MBNL1's function in myofibroblast transformation and fibrosis

MBNL1 在肌成纤维细胞转化和纤维化中的功能

基本信息

批准号：
8719166
负责人：
Jennifer Michelle Davis
金额：
$ 13.11万
依托单位：
CINCINNATI CHILDRENS HOSP MED CTR
依托单位国家：
美国
项目类别：
财政年份：
2013
资助国家：
美国
起止时间：
2013-08-09 至 2015-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8719166
关键词：
Accounting Address Adult Affect Alternative Splicing Automobile Driving Binding Cardiac Cardiomyopathies Cell physiology Cells Cessation of life Chronic Cicatrix Clinical Clinical Management Contracts Cytokine Signaling Data Development Disease Embryo Environment Event Extracellular Matrix Fibroblasts Fibrosis Gene Expression Profile Gene Targeting Genes Genetic Heart Heart Diseases Heart failure Hybrids Hypertrophic Cicatrix Immunoprecipitation In Vitro Injury Intervention Knock-in Mouse Knockout Mice Laboratories Link Mechanical Stress Mechanics Mediating Mediator of activation protein Messenger RNA Modeling Molecular Molecular Genetics Mus Muscle Cells Myocardial Myocardial Infarction Myocardium Myofibroblast Myotonic Dystrophy Nodal Pathway interactions Phenotype Positioning Attribute Process Protein Isoforms Proteins Proteome Proteomics RNA RNA Binding RNA Splicing RNA-Binding Proteins Regulation Role Secretory Cell Signal Pathway Signal Transduction Smooth Muscle Myocytes Subcellular Fractions Sudden Death Testing Tissues Transcript Transgenic Organisms Treatment Efficacy United States Variant Wound Healing base defined contribution design drug discovery genetic activator genome wide association study improved in vivo injured mouse model novel overexpression periostin prevent programs remediation repaired research study response response to injury tissue repair tool

项目摘要

DESCRIPTION (provided by applicant): Cardiac fibrosis has rapidly emerged as one of the biggest problems affecting the clinical management of heart disease to date because current treatments only delay rather than prevent fibrotic remodeling and heart failure. Fibrosis results from an unrestrained tissue repair response orchestrated predominantly by the myofibroblast. Myofibroblasts are highly specialized cells characterized by a hybrid fibroblast/smooth muscle cell phenotype, as they can contract, migrate, and secrete vast amounts of extracellular matrix. The healthy heart is normally devoid of myofibroblasts, but injury-induced alterations of the mechanical and neurohumoral environment induce fibroblasts to transform into myofibroblasts. Initially, myofibroblast function is critical to the repair process as its contractile function and matrix secretion provides structural support to the injured myocardium; however, chronic myofibroblast activity eventually causes hypertrophic scarring and cumulative fibrosis, which is not only deleterious to cardiac function but creates a highly arrhythmogenic substrate. Due to the lack of genetic tools for specifically manipulating the fibroblast in vivo, the contribution ofthe fibroblast and myofibroblast to tissue repair and fibrotic disease has not been clearly defined. This proposal features two newly developed fibroblast-specific Cre knockin mouse models for delineating the fibroblast's role in myocardial repair and fibrosis and to identify the molecular regulators of the fibroblast-dependent fibrotic response. Currently, most studies examining the regulatory networks in myofibroblast transformation have been solely focused on TGF? signaling due to its central role in initiating myofibroblast transformation and fibrosis, providin a very limited scope of the regulatory networks driving the fibrotic process. This prompted us to perform a genome-wide screen for new molecular regulators of fibroblast to myofibroblast conversion from which we identified the gene for the RNA-binding protein muscleblind-like splicing regulator 1 (MBNL1). To date MBNL1 function has never been linked to tissue repair or fibrosis, but our preliminary data in primary fibroblasts (cardiac and MEFs) demonstrates that MBNL1 is both necessary and sufficient for inducing fibroblast to myofibroblast transformation, suggesting that MBNL1 is a primary mediator of fibrotic disease. Thus, this proposal is designed (1) to directly examine the mechanism by which injury induced changes in MBNL1's regulation of transcript abundance and alternative splicing alters the fibroblast's proteome to functionally transform into a myofibroblast and (2) to directly examine the role programmed fibroblast transformation by MBNL1 has in tissue repair and fibrotic disease. By defining the regulatory networks directing fibroblast to myofibroblast transformation this proposal will further delineate the cellular and molecular underpinnings for fibrotic disease which in turn should yield new invention points for developing targeted interventions and drug discovery as many of these molecular regulators should be amenable to pharmacologic remediation.

描述（由申请人提供）：心脏纤维化已迅速成为影响心脏病临床管理的最大问题之一，因为当前的治疗仅延迟而不是防止纤维化重塑和心力衰竭。纤维化是由肌成纤维细胞主要由肌纤维细胞精心策划的不受限制的组织修复反应引起的。肌纤维细胞是高度专业的细胞，其特征是杂化成纤维细胞/平滑肌细胞表型，因为它们可以收缩，迁移并分泌大量细胞外基质。健康的心脏通常没有肌纤维细胞，但是损伤引起的机械和神经肿瘤环境的改变会诱导成纤维细胞转变为肌纤维细胞。最初，肌纤维细胞功能对于维修过程作为其收缩功能至关重要基质分泌为受伤的心肌提供结构支持；然而，慢性肌纤维细胞活性最终会引起肥厚性疤痕和累积纤维化，这不仅对心脏功能有害，而且会产生高度心律失常的底物。由于缺乏特异性操纵体内成纤维细胞的遗传工具，因此尚未明确定义成纤维细胞和肌纤维细胞对组织修复和纤维化疾病的贡献。该提案具有两个新开发的成纤维细胞特异性CRE敲击小鼠模型，用于描述成纤维细胞在心肌修复和纤维化中的作用，并确定成纤维细胞依赖性纤维化反应的分子调节剂。目前，大多数研究肌纤维细胞转化中的调节网络的研究仅集中在TGF上？信号由于其在启动肌纤维细胞转化和纤维化中的核心作用而引起的信号传递，providin的调节网络的范围非常有限，驱动纤维化过程。这促使我们对成纤维细胞的新分子调节剂进行肌纤维细胞转化率进行了全基因组筛选，从中我们从中确定了RNA结合蛋白肌肉斑点样剪接调节剂1（MBNL1）的基因。迄今为止，MBNL1功能从未与组织修复或纤维化相关，但是我们在原发性成纤维细胞（心脏和MEF）中的初步数据表明，MBNL1既需要诱导成纤维细胞对肌纤维细胞转化，这表明MBNL1是纤维化疾病的原发性培养基。因此，该提案的设计（1）直接检查了损伤诱导的MBNL1调节的变化的机制，而替代剪接的调节可以改变成纤维细胞的蛋白质组，以在功能上转化为肌纤维细胞和（2），以直接检查MBNL1在MBNL1中的作用在组织中具有组织疾病的作用。通过定义将成纤维细胞引导到肌纤维细胞转化的调节网络，该提案将进一步描述纤维化疾病的细胞和分子基础，这反过来又应为有针对性的干预措施和药物发现产生新的发明点，因为这些分子调节剂应适用于药理学再审核。