Epigenetic and Cell Cycle Functions of Glucocorticoids in Erythropoietic Stress

糖皮质激素在红细胞生成应激中的表观遗传和细胞周期功能

基本信息

批准号：
9064125
负责人：
Merav Socolovsky
金额：
$ 36.18万
依托单位：
UNIV OF MASSACHUSETTS MED SCH WORCESTER
依托单位国家：
美国
项目类别：
财政年份：
2014
资助国家：
美国
起止时间：
2014-09-01 至 2019-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9064125
关键词：
Acceleration Adult Adverse effects Affect Anemia Antibodies Binding Blood Bone Density Bone Marrow Bone Marrow Transplantation CFU-E Cardiovascular Diseases Cell Cycle Cells Clinic Clinical Cyclin-Dependent Kinase Inhibitor DNA DNA Methylation DNA Modification Methylases DNA biosynthesis DNA replication fork Data Development Diabetes Mellitus Diamond-Blackfan anemia Down-Regulation Dysmyelopoietic Syndromes Epigenetic Process Erythrocyte Transfusion Erythrocytes Erythroid Erythropoiesis Erythropoietin Fiber Generations Genes Genetic Genetic Transcription Glucocorticoid Receptor Glucocorticoids Health Hemorrhage Hormonal Hormones Hypoxia In Vitro Laboratories Malignant Neoplasms Mediating Mediator of activation protein Modification Molecular Mus Mutate Mutation Oxygen Pharmaceutical Preparations Process Production Publishing Recovery Refractory Refractory anemias Relapse Replication Origin Resistance Risk Role S Phase SWI1 Science Signal Transduction Somatic Cell Stress Syndrome System TFRC gene Testing Tissues Transcriptional Activation Transferase Up-Regulation Work base biological adaptation to stress bone marrow failure syndrome chemotherapy demethylation fetal gene induction genome-wide human disease improved in vivo mouse model mutant novel overexpression prevent progenitor promoter receptor respiratory response self-renewal tumor

项目摘要

DESCRIPTION (provided by applicant): Glucocorticoids (GCs) are hormonal regulators of stress. They accelerate red blood cell production rate, an effect that is well established by mouse genetics, by in vitro erythropoiesis systems, and by human disease syndromes in which GCs are dysregulated. The use of GCs in the treatment of anemia is complicated, however, by their severe side effects, and is therefore limited to conditions where Erythropoietin (Epo) treatment is refractory or contraindicated, including Diamond Blackfan Anemia and other bone-marrow failure syndromes. The translational importance of GCs is apparent from their use in systems currently under development for the in-vitro generation of red blood cells for transfusion. Understanding the molecular action of GCs in erythroid progenitors could facilitate the development of novel erythropoiesis-stimulating agents that have fewer side-effects than GCs, and that improve the efficiency of generating red blood cells in vitro. Functionally, GCs increase erythropoietic rate by delaying the switch from self-renewal to differentiation in erythroid progenitors. The molecular mechanisms underlying this action are largely unknown. Based on our recently published work and on preliminary data, we propose a novel hypothesis of GC action that implicates the cell cycle S phase and DNA methylation as novel regulatory targets. We recently showed that both fetal and adult erythropoiesis entail genome-wide DNA demethylation, a unique global epigenetic modification in somatic cells (Shearstone et al., Science 2011). Global demethylation is tightly correlated with demethylation at erythroid gene promoters, and is a rate-limiting for their transcriptional activation. Further, global demethylatin is dependent on a marked change in S phase of the cell cycle, which becomes shorter and 50% faster with the switch from self-renewal to differentiation. The cyclin-dependent kinase inhibitor (CDKI) p57KIP2 is a key negative regulator of this switch. p57KIP2 is also a direct transcriptional target of GCs. Our preliminary data show that, in the presence of GCs, erythroid progenitors fail to downregulate p57KIP2, fail to accelerate S phase, and fail to undergo DNA demethylation, thereby delaying erythroid gene transcription. In this proposal, we investigate the hypothesis that high levels of GCs during erythropoietic stress inhibit the switch from self-renewal to differentiation by inducing p57KIP2, thereby inhibiting S phase acceleration, global DNA demethylation and erythroid gene induction. We will test this hypothesis in vivo using mouse models of erythropoietic stress and mice deleted or mutated for either p57KIP2, the GC receptor, or DNA methyl transferase 1 (Dnmt1), with the following three aims: 1) Determine the role of p57KIP2 in the GC-mediated erythropoietic stress response 2) Determine whether GCs prolong S phase in erythroid progenitors during stress 3) Determine whether GCs delay the onset of global DNA demethylation during stress. This work focuses on a unique epigenetic modification and has the potential to identify conceptually novel regulatory mechanisms, with translational implications for therapy of Epo-resistant anemia.

描述（由申请人提供）：糖皮质激素（GC）是压力的激素调节剂。它们加速了红细胞的产生率，这种作用是由小鼠遗传学，体外红细胞生成系统和人类疾病综合征良好确定的，其中GC被失调。然而，通过严重的副作用，GC在贫血治疗中的使用是复杂的，因此仅限于促红细胞生成素（EPO）治疗是难治性或禁忌症的条件，包括钻石黑芬贫血和其他骨髓衰竭综合症。 GCS的翻译重要性是从当前正在开发的系统中用于输血的红细胞内产生的系统的重要性。了解GC在红细胞祖细胞中的分子作用可以促进与GC相比副作用少的新型红细胞生成剂的发展，从而提高了体外产生红细胞的效率。从功能上讲，GC通过延迟从自我更新到红细胞祖细胞分化的转换来提高红细胞生成率。该作用的基本分子机制在很大程度上是未知的。基于我们最近发表的工作和初步数据，我们提出了一个新的GC作用假设，该假设将细胞周期的相位和DNA甲基化作为新的调节靶标。我们最近表明，胎儿和成人红细胞生成都需要全基因组DNA脱甲基化，这是体细胞中独特的全球表观遗传修饰（Shearstone等，Science 2011）。在红细胞基因启动子处，全局脱甲基与脱甲基紧密相关，并且是其转录激活的速率限制。此外，全球脱甲基蛋白取决于细胞周期的S相的显着变化，随着从自我更新转变为分化，该甲基蛋白的变化速度较短和50％。依赖细胞周期蛋白的激酶抑制剂（CDKI）P57KIP2是该开关的关键负调节剂。 P57KIP2也是GC的直接转录靶标。我们的初步数据表明，在GC存在的情况下，红细胞祖细胞未能下调p57KIP2，无法加速S相，并且无法进行DNA脱甲基化，从而延迟了红细胞基因转录。在该提案中，我们研究了以下假设：促红细胞性压力期间的高水平的GCS通过诱导p57KIP2抑制从自我更新到分化的转变，从而抑制了S相加速，全球DNA脱甲基化和诱导促进基因。我们将使用p57KIP2，GC受体或DNA甲基转移酶1（DNMT1）的偶然应激的小鼠模型（DNMT1）在体内检验该假设，并突变为以下三个目的：1），确定P57KIP2在GC介导的eRythropo Erythropo Enser中的作用。压力期间的祖细胞3）确定GC是否在应力期间是否会延迟全局DNA脱甲基化的发作。这项工作着重于独特的表观遗传修饰，并具有识别概念上新颖的调节机制的潜力，对抗epo-耐药性贫血的治疗具有翻译意义。