Mechanisms of calcium-induced arrhythmias in arrhythmogenic right ventricular cardiomyopathy

致心律失常性右室心肌病钙诱导心律失常的机制

• 批准号: 10539305
• 负责人: Francisco J Alvarado
• 金额: $ 38.88万
• 依托单位: UNIVERSITY OF WISCONSIN-MADISON
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-01-01 至 2026-12-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10539305
• 关键词: Ablation; Affect; Animals; Arrhythmia; Arrhythmogenic Right Ventricular Dysplasia; Biochemical; Calcium; Cardiac Myocytes; Cardiomyopathies; Cells; Cessation of life; Complex; Crossbreeding; Cyclic AMP-Dependent Protein Kinases; Cytosol; Data; Desmosomes; Disease; Disease Progression; Dislocations; Drug Targeting; Electrophysiology (science); Event; Exhibits; Functional disorder; Genes; Genetic; Goals; Heart; Heart Diseases; Heart failure; Hereditary Disease; Homeostasis; Human; Hyperactivity; Image; Incidence; Infiltration; Intercalated disc; Intercellular Junctions; Life Expectancy; Modeling; Molecular; Monitor; Mus; Mutation; Myocardial dysfunction; Patients; Pharmaceutical Preparations; Phase; Phenotype; Phosphorylation; Phosphorylation Site; Physiological; Post-Translational Protein Processing; Predisposition; Prevention; Protein Kinase C; Proteins; Public Health; Regulation; Reporting; Research; Right ventricular structure; Risk Reduction; Role; Ryanodine Receptor Calcium Release Channel; Sarcoplasmic Reticulum; Site; Sudden Death; Tamoxifen; Testing; Threonine; Ventricular; Ventricular Arrhythmia; defined contribution; disease phenotype; efficacy testing; human disease; imaging study; innovation; insight; novel; pharmacologic; plakophilin 2; prevent; receptor function; sudden cardiac death; therapeutic target

PROJECT SUMMARY / ABSTRACT Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a complex inherited disorder of the heart produced by mutation in proteins of the desmosome, such as plakophilin-2 (PKP2). Cardiac arrhythmias, and potentially sudden death, often occur in ARVC patients during the early stages of the disease, a “concealed phase” that presents before the onset of structural cardiomyopathy. The molecular and cellular mechanisms of these arrhythmic events remain unclear, hindering the search for effective strategies to treat patients. My long-term goal is to delineate the mechanisms of arrhythmia in ARVC and to identify potential drug targets to prevent sudden cardiac death. Mice with tamoxifen (TAM)-induced ablation of PKP2 (PKP2cKO) develop a phenotype evocative of human ARVC: a concealed stage with high incidence of arrhythmia but without structural remodeling at 14 days, cardiomyopathy of right ventricle dominance at 21 days, and biventricular cardiomyopathy, heart failure and death at ~42 days post-TAM. We reported that PKP2cKO hearts show significant dysregulation of Ca2+ handling at different stages of disease progression but, most remarkably, during the concealed stage of the disease. This proposal aims to elucidate the mechanisms underlying cardiac arrhythmia in PKP2-deficient hearts focusing on the microdomain where Ca2+ regulation takes place. I hypothesize that dysfunction of the cardiac ryanodine receptor (RyR2), a major intracellular Ca2+ release channel, and the ensuing Ca2+ mishandling are critical triggers of cardiac arrhythmia in the PKP2cKO mouse and, hence, in ARVC. These aims will test my hypothesis: 1) Determine the role of protein kinase C (PKC) phosphorylation in the regulation of RyR2 channel function and calcium homeostasis. Preliminary data suggest that RyR2 is undergoing phosphorylation in PKP2cKO hearts at Thr2810. This previously uncharacterized site is a predicted PKC substrate. I hypothesize that PKC phosphorylation of RyR2 at Thr2810 regulates channel function and contributes to arrhythmogenic Ca2+ release in the diseased heart. 2) Define the contribution of RyR2 dysfunction in the onset and progression of heart disease in PKP2cKO mice. Preliminary data suggest that RyR2 phosphorylation at Thr2810 and Ser2030 is increased in ARVC. I hypothesize that inhibition of RyR2 phosphorylation at these sites prevents arrhythmia and sudden death in PKP2cKO mice. 3) Test the efficacy of RyR2 modulators for the prevention of arrhythmia in PKP2-deficient hearts. I hypothesize that pharmacological modulation of RyR2 is beneficial to prevent arrhythmia in PKP2cKO mice and hearts. The completion of these aims will provide significant insight into the regulation of RyR2 function in a model of PKP2cKO deficiency and hence shed light on the mechanisms underlying ARVC. I anticipate these results will advance the status of RyR2 as a potential therapeutic target to reduce the risk of arrhythmias and increase life-expectancy of patients with ARVC.

项目摘要 /摘要 心律失常右心肌病（ARVC）是一种复杂的心脏遗传疾病 通过突变脱粒体的蛋白质，例如plakophilin-2（PKP2）。心律不齐，可能 突然死亡通常发生在疾病早期的ARVC患者中，这是一个“隐藏阶段” 在结构心肌病发作之前的礼物。这些的分子和细胞机制 心律不齐的事件尚不清楚，阻碍了寻找有效治疗患者的策略。我的长期 目标是描述ARVC中心律不齐的机制，并确定潜在的药物靶标以防止 突然心脏死亡。他莫昔芬（TAM）诱导的PKP2（PKP2CKO）的小鼠发展了表型 人类ARVC的回忆：一个隐藏的阶段，具有高度的心律失常，但没有结构重塑 在14天，右心室占优势的心肌病在21天，双脑膜炎心肌病，心脏 tam后约42天的失败和死亡。我们报道PKP2CKO心脏显示出明显的失调 Ca2+在疾病进展的不同阶段进行处理，但最引人注目的是，在隐藏阶段 疾病。该建议旨在阐明PKP2缺陷心脏心律不齐的基础机制 专注于发生Ca2+调节的微区域。我假设心脏功能障碍 Ryanodine受体（RYR2），主要的细胞内Ca2+释放通道，随后的Ca2+不当是 PKP2CKO小鼠中心律失常的关键触发因素，因此在ARVC中。这些目标将测试我 假设：1）确定蛋白激酶C（PKC）磷酸化在RYR2通道调节中的作用 功能和钙稳态。初步数据表明RYR2正在经历磷酸化 pkp2cko Hearts在Thr2810。以前未表征的位点是预测的PKC底物。我假设 RYR2在THR2810处的PKC磷酸化调节通道功能，并有助于心律不齐 Ca2+在解散的心脏中释放。 2）定义RYR2功能障碍在发作和进展中的贡献 PKP2CKO小鼠的心脏病。初步数据表明THR2810和SER2030的RYR2磷酸化 在ARVC中增加。我假设在这些位点抑制RyR2磷酸化可以防止心律不齐 PKP2CKO小鼠的猝死。 3）测试RYR2调节剂预防心律不齐的效率 在PKP2缺陷心中。我假设RYR2的药物调制有益于防止 PKP2CKO小鼠和心脏中的心律失常。这些目标的完成将为您提供重大见解 PKP2CKO缺乏症模型中RYR2功能的调节，因此阐明了机制 基础ARVC。我预计这些结果将把RYR2作为潜在的治疗靶点的状态提高到 降低心律不齐的风险并增加ARVC患者的寿命。