Targeting the genotype to phenotype link in HCM as a therapeutic strategy

室性心律失常和心脏性猝死(SCD)是肥厚性心脏病的常见并发症。 心肌病(HCM)，尤其是年轻人。肉瘤蛋白基因的致病变异体 导致大约一半的遗传性肥厚性肥厚和大约三分之一的散发性肥厚性肥厚。然而，人们对此知之甚少。 肌节蛋白变异如何导致心律失常和心源性猝死。有一个重大的未满足的问题 需要更好地了解疾病机制，以便预测有SCD和 设计以机制为基础的疗法。 为了解决这一差距，我们将应用高通量功能基因组学来鉴定单个蛋白质 致心律失常信号的成分，并利用IPSC的体外研究建立它们的功能。 来源的心肌细胞(IPSC-CMS)和HCM突变小鼠的体内研究。我们将从 产生IPSC细胞内致心律失常信号的功能基因组探针 心肌细胞携带MYBPC3、MYH7和TNNT2的HCM致病变异体。探测器将是 基于筛选合成的miRNAs(syn-miRs)识别，这些miRNAs共同抑制几乎所有 细胞中的蛋白质，因此是复杂生物学的理想探针。探头选择性分析 因为基因变异将表明存在共同和/或不同的信号机制。同时， 我们将通过分析肌切样本来确定和表征候选通路 来自MYBPC3突变的HCM患者。一旦我们获得了路径信息和探测器 这两种方法，我们将通过高通量综合确定蛋白质介体 MYBPC3突变体IPSC-CMS的功能评价基于IPSC-CMS中的效果， MYBPC3的选择性和作为药物靶点的潜力，我们将优先考虑最有希望的候选者 携带MYBPC3突变的HCM转基因小鼠AAV9基因敲除的体内评价靶点 与IPSC-CMS中的同源基因。我们预计，调整候选人的功能 介体将抑制MYBPC3突变小鼠的心律失常和心动过速。 总而言之，这些研究将增加我们对致心律失常信号的理解。 HCM基因突变与促进预后改善及机制探讨 家族性肥厚型心肌炎患者的治疗。它还将增加我们对基本知识的理解 心肌细胞生物学可能是其他心脏疾病的基础。具体目标是：1)确定 如果离散的信号机制导致高倾向HCM基因的心律失常易感性 变异体，以及2)通过功能全面定义决定电重构的蛋白质 MYBPC3突变体IPSC-CMS的筛选及其作为MYBPC3治疗靶点的研究 人巨细胞瘤突变小鼠模型。

Ventricular arrhythmia and sudden cardiac death (SCD) is a prevalent complication of hypertrophic cardiomyopathy (HCM) especially in young adults. Pathogenic variants of sarcomeric protein genes cause about half of inherited HCM and about a third of sporadic HCM. Little is known, however, about how sarcomeric protein variants lead to arrhythmia and sudden cardiac death. There is a major unmet need for a better understanding of disease mechanisms in order to predict patients at risk for SCD and design mechanism-based therapeutics. To address this gap, we will apply high throughput functional genomics to identify individual protein components of arrhythmogenic signaling, and establish their function using in vitro studies in iPSC- derived cardiomyocytes (iPSC-CMs) and in vivo studies in HCM mutant mice. We will begin by generating functional genomics probes of the intracellular arrhythmogenic signaling in iPSC-derived cardiomyocytes carrying HCM causative variants in MYBPC3, MYH7 and TNNT2. The probes will be identified based on screening synthetic miRNAs (syn-miRs) which collectively suppress nearly all proteins in the cell and therefore make ideal probes of complex biology. Analysis of probe selectivity for gene variants will indicate the existence of common and/or distinct signaling mechanisms. In parallel, we will identify and characterize candidate pathways indicated from analysis of myectomy samples from MYBPC3 mutant HCM patients. Once we have obtained pathway information and probes from these two approaches, we will comprehensively determine the protein mediators by high throughput functional evaluation in the MYBPC3 mutant iPSC-CMs. Based on the effect in the iPSC-CMs, selectivity for MYBPC3 and potential as a drug target, we will prioritize the most promising candidate targets for in vivo evaluation by AAV9 knockdown in HCM transgenic mice carrying a Mybpc3 mutation homologous to that in the iPSC-CMs. We expect that modulating the function of the candidate mediators will suppress arrhythmia and tachycardia in the Mybpc3 mutant mice. In summary, these studies will increase our understanding of the arrhythmogenic signaling caused by HCM mutations and promote the development of improved prognostic and mechanism-based therapeutics for familial HCM patients. It will also increase our understanding of fundamental cardiomyocyte biology that might underlie other cardiac diseases. The Specific Aims are: 1) Determine if discrete signaling mechanisms cause arrhythmic susceptibility across “high” propensity HCM gene variants, and 2) Comprehensively define the proteins that dictate electrical remodeling by functional screening in MYBPC3 mutant iPSC-CMs and test their efficacy as therapeutic targets in an Mybpc3 mutant mouse model of HCM.