Kir2.1内向整流钾电流主导的和HCN电流的精确平衡在自律细胞起搏中的作用研究

心脏窦房结及传导系统控制着心脏正常收缩的频率和节律，由窦房结和/或传导系统功能障碍引起的严重缓慢型心律失常，是40岁以上人群常见的心脏疾病之一，目前仍然以植入电子起搏器治疗为主。然而，心脏自律细胞起搏的确切机制迄今仍不是十分清楚。我们前期的实验证明，具有完全内向整流性的IK1和HCN2电流精确平衡能促进自发动作电位的产生，为研究起搏机制提供了新的思路。因此，我们推测：Kir2.1电流主导的和HCN电流的精确平衡可能是自律细胞起搏的新机制。为了验证这一假说，本项目拟采用具有自律性的iPSC-心肌细胞、乳鼠心肌细胞以及转基因小鼠心脏的窦房结和蒲肯野细胞，利用分子生物学，病毒转染，定点突变，膜片钳等方法，从分子，细胞以及整体水平来剖析Kir2.1电流主导的和HCN电流的精确平衡在起搏中的作用。本研究有望阐明心脏自律细胞起搏的机制，为心动过缓的防治策略和药物靶点提供新的线索和理论依据。

The rate and rhythm of cardiac contration are controlled by cardiac sinoatrial node and conduction system. Dysfunction of sinoatrial node and/or conduction system could induce slow arrhythmia, which is one of the most common cardiac diseases in people over 40 years old, is mainly treated by implantation of an electronic pacemaker at present. However, the mechanism of cardiac pacemaker activity is still not very clear. Our previous results showed that precise balance between complete inwardly rectified IK1 and HCN2 currents can induce the initiation of spontaneous action potentials, providing a new idea in studying the mechanism of pacemaker activity. We propose that Kir2.1-controlled precise balance with HCN current may be the new mechanism of cardiac pacemaker cells. In order to testify the hypothesis, we plan to employ pacing iPSC-CMs, rat neonatal cardiomyocytes (RNCMs), cardiac sinoatrial node cells and purkinje cells of gene knock-in mice to explore the role of precise balance between Kir2.1 and HCN currents in cardiac pacemaker activity and the key role of Kir2.1 current in the balance from levels of molecules, cells and in vivo by using patch clamp, virus transfection, site-directed mutagenesis and molecular biology. The present study will uncover a new underlying mechanism of pacemaker activity and it will be a therapeutic target for slow arrhythmia caused by dysfunction of sinoatrial node and/or conduction system.