KCNE2在肺缺血再灌注损伤中对肺泡II型上皮细胞电压依赖性钾通道的调控作用及其机制的研究

Lung ischemia and reperfusion injury（LIRI）is the leading cause of postoperative complications and mortality after cardiopulmonary bypass (CPB), lung transportations and lung surgeries. The imbalance of Ionic current across Alveolar type II cells (ATII) membrane is the primary pathogenesis of LIRI. As the voltage-gated K channel (Kv) auxiliary β subunits, KCNE2 regulated Kv potassium channel function via interacting with Kv Alpha subunits. We found that KCNE2 expression decreased in the lung post LIRI. Meanwhile, KCNE2 deletion caused pulmonary edema and severe lung injury with inflammatory infiltration, indicating that KCNE2 plays a vital role in LIRI. Using KCNE2 knockout mice, the purpose of this study is to examine the effect of KCNE2 on ATII post Lung ischemia-reperfusion injury. The characteristics of Kv current in the ATII cell membrane will be studied with path clamping technique. Then, together with the use of immuno-fluorescence localization and immunoprecipitation technique, the detailed mechanisms of how KCNE2 interacts and modulates Kv alpha subunits will be studied. Understanding the functional role of KCNE2 on ATII membrane will facilitate the therapeutic development for prevention of pulmonary ischemia- reperfusion injury in clinical settings. The study has an important scientific significance and better clinic perspective. It is a very interesting and important work with novel creation.

肺缺血再灌注损伤（LIRI）是导致体外循环后及肺外科术后肺功能障碍及影响患者预后的最主要原因。肺泡II型上皮细胞（ATII）膜两侧离子流失衡是细胞缺血再灌注损伤的重要标志。KCNE2作为电压依赖性钾（Kv）通道的辅助β亚基，和α亚基共同调控钾通道功能。课题组在前期研究中发现缺血再灌注损伤肺组织中KCNE2表达减弱，其缺陷导致再灌注损伤后肺损伤进一步加重，提示KCNE2缺陷是LIRI的重要致病因素。本研究旨在通过KCNE2基因敲除小鼠，研究KCNE2对LIRI后ATII的影响；采用膜片钳技术，探索KCNE2对再灌注损伤小鼠ATII的Kv通道电流的影响；同时结合免疫荧光共定位，免疫共沉淀技术，研究KCNE2作用于ATII相关Kv通道α亚基的调节机制，从而明确KCNE2在LIRI中对ATII膜Kv通道的调控作用及机制，为临床肺缺血再灌注损伤的防治提供理论依据，是创新性强的原创性研究工作。

肺缺血再灌注损伤（LIRI）是导致体外循环后及肺外科术后肺功能障碍及影响患者预后的最主要原因。预实验中发现缺血再灌注损伤肺组织中KCNE2表达减弱，其缺陷导致再灌注损伤后肺损伤进一步加重，提示KCNE2缺陷是LIRI的重要致病因素。本研究结果证实小鼠敲除KCNE2基因后，肺部的电压依赖型钾离子通道a亚基KCNQ1和KCNB1基因表达减弱，但不影响其他KCNE家族成员基因的表达。KCNE2基因和KCNQ1基因在小鼠肺中共表达，提示肺部有KCNE2/KCNQ1通道复合体。KCNE2基因缺失使得动脉血液中氧浓度降低，二氧化碳浓度升高，肺泡细胞凋亡增加，同时增加血液和支气管肺泡灌洗液中炎性因子，肺部中性粒细胞的浸润。与肺渗出增加相一致的是，KCNE2基因敲除小鼠在基础状态下，肺组织的再灌注挽救激酶信号系统激活，但应对肺缺血再灌注损伤时，该系统激活不敏感，肺泡细胞损伤加重。该研究结果揭示了KCNE2基因参与肺正常生理功能的机制，及其应对肺部损伤时的发病机制。