Interaction of Treponema denticola virulence factors with neutrophils to modulate polymicrobial responses

项目摘要/摘要 牙周病以某种形式影响高达47%的成年人口，并与许多严重的 系统性疾病。尽管牙周病带来了巨大的健康和经济负担，但仍有许多 尚不清楚口腔中非生物细菌群落和免疫反应的影响。 齿密螺旋体与连翘坦纳氏菌和牙龈卟啉单胞菌共同构成了红色 细菌的“复合体”，与严重的牙周病显著相关。主要的外鞘蛋白 齿状毛滴虫(T.denticola)的主要致病因子(MSP)对包括中性粒细胞在内的宿主细胞功能有调节作用。中性粒细胞是关键 机体天然防线的细胞，可在牙周组织中抵抗病原体 疾病，它们就会变得无效。重要细胞脂质--磷脂酰肌醇(PIP)的调节 代谢产物，通过适当的脂激酶和磷酸酶活性，是协调中性粒细胞的关键 功能和驱动免疫反应。MSP通过抑制PI3K和PI3K而破坏细胞内PIP平衡 磷酸酶和张力蛋白同源蛋白(PTEN)的激活。尽管他是登革热最著名的 毒力因子，MSP通过操纵MSP限制中性粒细胞趋化能力的确切机制 PI3K/PTEN脂代谢途径尚不清楚。我们假设，在孤立的情况下接触MSP 形成或作为外膜小泡的一个组成部分，将限制中性粒细胞对齿状毛滴虫的反应，但 也次要到其他成员的“红色复合体”，促进细菌的相互作用和存活 口腔内的多菌生物膜。这个项目的总体目标是描述齿纹夜蛾是如何 损害中性粒细胞功能作为一种调节先天免疫反应的手段，目的是确定 MSP干扰PI3K信号转导和磷酸酶激活的机制以及MSP如何 MSP与中性粒细胞的相互作用支持了严重牙周病的细菌环境。 这些目标将通过1)确定MSP在激活脂质磷酸酶SHIP1中的作用来实现 以及MSP如何与不同亚型的脂激酶PI3K相互作用来改变正常的中性粒细胞信号 反应和2)表征齿状毛滴虫和MSP与中性粒细胞的相互作用改变 中性粒细胞对其他病原体的反应能力。这项工作将填补对致病性知识的空白。 以及它在多菌感染中中性粒细胞反应的操纵中的作用。 此外，本提案中概述的指导和培训计划将有助于实现 未来发展成功的独立学术研究项目所需的专业技能。

Project Summary/Abstract Periodontal disease affects up to 47% of the adult population in some form and is linked to a number of serious systemic diseases. Despite the significant health and economic burden of periodontal disease, much remains unknown about the effect of the dysbiotic bacterial community and immune response in the oral cavity. Treponema denticola, along with Tannerella forsythia and Porphyromonas gingivalis, compose the “red complex” of bacteria, prominently associated with severe periodontal disease. The major outer sheath protein (Msp) of T. denticola is known to dysregulate functions of host cells, including neutrophils. Neutrophils are key cells of the body's innate line of defense against pathogens in the gingival tissue, yet during periodontal disease, they are rendered ineffective. Regulation of phosphoinositides (PIPs), important cellular lipid metabolites, through appropriate lipid kinase and phosphatase activity are crucial to orchestrating neutrophil function and driving the immune response. Msp upsets the cellular PIP balance through inhibition of PI3K and activation of the phosphatase and tensin homolog (PTEN). Despite being one of T. denticola's most prominent virulence factors, the exact mechanism behind Msp's ability to limit neutrophil chemotaxis by manipulating the PI3K/PTEN lipid metabolism pathway is not well understood. We hypothesize that exposure to Msp, in isolated form or as a component of outer membrane vesicles, will limit neutrophils from responding to T. denticola, but also secondarily to other members of the “red complex”, promoting bacterial interaction and survival of the polymicrobial biofilm in the oral cavity. The overall objective of this project is to characterize how T. denticola impairs neutrophil function as a means to dysregulate the innate immune response, with the goal to identify the mechanism by which Msp interferes with PI3K signaling and phosphatase activation and characterize how the interaction of Msp with neutrophils supports the dysbiotic bacterial environment of severe periodontal disease. These goals will be accomplished by 1) determining the role of Msp in activating the lipid phosphatase SHIP1 and how Msp interacts with different isoforms of the lipid kinase PI3K to alter normal neutrophil signaling response and 2) characterizing the impact of T. denticola and Msp interaction with neutrophils to alter the ability of neutrophils to respond to other pathogens. This work will fill a gap in knowledge of the pathogenicity of T. denticola and its role in driving the manipulation of the neutrophil response in polymicrobial infections. Furthermore, the mentoring and training plan outlined in this proposal will aid in the attainment of the professional skills necessary to develop a successful independent academic research program in the future.