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.

项目总结/摘要 致心律失常性右心室心肌病（ARVC）是一种复杂的心脏遗传性疾病， 通过桥粒蛋白质的突变，如斑嗜蛋白-2（PKP 2）。心律不齐，还有可能 猝死，经常发生在ARVC患者的疾病早期阶段，这是一个“隐藏期”， 在结构性心肌病发作前出现这些的分子和细胞机制 药物事件仍不清楚，阻碍了对治疗患者的有效策略的研究。我的长期 目的是描述ARVC中心律失常的机制，并确定潜在的药物靶点，以防止 心源性猝死三苯氧胺（TAM）诱导的PKP 2消融（PKP 2cKO）小鼠出现表型 诱发人类ARVC：心律失常发生率高但无结构重构的隐匿期 第14天，右心室优势型心肌病，第21天，双心室心肌病，心脏 TAM后约42天失败和死亡。我们报道了PKP 2cKO心脏表现出显著的 Ca 2+处理在疾病进展的不同阶段，但最显着的是，在隐藏阶段， 疾病该提案旨在阐明PKP 2缺陷心脏心律失常的潜在机制 重点关注Ca 2+调节发生的微区。我假设心脏功能障碍 兰尼碱受体（RyR 2），一个主要的细胞内钙释放通道，和随后的钙处理不当， 在PKP 2cKO小鼠中，因此在ARVC中，心脏心律失常的关键触发因素。这些目标将考验我的 假设：1）确定蛋白激酶C（PKC）磷酸化在RyR 2通道调节中的作用 功能和钙稳态。初步数据表明，RyR 2正在经历磷酸化， Thr 2810时的PKP 2cKO心脏。这个先前未表征的位点是预测的PKC底物。我假设 在Thr 2810处RyR 2的PKC磷酸化调节通道功能，并有助于促凋亡， Ca 2+在病变心脏中的释放。2)确定RyR 2功能障碍在疾病发作和进展中的作用 PKP 2cKO小鼠的心脏病。初步数据表明，RyR 2在Thr 2810和Ser 2030的磷酸化 在ARVC中增加。我假设在这些位点抑制RyR 2磷酸化可以防止心律失常 以及PKP 2cKO小鼠的猝死。3)测试RyR 2调节剂预防心律失常的功效 PKP 2缺乏的心脏。我假设RyR 2的药理学调节有利于预防 PKP 2cKO小鼠和心脏的心律失常。这些目标的完成将为我们提供重要的见解， PKP 2cKO缺陷模型中RyR 2功能的调节，从而阐明了其机制 潜在的ARVC。我预计这些结果将促进RyR 2作为潜在治疗靶点的地位， 降低心律失常的风险，延长ARVC患者的预期寿命。