RETINOIC ACID RECEPTORS AND MYELOPOIESIS

维甲酸(RA)的多种生物学效应被认为是 通过特定的RA受体(RARs)介导。RA诱导 急性白血病患者白血病细胞的粒细胞分化 早幼粒白血病(APL)。大多数RA敏感的APL样本都含有 特异的15：17染色体易位，涉及RAR-α 并导致RAR-α融合转录本异常(指定为 PML-RAR-Alpha)。新陈代谢综合征发生的病理生理后果 这种异常的PML-RAR-α融合转录本及其与 白血病的发生目前尚不清楚。也不知道它扮演着什么角色，如果 无论如何，RA可能在调节正常造血方面发挥作用。这项建议 计划通过利用逆转录病毒介导的基因来解决这些问题 转导异常的RA受体结构进入 造血细胞系和正常造血干细胞。这个 需要解决的具体问题包括： 特异靶I)PML-RAR-α的异常表达 融合基因与APL的发病机制有关？ 目的是为了探讨骨质疏松症发生的病理生理后果。 PML-RAR-α融合基因，我们将利用逆转录病毒介导的基因 转导在RA敏感和RA敏感的RA中表达融合基因 并比较耐药细胞系的分化情况。 未感染的细胞与逆转录病毒感染的细胞对RA的反应。我们还将 携带逆转录病毒载体的小鼠造血干细胞感染 用PML-RAR-α融合基因研究人白血病细胞的致白血病潜能 体内存在异常的RA受体。 特定目的II)RA和RA受体(RAR-α)在 调节正常的造血功能？ 多条间接证据表明，RA和RA受体 (RAR-α)可能参与调节正常的造血。至 直接接近这个问题，我们将确定对 引入突变型“显性阴性”的造血分化 将RAR-α导入造血细胞系，模拟以下几个方面 正常的造血以及进入正常的小鼠造血干细胞 体内的细胞。 尽管我们建议的研究仅限于造血细胞，但它们 可能最终提供对正常或异常RA角色的洞察 受体可能在其他人类恶性肿瘤的发展过程中发挥作用。

The diverse biologic effects of retinoic acid (RA) are thought to be mediated through specific RA receptors (RARs). RA induces the granulocytic differentiation of leukemia cells in patients with acute promyelocytic leukemia (APL). Most RA-sensitive APL samples harbor a specific 15:17 chromosome translocation, which involves the RAR-alpha locus and leads to an aberrant RAR-alpha fusion transcript (designated PML-RAR-alpha). The pathophysiologic consequences of the generation of this aberrant PML-RAR-alpha fusion transcript and its relationship to leukemogenesis are presently unclear. It is also unknown what role, if any, RA might play in regulating normal hematopoiesis. This proposal plans to approach these questions by utilizing retroviral-mediated gene transduction to transfer aberrant RA receptor constructs into hematopoietic cell lines and normal hematopoietic stem cells. The specific questions to be addressed include the following: Specific Aim I) How does the expression of the aberrant PML-RAR-alpha fusion gene relate to the pathogenesis of APL? To explore the pathophysiologic consequences of the generation of the PML-RAR-alpha fusion gene, we will utilize retrovirus-mediated gene transduction to express this fusion gene in both RA-sensitive and RA- resistant hemopoietic cell lines and compare the differentiation of the uninfected vs. retrovirus-infected cells in response to RA. We will also infect murine hemopoietic stem cells with a retroviral vector harboring the PML-RAR-alpha fusion gene to study the leukemogenic potential of this aberrant RA receptor in vivo. Specific Aim II) What roles do RA and RA receptors (RAR-alpha) play in regulating normal hematopoiesis? Several lines of indirect evidence suggest that RA and the RA receptor (RAR-alpha) may be involved in regulating normal hematopoiesis. To directly approach this question we will determine the effect on hematopoietic differentiation of introducing a mutant "dominant negative" RAR-alpha into a hematopoietic cell line that mimics several aspects of normal hematopoiesis as well as into normal murine hematopoietic stem cells in vivo. Although our proposed studies are confined to hematopoietic cells, they may eventually provide insight into the role normal or abnormal RA receptors might play in the development of other human malignancies.