FOXO3 Regulation of Normal and Stress Erythropoiesis

摘要 慢性氧化应激加剧了一系列红系疾病，包括血红蛋白疾病， 真性红细胞增多症和炎症性贫血；然而，红细胞慢性应激所涉及的机制- 对此的反应相对来说仍未被探索。此外，它们对正常生理过程的影响是 未知。我们的重点一直放在动态平衡转录因子FOX03上，它对 红细胞生成氧化还原状态的调节。我们最近展示了FOXO_3对终端的关键作用 红细胞生成中的成熟和去核。另一方面，我们的研究表明， FOXO_3显著改善红细胞遗传性疾病--地贫模型的贫血 以氧化还原失衡为核心的细胞。鉴于FOX03函数的广泛范围，其影响的程度 红血球的生成可能取决于上下文。我们的首要目标是测试慢性 FOXO_3介导的应激反应通路的激活对有害的 红系疾病的病理生理学。为了检验这一假设，我们建议使用新的定量 人类红细胞的成像方法、基因组高通量方法和体外培养 以及在纯遗传背景下产生的结合功能丧失和功能获得的小鼠模型 实现以下独立但高度互补和协同的目标的方法：(目标1)： 研究FOXO_3调节红细胞去核的机制；(目标2)： 阐明FOXO_3在β-地中海贫血红细胞生成中的作用。这些联合研究将阐明 慢性激活FOXO_3介导的应激反应如何改变正常生理过程和 加重β-地中海贫血，特别是更广泛的红系疾病。

SUMMARY Chronic oxidative stress exacerbates an array of erythroid disorders, including hemoglobinopathies, polycythemia vera and anemia of inflammation; yet the mechanisms engaged by erythroid chronic stress- response remain relatively unexplored. In addition, their impact on normal physiological processes is unknown. Our focus has been on the homeostatic transcription factor FOXO3 which is essential for the regulation of the erythropoiesis redox state. We showed recently that FOXO3 is critical for terminal maturation and enucleation in erythropoiesis. On the other hand, our studies indicate that the loss of FOXO3 improves significantly anemia in a model of ß-thalassemia that is a genetic disorder of erythroid cells with redox imbalance at its core. Given the broad scope of FOXO3 functions, the extent of its impact on erythropoiesis may depend on the context. Our overarching goal is to test the hypothesis that chronic activation of FOXO3-mediated stress-response pathways contributes significantly to the deleterious pathophysiology of erythroid disorders. To test this hypothesis we propose to employ novel quantitative imaging methodologies, genomic high-throughput approaches, and in vitro cultures of human erythroblasts and mouse models generated on pure genetic background combined with loss- and gain-of-function approaches to achieve the following independent yet highly complementary and synergistic aims: (Aim 1): To investigate mechanisms whereby FOXO3 regulates erythroblast enucleation; (Aim 2): To elucidate the role of FOXO3 in β-thalassemic erythropoiesis. These combined studies will elucidate how chronic activation FOXO3-mediated stress response may alter normal physiological processes and aggravate β-thalassemia specifically and more broadly erythroid disorders.