Ryanodine Receptor Defects in Cardiomyopathy Caused by Lamin A/C Gene Mutations

Lamin A/C 基因突变引起的心肌病中的 Ryanodine 受体缺陷

基本信息

批准号：
10376824
负责人：
ANDREW Robert MARKS
金额：
$ 45.3万
依托单位：
COLUMBIA UNIVERSITY HEALTH SCIENCES
依托单位国家：
美国
项目类别：
财政年份：
2019
资助国家：
美国
起止时间：
2019-04-04 至 2024-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10376824
关键词：
3-Dimensional Affect Amino Acids Apoptosis Arrhythmia Caliber Cardiac Cardiac Myocytes Cardiomyopathies Cell Differentiation process Cell Nucleus Cells Clinical Trials Cultured Cells DNA Damage Data Defect Dilated Cardiomyopathy Disease Disease model Filament Gene Mutation Genes Goals Heart Heart Diseases Heart failure Hereditary Disease Human Incidence Inherited Intermediate Filament Proteins Joints Knockout Mice Laboratories Lamin Type A Lamins Lead Life MAP2K1 gene MAPK3 gene Maps Membrane Mitochondria Mitogen-Activated Protein Kinase Kinases Modification Molecular Mus Muscular Dystrophies Mutant Strains Mice Mutation Myocardial dysfunction Myocardium Nuclear Envelope Nuclear Lamin Nuclear Lamina Oxidative Stress Oxides Pathogenesis Pathogenicity Pathologic Pathology Patients Peptide Hydrolases Pharmaceutical Preparations Pharmacotherapy Phenotype Physiological Process Production Proteins Proteomics Rare Diseases Reactive Oxygen Species Research RyR2 Ryanodine Receptor Calcium Release Channel Ryanodine Receptors Sarcoplasmic Reticulum Savings Signal Transduction Skeletal Muscle Striated Muscles Structure Sudden Death Testing Tissue Model Tissues Translating Translations Variant Work clinical development experimental study heart function human disease human model human subject human tissue improved inhibitor mitochondrial dysfunction mouse model novel novel therapeutics pre-clinical prevent protein structure small molecule three dimensional structure virtual

项目摘要

Project Summary Dilated cardiomyopathy caused by mutations in the lamin A/C gene (LMNA) encoding A-type nuclear lamins is a life-threatening disease with no definitive cure. The pathogenic mechanisms responsible for cardiomyopathy in this inherited disease are poorly understood. In particular, it is not known how alterations in proteins expressed in nuclei of virtually all terminally differentiated cells selectively cause heart disease. Our hypothesis is that alterations in A-type lamins predispose cells to oxidative stress-induced remodeling of ryanodine receptors (RyRs), creating a sarcoplasmic reticulum (SR) Ca2+ “leak.” Oxidative stress and increased cytosolic Ca2+ also contribute to hyper-activation of extracellular signal-regulated kinases 1 and 2 (ERK1/2), which occurs in cardiomyopathy caused by LMNA mutations. The increased cytosolic Ca2+ and ERK1/2 activity generates various defects, including mitochondrial dysfunction, that cause cardiomyopathy. A corollary of our hypothesis is that blocking the SR Ca2+ “leak” will have beneficial effects in cardiomyopathy caused by LMNA mutations. Using mouse models of the disease and human tissue, we will test our hypothesis and its corollary. In Aim 1, we will determine if alterations in A-type lamins that cause cardiomyopathy lead to enhanced cardiac muscle oxidative stress, resultant RyR2 remodeling and a SR Ca2+ “leak.” We will also determine if the SR Ca2+ “leak” stimulates ERK1/2 activity, causes mitochondrial dysfunction and damages DNA. In addition to heart, we will similarly examine skeletal muscle, which is often simultaneously affected in human patients with cardiomyopathy caused by LMNA mutations as well as in model mice. We will further assess these processes in cultured cells that stably express a cardiomyopathy-causing lamin A variant or lack A-type lamins. In Aim 2, we will utilize the three-dimensional structure of RyR to determine how specific oxidative modifications that occur in striated muscle of Lmna mutant mice affect its structure and make it “leaky” to Ca2+. In Aim 3, we will perform experiments to determine if a Rycal, drugs that stabilize remodeled RyRs and block the SR Ca2+ “leak,” improves heart function and prolongs survival in Lmna mutant mice and if it blocks the “leak” in hearts from human subjects with cardiomyopathy caused by LMNA mutations. We will further determine if a Rycal has synergistically beneficial effects when combined with an inhibitor of ERK1/2 activity, which has previously been shown to partially improve heart function in Lmna mutant mice with cardiomyopathy. These studies will reveal basic information about the pathogenesis of cardiomyopathy caused by LMNA mutations and connect an intranuclear protein defect with a tangible mechanism of cardiac dysfunction. They will also determine if drugs already in clinical development can be translated to trials in patients with this lethal heart disease.

项目概要由编码 A 型核纤层蛋白的核纤层蛋白 A/C 基因 (LMNA) 突变引起的扩张型心肌病是一种危及生命的疾病，无法根治心肌病的致病机制。人们对这种遗传性疾病知之甚少，尤其是蛋白质的改变是如何发生的尚不清楚。在几乎所有终末分化细胞的细胞核中表达的基因选择性地导致心脏病。 A 型核纤层蛋白的改变使细胞易于发生氧化应激诱导的兰尼定重塑受体 (RyRs)，产生肌浆网 (SR) Ca2+“氧化应激”和胞质增加。 Ca2+ 还有助于细胞外信号调节激酶 1 和 2 (ERK1/2) 的过度激活，发生在 LMNA 突变引起的心肌病中，胞浆 Ca2+ 和 ERK1/2 活性增加。产生各种缺陷，包括线粒体功能障碍，从而导致心肌病。假设阻断 SR Ca2+“泄漏”将对 LMNA 引起的心肌病产生有益作用我们将使用疾病和人体组织的小鼠模型来检验我们的假设及其推论。在目标 1 中，我们将确定导致心肌病的 A 型核纤层蛋白的改变是否会导致心脏功能增强。肌肉氧化应激、由此产生的 RyR2 重塑和 SR Ca2+“泄漏”。 Ca2+“泄漏”会刺激 ERK1/2 活性，导致线粒体功能障碍并损害 DNA。心脏，我们将类似地检查骨骼肌，骨骼肌通常同时受到患有心脏病的人类患者的影响我们将进一步评估 LMNA 突变引起的心肌病以及模型小鼠的这些过程。在稳定表达引起心肌病的核纤层蛋白 A 变体或缺乏 A 型核纤层蛋白的培养细胞中。我们将利用 RyR 的三维结构来确定特定的氧化修饰如何 Lmna 突变小鼠的横纹肌中发生的这种情况会影响其结构并使其“泄漏”Ca2+ 在目标 3 中，我们将进行实验以确定 Rycal 药物是否能稳定重塑 RyRs 并阻断 SR Ca2+ “泄漏”可以改善 Lmna 突变小鼠的心脏功能并延长其生存期，如果它能阻止心脏的“泄漏” 我们将进一步确定 Rycal 是否患有由 LMNA 突变引起的心肌病。与 ERK1/2 活性抑制剂联合使用时可产生协同有益效果，该抑制剂此前已被证实研究表明，该药物可部分改善患有心肌病的 Lmna 突变小鼠的心脏功能。有关 LMNA 突变引起的心肌病发病机制的基本信息并连接核内蛋白缺陷与心脏功能障碍的具体机制也将决定药物是否有效。已经进入临床开发阶段，可以转化为针对这种致命心脏病患者的试验。