To eradicate the HIV macrophage reservoir

 描述(申请人提供)：HIV-1建立潜伏的蓄水池，在治疗中断后迅速释放新的传染性病毒，并导致HIV持续存在。巨噬细胞是重要的HIV储存库。它们是HIV-1感染的主要目标，几乎渗透到所有器官，可以将艾滋病毒传播到全身。不幸的是，目前的HIV-1药物在巨噬细胞中不像在T细胞中那样有效，而且它们不能跨越组织屏障，传递到组织避难所，如脑巨噬细胞。因此，新的抗HIV机制有望发展出治疗HIV感染的巨噬细胞的创新方法。Vpr是一种HIV-1辅助蛋白，也由HIV-2和SIV产生，并在这些病毒中保守。VPR增强了终末分化(未分裂)髓系细胞中的病毒复制，但其机制尚不清楚。最近，我们发现VPR可以在单核细胞来源的树突状细胞(MDDC)中增加HIV-1 Env的表达并促进病毒复制。当vpr不表达时，env通过ER相关蛋白降解(ERAD)途径迅速降解，从而抑制病毒复制；当vpr表达时，env恢复稳定，导致病毒复制增强。这些结果表明，VPR通过ERAD阻断了环境的降解。HIV-1包膜糖蛋白是通过经典的分泌途径产生的，在内质网中通过氧化折叠过程折叠成自然构象。ER蛋白的折叠过程容易出错，因此真核生物进化出ERAD质量控制途径来特异性降解错误折叠的糖蛋白。HIV-1env糖蛋白含有大量的半胱氨酸残基，必须交联成10个二硫键，因此env的折叠效率极低：80%以上的env蛋白被错误折叠并保留在内质网中降解。值得注意的是，VPR已被发现激活氧化应激途径。在这里，我们建议研究VPR如何保护Env免受ERAD途径的影响以及ERAD如何靶向Env在巨噬细胞中降解的分子机制。我们的一般假设是VPR促进了Env的氧化折叠，从而增加了巨噬细胞中Env的表达。我们将有三个特定的目的来阐明：1)氧化还原信号通路在巨噬细胞表达Env中的作用；2)VPR在巨噬细胞表达Env中的作用；3)巨噬细胞中Env降解的机制。我们相信，通过阐明这一新发现的HIV-宿主臂竞赛，我们将确定新的药物靶点，专门阻止从巨噬细胞释放具有感染性的HIV-1颗粒，从而破坏这个HIV储存库。

 DESCRIPTION (provided by applicant): HIV-1 establishes latent reservoirs, which rapidly release new infectious viruses after therapy interruption and lead to HIV persistence. Macrophages are an important HIV reservoir. They are primary targets for HIV-1 infection and infiltrated in almost all organs, which can spread HIV throughout the body. Unfortunately, current HIV-1 drugs do not work in macrophages as effectively as in T cells, and they cannot cross tissue barriers for delivery to the tissue-sanctuary sites such as brain macrophages. Thus, new anti-HIV mechanism is expected for development of innovative methods to treat HIV-infected macrophages. Vpr is a HIV-1 auxiliary protein, which is also produced by HIV-2 and SIV, and conserved in these viruses. Vpr enhances viral replication in terminally differentiated (non-dividing) myeloid cells, but this mechanism remains unclear. Recently, we uncovered that Vpr could increase HIV-1 Env expression and promote viral replication in monocyte-derived dendritic cells (MDDC). When Vpr was not expressed, Env was rapidly degraded via ER-associated protein degradation (ERAD) pathway, resulting in inhibition of viral replication; when Vpr was expressed, the Env stability was restored, resulting in enhancement of viral replication. These results demonstrate that Vpr blocks Env degradation via ERAD. HIV-1 Env glycoproteins are produced through the classical secretory pathway, which are folded into natural conformation in the ER via the oxidative folding process. The ER protein folding process is error-prone, so eukaryotes have evolved the ERAD quality control pathway to specifically degrade misfolded glycoproteins. HIV-1 Env glycoproteins have a large number of cysteine residues that must be cross-linked into 10 disulfide bonds, so the Env folding efficiency is extremely lower: over 80% Env proteins are misfolded and retained in the ER for degradation. Notably, Vpr has been found to activate the oxidative stress pathway. Here, we propose to study the molecular mechanisms of how Vpr protects Env from the ERAD pathway and how ERAD targets Env for degradation in macrophages. Our general hypothesis is that Vpr promotes Env oxidative folding to increase Env expression in macrophages. We will have three specific aims to elucidate: 1) The role of redox signaling pathway in Env expression in macrophages; 2) The role of Vpr in Env expression in macrophages; 3) The mechanism of Env degradation in macrophages. We believe that by elucidating this newly discovered HIV-host arm race, we will identify new drug targets to specifically block the release of infectious HIV-1 particles from macrophages, resulting in disruption of this HIV reservoir.