How interactions of oral bacteria enhance resistance to innate immunity

口腔细菌的相互作用如何增强对先天免疫的抵抗力

• 批准号: 7847475
• 负责人: Matthew Ramsey
• 金额: $ 3.1万
• 依托单位: UNIVERSITY OF TEXAS AT AUSTIN
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-06-01 至 2011-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7847475
• 关键词: Affect; Alternative Complement Pathway; Architecture; Bacteria; Bacterial Infections; Binding; Biological Assay; Carbon; Cell Survival; Cell surface; Cells; Coculture Techniques; Complement; Complement Activation; Complement Factor H; Cytolysis; Data; Dental; Environment; Epithelial Cells; Event; Exhibits; Exposure to; Gene Expression; Genes; Genetic; Gingiva; Goals; Gram-Negative Bacteria; Growth; Health; Human; Human body; Hydrogen Peroxide; Immune; Immune response; Immune system; Immunity; Immunofluorescence Immunologic; In Situ; Infection; Integration Host Factors; Knowledge; Laboratories; Lactic acid; Lead; Measures; Membrane Proteins; Microbial Biofilms; Microscopy; Mission; National Institute of Dental and Craniofacial Research; Natural Immunity; Oral; Oral cavity; Organism; Periodontitis; Phagocytes; Phagocytosis; Play; Primates; Process; Proteins; Reporter; Research; Resistance; Resources; Role; Serum; Signal Transduction; Source; Streptococcus gordonii; Testing; Work; antimicrobial; craniofacial; genetic regulatory protein; immune resistance; improved; killings; microbial; novel; oral bacteria; oral pathogen; oral streptococci; organic acid; promoter; public health relevance; sugar; uptake

DESCRIPTION (provided by applicant): The bacterium Aggregatibacter actinomycetemcomitans (Aa) grows in the human oral cavity and is a causitive agent of periodontitis. In the oral cavity, Aa must grow in close proximity to oral microbial flora, the most numerous of which are often oral streptococci, such as Streptococcus gordonii (Sg), that are able to ferment sugars into organic acids and release hydrogen peroxide (H2O2). Our preliminary results show that Aa responds to H2O2 from Sg by upregulating a gene (aplA) involved in defense against innate immunity. Thus, Aa appears to be using H2O2 as an anticipatory signal to increase resistance to host innate immunity. The goal of our proposal is to understand how co-culture with oral streptococci impacts Aa survival in the presence of host innate immune factors, and we propose two aims to accomplish this goal. My first aim tests if co-culture with Sg diminishes opsonization and phagocytosis of Aa. I hypothesize that co-culture will reduce opsonization and phagocytosis and plan to test this by quantifying opsonizing proteins Aa cell surface by immunofluoresence as well as measuring levels of uptake of Aa and Sg by phagocytic cells. Our second aim tests if co-culture biofilm increases protection from innate immunity, whether by biofilm architecture or spatial proximity of cells to induce genes involved in immune defense. We hypothesize that co-culture biofilms will be more resistant to innate immune factors. To test this hypothesis we will measure Aa and Sg cell survival in co-culture vs pure culture biofilms by plate count assay and microscopy after exposure to cxjmplement active serum and phagocytic cells. We will also utilize fluorescent reporter fusions to the Aa aplA promoter to determine if its expression is dependent on proximity to Sg in the co-culture biofilm and if this impacts survival of either species while in close proximity. Understanding these events provides us with a better knowledge of interactions Aa must have with its neighbors that allow it to resist the human immune system. Public Health Relevance: The mission of the National Institute of Dental and Craniofacial Research (NIDCR) is to improve oral, dental and craniofacial health through research. We fulfill that mission by determining key relationships that an oral pathogen must have in its natural environment and how they impact survival from host immunity. Bacterial infections are often studied in pure culture despite the fact that multi-species infections occur often in the human body. We wish to further characterize the unique observation that different bacterial species impact another's resistance to the human immune system and my lead to new strategies for antimicrobial therapy.

描述(申请人提供)：细菌Aggregatibacter放线菌(AA)生长在人类口腔中，是牙周炎的致病菌。在口腔中，AA必须生长在靠近口腔微生物区系的地方，其中最多的通常是口腔链球菌，如戈登链球菌(Sg)，它们能够将糖发酵成有机酸并释放过氧化氢(H2O2)。我们的初步结果表明，AA通过上调参与防御天然免疫的基因(APLA)来响应来自Sg的H_2O_2。因此，AA似乎利用过氧化氢作为一种预期信号来增加对宿主天然免疫的抵抗力。我们建议的目标是了解在宿主固有免疫因素存在的情况下，与口腔链球菌共培养如何影响AA生存，我们提出两个目标来实现这一目标。我的第一个目标是测试与Sg共培养是否会减少AA的调理和吞噬作用。我假设共培养将减少调理和吞噬，并计划通过免疫荧光定量调理蛋白质AA细胞表面以及测量吞噬细胞摄取AA和Sg的水平来测试这一点。我们的第二个目标是测试共培养生物膜是否通过生物膜结构或细胞的空间接近来诱导参与免疫防御的基因来增加对先天性免疫的保护。我们假设共培养的生物膜对先天免疫因子更具抵抗力。为了验证这一假设，我们将通过平板计数法和显微镜观察Aa和Sg细胞在共培养和纯培养生物膜中的存活率，并将其暴露于Cxjmplement活性血清和吞噬细胞中。我们还将利用荧光报告融合到AA APLA启动子，以确定其表达是否依赖于共培养生物膜中Sg的接近，以及这是否影响任何一个物种的生存。了解这些事件为我们提供了更好的知识，让我们了解AA必须与其邻居进行的相互作用，使其能够抵抗人类免疫系统。公共卫生相关性：国家牙科和颅面研究所(NIDCR)的使命是通过研究改善口腔、牙齿和颅面的健康。我们通过确定口腔病原体在其自然环境中必须具有的关键关系以及它们如何影响宿主免疫的生存来完成这一使命。细菌感染通常是在纯培养中研究的，尽管多物种感染经常发生在人体内。我们希望进一步确定不同细菌物种影响另一种细菌对人类免疫系统的抵抗力这一独特观察的特征，并为抗菌治疗带来新的策略。