Hematopoietic precursor development from human ES cells

描述（由申请人提供）：造血已在许多动物模型中进行了广泛研究，包括小鼠胚胎干（ES）细胞和小鼠胚胎。然而，人造血发育的分析通常利用从骨髓或脐带血分离的血细胞。虽然这些出生后的人类造血干细胞（HSC）已经得到了很好的表征，但关于这些HSC如何在人类发育的初始阶段从早期前体细胞中产生的知之甚少。人类胚胎干细胞提供了一个最佳的起点，研究人类发育生物学的基本问题，并确定罕见的前体细胞的表型和遗传调控。该提案的总体目标是使用人ES细胞系统地表征人造血前体细胞发育。我们先前已经证明了从人ES细胞获得CD34+、CD45+和成熟骨髓系细胞的方法。最近，我们还从CD34+人ES细胞衍生的前体细胞衍生淋巴细胞。虽然我们证明了来自人ES细胞的造血细胞的有序发育，但仍然缺乏对人ES细胞造血所需条件的更完整理解。为了更好地表征早期人类造血的基本细胞和分子机制，我们将做以下工作。1)定义可溶性和细胞结合蛋白质，这些蛋白质对于从人ES细胞发育成血细胞至关重要，特别强调Wnt蛋白质。2)通过体外替代试验和移植到免疫缺陷小鼠中来表征人ES细胞衍生的HSC的表型。3)分离作为血液和内皮细胞谱系共同前体的成血管细胞或生血内皮细胞的克隆群体。这些目标的成功完成将大大提高我们利用人类胚胎干细胞来了解基本人类发育的能力，并在更好的干细胞治疗中发挥重要作用。（这些研究将使用NIH登记的WA01和WA09人类ES细胞）。与公共卫生的相关性：这些研究将对快速发展的再生医学领域产生重要影响。更好地理解从人ES细胞造血发育将转化为用于治疗各种恶性和非恶性血细胞疾病的造血细胞移植的新的细胞来源。这些细胞也可用作输血药物的新来源。

DESCRIPTION (provided by applicant): Hematopoiesis has been extensively studied in many animal models, including mouse embryonic stem (ES) cells and murine embryos. However, analyses of human hematopoietic development typically utilize blood cells isolated from bone marrow or umbilical cord blood. While these post-natal human hematopoietic stem cells (HSCs) have been well characterized, considerably less is known about how these HSCs arise from earlier precursor cells during the initial stages of human development. Human ES cells provide an optimal starting point to study fundamental questions of human developmental biology, and to define phenotypic and genetic regulation of rare precursor cells. The overall goal of this proposal is to use human ES cells to systematically characterize human hematopoietic precursor cell development. We have previously demonstrated methods to derive CD34+, CD45+ and mature myeloid-lineage cells from human ES cells. More recently, we have also derived lymphocytes from CD34+ human ES cell-derived precursor cells. While we demonstrate an ordered development of hematopoietic cells derived from human ES cells, more complete understanding of the conditions required for hematopoiesis from human ES cells is still lacking. To better characterize fundamental cellular and molecular mechanisms of early human hematopoiesis, we will do the following. 1) Define soluble and cell bound proteins essential for development of blood cells from human ES cells, with particular emphasis on Wnt proteins. 2) Characterize the phenotype of human ES cell derived HSCs by in vitro surrogate assays and transplantation into immunodeficient mice. 3) Isolate clonal populations of hemangioblast or hemogenic endothelial cells that serve as a common precursor to both blood and endothelial cell lineages. Successful completion of these aims will significantly advance our ability to use human ES cells to understand basic human development, with important applications to better stem-cell based therapies. (These studies will use NIH registry WA01 and WA09 human ES cells). Relevance to public health: These studies will have important impact in the rapidly growing area of regenerative medicine. Better understanding of hematopoietic development from human ES cells will translate to novel source of cells for hematopoietic cell transplants used to treat a variety of malignant and non-malignant blood cell diseases. These cells may also be used as a new source for transfusion medicine.