Molecular regulation of heart valve development and function.

心脏瓣膜发育和功能的分子调节。

• 批准号: 8271380
• 负责人: Joy Lincoln
• 金额: $ 36.2万
• 依托单位: RESEARCH INST NATIONWIDE CHILDREN'S HOSP
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-08-01 至 2014-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8271380
• 关键词: Address; Adenoviruses; Adult; Attenuated; Birds; Cartilage; Cell Differentiation process; Cell Lineage; Cells; Collagen; Connective Tissue; Data; Defect; Development; Disease; Drug or chemical Tissue Distribution; Echocardiography; Equilibrium; Extracellular Matrix; Genes; Goals; Heart Valve Diseases; Heart Valves; Immunohistochemistry; In Vitro; Incidence; Individual; Knockout Mice; Life; MAPK3 gene; Maintenance; Methods; Molecular; Mus; Nuclear; Operative Surgical Procedures; Population; Process; Regulation; Reporting; Reverse Transcriptase Polymerase Chain Reaction; Signal Pathway; Signal Transduction; Small Interfering RNA; Staging; Structural Genes; Structure; System; Tenascin; Tendon structure; Testing; Therapeutic; Tissues; Undifferentiated; United States; Work; abstracting; cartilage development; cell determination; cell type; clinically relevant; clinically significant; congenital heart disorder; gain of function; gene function; in vivo; malformation; molecular phenotype; mortality; overexpression; precursor cell; proto-oncogene protein kfgf; repaired; research study; scleraxis; transcription factor

Project Summary/Abstract Heart valve disease, including structural malformations, is the leading cause of mortality in adults. Despite the clinical relevance, the molecular mechanisms required for heart valve formation and function are not well defined. Normal mature heart valve leaflets and supporting structures are differentially composed of diversified extracellular matrix and cell lineages organized to facilitate normal valve function. In contrast, diseased or malfunctioning valves display drastic alterations in connective tissue distribution. We have shown that mature valve supporting structures express the bHLH transcription factor scleraxis and genes associated with tendon cell types. In contrast, valve leaflets express markers related to cartilaginous cell lineages. These specialized cell types are derived from a common population of undifferentiated precursor cells and we have reported that signaling pathways important for valve precursor cell differentiation in vitro are common with tendon and cartilage development. Using an avian in vitro system developed in our lab we have generated data to suggest that ERK1/2-Smad1/5/8 signaling, and activation of downstream scleraxis, are important for valve precursor cell determination and differentiation of a tendon-like lineage that forms valve supporting structures. However further work is required to define these regulatory hierarchies in the development and maintenance of diversified valve structures. Therefore, experiments in avian valve cells in vitro will be used to determine the consequences of altered ERK1/2 and scleraxis function on lineage differentiation in valve precursors and mature valve cells. In addition, generated mice with conditional loss of scleraxis function in vivo will determine the requirements of scleraxis for valve formation and function. The specific aims of the proposed project are to: 1. Determine if antagonistic ERK1/2 and Smad1/5/8 signaling regulates valve precursor cell fate to promote differentiation of tendon- or cartilage-like cell types. 2. Determine if scleraxis is necessary and sufficient to promote tendon-like cell differentiation in valve precursor cells and maintain extracellular matrix organization in mature valve structures. 3. Determine if scleraxis is required for tendon-like cell differentiation and formation of supporting valve structures in vivo. Testing this hypothesis will determine molecular mechanisms important for normal valve development and maintenance. In addition proposed studies will identify regulatory interactions that may underlie congenital valve disease and adult valve degeneration associated with alterations in connective tissue composition and distribution. Project Narrative Heart valve defects occur in at least 5 million individuals in the United States and the incidence of valve disease is increasing with over 95,0000 surgical procedures to repair or replace malformed valves performed in the US in 2003. However current valve alternatives are limited and often temporary due to inappropriate replacements that fail to grow, remodel, repair or withstand life-long demands. Increased understanding of the processes required for valve development and maintenance has potential clinical significance in identifying genes associated with congenital heart disease and adult valve degeneration, as well as advancing current therapeutic applications.

项目概要/摘要 心脏瓣膜疾病，包括结构畸形，是成人死亡的主要原因。 尽管具有临床相关性，但心脏瓣膜形成和形成所需的分子机制 功能没有明确定义。正常成熟的心脏瓣膜小叶和支撑结构是 由多样化的细胞外基质和细胞谱系组成，以促进正常 阀门功能。相反，患病或故障的瓣膜显示结缔组织的剧烈变化 组织分布。我们已经证明成熟的瓣膜支撑结构表达了 bHLH 转录因子硬化和与肌腱细胞类型相关的基因。相比之下，瓣叶 表达与软骨细胞谱系相关的标记。这些特殊的细胞类型源自 未分化前体细胞的常见群体，我们报道了信号通路 对体外瓣膜前体细胞分化很重要，常见于肌腱和软骨 发展。使用我们实验室开发的禽类体外系统，我们生成的数据表明 ERK1/2-Smad1/5/8 信号传导和下游巩膜轴的激活对于瓣膜很重要 形成瓣膜支撑的肌腱样谱系的前体细胞测定和分化 结构。然而，需要进一步的工作来定义开发中的这些监管层次结构 多样化阀门结构的维护与保养。因此，体外禽瓣细胞实验将 用于确定 ERK1/2 和巩膜功能改变对谱系的影响 瓣膜前体和成熟瓣膜细胞的分化。此外，生成的小鼠具有条件 体内巩膜功能的丧失将决定巩膜形成和瓣膜的要求 功能。该项目的具体目标是： 1. 确定 ERK1/2 和 ERK1/2 是否拮抗 Smad1/5/8 信号调节瓣膜前体细胞命运，促进肌腱或肌腱的分化 软骨样细胞类型。 2. 确定巩膜对于促进腱样细胞是否是必要且充分的 瓣膜前体细胞的分化并维持成熟瓣膜的细胞外基质组织 结构。 3. 确定肌腱样细胞分化和形成是否需要巩膜 支持体内瓣膜结构。检验这一假设将确定分子机制 对于正常的阀门开发和维护很重要。此外，拟议的研究将确定 可能导致先天性瓣膜疾病和成人瓣膜退化的调节相互作用 与结缔组织成分和分布的改变有关。项目叙述 在美国至少有 500 万人患有心脏瓣膜缺陷，瓣膜的发病率 由于修复或更换畸形瓣膜的外科手术超过 95,0000 次，疾病不断增加 2003 年在美国进行。然而，目前的阀门替代品是有限的，而且往往是暂时的，因为 无法生长、改造、修复或承受终生需求的不适当的替代品。增加 了解阀门开发和维护所需的流程具有潜在的临床价值 在识别与先天性心脏病和成人瓣膜退化相关的基因方面具有重要意义， 以及推进当前的治疗应用。