ION FLUXES IN ENDOTHELIAL CELL VOLUME REGULATION

本论文的主要目的是研究Na-K-Cl共输运 血管内皮细胞在内皮细胞中的作用 功能 已知内皮在维持中起核心作用 血管内环境稳定 在这方面，内皮细胞已经被证明是 参与调节血管过程如血栓形成， 血管收缩和平滑肌细胞增殖。 内皮 也提供了一个至关重要的选择性渗透屏障之间 血和氚 调节内皮屏障 对大分子如白蛋白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 空间. 因此，内皮细胞的功能重要性已经得到很好的认识。 记录在案。 然而，人们对离子的参与知之甚少。 内皮细胞功能中的转运蛋白。 以前的研究从 申请人的实验室已经确定内皮细胞表现出 一个重要的Na-K-Cl共转运系统，由多种 血管活性剂 这些结果表明，Na-K-Cl共转运可能 在正常内皮细胞功能中起重要作用。 两 生理作用已被证明为Na-K-Cl共转运在其他 细胞类型：非上皮细胞和上皮细胞的体积调节; 和离子穿过上皮的矢量运输。 作为一种初步方法， 来确定主要的钠钾氯离子的功能意义 共转运系统的内皮细胞，拟议的项目将 研究协同转运蛋白在内皮细胞体积中的作用 调控 细胞体积调节被假设为是关键的 用于维持内皮渗透屏障。 因此 内皮细胞体积对血管内皮细胞大分子通透性的影响 障碍也将被评估。 具体而言，本提案有两个 主要目的：1）验证Na-K-Cl共转运假说 参与内皮细胞体积调节;和2）测试 假设内皮细胞体积改变影响 内皮对大分子的通透性。 在这些研究中，Na-K-Cl 共转运活性和细胞内容积的各种培养 将评价内皮细胞。 大分子渗透性将是 使用两种系统评估白蛋白：1）体外系统， 在微孔膜细胞培养室上生长的内皮单层 插入物;和2）灌注的仓鼠肠系膜的体内系统 微血管 拟议的研究应提供以下方面的资料： 内皮细胞质膜离子转运系统作用 功能 这些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， 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.