In Vivo Potential of Human ES Cell-Derived Blood Cells

描述(由申请人提供)： 人类胚胎干细胞的分离和鉴定为实现再生医学的目标提供了一条令人兴奋的新途径。ES细胞在培养中几乎可以无限期地保持为未分化的细胞，但仍能在体内保留分化形成任何细胞类型的能力。因此，人类胚胎干细胞将提供一个很好的细胞来源，以取代受损或退化的细胞和组织来治疗一系列疾病。在血液学领域，从人ES细胞中获得的造血干细胞可用于白血病或骨髓瘤等恶性血液病患者的造血细胞移植治疗。成熟血细胞的生产可以提供无限供应的红细胞、血小板和其他血液产品，这些产品来自这种明确的来源，没有病毒或其他污染。人类胚胎干细胞的体外研究已经产生了造血细胞、神经细胞、心肌细胞和其他类型的细胞。人ES细胞与照射后的骨髓基质细胞共培养可产生髓系(白细胞)、红系(红细胞)和巨核系(血小板前体)的造血细胞。为了充分发挥它们的潜力，现在证明人类ES细胞来源的细胞在体内的功能是至关重要的。本研究旨在通过将未分化的人ES细胞和体外诱导为造血祖细胞的人ES细胞移植到免疫缺陷(NOD/SCID)小鼠体内，以确定来源于人ES细胞的造血细胞在体内的潜能。使用这种异种移植模型来证明人类SCID-再填充细胞(SRCs)是一种具有长期再生潜力的造血干细胞的有效措施。来自人类ES细胞的转基因(GFP标记)造血细胞也将被用来证明外源基因表达的稳定性，以及该模型作为基因替代治疗载体的潜在用途。将进行一系列移植到第二和第三宿主的实验，以证明人类ES细胞来源的HSCs能够维持长期自我更新的能力。由于恒河猴ES细胞也是可用的，这项建议的目标的成功完成将导致ES细胞来源的造血细胞移植的非人类灵长类动物模型。最终，将人类ES细胞定义为造血细胞移植治疗的新细胞来源的临床试验将为治疗恶性血液病、免疫缺陷、自身免疫和许多其他疾病开辟新的途径。

DESCRIPTION (provided by applicant): The isolation and characterization of human embryonic stem (ES) cells permits an exciting new approach to reach the goals of regenerative medicine. ES cells can be maintained virtually indefinitely as undifferentiated cells in culture, yet retain the ability to differentiate to form any cell type in the body. Therefore, human ES cells will provide an excellent source of cells to replace damaged or degenerated cells and tissues to treat a host of diseases. In the area of hematology, derivation of hematopoietic stem cells (HSCs) from human ES cells may be used for hematopoietic cell transplantation therapies for patients with hematologic malignancies such as leukemia or myeloma. Production of mature blood cells may provide an unlimited supply of red blood cells, platelets and other blood products from this well-defined source that is free of viral or other contaminants. Already, in vitro studies with human ES cells have produced hematopoietic, neural, cardiomyocyte, and other cell types. Hematopoietic cells of myeloid (white blood cells), erythroid (red blood cells), and megakaryocyte (platelet precursors) lineages can all be produced by co-culture of human ES cells with irradiated bone marrow stromal cells. To reach their full potential, it is crucial to now demonstrate in vivo function of human ES cell-derived cells. This proposal aims to define the in vivo potential of hematopoietic cells derived from human ES cells by transplantation of undifferentiated human ES cells, and human ES cells induced to form hematopoietic precursors in vitro, into immunodeficient (NOD/SCID) mice. Use of this xenotransplant model to demonstrate human SCID-repopulating cells (SRCs) is an effective measure of hematopoietic stem cells with long-term regenerative potential. Genetically modified (GFP-labeled) hematopoietic cells derived from human ES cells will also be used to demonstrate the stability of foreign gene expression, and the potential use of this model as a vector for gene replacement therapies. Serial transplantation experiments into secondary and tertiary hosts will be done to demonstrate the ability of HSCs derived from human ES cells to sustain long-term self-renewal. Since rhesus monkey ES cell are also available, successful completion of the aims of this proposal will lead to a non-human primate model of ES cell-derived hematopoietic cell transplantation. Eventually, clinical trials to define human ES cells as a novel source of cells for hematopoietic cell transplantation therapies will open new avenues to treat hematopoletic malignancies, immunodeficiencies, autoimmunity, and many other diseases.