Developing vision: Wnts in programmed vessel regression

发展视力：程序化血管回归中的 Wnts

• 批准号: 6808963
• 负责人: Richard A. Lang
• 金额: $ 37.25万
• 依托单位: CINCINNATI CHILDRENS HOSP MED CTR
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-09-23 至 2009-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6808963
• 关键词: angiopoietins; apoptosis; biological signal transduction; cell cell interaction; cell cycle; cell growth regulation; developmental genetics; eye circulation; gene expression; gene interaction; gene targeting; genetic regulation; genetically modified animals; histogenesis; laboratory mouse; low density lipoprotein receptor; macrophage; phenotype; protein structure function; protooncogene; vascular endothelium; vision

DESCRIPTION (provided by applicant): The goal of this proposal is an understanding of the role of Wnt signaling in regression of the temporary vascular networks of the eye. This work has important implications for therapies aimed at ocular vascular disease, including retinopathy of prematurity and diabetic retinopathy, but also has broader implications for the treatment of many diseases that might be alleviated through pro- or anti-vascular therapy. The eye is ideally suited as a focus for this analysis: it is one of the few structures where vascular networks can readily be examined in their entirety unobstructed by surrounding cells, and where (in rodents) a programmed vascular regression occurs postnatally. Indeed, the eye is one of the few organs in which this analysis could reasonably be executed. We will execute three specific aims: Aim 1: Is cell-cycle progression required for endothelial cell (EC) death? Preliminary Results and prior work suggest that EC apoptosis may depend upon Wnt-stimulated entry to the cell cycle and transit through the so-called Restriction Point in mid-G1 phase. We will test this hypothesis by first assessing the cell cycle characteristics of Wnt responsive cells (1.1) and then determining whether imposition of a cell cycle arrest also prevents cell death (1.2). Aim 2: How are Angiopoietin and Wnt signaling integrated in programmed vascular regression? The strong genetic interaction between Ang2 and Lrp5 mutations in vascular regression suggests that Tie2 and Wnt signaling are closely integrated. We will test this hypothesis by determining whether Ang2 is a Transcriptional target of the Wnt pathway (2.1), by determining whether Wnt signaling is modified in the absence of Lrp5, or Ang2 (2.2) and by injecting recombinant Wnt agonists and antagonists (2.3). Aim 3: Do macrophages kill ECs by producing Wnt ligands? Preliminary evidence suggest that macrophages drive programmed regression by producing Wnt ligands. We will test this possibility directly by asking whether macrophage absence down-modulates EC Wnt responses (3.1), by determining which Wnt ligands are expressed by macrophages (3.2), and by obtaining existing, or generating new Wnt ligand nullmice for phenotypic analysis (3.3). Completion of this work will provide important information on how the Wnt and Angiopoietin signaling pathways interact and furthermore, will indicate how we might modulate these signaling pathways in an effort to treat vascular diseases of the eye and other organs.

描述（由申请人提供）：该提案的目的是了解Wnt信号在眼睛临时血管网络回归中的作用。这项工作对针对眼血管疾病的疗法具有重要意义，包括早产性和糖尿病性视网膜病变的视网膜病变，但对许多可能通过亲血或抗血管疗法来缓解的疾病的治疗也具有更大的影响。理想的眼睛是该分析的重点：它是可以轻易通过周围细胞毫无障碍的血管网络进行检查的少数结构之一，而（在啮齿动物中）在后产后发生了（啮齿动物）的血管回归。确实，眼睛是可以合理执行该分析的少数器官之一。 我们将执行三个具体目标：目标1：内皮细胞（EC）死亡需要细胞周期进展吗？初步结果和先前的工作表明，EC凋亡可能取决于Wnt刺激的细胞周期进入，并在G1中期通过所谓的限制点过境。我们将通过首先评估Wnt响应细胞的细胞周期特征（1.1），然后确定施加细胞周期停滞是否也阻止细胞死亡（1.2）来检验该假设（1.1）。 AIM 2：血管生成素和Wnt信号如何整合到编程的血管回归中？血管回归中ANG2和LRP5突变之间的强遗传相互作用表明TIE2和WNT信号是密切相结合的。我们将通过确定ANG2是否是Wnt途径的转录靶标（2.1），通过确定是否在不存在LRP5或ANG2（2.2）的情况下修改Wnt信号传导以及通过注入重组Wnt Wnt激动剂和拮抗剂（2.3）来检验该假设。目标3：巨噬细胞是否通过产生Wnt配体杀死EC？初步证据表明，巨噬细胞通过产生Wnt配体来驱动编程的回归。我们将直接询问巨噬细胞的缺失是通过确定巨噬细胞（3.2）表达哪些Wnt配体的巨噬细胞响应（3.1），以及通过获得现有的或产生新的Wnt Nullmice进行表型分析（3.3）来表达的（3.2）。这项工作的完成将提供有关Wnt和血管生成素信号通路如何相互作用和此外的重要信息，这将指示我们如何调节这些信号通路以治疗眼睛和其他器官的血管疾病。