Comparative Metabolomics and Transcriptomics Reveal Multiple Pathways Associated with Polymyxin Killing in Pseudomonas aeruginosa
Comparative Metabolomics and Transcriptomics Reveal Multiple Pathways Associated with Polymyxin Killing in Pseudomonas aeruginosa
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DOI：
10.1128/msystems.00149-18
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发表时间：
2019-01-01
期刊：
影响因子：
6.4
通讯作者：
Li, Jian
中科院分区：
文献类型：
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作者：
Han, Mei-Ling;Zhu, Yan;Li, Jian
多粘菌素是对抗多药耐药铜绿假单胞菌的最后一线疗法；然而，对多粘菌素的耐药性已越来越多地被报道。因此，了解多粘菌素的活性和耐药机制对于保持其临床应用至关重要。本研究采用比较代谢组学和转录组学方法，研究了敏感多粘菌素的铜绿假单胞菌PAK(MIC，1 mg/L)及其耐多粘菌素突变体PAKpmrB6(MIC，16 mg/L)对多粘菌素B(4，8和128 mg/L)在1、4和24 h的反应。结果表明，4 mg/L的多粘菌素B对敏感和耐药的铜绿假单胞菌诱导了不同的代谢和转录反应。在PAK菌株中，多粘菌素B显著激活PmrAB和介导的ARN操纵子，导致4-氨基-4-脱氧-L-阿拉伯糖(L-Ara4N)的合成增加和脂质A的添加。此外，多粘菌素B显著降低了PAK菌株的脂多糖和肽聚糖的合成，而增加了PAKpmrB6菌株的脂多糖和肽聚糖的合成。此外，4 mg/L多粘菌素B显著扰乱了菌株PAK的磷脂和脂肪酸水平，并诱导了氧化应激，但对PAKpmrB6菌株没有影响。值得注意的是，海藻糖-6-磷酸水平的增加表明多粘菌素B可能导致两个菌株的渗透平衡。此外，8 mg/L和128 mg/L多粘菌素B显著提高了野生型和突变型菌株的脂氨基酸水平，降低了磷脂水平，但对脂类A的修饰没有显著影响。总体而言，这项系统研究是第一次阐明与多粘菌素对铜绿假单胞菌作用模式相关的多个细胞通路的复杂和动态相互作用。由于多药耐药性，铜绿假单胞菌已被最近的世卫组织全球优先病原菌名单所强调。如果没有新的抗生素，多粘菌素仍然是这种难以治疗的病原体的最后治疗选择。多粘菌素耐药性的出现突显了对我们已经非常有限的抗生素设施的日益增长的威胁，以及了解多粘菌素活性和耐药性的确切机制的紧迫性。结合相关的代谢组学和转录组学结果，本研究发现，多粘菌素处理引起了脂类、脂多糖和肽聚糖的生物合成、中枢碳代谢和氧化应激的显著干扰。重要的是，在临床相关浓度的多粘菌素治疗下，脂蛋白A的改变速度惊人地快。这是首次在系统水平上揭示多粘菌素诱导的细胞反应的动力学，这强调了应该考虑联合治疗，以最大限度地减少对最后一线多粘菌素的耐药性。这些结果还提供了急需的机制信息，这可能有助于新一代多粘菌素的发现。
Polymyxins are a last-line therapy against multidrug-resistant Pseudomonas aeruginosa; however, resistance to polymyxins has been increasingly reported. Therefore, understanding the mechanisms of polymyxin activity and resistance is crucial for preserving their clinical usefulness. This study employed comparative metabolomics and transcriptomics to investigate the responses of polymyxin-susceptible P. aeruginosa PAK (polymyxin B MIC, 1 mg/liter) and its polymyxin-resistant pmrB mutant PAKpmrB6 (MIC, 16 mg/liter) to polymyxin B (4, 8, and 128 mg/liter) at 1, 4, and 24 h, respectively. Our results revealed that polymyxin B at 4 mg/liter induced different metabolic and transcriptomic responses between polymyxin-susceptible and -resistant P. aeruginosa. In strain PAK, polymyxin B significantly activated PmrAB and the mediated arn operon, leading to increased 4-amino-4-deoxy-L-arabinose (L-Ara4N) synthesis and the addition to lipid A. In contrast, polymyxin B did not increase lipid A modification in strain PAKpmrB6. Moreover, the syntheses of lipopolysaccharide and peptidoglycan were significantly decreased in strain PAK but increased in strain PAKpmrB6 due to polymyxin B treatment. In addition, 4 mg/liter polymyxin B significantly perturbed phospholipid and fatty acid levels and induced oxidative stress in strain PAK, but not in PAKpmrB6. Notably, the increased trehalose-6-phosphate levels indicate that polymyxin B potentially caused osmotic imbalance in both strains. Furthermore, 8 and 128 mg/liter polymyxin B significantly elevated lipoamino acid levels and decreased phospholipid levels but without dramatic changes in lipid A modification in wild-type and mutant strains, respectively. Overall, this systems study is the first to elucidate the complex and dynamic interactions of multiple cellular pathways associated with the polymyxin mode of action against P. aeruginosa.IMPORTANCE Pseudomonas aeruginosa has been highlighted by the recent WHO Global Priority Pathogen List due to multidrug resistance. Without new antibiotics, polymyxins remain a last-line therapeutic option for this difficult-to-treat pathogen. The emergence of polymyxin resistance highlights the growing threat to our already very limited antibiotic armamentarium and the urgency to understand the exact mechanisms of polymyxin activity and resistance. Integration of the correlative metabolomics and transcriptomics results in the present study discovered that polymyxin treatment caused significant perturbations in the biosynthesis of lipids, lipopolysaccharide, and peptidoglycan, central carbon metabolism, and oxidative stress. Importantly, lipid A modifications were surprisingly rapid in response to polymyxin treatment at clinically relevant concentrations. This is the first study to reveal the dynamics of polymyxin-induced cellular responses at the systems level, which highlights that combination therapy should be considered to minimize resistance to the last-line polymyxins. The results also provide much-needed mechanistic information which potentially benefits the discovery of new-generation polymyxins.