Hypoxia-induced Endothelial Barrier Dysfunction

缺氧引起的内皮屏障功能障碍

• 批准号: 7822427
• 负责人: Usamah S Kayyali
• 金额: $ 6.52万
• 依托单位: TUFTS MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-06-01 至 2011-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7822427
• 关键词: Actins; Adherent Culture; Adhesions; Altitude; Biomechanics; Blood Vessels; Cardiac; Cells; Cytoskeleton; Development; Endothelial Cells; Endothelium; Event; Exposure to; Functional disorder; HSPB1 gene; Human; Hypoxia; Knock-out; Lead; Link; Liquid substance; Lung; MAPK14 gene; Mediating; Modeling; Mus; Myosin Light Chains; Pathway interactions; Permeability; Phosphorylation; Phosphotransferases; Physiological; Property; Pulmonary Edema; Pulmonary artery structure; Pulmonology; Rattus; Rho-associated kinase; Signal Pathway; Signal Transduction; in vivo; inhibitor/antagonist; insight; mitogen-activated protein kinase p38; monolayer; novel therapeutic intervention; programs; research study; response; rho

DESCRIPTION (provided by applicant): Non-cardiac pulmonary edema is a frequent affliction in pulmonary medicine and is caused by endothelial barrier dysfunction. It is now recognized that this dysfunction may be initiated by programmed cell signaling as opposed to non-specific disruption of the vascular barrier. Since the endothelial barrier is known to be altered by exposure to hypoxia leading to pulmonary edema, we have utilized a rat pulmonary artery microvascular endothelial cell (EC) monolayer culture model to study the effects of hypoxia on EC barrier function. Preliminary studies have led to the hypothesis that exposure to hypoxia initiates cell signaling through the p38 MAP kinase pathway involving MK2 and HSP27 activation that leads to actin cytoskeleton and hic-5 redistribution. These signaling events are associated with an alteration in biomechanical "tethering" and "stiffness" and enhanced permeability of the EC monolayer. "Tethering" may be regulated by the p38 MAP kinase pathway while "stiffness" is regulated by Rho/Rho kinase and myosin light chain phosphorylation. We plan in the present proposal to study these responses more thoroughly in the rat pulmonary artery microvascular EC monolayer and to perform confirmatory studies in similar cells from human pulmonary microvasculature. In addition, we will investigate these signaling pathways in mice in vivo using pharmacological inhibitors, as well as mice in which the expression of MK2, a key kinase in the p38 pathway, has been "knocked-out". Specifically, we plan to: Aim 1: Define signaling pathways important for mediating cytoskeletal changes in endothelial cell monolayers exposed to hypoxia; Aim 2: Determine the relevance of the biomechanical endpoints "stiffness" and "tethering", which increase with exposure to hypoxia, to physiological determinants of endothelial barrier function; and Aim 3: Evaluate the signaling events that lead to increased pulmonary endothelial permeability in hypoxia in vivo. The findings of this study are expected to further our understanding of mechanisms involved in the development of endothelial barrier dysfunction, in general, and to suggest targets for treatment of pulmonary edema.

描述（由申请人提供）：非心源性肺水肿是肺科常见病，由内皮屏障功能障碍引起。现在人们认识到，这种功能障碍可能是由程序性细胞信号传导引发的，而不是血管屏障的非特异性破坏。由于已知内皮屏障会因缺氧而改变，从而导致肺水肿，因此我们利用大鼠肺动脉微血管内皮细胞（EC）单层培养模型来研究缺氧对 EC 屏障功能的影响。初步研究得出这样的假设：缺氧会通过 p38 MAP 激酶途径启动细胞信号传导，涉及 MK2 和 HSP27 激活，从而导致肌动蛋白细胞骨架和 hic-5 重新分布。这些信号事件与生物力学“束缚”和“硬度”的改变以及 EC 单层的渗透性增强有关。 “束缚”可能受 p38 MAP 激酶途径调节，而“僵硬”则受 Rho/Rho 激酶和肌球蛋白轻链磷酸化调节。我们计划在本提案中更彻底地研究大鼠肺动脉微血管 EC 单层中的这些反应，并在来自人肺微血管系统的类似细胞中进行验证性研究。此外，我们将使用药物抑制剂在小鼠体内研究这些信号传导途径，以及p38途径中关键激酶MK2的表达已被“敲除”的小鼠。具体来说，我们计划： 目标 1：定义对于介导缺氧的内皮细胞单层细胞骨架变化很重要的信号通路；目标 2：确定生物力学终点“僵硬”和“束缚”与内皮屏障功能的生理决定因素的相关性，这些终点随着缺氧而增加。目标 3：评估导致体内缺氧情况下肺内皮通透性增加的信号事件。这项研究的结果有望进一步加深我们对内皮屏障功能障碍发展机制的理解，并提出肺水肿治疗的目标。