Linkage of Lung Inflammation to 8-oxoguanine and OGG1

肺部炎症与 8-氧代鸟嘌呤和 OGG1 的联系

• 批准号: 8217167
• 负责人: ISTVAN Steven BOLDOGH
• 金额: $ 30.67万
• 依托单位: UNIVERSITY OF TEXAS MED BR GALVESTON
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-04-15 至 2015-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8217167
• 关键词: 8-hydroxyguanosine; A Mouse; Ablation; Accident and Emergency department; Acetylation; Adenine; Affect; Aging; Allergic inflammation; Ambrosia; Antigens; Antisense Oligonucleotides; Base Excision Repairs; Binding; Cardiovascular system; Cells; Cereals; Cultured Cells; DNA; DNA Repair; DNA biosynthesis; DNA glycosylase; Data; Disease; Disease model; Down-Regulation; EP300 gene; Environment; Epithelial Cells; Event; Excision; Exposure to; Foundations; Genome; Goals; Guanine; Hospitalization; Immune; Inflammation; Inflammation Mediators; Inflammatory; Inflammatory Response; Lesion; Link; Luciferases; Lung; Lung Inflammation; Lung diseases; MAP2K1 gene; MAPK3 gene; MEKs; Mediating; Mediator of activation protein; Methods; Microscopy; Mitogens; Modeling; Modification; Molecular; Monomeric GTP-Binding Proteins; Mus; Nerve; Neuraxis; Neutrophilia; Nucleic Acids; Obesity; Outpatients; Oxidative Stress; Pathogenesis; Pathway interactions; Pharmaceutical Preparations; Phase; Phosphorylation; Phosphotransferases; Plant Roots; Pollen; Predisposition; Prevention; Preventive; Process; Production; Purines; RNA; RPS6KA5 gene; Ras/Raf; Reaction; Reactive Oxygen Species; Refractory; Reporter; Research Personnel; Resistance; Role; Signaling Molecule; Small Interfering RNA; Stress; System; Testing; Therapeutic; Time; Transferase; Transgenic Organisms; Visit; airway epithelium; airway inflammation; allergic airway inflammation; base; carcinogenesis; chemokine; cytokine; human disease; mouse model; mutant; neutrophil; novel; novel therapeutic intervention; oxidation; oxidative DNA damage; pollutant; promoter; public health relevance; purine; repaired; respiratory; response; transcription factor

DESCRIPTION (provided by applicant): 8-oxo-7,8-dihydroguanine (8-oxoG), often used as a marker of oxidative stress, is generated in nucleic acids by environmental and endogenous reactive oxygen species (ROS). It is a premutagenic lesion in DNA because of its mispairing potential with adenine during replication. The base 8-oxoG is removed from the DNA by 8-oxoG DNA glycosylase 1 (OGG1) in the DNA base excision repair (BER) pathway. Decreased repair and resulting accumulation of 8-oxoG have been related to various human diseases and aging, although its etiological role is poorly understood. Inflammation is the root of most diseases including those of the respiratory, cardiovascular, central nervous systems and of carcinogenesis. Ragweed pollen extract (RWPE: has pro-oxidant and antigenic components) increases the 8-oxoG level in the genome and OGG1 activity in the mouse airways. Downregulation of OGG1 (but not of other oxidized-base specific DNA glycosylases) in the lungs of sensitized mice before RWPE exposure significantly decreased allergic airway inflammation. Importantly, EG8-oxoG (extragenomic 8-oxoG) alone induced chemokine expression in mouse lungs, along with neutrophil accumulation. Our data also show that EG8-oxoG increased the levels of 1) activated small GTPases; 2) Ras to Raf-1 binding; and phosphorylation of 3) MEK1,2; 4) ERK1,2; and 5) RelA-Ser276. EG8-oxoG induced luciferase expression driven from the CXCL-8 promoter. Notably, other oxidized purine bases had no such effects. These unexpected observations led us to hypothesize that 8-oxoG liberated from DNA by OGG1 functions as a signaling molecule by virtue of its ability to increase levels of activated small GTPases, thereby initiating cascades of cellular activation events leading to increased pro-inflammatory mediator expression and exacerbation of inflammation. We will test this hypothesis by pursuing three Specific Aims. We will investigate whether: Aim 1) deficiency in 8-oxoG repair renders mice refractory to inflammation; Aim 2) OGG1's glycosylase activity is post-translationally modulated for release of EG8-oxoG from DNA; and Aim 3) EG8-oxoG enhances expression of pro-inflammatory mediators via NF-?B, activated by the Ras-Raf-MEK/ERK- MSK1 pathway. A mouse disease model for lung inflammation will be used to establish the etiological relevance of our results generated in cultured cells. Completion of these aims will provide the first evidence that EG8-oxoG is the link between oxidative stress- mediated DNA damage/repair and cellular responses, by acting as a signaling molecule inducing pro- inflammatory chemokine expression. Our mechanistic studies should also lay the foundation for novel therapeutic approaches. For example, drugs that trap, scavenge, or convert EG8-oxoG into a non-signaling form should be beneficial for the prevention of inflammatory processes not only in airways, but also in cardiovascular, and central nervous systems or in obesity-associated inflammatory diseases, among others. PUBLIC HEALTH RELEVANCE: Respiratory diseases affect >eight hundred million people worldwide, and in the US there are approximately twenty million outpatient visits, two million emergency room visits, and half million hospitalization per year related to these diseases. Our novel observations linking oxidative genome damage repair to inflammation and subsequently identifying its molecular mechanism provide an opportunity to explore unconventional preventive therapeutic approaches to inhibit inflammation and thereby subsequent pathogenesis.

描述(申请人提供)：8-氧代-7，8-二氢鸟嘌呤(8-oxoG)，通常被用作氧化应激的标志，由环境和内源性活性氧(ROS)在核酸中产生。它是DNA中的一种前突变损伤，因为它在复制过程中与腺嘌呤有错配的潜力。在DNA碱基切除修复(BER)途径中，8-oxoG由8-oxoG DNA糖基酶1(OGG1)从DNA上移除。修复减少和由此导致的8-oxoG积累与各种人类疾病和衰老有关，尽管其病因作用尚不清楚。炎症是大多数疾病的根源，包括呼吸系统、心血管系统、中枢神经系统和致癌的疾病。豚草花粉提取物(RWPE：具有促氧化剂和抗原性成分)可增加基因组中的8-oxoG水平和小鼠呼吸道中的OGG1活性。在RWPE暴露前，致敏小鼠肺中OGG1(但不是其他氧化碱基特定DNA糖基酶)的下调显著减少过敏性呼吸道炎症。重要的是，eG8-oxoG(基因组外8-oxoG)单独诱导了小鼠肺内趋化因子的表达，并伴随着中性粒细胞的聚集。我们的数据还表明，eG8-oxoG增加了1)激活的小GTP酶；2)RAS与Raf-1的结合；以及3)MEK1、2、4)ERK1、2和5)RELA-Ser276的磷酸化水平。EG8-oxoG诱导CXCL-8启动子驱动的荧光素酶表达。值得注意的是，其他氧化的嘌呤碱没有这样的影响。这些意想不到的观察使我们假设OGG1从DNA中释放出的8-oxoG作为信号分子发挥作用，因为它能够增加激活的小GTP酶的水平，从而启动细胞激活事件的级联反应，导致促炎介质表达增加和炎症加剧。我们将通过追求三个具体目标来检验这一假设。我们将研究：目的1)8-oxoG修复缺陷是否使小鼠难以抗炎；目的2)OGG1‘S糖基酶活性在翻译后被调节以释放eG8-oxoG；以及目的3)eG8-oxoG通过Ras-Raf-MEK/ERK-MSK1途径激活的核因子-βB增强促炎介质的表达。肺部炎症的小鼠疾病模型将被用来建立我们在培养细胞中产生的结果的病因学相关性。这些目标的完成将提供第一个证据，证明eG8-oxoG是氧化应激介导的DNA损伤/修复和细胞反应之间的联系，作为诱导促炎趋化因子表达的信号分子。我们的机制研究也应该为新的治疗方法奠定基础。例如，捕获、清除或将eG8-oxoG转化为非信号形式的药物应该有利于预防炎症过程，不仅在呼吸道，而且在心血管和中枢神经系统或肥胖相关的炎症性疾病中也是如此。 公共卫生相关性：呼吸系统疾病影响全球8亿人，在美国，每年与这些疾病有关的门诊就诊约为2000万人次，急诊室就诊约200万人次，住院治疗约50万人次。我们的新观察将氧化基因组损伤修复与炎症联系起来，并随后确定了其分子机制，为探索非传统的预防性治疗方法以抑制炎症从而抑制随后的发病机制提供了机会。