Mechanisms for adaptation to oxidative stress in Porphyromonas gingivalis

描述（申请人提供）：牙龈卟啉单胞菌对氧化应激的适应机制牙龈卟啉单胞菌是一种黑色革兰氏阴性厌氧菌，是牙周病的重要病原。牙周袋的炎症环境表明这种生物具有促进其在氧化环境中生存的能力的特性。我们对牙龈卟啉卟啉菌和其他牙周病原体抗氧化应激机制的了解还存在空白。我们的假设是，在牙龈卟啉卟啉菌中，多种协调调节的机制对于防止氧化应激至关重要，并且在生物体的致病性中具有重要意义。在初步研究中，我们使用了一种全球性的方法来评估牙龈卟啉单胞菌等基因突变体在典型的牙周袋氧化应激环境下的细胞反应的转录谱。过氧化氢（H2O2）诱导的氧化应激反应确定了几个基因的诱导表达，包括一些已知参与氧化应激抗性的基因。氧化应激持续时间对转录有差异调节作用，DNA修复/修饰基因的上调主要发生在较短的暴露时间内。在长时间暴露于氧化应激时，一些已知参与蛋白质修复的基因被上调。在暴露时间的范围内，有几个假设基因的上调，这些基因以前没有被描述过。我们之前的报告也表明，与其他生物不同，在牙龈卟啉卟啉中，氧化应激诱导的DNA损伤的修复涉及8-氧-7,8-二氢鸟嘌呤（8-oxoG），可能以一种尚未描述的机制发生。在这个项目中，我们希望全面了解牙龈卟啉卟啉菌是如何适应牙周袋的氧化条件的，并评估它是否有助于其致病性。具体目标是：1。目的探讨氧化应激诱导基因在牙龈卟啉单胞菌存活/致病性中的作用。2. 鉴定和表征参与grpE基因座表达的调控序列和蛋白。3. 研究氧化应激条件下牙龈卟啉单胞菌等基因突变体的DNA损伤及其修复机制。总的来说，这些信息可以提供重要的线索，将允许开发新的治疗干预措施，以帮助控制和预防牙周病和其他牙龈卟啉卟啉菌相关疾病。

DESCRIPTION (provided by applicant): Mechanisms for adaptation to oxidative stress in Porphyromonas gingivalis Porphyromonas gingivalis, a black-pigmented, Gram-negative anaerobe, is an important etiologic agent of periodontal disease. The inflammatory environment of the periodontal pocket suggests that this organism has properties that will facilitate its ability live in an oxidative environment. There is a gap in our knowledge of mechanism(s) of oxidative stress resistance in P. gingivalis and other periodontal pathogens. It is our hypothesis that in P. gingivalis multiple coordinately regulated mechanisms are vital for protection against oxidative stress and are significant in the pathogenicity of the organism. In preliminary studies, we have used a global approach to assess the transcription profile of the cellular response of isogenic mutants of P. gingivalis in an environment of oxidative stress typical of the periodontal pocket. The response to hydrogen peroxide (H2O2)-induced oxidative stress identified the induced expression of several genes including some known to be involved in oxidative stress resistance. The duration of oxidative stress was shown to differentially modulate transcription with the up-regulation of DNA repair/modification genes mostly seen at a shorter exposure time. During a longer exposure to oxidative stress, several genes known to be involved in protein repair were up-regulated. Over the range of exposure times, there was an up-regulation of several hypothetical genes which have not been previously characterized. Our previous report has also demonstrated that, in contrast to other organisms, the repair of oxidative stress-induced DNA damage involving 8-oxo-7,8-dihydroguanine (8-oxoG) may occur by a yet-to-be described mechanism in P. gingivalis. In this project, we wish to gain a comprehensive understanding of how P. gingivalis adapts to the oxidative conditions typical of the periodontal pocket and evaluate whether it contributes to its pathogenicity. The Specific Aims are: 1. To characterize the specific role(s) of oxidative stress-induced genes in the survival/pathogenicity of P. gingivalis. 2. To identify and characterize the regulatory sequences and protein(s) involved in the expression of the grpE locus. 3. To characterize the DNA damage and mechanism(s) of repair in isogenic mutants of P. gingivalis under conditions of oxidative stress. Collectively, this information could provide important clues that would allow the development of novel therapeutic interventions to aid in the control and prevention of periodontal disease and other P. gingivalis-associated diseases. PUBLIC HEALTH RELEVANCE: The goal of this research is to characterize important factors that will facilitate the survival of the periodontal pathogen Porphyromonas gingivalis in the inflammatory environment of the periodontal pocket. Because this environment may cause severe damage to the organism and given its success as important cause of gum disease suggests that P. gingivalis has properties that will facilitate its ability live in a stress environment. Important factors that are essential for survival are prime targets for the development of novel therapeutics that will have a positive impact on human health.