Molecular mechanism of acidotoxicity to neurons

神经元酸毒性的分子机制

• 批准号: 9367941
• 负责人: MICHAEL X ZHU
• 金额: $ 33.45万
• 依托单位: UNIVERSITY OF TEXAS HLTH SCI CTR HOUSTON
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-06-15 至 2022-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9367941
• 关键词: ASIC channel; Acidosis; Acids; Adverse effects; Alzheimer' s Disease; Amyotrophic Lateral Sclerosis; Binding; Brain Injuries; Brain Ischemia; C-terminal; Cations; Cell Death; Cell surface; Cells; Cessation of life; Complex; Coupling; Dependence; Encephalopathies; Evaluation; Glycine decarboxylase; Goals; Hour; Huntington Disease; In Vitro; Investigation; Ion Channel; Ions; Ischemia; Ischemic Stroke; Knock-out; Knockout Mice; Ligands; Link; Mediating; Mediator of activation protein; Middle Cerebral Artery Occlusion; Modeling; Molecular; Molecular Chaperones; Molecular Conformation; Multiple Sclerosis; Mus; N-Methyl-D-Aspartate Receptors; Necrosis; Nerve; Nerve Degeneration; Neurologic Deficit; Neurons; Parkinson Disease; Pathologic Processes; Pathway interactions; Patients; Peptides; Pharmaceutical Preparations; Pharmacology; Phosphorylation; Phosphotransferases; Physiological; Physiological Processes; Play; Proteins; Proteomics; Protons; RIPK3 gene; Receptor Activation; Receptor Inhibition; Receptor Serine/Threonine Kinase; Recruitment Activity; Reperfusion Therapy; Rodent; Rodent Model; Role; Serine/Threonine Phosphorylation; Spinocerebellar Ataxias; Stroke; Testing; Therapeutic; Time; Tissues; Traumatic Brain Injury; base; cell killing; clinically relevant; clinically significant; cytotoxicity; effective therapy; extracellular; in vivo; in vivo Model; interest; mouse model; nervous system disorder; neuron loss; neuroprotection; novel; novel therapeutic intervention; prevent; protective effect; protein p80; receptor; response; spinal cord and brain injury; therapeutic target; treatment strategy

PROJECT SUMMARY Tissue acidosis is a major contributing factor to neuronal cell death associated with neurological diseases, such as stroke, traumatic brain and spinal cord injuries, multiple sclerosis (MS) and amyotrophic lateral sclerosis (ALS), as well as Alzheimer's, Huntington, and Parkinson’s diseases. It has been well established that acid-sensing ion channels subtype 1a (ASIC1a) is critically involved in acidosis-induced neuronal cell death in both in vitro and in vivo models. The protective effects of ASIC1a knockout and pharmacological inhibition of ASIC1a function shown in the mouse models of ischemic stroke, MS, HD, and ALS testify the potential of targeting ASIC1a to mitigate neuronal damages in multiple types of neurological disorders. However, the mechanism(s) by which ASIC1a activation causes neuronal death remains mysterious despite extensive investigations. Conventionally, ASIC1a is believed to form cell surface cation channels activated by extracellular protons to mediate Na+ and Ca2+ entry into the cell. The ion conducting function, especially Ca2+ influx, is thought to cause Ca2+ overload that eventually leads to acid-induced cytotoxicity. However, our recent results suggest that the cell killing effect of ASIC1a is dependent not on its channel conductance, but on the recruitment and phosphorylation of serine/threonine kinase receptor interaction protein 1 (RIP1) to the C-terminus of ASIC1a protein. RIP1 is a key mediator of death receptor-induced necroptotic pathway. In rodent model of ischemic stroke, middle cerebral artery occlusion (MCAO), inhibiting RIP1, just like inhibiting ASIC1a, was shown to be neuroprotective even when the drug was administered several hours after the onset of brain ischemia. Therefore, acidosis neuronal death most likely occurs through ASIC1a-RIP1 physical coupling and the consequent activation of RIP1-dependent necroptosis. The goal of the proposed project is to elucidate this novel mechanism of acid-induced, ASIC1a/RIP1-mediated necroptotic cell demise in neurons. Aim I will define the death pathway mediated by ASIC1a-RIP1 interaction in response to acidosis through systematic evaluation of key factors involved in ASIC1a-mediated cell demise in cultured neurons and in the mouse MCAO model. Aim II will examine a novel mechanism by which a chaperone protein facilitates RIP1 activation through disruption of an intramolecular interaction between the cytoplasmic N- and C-termini of ASIC1a. Aim III will elucidate how the C-terminal RIP1 interaction domain of ASIC1a triggers and mediates acidosis-induced necroptosis and test whether disrupting such interaction can mitigate neuronal damage caused by acidosis and brain ischemia. Successful completion of this project will provide a better understanding of the molecular mechanism of neuronal acidotoxicity, which will shed lights on new treatment strategies for several major types of neurological disorders.

项目摘要 组织酸中毒是导致与神经系统疾病相关的神经元细胞死亡的主要因素， 例如中风，脑外伤和脊髓损伤，多发性硬化症（MS）和肌萎缩性侧面 硬化症（ALS）以及阿尔茨海默氏症，亨廷顿和帕金森氏病。它已经建立了 酸性离子通道亚型1a（ASIC1A）与酸中毒诱导的神经元细胞有关 体外和体内模型的死亡。 ASIC1A敲除和药理的受保护作用 缺血性卒中，MS，HD和ALS的小鼠模型中显示的ASIC1A功能的抑制作用证明了 靶向ASIC1A减轻多种神经系统疾病中神经元损害的潜力。 但是，ASIC1A激活导致神经元死亡的机制仍然是神秘的目的地 广泛的投资。通常，ASIC1A被认为会形成被激活的细胞表面阳离子通道 通过细胞外质子介导Na+和Ca2+进入细胞。离子传导功能，特别是 Ca2+影响被认为会导致Ca2+过载，有时会导致酸诱导的细胞毒性。但是，我们的 最近的结果表明，ASIC1A的细胞杀死效应不是取决于其通道电导，而是取决于 关于丝氨酸/苏氨酸激酶受体相互作用蛋白1（RIP1）的募集和磷酸化 ASIC1A蛋白的C末端。 RIP1是死亡受体诱导的坏死途径的关键介体。在 缺血性中风的啮齿动物模型，中大脑动脉闭塞（MCAO），抑制RIP1，就像抑制 ASIC1A，即使在药物后几个小时服用药物，也证明是神经保护 脑缺血的发作。因此，酸中毒神经元死亡很可能是通过ASIC1A-RIP1发生的 物理耦合和随之而来的RIP1依赖性坏死的激活。提议的目标 项目是为了阐明酸诱导的ASIC1A/RIP1介导的坏死细胞灭局的新机制 在神经元中。目的，我将定义ASIC1A-RIP1相互作用介导的死亡途径，以响应酸中毒 通过系统评估培养神经元中ASIC1A介导的细胞衰减中涉及的关键因素 在鼠标MCAO模型中。 AIM II将检查一种新型机制，链酮蛋白 通过破坏细胞质N-和 ASIC1A的C-末端。 AIM III将阐明ASIC1A的C端RIP1相互作用域如何触发 并介导酸中毒诱导的坏死作用并测试是否破坏这种相互作用可以减轻 由酸中毒和脑缺血引起的神经元损害。该项目的成功完成将提供 更好地理解神经元酸毒性的分子机制，该机制将在新的 几种主要类型的神经系统疾病的治疗策略。