Investigating the role of TET deficiency in promoting T cell expansion and inflammation

研究 TET 缺陷在促进 T 细胞扩增和炎症中的作用

基本信息

批准号：
10522926
负责人：
Anjana Rao
金额：
$ 54.9万
依托单位：
LA JOLLA INSTITUTE FOR IMMUNOLOGY
依托单位国家：
美国
项目类别：
财政年份：
2017
资助国家：
美国
起止时间：
2017-06-07 至 2027-05-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10522926
关键词：
Address Adoptive Transfer Affect Aging Aneuploidy Architecture Autoimmune Autoimmune Diseases Biochemical Bone Marrow Bone Marrow Transplantation CD4 Positive T Lymphocytes Cardiovascular Diseases Cell Culture System Cell Lineage Cell physiology Cells Chimera organism Chromosomal Instability Chromosome 17 Cytosine DNA DNA Damage DNA Methylation DNA Modification Methylases DNA Structure DNA Transposable Elements Data Development Dioxygenases Disease Enhancers Enterobacteria phage P1 Cre recombinase Enzymes FOXP3 gene Female Functional disorder G-Quartets Genes Genome Hematopoiesis Hematopoietic Hematopoietic Neoplasms Heterochromatin Histones Human Immune Immunocompetent Impairment In Vitro Individual Infiltration Inflammation Inflammatory Interferon Type I Interferons Interleukin-17 Interleukin-6 Iron Link LoxP-flanked allele Lymphocyte Lysine MHC antigen Malignant Neoplasms Methods Methylation Molecular Mouse Strains Mus Mutant Strains Mice Mutation Myelogenous Neurodegenerative Disorders Oncogenic Organ Outcome Oxides Oxygen Paper Pathway interactions Patients Penetrance Phenotype Proteins RNA Recurrence Regulatory T-Lymphocyte Repetitive Sequence Reporting Role Signal Transduction Solid Sterility Structure Syndrome System Systemic Lupus Erythematosus T-Cell Receptor T-Lymphocyte Testing Tetanus Helper Peptide Trisomy 17 Up-Regulation X Chromosome X Inactivation alpha ketoglutarate cancer cell cell type chromosome missegregation congenic cytokine demethylation experimental study fighting genome-wide improved in vivo innate immune sensing methyl group methylation pattern organ transplant rejection premalignant prevent promoter response stem stem cells systemic inflammatory response whole genome

项目摘要

Abstract DNA cytosine methylation (hereafter, DNA methylation) has a critical role in cell lineage specification as well as suppression of repetitive and transposable elements in the genome. DNA methyltransferases attach a methyl group to generate 5-methylcytosine (5mC); TET methylcytosine dioxygenases cause DNA demethylation by oxidizing the methyl group of 5mC to 5-hydroxymethylcytosine (5hmC) and beyond. We have shown that TET- deficient cell types display not only the expected increase in DNA methylation at promoters and enhancers, but also a paradoxical decrease in DNA methylation in heterochromatic regions of the genome. The consequences of these molecular features remain to be understood, but similar alterations in genome-wide DNA methylation patterns have been observed in cancer and aging. By studying the phenotypes of several mouse strains in which Cre recombinase was expressed either inducibly or developmentally in immune/ hematopoietic cell types, we showed that deletion of two or more Tet genes skewed cell lineage commitment in the relevant cell type, in a manner that correlated with changes in cell lineage commitment. More striking phenotypes, however, were that Tet2/3 fl/fl CD4Cre mice displayed massive TCR- dependent expansion of iNKT cells; and that Tet2/3 fl/fl Foxp3Cre mice developed a dominant proinflammatory phenotype observed in heterozygous female mice, in mixed bone marrow chimaeras, and in immunocompetent recipients injected with total CD4+ T cells from Tet2/3 fl/fl Foxp3Cre mice. This phenotype differs markedly from that observed in heterozygous Foxp3+/- females and in immunocompetent mice injected with Foxp3-deficient cells, which do not develop disease. In Aim 1, we will address the mechanisms underlying the striking expansion of Tet2/3-deficient iNKT cells by using adoptive transfer approaches in vivo and recently-developed cell culture systems that recapitulate the expansion in vitro. In Aim 2, we will ask whether the dominant autoimmune/ inflammatory phenotype of Tet2/3-deficient T regulatory cells requires, directly or indirectly, the decreased DNA methylation in heterochromatin observed in every TET-deficient cell type examined so far. Decreased DNA methylation in heterochromatin results in “heterochromatin dysfunction”, an aberrant cellular condition linked to autoimmune/ inflammatory disorders, cancer, aging, and neurodegenerative diseases, that stems from aberrant expression of transposable elements (TEs) and resulting DNA damage. DNA damage provokes “sterile inflammation”: activation of innate immune sensing pathways for RNA and DNA with consequent upregulation of type I interferons, interferon-induced genes and proinflammatory cytokines (e.g. IL-1b, IL-6, IFNg, IL-17) Our proposed experiments will add to our knowledge of how TET proteins influence T cell expansion and T regulatory function. More broadly, they will enhance our general understanding of the links connecting TET deficiency and TE expression with autoimmune/ inflammatory diseases, clonal hematopoiesis, a premalignant syndrome of older individuals associated with inflammation and cardiovascular disease, and cancer.

抽象的 DNA 胞嘧啶甲基化（以下简称 DNA 甲基化）在细胞谱系规范以及抑制基因组中的重复和转座元件。产生 5-甲基胞嘧啶 (5mC) 的 TET 甲基胞嘧啶双加氧酶导致 DNA 去甲基化；将 5mC 的甲基氧化为 5-羟甲基胞嘧啶 (5hmC) 及以上我们已经证明 TET-。缺陷细胞类型不仅显示出启动子和增强子处 DNA 甲基化的预期增加，而且基因组异染色质区域 DNA 甲基化也出现矛盾的减少。这些分子特征的具体情况仍有待了解，但全基因组 DNA 甲基化也发生了类似的变化在癌症和衰老中观察到了模式。通过研究几种诱导表达 Cre 重组酶的小鼠品系的表型或者在免疫/造血细胞类型的发育过程中，我们发现两个或多个 Tet 基因的缺失相关细胞类型中细胞谱系的倾斜，其方式与细胞谱系的变化相关然而，更引人注目的表型是 Tet2/3 fl/fl CD4Cre 小鼠表现出大量的 TCR-。 iNKT 细胞的依赖性扩增；Tet2/3 fl/fl Foxp3Cre 小鼠产生显性促炎性在杂合雌性小鼠、混合骨髓嵌合体和免疫功能正常的小鼠中观察到的表型注射来自 Tet2/3 fl/fl Foxp3Cre 小鼠的总 CD4+ T 细胞的受者这种表型与此显着不同。在杂合 Foxp3+/- 雌性小鼠和注射 Foxp3 缺陷的免疫功能小鼠中观察到的结果在目标 1 中，我们将探讨这种显着扩增的机制。通过使用体内过继转移方法和最近开发的细胞培养来培养 Tet2/3 缺陷的 iNKT 细胞在目标 2 中，我们将询问是否主要的自身免疫/ Tet2/3 缺陷型 T 调节细胞的炎症表型直接或间接需要 DNA 减少迄今为止，在每种 TET 缺陷细胞类型中均观察到异染色质甲基化 DNA 减少。异染色质甲基化导致“异染色质功能障碍”，这是一种与以下因素相关的异常细胞状况源自异常的自身免疫/炎症性疾病、癌症、衰老和神经退行性疾病转座元件 (TE) 的表达以及由此产生的 DNA 损伤。炎症”：激活 RNA 和 DNA 的先天免疫传感通路，从而导致上调 I 型干扰素、干扰素诱导基因和促炎细胞因子（例如 IL-1b、IL-6、IFNg、IL-17）我们提出的实验将增加我们对 TET 蛋白如何影响 T 细胞扩增和 T 细胞的了解。更广泛地说，它们将增强我们对连接 TET 的联系的总体理解。自身免疫/炎症性疾病、克隆造血、癌前病变的缺乏和 TE 表达与炎症、心血管疾病和癌症相关的老年人综合症。