To eradicate the HIV macrophage reservoir

 描述（由申请方提供）：HIV-1建立潜伏性储库，在治疗中断后迅速释放新的感染性病毒，导致HIV持续存在。巨噬细胞是重要的HIV宿主。它们是HIV-1感染的主要目标，并渗透到几乎所有器官，可将HIV传播到全身。不幸的是，目前的HIV-1药物在巨噬细胞中的作用不如在T细胞中有效，并且它们不能穿过组织屏障递送到组织保护区，如脑巨噬细胞。因此，新的抗HIV机制有望用于开发治疗HIV感染的巨噬细胞的创新方法。Vpr是HIV-1辅助蛋白，也由HIV-2和SIV产生，并且在这些病毒中保守。Vpr增强病毒在终末分化（非分裂）髓样细胞中的复制，但其机制尚不清楚。最近，我们发现Vpr可以增加HIV-1 Env在单核细胞来源的树突状细胞（MDDC）中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）途径快速降解，导致病毒复制抑制;当Vpr表达时，Env稳定性恢复，导致病毒复制增强。这些结果表明Vpr通过ERAD阻断Env降解。HIV-1 Env糖蛋白通过经典的分泌途径产生，其在ER中通过氧化折叠过程折叠成天然构象。ER蛋白的折叠过程是容易出错的，因此真核生物已经进化出ERAD质量控制途径来特异性地降解错误折叠的糖蛋白。HIV-1 Env糖蛋白有大量的半胱氨酸残基，必须交联成10个二硫键，因此Env折叠效率极低：超过80%的Env蛋白错误折叠并保留在ER中进行降解。值得注意的是，已发现Vpr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Env氧化折叠以增加巨噬细胞中的Env表达。本论文的主要研究内容包括三个方面：1）氧化还原信号通路在巨噬细胞Env表达中的作用; 2）Vpr在巨噬细胞Env表达中的作用; 3）Env在巨噬细胞中的降解机制。我们相信，通过阐明这一新发现的HIV宿主军备竞赛，我们将确定新的药物靶点，以特异性地阻断巨噬细胞释放感染性HIV-1颗粒，从而破坏这种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.