Expansion of cardiac and hematopoietic progenitors by Wnt and Notch

描述(由申请人提供)： 为了实现再生医学在心肌发生领域的前景，有必要对心脏前体细胞的扩增、分化和维持进行有效的操作。无论翻译研究人员是试图通过在体内招募祖细胞来增强内源性再生能力，还是为了随后的交付或组织工程化生物假体的生成而在体外产生和扩增祖细胞，这都是必需的。造血领域的类似进展强调了详细了解对祖细胞扩增和适当分化至关重要的信号通路的重要性，在造血领域，调节干细胞扩张的GM-CSF、G-CSF和相关生长因子的临床应用提供了巨大的临床影响。在心血管领域，特异性调控祖细胞存活、扩增和分化的能力普遍缺乏。此外，可用于体外扩增的祖细胞来源仍然难以捉摸。为了克服这一局限性，许多研究集中在胚胎干细胞和非心脏成纤维细胞诱导的多潜能干细胞的生成和鉴定上，以最终用于组织工程治疗。这些研究表明，心肌细胞可以从这种细胞类型产生，但也揭示了由此产生的心肌细胞并不表现出成人心肌细胞的所有必要特征。因此，从ES或IPS细胞扩增和可控分化心肌细胞的能力在其用途上是有限的，部分原因是缺乏对心脏前体细胞在体内如何扩张和分化的了解。宾夕法尼亚州立大学/威斯康星州大学联合会应用的基本论点是，进一步阐明在胚胎中调节心脏和造血祖细胞发育的信号为识别有助于体外扩增和分化祖细胞的因素提供了一种合理的方法。因此，我们的合作项目结合了对发育过程中两个最重要的干细胞信号通路Wnt和Notch的分析，以及对来自多潜能干细胞(包括ES和iPS细胞)的心脏和血祖细胞的分析。然而，这一分析仍未得到发展，Wnt和Notch在发育中的心脏中的相互作用仍未被探索，尽管这些途径已知在许多其他干细胞群体中相互作用。这些研究将与关于Wnt和Notch在造血干细胞(HSCs)扩增和适当分化中的作用的协作链接申请中描述的那些研究相结合。宾夕法尼亚大学心脏部分的目标将集中在1)Wnt和Notch如何在发育过程中和ES/iPS细胞中促进心脏前体细胞的扩张和分化，以及2)确定Wnt和Notch操纵的心肌细胞和成熟的成年心肌细胞之间的异同。因此，宾夕法尼亚州立大学/密歇根州立大学祖细胞联盟建议表征Wnt和Notch信号在体内和体外扩增祖细胞的能力。

DESCRIPTION (provided by applicant): To fulfill the promise of regenerative medicine in the cardiac myogenesis field, it will be necessary to effectively manipulate expansion, differentiation, and maintenance of cardiac progenitor cells. This will be required regardless of whether translational researchers attempt to augment endogenous regenerative capacity via recruitment of progenitor cells in vivo, or whether progenitors are generated and expanded ex vivo for subsequent delivery or for the generation of tissue engineered bioprostheses. The importance of a detailed understanding of the signaling pathways important for progenitor expansion and proper differentiation is emphasized by analogous advances in the hematopoietic field, where the clinical use of GM-CSF, G-CSF and related growth factors, which regulate stem cell expansion has provided dramatic clinical impact. In the cardiovascular field, the ability to specifically regulate progenitor cell survival, expansion and differentiation is generally lacking. Moreover, a usable source of progenitors for ex vivo expansion remains elusive. To overcome this limitation, many studies have focused on the generation and characterization of cardiac progenitors from embryonic stem cells as well as induced pluripotential stem cells derived from non-cardiac fibroblasts for eventual use in tissue engineering therapies. These studies have shown that cardiac myocytes can be generated from such cell types but have also revealed that the resulting myocytes do not exhibit all of the necessary characteristics of adult cardiac myocytes. The ability to expand and controllably differentiate cardiac myocytes from ES or IPS cells is therefore limited in its uses, in part due to the lack of understanding of how cardiac progenitors expand and differentiate in vivo. The underlying thesis of the Penn/UW Consortium application is that further elucidation of the signals that mediate cardiac and hematopoietic progenitor development in the embryo provides a logical approach for the identification of factors useful for expansion and differentiation of progenitor cells ex vivo. Hence, our collaborative projects combine the analysis of two of the most vital stem cell signaling pathways, Wnt and Notch, during development and in cardiac and blood progenitors derived from pluripotential stem cells including ES and iPS cells. Nevertheless, this analysis remains undeveloped and the interactions of Wnt and Notch in the developing heart remain unexplored, although these pathways are known to interact in many other stem cell populations. These studies will interface with those described in the collaborative linked application on the role of Wnt and Notch in expansion and proper differentiation of hematopoietic stem cells (HSCs). The Aims of the UPenn cardiac portion will focus on 1) how Wnt and Notch promote cardiac progenitor expansion and differentiation in development and in ES/iPS cells and 2) defining the similarities and differences between Wnt and Notch manipulated cardiac myocytes and mature adult myocytes. Thus, the Penn/UW Progenitor Consortium proposes to characterize the ability of Wnt and Notch signaling to expand progenitors in vivo as well as ex vivo.