Regulation of Hematopoietic Progenitors by de novo DNA Methylation

DNA 从头甲基化对造血祖细胞的调节

• 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
• 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

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，可保护基因组免受传播突变的传播和调节基因表达。异常的DNA甲基化越来越多地被认为是在许多病理状态下发现的主要表观遗传扰动，并且在骨髓增生性综合征（MDS）的背景下已特别感兴趣。 MDS是一种失调的造血状态，其特征是增加贫血，并伴有高骨髓爆炸数。 MDS的发病率随着年龄的增长而增加，具有重大的病理影响，有时是急性髓样白血病（AML）的前体。异常DNA甲基化与MDS的相关性得到了有关MDS患者造血细胞的DNA甲基化谱的数据，以及促氮氨酸氨基氨酸和指定的临床价值，抑制DNA甲基化的临床价值，并且至少显示出一些临床效率。然而，DNA甲基化失调的机制以及DNA甲基化导致血液学障碍的扰动的方式是不透明的。在这里，我们将使用小鼠作为模型来研究当诱导DNA甲基转移酶特异性改变时发生的血液学功能的扰动。我们假设丧失适当的DNMT3A或DNMT3B表达会导致异常的DNA甲基化，从而改变了破坏自我更新和分化之间平衡的基因表达，最终导致了无能为力的干细胞种群，无法促进持续的血液形成。我们有两个广泛的目标，可以在功能和分子水平上探索这一点。我们将确定DNMT3S在调节鼠造血干细胞功能中的作用。我们将使用干细胞纯化和骨髓移植来诱导DNMT3基因的缺失，以检查HSC的分化和自我更新特性。我们将确定异常的DNMT3表达概括小鼠中MDS样疾病的程度。用DNA甲基化抑制剂对小鼠的处理将揭示对造血祖细胞的功能后果以及甲基化模式的变化。我们还将使用DNA甲基化分析来确定从头DNA甲基转移酶丧失的分子后果。这些变化将与伴随DNMT3A或DNMT3B的基因表达改变有关。我们还将研究有关其他全球表观遗传调节剂的结合的后果。这些研究将使我们能够确定HSC中DNMT3S的作用方式，并确定特定的基因，这些基因是赋予DNMT3删除HSC中改变表型的候选者。通过分析HSC中DNMT3损失的表型和功能后果，我们将提供第一个详细的DNMT3在任何成年细胞类型中的作用的详细肖像。这些数据将提供有关病理状态（尤其是MD的DNA甲基化改变）作用的见解。对DNA甲基化如何调节干细胞自我更新和分化以及鉴定介导该作用的关键基因的鉴定可能为未来的治疗性发育提供新的靶标。 公共卫生相关性：我们发现改变DNA结构（DNA甲基转移酶）的蛋白质可以帮助调节这些血液形成干细胞产生血液的能力。这些蛋白质通常因年龄失调，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产生可以改善骨髓移植并深入了解骨髓增生综合征的发展。