Virulence Mechanisms of Multifunctional Borrelial Proteins

多功能疏螺旋体蛋白的毒力机制

基本信息

批准号：
10192642
负责人：
Brandon Lee Garcia
金额：
$ 73.11万
依托单位：
EAST CAROLINA UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-06-15 至 2025-05-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10192642
关键词：
Address Affinity Amino Acids Animal Model Antibodies Asia Bacteria Binding Biochemical Biological Assay Biophysics Borrelia Borrelia Infections Borrelia afzelii Borrelia burgdorferi Borrelia burgdorferi Group Borrelia garinii Borrelia miyamotoi Borrelia turicatae Classical Complement Pathway Clinical Communicable Diseases Complement Complement 1q Complement Activation Complement component C1r Complex Crystallization Cytolysis Data Disease Disease model Etiology Europe Event Experimental Models Family Genes Genetic Goals Hematogenous Homologous Gene Hot Spot Human Immune Immunity Immunocompetent Immunomodulators Impairment In Vitro Infection Lipoproteins Lyme Disease Lytic Measures Mediating Medical Microbe Microbiology Minor Modeling Molecular Mus Natural Immunity Nature Order Spirochaetales Orthologous Gene Pathogenesis Pathway interactions Pattern Recognition Peptide Hydrolases Phenotype Phylogenetic Analysis Play Proteins Reaction Relapsing Fever Reporting Resolution Role Serum Spirochaetales Infections Structure Surface Testing Ticks United States Vector-transmitted infectious disease Virulence X-Ray Crystallography arm biophysical techniques complement pathway complement system design experimental study human disease imaging approach immunoregulation in vitro activity in vivo in vivo Model in vivo imaging inhibitor/antagonist interdisciplinary approach lyme pathogenesis mouse model multidisciplinary mutant pathogen relapsing fever borrelia tick borne spirochete vector-borne vector-borne pathogen

项目摘要

PROJECT SUMMARY Spirochetes of the Borrelia genus are the cause of several prevalent vector-borne diseases. The most well-known pathogen from this group is Borrelia burgdorferi sensu stricto, which causes over 300,000 cases of Lyme disease in the United States each year. B. garinii and B. afzelii, which belong to the B. burgdorferi sensu lato complex, are the primary agent of Lyme disease in Europe and Asia. Borrelia spirochetes are also the etiological agent of the ancient human disease relapsing fever, as well as a newly recognized infectious condition called Borrelia miyamotoi disease. Lyme-associated, relapsing fever-associated, and B. miyamotoi spirochetes have differing lifecycles and their infections are accompanied by distinct clinical presentations. However, each of these pathogens are known to encode multifunctional surface-expressed lipoproteins that interact with vertebrate host molecules. Among these proteins are a small arsenal of immunomodulators that specifically target and inactivate a primary arm of innate immunity known as the complement system. We have recently reported two independent lines of evidence that support the hypothesis that one of these pathways, known as the classical pathway, is important in controlling B. burgdorferi infections. First, we have shown that mice deficient in the pattern recognition molecule of the classical pathway, C1q, are significantly more susceptible to B. burgdorferi infection. Secondly, we have shown that the lipoprotein B. burgdorferi BBK32 is a high-affinity inhibitor of the initiating protease of the classical pathway, C1r. In Aim 1 of this project we seek to understand the C1r inhibitory activity of BBK32 sensu lato proteins at the molecular level. In Aim 2 we will determine the immunomodulatory roles and virulence contribution of three BBK32 orthologues known as FbpA, FbpB, and FbpC which are found uniquely in relapsing fever and B. miyamotoi spirochetes. In Aim 3 we will delineate the role of C1r inhibition in borrelial pathogenesis using in vivo models of disease. To achieve this, we propose a multi-disciplinary strategy that employs x-ray crystallography, biophysical approaches, and complement functional assays to pinpoint key ‘hot-spot’ residues on BBK32 that give rise to its potent anti-C1r activity. These data will inform the design of bbk32 mutants which will be used in mouse infectivity studies to connect structural features of BBK32, at the amino-acid level, to an in vivo phenotype. Parallel studies will use genetic deletion mutants of fbp genes from the relapsing fever- associated spirochetes B. turicatae and B. hermsii. These studies will be paired with experimental models of Lyme and relapsing fever borrelioses using C1r-/- mice to better understand the role of the classical pathway initiating protease in the control of borrelial infections. By addressing fundamental questions of how medically important Borrelia spirochetes recognize and evade host immunity, the studies proposed here stand to have a broad and significant impact on the field of bacterial pathogenesis.

项目概要疏螺旋体属的螺旋体是几种流行的媒介传播疾病的原因。该组中著名的病原体是严格伯氏疏螺旋体 (Borrelia burgdorferi sensu stricto)，它导致超过 300,000 例病例美国每年都会出现莱姆病 B. garinii 和 B. afzelii，它们都属于伯氏疏螺旋体 (B. burgdorferi sensu)。拉托复合体是欧洲和亚洲莱姆病的主要病原体，也是螺旋体。古代人类疾病回归热的病原体，以及新发现的传染病称为宫本疏螺旋体病、回归热相关病和宫本疏螺旋体病。螺旋体具有不同的生命周期，其感染伴有不同的临床表现。然而，已知这些病原体中的每一种都编码多功能表面表达的脂蛋白，这些蛋白质中有一小部分免疫调节剂与脊椎动物宿主分子相互作用。专门针对并灭活先天免疫的主要臂，即补体系统。最近报道了两条独立的证据，支持这些途径之一的假设，被称为经典途径，对于控制伯氏疏螺旋体感染非常重要。首先，我们已经证明了这一点。缺乏经典途径模式识别分子 C1q 的小鼠，易受伯氏疏螺旋体感染其次，我们已经证明脂蛋白伯氏疏螺旋体 BBK32 是一种经典途径起始蛋白酶 C1r 的高亲和力抑制剂。在该项目的目标 1 中，我们试图了解 BBK32 感性乳蛋白的 C1r 抑制活性在目标 2 中，我们将确定三种病毒的免疫调节作用和毒力贡献。 BBK32 直向同源物称为 FbpA、FbpB 和 FbpC，仅在回归热和 B. 在目标 3 中，我们将描述 C1r 抑制在疏螺旋体发病机制中的作用。为了实现这一目标，我们提出了一种采用 X 射线的多学科策略。晶体学、生物物理方法和补充功能测定，以查明关键的“热点”残留物这些数据将为 bbk32 突变体的设计提供信息。将用于小鼠感染性研究，将 BBK32 在氨基酸水平上的结构特征与体内表型的平行研究将使用来自回归热的 fbp 基因的遗传缺失突变体。相关螺旋体 B. turicatae 和 B. Hermsii 的实验模型将与这些研究配对。使用 C1r-/- 小鼠研究莱姆病和回归热疏螺旋体病，以更好地了解经典途径的作用通过解决医学上如何启动蛋白酶来控制疏螺旋体感染。重要的疏螺旋体螺旋体识别并逃避宿主免疫，这里提出的研究表明，对细菌发病机制领域产生广泛而重大的影响。