Deciphering the role of Lmod2 in cardiac muscle and in dilatedcardiomyopathy

解读 Lmod2 在心肌和扩张型心肌病中的作用

基本信息

批准号：
10917836
负责人：
Carol C Gregorio
金额：
$ 56.14万
依托单位：
ICAHN SCHOOL OF MEDICINE AT MOUNT SINAI
依托单位国家：
美国
项目类别：
财政年份：
2015
资助国家：
美国
起止时间：
2015-04-01 至 2025-01-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10917836
关键词：
Actin-Binding Protein Actins Actomyosin Affect Antisense Oligonucleotides Binding Biochemistry Cardiac Cardiac Myocytes Cardiomyopathies Cellular biology Clinical Complementary DNA Data Dilated Cardiomyopathy Disease Etiology Family Family member Frameshift Mutation Functional disorder Funding Future Gene Family Generations Genes Genetic Goals Hand Heart Heart failure Human Impairment Intestines Knock-out Knockout Mice Lead Length Link Maintenance Mechanics Mediating Messenger RNA Microfilaments Molecular Biology Mus Muscle Muscle Contraction Muscle Weakness Muscle function Mutation Myocardium Myopathy Nemaline Myopathies Neonatal Nonsense Mutation Patients Physiological Play Predisposition Process Protein Binding Domain Protein Family Protein Isoforms Protein Truncation Proteins RNA Splicing Regulation Role Skeletal Muscle Smooth Muscle Structure Syndrome Terminator Codon Therapeutic Intervention Thin Filament Transcript Tropomyosin Work clinically relevant design disease-causing mutation heart function human disease human model improved in vitro Assay in vivo induced pluripotent stem cell induced pluripotent stem cell derived cardiomyocytes insight interdisciplinary approach mRNA Decay mouse model mutant neonate novel overexpression premature prevent protein expression spatial relationship tool

项目摘要

PROJECT SUMMARY Effective contractile force in muscle requires the proper assembly, regulation, and activation of actin-containing thin filaments. Leiomodins (Lmods) are a family of actin-binding proteins that regulate assembly of actin filaments through a single tropomyosin-binding and multiple actin-binding domains. We previously discovered that both knockout and overexpression of the cardiac predominant isoform (Lmod2) alters the lengths of thin filaments in vivo and results in cardiomyopathy. Our extensive preliminary data suggest that Lmod2 impacts contractile function - independent of actin-thin filaments length regulation. With a plethora of unique experimental tools in hand, the goal of this proposal is to definitively determine the mechanisms of how mutations in LMOD2 lead to heart failure. It is becoming increasingly clear that the Lmod family of proteins play a critical role in muscle function; mutations in any of the three LMOD isoforms lead to debilitating human diseases. In this proposal, we describe the first known human mutation in LMOD2. This mutation leads to severe neonatal dilated cardiomyopathy. All LMOD-linked diseases have the common underlying pathophysiology of severe muscle weakness due to reduced contractility. Most of the disease-causing mutations in the LMOD gene family are nonsense or frameshift mutations predicted to result in expression of truncated proteins. However, in nearly all cases of disease little to no LMOD protein is expressed. Extensive preliminary data suggests that nonsense-mediated mRNA decay underlies the loss of mutant LMOD2 protein, which we can restore using LMOD2-specific antisense oligonucleotides. We hypothesize that Lmod2 is a multifunctional protein that influences cardiac contractility through maintaining proper thin filament lengths and positively effecting activation of the thin filament. We propose a multidisciplinary approach utilizing a unique combination of in vitro assays, patient-specific induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs), and novel models of human disease to accomplish two Specific Aims focused on determining: 1) the fundamental function(s) of Lmod2, particularly how Lmod2 regulates thin filament assembly and what role it has in cardiac contractility, and 2) why human mutations in LMOD2 lead to a lack of protein expression, how loss of protein leads to disease, and whether restoring full-length or truncated LMOD2 can prevent (rescue) the onset of cardiomyopathy. Elucidating the in vivo function(s) of Lmod2 will provide critical missing links in our understanding of muscle contraction. In addition, these studies will have a broad impact on understanding the etiology and potential treatments of a spectrum of diseases that result from mutations in the LMOD family of genes, as well as other diseases that involve nonsense-mediated mRNA decay of essential proteins.

项目摘要肌肉中有效的收缩力需要适当的含肌动蛋白的组装，调节和激活细丝。 Leiomodins（LMODS）是调节肌动蛋白组装的肌动蛋白结合蛋白家族通过单个肌球蛋白结合和多个肌动蛋白结合域的细丝。我们以前发现了心脏主要同工型（LMOD2）的基因敲除和过表达都改变了薄的长度体内细丝并导致心肌病。我们广泛的初步数据表明LMOD2会影响收缩功能 - 独立于肌动蛋白 - 丝状长度调节。有很多独特的手头的实验工具，该提案的目的是确定确定如何的机制 LMOD2中的突变导致心力衰竭。越来越清楚的是，LMOD的蛋白质家族在肌肉功能中起着至关重要的作用。三种LMOD同工型中的任何一个中的突变导致人类疾病使人衰弱。在此提案中，我们描述 LMOD2中的第一个已知人类突变。这种突变导致严重的新生儿扩张性心肌病。全部 LMOD连接疾病具有严重肌肉无力的常见的基础病理生理学降低收缩力。 LMOD基因家族中大多数引起疾病的突变是胡说八道或预测将导致截短的蛋白质表达的移码突变。但是，在几乎所有情况下疾病几乎没有表达LMOD蛋白。广泛的初步数据表明，废话介导 mRNA衰变是突变型LMOD2蛋白损失的基础，我们可以使用LMOD2特异反义寡核苷酸。我们假设LMOD2是一种多功能蛋白，可通过保持适当的细丝长度，并积极影响细丝的激活。我们提出了一个多学科方法利用体外测定的独特组合，特定于患者诱导的多能干细胞衍生的心肌细胞（IPSC-CM）和人类疾病的新型模型旨在确定的目的：1）LMOD2的基本功能，特别是LMOD2如何调节薄细丝组件及其在心脏收缩性中的作用以及2）为什么人类突变在LMOD2中导致A 缺乏蛋白质表达，蛋白质的丧失如何导致疾病以及恢复全长还是截断 LMOD2可以预防（救援）心肌病的发作。阐明LMOD2的体内函数将在我们对肌肉收缩的理解中提供关键的缺失联系。此外，这些研究将有一个对了解一系列疾病的病因和潜在治疗的广泛影响 LMOD基因家族中的突变以及其他涉及废话介导的mRNA的疾病必需蛋白质的衰减。