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 组织酸中毒是与神经系统疾病相关的神经元细胞死亡的主要促成因素， 例如中风、创伤性脑和脊髓损伤、多发性硬化症（MS）和肌萎缩侧索硬化症 硬化症（ALS），以及阿尔茨海默病、亨廷顿病和帕金森病。这是公认的 酸敏感离子通道亚型1a（ASIC 1a）在酸中毒诱导的神经元细胞中起重要作用， 在体外和体内模型中死亡。ASIC 1a基因敲除和药理学作用的保护作用 在缺血性中风、MS、HD和ALS的小鼠模型中显示的ASIC 1a功能的抑制证实了 靶向ASIC 1a以减轻多种类型神经系统疾病中的神经元损伤的潜力。 然而，ASIC 1a激活导致神经元死亡的机制仍然是神秘的， 广泛的调查。通常认为，ASIC 1a形成细胞表面阳离子通道被激活 通过细胞外质子介导Na+和Ca 2+进入细胞。离子传导功能，特别是 Ca 2+内流被认为会导致Ca 2+过载，最终导致酸诱导的细胞毒性。但我们的 最近的研究结果表明，ASIC 1a的细胞杀伤作用不依赖于其通道电导， 对丝氨酸/苏氨酸激酶受体相互作用蛋白1（RIP 1）的募集和磷酸化的影响 ASIC 1a蛋白的C-末端。RIP 1是死亡受体诱导的坏死性凋亡途径的关键介质。在 缺血性中风的啮齿动物模型，大脑中动脉闭塞（MCAO），抑制RIP 1，就像抑制 ASIC 1a被证明是神经保护性的，即使是在注射后几小时给药。 脑缺血发作。因此，酸中毒神经元死亡最可能通过ASIC 1a-RIP 1发生 物理耦合和随后的RIP 1依赖性坏死性凋亡的激活。建议的目标 本项目旨在阐明酸诱导的ASIC 1a/RIP 1介导的坏死性凋亡细胞死亡的新机制 在神经元中。目的阐明ASIC 1a-RIP 1相互作用介导的酸中毒死亡途径 通过系统评估培养神经元中ASIC 1a介导的细胞死亡的关键因素， 在小鼠MCAO模型中。目的二将研究一种新的机制， 通过破坏细胞质N-和N-之间的分子内相互作用促进RIP 1活化。 ASIC 1a的C末端。目的III将阐明ASIC 1a的C-末端RIP 1相互作用结构域如何触发 并介导酸中毒诱导的坏死性凋亡，并测试破坏这种相互作用是否可以减轻 酸中毒和脑缺血引起的神经元损伤。该项目的成功完成将提供一个 更好地了解神经元酸毒性的分子机制，这将揭示新的 几种主要类型的神经系统疾病的治疗策略。