The Role of Dot1L in developing and postnatal heart

Dot1L 在发育和产后心脏中的作用

基本信息

批准号：
8750576
负责人：
SYLVIA M EVANS
金额：
$ 38.75万
依托单位：
UNIVERSITY OF CALIFORNIA, SAN DIEGO
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：
2014-08-01 至 2018-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8750576
关键词：
Ablation Accounting Address Adult Adverse effects Apoptosis Blood Vessels Cardiac Cardiac Myocytes Cardiomegaly Cardiomyopathies Cardiovascular Abnormalities Cell Cycle Cell Cycle Regulation Cell Nucleus Cell Size ChIP-seq Chromatin Chromatin Remodeling Factor Data Data Analyses Defect Development Dilated Cardiomyopathy Docking Dystrophin Embryo Enzymes Epigenetic Process Exhibits Future Gene Expression Gene Expression Regulation Genes Genetic Transcription Goals Health Heart Heart Diseases Histone Acetylation Histone H3 Histones Hyperplasia In Vitro Injury Intercalated disc Length Lysine Mediating Methylation Methyltransferase Modification Morphology Mus Muscle Cells Neonatal Pathway interactions Perinatal Phenotype Play Ploidies Pregnancy Proliferating Proteins RNA Splicing Regulation Role Secondary to Staging Structure Testing Therapeutic Time Tissues Transcriptional Regulation Work cardiac regeneration cardiac repair cardiogenesis cdc Genes cofactor congenital heart disorder embryonic stem cell genome-wide heart function histone modification in vivo inhibitor/antagonist insight interest leukemia mutant new therapeutic target postnatal programs regenerative therapy research study telomere therapy development transcription factor transcriptome sequencing

项目摘要

DESCRIPTION (provided by applicant): Regulation of gene transcription is key to understanding mechanisms underlying heart development, congenital heart disease, and developing therapies for heart regeneration post injury. Epigenetic modifications are key modulators of the transcriptional landscape, and as such, enzymes which catalyze these modifications have become a subject of great interest. In particular, histone modifications are thought to play key roles in multiple aspects of gene regulation, including mediating interactions with chromatin remodeling factors, docking of general or specific tissue specific transcription factors or cofactors, and perhaps mediating splicing. Histone acetylation and deacteylation have been intensely studied. More recently, histone methylation has come under scrutiny, and greater understanding of the role of specific methylation marks has emerged. The histone methylation mark histone H3 lysine 79 (H3K79), is uniquely catalyzed by the lysine methyltransferase, DOT1L. Multiple lines of evidence suggest critical and specific roles for DOT1L during cardiogenesis and in postnatal heart. DOT1L is highly expressed in the heart throughout development, and global ablation of Dot1L results in mid-gestation lethality with multiple cardiovascular abnormalities. Ablation of Dot1L in cardiomyocytes at mid-gestation with αMHC-cre results in cardiomyopathy in adult heart, accounted for in part by perturbation of dystrophin gene expression. Evidence from cardiomyocyte differentiation of mouse embryonic stem cells indicated that DOT1L plays a critical role at earliest stages of cardiomyocyte differentiation, yet no in vivo studies have addressed this issue. Accordingly, in preliminary studies, we have ablated Dot1L at E7.5 utilizing xMLCcre, and found that mutants exhibited cardiomyocyte hyperplasia, dying in the early postnatal period. Preliminary studies ablating Dot1L in perinatal mouse cardiomyocyte cultures demonstrated an ongoing requirement for Dot1L to regulate cardiomyocyte cell cycle. Preliminary studies have demonstrated enrichment of H3K79 methyl marks at cardiac gene loci in neonatal and adult myocytes. Together, these observations have led to our hypothesis that Dot1L is required in cardiomyocytes at embryonic, neonatal and adult stages for cardiomyocyte cell cycle regulation and progressive differentiation of cardiomyocytes. To test this hypothesis, our Specific Aims are: 1) To characterize the cardiac phenotype of early cardiomyocyte-specific Dot1L mutants. 2) To identify genes directly regulated, positively or negatively, by DOT1L mediated-H3K79 methylation in vivo. 3) To examine the requirement for Dot1L in postnatal and adult heart. Results of these studies will give mechanistic insight into the role of DOT1L in cardiomyocytes throughout distinct developmental stages and in postnatal and adult heart. Importantly, these studies promise to give insights into mechanisms by which epigenetic modifications regulate cardiomyocyte cell cycle, and are therefore likely to suggest therapeutic approaches for cardiac repair in both developing and adult heart. DOT1L inhibitors are currently being tested for treatment of MLL-associated leukemias, therefore our studies will be informative as to potential cardiac side effects of these inhibitors. Our studies will also address the future potential of DOT1L inhibitors for cardiac regenerative therapies.

描述（通过应用提供）：基因转录的调节是理解心脏发育，先天性心脏病和开发损伤后心脏再生疗法的机制的关键。表观遗传修饰是转录景观的关键调节剂，因此，催化这些修饰的酶已成为引起人们极大兴趣的主题。特别是，人们认为组蛋白修饰在基因调节的多个方面起着关键作用，包括介导与染色质重塑因子的相互作用，对接一般或特定组织特异性转录因子或辅助因子或辅助因子以及可能介导的剪接。组蛋白乙酰化和脱氧化已被积极研究。最近，组蛋白甲基化受到了审查，对特定甲基化标记的作用有了更大的了解。组蛋白甲基化标记组蛋白H3赖氨酸79（H3K79），由赖氨酸甲基转移酶DOT1L唯一催化。多种证据表明心脏发生和产后心脏中DOT1L的关键和特定作用。在整个发育过程中，DOT1L在心脏中都高度表达，而DOT1L的全球消融导致妊娠中期的致死性，并具有多种心血管异常。在妊娠中期与αMHC-CRE的心肌细胞中DOT1L在成年心脏中导致心肌病，部分原因是肌营养不良蛋白基因表达的部分原因。小鼠胚胎干细胞的心肌细胞分化的证据表明，在心肌细胞分化的最早阶段，DOT1L起着至关重要的作用，但是体内研究没有解决这个问题。根据初步研究，我们使用XMLCCRE的E7.5消融了DOT1L，发现突变体暴露了心肌细胞增生，在产后早期死亡。初步研究在围产期小鼠心肌细胞培养物中的燃料DOT1L表明，DOT1L调节心肌细胞周期的持续要求。初步研究表明，在新生儿和成年肌细胞中，心脏基因基因座的H3K79甲基标记富集。总之，这些观察结果导致了我们的假设，即在胚胎，新生儿和成人阶段的心肌细胞中需要DOT1L，以进行心肌细胞周期调节以及心肌细胞的进行性分化。为了检验这一假设，我们的具体目的是：1）表征早期心肌细胞特异性DOT1L突变体的心脏表型。 2）在体内介导的-H3K79甲基化直接鉴定基因，正面或负面调节。 3）检查产后和成人心脏中DOT1L的要求。这些研究的结果将使机械洞察力洞察DOT1L在不同的发育阶段以及产后和成人心脏中的心肌细胞中的作用。重要的是，这些研究有望深入了解表观遗传修饰调节心肌细胞周期的机制，因此很可能提出了发育中和成人心脏中心脏修复的治疗方法。目前正在对DOT1L抑制剂进行测试以治疗与MLL相关的白血病，因此我们的研究将为这些抑制剂的潜在心脏副作用提供信息。我们的研究还将解决DOT1L抑制剂的未来潜力用于心脏再生疗法。