Mitochondrial Protein Misfolding and Aggregation after Hypoxia: Mechanisms and Mitigation

缺氧后线粒体蛋白错误折叠和聚集：机制和缓解

• 批准号: 9401407
• 负责人: C. Michael Crowder
• 金额: $ 51.49万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-07-15 至 2022-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9401407
• 关键词: Affect; Animals; Apoptosis; Biological; Biological Assay; Brain Hypoxia-Ischemia; Caenorhabditis elegans; Calcium; Cause of Death; Cell Death; Cell Death Process; Cell Survival; Cells; Cessation of life; Chemicals; Collaborations; Cytoplasm; Data; Disease; Disease model; Endoplasmic Reticulum; Functional disorder; Genetic; Genetic Screening; Goals; Hippocampus (Brain); Hypoxia; Injury; Kinetics; Lead; Mammalian Cell; Mediating; Middle Cerebral Artery Occlusion; Mind; Mitochondria; Mitochondrial Proteins; Modeling; Mus; Myocardial Infarction; Necrosis; Nematoda; Neurology; Neurons; Organism; Oxygen; Pathology; Pharmacology; Phenotype; Potential Energy; Probability; Proteins; Proteomics; Publications; Publishing; Reperfusion Therapy; Reporter; Reporting; Research; Resistance; Speed; Stress; Stroke; Testing; Universities; Washington; cell injury; cell type; cost; disability; effective therapy; genetic inducer; human disease; improved; injured; misfolded protein; mitochondrial dysfunction; mortality; mouse model; mutant; novel; protein aggregation; protein misfolding; proteostasis; response; small molecule; stroke treatment; tool

Project Summary Hypoxia and reoxygenation create havoc in cells. This havoc if unrepaired will ultimately lead to cell dysfunction and death in diseases such as myocardial infarction and stroke, the number one causes of death and disability in the US. Unfortunately, no effective therapy for hypoxic injury, short of restoring oxygenation, has been approved, suggesting that an unrecognized aspect of hypoxic injury is not being effectively treated by previous strategies. Mitochondria have long been recognized as central to hypoxic injury. Mitochondria are the primary utilizer of oxygen in cells, converting oxygen to the chemical potential energy required for the survival of cells and the organism. Mitochondria also are central to cell death processes – in particular apoptosis and forms of calcium-mediated death including necrosis. Both necrosis and apoptosis are thought to be the most prevalent mechanisms of death after hypoxic injury. However, a full understanding of how hypoxia injures mitochondria leading to cell death is lacking. We have recently reported a novel type of hypoxia- induced mitochondrial pathology – mitochondrial protein misfolding. Our published data show that mitochondrial protein misfolding occurs early in the hypoxic injury cascade, prior to any evidence of cell death. This suggests the hypothesis that mitochondrial protein misfolding may be both a consequence of hypoxia and a cause of hypoxic cell injury and death. Consistent with this hypothesis, genetic or pharmacologic manipulations in the nematode C. elegans that activate the mitochondrial unfolded protein response (mitoUPR), an intracellular homeostatic response to mitochondrial misfolded proteins, protects from hypoxic injury and improves animal survival. Since this publication, we have developed new fluorescent mitochondrial protein reporter tools in C. elegans in order to study protein misfolding directly and have preliminary evidence that mitochondrial proteins not only misfold but aggregate after hypoxia. The goals of this project are to develop a fundamental understanding of hypoxia-induced mitochondrial protein misfolding and aggregation, to identify ways to mitigate disruption of mitochondrial proteostasis, and to determine if similar disruption can be detected and mitigated in mouse models of human disease. Our general strategy is to take advantage of the speed, low cost, and specialized cell biological tools of C. elegans for fundamental discovery and to apply where possible our discoveries to mammalian models of hypoxic disease. Our specific aims are as follows: Aim 1. Determine the identity of the misfolded and aggregated mitochondrial proteins and the kinetics, determinants, and consequences of aggregation. Aim 2. Identify genetic and pharmacological manipulations that ameliorate mitochondrial protein misfolding in C. elegans. Aim 3. Determine whether mitochondrial protein misfolding/aggregation occur in mouse models of disease. Completion of these aims will increase our understanding of a novel hypoxic pathology of the mitochondria and will potentially identify ways to mitigate it.

项目摘要 缺氧和复氧会对细胞造成严重破坏。这种破坏如果得不到修复， 功能障碍和死亡的疾病，如心肌梗死和中风，头号死因 残疾人在美国。不幸的是，没有有效的治疗缺氧损伤，恢复氧合， 已经被批准，这表明缺氧损伤的一个未被认识的方面没有得到有效治疗， 以前的战略。线粒体长期以来被认为是缺氧损伤的中心。线粒体是 细胞中氧气的主要利用者，将氧气转化为所需的化学势能， 细胞和生物体的生存。线粒体也是细胞死亡过程的核心， 细胞凋亡和钙介导的死亡形式，包括坏死。坏死和凋亡都被认为是 是缺氧损伤后最常见的死亡机制。然而，充分了解缺氧 导致细胞死亡的线粒体损伤缺乏。我们最近报道了一种新型的缺氧- 诱导线粒体病理-线粒体蛋白质错误折叠。我们公布的数据显示， 线粒体蛋白质错误折叠发生在缺氧损伤级联反应的早期，在任何细胞死亡的证据之前。 这表明线粒体蛋白质错误折叠可能是缺氧的结果， 缺氧细胞损伤和死亡的原因。与这一假设一致，遗传或药理学 操纵线虫C.激活线粒体未折叠蛋白反应的线虫 （mitoUPR），一种对线粒体错误折叠蛋白的细胞内稳态反应， 提高动物生存率。自从这篇文章发表以来，我们已经开发了新的荧光线粒体， 蛋白质报告工具在C.为了直接研究蛋白质的错误折叠， 线粒体蛋白质在缺氧后不仅错误折叠而且聚集。该项目的目标是 发展对缺氧诱导的线粒体蛋白质错误折叠的基本理解， 聚集，以确定减轻线粒体蛋白质稳态破坏的方法，并确定是否 在人类疾病的小鼠模型中可以检测和减轻类似的破坏。我们的一般 战略是利用C.优雅的， 这是一个基本的发现，并在可能的情况下将我们的发现应用于缺氧疾病的哺乳动物模型。 我们的具体目标如下：目标1。确定错误折叠和聚集的线粒体 蛋白质和动力学，决定因素和聚集的后果。目标2.识别基因和 药理学操作，改善线粒体蛋白质错误折叠在C。优雅的目标3. 确定线粒体蛋白质错误折叠/聚集是否发生在小鼠疾病模型中。 这些目标的完成将增加我们对线粒体缺氧病理学的理解 并可能找到缓解的方法。