Modulators of DNA damage associated nucleo-mitochondrial communication in aging

描述（由申请人提供）：该K99/R 00项目的目标是检验细胞核中的遗传毒性应激触发信号传导事件的假设，该信号传导事件导致功能障碍性线粒体的积累，进而驱动细胞衰老和老化。该假设得到初步数据的支持，初步数据表明，细胞和小鼠中DNA修复核酸内切酶ERCC 1-XPF的耗尽导致氧化性DNA损伤的积累、过早的细胞衰老和老化，但也令人惊讶地导致线粒体功能障碍和活性氧物质的增加。此外，ERCC 1缺陷型C.秀丽线虫也显示出线粒体功能障碍的证据。ERCC 1- XPF仅用于修复核基因组，这表明核应激可以驱动线粒体异常。在共济失调毛细血管扩张症和Hutchinson-Gilford早衰综合征的小鼠模型和人类细胞中也观察到了类似的结果。在此，我们建议使用强大的遗传工具的创新组合来定义核基因组不稳定性触发线粒体功能障碍的分子机制。这些研究的意义在于，有可能确定新的信号传导机制，这些机制可以在治疗上靶向预防细胞衰老、老化和由于细胞随机损伤而引起的与年龄相关的疾病。该方法将在ercc-1C中进行全基因组RNAi筛选。elegans来鉴定抑制突变蠕虫中复合体1功能障碍的基因。这种无偏见的方法将产生影响线粒体功能的途径，以应对内源性遗传毒性应激，无疑是关于衰老机制的新假说。这将推动我成为一名独立调查员，这是这个项目的第二个重要目标。有针对性的初步筛选确定了该方法的可行性，并揭示了对DNA损伤反应和线粒体自噬至关重要的几个基因，包括ATM，p53，DRP 1和PINK 1，它们调节ercc-1蠕虫的线粒体功能。在线虫中发现的细胞核和线粒体之间的这些新联系将在小鼠和鼠细胞中进行研究。利用两个非常强大的模型系统的优势的创新方法将允许识别新的分子靶标，并支持将这种新知识快速转化为人类衰老。大多数65岁以上的人患有至少两种慢性退行性疾病。这些老年人的慢性疾病消耗了我们越来越大的医疗保健费用，并剥夺了个人的独立性和生活质量。开发针对所有这些疾病的主要风险因素的治疗方法，衰老本身，是一个有前途但具有挑战性的解决方案。第一步是确定驱动衰老的分子机制。该项目旨在确定响应内源性DNA损伤而驱动衰老的信号机制，这些损伤随着时间的推移在我们所有人中积累。这将揭示新的治疗靶点，可用于延长健康寿命。

DESCRIPTION (provided by applicant): The goal of this K99/R00 project is to test the hypothesis that genotoxic stress in the nucleus triggers signaling events that result in accumulation of dysfunctional mitochondria, which in turn drives cellular senescence and aging. The hypothesis is supported by preliminary data demonstrating that depletion of the DNA repair endonuclease ERCC1-XPF in cells and mice causes accumulation of oxidative DNA damage, premature cellular senescence and aging, but also surprisingly mitochondrial dysfunction and increased reactive oxygen species. Moreover, ERCC1-deficient C. elegans also show evidence of mitochondrial dysfunction. ERCC1- XPF is required only for the repair of the nuclear genome, suggesting that nuclear stress can drive mitochondrial abnormalities. Similar observations have been made in murine models and human cells of ataxia telangiectasia and Hutchinson-Gilford Progeria syndrome. Herein we propose to define the molecular mechanism(s) by which nuclear genomic instability triggers mitochondrial dysfunction using an innovative combination of powerful genetic tools. The significance of these studies is the possibility of identifying novel signaling mechanisms that could be targeted therapeutically to prevent cell senescence, aging and age-related diseases arising as a consequence of stochastic damage to cells. The approach will be a genome-wide RNAi screen in ercc-1 C. elegans to identify genes that suppress Complex 1 dysfunction in mutant worms. This unbiased approach will yield pathways that impact mitochondrial function in response to endogenous genotoxic stress and undoubtedly new hypotheses about mechanisms of aging. This will fuel my transition to becoming an independent investigator, a second important goal of this project. A targeted preliminary screen established the feasibility of the approach and revealed several genes critical for the DNA damage response and mitophagy, including ATM, p53, DRP1 and PINK1, that regulate mitochondrial function in ercc-1 worms. These novel links between the nucleus and mitochondria identified in nematodes will be pursued in mice and murine cells. The innovative approach of exploiting the strengths of two very powerful model systems will allow identification of novel molecular targets and support rapid translation of this new knowledge to human aging. The majority of individuals over the age of 65 years suffer from at least two chronic degenerative diseases. These chronic diseases of the elderly consume an increasingly large fraction of our health care costs and rob individuals of their independence and quality of life. Developing therapies to target the primary risk factor for all of these diseases, aging itself, is promising yet challenging solution. The first step is to define the molecular mechanisms that drive aging. This project aims to identify the signaling mechanisms that drive aging in response to endogenous DNA damage, which accumulates in all of us over time. This will reveal novel therapeutic targets that can be exploited to extend healthspan.