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: 10396603
• 负责人: Kirsten R Guckes
• 金额: $ 7.39万
• 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 2023-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10396603
• 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; Inflammatory Bowel Diseases; Knowledge; Lead; Light; Link; Mediating; Membrane; Microbe; Molecular; Needles; Organ; Outcome; Pathway interactions; Physiology; Population; Process; Production; Proliferating; Regulation; 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; gene regulatory network; host colonization; host-microbe interactions; improved; in vivo; 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 有必要制定策略，准确地从宿主中消除有害细菌，而不是广泛传播 对有益细菌种群的干扰。目前的策略，如抗生素治疗，往往会导致 导致生物失调的共生体种群组成的广泛变化，即丰度的不平衡 导致宿主健康受损的特定细菌。因此，这一未得到满足的需求有助于 持续存在与生物失调有关的疾病，如胃肠道疾病、传染性疾病 疾病和自身免疫性疾病。长期目标是增加对细菌间相互作用的理解 杀戮可以被用作促进健康的宿主-微生物联系和消除病原体的工具，从而导致 低风险的生物失调的治疗。这项建议的总体目标是确定机制 在宿主定植期间，细菌共生体之间的接触依赖性杀戮通过这种机制来调节。这 研究目标将利用短尾乌贼和乌贼之间建立的共生关系来实现 费氏弧菌。这种自然共生提供了一个研究细菌间杀戮的平台 简单易驯化的细菌共生体。紧密排列的费氏弧菌的生物发光群体聚集在一起 在被称为光器官的专门宿主结构中，种群组成可以直接 视觉化的。生物发光的表达由群体感应信号网络控制，该网络 允许种群内细菌细胞之间的通信。加在一起，鱿鱼弧菌的这些方面 共生提供了独特的机会来研究细菌间的杀戮以及这种调控如何影响 共生种群的组成。初步数据表明，群体感应调节杀戮。 通过VI型分泌系统(T6SS)。这项提议的核心假设是 在共生建立过程中，群体感应途径调控T6SS的表达。 这一中心假设将通过三个具体目标进行检验：1)确定群体感知如何影响T6SS 活性；2)确定T6SS结构成分是如何转录调控的；以及3)确定 T6SS表达对细菌适合性的影响目标1中的实验将评估群体感知 通过测试群体感应信号的不同组件在多大程度上影响T6SS活动 级联冲击T6SS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 T6SS的成分是通过研究转录激活子和一个 抑制者。目标3中的实验将确定调控联系之间的生物学意义 群体感应和T6SS体内寄主定植试验。拟议研究的结果 将提供对控制从宿主中消除细菌的机制的分子洞察，提供了一种 以期望的方式改变共生体成分的治疗策略的潜在途径。