HIV-1 Vpr disrupts the IFN-TET-ISG pathway to promote HIV-1 infection and persistence

项目摘要 本研究的长期目标是阐明HIV-1辅助蛋白Vpr 改变宿主防御途径，增强HIV-1的持续感染和致病性。这项调查是 基于我们最近的五个关键发现。(1)HIV-1感染诱导I型 干扰素（IFN-I）通过激活pDC，这不能控制HIV-1感染，而是有助于HIV-1 疾病(2)HIV辅助蛋白Vpr在对抗IFN-Ⅰ促进HIV-1表达的作用中起重要作用。 HIV-1感染。(3)泰特甲基胞嘧啶双加氧酶被VprBP-DDB 1-CUL 4-ROC 1单泛素化 （CRL 4 VprBP）E3连接酶，其促进泰特与染色质结合。(4)TET 2被序列特异性的 转录因子（TF）的作用，并激活特定的靶基因的表达，包括一个子集， 干扰素（IFN）刺激基因（ISG）和病毒防御基因。(5)Vpr与VprBP和泰特相互作用 并重编程CRL 4VprBP连接酶以催化TET 2的多泛素化，导致TET 2降解， 抑制TET 2介导的ISG诱导，包括三种HIV限制因子。 我们认为存在一个IFN-JAK-STAT-TET-ISG通路调节IFN信号传导， ISG子集的表达。Vpr介导的泰特降解破坏了这一途径， IFN在人体细胞中的抗HIV作用，但不是IFN诱导途径，从而促进HIV-1感染 以及在IFN-1存在下的持久性，这有助于HIV诱导的炎症和发病机制。 我们提出了四个具体目标来检验这一假设。目标1将确定Vpr的功能和机制- 介导的泰特降解。目的2：研究IFN-JAK-STAT-TET-ISG信号通路的作用机制。 目的3将研究Vpr和IFN-STAT-泰特通路如何调节体内HIV-1感染和持续性， 包括cART期间HIV-1储库的建立和反弹。目标4将研究Vpr如何 干扰IFN-TET通路，导致HIV诱导的炎症和T细胞耗竭/损伤。 结合两名PI在HIV病毒学和免疫学方面的专业知识，泛素途径和TET介导 表观遗传控制和最近的一系列关键发现的动机，这项调查将建立干扰素- JAK-STAT-TET-ISG途径，并确定Vpr如何破坏该途径，导致HIV-1靶细胞中的 持续的HIV感染和HIV相关炎症。这项调查还将深入了解DNA 去/甲基化作为动态基因调控和免疫应答的机制，鉴定新的病毒和宿主 开发HIV-1“治愈”治疗的目标，并建立一个关于这种新途径如何参与的范例 对其他人类病毒的一般抗病毒机制。 1

PROJECT SUMMARY The long-term goal of this investigation is to elucidate the mechanisms by which HIV-1 accessory protein Vpr alters host defense pathway to enhance HIV-1 persistent infection and pathogenesis. This investigation is proposed based on five key findings we made recently. (1) HIV-1 infection induces efficient production of type I interferons (IFN-I) by activating pDC, which fails to control HIV-1 infection but rather contributes to HIV-1 diseases. (2) HIV accessory protein Vpr plays an important role to counteract the effect of IFN-I to promote HIV-1 infection. (3) TET methylcytosine dioxygenases are monoubiquitylated by the VprBP-DDB1-CUL4-ROC1 (CRL4VprBP) E3 ligase which promotes TET binding to chromatin. (4) TET2 is recruited by sequence-specific transcription factors (TFs) to and activates the expression of specific target genes, including a subset of interferon (IFN)-stimulated genes (ISGs) and viral-defense genes. (5) Vpr interacts with both VprBP and TET and reprograms CRL4VprBP ligase to catalyze polyubiquitylation of TET2, resulting in TET2 degradation and inhibition of TET2-mediated induction of ISGs, including three HIV restriction factors. We propose that there exists an IFN-JAK-STAT-TET-ISG pathway that modulates IFN signaling and the expression of a subset of ISGs. The Vpr-mediated degradation of TET disrupts this pathway and counteracts the anti-HIV effect of IFN in human cells but not the IFN induction pathway, thereby promoting HIV-1 infection and persistence in the presence of IFN-I, which contributes to HIV-induced inflammation and pathogenesis. We propose four specific aims to test this hypothesis. Aim 1 will determine the function and mechanism Vpr- mediated TET degradation. Aim 2 is to determine the mechanism of the IFN-JAK-STAT-TET-ISG pathway. Aim 3 will study how Vpr and the IFN-STAT-TET pathway modulate HIV-1 infection and persistence in vivo, including the establishment and rebound of HIV-1 reservoir during cART. Aim 4 will investigate how Vpr disrupts the IFN-TET pathway to contribute to HIV-induced inflammation and T cell depletion/impairment. Combining the expertise of the two PIs in HIV virology and immunology, ubiquitin pathway and TET-mediated epigenetic control and motivated by a series of recent key findings, this investigation will establish the IFN- JAK-STAT-TET-ISG pathway in HIV-1 target cells and determine how Vpr disrupts this pathway to lead to persistent HIV infection and the HIV-associated inflammation. This investigation will also gain insights into DNA de/methylation as a mechanism in dynamic gene regulation and immune response, identify novel viral and host targets for developing HIV-1 “cure” treatments, and establish a paradigm on how this novel pathway is involved in the general anti-viral mechanism against other human viruses. 1