Regulation of Proteasome Function in Cardiomyopathies

心肌病中蛋白酶体功能的调节

• 批准号: 8123276
• 负责人: Sharlene M Day
• 金额: $ 38.54万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-17 至 2014-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8123276
• 关键词: Acute; Adrenergic Agents; Adult; Alkaline Phosphatase; Applications Grants; Autophagocytosis; Biological Process; Cardiac; Cardiac Myocytes; Cardiomyopathies; Cell Line; Cessation of life; Chronic; Clinical; Coupled; Cyclic AMP-Dependent Protein Kinases; Data; Degradation Pathway; Development; Dilated Cardiomyopathy; Disease; Disease Progression; Disease model; Electrophoresis; Equilibrium; Etiology; Functional disorder; Gene Expression; Gene Transfer; Genes; Global Change; Goals; Health; Heart; Heart Diseases; Heart failure; Human; In Situ; In Vitro; Inherited; Isoproterenol; Laboratories; Link; Malignant Neoplasms; Measures; Mind; Modeling; Modification; Mus; Muscular Atrophy; Myocardial Infarction; Myocardial dysfunction; Myocardium; Myopathy; Neurodegenerative Disorders; Oxidative Phosphorylation; Pathway interactions; Phosphorylation; Physiologic pulse; Play; Post-Translational Protein Processing; Process; Protein Dephosphorylation; Proteins; Proteolysis; Proteomics; Public Health; Rattus; Regulation; Reporting; Role; Sampling; Sarcomeres; Skeletal Muscle; Staging; Stressful Event; System; Techniques; Therapeutic Intervention; Troponin; Troponin I; Ubiquitin; abstracting; adrenergic; comparative; gel electrophoresis; in vivo; insight; mouse model; multicatalytic endopeptidase complex; mutant; oxidation; premature; protein activation; protein aggregation; protein degradation; protein expression; protein misfolding; research study

DESCRIPTION (provided by applicant): Project abstract Proteolytic degradation is a critical process for maintaining a dynamic equilibrium of proteins and destroying damaged or misfolded proteins. As the major pathway for intracellular protein degradation, the ubiquitin proteasome system (UPS) requires precise regulation to sustain most biological processes and any perturbation in its function may have deleterious consequences. Excessive activation of the UPS has been causally linked to cancer and skeletal muscle atrophy, whereas UPS inhibition is responsible for protein aggregation in neurodegenerative diseases. Previous studies have reported proteasome dysfunction in a number of cardiac disease models, but mechanisms are largely unknown, and causality has not yet been established. This proposal uniquely focuses on the role of the UPS in cardiomyopathies, progressive and often fatal heart muscle diseases. Preliminary data from my laboratory indicate that UPS function is markedly impaired in human hypertrophic (HCM) and end-stage, dilated (DCM) cardiomyopathies, but activated in a mouse model of DCM. Drawing parallels to other diseases, it is reasonable to propose that either activation or inhibition of UPS activity in the heart could be detrimental. The unifying hypothesis put forth in this application is that dysregulation of proteolytic degradation contributes significantly to the pathophysiology of cardiomyopathies and their progression to heart failure. A precise understanding of the mechanisms responsible for proteasome dysfunction in cardiomyopathies will be critical for establishing an etiologic link to disease progression and for development of new specific therapies targeting defective proteolysis. This proposal will therefore explore potential independent, but not mutually exclusive, mechanisms of proteasome dysregulation. Aim 1 will examine post-translational mechanisms for UPS dysfunction in human cardiomyopathies, specifically phosphorylation and oxidative modifications to the proteasome using proteomics techniques. Potential consequences of proteasome dysfunction will also be studied, including protein aggregation and activation of autophagic proteolytic pathways. Aim 2 will focus on changes in proteasome phosphorylation in two mouse models - dilated cardiomyopathy induced by myocardial infarction and chronic isoproterenol administration. The goal of Aim 3 is to determine whether HCM-linked sarcomere mutant gene expression is sufficient to directly impair UPS function in adult rat cardiac myocytes in vitro, and to what extent mutant protein stability plays a role in this effect. Results from the proposed experiments are expected to provide valuable insights into potential mechanisms for dysfunctional proteolytic degradation in a broad range of cardiomyopathies and identify new targets for therapeutic intervention. PUBLIC HEALTH RELEVANCE: Cardiac muscle diseases called cardiomyopathies are the principal cause of heart failure and premature death, and are thus a major public health problem in need of considerable scientific and clinical advancement. However, large gaps in our understanding of how cardiomyopathies progress after an initial stressful event (e.g. inherited gene change, heart attack) hinder the development of effective new therapies. This grant application studies how defective mechanisms for elimination of damaged proteins in the heart contribute to cardiomyopathies, with the long term goal of identifying specific targets for new treatments for these devastating diseases.

描述（由申请人提供）：项目摘要蛋白水解降解是维持蛋白质动态平衡和破坏受损或错误折叠蛋白质的关键过程。作为细胞内蛋白质降解的主要途径，泛素蛋白酶体系统 (UPS) 需要精确调节才能维持大多数生物过程，其功能的任何扰动都可能产生有害后果。 UPS 的过度激活与癌症和骨骼肌萎缩有因果关系，而 UPS 的抑制则导致神经退行性疾病中的蛋白质聚集。先前的研究报道了许多心脏病模型中的蛋白酶体功能障碍，但其机制很大程度上尚不清楚，因果关系尚未确定。该提案特别关注 UPS 在心肌病、进行性且往往致命的心肌疾病中的作用。我实验室的初步数据表明，UPS 功能在人类肥厚型 (HCM) 和终末期扩张型 (DCM) 心肌病中明显受损，但在 DCM 小鼠模型中被激活。与其他疾病相似，我们有理由认为激活或抑制心脏中的 UPS 活动可能是有害的。本申请中提出的统一假设是，蛋白水解降解的失调对心肌病的病理生理学及其进展为心力衰竭有显着影响。准确了解心肌病中蛋白酶体功能障碍的机制对于建立与疾病进展的病因学联系以及开发针对缺陷蛋白水解的新特异性疗法至关重要。因此，该提案将探索潜在的独立但不相互排斥的蛋白酶体失调机制。目标 1 将研究人类心肌病中 UPS 功能障碍的翻译后机制，特别是使用蛋白质组学技术对蛋白酶体进行磷酸化和氧化修饰。还将研究蛋白酶体功能障碍的潜在后果，包括蛋白质聚集和自噬蛋白水解途径的激活。目标 2 将重点关注两种小鼠模型中蛋白酶体磷酸化的变化 - 心肌梗塞引起的扩张型心肌病和长期服用异丙肾上腺素。目标 3 的目标是确定 HCM 相关肌节突变基因表达是否足以在体外直接损害成年大鼠心肌细胞的 UPS 功能，以及突变蛋白稳定性在多大程度上在这种效应中发挥作用。所提出的实验结果预计将为广泛的心肌病中功能失调的蛋白水解降解的潜在机制提供有价值的见解，并确定治疗干预的新靶标。公共卫生相关性：称为心肌病的心肌疾病是心力衰竭和过早死亡的主要原因，因此是需要大量科学和临床进步的主要公共卫生问题。然而，我们对心肌病在最初的应激事件（例如遗传基因改变、心脏病发作）后如何进展的理解存在巨大差距，阻碍了有效新疗法的开发。该拨款申请研究了消除心脏中受损蛋白质的缺陷机制​​如何导致心肌病，其长期目标是确定针对这些破坏性疾病的新疗法的具体靶标。