MOLECULAR MECHANISMS OF MPTP NEUROTOXICITY

MPTP 神经毒性的分子机制

• 批准号: 6205079
• 负责人: Ted M. Dawson
• 金额: $ 22.93万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-09-01 至 2000-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6205079
• 关键词: Parkinson's disease; adenosine triphosphate; animal genetic material tag; corpus striatum; cysteine endopeptidases; enzyme activity; gene induction /repression; genetically modified animals; laboratory mouse; methylphenyltetrahydropyridine; molecular cloning; neurogenetics; neurotoxicology; nicotinamide adenine dinucleotide; nitric oxide; nitrites; oxidative stress; substantia nigra; superoxides; tissue /cell culture

MPTP (1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine) is used extensively in various mammalian species to produce an experimental model of Parkinson's disease (PD), a common and disabling neurodegenerative disorder of unknown cause. A variety of markers and indices in PD patents and animal models indicate involvement of oxygen free radicals and oxidative stress in the pathogenesis of PD. Preliminary studies indicate a potential pivotal role for nitric oxide in the pathogenesis of MPTP neurotoxicity and that this neurotoxicity may be mediated, in part, through the reaction of NO with the superoxide anion to form peroxynitrate. NO, or peroxynitrate, can activate amongst other responses, poly (ADP-ribose) polymerase (PARP), which may lead to the loss of cellular NAD+ and ATP, resulting in acute cell injury and death. These events may be crucial in both short-and long- term deleterious effects of MPTP. However, it is unclear whether this pathway (PARP activation and NAD+ loss) caused by these toxic effects is solely responsible for cell death, or whether other pathways such as caspase activations, which involves cleavage of PARP and other substrates may also contribute to neuronal injury. Accordingly, experiments are proposed to further clarify the role of NO in MPTP neurotoxicity and to investigate the source of superoxide anion generation and the downstream targets of NO, superoxide anion and peroxynitrate in MPTP neurotoxicity. In Specific Aim #1 we will determine the role and source of nitric oxide in MPTP-induced dopaminergic cell death. In Specific Aim #2 we will determine the role of cytosolic versus mitochondrial superoxide anion generation in MPTP-induced dopaminergic cell death. In Specific Aim #3 we will determine and clarify the role of poly (ADP-ribose) polymerase (PARP) activation and cleavage in MPTP-induced dopaminergic cell death. In Specific Aim #4 we will identify dynamically regulated genes in the rodent MPTP model of PD. Potential oxidative post-translational modification of critical enzymes and proteins that regulate the disposition of dopamine in the nigrostriatal pathway [e.g., tyrosine hydroxylase (TH), dopamine transporter (DAT) and the monoamine vesicular transporter (VMAT)] will be examined following MPTP intoxication as well. Oxidative damage, potentially through mitochondrial defects, excess or aberrant NO generation and/or monoamine metabolism has been implicated in the pathogenesis of PD. Clarification and understanding the molecular mechanisms by which oxidants induce neuronal damage, interact with PARP and caspase activation cascade and modify gene regulation, may provide novel therapeutics and targets to prevent the toxic effects of MPTP and the degenerative process of PD.

MPTP（1-甲基-4-苯基1,2,3,6-四氢吡啶）广泛使用 各种哺乳动物物种生产帕金森氏症的实验模型 疾病（PD），一种常见且残疾的神经退行性疾病 原因。 PD专利和动物模型中的各种标记和指数 表明氧气自由基和氧化应激参与 Pd的发病机理。初步研究表明潜在的关键作用 用于MPTP神经毒性发病机理中的一氧化氮 神经毒性可以部分通过NO的反应介导 超氧化阴离子形成过氧硝酸盐。不，或过氧硝酸盐，可以 激活其他响应，聚（ADP-核糖）聚合酶（PARP），， 这可能导致细胞NAD+和ATP的丧失，导致急性 细胞损伤和死亡。这些事件在短时间内可能至关重要 MPTP的术语有害影响。但是，目前尚不清楚这是否 这些毒性作用引起的途径（PARP激活和NAD+损失）为 仅负责细胞死亡，或其他途径（例如 caspase激活，涉及PARP和其他底物的裂解 也可能导致神经元损伤。因此，实验是 提议进一步阐明NO在MPTP神经毒性中的作用和 研究超氧化阴离子产生的来源和下游 MPTP神经毒性中的NO，超氧化阴离子和过氧硝酸盐的靶标。 在特定的目标＃1中，我们将确定一氧化氮的作用和来源 在MPTP诱导的多巴胺能细胞死亡中。在特定的目标＃2中，我们将 确定胞质与线粒体超氧阴离子的作用 在MPTP诱导的多巴胺能细胞死亡中产生。在特定的目标＃3中我们 将确定并阐明聚（ADP-核糖）聚合酶（PARP）的作用 MPTP诱导的多巴胺能细胞死亡中的激活和裂解。在 特定目的＃4我们将确定啮齿动物中动态调节的基因 PD的MPTP模型。潜在的氧化后翻译后修饰 临界酶和蛋白质调节多巴胺在 黑质纹状体途径[例如酪氨酸羟化酶（Th），多巴胺 转运蛋白（DAT）和单胺囊泡转运蛋白（VMAT）]为 也检查了MPTP中毒后的检查。 氧化损伤，可能通过线粒体缺陷，过量或 异常没有一代和/或单胺代谢与 PD的发病机理。澄清和理解分子 氧化剂诱导神经元损伤，与PARP相互作用的机制 和caspase激活级联和修改基因调节，可能会提供 新的治疗剂和靶标，以防止MPTP和 PD的退化过程。