HIV-1 Resistance to Chemokine Receptor Antagonists

描述（由申请方提供）：HIV-1进入靶细胞涉及病毒包膜蛋白与特异性细胞表面受体的相互作用，最终导致病毒和宿主细胞膜融合。这个多步骤的过程为药物开发提供了许多潜在的目标。在当前的资助期间，在理解病毒动力学、适应性后果和ENF抗性的临床意义方面取得了重大进展。我们现在建议将这些研究扩展到接受CCR 5抑制剂治疗的患者的HIV-1分离株。由于它们在病毒进入中的关键作用，趋化因子共受体是药物开发的有吸引力的靶点。几种小分子CCR 5抑制剂已在体外和HIV-1感染受试者中显示出有效的抗HIV-1活性，其中两种（马拉韦罗和vicriviroc）处于临床开发的晚期阶段。通过体外传代选择的马拉韦罗和维昔韦罗耐药HIV-1分离株的研究表明，这些耐药病毒保留其R5表型，并继续依赖CCR 5进入[Pugach]。然而，鲜为人知的是，通过暴露于这些抑制剂在体内选择的HIV-1分离株的属性。此外，关于在药物压力下感染双嗜性或混合R5和X4病毒的人的病毒准种变化的信息很少。因此，我们建议使用从vicriviro 2期研究中病毒学失败的受试者中获得的样本，分析在存在CCR 5抑制剂vicriviroc的情况下病毒对复制的适应，AIDS临床试验组方案A5211。提出了以下四个具体目标：1）鉴定来自CCR 5抑制剂敏感性降低的vicriviroc治疗受试者的HIV-1包膜; 2）鉴定体内与vicriviroc耐药性相关的HIV-1包膜的基因型变化; 3）确定vicriviroc耐药性对病毒适应度的影响; 4）检查vicriviroc耐药性HIV-1的进入动力学。对于后一个目标，我们将使用大规模并行测序的新技术，使用微型皮升反应器。这些实验的结果将是高度相关的了解机制和耐药性的后果，这类新的HIV- 1治疗，并将提供数据，是必要的，他们在治疗HIV-1感染者的适当使用。

DESCRIPTION (provided by applicant): Entry of HIV-1 into target cells involves the interaction of viral envelope proteins with specific cell surface receptors, leading ultimately to fusion of viral and host cell membranes. This multi-step process offers a number of potential targets for drug development. During the current funding period, significant progress was made towards understanding the viral dynamics, fitness consequences and clinical significance of ENF resistance. We now propose to extend these studies to HIV-1 isolates from patients treated with CCR5 inhibitors. Because of their critical role in virus entry, the chemokine co-receptors are attractive targets for drug development. Several small-molecule CCR5 inhibitors have demonstrated potent anti-HIV-1 activity in vitro and in HIV-1-infected subjects, two of which (maraviroc and vicriviroc) are in advanced stages of clinical development. Studies of maraviroc- and vicriviroc-resistant HIV-1 isolates selected by in vitro passage show that these resistant viruses retain their R5 phenotype and continue to rely on CCR5 for entry [Pugach]. However, little is known about the properties of HIV-1 isolates selected by exposure to these inhibitors in vivo. In addition, scant information is available on shifts in the viral quasispecies in persons infected with dual-tropic or mixed R5 and X4 viruses under drug pressure. We therefore propose to analyze viral adaptation to replication in the presence of the CCR5 inhibitor vicriviroc using samples obtained from subjects with virologic failure in the phase 2 study of vicriviroc, AIDS Clinical Trials Group protocol A5211. The following four specific aims are proposed: 1) To identify HIV-1 envelopes from vicriviroc-treated subjects with reduced CCR5 inhibitor susceptibility; 2) to identify genotypic changes in HIV-1 env associated with vicriviroc resistance in vivo; 3) to determine the effect of vicriviroc resistance on viral fitness; 4) to examine the entry kinetics of vicriviroc-resistant HIV-1. For this latter aim we will use the novel technology of massively parallel sequencing using microfabricated picoliter reactors. Results of these experiments will be highly relevant to understanding the mechanisms and consequences of resistance to this novel class of HIV- 1 therapeutics and will provide data that are essential to their proper use in the treatment of HIV-1-infected individuals.