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

项目概要 这项研究的长期目标是阐明 HIV-1 辅助蛋白 Vpr 的机制 改变宿主防御途径以增强 HIV-1 持续感染和发病机制。这项调查是 根据我们最近得出的五项关键发现提出的。 (1) HIV-1感染诱导I型的有效产生 通过激活 pDC 来产生干扰素 (IFN-I)，pDC 无法控制 HIV-1 感染，反而会促进 HIV-1 疾病。 (2) HIV辅助蛋白Vpr在抵消IFN-I促进的作用中发挥重要作用 HIV-1 感染。 (3) TET 甲基胞嘧啶双加氧酶被 VprBP-DDB1-CUL4-ROC1 单泛素化 (CRL4VprBP) E3 连接酶，促进 TET 与染色质结合。 (4) TET2通过序列特异性招募 转录因子（TF）并激活特定靶基因的表达，包括 干扰素 (IFN) 刺激基因 (ISG) 和病毒防御基因。 (5) Vpr与VprBP和TET相互作用 并重新编程 CRL4VprBP 连接酶以催化 TET2 的多泛素化，导致 TET2 降解和 抑制 TET2 介导的 ISG 诱导，包括三个 HIV 限制因子。 我们认为存在调节 IFN 信号传导的 IFN-JAK-STAT-TET-ISG 途径 ISG 子集的表达。 Vpr 介导的 TET 降解会破坏该途径并抵消 IFN在人体细胞中发挥抗HIV作用，但不影响IFN诱导途径，从而促进HIV-1感染 以及 IFN-I 的持续存在，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 TET 降解。目标 2 是确定 IFN-JAK-STAT-TET-ISG 途径的机制。 目标 3 将研究 Vpr 和 IFN-STAT-TET 通路如何调节 HIV-1 感染和体内持续存在， 包括 cART 期间 HIV-1 储存库的建立和反弹。目标 4 将研究 Vpr 如何 破坏 IFN-TET 通路，导致 HIV 诱导的炎症和 T 细胞耗竭/损伤。 结合两位 PI 在 HIV 病毒学和免疫学、泛素通路和 TET 介导方面的专业知识 在表观遗传控制和一系列最近的关键发现的推动下，这项研究将建立 IFN- HIV-1 靶细胞中的 JAK-STAT-TET-ISG 通路，并确定 Vpr 如何破坏该通路以导致 持续的艾滋病毒感染和艾滋病毒相关炎症。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反应的机制，识别新型病毒和宿主 开发 HIV-1“治愈”疗法的目标，并建立关于如何参与这一新途径的范例 在针对其他人类病毒的一般抗病毒机制中。 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