Regulation of Hematopoietic Progenitors by de novo DNA Methylation

DNA 从头甲基化对造血祖细胞的调节

基本信息

批准号：
8371066
负责人：
MARGARET A. GOODELL
金额：
$ 38.96万
依托单位：
BAYLOR COLLEGE OF MEDICINE
依托单位国家：
美国
项目类别：
财政年份：
2012
资助国家：
美国
起止时间：
2012-08-01 至 2016-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8371066
关键词：
Aberrant DNA Methylation Ablation Acute Myelocytic Leukemia Adult Age Age-Months Anemia Azacitidine Binding Blast Cell Blood Bone Marrow Transplantation Candidate Disease Gene Cell physiology Cells Clinical DNA DNA Methylation DNA Methyltransferase DNA Modification Methylases DNA Structure Data Development Disease Dysmyelopoietic Syndromes Enzymes Epigenetic Process Equilibrium Frequencies Future Gene Expression Genes Genome Goals Hematopoiesis Hematopoietic Hematopoietic stem cells Hypermethylation Impotence Incidence Individual Lead Life Link Marrow Mediating Methylation Modeling Modification Molecular Mus Mutation Nucleic Acid Regulatory Sequences Pathologic Patients Pattern Phenotype Portraits Process Production Property Proteins Regulation Role Stem cells Work cell type clinical efficacy improved inhibitor/antagonist insight interest mutant progenitor self-renewal stem cell population therapeutic development

项目摘要

DESCRIPTION (provided by applicant): DNA methylation is an important epigenetic modification that serves to protect the genome from propagating mutations, and to regulate gene expression. Aberrant DNA methylation is increasingly being recognized as a major epigenetic perturbation found in many pathologic states, and has become of particular interest in the context of myelodysplastic syndrome (MDS). MDS is a state of dysregulated hematopoiesis that is characterized by increasing anemia accompanied by high marrow blast counts. MDS incidence increases with age, has substantial pathologic impact, and is sometimes a precursor to acute myeloid leukemia (AML). The relevance of aberrant DNA methylation to MDS has been supported by data on the DNA methylation profiles on hematopoietic cells from MDS patients, as well the clinical value of azacytidine and decitibine, treatments that inhibit DNA methylation and have shown at least some clinical efficacy. However, the mechanisms of DNA methylation dysregulation, as well as the manner in which perturbations of DNA methylation lead to hematologic disturbance, are opaque. Here, we will use mice as a model to study the perturbations of hematologic function that occur when specific alterations in DNA methyltransferases are induced. We hypothesize that loss of appropriate Dnmt3a or Dnmt3b expression leads to aberrant DNA methylation, altering the expression of genes that disrupt the balance between self-renewal and differentiation, ultimately leading to an impotent stem cell population unable to contribute to ongoing blood formation. We have two broad aims to explore this at functional and at molecular levels. We will determine the roles of Dnmt3s in regulation of murine hematopoietic stem cell function. We will induce deletion of the Dnmt3 genes to examine the differentiation and self-renewal properties of HSC, using stem cell purification and bone marrow transplantation. We will determine the extent to which aberrant Dnmt3 expression recapitulates an MDS-like disease in mice. Treatment of mice with DNA methylation inhibitors will reveal the functional consequences on hematopoietic progenitors and the resulting changes in methylation patterns. We will also determine the molecular consequences of loss of de novo DNA methyltransferases using global analysis of DNA methylation. These changes will be correlated with alterations in gene expression that accompany loss of Dnmt3a or Dnmt3b. We will also examine the consequences with regard to binding of additional global epigenetic regulators. These studies will allow us to determine the mode of action of the Dnmt3s in HSC, as well as to identify specific genes that are candidates for conferring the altered phenotype in Dnmt3-deleted HSCs. By analyzing the phenotypic and functional consequences of Dnmt3 loss in HSCs, we will provide the first detailed portrait of the role of Dnmt3s in any adult cell type. These data will offer insights into the role of DNA methylation alterations in pathologic states, particularly MDS. A deeper understanding of how DNA methylation regulates stem cell self-renewal and differentiation, and identification of the key genes that mediate the effects, may offer new targets for future therapeutic development. PUBLIC HEALTH RELEVANCE: We have found that proteins, which alter the structure of DNA (DNA methyltransferases) can help regulate the ability of these blood forming stem cells to make blood. These proteins are often dysregulated with age, correlating with the dysregulated blood production. Understanding how these proteins regulate stem cells and blood production may improve bone marrow transplantation and lend insight into development of myelodysplastic syndromes.

描述（由申请人提供）：DNA甲基化是一种重要的表观遗传修饰，用于保护基因组免于传播突变并调节基因表达。异常 DNA 甲基化越来越被认为是许多病理状态中发现的主要表观遗传扰动，并且在骨髓增生异常综合征 (MDS) 的背景下受到特别关注。 MDS 是一种造血失调状态，其特征是贫血加剧并伴有高骨髓母细胞计数。 MDS 发病率随着年龄的增长而增加，具有显着的病理影响，有时是急性髓系白血病 (AML) 的先兆。异常 DNA 甲基化与 MDS 的相关性已得到 MDS 患者造血细胞 DNA 甲基化谱数据的支持，以及氮胞苷和地西替滨（抑制 DNA 甲基化的治疗方法并至少显示出一些临床疗效）的临床价值。然而，DNA 甲基化失调的机制以及 DNA 甲基化扰动导致血液学紊乱的方式尚不清楚。在这里，我们将使用小鼠作为模型来研究当 DNA 甲基转移酶的特定改变被诱导时发生的血液功能的扰动。我们假设，适当的 Dnmt3a 或 Dnmt3b 表达缺失会导致异常的 DNA 甲基化，改变基因的表达，从而破坏自我更新和分化之间的平衡，最终导致干细胞群体无能，无法参与持续的血液形成。我们有两个广泛的目标在功能和分子水平上探索这一点。我们将确定 Dnmt3 在调节小鼠造血干细胞功能中的作用。我们将利用干细胞纯化和骨髓移植诱导 Dnmt3 基因缺失，以检查 HSC 的分化和自我更新特性。我们将确定异常 Dnmt3 表达在多大程度上重现小鼠中的 MDS 样疾病。用 DNA 甲基化抑制剂治疗小鼠将揭示其对造血祖细胞的功能影响以及由此产生的甲基化模式的变化。我们还将利用 DNA 甲基化的整体分析来确定 DNA 从头甲基转移酶丢失的分子后果。这些变化将与伴随 Dnmt3a 或 Dnmt3b 缺失而发生的基因表达变化相关。我们还将研究与其他全球表观遗传调节因子结合的后果。这些研究将使我们能够确定 Dnmt3 在 HSC 中的作用模式，并确定在 Dnmt3 缺失的 HSC 中赋予改变表型的候选基因。通过分析 HSC 中 Dnmt3 缺失的表型和功能后果，我们将首次详细描述 Dnmt3 在任何成体细胞类型中的作用。这些数据将深入了解 DNA 甲基化改变在病理状态（尤其是 MDS）中的作用。更深入地了解 DNA 甲基化如何调节干细胞自我更新和分化，并鉴定介导这种影响的关键基因，可能为未来的治疗开发提供新的目标。公共健康相关性：我们发现改变 DNA 结构的蛋白质（DNA 甲基转移酶）可以帮助调节这些造血干细胞制造血液的能力。这些蛋白质通常随着年龄的增长而失调，与血液产生失调相关。了解这些蛋白质如何调节干细胞和血液生成可能会改善骨髓移植并有助于深入了解骨髓增生异常综合征的发展。