Oxidative stress mechanisms regulating gamma-globin gene transcription in sickle cell disease

氧化应激调控镰状细胞病G-珠蛋白基因转录的机制 摘要： 镰状细胞病（SCD）是影响β-珠蛋白表达的最常见的遗传性单基因疾病 基因，导致镰状红细胞（RBC）的产生。SCD患者患有 严重的贫血和痛苦的血管闭塞性危象，这两者都因氧化应激反应的增加而加剧。 应力胎儿血红蛋白（HbF）的正常但发育沉默的γ-珠蛋白基因的诱导 表达减少RBC镰状化介导的血管闭塞和贫血，从而改善 SCD的临床严重程度。减少氧化应激也改善SCD表型严重程度。然而 有效的治疗选择仍然有限。了解红细胞的发病机制 调节氧化应激的机制和参与沉默γ-珠蛋白基因的因子，是重要的 对SCD患者的价值。我们的数据揭示了氧化应激介导物在 红细胞镰状化和调节抑制γ-珠蛋白基因的转录调节机制 以及与红系中γ-珠蛋白到β-珠蛋白基因转换相关的表观遗传酶组分 祖先在这里，为了扩展我们的研究，我们将在体外和体内遗传和/或化学 使用SCD小鼠模型操纵这些氧化应激介质和调节途径， 并确定它们对γ-珠蛋白基因调控的影响，从而镰状化，以及它们的机制， 对镰状红细胞形成过程中γ-珠蛋白基因沉默的转录调节机制的作用 生产我们还将确定这些介质在表观遗传DNA和组蛋白中的作用。 γ-珠蛋白相关修饰 在镰状红细胞产生过程中的β-珠蛋白基因转换。因为 应激性红细胞生成补偿了红细胞氧化损伤引起的贫血，我们将进一步 证实这些氧化应激介质对脾细胞应激性红细胞生成的影响， 造血组织，并检查它们在慢性红细胞应激反应中的作用，特别是在 红系终末成熟和去核。我们坚信，我们的研究将提供新的 以及对γ-珠蛋白基因沉默和γ-珠蛋白 β-珠蛋白基因开关，以及无效的红细胞成熟和去核。我们长久以来- 长期目标是鉴定可治疗的镰状红细胞异常以改善SCD的病理生理学。在 此外，我们的研究将为更合理的治疗方法奠定基础， 缓解SCD临床症状。

Oxidative stress mechanisms regulating g-globin gene transcription in sickle cell disease Abstract: Sickle cell disease (SCD) is the most common inherited monogenic disorder affecting the β-globin gene, leading to the production of sickled-shaped red blood cells (RBCs). Patients with SCD suffer from severe anemia and painful vasoocclusive crises, which are both exacerbated by increased oxidative stress. Induction of normal, but developmentally silenced γ-globin gene of fetal hemoglobin (HbF) expression reduces RBC sickling-mediated vasoocclusion, and anemia, consequently ameliorating clinical severity of SCD. Reducing oxidative stress also improves SCD phenotypic severity. Yet effective treatment options remain limited. Understanding the pathogenesis of the erythroid mechanisms regulating oxidative stress and factors engaged in silencing γ-globin gene, is of substantial value to SCD patients. Our data uncovered an unanticipated role for mediators of oxidative stress in RBC sickling, and in regulating the transcriptional regulatory machinery that represses γ-globin genes as well as epigenetic enzyme components associated with γ-globin to β-globin gene switch in erythroid progenitors. Here, to extend our studies, we will in vitro and in vivo genetically and/or chemically manipulate these mediators of oxidative stress and the regulated pathways using a SCD mouse model, and determine their effects on γ-globin gene regulation, and thus sickling, and their mechanism of action on the transcriptional regulatory machinery that silences γ-globin gene during sickle RBC production. We will also determine the contribution of these mediators in epigenetic DNA and histone modifications associated with γ-globin to β-globin gene switch during sickle RBC production. Because stress erythropoiesis compensates for anemia caused by oxidative damage to the RBCs, we will further validate the effects of these mediators of oxidative stress on stress erythropoiesis in splenic hematopoietic tissue and examine their role in chronic erythroid stress-response, specifically in erythroid terminal maturation and enucleation. We strongly believe that our studies will provide novel and unprecedented insights into the exact mechanisms regulating γ-globin gene silencing and γ-globin to β-globin gene switch in SCD, as well as ineffective erythroid maturation and enucleation. Our long- term goal is to identify remediable sickle erythroid abnormalities to improve SCD pathophysiology. In addition, our studies will lay the foundation for more rational approaches to therapies that better alleviate SCD clinical symptoms.