Subtype Spec.& Arrhythmogenica Potential of Stem Cell Derived Cardiomyocytes

项目2：干细胞衍生心肌细胞的亚型规格和致心律失常潜力。 来源于人胚胎干细胞（hESC）的心肌细胞在心脏移植方面具有巨大的前景。 修复，既用于替换梗死后的心室心肌，也可作为“生物起搏器”， 病窦综合征之类的疾病我们已经报道了产生大量高浓度的 从hESC纯化的心肌细胞，但这些制备物包括具有不同的结/起搏点的细胞 和“工作”（即室样）表型。为了使这些细胞既有用又安全，它们必须 与每个应用程序相匹配的电生理特性。因此，本项目将制定办法， 控制hESC衍生物的心脏亚型，然后将决定它们的电生理行为 移植到完整的和梗死的心脏后。在目标1中，我们将开发一个遗传选择系统 以遵循源自hESC的心脏亚型的谱系关系。这项工作建立在我们的 初步发现，来自cGATA 6基因的启动子元件鉴定了hESC衍生的 具有结节表型的心肌细胞。在目标2中，我们将阐明分子事件， neuregulin/ErbB信号传导调节hESC衍生的心肌细胞的心脏亚型。这项工作将采用目标1的遗传报告，但也将导致补充药理学方法来控制心脏亚型规格。在目标3中，我们将解决两个不确定性的hESC衍生的心肌细胞移植后的电生理行为。首先，我们将测试这些细胞是否与正常和非正常情况下的宿主肌肉电耦合并同步跳动。 梗塞的心脏其次，我们将测试的假设，即他们的移植将调节梗死相关的心律失常的发病率，而移植物相关的心律失常的发病率可以通过控制输入细胞制剂的表型“调谐”。

Project 2: Subtype Specification and Arrhythmogenic Potential of Stem Cell Derived Cardiomyocytes. Cardiomyocytes derived from human embryonic stem cells (hESCs) have tremendous promise for cardiac repair, both for replacing ventricular myocardium after an infarct and serving as a "biologic pacemaker" in diseases like sick-sinus syndrome. We have reported methods to generate large quantities of highly purified cardiomyocytes from hESCs, but these preparations include cells with distinct nodal/pacemaker and "working" (i.e. chamber-like) phenotypes. For these cells to be useful and safe, they must have electrophysiological properties matched to each application. Hence, this project will develop approaches to control the cardiac subtype of hESC derivatives and then will determine their electrophysiological behavior following transplantation in intact and infarcted hearts. In Aim 1, we will develop a genetic selection system to follow the lineage relationships of cardiac subtypes derived from hESCs. This work builds on our preliminary findings that a promoter element from the cGATA6 gene identifies hESC-derived cardiomyocytes with the nodal phenotype. In Aim 2, we will elucidate the molecular events by which neuregulin/ErbB signaling regulates the cardiac subtype of hESC-derived cardion\yocytes. This work will employ the genetic reporters from Aim 1 but will also lead to complementary pharmacological approaches to control cardiac subtype specification. In Aim 3, we will address two uncertainties regarding the electrophysiological behavior of hESC-derived cardiomyocytes following transplantation. First, we will test whether these cells are electrically coupled and beat synchronously with host muscle in normal and infarcted hearts. Second, we will test the hypothesis that their transplantation will modulate the incidence of infarct-related arrhythmias, while the incidence of graft-associated arrhythmias can be "tuned" by controlling the phenotype of the input cell preparation.