RETINOIC ACID RECEPTORS AND HEMATOPOIESIS

性状：（改编自研究者摘要）维甲酸（RA） 和RA受体（RAR）参与调节生长， 多种不同细胞类型的分化。为了探索 研究人员利用逆转录病毒 携带显性负RAR干扰正常 在不同造血细胞中的内源RAR活性。他们有 在正常小鼠骨髓培养物中观察到， 内源性RA受体活性的存在下，不同的 造血生长因子导致建立 在中性粒细胞的特定阶段冷冻的造血细胞系 分化研究人员希望进一步扩展这些研究 如下定义RA受体在造血中的作用。具体 目的1：确定体外培养的淋巴造血EML细胞是否具有 在受辐射的小鼠体内发挥造血干细胞的功能。通过感染 正常小鼠骨髓与逆转录病毒载体携带显性 由于RA受体构建体呈阴性，研究人员重复性地发现 衍生的干细胞因子依赖性细胞系， 自我更新淋巴造血祖细胞的特性 （指定为EML）。研究者将正式评估股骨柄 通过评估这些培养的EML细胞的细胞活性， 在受辐射的同基因小鼠体内充当造血干细胞。 具体目标2：利用显性阴性RA受体逆转录病毒 建立造血生长因子依赖性造血细胞的载体 干细胞系为进一步探讨RA受体在调节细胞凋亡中的作用， 造血干细胞谱系的定型和分化 和祖细胞，研究人员将培养骨髓感染 用显性阴性RA受体逆转录病毒构建体， 特异性造血生长因子，包括IL-1，IL-3，IL-4，IL-6， flk 2/flt 3配体和TPO，试图建立其他生长因子 在造血的不同阶段冷冻的依赖细胞系 分化具体目标3：利用显性阴性RA 受体逆转录病毒载体，以建立生长因子依赖性 淋巴造血祖细胞系。具体 目的4：确定RA受体拮抗剂在自身中的作用 更新和增殖培养的小鼠和人类干细胞。的 研究人员将使用显示RA受体的合成类维生素A 拮抗剂活性，试图优化体外条件， 增强造血干细胞的自我更新和增殖， 阻碍其分化。

DESCRIPTION: (Adapted from investigator's abstract) Retinoic acid (RA) and RA receptors (RARs) are involved in regulating the growth and differentiation of multiple different cell types. To explore the role of RA in hematopoiesis, the investigators have utilized retroviral vectors harboring a dominant negative RAR to interfere with normal endogenous RAR activity in different hematopoietic cells. They have observed in cultures of normal mouse bone marrow that inhibiting endogenous RA receptor activity in the presence of different hematopoietic growth factors results in the establishment of hematopoietic cell lines frozen at specific stages of neutrophil differentiation. The investigators wish to further extend these studies defining the role of RA receptors in hematopoiesis as follows. Specific Aim 1: Determine whether the cultured lymphohematopoietic EML cells can function as hematopoietic stem cells in irradiated mice. By infecting normal mouse bone marrow with a retroviral vector harboring a dominant negative RA receptor construct, the investigators have reproducibly derived stem cell factor-dependent cell lines that display characteristics of self-renewing lympho-hematopoietic progenitors (designated EML). The investigators will formally evaluate the stem cell activity of these cultured EML cells by assessing their ability to act as hematopoietic stem cells in vivo in irradiated syngeneic mice. Specific Aim 2: Utilize the dominant negative RA receptor retroviral vector to establish hematopoietic growth factor dependent hematopoietic stem cell lines. To further explore the RA receptors in regulating the commitment and differentiation of lineages of hematopoietic stem cells and progenitors, the investigators will culture bone marrow infected with the dominant negative RA receptor retroviral construct with specific hematopoietic growth factors including IL-1, IL-3 IL-4, IL-6, flk2/flt3 ligand and TPO in an attempt to establish other growth factor dependent cell lines frozen at different stages of hematopoietic differentiation. Specific Aim 3: Utilize the dominant negative RA receptor retroviral vector to establish growth factor dependent lymphohematopoietic progenitor lines from human bone marrow. Specific Aim 4: Determine the effect of RA receptor antagonists in the self renewal and proliferation of cultured mouse and human stem cells. The investigators will use synthetic retinoids exhibiting RA receptor antagonist activity in attempts to optimize in vitro conditions that enhance self-renewal and proliferation of hematopoietic stem cells while blocking their differentiation.