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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且强大的信号调节剂，正在作为新兴的信号调节剂潜在的新型抗菌治疗剂。口腔内浓度特别高亚硝酸盐含量可达1mM。口腔微生物已经适应了如此高的生存条件亚硝化应激暴露，我们预计，这些适应机制的破坏将减少口腔环境中细菌的生长和存活。我们知道，卟啉单胞菌 gingivalis 是一种牙周病原菌，对亚硝化应激具有高度耐受性。然而，复杂的该细菌中奠定这种耐受性基础的信号通路尚未确定以及其他口腔细菌。通过全基因组表达分析，我们鉴定了 hcp 编码新近重新指定的 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 的调节依赖于 FNR- 像调节器 HcpR 一样，它采用新颖的血红素依赖性机制来感知亚硝化应激。我们假设 HcpR-Hcp 系统是牙龈卟啉单胞菌适应亚硝化的核心压力。因此，我们首先定义牙龈卟啉单胞菌传感亚硝基的分子机制通过测定 HcpR 的结构和生化特征来产生应激。自从对亚硝化应激的适应涉及一种由 Hcp 介导的新型酶活性，我们将使用蛋白质组学方法表征 Hcp 介导的 S-亚硝基组。此外，我们将描述牙龈卟啉单胞菌 Hcp 用于介导亚硝化保护的机制压力。最后，我们将研究其他假定的监管和效应器的贡献牙龈卟啉单胞菌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-病原体环境下机制的贡献。这些知识将提供工具设计可以损害牙周病原体防御机制的药物，将内源性人体宿主亚硝酸盐和一氧化氮变成抑制细菌生长的武器细菌，最终我们可以利用它来治疗牙周病。我们预测这项工作将揭示多种其他携带亚硝化应激信号的细菌的机制与牙龈卟啉单胞菌相似的亚硝化应激保护机制。