Chemical Screen for Vancomycin Antagonism Uncovers Probes of the Gram-Negative Outer Membrane
Chemical Screen for Vancomycin Antagonism Uncovers Probes of the Gram-Negative Outer Membrane
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DOI：
10.1021/acschembio.1c00179
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发表时间：
2021-05-11
影响因子：
4
通讯作者：
Brown, Eric D.
中科院分区：
文献类型：
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作者：
Klobucar, Kristina;Cote, Jean-Philippe;Brown, Eric D.
革兰氏阴性菌的外膜是一个强大的渗透屏障，只允许一小部分化学物质渗透。这种外膜屏障可能会阻碍细胞过程和化合物作用机制的研究，因为许多化合物（包括抗生素）尽管具有细胞内靶点，但仍无法进入。因此，外膜透化化合物是此类研究中的宝贵工具。已知干扰外膜的许多现有化合物也影响内膜完整性，例如多粘菌素及其衍生物，使这些探针具有非特异性。我们进行了类似的140 000不同的合成化合物的筛选，对于那些拮抗万古霉素在15摄氏度的大肠杆菌中的生长抑制活性，以丰富能够扰动外膜的化学物质。这导致了这样的发现，即livestatin-1（一种人类细胞中铁凋亡的抑制剂）和MAC-0568743（一种新型阳离子两亲物）可以增强大支架抗生素的活性，在37 ℃下对革兰氏阴性菌的渗透率较低。发现利司他汀-1和MAC-0568743通过与外膜的外小叶中的脂多糖相互作用物理破坏外膜的完整性。我们表明，这些化合物选择性地破坏外膜，同时最小限度地影响内膜完整性，特别是在增强革兰氏阳性靶向抗生素所需的浓度下。对这些分子及其结构类似物的进一步探索是开发外膜特异性探针的一条有前途的途径。
The outer membrane of Gram-negative bacteria is a formidable permeability barrier which allows only a small subset of chemical matter to penetrate. This outer membrane barrier can hinder the study of cellular processes and compound mechanism of action, as many compounds including antibiotics are precluded from entry despite having intracellular targets. Consequently, outer membrane permeabilizing compounds are invaluable tools in such studies. Many existing compounds known to perturb the outer membrane also impact inner membrane integrity, such as polymyxins and their derivatives, making these probes nonspecific. We performed a screen of similar to 140 000 diverse synthetic compounds, for those that antagonized the growth inhibitory activity of vancomycin at 15 degrees C in Escherichia coli, to enrich for chemicals capable of perturbing the outer membrane. This led to the discovery that liproxstatin-1, an inhibitor of ferroptosis in human cells, and MAC-0568743, a novel cationic amphiphile, could potentiate the activity of large-scaffold antibiotics with low permeation into Gram-negative bacteria at 37 degrees C. Liproxstatin-1 and MAC-0568743 were found to physically disrupt the integrity of the outer membrane through interactions with lipopolysaccharide in the outer leaflet of the outer membrane. We showed that these compounds selectively disrupt the outer membrane while minimally impacting inner membrane integrity, particularly at the concentrations needed to potentiate Gram-positive-targeting antibiotics. Further exploration of these molecules and their structural analogues is a promising avenue for the development of outer membrane specific probes.