Alk1 regulation of embryonic angiogenesis

Alk1 调控胚胎血管生成

• 批准号: 6858077
• 负责人: BETH L ROMAN
• 金额: $ 38.8万
• 依托单位: GEORGETOWN UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-04-01 至 2009-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6858077
• 关键词: angiogenesis; biological signal transduction; blood circulation; confocal scanning microscopy; embryology; gene expression; gene expression profiling; growth factor receptors; immunocytochemistry; shear stress; telangiectasia; tissue /cell culture; transforming growth factors; zebrafish

DESCRIPTION (provided by applicant): Homozygous inactivation of the endothelial-specific TGFB type I receptor, Alk1, results in embryonic lethality stemming from vascular malformations, and heterozygous inactivation results in a potentially lethal human vascular dysplasia, hereditary hemorrhagic telangiectasia type 2 (HHT2). Clearly, AIk1 plays a necessary role in building and maintaining the vertebrate vasculature; however, the nature of that role is currently unclear. The objective of this proposal is to use the accessible zebrafish embryo, which has a well described, stereotypical vertebrate vasculature, to define the effects of Alkl activation on endothelial cell functional state and transcript expression. Specific Aim 1 comprises experiments designed to test the hypothesis that TGFB signaling through Alk1 is required for angiogenic resolution. Studies in support of this Aim will include time lapse confocal analysis of endothelial sprouting and proliferation in violet beauregarde (vbg) mutants, which harbor a mutation in alk1; and assessment of endothelial migration, proliferation, sprouting, and basement membrane formation in zebrafish embryos overexpressing dominant negative and/or constitutively active forms of alk1, alk5 (the canonical TGFB type I receptor that reportedly competes with Alk1 in determining endothelial state), and tgfB within the endothelium. Specific Aim 2 comprises experiments designed to test the hypothesis that Alk1 is induced by shear stress and plays a role in vascular remodeling. The effect of blood flow on alk1 expression and remodeling of cranial vessels in zebrafish embryos will be determined, and the effect of shear stress on Alk1expression in cultured mammalian cells will be assessed. Further experiments will identify molecular components of the pathway that translates mechanical shear stress into Alk1 induction. Specific Aim 3 comprises experiments designed to identify downstream components of Alk1 signaling. Expression levels of genes reportedly regulated by constitutively active Alk1 in mammalian cell culture will be compared in vbg mutants and wild type siblings, and novel alkl-regulated genes will be sought by comparing the endothelial transcriptome in vbg mutants and wild type siblings. Taken together, the proposed experiments will determine whether Alk1 plays a role in angiogenic activation, resolution, and/or remodeling, and, with the definition of downstream targets, will promote a better understanding of the molecular pathways of normal vessel development and HHT2 pathogenesis.

DESCRIPTION (provided by applicant): Homozygous inactivation of the endothelial-specific TGFB type I receptor, Alk1, results in embryonic lethality stemming from vascular malformations, and heterozygous inactivation results in a potentially lethal human vascular dysplasia, hereditary hemorrhagic telangiectasia type 2 (HHT2).显然，AIK1在建造和维持脊椎动物脉管系统中起着必要的作用。但是，目前尚不清楚该角色的性质。该提案的目的是使用可访问的斑马鱼胚胎，该胚胎具有很好的描述，刻板的脊椎动物脉管系统来定义ALKL活化对内皮细胞功能状态和转录本表达的影响。特定目标1包括旨在测试假设的实验，即通过ALK1信号传导是血管生成分辨率所必需的。支持此目标的研究将包括对紫罗兰色Beauregarde（VBG）突变体中内皮发芽和增殖的及时共焦分析，这些突变体具有ALK1突变的突变；以及评估斑马鱼胚胎中内皮迁移，增殖，发芽和地下膜形成，过表达ALK1，ALK5的主动性负面和/或组成性活性形式（据报道，I型TGFB I型受体，据报道是与ALK1在确定内皮状态的ALK1竞争）和tgffb内部的，以及tgffb的内部。特定目标2包括旨在测试ALK1由剪切应力诱导并在血管重塑中起作用的假设的实验。将确定血流对斑马鱼胚胎中颅血管的ALK1表达和重塑的影响，并将评估剪切应力对剪切应力对培养的哺乳动物细胞中ALK1表达的影响。进一步的实验将确定将机械剪应力转化为ALK1诱导的途径的分子成分。特定目标3包括旨在识别ALK1信号传导下游组件的实验。据报道，在VBG突变体和野生型兄弟姐妹中，将比较由组成型活性ALK1调节的基因的表达水平，并通过比较VBG突变体和野生型兄弟姐妹中的内皮转录组中的内皮转录组来比较新颖的ALKL调节基因。综上所述，提出的实验将确定ALK1是否在血管生成，分辨率和/或重塑中起作用，并且通过定义下游靶标，将促进对正常血管发育和HHT2病原体的分子途径的更好理解。