Cardioprotective Repair through Cardiopoiesis

描述（由申请人提供）：心肌梗死是由于心肌自我更新能力有限而导致收缩功能丧失的主要发病原因。胚胎干细胞分化为心肌细胞的能力为再生修复提供了机会。事实上，这些典型干细胞的治疗用途的基础在于其固有的多能性，然而，多谱系分化的独特能力带来了肿瘤生长的危险，这超过了阻碍修复应用的益处。本建议的目的是磨练干细胞的可塑性，以消除恶性肿瘤倾向的非引导分化，以实现安全修复。初步研究表明，胚胎干细胞群体在发育中的胚胎样体中，在内胚层导向的心脏营养信号的短暂窗口期，具有最终的心脏生成能力，由此产生的中胚层特异性产生祖“心脏生成”干细胞表型。目标1将(i)利用基于胚胎体的干细胞分化分离这种促心源性群体，（ii）确定其分子特征，（iii）确定其最终致心转化的倾向。目标#2将(i)破译内胚层来源的心脏营养信号，（ii）以无胚胎体的方式大规模招募促心干细胞群体，以及（iii）在体内验证这种新型干细胞类型的安全性。Aim #3将(i)评估获得的心脏干细胞在治疗心肌梗死方面的治疗潜力，（ii）确定修复的潜在机制，以及（iii）工程干细胞增强对压力的耐受性，实现增强的心脏保护结果。基于心脏干细胞的特征和心脏营养线索的分析，本提案将剖析心脏生成的基本过程，以确保多能性的形成限制。分子和细胞水平的心肌发生解剖将进一步整合到治疗范式中，并转化为器官和生物体水平，用于心肌梗死的安全细胞再生治疗。

DESCRIPTION (provided by applicant): Myocardial infarction is a leading cause of morbidity with loss of contractile performance precipitated by the limited capacity of heart muscle for self-renewal. The aptitude of embryonic stem cells for differentiation into cardiomyocytes provides an opportunity for regenerative repair. Indeed, the basis for therapeutic use of these quintessential stem cells lies in their inherent pluripotency, yet the distinct ability for multi-lineage differentiation carries the liability of neoplastic growth that outweighs benefit impeding reparative applications. The objective of this proposal is to hone stem cell plasticity in order to nullify malignancy-prone unguided differentiation for safe repair. Preliminary studies demonstrate the aptitude for definitive cardiogenic commitment of an embryonic stem cell population within the developing embryoid body, during a transient window of endoderm-directed cardiotrophic signaling, with the resulting specification of the mesoderm yielding a progenitor "cardiopoietic" stem cell phenotype. Aim #1 will (i) isolate this pro-cardiogenic population utilizing embryoid body-based stem cell differentiation, (ii) define its molecular identity, and (iii) determine its propensity for terminal cardiomyogenic transformation. Aim #2 will (i) decipher the endoderm-derived cardiotrophic signaling, (ii) recruit in an embryoid body-free manner the pro-cardiogenic cardiopoietic population at large scale, and (iii) validate in vivo the safety profile of this novel stem cell type. Aim #3 will (i) assess the curative potential of procured cardiopoietic stem cells in treating myocardial infarction, (ii) determine the underlying mechanism for repair, and (iii) engineer stem cells for augmented tolerance to stress achieving enhanced cardioprotective outcome. Based on the characterization of cardiopoietic stem cells and the profiling of cardiotrophic cues, this proposal will dissect the fundamental process of cardiopoiesis securing formative confinement of pluripotency. Dissection of cardiogenesis at the molecular and cellular level will be further integrated into a therapeutic paradigm, and translated to the organ and organism level for safe cell-based regenerative therapy of myocardial infarction.