论文部分内容阅读
大电导的钙活化钾通道(large-conductance calcium-activated potassium channel,BKCa)和电压依赖性钾通道Kv1.5在气道高反应性的发生机制中具有重要作用。已知吸烟可致气道高反应,但钾通道的变化在其发病中的作用尚需进一步阐明。本文旨在研究香烟提取物(cigarette smoke extract,CSE)对培养的大鼠支气管平滑肌细胞(bronchial smooth muscle cells,BSMCs)钾通道BKCa和Kv1.5表达的直接作用,以及蛋白激酶C(protein kinase C,PKC)在其中的作用。实验采用原代培养大鼠BSMCs,用5%CSE刺激,免疫印迹检测PKC亚型的表达和转位,半定量RT-PCR、免疫印迹实验检测BKCa和Kv1.5的mRNA和蛋白表达,然后用PKC抑制剂BIM和G?e6983与CSE共作用,检测其对BKCa和Kv1.5的mRNA和蛋白表达的影响。结果显示,5%CSE使PKCε、η、θ发生明显的膜转位,并使BKCa和Kv1.5的蛋白和mRNA表达明显降低;选择性PKC抑制剂BIM或G?e6983与CSE共同作用,均可使BKCa和Kv1.5的蛋白和mRNA表达部分恢复。上述结果提示,CSE可引起BSMCs的BKCa和Kv1.5表达下调,PKCε、η、θ参与其信号转导。
Large conductance calcium-activated potassium channel (BKCa) and voltage-dependent potassium channel Kv1.5 play an important role in the pathogenesis of airway hyperresponsiveness. Smoking is known to cause airway hyperresponsiveness, but the role of potassium channel changes in its pathogenesis needs to be further elucidated. This study aimed to investigate the direct effects of cigarette smoke extract (CSE) on the expression of BKCa and Kv1.5 in potassium channel of cultured rat bronchial smooth muscle cells (BSMCs), and the effect of protein kinase C , PKC) in which the role. The primary cultured rat BSMCs were stimulated with 5% CSE, the expression and translocation of PKC isoforms were detected by Western blotting. The mRNA and protein expressions of BKCa and Kv1.5 were detected by semi-quantitative RT-PCR and Western blotting, respectively PKC inhibitor BIM and G? E6983 co-treated with CSE to detect their effects on mRNA and protein expression of BKCa and Kv1.5. The results showed that 5% CSE induced obvious membrane translocation of PKCε, η, θ, and significantly decreased the protein and mRNA expression of BKCa and Kv1.5. The selective PKC inhibitor BIM or G e6983 interacted with CSE BKCa and Kv1.5 protein and mRNA expression can be partially restored. The above results suggest that CSE can cause the down-regulation of BKCa and Kv1.5 expression in BSMCs, and PKCε, η, θ participate in their signal transduction.