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: 7333806
• 负责人: Heidi Stuhlmann
• 金额: $ 43.36万
• 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 2010-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7333806
• 关键词: angiogenesis; angiopoietins; cadherins; cell surface receptors; chick embryo; developmental genetics; epidermal growth factor; genetic screening; genetically modified animals; histogenesis; laboratory mouse; mammalian embryology; protein structure function; receptor binding; tissue /cell culture; transcription factor; vascular endothelium

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）：血管生成和血管生成由复杂的生长因子及其同源受体控制。其中包括VEGF/VEGFR和血管生成素/TIE信号通路，以及B-FGF，TGF-β，Ephrins及其受体。另外，已经阐明了Notch信号传导对血管发育和动脉命运规范的重要性。尽管已经记录了这些途径在血管发育中的重要性，但其他关键因素可能仍然不明。使用“基因陷阱”方法，我们最近确定了EGFL7，这是一种新型的内皮限制基因，该基因编码具有EMI结构域的分泌蛋白，两个EGF结构域，以及在Notch配体中发现的假定DSL结构域。 EGFL7在新兴的脉管系统及其祖细胞中特别表达。在成年人中，EGFL7在血管生成和动脉损伤过程中被上调。我们的初步研究表明，EGFL7在体外与Notch 1和4结合，并介导了几种已知的Notch效应子函数。在本提案中，我们将检验以下假设：EGFL7是Notch的一种新型配体，EGFL7是Notch激动剂，并且EGFL7诱导的Notch信号传导在血管发育和血管生成过程中介导了独特的和非冗余的过程。我们将在原代人内皮细胞中检验这些假设，并通过在ES细胞中使用功能和功能丧失方法在体外分化系统和小鼠中使用功能丧失方法。我们提出以下目的：目标1：确定EGFL7在HUVEC和小鸡绒毛膜模型中的Notch信号传导中的作用。目标2：确定内皮中EGFL7的过表达是否会导致血管发育中的缺陷。我们将通过产生TIE2-EGFL7转基因小鼠在内皮细胞中迫使EGFL7表达，并通过产生VE-钙粘蛋白：TTA; TRE-EGFL7转基因小鼠在内皮细胞中诱导EGFL7表达。 AIM 3：测试EGFL7功能是否对于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带有条件敲除等位基因的小鼠和基于慢病毒的siRNA敲除。