REGULATION OF MITOCHONDRIAL DNA-MEDIATED SIGNALING AND ITS CONTRIBUTION TO CELLULAR AND ORGANISMAL AGING

线粒体 DNA 介导的信号传导及其对细胞和有机体衰老的贡献

• 批准号: 10066304
• 负责人: Alva Gabriela Sainz
• 金额: $ 3.08万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-12-01 至 2022-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10066304
• 关键词: Age; Age of Onset; Aging; Animal Model; Autophagocytosis; Bacteria; Bacterial DNA; Bioenergetics; Biological Markers; Bone Marrow; Caloric Restriction; Cell Aging; Cell model; Cells; Chronic; Circular DNA; Cyclic GMP; Cytoplasm; DNA; DNA Packaging; Dependence; Development; Disease; Embryo; Fibroblasts; Genes; Health; Homeostasis; Immune response; Immune signaling; Immunity; In Vitro; Inflammaging; Inflammation; Inflammatory; Inflammatory Response; Interferons; Intervention; Knock-out; Life; Light; Link; Longevity; Lung; Measures; Mediating; Mitochondria; Mitochondrial DNA; Mitochondrial Proteins; Molecular; Molecular Biology; Morbidity - disease rate; Mus; Nuclear; Organ; Oxygen Consumption; Pathogenesis; Pathology; Pathway interactions; Physiological; Process; Proteins; Reactive Oxygen Species; Regimen; Regulation; Risk Factors; Role; Signal Transduction; Structure; Testing; Therapeutic Intervention; Tissues; Transcript; Wild Type Mouse; age related; anti aging; cell injury; cytokine; factor A; frailty; functional decline; immune activation; improved; in vivo; macrophage; mitochondrial DNA mutation; mitochondrial dysfunction; mortality; mouse model; new therapeutic target; novel therapeutic intervention; programs; response; senescence; sensor; transcription factor

Project Summary: Mitochondria are essential to life, as they not only produce the energy our cells need to maintain cellular homeostasis but are also involved in cellular signaling and immunity. Mitochondrial dysfunction has been implicated in the pathogenesis of various diseases. In addition, mitochondrial DNA (mtDNA), which can escape the mitochondria in circumstances that are still being elucidated, can activate cytoplasmic DNA sensors to trigger an immune response. Circulating mtDNA increases with age, indicating that release of mtDNA from the mitochondria and the subsequent activation of immune signaling may be a physiologically relevant process that may contribute to the development of age-related pathology. Our lab discovered that decreased levels of the mitochondrial protein Transcription Factor A, mitochondrial (TFAM), which functions in packaging mtDNA inside the mitochondria, leads to enhanced release of mtDNA into the cytoplasm. TFAM protein levels have been shown to decrease with age in various animal models, but the consequences of increased cytoplasmic mtDNA on the aging process has not been explored. Our lab has developed a Tfam heterozygous knock-out (Tfam+/-) mouse model of enhanced mtDNA release. Cells and tissues from these mice show no significant differences in oxygen consumption rates or mtDNA encoded transcripts when compared to wild-type (WT) mice despite having a 50% depletion of mtDNA and enhanced mtDNA release into the cytoplasm. Mouse embryonic fibroblasts and bone-marrow derived macrophages will be generated from WT and Tfam+/- mice to test the activation of autophagy in response to cytoplasmic mtDNA. Since autophagy proteins have been shown to regulate the activity of the cGAS-STING pathway when bacterial DNA acts as a trigger, the dependency of both cGAS activation, STING activation, and the presence of various autophagy proteins will be tested to fully elucidate the mechanism by which autophagy is activated in this context. Activation of cGAS is a key process in the activation of the senescence program. Cellular senescence underlies many age-related pathologies. Mouse primary lung fibroblasts will be generated from WT and Tfam+/- mice to test the effect of mtDNA-mediated signaling on the rate of onset of senescence. In addition, the onset of senescence in vivo and the contribution of mtDNA-mediated signaling to the development of age-related pathology will be investigated using a well-established frailty scale. This project will shed light on the mechanisms by which mtDNA-mediated signaling is regulated, and the contribution of mtDNA pro-inflammatory signaling to the progression of age-related pathology. Understanding the molecular biology underlying the aging-process will help identify novel therapeutic interventions to extend healthy lifespan.

项目概要： 线粒体对生命至关重要，因为它们不仅产生细胞维持细胞所需的能量 体内平衡，但也参与细胞信号传导和免疫。线粒体功能障碍已 参与多种疾病的发病机制。此外，线粒体DNA（mtDNA）可以逃脱 线粒体在仍在阐明的情况下可以激活细胞质 DNA 传感器 触发免疫反应。循环线粒体DNA随着年龄的增长而增加，表明线粒体DNA从 线粒体和随后的免疫信号激活可能是一个生理相关过程 这可能有助于与年龄相关的病理学的发展。我们的实验室发现， 线粒体蛋白转录因子 A，线粒体 (TFAM)，其功能是包装 mtDNA 线粒体内部，导致 mtDNA 释放到细胞质中的增强。 TFAM 蛋白水平 在各种动物模型中已被证明随着年龄的增长而减少，但细胞质增加的后果 线粒体DNA对衰老过程的影响尚未被探索。 我们的实验室开发了增强 mtDNA 释放的 Tfam 杂合敲除 (Tfam+/-) 小鼠模型。 这些小鼠的细胞和组织在耗氧率或 mtDNA 方面没有显着差异 与野生型 (WT) 小鼠相比，尽管 mtDNA 减少了 50%，但仍编码转录本 增强 mtDNA 释放到细胞质中。 小鼠胚胎成纤维细胞和骨髓来源的巨噬细胞将从 WT 和 Tfam+/- 产生 小鼠测试响应细胞质 mtDNA 的自噬激活。由于自噬蛋白具有 当细菌 DNA 充当触发器时，已被证明可以调节 cGAS-STING 通路的活性， cGAS 激活、STING 激活和各种自噬蛋白的存在的依赖性将是 进行测试以充分阐明在这种情况下激活自噬的机制。 cGAS的激活是衰老程序激活的关键过程。细胞衰老 是许多与年龄相关的病症的基础。小鼠原代肺成纤维细胞将从 WT 和 Tfam+/- 产生 小鼠测试 mtDNA 介导的信号传导对衰老发生率的影响。另外，发病时 体内衰老的影响以及 mtDNA 介导的信号对年龄相关疾病发展的贡献 将使用完善的衰弱量表来研究病理学。 该项目将揭示 mtDNA 介导的信号传导的调节机制，以及 mtDNA 促炎信号对年龄相关病理进展的贡献。理解 衰老过程背后的分子生物学将有助于确定新的治疗干预措施，以延长衰老过程 健康的寿命。