Oral Treponema Surface Proteins: Host Cell Interactions

 描述(申请人提供)：这项研究的目标是表征齿密螺旋体(TD)表面蛋白在这种人类口腔螺旋体与宿主组织相互作用中的作用，从而深入了解这些微生物促进牙周病发生和发展的机制。我们专注于分析直接影响从组织中分离出来的细胞的TD蛋白复合体，这些组织包括牙周膜(PDL)，它包括牙齿和牙槽的牙槽骨连接：具体地说，是PRTP脂蛋白蛋白酶复合体(牙本质蛋白)和低聚MSP蛋白。我们的总体假设是牙菌素和MSP是牙周病TD细胞病变行为的主要贡献者。为了确定它们在微生物-宿主相互作用中的特定作用，我们的方法是利用纯化的天然和重组蛋白以及在这些外膜复合体的个别成分中携带明确突变的等基因TD菌株。我们将首先扩展我们正在进行的关于牙菌素在TD外膜中组装的研究。然后，为了进一步研究宿主细胞对TD攻击的反应，我们将(A)确定牙菌素诱导原-MMP2激活的机制，以及(B)表征TD攻击导致的PDL细胞中依赖于MMP2的纤维连接蛋白断裂。这个项目将检验这样的假设，即牙本质蛋白是一种效应蛋白，其活性导致放大的“下游”信号效应，这在体内可能是显著的。我们的研究团队拥有螺旋体分子生物学、细胞外基质生物学和炎症性疾病的细胞病理学方面的专业知识，在进行这些研究方面处于独特的地位。该项目的完成将有助于了解螺旋体分子生物学的基本知识，并有助于了解慢性感染(如牙周病)中微生物与宿主的相互作用。

 DESCRIPTION (provided by applicant): The goal of this research is to characterize the role of Treponema denticola (Td) surface proteins in interaction of this human oral spirochete with host tissue, thereby gaining insight into mechanisms by which these organisms contribute to initiation and progression of periodontal disease. We focus on analysis of Td protein complexes that directly affect cells isolated from tissue comprising the periodontal ligament (PDL) that comprises the junction between the tooth and the alveolar bone of the tooth socket: specifically the PrtP lipoprotein protease complex (dentilisin) and the oligomeric Msp protein. Our overall hypothesis is that dentilisin and Msp are major contributors to Td cytopathic behavior in periodontal disease. To characterize their specific roles in microbe-host interactions, our approach is to utilize purified native and recombinant proteins as well as isogenic Td strains carrying defined mutations in individual components of these outer membrane complexes. We will first extend our ongoing studies characterizing dentilisin assembly in the Td outer membrane. Then, to further studies of host cell responses to Td challenge, we will (A) determine the mechanism of dentilisin-induced activation of pro-MMP-2 and (B) characterize MMP-2-dependent fibronectin fragmentation resulting from Td challenge of PDL cells. This project will test the hypothesis that dentilisin is an effector protein whose activity results in magnified "downstream" signaling effects that are likely to be significant in vivo. Our research team is uniquely positioned to conduct these studies, with combined expertise in spirochete molecular biology, extracellular matrix biology and cytopathology of inflammatory diseases. Completion of this project will contribute to both basic knowledge of spirochete molecular biology and to understanding of microbe-host interactions in chronic infections such as periodontal diseases.