Host-associated biofilm formation and dispersal mechanisms

宿主相关生物膜的形成和扩散机制

• 批准号: 10798991
• 负责人: Karen L Visick
• 金额: $ 23.79万
• 依托单位: LOYOLA UNIVERSITY CHICAGO
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-05-01 至 2025-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10798991
• 关键词: Affect; Animal Model; Animals; Antibiotics; Bacteria; Calcium; Calcium oxide; Cells; Characteristics; Communicable Diseases; Communities; Cytoprotection; Distal; Environment; Environmental Protection; Euprymna scolopes; Event; Genes; Genetic Transcription; Host Defense; Human; Individual; Infection; Laboratory culture; Location; Microbial Biofilms; Modeling; Mutation; Nitric Oxide; Nosocomial Infections; Organ; Outcome; Phosphotransferases; Physiological; Polysaccharides; Post-Transcriptional Regulation; Process; Production; Signal Transduction; Site; Squid; Surface; Symbiosis; Testing; Therapeutic; Tissues; Vibrio fischeri; Visual; Visualization; Work; antimicrobial; cell community; genomic locus; host-associated biofilms; human disease; inhibitor; insight; macromolecule; medical implant; microbiome; posttranscriptional; response; sensor

Abstract Bacteria can form multi-cellular communities in which individual cells are protected from environmental insults such as antibiotics by virtue of being [1] encased in a protective matrix comprised of polysaccharides and other macromolecules and [2] physiologically distinct from free-living, planktonic cells. Biofilm formation enhances the ability of bacteria to colonize surfaces, including host tissues and abiotic surfaces such as medical implants, and seeds subsequent infections at distal locations through dispersal processes. As a result of these characteristics, bacteria in biofilms are responsible for the majority of hospital-acquired infections and thus understanding how biofilms form and disperse from such biofilms is critical. Although numerous animal models of biofilm formation have been developed, few, if any, permit visual examination of biofilm formation and dispersal events as well as a quantitative analysis of subsequent colonization outcomes. One such robust model, however, can be found in the Vibrio fischeri-squid (Euprymna scolopes) symbiosis. To colonize, V. fischeri first forms a biofilm on the surface of the symbiotic organ, then disperses from it to enter and ultimately colonize sites deep within this organ. Our work has shown that genes required for biofilm formation in laboratory culture are similarly required for host-associated (HA) biofilms and colonization, while genetic changes that enhance biofilm formation in the lab also strikingly enhance HA biofilms and colonization. This strong correlation affords us an exceptional opportunity to develop and test hypotheses about the mechanisms of HA-biofilms, dispersal and subsequent colonization. Our work has revealed that HA biofilms and colonization depend on syp, an 18- gene locus involved in production of SYP polysaccharide, and on multiple sensor kinases and response regulators that control syp transcription and post-transcriptional events. We have recently identified calcium (Ca2+) and nitric oxide (NO) as a strong inducer and inhibitor, respectively, of biofilm formation. Ca2+ is a physiologically relevant signal that appears to affect numerous processes, but how it does so is as-yet unknown. NO, which is produced by the squid and known to influence HA-biofilms, likely impacts one of the sensor kinases required for syp transcription, and we propose to evaluate the underlying mechanisms. We are also poised to identify other physiological signals that promote/inhibit HA biofilms. We have recently uncovered conditions in which dispersal can be visualized in laboratory culture, and have observed that V. fischeri undergoes multiple rounds of formation and dispersal in fully-grown cultures, a result that suggests control by post-transcriptional mechanisms. We have begun to investigate that process by identifying a set of genes involved in controlling dispersal. We propose to develop a mechanistic understanding of these dispersal genes and the factors that control dispersal events as well as to search for others that we predict to exist. We anticipate that this work will provide insights into the mechanisms by which bacteria respond to their environment and transition in and out of multi-cellular communities within an animal host.

抽象的 细菌可以形成多细胞群落，其中单个细胞免受环境侵害 例如抗生素，因为 [1] 被包裹在由多糖和其他物质组成的保护基质中 大分子[2]在生理上不同于自由生活的浮游细胞。生物膜形成增强 细菌定殖表面的能力，包括宿主组织和非生物表面，例如医疗植入物， 并通过传播过程在远端位置播下后续感染的种子。由于这些 根据特征，生物膜中的细菌是大多数医院获得性感染的原因，因此 了解生物膜如何形成以及如何从生物膜中消散至关重要。尽管动物模型众多 已经开发出生物膜形成的方法，但很少（如果有的话）允许目视检查生物膜形成和 扩散事件以及随后的殖民结果的定量分析。一个这样的稳健模型， 然而，可以发现费氏弧菌与鱿鱼（Euprymna scolopes）共生。为了殖民，V. fischeri 首先 在共生器官的表面形成生物膜，然后从共生器官分散进入并最终定殖位点 在这个器官的深处。我们的工作表明，实验室培养中生物膜形成所需的基因是 宿主相关（HA）生物膜和定植也同样需要，而增强的基因变化 实验室中生物膜的形成也显着增强 HA 生物膜和定植。这种强相关性使得 我们有一个绝佳的机会来开发和测试有关 HA 生物膜、扩散机制的假设 以及随后的殖民化。我们的工作表明，HA 生物膜和定植依赖于 syp，一种 18- 参与 SYP 多糖生产以及多种传感器激酶和反应调节器的基因位点 控制 syp 转录和转录后事件。我们最近发现了钙 (Ca2+) 和 一氧化氮（NO）分别作为生物膜形成的强诱导剂和抑制剂。 Ca2+在生理学上是 相关信号似乎会影响许多过程，但它是如何影响的尚不清楚。不，这是 由鱿鱼产生并已知会影响 HA 生物膜，可能会影响一种传感器激酶 syp 转录，我们建议评估潜在机制。我们还准备确定其他 促进/抑制HA生物膜的生理信号。我们最近发现了一些情况 扩散可以在实验室培养中可视化，并且观察到 V. fischeri 经历了多轮 完全生长的培养物中形成和分散的过程，这一结果表明转录后控制 机制。我们已经开始通过识别一组参与控制的基因来研究这个过程。 分散。我们建议对这些分散基因及其影响因素有一个机制上的理解。 控制扩散事件以及寻找我们预测存在的其他事件。我们预计这项工作将 深入了解细菌对其环境的反应以及进出环境的转变机制 动物宿主内的多细胞群落。