Role of mitochondria in neurodegenerative diseases

线粒体在神经退行性疾病中的作用

基本信息

批准号：
9563160
负责人：
Richard James Youle
金额：
$ 112.91万
依托单位：
NATIONAL INSTITUTE OF NEUROLOGICAL DISORDERS AND STROKE
依托单位国家：
美国
项目类别：
财政年份：
资助国家：
美国
起止时间：
至
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/9563160
关键词：
ATP phosphohydrolase Alpha Cell Animal Model Autophagocytosis Autophagosome Cells Cellular biology Cytosol Excision Genes Guanosine Triphosphate Phosphohydrolases Impairment Mammalian Cell Mediating Membrane Mitochondria Mitochondrial DNA Mitochondrial Diseases Mitochondrial Proteins Modeling Molecular Mus Mutate Mutation Neurodegenerative Disorders Neurons Organelles Outer Mitochondrial Membrane PINK1 gene PTEN-induced putative kinase PTGS1 gene Parkinson Disease Pathway interactions Patients Peptide Hydrolases Phosphotransferases Process Quality Control RNA interference screen Recruitment Activity Role Signal Transduction Testing Therapeutic Ubiquitin Work base fly gene product in vivo mitochondrial DNA mutation multicatalytic endopeptidase complex neuroprotection parkin gene/protein prevent screening selective expression sensor small molecule libraries ubiquitin-protein ligase

项目摘要

We have explored the role of mitochondria in Parkinson's disease (PD). At least two gene products mutated in familial PD, PINK1 and Parkin, are now known to mediate autophagic removal of defective mitochondria suggesting that one cause of PD is an impairment of mitochondrial quality control. PINK1 is a kinase located on mitochondria whereas Parkin is an E3 ubiquitin ligase normally located in the cytosol. Upon mitochondrial damage Pink1 recruits cytosolic Parkin to mitochondria to mediate mitophagy revealing a cell biology pathway in mammalian cells where Pink1 works upstream of Parkin. We have found that PINK1 is rapidly turned over in cells. In healthy mitochondria PINK1 is constitutively imported into the inner membrane and degraded by the protease PARL, and maintained at very low levels. When mitochondria sustain damage PINK1 import and degradation is prevented allowing its accumulation on the outer mitochondrial membrane. Thus PINK1 acts as a sensor of mitochondria function. When PINK1 accumulates on the outer mitochondrial membrane of damaged organelles it recruits Parkin to mitochondria from the cytosol. Parkin recruitment requires PINK1 kinase activity but the substrate of PINK1 involved in this process remains unknown. Once on the mitochondria, Parkin ubiquitinates mitochondrial proteins including the GTPases Mfn1 and 2. The loss of ubiqutinated Mfn1 and 2 by proteosomal degradation prevents damaged mitochondria from fusing with healthy mitochondria thereby segregating them fordisposal. The ubiquitin chains Parkin forms on other mitochondrial proteins appear to signal the elimination of mitochondria by autophagy. We found that the proteosome and the AAA ATPase, p97/VCP, Optineurin or NDP52 and ATG5 are required for Parkin mediated mitophagy further indicating the importance of ubiquitin in Parkin mediated mitophagy. Corroborating this model we have found that in cybrid cells that contain a mixture of functional mitochondria with wild type mitochondrial DNA and dysfunctional mitochondria with a mutation in mitochondrial DNA in the COX1 gene, increasing Parkin expression selectively eliminates the damaged mitochondria and enriches for the propagation of wild type mitochondrial DNA. Based on these results we predict that stimulation of the PINK1/Parkin pathway may facilitate mitochondrial quality control and may be of potential therapeutic benefit for patients with mitochondrial diseases and certain forms of Parkinson's disease. An animal model that accumulates mitochondrial DNA mutations corroborates the model that Parkin mediates quality control and rescues neurons of damaged mitochondria. We have begun screening chemical libraries to identify agents that stimulate PINK1 expression and Parkin translocation. We have also completed RNAi screens to identify gene products participating in PINK1 recruitment of Parkin to mitochondria and Parkin stimulation of autophagosome engulfment of mitochondria.

我们已经探索了线粒体在帕金森氏病（PD）中的作用。现在众所周知，在家族性PD，PINK1和PARKIN中突变的至少两个基因产物可以介导自噬去除有缺陷的线粒体，这表明PD的一个原因是线粒体质量控制的损害。 Pink1是一种位于线粒体上的激酶，而帕金是通常位于细胞质中的E3泛素连接酶。线粒体损伤后，pink1募集了细胞质帕金到线粒体，以介导线粒体，揭示了pink1在帕金上游的哺乳动物细胞中的细胞生物学途径。我们发现PINK1在细胞中迅速翻转。在健康的线粒体中，pink1由组成型进口到内膜，并被蛋白酶parl降解，并保持非常低的水平。当线粒体维持损伤时，防止PINK1进口和降解，使其在外部线粒体膜上积聚。因此，PINK1充当线粒体功能的传感器。当Pink1积聚在受损细胞器的外部线粒体膜上时，它会从细胞质中募集帕金到线粒体。 Parkin招募需要PINK1激酶活性，但参与此过程的PINK1的底物仍然未知。 Once on the mitochondria, Parkin ubiquitinates mitochondrial proteins including the GTPases Mfn1 and 2. The loss of ubiqutinated Mfn1 and 2 by proteosomal degradation prevents damaged mitochondria from fusing with healthy mitochondria thereby segregating them fordisposal.其他线粒体蛋白上的泛素链条形成parkin形式，似乎表明通过自噬消除了线粒体。我们发现，蛋白质体和AAA ATPase，P97/VCP，Optineurin或NDP52和ATG5是Parkin介导的线粒体所必需的，这进一步表明了泛素在Parkin介导的线粒体中的重要性。佐证该模型我们发现，在含有功能性线粒体与野生型线粒体DNA和功能障碍的线粒体中的混合物中，在Cox1基因中的线粒体DNA突变，在Parkin表达中，在线粒体DNA中具有突变，从而选择性地消除了损坏的线粒体和富集型野生型菌群的损坏的线粒体表达。基于这些结果，我们预测刺激PINK1/Parkin途径可能有助于线粒体质量控制，并且可能对线粒体疾病和某些形式的帕金森氏病的患者具有潜在的治疗益处。累积线粒体DNA突变的动物模型证实了帕金介导质量控制并营救神经元受损的线粒体的模型。我们已经开始筛选化学文库，以识别刺激Pink1表达和帕克蛋白易位的药物。我们还完成了RNAi屏幕，以鉴定参与PINK1 PARKIN募集到线粒体和Parkin刺激线粒体吞噬的基因产品。