Proteostasis dysregulation and alpha-synuclein

蛋白质稳态失调和 α-突触核蛋白

• 批准号: 10620658
• 负责人: XIN QI
• 金额: $ 60.45万
• 依托单位: CASE WESTERN RESERVE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-05-01 至 2025-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10620658
• 关键词: Aging; Alzheimer' s Disease; Amyloid beta-Protein; Animal Model; Area; Attenuated; Behavioral; Binding; Biochemical; Bioenergetics; Biology; Brain; Brain region; Cell Culture Techniques; Cell Death; Cell Nucleus; Cell Survival; Cells; Cognitive; Communication; Complex; Corpus striatum structure; Cultured Cells; Defect; Defense Mechanisms; Dementia with Lewy Bodies; Disease; Event; Exposure to; Fiber; Genes; Genetic Transcription; Goals; Health; Howard Temin Award; Human; Impairment; Lewy Body Dementia; Link; Mediating; Medical; Messenger RNA; Mitochondria; Mitochondrial Matrix; Mitochondrial Proteins; Molecular; Molecular Chaperones; Monitor; Motor Activity; Mus; Nerve Degeneration; Neurodegenerative Disorders; Neuronal Injury; Neurons; Oxidative Stress Induction; Parkinson Disease; Pathogenesis; Pathologic; Patients; Peptide Hydrolases; Peptides; Play; Production; Proteins; Proteomics; Reactive Oxygen Species; Regulation; Research; Role; Signal Pathway; Signal Transduction; Stress; Substantia nigra structure; Testing; Therapeutic; Time; Toxic effect; Transgenic Mice; United States National Institutes of Health; Work; alpha synuclein; dopaminergic neuron; genetic manipulation; induced pluripotent stem cell; inhibitor; mouse model; mouse synuclein alpha; mutant; neuropathology; novel; overexpression; proteostasis; response; synucleinopathy; tau Proteins; therapy development

Accumulation of alpha-synuclein (αSyn) causes degeneration of dopaminergic (DA) and non-DA neurons in Parkinson’s disease (PD) and Dementia with Lewy Bodies (DLB). αSyn also contributes to the fibrilization of amyloid-β and tau, two key proteins in Alzheimer’s disease (AD), which suggests a key role for αSyn toxicity in neurodegeneration. Thus, it is important to elucidate downstream effects and the factors promoting the toxic conversion of αSyn, towards understanding the pathogenesis of and developing disease-modifying therapies for synucleinopathies. In PD and DLB, pathological αSyn proteins enrich in mitochondria of vulnerable brain regions, where to induce mitochondrial bioenergetic defects and production of reactive oxygen species. Despite evidence suggests that αSyn-mitochondrial interactions may play a causal role in PD and DLB, the field lacks a detailed understanding of the mechanisms by which αSyn abnormality and mitochondrial functional deficiency influence each other. To maintain normal mitochondrial health and function, cells employ a mitochondria-to-nucleus signaling pathway termed the mitochondrial unfolded protein response (UPRmt). The UPRmt monitors mitochondrial proteostasis through mitochondrial specific proteases and molecular chaperones, which facilitate folding and/or degradation of unfolded proteins within mitochondria. They also communicate with the nucleus by retrograde signaling to activate the expression of peptide-folding related proteins. The UPRmt is an important defense mechanism for maintaining the quality of proteins within the mitochondria under stress. Defects in UPRmt have been linked to aging and neurodegeneration. Our recent work showed, for the first time, that the protein level of ClpP, a mitochondrial matrix protease induced during UPRmt activation, was decreased in neurons expressing αSyn wildtype (WT) or A53T mutant, in brains of mice carrying A53T mutant, and in the Substantia Nigra of PD patients. The mRNA level of ClpP remained unchanged, suggesting a transcriptional independent effect. Preliminary study further found that the protein level of ClpP and not other mitochondrial proteases, decreased in the cortex of patients with DLB and mice expressing human Thy1-αSyn. These results suggest that a decrease in ClpP is a common event implicated in the pathogenesis of both PD and DLB. Whereas silencing ClpP in neurons increased a load of unfolded proteins in the mitochondria, reduced mitochondrial bioenergetic activity and increased cell death; overexpressing ClpP abolished αSyn-induced oxidative stress in cultured cells, and attenuated αSyn hyper-phosphorylation and behavioral abnormality in αSyn A53T mice. Notably, we found that αSyn bound to ClpP and suppressed ClpP peptidase activity, whereas genetic manipulation of ClpP influenced the assembly of non-toxic αSyn tetramers that resist aggregation. Thus, our pilot findings highlight a previously unidentified interdependence between pathological αSyn and mitochondrial protease ClpP, which results in a disturbance of mitochondrial proteostasis, leading to neuronal damage. Given that αSyn accumulation is a common pathological hallmark of both PD and DLB, the goal of this study is to determine the role of ClpP-mediated mitochondrial proteostasis in PD and DLB at both mechanistic and therapeutic level. Built on our study supported by the NIH bridge award R56 NS105632-1A1, we will test the central hypothesis that pathological αSyn disturbs mitochondrial proteostasis by suppressing ClpP and UPRmt, which impairs mitochondrial bioenergetic activity and promotes the toxic conversion of αSyn, leading to αSyn neuropathology. Our research team has the unique synergistic expertise in UPRmt, mitochondrial biology, and αSyn neuropathology required to impact this significant area of unmet medical need. Successful completion of the proposed study will not only contribute to the basic understanding of disease pathogenesis, but it will also aid in the development of treatments for PD and DLB and even other neurodegenerative diseases in which αSyn aggregation manifests.

α-核蛋白（αSyn）的积累会导致帕金森氏病（PD）（PD）和痴呆症的多巴胺能（DA）和非DA神经元的变性，并带有Lewy Bodies（DLB）。 αSyn也有助于 淀粉样蛋白-β和Tau，阿尔茨海默氏病（AD）的两个关键蛋白，这表明αsyn毒性在 神经变性。这是重要的是阐明下游效应和促进有毒的因素 αSyn的转化，以了解突触核苷的疾病疗法的发病机理。在PD和DLB中，病理αSyn蛋白富含脆弱大脑区域的线粒体，在其中诱导线粒体生物能缺陷和活性氧的产生。尽管有证据表明，αsyn-Mitochrial相互作用可能在PD和DLB中起因果作用，但该领域缺乏对αSyn绝对和线粒体功能缺乏相互影响的机制的详细理解。为了维持正常的线粒体健康和功能，细胞采用线粒体到核信号通路，称为线粒体展开的蛋白质反应（UPRMT）。 UPRMT通过线粒体特异性蛋白和分子链酮监测线粒体蛋白质的，从而促进线粒体内未折叠的蛋白质的折叠和/或降解。他们还通过逆行信号传导与核us通信，以激活脱皮相关蛋白的表达。 UPRMT是在压力下保持线粒体内蛋白质质量的重要防御机制。 UPRMT中的缺陷与衰老和神经变性有关。我们最近的工作首次表明，CLPP的蛋白水平是UPRMT激活期间诱导的线粒体基质蛋白酶，CLPP的mRNA水平保持不变，表明具有转录独立效应。初步研究进一步发现，CLPP的蛋白水平和其他线粒体蛋白在表达人Thy1-αsyn的DLB和小鼠的皮层中降低。这些结果表明，CLPP的降低是在PD和DLB的发病机理中实现的常见事件。尽管神经元中的沉默CLPP增加了线粒体中的一大堆展开的蛋白质，但 线粒体生物能活性减少并增加细胞死亡；过表达的CLPP废除了αSyn诱导的培养细胞中的氧化应激，并减弱了αSyn高磷酸化和αSynA53T小鼠的行为异常。值得注意的是，我们发现αSyn与CLPP结合并抑制了CLPP Peeldase活性，而CLPP的遗传操纵影响了抗聚集的非毒性αSyn四聚体的组装。这是我们的试点发现突出了病理性αSyn和线粒体蛋白酶CLPP之间先前未识别的相互依赖性，这导致了线粒体蛋白抑制性的灾难，从而导致神经元损伤。鉴于αSyn积累是PD和DLB的常见病理标志，这项研究的目的是确定CLPP介导的线粒体蛋白抑制在PD和DLB在机械和治疗水平上的作用。在我们的研究基于NIH Bridge Award R56 NS105632-1A1的支持下，我们将测试一个中心假设，即病理αSyn通过抑制Clpp和UPRMT干扰了线粒体蛋白质癌，而Clpp和UPRMT会损害线粒体生物量化活性，并促进αSynynyalsy的毒性转化。我们的研究团队在UPRMT，线粒体生物学和αSyn神经病理学方面具有独特的协同专业知识，以影响这一重要的医疗需求。拟议研究的成功完成不仅将有助于对疾病发病机理的基本理解，而且还将有助于开发PD和DLB的治疗，甚至其他神经退行性疾病，其中αSyn聚集体现了。