Mechanisms of calcium-induced arrhythmias in arrhythmogenic right ventricular cardiomyopathy

致心律失常性右心室心肌病钙诱导心律失常的机制

基本信息

批准号：
10346038
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
项目类别：
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/10346038
关键词：
Ablation Affect Animals Arrhythmia Arrhythmogenic Right Ventricular Dysplasia Biochemical Calcium Cardiac Myocytes Cardiomyopathies 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 Lead Life Expectancy Light Modeling Molecular Monitor Mus Mutation Myocardial dysfunction Patients Pharmaceutical Preparations Pharmacology 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 Role Ryanodine Receptor Calcium Release Channel Sarcoplasmic Reticulum Site Sudden Death Tamoxifen Testing Threonine Ventricular Ventricular Arrhythmia defined contribution disease phenotype efficacy testing heart cell human disease imaging study innovation insight novel plakophilin 2 prevent receptor function sudden cardiac death therapeutic target

项目摘要

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.

项目概要/摘要致心律失常性右室心肌病 (ARVC) 是一种复杂的遗传性心脏疾病桥粒蛋白突变，例如 plakophilin-2 (PKP2)，并可能导致心律失常。猝死通常发生在 ARVC 患者的疾病早期阶段，这是一个“隐蔽阶段”，出现在结构性心肌病发生之前的分子和细胞机制。心律失常事件仍不清楚，阻碍了寻找治疗患者的有效策略。目标是描述 ARVC 心律失常的机制并确定潜在的药物靶点来预防他莫昔芬 (TAM) 诱导的 PKP2 消融 (PKP2cKO) 小鼠出现心源性猝死。人类 ARVC 的唤起：心律失常发生率高但无结构重塑的隐蔽阶段第 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 天出现衰竭和死亡我们报道 PKP2cKO 心脏表现出明显的失调。 Ca2+ 在疾病进展的不同阶段进行处理，但最不寻常的是在疾病的隐蔽阶段该提案旨在阐明 PKP2 缺陷心脏中心律失常的机制。我关注了 Ca2+ 调节发生的微区，追踪了心脏功能障碍。兰尼碱受体 (RyR2)，一种主要的细胞内 Ca2+ 释放通道，以及随之而来的 Ca2+ 错误处理 PKP2cKO 小鼠心律失常的关键触发因素，因此，在 ARVC 中，这些目标将考验我。假设：1）确定蛋白激酶C（PKC）磷酸化在RyR2通道调节中的作用初步数据表明，RyR2 正在经历磷酸化。位于 Thr2810 的 PKP2cKO 心脏。这个先前未表征的位点是预测的 PKC 底物。 PKC 的 RyR2 Thr2810 磷酸化可调节通道功能并导致心律失常患病心脏中的 Ca2+ 释放 2) 定义 RyR2 功能障碍在发病和进展中的作用。初步数据表明，RyR2 在 Thr2810 和 Ser2030 处磷酸化。 ARVC 中的 RyR2 磷酸化增加，我认为抑制这些位点的 RyR2 磷酸化可以预防心律失常。和 PKP2cKO 小鼠猝死 3) 测试 RyR2 调节剂预防心律失常的功效。在 PKP2 缺陷的心脏中，我敢说 RyR2 的药物调节有利于预防。 PKP2cKO 小鼠和心脏的心律失常的完成这些目标将为我们提供重要的见解。在 PKP2cKO 缺陷模型中调节 RyR2 功能，从而揭示其机制我预计这些结果将提升 RyR2 作为潜在治疗靶点的地位。降低心律失常的风险并延长 ARVC 患者的预期寿命。