Excitability Between Cardiac and Non-Cardiac Cells

描述（由申请人提供）： 将非心脏来源的细胞移植到心肌中是一种有吸引力的恢复丧失的心脏功能的方法，然而，移植细胞的电功能仍然知之甚少。 移植的细胞不太可能像天然心肌细胞那样在心脏合胞体中进行电通信。 事实上，心脏和非心脏细胞之间的交流可能是促细胞增殖的，正如初步报告所建议的那样。 因此，确定移植的非心脏细胞和宿主心肌细胞之间安全有效的电通信的要求至关重要。 心脏兴奋性由膜离子通道活性和经由心脏间隙连接的细胞与细胞偶联决定。 我们的初步研究表明，原代心肌细胞可以耦合和电通信与胚胎干细胞衍生的心肌细胞，但目前尚不清楚，这种通信是足够的功能内的心脏synctium。 我们的计算机模拟表明，减少缝隙连接耦合可导致持续性室性心律失常。 我们正在开发一种体外实验系统，其中标记的原代心室心肌细胞与胚胎干细胞衍生的心肌细胞和骨骼肌细胞共培养。 我们进行双细胞膜片钳来量化细胞对之间的电通信，并使用这些数据与计算机模型来确定移植细胞区域的促凋亡潜力。 由于我们的初步数据表明，有限的间隙连接偶联可能是致突变的，我们将实验性地过表达偶联蛋白，并重复评估偶联电导和致突变性。 这些研究旨在建立原代心室肌细胞和细胞移植候选细胞之间的电通讯机制。 该结果将提供对移植到心室肌中的细胞的电影响的深入了解，并导致一种治疗方法，以减少其致瘤行为。

DESCRIPTION (provided by applicant): Cell transplantation of non-cardiac origin cells into myocardium is an attractive approach for restoring lost cardiac function, however, the electrical function of transplanted cells remains poorly understood. The transplanted cells are unlikely to communicate electrically as native cardiomyocytes do within the cardiac syncytium. In fact, the communication between cardiac and non-cardiac cells may be pro-arrhythmic, as preliminary reports have suggested. Thus, it is crucial to define the requirements for safe and effective electrical communication between transplanted non-cardiac cells and host cardiomyocytes. Cardiac excitability is determined by membrane ion channel activity and cell-to-cell coupling via cardiac gap junctions. Our preliminary studies indicate that primary cardiac cells can couple and electrically communicate with embryonic stem cell derived cardiomyocytes, but it is not clear that this communication is sufficient to be functional within a cardiac synctium. Our computer simulations have demonstrated that decreased gap junction coupling can lead to sustained ventricular arrhythmias. We are developing an in vitro experimental system in which labeled primary ventricular cardiomyocytes are co-cultured with embryonic stem cell derived cardiomyocytes and skeletal myocytes. We perform dual cell patch clamping to quantify the electrical communication between cell pairs and use these data with computer models to determine arrhythmogenic potential of regions of transplanted cells. As our preliminary data indicate that limited gap junction coupling can be arrhythmogenic, we will experimentally overexpress coupling protein and repeat assessment of coupling conductance and arrhythmogenesis. The proposed studies seek to establish the mechanisms of electrical communication between primary ventricular myocytes and putative candidates for cellular transplantation. The results will provide insight into the electrical impact of cells transplanted into ventricular myocardium, and lead to a therapeutic approach to decrease their arrhythmogenic behavior.