Quinoline-based Inhibitors of BoNT/A LC

描述（由申请人提供）：肉毒杆菌神经毒素（BoNTs）是已知最毒的生物物质。血清A型BoNT （BoNT/A）在人体内的致死静脉注射剂量为1-5纳克/公斤。如果意外暴露于BoNT（例如，从受污染的食品中），可能发生生命丧失或危及生命的瘫痪。最重要的是，bont已经被“武器化”为剧毒的气溶胶形式，因此它们对平民和军队都构成了重大威胁。一旦摄入，bont靶向周围胆碱能神经末梢，并通过中断自主神经功能导致死亡。BoNTs的锌依赖性内肽酶轻链（LC）部分通过对神经传递中必需的SNARE（可溶性n -乙基马来酰亚胺敏感因子附着蛋白受体）成分的蛋白质水解而损害神经元胞外分泌。本项目的总体目标是开发BoNT/A轻链金属蛋白酶活性的小分子抑制剂来治疗肉毒杆菌中毒。我们的策略是优化一种新的BoNT/ a LC抑制剂的化学类型，以提高效力、选择性和药物样性质。在初步研究中，我们改进了结构，为药物化学提供了一个新的起点，该化学核心具有比原始化合物系列更类似药物的性质，并且具有十倍的效力。在BoNT/ a中毒的鸡神经元细胞模型中也观察到显著的活性。这些经过验证的早期先导化合物比原始系列更适合用于BoNT/A抑制剂药物的开发，并且它们为生成高级先导化合物的优化程序奠定了基础。我们在第一阶段的方法是使用经过验证的药物和平行合成化学技术来优化先导系列化合物的效力和选择性，并生产具有推进临床前开发潜力的“类药物”分子。在一个迭代的过程中，我们将通过测量酶和细胞活性以及酶抑制剂的特异性来探测这些重点化合物库的结构特征，这些结构特征有助于更紧密地结合和更有效地抑制BoNT/A金属蛋白酶。我们将把这些化合物对BoNT/A LC的体外活性与BoNT/A作用的细胞模型中的活性联系起来，并使用该系列中最有希望的成员在体内小鼠BoNT/A中毒模型中验证这些抑制剂。在I期结束时，我们将确定一种先进的先导化合物，该化合物将从体内验证的抑制剂组中选择，显示出合适的体外药代动力学特性，用于进一步的临床前开发。在II期，我们将进一步优化和评估先导物在两个物种中的体内疗效、药代动力学特性、毒性和安全药理学，并将其发展为ind前临床候选药物，适合人体临床试验（III期）。

DESCRIPTION (provided by applicant): The botulinum neurotoxins (BoNTs) are the most poisonous biological substances known. The lethal intravenous dose of BoNT serotype A (BoNT/A) in humans is 1-5 ng/kg. If accidental exposure to BoNT occurs (e.g., from contaminated foodstuffs), loss of life or life-threatening paralysis can occur. Most importantly, the BoNTs have already been "weaponized" in a highly toxic aerosol form, and they consequently pose a significant threat to both civilian and military populations. Once ingested, BoNTs target the peripheral cholinergic nerve endings and cause death by interrupting autonomic nerve function. The zinc-dependent endopeptidase light chain (LC) portion of BoNTs impairs neuronal exocytosis through proteolysis of essential SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) components of neurotransmission. The overall goal or this project is to develop small molecule inhibitors of the BoNT/A light chain (LC) metalloprotease activity to treat botulinum poisoning. Our strategy is to optimize a novel chemotype of BoNT/A LC inhibitors to improve potency, selectivity, and drug-like properties. In preliminary studies, we refined the structures to provide a new starting point for medicinal chemistry based on a chemical core with more drug-like properties than the original compound series and with ten-fold better potency. Significant activity was also observed in a chick neuronal cell model of BoNT/A intoxication. These validated early lead compounds are more suitable lead compounds for BoNT/A inhibitor drug discovery than were the original series, and they form the basis for this optimization program to generate an advanced lead compound. Our approach in Phase I is to use proven techniques of medicinal and parallel synthetic chemistry to optimize the potency and selectivity of the lead series of compounds and produce "drug-like" molecules with the potential to advance to pre-clinical development. In an iterative process, we will probe these focused compound libraries for structural features that contribute to tighter binding and more potent inhibition of the BoNT/A metalloprotease by measuring the enzymatic and cellular activities, as well as the specificity of the enzyme inhibitors. We will correlate the in vitro activity of the compounds against BoNT/A LC with activity in a cellular model of BoNT/A action, and use the most promising members of the series to validate the inhibitors in an in vivo mouse model of BoNT/A intoxication. At the end of Phase I we will define an advanced lead compound, which will be selected from the group of in vivo-validated inhibitors that displays suitable in vitro pharmacokinetic properties for further preclinical development. In Phase II, we will further optimize and evaluate the lead for in vivo efficacy, pharmacokinetic properties, toxicity and safety pharmacology in two species, and develop it into a pre-IND clinical candidate, suitable for human clinical trials (Phase III). PUBLIC HEALTH RELEVANCE: The botulinum neurotoxins are some of the most poisonous biologic substances known. Loss of life or life-threatening paralysis can occur following exposure to these neurotoxins from contaminated foodstuffs or acts of bioterrorism. This proposal describes the preparation and development of novel drugs to treat botulinum poisoning.