Unraveling the pathogenesis of familial dilated cardiomyopathy towards precision medicine

项目概要 扩张型心肌病（DCM）是心力衰竭的主要原因。遗传性 DCM 具有家族遗传性，现已成为 诊断更为常见，占报告病例的一半。尽管解谜工作取得进展 DCM的遗传基础，我们对分子事件和信号传导的理解仍然存在很大差距 从突变导致多种疾病表型的途径。最近新技术的出现， 例如患者特异性诱导多能干细胞 (iPSC) 和基因组编辑 (CRISPR/Cas9)，提供 这是研究遗传变异与疾病易感性之间关系的前所未有的机会。由 结合这些突破性技术，我们现在准备解决最关键的问题之一 家族性 DCM，即不断增长的 DCM 相关基因型与表型关系 基因突变。我们提案的总体目标是利用多学科方法，将 患者特异性 iPSC、基因组编辑、基因筛选、下一代测序技术和 转基因动物模型以获得对基因型-表型关联的新见解，并剖析 遗传性 DCM 发病机制的分子机制。我们的初步研究表明， 模型中 DCM 发病机制中内质网 (ER) 中的未折叠蛋白反应 (UPR) 患者特异性 iPSC-CM。修订提案的中心假设是某些 DCM 突变 改变 Ca2 稳态并引起慢性 ER 应激，导致 UPR 信号传导延长激活。我们 将追求三个具体目标。目标1：我们将建立一个实验平台来研究基因型- 心肌肌钙蛋白 T (TNNT2) 和受磷蛋白 (PLN) 基因变异相关的表型关联 与 DCM；目标 2：我们将破译 ER 应激和 UPR 激活在遗传性 DCM 中的作用；在目标 3 中： 探究与体内 TNNT2 突变相关的 DCM 发病机制。我们有 组建了一支具有广泛互补和综合专业知识的多学科团队。我们有 提供了令人信服的初步数据来支持我们的假设驱动研究提案的合理性， 我们完全有能力在五年内实现项目目标。如果成功的话，我们的研究将提供 理解家族性 DCM 发病机制和治疗的新范例。

Project Summary Dilated cardiomyopathy (DCM) is a leading cause of heart failure. Genetic DCM, which runs in families, is now more commonly diagnosed, accounting for up to half of the reported cases. Despite the progress in unraveling the genetic basis of DCM, there is still a large gap in our understanding of the molecular events and signaling pathways that lead from a mutation to diverse disease phenotypes. The recent advent of new technologies, such as patient-specific induced pluripotent stem cells (iPSCs) and genome editing (CRISPR/Cas9), provide an unprecedented opportunity to study associations between genetic variability and disease susceptibility. By combining these breakthrough technologies, we are now poised to address one of the most critical issues in familial DCM, namely, the genotype-phenotype relationship from the ever-growing number of DCM-associated gene mutations. The overarching goal of our proposal is to utilize a multidisciplinary approach that integrates patient-specific iPSCs, genome editing, genetic screens, next generation sequencing technologies and transgenic animal models to gain novel insights into genotype-phenotype associations, and to dissect the molecular mechanism of genetic DCM pathogenesis. Our preliminary studies have implicated the activation of the unfolded protein response (UPR) in the endoplasmic reticulum (ER) in the pathogenesis of DCM in a model of patient-specific iPSC-CMs. The central hypothesis of the revised proposal is that certain DCM mutations alter Ca2+ homeostasis and cause chronic ER stress, leading to prolonged activation of the UPR signaling. We will pursue three specific aims. In aim 1: we will establish an experimental platform to study the genotype- phenotype association of cardiac troponin T (TNNT2) and phospholamban (PLN) gene variants associated with DCM; in aim 2: we will decipher the role of ER stress and UPR activation in genetic DCM; and in aim 3: interrogate the mechanisms of DCM pathogenesis associated with TNNT2 mutations in vivo. We have assembled a multi-disciplinary team with extensive complementary and integrated expertise. We have provided compelling preliminary data to support the soundness of our hypothesis-driven research proposal, and we are well positioned to achieve the project goals within five years. If successful, our studies will provide a new paradigm for understanding the pathogenesis and treatment of familial DCM.