Role of DNA Glycosylase OGG1 in Oxidative Stress-Induced Innate Inflammation

氧化DNA碱基损伤与炎症过程有关，但在 尽管做出了相当大的努力，但仍要了解他们的疾病病因。最丰富的DNA碱基损伤，8- 氧鸟苷(8-oxoG)与炎症、各种与年龄相关的疾病和衰老过程有关。它是 8-oxoG DNA糖基酶(0GG1)和DNA碱基切除修复(BER)从DNA中切除 路径。出乎意料的是，Oggi基因敲除小鼠的超生理学8-oxoG水平没有显示出明显的 病理；事实上，它们增强了对炎症的抵抗力。DNA中8-oxoG水平的增加是 呼吸道氧化暴露的最早事件；然而，它在触发炎症中的作用是 疑似但不了解。我们有了意想不到的发现，表明OGGI从 氧化暴露前的呼吸道上皮细胞显著降低先天炎症反应；2) 0GG1结合其修复产物，游离的8-oxoG碱基；3)OGG1？8-oxoG复合体具有鸟嘌呤核苷酸 交换因子活性，4)增加激活的小RAS GTP酶的水平，5)导致激活 核因子-KB/RELA。项目3试图建立一种新的范式，在该范式中，0GG1启动的DNA BER是病因 与氧化应激诱导的致炎基因表达和炎症有关。这将通过以下方式完成 追求三个特定的目标：目的1)建立OGGI启动的DNA BER在炎症细胞中的作用 氧化应激暴露后肺内蓄积；目的2)阐明OGGI在激活 核因子-kB/RELA通路；以及目的3)确定OGGI诱导的触发促炎的信号通路(S) 基因表达和炎症。我们的假设将通过基因敲除/转基因技术进行验证 小鼠和细胞系以及基于siRNA的基因消融等最先进的分子技术 表达，实时聚合酶链式反应，共聚焦显微镜，细胞因子/趋化因子和RNA阵列。这些研究 应该是第一个确定OGGI的作用，并确定其新的信号通路，以促进天生 肺部发炎。由于OGG1对8-oxoG的修复是连续的，这些研究的结果也可能 有助于了解过敏性哮喘、慢性阻塞性肺疾病、 呼吸道重塑和肺部恶性肿瘤；每一种都对个人、家庭、健康构成重大负担 护理系统和整个社会，在美国和世界各地。我们令人信服的初步数据， 在此POI中的出色合作，以及UTMB出色的资源和智力环境，使 我们是唯一适合做这项工作的人。

Oxidative DNA base damage is linked to inflammatory processes, but there are major shortcomings in understanding their disease etiology despite considerable efforts. The most abundant DNA base lesion, 8- oxoguanine (8-oxoG) is linked to inflammation, various age-associated diseases, and aging processes. It is excised from DNA by the 8-oxoG DNA glycosylase (0GG1) and the DNA base excision repair (BER) pathway. Unexpectedly, supraphysiological 8-oxoG levels in Oggi knockout mice do not show major pathologies; in fact, they have increased resistance to inflammation. An increase in 8-oxoG levels in DNA is the earliest event upon oxidative exposure of airways; however, its role in triggering inflammation is suspected but not understood. We have made unexpected discoveries showing that 1) OGGI depletion from the airway epithelium before oxidative exposure significantly decreased innate inflammatory responses; 2) 0GG1 binds its repair product, free 8-oxoG base; 3) the OGG1¿8-oxoG complex has a guanine nucleotide exchange factor activity that 4) increases levels of activated small Ras GTPases and 5) leads to activation of NF-KB/RelA. Proiect 3 seeks to establish a novel paradigm in which 0GG1-initiated DNA BER is etiologically linked to oxidative stress-induced proinflammatory gene expression and inflammation. This will be done by pursuing three Specific Aims, to: Aim 1) establish the role of OGGI-initiated DNA BER in inflammatory cell accumulation after oxidative stress exposure in the lungs; Aim 2) elucidate the role of OGGI in activation of the NF-kB/RelA pathway; and Aim 3) identify the OGGI-induced signaling pathway(s) that trigger proinflammatory gene expression and inflammation. Our hypotheses will be tested using knock-out/transgenic mice and cell lines and such state-of-the-art molecular techniques as siRNA-based ablation of gene expression, real-time PCR, confocal microscopy, and cytokine/chemokine and RNA arrays. These studies should be the first to establish the role of OGGI and identify its novel signaling pathways that facilitate innate lung inflammation. As repair by 8-oxoG by OGG1 is continuous, the results from these studies may also shed light on understanding chronic inflammation in allergic asthma, chronic obstructive pulmonary disease, airway remodeling and lung malignancies; each poses a significant burden on individuals, families, health care systems and the entire society, here in the US and worldwide. Our compelling preliminary data, excellent collaborations in this POI, and UTMB's outstanding resources and intellectual environment make us uniquely suited to do this work.