Long-acting aldicarb hydrolase as a medical countermeasure for aldicarb poisoning

长效涕灭威水解酶作为涕灭威中毒的医学对策

• 批准号: 10724752
• 负责人: CHANG-GUO ZHAN
• 金额: $ 53.3万
• 依托单位: UNIVERSITY OF KENTUCKY
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-01 至 2025-08-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10724752
• 关键词: Acetylcholinesterase; Acetylcholinesterase Inhibitors; Acute; Aerosols; Aftercare; Air; Aldicarb; Animal Model; Animals; Atropine; Binding; Biological Assay; Brain; Butyrylcholinesterase; Carbamates; Categories; Cavia; Chemical Warfare; Chemicals; Clinical; Cocaine; Cocaine use disorder; Computer Models; Control Groups; Convulsions; Corn Oil; Data; Development; Dose; Drug Metabolic Detoxication; Engineering; Enzymes; Evaluation; Exposure to; Future; Hour; Human Engineering; Hydrolase; Hydrolysis; Hyperactivity; In Vitro; Intoxication; Investigation; Lead; Lethal Dose 50; Libraries; Literature; Molecular; Mus; Oral; Organophosphorus Compounds; Outcome; Oximes; Paraoxon; Pesticides; Phosphorylation; Poisoning; Polymers; Proteins; Rattus; Reaction; Reporting; Research; Safety; Sarin; Security; Soman; Talc; Testing; Toxic effect; absorption; acute toxicity; aged; bioscavenger; blood-brain barrier crossing; cholinergic; clinical candidate; clinical development; computer studies; cyclosarin; dermal exposure; drug candidate; experience; experimental study; exposure route; immunogenicity; improved; in vivo; intraperitoneal; lead optimization; mass casualty; medical countermeasure; mortality; nerve agent; neurotoxicity; novel; pharmacokinetics and pharmacodynamics; physical property; preclinical development; programs; rational design; success; tabun

As one of the Chemicals of Concern (CoC) identified by the US Department of Homeland Security, aldicarb belongs to the Cholinergic Warfare and Pesticides category. As the most toxic carbamate pesticide – a potent, fast-acting inhibitor of acetylcholinesterase (AChE), aldicarb is readily absorbed from all routes of exposure, including oral and dermal exposure. In all species tested, the acute oral toxicities of aldicarb are similar. Due to its physical properties documented in literature, aldicarb could be used by terrorists to cause mass casualty. Organophosphorus (OP) warfare/pesticides and carbamate pesticides have a common mode of action for their neurotoxicity as AChE inhibitors. Currently available options for treating this type of poisoning, such as administration of atropine or co-administration of atropine and pralidoxime (2-PAM), have limited efficacy. There have been extensive efforts in development of improved options for treatment of OP poisoning. Relatively less studies have been carried out in development of aldicarb poisoning treatment. Reported studies indicated that 2-PAM had neither positive nor negative effects on survival in animal studies on aldicarb intoxication. This outcome is understandable, as 2-PAM was developed to reactivate phosphorylated AChE (an intermediate formed from the inhibition reaction of AChE with an OP), but not carbamylated AChE (an intermediate formed from the reaction of AChE with a carbamate like aldicarb). It is highly desired to develop a new, effective post- exposure treatment option for aldicarb poisoning. This investigation will focus on rational design and discovery of an engineered enzyme capable of rapidly and efficiently detoxifying aldicarb as a catalytic aldicarb bioscavenger for aldicarb poisoning. As an effective bioscavenger, it must be able to react with aldicarb more rapidly than AChE so as to protect AChE from reaction (carbamylation) with aldicarb. In preliminary studies, we have demonstrated that an Fc-fused cocaine hydrolase (Fc-CocH), developed previously in our lab for treatment of cocaine use disorders (CUDs), can more potently bind with aldicarb than with AChE and wild-type butyrylcholinesterase (BChE) and can also catalyze aldicarb hydrolysis. In further in vivo rescue experiment, this Fc-CocH protein powerfully rescued all mice that had been injected intraperitoneally (IP) with a lethal dose (~2 × LD50) of aldicarb. With the encouraging preliminary data, taking advantage of our positive experience in preclinical and clinical development of Fc-CocHs, we propose to first evaluate an in-house library of Fc-CocHs for their activities with aldicarb in order to select the one with the highest catalytic activity for aldicarb hydrolysis and the best overall in vivo profiles, followed by lead optimization to optimize its catalytic activity against aldicarb, substrate selectivity, post-exposure in vivo efficacy, and toxicity/immunogenicity profiles. Accomplishment of this investigation will deliver a couple of safe, highly efficient aldicarb hydrolases that are promising for treatment of aldicarb poisoning. The one with the best overall in vivo profiles will serve as a clinical candidate, and the second best will serve as a backup, for further preclinical and clinical development in the future.

作为美国国土安全部确定的关注化学品（COC），Aldicarb 属于胆碱能战和农药类别。作为最有毒的氨基甲酸酯农药 - 潜力， 乙酰胆碱酯酶的快速作用抑制剂（ACHE），Aldicarb易于从所有暴露途径中吸收 包括口腔和皮肤暴露。在所有测试的物种中，alikarb的急性口服毒性相似。由于 恐怖分子可以使用其在文献中记录的物理特性，以造成大规模伤亡。 有机磷（OP）战争/农药和氨基甲酸酯农药具有共同的作用方式 神经毒性作为ACHE抑制剂。目前可用于治疗此类中毒的选项，例如 芳香氨酸和普拉迪毒素（2-PAM）的香气或共同给药的效率有限。那里 在改善治疗OP中毒的选择方面已经进行了广泛的努力。相对较少 已经在alidicarb中毒治疗的发展中进行了研究。报道的研究表明 在动物研究中，2-PAM对阿里卡布中毒的动物研究既没有正面的影响。这 结果是可以理解的，因为开发了2-PAM以重新激活磷酸化的ACHE（中间体 由ACHE与OP的抑制反应形成），而不是甲酰化的ACHE（形成的中间体 从ACHE与Aldicarb这样的氨基甲酸酯的反应中。非常希望开发一个新的，有效的后 - aldicarb中毒的暴露治疗选择。这项投资将重点放在理性的设计和发现上 能够快速有效地将alidicarb排毒为催化alidicarb的工程酶 作为有效的Bioscavenger，它必须能够与AlidiCarb做出更多反应 比疼痛迅速，以保护疼痛免受抗反应（卡氨基化）的影响。在初步研究中，我们 已经证明了FC融合的可卡因水解酶（FC-Coch）先前在我们的实验室进行治疗 可卡因的使用障碍（CUD）可以与AlidiCarb相比，与ACHE和野生型更重要 丁酰胆碱酯酶（BCHE），还可以催化α的水解。在进一步的体内救援实验中， FC-Coch蛋白有力地挽救了所有已腹膜内注射（IP）的小鼠（〜2） ×aldicarb的ld50）。有了令人鼓舞的初步数据，利用了我们的积极经验 FC-Cochs的临床前和临床开发，我们建议首先评估FC-Cochs内部库 为了选择Aldicarb的活动，以便选择具有最高催化活性的Aldicarb水解的活动 以及最佳的整体体内轮廓，然后进行铅优化，以优化其针对Aldicarb的催化活性， 底物选择性，体内暴露后效率和毒性/免疫原性谱。实现这一目标 调查将提供几个安全，高效的Aldicarb水解酶，并承诺用于治疗 Aldicarb中毒。具有最佳整体体内轮廓的最佳的临床候选者，第二个 Best将作为备份，以便将来进一步临床前和临床发展。