Cyclic di-GMP Second Messenger Signaling in the Tickborne Relapsing Fever Spirochete, Borrelia turicatae

项目总结/摘要 引起回归热的媒介传播的螺旋体通过蜱或人类传播给人类。 体虱尽管100多年前就确定了回归热的病原体， 存在关于这些细菌的致病机理的信息。复发性发热在发展中国家更常见 蜱传回归热（TBRF）也发生在美国的一些地区， 作为结核分枝杆菌出血热螺旋体载体的蜱种是地方性的。在自然的地方性流行周期中， 螺旋体存在于节肢动物媒介和脊椎动物中发现的两个不同的小生境中。公 莱姆病螺旋体必须经历全局基因表达的显著变化， 以适应这两种不同的环境。环二聚鸟苷一磷酸（c-di-GMP）是一种 重要的第二信使分子，在伯氏疏螺旋体的地方流行周期中起关键作用， 但其在TBRF螺旋体中的调节作用尚未研究。在本提案中，我们将测试 c-di-GMP信号通路在促进TBRF螺旋体适应不同宿主中的作用 在细菌自然生命周期中遇到的环境。虽然我们预期c-di-GMP依赖 信号对TBRF螺旋体的地方流行周期很重要，也有显着差异 莱姆病疏螺旋体和TBRF疏螺旋体的发病机制和载体生物学之间的联系， 预期在TBRF螺旋体感染和载体定殖期间c-di-GMP的相对贡献 可能是独一无二的。为了解决这个问题，我们已经灭活了c-di-GMP中的各个组件 调控系统的低传代，毒性分离的B。turiclavia。在具体目标1中，这些表型 将使用实验B评价突变体。turicatae-O. turicata传播/感染模型来定义 c-di-GMP信号通路在B的地方流行周期中的重要性。turiclavia。在具体目标2中， 我们将使用这些突变体来确定c-di-GMP信号系统对B的影响。环球旅游 基因表达和蛋白质生产。这些目标将提供有关监管的关键知识， 控制B的网络。在传播和感染过程中的尿路适应。的分子特征 单个c-di-GMP信号传导组分，它们在毒力调节中的特定作用， 毒力决定因素将是未来R 01资助提案的重点。调节因子和毒力因子 本项目中确定的潜在靶点代表了未来治疗干预和/或 可以开发TBRF的诊断方法。

PROJECT SUMMARY/ABSTRACT The vector-borne spirochetes that cause relapsing fever are transmitted to humans by either ticks or human body lice. Despite identification of the etiological agents of relapsing fever over 100 years ago, very little information exists regarding their pathogenesis of these bacteria. Relapsing fever is more common in developing countries, but tickborne relapsing fever (TBRF) also occurs in areas of the U.S. where Ixodes and Ornithodoros species of ticks, the vectors for TBRF spirochetes, are endemic. During their natural enzootic cycle, vector-borne spirochetes exist in two distinct niches found within the arthropod vector and the vertebrate. It is well established that Lyme disease spirochetes must undergo significant changes in global gene expression to allow them to adapt to these two diverse environments. Cyclic dimeric guanosine monophosphate (c-di-GMP) is an important second messenger molecule that plays a key role during the enzootic cycle of Borrelia burgdorferi, but its regulatory contribution in TBRF spirochetes has not been investigated. In this proposal, we will test the role of the c-di-GMP signaling pathway in promoting adaptation of TBRF spirochetes to the different host environments encountered during the bacterial natural lifecycle. While we expect c-di-GMP-dependent signaling to be important for the enzootic cycle of TBRF spirochetes, there are also significant differences between the pathogenesis and vector biology of Lyme disease Borrelia and TBRF Borrelia that lead us to anticipate that the relative contribution of c-di-GMP during TBRF spirochete infection and vector colonization could be unique. To being addressing this, we have inactivated individual components in the c-di-GMP regulatory system in a low-passage, virulent isolate of B. turicatae. In Specific Aim 1, the phenotypes of these mutants will be evaluated using the experimental B. turicatae-O. turicata transmission/infection model to define the importance of the c-di-GMP signaling pathway during the enzootic cycle of B. turicatae. In Specific Aim 2, we will use these mutants to determine the influence of the c-di-GMP signaling system on B. turicatae global gene expression and protein production. These aims will provide critical knowledge regarding the regulatory networks that control B. turicatae adaptation during transmission and infection. Molecular characterization of the individual c-di-GMP signaling components, their specific roles in virulence regulation, and potential virulence determinants will be the focus of future R01 grant proposals. Regulators and virulence factors identified in this project represent potential targets against which future therapeutic interventions and/or diagnostics for TBRF could be developed.