Regulation and impact of lipid A modification in the pathogenesis of Porphyromonas gingivalis

脂质A修饰在牙龈卟啉单胞菌发病机制中的调控及影响

• 批准号: 10502017
• 负责人: Sumita Jain
• 金额: $ 36.93万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-06-09 至 2025-05-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10502017
• 关键词: Anaerobic Bacteria; Animal Model; Cell Wall; Cellular Structures; Characteristics; Chronic; Clinical; Data; Dental; Dental Plaque; Development; Diagnostic; Disease; Environmental Risk Factor; Enzymes; Excision; Exhibits; Future; Gene Expression; Gene-Modified; Genes; Gingivitis; Glucosamine; Gram-Negative Bacteria; Growth; Health; Human; Immune; Immune Evasion; In Vitro; Infection; Infection Control; Inflammation; Inflammatory; Innate Immune Response; Knowledge; Lead; Link; Lipid A; Longitudinal Studies; Mediating; Membrane; Modification; Molecular; Natural Immunity; Pathogenesis; Peptide Hydrolases; Periodontal Diseases; Periodontitis; Phenotype; Phosphoric Monoester Hydrolases; Play; Porphyromonas gingivalis; Positioning Attribute; Prevalence; Process; Production; Property; Proteins; Regulation; Regulator Genes; Reporting; Role; Sampling; Site; Structure; System; TLR4 gene; Testing; Therapeutic; Transcription Initiation Site; Variant; Vertebral column; Vesicle; Virulence; Virulence Factors; Work; diagnostic tool; dysbiosis; fitness; gingipain; immunoregulation; in vivo; inorganic phosphate; microbial; mutant; novel; pathogen; receptor; response; tool

Porphyromonas gingivalis is a sub-gingival Gram-negative bacterium that is closely associated with periodontitis, a chronic inflammatory disorder. Found in low numbers in healthy sites, its prevalence increases during disease, indicating it is well equipped to survive hostile inflammatory conditions. Animal models have demonstrated that P. gingivalis infection causes microbial dysbiosis in sub-gingival plaque with an ensuing increase in inflammation, which are the hallmarks of periodontal disease, marking it as a keystone pathogen. P. gingivalis evades the powerful innate immune response mediated by the receptor TLR4 by modifying its lipid A structure and has the unusual ability to elicit copious amounts of outer membrane vesicles (OMVs) armed with select virulence factors such as innate host protein destroying proteases. We have identified the crucial lipid A modification genes which are responsible for lipid A structural changes that elicit TLR4 evasion, and, additionally, contribute to OMV formation. These genes are a lipid A deacylase gene encoded by PGN_1123, and PG1773 and PG1587, which encode lipid A C1- and C4'-phosphatases respectively. In Preliminary Data, we demonstrate that all three of these genes are expressed higher in vivo in human plaque samples than in vitro and also exhibit higher expression in diseased sites than in health. However, nothing is known concerning how these genes are regulated in response to differing environmental conditions. We next demonstrate that lipid A phosphatase mutants have opposing effects on vesicle formation, suggesting regulation of PG1587 and PG1773 modulates the amount of OMVs produced. Therefore, in this application the following hypothesis will be tested: “P. gingivalis modifies its lipid A structure in response to local environmental conditions and this contributes both to its ability to survive in vivo and secrete virulence factors.” This hypothesis will be tested by the following three Specific Aims: Specific Aim 1. Characterize regulation of PGN_1123, PG1587 and PG1773 lipid A modification genes: Specific Aim 2. Determine the contribution of P. gingivalis lipid A structure and associated outer membrane molecules on OMV formation. Specific Aim 3. Comprehensive analysis of lipid A phosphatase gene expression in vivo. This work will significantly advance our knowledge of P. gingivalis pathogenesis in vivo. Future studies will include characterization of factors required for vesiculation. Overall, these studies will enable the development of diagnostic and therapeutic tools to control infection of this keystone pathogen.

牙龈卟啉单胞菌是一种牙龈下革兰氏阴性细菌，与牙龈卟啉单胞菌密切相关。 牙周炎，一种慢性炎症性疾病。在健康场所发现的数量很少，但其患病率却在增加 在疾病期间，这表明它有能力在恶劣的炎症条件下生存。动物模型有 证明牙龈卟啉单胞菌感染会导致龈下菌斑中的微生物失调，并随之而来 炎症增加，这是牙周病的标志，使其成为关键病原体。 牙龈卟啉单胞菌通过修饰其脂质来逃避由受体 TLR4 介导的强大先天免疫反应 一种结构，具有引发大量武装外膜囊泡（OMV）的不寻常能力 具有选择的毒力因子，例如破坏先天宿主蛋白的蛋白酶。我们已经确定了关键的 脂质A修饰基因负责引起TLR4逃避的脂质A结构变化，并且， 此外，有助于 OMV 的形成。这些基因是PGN_1123编码的脂质A脱酰酶基因， PG1773和PG1587，分别编码脂质A C1-和C4'-磷酸酶。 在初步数据中，我们证明所有这三个基因在人类体内表达量较高 斑块样本的表达水平高于体外样本，并且在患病部位也表现出比健康部位更高的表达。然而， 关于如何调节这些基因以响应不同的环境条件，我们一无所知。 接下来我们证明脂质 A 磷酸酶突变体对囊泡形成具有相反的作用，表明 PG1587 和 PG1773 的调节可调节 OMV 的产生量。 因此，在本申请中将检验以下假设：“牙龈卟啉单胞菌改变其脂质A结构 响应当地的环境条件，这有助于其在体内生存的能力 分泌毒力因子。”该假设将通过以下三个具体目标进行检验：具体目标 1。 表征 PGN_1123、PG1587 和 PG1773 脂质 A 修饰基因的调节：具体目标 2。 确定牙龈卟啉单胞菌脂质 A 结构和相关外膜分子对 OMV 的贡献 形成。具体目标3.体内脂质A磷酸酶基因表达的综合分析。 这项工作将显着增进我们对牙龈卟啉单胞菌体内发病机制的了解。未来的研究将 包括囊泡形成所需因素的表征。总体而言，这些研究将有助于发展 控制这种关键病原体感染的诊断和治疗工具。