ION FLUXES IN ENDOTHELIAL CELL VOLUME REGULATION

本提案的主要目的是研究钠-钾-氯共转运 血管内皮细胞在内皮细胞中的作用 功能。众所周知，血管内皮细胞在维持中起核心作用。 血管动态平衡。在这方面，内皮细胞已经被证明 参与调节血栓形成等血管过程， 血管收缩和平滑肌细胞增殖。内皮细胞 还提供了至关重要的选择性渗透性屏障 血液和间质。内皮细胞屏障的调节 对白蛋白等大分子的渗透性已被证明是一个主要的 血管与血管外液体分布的决定因素 空格。因此，内皮细胞的功能重要性已经得到了很好的认识。 有记录在案。然而，人们对ion的参与知之甚少。 内皮细胞中的转运蛋白功能。之前的研究来自 申请人的实验室已经证实内皮细胞表现出 突出的钠-钾-氯共转运系统，受多种 血管活性物质。这些发现表明，Na-K-Cl转运可能 在正常的内皮细胞功能中起着至关重要的作用。二 钠-钾-氯共转运的生理作用已被证明 细胞类型：非上皮性细胞和上皮性细胞的体积调节； 和跨上皮细胞的离子载体运输。作为最初的方法 确定突出的Na-K-Cl的功能意义 内皮细胞中的共运输系统，拟议的项目将 研究共转运体在内皮细胞体积中的作用 监管。细胞体积调节被认为是至关重要的 用于维持内皮细胞通透性屏障。因此， 内皮细胞体积对血管内皮细胞大分子通透性的影响 还将对障碍进行评估。具体地说，目前的提案有两个 主要目的：1)检验钠-钾-氯共转运的假说 参与内皮细胞体积调节；以及2)测试 内皮细胞体积改变影响内皮细胞数量的假说 内皮对大分子的渗透性。在这些研究中，Na-K-Cl 不同培养物共转运活性和胞内容量的研究 将对内皮细胞进行评估。大分子渗透性将是 使用两种系统评估白蛋白：1)体外白蛋白系统 微孔膜细胞培养箱内皮细胞单层生长 2)灌流的仓鼠肠系膜体内系统 微血管。拟议的研究应提供以下方面的信息 质膜离子转运系统在内皮细胞中的作用 功能。这一信息可能会导致新的治疗方法 治疗和预防血管病理生理状况，如 高血压和动脉粥样硬化。

The main goal of the present proposal is to investigate Na-K-Cl cotransport of vascular endothelial cells with respect to its role in endothelial cell function. The endothelium is known to play a central role in maintenance of vascular homeostasis. In this regard, endothelial cells have been shown to participate in regulating vascular processes such as thrombosis, vasoconstriction, and smooth muscle cell proliferation. The endothelium also provides a vitally important selective permeability barrier between the blood and interstitium. Modulation of the endothelial barrier permeability to macromolecules such as albumin has been shown to be a major determinant of fluid distribution between vascular and extravascular spaces. Thus, the functional importance of the endothelium has been well documented. However, little is known about the involvement of ion transporters in endothelial cell function. Previous studies from the applicant's laboratory have established that endothelial cells exhibit a prominent Na-K-Cl cotransport system that is regulated by a variety of vasoactive agents. These findings suggest that Na-K-Cl contransport may play an essential role in normal endothelial cell function. Two physiological roles have been demonstrated for Na-K-Cl cotransport in other cell types: volume regulation in both nonepithelial and epithelial cells; and vectorial transport of ions across epithelia. As an initial approach to determining the functional significance of the prominent Na-K-Cl cotransport system in endothelial cells, the proposed project will investigate the involvement of the cotransporter in endothelial cell volume regulation. Cell volume regulation has been hypothesized to be critical for maintenance of the endothelial permeability barrier. Thus, the influence of endothelial cell volume on macromolecular permeability of the barrier will also be evaluated. Specifically, the present proposal has two primary aims: 1) to test the hypothesis that Na-K-Cl cotransport participates in endothelial cell volume regulation; and 2) to test the hypothesis that alteration of endothelial cell volume influences endothelial permeability to macromolecules. In these studies, Na-K-Cl cotransport activity and intracellular volume of a variety of cultured endothelial cells will be evaluated. Macromolecular permeability will be assessed for albumin using two systems: 1) an in vitro system of endothelial monolayers grown on microporous membrane cell culture chamber inserts; and 2) an in vivo system of perfused hamster mesentery microvessels. The proposed studies should provide information regarding the role of plasma membrane ion transport systems in endothelial cell function. This information could lead to new therapeutic approaches to the treatment and prevention of vascular pathophysiological conditions such as hypertension and atherosclerosis.