Redox Regulation of DksA-dependent Borrelia burgdorferi infectivity

项目总结 伯氏疏螺旋体是莱姆病的病原体，是美国莱姆病的主要病源 每年超过47.6万例。像其他媒介传播的病原体一样，伯氏杆菌必须克服广泛的变种。 在其感染周期中的环境应激在硬蜱属和各种哺乳动物宿主中。 伯氏杆菌面临的挑战包括pH、温度、渗透压、养分可获得性、 活性氧物种(ROS)和一氧化氮(NO)及其同系物[活性氮物种(RNS) (例如，NO、NO2·、N2O3和ONOO-)]。其中，温度和pH对伯氏杆菌毒力基因的影响 表现性和感染性是最好的特征。我们实验室以前发表的研究成果和 其他人已经证明，伯氏杆菌在生物学上遇到了大量的ROS和RN。 在其媒介硬蜱和哺乳动物宿主感染期间。我们还证明了半胱氨酸 参与基因调控、抗氧化防御和中枢代谢的蛋白质硫醇是ROS的靶标。 和RNS，尽管这些修饰对伯氏杆菌感染性的影响尚不确定。我们的 先前发表的研究表明，DNAK抑制蛋白(DksA)是基因表达的全球调节因子 在伯氏杆菌中，并协调在营养限制期的严格反应。我们现在有 初步数据支持DksA在调节毒力基因表达中的作用 肩部寄主和哺乳动物体内的感染循环。尽管如此，我们的知识仍有很大差距。 关于Dks A如何在其载体和哺乳动物宿主中感知变化以指导伯氏杆菌基因的表达。 在这个应用程序中，我们建议测试我们的中心假设，即Dks A感觉到壁虱携带的ROS/RN进行协调 伯氏杆菌完成其感染周期所需的转录反应。这项建议是 特别具有创新性，并将通过确定扁虱传播疾病的潜在机制来影响该领域 伯氏杆菌感知环境变化以调节基因表达的能力。由于这一地区 关于壁虱传播疾病的研究几乎没有被调查过，我们的发现无疑将为 实地开展工作，并通报未来预防扁虱传播感染的战略。

PROJECT SUMMARY Borrelia burgdorferi, the etiologic agent of Lyme disease, is a major source of illness in the United States with over 476,000 cases per year. Like other vector-borne pathogens, B. burgdorferi must overcome a wide variety of environmental stresses during its infectious cycle in ticks of the genus Ixodes, and various mammalian hosts. Among the challenges faced by B. burgdorferi are shifts in pH, temperature, osmolarity, nutrient availability, reactive oxygen species (ROS) along with nitric oxide (NO) and its congeners [reactive nitrogen species (RNS) (e.g., NO, NO2•, N2O3 and ONOO-)]. Of these, the roles of temperature and pH on B. burgdorferi virulence gene expression and infectivity have been the best characterized. Previously published work from our laboratory and others have demonstrated that B. burgdorferi encounters biologically significant amounts of ROS and RNS during infection of its tick vector Ixodes scapularis and mammalian hosts. We have also shown that cysteine thiols of proteins involved in gene regulation, antioxidant defenses, and central metabolism are targets of ROS and RNS, although the impact of these modifications on B. burgdorferi infectivity have yet to be determined. Our previously published work showed the DnaK suppressor protein (DksA) is a global regulator of gene expression in B. burgdorferi and coordinates the stringent response during periods of nutrient limitation. We now have preliminary data supporting a role for DksA in regulating virulence gene expression required for completion of its infectious cycle in I. scapularis and mammalian hosts. Despite this, there are substantial gaps in our knowledge about how DksA senses changes within its vector and mammalian hosts to direct B. burgdorferi gene expression. In this application, we propose to test our central hypothesis that DksA senses tick-borne ROS/RNS to coordinate the transcriptional responses of B. burgdorferi required for the completion of its infectious cycle. This proposal is particularly innovative and will impact the field of tick-borne diseases by determining the mechanisms underlying the ability of B. burgdorferi to sense changes in its environment to regulate gene expression. Since this area of research is virtually uninvestigated for tick-borne diseases, our findings will undoubtedly provide insight to the field and inform future strategies to prevent tick-borne infections.