Rifampin- or Capreomycin-Induced Remodeling of the Mycobacterium smegmatis Mycolic Acid Layer Is Mitigated in Synergistic Combinations with Cationic Antimicrobial Peptides
Rifampin- or Capreomycin-Induced Remodeling of the Mycobacterium smegmatis Mycolic Acid Layer Is Mitigated in Synergistic Combinations with Cationic Antimicrobial Peptides
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DOI：
10.1128/msphere.00218-18
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发表时间：
2018-07-01
期刊：
影响因子：
4.8
通讯作者：
Mason, A. James
中科院分区：
文献类型：
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作者：
Man, DeDe Kwun-Wai;Kanno, Tokuwa;Mason, A. James
分枝杆菌细胞壁对抗生素具有天然耐药性。抗菌肽 (AMP) 可改变分枝杆菌的表面特性，并可与不同类别的抗生素产生协同作用。在这里，我们研究了耻垢分枝杆菌对利福平或卷曲霉素单独或与两种合成的阳离子α-螺旋 AMP 组合的反应，这两种 AMP 的区别是存在（D-LAK120-HP13）或不存在（D-LAK120-A）诱导扭结的脯氨酸。通过结合高分辨率魔角旋转核磁共振 (HR-MAS NMR) 代谢组学、二苯基己三烯 (DPH) 荧光各向异性测量和劳丹发射光谱，我们发现耻垢分枝杆菌通过显着改变其代谢，特别是通过重塑细胞包膜来响应利福平或卷曲霉素的攻击。总体而言，这些变化与海藻糖二分枝菌酸酯的减少和海藻糖单分枝菌酸酯的增加一致，并且与卷曲霉素而非利福平攻击后观察到的分枝菌酸层刚性增加相关。用 D-LAK120-A 或 D-LAK120-HP13 进行的攻击分别不会引起菌膜代谢物的变化或引起适度的变化，并且不会引起分枝菌酸层刚性的显着增加。此外，当利福平或卷曲霉素分别与 D-LAK120-HP13 和 D-LAK120-A 组合时，对利福平或卷曲霉素的反应显着降低，这表明这些组合的协同作用的可能机制。因此，耻垢分枝杆菌中菌膜的重塑被认为是对抗利福平或卷曲霉素的重要对策，但通过将药物与 AMP 结合，可以减轻这种情况，并增强利福平或卷曲霉素的功效。 重要性 我们使用了组合的 NMR 代谢组学/生物物理方法来更好地了解两种密切相关的抗菌肽机制的差异，以及模型生物耻垢分枝杆菌的反应用针对分枝杆菌病原体的一线或二线抗生素进行挑战。我们发现，除了膜损伤之外，氧化应激的触发可能是一种 AMP 作用机制的重要组成部分。伴随利福平，特别是卷曲霉素挑战的代谢变化分别与菌膜中的适度和更显着的变化相关，这为对一种抗生素的反应如何影响细菌渗透进而影响另一种抗生素的作用提供了理论依据。这项研究首次揭示了抗菌肽如何与现有抗生素协同作用，这些抗生素的功效正在减弱或使耐多药分枝杆菌和/或潜在分枝杆菌感染对其敏感，从而延长这些药物的使用寿命。
The mycobacterial cell wall affords natural resistance to antibiotics. Antimicrobial peptides (AMPs) modify the surface properties of mycobacteria and can act synergistically with antibiotics from differing classes. Here, we investigate the response of Mycobacterium smegmatis to the presence of rifampin or capreomycin, either alone or in combination with two synthetic, cationic, a-helical AMPs that are distinguished by the presence (D-LAK120-HP13) or absence (D-LAK120-A) of a kink-inducing proline. Using a combination of high-resolution magic angle spinning nuclear magnetic resonance (HR-MAS NMR) metabolomics, diphenylhexatriene (DPH) fluorescence anisotropy measurements, and laurdan emission spectroscopy, we show that M. smegmatis responds to challenge with rifampin or capreomycin by substantially altering its metabolism and, in particular, by remodeling the cell envelope. Overall, the changes are consistent with a reduction of trehalose dimycolate and an increase of trehalose monomycolate and are associated with increased rigidity of the mycolic acid layer observed following challenge by capreomycin but not rifampin. Challenge with D-LAK120-A or D-LAK120-HP13 induced no or modest changes, respectively, in mycomembrane metabolites and did not induce a significant increase in the rigidity of the mycolic acid layer. Furthermore, the response to rifampin or capreomycin was significantly reduced when these were combined with D-LAK120-HP13 and D-LAK120-A, respectively, suggesting a possible mechanism for the synergy of these combinations. The remodeling of the mycomembrane in M. smegmatis is therefore identified as an important countermeasure deployed against rifampin or capreomycin, but this can be mitigated and the efficacy of rifampin or capreomycin potentiated by combining the drug with AMPs.IMPORTANCE We have used a combined NMR metabolomics/biophysical approach to better understand differences in the mechanisms of two closely related antimicrobial peptides, as well as the response of the model organism Mycobacterium smegmatis to challenge with first- or second-line antibiotics used against mycobacterial pathogens. We show that, in addition to membrane damage, the triggering of oxidative stress may be an important part of the mechanism of action of one AMP. The metabolic shift that accompanied rifampin and, particularly, capreomycin challenge was associated with modest and more dramatic changes, respectively, in the mycomembrane, providing a rationale for how the response to one antibiotic may affect bacterial penetration and, hence, the action of another. This study presents the first insights into how antimicrobial peptides may operate synergistically with existing antibiotics whose efficacy is waning or sensitize MDR mycobacteria and/or latent mycobacterial infections to them, prolonging the useful life of these drugs.