MOLECULAR MECHANISMS OF CELL DEATH IN PD MITOCHONDRIA

PD 线粒体细胞死亡的分子机制

• 批准号: 6618257
• 负责人: JAMES PEPPER BENNETT
• 金额: $ 23.19万
• 依托单位: UNIVERSITY OF VIRGINIA
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-08-01 至 2003-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6618257
• 关键词: Parkinson's disease; apoptosis; cell line; clinical research; disease /disorder etiology; disease /disorder model; electron transport; gene expression; human genetic material tag; human tissue; hybrid cells; membrane potentials; mitochondrial DNA; mitochondrial membrane; mitogen activated protein kinase; molecular pathology; neuropathology; oxidative stress; postmortem; protooncogene; respiratory enzyme

Idiopathic Parkinson's disease (PD) afflicts about 1 million Americans, causes widespread suffering in the individuals, and exacts a significant economic toll on society from its production on progressive motor disability. PD symptoms arise from the premature and accelerated death of substantia nigra dopamine neurons and are commonly treated with drugs that replace dopamine synaptic function in the nigrostriatal pathway. However, no available symptomatic drugs have been shown to reduce disease progression by slowing the death of dopamine neurons in humans. Studies performed mainly by the defect in mitochondrial genes coding for complex I of the electron transport chain is responsible for increased oxidative stress, detrimental changes in intracellular calcium signaling, altered mitochondrial replication and movement, and increased susceptibility to cell death mediated by mitochondrial dysfunction. This Project is the third laboratory-based study in a four Project application for a Parkinson's Research Center of Excellence. This Project will explore the molecular mechanisms of cell death produced by PD mitochondria whose genetic functions are isolated and amplified in the cytoplasmic hybrid (cybrid) cell model developed and extensively studied by this group. Results in PD cybrids will be compared to a pharmacological model of chronic complex I impairment produced by rotenone. Four Specific Aims will be examined that test interrelated hypotheses. First, the regulation of mitochondrial membrane potential will be studied with respect to the how cyclical mitochondrial depolarization-repolarization, first described in neural cells by the PI's laboratory, is altered in PD. Second, the effects of over-expressing the anti-apoptotic proteins bcl-2 and bcl-XL on cyclical mitochondrial depolarization and reduced mitochondrial membrane potential in PD will be determined. Third, the molecular mechanisms connecting mitochondrial depolarization to activation of MAPKinase cascade will be defined in control and PD models. Fourth, properties of mitochondrial transition pore (MTP) complexes isolated from PD and control brain tissues will be characterized. These properties included the very recent finding from this group that human brain MTP complexes bind cytochrome c. Depolarization-induced release of cytochrome c and the influence of recombinant bcl proteins and BH region mutants will be studied in MTP-liposomes. This project interacts extensively with the other two laboratory projects and will develop model systems to define mechanisms of action for drugs that might be neuroprotective in PD.

特发性帕金森氏病(PD)困扰着大约100万美国人，在个体中造成广泛的痛苦，并因其产生的进行性运动障碍而给社会造成巨大的经济损失。帕金森病症状源于黑质多巴胺神经元的过早和加速死亡，通常用药物取代黑质纹状体通路中的多巴胺突触功能。然而，目前还没有可用的对症药物通过延缓人类多巴胺神经元的死亡来减少疾病的进展。线粒体基因编码电子传递链复合体I的缺陷主要导致氧化应激增加，细胞内钙信号发生有害变化，线粒体复制和运动改变，以及线粒体功能障碍导致的细胞死亡的易感性增加。这个项目是帕金森卓越研究中心四个项目申请中的第三个基于实验室的研究。本项目将探索PD线粒体产生的细胞死亡的分子机制，其遗传功能是在该小组开发和广泛研究的细胞质杂交(Cybrid)细胞模型中被分离和放大的。帕金森病患者的结果将与鱼藤酮引起的慢性复合体I损伤的药理学模型进行比较。四个具体的目标将被检验，以检验相互关联的假设。首先，线粒体膜电位的调节将从周期性线粒体去极化-复极化是如何改变的方面进行研究，这种周期性去极化-复极化首先是由PI的实验室在神经细胞中描述的，在帕金森病中。其次，将确定过表达抗凋亡蛋白bcl2和bclxl对帕金森病患者线粒体周期性去极化和线粒体膜电位降低的影响。第三，将在对照和PD模型中定义将线粒体去极化与MAPKinase级联激活联系起来的分子机制。第四，将对从帕金森病患者和对照脑组织分离的线粒体转换孔(MTP)复合体的性质进行表征。这些特性包括该小组的最新发现，即人脑MTP复合体与细胞色素c结合。去极化诱导细胞色素c的释放以及重组bc1蛋白和BH区突变对MTP脂质体的影响将被研究。该项目与其他两个实验室项目广泛互动，并将开发模型系统，以确定可能对帕金森病具有神经保护作用的药物的作用机制。