Exploring the role of ATP1A3 mutations in sudden unexplained death in epilepsy

探索 ATP1A3 突变在癫痫不明原因猝死中的作用

• 批准号: 10522820
• 负责人: Andrew P. Landstrom
• 金额: $ 71.79万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-22 至 2027-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10522820
• 关键词: 3-Dimensional; ATP1A3 gene; Action Potentials; Acute; Affinity; Agonist; Arrhythmia; Binding; Biological Models; Bradycardia; Brain; Calcium; Calcium Signaling; Cardiac; Cardiac Myocytes; Cardiovascular Physiology; Catalytic Domain; Cause of Death; Cessation of life; Child; Childhood; Complex; Development; Disease; Dysautonomias; Dystonia; Electrocardiogram; Electrophysiology (science); Epilepsy; Etiology; Exhibits; Experimental Models; Foundations; Generations; Goals; Health; Heart; Heart Abnormalities; Heart Rate; Homeostasis; Human; Ice; In Vitro; Knock-in Mouse; Lead; Measurement; Measures; Mediating; Modeling; Molecular Target; Monitor; Morbidity - disease rate; Mus; Mutation; Myocardium; Na(+)-K(+)-Exchanging ATPase; Neurologic; Optics; Ouabain; Outcome; Paralysed; Pathologic; Patients; Pharmacology; Pharmacotherapy; Predisposition; Prevalence; Prevention; Pump; Recording of previous events; Risk Factors; Role; Seizures; Site; Sudden Death; Telemetry; Testing; Time; Tissue Model; Tissues; Variant; Ventricular Arrhythmia; Ventricular Fibrillation; alternating hemiplegia; base; chronotropic; clinically translatable; extracellular; genetic variant; human model; in vitro Model; in vivo; induced pluripotent stem cell; inhibitor; innovation; insight; molecular drug target; mouse model; novel; patch clamp; prevent; uptake

PROJECT SUMMARY/ABSTRACT Sudden unexplained death in epilepsy (SUDEP) is the sudden and unexplained death of a patient with a history of seizures and epilepsy who is in a reasonable state of health. It is a major cause of death in patients with epilepsy and a common cause of neurologic death overall. Believed to be caused by a culmination of cardiac and neurologic factors, epilepsy induced bradycardia is a risk factor for SUDEP and may trigger lethal ventricular arrhythmias in susceptible myocardium. Development of a robust experimental model which recapitulates this would open the door for foundational studies to develop critical pharmacotherapies. SUDEP is a tragic outcome in patients with alternating hemiplegia of childhood (AHC) which is characterized by epilepsy, dystonia, paralysis, and, notably, sudden death in the setting of bradycardia. Among AHC patients, 90% harbor underlying pathologic genetic variants in the ATP1A3-encoded alpha-3 catalytic subunit of the Na/K ATPase pump (ATP1A3). We have identified a strong correlation between the most common AHC-associated ATP1A3 variant (D801N) and short QT on ECG and ventricular fibrillation during bradycardia. Human induced pluripotent stem cell-derived cardiac myocytes from an ATP1A3-D801N-positive child (hiPSC-CMD801N) demonstrate shortened repolarization time, disrupted calcium homeostasis, and delayed-after depolarizations, which are triggers for arrhythmias. Knock-in mice hosting the D801N variant (Atp1a3D801N) have seizures, bradycardia, and sudden death. Further, Atp1a3D801N mice have a predisposition to ventricular arrhythmias, particularly at lower heart rates, compared to controls. Collectively, these findings raise the possibility that disruption of ATP1A3 in the heart underlies SUDEP in AHC patients through bradycardia-triggered arrhythmias. We hypothesize that D801N reduces pump function leading to shortened repolarization time and predisposes to lethal ventricular arrhythmias. Our goal is to use AHC as a model to establish the role ATP1A3 in the heart, determine the mechanism of SUDEP, and explore the proarrhythmic effect of bradycardia. To approach this in an innovative and rigorous way, we will utilize patient-derived hiPSCD801N- and murine Atp1a3D801N-based models for in vitro, ex vivo, and in vivo studies to determine the mechanism of arrhythmia predisposition in the heart. Specifically, we propose to determine 1) the mechanism of action potential duration shortening induced by D801N in cardiac myocytes, 2) the mechanism of cardiac arrhythmogenesis induced by D801N in 3D tissue models and ex vivo analysis, and 3) whether bradycardia due to seizures is an arrhythmogenic trigger for a “vulnerable” myocardium in Atp1a3D801N mice. In accomplishing these aims and overall goal, we will determine the function of ATP1A3 in cardiovascular physiology and its role in cardiac repolarization, calcium signaling, and ventricular arrhythmias, thus identifying molecular targets for pharmacotherapy. Finally, this will develop robust and rigorous models to determine the mechanisms of sudden death in AHC and will provide insights into mechanisms of SUDEP more broadly.

项目摘要/摘要 癫痫（SUDEP）突然无法解释的死亡是癫痫病史的患者突然而无法解释的死亡 和处于健康状态的癫痫病。这是癫痫患者的主要死亡原因和常见 整体神经病死亡的原因。认为是由心脏和神经系统因素的高潮引起的癫痫 诱导的心动过缓是SUDEP的危险因素，可能会引发易感心肌的致命性心律不齐。 开发强大的实验模型，该模型概括这将为基础研究打开大门 开发关键的药物治疗。 SUDEP是替代儿童偏瘫（AHC）患者的悲惨结果 其特征是癫痫，肌张力障碍，瘫痪，尤其是在心动过缓的情况下突然死亡。之中 AHC患者，有90％的患者具有ATP1A3编码的Alpha-3催化亚基的基础病理遗传变异 Na/K ATPase Pump（ATP1A3）。我们已经确定了最常见的AHC相关之间的密切相关性 心动过缓期间，ATP1A3变体（D801N）和ECG和心室纤维化的短QT。人类诱导的多能 来自ATP1A3-D801N阳性儿童（HIPSC-CMD801N）的干细胞衍生的心肌细胞表现出缩短 复置时间，钙稳态破坏和去极化后的延迟，这是心律不齐的触发因素。 拥有D801N变体（ATP1A3D801N）的敲门型小鼠癫痫发作，心动过缓和猝死。此外，ATP1A3D801N 与对照组相比，小鼠对心室心律不齐有易感性，尤其是在心率较低的情况下。共同 这些发现提出了一种可能性，即通过 心动过缓触发的心律不齐。我们假设D801N降低了泵的功能，导致缩短了重度 时间和易于致命的心室心律不齐。我们的目标是使用AHC作为模型来确定在 心脏，确定SUDEP的机制，并探索心动过缓的心律失常。接近这一点 一种创新和严格的方式，我们将利用患者来源的HIPSCD801N-和Murine ATP1A3D801N的模型 体外，体内和体内研究，以确定心律不齐倾向的机理。具体来说，我们 确定1）D801N在心肌细胞中诱导的动作潜在持续时间缩短的机理，2） D801N在3D组织模型和离体分析中诱导的心律失常发生的机制，以及3）是否是否 癫痫发作引起的心动过缓是ATP1A3D801N小鼠中“脆弱”心肌的心律失常触发。在 完成这些目标和整体目标，我们将确定AT​​P1A3在心血管生理学及其ITS中的功能 在心脏复精，钙信号传导和心室心律不齐中的作用，从而鉴定出分子靶标的 药物治疗。最后，这将开发出强大而严格的模型，以确定 AHC并将更广泛地提供对SUDEP机制的见解。