Genetic and epigenetic contributions to the neonatal Th2 bias

遗传和表观遗传对新生儿 Th2 偏向的贡献

基本信息

批准号：
8424735
负责人：
REBECCA D ADKINS
金额：
$ 23.01万
依托单位：
UNIVERSITY OF MIAMI SCHOOL OF MEDICINE
依托单位国家：
美国
项目类别：
财政年份：
2013
资助国家：
美国
起止时间：
2013-04-10 至 2015-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8424735
关键词：
Adult Allergic Disease Allogeneic Lymphocyte Anti-Inflammatory Agents Anti-inflammatory Asthma Birth CD4 Positive T Lymphocytes Catalytic Domain Cell Lineage Cells Childhood Chromatin Coupled Cytokine Gene DNA DNA Methyltransferase DNA Modification Methylases DNA-Binding Proteins Data Development Developmental Biology Disease Effector Cell Elements Employee Strikes Enhancers Epigenetic Process Exposure to Foundations Functional RNA Future Gene Expression Genes Genetic Genome Genome Components Goals Growth Health Immune response Immune system Immunity In Vitro Infection Interleukin-13 Interleukin-4 Intervention Knowledge Lead Learning Life Link Mediating Memory Methylation Methyltransferase Modification Molecular Monitor Mus Neonatal Newborn Animals Nucleic Acid Regulatory Sequences Pattern Play Predisposition Prevention approach Production Proteins Regulation Regulatory Element Resistance Role Staging T-Lymphocyte Techniques Testing Th2 Cells Transgenic Mice Vaccination Vaccines Work Zinc Fingers base cytokine demethylation design fetal genetic element genetic manipulation improved in vivo juvenile animal meetings microorganism neonate novel novel strategies prevent public health relevance research study response

项目摘要

DESCRIPTION (provided by applicant): Immune responses in neonates are often defined by dominant production of anti-inflammatory Th2 cytokines, a condition referred to as the neonatal Th2 bias. This pattern of cytokine secretion is thought to contribute to the susceptibility of young animals to infection and to the development of Th2-mediated diseases, such as asthma. Thus, vigorous Th2 function is a key defining feature of immunity in early life. Learning how this arises is of central importance for our understanding of the ontogeny of the adaptive immune system. The Th2 biased responses of neonates are due, in part, to rapid, high-level Th2 cytokine production. We have demonstrated that the Th2 cytokines IL-4 and IL-13 are both produced early and in copious amounts by newly activated murine neonatal CD4+ cells. In adult Th2 cells, coordinate expression of high levels of Th2 cytokines requires an intergenic regulatory region called conserved non-coding region 1 (CNS-1). Therefore, the CNS-1 genetic element may contribute importantly to the early, robust Th2 cytokine production in neonates. Indeed, this DNA element exists in a relatively permissive epigenetic state in early ontogeny. We have found that, unlike in naive adult cells, CNS-1 is hypomethylated at CpG residues in naive fetal and neonatal T lineage cells. This hypomethylated state is strongly linked to rapid, high level Th2 cytokine production by neonatal CD4+ cells. Methylation of CNS-1 occurs rapidly post birth, with adult levels of methylation being attained by the end of the first week o life. Increasing methylation of CNS-1 with increasing development is associated with the progressive silencing of rapid Th2 cytokine gene expression. Together, these observations indicate that CNS-1 may play a centrally important role in defining the neonatal Th2 bias. Our long-term goals are to understand the genetic and epigenetic contributions to the Th2 dominant state of early life. In this proposal, we will focus on the well-defined CNS-1 region in the Th2 cytokine locus. Our preliminary data lead to two clear hypotheses. Specific Aim 1 will test the idea that the physical presence of the CNS-1 region is required to achieve Th2 cytokine overproduction in neonates. This will be achieved by comparing the epigenetic state of the Th2 locus and Th2 cytokine production in wild-type and CNS-1-deficient neonates. Specific Aim 2 will examine the premise that hypomethylation of CNS-1 in fetal and neonatal life is essential for generating the neonatal Th2 bias. This will be tested by creating transgenic mice with forced methylation of CNS-1 throughout development. Constructs containing a CNS-1-targeted zinc finger protein coupled to the catalytic domain of the de novo DNA methyltransferase Dnmt3a will be created~ expression of the constructs will be confined to T lineage cells. The epigenetic state of the Th2 locus and Th2 function will be assessed in the transgenic mice. These studies will be the first to dissect genetic and epigenetic regulation at the Th2 cytokine locus in early ontogeny. Results from these studies will ultimately lead to interventional strategies aimed at improving pediatric health by mitigating the Th2 dominant state in early life.

描述（由申请人提供）：新生儿的免疫反应通常由抗炎 Th2 细胞因子的显着产生来定义，这种情况被称为新生儿 Th2 偏向。这种细胞因子分泌模式被认为导致幼年动物对感染的易感性以及 Th2 介导的疾病（例如哮喘）的发生。因此，旺盛的 Th2 功能是生命早期免疫的一个关键定义特征。了解这是如何发生的对于我们理解适应性免疫系统的个体发育至关重要。新生儿的 Th2 偏向反应部分归因于快速、高水平的 Th2 细胞因子产生。我们已经证明，Th2 细胞因子 IL-4 和 IL-13 都是由新激活的小鼠新生 CD4+ 细胞早期大量产生的。在成体 Th2 细胞中，高水平 Th2 细胞因子的协调表达需要一个称为保守非编码区 1 (CNS-1) 的基因间调节区。因此，CNS-1 遗传元件可能对新生儿早期、强健的 Th2 细胞因子产生发挥重要作用。事实上，这种 DNA 元件在个体发育早期以相对宽松的表观遗传状态存在。我们发现，与幼稚成人细胞不同，CNS-1 在幼稚胎儿和新生儿 T 谱系细胞中的 CpG 残基处低甲基化。这种低甲基化状态与新生儿 CD4+ 细胞快速、高水平 Th2 细胞因子的产生密切相关。 CNS-1 的甲基化在出生后迅速发生，在生命第一周结束时达到成人水平。 CNS-1 甲基化随着发育的增加而增加，与快速 Th2 细胞因子基因表达的逐渐沉默有关。总之，这些观察结果表明 CNS-1 可能在定义新生儿 Th2 偏好方面发挥着核心重要作用。我们的长期目标是了解遗传和表观遗传对早期生命 Th2 主导状态的贡献。在本提案中，我们将重点关注 Th2 细胞因子基因座中明确定义的 CNS-1 区域。我们的初步数据得出两个明确的假设。具体目标 1 将检验这样的想法：CNS-1 区域的物理存在是实现新生儿 Th2 细胞因子过量产生所必需的。这将通过比较野生型和 CNS-1 缺陷新生儿中 Th2 基因座的表观遗传状态和 Th2 细胞因子的产生来实现。具体目标 2 将检验以下前提：胎儿和新生儿生命中 CNS-1 的低甲基化对于产生新生儿 Th2 偏向至关重要。这将通过创建转基因小鼠进行测试 CNS-1 在整个发育过程中的甲基化。将创建含有与从头 DNA 甲基转移酶 Dnmt3a 催化结构域偶联的 CNS-1 靶向锌指蛋白的构建体，该构建体的表达将仅限于 T 谱系细胞。表观遗传将在转基因小鼠中评估 Th2 基因座的状态和 Th2 功能。这些研究将首次剖析个体发育早期 Th2 细胞因子基因座的遗传和表观遗传调控。这些研究的结果最终将产生旨在通过减轻生命早期 Th2 主导状态来改善儿科健康的干预策略。