The Heart of OspC as a Borrelia burgdorferi Adhesin

作为伯氏疏螺旋体粘附素的 OspC 核心

基本信息

批准号：
7785567
负责人：
Jenifer L Coburn
金额：
$ 19万
依托单位：
MEDICAL COLLEGE OF WISCONSIN
依托单位国家：
美国
项目类别：
财政年份：
2010
资助国家：
美国
起止时间：
2010-03-01 至 2012-02-28
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7785567
关键词：
Adhesions Affect Alleles Amino Acids Animals Antibiotic Therapy Antibodies Bacteria Bacterial Adhesins Bacteriophages Binding Biochemical Bite Bladder Blood Borrelia Borrelia burgdorferi Buffers Cardiac Cell Culture Techniques Cell Surface Receptors Cell physiology Cells Charge Core Protein DBL Oncoprotein DNA Data Data Set Disaccharides Disease Endothelium Environment Epicardium Future Glycosaminoglycans Goals Harvest Health system Heart Human Human Cell Line Immune response Immune system In Vitro Infection Injection of therapeutic agent Inovirus Integrins Investigation Joints Laboratories Lead Libraries Life Ligands Light Lipoproteins Lyme Disease Mammalian Cell Mammals Measures Membrane Proteins Mus Mutate Myocardium Nature Nervous system structure Neurologic Order Spirochaetales Organism OspC protein Perfusion Phage Display Phase Polymers Process Protein Fragment Proteins Proteoglycan Recombinants Regulation Role Rosa Signal Transduction Site Site-Directed Mutagenesis Skin Staging Surface Tail Testing Therapeutic Ticks Time Tissues Veins Work base design epimerization extracellular in vitro activity in vivo insight interest mutant particle public health relevance receptor research study sulfation tool vector

项目摘要

DESCRIPTION (provided by applicant): Borrelia burgdorferi, the causative agent of Lyme disease, establishes persistent infection that can affect the joints, heart, skin, and nervous system. The ability of this spirochete to establish infection demands 1) dissemination from the site of inoculation by an infected tick, 2) adaptation to the mammalian environment, and 3) persistence despite the host immune response. Interactions with mammalian cells occur continually during each of these steps and phases of infection. Using a phage display selection in vitro, we showed that the B. burgdorferi outer membrane protein, P66, binds to the 3-chain integrins. In an in vivo phage display selection, we also showed that OspC serves as an adhesin to an unknown receptor in the endothelium in living mice. Phage clones bearing OspC sequences were the single group most highly selected in vivo, and most of the clones were selected in the heart. OspC is a protein of the Lyme disease Borrelia that is expressed as the bacteria move from tick to mammal, and was previously shown by another group to be critical for the earliest stages of infection of mice. A different group showed that a deficiency in OspC could be partially overcome in scid mice by over-expression of other lipoproteins. This work also revealed that OspC does appear to be essential for normal dissemination of the bacteria to the heart, the tissue in which our phage clones were most frequently selected. Our data are also consistent with previous work by a third group demonstrating that B. burgdorferi in the heart express higher levels of ospC than do the bacteria in other tissues tested. Our overall hypothesis is that the adhesin activity of OspC is important to its critical function in the life of B. burgdorferi. Based on our results as well as those of the three other groups, we will test two facets of this hypothesis in this proposal. The first is that OspC recognizes a receptor localized in regions of the heart colonized by B. burgdorferi. The second is that specific conserved amino acids are required for adhesin activity and normal function in establishment of disseminated infection in mice. B. burgdorferi strains that do and do not express OspC will be tested for adhesion activity in cell culture and targeting of the heart, and particular regions therein, in mice. Additional strains expressing mutated alleles of OspC will be generated and tested using the same approaches. In this set of experiments we propose to employ our unique tools to further define, at the biochemical level, the role of OspC in B. burgdorferi infection. We anticipate that this work may enable the design of therapeutic approaches to halt dissemination of B. burgdorferi after the tick bite even in unvaccinated people and animals. PUBLIC HEALTH RELEVANCE: Lyme disease is now 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 due to neurologic, cardiac, and rheumatologic manifestations of disease. We propose to delve into how Borrelia burgdorferi interacts with the heart in a mammalian host. We will focus on one B. burgdorferi protein, OspC, which is essential for the bacteria to cause the normal disseminated infection in mice. Our overall goal is to understand how OspC recognition of host cell molecules allows B. burgdorferi to overcome host barriers to the establishment of persistent, disseminated infection, which could eventually lead to strategies that will help the host immune system clear the organism as adjuncts to antibiotic therapy.

描述（由申请人提供）：莱姆病的致病药物Borrelia Burgdorferi建立了持续的感染，可以影响关节，心脏，皮肤和神经系统。这种螺旋体建立感染的能力要求1）通过感染壁虱从接种部位传播，2）尽管宿主免疫反应，但仍适应哺乳动物环境，3）持久性。在每个感染的步骤和阶段，与哺乳动物细胞的相互作用不断发生。使用噬菌体显示体外选择，我们表明b。brgdorferi外膜蛋白P66与3链整合素结合。在体内噬菌体显示选择中，我们还表明，OSPC用作活小鼠内皮中未知受体的粘附蛋白。带有OSPC序列的噬菌体克隆是体内最高度选择的单组，并且大多数克隆是在心脏中选择的。 OSPC是莱姆病渗流菌的一种蛋白质，其表达为细菌从tick虫转向哺乳动物，并以前被另一组显示，对于小鼠感染的最早阶段至关重要。另一组表明，通过过度表达其他脂蛋白，在SCID小鼠中可能会部分克服OSPC的缺乏。这项工作还表明，OSPC似乎对于将细菌的正常传播到心脏，最常见的噬菌体克隆的组织是必不可少的。我们的数据还与第三组先前的工作一致，该研究表明，心脏中的伯氏芽孢杆菌表现出比其他测试的组织中的细菌更高的OSPC水平。我们的总体假设是，OSPC的粘附素活性对其在B. burgdorferi的生活中的关键功能很重要。根据我们的结果以及其他三个小组的结果，我们将在该提案中检验该假设的两个方面。首先是OSPC识别出由B. burgdorferi殖民的心脏区域中的受体。第二个是在小鼠中建立弥散性感染中粘附素活性和正常功能所必需的特定保守氨基酸。 B. B. burgdorferi菌株将在小鼠中测试和不表达OSPC的OSPC的粘附活性和心脏及其特定区域的粘附活性。将使用相同的方法生成和测试表达OSPC突变等位基因的其他菌株。在这组实验中，我们建议采用我们独特的工具在生物化学层面进一步定义OSPC在B. burgdorferi感染中的作用。我们预计，这项工作可能会在tick咬伤后，即使在未接种疫苗的人和动物中，也可以设计治疗方法来停止B. burgdorferi的传播。公共卫生相关性：莱姆病现在是北半球最普遍的媒介传播疾病，并且由于疾病的神经系统，心脏和风湿病表现而普遍存在卫生系统的重大负担。我们建议深入研究Borrelia Burgdorferi在哺乳动物宿主中与心脏相互作用的方式。我们将专注于一种B. burgdorferi蛋白OSPC，这对于细菌引起小鼠正常传播感染至关重要。我们的总体目标是了解OSPC对宿主细胞分子的识别如何允许B. burgdorferi克服宿主的障碍，以建立持续的，传播的感染，最终可能导致策略，这些策略将有助于宿主免疫系统将生物体清除为抗生素治疗的辅助物质。