Treponema denticola cytoskeletal filaments and oral infection

描述（申请人提供）：在口腔细菌性疾病的主要病原体中，密螺旋体是最具侵袭性的生物。各种口腔密螺旋体细菌种类有一个共同的细胞质结构，其组织结构与中间细丝相似。体外实验已经证明了这种结构在与口腔感染性相关的关键事件中的重要性。本研究的目的是破译密螺旋体中间样丝在体内致病性中的重要性和功能。长期目标是制定新的策略来对抗螺旋体细胞的侵袭性，同时保持健康的口腔微生物群。其基本原理是验证梅毒体繁殖（首先是局部的，然后是全身的定植、持续和传播）依赖于中间样细丝的假设。拟议的研究将侧重于在适当的动物模型中测试一种缺乏中间样细丝（cfpA敲除）的基因工程齿状舌菌突变体的致病性，以研究口腔感染。cfpA敲除突变体的感染性将在两种小鼠模型中进行测试。第一个小鼠模型研究了与牙髓感染相关的组织和骨损伤（目的1）。第二个小鼠模型测试牙周感染的致病性（目的2）。与cfpA敲除突变体一起，将使用野生型菌株（活的和福尔马林杀死的）作为对照，以及缺乏运动性的突变体来测试在定植步骤中活抗原呈献的效果。实验的定量终点是在牙髓模型中测量感染牙根的骨质流失，在牙周模型中测量牙髓-牙釉质交界处的牙槽骨嵴退缩。定性标准是与感染相关的炎症，在根管感染模型中通过感染牙齿中心平面的组织学来评估，在牙周感染模型中通过细胞因子的产生来评估。在牙周感染模型的情况下，另一个标准将是感染后口腔微生物群的改变。本研究将通过更全面地了解中间样丝在感染性中的作用、运动对密螺旋体持久性的重要性，并模拟与牙周病相关的生物膜种群变化，进一步了解牙周和牙髓感染中牙牙真菌的发病机制。为了调节口腔生物膜，临床医生需要新的策略来对抗牙周病。新的策略依赖于对微生物生物学的理解。为了限制骨质流失和其他损伤，在患者愈合过程中应促进适当的宿主反应和健康的天然生物膜。我们的策略是针对侵略性和侵入性病原体的关键功能实体，目标是消除引起损害的种群。

DESCRIPTION (provided by applicant): Among the key pathogens involved in oral bacterial diseases, Treponema denticola is the most invasive organism. The various oral Treponema bacterial species have in common a cytoplasmic structure with organizational similarities to intermediate filaments. In vitro experiments have demonstrated the importance of such structure in key events related to oral infectivity. The goal of this research is to decipher the importance and function of treponemal intermediate-like filaments in pathogenicity in vivo. The long-term goal is to develop new strategies to combat the invasive nature of treponemal cells, while maintaining a healthy oral microbiota. The rationale is to validate the hypothesis that treponemes propagation (colonization, persistence, and dissemination first local and then systemic) is dependent upon intermediate- like filaments. The proposed studies will focus on testing the pathogenicity of a genetically engineered T. denticola mutant deficient in intermediate-like filaments (cfpA knockout) in appropriate animal models to study oral infections. The infectivity of the cfpA knockout mutant will be tested in two mouse models. The first mouse model investigates the tissue and bone damage associated with an endodontic infection (Aim 1). The second mouse model tests the pathogenicity in a periodontal infection (Aim 2). In conjunction with the cfpA knockout mutant, the wild-type strain (live and formalin-killed) will be used as control, as well as a mutant deficient in motility to test the effect of live antigen presentation during the colonization step. The experimental quantitative endpoint is the measurement of bone loss at the root of the infected tooth in the endodontic model, and the recession of the alveolar bone crest from the cementoenamel junction in the periodontal model. A qualitative criterion is the inflammation associated with the infection, which is to be evaluated by histology of the center plane of the infected tooth in the endodontic infection model, and by cytokine production in the periodontal infection model. In the case of the periodontal infection model, an additional criterion will be the modification of the oral microbiota post-infection. This study will further our understanding of the pathogenesis of T. denticola in both periodontal and endodontic infections by providing a more complete understanding of the role of intermediate-like filaments in infectivity, the importance of motility for treponemes persistence, and model the biofilm population changes associated with periodontal disease. To allow the modulation of the oral biofilm, clinicians need new strategies to fight periodontal diseases. New strategies rely on an understanding of microbial biology. To limit bone loss and other damages, proper host responses and healthy natural biofilm should be promoted in the patient healing process. Our strategy is to target key functional entities of aggressive and invasive pathogens, with the goal of eliminating the damage- inducing population.