ROLE OF THE PNH PHENOTYPE IN LEUKEMIC TRANSFORMATION

PNH 表型在白血病转化中的作用

• 批准号: 6227475
• 负责人: Monica Bessler
• 金额: $ 30.54万
• 依托单位: BARNES-JEWISH HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-01-20 至 2005-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6227475
• 关键词: acute myelogenous leukemia; aplastic anemia; apoptosis; disease /disorder model; erythroleukemia; genetically modified animals; glycosylphosphatidylinositols; glycosyltransferase; hematopoiesis; hematopoietic stem cells; laboratory mouse; paroxysmal nocturnal hemoglobinuria; spinal cord disorders; viral carcinogenesis

DESCRIPTION (adapted from the applicant's abstract): Paroxysmal nocturnal hemoglobinuria (PNH) is a blood disorder, which is caused by the clonal expansion of a hematopoietic progenitor cell that carries a somatic mutation in the X-linked PIGA gene. It presented classically with hemoglobinuria due to intravascular hemolysis, thrombotic complications, and pancytopenia. The PIGA gene encodes a protein subunit of a glycosyltransferase essential in the synthesis of glycosyl phosphatidylinositol (GPI) anchor molecules. Patients with PNH therefore have a proportion of blood cells deficient in all GPI-linked surface molecules. PNH is frequently found in patients with aplastic anemia (AA) and in patients with myelodysplasia (MDS). Although not a neoplastic disease on its own, patients with PNH have an increased risk of developing acute myeloid leukemia (AML). Promoted by the clinical association of PNH with AA, MDS, and AML, we raised the hypothesis that a PIGA gene mutation alone does not cause clonal expansion or leukemic transformation. But due to their inability to like certain proteins to the cell surface through a GPI-anchor PNH cells escape immuno surveillance and cell death that causes bone marrow aplasia in AA and controls neoplastic cell growth in early leukemogenesis. In the proposed research we will use a mouse model that closely mimics the human disease and investigate the association of PNH with MDS and AML. We will obtain mice with blood cells lacking GPI-linked proteins by disrupting the murine Piga gene in early hematopoietic progenitor cells in the bone marrow using the Cre-loxP system. By this approach we will generate two types of mice, one with all blood cells deficient in GPI-linked proteins whereas the other will have both PIGA (+) and PIGA(-) circulating blood cells. We will then compare PIGA(+) and PIGA(-) hematopoiesis in these mice in vitro and in vivo under a variety of circumstances, including the administration of stimuli that trigger cell death along with agents known to cause leukemia transformation. Competition between cells expressing wild type Piga and those expressing the recombined Piga allele will enable us to uncover even subtle differences in cell death and proliferation in any stages of hematopoietic differentiation. These experiments will demonstrate whether PIGA(-) blood cells are more resistant to specific stimuli that activate apoptotic cell death and whether mice with PIGA(-) blood cells develop leukemia earlier and more frequent compared to mice with phenotypically normal blood cells. In this way we hope to identify the factors that differentially influence growth and death of PNH and normal hematopoietic progenitor cells and to elucidate mechanisms that may lead to leukemia transformation in patients with PNH. The availability of a mouse model for PNH will provide us with a powerful tool to test new therapeutic agents for the treatment of PNH, PNH/MDS, PNH,AML and possibly other clonal blood disorders.

描述（改编自申请人的摘要）：阵发性夜间 血红蛋白尿 (PNH) 是一种血液疾病，由克隆性血红蛋白尿引起 携带体细胞突变的造血祖细胞的扩增 X连锁的PIGA基因。它典型地表现为血红蛋白尿，原因是 血管内溶血、血栓并发症和全血细胞减少症。 PIGA 基因编码糖基转移酶必需的蛋白质亚基 糖基磷脂酰肌醇（GPI）锚定分子的合成。患者 因此，患有 PNH 的人有一定比例的血细胞缺乏所有 GPI 相关的基因。 表面分子。 PNH 常见于再生障碍性贫血患者 (AA) 和骨髓增生异常 (MDS) 患者。虽然不是肿瘤 就其本身而言，PNH 患者患上这种疾病的风险会增加 急性髓系白血病（AML）。 在 PNH 与 AA、MDS 和 AML 的临床关联的推动下，我们提出 PIGA 基因突变本身不会导致克隆扩增的假设 或白血病转化。但由于他们无法喜欢某些蛋白质 通过 GPI 锚定到细胞表面 PNH 细胞逃避免疫监视 和细胞死亡导致 AA 中的骨髓再生障碍并控制肿瘤 早期白血病发生中的细胞生长。 在拟议的研究中，我们将使用密切模仿的小鼠模型 人类疾病并调查 PNH 与 MDS 和 AML 的关联。我们将 通过破坏血细胞中缺乏 GPI 连接蛋白的小鼠 小鼠骨髓早期造血祖细胞中的 Piga 基因 使用 Cre-loxP 系统。通过这种方法，我们将产生两种类型的小鼠， 一个的所有血细胞都缺乏 GPI 连接蛋白，而另一个则 将同时具有 PIGA (+) 和 PIGA(-) 循环血细胞。我们随后将 比较这些小鼠体内和体外的 PIGA(+) 和 PIGA(-) 造血功能 在各种情况下，包括施加刺激 与已知导致白血病转化的药物一起触发细胞死亡。 表达野生型 Piga 的细胞与表达 Piga 的细胞之间的竞争 重组的 Piga 等位基因将使我们能够发现甚至细微的差异 造血分化的任何阶段的细胞死亡和增殖。 这些实验将证明 PIGA(-) 血细胞是否更 对激活细胞凋亡的特定刺激具有抵抗力，以及是否 具有 PIGA(-) 血细胞的小鼠更早且更频繁地患上白血病 与具有正常血细胞表型的小鼠相比。我们希望通过这种方式 确定对 PNH 生长和死亡有不同影响的因素， 正常造血祖细胞并阐明可能导致的机制 PNH 患者的白血病转化。鼠标的可用性 PNH 模型将为我们提供测试新疗法的强大工具 用于治疗 PNH、PNH/MDS、PNH、AML 和可能的其他克隆性疾病的药物 血液疾病。