Mitochondrial control of neuronal excitotoxicity

神经元兴奋性毒性的线粒体控制

基本信息

批准号：
6916383
负责人：
David Nicholls
金额：
$ 36.86万
依托单位：
BUCK INSTITUTE FOR RESEARCH ON AGING
依托单位国家：
美国
项目类别：
财政年份：
2001
资助国家：
美国
起止时间：
2001-07-15 至 2007-06-30
项目状态：
已结题

项目摘要

DESCRIPTION (Provided by the Applicant): In the USA stroke kills 155,000 people per annum and is the third largest cause of death, after diseases of the heart and cancer. Furthermore 4,000,000 stroke survivors in the USA alone are coping with its debilitating effects. Stroke rates rise sharply with age, thus the increasing aging population will further increase its incidence. There is a brief window of opportunity in the hours following stroke during which the damage to the brain can be kept to a minimum, but the design of rational therapy would be facilitated if we had greater understanding of the underlying processes. Neuronal damage following stroke is amplified by the pathological release of glutamate (excitotoxicity), the consequent chronic activation of NMDA selective glutamate receptors and the influx of calcium into the cell. Mitochondrial calcium loading and consequent dysfunction is implicated not only in stroke but also in chronic neurodegenerative disorders such as Parkinson's and Huntington's diseases. The long term goal of this study is therefore to develop a comprehensive understanding of the acute and chronic consequences for the mitochondrion and neuron of pathological NMDA receptor activation, to use this information to devise and test neuroprotective strategies for the brief therapeutic window following stroke, and to relate these findings to the slow neurodegenerative disorders in which mitochondrial dysfunction is implicated. Mitochondria generate ATP, but also detoxify reactive oxygen species produced by the respiratory chain, control the cellular redox state and regulate cytoplasmic Ca2+. Any combination of these pathways may dysfunction in these disorders and the challenge is to unravel their complex interactions to identify primary lesions and suggest therapeutic and preventative strategies. The hypothesis that this application will test is that changes in mitochondrial bioenergetics function initiated during brief glutamate exposure continue even in the absence of receptor activation and are responsible for the delayed death of the neuron. To test this hypothesis we propose studies with the following specific aims. 1. To establish the immediate and delayed bioenergetics consequences of transient pathological NMDA receptor activation for cultured cerebellar granule neurons and their in situ mitochondria. While the granule cell in vivo is relatively resistant to excitotoxicity, the extensive existing information on the bioenergetics properties of these cells, coupled with their tolerance to a range of mitochondrial inhibitors makes the preparation suitable to establish principles applicable to neurons in general. 2. To establish the mechanism by which the initial transient exposure to glutamate initiates the subsequent mitochondrial dysfunction. 3. To test hypotheses that the lethality of glutamate in this model can be affected by controlling membrane potential and respiratory chain capacity. 4. To test the hypothesis that mitochondria at specific intracellular locations may be selectively vulnerable to glutamate excitotoxicity because of their proximity to NMDA receptors, or their location in regions of high-energy demand.

描述（由申请人提供）：在美国，中风导致 155,000 人死亡每年，是继心脏病之后的第三大死因和癌症。此外，仅在美国就有 4,000,000 名中风幸存者正在应对及其使人衰弱的影响。中风发生率随着年龄的增长而急剧上升，因此人口老龄化的加剧将进一步增加其发病率。有一个中风后数小时内的短暂机会窗口，在此期间对大脑的伤害可以保持在最低限度，但合理的设计如果我们对潜在的问题有更深入的了解，治疗就会变得更加容易。流程。中风后的神经元损伤会因病理原因而放大谷氨酸的释放（兴奋性毒性），随之而来的慢性激活 NMDA 选择性谷氨酸受体和钙流入细胞。线粒体钙负荷和随之而来的功能障碍不仅涉及不仅适用于中风，还适用于帕金森氏症等慢性神经退行性疾病和亨廷顿氏舞蹈病。因此，本研究的长期目标是全面了解急性和慢性后果病理性 NMDA 受体激活的线粒体和神经元，以使用这些信息用于设计和测试简短的神经保护策略中风后的治疗窗口，并将这些发现与缓慢的涉及线粒体功能障碍的神经退行性疾病。线粒体产生 ATP，同时也解毒产生的活性氧通过呼吸链，控制细胞氧化还原状态并调节细胞质Ca2+。这些途径的任何组合都可能导致这些途径功能障碍疾病和挑战是解开它们复杂的相互作用识别主要病变并提出治疗和预防策略。该应用程序将测试的假设是线粒体的变化在短暂的谷氨酸暴露期间启动的生物能功能甚至持续在没有受体激活的情况下并导致延迟死亡神经元的。为了检验这一假设，我们提出以下研究具体目标。 1. 建立即时和延迟生物能学短暂病理性 NMDA 受体激活对培养细胞的影响小脑颗粒神经元及其原位线粒体。而颗粒体内细胞对兴奋性毒性相对抵抗，广泛存在有关这些细胞的生物能学特性的信息，以及它们的对一系列线粒体抑制剂的耐受性使得该制剂适合建立适用于一般神经元的原则。 2. 建立最初短暂接触谷氨酸启动的机制随后线粒体功能障碍。 3. 检验致死率的假设该模型中谷氨酸的含量可以通过控制膜电位来影响和呼吸链能力。 4. 检验线粒体位于特定的细胞内位置可能选择性地容易受到谷氨酸的影响由于靠近 NMDA 受体或其位置而产生兴奋性毒性在能源需求高的地区。