Engineering Research Center of Ecology and Agricultural Use of Wetland, Ministry of Education, Jingzhou 434020, China; State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei Province 430072, China.
Engineering Research Center of Ecology and Agricultural Use of Wetland, Ministry of Education, Jingzhou 434020, China.
Fish Shellfish Immunol. 2018 Jan;72:31-36. doi: 10.1016/j.fsi.2017.10.042. Epub 2017 Dec 5.
In mammals, type I interferons (IFNs) are primarily regulated by transcription factors of the IFN regulatory (IRF) family. Interferon regulatory factor 5 (IRF-5) plays pivotal roles in antiviral and inflammatory responses. In the present study, we found that zebrafish (Danio rerio) IRF5 is a key player in the regulation of the expression of type I IFN and its antiviral immune response. IRF5 was upregulated in zebrafish embryonic fibroblast cells (ZF4) when challenged with grass carp reovirus (GCRV). Moreover, the expression profiles of Mx, IFN, Viperin, and IRF7, but not IRF3, were upregulated by overexpression of IRF5 in Epithelioma papulosum cyprinid cells (EPCs). Luciferase assays revealed that the activation of the IFNϕ1 promoter was stimulated by overexpression of IRF5 and IRF5-△IAD (IRF5 lacking the IRF-associated domain), respectively. However, overexpression of IRF5 or IRF5-△IAD inhibited the activity of the IFNϕ3 promoter. IRF5-△DBD (lacking the DNA-binding domain) had no influence in the activation of the IFNϕ1 and IFNϕ3 promoters. Furthermore, the determination of the cytopathic effect (CPE) numbers and viral titers revealed that the viral concentration was reduced by ectopic expression of IRF5 in EPC cells. Ectopic expression of IRF5 in EPC cells could protect cells from GCRV and significantly inhibited GCRV virus replication. These data indicated that IRF5 could limit viral replication through an IFN-dependent pathway.
在哺乳动物中，I 型干扰素（IFN）主要受 IFN 调节因子（IRF）家族的转录因子调控。干扰素调节因子 5（IRF-5）在抗病毒和炎症反应中发挥关键作用。在本研究中，我们发现斑马鱼（Danio rerio）IRF5 是调节 I 型 IFN 及其抗病毒免疫反应表达的关键因子。草鱼呼肠孤病毒（GCRV）感染斑马鱼胚胎成纤维细胞（ZF4）时，IRF5 上调。此外，在 Epithelioma papulosum cyprinid 细胞（EPC）中过表达 IRF5 可上调 Mx、IFN、Viperin 和 IRF7 的表达谱，但不包括 IRF3。荧光素酶报告基因分析显示，IRF5 和 IRF5-△IAD（缺乏 IRF 相关结构域的 IRF5）分别可刺激 IFNϕ1 启动子的激活。然而，IRF5 或 IRF5-△IAD 的过表达均抑制了 IFNϕ3 启动子的活性。IRF5-△DBD（缺乏 DNA 结合域）对 IFNϕ1 和 IFNϕ3 启动子的激活没有影响。此外，通过测定细胞病变效应（CPE）数和病毒滴度发现，EPC 细胞中 IRF5 的异位表达可降低病毒浓度。EPC 细胞中 IRF5 的异位表达可保护细胞免受 GCRV 感染，并显著抑制 GCRV 病毒复制。这些数据表明，IRF5 可通过 IFN 依赖途径限制病毒复制。
