Hyaluronan and atrioventricular canal morphogenesis

透明质酸和房室管形态发生

• 批准号: 6493624
• 负责人: JOHN W MCDONALD
• 金额: $ 28.8万
• 依托单位: UNIVERSITY OF ARIZONA
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-08-01 至 2002-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6493624
• 关键词: biological signal transduction; cell adhesion; cell adhesion molecules; cell differentiation; cell migration; developmental genetics; embryo /fetus; embryogenesis; endocardium; epithelium; extracellular matrix; gene expression; genetic regulatory element; genetically modified animals; glucuronosyltransferase; guanine nucleotide binding protein; heart valves; histogenesis; hyaluronate; laboratory mouse; mesenchyme; myocardium; vertebrate embryology

The acellular cardiac jelly matrix that separates the myocardium and endocardium in the primitive heart forms endocardial cushion swellings in two regions of the heart, the atrioventricular (AV) canal and the outflow tract. As development proceeds, a population of the endothelial cells lining the cushions undergoes an epithelial to mesenchymal transformation under the influence of myocardial-derived stimuli. Resultant migratory mesenchymal cells invade the cushion matrix to become cardiac valve precursors. Molecular genetic studies in the mouse demonstrate that both myaluronan (HA) and versican are required for formation on the cardiac cushions. Animals lacking these matrix molecules versican are required for formation of the cardiac cushions. Animals lacking these matrix molecules the compelling evidence for the role of the extracellular matrix in endocardial cushion formation, it is unclear if matrix molecules actively participate in the formation of valve structures or in the matrix provides only a supportive environment for cellular migration and differentiation. We hypothesize that HA plays two roles in AV canal morphogenesis: a) By binding to other matrix components (versican, and type VI collagen) and thus forming a structural component of the cardiac jelly and b) By signaling via a cell surface receptor-mediated mechanism upstream of Ras. Experiments are designed to examine the function and regulation of HA in each of these proposed capacities. The specific aims are: 1. Characterize the developmental expression patterns for the principal source of HA during heart development, hyaluronan synthase-2 (Has2). In addition, define the expression of molecular markers of cushion morphogenesis in mouse and chick endocardial cushions using an in vitro collagen gel transformation assay to establish the applicability of this assay for the mammalian AV canal. 2. Determine the functional role of HA during in vitro endocardial cushion morphogenesis. 3. Characterize the cis regulatory elements of the Has2 gene that are responsible for expression in the cardiac cushions. Taken together, these studies will provide a greater understanding of the biologic role of the extracellular matrix in the developing heart and provide unique reagents and techniques for future analysis of AV canal morphogenesis.

在原始心脏中分隔心肌和心内膜的无细胞心脏胶基质在心脏的两个区域（房室管和流出道）形成心内膜垫肿胀。随着发育的进行，衬垫内衬的内皮细胞群在心肌源性刺激的影响下经历上皮细胞向间质细胞的转化。由此产生的迁移间充质细胞侵入垫基质，成为心脏瓣膜前体。小鼠的分子遗传学研究表明，肌醛酸 (HA) 和多功能蛋白聚糖都是心脏垫形成所必需的。缺乏这些多功能蛋白聚糖基质分子的动物是形成心脏垫所必需的。缺乏这些基质分子的动物是细胞外基质在心内膜垫形成中的作用的令人信服的证据，目前尚不清楚基质分子是否积极参与瓣膜结构的形成或基质中仅为细胞迁移和分化提供支持性环境。我们假设 HA 在 AV 管形态发生中发挥两个作用：a) 通过与其他基质成分（多功能蛋白聚糖和 VI 型胶原蛋白）结合，从而形成心肌胶的结构成分；b) 通过细胞表面受体介导的信号传导Ras 上游的机制。实验旨在检查 HA 在每种拟议功能中的功能和调节。具体目标是： 1. 表征心脏发育过程中 HA 主要来源乙酰透明质酸合酶 2 (Has2) 的发育表达模式。此外，使用体外胶原凝胶转化测定来定义小鼠和鸡心内膜垫中垫形态发生的分子标记的表达，以确定该测定对于哺乳动物 AV 管的适用性。 2.确定HA在体外心内膜垫形态发生过程中的功能作用。 3. 表征负责在心脏垫中表达的 Has2 基因的顺式调控元件。总而言之，这些研究将有助于更好地了解细胞外基质在心脏发育中的生物学作用，并为未来分析 AV 管形态发生提供独特的试剂和技术。