Endothelial cell potassium channels

项目摘要 血管内皮细胞调节动脉平滑肌细胞的收缩能力，从而调节局部器官血流和全身血压。内皮细胞控制收缩功能障碍是包括高血压在内的几种心血管疾病的特征，但涉及的病理机制尚不清楚。膜电位控制内皮细胞的功能，但涉及的离子通道和功能意义尚不清楚。瞬时受体电位(Trp)家族的几个成员在内皮细胞中表达，但生理功能尚不清楚。同样，一些受体配体和刺激物是内皮依赖的血管扩张剂，但其信号机制尚不清楚。我们的初步数据表明，在内皮细胞中，钾(K)通道被附近的瞬时受体电位(Trp)通道激活，导致血管扩张。数据还表明，高血压时K通道信号转导功能紊乱。对于这一建议，我们将研究K和Trp通道基因敲除小鼠。将调查三个具体目标。目的1验证内皮细胞钾电流调节动脉超极化和血管扩张的假说。目的2探讨色氨酸通道刺激内皮细胞钾通道，产生血管扩张的假说。目的3将研究一种假设，即全身性高血压与血管内皮细胞钾通道信号的病理性减弱有关，后者抑制这些蛋白的血管扩张。将使用的方法包括RT-PCR、Western blotting、生物素化、FRET、RNAi、co-IP、免疫荧光、膜片钳电生理、膜电位记录、细胞内钙成像、动脉肌图和血压遥测。这一建议将为血管内皮细胞钾通道的血管调节提供重要的新信息。

Project Summary Endothelial cells regulate arterial smooth muscle cell contractility, thereby modulating regional organ blood flow and systemic blood pressure. Dysfunctional endothelial cell control of contractility is a hallmark of several cardiovascular diseases, including hypertension, but pathological mechanisms involved are poorly understood. Membrane potential controls endothelial cell functions, but ion channels involved and functional significance are unclear. Several members of the transient receptor potential (TRP) family, are expressed in endothelial cells, but physiological functions are unclear. Similarly, several receptor ligands and stimuli are endothelium-dependent vasodilators, but their signaling mechanisms are poorly understood. Our preliminary data demonstrate that in endothelial cells, potassium (K+) channels are activated by nearby transient receptor potential (TRP) channels, leading to vasodilation. Data also suggest that K+ channel signaling is dysfunctional during hypertension. For this proposal, we will study K+ and TRP channel knockout mice. Three specific aims will be investigated. Aim 1 will test the hypothesis that K+ currents in endothelial cells regulate arterial hyperpolarization and vasodilation. Aim 2 will investigate the hypothesis that TRP channels stimulate K+ channels in endothelial cells, producing vasodilation. Aim 3 will study the hypothesis that systemic hypertension is associated with a pathological attenuation in K+ channel signaling in endothelial cells that inhibits vasodilation by these proteins. Methods used will include RT-PCR, Western blotting, biotinylation, FRET, RNAi, co-IP, immunofluorescence, patch-clamp electrophysiology, membrane potential recording, intracellular Ca2+ imaging, arterial myography and blood pressure telemetry. This proposal will provide significant novel information concerning vasoregulation by endothelial cell K+ channels.