Development of Lead Inhibitors of HIV Vif Binding to Antiretroviral A3G Through Medicinal Chemistry

项目摘要 HIV宿主限制因子APOBEC3G(A3G)可通过诱导灾难性的 病毒基因组中的突变。HIV Vif蛋白通过与A3G结合并引导 它与蛋白酶体的降解途径有关。拟议的SBIR第一阶段的意义 研究表明，VIF仍是一个新的抗病毒靶点，其临床潜力尚未充分发挥 探索过了。尽管有很多关于VIF的学术研究，但只有有限的努力去确定 Vif的小分子拮抗剂。OyaGen，Inc.是目前唯一寻求 以有意义的方式与VIF特异性相互作用的化学支架的鉴定 药物开发。先前的抗VIF药物发现努力的一个固有限制是使用 可能由多种作用机制引起的主要药物筛查。我们 设计了一种活细胞猝灭FRET(FqRET)报告实验，使选择膜- 利用Vif突变体研究Vif和A3G之间蛋白质-蛋白质相互作用的通透性拮抗剂 这保留了与A3G的野生型结合，但不再与Elongin C结合，不再促进 A3G降级。从110K类药物化合物小分子文库的筛选中，我们 确定了165个优先HIS以供进一步分析。尽管有一些化合物是剂量依赖的 A3G的Vif结合的拮抗剂，一种化合物，以下称为C5，是无细胞毒性的 并表现出剂量依赖性：i)抑制Vif依赖的A3G降解，ii)抑制 伪型HIV复制和iii)促进A3G在病毒粒子中的掺入增加。这里 我们提出了一条创新的药物发现关键路径来优化一种新型的抗HIV先导化合物 来自C5的第二阶段SBIR药代动力学分析，体内疗效测试，以及 支持IND的研究。第一阶段SBIR的目标将集中在结构-活性关系(SAR) 用于抗HIV化合物Hit-to-Lead优化的C5支架的药物化学 抗病毒活性的机制是由于其作为Vif拮抗剂的功能，保护A3G免受 依赖于Vif的降解。

Project Summary The HIV host restriction factor APOBEC3G (A3G) can inhibit HIV by inducing catastrophic mutations in the viral genome. The HIV Vif protein protects HIV by binding to A3G and directing it to the proteasomal degradation pathway. The significance of the proposed SBIR phase I research is that Vif remains a new antiviral target whose clinical potential has yet to be fully explored. Despite much academic research on Vif, only a limited effort has gone toward identifying small molecule antagonists of Vif. OyaGen, Inc. is the only commercial entity currently pursuing the identification of chemical scaffolds that specifically interact with Vif in meaningful ways for drug development. An inherent limitation of prior anti-Vif drug discovery efforts has been the use of primary drug screens in which ‘hits’ may be due to more than one mechanisms of action. We designed a live cell quenched FRET (FqRET) reporter assay that enables selection of membrane- permeable antagonists of protein-protein interactions between Vif and A3G using a Vif mutant that retains wild type binding to A3G but no longer binds to Elongin C and no longer facilitates A3G degradation. From a screen of a 110K small molecule library of drug-like compounds we identified 165 prioritized his for further analysis. Although a few compounds were dose-dependent antagonists of Vif binding of A3G, one compound, hereafter referred to as C5, was non-cytotoxic and displayed dose-dependent: i) inhibition of Vif-dependent A3G degradation, ii) inhibition of pseudotyped HIV replication and iii) promoted an increased incorporation of A3G in virions. Here we propose an innovative drug discovery critical path to optimize a novel anti-HIV lead compound from C5 in anticipation of phase II SBIR pharmacokinetic analysis, in vivo efficacy testing, and IND-enabling studies. The Phase I SBIR Aims will focus on structure-activity relationship (SAR) medicinal chemistry of the C5 scaffold for hit-to-lead optimization of anti-HIV compound whose antiviral activity is mechanistically due to its function as a Vif antagonist that protects A3G from Vif-dependent degradation.