Enhancing hematopoiesis through modulation of a histone methyltransferase: evaluating a new MLL1 gain-of-function animal model

通过调节组蛋白甲基转移酶增强造血功能：评估新的 MLL1 功能获得动物模型

• 批准号: 10017193
• 负责人: Patricia Ernst
• 金额: $ 27.99万
• 依托单位: UNIVERSITY OF COLORADO DENVER
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-09-15 至 2022-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10017193
• 关键词: Acute leukemia; Adult; Animal Model; Animals; Autoimmune Diseases; Basic Science; Biological Assay; Biological Models; Blood Cells; Blood specimen; Bone Marrow; Cardiovascular system; Cell Maintenance; Cells; Chromosomal translocation; Clinical; Clinical Trials; Data; Development; Disease; Doxycycline; Embryo; Embryonic Development; Engineering; Engraftment; Equilibrium; Future; Gene Expression; Genetic Transcription; Grant; Hematologic Neoplasms; Hematopoiesis; Hematopoietic; Hematopoietic Stem Cell Transplantation; Hematopoietic System; Hematopoietic stem cells; Homeostasis; Human; In Vitro; Individual; Infection; Learning; Link; MLL gene; Maintenance; Modeling; Molecular; Mus; Organism; Output; Pathway interactions; Patients; Phenotype; Physiology; Population; Proteins; Proto-Oncogenes; Research Personnel; Resistance; Role; Signal Transduction; Solid Neoplasm; Source; Stem Cell Development; Testing; Time; Tissues; Transgenic Organisms; Translating; Transplantation; Umbilical Cord Blood; Work; base; bone marrow failure syndrome; cell preparation; cell type; expectation; experimental study; fetal; gain of function; gene function; hematopoietic differentiation; hematopoietic stem cell differentiation; hematopoietic stem cell expansion; hematopoietic stem cell self-renewal; hematopoietic tissue; histone methyltransferase; human stem cells; improved; improved functioning; in vivo; leukemia; loss of function; mortality; mouse model; novel; overexpression; preservation; prevent; progenitor; programs; selective expression; self-renewal; stem cells; transcription factor; transcriptome; translational approach

PROJECT SUMMARY To maintain ongoing homeostasis, hematopoietic stem cells (HSCs) possess elaborate mechanisms to balance self-renewal, proliferation and differentiation. During development and after infection HSCs adjust self-renewal versus differentiation to expand to meet but not overshoot the needs of the organism. Understanding how HSCs modulate this balance is critical for manipulating HSCs ex vivo for improved use in transplantation. To improve our understanding balancing HSC self-renewal with other needs, we have studied molecular pathways connected to the proto-oncogene, MLL1, due to its unique ability to regulate an HSC-enriched transcriptional program and potential to become leukemogenic upon chromosomal translocation in acute leukemia. We have shown using mouse loss- of-function models that Mll1 is essential for the development of HSCs during embryogenesis and for their maintenance in adult bone marrow. This role is carried out by maintaining expression of a network of transcriptional regulators including Hoxa9, Mecom/Evi1, Prdm16 and Meis1. Therefore we hypothesize that increasing MLL1 protein levels or activity could coordinately enhance this transcriptional network thereby enhancing HSC self-renewal and preventing differentiation. To test this hypothesis, we have created a new animal model that for the first time overcomes the resistance of many cell types to overexpress wild-type MLL1. Using single-copy integration into a doxycycline- inducible locus, we show increased hematopoietic output from embryoid bodies and embryo progenitors upon hMLL1 induction. In this Single Aim Shine II proposal, we seek to evaluate this animal model in detail to determine a) the developmental and differentiation stages that are permissive for hMLL1-induced hematopoietic expansion and b) identify regulatory networks that are altered by increased levels of MLL1 in relevant hematopoietic populations. It is our expectation that generating this proof-of-principle data linking increased MLL1 to enhanced hematopoiesis and determining the underlying mechanisms will guide future efforts to experimentally manipulate MLL1 in human stem and progenitor cells to expand their numbers and improve function in transplantation settings.

项目概要 为了维持持续的体内平衡，造血干细胞 (HSC) 拥有复杂的机制 平衡自我更新、增殖和分化。 HSC 发育期间和感染后 调整自我更新与差异化以扩大规模以满足但不超出市场的需求 生物。了解 HSC 如何调节这种平衡对于离体操作 HSC 至关重要 以改善移植中的使用。提高我们对平衡 HSC 自我更新与 其他需求，我们研究了与原癌基因 MLL1 相关的分子途径，因为它 调节富含 HSC 的转录程序的独特能力和成为 急性白血病中染色体易位导致白血病。我们已经展示了使用鼠标损失- 功能失调模型表明 Mll1 对于胚胎发生过程中 HSC 的发育至关重要 它们在成人骨髓中的维持。该作用是通过维持a的表达来实现的 转录调节子网络，包括 Hoxa9、Mecom/Evi1、Prdm16 和 Meis1。因此我们 假设增加 MLL1 蛋白水平或活性可以协调增强这种作用 转录网络从而增强HSC自我更新并防止分化。测试 根据这个假设，我们创建了一种新的动物模型，首次克服了耐药性 许多细胞类型过度表达野生型 MLL1。使用单拷贝整合到多西环素中- 诱导位点，我们显示拟胚体和胚胎的造血输出增加 hMLL1 诱导后的祖细胞。在这个 Single Aim Shine II 提案中，我们试图评估这一点 详细动物模型以确定 a) 的发育和分化阶段 b) 确定 hMLL1 诱导的造血扩张的调节网络 相关造血细胞群中 MLL1 水平升高而改变。我们的期望是 生成这一原理验证数据，将增加的 MLL1 与增强的造血功能联系起来， 确定潜在机制将指导未来实验性操纵 MLL1 的努力 人类干细胞和祖细胞在移植中扩大数量并改善功能 设置。