Competition and morphogenesis in tip cell-mediated branching of tubular networks

尖端细胞介导的管状网络分支的竞争和形态发生

• 批准号: 8961763
• 负责人: AMIN S GHABRIAL
• 金额: $ 32.2万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-07-01 至 2019-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8961763
• 关键词: Address; Adherens Junction; Animals; Apical; Blood; Blood flow; Cavernous Malformation; Cell Nucleus; Cell physiology; Cells; Cerebrum; Collaborations; Coupled; Cyst; Data; Defect; Development; Drosophila genus; Employee Strikes; Endothelial Cells; Environment; Fibroblast Growth Factor; Fibroblast Growth Factor Receptors; Filopodia; Gases; Genes; Genetic; Goals; Grant; Growth; Human; Image; Imaging Device; Lead; Legal patent; Life; Logic; Mediating; Microtubules; Modeling; Molecular; Molecular Genetics; Morphogenesis; Mutation; Organ; Orthologous Gene; Output; Pathway interactions; Play; Positioning Attribute; Process; Proteins; Publications; Publishing; Receptor Activation; Receptor Signaling; Regulation; Reporting; Resolution; Role; Septate; Serum Response Factor; Shapes; Side; Signal Transduction; Site; Staging; Stereotyping; System; Testing; Tissues; Trachea; Tube; Tubular formation; Twin Multiple Birth; Vascular Diseases; Vascular Endothelial Growth Factors; Vascular System; Vesicle; Work; Zebrafish; Zinc Fingers; angiogenesis; apical membrane; base; basolateral membrane; follow-up; gain of function; genetic analysis; human disease; in vivo; innovation; migration; moesin; mutant; novel; optogenetics; programs; public health relevance; respiratory; response; trafficking; transcription factor; unpublished works

 DESCRIPTION (provided by applicant): In sprouting angiogenesis, endothelial cells from a pre-existing tube are led by actively migrating "tip cells" to form new vessels. In the Drosophila respiratory organ (tracheal system), primary branching is also led by tip cells. Work from us and others showed that tip cells in both systems are selected through a competition-based mechanism. In both models of branch sprouting, the tip cells are morphologically distinct, extending filopodia to sense the local environment and to lead migration up a concentration gradient of a branch-inducing signal. Subsequent to initiating and guiding the outgrowth of a new branch, tip cells execute a second essential function: they must form a tube (lumenize) in order to make the new branch functional. Tip cells hollow out to form "seamless" tubes that lack junctional "seams" (adherens junctions and tight/septate junctions). In the Drosophila tracheal system, all tip cells reside in stereotyped positions and form seamless tubes; furthermore, tracheal terminal cells form new seamless tube side branches throughout the course of larval life. These qualities, combined with the power of genetic analysis in Drosophila, have made tracheal terminal cells an exceptionally useful model for dissecting seamless tube morphogenesis. Tip cell tube formation is critical, as it permits transport of blood or gas throug the cell; however, despite or recent progress (4 major publications in the last grant cycle), important questions remain: how does FGFR- signaling trigger distinct outputs at each stage? how does FGFR induce seamless tubes? how does FGFR regulate seamless tube branching? what are the effectors regulated downstream of FGFR? We propose to exploit or published and preliminary data to address these questions using innovative approaches. With the twin goals of understanding how signaling is coupled to changes in the mechanism of tubulogenesis, and how the seamless tubulogenesis machinery operates downstream of FGFR, we propose the following specific aims: Aim 1: Determine how FGFR activation induces seamless tubulogenesis. We will focus our studies of seamless tubulogenesis on the novel zinc finger transcription factor that we identify, in our preliminary data, as essential for seamless tube morphogenesis. Aim 2: Determine how FGFR activation regulates local branching of the seamless tube. We will focus on characterization of seamless tube branching using innovative optogenetic and live imaging tools. We will follow up on our preliminary data to establish the roles of three proteins - PALS2/MPP6/2 (Drosophila Varicose), Spectroplakin (Drosophila Short stop) and Moesin - in seamless tube branching in Drosophila and in the zebrafish vascular system. Completion of these specific aims will represent a dramatic advance in the field, connecting signal transduction to the cellular machinery of tube morphogenesis at an unprecedented level of resolution.

 描述(申请人提供)：在萌芽的血管生成过程中，来自预先存在的管子的内皮细胞被积极迁移的“尖端细胞”引导形成新的血管。在果蝇的呼吸器官(气管系统)中，初级分支也是由尖端细胞领导的。我们和其他人的研究表明，两个系统中的TIP细胞都是通过基于竞争的机制选择的。在两种分枝萌发模式中，顶端细胞在形态上是不同的，延伸丝状足细胞来感知局部环境，并引导沿分枝诱导信号的浓度梯度向上迁移。在启动和引导新枝的生长之后，顶端细胞执行第二个基本功能：它们必须形成一个管状(管状化)，以使新枝发挥作用。顶端细胞被掏空，形成“无缝”的管子，没有连接的“接缝”(粘连的连接和紧密的/分隔的连接)。在果蝇的气管系统中，所有的顶端细胞都固定在固定的位置，形成无缝的管状结构；此外，在整个幼虫的生命过程中，气管末端细胞形成新的无缝管状侧支。这些特性，再加上果蝇的遗传分析能力，使气管末端细胞成为解剖无缝管形态发生的一个特别有用的模型。TIP细胞管的形成是至关重要的，因为它允许血液或气体通过细胞运输；然而，尽管或最近取得了进展(在上一个赠款周期中有4篇主要出版物)，重要的问题仍然存在：FGFR信号如何在每个阶段触发不同的输出？FGFR是如何产生无缝管的？FGFR如何规范无缝管分支？FGFR下游受调控的效应物是什么？我们建议利用或公布初步数据，以创新的方法解决这些问题。为了了解信号如何与小管发生机制的变化相耦合，以及无缝小管发生机制是如何在FGFR下游运行的，我们提出了以下具体目标：目标1：确定FGFR激活如何诱导无缝小管发生。我们将把我们对无缝小管发生的研究集中在新的锌指转录因子上，在我们的初步数据中，我们发现它对无缝小管的形态发生是必不可少的。目的2：确定FGFR激活如何调节无缝管的局部分支。我们将专注于使用创新的光遗传和实时成像工具来表征无缝管分支。我们将根据我们的初步数据来确定三种蛋白-PALS2/MPP6/2(果蝇Varicose)、Spectrplakin(果蝇短停顿)和Moesin-在果蝇无缝管分支和斑马鱼血管系统中的作用。这些特定目标的完成将代表着该领域的巨大进步，将信号转导与管形态发生的细胞机制以前所未有的分辨率连接起来。