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: 9814577
• 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/9814577
• 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; Stem cells; 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 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 cell differentiation; 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.

项目摘要 为了维持持续的稳态，造血干细胞（HSC）具有精致的机制 平衡自我更新，增殖和分化。在发育期间和感染后HSC之后 调整自我更新与差异化以扩展到满足但不超出需求 生物。了解HSC如何调节这种平衡对于操纵HSC的ex Vivo至关重要 用于改善移植的使用。为了提高我们的理解，平衡HSC自我更新与 其他需求，我们研究了与原始癌基因MLL1相关的分子途径 调节富含HSC的转录程序的独特能力，并有潜力 急性白血病中染色体易位的白血病。我们已经表明使用小鼠损失 - MLL1的功能模型对于在胚胎发生过程中的HSC发展至关重要 它们在成年骨髓中的维护。通过保持表达来执行此角色 转录调节器的网络包括Hoxa9，Mecom/EVI1，PRDM16和MEIS1。因此我们 假设增加MLL1蛋白水平或活性可能会协调一致 转录网络，从而增强HSC自我更新并防止分化。测试 这个假设，我们创建了一个新的动物模型，该模型首次克服了阻力 在许多过表达野生型MLL1的细胞类型中。将单拷贝整合到多西环素中 诱导型基因座，我们显示出胚胎和胚胎的造血输出增加 HMLL1诱导后的祖细胞。在这个单一目标Shine II提案中，我们试图评估这一点 详细的动物模型以确定a）发展和分化阶段 允许HMLL1诱导的造血扩张和b）确定调节网络 在相关造血人群中MLL1水平的增加而改变。我们的期望是 生成这种原则数据链接的原则证明将MLL1与增强的造血和 确定基本机制将指导未来的努力，以实验操纵MLL1 人类的茎和祖细胞扩大其数量并提高移植功能 设置。