Gene Transfer And Ex Vivo Manipulation Of Hematopoietic

临床和基础实验室研究旨在开发造血细胞（包括干细胞、祖细胞和淋巴细胞）的有效和安全的基因转导和离体操作策略，并使用遗传标记技术来回答有关体内造血的重要问题。在被证明是唯一预测人类临床结果的检测方法的恒河猴模型中，我们专注于优化向原始干细胞和祖细胞的基因转移，并使用遗传标记技术来了解干细胞在体内的行为。我们继续进一步提高基因转移到恒河猴移植细胞中的效率，导致早期标记细胞的水平高达50- 80%，在所有谱系中具有5-35%的稳定水平，这是具有临床实用性的范围。我们已经发现，主动循环转导的细胞具有植入缺陷，其可以通过在纤连蛋白片段上与单独的干细胞因子进行短培养来校正。高水平使我们能够在大型动物模型中首次继续跟踪克隆对造血的贡献。我们已经利用了一种新的技术，允许同时评估多个克隆的外周血群体的贡献。我们已经发现了一个不同的移植细胞群体，它们在移植后的前1-2个月起作用，然后被一组非常稳定的80多个克隆所取代，这些克隆对所有谱系的贡献超过3年。我们已经研究了细胞因子治疗，放疗和化疗对干细胞克隆体内行为的影响，使用这种强大的方法。到目前为止，我们已经表明，用G-CSF或SCF延长细胞因子治疗不会显著改变有助于造血的干细胞克隆的数量，也不会导致可检测的克隆耗尽或招募。相比之下，低剂量全身照射的治疗导致有助于外周血谱系的干细胞克隆的显著减少。白消安的研究正在进行中。我们还开始仔细研究单个干细胞和祖细胞克隆的谱系贡献，询问克隆是否对每个谱系（如粒细胞、T细胞、B细胞、树突细胞和肥大细胞）的贡献相等。我们已经开始研究这些克隆对其他组织（包括内皮和肌肉）的贡献，并开发了一种恒河猴心肌梗死模型，该模型使我们能够评估在梗死围期通过细胞因子动员原始细胞是否会导致MI后心肌再生和功能改善。到目前为止，没有证据表明有积极的益处，但我们继续研究不同的动员剂和时间表。我们已经发现了一种新的氧化铁颗粒，其被所研究的所有原代细胞类型非特异性地且高效地摄取，并且该颗粒已被用于标记，然后在心肌梗死的情况下通过心内或静脉内注射后通过MRI在体内追踪间充质干细胞。

Clinical and basic laboratory studies are directed at developing efficient and safe gene transduction and ex vivo manipulation strategies for hematopoietic cells, including stem and progenitor cells and lymphocytes, and using genetic marking techniques to answer important questions about in vivo hematopoiesis. In the rhesus model, shown to be the only predictive assay for human clinical results, we have focused on optimizing gene transfer to primitive stem and progenitor cells, and using genetic marking techniques to understand stem cell behavior in vivo.We have continued to further enhance gene transfer efficiency into rhesus engrafting cells, resulting in early levels of marked cells as high as 50-80%, with stable levels of 5-35% in all lineages, a range with clinical utility. We have found that actively-cycling transduced cells have an engraftment defect that can be corrected by a short culture on a fibronectin fragment with stem cell factor alone. The high levels have allowed us to continue to track the clonal contributions to hematopoiesis for the first time in a large animal model. We have utilized a new technology that allows simultaneous assessment of multiple clonal contributions to peripheral blood populations. We have found a different population of engrafting cells that contribute for the first 1-2 months post-transplantation, that are then replaced by a very stable set of over 80 clones that contribute to all lineages now for over 3 years. We have investigated the impact of cytokine therapy, radiation, and chemotherapy on the in vivo behavior of stem cell clones, using this powerful methodology. Thus far we have shown that prolonged cytokine treatment with either G-CSF or SCF does not significantly alter the number of stem cell clones contributing to hematopoiesis, nor result in detectable clonal exhaustion or recruitment. In contrast, treatment with low dose total body irradiation results in a significant decrease in stem cell clones contributing to peripheral blood lineages. Studies with busulfan are ongoing. We have also begun to carefully investigate the lineage contributions of individual stem and progenitor cell clones, asking whether clones contribute equally to each lineage such as granulocytes, T cells, B cells, dendritic cells and mast cells. We have begun to study the contributions of these clones to other tissues, including endothelium and muscle, and have developed a rhesus macaque myocardial infarction model that has allowed us to assess whether mobilization of primitive cells via cytokines in the peri-infarct period results in improved myocardial regeneration and function post MI. Thus far, there is no evidence for a positive benefit, but we continue to study different agents and schedules for mobilization. We have discovered a novel iron oxide particle that is taken up nonspecifically and highly efficiently by all primary cell types studied, and this particle has been utilized to label and then track mesenchymal stem cells in vivo via MRI follwing intracardiac or intravenous injection in the setting of a myocardial infarction.