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，因为它们不仅产生我们的细胞维持细胞活力所需的能量， 体内平衡，但也参与细胞信号传导和免疫。线粒体功能障碍一直是 与多种疾病的发病机制有关。此外，线粒体DNA（mtDNA），它可以逃脱 线粒体在仍在阐明的情况下，可以激活细胞质DNA传感器， 引发免疫反应循环中的mtDNA随着年龄的增长而增加，这表明线粒体DNA的释放是随着年龄的增长而增加的。 线粒体和随后的免疫信号传导的激活可能是生理学上相关的过程 这可能会导致与年龄相关的病理学的发展。我们的实验室发现， 线粒体蛋白质转录因子A，线粒体（TFAM），其功能是包装线粒体DNA 在线粒体内，导致线粒体DNA释放到细胞质中的增强。TFAM蛋白水平具有 在各种动物模型中显示随着年龄的增长而减少，但细胞质内的增加的后果是， 线粒体DNA对衰老过程的影响尚未探讨。 我们的实验室已经开发了一种增强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线粒体DNA上没有显着差异 与野生型（WT）小鼠相比，尽管线粒体DNA缺失50%， 增强mtDNA释放到细胞质中。 小鼠胚胎成纤维细胞和骨髓源性巨噬细胞将由WT和Tfam+/- 小鼠来测试响应于细胞质mtDNA的自噬的激活。由于自噬蛋白具有 当细菌DNA作为触发物时，已经显示出调节cGAS-STING途径的活性， cGAS激活、STING激活和各种自噬蛋白的存在两者的依赖性将被确定。 测试以充分阐明自噬在这种情况下被激活的机制。 cGAS的激活是衰老程序激活的关键过程。细胞衰老 是许多与年龄有关的疾病的基础。小鼠原代肺成纤维细胞将由WT和Tfam+/- 小鼠来测试mtDNA介导的信号传导对衰老开始速率的影响。此外， 以及线粒体DNA介导的信号传导对衰老相关的细胞凋亡的作用。 将使用完善的虚弱量表研究病理学。 该项目将阐明mtDNA介导的信号转导的调节机制， mtDNA促炎信号传导对年龄相关病理学进展的贡献。理解 衰老过程的分子生物学基础将有助于确定新的治疗干预措施， 健康的寿命。