Genetic Mechanisms in Borrelia burgdorferi Pathogenesis

伯氏疏螺旋体发病机制的遗传机制

基本信息

批准号：
7589384
负责人：
JON T SKARE
金额：
$ 36.28万
依托单位：
TEXAS A&M UNIVERSITY HEALTH SCIENCE CTR
依托单位国家：
美国
项目类别：
财政年份：
1999
资助国家：
美国
起止时间：
1999-04-01 至 2014-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7589384
关键词：
Address Affect Arthropod Vectors Arthropods Avidity Bacteria Binding Biochemical Biology Blood Borrelia Borrelia burgdorferi Borrelia oxidative stress regulator Case Study Cells Centers for Disease Control and Prevention (U.S.)Development Disease Drug Metabolic Detoxication Emerging Communicable Diseases Environment Essential Genes Funding Gene Expression Genes Genetic Goals Homeostasis Immune response In Vitro Infectious Agent Isopropyl Thiogalactoside Knock-out Knowledge Life Cycle Stages Link Lipase Lyme Disease Mammals Mediating Metals Modeling Modification Molecular Molecular Genetics Morbidity - disease rate Operon Order Spirochaetales Organism Oxidation-Reduction Oxidative Stress Pathogenesis Patients Phospholipids Physiological Physiology Process Protein-Serine-Threonine Kinases Proteins Public Health Reactive Oxygen Species Regulation Relative (related person)Research Personnel Role Signal Transduction Staging Structural Models System Temperature Testing Ticks Transcript United States Virulence Virulent Work acyl group biological adaptation to stress combat design expectation genetic analysis genetic regulatory protein genome sequencing innovation insight mutant oxidation pathogen pathogenic bacteria polyunsaturated fat promoter public health relevance response trafficking transmission process vector

项目摘要

DESCRIPTION (provided by applicant): Borrelia burgdorferi, the etiologic agent of Lyme disease, is the most common arthropod- borne infectious agent in the United States, and contributes to a significant amount of morbidity in persistently infected patients. B. burgdorferi is effective at colonizing both mammalian and arthropod hosts and, as such, must modulate gene expression quickly to adapt to these different environments. Although we know some of the molecular signals that alter gene expression in B. burgdorferi, we still understand little regarding how potential virulence determinants are regulated in this pathogen. In the past funding period, we have characterized a regulatory protein, designated BosR, which is involved in regulating the oxidative stress response in B. burgdorferi. Recently, we found that two genes linked to bosR, bb0646 and bb0648, share a transcript and thus comprise an operon. These genes encode for an exported lipase (bb0646) and a serine/threonine kinase (bb0648), respectively, which we suggest are involved in the oxidative stress response in B. burgdorferi. The central hypothesis is that BosR, and the linked genes bb0646 and bb0648, coordinate an important adaptive response that senses the redox status of the cell. To address this hypothesis, we propose the following Specific Aims: (1) Characterize the bosR operon in infectious B. burgdorferi. The working hypothesis is that bosR and its flanking genes, bb0646 and bb0648, respond appropriately to the redox status of the cell to combat toxic oxidizing compounds generated during the arthropod blood meal or the mammalian innate immune response. We have not yet been able to evaluate the role of BosR in infectious isolates, presumably since bosR regulates essential genes. Here we will use a recently developed tightly regulated inducible system to generate a conditional mutant in bosR in infectious B. burgdorferi; (2) Assess the infectivity deficit in conditional mutants and knockouts in BosR-regulated genes. The working hypothesis is that genes regulated by BosR are required for physiologically important processes related to oxidative stress and infectivity; (3) Determine the mechanism of BosR-mediated regulation. The working hypothesis is that BosR alters its regulatory activity via oxidation and metal binding, which changes its avidity for target sequences; and (4) Decipher the role of BB0646 and BB0648 in B. burgdorferi pathogenesis. Our working hypothesis is that both of these gene products are involved in host adaptation by modifying polyunsaturated lipid substrates and coordinating a global response to oxidative stress, respectively. The information from these studies will provide insight into how B. burgdorferi adapts to the redox status of the host via BosR, BB0646, and BB0648, and will help to determine how the ensuing response relates to the disease potential of this important pathogen. PUBLIC HEALTH RELEVANCE: Borrelia burgdorferi, the etiologic agent of Lyme disease, is the most common arthropod-borne infectious agent in the United States, and thus is an important Public Health issue. The studies described herein are designed to address how B. burgdorferi is able to adapt to both ticks and mammals, in the context of host mediated oxidation defenses, and how this adaptive response affects the ability of this bacterium to persist within the environment and cause disease.

描述（由申请人提供）：伯氏疏螺旋体（Borrelia burgdorferi）是莱姆病的病原体，是美国最常见的节肢动物传播的传染原，导致持续感染患者的大量发病。伯氏疏螺旋体能够有效地定植哺乳动物和节肢动物宿主，因此必须快速调节基因表达以适应这些不同的环境。尽管我们知道一些改变伯氏疏螺旋体基因表达的分子信号，但我们仍然对这种病原体中潜在毒力决定因素的调节知之甚少。在过去的资助期间，我们鉴定了一种名为 BosR 的调节蛋白，它参与调节伯氏疏螺旋体的氧化应激反应。最近，我们发现与 bosR 连锁的两个基因 bb0646 和 bb0648 共享一个转录本，因此包含一个操纵子。这些基因分别编码输出脂肪酶 (bb0646) 和丝氨酸/苏氨酸激酶 (bb0648)，我们认为它们参与伯氏疏螺旋体的氧化应激反应。核心假设是 BosR 以及相关基因 bb0646 和 bb0648 协调重要的适应性反应，感知细胞的氧化还原状态。为了解决这一假设，我们提出以下具体目标：（1）表征传染性伯氏疏螺旋体中的 bosR 操纵子。工作假设是 bosR 及其侧翼基因 bb0646 和 bb0648 对细胞的氧化还原状态做出适当的反应，以对抗节肢动物吸血或哺乳动物先天免疫反应期间产生的有毒氧化化合物。我们尚未能够评估 BosR 在感染性分离株中的作用，大概是因为 bosR 调节必需基因。在这里，我们将使用最近开发的严格调控的诱导系统在传染性伯氏疏螺旋体的 bosR 中产生条件突变体； (2) 评估条件突变体和 BosR 调节基因敲除的感染性缺陷。工作假设是，受 BosR 调节的基因是与氧化应激和感染性相关的重要生理过程所必需的； (3)确定BosR介导的调节机制。工作假设是 BosR 通过氧化和金属结合改变其调节活性，从而改变其对靶序列的亲和力； (4)破译BB0646和BB0648在伯氏疏螺旋体发病机制中的作用。我们的工作假设是，这两种基因产物分别通过修饰多不饱和脂质底物和协调对氧化应激的整体反应来参与宿主适应。这些研究的信息将深入了解伯氏疏螺旋体如何通过 BosR、BB0646 和 BB0648 适应宿主的氧化还原状态，并将有助于确定随后的反应与这种重要病原体的疾病潜力之间的关系。公共卫生相关性：伯氏疏螺旋体是莱姆病的病原体，是美国最常见的节肢动物传播的传染源，因此是一个重要的公共卫生问题。本文描述的研究旨在解决伯氏疏螺旋体如何在宿主介导的氧化防御的背景下适应蜱和哺乳动物，以及这种适应性反应如何影响该细菌在环境中持续存在并引起疾病的能力。