RETINOIC ACID RECEPTOR A IN GRANULOPOIESIS AND LEUKEMIA

全反式维甲酸促进几种细胞的嗜酸性分化 骨髓细胞系并诱导急性白血病患者完全缓解 早幼粒细胞白血病（APL）。 在APL中，视黄酸受体基因 （RAR-α）易位到一个新的基因座PML，导致 融合基因PML-RAR-α的产生和表达。 但 RAR-α和PML-RAR-α在发展中的确切作用 中性粒细胞和白血病还不清楚。 本提案的具体目标 （1）测定视黄酸（RA）和视黄酸（RA 受体-α（RAR-α）在分化中起重要作用 （2）研究中性粒细胞的生物学后果， 融合基因PML-RAR-α在骨髓细胞中的表达。 将使用三种方法来确定RA和RAR-α是否起作用。 在中性粒细胞的分化中起重要作用。 一是 利用逆转录病毒载体表达“显性阴性”RAR-α， 能够分化成嗜中性粒细胞的造血细胞系，和 巨噬细胞 如果RAR-α是分化的关键， 中性粒细胞，显性阴性突变体对其功能的抑制 应该会破坏分化过程 第二，我们将使用相同的 逆转录病毒载体，以表达显性阴性 RAR-α在小鼠造血干细胞中的作用，以研究其对 体内造血 第三，将采用无血清培养体系 以确定RA在中性粒细胞发育中的需求。 到 研究表达的生物学后果， PML-RAR-α融合基因在骨髓细胞中的表达，我们将采用两个 战略布局 首先，将携带融合基因的逆转录病毒载体 用于感染能够进行嗜中性分化的骨髓细胞系 以确定该融合基因是否表现出显性 消极的活动。 第二，我们将感染小鼠骨髓干细胞， 用同样的逆转录病毒将干细胞移植到受者体内 小鼠来研究融合基因的致白血病潜力。 申请人的长期研究兴趣是分子控制 正常和肿瘤性中性粒细胞的分化。 总的来说， 拟议的研究使我们能够更多地了解RA的作用， 和RAR-α在造血中的作用

All-trans retinoic acid promotes neutrophilic differentiation of several myeloid cell lines and induces complete remission in patients with acute promyelocytic leukemia (APL). In APL, the gene of retinoic acid receptor (RAR-alpha) is translocated to a new locus PML, resulting in the generation and expression of a fusion gene PML-RAR-alpha. However, the exact roles of RAR-alpha and PML-RAR-alpha in the development of neutrophils and leukemia are unclear. The specific aims of this proposal are: (1) To determine If retinoic acid (RA) and retinoic acid receptor-alpha (RAR-alpha) play an essential role in the differentiation of neutrophils; (2) To investigate the biological consequences of the expression of the fusion gene PML-RAR-alpha in myeloid cells. Three approaches will be used to determine if RA and RAR-alpha play a crucial role in the differentiation of neutrophils. First, we will utilize a retroviral vector to express a "dominant negative" RAR-alpha in a hematopoietic cell line capable of differentiation into neutrophils and macrophages. If RAR-alpha is essential to the differentiation of neutrophils, suppression of its function by the dominant negative mutant should disrupt the differentiation process. Second, we will use the same retroviral vector to transduce and express the dominant negative RAR-alpha in mouse hematopoietic stem cells to study its effect on hematopoiesis in vivo. Third, a serum-free culture system will be used to determine the requirement of RA in the development of neutrophils. To investigate the biological consequences of the expression of PML-RAR-alpha fusion gene in myeloid cells, we will employ two strategies. First, a retroviral vector harboring the fusion gene will be used to infect myeloid cell lines capable of neutrophilic differentiation in response to RA to determine whether this fusion gene exhibits dominant negative activity. Second, we will infect murine bone marrow stem cells with the same retrovirus and transplant the stem cells into recipient mice to study the leukemogenic potential of the fusion gene. The applicant's long-term research interest is the molecular control of the differentiation of normal and neoplastic neutrophils. In summary, the proposed studies allow us to gain more insights into the roles of RA and RAR-alpha in hematopoiesis.