The Role of 3-Dimensional Genome Integrity In Cardiac Laminopathies

项目摘要 LMNA基因突变，该基因编码构成核层网络的A型层蛋白， 导致一系列统称为椎板病的疾病。LMNA是最常见的基因之一 与扩张型心肌病(DCM)有关，这是一种以心律失常和心脏骤停为特征的不治之症 死亡。LMNA突变是如何导致DCM的，目前还知之甚少。在哺乳动物基因组中，层蛋白A相互作用 在细胞核外围的板层相关区域(LAD)上以细胞特有的方式染色质， 这表明Lamin A蛋白在整个基因组完整性和转录调控中起着关键作用。 然而，层蛋白A在哪里以及如何与基因组相互作用，以及是否导致DCM导致层蛋白A突变 重新排列DCM的基因组结构仍然难以捉摸。这一提议的中心假设是 LMNA突变亚集通过层蛋白A结构功能丧失导致DCM，导致空间 基因组结构重组和基因表达异常。这一假设是建立在强大的 初步数据显示DCM LMNA突变导致单倍性不足并触发全基因组 患者特异性人类诱导多能性中LADS伴随基因表达异常的变化 干细胞来源的心肌细胞(IPSC-CMS)。总而言之，我们的数据表明， 基因组完整性和DCM表型的失调。这项研究的首要目标是了解 LMNA突变引起的心脏特异性表型的分子病因学 证明层蛋白A染色质和蛋白质相互作用受损导致扩张型心肌梗死。在目标1中，我们将验证 3D基因组重组的破坏是LMNA相关性DCM的致病机制。在《目标2》中，我们 将破译LMNA DCM中钙调节失调和心律失常的分子基础，在目标3中我们将 通过调整当地的基因组组织来制定治疗策略。我们提供了令人信服的 初步数据支持我们以假设为导向的研究建议的合理性。我们已经组建了一支 多学科团队，我们有能力在四年内实现项目目标。如果成功， 我们的研究将为理解发病机制提供一个新的范式，并为有针对性的 与LMNA相关的扩张性心肌病的治疗。

Project Summary Mutations in the LMNA gene, which encodes type-A lamin proteins that constitute the nuclear lamina network, cause a broad spectrum of diseases collectively called laminopathies. LMNA is one of the most frequent genes involved in dilated cardiomyopathy (DCM), an incurable disease characterized arrhythmias and sudden cardiac death. How mutations in LMNA cause DCM is poorly understood. In the mammalian genome, lamin A interacts with chromatin in a cell-specific manner at lamina-associated domains (LADs) at the nuclear periphery, suggesting a key role for lamin A proteins in the overall genome integrity and transcriptional regulation. However, where and how lamin A interacts with the genome and whether DCM-causing lamin A mutations rearrange the genome architecture in DCM remains elusive. The central hypothesis of this proposal is that a subset of LMNA mutations cause DCM through loss of structural function of lamin A, leading to spatial reorganization of the genome architecture and aberrant gene expression. This hypothesis is based on strong preliminary data showing that a DCM LMNA mutation causes haploinsufficiency and triggers genome-wide changes in LADs concomitantly with aberrant gene expression in patient-specific human induced pluripotent stem cells derived cardiomyocytes (iPSC-CMs). Together our data suggest a mechanistic link between the dysregulation of genome integrity and the DCM phenotype. The overarching goal of the study is to understand the molecular etiology responsible for the cardiac-specific phenotypes caused by LMNA mutations and to demonstrate that impaired lamin A chromatin- and protein-interactions cause DCM. In Aim 1 we will validate the disruption of the 3D genome reorganization as a causative mechanism of LMNA-related DCM. In Aim 2 we will decipher the molecular basis of calcium dysregulation and arrhythmia in LMNA DCM, and in Aim 3 we will develop a therapeutic strategy by modulating the local genome organization. We provided compelling preliminary data to support the soundness of our hypothesis-driven research proposal. We have assembled a multidisciplinary team and we are well positioned to achieve the project goals within four years. If successful, our studies will provide a new paradigm for understanding the pathogenesis and pave the way for targeted therapies for LMNA-related DCM.