Impact of quorum sensing on type VI secretion activities during symbiosis establishment

共生建立过程中群体感应对 VI 型分泌活动的影响

• 批准号: 10232074
• 负责人: Kirsten R Guckes
• 金额: $ 7.05万
• 依托单位: PENNSYLVANIA STATE UNIVERSITY, THE
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-05-01 至 2023-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10232074
• 关键词: Address; Affect; Animals; Antibiotic Therapy; Autoimmune Diseases; Bacteria; Bacterial Physiology; Biological; Biological Assay; Bioluminescence; Cells; Communicable Diseases; Communication; Data; Development; Disease; Euprymna scolopes; Foundations; Gastrointestinal Diseases; Genes; Genetic Transcription; Genotype; Goals; Growth; Habitats; Health; Human; Human Microbiome; Impairment; Knowledge; Lead; Light; Link; Mediating; Membrane; Microbe; Molecular; Needles; Organ; Outcome; Pathway interactions; Physiology; Population; Process; Production; Proliferating; Regulation; Regulator Genes; Research; Research Design; Risk; Signal Transduction; Signaling Molecule; Solid; Squid; Structure; Symbiosis; System; Systemic disease; Testing; Therapeutic; Toxin; Transcript; Transcription Coactivator; Transcriptional Regulation; Vibrio; Vibrio fischeri; bacterial fitness; cancer therapy; design; disorder risk; dysbiosis; experimental study; fitness; host colonization; host-microbe interactions; improved; in vivo; inflammatory disease of the intestine; insight; intercellular communication; microbial; microbiome composition; mutant; pathogen; prevent; programs; quorum sensing; response; small molecule; symbiont; tool; trait; transcription factor; weapons

Project Summary There is a need for strategies to precisely eliminate harmful bacteria from the host without widespread disruptions to the beneficial bacterial populations. Current strategies, such as antibiotic treatment often lead to broad changes to symbiont population compositions that lead to dysbiosis, i.e., an imbalance in the abundance of particular bacteria leading to compromised host health. Therefore, this unfulfilled need contributes to the continued persistence of diseases associated with dysbiosis, such as gastrointestinal disease, infectious disease, and autoimmune disorders. The long-term goal is to increase understanding of how inter-bacterial killing can be used as a tool promote healthy host-microbe associations and eliminate pathogens, leading to therapeutics with a low risk of dysbiosis. The overall objective of this proposal is to determine the mechanism by which contact-dependent killing between bacterial symbionts is regulated during host colonization. This research objective will be accomplished using the symbiosis established between the bobtail squid and bacterium Vibrio fischeri. This natural symbiosis provides a platform to study inter-bacterial killing within a simple, tractable bacterial symbiont. Bioluminescent populations of tightly packed V. fischeri cells assemble within a specialized host structure called the light organ, where the population composition can be directly visualized. Expression of bioluminescence is controlled by the quorum-sensing signaling network, which permits communication between bacterial cells within a population. Together, these aspects of the squid-vibrio symbiosis provide the unique opportunity to study inter-bacterial killing and how that regulation influences the composition of symbiotic populations. Preliminary data suggests that quorum sensing regulates killing between V. fischeri cells through the type VI secretion system (T6SS). The central hypothesis of this proposal is that the quorum-sensing pathway regulates T6SS expression in V. fischeri during symbiosis establishment. This central hypothesis will be tested via three specific aims: 1) determine how quorum sensing impacts T6SS activity; 2) determine how T6SS structural components are transcriptionally regulated; and 3) determine the impact of T6SS expression on bacterial fitness. The experiments in Aim 1 will evaluate how quorum sensing impacts T6SS activity by testing the extent to which different components of the quorum-sensing signaling cascade impact T6SS-mediated killing. The experiments proposed in Aim 2 will determine how a vital structural component of the T6SS is regulated by investigating co-regulation by a transcriptional activator and a repressor. The experiments in Aim 3 will determine the biological significance of the regulatory link between quorum sensing and the T6SS using in vivo host colonization assays. The outcomes of the proposed studies will provide molecular insight into a mechanism that controls elimination of bacteria from a host, providing a potential avenue for a therapeutic strategy to alter symbiont compositions in a desired manner.

项目摘要 需要一种策略来精确地从宿主中消除有害细菌，而不广泛传播。 破坏有益的细菌种群。目前的策略，如抗生素治疗，往往导致 导致生态失调的共生体种群组成的广泛变化，即，大量的不平衡 导致宿主健康受损。因此，这种未满足的需求有助于 与生态失调有关的疾病持续存在，如胃肠道疾病、传染病、 疾病和自身免疫性疾病。长期目标是增加对细菌间如何相互作用的理解。 杀灭可用作促进健康的宿主-微生物关联并消除病原体的工具， 生态失调风险低的治疗方法。本提案的总体目标是确定 在宿主定殖过程中，细菌共生体之间的接触依赖性杀伤被调节。这 研究目标将利用短尾鱿鱼和 费氏弧菌这种自然共生提供了一个平台，研究细菌间的杀伤在一个 简单易处理的细菌共生体紧密堆积的费氏弧菌细胞的生物发光群体聚集 在一个称为光器官的特殊宿主结构中，种群组成可以直接 可视化。生物发光的表达是由群体感应信号网络控制的， 允许群体内细菌细胞之间的交流。结合起来，乌贼弧菌的这些方面 共生提供了研究细菌间杀伤以及调节如何影响 共生种群的组成。初步数据表明，群体感应调节杀戮 V. fischeri细胞之间通过VI型分泌系统（T6 SS）。这项提议的核心假设是 在共生建立过程中，群体感应途径调节费氏弧菌中T6 SS的表达。 这个中心假设将通过三个具体目标进行测试：1）确定群体感应如何影响T6 SS 活性; 2）确定T6 SS结构组分如何被转录调节;和3）确定T6 SS结构组分的转录水平。 T6 SS表达对细菌适应性影响。目标1中的实验将评估群体感应如何 通过测试群体感应信号的不同成分在多大程度上影响T6 SS活动， 级联影响T6 SS介导的杀伤。目标2中提出的实验将确定一个重要的结构如何 T6 SS的组分通过研究转录激活因子和转录因子的共调节来调节。 阻遏物目标3中的实验将确定以下两个因素之间调节联系的生物学意义： 群体感应和T6 SS使用体内宿主定殖测定。拟议研究的结果 将为控制从宿主中消除细菌的机制提供分子见解， 以期望的方式改变共生体组成的治疗策略的潜在途径。