Elucidating the Origin of Sudden Cardiac Death in Dilated Cardiomyopathy: from Phenotype Predictors to Therapeutic Targets

项目摘要 扩张型心绞痛患者发生危及生命的心律失常的分子机制及临床预测因素 非缺血性心肌病(DCM)仍然难以捉摸，阻碍了适当的预防和治疗突发性 该人群中的心脏性死亡(SCD)和恶性室性心律失常(VA)。我们的应用程序将解决 这种未得到满足的需求。我们来自科罗拉多大学和斯坦福大学的成熟的调查团队 已经收集了初步数据和概念验证实验，以解决三个互补的目标，即 将全面填补DCM中危及生命的VA和SCD风险方面的关键知识空白。我们假设 扩张型心肌病的VA/SCD有两种主要机制：遗传因素(“致心律失常”基因)和 心脏纤维化。我们将用三个独立但互补的具体目标来解决这些假设 (临床的、翻译的和机械学的)旨在翻译机制的发现和描述 将预后转化为精准医学的方法。具体目标1将定义基因型和表型 扩张型心肌病恶性VA和SCD的预测因素我们的初步研究表明，表型，如 心肌纤维化和基因突变显著增加VA/SCD的风险。因此，我们假设一个 包括基因分型和先进成像在内的临床多学科方法可以准确地识别扩张型心肌病患者 有患SCD的风险。在家族性疾病中使用深层表型、结果测量和NextGen测序 心肌病登记(1,316名DCM受试者)，我们将生成SCD风险预测分数供临床使用。 特定目标2将识别VA的转录组签名。我们发现患者移植的心脏 致心律失常的扩张型心肌病有明显的转录特征。因此，我们假设，在高级阶段- 在DCM阶段，致命性心律失常是由基因决定的转录信号驱动的。我们将利用 NIH/NHLBI TOPMed项目的全基因组和转录组测序数据(X01 HL139403：1078 移植心脏，504个DCM，140个对照)以确定预测高危的基因特异性失调途径 弗吉尼亚州特异靶3将阐明致心律失常基因的分子机制。我们的预赛 突变的人类诱导多能干细胞来源的心肌细胞(HiPSC-CM)的数据表明 固有的电气不稳定性。然而，心脏成纤维细胞和CM/CF串扰在心律失常发生中的作用 仍然不为人知。我们假设致心律失常的DCM基因激活成纤维细胞并诱导心律失常， 直接或间接地通过它们与心肌细胞的相互作用。HiPSC-CM与心脏成纤维细胞 (HiPSC-CF)将从我们的注册中心(AIM 1)的60名患者中产生，并使用 致心律失常基因突变(LMNA、FLNC、DSP)和20名年龄/性别/种族匹配的健康人 个人。利用工程化心脏组织支架(EHT)，我们将阐明CFs激活的机制 和心律失常，比较IPSC衍生模型和移植心脏中改变的信号通路 队列(目标2)，并从药物上挽救表型。

Project Abstract The molecular mechanisms and the clinical predictors of life-threatening arrhythmias in patients with dilated, nonischemic cardiomyopathy (DCM) remain elusive, hampering adequate prevention and treatment of sudden cardiac death (SCD) and malignant ventricular arrhythmias (VA) in this population. Our application will address this unmet need. Our established team of investigators from the University of Colorado and Stanford University has assembled preliminary data and proof-of-concept experiments to tackle three complementary aims, which will comprehensively fill critical knowledge gaps in life-threatening VA and SCD risk in DCM. We hypothesize that two main mechanisms are involved in VA/SCD in DCM: genetic factors (“arrhythmogenic” genes) and cardiac fibrosis. We will address these hypotheses with three independent but complementary Specific Aims (clinical, translational and mechanistic) designed to translate the discovery of mechanisms and delineation of prognosis into a precision medicine approach. Specific Aim 1 will define genotype and phenotype predictors of malignant VA and SCD in DCM. Our preliminary studies show that phenotype, such as myocardial fibrosis, and gene mutations significantly increase the risk of VA/SCD. Thus, we hypothesize that a clinical multidisciplinary approach including genotype and advanced imaging can precisely identify DCM patients at risk of SCD. Using deep phenotyping, outcome measures, and NextGen sequencing in the Familial Cardiomyopathy Registry (1,316 DCM subjects), we will generate a SCD risk prediction score for clinical use. Specific Aim 2 will identify the transcriptome signature of VA. We found that explanted hearts of patients with arrhythmogenic DCM have a distinct transcriptional signature. Thus, we hypothesize that, in advanced- stage DCM, lethal arrhythmias are driven by genetically determined transcriptional signatures. We will leverage whole genome and transcriptome sequencing data from our NIH/NHLBI TOPMed project (X01 HL139403: 1078 explanted hearts, 504 DCM, 140 controls) to identify gene-specific dysregulated pathways predicting high-risk VA. Specific Aim 3 will elucidate the molecular mechanisms of arrhythmogenic genes. Our preliminary data in mutant human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CM) show evidence of intrinsic electrical instability. However, the role of cardiac fibroblasts and CM/CF cross-talk in arrhythmogenesis remains unknown. We hypothesize that arrhythmogenic DCM genes activate fibroblasts and induce arrhythmia, either directly or indirectly through their interaction with cardiomyocytes. hiPSC-CM and cardiac fibroblasts (hiPSC-CF) will be generated from 60 patients from our Registry (Aim 1) and genome edited models with mutations in arrhythmogenic genes (LMNA, FLNC, DSP), and 20 age/gender/ethnicity-matched healthy individuals. Using engineered heart tissue scaffolds (EHT), we will elucidate the mechanisms of CFs activation and arrhythmia, compare altered signaling pathways in iPSC-derived models with those in the explanted hearts cohort (Aim 2), and pharmacologically rescue the phenotype.