Role of Egfl7 in Vascular Development and Angiogenesis

Egfl7 在血管发育和血管生成中的作用

• 批准号: 7625067
• 负责人: Heidi Stuhlmann
• 金额: $ 40.45万
• 依托单位: WEILL MEDICAL COLL OF CORNELL UNIV
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-07-01 至 2012-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7625067
• 关键词: Adult; Agonist; Alleles; Aorta; Arterial Injury; Arteriovenous malformation; Binding; Biological Models; Blood Island; Blood Vessels; Collagen; Complex; Defect; Development; EGF gene; Embryo; Endothelial Cells; Endothelium; Ephrins; Genes; Growth Factor; Human; In Vitro; Knock-out; Lead; Ligands; Mediating; Mus; Mutation; Notch Signaling Pathway; Pathway interactions; Phase; Phenocopy; Process; Proteins; Repression; Research Personnel; Role; Signal Pathway; Signal Transduction; Small Interfering RNA; Staging; Stem cells; Subfamily lentivirinae; System; Testing; Transforming Growth Factor beta; Transgenic Mice; Vascular Endothelial Growth Factors; Vascular System; Veins; Venous; Yolk Sac; angiogenesis; base; cadherin 5; chorioallantoic membrane; embryonic stem cell; gain of function; knock-down; loss of function; membrane model; mutant; notch protein; novel; overexpression; progenitor; promoter; receptor; vasculogenesis

DESCRIPTION (provided by applicant): Vasculogenesis and angiogenesis are controlled by a complex system of growth factors and their cognate receptors. These include VEGF/VEGFR and angiopoietin/Tie signaling pathways, as well as b-FGF, TGF-beta, ephrins, and their receptors. In addition, the importance of Notch signaling for vascular development and arterial-venous fate specification has been elucidated. While the importance of these pathways for vascular development has been documented, it is likely that other critical factors remain unidentified. Using a "gene trap" approach, we recently identified Egfl7, a novel endothelial-restricted gene that encodes a secreted protein with an EMI domain, two EGF domains, and a putative DSL domain found in Notch ligands. Egfl7 is specifically expressed in the emerging vasculature and its progenitors in the yolk sac blood islands. In adults, Egfl7 is up-regulated during angiogenesis and arterial injury. Our preliminary studies indicate that EGFL7 binds to Notch 1 and 4 in vitro and mediates several of the known Notch effector functions. In the present proposal, we will test the hypothesis that EGFL7 is a novel ligand for Notch, that EGFL7 functions as a Notch agonist, and that EGFL7-induced Notch signaling mediates distinctive and non-redundant processes during vascular development and angiogenesis. We will test these hypotheses in primary human endothelial cells, and by using gain- and loss-of-function approaches in an ES cell in vitro differentiation system and in mice. We are proposing the following aims: Aim 1: Determine the role of EGFL7 in Notch signaling in HUVEC and in a chick chorioallantoic membrane model. Aim 2: Determine whether overexpression of Egfl7 in the endothelium leads to defects in vascular development. We will force expression of Egfl7 in endothelial cells by generating Tie2-Egfl7 transgenic mice, and induce Egfl7 expression in endothelial cells by generating VE-Cadherin:tTA;TRE-Egfl7 transgenic mice. Aim 3: Test whether Egfl7 function is crucial for early stages of vascular development. We will generate mice with a conditional knock-out allele and lentivirus-based siRNA knock-down in ES cells and mouse embryos.

描述（由申请人提供）：血管发生和血管生成由生长因子及其同源受体的复杂系统控制。这些包括VEGF/VEGFR和血管生成素/Tie信号传导途径，以及b-FGF、TGF-β、肝配蛋白及其受体。此外，Notch信号传导对血管发育和动脉-静脉命运特化的重要性已被阐明。虽然这些途径对血管发育的重要性已被证明，但其他关键因素可能仍未确定。使用“基因陷阱”的方法，我们最近确定了Egfl 7，一种新的内皮限制性基因，编码分泌蛋白的EMI结构域，两个EGF结构域，和一个假定的DSL结构域中发现的Notch配体。egfl 7在卵黄囊血岛中的新生血管系统及其祖细胞中特异性表达。在成人中，Egfl 7在血管生成和动脉损伤期间上调。我们的初步研究表明，EGFL 7在体外与Notch 1和4结合，并介导几种已知的Notch效应子功能。在本提案中，我们将测试EGFL 7是Notch的新配体，EGFL 7作为Notch激动剂发挥作用，EGFL 7诱导的Notch信号传导介导血管发育和血管生成过程中独特的非冗余过程的假设。我们将在原代人内皮细胞中测试这些假设，并通过在ES细胞体外分化系统和小鼠中使用功能获得和丧失的方法。我们提出以下目标：目标1：确定EGFL 7在HUVEC和鸡绒毛尿囊膜模型中Notch信号传导中的作用。目的2：确定内皮中Egfl 7的过表达是否导致血管发育缺陷。我们将通过产生Tie 2-Egfl 7转基因小鼠来迫使Egfl 7在内皮细胞中表达，并通过产生VE-钙粘蛋白：tTA; TRE-Egfl 7转基因小鼠来诱导Egfl 7在内皮细胞中表达。目的3：测试Egfl 7功能是否对血管发育的早期阶段至关重要。我们将在ES细胞和小鼠胚胎中产生具有条件性敲除等位基因和基于慢病毒的siRNA敲低的小鼠。