Mechanisms of age-dependent nigral neuron loss in PINK1 knockout rats

PINK1 基因敲除大鼠年龄依赖性黑质神经元丢失的机制

• 批准号: 8694365
• 负责人: Matthew S Goldberg
• 金额: $ 10.08万
• 依托单位: UT SOUTHWESTERN MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-04-01 至 2014-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8694365
• 关键词: Affect; Age; Age-Months; Animal Model; Autophagocytosis; Beds; Behavior; Behavioral; Biology; Bradykinesia; Brain; Brain region; Cell Culture Techniques; Cells; Clinical; Complex; Cultured Cells; Cytoprotection; Data; Defect; Deletion Mutation; Development; Diagnosis; Diet; Dietary intake; Disease; Disease Progression; Disease model; Drosophila genus; Elderly; Electron Transport; Event; Exhibits; Gait abnormality; Genes; Genetic; Health; Human; Immunohistochemistry; Impairment; In Vitro; Inherited; Intervention; Knock-out; Knockout Mice; Knowledge; Laboratories; Lewy Bodies; Life; Link; Mediating; Membrane; Membrane Potentials; Methylene blue; Mission; Mitochondria; Modeling; Molecular; Morphology; Motor; Movement Disorders; Mus; Mutation; Nerve Degeneration; Neurodegenerative Disorders; Outcome Measure; Outer Mitochondrial Membrane; PINK1 gene; Parkinson Disease; Parkinsonian Disorders; Pathogenesis; Phenotype; Phosphotransferases; Premature Mortality; Publishing; Rattus; Recruitment Activity; Respiratory Chain; Rest Tremor; Risk Factors; Role; Rotenone; Severities; Signal Transduction; Substantia nigra structure; Symptoms; Testing; Therapeutic; Time; Tissues; Toxin; United States National Institutes of Health; age related; alpha synuclein; animal facility; base; brain cell; brain tissue; disability; disorder risk; dopaminergic neuron; effective therapy; experience; feeding; inhibitor/antagonist; innovation; loss of function mutation; mitochondrial autophagy; mitochondrial dysfunction; mitochondrial membrane; muscle degeneration; neurochemistry; neuron loss; neuropathology; novel; overexpression; palliative; parkin gene/protein; prevent; therapeutic development

DESCRIPTION (provided by applicant): Parkinson's disease (PD) is a frequent cause of neurodegeneration, disability and premature mortality in older adults. Loss of dopaminergic neurons in the substantia nigra is the primary neuropathological hallmark of PD. There are currently no treatments proven to slow down the progressive nigral cell loss in PD, which causes increasing severity of the clinical symptoms. The recent linking of human mutations in genes such as Parkin, DJ-1, and PINK1 to recessively inherited forms of PD provides new opportunities to discover pathogenic mechanisms and to develop and test neuroprotective therapies in animal models with nigral cell loss based on mechanisms physiologically relevant to human parkinsonism. We have pursued this strategy for over a decade using knockout (KO) mice. For unknown reasons, Parkin KO, DJ-1 KO and PINK1 KO mice do not reproduce the nigral cell loss that occurs in humans bearing loss-of-function mutations in these genes. We and others identified mitochondrial dysfunction (respiratory chain defects) in KO mice, Drosophila and cultured cells, suggesting that this is a common and perhaps early event in the mechanism by which loss-of-function mutations in these genes cause nigral cell loss. However, the lack of nigral cell loss precludes using nigral cell loss as an outcome measure to directly test this and other potential key pathogenic mechanisms in Parkin KO, DJ-1 KO or PINK1 KO mice. Recently developed PINK1 KO rats show age-dependent nigral cell loss beginning at age 6 months and reaching 50% by age 7 months. The age-dependent nigral neuron loss in PINK1 KO rats makes it possible for the first time to test the leading candidate pathogenic mechanisms such as mitochondrial impairment and diminished Parkin-mediated mitochondrial autophagy directly in a mammalian brain that reproduces this central neuropathological feature of PD. We propose to use PINK1 KO rats to achieve the following interrelated specific aims which have been chosen because of their significance for therapeutic development: 1) To identify mechanisms by which PINK1 deficiency leads to nigral cell loss in the rat, 2) To characterize Parkin as an inhibitor of age-dependent nigral cell loss in PINK1 KO rats and 3) To stimulate the mitochondrial respiratory chain as a potential therapy for PD. We expect to contribute a systematic characterization of PINK1 KO rats as an apt test bed for therapeutic development by testing the principal hypothesis that PINK1 deficiency diminishes Parkin-mediated degradation of impaired mitochondria and the second main hypothesis that respiratory chain stimulation via dietary intake of methylene blue is neuroprotective in PINK1 KO rats. We have previously shown that methylene blue prevents neurodegeneration in the rotenone rat PD model. The use of this novel rat model of nigral cell loss is innovative and the proposal will significantly impact the understanding of PD by shifting emphasis to disease mechanisms present in PD brain tissue selected for their strong therapeutic potential. The knowledge gained from our study will be broadly applicable to diseases associated with mitochondrial dysfunction and neurodegeneration.

描述（由申请人提供）：帕金森氏病（PD）是老年人神经退行性，残疾和过早死亡的经常原因。黑质中多巴胺能神经元的丧失是PD的主要神经病理学标志。目前尚无治疗方法可以减慢PD的进行性ni骨细胞损失，从而导致临床症状的严重程度增加。诸如Parkin，DJ-1和Pink1等基因中的人类突变与隐性遗传遗传的PD形式的最新联系为发现致病机制的新机会，并根据与人类帕金森氏症具有生理上有关的机制的动物模型中的动物模型中的动物模型中开发和测试神经保护疗法。我们已经使用淘汰（KO）小鼠追求了这一策略。由于未知原因，Parkin KO，DJ-1 KO和Pink1 KO小鼠不会再现这些基因功能丧失突变的人类发生的nigral细胞损失。我们和其他人确定了KO小鼠，果蝇和培养的细胞中的线粒体功能障碍（呼吸链缺损），这表明这是这些基因丧失功能突变引起ni骨细胞损失的机制中常见的，也许是早期事件。然而，缺乏使用ni骨细胞损失作为直接测试Parkin KO，DJ-1 KO或Pink1 KO小鼠的这种和其他潜在的关键致病机制的结果措施的ni骨损失。最近开发的PINK1 KO大鼠显示出年龄依赖年龄的细胞损失，从6个月开始，到7个月的年龄达到50％。 PINK1 KO大鼠年龄依赖的ni元神经元丧失使得首次可以测试领先的候选病原机制，例如线粒体损伤和Parkin介导的线粒体自噬的减少，直接在哺乳动物的大脑中再现了PD的这种中心神经病理学特征。我们建议使用PINK1 KO大鼠实现以下相互关联的特定目的，因为它们对治疗性发育的重要性：1）识别pink1缺乏导致大鼠nigria损失的机制，2）将Parkin表征为Parkin作为抑制剂的抑制剂 PINK1 KO大鼠的年龄依赖性nigral细胞损失，3）刺激线粒体呼吸链作为PD的潜在疗法。我们希望通过测试主要假设，即PINK1缺乏症会减少Parkin介导的线粒体受损的降解和第二个主要假设，即通过饮食中甲基蓝蓝色是神经蛋白酶粉Pink1 ko rats的呼吸链刺激，将pink1 ko大鼠作为治疗开发的适当测试床有系统的特征。我们先前已经表明，亚甲基蓝色可防止紫藤大鼠PD模型中的神经退行性。这种新型大鼠ni骨细胞损失模型的使用是创新的，该提案将通过将重点转移到疾病机制中，从而对PD的理解产生重大影响，以供PD脑组织中存在的疾病机制，以表现其强大的治疗潜力。从我们的研究中获得的知识将广泛适用于与线粒体功能障碍和神经变性有关的疾病。