Nitrosative Stress and Oral Bacteria

亚硝化应激和口腔细菌

基本信息

批准号：
10683718
负责人：
Janina P Lewis
金额：
$ 36.48万
依托单位：
VIRGINIA COMMONWEALTH UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2013
资助国家：
美国
起止时间：
2013-06-26 至 2026-08-31
项目状态：
未结题

项目摘要

Summary Nitrite and nitric oxide are widespread and robust signaling modulators that are emerging as potential new antibacterial therapeutic agents. The oral cavity has particularly high concentrations of nitrite, which can reach 1mM. Oral microorganisms have adapted to survive such high nitrosative stress exposure and, we expect, that disruption of these adaptation mechanisms will reduce growth and survival of bacteria in the oral environment. We know that Porphyromonas gingivalis, a periodontopathogen, has high tolerance of nitrosative stress. However, the complex signaling pathways setting the basis of this tolerance are yet to be determined in in this bacterium as well as in other oral bacteria. Using whole genome expression analysis we have identified hcp encoding newly re-designated S-nitrosylase as the most dramatically upregulated gene under nitrosative stress. Furthermore, we demonstrated that regulation of Hcp is dependent on an FNR- like regulator, HcpR, that employs novel hemin-dependent mechanism to sense nitrosative stress. We hypothesize that the HcpR-Hcp system is central for adaptation of P. gingivalis to nitrosative stress. Thus, we will first define the molecular mechanisms of P. gingivalis sensing nitrosative stress through determination of the structural and biochemical characteristics of HcpR. Since adaptation to nitrosative stress involves a novel enzymatic activity mediated by Hcp, we will characterize the Hcp-mediated S-nitrosylome using proteomic approaches. In addition, we will characterize the mechanism P. gingivalis Hcp employs to mediate protection against nitrosative stress. Finally, we will investigate the contribution of other putative regulatory and effector proteins in nitrosative stress defense in P. gingivalis. It is noteworthy, that we will verify the contribution of the mechanisms under host-pathogen setting. This knowledge will provide the tools to design agents that can compromise the defense mechanisms of the periodontopathogen and turn endogenous human host nitrite and nitric oxide into a weapon that inhibits growth of the bacterium and, ultimately, we can exploit it to treat periodontal disease. We predict that this work will shed light on nitrosative stress signaling mechanisms in a variety of other bacteria that carry similar nitrosative stress protection mechanisms to those in P. gingivalis.

概括亚硝酸盐和一氧化氮是广泛而鲁棒的信号调节剂，它们正在出现为潜在的新抗菌治疗剂。口腔的浓度特别高亚硝酸盐，可以达到1mm。口服微生物已经适应了如此高的生存亚硝化压力暴露，我们期望这些适应机制的破坏将会在口腔环境中降低细菌的生长和存活。我们知道卟啉念珠菌牙龈牙龈病，一种牙周病原具有硝化应激的耐受性。但是，综合体信号通路设定该公差的基础尚未确定在此细菌中以及其他口腔细菌。使用整个基因组表达分析，我们已经确定了HCP 编码新重新指定的S-亚硝基酶作为最显着上调的基因亚硝化应激。此外，我们证明了HCP的调节取决于FNR- 像调节剂一样，HCPR采用新型的血素依赖机制来感知亚硝化应激。我们假设HCPR-HCP系统对于适应牙龈疟原虫是硝化作用的核心压力。因此，我们将首先定义牙龈疟原假单胞菌的分子机制通过确定HCPR的结构和生化特征来压力。自从适应硝化应激涉及由HCP介导的新型酶促活性，我们将使用蛋白质组学方法来表征HCP介导的S-硝基基团。此外，我们将特征牙龈疟原虫HCP采用介导硝化剂的保护压力。最后，我们将调查其他推定的监管和效应子的贡献牙龈疟原虫中亚硝化应激防御中的蛋白质。值得注意的是，我们将验证宿主病原体下的机制的贡献。这些知识将提供工具设计可以损害牙周病原和防御机制的药物和将内源性人类宿主亚硝酸盐和一氧化氮变成抑制生长的武器细菌，最终我们可以利用它来治疗牙周疾病。我们预测这项工作将阐明携带的其他细菌中的亚硝化应力信号传导机制与牙龈疟原虫中的硝化应力保护机制相似。