Role of Protein Import in the Development of the Diabetic Heart

蛋白质进口在糖尿病心脏发育中的作用

• 批准号: 10635641
• 负责人: John M Hollander
• 金额: $ 54.41万
• 依托单位: WEST VIRGINIA UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-04-01 至 2027-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10635641
• 关键词: Address; Architecture; Biological Assay; Cardiac; Cardiovascular system; Cessation of life; Development; Diabetes Mellitus; Disease; Evaluation; Functional disorder; Genome; Health Care Costs; Heart; Heart failure; Human; Impairment; Incidence; Inner mitochondrial membrane; Knowledge; Life; Location; Maintenance; Mission; Mitochondria; Mitochondrial Matrix; Mitochondrial Proteins; Modeling; Molecular; Molecular Conformation; Motor; Mus; Myocardial dysfunction; Non-Insulin-Dependent Diabetes Mellitus; Nuclear; Nuclear Import; Nuclear Proteins; Outcome; Outer Mitochondrial Membrane; Pathway interactions; Patients; Peptide Hydrolases; Performance; Process; Prognosis; Protein Import; Proteins; Proteomics; Public Health; Research; Role; Set protein; Site; Stress; Structure; Testing; Therapeutic Intervention; Type 2 diabetic; United States National Institutes of Health; Work; biological adaptation to stress; burden of illness; db/db mouse; diabetes pathogenesis; diabetic; diabetic patient; experimental study; insight; mitochondrial dysfunction; mitochondrial heat shock protein 70; mouse model; novel; overexpression; preventive intervention; protein aggregation; proteostasis; therapeutic development

PROJECT SUMMARY Cardiovascular complications account for the majority of deaths in diabetic patients. Mitochondrial dysfunction is central to the disease and it precipitates contractile impairment, leading to death. However, the precise mechanisms that cause mitochondrial dysfunction in the diabetic heart remain unclear. Using type 2 diabetic human (patient) and mouse (db/db) models, we observed pronounced disruption to mitochondrial structure and function, which were associated with the loss of mitochondrial proteins. The vast majority of mitochondrial proteins are nuclear genome-encoded and require import into the mitochondrion. Import occurs through a coordinated set of machinery containing an active motor, driven by mitochondrial heat shock protein 70 (mtHsp70). We observed decreased mtHsp70 content in cardiac mitochondria from type 2 diabetic patients and db/db mice, and a decrease in mitochondrial protein import. Following import, mitochondrial proteins are refolded into native structures to become functional. MtHsp70 also participates in the refolding process, and works synergistically with Lon Peptidase 1, Mitochondrial (LonP1), an AAA+ protease of the mitochondrial matrix. We have also observed a decrease in LonP1 in the type 2 diabetic heart. When mitochondrial protein import is not functioning properly, aggregated nuclear genome-encoded proteins accumulate on the exterior of the mitochondrion leading to a phenomenon termed mitochondrial precursor over-accumulation stress. Currently, it is unclear what factors contribute to a decrease in protein import efficiency and refolding or whether manipulation of these processes can restore mitochondrial proteomic make-up, mitochondrial function and cardiac contractile performance in the diabetic heart. Our proposed studies address this critical gap in knowledge. The information will enhance our understanding of these processes and aid in the development of therapeutic strategies that target specific import constituents that contribute to loss of mitochondrial proteins. The central hypothesis to be tested is that decreased protein import and refolding in the type 2 diabetic heart causes loss of mitochondrial proteins and mitochondrial precursor over-accumulation stress leading to mitochondrial dysfunction and contractile impairment. The objectives of this application are to (1) identify submitochondrial locations where protein import is compromised in type 2 diabetic mitochondria and the impact on import machinery; (2) evaluate the impact of type 2 diabetes mellitus on mitochondrial protein refolding and the synergistic influence of mtHsp70 and LonP1; and (3) determine the extent of mitochondrial and proteomic stress that occurs in the type 2 diabetic heart, due to failed mitochondrial protein import contributing to mitochondrial precursor over-accumulation stress. Completion of these studies is expected to provide fundamental molecular insight into the mechanisms contributing to the loss of nuclear genome-encoded mitochondrial proteins in the type 2 diabetic heart and the cellular consequences leading to mitochondrial and cardiac dysfunction.

项目摘要 心血管并发症占糖尿病患者的大部分死亡。线粒体功能障碍 是该疾病的核心，它会造成收缩障碍，导致死亡。但是，确切的 引起线粒体功能障碍的糖尿病心脏的机制尚不清楚。使用2型糖尿病 人（患者）和小鼠（DB/dB）模型，我们观察到对线粒体结构和 功能，与线粒体蛋白的丧失有关。绝大多数线粒体 蛋白质是核基因组编码的，需要进口到线粒体中。导入是通过一个 由线粒体热激蛋白70驱动的有效电动机的协调组机械集 （MTHSP70）。我们观察到来自2型糖尿病患者的心脏线粒体中MTHSP70含量降低， DB/DB小鼠，线粒体蛋白进口的减少。导入后，将线粒体蛋白重新折叠 进入本地结构以变得功能。 MTHSP70还参与了重新折叠过程，并有效 与LON肽酶1，线粒体（LONP1）（线粒体基质的AAA+蛋白酶）协同作用。我们 还观察到2型糖尿病心脏中LONP1的降低。线粒体蛋白的进口不是 正常运行的是，汇总的核基因组编码蛋白积聚在 线粒体导致一种现象称为线粒体前体过度蓄积应力。目前，它 尚不清楚哪些因素导致蛋白质进口效率和重新折叠的降低或是否操纵 这些过程可以恢复线粒体蛋白质组学的化妆，线粒体功能和心脏收缩 糖尿病心脏的表现。我们提出的研究解决了知识的这一关键差距。信息 将增强我们对这些过程的理解，并有助于制定治疗策略 目标特定的进口成分，导致线粒体蛋白的丧失。中心假设为 测试的是，在2型糖尿病心脏中进口和重新折叠的蛋白质减少会导致线粒体的丧失 蛋白质和线粒体前体过度蓄积应力导致线粒体功能障碍和 收缩障碍。此应用程序的目标是（1）确定clistochochondrial的位置 蛋白质导入在2型糖尿病线粒体和对进口机械的影响中受到损害； （2）评估 2型糖尿病的影响对线粒体蛋白的重新折叠和MTHSP70的协同影响 和lonp1; （3）确定在2型糖尿病中发生的线粒体和蛋白质组学应激的程度 心脏，由于线粒体蛋白的失败导致了线粒体前体过度蓄积应力。 这些研究的完成有望提供对机制的基本分子见解 有助于2型糖尿病心脏中核基因组编码的线粒体蛋白的丧失和 细胞后果导致线粒体和心脏功能障碍。