Impact of Azithromycin on the Quorum Sensing-Controlled Proteome of Pseudomonas aeruginosa
Impact of Azithromycin on the Quorum Sensing-Controlled Proteome of Pseudomonas aeruginosa
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DOI：
10.1371/journal.pone.0147698
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发表时间：
2016-01-25
期刊：
影响因子：
3.7
通讯作者：
Welch, M.
中科院分区：
文献类型：
--
作者：
Swatton, J. E.;Davenport, P. W.;Welch, M.
据报道，大环内酯类抗生素阿奇霉素（AZM）可改善囊性纤维化患者的临床结局，其中许多患者长期感染铜绿假单胞菌。然而，这种药物的最高临床可达到浓度远低于铜绿假单胞菌的最低抑制浓度，这就提出了为什么AZM表现出治疗活性的问题。早期研究提出的一种可能性是AZM抑制铜绿假单胞菌的群体感应（QS）。为了明确地检验这一假设，需要将AZM处理带来的变化与在相同生长培养基中生长的特定QS突变体相关的变化进行比较，但这还没有完成。在这项工作中，我们使用定量2D-差异凝胶电泳和H-1-NMR光谱足迹分析，以检查是否一系列的临床相关AZM浓度引起蛋白质组和代谢组学的变化，在野生型文化中所看到的那些定义的QS突变体的文化。与早期的报道一致，发现2D凝胶上超过一半的AZM诱导的斑点变化影响QS调节的蛋白质。然而，AZM调节的蛋白质点总体上非常少（与QS相比），并且这些调节的蛋白质总体上仅占全局QS调节子的一小部分（12-13%）。我们的结论是，AZM扰乱QS系统的子调节子，但不阻止QS本身。加强这一概念，我们进一步表明，AZM是能够减弱毒力因子的生产在另一个革兰氏阴性菌分泌大量的外切酶（粘质沙雷氏菌），即使在没有一个功能性QS系统。
The macrolide antibiotic, azithromycin (AZM), has been reported to improve the clinical outcome of cystic fibrosis patients, many of whom are chronically-infected with Pseudomonas aeruginosa. However, the highest clinically-achievable concentrations of this drug are well-below the minimum inhibitory concentration for P. aeruginosa, raising the question of why AZM exhibits therapeutic activity. One possibility that has been raised by earlier studies is that AZM inhibits quorum sensing (QS) by P. aeruginosa. To explicitly test this hypothesis the changes brought about by AZM treatment need to be compared with those associated with specific QS mutants grown alongside in the same growth medium, but this has not been done. In this work, we used quantitative 2D-difference gel electrophoresis and H-1-NMR spectroscopy footprint analysis to examine whether a range of clinically-relevant AZM concentrations elicited proteomic and metabolomic changes in wild-type cultures that were similar to those seen in cultures of defined QS mutants. Consistent with earlier reports, over half of the AZM-induced spot changes on the 2D gels were found to affect QS-regulated proteins. However, AZM modulated very few protein spots overall (compared with QS) and collectively, these modulated proteins comprised only a small fraction (12-13%) of the global QS regulon. We conclude that AZM perturbs a sub-regulon of the QS system but does not block QS per se. Reinforcing this notion, we further show that AZM is capable of attenuating virulence factor production in another Gram-negative species that secretes copious quantities of exoenzymes (Serratia marcescens), even in the absence of a functional QS system.