The role of TET1 in childhood asthma

 描述(申请人提供)：哮喘是儿童中最常见的慢性病。虽然在哮喘的病因中，呼吸道上皮是过敏反应的主要驱动力，但目前还没有专门针对呼吸道上皮的哮喘治疗方法。标准的哮喘治疗，包括支气管扩张剂和皮质类固醇，并不是对所有哮喘患者都完全有效，特别是对有严重疾病的患者，这表明非常需要替代的个体化哮喘治疗方法。作为一种将5mC转化为5hmC的DNA去甲基酶，TET1在干细胞维持、神经活动和癌症中的作用最近被揭示。然而，TET1在哮喘中的作用尚不清楚。从我们的先导性暴露同胞研究中，我们发现与非哮喘儿童相比，哮喘儿童呼吸道上皮细胞中TET1的启动子甲基化水平降低，并且这种较低的甲基化水平与TET1的高表达水平相关。哮喘患者TET1表达的增加也与5hmC水平的显著升高有关。基于这些有趣和新颖的观察，我们假设TET1通过增加其靶基因在呼吸道上皮细胞中的羟甲基化而参与哮喘的发生。我们的长期目标是了解TET1在哮喘发病机制中的作用，并探索其潜在的治疗作用。此R21应用的目的是建立TET1与哮喘的关联并确定其靶点 这是进一步了解TET1在哮喘中的详细作用的后续R01应用的合乎逻辑的一步。我们的研究将首次确定TET1在调节呼吸道上皮细胞哮喘基因中的作用。使用来自两个独立队列和人类原代呼吸道上皮细胞的样本，我们建议使用以下特定目标来验证我们的假设：1)确定TET1甲基化和表达是否与哮喘有关，2)确定TET1在呼吸道上皮细胞中的靶基因组位置。我们希望我们的新研究将证明TET1通过其启动子的羟化来调节其目标哮喘基因的表达。R21中提出的研究具有重要意义，因为它将建立TET1及其产物5HmC与儿童哮喘和哮喘表型的关联，并确定它们在呼吸道上皮中的靶基因。这将为未来的研究打开大门，旨在利用动物模型和其他可用的工具进一步了解TET1和5HmC在哮喘发病中的作用，这可能导致新的哮喘治疗方法的开发，并对与TET1相关的其他疾病产生更广泛的影响。

 DESCRIPTION (provided by applicant): Asthma is the most frequent chronic disease among children. Although the airway epithelium is a major driver of the allergic responses in the etiology of asthma, no current asthma treatments specifically target the airway epithelium. Standard asthma treatments including bronchodilators and corticosteroids are not completely effec- tive in all asthmatics, especially in those with severe diseases, indicating a great need fo alternative personal- ized asthma therapy. As a DNA demethylase that converts 5mC to 5hmC, the role of TET1 in stem cell maintenance, neural activity and cancer have recently been revealed. However, the role of TET1 in asthma is unknown. From our pilot Exposure Sibling Study, we found that the promoter methylation of TET1 is decreased in asthmatic children compared to non-asthmatics in airway epithelial cells, and this lower methylation level correlates with higher expression levels of TET1. This increase in TET1 expression in asthmatics is also asso- ciated with a significant increase in 5hmC level. Based on these intriguing and novel observations, we hypoth- esize that TET1 contributes to asthma through increasing hydroxyl-methylation of its target genes in the airway epithelium. Our long-term goal is to understand the role of TET1 in asthma pathogenesis and explore its thera- peutic potentials. The objective of this R21 application is to establish the association of TET1 with asthma and to identify its target asthma genes in the airway epithelium, which is a logical step towards a subsequent R01 application aiming to further understand the detailed contributions of TET1 in asthma. Our study will be the first to establish the role of TET1 in regulating asthma genes in airway epithelial cels. Using samples from two in- dependent cohorts and human primary airway epithelial cells, we propose to test our hypothesis using the fol- lowing specific aims: 1) to determine whether TET1 methylation and expression are associated with asthma, 2) to determine the target genomic locations of TET1 in airway epithelial cells. We expect our novel study will demonstrate that TET1 regulates the expression of its target asthma genes through hydroxylation of their pro- moters. The research proposed in this R21 is significant because it will establish the association of TET1 and its product 5hmC with asthma and asthma phenotypes in children and identify their target genes in the airway epithelium. This will open the door for future research aiming to further understand the roles of TET1 and 5hmC in asthma development using animal models and other available tools, which may result in the devel- opment of novel asthma therapy and have broader impact in other diseases related to TET1.