Altering Fate of Hematopoietic and Neural Stem Cells

描述(申请人提供)：干细胞可塑性的概念最近被许多所谓的组织特异性干细胞呼叫诱骗成其他组织表型的例子所支持。改变组织特异性干细胞的命运，诱导转分化，已经在许多不同的生物测试中被报道，使用各种细胞培养和体内条件和操作，在同一研究中没有系统和直接地比较来自不同组织的不同干细胞群体。这一建议在三组实验中建立了造血干细胞和神经干细胞的转分化能力的“面对面”比较，这些实验将在体外建立改变造血和神经干细胞命运的能力，胚胎和成年小鼠的体内研究将测试与表观遗传因素有关的假说，这些因素控制着从造血和神经干细胞结构中分离出来的干细胞的命运选择和终末分化它们在体外和体内的转分化能力将使用敏感的表型和功能分析进行评估。为了确认它们完全转化和整合到新的宿主环境中，特定的目标1将确定来自出生后和成年小鼠大脑的候选干细胞是否确实表现出真正的干细胞行为，观察造血干细胞的既定属性，包括自我更新和长期克隆、多谱系重建。这些初始种群将使用特定的表面抗原进行分类和浓缩，以确定培养对发育潜力的影响。具体目标2将着眼于造血干细胞在体外和体内对神经信号的反应能力，通过贡献整合到发育中的功能细胞，并重新繁殖成人神经系统。最后，目标3将检验神经干细胞足够可塑性以对造血信号做出反应的假设，在它们被移植到类胚体、胎鼠和辐射消融的骨髓后，这里将使用的“头对头”测试系统将确定转分化方法在建立针对许多不同人类疾病的新细胞疗法方面的潜在用处。包括各种血液和大脑疾病中的细胞丢失和增殖，在我们可以了解血细胞成为脑细胞的潜力之前，这是一个深刻的转分化例子，为当前的细胞替代治疗提供了许多替代方法，有必要建立起始细胞群体的严谨性，并了解参与血/脑干细胞增殖的因素、对命运的承诺和分化。

DESCRIPTION (provided by applicant): The notion of stem cell plasticity has been recently supported by numerous examples of so-called tissue specific stem calls being coaxed into other tissue phenotypes. Altering fate of tissue-specific stem cells, inducing transdifferentiation, has been reported in many different bioassays, using a variety of cell culture and in vivo conditions and manipulations, without a systematic and direct comparison of different stem cell populations from different tissues in the same study. This proposal sets up a "head-to-head" comparison of transdifferentiation abilities of hematopoietic and neuropoietic stem cells in three sets of experiments that will establish the ability to alter the fate of hematopoietic and neuropoietic stem cells In vitro, embryonic and adult mouse in vivo studies will test hypotheses related to epigenetic factors that control the choice of fate as well as terminal differentiation of stem cells isolated from hematopoietic and neuropoietic structures Their ability to transdifferentiate, both in vitro and in vivo, will be evaluated using sensitive phenotypic and functional analyses, to confirm their full conversion and integration into their new host environments Specific Aim 1 will determine whether a candidate stem cell from the postnatal and adult mouse brain in fact exhibits true stem cell behaviors, looking at established attributes of hematopoietic stem cells including self-renewal and long-term clonal, multilineage reconstitution. This starting population will be sorted and enriched using specific surface antigens in order to determine the affects of culturing on developmental potential. Specific Aim 2 will look at the ability of hematopoietic stem cells to respond to neural cues in vitro and in vivo, by contributing functional cells that integrate within the developing, and repopulating adult nervous system Finally, Aim 3 will test the hypothesis that neural stem cells are plastic enough to respond to hematopoietic cues, following their transplantation into embryoid bodies, fetal mice, and radiation-ablated bone marrow The "head-to-head" assay systems to be used here will determine the potential usefulness of transdifferentiation approaches for establishing new cell therapeutics for many different human diseases, including cell loss as well as hyperplasia in a variety of blood and brain disorders Before we can understand the potential of blood ceils to become brain cells, a profound example of transdifferentiation that offers numerous alternative approaches to current cell replacement therapies, it is necessary to establish sternness of starting cell populations, and also understand factors involved in blood/brain stem cell proliferation, commitment to fate, and differentiation.