High-throughput assays and small-molecule discovery of antiviral candidates targeting influenza hemagglutinin

项目摘要/摘要 甲型流感病毒表现出极端的多样性，血凝素的多种血清型就是例证 (HA，H1-H18)和神经氨酸酶(NA，N1-N11)表面抗原。到目前为止，198种可能的组合中只有3种 禽类和其他动物宿主中的HA和NA与人类大流行(H1N1、H2N2、 H3N2)。最近在人类身上出现的H5N1、H6N1、H7N7、H7N9、H9N2和H10N8不断提醒人们 有可能引发毁灭性的新流行病。乙型流感病毒及其两个谱系进一步增加了 季节性流感的健康和经济负担。目前还没有有效的抗病毒药物可用于 防止甲型或乙型流感病毒进入宿主细胞(科学前提)。然而，相对较近的是 人类流感病毒广谱中和抗体的发现及其结构研究 已确定医管局在大流行、季节性和新出现的流感病毒中易受攻击的部位。这些 HA表面部位包括受体结合部位和容纳融合机制的膜-近端茎， 这两种物质对细胞感染都是必不可少的。识别这些站点的常见特征现在可以是 在小分子设计中被利用，最终开发出广泛适用的流感抗病毒药物。 在这里，我们将使用这些结构信息来优化和执行高通量分析 以高度保守和脆弱的茎结合位点为靶点的新的小分子支架。高- 将对来自甲型流感1组的代表性HAS进行平行的吞吐量筛查，以对抗600K 结构多样的分子(SA1)。我们还将研究2组流感和B型流感的300K化合物 屏幕(SA2)。验证的HIT化合物将根据HAS和TOP之间的亲和力和广度进行优先排序 候选人将通过x射线结构设计严格优化为铅分子，并与药物循环 化学反应。生物物理结合、细胞感染性和耐药性分析(例如，HA的组合病毒库 突变体)将有助于迭代设计、选择和表征潜在的新型候选治疗方法 良好的类药物特性。所有这些方法都在沃兰和威尔逊实验室中得到了积极的应用。 作为这种方法的概念验证，我们确定了与基团1的茎具有适度亲和力的分子 用我们自己设计的超音速测定法。它与羟基磷灰石的共晶结构为设计提供了关键信息 和合成了一个聚焦的化合物文库，我们用它来制备立体选择性分子 纳摩尔亲和力和抗病毒活性。我们的总体目标是鉴定和改进具有广泛效力的分子。 针对第一组和第二组的茎，以及流感B组。据我们所知，我们是第一个设计出一种化验方法的 对抗组2和乙型流感已经服从HTS(创新)。我们预计有几类针对干细胞的 复合支架将被鉴定为具有纳米分子亲和力的具有细胞抗病毒活性和合适的 PK-ADME属性。未来的努力将包括流感感染的动物模型，以进一步验证我们的 抗病毒药物，最终目标是抗击未来的流感大流行和季节性流行病。

PROJECT SUMMARY / ABSTRACT Influenza A viruses exhibit extreme diversity as exemplified by the multiple serotypes of the hemagglutinin (HA, H1-H18) and neuraminidase (NA, N1-N11) surface antigens. To date, only 3 of 198 possible combinations of HA and NA in avian and other animal reservoirs have been associated with human pandemics (H1N1, H2N2, H3N2). Recent appearances of H5N1, H6N1, H7N7, H7N9, H9N2, and H10N8 in humans are constant reminders of the potential for devastating new pandemics. Influenza B viruses with its two lineages further increase the health and economic burdens of seasonal influenza. No effective antiviral drugs are currently available for preventing entry of influenza A or B viruses into host cells (scientific premise). However, relatively recent discoveries of broadly neutralizing antibodies to human influenza viruses and concomitant structural studies have identified sites-of-vulnerability on the HA in pandemic, seasonal, and emerging influenza viruses. These HA surface sites include the receptor binding site and membrane-proximal stem housing the fusion machinery, both of which are essential for cellular infection. Common features for recognition of these sites can now be exploited in design of small molecules to ultimately develop broadly applicable influenza antivirals. Here, we will employ this structural information into the optimization and execution of high-throughput assays to identify new small-molecule scaffolds that target the highly conserved and vulnerable stem-binding site. High- throughput screening will be performed in parallel on representative HAs from influenza A group 1 against 600K structurally diverse molecules (SA1). We will also subject group 2 and influenza B HAs to a 300K compound screen (SA2). Validated hit compounds will be prioritized based on affinity and breadth across HAs and top candidates will be rigorously optimized into lead molecules by x-ray structure-based design cycled with medicinal chemistry. Biophysical binding, cellular infectivity and resistance assays (e.g., combinatorial viral libraries of HA mutants) will aid in iterative design, selection, and characterization of potential novel therapeutic candidates with favorable drug-like properties. All of these methods are actively employed in the Wolan and Wilson laboratories. As proof-of-concept for this approach, we identified a molecule with modest affinity to the stem of group 1 HAs with an HT assay of our own design. Its co-crystal structure with HA provided critical information towards design and synthesis of a focused compound library, which we used to produce a stereoselective molecule with nanomolar affinity and antiviral activity. Our overall goal is to identify and improve molecules with broad potency against the stem of groups 1 and 2 as well as flu B HAs. To our knowledge, we are the first to design an assay against group 2 and flu B HAs amenable to HTS (innovation). We anticipate that several classes of stem-targeted compound scaffolds will be identified with nanomolar affinity to HAs with cellular antiviral activity and suitable PK-ADME properties. Future efforts will include animal models of influenza infections to further validate our antivirals with the ultimate goal of combatting future influenza pandemics and seasonal epidemics.