N-acylhomoserine lactones antagonize virulence gene expression and quorum sensing in Staphylococcus aureus
N-acylhomoserine lactones antagonize virulence gene expression and quorum sensing in Staphylococcus aureus
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DOI：
10.1128/iai.74.2.910-919.2006
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发表时间：
2006-02-01
影响因子：
3.1
通讯作者：
Williams, P
中科院分区：
文献类型：
--
作者：
Qazi, S;Middleton, B;Williams, P
许多革兰氏阴性菌利用N-酰基博莫丝氨酸内酯（阿勒）介导的群体感应来控制毒力。为了确定革兰氏阳性细菌如金黄色葡萄球菌是否对AHLs有反应，我们使用了生长依赖性lux报告基因融合。暴露S。金黄色葡萄球菌对不同AHLs的光输出和生长的影响表明，3-氧代取代的C10至C14酰基链AHLs以浓度依赖的方式抑制光输出和生长，而短链AHLs没有影响。N-（3-氧代十二烷酰基）-L-高丝氨酸内酯（3-oXo-C-12-HSL）抑制外毒素和细胞壁纤连蛋白结合蛋白的产生，但增强蛋白A的表达。由于这些过程是通过S.金黄色葡萄球菌agr群体感应系统，而这反过来又通过sar调节，我们研究了AHLs对sarA和agr的影响。在亚生长抑制浓度的3-oxo-C-12-HSL下，sarA表达和agr表达均被抑制，表明3-oxo-C-12-HSL的作用至少部分是通过拮抗S.金黄色。铜绿假单胞菌产生3-氧代-C-12-HSL和N-丁酰基-高丝氨酸内酯（C-4-HSL）的用过的培养物上清液也抑制agr表达，尽管C-4-HSL本身在该测定中是无活性的。自S.金黄色葡萄球菌的感染依赖于膜相关蛋白如AgrB、AgrC和AgrD的活性，我们研究了AHL是否干扰了金黄色葡萄球菌。通过测定它们对膜偶极电位的影响来测定金黄色葡萄球菌膜的功能性。从所获得的结合曲线中，3-氧代-C-12-HSL的解离常数为7 μ M，表明存在特异性饱和受体，而C-4-HSL未观察到结合。这些数据表明，长链3-氧代取代的AHLs，如3-氧代-C-12-HSL，能够与S.金黄色葡萄球菌细胞质膜在饱和，具体的方式和在亚生长抑制浓度，下调外毒素的生产和sarA和agr的表达。
Many gram-negative bacteria employ N-acylbomoserine lactone (AHL)-mediated quorum sensing to control virulence. To determine whether gram-positive bacteria such as Staphylococcus aureus respond to AHLs, we used a growth-dependent lux reporter fusion. Exposure of S. aureus to different AHLs revealed that 3-oxo-substituted AHLs with C-10 to C-14 acyl chains inhibited light output and growth in a concentration-dependent manner, while short-chain AHLs had no efect. N-(3-Oxododecanoyl)-L-homoserine lactone (3-oXo-C-12-HSL) inhibited the production of exotoxins and cell wall fibronectin-binding proteins but enhanced protein A expression. Since these processes are reciprocally regulated via the S. aureus agr quorum-sensing system, which in turn, is regulated via sar, we examined the effect of AHLs on sarA and agr. At sub-growth-inhibitory concentrations of 3-oxo-C-12-HSL, both sarA expression and agr expression were inhibited, indicating that the action of 3-oXo-C-12-HSL is mediated at least in part through antagonism of quorum sensing in S. aureus. Spent culture supernatants from Pseudomonas aeruginosa, which produces both 3-oxo-C-12-HSL and N-butanoyl-homoserine lactone (C-4-HSL), also inhibited agr expression, although C-4-HSL itself was inactive in this assay. Since quorum sensing in S. aureus depends on the activities of membrane-associated proteins, such as AgrB, AgrC, and AgrD, we investigated whether AHLs perturbed S. aureus membrane functionality by determining their influence on the membrane dipole potential. From the binding curves obtained, a dissociation constant of 7 mu M was obtained for 3-oxo-C-12-HSL, indicating the presence of a specific saturable receptor, whereas no binding was observed for C-4-HSL. These data demonstrate that long-chain 3-oxo-substituted AHLs, such as 3-oxo-C-12-HSL, are capable of interacting with the S. aureus cytoplasmic membrane in a saturable, specific manner and at sub-growth-inhibitory concentrations, down-regulating exotoxin production and both sarA and agr expression.