Molecular targeting of erythroid progenitor cells in normal and disordered human erythropoiesis

项目总结/摘要 红细胞生成缺陷最终可导致贫血，这是发病率和死亡率的主要原因 国际吧Diamond Blackfan贫血（DBA）是一种遗传性骨髓衰竭综合征， 红细胞生成障碍，目前只能用造血干细胞移植治愈。 除细胞因子外，免疫调节药物（IMiDs）来那度胺和泊马度胺 (Pom)和皮质类固醇，如地塞米松（Dex）是直接作用的主要药物 改善红细胞生成缺陷患者红细胞生成。尽管如此，它们的分子基础 对红系祖细胞和前体细胞的影响尚未完全了解。此外，并非所有DBA患者 对Dex有反应，只有40%的人有持续的反应，没有剂量限制性毒性。 本建议的主要研究重点是发展综合机制 了解Pom和GC对人红系祖细胞BFU-E和CFU-E的影响， 红细胞生成的总体目标是潜在地将它们联合收割机并治疗DBA中观察到的贫血， 其他疾病，以减少GC对患者的剂量限制性毒性。我们的初步数据显示， 在BFU-E阶段上调TEAD 2并沉默TGF-β。此外，Dex在CFU-E阶段起作用， 人类红细胞生成的模型。最后，与来自成人来源的CD 34+细胞的CFU-E不同，CFU-E 对地塞米松没有反应 我们推测，通过Pom沉默TGF-β通路将使Dex的作用最大化，从而 限制治疗患者所需的剂量及其毒性。在这里，我们建议研究分子 Pom和Dex在正常和异常红细胞生成的人类模型中靶向红系祖细胞 作为治疗贫血的概念证明。具体而言，我们将（1）确定 （2）通过流式细胞仪检测Dex对人CFU-Es的作用，探讨Dex对CFU-Es的作用机制。 糖皮质激素受体的动力学和细胞周期的整体调节，和（3）评估是否 Pom和Dex的组合刺激正常祖细胞和来自人的祖细胞中的红细胞生成。 DBA患者 这些研究将突出Pom和Dex在人体内作用的分子机制。 红细胞生成，并进一步了解正常和紊乱的红细胞生产和适当的 这些药物在改善骨髓衰竭综合征的临床管理中的用途。鉴于这些药物 已经被FDA批准用于多种血液疾病，我们进一步预期它们的联合使用 可能导致改善红细胞生成缺陷性疾病（如DBA）的临床管理。

Project Summary/Abstract Defects in erythropoiesis can ultimately lead to anemia, a major cause of morbidity and mortality worldwide. Diamond Blackfan anemia (DBA), an inherited bone marrow failure syndrome, is an example of disordered erythropoiesis and is currently only curable with hematopoietic stem cell transplantation. With the exception of cytokines, the immunomodulatory drugs (IMiDs) lenalidomide and pomalidomide (Pom) and corticosteroids such as dexamethasone (Dex) are the primary pharmacologic agents that directly improve red cell production in patients with erythropoietic defects. Nevertheless, the molecular basis for their effects on erythroid progenitors and precursors is not fully understood. In addition, not all patients with DBA respond to Dex, and only 40% of these have a sustained response without dose-limiting toxicity. The primary research focus of the present proposal is to develop comprehensive mechanistic understanding of effects of Pom and GC on the erythroid progenitors, BFU-E and CFU-E, during human erythropoiesis with the overarching goal to potentially combine them and treat the anemia seen in DBA and other diseases to reduce GC dose-limiting toxicity in patients. Our preliminary data reveal that Pom upregulates TEAD2 and silences the TGF-b at the BFU-E stage. In addition, Dex acts at the CFU-E stage in models of human erythropoiesis. Finally, unlike CFU-E derived from and adult source of CD34+ cells, CFU-E derived from cord blood are unresponsive to Dex. We hypothesize that silencing of TGF-b pathway by Pom will maximize the effects of Dex, thereby limiting the dose needed to treat patients, and its toxicity. Here we propose to investigate the molecular targeting of erythroid progenitors by Pom and Dex in human models of normal and disordered erythropoiesis as proof of concept for the treatment of anemia. Specifically, we will (1) determine the mechanism of action of Pom in human BFU-Es, (2) investigate the mechanism of action of Dex in human CFU-Es through the dynamics of the glucocorticoid receptor and global regulation of the cell cycle, and (3) evaluate whether the combination of Pom and Dex stimulates erythropoiesis in normal progenitor cells and progenitor cells from patients with DBA. These studies will highlight the molecular mechanisms of action of Pom and Dex during human erythropoiesis and further our understanding of normal and disordered red cell production and the appropriate use of these drugs in improved clinical management of bone marrow failure syndromes. Given that these drugs are already FDA-approved for a variety of hematological diseases, we further anticipate their combined use may result in improved clinical managements of disorders with defective red cell production such as DBA.