Flt4 signaling in vascular and lymphatic development

Flt4 信号在血管和淋巴管发育中的作用

• 批准号: 8974787
• 负责人: NATHAN D LAWSON
• 金额: $ 41.88万
• 依托单位: UNIV OF MASSACHUSETTS MED SCH WORCESTER
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-11-24 至 2018-10-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8974787
• 关键词: Address; Automobile Driving; Biological Models; Blood; Blood Vessels; Cardiovascular system; Cell Line; Cells; Chromatin; Collaborations; Cytoplasmic Tail; Data; Defect; Development; Embryo; Embryonic Development; Endocrine system; Endothelial Cells; Enhancers; Erythrocytes; Exhibits; FLT4 gene; Fibroblast Growth Factor Receptors; Genes; Genetic; Genome; Growth; Health; Hormones; Human; Human Development; Immune; Indium; Intercellular Fluid; Investigation; Knock-out; Knowledge; Ligand Binding; Lipids; Lymphatic; Lymphatic Endothelial Cells; Lymphatic System; Lymphatic vessel; Lymphedema; Lymphoid Cell; Mediating; Modeling; Mus; Mutate; Mutation; Output; Oxygen; Pathway interactions; Pattern; Phenotype; Platelet-Derived Growth Factor Receptor; Play; Receptor Protein-Tyrosine Kinases; Role; Signal Transduction; Signaling Molecule; Site; System; Techniques; Transcript; Transgenic Organisms; Tyrosine; Vascular Endothelial Growth Factor Receptor-3; Vascular Endothelial Growth Factors; Vascular System; Veins; Venous; Zebrafish; absorption; angiogenesis; blind; cell type; gastrointestinal system; in vivo; insight; mutant; notch protein; nuclease; progenitor; receptor; transcription factor

DESCRIPTION (provided by applicant): The circulatory system consists of endothelial cell-lined blood vessels that serve as a transport network for red blood cells, which carry oxygen, immune cells, and hormones of the endocrine system. In parallel, the lymphatic system comprises blind-ended vessels, which are similarly lined by endothelial cells and are closely associated with the blood vessels of the circulatory system. Lymphatic vessels collect and return interstitial fluid to the circulatory system, are a site of lymphoid cell development and transit, and are required for lipid absorption in the digestive system. In both systems, the primary cell type that initiates formation and mediates function is the endothelial cell. Interestingly, lymphatic endothelial cells derive from venous endothelial cells during embryonic development indicating a common origin for both vessel types. Not surprisingly, a number of signaling molecules are shared and required for the formation of the circulatory and lymphatic systems. Among these is Flt4, a receptor tyrosine kinase expressed on both vascular and lymphatic endothelial cells that binds the ligand vascular endothelial growth factor c (Vegfc). Loss of Flt4 function in mouse or zebrafish embryos leads to a range of defects in veins, angiogenic blood vessels, and lymphatic vessels. This diverse requirement for Flt4 is governed, in part, by its highly dynamic expression during embryonic development. However, little is known about upstream regulators responsible for dynamic expression. An additional aspect of the dynamic role of Flt4 is its ability to activate a wide range of downstream signaling effectors in endothelial cells. Studies in primary cell lines and in vivo suggest that distinct downstream effectors may play context dependent roles during embryonic vascular and lymphatic development. Given the importance of new blood and lymphatic vessel growth in both human development and pathological settings, a better understanding of how Flt4 signals is highly relevant. In this application we will rely on our expertise using the zebrafish as a model to address these issues. In Aim 1, we will determine what controls dynamic expression of flt4. In particular, we will investigate the role of ERK and Ets transcription factors in directly activatin enhancers at the flt4 locus to induce tip cell expression. This will be achieved through application of transgenic and knockout zebrafish lines. In Aim 2, we will determine which Flt4-proximal signaling outputs are essential for vascular and lymphatic development. This will be done through application of site-specific nucleases to generate zebrafish lines bearing targeted deletion of tyrosines in the Flt4 cytoplasmic domain. Analysis of these lines will allow us to determine the importance of different downstream effectors in mediating context-dependent roles of Flt4.

描述（由申请人提供）：循环系统由内皮细胞衬里的血管组成，这些血管充当红细胞的传输网络，后者携带氧气，免疫细胞和内分泌系统的激素。同时，淋巴系统包含盲血管，这些血管与内皮细胞相似，与循环系统的血管紧密相关。淋巴管收集并返回间质流体到循环系统，是淋巴样细胞发育和转运的部位，是消化系统中脂质吸收所必需的。在这两个系统中，启动形成和介导功能的主要细胞类型是内皮细胞。有趣的是，淋巴内皮细胞在胚胎发育过程中衍生出静脉内皮细胞，表明两种血管类型的共同起源。毫不奇怪，形成循环系统和淋巴系统所需的许多信号分子。其中包括FLT4，是在结合配体血管内皮生长因子C（VEGFC）的血管和淋巴内皮细胞上表达的受体酪氨酸激酶。小鼠或斑马鱼胚胎中FLT4功能的丧失导致静脉，血管生成血管和淋巴管中的一系列缺陷。这种对FLT4的多种要求部分由其在胚胎发育过程中高度动态的表达来控制。但是，关于负责动态表达的上游调节剂知之甚少。 FLT4动态作用的另一个方面是它可以激活内皮细胞中各种下游信号效应子的能力。在原始细胞系和体内的研究表明，在胚胎血管和淋巴发育过程中，不同的下游效应子可能在依赖上下文的作用。鉴于新的血液和淋巴管生长在人类发育和病理环境中的重要性，因此可以更好地理解FLT4信号如何高度相关。在此应用程序中，我们将依靠使用斑马鱼作为模型来解决这些问题的专业知识。在AIM 1中，我们将确定哪些控制FLT4的动态表达。特别是，我们将研究ERK和ETS转录因子在FLT4基因座直接激活蛋白增强子中的作用，以诱导尖端细胞的表达。这将通过应用转基因和敲除斑马鱼线来实现。在AIM 2中，我们将确定哪些FLT4-Proximal信号输出对于血管和淋巴发育至关重要。这将通过应用位点特异性核酸酶来产生斑马鱼线，这些斑马鱼在FLT4细胞质结构域中具有靶向缺失的酪氨酸。对这些线的分析将使我们能够确定不同下游效应子在介导FLT4的上下文依赖性作用中的重要性。