Treponema denticola, complement regulatory proteins and periodontal disease

描述(申请人提供)：牙周病将影响大多数人在他们一生中的某个时刻，其经济影响是巨大的。牙周炎是宿主因素和正常菌群来源的多种微生物感染的综合结果。当每个物种的数量不平衡时，就会产生疾病。齿密螺旋体(TD)是牙周病的致病因素之一。我们证明TD通过11.5 kDa的TD脂蛋白FhbB与补体调节蛋白FHL-1结合。FhbB是唯一已知的由微生物病原体产生的蛋白质，它与FHL-1而不是FH特异结合。这种独特的结合特异性为TD与FHL-1结合的生物学基础提供了可能。FHL-1除了具有补体调节作用外，还具有重要的细胞黏附素和细胞扩散活性。一些依赖锚定的细胞系已被证明与FHL-1基质结合。这种结合通过FHL-1的RGD基序发生，该基序位于一个被称为短共识重复(SCR)4的结构域。FHL-1也通过其RGD黏附受体识别序列与组织的细胞外基质(ECM)相互作用。我们的假设是，齿状毛滴虫FhbB蛋白与细胞或细胞外基质锚定的FHL-1的结合在齿状毛滴虫致病的几个关键方面发挥着核心作用，包括黏附、生物被膜形成、组织渗透和免疫逃避。这些研究填补了齿状毛滴虫致病机制和FHL-1与口腔微生物区系结合的生物学作用研究的一个重要空白，并将促进我们对牙周病发生发展的分子机制的总体理解。这一应用的具体目的是：1)分析FhbB在人体宿主中的表达和产生，并评估牙周病期间抗FhbB抗体的反应；2：鉴定FhbB与FHL-1结合的分子决定因素；3)通过等位基因交换突变和互补，分析FhbB和FHL-1结合在齿状毛滴虫发病中的作用。一般描述：这项申请调查一种新的毒力机制所使用的牙周病病原体。这些分析的结果将允许开发新的牙周病预防和干预策略。

DESCRIPTION (provided by applicant): Periodontal disease will affect most individuals at some point in their life and its economic impact is enormous. Periodontitis results from a combination of host factors and a polymicrobial infection of normal flora origin. Disease results when an imbalance in numbers of each species develops. One contributor to periodontal disease is Treponema denticola (Td). We demonstrate that Td binds the complement regulatory protein, factor H like protein 1 (FHL-1) via an 11.5 kDa Td lipoprotein, designated, FhbB. FhbB is the only known protein produced by a microbial pathogen that specifically binds FHL-1 and not FH. This unique binding specificity provides possible insight into the biological rationale of FHL-1 binding by Td. In addition to its complement regulatory role, FHL-1 also has important cell adhesin and cell spreading activities. Several anchorage dependent cell lines have been demonstrated to bind to an FHL-1 matrix. The binding occurs through an RGD motif of FHL-1 that is located with a domain referred to as a short consensus repeat (SCR) 4. FHL-1 also interacts with the extracellular matrix (ECM) of tissue via this its RGD adhesion receptor recognition sequence. It is our hypothesis that the binding of cell or ECM anchored FHL-1 by the T. denticola FhbB protein plays a central role in several critical aspects of T. denticola pathogenesis including adherence, biofilm formation, tissue penetration and immune evasion. The studies proposed here fill an important niche in the study of T. denticola pathogenesis and of the biological role of FHL-1 binding by oral microflora and will advance our general understanding of the molecular mechanisms associated with the development and progression of periodontal disease. The Specific Aims of this application are: 1: Analysis of fhbB expression and production in the human host and assessment of the anti- FhbB antibody response during periodontal disease; 2: Identification of the molecular determinants of FhbB involved in FHL-1 binding; and 3) Analysis of the role of FhbB and FHL-1 binding in T. denticola pathogenesis through allelic exchange mutagenesis and complementation. General description: This application investigates a novel virulence mechanism employed by a causative agent of periodontal disease. The outcome of these analyses will allow for the development of new preventive and intervention strategies for periodontal disease.