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: 10565957
• 负责人: Chunhao Chris Li
• 金额: $ 47.32万
• 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/10565957
• 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; 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; Shapes; Site; Solid; Structure; Surface; Swimming; Syphilis; Systemic infection; Ticks; Tissues; Virulence; Virulence Factors; Viscosity; cell motility; disorder prevention; empowerment; 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.

总结 莱姆病细菌伯氏疏螺旋体（Bb）是高度能动的，可以穿越复杂的环境内 哺乳动物和节肢动物宿主在其传染周期。本申请的中心假设是， Bb的运动性和趋化性构成了一个独特的范例，并在宿主-载体循环中发挥关键作用 如在疾病过程中，包括侵入、传播、组织嗜性和免疫逃避。在过去 在两个资助周期中，我们揭示了Bb运动性和趋化性的几个独特方面;然而， 在疾病过程中的分子机制和确切作用仍然是未知的。建立在我们的 以前的研究结果，本次更新旨在通过解决三个关键问题来填补这一知识空白：（1）Bb如何 控制鞭毛的不对称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 周质鞭毛（PF）不对称，以便运行：前PF逆时针旋转，后PF旋转， PF顺时针旋转。如果没有不对称旋转，细胞就会变形。这是一个标志性的特点， 然而，其潜在的分子机制仍然难以捉摸。Aim 1旨在解决这一问题 通过确定FliG 1的功能和结构来解决长期存在的难题，FliG 1是一种非经典的鞭毛马达开关 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是否进化出群集运动以促进其入侵性和毒性？在动物流行周期中， 有几次，Bb在高粘性的凝胶状环境中游泳，如哺乳动物的真皮组织和 蜱肠基膜，这是让人想起的环境中，细菌群，一种形式的 允许细菌在固体和半固体表面上爬行的运动。据推测，BB 进化出成群运动来增强其侵略性。目标2计划阐明 群集运动及其在Bb致病性中的作用，使用遗传学，生物化学， 结构生物学和体内动物模型沿着活体成像。(3)CheA 1是否控制Bb毒力 如果是的话，又是如何做到的呢？bb进化出独特的趋化性以适应其独特的运动性和地方性周期，例如， 其基因组编码多种趋化蛋白，如两种CheA组氨酸激酶（HK）：CheA 1和CheA 2。一 长期存在的问题是为什么Bb需要多种趋化蛋白。CheA 2是Bb所必需的，而CheA 1不是 趋化性CheA 1的作用仍然未知。有趣的是，我们最近发现Bb需要CheA 1 Bb在小鼠体内血行播散及几个关键毒力因子表达在此基础上， 结果，目的3阐明CheA 1在Bb致病中的作用及其分子机制， 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运动和趋化性以及它们在细胞内的确切作用。 莱姆病的发病机制。此外，要获得的基本知识是非常有影响力的，很可能 也有助于理解其他致病螺旋体的这些过程。