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：
10688932
负责人：
Richard James Youle
金额：
$ 171.83万
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/10688932
关键词：
Age Animal Model Autophagocytosis Autophagosome Biological Cells Cellular biology Collaborations Cytosol DNA Defect Drosophila melanogaster Excision Genetic Screening German population Golgi Apparatus Idiopathic Parkinson Disease Immune signaling Immunity Impairment Inflammation Inflammatory Interferon Type I Knock-out Link Lipids Locomotion Mammalian Cell Mediating Membrane Mitochondria Mitochondrial DNA Modeling Molecular Morphology Motor Mus Muscle Mutate Mutation NF-kappa B Natural Immunity Neurodegenerative Disorders Neurons PINK1 gene Parkin Parkinson Disease Pathology Pathway interactions Patients Penetrance Persons Phenotype Phosphotransferases Posture Quality Control RNA interference screen Role Signal Transduction Testing Wing Work aged cohort cytokine dopaminergic neuron fly gene product in vivo innate immune function loss of function man mitochondrial DNA mutation mutant neuroprotection novel prevent recruit response sensor small molecule libraries ubiquitin-protein ligase whole genome

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. PINK1 acts as a sensor of mitochondria function and Parkin induced the elimination of those damaged mitochondria. An animal model that accumulates mitochondrial DNA mutations corroborates the model that Parkin mediates quality control and rescues neurons from damaged mitochondria. We preformed full genome RNAi screens to identify gene products participating in PINK1 recruitment of Parkin to mitochondria and Parkin stimulation of autophagosome engulfment of mitochondria. 1) The genetic screens led us to identify a strong inflammatory phenotype in both Parkin-/- and PINK1-/- mice when crossed with Mutator mice, which accumulate mitochondrial DNA mutations with age. This inflammation is completely rescued by concurrent loss of STING, a central regulator of the type I Interferon response to cytosolic DNA. The loss of DA neurons from the SNc and the motor defect observed in aged Parkin-/-; Mutator mice are also rescued by loss of STING, suggesting that inflammation facilitates this phenotype. In collaboration with a leading German group with large cohorts of PINK1 and Parkin mutant PD patients we discovered that people with biallelic Parkin mutations also display elevated circulating cytokines at levels higher than either healthy controls or those with idiopathic PD. Furthermore, these biallelic Parkin and PINK1 patients had higher circulating levels of mitochondrial DNA than either healthy controls or idiopathic PD patients. These results support the model that PINK1- and Parkin-mediated mitophagy restrains innate immunity as a way to prevent PD. 2) In contrast to mice and man, recessive mutations in Parkin in Drosophila melanogaster display severe physical and locomotion defects caused by excess mitochondria damage, leading to muscle defects and progressive degeneration of dopaminergic neurons. Innate immunity pathways including STING and NF-kB pathways are conserved in flies, however, the role of innate immune signaling in Pink1/Parkin mutant fly pathology has not been established. We found the conserved immunity regulator STING mediates the Parkin loss of function phenotypes. Two genetically independent STING and Parkin double knockout strains were generated. Deletion of STING with significantly reduces the penetrance of the major Parkin null fly phenotypes including flight muscle defects, wing posture, and climbing ability. Surprisingly, the underlying mitochondria morphology defects in Parkin mutant flies were also suppressed in these double mutant lines. 3) We explored how STING, functioning downstream of mitochondrial damage and mtDNA release into the cytosol, activates innate immunity. We discovered a new and unanticipated function of STING in activating the lipidation of LC3, which is classically thought to be linked to double membrane autophagosomes. Instead of inducing autophagy as had been the dominant model, we found STING lipidates LC3 onto single membrane Golgi associated membranes. The innate immune function of this novel step in STING activity is being explored by us and others.

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。 PINK1充当线粒体功能的传感器，而Parkin诱导了消除那些损坏的线粒体。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从损坏的线粒体中拯救神经元的模型。我们预先建立了完整的基因组RNAi筛查，以鉴定参与PINK1 PARKIN募集到线粒体的PINK1和Parkin刺激线粒体吞噬的基因产物。 1）遗传筛选使我们在与突变体小鼠交叉时，在帕金蛋白 - / - / - 和pink1 - / - 小鼠中鉴定出强烈的炎症表型，该突变型小鼠会累积随着年龄的增长的线粒体DNA突变。这种炎症是通过同时发生sting的损失（I型干扰素对胞质DNA反应的中心调节剂）完全挽救的。在老年帕金（Parkin）中观察到的SNC和运动缺陷的DA神经元的丧失 - / - ;突变器小鼠还通过损失刺激而救出，这表明炎症促进了这种表型。通过与大量的PINK1和Parkin突变PD患者共同的德国人群合作，我们发现患有双重性帕克蛋白突变的人在高于健康对照或特发性PD的水平上还显示出循环的细胞因子升高。此外，这些双乳蛋白和PINK1患者的线粒体DNA水平高于健康对照或特发性PD患者。这些结果支持了PINK1和PARKIN介导的线粒体限制先天免疫的模型，以防止PD。 2）与小鼠和人相反，果蝇中帕金的隐性突变表现出严重的身体和运动缺陷，这是由于线粒体过多损害引起的，导致肌肉缺陷和多巴胺能神经元的逐渐变性。先天免疫途径在内，包括刺痛和NF-KB途径在苍蝇中是保守的，但是，尚未确定先天免疫信号传导在Pink1/Parkin突变蝇病理学中的作用。我们发现保守的免疫调节剂刺激介导了功能表型的帕金损失。产生了两个独立的遗传性刺痛和帕金双基因敲除菌株。用刺的删除大大降低了主要的帕金无效表型的渗透率，包括飞行肌肉缺陷，翼姿势和攀爬能力。令人惊讶的是，在这些双重突变线中，帕金突变蝇中的潜在线粒体形态缺陷也被抑制。 3）我们探索了刺痛，线粒体损伤下游的作用和mtDNA释放到细胞质中如何激活先天的免疫力。我们在激活LC3的脂质中发现了一种新的且意外的功能，该功能通常被认为与双膜自噬体相关。我们没有像主要模型那样诱导自噬，而是发现脂肪在单膜高尔基体上刺激了脂质。我们和其他人正在探索这一新颖的刺激活动步骤的先天免疫功能。