The mechanism of cardio-protection from a sulfonylurea receptor isoform 2 splice variant (SUR2A-55) and its role in regulating ROMK activity, the putative mitochondrial ATP sensitive potassium channel

磺酰脲受体亚型 2 剪接变体 (SUR2A-55) 的心脏保护机制及其在调节 ROMK 活性（假定的线粒体 ATP 敏感钾通道）中的作用

• 批准号: 10514603
• 负责人: Mohun Ramratnam
• 金额: --
• 依托单位: WM S. MIDDLETON MEMORIAL VETERANS HOSP
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-10-01 至 2025-09-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10514603
• 关键词: ATP sensitive potassium channel complex; Acute myocardial infarction; Cardiac; Cardiac Myocytes; Cardiology; Cardiomyopathies; Cell Survival; Clinic; Clinical; Collaborations; Core Facility; Coupled; Cytoplasm; Data; Dedications; Development; Electron Transport; Environment; Equipment; Fatty Acids; Fellowship; Fostering; Foundations; Funding; Generations; Genetic; Glucose; Glycolysis; Goals; Heart; Heart failure; Herbicides; Hospitals; Human; Injury; Inner mitochondrial membrane; Institution; Internal Medicine; Intervention; Ischemia; Ischemic Preconditioning; Kidney; Knock-out; Knockout Mice; Knowledge; Laboratories; Mass Spectrum Analysis; Mechanics; Medicine; Mentors; Mentorship; Metabolic; Metabolism; Mitochondria; Modeling; Molecular; Molecular Structure; Morbidity - disease rate; Mus; Myocardial; Myocardial Infarction; Myocardial Ischemia; Myocardial Reperfusion Injury; Neonatal; Organelles; Outcome; Pathway interactions; Patients; Physicians; Potassium Channel; Process; Protein Isoforms; Proteomics; Public Health; RNA Splicing; Reperfusion Injury; Reperfusion Therapy; Reporting; Research; Research Project Grants; Residencies; Resistance; Resources; Respiration; Rest; Risk; Risk Factors; Role; Scientist; Services; Signal Transduction; Societies; Sulfonylurea Compounds; Syndrome; System; Testing; Time; Training; Transgenic Organisms; Universities; Variant; Veterans; Veterans Health Administration; Wisconsin; Work; atherosclerosis risk; cardioprotection; career; career development; clinical practice; combat; cost; educational atmosphere; experience; fatty acid metabolism; fatty acid oxidation; glucose metabolism; heart function; heart metabolism; improved; induced pluripotent stem cell derived cardiomyocytes; inherited cardiomyopathy; interest; ischemic injury; knock-down; loss of function; medical schools; mitochondrial metabolism; mitochondrial permeability transition pore; mortality; mouse model; new therapeutic target; novel; novel therapeutics; overexpression; pharmacologic; preference; preservation; prevent; professor; programs; protein protein interaction; recruit; response; skills; sulfonylurea receptor; targeted treatment; translational therapeutics

Candidate: I am a staff cardiologist at the William S. Middleton Memorial VA and Assistant Professor of Medicine at the University of Wisconsin School of Medicine and Public Health. I obtained my MD from Northwestern University and completed internal medicine residency at Johns Hopkins Hospital and cardiology fellowship at the University of Pittsburgh. During my fellowship training I dedicated additional time in the laboratory of Dr. Ferhaan Ahmad to study mechanisms of genetic cardiomyopathies, which eventually led to the study of cardioprotective mechanisms in ischemia reperfusion injury due to my clinical interest in interventional cardiology. I was recruited to the William S. Middleton Memorial VA and University of Wisconsin to provide increased interventional cardiology coverage to Veteran patients but to also continue my work in cardioprotection with start-up funds, institutional mentorship and laboratory resources. Research Project: Activation of mitochondrial K+ flux confers cardioprotection in models of ischemic injury. Of the potential channels that modulate K+ flux, the putative mitochondrial ATP-sensitive potassium channel (mitoKATP) is most closely related to cardioprotection. However the molecular identity of mitoKATP is unknown and represents a critical gap in knowledge to discover therapies that target the mitochondrial K+ cycle. Prior studies and my preliminary data provide evidence for a short 55 kDa splice variant of the sulfonylurea receptor 2A (SUR2A-55) that targets mitochondria, regulates mitoKATP activity, enables increased glucose metabolism and protects the heart from ischemia-reperfusion injury when overexpressed. In addition, prior studies and my preliminary data suggest a role for the renal outer medullary K+ channel (ROMK) in mitochondrial ATP sensitive K+ transport and cardioprotection. In this proposal we hypothesize that SUR2A-55 combines with ROMK2 to form a cardiac mitoKATP channel that blocks ischemic injury by activating the mitochondrial K+ cycle and enhancing glucose metabolism. By targeting both mitochondria and myocardial substrate utilization, SUR2A-55 represents a novel target in the treatment of ischemic heart disease. We propose to investigate this hypothesis with three specific aims. Specific Aim 1: Determine if SUR2A-55 associates with ROMK in cardiac mitochondria to form a mitochondrial K+ channel. Immuno-affinity enrichment coupled with mass spectroscopy will be used to examine potential associations between SUR2A-55 and ROMK2. Specific Aim 2: Determine if the loss of function of cardiac ROMK prevents activation of mitoKATP and cardioprotection. We will test whether pharmacologic inhibition or genetic knockdown of ROMK prevents activation of mitoKATP and protection from ischemic preconditioning. Specific Aim 3: Examine how TGSUR2A-55 mice utilize metabolic substrates and whether a preference for glucose utilization over fatty acids during ischemia contributes to cardioprotection. Glucose and fatty acid metabolism from isolated hanging hearts during rest and after ischemia will be assessed in TGSUR2A-55 and WT mice. Career Plan: My long-term career goal is to become an independently funded VA physician-scientist who is a leader in the field of treating ischemic heart disease by targeting cardiac mitochondria and metabolism. My primary VA research mentor, Dr. Nihal Ahmad, will guide my progress and training. My additional mentors and collaborators will provide training to accomplish my research aims and career goals. The results from this VA CDA will provide me with the preliminary data and research experience to formulate a competitive MERIT Review proposal to further develop novel therapeutic targets for ischemic heart disease. Environment: I will complete the proposed research at the VA and the University of Wisconsin. Both organizations provide an exceptionally collegial atmosphere and strong institutional support that include laboratory resources, equipment, and core facilities.

候选人：我是弗吉尼亚州威廉·S·米德尔顿纪念医院的心脏病专家兼医学助理教授 在威斯康星大学医学与公共卫生学院。我从西北大学获得了医学博士学位 大学并在约翰·霍普金斯医院完成了内科住院医师培训，并在以下医院完成了心脏病学研究金 匹兹堡大学。在我的进修培训期间，我在 Dr. 的实验室投入了额外的时间。 Ferhaan Ahmad 致力于研究遗传性心肌病的机制，最终导致了 由于我对介入治疗的临床兴趣，我研究了缺血再灌注损伤的心脏保护机制 心脏病学。我被招募到威廉·米德尔顿纪念馆和威斯康星大学提供 增加了对退伍军人患者的介入心脏病学覆盖范围，同时也继续我在心脏保护方面的工作 拥有启动资金、机构指导和实验室资源。 研究项目：线粒体 K+ 通量的激活可在缺血性损伤模型中提供心脏保护作用。的 调节 K+ 通量的潜在通道，假定的线粒体 ATP 敏感钾通道 (mitoKATP) 与心脏保护关系最为密切。然而 mitoKATP 的分子身份尚不清楚，并且 代表了发现针对线粒体 K+ 循环的疗法的关键知识空白。先前的研究 我的初步数据为磺酰脲受体 2A 的短 55 kDa 剪接变体提供了证据 (SUR2A-55) 靶向线粒体，调节 mitoKATP 活性，促进葡萄糖代谢和 过度表达时可保护心脏免受缺血再灌注损伤。此外，之前的研究和我的 初步数据表明肾外髓 K+ 通道 (ROMK) 在线粒体 ATP 敏感中发挥作用 K+ 运输和心脏保护。在此提案中，我们假设 SUR2A-55 与 ROMK2 结合以 形成心脏 mitoKATP 通道，通过激活线粒体 K+ 循环来阻止缺血性损伤 并增强葡萄糖代谢。通过靶向线粒体和心肌底物利用， SUR2A-55 代表了治疗缺血性心脏病的新靶点。我们建议对此进行调查 具有三个具体目标的假设。具体目标 1：确定 SUR2A-55 是否与心脏疾病中的 ROMK 相关 线粒体形成线粒体 K+ 通道。免疫亲和富集与质谱联用 将用于检查 SUR2A-55 和 ROMK2 之间的潜在关联。具体目标 2：确定是否 心脏ROMK功能的丧失会阻止mitoKATP的激活和心脏保护。我们将测试是否 ROMK 的药理学抑制或基因敲除可防止 mitoKATP 的激活并防止 缺血预处理。具体目标 3：检查 TGSUR2A-55 小鼠如何利用代谢底物并 缺血期间对葡萄糖的利用优于脂肪酸是否有助于心脏保护。 将评估休息期间和缺血后离体悬吊心脏的葡萄糖和脂肪酸代谢 在 TGSUR2A-55 和 WT 小鼠中。 职业规划：我的长期职业目标是成为一名独立资助的退伍军人事务部医师科学家 通过靶向心脏线粒体和代谢来治疗缺血性心脏病领域的领导者。我的 退伍军人管理局的主要研究导师 Nihal Ahmad 博士将指导我的进步和培训。我的额外导师和 合作者将提供培训以实现我的研究目标和职业目标。本次 VA 的结果 CDA 将为我提供初步数据和研究经验，以制定有竞争力的 MERIT 审查 建议进一步开发缺血性心脏病的新治疗靶点。 环境：我将在退伍军人管理局和威斯康星大学完成拟议的研究。两个都 组织提供了非凡的合作氛围和强有力的机构支持，其中包括 实验室资源、设备和核心设施。