Fox genes in arterial-venous endothelial cell identity

Fox基因在动静脉内皮细胞身份中的作用

• 批准号: 6776121
• 负责人: Tsutomu Kume
• 金额: $ 33.98万
• 依托单位: VANDERBILT UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-04-01 至 2008-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6776121
• 关键词: angiogenesis; artery; biological signal transduction; cell differentiation; developmental genetics; gel mobility shift assay; gene expression; gene targeting; genetic regulation; genetically modified animals; integrase; laboratory mouse; microarray technology; tissue /cell culture; transcription factor; vascular endothelial growth factors; vascular endothelium; veins

DESCRIPTION (provided by applicant): Arteries and veins are anatomically distinct within the adult circulatory system, and it was previously thought that the differentiated identities of arterial and venous endothelial cells arose in response to hemodynamic forces such as blood pressure and the direction of blood flow. However, recent evidence suggests that the specification/differentiation of arteries and veins is governed by genetic mechanisms before the active onset of circulation. This event occurs before remodeling of blood vessels, and impaired specification/differentiation of arteries and veins leads to failure to remodel blood vessels. Although it has been shown that several signaling systems such as the VEGF, Notch, and ephrin signaling pathways are involved in this process, molecular mechanisms of how transcription factors function to regulate expression of such genes remain to be elucidated. We have previously shown that the two genes encoding closely related Fox transcription factors, Foxc1 and Foxc2, are expressed in overlapping populations of cells contributing to the endothelial and mesenchymal cells of the blood vessels. Embryos lacking either Foxc1 or Foxc2, and most compound heterozygotes, die pre or perinatally with similar abnormal phenotypes, including defects in the cardiovascular system. Compound Foxc1; Foxc2 homozygotes die earlier and with much more severe defects than single homozygotes alone. Most importantly, compound homozygotes have arteriovenous malformations and the failure of blood vessels to remodel, and in the endothelial cells of compound homozygotes Notch signaling genes and ephrinB2 are downregulated. These data lead to the central hypothesis that Foxc1 and Foxc2 play dose-dependent, interactive roles in the process of arterial-venous cell fate determination/differentiation. One of the goals of this grant is to test whether Foxc proteins act downstream of VEGF signaling to regulate arterial-venous identity (Aim 1). The proposed hypothesis will be tested by (a) analyzing conditional compound mutants of Foxc1 and Foxc2 in endothelial cells crossed with Tie2-Cre mice and (b) rescue experiments in which Tie2-Foxc transgenic mice are crossed with compound Foxcl; Foxc2 mutants (Aims 2). Finally, direct target gene(s) regulated by Foxc1 and Foxc2 in the process of specification/differentiation of arteries and veins will be identified (Aim 3). Elucidating the molecular mechanisms of how Foxcl/c2 function during vascular development will significantly contribute to our knowledge of how genes cooperate to control mammalian cardiovascular development and will lead to a better understanding of human congenital defects.

描述（由申请人提供）：成人循环系统中的动脉和静脉在解剖学上是不同的，以前认为动脉和静脉内皮细胞的差异身份是响应血流动力学力（例如血压和血流方向）而产生的。然而，最近的证据表明，动脉和静脉的规格/分化在循环活跃开始之前受到遗传机制的控制。该事件发生在血管重塑之前，并且动脉和静脉的规范/分化受损导致血管重塑失败。尽管已经表明，VEGF、Notch 和 ephrin 信号通路等多种信号系统参与了这一过程，但转录因子如何发挥作用来调节此类基因表达的分子机制仍有待阐明。我们之前已经证明，编码密切相关的 Fox 转录因子 Foxc1 和 Foxc2 的两个基因在血管内皮细胞和间充质细胞的重叠细胞群中表达。缺乏 Foxc1 或 Foxc2 的胚胎以及大多数复合杂合子会在产​​前或围产期死亡，并具有类似的异常表型，包括心血管系统缺陷。化合物Foxc1； Foxc2 纯合子比单一纯合子更早死亡，并且具有更严重的缺陷。最重要的是，复合纯合子存在动静脉畸形和血管重塑失败，并且在复合纯合子的内皮细胞中Notch信号基因和ephrinB2下调。这些数据得出了一个中心假设：Foxc1 和 Foxc2 在动静脉细胞命运决定/分化过程中发挥剂量依赖性、相互作用的作用。该资助的目标之一是测试 Foxc 蛋白是否在 VEGF 信号下游发挥作用来调节动静脉特性（目标 1）。所提出的假设将通过以下方式进行检验：(a) 分析与 Tie2-Cre 小鼠杂交的内皮细胞中 Foxc1 和 Foxc2 的条件化合物突变体；(b) Tie2-Foxc 转基因小鼠与化合物 Foxcl 杂交的拯救实验； Foxc2 突变体（目标 2）。最后，将鉴定在动脉和静脉的分化/分化过程中受Foxc1和Foxc2调节的直接靶基因（目标3）。阐明 Foxcl/c2 在血管发育过程中如何发挥作用的分子机制将极大地有助于我们了解基因如何合作控制哺乳动物心血管发育，并将导致更好地了解人类先天缺陷。