The role of Parkin in selective dopamine neuronal degeneration

Parkin在选择性多巴胺神经元变性中的作用

基本信息

批准号：
8457023
负责人：
JOHN L GOUDREAU
金额：
$ 27.79万
依托单位：
MICHIGAN STATE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2010
资助国家：
美国
起止时间：
2010-05-15 至 2015-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8457023
关键词：
Acute Address Affect Animal Model Autophagosome Cell Death Cell Survival Chronic Complex Data Dopamine Dose Equilibrium Event Exposure to Goals Homeostasis Hypothalamic structure In Vitro Injury Knock-out Knockout Mice Link Mediating Mediator of activation protein Messenger RNA Metabolism Methods Midbrain structure Mitochondria Modeling Molecular Morphology Motor Mus Nerve Degeneration Neurodegenerative Disorders Neuronal Injury Neurons Neurotoxins Nonpenetrating Wounds Parkinson Disease Pattern Phenotype Play Population Predisposition Process Proteasome Inhibition Protein Biosynthesis Proteins RNA Interference Recombinant adeno-associated virus (rAAV)Recovery Resistance Risk Role Stress Symptoms Time TimeLine Toxic effect Translating Up-Regulation Wild Type Mouse disability dopaminergic neuron in vivo in vivo Model inhibitor/antagonist mitochondrial dysfunction motor impairment multicatalytic endopeptidase complex neuronal survival neurotoxic neurotoxicity novel overexpression oxidative damage parkin gene/protein parkin protein prevent protein degradation protein expression protein misfolding public health relevance research study response stressor synuclein therapy development ubiquitin-protein ligase

项目摘要

DESCRIPTION (provided by applicant): Progressive degeneration of nigrostriatal (NS) dopamine (DA) neurons underlies the motor symptoms of Parkinson's disease (PD) and therapies that slow progression are lacking. Abnormal DA metabolism has been proposed as a mechanism for the selective degeneration of NSDA neurons. All DA neurons, however, are not affected to the same extent in PD. While there is severe loss of midbrain NSDA neurons, the hypothalamic tuberoinfundibular (TI) DA neurons remain intact. A similar pattern of susceptibility can be seen in these DA neuronal populations when they are exposed to mitochondrial complex I inhibitors in vitro and in vivo. Although NSDA and TIDA neurons have a similar initial response to complex I inhibition, only TIDA neurons are able to recover using a mechanism that is dependent on new protein synthesis. Our preliminary data also implicate that parkin is involved in this differential susceptibility since it is markedly upregulated in TIDA, but not NSDA neurons following an acute toxic injury. Parkin is a multifunctional protein that supports normal mitochondrial function, has an E3 ligase that tags misfolded proteins for proteosomal degradation and appears to protect DA neurons from a variety of toxic insults. Parkin also has important proteosome independent functions that could promote DA neuronal survival. The overall goal of this project is to elucidate the parkin-mediated molecular mechanisms that render NSDA neurons sensitive and TIDA neurons resistant to exogenous neurotoxin exposure. We hypothesize that parkin, acting primarily via proteosome-independent mechanisms, protects TIDA neurons and can rescue NSDA neurons from injury induced by a PD relevant pathological stress, mitochondrial complex I inhibition. To address the central hypothesis, rAAV-mediated, spatially restricted manipulation of parkin expression will be performed in wild-type mice and on mice with a parkin null background. The impact of exogenously modulating parkin expression on the TIDA and NSDA neuronal responses to both acute and chronic neurotoxic stress will be assessed to confirm the central role of parkin in allowing DA neurons to recover following an initial insult. Molecular and pharmacological methods will be used to elucidate the initial downstream mediators of the neuroprotective effects of parkin. Despite the observation that a significant portion of DA neurons have been lost at the onset of clinically observable symptoms of PD, it is plausible that there are neurons that are at risk and dysfunctional, but that could recover if provided the necessary machinery for recovery. Since TIDA neurons are unique amongst DA neurons in their ability to recover from an injury induced by a PD relevant pathological stressor, they provide a powerful platform to dissect the parkin-mediated mechanisms of DA neuronal recovery and could yield novel targets for neuroprotective therapy development.

描述（由申请人提供）：黑质纹状体（NS）多巴胺（DA）神经元的进行性变性是帕金森病（PD）运动症状的基础，并且缺乏减缓进展的治疗方法。异常的 DA 代谢已被认为是 NSDA 神经元选择性变性的机制。然而，所有 DA 神经元在 PD 中受到的影响程度并不相同。虽然中脑 NSDA 神经元严重缺失，但下丘脑结节漏斗部 (TI) DA 神经元保持完整。当这些 DA 神经元群体在体外和体内暴露于线粒体复合物 I 抑制剂时，可以看到类似的易感性模式。尽管 NSDA 和 TIDA 神经元对复合物 I 抑制具有相似的初始反应，但只有 TIDA 神经元能够使用依赖于新蛋白质合成的机制进行恢复。我们的初步数据还表明，parkin 参与了这种不同的易感性，因为在急性毒性损伤后，parkin 在 TIDA 神经元中显着上调，但在 NSDA 神经元中则不然。 Parkin 是一种支持正常线粒体功能的多功能蛋白，具有 E3 连接酶，可以标记错误折叠的蛋白以进行蛋白体降解，并且似乎可以保护 DA 神经元免受各种毒性损伤。 Parkin 还具有重要的独立于蛋白酶体的功能，可以促进 DA 神经元的存活。该项目的总体目标是阐明 Parkin 介导的分子机制，使 NSDA 神经元敏感，而 TIDA 神经元对外源性神经毒素暴露具有抵抗力。我们假设 Parkin 主要通过不依赖于蛋白酶体的机制发挥作用，保护 TIDA 神经元，并可以拯救 NSDA 神经元免受 PD 相关病理应激、线粒体复合物 I 抑制引起的损伤。为了解决中心假设，将在野生型小鼠和具有parkin无效背景的小鼠中进行rAAV介导的、空间受限的parkin表达操作。将评估外源调节 Parkin 表达对 TIDA 和 NSDA 神经元对急性和慢性神经毒性应激反应的影响，以确认 Parkin 在允许 DA 神经元在初始损伤后恢复中的核心作用。将使用分子和药理学方法来阐明parkin神经保护作用的初始下游介质。尽管观察到很大一部分 DA 神经元在出现临床可观察到的 PD 症状时已经丢失，但有可能存在处于危险和功能障碍的神经元，但如果提供必要的恢复机制，这些神经元可能会恢复。由于 TIDA 神经元在 DA 神经元中具有从 PD 相关病理应激源引起的损伤中恢复的能力，因此它们提供了一个强大的平台来剖析 Parkin 介导的 DA 神经元恢复机制，并可能产生神经保护治疗开发的新靶点。