Identification of essential factors contributing to vector colonization and transmission of relapsing fever spirochetes

回归热螺旋体媒介定植和传播的重要因素的鉴定

• 批准号: 10112814
• 负责人: Job E Lopez
• 金额: $ 39.63万
• 依托单位: BAYLOR COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-03-01 至 2023-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10112814
• 关键词: Address; Area; Arthropods; Black-legged Tick; Blood; Borrelia turicatae; Candidate Disease Gene; Child; Childhood; Chromosome Mapping; Code; Comparative Genomic Analysis; Data; Data Set; Defect; Development; Disease; Environment; Essential Genes; Event; Exhibits; Fever; Gene Expression; Generations; Genes; Genetic; Genome; Genomic approach; Genomics; Goals; Health; Human body; Image; In Vitro; Infection; Infectious Diseases Research; Interruption; Knowledge; Laboratories; Life Cycle Stages; Location; Malaria; Mammals; Measures; Mediating; Membrane Proteins; Midgut; Mind; Mission; Modeling; Molecular; Morbidity - disease rate; Mus; Mutagenesis; National Institute of Allergy and Infectious Disease; Order Spirochaetales; Ornithodoros; Pathogenesis; Pattern; Pediculus humanus humanus; Plasmids; Population; Preventive vaccine; Process; Production; Proteins; Proteome; Public Health; Publishing; Quantitative Reverse Transcriptase PCR; Relapsing Fever; Risk; Role; Salivary Glands; Series; Site-Directed Mutagenesis; Structure; Surface; System; Tick-Borne Relapsing Fever; Ticks; Tuberculosis; United States National Institutes of Health; Vector-transmitted infectious disease; World Health Organization; Zoonoses; biophysical analysis; comparative; comparative genomics; diarrheal disease; functional genomics; gene product; human disease; improved; mortality; mutant; neglect; novel; pathogen; pathogenic microbe; prevent; tick bite; tick feeding; transcriptomics; transmission process; vector; vector tick; vector transmission

Project Summary Understanding the life cycle of a pathogen within different natural environments is a poorly evolved area of infectious disease research. Tick-borne relapsing fever (RF) spirochetes are one such pathogen that have adapted to colonize arthropods and mammalian blood. When a tick imbibes an infectious bloodmeal, spi- rochetes enter the midgut. Within ~ 2 weeks a population subsequently migrates and colonizes the salivary glands. However, the molecular events facilitating vector colonization and subsequent transmission to the mammalian host remain unclear. Consequently, delineating the intricacies of the life cycle of RF spirochetes is particularly relevant to public health. Limitations in RF spirochete genomics, transcriptomics, and genetics have been addressed by develop- ing the Borrelia turicatae-Ornithodoros turicata model. Utilizing a functional genomic approach, two important observations were made that this proposal builds upon: 1) after 220 generations, B. turicatae losses genes es- sential in vector colonization and/or establishing mammalian infection; 2) the 150 kb linear megaplasmid (lp150) is likely important for vector colonization and transmission. A 36 kb locus toward the 3' end of the plas- mid contains a series of genes that coded for surface proteins that are up-regulated in the tick vector compared to infected mammalian blood. The central hypothesis of this application is that there are subsets of B. turicatae genes essential in midgut and salivary gland colonization and establishing early mammalian infection. The fol- lowing aims are purposed: Aim 1: Identify genes that are essential in the tick-mammalian transmission cycle by comparative ge- nomics, and define temporal expression and protein production of B. turicatae genes localized in the 36 kb locus. The objective is to quantify the expression of genes in the 36 kb locus during the pathogens life cycle in the tick vector, and coincide the findings with protein production. Also, a comparative genomic analysis between a wild type spirochetes and noncolonizing/noninfectious strains will identify likely essential genes. Aim 2: Identify and characterize genes essential in vector colonization and transmission by mutagene- sis, imaging, and structural and biophysical analyses. The objective is to generate and evaluate B. tu- ricatae mutants, to identify defects in tick-mediated transmission to mice. The significance of these genes in the tick-mammalian transmission cycle will be further verified by site directed mutagenesis and structural and biophysical analyses. With the surface proteome of RF spirochetes serving essential roles in pathogenesis, these findings will guide strategies to interrupt the pathogen's life cycle in the tick and mammal. The results will be broadly appli- cable to Old and New World species, and address NIAID's mission to better understand and prevent disease.

项目概要 了解病原体在不同自然环境中的生命周期是一个很糟糕的进化过程 传染病研究领域。蜱传回归热 (RF) 螺旋体就是这样一种病原体 已经适应了节肢动物和哺乳动物血液的定殖。当蜱虫吸入具有传染性的血粉时， 罗切特进入中肠。在约 2 周内，种群随后迁移并在唾液中定居 腺体。然而，分子事件促进载体定植并随后传播到 哺乳动物宿主仍不清楚。因此，描述 RF 螺旋体生命周期的复杂性是 尤其与公共卫生相关。 RF 螺旋体基因组学、转录组学和遗传学的局限性已通过开发解决 建立Borrelia turicatae-Ornithodoros turicata 模型。利用功能基因组方法，两个重要的 根据观察结果，该提议建立在：1) 220 代之后，B. turicatae 丢失了基因 es- 对于载体定植和/或建立哺乳动物感染至关重要； 2) 150 kb 线性巨质粒 (lp150) 可能对于载体定植和传播很重要。一个 36 kb 的位点，位于质粒的 3' 端 mid 包含一系列编码表面蛋白的基因，与蜱载体相比，这些表面蛋白的表达上调 感染哺乳动物的血液。本申请的中心假设是 B. turicatae 存在子集 中肠和唾液腺定植和建立早期哺乳动物感染所必需的基因。接下来的 降低目标的目的是： 目标 1：通过比较基因鉴定蜱-哺乳动物传播周期中必需的基因 组学，并定义位于 B. turicatae 基因的时间表达和蛋白质生产 36 kb 基因座。目的是量化病原体生命期间 36 kb 基因座中的基因表达 蜱虫载体中的循环，并且这些发现与蛋白质生产相一致。此外，比较基因组分析 野生型螺旋体和非定植/非感染性菌株之间的比较将鉴定出可能的必需基因。 目标 2：通过诱变鉴定和表征载体定植和传播所必需的基因 sis、成像、结构和生物物理分析。目标是生成并评估 B. tu- ricatae 突变体，以识别蜱介导的向小鼠传播的缺陷。这些基因的意义 蜱-哺乳动物传播周期将通过定点诱变和结构和 生物物理分析。 由于 RF 螺旋体的表面蛋白质组在发病机制中发挥重要作用，这些发现将 指导中断蜱虫和哺乳动物中病原体生命周期的策略。研究结果将被广泛应用 电缆连接新旧世界物种，并履行 NIAID 更好地了解和预防疾病的使命。