B.forsythus BsPA protein: role in virulence

B.forsythus BsPA 蛋白：在毒力中的作用

• 批准号: 6999798
• 负责人: Ashu Sharma
• 金额: $ 26.83万
• 依托单位: STATE UNIVERSITY OF NEW YORK AT BUFFALO
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-04-01 至 2007-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6999798
• 关键词: B.forsythus; BsPA; protein; role; virulence

DESCRIPTION: Bacteroides forsythus is a Gram-negative oral anaerobe implicated in the development of periodontal disease pathogenesis. Although, very little is known about the virulence factors of this organism, based on our recent in vitro and in vivo studies, a surface-associated 98-kDa protein (BspA) has been suggested as a virulence factor. The BspA protein contains homologous sequences belonging to the leucine-rich repeat motif family (LRR), and to motifs belonging to the immunoglobulin superfamily (Ig-SF). In vitro, the BspA protein binds to extracellular matrix components fibronectin and fibrinogen, and to epithelial cells, and induces release of proinflammtory cytokines from monocytic cells. Further, a mutant of B. forsythus defective in BspA expression constructed in our laboratory has been found to be significantly attenuated in its ability to bind to fibronectin, fibrinogen, and epithelial cells. The studies proposed here will address the hypotheses that LRRs and IgSF domains are critical for host cell interactions via binding to specific cellular receptors, and that the BspA protein plays important roles in pathogenesis via mediating bacterial colonization and triggering of host cellular responses, such as release of cytokines and other mediators. The experimental design will include: 1) studies to determine the specific BspA-domains involved in host cell (epithelial and monocytic cells) interactions (Specific Aim 1a), and investigate intracellular signaling events resulting from BspA binding (Aim 1b); 2) biochemical characterization of epithelial (Aim 2a) and monocyte receptors (Aim 2b) that bind BspA protein; and 3) assessment of the in vivo role of BspA protein as judged by studies in a mouse model of periodontal disease (Aim 3a), and by evaluating the host immune response against the BspA protein in patients with a history of periodontitis (Aim 3b). The findings will be important in determining the roles of BspA protein, and the underlying contribution of its domains in bacterial pathogenesis. The studies will also be critical from a proteomic standpoint in defining the roles of LRR and Ig-like signatures found in other bacterial proteins in general. In the long term, understanding the basic mechanisms of the BspA-mediated pathogenesis of B. forsythus will be vital in developing intervention strategies against periodontal disease.

描述：福赛斯拟杆菌是一种革兰氏阴性口腔厌氧菌，与牙周病发病机制的发展有关。尽管人们对这种生物体的毒力因子知之甚少，但根据我们最近的体外和体内研究，表面相关的 98-kDa 蛋白 (BspA) 已被认为是一种毒力因子。 BspA 蛋白含有属于富含亮氨酸重复基序家族 (LRR) 的同源序列，以及属于免疫球蛋白超家族 (Ig-SF) 的基序。在体外，BspA 蛋白与细胞外基质成分纤连蛋白和纤维蛋白原以及上皮细胞结合，并诱导单核细胞释放促炎细胞因子。此外，我们实验室构建的 BspA 表达缺陷的连翘 B. forsythus 突变体被发现其与纤连蛋白、纤维蛋白原和上皮细胞结合的能力显着减弱。这里提出的研究将提出以下假设：LRR 和 IgSF 结构域通过与特定细胞受体结合而对宿主细胞相互作用至关重要，并且 BspA 蛋白通过介导细菌定植和触发宿主细胞反应（例如释放）在发病机制中发挥重要作用细胞因子和其他介质。实验设计将包括：1) 研究确定参与宿主细胞（上皮细胞和单核细胞）相互作用的特定 BspA 结构域（具体目标 1a），并研究 BspA 结合产生的细胞内信号转导事件（目标 1b）； 2) 结合 BspA 蛋白的上皮 (Aim 2a) 和单核细胞受体 (Aim 2b) 的生化特征； 3) 通过对牙周病小鼠模型的研究（目标 3a）以及评估有牙周炎病史的患者针对 BspA 蛋白的宿主免疫反应来评估 BspA 蛋白的体内作用（目标 3b） 。这些发现对于确定 BspA 蛋白的作用及其结构域在细菌发病机制中的潜在贡献非常重要。从蛋白质组学的角度来看，这些研究对于定义其他细菌蛋白中发现的 LRR 和 Ig 样特征的作用也至关重要。从长远来看，了解 BspA 介导的福赛斯芽孢杆菌发病机制的基本机制对于制定针对牙周病的干预策略至关重要。