Stem Cell Differentiation for Myocardial Therapy

描述（由申请人提供）：受损心肌的细胞替代疗法一直是心力衰竭治疗中一个重要但难以实现的目标。我们实验室的总体目标是了解肌肉细胞增殖和分化的调节，以及这些过程如何介导心肌发育和疾病。我们目前的方法是鉴定和表征来自人类胚胎干细胞（hESCs）的心肌细胞，并利用这些细胞来模拟心肌发育和探索心肌疾病的细胞治疗。我们的目标是确定hesc衍生心肌细胞发育成不同心肌细胞类型的亚群，确定hesc衍生心肌细胞最有效植入宿主组织的发育阶段，并证明hesc衍生细胞可用于改善心肌损伤后的心功能。这些直接关系到PA-05-043的长期目标（心脏、肺、血液和衰老疾病的细胞基础治疗的定向干细胞分化）。该建议的具体目标是：1)鉴定增殖hESCs的特定亚群，这些亚群优先分化为心肌细胞；我们将通过将特定hESC亚群分化为体外心肌细胞，并表征发育和室特异性基因表达和动作电位传播来实现这一目标；2)确定hesc源性心肌细胞在体内最有效移植的发育阶段以及组织环境在心肌细胞亚特化中的作用；我们将通过开发报告hESC细胞系和“分子信标”策略来分离特定发育时间点的心肌细胞，并确定它们在小鼠心肌中的植入和分化来实现这一目标；3)用hesc来源的心肌细胞在小鼠心肌梗死模型中证明细胞治疗的效果；我们将通过评估hesc来源的心肌细胞移植后心肌梗死小鼠模型的心功能和电传导来实现这一目标。所提出的研究将为人类心肌发生提供新的见解，并为心肌再生提供新的途径。

DESCRIPTION (provided by applicant): Cell replacement therapy for damaged myocardium has been an important yet elusive goal in the treatment of heart failure. Our laboratory's overall goal is to understand the regulation of muscle cell proliferation and differentiation, and how such processes mediate myocardial development and disease. Our current approaches are to identify and characterize myocardial cells derived from human embryonic stem cells (hESCs), and to use these to both model myocardial development and explore cell therapies for myocardial diseases. Our goals for this proposal are to determine subpopulations of hESCs that develop into different cardiomyocyte types, identify the developmental stage at which hESC-derived myocardial cells most effectively engraft into host tissue, and demonstrate that hESC-derived cells can be used to improve cardiac function following myocardial injury. These relate directly to the long-range goal of PA-05-043 (Directed Stem Cell Differentiation for Cell-Based Therapies for Heart, Lung, And Blood, and Aging Diseases). The specific aims of this proposal are to: 1) identify specific subpopulations of proliferating hESCs that preferentially differentiate into cardiomyocytes; we will accomplish this by differentiating specific hESC subpopulations into cardiomyocytes in vitro, and characterizing developmental- and chamber-specific gene expression and action potential propagation; 2) determine the developmental stage at which hESC-derived myocardial cells most effectively engraft in vivo and the role of the tissue environment in cardiomyocyte subspecialization; we will accomplish this by developing reporter hESC lines and "molecular beacon" strategies for isolating myocardial cells at specific developmental time points, and determining their engraftment and differentiation in mouse myocardium in vivo; and 3) demonstrate the effects of cell therapy with hESC-derived myocardial cells in a mouse model of myocardial infarction; we will accomplish this by evaluating cardiac function and electrical conduction in a mouse model of myocardial infarction following transplant with hESC-derived myocardial cells. The proposed studies will provide new insight into human cardiac myogenesis, and offer novel approaches to myocardial regeneration.