Regulation of epicardial cell differentiation during development and disease

发育和疾病过程中心外膜细胞分化的调节

• 批准号: 8975800
• 负责人: Eric M Small
• 金额: $ 38.38万
• 依托单位: UNIVERSITY OF ROCHESTER
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-12-15 至 2018-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8975800
• 关键词: Address; Adult; Affect; Agonist; Apoptosis; Cardiac; Cardiac Myocytes; Cardiovascular Physiology; Cell Differentiation process; Cell Line; Cell physiology; Cells; Cicatrix; Complement Factor B; Complex; Contractile Proteins; Coronary; Coronary Vessels; Cues; Cytoplasm; Data; Development; Diffusion; Disease; Embryo; Embryonic Development; Epicardium; Fetal Heart; Fibroblasts; Fibrosis; Gene Activation; Gene Expression; Gene Expression Profile; Gene Targeting; Genes; Grant; Healed; Health; Heart; Histocompatibility Testing; Hypoxia; Injury; Invaded; Ischemia; Lead; Light; Mechanics; Mediating; Mesenchymal; Molecular; Mus; Myocardial Infarction; Myocardial Ischemia; Myocardium; Myofibroblast; Natural regeneration; Nuclear; Oxygen; Phenotype; Physiological; Population; Process; Production; Publishing; Regulation; Regulator Genes; Rho-associated kinase; Role; Serum Response Factor; Signal Transduction; Smooth Muscle Myocytes; Stem cells; Testing; Tissues; Transcriptional Regulation; WT1 gene; Work; angiogenesis; base; cardiac repair; cardiogenesis; cell motility; cell type; design; factor A; fetal; healing; heart cell; heart metabolism; myocardin; new therapeutic target; novel therapeutic intervention; precursor cell; programs; research study; response; rho; transcription factor

DESCRIPTION (provided by applicant): The epicardium is a single cell-layer mesothelial sheet that surrounds the heart and harbors a multi-potent progenitor cell population. Amazingly, epicardial-to-mesenchymal transition (EMT) leads to cardiac fibroblast and coronary vessel formation at the precise moment that diffusion fails to fuel the heart. The epicardial fetal gene program is re-awakened in ischemic heart disease and contributes to coronary neoangiogenesis and fibrosis. Surprisingly, none of the currently known regulatory mechanisms explain how EMT occurs in perfect synchrony with physiological demand. Serum response factor (SRF) is a widely expressed transcription factor that controls gene expression programs through interactions with tissue specific or signal responsive co- factors. Embryonic and adult cardiovascular function depends upon interactions between SRF and myocardin, which is specifically expressed in cardiomyocytes and smooth muscle cells, constitutively nuclear, and required for activation of genes encoding contractile proteins. Conversely, myocardin-related transcription factor (MRTF)-A and MRTF-B are broadly expressed, but held dormant in the cytoplasm until physiological signals lead to their nuclear accumulation. MRTF-A and -B promote differentiation of a mesenchymal / myofibroblast cell type in response to a growing list of agonists, including Rho-Rho kinase, TGF-¿1, and mechanical tension. Our recently published data reveal a critical role for MRTF-A in myofibroblast differentiation and scar formation following myocardial infarction. Our preliminary studies reveal SRF, MRTF-A and MRTF-B are enriched in the embryonic and adult epicardium and are required for EMT. Further, MRTF/SRF activity is induced by hypoxia and promotes a mesenchymal phenotype in cooperation with Wilms tumor 1 (WT1), including the coordinated regulation of guidance cues (Wnt signaling) and cytoskeletal components. Based on our preliminary data and the work of others, we hypothesize that physiological hypoxia in the epicardium promotes the synergistic interaction between MRTFs, SRF, and WT1 that drives EMT, coronary vessel formation and cardiac fibroblast production during development and disease. We will test this hypothesis with three Specific Aims that will define the molecular mechanisms underlying transcriptional regulation in the epicardium. Aim 1 will determine how MRTFs and SRF control epicardial cell function during development using conditional deletion of these factors and lineage tracing experiments in mice. Aim 2 will determine the transcriptional mechanism governing epicardial cell fate and function by defining the expression signature cooperatively regulated by SRF, MRTFs, and WT1 in the epicardium, and identify the physiological cues that modulate this gene regulatory axis. Aim 3 will define the role of MRTF-SRF in epicardial derived cell differentiation and cardiac function following myocardial infarction. These studies will test a paradigm-shifting hypothesis that explains the coordinated regulation of epicardial cell migration and differentiation by physiological cues and reveal novel therapeutic targets for the treatment of ischemic heart disease.

描述（由适用提供）：心外膜是一个单个细胞层间皮片，围绕着心脏，并拥有多功能的祖细胞群。令人惊讶的是，心外膜到 - 心质转变（EMT）会在扩散量无法助长心脏的精确时刻，导致心脏成纤维细胞和冠状动脉血管形成。心外膜胎儿基因程序在缺血性心脏病中重新唤醒，并有助于冠状动脉新血管结肠和纤维化。令人惊讶的是，当前已知的监管机制均未解释如何与身体需求完美同步。血清反应因子（SRF）是一种广泛表达的转录因子，它通过与组织特异性或信号响应式辅助因子相互作用来控制基因表达程序。胚胎和成人心血管功能取决于SRF和心肌蛋白之间的相互作用，SRF和心肌蛋白在心肌细胞和平滑肌细胞中特异性表达，是组成性核的，并且是激活编码收缩蛋白的基因所必需的。相反，与心肌相关的转录因子（MRTF）-A和MRTF-B广泛表达，但在细胞质中处于休眠状态，直到物理信号导致其核积累。 MRTF-A和-B促进了越来越多的激动剂列表，包括Rho-Rho激酶，TGF- - 1和机械张力，促进了间充质 /成肌纤维细胞类型的分化。我们最近发表的数据揭示了MRTF-A在心肌梗塞后的肌纤维细胞分化和疤痕形成中的关键作用。我们的初步研究表明，SRF，MRTF-A和MRTF-B富集在胚胎和成人心外膜中，并且需要EMT。此外，MRTF/SRF活性是由缺氧诱导的，并与Wilms肿瘤1（WT1）合作促进间充质表型，包括对指导线索的协调调节（WNT信号传导）和细胞骨架成分。基于我们的初步数据和其他人的工作，我们假设心外膜中的物理缺氧促进了MRTF，SRF和WT1之间的协同相互作用，从而驱动EMT，冠状动脉血管形成，心脏血管形成以及发育和疾病期间的心脏成纤维细胞产生。我们将以三个特定的目的来检验这一假设，以定义心外膜转录调控的分子机制。 AIM 1将确定在发育过程中使用这些因素的条件缺失以及小鼠中的谱系追踪实验在发育过程中如何控制心外膜细胞功能。 AIM 2将通过定义表达中由SRF，MRTFS和WT1协调调节的表达签名来确定控制心外膜细胞命运和功能的转录机制，并确定调节该基因调节轴的物理线索。 AIM 3将定义MRTF-SRF在心膜衍生的细胞分化和心肌梗塞后的心脏功能中的作用。这些研究将检验一个范式转移假说，该假设解释了通过物理线索对心外膜细胞迁移和分化的协调调节，并揭示了治疗缺血性心脏病的新型治疗靶标。