Modulators of DNA damage associated nucleo-mitochondrial communication in aging

描述（由申请人提供）：这个K99/R00项目的目标是测试假设，即细胞核中的基因毒性应激触发信号事件，导致功能失调线粒体的积累，从而导致细胞衰老和衰老。这一假设得到了初步数据的支持，这些数据表明，细胞和小鼠中DNA修复内切酶ERCC1-XPF的缺失会导致氧化性DNA损伤的积累，细胞过早衰老，但也会导致线粒体功能障碍和活性氧的增加。此外，ercc1缺陷秀丽隐杆线虫也显示出线粒体功能障碍的证据。ERCC1- XPF仅用于核基因组的修复，这表明核应激可以驱动线粒体异常。类似的观察结果在小鼠模型和人类细胞共济失调毛细血管扩张和哈钦森-吉尔福德早衰综合征。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机制，这些机制可以用于靶向治疗，以防止细胞衰老、衰老和因细胞随机损伤而引起的与年龄相关的疾病。该方法将在ercc-1秀丽隐杆线虫中进行全基因组RNAi筛选，以确定抑制突变蠕虫中Complex 1功能障碍的基因。这种无偏倚的方法将产生影响线粒体功能的途径，以响应内源性基因毒性应激，毫无疑问，关于衰老机制的新假设。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，并揭示了几个对DNA损伤反应和线粒体自噬至关重要的基因，包括ATM、p53、DRP1和PINK1，它们调节ercc-1蠕虫的线粒体功能。这些在线虫中发现的细胞核和线粒体之间的新联系将在小鼠和小鼠细胞中进行研究。利用两种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点，并支持将这种新知识快速转化为人类衰老。65岁以上的大多数人至少患有两种慢性退行性疾病。老年人的这些慢性疾病消耗了我们越来越多的医疗保健费用，并剥夺了个人的独立性和生活质量。针对所有这些疾病的主要危险因素，即衰老本身，开发治疗方法是有希望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。该项目旨在确定内源性DNA损伤导致衰老的信号机制，内源性DNA损伤会随着时间的推移在我们所有人体内积累。这将揭示新的治疗靶点，可以用来延长健康寿命。

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.