Potentiation of Antibiotics against Gram-Negative Bacteria by Polymyxin B Analogue SPR741 from Unique Perturbation of the Outer Membrane
Potentiation of Antibiotics against Gram-Negative Bacteria by Polymyxin B Analogue SPR741 from Unique Perturbation of the Outer Membrane
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DOI：
10.1021/acsinfecdis.9b00159
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发表时间：
2020-06-12
影响因子：
5.3
通讯作者：
Brown, Eric D.
中科院分区：
文献类型：
--
作者：
French, Shawn;Farha, Maya;Brown, Eric D.
革兰氏阴性菌靶向治疗具有克服强大的外膜（OM）屏障的挑战。在这里，我们描述了SPR 741的作用，SPR 741是一种新的多粘菌素B（PMB）类似物，可增强革兰氏阴性病原体中的几种大支架抗生素。使用原子力显微镜探测大肠杆菌的表面拓扑结构，发现在导致抗生素增强的SPR 741浓度下存在大量OM紊乱。相反，在这些相同浓度下观察到非常少的细胞质膜去极化，表明SPR 741主要作用于OM。截断脂多糖（LPS）的核心与遗传扰动独特致敏E。大肠杆菌对SPR 741，这表明LPS核心残基保持SPR 741在OM，在那里它可以加强一个联合药物，而不是允许它进入细胞质膜。此外，启动子活性测定显示，SPR741激发诱导RcsAB的表达，RcsAB是OM扰动的应激传感器。总之，这些结果表明SPR 741主要与OM相互作用，与PMB和粘菌素在外膜和细胞质膜两者处的双重作用相反。
Therapeutics targeting Gram-negative bacteria have the challenge of overcoming a formidable outer membrane (OM) barrier. Here, we characterize the action of SPR741, a novel polymyxin B (PMB) analogue shown to potentiate several large-scaffold antibiotics in Gram-negative pathogens. Probing the surface topology of Escherichia coli using atomic force microscopy revealed substantial OM disorder at concentrations of SPR741 that lead to antibiotic potentiation. Conversely, very little cytoplasmic membrane depolarization was observed at these same concentrations, indicating that SPR741 acts predominately on the OM. Truncating the lipopolysaccharide (LPS) core with genetic perturbations uniquely sensitized E. coli to SPR741, suggesting that LPS core residues keep SPR741 at the OM, where it can potentiate a codrug, rather than permit its entry to the cytoplasmic membrane. Further, a promoter activity assay revealed that SPR741 challenge induced the expression of RcsAB, a stress sensor for OM perturbation. Together, these results indicate that SPR741 interacts predominately with the OM, in contrast to the dual action of PMB and colistin at both the outer and cytoplasmic membranes.