Membrane Distribution of the Pseudomonas Quinolone Signal Modulates Outer Membrane Vesicle Production in Pseudomonas aeruginosa.
Membrane Distribution of the Pseudomonas Quinolone Signal Modulates Outer Membrane Vesicle Production in Pseudomonas aeruginosa.
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DOI：
10.1128/mbio.01034-17
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发表时间：
2017-08-08
期刊：
影响因子：
6.4
通讯作者：
Schertzer JW
中科院分区：
文献类型：
--
作者：
Florez C;Raab JE;Cooke AC;Schertzer JW
假单胞菌喹诺酮信号（PQS）是铜绿假单胞菌中重要的群体感应分子，通过刺激外膜囊泡（OMV）的形成来介导自身的包装和转运。由于OMV与许多与服从相关的行为有关，因此我们了解它们是如何形成的至关重要。我们小组提出了OMV生物发生的双层耦合模型，其中PQS插入外膜，引起外叶扩张，从而诱导弯曲。根据该模型，我们假设PQS必须从细胞质转运到外膜才能启动OMV的形成。我们最初检查了两种实验室铜绿假单胞菌菌株，发现了显著的菌株依赖性差异。PQS出口与OMV生产密切相关，即使等量的总PQS生产的两种菌株。有趣的是，我们发现，贫穷的OMV生产者隔离的大部分PQS在内膜，这似乎是早期饱和的输出途径的结果。进一步的分析表明，菌株特异性PQS输出和OMV生物发生模式一旦建立是稳定的，但可以通过改变生长培养基显着改变。最后，我们证明了实验室菌株所描述的相关性也适用于三种临床菌株。这些结果表明，控制PQS输出的因素决定了OMV的生物成因。这项工作为PQS控制铜绿假单胞菌的毒力提供了新的见解，并为进一步研究信号输出和OMV生物发生提供了重要工具。细菌分泌物已被认为是微生物致病和人类疾病的重要方面。已经发现许多毒力因子在外膜囊泡（OMV）内转运，并且使用这些生物纳米颗粒的递送通常导致增加的效力。OMV生物发生是一个重要但知之甚少的过程，在革兰氏阴性菌中普遍存在。我们的研究小组试图了解OMV形成背后的生化机制，并开发了一种小分子诱导的膜弯曲模型，作为这一过程的重要驱动力。通过这项工作，我们证明了PQS，一种已知的小分子OMV诱导剂，必须输出以促进实验室适应和临床铜绿假单胞菌菌株中的OMV生物合成。在支持和扩大双层夫妇模型的OMV生物发生，目前的工作奠定了基础，研究环境和遗传因素，调节OMV生产，因此，包装和交付的许多细菌因子。
The Pseudomonas quinolone signal (PQS) is an important quorum-sensing molecule in Pseudomonas aeruginosa that also mediates its own packaging and transport by stimulating outer membrane vesicle (OMV) formation. Because OMVs have been implicated in many virulence-associated behaviors, it is critical that we understand how they are formed. Our group proposed the bilayer-couple model for OMV biogenesis, where PQS intercalates into the outer membrane, causing expansion of the outer leaflet and consequently inducing curvature. In accordance with the model, we hypothesized that PQS must be transported from the cytoplasm to the outer membrane before it can initiate OMV formation. We initially examined two laboratory strains of P. aeruginosa and found significant strain-dependent differences. PQS export correlated strongly with OMV production, even though equivalent amounts of total PQS were produced by both strains. Interestingly, we discovered that poor OMV producers sequestered the majority of PQS in the inner membrane, which appeared to be the result of early saturation of the export pathway. Further analysis showed that strain-specific PQS export and OMV biogenesis patterns were stable once established but could be significantly altered by changing the growth medium. Finally, we demonstrated that the associations described for laboratory strains also held for three clinical strains. These results suggest that factors controlling the export of PQS dictate OMV biogenesis. This work provides new insight into PQS-controlled virulence in P. aeruginosa and provides important tools to further study signal export and OMV biogenesis. Bacterial secretion has been recognized as an essential facet of microbial pathogenesis and human disease. Numerous virulence factors have been found to be transported within outer membrane vesicles (OMVs), and delivery using these biological nanoparticles often results in increased potency. OMV biogenesis is an important but poorly understood process that is ubiquitous among Gram-negative organisms. Our group seeks to understand the biochemical mechanisms behind the formation of OMVs and has developed a model of small-molecule-induced membrane curvature as an important driver of this process. With this work, we demonstrate that PQS, a known small-molecule OMV inducer, must be exported to promote OMV biogenesis in both lab-adapted and clinical strains of Pseudomonas aeruginosa. In supporting and expanding the bilayer-couple model of OMV biogenesis, the current work lays the groundwork for studying environmental and genetic factors that modulate OMV production and, consequently, the packaging and delivery of many bacterial factors.