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血管组成，作为红细胞的运输网络，红细胞携带氧气、免疫细胞和内分泌系统的激素。与此同时，淋巴系统包括盲端血管，这些血管同样排列有内皮细胞，并且与循环系统的血管密切相关。淋巴管收集间质液并将其返回循环系统，是淋巴细胞发育和转运的场所，并且是消化系统中脂质吸收所必需的。在这两个系统中，启动形成并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源自静脉内皮细胞，表明这两种血管类型具有共同的起源。毫不奇怪，许多信号分子是共享的，并且是循环和淋巴系统形成所必需的。其中包括 Flt4，一种在血管内皮细胞和淋巴管内皮细胞上表达的受体酪氨酸激酶，可与配体血管内皮生长因子 c (Vegfc) 结合。小鼠或斑马鱼胚胎中 Flt4 功能的丧失会导致静脉、血管生成血管和淋巴管的一系列缺陷。 Flt4 的这种多样化需求部分是由其在胚胎发育过程中的高度动态表达决定的。然而，我们对负责动态表达的上游调控因子知之甚少。 Flt4 动态作用的另一个方面是它能够激活内皮细胞中广泛的下游信号传导效应器。原代细胞系和体内研究表明，不同的下游效应器可能在胚胎血管和淋巴管发育过程中发挥环境依赖性作用。鉴于新血液和淋巴管生长在人类发育和病理环境中的重要性，更好地了解 Flt4 信号如何发挥作用非常重要。在此应用中，我们将依靠我们的专业知识，使用斑马鱼作为模型来解决这些问题。在目标 1 中，我们将确定控制 flt4 动态表达的因素。特别是，我们将研究 ERK 和 Ets 转录因子在直接激活 flt4 位点增强子以诱导尖端细胞表达中的作用。这将通过应用转基因和基因敲除斑马鱼品系来实现。在目标 2 中，我们将确定哪些 Flt4 近端信号输出对于血管和淋巴管发育至关重要。这将通过应用位点特异性核酸酶来产生 Flt4 细胞质结构域中酪氨酸的靶向删除的斑马鱼品系来完成。对这些细胞系的分析将使我们能够确定不同下游效应子在介导 Flt4 上下文依赖性作用中的重要性。