Interferon-Induced ISG15 Conjugation Inhibits Influenza A Virus Gene Expression and Replication in Human Cells
Interferon-Induced ISG15 Conjugation Inhibits Influenza A Virus Gene Expression and Replication in Human Cells
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DOI：
10.1128/jvi.01667-08
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发表时间：
2009-06-15
影响因子：
5.4
通讯作者：
Krug, Robert M.
中科院分区：
文献类型：
--
作者：
Hsiang, Tien-Ying;Zhao, Chen;Krug, Robert M.
泛素样ISG15蛋白及其偶联酶是由I型干扰素（ifn）诱导的。使用ISG15敲除（ISG15(-/-)）小鼠进行的实验证实，ISG15和/或其偶联物抑制甲型流感病毒的复制。然而，与小鼠的病毒抑制结果相反，组织培养中ISG15（+/+）和ISG15（-/-）小鼠胚胎成纤维细胞的病毒复制率相似。在这里，我们关注的是人组织培养细胞，以及ISG15和/或其偶联对甲型流感病毒基因在这些细胞中的表达和复制的影响。我们证明，通过使用针对ISG15偶联酶的小干扰rna抑制ISG15偶联酶，ifn诱导的人细胞中甲型流感病毒的抗病毒活性显著降低。通过抑制ISG15结合，ifn诱导的抗甲型流感病毒蛋白合成的抗病毒活性降低了5- 20倍。通过这些siRNA处理恢复的病毒蛋白的数量大约是未用IFN预处理的细胞中产生的数量的40 - 50%。此外，我们发现ISG15偶联物在感染人类细胞后早期抑制甲型流感病毒复制10- 20倍。这些结果表明，ISG15偶联在IFN诱导的人细胞抗病毒状态中发挥了重要作用。相反，我们发现在小鼠胚胎成纤维细胞中，ISG15结合不仅不影响甲型流感病毒的复制，而且也不促进ifn诱导的抗甲型流感病毒基因表达的抗病毒活性。
The ubiquitin-like ISG15 protein, as well as its conjugating enzymes, is induced by type I interferons (IFNs). Experiments using ISG15 knockout (ISG15(-/-)) mice established that ISG15 and/or its conjugation inhibits the replication of influenza A virus. However, in contrast to the virus inhibition results for mice, the rates of virus replication in ISG15(+/+) and ISG15(-/-) mouse embryo fibroblasts in tissue culture were similar. Here we focus on human tissue culture cells and on the effect of ISG15 and/or its conjugation on influenza A virus gene expression and replication in such cells. We demonstrate that IFN-induced antiviral activity against influenza A virus in human cells is significantly alleviated by inhibiting ISG15 conjugation using small interfering RNAs directed against ISG15-conjugating enzymes. IFN-induced antiviral activity against influenza A virus protein synthesis was reduced 5- to 20-fold by suppressing ISG15 conjugation. The amounts of the viral proteins that were restored by these siRNA treatments were approximately 40 to 50% of the amounts produced in cells that were not pretreated with IFN. Further, we show that ISG15 conjugation inhibits influenza A virus replication 10- to 20-fold at early times after infection in human cells. These results show that ISG15 conjugation plays a substantial role in the antiviral state induced by IFN in human cells. In contrast, we show that in mouse embryo fibroblasts ISG15 conjugation not only does not affect influenza A virus replication but also does not contribute to the IFN-induced antiviral activity against influenza A virus gene expression.