Complex Interplay between HIV-1 Capsid and MX2-Independent Alpha Interferon-Induced Antiviral Factors.
Complex Interplay between HIV-1 Capsid and MX2-Independent Alpha Interferon-Induced Antiviral Factors.
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DOI：
10.1128/jvi.00458-16
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发表时间：
2016-08-15
影响因子：
5.4
通讯作者：
Schaller T
中科院分区：
文献类型：
--
作者：
Bulli L;Apolonia L;Kutzner J;Pollpeter D;Goujon C;Herold N;Schwarz SM;Giernat Y;Keppler OT;Malim MH;Schaller T
包括干扰素-α在内的I型干扰素可上调干扰素刺激基因的表达，有效抑制人类免疫缺陷病毒1型在T细胞、单核细胞来源的巨噬细胞和树突状细胞中的感染性。最近，我们和其他人发现ISG粘病毒耐药2(MX2)是HIV-1核进入的抑制因子。然而，在核进口的上游还存在其他的抗病毒阻滞剂，但抑制感染的ISGs，例如在逆转录之前(或期间)，仍有待定义。我们在这里展示了HIV-1CA突变N74D和A105T，这两个突变都可以逃避MX2和切割和多聚腺苷化特异因子6的截短版本的抑制，以及亲环素A(CypA)结合环突变P90A，都增加了对干扰素-α介导的抑制的敏感性。利用簇状规则间隔短回文重复序列(CRISPR)/CAS9技术，我们证明了这些突变体在THP-1细胞中的干扰素-α超敏反应不受MX2或CPSF6的影响。正如预期的那样，CypA缺失对P90A突变体的行为没有额外的影响，但适度增加了野生型病毒对干扰素-α的敏感性。有趣的是，野生型或P90A病毒可被环孢菌素(Cs)或其非免疫抑制类似物SDZ-NIM811处理，使野生型或P90A病毒的感染性从干扰素-α诱导的阻断中解脱出来，这表明Cs敏感的宿主细胞亲环素而不是CypA参与了干扰素-α诱导的阻断的活性。我们认为，细胞与传入的HIV-1衣壳的相互作用有助于保护病毒免受抗病毒效应器机制的识别。因此，CA蛋白是抑制或促进HIV-1感染的细胞编码功能之间动态相互作用的支点。重要性HIV-1是艾滋病的病原体。在急性HIV-1感染期间，会产生许多促炎细胞因子，包括I型干扰素(IFN)。干扰素可以通过诱导一组抗病毒基因的表达来限制HIV-1的复制，这些基因在HIV-1生命周期的多个步骤中抑制HIV-1，包括进入后的反转录和核进口步骤。这是在培养细胞系统中观察到的，以及在HIV-1感染患者的临床试验中观察到的。细胞抗病毒因子的特性、它们的病毒靶点和基础机制在很大程度上尚不清楚。我们在这里表明，HIV-1衣壳蛋白在保护病毒免受干扰素诱导的抑制剂的影响方面发挥着核心作用，干扰素诱导的抑制剂阻止了进入后感染的早期步骤。我们进一步表明，宿主细胞亲环素在调节这些过程中发挥着重要作用，从而突出了抗病毒效应机制和病毒存活之间的复杂相互作用。
Type I interferons (IFNs), including IFN-α, upregulate an array of IFN-stimulated genes (ISGs) and potently suppress Human immunodeficiency virus type 1 (HIV-1) infectivity in CD4+ T cells, monocyte-derived macrophages, and dendritic cells. Recently, we and others identified ISG myxovirus resistance 2 (MX2) as an inhibitor of HIV-1 nuclear entry. However, additional antiviral blocks exist upstream of nuclear import, but the ISGs that suppress infection, e.g., prior to (or during) reverse transcription, remain to be defined. We show here that the HIV-1 CA mutations N74D and A105T, both of which allow escape from inhibition by MX2 and the truncated version of cleavage and polyadenylation specific factor 6 (CPSF6), as well as the cyclophilin A (CypA)-binding loop mutation P90A, all increase sensitivity to IFN-α-mediated inhibition. Using clustered regularly interspaced short palindromic repeat (CRISPR)/Cas9 technology, we demonstrate that the IFN-α hypersensitivity of these mutants in THP-1 cells is independent of MX2 or CPSF6. As expected, CypA depletion had no additional effect on the behavior of the P90A mutant but modestly increased the IFN-α sensitivity of wild-type virus. Interestingly, the infectivity of wild-type or P90A virus could be rescued from the MX2-independent IFN-α-induced blocks in THP-1 cells by treatment with cyclosporine (Cs) or its nonimmunosuppressive analogue SDZ-NIM811, indicating that Cs-sensitive host cell cyclophilins other than CypA contribute to the activity of IFN-α-induced blocks. We propose that cellular interactions with incoming HIV-1 capsids help shield the virus from recognition by antiviral effector mechanisms. Thus, the CA protein is a fulcrum for the dynamic interplay between cell-encoded functions that inhibit or promote HIV-1 infection. IMPORTANCE HIV-1 is the causative agent of AIDS. During acute HIV-1 infection, numerous proinflammatory cytokines are produced, including type I interferons (IFNs). IFNs can limit HIV-1 replication by inducing the expression of a set of antiviral genes that inhibit HIV-1 at multiple steps in its life cycle, including the postentry steps of reverse transcription and nuclear import. This is observed in cultured cell systems, as well as in clinical trials in HIV-1-infected patients. The identities of the cellular antiviral factors, their viral targets, and the underpinning mechanisms are largely unknown. We show here that the HIV-1 Capsid protein plays a central role in protecting the virus from IFN-induced inhibitors that block early postentry steps of infection. We further show that host cell cyclophilins play an important role in regulating these processes, thus highlighting the complex interplay between antiviral effector mechanisms and viral survival.