Enterovirus 71 Inhibits Cellular Type I Interferon Signaling by Downregulating JAK1 Protein Expression
Enterovirus 71 Inhibits Cellular Type I Interferon Signaling by Downregulating JAK1 Protein Expression
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DOI：
10.1089/vim.2013.0127
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发表时间：
2014-08-01
期刊：
影响因子：
2.2
通讯作者：
Chen, Wei
中科院分区：
文献类型：
--
作者：
Liu, Ying;Zhang, Zhe;Chen, Wei
肠道病毒71型（EV 71）感染可导致严重的疾病，并导致儿童死亡。一些国家报告了EV 71的反复暴发。干扰素（IFN）已被用于治疗几种类型的病毒感染几十年，但具有有限的能力，以抑制EV 71复制。在此，我们打算研究EV 71抑制细胞I型IFN应答的机制。在这项研究中，MRC-5（人胚肺成纤维细胞）或RD（人横纹肌肉瘤）细胞感染EV 71，然后用或不用IFN-α 2b处理。收获细胞并通过流式细胞术分析以确定IFNAR 1的水平。制备细胞裂解物以通过蛋白质印迹法检测STAT 1、STAT 2、磷酸化STAT 1、磷酸化STAT 2、IFNAR 1、JAK 1和TYK 2的水平。在EV 71感染的细胞中，IFN诱导的STAT 1和STAT 2的磷酸化被抑制，而IFNAR 1没有显著下调。EV 71诱导的STAT 1和STAT 2磷酸化的抑制不被蛋白酪氨酸磷酸酶抑制剂所拯救，并且不依赖于细胞因子信号蛋白1/3水平的抑制剂。JAK 1和TYK 2的磷酸化被抑制，同时EV 71诱导JAK 1的下调，这发生在转录后水平，并且不依赖于蛋白酶体。JAK 1的表达没有减少，IFN-α刺激的STAT 1和STAT 2磷酸化在过表达EV 71病毒蛋白2A或3C的HEK 293 T细胞中没有被阻断。这项研究表明，EV 71通过下调JAK 1抑制细胞I型IFN抗病毒途径，而IFNAR 1的表达在EV 71感染的细胞中没有显著改变。另外，EV 71病毒蛋白2A和3C不作为细胞I型IFN信号传导的拮抗剂。
Enterovirus 71 (EV71) infection can cause severe disease and lead to death in children. Recurring outbreaks of EV71 have been reported in several countries. Interferons (IFNs) have been used for decades to treat several types of viral infection, but have a limited ability to inhibit EV71 replication. Herein, we intend to investigate the mechanisms by which EV71 inhibits the cellular type I IFN response. In this study, MRC-5 (human embryonic lung fibroblast) or RD (human rhabdomyosarcoma) cells were infected with EV71, and then treated with or without IFN-alpha 2b. Cells were harvested and analyzed by flow cytometry to determine the level of IFNAR1. Cell lysis were prepared to detect the levels of STAT1, STAT2, phosphorylated STAT1, phosphorylated STAT2, IFNAR1, JAK1, and TYK2 by Western blotting. The phosphorylation of STAT1 and STAT2 induced by IFN were inhibited without significant downregulation of IFNAR1 in EV71-infected cells. The EV71-induced suppression of STAT1 and STAT2 phosphorylation was not rescued by the protein tyrosine phosphatases inhibitor, and was independent of suppressor of cytokine signaling protein 1/3 levels. The phosphorylation of JAK1 and TYK2 were inhibited accompanied by EV71-induced downregulation of JAK1, which occurred at a post-transcriptional level and was proteasome independent. JAK1 expression did not decrease, and IFN-alpha-stimulated STAT1 and STAT2 phosphorylation were not blocked in HEK293T cells overexpressing the EV71 viral protein 2A or 3C. This study demonstrates that EV71 inhibits the cellular type I IFN antiviral pathway by downregulating JAK1, while the expression of IFNAR1 does not significantly alter in EV71-infected cells. Additionally, the EV71 viral proteins 2A and 3C do not act as antagonists of cellular type I IFN signaling.