B.forsythus BsPA protein: role in virulence

超出提供的空间。福赛氏拟杆菌是一种革兰氏阴性厌氧菌，与牙周病的发病机制有关。尽管对这种生物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蛋白含有富含亮氨酸的重复基序家族(LRR)和免疫球蛋白超家族基序(Ig-SF)的同源序列。在体外，BSPA蛋白与细胞外基质成分纤维连接蛋白和纤维蛋白原结合，并与上皮细胞结合，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表达缺陷的福赛斯杆菌突变株，其与纤维连接蛋白、纤维蛋白原和上皮细胞的结合能力显著减弱。这些研究将解决这样的假设，即LRRs和IgSF结构域通过与特定的细胞受体结合而对宿主细胞的相互作用至关重要，而BSPA蛋白通过介导细菌定植和触发宿主细胞反应，如释放细胞因子和其他介质，在发病中发挥重要作用。实验设计将包括：(A)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(特定目标L a)，并调查由BspA结合引起的细胞内信号事件(目标L b)；(B)结合BspA蛋白的上皮细胞(目标2a)和单核细胞受体(目标2b)的生化特征；(C)通过在小鼠牙周病模型(目标3a)中的研究以及通过评估有牙周炎病史的患者对BSpA蛋白的宿主免疫反应(目标3b)来评估BSpA蛋白在体内的作用。这一发现将对确定BSPA蛋白的作用及其结构域在细菌发病中的潜在作用具有重要意义。从蛋白质组学的角度来看，这些研究对于确定在其他细菌蛋白中发现的LRR和LG样信号的作用也是至关重要的。从长远来看，了解BSPA介导的连翘杆菌致病的基本机制对于制定牙周病的干预策略是至关重要的。PERFORMANCESITE(========================================Section End===========================================

EXCEED THE SPACE PROVIDED. 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), as well as 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 also 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 thal 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: (a) studies to determine the specific BspA-domains involved in host cell (epithelial and monocytic cells) interactions (Specific Aim l a), and investigate intracellular signaling events resulting from BspA binding (Aim l b); (b) biochemical characterization of epithelial (Aim 2a) and monocyte receptors (Aim 2b) that bind BspA protein; and (c) 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 lg- 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. PERFORMANCESITE( ========================================Section End===========================================