Novel Mechanisms of Disarming Anti-HIV Host Defenses by Methamphetamine

 描述(由申请人提供)：甲基苯丙胺(Meth)是艾滋病毒流行病学中的一个主要风险因素，它促进了增加接触病毒和减少坚持治疗的行为。但除了对行为的这些影响外，Meth似乎还增加了艾滋病毒的复制，并加速了向艾滋病的进展。我们假设这种滥用药物可以通过使宿主细胞内防御的特定成分失效而起到有效促进艾滋病毒感染和传播的作用。这一假说是基于我们最近的发现，即Meth显著降低了抗HIV的细胞蛋白的表达，特别是介导miRNA加工和功能的RNA诱导沉默复合体(RISC)成分ArgAerte-1(Ago1)和P体成分APOBEC3G。此外，Meth还减少了调节宿主分子PCAF和Pur-a的CD4+T细胞中的miRNA物种，并已知其可限制HIV的复制。据我们所知，以前还没有关于甲硫氨酸对限制艾滋病毒复制和传播的细胞内介质的影响的报道。我们将在下面概述的一系列目标中追求这一新的范例，即Meth解除特定的细胞内防御并增强艾滋病毒。具体的创新点包括：(1)探索Meth对抗HIV的RISC组件Ago1的独特作用；(2)了解Meth如何调节miRNAs，以及细胞内的HIV依赖因素，重点是PCAF和Pur-a；(3)表征Meth对树突状细胞和巨噬细胞中肌动蛋白细胞骨架的影响，从而使HIV不是在溶酶体中降解，而是被转运到外体，并更容易在免疫突触传递到CD4+T细胞。在我们新的初步数据的基础上，我们将在实验上追求以下具体目标：(1)表征Meth降低AGO-1表达和功能的分子机制，并与HIV-1合作改变P-小体的结构完整性。(2)进一步表征受Meth差异调控的细胞miRNA物种的变化，以及这些变化如何增强HIV-1的复制。(3)表征Meth对树突状细胞肌动蛋白细胞骨架和片层脂蛋白形成的影响，重点是RISC及其相关miRNA向P小体的转运，以及HIV向外体途径的分流，而不是溶酶体的降解。通过进一步产生这一新知识，我们希望为限制Meth使用者感染艾滋病毒的创新战略提供基础，Meth是艾滋病的一个突出风险因素。

 DESCRIPTION (provided by applicant): Methamphetamine (Meth) is a major risk factor in the epidemiology of HIV, promoting behavior that both increases exposure to virus and reduces adherence to treatment. But beyond such effects on behavior, Meth appears to augment HIV replication and accelerate progression to AIDS. We hypothesize that this drug of abuse can act as a potent facilitator of HIV infection and transmission by disabling specific components of host intracellular defense. This hypothesis is based on our recent findings that Meth markedly decreased expression of cellular proteins that oppose HIV, specifically the RNA-induced silencing complex (RISC) component, Argonaute-1 (AGO1), which mediates miRNA processing and function, and the P-body constituent, APOBEC3G. In addition, Meth reduced miRNA species in CD4+ T-cells that regulate host molecules PCAF and Pur-a, and are known to restrict HIV replication. To our knowledge, there are no previous reports of these effects of Meth on intracellular mediators that limit HIV replication and transmission. We will pursue this new paradigm of Meth disarming specific intracellular defenses and enhancing HIV in a series of aims outlined below. Specific points of innovation include: (1) exploring unique effects of Meth on the RISC component AGO1 which opposes HIV; (2) understanding how Meth can regulate miRNAs, and cellular HIV dependency factors, focusing on PCAF and Pur-a; (3) characterizing effects of Meth on the actin cytoskeleton in dendritic cells and macrophages, so that instead of virus degradation in lysosomes, HIV is trafficked to exosomes and more readily transmitted at the immune synapse to CD4+ T-cells. Building on our novel preliminary data, we will pursue experimentally the following specific aims: (1) Characterize the molecular mechanisms whereby Meth can reduce AGO-1 expression and function, and cooperate with HIV-1 in altering the structural integrity of P-bodies. (2) Further characterize changes in cellular miRNA species that are differentially modulated by Meth, and how these changes augment HIV-1 replication. (3) Characterize effects of Meth on the actin cytoskeleton and lamellipoda formation in dendritic cells, focusing on trafficking of the RISC and associated miRNA to P-bodies, and shunting of HIV to an exosome pathway rather than to lysosomal degradation. By further generating this new knowledge, we hope to provide the foundation for innovative strategies to limit HIV infection in users of Meth, a prominent risk factor for AIDS.