Integration and Arrhythmia Suppression with hESC-Derived Cardiomyocyte Grafts

描述(申请人提供)：由于其巨大的体外扩增能力和分化为明确的心肌细胞的能力，多潜能的人胚胎干细胞(HESCs)是基于细胞的心脏治疗的一个有吸引力的来源。本课题组有令人振奋的新数据表明，人胚胎干细胞来源的心肌细胞(hESC-CMS)在豚鼠心脏移植后可以与宿主心肌偶联，但在损伤心脏中它们的整合还不完善。我们还发现，hESC-CM移植显著降低了自发性和诱发性心律失常的发生率。目前的应用建立在这些观察的基础上，并有两个总体目标：第一，确定这种心律失常抑制作用的机制基础；第二，测试进一步增强受损心脏中hESC-CMS的机电整合的新方法。在目标1中，我们将检验这样一个假设，即hESC-CM移植对电稳定性的有利影响与它们的功能整合有关。在目标2中，我们将在豚鼠脑梗塞模型中检验缝隙连接修饰剂治疗将改善hESC-CM移植后宿主-移植物偶联的假设。最后，在目标3中，我们将使用体外模型来开发Wnt5a介导的趋化作用，作为补充策略来提高hESC-CM移植物的整合。

DESCRIPTION (provided by applicant): Because of their tremendous capacity for in vitro expansion and ability to differentiate into phenotypically unambiguous cardiomyocytes, pluripotent human embryonic stem cells (hESCs) are an attractive source for cell-based cardiac therapies. Our group has exciting new data indicating that hESC-derived cardiomyocytes (hESC-CMs) can couple with host myocardium following transplantation in guinea pig hearts, but their integration is imperfect in injured hearts. We have also found that hESC-CM transplantation significantly decreases the incidence of both spontaneous and induced arrhythmias. The present application builds on these observations and has two overall goals: first, to determine the mechanistic basis for this arrhythmia-suppressive effect and, second, to test novel approaches to further enhance the electromechanical integration of hESC-CMs in injured hearts. In Aim 1, we will test the hypothesis that the beneficial effects of hESC-CM transplantation on electrical stability correlates with their functional incorporation. In Aim 2, w will test the hypothesis that treatment with gap-junction modifiers will improve host-graft coupling following hESC-CM transplantation in a guinea pig infarct model. Finally, in Aim 3, we will use in vitro models to develop Wnt5a-mediated chemotaxis as a complementary strategy to improve the integration of hESC-CM grafts.