The Stress Response Kinase JNK and Alcohol Evoked Atrial Fibrillation

过量饮酒(在短时间内大量饮酒)已普遍存在 房颤是临床诊断中最常见的心律失常，被认为是房颤的高危因素。 练习一下。尽管到目前为止已经做出了重大努力来减少酗酒，但反复酗酒的情况仍然存在 在全国范围内流行，因此酒精相关房颤的患病率很高。这导致了一个巨大的 房颤消融手术费用昂贵，消融后房颤复发率高，给社会带来经济负担 如果患者同时患有心血管疾病。不幸的是，目前可用的药物治疗 由于缺乏对其潜在机制的了解，酒精性房颤的发生仍然无效。我们的 拟议的研究将通过识别应激反应c-jun氨基末端激酶来填补这一重要的知识空白 (JNK)在酒精性房颤的发生中起着重要的调节作用。众所周知，JNK与酒精有关 细胞死亡和组织损伤。我们最近首次报道了激活的JNK在房颤底物中起关键作用 房颤的形成和发展。这种JNK-AF关系提供了一条逻辑路径，酒精可以通过它 增加房颤的倾向。事实上，我们的初步人类和动物实验结果表明，过量饮酒 暴露极大地增加了JNK的激活，从而增强了钙调蛋白II型激酶(CaMKII，众所周知的 促心律失常分子)依赖的肌浆网(SR)钙泄漏和异常的舒张期钙火花/波， 因此增加了房性心律失常的倾向。显性负突变失活JNK转基因小鼠 减轻这些酒精引起的异常钙活动。在这份提案中，JNK在RyR频道上的贡献 功能障碍和异常的钙活动将使用独特的小鼠模型进行解剖，并通过基因操作 JNK或CaMKII活性或RyR2单通道功能。可能会将鼠标模型的结果转换为 人类，我们将在人类捐赠者的心脏上进行验证研究。我们将使用互补的电生理学 方法(电压/钙双通道光学标测和共聚焦钙成像)完整的心房/分离的心房肌细胞 以及体内房颤诱导)和生化技术，以获得关系的全面图景 酒精激活的JNK和钙通过增加RyR2介导的肌浆网钙泄漏(Aim1)触发的房颤之间的关系。这个 酒精诱导的JNK改变RyR2通道功能以增加SR泄漏和火花/波的机制基础 (目标2)将详细介绍临床上慢性阻塞性肺疾病小鼠心房肌细胞通透性和单个RyR2通道的水平。 使用人类供体心脏组织验证了其适用性。该提案整合了重要的功能度量 和基础机械论研究，以及适当的替代方法。药理干预 限制JNK活性和修饰RyR2通道功能将被测试为潜在的治疗方案，以防止 和/或治疗房颤。JNK的RyR2活动也可能增加与其他应激相关的心律失常风险(例如，衰老、肥胖、心脏 失败等)。因此，这里定义的潜在机制和测试的治疗干预可能会延长 酒精相关房颤之外的潜在意义。

Excessive binge alcohol intake (large amount of drinking within a short period of time) has been widely recognized as a high risk factor for atrial fibrillation (AF), which is the most common arrhythmia in diagnosed clinical practice. Although significant efforts have been made to date to reduce binge drinking, repeated binge remains prevalent nationwide and consequently the prevalence of alcohol associated AF is high. This causes a tremendous economic burden on our society due to expensive AF ablation procedures and high rate of recurrent AF after ablation if patients have coexisting cardiovascular diseases. Unfortunately, currently available pharmacological therapies for alcohol-provoked AF genesis remain ineffective due to a lack of understanding of its underlying mechanisms. Our proposed studies would fill this important knowledge gap by identifying stress-response c-Jun N-terminal kinase (JNK) as an important regulator in alcohol-provoked AF genesis. JNK is known to contribute to alcohol associated cell death and tissue injury. We have recently reported for the first time that activated JNK is critical in AF substrate formation and AF development. This JNK-AF relationship provides a logical pathway through which alcohol may increase propensity for AF. Indeed, our preliminary human and animal results indicate that excessive binge alcohol exposure dramatically increases JNK activation, which enhances calmodulin type II kinase (CaMKII, a well-known pro-arrhythmia molecule) dependent sarcoplasmic reticulum (SR) Ca leak and aberrant diastolic Ca sparks/waves, thus increasing propensity for atrial arrhythmias. Inactivated JNK transgenic mice with dominant negative mutations attenuated these alcohol-provoked abnormal Ca activities. In this proposal, the JNK contribution on RyR channel dysfunction and abnormal Ca activities will be dissected using unique mouse models with genetically manipulated JNK or CaMKII activities or RyR2 single channel function. To potentially translate results from mouse models to humans, we will perform validation studies in human donor hearts. We will use complementary electrophysiological approaches (voltage/Ca dual channel optical mapping and confocal Ca imaging in intact atria/isolated atrial myocytes as well as in vivo AF induction) and biochemical techniques to gain a comprehensive picture of the relationship between alcohol-activated JNK and Ca-triggered AF via increased RyR2-mediated SR Ca leak (Aim1). The mechanistic basis of how alcohol-evoked JNK alters RyR2 channel function to increase SR leak and sparks/waves (Aim 2) will be detailed at the levels of permeabilized atrial myocytes and single RyR2 channels in mice with clinical applicability verified using human donor heart tissue. This proposal integrates important functional measurements and fundamental mechanistic studies along with appropriate alternative approaches. Pharmacological interventions that limit JNK activity and modify RyR2 channel function will be tested as potential therapeutic options to prevent and/or treat AF. JNK’s RyR2 action may also add to arrhythmia risk tied to other stresses (e.g. aging, obesity, heart failure, etc.). Thus, the underlying mechanism defined and therapeutic interventions tested here may extend the potential significance beyond alcohol associated AF.