Lu Yen-Yu, Chen Yao-Chang, Kao Yu-Hsun, Lin Yung-Kuo, Yeh Yung-Hsin, Chen Shih-Ann, Chen Yi-Jen
Division of Cardiology, Sijhih Cathay General Hospital, New Taipei City, Taiwan.
School of Medicine, Fu-Jen Catholic University, New Taipei City, Taiwan.
J Cell Mol Med. 2016 Jun;20(6):1182-90. doi: 10.1111/jcmm.12818. Epub 2016 Feb 29.
Colchicine is a microtubule disruptor that reduces the occurrence of atrial fibrillation (AF) after an operation or ablation. However, knowledge of the effects of colchicine on atrial myocytes is limited. The aim of this study was to determine if colchicine can regulate calcium (Ca(2+) ) homeostasis and attenuate the electrical effects of the extracellular matrix on atrial myocytes. Whole-cell clamp, confocal microscopy with fluorescence, and western blotting were used to evaluate the action potential and ionic currents of HL-1 cells treated with and without (control) colchicine (3 nM) for 24 hrs. Compared with control cells, colchicine-treated HL-1 cells had a longer action potential duration with smaller intracellular Ca(2+) transients and sarcoplasmic reticulum (SR) Ca(2+) content by 10% and 47%, respectively. Colchicine-treated HL-1 cells showed a smaller L-type Ca(2+) current, reverse mode sodium-calcium exchanger (NCX) current and transient outward potassium current than control cells, but had a similar ultra-rapid activating outward potassium current and apamin-sensitive small-conductance Ca(2+) -activated potassium current compared with control cells. Colchicine-treated HL-1 cells expressed less SERCA2a, total, Thr17-phosphorylated phospholamban, Cav1.2, CaMKII, NCX, Kv1.4 and Kv1.5, but they expressed similar levels of the ryanodine receptor, Ser16-phosphorylated phospholamban and Kv4.2. Colchicine attenuated the shortening of the collagen-induced action potential duration in HL-1 cells. These findings suggest that colchicine modulates the atrial electrical activity and Ca(2+) regulation and attenuates the electrical effects of collagen, which may contribute to its anti-AF activity.
秋水仙碱是一种微管破坏剂，可减少手术后或消融术后房颤（AF）的发生。然而，秋水仙碱对心房肌细胞作用的相关知识有限。本研究的目的是确定秋水仙碱是否能调节钙（Ca(2+)）稳态，并减弱细胞外基质对心房肌细胞的电效应。采用全细胞膜片钳、荧光共聚焦显微镜和蛋白质免疫印迹法，评估用（3 nM）或不用秋水仙碱处理24小时的HL-1细胞的动作电位和离子电流。与对照细胞相比，经秋水仙碱处理的HL-1细胞动作电位时程延长，细胞内Ca(2+)瞬变和肌浆网（SR）Ca(2+)含量分别减少10%和47%。与对照细胞相比，经秋水仙碱处理的HL-1细胞L型Ca(2+)电流、反向模式钠钙交换体（NCX）电流和瞬时外向钾电流较小，但超快速激活外向钾电流和阿朴吗啡敏感的小电导Ca(2+)激活钾电流与对照细胞相似。经秋水仙碱处理的HL-1细胞中SERCA2a、总受磷蛋白、苏氨酸17磷酸化受磷蛋白、Cav1.2、CaMKII、NCX、Kv1.4和Kv1.5的表达较少，但雷诺丁受体、丝氨酸16磷酸化受磷蛋白和Kv4.2的表达水平与对照细胞相似。秋水仙碱减弱了胶原蛋白诱导的HL-1细胞动作电位时程的缩短。这些发现表明，秋水仙碱可调节心房电活动和Ca(2+)调节，并减弱胶原蛋白的电效应，这可能有助于其抗房颤活性。
