DNA Repair and Mitochondrial Dysfunction in T Cell Aging

T 细胞衰老过程中的 DNA 修复和线粒体功能障碍

• 批准号: 10543729
• 负责人: Cornelia M. Weyand
• 金额: $ 45.61万
• 依托单位: MAYO CLINIC ROCHESTER
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-12-20 至 2024-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10543729
• 关键词: Acceleration; Acetyl Coenzyme A; Affect; Age; Aging; Autoimmune Diseases; Behavior; Behavioral; Bioenergetics; Biogenesis; Biological Models; Biological Process; CASP1 gene; Caspase; Cell Aging; Cell Compartmentation; Cell Death; Cell Survival; Cells; Cessation of life; Chimera organism; Chronic; Citric Acid Cycle; Complex; Cytolysis; Cytoplasm; DNA; DNA Repair; Data; Defect; Deoxyribonucleases; Deterioration; Effector Cell; Elderly; Electron Transport; Elements; Engraftment; Extracellular Space; Extravasation; Funding; Generations; Glucose; Glycolysis; Health; Human; IL18 gene; Immune; Immune system; Impairment; In Vitro; Individual; Infection; Inflammasome; Inflammation; Inflammatory; Invaded; Life; Longevity; Lytic; Malignant Neoplasms; Maps; Mediating; Membrane; Metabolic; Metabolism; Mitochondria; Mitochondrial DNA; Modification; Molecular; Natural Immunity; Oxygen Consumption; Pathogenicity; Pathway interactions; Patients; Pentosephosphate Pathway; Peripheral; Phenotype; Predisposition; Process; Proteins; Proteolysis; Regulation; Repression; Resources; Rheumatoid Arthritis; Role; SCID Mice; Secure; Stress; Syndrome; Synovial Membrane; T-Lymphocyte; Testing; Tissues; Translating; Vascular Endothelial Cell; Work; adaptive immunity; age related; aged; cell age; cell type; cohort; comparative; cytokine; experimental study; frailty; gain of function; gene repression; in vivo; lipid biosynthesis; loss of function; mitochondrial dysfunction; mouse model; nuclease; overexpression; oxidation; oxidative damage; premature; prevent; programs; repaired; response; telomere; tissue injury; trait

Project Summary Aging of T lymphocytes has detrimental effects on the health of older individuals; rendering them susceptible to cancer, infection, and unopposed tissue inflammation. Older T cells are prone to differentiate into inflammatory effector cells, rapidly invading into peripheral tissues and promoting inflammatory tissue damage. Multiple biologic processes have been implicated in mediating T cell aging; including defective DNA repair, telomeric damage, membrane restructuring into invasive protrusions and reprogramming of cellular bioenergetics. T cell aging is accelerated by 20-30 years in patients with the inflammatory syndrome rheumatoid arthritis (RA), providing an excellent model system to study molecular, structural and behavioral abnormalities in old T cells. Work supported during the previous funding period has identified the DNA nuclease MRE11A as a key player in T cell aging. T cells from RA patients and from older healthy donors share the transcriptional repression of MRE11A. T cells low in MRE11A protein accumulate damaged telomeres and induce robust tissue inflammation with a signature of uncontrolled innate and adaptive immunity. Preliminary data show that MRE11Alow T cells also lack expression of the nuclease in mitochondria, leading to oxidative damage and cytoplasmic leakage of mitochondrial DNA (mtDNA). In the cytoplasm, oxidized mtDNA promotes NLRP3 inflammasome assembly, triggers caspase 1 activation and ultimately induces T cell lytic death. Here, we examine the hypothesis that mitochondrial stress is a driver of T cell aging and that the age-related decline of the DNA repair nuclease MRE11A exposes T cells to mitochondrial DNA leakage, inflammasome activation and ultimately to pyroptotic death. We have assembled key enabling resources to mechanistically study how mitochondrial MRE11A protects T cells from aging; including a large cohort of RA patients in whom T cells are pre-aged and a chimeric mouse model in which tissue inflammation is induced in engrafted human synovium to corroborate in vitro data by in vivo studies. Aim 1 examines mechanistically how MRE11A affects mitochondrial function, generation of ATP and ROS, glucose utilization and lipogenesis. The aim will connect mitochondrial DNA repair to oxygen consumption in the electron transfer chain and acetyl-CoA oxidation in the tricarboxylic acid cycle. Aim 2 investigates how MRE11A guides a mitochondrial stress defense program by preventing mtDNA release into the cytoplasm. In loss-of-function and gain-of-function experiments we will probe how MRE11A regulates inflammasome assembly, caspase 1 activation and T cell pyroptosis. Aim 3 will identify mechanisms through which MRE11A deficiency induces tissue inflammation. We will test how caspase 1-dependent cleavage of the pro-inflammatory cytokines IL-1 and IL-18 and of the membrane pore former gasdermin D drive tissue damage. These experiments will explore in vitro and in vivo how failed mitochondrial DNA repair causes T cell lysis, release of alarmins into the extracellular space and initiation of noninfectious inflammation.

项目摘要 T淋巴细胞的衰老对老年人的健康有害；使他们容易受到影响 癌症，感染和无反应的组织注射。较老的T细胞容易分化为炎症 效应细胞，迅速入侵周围组织并促进炎症组织损伤。多种的 在介导T细胞衰老中暗示了生物过程。包括缺陷的DNA修复，远程仪 损害，膜曲折为侵入性蛋白质以及细胞生物能学的重编程。 炎症综合征类风湿关节炎（RA），20 - 30年的衰老会加速衰老。 提供了一个出色的模型系统来研究旧T细胞中的分子，结构和行为异常。 在上一个资金期间支持的工作已将DNA核酸酶Mre11a确定为主要参与者 T细胞衰老。来自RA患者和老年健康供体的T细胞共享 mre11a。 MRE11a蛋白丙烯酸损伤损坏的T细胞造成端粒并诱导强大的组织注射 具有不受控制的先天和适应性免疫史的签名。初步数据显示Mre11alow t细胞 还缺乏线粒体中核酸酶的表达，导致氧化损伤和细胞质泄漏 线粒体DNA（mtDNA）。在细胞质中，氧化的mtDNA促进NLRP3炎性体组装， 触发caspase 1激活，并最终诱导T细胞裂解死亡。在这里，我们研究了以下假设 线粒体应力是T细胞衰老的驱动力，并且与年龄相关的DNA修复核酸酶下降 Mre11a将T细胞暴露于线粒体DNA泄漏，炎症体激活，并最终 凋亡死亡。我们已经组装了钥匙，使资源能够机械地研究线粒体 Mre11a可保护T细胞免受衰老的衰老；包括大量的RA患者，其中T细胞是预龄的，并且 一种嵌合小鼠模型，其中诱导组织注射的人类滑膜诱导以证实 体内研究的体外数据。 AIM 1考试机械地MRE11A如何影响线粒体功能， ATP和ROS的产生，葡萄糖利用和脂肪生成。目的将连接线粒体DNA修复 在电子转移链和三核酸周期中的乙酰-COA氧化中消耗氧。 AIM 2研究MRE11A如何通过防止MTDNA释放来指导线粒体应力防御计划 进入细胞质。在功能丧失和功能获得实验中，我们将探测MRE11A如何调节 炎性体组装，caspase 1激活和T细胞凋亡。 AIM 3将通过 MRE11A缺乏会诱导组织注射。我们将测试caspase 1依赖性裂解 促炎性细胞因子IL-1和IL-18以及膜孔的前气孔D驱动组织损伤。 这些实验将在体外探索和体内如何失败的线粒体DNA修复会导致T细胞裂解， 将警报释放到细胞外空间和非感染性炎症的倡议中。