Isl1 and Wntbeta-catenin regulation of cardiac progenitor cells

心脏畸形是导致人类出生缺陷的主要原因，心脏病仍然是第一位 发达国家的成年人杀手最近，基于多能心脏祖细胞的疗法 （CPC）已成为有前途的潜在心脏治疗药物。它们可以从胚胎中纯化， 胚胎干细胞（ESC）系统并培养以分化成各种心脏细胞类型，包括 心肌细胞、平滑肌和内皮细胞。然而，产品总分类的基本机制 自我更新、增殖和分化是基于CPC的心脏治疗的先决条件， 正在浮现我已经证明了Wnt/p-Catenin信号是CPC扩增所必需和充分的 在初始规范发生后。我发现了CPC发展中的几个关键基因， 影响|3-连环蛋白，包括Isletl、Myocd和Smydl。值得注意的是，β-连环蛋白稳定显著地 下调Isletl，心脏发生的关键调节因子，短暂标记未分化的CPC。 相应地，Isletl缺失的胚胎具有增加的CPC数量，这表明Isletl可能是一种细胞因子。 CPC中Wnt/β-连环蛋白信号的重要介导物。通过使用小鼠遗传学和ESC系统， 发现Wnt/p-Catenin信号传导作为CPC的中央调节器，通过整合来自 Notchi和调节涉及Isll、Myocd和Smydl的下游转录事件的级联。 这些发现为探索Isletl的作用和调节途径奠定了基础， Wnt/p-Catenin信号在CPC维持和分化中的作用我提出三个具体目标。(1)到 确定Isletl是否影响CPC的自我更新、增殖和分化。(2)以确定是否 Isletl是Wnt/β-连环蛋白信号转导介导的CPC扩增的重要效应子。(3)以确定是否 P-连环蛋白和Isletl通过Notch信号传导调节以介导CPC扩增和分化。

Heart malformation is the leading cause of human birth defects and heart disease remains the number one killer of adults in the developed world. Recently, therapies based on multipotent cardiac progenitor cells (CPCs) have emerged as promising potential cardiac therapeutics. They can be purified from embryos or embryonic stem cell (ESC) systems and cultured to differentiate into various cardiac cell types including cardiomyocytes, smooth muscle and endothelial cells. However, the mechanisms underlying CPC self-renewal, proliferation and differentiation, a prerequisite for CPC-based cardiac therapy, are still emerging. I have demonstrated that Wnt/p-Catenin signaling is necessary and sufficient for CPC expansion after initial specification had occurred. I found several pivotal genes in CPC development that are negatively affected by |3-Catenin including Isletl, Myocd and Smydl. Notably, p-Catenin stabilization dramatically downregulated Isletl, a key regulatorof cardiogenesis that transiently marks undifferentiated CPCs. Correspondingly, Isletl-null embryos had an increased number of CPCs, suggesting that Isletl may be an important mediator of Wnt/p-Catenin signals in CPCs. Through use of mouse genetics and ESC systems, I found that Wnt/p-Catenin signaling functions as a central regulator of CPCs by integrating signals from Notchi and regulating a cascade of downstream transcriptional events involving Isll, Myocd and Smydl. These findings set the stage for an exploration ofthe role and the regulatory pathway of Isletl and Wnt/p-Catenin signaling in maintenance and differentiation of CPCs. I propose three specific aims. (1) To determine if Isletl affects the self-renewal, proliferation, and differentiation of CPCs. (2) To determine if Isletl is an essential effector for Wnt/p-Catenin signaling-mediated expansion of CPCs. (3) To determine if P-Catenin and Isletl are regulated by Notch signaling to mediate CPC expansion and differentiation.