Quorum sensing regulation of bacterial development

项目摘要 细菌利用称为群体感应的细胞间信号系统进行交流， 基因表达对种群密度和组成变化的反应。群体感应控制 有利于群体适应和生存的行为，包括生物膜形成，运动， 生物发光以及毒素的产生和分泌。更全面地了解细胞-细胞 信号调节毒力和影响细菌在其环境生态位可能导致的发展， 调节群体感应以减轻发病机制的抗微生物分子。尽管取得了进展， 阐明群体信号输入，相对较少的是知道的输出-转录 控制细菌群体行为和发育的调节程序。建议的目标 研究是确定细菌如何使用群体感应信号来控制毒力基因的表达， 弧菌作为细菌群体感应系统和相关病原体建立模型。在弧菌属中，LuxR 是群体感应基因和毒力的主要转录因子和保守的核心调节因子。 以前的工作确定了重要的和高度保守的生物化学，生物物理和遗传特征， LuxR和控制基因表达的弧菌群体信号系统。然而，群体感应的影响 甚至在密切相关的弧菌菌株之间也存在差异， 不被理解。拟议的研究将扩大这些发现，以检查基因调控， LuxR在机械层面上，然后更广泛地将这些信息与保护和影响联系起来 群体信号网络的一部分。首先，拟议的研究将确定 染色体的空间组织和LuxR调节之间的联系， 发现类核结构蛋白影响几种弧菌群体感应基因的表达 物种第二，更广泛地研究来自“自我”（群体感应自诱导物）的信号的影响。 和“其他”（环境），群体感应基因表达将在单细胞和群体中进行评估- 广泛的水平响应于自诱导物信号传导和营养可用性的变化。拟议 微流控技术、细胞培养和宿主感染实验与比较基因组学相结合， 群体感应信号和弧菌适应环境和宿主信号之间的联系。三是 货车凯塞尔实验室最近开发了噻吩磺酰胺抑制剂，可以特异性阻断LuxR蛋白功能 在弧菌细菌中。这些分子是指导我们理解LuxR功能的关键工具， 潜在治疗化合物的结构-活性建模和抑制剂设计。总体而言，拟议的 这项研究将为理解群体信号及其如何影响细菌提供关键的基础数据。 致病机制，有助于弧菌病疾病治疗的未来进展。

Project Summary Bacteria communicate using the cell-cell signaling system called quorum sensing to collectively alter gene expression in response to changes in population density and composition. Quorum sensing controls behaviors that benefit the group for adaption and survival, including biofilm formation, motility, bioluminescence, and toxin production and secretion. A more comprehensive understanding of how cell-cell signaling regulates virulence and impacts bacteria in their environmental niches can lead to the development of anti-microbial molecules that modulate quorum sensing to mitigate pathogenesis. Despite advances in elucidating the quorum signaling inputs, comparatively less is known about the output – the transcriptional regulation program that controls group behaviors and development in bacteria. The objective of the proposed research is to define how bacteria use quorum sensing signaling to control virulence gene expression, using Vibrio bacteria as established quorum sensing model systems and relevant pathogens. In Vibrio species, LuxR is the master transcription factor and the conserved core regulator of quorum sensing genes and virulence. Previous work identified important and highly conserved biochemical, biophysical, and genetic features of LuxR and Vibrio quorum signaling systems that govern gene expression. Yet, the influence of quorum sensing on numerous developmental pathways varies even among closely related Vibrio strains through means that are not understood. The proposed research will expand upon these findings to examine gene regulation by LuxR at the mechanistic level and then more broadly connect this information to the conservation and impact of quorum signaling networks across Vibrio species. First, the proposed research will determine the connections between spatial organization of the chromosome and LuxR regulation based on established findings that nucleoid structuring proteins impinge on quorum sensing gene expression in several Vibrio species. Second, to more broadly examine the influence of signals from “self” (quorum sensing autoinducers) and “other” (environment), quorum sensing gene expression will be assessed at the single-cell and population- wide level in response to variations in autoinducer signaling and nutrient availability. The proposed microfluidics, cell culture, and host infection experiments combined with comparative genomics will provide key links between quorum sensing signaling and Vibrio adaptation to environmental and host signals. Third, the van Kessel lab recently developed thiophenesulfonamide inhibitors that specifically block LuxR protein function in Vibrio bacteria. These molecules are key tools that will guide our understanding of LuxR function and inform structure-activity modeling and inhibitor design for potential therapeutic compounds. Collectively, the proposed research will provide fundamental data critical to understanding quorum signaling and how it impacts bacterial pathogenesis to contribute to future advances in vibriosis disease treatment.