HEMATOPOIETIC COMMITMENT OF HUMAN EMBRYONIC STEM CELLS

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目及 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 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。 了解调控造血干细胞发育的机制对于进一步改善造血干细胞在肿瘤学和基因治疗中的应用至关重要。本项目的总体目标是鉴定和表征人类最早的造血祖细胞，以体外hESC分化系统为模型，指定导致造血干细胞发育的细胞和分子途径。 胚胎干细胞定向造血分化可复制胚胎造血的许多方面，并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，我们建立了一个系统，通过与OP 9骨髓基质细胞共培养的hES细胞的高效造血分化。 使用该系统，我们能够直接将hES细胞分化为所有主要血液谱系（红系、髓系和淋巴系）的细胞，以及鉴定造血定型的不同阶段。我们发现，人类最早的造血祖细胞（HP）出现在CD 34+群体中，并最终通过表面表达的白唾液酸（CD 43）来定义。 此外，在CD43+群体中，我们鉴定了lin-CD34 + CD43 + CD45-造血祖细胞，其能够向包括淋巴样细胞在内的所有血液谱系分化，这表明它们与造血干细胞的层次接近。然而，hES lin-CD34 + CD43 + CD45-细胞的分子谱显示与造血干细胞自我更新和存活相关的基因表达改变，反映了ES细胞衍生的造血祖细胞有限的植入潜力。 随着对hES细胞衍生物的潜在治疗应用的兴趣增加，鉴定造血干细胞发育和多样化所必需的基因是特别重要的。所描述的实验系统设置了一个坚实的平台，在这个方向上前进。 这项研究使用了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.