Calcium dynamics in embryonic-stem-cell derived cardiac myocytes.

用体外培养的小鼠胚胎干细胞分化心肌细胞。培养的细胞表现出自发跳动。与成体起搏器细胞一样，胚胎干细胞衍生细胞也表现出波状自发钙振荡，通过钠钙交换携带全细胞动作电位。在窦房结细胞中，这些振荡是由细胞内环AMP的升高所促进的。这表明，经过工程改造，具有高cAMP水平的细胞可以形成强健的起搏器。我们现在正着手研究从心室细胞中创造钙和膜耦合时钟的替代方法，使天然的窦房结细胞具有强健的跳动。除了转染产生所需信号环境的单个蛋白质外，我们还将探索-在衰老组织中-通过转染发育转录因子来重现导致SAN表型的发育程序。

Cardiac myocytes were differentiated in vitro from cultured embryonic stem cells derived from mice. The cultured cells displayed spontaneous beating. Like adult pacemaker cells, the embryonic stem cell derived cells were found to display wave-like spontaneous calcium oscillations which entrain with whole-cell action potentials by means of sodium-calcium exchange. As in sino-atrial node cells, these oscillations were promoted by elevation of intracellular cyclic AMP. This suggests that cells engineered to have constitutively high cAMP levels could form robust pacemakers. We are now embarking on studies of alternative means of creating, from ventricular cells, the coupled calcium and membrane clocks that endow natural sino-atrial node cells with robust beating. In addition to transfection with individual proteins that create the required signalling milieu, we will explore -- in aged tissue - the recapitulation of developmental programs that lead to the SAN phenotype by means of transfection of developmental transcription factors.