HEMATOPOIETIC COMMITMENT OF HUMAN EMBRYONIC STEM CELLS

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 目的：促进人胚胎干细胞及其衍生物在血液病治疗中的临床应用。 了解造血干细胞发育的调控机制对于进一步提高造血干细胞在肿瘤学和基因治疗中的应用具有重要意义。该项目的总体目标是鉴定和鉴定人类最早的造血祖细胞，以体外hESC分化系统为模型确定导致造血干细胞发育的细胞和分子途径。 ES细胞的定向造血性分化再现了胚胎造血的许多方面，为研究人类造血发育的分子和细胞途径提供了独特的机会。在我们的实验室中，我们通过与OP9骨髓基质细胞共培养，建立了一套高效的HES细胞造血分化系统。使用这个系统，我们能够直接将HES细胞分化为所有主要血系(红系、髓系和淋巴系)的细胞，以及识别不同阶段的造血承诺。我们发现，人类最早的造血祖细胞(HPS)起源于CD34+群体，并最终可由白唾液(CD43)的表面表达来定义。此外，在CD43+人群中，我们发现Lin-CD34+CD43+CD45-造血祖细胞能够分化为包括淋巴样细胞在内的所有血系，这表明它们与造血干细胞的分化程度很近。然而，HES Lin-CD34+CD43+CD45-细胞的分子图谱显示，与造血干细胞自我更新和存活相关的基因表达发生了变化，反映了ES细胞来源的造血祖细胞的植入潜力有限。随着人们对HES细胞衍生物潜在治疗应用的兴趣与日俱增，识别对造血干细胞发育和多样化至关重要的基因尤为重要。所描述的实验系统为朝着这一方向发展奠定了坚实的平台。 本研究使用了WNPRC干细胞资源。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Objective: To advance human embryonic stem cells and their derivatives towards clinical application for treatment of blood disease. Understanding the mechanisms that regulate hematopoietic stem cell development is essential for further improvement of hematopoietic stem cell use in oncology and gene therapy. The overall goal of this project is to identify and characterize the earliest hematopoietic progenitors in humans to specify cellular and molecular pathways leading to hematopoietic stem cell development using in vitro hESC differentiation system as a model. Directed hematopoietic differentiation of ES cells reproduces many aspects of embryonic hematopoiesis, and provides a unique opportunity to study molecular and cellular pathways of hematopoietic development in humans. In our laboratory, we established a system for efficient hematopoietic differentiation of hES cells through coculture with OP9 bone marrow stromal cells. Using this system we were able to directly differentiate hES cells into cells of all major blood lineages (erythroid, myeloid and lymphoid), as well as identify different stages of hematopoietic commitment. We found that the earliest hematopoietic progenitors (HPs) in humans arise within CD34+ population and could be ultimately defined by surface expression of leukosialin (CD43). In addition, within CD43+ population, we identified lin-CD34+CD43+CD45- hematopoietic progenitors capable of differentiating toward all blood lineages including lymphoid cells, suggesting their hierarchical proximity to hematopoietic stem cells. However, molecular profiling of hES lin-CD34+CD43+CD45- cells revealed altered expression of genes associated with hematopoietic stem cell self-renewal and survival, reflecting limited engraftment potential of ES cell-derived hematopoietic progenitors. With increasing interest in potential therapeutic application of hES cell derivates, identification of genes essential for hematopoietic stem cell development and diversification is of particular importance. The described experimental system sets a solid platform to advance in this direction. This research used WNPRC Stem Cell Resources.