Comprehensive Analysis of Borrelia burgdorferi Adhesins

描述(申请人提供)：伯氏疏螺旋体是莱姆病的病原体，可持续感染，影响关节、心脏、皮肤和神经系统。这种螺旋体在哺乳动物宿主的不同部位传播和存活的能力表明，在感染过程中，与哺乳动物细胞和细胞外基质的相互作用持续发生。事实上，许多已知或推测的粘附素已被发现，这表明不同的黏附途径的协同作用使伯氏杆菌在其特有的多相和多系统感染过程中能够经历连续的步骤。不幸的是，我们目前知识中的一个重要缺口是缺乏任何机械信息来指导这个有吸引力的模型。这种缺乏洞察力的部分原因是，到目前为止发现的一些粘附素在结合活性上存在重叠，这一因素混淆了对任何单一黏附途径的直接分析。在此，我们建议在没有潜在冗余机制的情况下，对每个粘附素的性质和功能进行全面的体外和体内分析。为此，该应用程序汇集了三名首席调查人员，每个人都有独特的专业知识领域，以解决这一关键的知识差距。这三个实验室将采用最先进的方法，包括在非粘附性、高传代菌株背景下产生功能获得伯氏杆菌突变体并测试菌株的体外黏附活性(Aim 1，Leong实验室)，将所有功能获得突变体与亲本菌株在小鼠组织中的细菌负荷进行量化(Aim 2，Coburn实验室)，以及活体显微镜检查每种菌株与活体小鼠血管系统之间相互作用的性质(Aim 3，Chaconas实验室)。因此，该项目是对伯氏杆菌不同粘附素在机体建立免疫活性动物播散性感染能力中所起作用的首次系统研究。我们的长期目标是了解不同粘附素的生化活动如何共同发挥作用，以使伯氏杆菌克服宿主障碍，建立持续的传播性感染。随着莱姆病在北半球的流行继续扩大，无论是病例数量还是地理分布，这项工作可能会阐明伯氏杆菌如何在人类中引起莱姆病并持续存在于动物宿主中。这一创新的多重PI项目将拥有独特专业知识的团队聚集在一起，将允许对具有明确生化活性的大量伯氏杆菌蛋白质进行全面研究。这些蛋白质可能是作为疫苗候选或作为治疗干预的靶向开发的极佳候选者。 公共卫生相关性：莱姆病是北半球最流行的病媒传播疾病，在该病流行的地区对卫生系统造成重大负担。我们建议深入研究与哺乳动物组织成分结合的伯氏疏螺旋体蛋白是如何对细菌引起小鼠感染至关重要的。这一应用的三个主要研究人员共同组成了一个拥有独特专业知识的团队，将允许对大量具有独特生化活性的伯氏杆菌蛋白质进行全面研究，这些蛋白质可能是开发为疫苗候选或治疗干预目标的极佳候选者。

DESCRIPTION (provided by applicant): Borrelia burgdorferi, a causative agent of Lyme disease, establishes persistent infection that can affect the joints, heart, skin, and nervous system. The abilities of this spirochete to disseminate and persist in a variety of sites in the mammalian host indicate that interactions with mammalian cells and extracellular matrix occur continually during infection. In fact, many documented or putative adhesins have been identified, suggesting that the concerted action of diverse adhesion pathways enables B. burgdorferi to negotiate successive steps during its characteristic multiphasic and multisystemic infection. Unfortunately, an important gap in our current knowledge is the lack of any mechanistic information to inform this attractive model. This paucity of insight is due in part to the fact that some of the adhesins identified to date display an overlap in binding activities, a factor that confounds straightforward analysis of any single adhesion pathway. Here we propose a comprehensive in vitro and in vivo analysis of the properties and function of each adhesin in the absence of potentially redundant mechanisms. To this end, this application brings together three principal investigators, each with a unique area of expertise, to address this critical knowledge gap. The three laboratories will employ state of the art approaches, including generation of gain-of-function B. burgdorferi mutants in a non-adherent, high-passage strain background and testing of the strains for in vitro adhesion activities (Aim 1, Leong lab), quantification of bacterial burdens for all gain-of-function mutants in comparison to the parental strain in mouse tissues (Aim 2, Coburn lab), and intravital microscopic examination of the nature of the interaction between each of the strains and the vasculature in living mice (Aim 3, Chaconas lab). This project therefore constitutes the first systematic examination of the roles of the diverse adhesins of B. burgdorferi in the ability of the organism to establish disseminated infection in immunocompetent animals. Our long-term goal is to understand how the biochemical activities of different adhesins function together to allow B. burgdorferi to overcome host barriers to the establishment of persistent, disseminated infection. As Lyme disease prevalence continues to expand in the Northern hemisphere, in terms of both case numbers and geographic distribution, this work may illuminate how B. burgdorferi causes Lyme disease in humans and persists in its animal reservoirs. This innovative multiple PI project brings together teams with unique expertise that will allow comprehensive investigations of a large set of B. burgdorferi proteins with defined biochemical activities. These proteins may be excellent candidates for development as vaccine candidates or for targeting as therapeutic interventions. PUBLIC HEALTH RELEVANCE: Lyme disease is the most prevalent vector-borne illness in the northern hemisphere, and a significant burden on the health system in regions in which it is common. We propose to delve into how Borrelia burgdorferi proteins that bind to mammalian tissue components are critical for the bacteria to cause infection in mice. The three principal investigators of this application together are a team with unique expertise that will allow comprehensive investigations of a large array of B. burgdorferi proteins that have unique biochemical activities and may be excellent candidates for development as vaccine candidates or targeting for therapeutic interventions.