Environmental Metals, Excitotoxicity and ALS

环境金属、兴奋性毒性和 ALS

基本信息

批准号：
9033912
负责人：
William D Atchison
金额：
$ 44.94万
依托单位：
MICHIGAN STATE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2015
资助国家：
美国
起止时间：
2015-03-12 至 2019-12-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9033912
关键词：
Address Adult Affect Amino Acid Transporter Amyotrophic Lateral Sclerosis Antioxidants Astrocytes Cells Cessation of life Chimera organism Chronic Coculture Techniques DNA Sequence Alteration Development Disease Disease Progression Divalent Cations Dose Environment Environmental Exposure Event Excitatory Amino Acids Exposure to Functional disorder Generations Genes Glutamate Transporter Glutamates Glutathione Goals Health Homeostasis Human Lesion Measures Mediating Mercury Metal exposure Metals Methylmercury Compounds Mitochondria Motor Motor Neurons Mus Mutation Nerve Degeneration Neurodegenerative Disorders Neuronal Injury Neurons Onset of illness Oxidative Stress Pathogenesis Phenotype Play Population Process Production Proteins Reactive Oxygen Species Regulation Risk Factors Role Secondary to Single Nucleotide Polymorphism Slice Spinal Cord Staging System Testing Text Time Toxic Environmental Substances Toxic effect Transgenic Mice base cell type comparative course development design early onset environmental agent excitotoxicity gene environment interaction genetic linkage mRNA Expression mitochondrial dysfunction motor neuron development motor neuron function mouse model mutant overexpression postnatal postsynaptic pre-clinical progressive neurodegeneration research study response superoxide dismutase 1 synaptic function uptake

项目摘要

DESCRIPTION (provided by applicant): Amyotrophic lateral sclerosis (ALS), or Lou Gehrig's disease, is a progressive neurodegenerative disease resulting in motor nerve degeneration and death. Both familial (FALS) and sporadic (SALS) forms exist; the latter greatly predominate. Its cause is unknown. Overstimulation of glutamatergic function - excitotoxicity - with increased Ca2+ and generation of reactive oxygen species (ROS), plays an important, if not integral role, though other mechanisms likely contribute to ALS pathogenesis. Interaction of motor neurons (MNs) and astrocytes (ASTs) appear to contribute to disease development. Environmental contribution to ALS has been postulated often, but to date not systematically tested. We propose to examine the interaction of the environmental toxicant methylmercury (MeHg) with two genetic mutations found in humans with ALS. Chronic postnatal MeHg exposure of mice with a mutation in superoxide dismutase-1 (SOD1G93A, G93A) hastens the onset of ALS phenotype compared to untreated G93A mice or wt mice exposed to identical MeHg concentrations. We will now test the hypothesis that chronic, low dose, MeHg exposure beginning postnatally enhances development and progression of ALS phenotype in the G93A and G85R SOD1 mutants by increasing [Ca2+]i, generating ROS and inducing mitochondrial toxicity secondary to enhanced release of glutamate (Glu) or actions on AST Glu transporters (EAAT1-2). The two SOD1 mutant strains differ in their time course of development of ALS phenotype and in their primary toxic focus. The G93A mice develop phenotype in ~4 mos and disease is MN-directed. G85R mice develop ALS phenotype over 7-9 months and disease is AST-based. This design will allow us to compare the roles of ASTs and MNs to MeHg induced responses. Specific Aim 1: Examines the development of ALS phenotype and relative role of MNs and ASTs during chronic adult MeHg exposure. Specific Aim 2: Examines oxidative stress as a contributor to MeHg-induced enhancement of ALS phenotype. Specific Aim 3: Examines the cell autonomy of MN function in response to MeHg. Interactions between ASTs and MNs will be examined in chimeric cultures of wt and SOD-1 cells to assess their potential roles in the development of excitotoxicity in MeHg-induced enhancement of ALS phenotype. Early onset effects preceding development of ALS phenotype will be examined using spinal cord slices and co-cultures of MNs and ASTs, from the G93A and G85R strains. Glu-mediated excitatory postsynaptic currents and elevation of [Ca2+] i and levels of ROS will test for MeHg-induced excitotoxicity. Steady- state mRNA expression levels for EAAT1-2 and proteins involved in [Ca2+] i regulation will be measured during development of ALS phenotype to correlate with studies done in cells in culture. MNs in culture derived from SOD1 mice or wt will allow examination of early effects of MeHg on Glu function, [Ca2+] i oxidative stress or mitochondrial damage in isolation. Results of the proposed study should permit assessment of the role of MeHg-induced Glu- mediated excitotoxicity in facilitating development of MN dysfunction and provide verification for the postulate that environmental exposure to metals is a potential risk factor for susceptible populations in development of ALS.

描述（由适用提供）：肌萎缩性侧面硬化症（ALS）或Lou Gehrig病，是一种进行性神经退行性疾病，导致运动神经退化和死亡。家庭（fals）和零星（萨尔斯）形式都存在；后者极为占主导地位。它的原因是未知的。谷氨酸能功能的过度刺激 - 兴奋性毒性 - Ca2+增加，而活性氧（ROS）的产生增加，即使不是不可或缺的作用，尽管其他机制可能有助于ALS发病机理。运动神经元（MN）和星形胶质细胞（AST）的相互作用似乎有助于疾病的发展。经常假定对ALS的环境贡献，但迄今为止未进行系统测试。我们建议检查环境有毒物质甲基汞（MEHG）与ALS人类中发现的两个遗传突变的相互作用。与未经治疗的G93A小鼠相比，超氧化物歧化酶1（SOD1G93A，G93A）在超氧化物歧化酶1（SOD1G93A，G93A）中突变的小鼠的慢性MEHG暴露会加速ALS表型的发作。现在，我们将检验以下假设：慢性，低剂量的MEHG暴露在产后开始增强ALS表型在G93A和G85R SOD1突变体中通过增加[Ca2+] I的[Ca2+] I，生成ROS并诱导的线粒体毒性二次释放到Glutamate（Glu）（Glu）或AST GRAT（AST GRAT）（AST GRAT）（AST GRAT）（AST GRAT）（AST GRAT）（aST GRAT）。在ALS表型的开发时间和主要有毒重点中，两个SOD1突变体菌株不同。 G93A小鼠在〜4个MOS中形成表型，并且疾病是Mn导向的。 G85R小鼠在7-9个月内发展出ALS表型，疾病基于AST。这种设计将使我们能够比较特定角色的目标1：检查ALS表型的发展以及MN和AST在慢性成人MEHG暴露期间的相对作用。特定目的2：检查氧化应激是导致MEHG诱导的ALS表型增强的原因。特定目的3：检查MN功能的细胞自主性，以响应MEHG。 AST和MN之间的相互作用将在WT和SOD-1细胞的嵌合培养物中进行检查，以评估其在MEHG诱导的ALS表型增强中兴奋性毒性发展中的潜在作用。 ALS表型发育之前的早期发作效应将使用G93A和G85R菌株的MN和ASTS的脊髓切片和共培养。 GLU介导的兴奋性突触后电流和[Ca2+] I的升高和ROS水平将测试MEHG诱导的兴奋性毒性。 EAAT1-2的稳态mRNA表达水平和参与[Ca2+] I调控的蛋白质的稳态mRNA表达水平将在ALS表型的开发过程中测量，以与培养细胞中的研究相关。源自SOD1小鼠或WT的培养物中的MN将允许检查MEHG对GLU功能的早期作用，[Ca2+] I氧化应激或线粒体损伤分离。拟议的研究的结果应允许评估MEHG诱导的GLU介导的兴奋性在支持MN功能障碍发展中的作用，并为假定金属的环境暴露是ALS发育中敏感人群的潜在风险因素提供了验证。