Regulation of Erythroid Cell Progenitors by the Nuclear Receptor Transcription Factor VDR

核受体转录因子 VDR 对红细胞祖细胞的调节

• 批准号: 9976495
• 负责人: Margaret H Baron
• 金额: $ 61.56万
• 依托单位: ICAHN SCHOOL OF MEDICINE AT MOUNT SINAI
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-04-06 至 2023-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9976495
• 关键词: ARNTL gene; ATAC-seq; Ablation; Adult; Agonist; Anemia; Animals; Bone Marrow; Calcitriol; Cell Culture Techniques; Cell Line; Cell Nucleus; Cells; Cholecalciferol; Chromatin; Circadian Rhythms; Clinical; Complex; Control Animal; DNA Binding; Development; Dexamethasone; Disease; Effectiveness; Embryo; Engineering; Erythrocyte Transfusion; Erythrocytes; Erythroid; Erythroid Progenitor Cells; Erythropoiesis; Fetal Liver; GATA1 gene; Gene Expression; Gene Expression Profiling; Genes; Genetic; Genetic Transcription; Glucocorticoid Receptor; Glucocorticoids; Growth; Hematological Disease; Hematopoietic; Knockout Mice; Knowledge; Lead; Leukemic Cell; Ligands; Mission; Modeling; Molecular Conformation; Molecular Target; Mutation; Nuclear Hormone Receptors; Nuclear Receptors; Output; Pathway interactions; Periodicity; Process; Production; Proteins; Public Health; Publishing; RNA; Receptor Activation; Receptor Signaling; Recovery; Regulation; Reticulocytosis; Role; Signal Pathway; Stress; Testing; Time; United States National Institutes of Health; Up-Regulation; Vitamin D3 Receptor; bone; circadian pacemaker; conditional mutant; erythroid differentiation; fetal; knock-down; mouse model; mutant; novel; novel therapeutics; progenitor; receptor expression; recruit; response; tool; transcription factor; virtual

ABSTRACT: The pathways that regulate the formation and differentiation of erythroid progenitors to red blood cells are incompletely understood. We found that the vitamin D receptor (Vdr) nuclear hormone transcription factor gene is expressed in fetal and adult stages but not at the embryonic stage of development and is downregulated during maturation. VDR activation by its ligand vitamin D3 results in conformational changes that stabilize the protein and induce its translocation into the nucleus, where it recruits coregulatory complexes. The VDR signaling pathway has been studied mostly in bone but has been largely unexplored in erythropoiesis: published studies were performed almost entirely in leukemic cell lines (not normal primary cells). Activation of Vdr signaling by the vitamin D3 agonist calcitriol increased the outgrowth of EryD colonies from fetal liver and adult bone marrow, maintained progenitor potential, and delayed erythroid maturation. The stimulation in growth of erythroid progenitors resulted in a large increase in the numbers of mature red blood cells. The early (CD71lo/neg) but not the late (CD71hi) EryD progenitor subset of Linneg cKit+ cells was responsive to calcitriol, independently of its calcemic effects. Activation of VDR could partially substitute for and synergize with the stress glucocorticoid dexamethasone in enhancing progenitor proliferation compared to either ligand alone, suggesting a role in stress erythropoiesis. This possibility is supported by our finding that an erythroid specific deletion in Vdr that interferes with DNA binding results in a reticulocytosis that occurs earlier and is more pronounced than in control animals in response to stress. RNA inhibition of Vdr expression abrogated the stimulation of early erythroid progenitor growth by calcitriol. These findings suggest that Vdr has a cell-intrinsic function in early erythroid progenitors. Activation of Vdr by calcitriol blocked the upregulation of erythroid transcription factor genes Gata1, Fog1 and Klf1. Intriguingly, circadian rhythm genes are upregulated by activation of Vdr and the glucocorticoid receptor Gr and oscillations in expression of the clock gene Per1 are promoted in erythroid progenitors. The clock gene Bmal1 is required for the proliferative response to dexamethasone. Therefore, the overarching hypothesis of this proposal is that Vdr and Gr regulate erythroid progenitors in part by modulating clock gene expression and have partially redundant functions. This application will use animal and cell culture models to explore the modulation of circadian clock gene expression by Gr and Vdr in erythroid progenitors and functional relationships between these two nuclear hormone receptor TFs. These studies may lead to the identification of novel molecular targets in erythroid progenitors that can be exploited to develop new therapies for anemias and other red cell disorders. The ability to modulate ex vivo expansion or differentiation of RBC progentors in new ways would have clear clinical utility.

摘要：调节红细胞祖细胞形成和分化为红细胞的途径 细胞尚不完全了解。我们发现维生素D受体（Vdr）核激素转录 因子基因在胎儿和成年阶段表达，但在发育的胚胎阶段不表达，并且 成熟过程中下调。 VDR 通过其配体维生素 D3 激活导致构象变化 稳定蛋白质并诱导其易位到细胞核中，在那里它招募共调节复合物。 VDR 信号通路主要在骨骼中进行研究，但在骨骼中尚未得到充分探索。 红细胞生成：已发表的研究几乎全部在白血病细胞系（不是正常的原代细胞）中进行 细胞）。维生素 D3 激动剂骨化三醇激活 Vdr 信号可增加 EryD 集落的生长 来自胎儿肝脏和成人骨髓，维持祖细胞潜力，并延迟红细胞成熟。这 刺激红系祖细胞生长导致成熟红细胞数量大量增加 细胞。 Linneg cKit+ 细胞的早期 (CD71lo/neg) 但晚期 (CD71hi) EryD 祖细胞亚群有反应 骨化三醇，与其血钙作用无关。 VDR 的激活可以部分替代和 与应激糖皮质激素地塞米松协同增强祖细胞增殖 任一配体单独存在，表明在应激性红细胞生成中发挥作用。我们的发现支持了这种可能性 Vdr 中的红细胞特异性缺失会干扰 DNA 结合，导致发生网织红细胞增多症 与对照动物相比，对压力的反应更早、更明显。 RNA 抑制 Vdr 表达 消除了骨化三醇对早期红系祖细胞生长的刺激。这些发现表明 Vdr 早期红系祖细胞的细胞固有功能。骨化三醇激活 Vdr 可阻止上调 红系转录因子基因 Gata1、Fog1 和 Klf1。有趣的是，昼夜节律基因是 通过 Vdr 和糖皮质激素受体 Gr 的激活以及时钟表达的振荡而上调 Per1 基因在红系祖细胞中得到促进。细胞增殖需要时钟基因 Bmal1 对地塞米松的反应。因此，该提案的总体假设是 Vdr 和 Gr 部分通过调节时钟基因表达来调节红细胞祖细胞，并具有部分冗余 功能。该应用程序将使用动物和细胞培养模型来探索生物钟的调节 Gr 和 Vdr 在红系祖细胞中的基因表达以及这两个核之间的功能关系 激素受体 TF。这些研究可能会导致红细胞中新分子靶标的鉴定 祖细胞可用于开发贫血和其他红细胞疾病的新疗法。能力 以新的方式调节红细胞祖细胞的离体扩增或分化将具有明确的临床实用性。