Targeting M1/M3 Muscarinic Receptors to Treat Gestational Pesticide Poisoning

靶向 M1/M3 毒蕈碱受体治疗妊娠期农药中毒

基本信息

批准号：
10287091
负责人：
RAO P GULLAPALLI
金额：
$ 38.62万
依托单位：
UNIVERSITY OF MARYLAND BALTIMORE
依托单位国家：
美国
项目类别：
财政年份：
2018
资助国家：
美国
起止时间：
2018-06-01 至 2022-12-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10287091
关键词：
Accounting Acetylcholine Acetylcholinesterase Acute Adolescent Alzheimer&apos s Disease Amyloid beta-Protein Biological Assay Blood - brain barrier anatomy Brain Brain region Cavia Chlorpyrifos Clinical Cognitive deficits Complex Contrast Media Deposition Development Disease Dose Environmental Risk Factor Enzymes Exposure to Funding Future Gadolinium Gene Mutation Genes Genetic Genetic Polymorphism Grant Health Hippocampus (Brain)Image Enhancement In Vitro Intercellular Fluid Intoxication Male Adolescents Measures Mediating Memory impairment Modeling Molecular Target Muscarinic M3 Receptor Mutation Nerve Degeneration Neurodegenerative Disorders Neurotransmitters Parents Pathology Pharmacotherapy Poisoning Positron-Emission Tomography Prefrontal Cortex Pregnancy Prevalence Reporting Transgenic Mice Work base behavior test blood-brain barrier disruption contrast enhanced effective therapy familial Alzheimer disease gadobutrol glymphatic system male memory recognition microPET multidisciplinary myoinositol neuron loss neuropathology organophosphorus insecticide pesticide poisoning preclinical study prevent public health relevance tau Proteins

项目摘要

ABSTRACT Acute poisoning with organophosphorus (OP) insecticides, including chlorpyrifos (CPF), the focus of the parent R01 grant, is well-described and results from irreversible inhibition of acetylcholinesterase (AChE), the enzyme that hydrolyzes the neurotransmitter acetylcholine (ACh). Equally worrisome, however, are the detrimental health effects associated with exposures to OP insecticide levels that do not cause marked AChE inhibition and do not trigger acute intoxication. These subacute OP exposures have been associated with increased prevalence of neurodegenerative diseases, including Alzheimer’s disease (AD). Earlier preclinical studies have also reported that CPF and its oxon metabolite aggravate AD-related neuropathology in male transgenic mice carrying gene mutations associated with familial AD (FAD), which accounts for <10% of all cases of AD. Sporadic AD (SAD) is the more prevalent form of the disease, accounting for >90% of all AD cases. SAD has a late onset and a rather complex genetic component, with mutations and polymorphisms of multiple genes likely interacting with each other and with environmental factors. Results generated to date with funds from a previous supplement revealed that recognition memory deficits become evident 7-8 months after a 10- day exposure of male adolescent guinea pigs to a non-AChE inhibiting dose of CPF (2.5 mg/kg/day) and that these deficits are accompanied by increases in hippocampal levels of myoinositol (a metabolite whose levels rise before significant neuronal loss is detected in AD). We also detected, by means of quantitative PCR, a significant increase in the expression of the AD-related gene that encodes the tau protein in the hippocampus of CPF-exposed male guinea pigs. Earlier in vitro studies have suggested that CPF can disrupt the blood brain barrier (BBB) integrity. This is of utmost relevance because Aβ deposits are reportedly cleared from the brain by transport across the BBB and by the astroglial- mediated interstitial fluid bulk flow referred to as the glymphatic system. The objectives of the present study are: (i) to analyze, by means of T1-weighted dynamic contrast-enhanced (DCE) imaging using Gadobutrol, a gadolinium-based contrast agent, the BBB integrity in different brain regions at 1 and 9 months after exposure of adolescent guinea pigs to non-AChE inhibiting CPF doses, and (ii) to analyze, by means of micro PET scan using 18F-Florbetapir (Amyvid), A accumulation, particularly in the hippocampus and the prefrontal cortex. The magnitude of BBB disruption and A accumulation will be correlated with the degree of cognitive deficits measured in behavioral tests and neurodegeneration assayed immunohistochemically. The results of the present study and those generated in the previous supplement will serve the basis for an R01 application aimed at identifying mechanisms that contribute to AD-related pathology precipitated by environmental factors. A mechanistic framework is critically needed for hypothesis-driven studies aimed at identifying effective treatments to prevent and/or stall progression of this catastrophic disease.

抽象的有机磷（OP）杀虫剂急性中毒，包括毒死蜱（CPF），家长关注的焦点 R01 授予，已有详细描述，是乙酰胆碱酯酶 (AChE) 不可逆抑制的结果，该酶然而，同样令人担忧的是疼痛。与接触不引起明显乙酰胆碱酯酶抑制的 OP 杀虫剂水平相关的健康影响并且不会引发急性中毒。这些亚急性有机磷暴露与增加有关。神经退行性疾病的流行，包括阿尔茨海默氏病（AD）。还报道CPF及其oxon代谢物加重雄性转基因小鼠的AD相关神经病理学携带与家族性 AD (FAD) 相关突变的基因，占所有 AD 病例的比例<10%。散发性 AD (SAD) 是该疾病更常见的形式，占所有 AD 病例的 90% 以上。发病较晚，遗传成分相当复杂，可能存在多个基因的突变和多态性相互之间以及与环境因素相互作用的结果。之前的补充表明，认知记忆缺陷在 10-8 个月后 7-8 个月变得明显。雄性青春期豚鼠每天暴露于非乙酰胆碱酯酶抑制剂量的 CPF（2.5 毫克/公斤/天）并且这些缺陷伴随着海马肌醇水平的增加（a 我们还检测到，在 AD 中检测到显着的神经元损失之前，其水平会升高。通过定量PCR的手段，AD相关基因的表达显着增加，编码暴露于 CPF 的雄性豚鼠海马中的 tau 蛋白。有研究表明，CPF 会破坏血脑屏障（BBB）的完整性，这一点至关重要。因为据报道 Aβ 沉积物通过穿过 BBB 的运输和星形胶质细胞从大脑中清除。介导的间质液大量流动称为类淋巴系统本研究的目的。是：（i）通过使用钆布醇的 T1 加权动态对比增强（DCE）成像来分析钆基造影剂暴露后1个月和9个月不同脑区的血脑屏障完整性青春期豚鼠接受非乙酰胆碱酯酶抑制 CPF 剂量的情况，以及 (ii) 通过显微 PET 扫描进行分析使用 18F-Florbetapir (Amyvid)，A 积累，特别是在海马体和前额叶皮层。 BBB 破坏和 A 积累的程度与认知缺陷的程度相关通过行为测试和免疫组织化学测定的神经退行性变进行测量。本研究和之前补充中生成的研究将作为 R01 申请的基础旨在确定环境因素引发 AD 相关病理的机制。旨在确定有效性的假设驱动研究迫切需要一个机制框架预防和/或阻止这种灾难性疾病进展的治疗。