Mechanistic insight into oxidative stress-mediated genome instability

氧化应激介导的基因组不稳定性的机制洞察 家长奖：R35GM142982 摘要 基因组不稳定的特征是遗传改变，包括DNA碱基突变，染色体断裂， 重排和不稳定是包括癌症在内的各种人类疾病的特征。染色体不稳定性 (CIN)由不准确的染色体分离引起，起源于端粒和着丝粒 功能障碍。大量的流行病学研究强调了氧化应激暴露在 端粒和着丝粒功能障碍的发生。然而，关键是，潜在的机制 对功能障碍的了解尚不清楚。氧化应激是由于两种物质之间产生的不平衡 活性氧物种与细胞抗氧化防御。它既来自内生来源，也来自 环境来源(线粒体新陈代谢、紫外线、空气污染、香烟烟雾)。它无处不在的亮点 正确认识其对人类健康影响的重要性。氧化应激的一个主要影响是 通过碱基切除修复(BER)途径修复的氧化DNA损伤的诱导 聚(ADP-核糖)聚合酶(PARP)是主要的作用因子。PARP1和PARP2负责聚(ADP- 核糖化)，一种蛋白质的翻译后修饰，调节其募集和相互作用 蛋白质靶标。这项提议的目标是：(I)揭示氧化应激介导的机制 基因组不稳定性及其对端粒和着丝粒的影响 稳定性和(Ii)破译PARP酶在保护端粒和着丝粒DNA中的作用 对DNA的氧化损伤。为此，我们正在利用一种独特和创新的化学光遗传工具 在端粒和着丝粒局部诱导DNA氧化损伤，而不影响其余部分 基因组。这将允许我们明确地将表型变化和PARP依赖机制与 端粒或着丝粒损害。这些项目旨在填补长期以来对PolyADP(ADP- 核糖基)在基因组的两个关键区域协调DNA修复。他们还将阐明如何 氧化应激是基因组不稳定的一个普遍因素，可以导致许多人类疾病。最终，我们的 这项工作将有助于开发针对基因组特定区域的新治疗策略 并为已经广泛用于癌症治疗的PARP抑制剂的合理设计和使用提供信息。

Mechanistic insight into oxidative stress-mediated genomic instability Parent award: R35GM142982 ABSTRACT Genome instability is characterized by genetic alterations that include DNA base mutations, chromosome breaks, rearrangements and instability, hallmarks of various human diseases including cancer. Chromosome instability (CIN) that results from inaccurate chromosomal segregation, originates from telomere and centromere dysfunctions. Numerous epidemiologic studies have highlighted the central role of oxidative stress exposures in the occurrence of telomere and centromere dysfunction. Critically, however, the mechanisms underlying the dysfunction are not clearly understood. Oxidative stress results from an imbalance between the production of reactive oxygen species and cellular antioxidant defenses. It arises from endogenous sources as well as from environmental sources (mitochondria metabolism, UV light, air pollution, cigarette smoke). Its ubiquity highlights the importance of properly understanding its impacts on human health. A major impact of oxidative stress is the induction of oxidative DNA damage that are repaired by the base excision repair (BER) pathway in which poly(ADP-ribose) polymerases (PARPs) are major actors. PARP1 and PARP2 are responsible for the poly(ADP- ribosyl)ation, a post-translational modification of proteins that modulates the recruitment and interactions of their protein targets. The goals of this proposal are to (i) uncover the mechanisms of oxidative stress-mediated genome instability with a focus on its impact on telomeres and centromeres, two genomic loci crucial for genome stability and (ii) decipher the contribution of PARP enzymes in the protection of telomeric and centromeric DNA upon oxidative DNA damage. To this end, we are leveraging a unique and innovative chemoptogenetic tool that induces oxidative DNA damage locally at telomeres and at centromeres without impacting the rest of the genome. This will allow us to unequivocally link phenotypic changes and PARP dependent mechanisms to the telomeric or centromeric lesions. These projects aim to fill a long-standing gap of knowledge on how poly(ADP- ribosyl)ation orchestrates DNA repair at two crucial regions of the genome. They will also shed light on how oxidative stress, an ubiquitous factor of genome instability, can drive numerous human diseases. Ultimately, our work will contribute to the development of novel therapeutic strategies targeting specific regions of the genome and inform the rational design and use of the PARP inhibitors already widely used in cancer treatments.