The Role of 3-Dimensional Genome Integrity In Cardiac Laminopathies

项目摘要 LMNA基因的突变，该基因编码构成核纤层网络的A型核纤层蛋白， 引起广泛的疾病统称为核纤层蛋白病。LMNA是最常见的基因之一， 扩张型心肌病（DCM）是一种以心律失常和突发性心脏病为特征的不治之症， 死亡LMNA突变如何导致DCM尚不清楚。在哺乳动物基因组中，核纤层蛋白A 以细胞特异性方式在核周边的核纤层相关结构域（LAD）上染色质， 提示核纤层蛋白A蛋白在整个基因组完整性和转录调控中的关键作用。 然而，核纤层蛋白A在哪里以及如何与基因组相互作用，以及是否导致DCM的核纤层蛋白A突变， 在DCM中重组基因组结构仍然是难以捉摸的。这一建议的核心假设是， LMNA突变的一个子集通过核纤层蛋白A的结构功能丧失引起DCM，导致空间 基因组结构重组和异常基因表达。这个假设是基于强 初步数据显示，DCM LMNA突变导致单倍不足，并引发全基因组 患者特异性人诱导多能干细胞中伴随异常基因表达的LAD变化 干细胞衍生的心肌细胞（iPSC-CM）。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 负责LMNA突变引起的心脏特异性表型的分子病因学， 证明受损的核纤层蛋白A染色质和蛋白质相互作用导致DCM。在目标1中，我们将验证 3D基因组重组的破坏是LMNA相关DCM的致病机制。在目标2中， 将破译LMNA DCM中钙失调和心律失常的分子基础，在目标3中，我们将 通过调节局部基因组组织来开发治疗策略。我们提供了引人注目的 初步数据，以支持我们的假设驱动的研究建议的合理性。我们组建了一个 我们拥有一支多学科的团队，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新的范例，并为靶向治疗铺平道路。 LMNA相关DCM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.