Drug Discovery Targeting the Influenza A Virus M2-S31N Proton Channel

 描述（由申请人提供）：每年流感流行加上新出现的流感大流行的全球健康负担突出了对新的有效治疗的迫切需求。目前流行的大多数季节性流感病毒，以及高致病性禽流感病毒，如H5 N1和H7N9，在其M2基因中携带S31 N突变体，其赋予对金刚烷（金刚烷胺和金刚乙胺）的抗性。对唯一口服药物奥司他韦耐药的流感病毒持续增加。因此，持续需要新型抗流感药物。M2-S31 N突变在超过95%的目前流行的甲型流感病毒中持续存在，它是一种 最保守的病毒蛋白。因此，靶向M2-S31 N的抑制剂将是下一代抗流感药物的优秀候选者。本研究旨在开发具有良好类药物性质和体内活性的M2-S31 N通道阻断剂。我们实施了一个多方面的方法，包括基于结构的药物设计，药物化学，电生理学和病毒学设计M2-S31 N通道阻滞剂。目标是开发广谱抗病毒药物，其对对目前批准的一类或两类抗流感药物具有耐药性的甲型流感病毒临床分离株具有活性。 在R21阶段，我们将专注于优化我们以前发现的M2-S31 N抑制剂以及探索新的化学型。抑制剂设计将由我们先前解决的M2-S31 N的溶液NMR结构指导。合成的分子将在抗病毒试验中针对对金刚烷胺或奥司他韦或两者均显示耐药性的临床相关甲型流感病毒进行测试。将使用电生理学测定和溶液NMR NOESY光谱法确认作用机制。为了优先考虑体内研究的化合物，我们将分析顶级先导化合物的ADME特性，并评估其引发耐药性的趋势。 在R33阶段，我们将评估以下药物的联合治疗潜力： M2-S31 N抑制剂与奥司他韦或利巴韦林。构效关系研究将由体外ADME性质、细胞毒性以及与奥司他韦或利巴韦林的协同作用驱动。我们将在小鼠中测定多达五种化合物的体内药代动力学ADME特性。对于有效性研究，将用致死剂量的小鼠适应性甲型流感病毒攻击小鼠，并通过经口灌胃或尾静脉注射给予M2-S31 N抑制剂。存活率、体重减轻和其他临床体征将用于评价M2-S31 N抑制剂的体内疗效。 在成功完成拟议研究后，我们将至少有一种化合物可用于下一阶段的研究，以便进行新药临床试验（IND）申报。

 DESCRIPTION (provided by applicant): The global health burden of annual influenza epidemics coupled with emerging influenza pandemics highlight the urgent need for new, effective treatments. The majority of current circulating seasonal influenza viruses, as well as highly pathogenic avian influenza viruses such as H5N1 and H7N9, carry the S31N mutant in their M2 genes, which confers resistance to adamantanes (amantadine and rimantadine). Influenza viruses that are resistant to oseltamivir, the only orally available drug, are continuousy on the rise. Thus there is a persistent need for novel anti-influenza drugs. The M2-S31N mutation is persistent in more than 95% of currently circulating influenza A viruses, and it is one of the most conserved viral proteins. Therefore inhibitors targeting M2-S31N will be excellent candidates for the next generation of anti-influenza drugs. This proposal focuses on developing M2-S31N channel blockers with favorable drug-like properties and in vivo activities. We implement a multi-faceted approach that includes structure-based drug design, medicinal chemistry, electrophysiology, and virology to design M2-S31N channel blockers. The goal is to develop broad spectrum antiviral drugs that are active against clinical isolates of influenza A viruses that are resistant to one or both classes of currently approved anti-influenza drugs. In the R21 phase we will focus on optimizing our previously discovered M2-S31N inhibitors as well as exploring novel chemotypes. The inhibitor design will be guided by our previously solved solution NMR structure of M2-S31N. Synthesized molecules will be tested in antiviral assays against clinically relevant influenza A viruses that show resistance to either amantadine or oseltamivir or both. The mechanism of action will be confirmed using electrophysiological assays and solution NMR NOESY spectroscopy. To prioritize compounds for the in vivo studies, we will profile the ADME properties of top lead compounds as well as evaluate their tendencies to elicit drug resistance. In the R33 phase, we will evaluate the combination therapy potential of M2-S31N inhibitors with oseltamivir or ribavirin. The structure-activity relationship studies will e driven by the in vitro ADME properties, cytotoxicity, and synergistic effects with oseltamivir or ribavirin. We will assay the in vivo pharmacokinetic ADME properties of up to five compounds in mice. For efficacy studies, mice will be challenged with a lethal dose of mouse-adapted influenza A viruses, and M2-S31N inhibitors will be administrated by oral gavage or tail vein injection. Survival rate, body weight loss, and other clinical signs will be used to evaluate the i vivo efficacy of M2-S31N inhibitors. Upon successful completion of the proposed studies, we will have at least one compound that is ready for the next stage of studies needed for Investigational New Drug (IND) filling.