Campylobacter jejuni cyclic-di-GMP signaling and pathogenesis

摘要 空肠弯曲杆菌是引起美国和世界各地胃肠炎的主要细菌。 全世界每年有1.4亿例空肠弯曲菌胃肠炎病例，美国每年有130万例。 这种感染每年导致3万人死亡，主要是不发达国家的5岁儿童。 大多数空肠弯曲菌病是散发性的，由受污染的食物(尤其是家禽)和 暴露在环境水域中。部分空肠弯曲菌感染(~1/1000)导致格林-巴利综合征的发生。 巴雷综合征是世界上导致急性瘫痪的主要原因。尽管患病率很高，但 空肠弯曲杆菌病和近40年的研究，空肠弯曲菌致病的机制 仍然没有完全被理解和严重不足的研究。 许多细菌，包括人类病原体，使用第二信使c-di-GMP(c-di-GMP)来 调节代谢和毒力相关特性。通常，c-di-GMP是由二鸟苷盐合成的。 含有GGDEF结构域的环酶(DGC)，并被带有EAL或HD-的磷酸二酯酶(PDE)降解- GYP域。累积的c-di-GMP与介导下游调控的不同受体结合 C-di-GMP的作用。细菌的c-di-GMP信号网络可能相当复杂；有些细菌有几十个 DGC和PDE被认为整合了大量上游信号并调节蛋白质表达或 相应的活动。相比之下，预测的空肠弯曲菌c-di-GMP网络由单一的DGC组成，胆汁- 电阻响应调节器CbrR。这是对空肠弯曲菌中c-di-GMP信号的首次研究。 总体假设：空肠弯曲菌使用c-di-GMP信号来调节胆汁抵抗、运动/趋化， 和生物被膜的形成，通过发散的二鸟苷环化酶反应调节子CbrR。 我们建议对空肠弯曲菌中c-di-GMP介导的基因调控进行详细的研究，重点是 二鸟苷环化酶CbrR控制胆汁抵抗表达的机制 运动性/趋化性和生物膜形成。我们将使用遗传、生化和RNA序列的组合 实现这两个具体目标中概述的目标的方法：目标1)确定CbrR-Produced的作用 C-di-GMP在空肠弯曲菌胆汁抵抗、运动/趋化和生物膜形成中的作用；目的2)确定 受CbrR调控的基因。总而言之，这些将为我们中断的长期目标奠定基础 这一新的信号网络和阻断宿主间的传播和人类的发病机制。

ABSTRACT Campylobacter jejuni is a primary bacterial cause of gastroenteritis in the United States and throughout the world, with 140 million cases worldwide and 1.3 million cases of C. jejuni gastroenteritis in the U.S. each year. This infection leads to >30,000 deaths annually, primarily in children <5 years old in underdeveloped countries. Most cases of C. jejuni disease are sporadic and result from contaminated food (especially poultry) and exposure to environmental waters. Some C. jejuni infections (~1/1,000) lead to the development of Guillain- Barré Syndrome, the leading cause of acute paralysis in the world. Despite the high prevalence of Campylobacter disease and nearly 40 years of research, the mechanisms by which C. jejuni causes disease remain incompletely understood and severely understudied. Numerous bacteria, including human pathogens, use the second messenger cyclic-di-GMP (c-di-GMP) to regulate metabolic and virulence-related characteristics. Typically, c-di-GMP is synthesized by diguanylate cyclases (DGCs) containing GGDEF domains, and degraded by phosphodiesterases (PDEs) with EAL or HD- GYP domains. Accumulated c-di-GMP binds to diverse receptors that mediate the downstream regulatory effects of c-di-GMP. Bacterial c-di-GMP signaling networks can be quite complex; some bacteria have dozens of DGCs and PDEs that are thought to integrate numerous upstream signals and adjust protein expression or activity accordingly. In contrast, the predicted C. jejuni c-di-GMP network consists of a single DGC, the bile- resistance response regulator CbrR. This is the first study of c-di-GMP signaling in C. jejuni. Overall Hypothesis: C. jejuni uses c-di-GMP signaling to modulate bile resistance, motility/chemotaxis, and biofilm formation, by means of the divergent diguanylate cyclase response regulator CbrR. We propose a detailed study of c-di-GMP-mediated gene regulation in C. jejuni, focusing on the mechanism by which the diguanylate cyclase CbrR controls the expression of bile resistance, motility/chemotaxis, and biofilm formation. We will use a combination of genetic, biochemical, and RNA-Seq approaches to achieve the goals outlined in these two specific aims: Aim 1) Define the role of CbrR-produced c-di-GMP in C. jejuni bile resistance, motility/chemotaxis, and biofilm formation; and Aim 2) Determine the genes that are regulated by CbrR. Together, these will lay the groundwork for our long-term goal of interrupting this novel signaling network and interrupting inter-host transmission and pathogenesis in humans.