Both Cyclophilin Inhibitors and Direct-Acting Antivirals Prevent PKR Activation in HCV-Infected Cells.
Both Cyclophilin Inhibitors and Direct-Acting Antivirals Prevent PKR Activation in HCV-Infected Cells.
复制标题
DOI：
10.2174/1874357901408010001
复制
发表时间：
2014
期刊：
影响因子：
--
通讯作者：
Gallay P
中科院分区：
文献类型：
--
作者：
Bobardt M;Chatterji U;Lim P;Gawlik K;Gallay P
我们和其他人证明 NS5A 和宿主因子 CypA 之间的接触对于 HCV 复制至关重要。 CypI 通过破坏 NS5A-CypA 复合物，在体外和患者体内阻断 HCV 复制。由于 NS5A 还与 PKR（IFN 应答的核心成分）结合，因此我们研究了 CypA、NS5A 和 PKR 在针对 HCV 的 IFN 应答中之间关系的可能性。分析用 CypI、DAA 或 IFN 处理的 HCV 感染细胞的先天反应各种成分的表达和激活。我们发现 CypI（环孢素 A、阿拉孢韦、NIM811 和 sanglifehrins）可显着阻止 HCV 感染细胞中 IFN 诱导的 PKR 的激活/磷酸化，但不能阻止其表达。 CypI 对先天反应的其他成分（例如 eiF2、NF-kB、IRF3、IRF9、STAT1 和 STAT2）的表达或磷酸化没有影响，表明对 PKR 有特定影响。在没有 HCV 的情况下，没有观察到 IFN 诱导的 PKR 的显着激活。重要的是，我们发现几类 DAA（例如 NS3/4A 蛋白酶、NS5B 聚合酶和 NS5A 抑制剂）也能阻止 PKR 激活。此外，我们发现 CypI 或 DAA 无法阻止 dsRNA 模拟物 Poly I:C 激活 PKR。我们的研究结果表明，CypI 对 PKR 激活没有独特的作用，而是任何抗 HCV 抑制剂对 HCV 复制的抑制，消除了 IFN 诱导的 PKR 激活。此外，他们认为 dsRNA 中间体的积累允许 HCV 利用 PKR 的激活来抵消 IFN 反应。
We and others demonstrated that the contact between NS5A and the host factor CypA is critical for HCV replication. CypI, by disrupting NS5A-CypA complexes, block HCV replication both in vitro and in patients. Since NS5A also binds to PKR, a central component of the IFN response, we investigated the possibility of a relationship between CypA, NS5A and PKR in the IFN response to HCV. HCV-infected cells treated with CypI, DAAs or IFN were analyzed for the expression and activation of various components of the innate response. We found that CypI (cyclosporine A, alisporivir, NIM811 and sanglifehrins), drastically prevented the activation/phosphorylation, but not the expression of IFN-induced PKR in HCV-infected cells. CypI had no effect on the expression or phosphorylation of other components of the innate response such as eiF2, NF-kB, IRF3, IRF9, STAT1 and STAT2, suggesting a specific effect on PKR. No significant activation of IFN-induced PKR was observed in the absence of HCV. Importantly, we found that several classes of DAAs such as NS3/4A protease, NS5B polymerase and NS5A inhibitors also prevented PKR activation. Furthermore, we found that PKR activation by the dsRNA mimic poly I:C cannot be prevented by CypI or DAAs. Our findings suggest that CypI do not have a unique effect on PKR activation, but rather the suppression of HCV replication by any anti-HCV inhibitor, abrogates PKR activation induced by IFN. Moreover, they suggest that the accumulation of dsRNA intermediates allows HCV to exploit the activation of PKR to counteract the IFN response.