Genetic Mechanisms in Borrelia burgdorferi Pathogenesis

伯氏疏螺旋体发病机制的遗传机制

• 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
• 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

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）：莱姆病的病因学药Borrelia Burgdorferi是美国最常见的节肢动物传染剂，并在持续感染的患者中有大量发病率。 B. burgdorferi可以有效地定居哺乳动物和节肢动物宿主，因此，必须迅速调节基因表达以适应这些不同的环境。尽管我们知道某些改变了B. burgdorferi中基因表达的分子信号，但我们仍然对在该病原体中如何调节潜在的毒力决定因素如何了解。在过去的资金期间，我们表征了一种调节蛋白，该蛋白指定为BOSR，该蛋白参与了B. burgdorferi中的氧化应激反应。最近，我们发现与BOSR，BB0646和BB0648相关的两个基因共享了一个转录本，因此包含操纵子。这些基因分别编码出口脂肪酶（BB0646）和丝氨酸/苏氨酸激酶（BB0648），我们建议这与B. burgdorferi的氧化应激反应有关。中心假设是BOSR以及链接的基因BB0646和BB0648协调了一种重要的自适应反应，以感知细胞的氧化还原状态。为了解决这一假设，我们提出以下特定目的：（1）在传染性B. burgdorferi中表征BOSR操纵子。有效的假设是BOSR及其侧翼基因BB0646和BB0648对细胞的氧化还原状态做出了适当的反应，以抵抗节肢动物血液中产生的有毒氧化化合物或哺乳动物哺乳动物的先天免疫反应。我们尚未能够评估BOSR在传染性分离株中的作用，这大概是因为BOSR调节了必需基因。在这里，我们将使用最近开发的严格调节的诱导系统来在传染性B. burgdorferi中产生一个有条件的突变体。 （2）评估条件突变体的感染性不足和BOSR调节基因的敲除。工作假设是，由BOSR调节的基因是与氧化应激和感染性有关的生理重要过程所必需的。 （3）确定BOSR介导的调节的机制。工作假设是，BOSR通过氧化和金属结合改变了其调节活性，这改变了其对目标序列的亲和力。 （4）解密BB0646和BB0648在B. burgdorferi发病机理中的作用。我们的工作假设是，这两种基因产物都通过修饰多不饱和脂质底物并分别协调对氧化应激的全局反应，参与宿主适应。来自这些研究的信息将提供有关B. burgdorferi如何通过BOSR，BB0646和BB0648适应宿主氧化还原状态的洞察力，并将有助于确定随后的反应如何与这种重要病原体的疾病潜力有关。公共卫生相关性：莱姆病的病因学推动者Borrelia Burgdorferi是美国最常见的节肢动物传染剂，因此是一个重要的公共卫生问题。本文所描述的研究旨在解决B. burgdorferi在宿主介导的氧化防御措施的背景下如何能够适应tick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。