Unravelling the importance of Iron Regulatory Proteins for Granulopoiesis

揭示铁调节蛋白对粒细胞生成的重要性

• 批准号: 448829424
• 负责人: Dr. Bruno Galy, Ph.D.
• 金额: --
• 依托单位: Abteilung Virus-assoziierte Karzinogenese
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2020
• 资助国家: 德国
• 起止时间: 2019-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/448829424?language=en
• 关键词: Unravelling; importance; Iron; Regulatory; Proteins

Research in the past few years uncovered the critical importance of metabolism for the control of stem cell behavior and lineage specification in the hematopoietic system. While much of the focus has been on intermediary and energy metabolism, the role of trace elements such as iron in hematopoietic cell fate decisions remains ill understood. In mammals, cellular iron homeostasis is orchestrated posttranscriptionally by the iron regulatory proteins (IRP)-1 and -2, which control the fate of mRNAs encoding key iron metabolism proteins in the cell. We have generated a novel mouse model enabling acute disruption of IRP function in the entire body, and discovered that IRPs are required for maintaining physiological levels of neutrophils during adulthood. A thorough analysis of the hematopoietic system revealed marked defects in neutrophil differentiation in the bone marrow, with accumulation of progenitor cells that fail to progress normally towards the granulocytic lineage and instead give rise to seemingly “immature” neutrophils. Based on reciprocal bone marrow transplantation experiments in vivo and an ex vivo cell culture model, we could demonstrate that IRPs support neutrophil differentiation in a cell intrinsic manner. These results uncover a previously unrecognized role for the IRPs in adult hematopoiesis. We now propose to define the functional and molecular characteristics of IRP-deficient neutrophils, and investigate how precisely the IRPs support normal neutropoiesis. We will first assess the morphology and assay key functions of “immature” neutrophils lacking IRP expression. In parallel, we will profile the transcriptome of hematopoietic cells at different stages of neutrophil differentiation. Combined with gene/functional enrichment clustering approaches, this will help us delineate which cellular pathways are primarily affected in IRP deficiency and thus potentially important for the neutropoietic functions of the IRPs. We will then use gene rescue experiments ex vivo and in vivo gene therapy to determine which of the candidate pathways links IRP function to neutropoiesis. With this work we wish to unveil new facets of a central homeostatic control system in the cell and enhance our understanding of the role of metabolism in hematopoiesis.

过去几年的研究揭示了代谢对于造血系统中干细胞行为和谱系规范的控制至关重要，虽然大部分注意力都集中在中间代谢和能量代谢上，但铁等微量元素在造血系统中的作用。在哺乳动物中，细胞的铁稳态是由铁调节蛋白 (IRP)-1 和 -2 在转录后协调的，它们控制着细胞中编码关键铁代谢蛋白的 mRNA 的命运。我们建立了一种新型小鼠模型，能够急性破坏整个身体的 IRP 功能，并发现 IRP 是维持成年期中性粒细胞生理水平所必需的。对造血系统的彻底分析揭示了骨髓中中性粒细胞分化的明显缺陷。根据体内相互骨髓移植实验，祖细胞的积累无法正常向粒细胞谱系发展，而是产生看似“不成熟”的中性粒细胞。和离体细胞培养模型，我们可以证明 IRP 以细胞内在的方式支持中性粒细胞分化。这些结果揭示了 IRP 在成人造血中以前未被认识的作用。我们现在建议定义 IRP 缺陷的功能和分子特征。中性粒细胞，并研究 IRP 如何精确地支持正常中性粒细胞生成 我们将首先评估缺乏 IRP 表达的“未成熟”中性粒细胞的形态和关键功能。我们将分析中性粒细胞分化不同阶段的造血细胞转录组，结合基因/功能富集聚类方法，这将帮助我们描绘哪些细胞途径主要受到 IRP 缺乏的影响，从而对 IRP 的中性粒细胞生成功能具有潜在的重要性。然后，我们将使用离体基因拯救实验和体内基因治疗来确定哪些候选途径将 IRP 功能与中性粒细胞生成联系起来，我们希望通过这项工作揭示一个中心的新方面。细胞内的稳态控制系统，增强了我们对代谢在造血作用中的作用的理解。