Role of TET1 in airway epithelium and childhood asthma

项目摘要 哮喘是儿童中最常见的慢性病，也是紧急护理和治疗的主要原因 儿童住院治疗。即使存在多种哮喘治疗方法，仍有较高的不完全有效率 哮喘治疗(40%-70%)突出了基于更好的非哮喘治疗的替代个体化治疗的必要性。 对疾病机制的理解。到目前为止，其病因和发病机制的分子机制研究进展尚不清楚。 儿童哮喘的发病机制尚不完全清楚。这一建议直接填补了这一知识空白， 测试一种解决疾病机制的新假说。甲基胞嘧啶双加氧酶TET1修饰5‘- 甲基胞嘧啶和调节基因功能。除了催化活性外，TET1蛋白还招募组蛋白 通过与转录因子(TF)相互作用修饰蛋白质复合体以调节组蛋白标记和 染色质的可及性，导致基因表达的激活和抑制。我们是第一个展示 在呼吸道上皮细胞中，较高的TET1启动子甲基化与较低的TET1表达和 儿童出现更频繁的哮喘症状。此外，我们还发现TET1在HBECs(人)中过表达 支气管上皮细胞)导致干扰素信号通路转录下调。包括- 目前，TET1在HBECs中的缺失显著增加了IRF7及其下游靶向I型的表达 HDM挑战后的干扰素。最后，Tet1的缺失导致肺组织中干扰素信号通路表达增加。 并导致哮喘小鼠模型的呼吸道高反应性和肺部炎症增强。 总的来说，这些数据支持TET1通过抑制I型哮喘在哮喘严重程度中的整体保护作用 干扰素信号。我们的数据有力地暗示了包括IRF7/STAT1/STAT2在内的蛋白质/蛋白质相互作用网络 TET1在I型干扰素诱导中的作用初步分析支持对IRF7 EX-1进行规范 TET1通过DNA甲基化和组蛋白修饰进行表达。众所周知，呼吸道上皮细胞- I型干扰素信号通路调节对外界刺激和刺激的先天和获得性免疫反应。 致敬哮喘的发展和恶化。总的来说，我们假设Tet1调节哮喘 通过DNA甲基化和组蛋白修饰抑制I型干扰素信号的表型- 上皮性细胞。我们的长期目标是了解儿童哮喘的表观遗传调控。这个 本R01应用的目的是确定TET1促进哮喘的机制(S)。这个AP- 禁令的实施将对公众健康产生重大影响。通过提议的目标，我们将1)证明 呼吸道上皮细胞TET1对I型干扰素信号通路的转录调控作用 2)明确TET1对正常人和正常人I型干扰素信号通路的调控机制(S) 哮喘上皮细胞；3)表明Tet1调节呼吸道病毒诱导的哮喘加重；以及4)促进 为哮喘和其他疾病提供新的治疗靶点，在这些疾病中，I型干扰素信号通路是ES- 明智的球员。

Project Summary Asthma is the most common chronic disease among children and the leading cause of emergency care and hospitalization in children. Even though multiple asthma therapies exist, the high rate of incomplete efficacy in asthma treatment (40%-70%) highlights the need for alternative individualized therapies based on a better un- derstanding of disease mechanisms. To date, the molecular mechanisms underlying the etiology and patho- genesis of childhood asthma are not fully understood. This proposal directly fills in this gap in knowledge and tests a novel hypothesis addressing disease mechanism. Methylcytosine dioxygenase TET1 modifies 5’- methyl-cytosine and regulate gene function. In addition to its catalytic activity, TET1 protein recruits histone modifying protein complexes through interaction with transcription factors (TFs) to regulate histone marks and chromatin accessibility, leading to both activation and repression of gene expression. We were the first to show that in airway epithelial cells, higher TET1 promoter methylation is associated with lower TET1 expression and more frequent asthma symptoms in children. Further, we found that overexpression of TET1 in HBECs (human bronchial epithelial cells) leads to transcriptional downregulation of interferon (IFN) signaling pathway. Consist- ently, loss of TET1 in HBECs significantly increases the expression of IRF7 and its downstream target type I IFN following HDM challenges. Finally, loss of Tet1 causes increased lung expression of IFN signaling path- way and leads to enhanced airway hyperresponsiveness and lung inflammation in mouse models of asthma. Collectively, these data support an overall protective role of TET1 in asthma severity through inhibition of type I IFN signaling. Our data strongly implicate a protein/protein interaction network including IRF7/STAT1/STAT2 in mediating the effects of TET1 on type I IFN induction. Preliminary analysis supports the regulation of IRF7 ex- pression by TET1 through DNA methylation and histone modification. It is well established that airway epitheli- al type I IFN signaling pathway regulates innate and adaptive immune responses to external stimuli and con- tributes to asthma development and exacerbation. Collectively, we hypothesize that Tet1 regulates asthma phenotypes by inhibiting type I interferon signaling through DNA methylation and histone modifications in air- way epithelial cells. Our long-term goal is to understand the epigenetic regulation of childhood asthma. The objective of this R01 application is to identify the mechanism(s) by which TET1 contributes to asthma. This ap- plication will have significant public health impact. Through the proposed aims, we will 1) demonstrate that the transcriptional regulation of type I IFN signaling pathway by TET1 in airway epithelium modulates asthma phe- notypes; 2) define the mechanism(s) by which TET1 regulates type I IFN signaling pathway in normal and asthmatic epithelium; 3) show that Tet1 regulates respiratory virus-induced asthma exacerbation; and 4) pro- vide novel therapeutic targets for asthma and other diseases in which type I IFN signaling pathway is an es- sential player.