Cyclic di-GMP-dependent regulation of metabolism and virulence in Borrelia burgdorferi

 描述(申请人提供)：莱姆病是美国报告最多的媒介传播疾病。伯氏疏螺旋体(BB)是一种专性致病螺旋体，通过扁虱叮咬传播。Bb是如何维持在哺乳动物和壁虱之间的地方性循环中的，人们对此知之甚少；然而，这种理解对于开发创新的方法来扰乱壁虱-哺乳动物-壁虱的自然循环至关重要。我们和其他人已经确定了一个两组分的信号转导系统HK1-Rrp1，它对于壁虱的BB生存是必不可少的。Rrp1是一种具有二鸟苷环化酶(DGC)活性的反应调节因子，可产生环状二聚体GMP(c-di-GMP)，这是一种新的细菌第二信使，控制着运动的单细胞生活方式和固定的多细胞生活方式(生物膜)之间的切换。我们发现，c-di-GMP介导的信号通过调节GLP操纵子的转录来控制从葡萄糖到甘油的分解代谢转换，GLP操纵子的转录用于甘油的运输和利用，而甘油的运输和利用对硬蜱中螺旋体的生存至关重要。此外，我们发现c-di-GMP结合效应蛋白Plza也控制着GLP的表达和多种毒力因子的合成。我们假设，由于基因组较小和简化的调控体系，BB使用相同的c-di-GMP效应器蛋白Plza，或与Plza相互作用的蛋白质，以协调参与哺乳动物到扁虱转变的不同过程(运动性、分解代谢、毒力)。为了检验这一假说并理解 为了在哺乳动物向节肢动物宿主的转变中传递c-di-GMP信号，我们制定了以下具体目标：(1)阐明c-di-GMP结合蛋白Plza对BB中甘油代谢和毒力的调节机制；(2)鉴定和鉴定BB中新的c-di-GMP结合效应蛋白，并探讨它们在扁虱生存中的作用。结果 将揭示哺乳动物向节肢动物宿主转变的新过程、新的c-di-GMP效应蛋白和新的c-di-GMP信号范例。

 DESCRIPTION (provided by applicant): Lyme disease is the most reported vector-borne disease in the United States. The causative agent, Borrelia burgdorferi (Bb), is an obligate pathogenic spirochete that is transmitted via a tick bite. How Bb is maintained in its enzootic cycle between mammals and ticks is poorly understood; yet, this understanding is critical for developing innovative approaches to disrupt the tick-mammal-tick natural cycle. We and others have identified a two-component signal transduction system, Hk1-Rrp1, that is essential for Bb survival in the tick. Rrp1is a response regulator possessing diguanylate cyclase (DGC) activity that produces cyclic dimeric GMP (c-di-GMP), a new bacterial second messenger that controls the switch between the motile, single-cellular lifestyle and the sessile, multicellular lifestyle (biofilms). We discovered that c-di-GMP-mediated signaling controls a catabolic switch from glucose to glycerol upon the transition from the mammal to the tick, by regulating the transcription of the glp operon for glycerol transport and utilization which are critical for spirochete survival in ticks. Further, we found that the c-di-GMP-binding effector protein PlzA, previously known to influence Bb motility, also controls glp expression as well as synthesis of multiple virulence factors. We hypothesize that, because of the small genome and streamlined regulatory repertoire, Bb employs the same c-di-GMP effector protein, PlzA, or a protein that interacts with PlzA, to coordinate diverse processes (motility, catabolism, virulence) that are involved in the mammal-to-tick transition. To test this hypothesis and to to understand the role of c-di-GMP signaling in the mammal-to-arthropod host transition, we have formulated the following Specific Aims: (1) Elucidate the mechanism of regulation of the glycerol metabolism and virulence by the c-di-GMP- binding protein PlzA in Bb; (2) Identify and characterize new c-di-GMP-binding effector proteins in Bb and interrogate their role in survival in the tick. Outcomes will uncover novel processes underlying the mammal-to-arthropod host transition, novel c-di-GMP effector proteins and new c-di-GMP signaling paradigm.