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：调节红血上红细胞的形成和分化的途径 细胞不完全理解。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人阶段表达，但在发育的胚胎阶段不表达，IS 成熟过程中下调。 VDR通过配体维生素D3激活导致构象变化 稳定蛋白质并诱导其易位到核中，在那里它募集了核调节络合物。 VDR信号通路主要是在骨骼中研究的，但在很大程度上没有探索 红细胞生成：已发表的研究几乎完全是在白血病细胞系中进行的（不是正常的原发性 细胞）。维生素D3激动剂钙化激活VDR信号的激活增加了埃里德菌落的生长 从胎儿肝脏和成年骨髓中，保持祖细胞的潜力，并延迟了红细胞的成熟。这 刺激红系祖细胞的生长导致成熟的红血数量大量增加 细胞。 linneg ckit+细胞的早期（CD71LO/neg），但不是晚期（CD71HI）的Eryd祖细胞子集反应性 对于钙化，与其钙化作用无关。 VDR的激活可以部分替代和 与应力糖皮质激素地塞米松协同作用，以增强祖细胞增殖 单独的配体都表明在压力红细胞生成中起作用。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结合会导致发生的网状细胞增多 响应压力，比对照动物更为明显。 RNA抑制VDR表达 废除了通过骨化三醇刺激早期红细胞祖细胞生长。这些发现表明VDR有 早期红细胞祖细胞中的细胞中性功能。通过钙三醇激活VDR，阻止了 红细胞转录因子基因GATA1，FOG1和KLF1。有趣的是，昼夜节律基因是 由VDR和糖皮质激素受体GR的激活以及时钟表达中的振荡上调 基因PER1在红系祖细胞中促进。时钟基因BMAL1是增生性的 对地塞米松的反应。因此，该提议的总体假设是VDR和GR 通过调节时钟基因表达并部分冗余，部分调节红细胞祖细胞 功能。该应用将使用动物和细胞培养模型来探索昼夜节律的调节 GR和VDR在红细胞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。这些研究可能导致鉴定在红斑中的新分子靶标 可以利用的祖细胞为贫血和其他红细胞疾病开发新的疗法。能力 通过新的方式调节RBC进度的离体扩展或分化将具有明显的临床实用性。