Understanding Unique Aspects of Motility and Chemotaxis in Borrelia burgdorferi

了解伯氏疏螺旋体的运动性和趋化性的独特方面

• 批准号: 10446214
• 负责人: Chunhao Chris Li
• 金额: $ 48.7万
• 依托单位: VIRGINIA COMMONWEALTH UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-09-19 至 2027-01-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10446214
• 关键词: Achievement; Address; Agar; Animal Model; Anterior; Arthropods; Bacillus subtilis; Bacteria; Bacteria sigma factor KatF protein; Basement membrane; Biochemistry; Biology; Borrelia burgdorferi; Cell Shape; Cells; Cellular Morphology; Chemotaxis; Complex; Cryo-electron tomography; Crystallography; Data; Dermis; Disease; Environment; Flagella; Funding; Gel; Genetic; Genome; Geometry; Goals; Hematogenous; Homologous Gene; Human; Immune Evasion; Infection; Interdisciplinary Study; Invaded; Journals; Knowledge; Laboratories; Lead; Leptospirosis; Lyme Disease; Molecular; Molecular Analysis; Motor; Movement; Mus; Order Spirochaetales; Organ; OspC protein; Paper; Pathogenesis; Pathogenicity; Peer Review; Play; Process; Proteins; Publishing; Role; Rotation; Running; Site; Solid; Structure; Surface; Swimming; Syphilis; Systemic infection; Ticks; Tissues; Virulence; Virulence Factors; cell motility; disorder prevention; enzootic; genetic approach; in vivo; insight; interdisciplinary approach; intravital imaging; lyme pathogenesis; mutant; periplasm; protein-histidine kinase; structural biology; success; tick transmission; tissue tropism; transcriptome sequencing; transmission process; vector

SUMMARY Lyme disease bacterium Borrelia burgdorferi (Bb) is highly motile and can traverse complex environments inside mammalian and arthropod hosts during its infectious cycle. The central hypothesis of this application is that the motility and chemotaxis of Bb constitute a distinct paradigm and play a pivotal role in the host-vector cycle as well as in the disease process, including invasion, dissemination, tissue tropism, and immune evasion. During the last two funding cycles, we revealed several unique aspects of Bb motility and chemotaxis; however, their underlying molecular mechanisms and precise roles in the disease process remain largely unknown. Building upon our previous findings, this renewal aims to fill this knowledge gap by addressing three key questions: (1) How does Bb control asymmetrical flagellar rotation? Due to its unique cell shape and geometry, Bb must rotate its bipolar periplasmic flagella (PF) asymmetrically in order to run: the anterior PF rotates counterclockwise, and the posterior PF rotates clockwise. Without asymmetrical rotation, the cells become distorted. This is a hallmark feature of spirochete motility; however, its underlying molecular mechanism remains elusive. Aim 1 seeks to unravel this longstanding conundrum by determining the function and structure of FliG1, a noncanonical flagellar motor switch protein, using an integrative approach of genetics, biochemistry, cryo-electron tomography, and crystallography. (2) Has Bb evolved swarming motility to facilitate its invasiveness and virulence? During the enzootic cycle, on several occasions, Bb swims in highly viscous gel-like environments, such as mammalian dermis tissue and the tick-gut basement membrane, which are reminiscent of the environments in which bacteria swarm, a form of movement that allows bacteria to crawl over solid and semi-solid surfaces. It has been speculated that Bb has evolved swarming motility to empower its invasiveness. Aim 2 plans to delineate the underlying mechanism of swarming motility and its role in the pathogenicity of Bb, using a comprehensive approach of genetics, biochemistry, structural biology, and in vivo animal models along with intravital imaging. (3) Does CheA1 control Bb virulence and, if so, how? Bb has evolved unique chemotaxis to accommodate its distinct motility and enzootic cycle, e.g., its genome encodes multiple chemotaxis proteins such as two CheA histidine kinases (HK): CheA1 and CheA2. A longstanding question is why Bb needs multiple chemotaxis proteins. CheA2, but not CheA1, is essential for Bb chemotaxis. The role of CheA1 remains unknown. Interestingly, we recently found that CheA1 is required for Bb hematogenous dissemination in mice and expression of several key virulence factors of Bb. Building upon these results, Aim 3 proposes to elucidate the role and underlying molecular mechanism of CheA1 in Bb pathogenicity, using a multidisciplinary approach of genetics, biochemistry, RNA-seq, and animal models. Achievement of these aims will lead to a better understanding of Bb motility and chemotaxis as well as their precise roles in the pathogenesis of Lyme disease. Moreover, the fundamental knowledge to be gained is highly impactful and likely to aid understanding of these processes in other pathogenic spirochetes as well.

概括 莱姆病细菌Borrelia burgdorferi（BB）是高度运动的，可以遍历内部的复杂环境 哺乳动物和节肢动物在其传染性周期中宿主。该应用的中心假设是 BB的运动性和趋化性构成了独特的范式，并且在宿主矢量周期中也起着关键作用 就像在疾病过程中一样，包括入侵，传播，组织往往和免疫逃避。最后 两个资金周期，我们揭示了BB运动性和趋化性的几个独特方面。但是，它们的基础 分子机制和疾病过程中的精确作用在很大程度上未知。建立在我们的基础上 以前的发现，这种续约旨在通过解决三个关键问题来填补这一知识差距：（1）BB如何 控制不对称的鞭毛旋转？由于其独特的细胞形状和几何形状，BB必须旋转其双极 为了运行，无质鞭毛（PF）不对称：前PF逆时针旋转，后部旋转 PF顺时针旋转。没有不对称旋转，细胞会变形。这是一个标志性的功能 螺旋体运动；但是，其潜在的分子机制仍然难以捉摸。 AIM 1试图解开此事 通过确定Flig1的功能和结构（一种非规范的鞭毛运动开关）长期存在的难题 蛋白质，使用遗传学，生物化学，冷冻电子断层扫描和晶体学的综合方法。 （2）BB是否发展了蜂群的运动性以促进其侵入性和毒力？在enzootic循环中， 在几次中，BB在高粘性凝胶样环境中游泳，例如哺乳动物真皮组织和 tick ut地下室膜，让人联想到细菌群的环境 运动可以使细菌在固体和半固体表面上爬行。据推测BB有 不断发展的运动能力赋予其侵入性。 AIM 2计划描述的基本机制 使用遗传学，生物化学，生物化学的全面方法，蜂拥而至的运动及其在BB致病性中的作用 结构生物学和体内动物模型以及浸润成像。 （3）CHEA1控制BB毒力 而且，如果是的话？ BB发展了独特的趋化性，以适应其独特的运动性和enzootic循环，例如 它的基因组编码多种趋化蛋白，例如两个CHEA组氨酸激酶（HK）：CHEA1和CHEA2。一个 长期以来的问题是为什么BB需要多种趋化蛋白。 CHEA2，但不是CHEA1，对于BB至关重要 趋化性。 CHEA1的作用仍然未知。有趣的是，我们最近发现BB需要CHEA1 小鼠中血源性传播和BB的几种关键毒力因子的表达。基于这些 结果，AIM 3提议阐明CHEA1在BB致病性中的作用和潜在分子机制， 使用遗传学，生物化学，RNA-Seq和动物模型的多学科方法。实现这些 目的将导致更好地理解BB的运动性和趋化性及其在其中的精确作用 莱姆病的发病机理。此外，要获得的基本知识具有很高的影响力，并且很可能 也有助于理解其他病原螺旋体中的这些过程。