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（由申请人提供）：经常用作核酸和内源性活性氧（ROS），在核酸中产生了8-氧-7,8-二氢甘氨酸（8-oxog），通常用作氧化应激的标志物。它是DNA中的前植物病变，因为它在复制过程中对腺嘌呤的潜力误导了。在DNA碱基切除途径（BER）途径中，通过8-oxog DNA糖基酶1（OGG1）从DNA中取出碱基8-oxog。减少的修复和产生的8-oxog积累与各种人类疾病和衰老有关，尽管其病因的作用知之甚少。炎症是大多数疾病的根源，包括呼吸道，心血管，中枢神经系统和致癌的根源。 Ragweed花粉提取物（RWPE：促氧化剂和抗原成分）增加了小鼠气道中基因组和OGG1活性的8-oxog水平。在RWPE暴露之前，敏化小鼠肺中OGG1（但没有其他氧化碱特异性DNA糖基化酶）的下调会显着降低过敏性气道炎症。重要的是，单独的EG8-OXOG（核外8-oxog）诱导小鼠肺中的趋化因子表达以及中性粒细胞的积累。我们的数据还表明，EG8-OXOG增加了1）激活的小GTPase； 2）RAS与RAF-1结合； 3）MEK1,2; 4）ERK1,2; 5）Rela-Ser276。 EG8-OXOG诱导了由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种影响。这些意外的观察结果使我们假设8-oxog通过OGG1从DNA中释放为信号分子，因为它能够增加活化的小GTPase的水平，从而启动了细胞激活事件的级联反应，从而增加了促炎性介体的表达和炎症的恶化。我们将通过追求三个具体目标来检验这一假设。我们将调查是否：目标1）8-oxog修复的缺乏使小鼠难治性炎症； AIM 2）OGG1的糖基化酶活性在翻译后调节，可从DNA释放EG8-OXOG； AIM 3）EG8-OXOG通过RAS-RAF-MEK/ERK-MSK1途径激活的NF-？B增强了促炎性介体的表达。肺部炎症的小鼠疾病模型将用于建立在培养细胞中产生的结果的病因相关性。这些目标的完成将提供第一个证据，即EG8-OXOG是通过充当诱导促炎性趋化趋化因子表达的信号分子的氧化应激介导的DNA损伤/修复和细胞反应之间的联系。我们的机械研究还应为新颖的治疗方法奠定基础。例如，将诱捕，清除或转化为非信号形式的药物不仅在气道中，而且在心血管中，中枢神经系统或肥胖相关炎症性疾病，等等。 公共卫生相关性：呼吸道疾病在全球范围内影响> 8亿人，在美国，大约有两千万个门诊就诊，200万次急诊室就诊和每年与这些疾病有关的50万个住院治疗。我们的新观察结果将氧化基因组损伤修复与炎症联系起来，随后识别其分子机制，为探索非常规的预防性治疗方法提供了抑制炎症的机会，从而抑制炎症并随后发病。