Polyak Stephen J
Department of Laboratory Medicine, University of Washington, Virology 359690, 325 9th Avenue, Seattle, WA 98104-2499, USA.
J Virol. 2007 Jan;81(1):309-18. doi: 10.1128/JVI.01411-06. Epub 2006 Oct 11.
Hepatitis C virus (HCV) infection induces the alpha-chemokine interleukin-8 (CXCL-8), which is regulated at the levels of transcription and mRNA stability. In the current study, CXCL-8 regulation by double-stranded (ds)RNA pathways was analyzed in the context of HCV infection. A constitutively active mutant of the retinoic acid-inducible gene I (RIG-I), RIG-N, activated CXCL-8 transcription. Promoter mutagenesis experiments indicated that NF-kappaB and interferon (IFN)-stimulated response element (ISRE) binding sites were required for the RIG-N induction of CXCL-8 transcription. IFN-beta promoter stimulator 1 (IPS-1) expression also activated CXCL-8 transcription, and mutations of the ISRE and NF-kappaB binding sites reduced and abrogated CXCL-8 transcription, respectively. In the presence of wild-type RIG-I, transfection of JFH-1 RNA or JFH-1 virus infection of Huh7.5.1 cells activated the CXCL-8 promoter. Expression of IFN regulatory factor 3 (IRF-3) stimulated transcription from both full-length and ISRE-driven CXCL-8 promoters. Chromatin immunoprecipitation assays demonstrated that IRF-3 and NF-kappaB bound directly to the CXCL-8 promoter in response to virus infection and dsRNA transfection. RIG-N stabilized CXCL-8 mRNA via the AU-rich element in the 3' untranslated region of CXCL-8 mRNA, leading to an increase in its half-life following tumor necrosis factor alpha induction. The data indicate that HCV infection triggers dsRNA signaling pathways that induce CXCL-8 via transcriptional activation and mRNA stabilization and define a regulatory link between innate antiviral and inflammatory cellular responses to virus infection.
丙型肝炎病毒（HCV）感染可诱导α-趋化因子白细胞介素-8（CXCL-8），其在转录水平和mRNA稳定性方面受到调控。在本研究中，在HCV感染的背景下分析了双链（ds）RNA途径对CXCL-8的调控。视黄酸诱导基因I（RIG-I）的组成型活性突变体RIG-N可激活CXCL-8转录。启动子诱变实验表明，NF-κB和干扰素（IFN）刺激反应元件（ISRE）结合位点是RIG-N诱导CXCL-8转录所必需的。IFN-β启动子刺激因子1（IPS-1）的表达也可激活CXCL-8转录，而ISRE和NF-κB结合位点的突变分别降低和消除了CXCL-8转录。在存在野生型RIG-I的情况下，转染JFH-1 RNA或用JFH-1病毒感染Huh7.5.1细胞可激活CXCL-8启动子。干扰素调节因子3（IRF-3）的表达可刺激全长和ISRE驱动的CXCL-8启动子的转录。染色质免疫沉淀实验表明，IRF-3和NF-κB在病毒感染和dsRNA转染后直接结合到CXCL-8启动子上。RIG-N通过CXCL-8 mRNA 3'非翻译区的富含AU元件稳定CXCL-8 mRNA，导致肿瘤坏死因子α诱导后其半衰期增加。数据表明，HCV感染触发dsRNA信号通路，通过转录激活和mRNA稳定诱导CXCL-8，并确定了先天性抗病毒和炎症细胞对病毒感染反应之间的调控联系。
