Thyroid hormone-dependent DNA methylation in the developing brain

发育中大脑中甲状腺激素依赖性 DNA 甲基化

• 批准号: 8462787
• 负责人: Yasuhiro Kyono
• 金额: $ 3.22万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-07-01 至 2013-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8462787
• 关键词: Amphibia; Binding; Biological Assay; Biological Metamorphosis; Biological Models; Brain; Cell Cycle; Cell Cycle Progression; Cell Cycle Regulation; Cell Differentiation process; Cell Line; Cell Lineage; Cell Proliferation; Cells; ChIP-seq; Comparative Genomic Analysis; Cretinism; Cyclin D1; DNA; DNA Methylation; DNA Methyltransferase; DNA Modification Methylases; DNMT3a; DNase-I Footprinting; Data Reporting; Defect; Development; Diagnosis; EMSA; Electroporation; Enhancers; Enzymes; Gene Expression; Gene Transfer; Genes; Goals; Growth; Human; Human Development; Introns; Lead; Literature; Mammals; Mediating; Mental Retardation; Messenger RNA; Methylation; Morphology; Mus; Neuroglia; Neurologic; Neuronal Differentiation; Neurons; Play; Prevention; Production; Protein Biosynthesis; Psyche structure; RXR; Rana; Regulation; Reporter; Repression; Research; Response Elements; Role; Schizophrenia; Tadpoles; Testing; Thyroid Hormone Receptor; Thyroid Hormones; Transactivation; Up-Regulation; Work; Xenopus; autism spectrum disorder; base; critical period; hormone deficiency; hormone response element; in vivo; migration; mouse genome; nerve stem cell; neuroblastoma cell; neurogenesis; overexpression; postnatal; promoter; receptor; subventricular zone

DESCRIPTION (provided by applicant): Postembryonic brain development is dependent on thyroid hormone (TH). Thyroid hormone deficiency during critical periods of human development leads to a condition of severe mental and growth retardation known as cretinism. Thyroid hormone has pleiotropic actions in the developing brain, including regulating cell proliferation, cell cycle exit and differentiation (neurogenesis). The goal of this research is to investigate the mechanisms by which TH promotes cell cycle exit and neurogenesis through its regulation of the de novo DNA methyltransferase DNMT3a. Amphibian development (metamorphosis) is dependent on TH, and we propose to use Xenopus tadpoles for our studies. We found that expression of the dnmt3a gene is strongly upregulated in subventricular zones (neurogenic zones) of the tadpole brain during spontaneous metamorphosis, or following treatment with TH. The frog dnmt3a gene has a putative TH response element (TRE) located in the intron, supporting direct TH receptor (TR) regulation. Comparative genomic analysis identified a similar, putative TRE in the mouse genome, supporting evolutionarily conservation of dnmt3a regulation by TR. Furthermore, TH induced dnmt3a mRNA in the mouse neuroblastoma cell line N2a[TR21]. Thyroid hormone is essential for neurogenesis during the early postnatal period. Recent findings showed that dnmt3a is required for neurogenesis. Gene expression analysis of neural stem cells (NSCs) from dnmt3a- deficient mice showed upregulation of genes involved in cell cycle control, supporting a defect in cell cycle exit and differentiation into the neuronal lineage. Several lines of evidence support that cyclin D1 is directly regulated by DNMT3a-mediated DNA methylation. Based on our preliminary findings and data reported in the scientific literature, we hypothesize that TH influences cell cycle exit in neural stem cells and neurogenesis through induction of Dnmt3a. To test this hypothesis we will investigate: 1) the functionality of the evolutionarily conserved TREs in frog and mouse dnmt3a genes; 2) a role for DNMT3a in repression of cyclin D1 through methylation of its promoter; and 3) the effects of altering DNMT3a expression in vivo on cell cycle exit and lineage specification of NSCs. Successful completion of the proposed research will lead to advances in our understanding of the mechanisms by which TH controls neurological development through its influence on DNA methylation. Such understanding can contribute to the prevention, diagnosis and treatment of human neurological conditions such as mental retardation, autism spectrum disorder and schizophrenia.

描述（由申请人提供）：胚胎后脑发育取决于甲状腺激素（Th）。在人类发展的关键时期，甲状腺激素缺乏症会导致一种严重的精神和生长迟缓的疾病，称为葡萄抗激素。甲状腺激素在发育中的大脑中具有多效性作用，包括调节细胞增殖，细胞周期出口和分化（神经发生）。这项研究的目的是研究通过调节从头DNA甲基转移酶DNMT3A来促进细胞周期出口和神经发生的机制。两栖动物发育（变形）取决于Th，我们建议使用爪蟾t骨进行研究。我们发现，DNMT3A基因的表达在自发变质过程中t骨的室室（神经源性区）中强烈上调，或者在用Th进行治疗后。青蛙DNMT3A基因具有内含子中的推定的TH响应元件（TRE），支持直接TH受体（TR）调节。比较基因组分析确定了小鼠基因组中类似的推定TRE，从而支持了TR的进化保护DNMT3A调节。此外，Th在小鼠神经母细胞瘤细胞系N2A中诱导DNMT3A mRNA [TR21]。甲状腺激素在产后早期对神经发生至关重要。最近的发现表明，DNMT3A是神经发生所必需的。来自DNMT3A缺陷小鼠的神经干细胞（NSC）的基因表达分析表现出参与细胞周期控制的基因上调，支持细胞周期出口的缺陷并分化为神经元谱系。几条证据支持Cyclin D1受DNMT3A介导的DNA甲基化直接调节。基于我们在科学文献中报道的初步发现和数据，我们假设，通过诱导DNMT3A，TH会影响神经干细胞的细胞周期出口和神经发生。为了检验该假设，我们将研究：1）在青蛙和小鼠DNMT3A基因中进化保守的TRE的功能； 2）DNMT3A通过其启动子的甲基化抑制细胞周期蛋白D1的作用； 3）改变体内DNMT3A表达对NSC的细胞周期出口和谱系规范的影响。成功完成拟议的研究将导致我们了解神经系统对DNA甲基化控制神经系统发育的机制的进步。这种理解可以有助于预防，诊断和治疗人类神经系统疾病，例如智力低下，自闭症谱系障碍和精神分裂症。

项目成果

DNA methylation dynamics underlie metamorphic gene regulation programs in Xenopus tadpole brain.

• DOI: 10.1016/j.ydbio.2020.03.013
• 发表时间: 2020-03
• 期刊: Developmental biology
• 影响因子: 2.7
• 作者: Yasuhiro Kyono;Samhitha Raj;Christopher J. Sifuentes;N. Buisine;L. Sachs;R. Denver