5-Hydroxymethylcytosine and Globin Gene Switching

5-羟甲基胞嘧啶和珠蛋白基因转换

基本信息

批准号：
8677966
负责人：
DONALD LAVELLE
金额：
$ 39.08万
依托单位：
UNIVERSITY OF ILLINOIS AT CHICAGO
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：
2012-08-15 至 2016-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8677966
关键词：
Adult Agonist Bone Marrow CD34 gene Cell Culture Techniques Cells Chemicals Chromosomes, Artificial, Yeast Clinical Trials DNA DNA Methylation DNA Methyltransferase Inhibitor Data Development Dimerization Dioxygenases Effectiveness Enzyme Inhibitor Drugs Erythroid Cells Erythropoiesis Eukaryotic Cell Family Fetal Hemoglobin Fetal Liver Fostering Future Gene Expression Genes Globin Goals Hemoglobin concentration result Human Knock-in Mouse Knowledge Laboratories Lead Longevity Mediating Modeling Modification Molecular Mus Papio Pathway interactions Patients Pattern Pharmaceutical Preparations Physiological Play Pregnancy Principal Investigator Quality of life RNA Interference Regulation Role Series Severities Sickle Cell Anemia Staging Switch Genes Symptoms System Testing Thalassemia Time Transgenic Mice Umbilical Cord Blood Validation beta Thalassemia demethylation design erythroid differentiation fetal gamma Globin mouse model novel programs promoter research study therapy development

项目摘要

DESCRIPTION (provided by applicant): Increased fetal hemoglobin (HbF) levels lessen the severity of symptoms associated with sickle cell disease and beta-thalassemia and increase the quality of life and life span of patients. A complete understanding of the mechanism(s) responsible for developmental regulation of globin gene expression (globin gene switching) is important to develop new therapies to increase HbF. Over 30 years of experimental evidence from multiple laboratories strongly supports the hypothesis that DNA methylation plays a fundamental role in silencing expression of the gamma-globin gene in the adults. The use of pharmacological inhibitors of DNA methyltransferase to increase HbF levels was pioneered in the baboon model in our laboratory and led to a series of clinical trials that demonstrated the effectiveness of these drugs in patients. Using the baboon model, our laboratory also made the novel and important observation showing that the gamma-globin gene promoter was demethylated in a progressive manner during fetal liver erythropoiesis. The mechanism responsible for DNA demethylation of the gamma-globin promoter during fetal liver erythropoiesis remains unknown. Our preliminary data shows that increased levels of 5-hydroxymethylcytosine (5-hmC), a novel modification of 5-methylcytosine (5-mC) recently found in eukaryotic cells that is catalyzed by the TET dioxygenase family, are associated with the gamma-globin promoter in erythroid cells expressing elevated levels of gamma-globin. 5-hmC has been proposed to be a key intermediate in both passive and active mechanisms of DNA demethylation and therefore our preliminary data strongly suggests that 5-hmC is involved in the mechanism responsible for demethylation of the gamma-globin gene during fetal liver erythropoiesis. This proposal will investigate the hypothesis that DNA demethylation of the gamma-globin gene during fetal erythroid differentiation is accomplished through a TET- mediated pathway involving 5-hmC. Validation of this hypothesis will define a crucial mechanism (s) in normal developmental fetal stage-specific activation of gamma-globin expression. We envision that detailed knowledge of the normal, physiological mechanism responsible for gamma-globin gene demethylation during fetal liver erythropoiesis will foster the development of new strategies targeting this mechanism to achieve DNA demethylation and high level activation of the gamma-globin gene to increase HbF in patients.

描述（由申请人提供）：胎儿血红蛋白（HbF）水平的增加可减轻与镰状细胞病和β-地中海贫血相关的症状的严重程度，并提高患者的生活质量和寿命。完整了解珠蛋白基因表达发育调节（珠蛋白基因转换）的机制对于开发增加 HbF 的新疗法非常重要。来自多个实验室 30 多年的实验证据有力地支持了这样的假设：DNA 甲基化在抑制成人中 γ-珠蛋白基因的表达方面发挥着重要作用。我们实验室在狒狒模型中率先使用 DNA 甲基转移酶药物抑制剂来提高 HbF 水平，并进行了一系列临床试验，证明了这些药物对患者的有效性。利用狒狒模型，我们实验室还进行了新颖而重要的观察，表明在胎儿肝脏红细胞生成过程中，γ-珠蛋白基因启动子逐渐去甲基化。胎儿肝脏红细胞生成过程中伽马珠蛋白启动子 DNA 去甲基化的机制仍不清楚。我们的初步数据表明，5-羟甲基胞嘧啶 (5-hmC) 水平的增加与 γ-珠蛋白有关，5-羟甲基胞嘧啶 (5-hmC) 是最近在真核细胞中发现的 5-甲基胞嘧啶 (5-mC) 的一种新修饰，由 TET 双加氧酶家族催化。红系细胞中表达升高水平的γ-珠蛋白的启动子。 5-hmC 被认为是 DNA 去甲基化的被动和主动机制中的关键中间体，因此我们的初步数据强烈表明，5-hmC 参与了胎儿肝红细胞生成过程中γ-珠蛋白基因去甲基化的机制。该提案将研究以下假设：胎儿红系分化过程中 γ-珠蛋白基因的 DNA 去甲基化是通过涉及 5-hmC 的 TET 介导途径完成的。该假设的验证将定义正常发育胎儿阶段特异性伽马珠蛋白表达激活的关键机制。我们设想，对胎儿肝脏红细胞生成过程中γ-珠蛋白基因去甲基化的正常生理机制的详细了解将促进针对该机制的新策略的开发，以实现DNA去甲基化和γ-珠蛋白基因的高水平激活，从而增加胎儿肝脏中的HbF。患者。