Ultrapotent Inhibitors of Wild-type and Multi-drug Resistant HIV

描述：核苷类逆转录酶抑制剂（NRTIs）是用于治疗hiv感染患者的高效抗逆转录病毒疗法（HAART）的关键成分。所有fda批准的抗HIV nrti缺乏3'-OH，因此通过立即链终止抑制HIV RT的DNA聚合。与天然dNTP底物相比，缺乏3'-OH也会降低NRTI对RT的结合亲和力，并减少细胞内向活性NRTI三磷酸盐的转化，从而赋予这些NRTI有害的特性。我们在第一个资助周期中报道，4'-乙基-2-氟-2'-脱氧腺苷（EFdA）是一种核苷类似物，保留了3'-OH部分，并表现出卓越的抗病毒特性（在PBMCs中EC50 = 50 pM）和显着的选择性指数（bbb20万）。EFdA的效力和选择性指数比目前所有批准的抗hiv药物都要有利。尽管存在3'-OH，但由于RT难以在具有3'-末端EFdA-MP的引物上易位，因此纳入的efda -单磷酸主要作为直接链终止物，这是一种独特的作用机制。因此，EFdA-TP是易位缺陷RT抑制剂（TDRTI）。此外，EFdA也被证明能有效抑制临床重要的nrti耐药HIV毒株，并显示出对替诺福韦耐药K65R HIV的超敏感。值得注意的是，在我们对siv感染的猕猴的研究中，经EFdA治疗抑制病毒载量的动物携带M184V突变，这表明EFdA可以有效抑制M184V。我们还表明，EFdA对HIV耐药性具有非常高的屏障，许多EFdA耐药的HIV毒株的复制能力降低。最近，我们已经证明EFdA与Rilpivirine的组合显示出协同效应，这将有助于设计新的治疗方案。我们将以第一个融资周期的工作为基础，了解EFdA在RT和细胞水平上的效力、EFdA耐药性的发展以及EFdA与目前批准的抗hiv药物的联合。我们还将使用生化和结构方法来表征RT水平上EFdA的抑制机制，脱氧胞苷激酶（dCK）激活EFdA和腺苷脱氨酶（ADA）脱氨。这项研究将提供的信息将指导新的nrti和EFdA与其他已批准的抗HIV药物联合治疗的设计，这可能会导致HIV感染治疗的突破。

DESCRIPTION: Nucleoside reverse transcriptase inhibitors (NRTIs) are key components of Highly Active Antiretroviral Therapies (HAART) for the treatment of HIV-infected patients. All FDA-approved anti-HIV NRTIs lack a 3'-OH, and therefore inhibit DNA polymerization by HIV RT through immediate chain termination. The absence of a 3'-OH also imparts detrimental properties to these NRTIs by reducing their binding affinity for RT compared to the natural dNTP substrates and reducing intracellular conversion to active NRTI triphosphates. We have reported during the first funding cycle that 4'-ethynyl-2-fluoro-2'-deoxyadenosine (EFdA) is a nucleoside analog that retains the 3'-OH moiety and demonstrates exceptional antiviral properties (EC50 = 50 pM in PBMCs) and a remarkable selectivity index (>200,000). EFdA's potency and selectivity index is by orders of magnitude more favorable than all currently-approved anti-HIV drugs. Despite the presence of a 3'-OH, the incorporated EFdA-monophosphate acts primarily as an immediate chain terminator because RT has difficulty translocating on the primer possessing 3'-terminal EFdA-MP, which is a unique mechanism of action. Therefore, EFdA-TP is a Translocation-Defective RT inhibitor (TDRTI). Additionally, EFdA has also been shown to efficiently inhibit clinically-important NRTI-resistant HIV strains, and demonstrating hypersusceptibility to the tenofovir-resistant K65R HIV. Notably, in our study of SIV-infected macaques the animals that had suppressed viral loads upon treatment with EFdA carried the M184V mutation, suggesting that M184V can be effectively suppressed by EFdA. We have also shown that EFdA has a remarkably high barrier for HIV resistance, and many EFdA-resistant HIV strains have reduced replication capacity. More recently we have shown that the combination of EFdA with Rilpivirine shows a synergistic effect, which would be useful in the design of new therapeutic regimens. We will build on our work from the first funding cycle to understand the potency of EFdA at the RT and cellular levels, development of EFdA resistance, and EFdA combinations with currently-approved anti-HIV drugs. We will also use biochemical and structural approaches to characterize the inhibition mechanism of EFdA at the RT level, the activation of EFdA by deoxycytidine kinase (dCK) and deamination by adenosine deaminase (ADA). This study will provide information that will guide the design of novel NRTIs and EFdA combination therapies with other approved anti-HIV drugs that may lead to a breakthrough in the treatment of HIV infection.