Targeting pathologic intracellular calcium release to prevent lethal arrhythmias

靶向病理性细胞内钙释放以预防致命性心律失常

• 批准号: 10677136
• 负责人: Aaron Gochman
• 金额: $ 3.53万
• 依托单位: VANDERBILT UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-06-01 至 2026-05-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10677136
• 关键词: Address; Anti-Arrhythmia Agents; Arrhythmia; Binding; Biological Assay; Calcium; Calcium Oscillations; Calcium-Sensing Receptors; Cardiac; Cardiac Myocytes; Catecholaminergic Polymorphic Ventricular Tachycardia; Cell membrane; Cells; Chronic; Closure by clamp; Collaborations; Complement; Congestive Heart Failure; Coupling; Data; Development; Diastole; Docking; Drug Kinetics; Drug Targeting; Electrophysiology (science); Failure; Flecainide; Future; Genetic; Heart; Heart Atrium; Heart Diseases; Hyperactivity; Image; In Vitro; Ion Channel; Libraries; Measurement; Measures; Mechanics; Mediating; Membrane; Membrane Potentials; Mentors; Modeling; Morbidity - disease rate; Mus; Muscle Contraction; Mutation; Myocardial Contraction; Myocardial Infarction; Outcome; Pathologic; Patient risk; Patients; Permeability; Pharmaceutical Preparations; Phosphorylation; Physiological; Post-Translational Protein Processing; Process; Property; Receptor Inhibition; Research; Risk; Risk Reduction; Ryanodine Receptor Calcium Release Channel; Sarcoplasmic Reticulum; Signal Transduction; Sodium; Syndrome; Synthesis Chemistry; Systole; Testing; Therapeutic; Treatment Efficacy; United States; Ventricular Arrhythmia; analog; drug candidate; embolic stroke; high risk; in silico; inhibitor; lead candidate; mortality; mouse model; novel therapeutics; oxidation; patch clamp; patient population; preclinical study; prevent; structural heart disease; sudden cardiac death; therapeutic candidate; therapeutic evaluation; tool; voltage; voltage sensitive dye

PROJECT SUMMARY/ABSTRACT RyR2 is an intracellular calcium (Ca) release channel expressed in the sarcoplasmic reticulum (SR) of cardiomyocytes. In the normal heart, RyR2 Ca release from the SR is tightly regulated and only occurs during systole to facilitate heart contraction. In heart disease, RyR2 Ca release can occur during diastole and is considered pathologic. Pathologic Ca release can be caused by RyR2 mutations or RyR2 post-translational modifications. Pathologic Ca release during diastole reduces cardiac contractility due to depletion of SR Ca stores and is pro-arrhythmogenic due to delayed after-depolarizations resulting from sodium (Na) flux into the cell via the Na-Ca exchanger. RyR2 mutations cause catecholaminergic polymorphic ventricular tachycardia (CPVT), a genetic arrhythmia syndrome, while post-translational modifications have been widely documented in congestive heart failure (CHF) caused by myocardial infarction. Both conditions are associated with a high risk of sudden cardiac death (SCD). My mentor discovered that an old antiarrhythmic drug – flecainide – prevents pathologic rather than physiologic Ca release and is strikingly effective in preventing ventricular arrhythmias in CPVT patients. Importantly, he recently discovered that flecainide’s efficacy depends not on Na channel block but rather RyR2 block. Unfortunately, due to its Na channel blocking properties, flecainide increases mortality in patients with CHF and cannot be used in this patient population. To address these patients’ risk for SCD – currently unmitigated by available drugs – I aim to develop a flecainide analogue that maintains RyR2 block but not Na channel block. In doing so, I will investigate the mechanism of action of flecainide and test the hypothesis that its efficacy depends on a change in the membrane potential across the SR. My research background and the established use of patch clamp electrophysiology and calcium imaging in my mentor’s lab will enable me to test flecainide analogues generated by our collaborators in synthetic chemistry. To probe the mechanism of action underlying flecainide’s voltage-dependent RyR2 block, I will employ a variety of tools including genetically encoded voltage indicators and voltage-sensitive dyes to capture the theoretical membrane potential change that occurs at the SR. The results from this aim will not only clarify flecainide’s mechanism of action but also yield a novel therapeutic principle – that voltage-dependent block of RyR2 channels is a key feature for the development of future RyR2 inhibitors as antiarrhythmic drugs.

项目总结/摘要 RyR 2是一种细胞内钙（Ca）释放通道，在肌浆网（SR）中表达， 心肌细胞在正常心脏中，SR中RyR 2 Ca的释放受到严格调节，并且仅在心肌缺血时发生。 收缩以促进心脏收缩。在心脏病中，RyR 2 Ca释放可发生在脑卒中期间， 被认为是病态的病理性钙释放可由RyR 2突变或RyR 2翻译后突变引起。 修改.由于SR Ca耗竭，在心肌缺血期间病理性Ca释放降低心肌收缩力 由于钠（Na）流入脑内导致延迟后去极化， 细胞通过钠钙交换器。RyR 2基因突变导致儿茶酚胺能多形性室性心动过速 （CPVT），一种遗传性心律失常综合征，而翻译后修饰已被广泛记录 心肌梗死引起的充血性心力衰竭（CHF）。这两种情况都与高 心源性猝死（SCD）。我的导师发现一种古老的抗抑郁药-氟卡尼- 预防病理性而非生理性钙释放，并显著有效地预防心室 CPVT患者的心律失常。重要的是，他最近发现氟卡尼的疗效不依赖于钠， 通道阻滞，而不是RyR 2阻滞。不幸的是，由于氟卡尼的Na通道阻断特性， 增加CHF患者的死亡率，不能用于该患者人群。解决这些 患者的SCD风险-目前可用药物无法减轻-我的目标是开发一种氟卡尼类似物， 维持RyR 2阻断，但不维持Na通道阻断。在这样做的时候，我将调查的行动机制， 氟卡尼和测试的假设，其疗效取决于跨膜电位的变化， Sr.我的研究背景以及膜片钳电生理学和钙成像在 我导师的实验室将使我能够测试我们的合作者在合成中产生的氟卡尼类似物 化学.为了探索氟卡尼电压依赖性RyR 2阻滞的作用机制，我将 使用各种工具，包括遗传编码的电压指示剂和电压敏感染料， 发生在SR的理论膜电位变化。这一目标的结果不仅将澄清 氟卡尼作用机制，而且产生了一种新的治疗原理-电压依赖性 RyR 2通道的阻断是开发未来RyR 2抑制剂的关键特征， 抗抑郁药