Brain-penetrating acetylcholinesterase reactivators for several organophosphates

几种有机磷酸酯的脑穿透性乙酰胆碱酯酶再激活剂

基本信息

批准号：
8846691
负责人：
Janice Elaine Chambers
金额：
$ 71.47万
依托单位：
MISSISSIPPI STATE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2014
资助国家：
美国
起止时间：
2014-06-01 至 2017-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8846691
关键词：
Accidents Accounting Acetylcholinesterase Acetylcholinesterase Inhibitors Atropine Attenuated Behavior Behavioral Blood Blood - brain barrier anatomy Brain Brain Injuries Cerebrospinal Fluid Cessation of life Chemicals Chemistry Cholinesterase Inhibitors Cognitive deficits Convulsants Development Diazepam Docking Dose Drug Kinetics Exposure to F2-Isoprostanes General Population Glial Fibrillary Acidic Protein Goals Health Hepatic In Vitro Insecticides Japanese Population Laboratories Lead Libraries Life Long-Term Effects Measures Metabolism Microdialysis Mississippi Modeling Muscarinic Antagonists Nerve Degeneration Nervous System Trauma Neurologic Organophosphates Outcome Oxidative Stress Oximes Paraoxon Parathion Penetration Peripheral Peripheral Nervous System Plasma Proteins Poison Poisoning Protein Binding Publishing Rattus Research Project Grants Risk Sarin Seizures Structure Subway Survivors Synthesis Chemistry Testing Therapeutic Agents Translational Research Universities attenuation chemical synthesis computational chemistry design dosage efficacy testing excitotoxicity improved in vivo inorganic phosphate lipophilicity molecular dynamics nerve agent neuron apoptosis neuropathology neuroprotection novel novel therapeutics organophosphate poisoning prevent research study screening toxic organophosphate insecticide exposure

项目摘要

DESCRIPTION (provided by applicant): Organophosphate (OP) anticholinesterases, e.g., nerve agents or insecticides, are potent acetylcholinesterase (AChE) inhibitors. High dose poisoning causes excitotoxicity that leads to seizures and subsequently brain damage. The current therapy in the US includes an oxime reactivator, 2-PAM, which has little, if any, ability t cross the blood-brain barrier (BBB) and consequently cannot stop seizures and prevent brain damage. Our laboratories have developed a library of phenoxyalkyl pyridinium oximes designed to have greater lipophilicity than 2-PAM. Through a paradigm using high sub-lethal dosages of highly relevant surrogates for sarin or VX in rats and administering the novel oximes at 1 hr after OP compound treatment when seizure behavior was on- going, we have demonstrated the ability of a number of these oximes to penetrate the BBB, reactivate AChE, and to attenuate seizure behavior. The objective of this application is to further characterize a limited number of these novel oximes (initially 6, then down-selected to 3) to ultimately select a single lead oxime for an IND application. Additionally we will expand the OP chemistries tested to include an insecticidal chemistry, paraoxon (the active metabolite of parathion; tested first to avoid any confounders that could occur because of the need for bioactivation) and parathion. Endpoints of characterization include brain and peripheral AChE reactivation, seizure attenuation, neurodegeneration (glial fibrillary acidic protein accumulation), oxidative stress (F2-isoprostanes), neuropathology (apoptosis, neuron survival), and behavior. Concurrently molecular dynamics computations will determine if one or two additional oxime structures are predicted to have greater efficacy than our current selections; if so, it/they will be synthesized and substituted for our current selections. The specific aims of the proposed project are: 1. In vivo efficacy characterization aim: To provide expanded measures of neuroprotection on our currently identified BBB-penetrating oximes using the sarin and VX surrogates and also a common insecticidal OP chemistry (i.e., diethyl phosphate) using parathion and its active metabolite paraoxon. Efficacy endpoints for the 4 OP's include: 1a, efficacy screening endpoints with 6 oximes: reactivating rat brain AChE, and the attenuation of seizure behavior and neurodegeneration; and 1b, detailed efficacy characterization endpoints with 3 down-selected oximes: oxidative stress in the brain, neuropathology and behavioral deficits. 2. Pharmacokinetic aim: To determine for the 3 down-selected oximes hepatic in vitro metabolism, plasma protein binding and levels of oxime in the blood and cerebrospinal fluid (obtained through microdialysis). 3. Computational chemistry aim: To model the docking of oxime with AChE and BBB penetration to suggest improved oxime structures. 4. Chemical synthesis aim: To produce sufficient quantities of the test OP's and the test oximes for the experiments proposed, as well as the synthesis of a few new oximes if suggested by the computational chemistry aim. The ultimate outcome will be the identification of the most efficacious novel oxime for further development as a potential substitute for current therapy.

描述（由申请人提供）：有机磷酸酯（OP）抗胆碱酯酶，例如神经毒剂或杀虫剂，是有效的乙酰胆碱酯酶（AChE）抑制剂。高剂量中毒会引起兴奋性中毒，导致癫痫发作并随后导致脑损伤。美国目前的治疗方法包括肟重激活剂 2-PAM，它几乎没有穿过血脑屏障 (BBB) 的能力，因此无法阻止癫痫发作和预防脑损伤。我们的实验室开发了苯氧基烷基吡啶鎓肟库，其亲脂性比 2-PAM 更高。通过在大鼠中使用高亚致死剂量的高度相关的沙林或 VX 替代物并在给药后 1 小时施用新型肟的范例当癫痫发作行为持续时，使用 OP 化合物进行治疗，我们已经证明了许多这些肟能够穿透 BBB、重新激活 AChE 并减弱癫痫发作行为。本申请的目的是进一步表征有限数量的这些新型肟（最初为 6 个，然后向下选择至 3 个），以最终选择用于 IND 应用的单一铅肟。此外，我们将扩大测试的 OP 化学物质，包括杀虫化学物质、对硫磷（对硫磷的活性代谢物；首先进行测试以避免由于需要生物活化而可能发生的任何混杂因素）和对硫磷。表征终点包括大脑和外周 AChE 重新激活、癫痫发作减弱、神经变性（胶质纤维酸性蛋白积累）、氧化应激（F2-异前列腺素）、神经病理学（细胞凋亡、神经元存活）和行为。同时分子动力学计算将确定是否预测一种或两种额外的肟结构比我们当前的选择具有更大的功效；如果是这样，它/它们将被合成并替换我们当前的选择。拟议项目的具体目标是： 1. 体内功效表征目标：使用沙林和 VX 替代物以及常见的杀虫 OP 化学物质（即磷酸二乙酯），为我们目前确定的 BBB 穿透肟提供扩展的神经保护措施。使用对硫磷及其活性代谢物对氧磷。 4 种 OP 的功效终点包括： 1a，6 种肟的功效筛选终点：重新激活大鼠脑 AChE，以及癫痫行为和神经变性的减弱； 1b，3 个向下选择的肟的详细功效表征终点：大脑中的氧化应激、神经病理学和行为缺陷。 2.药代动力学目的：测定3种下调选择的肟的体外肝代谢、血浆蛋白结合以及血液和脑脊液中肟的水平（通过微透析获得）。 3. 计算化学目标：模拟肟与 AChE 和 BBB 渗透的对接，以提出改进的肟结构。 4.化学合成目标：为所提出的实验生产足够数量的测试OP和测试肟，以及如果计算化学目标建议的话合成一些新的肟。最终结果将是鉴定出最有效的新型肟，以进一步开发作为当前疗法的潜在替代品。