The Semen Enhancer of HIV Infection as a Novel Microbicide Target

描述（由申请人提供）：人类精液中含有阳离子淀粉样蛋白原纤维，被称为“病毒感染精液增强剂”（SEVI），它强烈增强HIV-1感染，可能在病毒传播中起重要作用。我们的初步数据显示淀粉样蛋白结合分子与SEVI结合，并阻断精液介导的HIV-1感染增强。这表明(i) SEVI负责精液介导的HIV感染增强，（ii） SEVI代表了一种新的杀微生物剂靶点。因此，我们建议探索一种新的、创新的方法来开发HIV-1杀菌剂，使用选择性靶向SEVI的药物。这种高风险/高回报的方法与针对病毒本身的传统杀微生物策略根本不同，预计将与直接抗病毒方法高度互补。事实上，我们的长期目标是将sevi靶向药物与传统的杀微生物剂联合使用，以达到最佳的抗病毒效果。在R21期，我们将测试新的淀粉样蛋白结合小分子是否抑制精液介导的HIV感染增强。这种方法的可行性已经建立在两个淀粉样蛋白结合的小分子上，它们含有“屏蔽”低聚乙二醇（EG）片段：BTA-EG4和-EG6。这些药物有效地抑制了SEVI和精液介导的HIV感染增强。在Aim 1中，我们将生成并测试这些和其他淀粉样蛋白结合分子的新衍生物，包括预计具有更高SEVI结合亲和力的低价分子。然后，我们将使用一组R5病毒株（包括不同的分支和传播株）来测试它们抑制SEVI和精液介导的HIV感染增强的能力。在Aim 2中，我们将研究新型淀粉样蛋白结合小分子与女性生殖道细胞之间的相互作用。我们将评估我们的化合物是否对人宫颈阴道上皮细胞（HCEC）有毒，我们将测试它们是否抑制sevi增强的HIV-1与HCEC的结合和/或暴露于HIV-1病毒粒子的HCEC对PBMC的sevi增强的反式感染。只有在实现了明确定义的里程碑后，才会进行R33阶段。在目标3中，我们将使用构效关系（SAR）数据来改进我们的化学成分。我们还将测试我们的铅分子是否对HIV-1感染的宫颈外植体模型有效，以及它们是否对其他候选杀微生物剂在精液存在下抑制HIV-1感染的能力具有协同或加性作用。在最后的目的，我们将评估最有希望的候选分子的毒性和炎症作用，使用有益的乳酸杆菌菌株和宫颈外植体。R33阶段将在兔阴道刺激（RVI）模型中评估最有希望的化合物的安全性和耐受性。这些研究的总体目标是仔细确定靶向SEVI的小分子是否具有作为新型杀微生物剂的潜在效用。

DESCRIPTION (provided by applicant): Human semen contains cationic amyloid fibrils, termed the "Semen Enhancer of Virus Infection" (SEVI), which strongly enhance HIV-1 infection and may play an important role in viral transmission. Our preliminary data show that amyloid-binding molecules bind to SEVI, and block semen-mediated enhancement of HIV-1 infection. This suggests that (i) SEVI is responsible for semen-mediated enhancement of HIV infection and (ii) SEVI represents a novel microbicide target. We therefore propose to explore a novel, innovative approach to HIV-1 microbicide development, using agents that selectively target SEVI. This high-risk/high-reward approach is fundamentally different from traditional microbicidal strategies that target the virus itself, and is expected to be highly complementary with direct antiviral approaches. Indeed, our long-term goal is to use SEVI-targeting agents in combination with traditional microbicides, to achieve optimal antiviral effectiveness. In the R21 phase, we will test whether novel amyloid-binding small molecules inhibit semen-mediated enhancement of HIV infection. The feasibility of this approach has been established using two amyloid-binding small molecules which contain "shielding" oligo-ethylene glycol (EG) moieties: BTA-EG4 and -EG6. These agents efficiently inhibit SEVI- and semen-mediated enhancement of HIV infection. In Aim 1, we will generate and test novel derivatives of these and other amyloid-binding molecules, including oligovalent molecules that are expected to possess increased SEVI binding affinity. We will then test their ability to inhibit SEVI- and semen- mediated enhancement of HIV infection using a panel of R5 virus strains (including different clades and transmitted strains). In Aim 2, we will examine the interaction between novel amyloid-binding small molecules and cells from the female reproductive tract. We will evaluate whether our compounds are toxic to human cervicovaginal epithelial cells (HCEC), and we will test whether they inhibit SEVI-enhanced binding of HIV-1 to HCEC and/or SEVI-enhanced trans-infection of PBMC by HCEC exposed to HIV-1 virions. The R33 phase will be undertaken only if well-defined milestones are achieved. In Aim 3, we will use structure-activity relationship (SAR) data to refine our chemical compositions. We will also test whether our lead molecules have efficacy in a cervical explant model for HIV-1 infection, and whether they have a synergistic or additive effect on the ability of other candidate microbicides to inhibit HIV-1 infection in the presence of semen. In the final Aim, we will assess the toxicity and inflammatory effects of the most promising candidate molecules, using beneficial Lactobacillus strains and cervical explants. The R33 phase will culminate with an evaluation of the safety and tolerability of the most promising compound in the rabbit vaginal irritation (RVI) model. The overall goal of these studies is to carefully determine whether small molecules that target SEVI have potential utility as a novel class of microbicides. PUBLIC HEALTH RELEVANCE: New approaches to prevent the transmission of human immunodeficiency virus type-1 (HIV-1) are urgently needed. This application seeks to develop a new class of microbicidal agents that are targeted not to the virus itself, but to a host protein found in semen that strongly enhances HIV-1 infection. This high risk, high reward approach is fundamentally different from traditional microbicidal strategies that target the virus, and is expected to be highly complementary with direct antiviral approaches.