Kv1.5钾通道在氧化应激介导的易卒中型肾性高血压脑血管内皮损伤过程中的作用研究

项目名称： Kv1.5钾通道在氧化应激介导的易卒中型肾性高血压脑血管内皮损伤过程中的作用研究

项目编号： No.30873059

项目类型： 面上项目

立项/批准年度： 2009

项目学科： 轻工业、手工业

项目作者： 王冠蕾

作者单位： 中山大学

项目金额： 32万元

中文摘要： 血管内皮氧化应激损伤是心血管疾病如动脉粥样硬化（AS）的中心环节，其信号通路尚未清楚。Kv1.5钾通道既是抗心房颤动的新药靶，又在肺动脉高压等疾病中通过参与氧化应激介导的血管平滑肌重构起重要作用，但尚不清楚Kv1.5是否参与血管内皮氧化应激损伤？如参与，其相关信号通路如何？本研究采用体外模拟AS血管内皮损伤的细胞模型，即OxLDL诱导人血管内皮细胞氧化应激损伤，应用siRNA干扰下调Kv1.5以及腺病毒载体感染过表达Kv1.5等方法，发现Kv1.5-ROS-线粒体信号通路参与OxLDL诱导内皮细胞氧化应激损伤，沉默或者过表达Kv1.5蛋白能抑制或者增强OxLDL诱导细胞ROS和线粒体ROS水平，通过影响线粒体功能，进而抑制或增强OxLDL诱导内皮细胞的凋亡。但在ApoE基因敲除AS小鼠模型上，未发现血管内皮Kv1.5蛋白随AS进程如预期有明显改变，这可能是在体调控因素复杂。应用过氧化氢诱导大鼠颈动脉内皮损伤在体模型，发现下调Kv1.5明显抑制过氧化氢引起的颈动脉内皮损伤。本研究提示Kv1.5可成为干预血管内皮氧化应激损伤的新靶点，但其在血管内皮氧化应激损伤相关疾病中的作用还有待确证。

中文关键词： Kv1.5钾通道; 血管内皮; 氧化应激; 线粒体; 凋亡

英文摘要： Kv1.5 is one member of voltage-dependent potassium channel family, has been assigned the important role in the cell apoptosis and oxidant stress signaling pathway in vascular smooth muscle cells. The oxidative endothelial injury is taken as an initial key event in the development of atherosclerosis and other cardiovascular diseases. However, the role of Kv1.5 in oxidative endothelial injury is unknown. Therefore, the present study was designed to examine whether Kv1.5 would affect oxidative stress-induced endothelial injury and the underlying molecular mechanism, as well as change in Kv1.5 expression in endothelium in animal disease models. Methods and Results: The Kv1.5 protein expression and the parallel measurements of cellular apoptosis, cellular and mitochondral ROS generation were detected in human pulmonary artery endothelial cells (HPAECs) stimulated with oxLDL or angiotensin II. The essential role for Kv1.5 in oxLDL-induced oxidative injury was revealed by siRNA silencing and adenovirus vector overexpressing technology. overexpression of Kv1.5 by adenovirus vector increased oxLDL–nduced cellular damage, intracellular or mitochondria-derived ROS. In contrast, the induction of oxidative cell damage and excess ROS generation were significantly attenuated by Kv1.5 siRNA interference or Kv1.5 inhibitor. The siRNA and adnoviral assays also showed that mitochondria uncoupling protein 2 (UCP2) was involved in the modulation of oxLDL-induced endothelial damage by Kv1.5. These data suggested Kv1.5-ROS-mitochondria pathway could be involved in oxLDL-induced endothelial injury. However, the immunochemistry analysis could not detect any significant change in Kv1.5 expression in aortic endothelium in ApoE deficient mouse atherosclerosis models, which maybe due to the influence from vascular smooth muscle, detecting tissue or other complex mechanism. We then transferred to an in vivo oxidative endothelial apoptosis model, evoking endothelial apoptosis by intracarotid arterial administration of 0.01 mmol/L hydrogen peroxide for 5 minutes, which may and found that Kv1.5 inhibitor DPO-1(3mg/kg,i.p) could significantly repress endothelial apoptosis induced by hydrogen peroxide, which was in line with our findings in in vitro cell models. Conclusion: The findings in the present study suggested that Kv1.5 may be invovled in oxLDL/angiotensin II-induced oxidative endothelial apoptosis via mitochondrial associated ROS generation mechanism. The interference of Kv1.5 may serve as a potential new target for prevention and treatment of oxidative-stress related endothelial injury during cardiovascular diseases.

英文关键词： Kv1.5; endothelial cells; oxidative stress; mitochondria; apoptosis