Angiopoietins in airway vascular leak and angiogenesis

描述（由申请人提供）：本项目将研究血管生成素对气道血管和淋巴管的不同作用，目的是了解气道炎症的潜在机制并开发新的治疗策略。我们最近的研究发现，有效的血管生成素在气道的行动开辟了新的方向，具有潜在的重要临床意义。血管生成素生长因子家族是正常血管发育所必需的，并通过内皮细胞中Tie 2酪氨酸激酶受体信号传导在气道病理生理学中发挥独特作用。血管生成素-1（Ang 1）激活Tie 2受体磷酸化，而血管生成素-2（Ang 2）抑制Ang 1作用或激活Tie 2信号传导，这取决于环境和局部时间和空间浓度。拟议的项目建立在当前资助期内气道血管生成素作用的研究结果的基础上，也受益于其他项目中慢性气道炎症和肿瘤中血管生成和淋巴管生成的补充研究。总的假设是Ang 1和Ang 2通过作用于血管内皮细胞和血管内皮细胞促进急性气道炎症向持续气道炎症的转变。这四个具体目的是：（1）确定Ang 1是否通过稳定内皮细胞连接或周细胞缔合来减少气道炎症中的血浆渗漏;（2）确定Ang 1诱导的血管重构对气道脉管系统对炎症刺激的反应性的影响;（3）确定Ang 1是否通过限制萌芽血管生成和血管退化来稳定气道脉管系统，以及Ang 2是否具有相反的作用;和（4）确定血管生成素是否促进淋巴管内皮细胞的重塑以及经由气道毛细血管的流体和细胞运输。计划的研究将使用正常、转基因和基因敲除小鼠气道血管生成和炎症的动物模型以及培养内皮细胞的体外研究的组合，以探索血管生成素对血管和淋巴管作用的细胞和分子机制。这些方法将利用新型血管生成素激动剂和拮抗剂作为重组蛋白或腺病毒载体，最先进的共聚焦显微镜成像和定量，以及生理和分子方法。通过阐明Ang 1的不同作用和Ang 2的相反或互补作用，减少血浆渗漏，限制萌芽血管生成，促进气道血管和淋巴管重塑，计划的研究将扩大开发未来几代哮喘，慢性支气管炎和其他炎症性气道疾病治疗的前景。

DESCRIPTION (provided by applicant): This project will examine the diverse actions of angiopoietins on airway blood vessels and lymphatic vessels with the goal of understanding underlying mechanisms of airway inflammation and developing new treatment strategies. Our recent findings of potent angiopoietin actions in airways have opened new directions with potentially important clinical implications. The angiopoietin growth factor family is essential for normal vascular development and plays a unique role in airway pathophysiology through Tie2 tyrosine kinase receptor signaling in endothelial cells. Angiopoietin-1 (Ang1) activates Tie2 receptor phosphorylation, whereas Angiopoietin-2 (Ang2) inhibits Ang1 actions or activates Tie2 signaling, depending on context and local temporal and spatial concentrations. The proposed project builds on results of studies of angiopoietin actions in airways during the current grant period and also benefits from complementary studies of angiogenesis and lymphangiogenesis in chronic airway inflammation and tumors in other projects. The overall hypothesis is that Ang1 and Ang2 facilitate the transition from acute to sustained airway inflammation through actions on endothelial cells of blood vessels and lymphatics. The four Specific Aims are to: (1) determine whether Ang1 reduces plasma leakage in airway inflammation by stabilizing endothelial cell junctions or pericyte associations; (2) determine the effect of Ang1-induced vascular remodeling on the responsiveness of airway vasculature to inflammatory stimuli; (3) determine whether Ang1 stabilizes the airway vasculature by limiting sprouting angiogenesis and vascular regression, and if Ang2 has the opposite effects; and (4) determine whether angiopoietins promote remodeling of lymphatic endothelial cells and fluid and cellular transport via airway lymphatics. Planned studies will use a combination of animal models of airway angiogenesis and inflammation in normal, transgenic, and knockout mice and in vitro studies of cultured endothelial cells to explore the cellular and molecular mechanisms of angiopoietin actions on blood vessels and lymphatic vessels. The approaches will take advantage of novel angiopoietin agonists and antagonists delivered as recombinant proteins or adenoviral vectors, state-of-the-art confocal microscopic imaging and quantification, and physiological and molecular methods. By elucidating the diverse actions of Ang1 and opposing or complementary actions of Ang2 that reduce plasma leakage, limit sprouting angiogenesis, and promote remodeling of airway blood vessels and lymphatic vessels, the planned studies will expand the perspective for developing future generations of therapies for asthma, chronic bronchitis, and other inflammatory airway diseases.