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.

在过去的几年中，研究发现了代谢对造血系统中干细胞行为和谱系规范的控制的至关重要性。尽管大部分重点都放在中间和能量代谢上，但痕量元素（例如铁）在造血细胞命运决策中的作用仍然不了解。在哺乳动物中，细胞铁稳态是由铁调节蛋白（IRP）-1和-2在转录后进行了策划的，该蛋白（IRP）-1和-2控制着编码细胞中关键铁代谢蛋白的mRNA命运。我们已经产生了一种新型的小鼠模型，从而在整个身体中急性破坏了IRP功能，并发现IRP是在成年期间维持中性粒细胞的物理水平所必需的。对造血系统的彻底分析表明，骨髓中嗜中性粒细胞分化的缺陷明显，祖细胞的积累正常未能朝着粒细胞谱系发展，而是导致看似“未成熟”的中性粒细胞。基于体内的相互骨髓移植实验和离体细胞培养模型，我们可以证明IRPs以细胞的固有方式支持中性粒细胞分化。这些结果发现了IRP在成年造血中的先前未认识的作用。现在，我们建议定义IRP缺陷中性粒细胞的功能和分子特征，并研究IRP的精确支持正常中性粒细胞。我们将首先评估缺乏IRP表达的“不成熟”中性粒细胞的形态和评估关键功能。同时，我们将在中性粒细胞分化的不同阶段介绍造血细胞的转录组。结合基因/功能富集聚类方法，这将有助于我们描述哪些细胞途径主要在IRP缺乏症中影响哪种细胞途径，因此对IRP的中性粒细胞功能可能很重要。然后，我们将使用基因救援实验离体和体内基因治疗来确定哪些候选途径将IRP功能与中性粒子联系起来。通过这项工作，我们希望揭示细胞中央稳态控制系统的新方面，并增强我们对代谢在造血作用的理解。