Role of membrane potential in the regulation of endothelial cell deformability

越来越多的证据表明血管是醛固酮的靶点。最近的数据表明，在某些情况下，类固醇使内皮僵硬和脆弱。虽然临床相关性是明显的，并且醛固酮拮抗剂被成功地用于治疗，但醛固酮在内皮细胞中的作用机制尚不清楚。由各种离子通道的活动所支配的质膜电位差在调节内皮硬度和控制细胞的变形性中起关键作用。醛固酮导致内皮细胞顶膜上皮钠通道的表达，其被认为是去细胞化的。为了测试膜电位的作用和潜在的离子通道活动，我们设计了一个项目，操纵和测量内皮细胞的膜电位差应用荧光方法。同时，将量化细胞刚度和可变形性（通过使用原子力显微镜作为纳米传感器）。最后，一氧化氮的形成将与膜电位和细胞硬度有关。工作假设是内皮细胞膜电位差的大小决定了细胞的变形性，因此决定了NO的释放和血管平滑肌张力。通过使用阻断剂和激动剂，我们将在功能上确定不同的离子通道的内皮细胞膜电位差的重点是醛固酮调节的上皮钠通道。该项目的目的是确定导致细胞变形性变化的膜出生机制的关键参与者，并将其与内皮的生理功能联系起来。

There is accumulating evidence that blood vessels are targets for aldosterone. Recent data indicate that, under certain circumstances, the steroid renders endothelia stiff and vulnerable. Although the clinical relevance is obvious and aldosterone antagonists are successfully used for treatment, the mechanism of aldosterone action in endothelial cells is unknown. The electrical plasma membrane potential difference, dominated by the activities of various ion channels, could play a key role in the regulation of endothelial stiffness and in the control of the cell's deformability. Aldosterone leads to the expression of epithelial sodium channels in the apical membrane of endothelial cells which is supposed to depolarize the cells. To test the role of the membrane potential and the underlying ion channel activities we designed a project to manipulate and measure the membrane potential difference of endothelial cells applying fluorescence methods. In parallel, cell stiffness and deformability (by using the atomic force microscope as a nanosensor) will be quantified. Finally, nitric oxide formation will be related to membrane potential and cell stiffness. The working hypothesis is that the magnitude of the endothelial cell membrane potential difference determines the cell's deformability and, as a consequence, determines NO release and vascular smooth muscle tone. By using blockers and agonists we will functionally identify the different ion channels underlying the endothelial membrane potential difference with emphasis on aldosteroneregulated epithelial sodium channels. The aim of this project is to identify the key players of the membrane-born mechanisms that cause the changes in cellular deformability and to relate them to the physiological functions of the endothelium.