Genetic Signals in Ventricular Hypertrophy

摘要 左心室肥大（LVH）是一种常见的疾病，它增加了心血管疾病的风险。 事件和全因死亡率。我们实验室的研究和其他人的研究都有孟德尔形式的遗传原因， 左心室肥厚肌节蛋白基因的致病性变异占家族性肥厚型心肌病的50% (HCM)和约30%的散发性HCM。LVH也发生于非肌节基因的致病性变异，包括 PRKAG 2、GLA和LAMP 2。尽管取得了这一进展，但对所有已知LVH基因的详细遗传分析未能 在>50%的不明原因的孤立性LVH患者中确定致病性或可能致病性变异 （表示为iLVH）。为了解决这一知识缺口，我们利用全基因组测序（WGS）， 全面探讨iLVH的遗传病因。在NIH TOPMed程序（X 01 HL 143310，PI， J.G. Seidman），我们将从650名iLVH受试者中获得WGS数据， 使用RNA测序技术（RNAseq）分析来自这些受试者的相关iLVH组织。从WGS数据中，我们将识别罕见和常见 编码和非编码序列中可能导致或促成iLVH的变异。我们亦会考虑 线粒体变异、体细胞嵌合和/或病原体参与iLVH。 我们将使用诱导的多能干细胞衍生物来表征iLVH变体的功能影响。 心肌细胞（iPSC-CM）和评估肌节性能和心肌细胞生物学的新策略。 根据我们对在已建立的LVH基因中具有致病性变体的同基因iPSC-CM的分析，我们定义了 肌节收缩和松弛以及细胞能量学的精确异常。我们将扩大这些 分析已建立的LVH基因中其他致病变异的研究，以开发参考数据集 我们将比较iLVH受试者中鉴定的新变体的功能研究。并行分析 在已建立的LVH基因中，未知意义的变异（VUS）旨在改善LVH的临床解释。 这些丰富而神秘的变体通过将功能数据与来自心脏的RNAseq分析相结合， 我们将开始辨别PSC-CM的组织（从LVH和iLVH受试者获得）和RNAseq 对LVH和iLVH变体的转录应答。 我们希望这些研究将扩大我们对iLVH遗传结构的理解， 从而促进LVH患者合理治疗方法的发展。 这些数据也将丰富我们对肌节生理学的认识，使心肌细胞能够终身发挥功能。 或者引发疾病。更广泛地说，这些研究将有助于提供有关调控因素的信息， 调节心脏基因表达。具体而言，我们将： 1.分析全基因组序列和RNAseq中与iLVH相关的变体 2.确定LVH组织和iPSC-CM中致病性变体诱导的机制。 3.定义LVH和iLVH基因中编码和非编码VUS的致病性。

ABSTRACT Left ventricular hypertrophy (LVH) is a prevalent condition that conveys increased risk for cardiovascular events and all-cause mortality. Studies from our lab and others have genetic causes for Mendelian forms of LVH. Pathogenic variants in sarcomere protein genes account for ~50% of familial hypertrophic cardiomyopathy (HCM) and ~30% sporadic HCM. LVH also occurs from pathogenic variants in non-sarcomere genes including PRKAG2, GLA and LAMP2. Despite this progress, detailed genetic analyses of all known LVH genes fail to identify a pathogenic or likely pathogenic variant in >50% of individuals with isolated LVH that is unexplained (denoted as iLVH). To address this gap in knowledge we have harnessed whole genome sequencing (WGS) to comprehensively explore genetic cause of iLVH. Under the aegis of NIH TOPMed program (X01HL143310, PI, J.G. Seidman) we will obtain WGS data from 650 iLVH subjects and comprehensive transcriptional profiling (RNAseq) of associated iLVH tissues from these subjects. From WGS data we will identify rare and common variants in coding and noncoding sequences that may cause or contribute to iLVH. We will also consider the involvement of mitochondrial variants, somatic mosaicism, and/or pathogens in iLVH. We will characterize the functional impact of iLVH variants using induced pluripotent stem cell derived cardiomyocytes (iPSC-CMs) and new strategies to assess sarcomere performance and cardiomyocyte biology. From our analyses of isogenic iPSC-CMs with pathogenic variants in established LVH genes we defined precise abnormalities in sarcomere contraction and relaxation and cellular energetics. We will expand these analyses to studies of other pathogenic variants in established LVH genes so as to develop a reference dataset to which we will compare functional studies of novel variants identified in iLVH subjects. Parallel analyses of variants of unknown significance (VUS) in established LVH genes aim to improve the clinical interpretation of these abundant and enigmatic variants. By combining functional data with RNAseq analyses from cardiac tissues (obtained from LVH and iLVH subjects) and RNAseq of PSC-CMs we will begin to discern transcriptional responses to LVH and iLVH variants. We expect these studies will expand our understanding of the genetic architecture of iLVH and hypertrophic mechanisms and thereby promote the development of rationale therapeutics for LVH patients. These data will also enrich our insights of sarcomere physiology that enables life-long cardiomyocyte function or that incites disease. More broadly these studies will contribute to information about regulatory elements that modulate cardiac gene expression. Specifically we will: 1. Analyze whole genome sequences and RNAseq for variants associated with iLVH 2. Identify mechanisms induced by pathogenic variants in LVH tissues and iPSC-CMs. 3. Define the pathogenicity of coding and non-coding VUS in LVH and iLVH genes.