Reactive Oxygen Species Contribute to the Bactericidal Effects of the Fluoroquinolone Moxifloxacin in Streptococcus pneumoniae
Reactive Oxygen Species Contribute to the Bactericidal Effects of the Fluoroquinolone Moxifloxacin in Streptococcus pneumoniae
复制标题
DOI：
10.1128/aac.02299-15
复制
发表时间：
2016-01-01
影响因子：
4.9
通讯作者：
de la Campa, A. G.
中科院分区：
文献类型：
--
作者：
Ferrandiz, M. J.;Martin-Galiano, A. J.;de la Campa, A. G.
我们研究了肺炎链球菌对氟喹诺酮类药物莫西沙星在抑制DNA旋转酶时的转录反应。野生型菌株R6在10倍最低抑菌浓度下处理30分钟后，触发了涉及132个基因的反应。参与丙酮酸产生的几种代谢途径的基因表达上调。这些酶包括3种糖酵解酶，最终将6-磷酸果糖转化为丙酮酸，以及2种将磷酸糖输送到糖酵解途径中的酶。此外，乙酰辅酶A(乙酰辅酶A)羧基酶表达下调，可能导致乙酰辅酶A增加。当配合甲酸乙酰转移酶的上调时，乙酰-辅酶A的增加将增加丙酮酸的产量。由于丙酮酸被丙酮酸氧化酶(SpxB)转化为过氧化氢(H_2O_2)，丙酮酸的增加会增加细胞内的H_2O_2。在这里，我们证实了在用莫西沙星处理4小时内，培养物中过氧化氢的产生增加了21倍，羟基自由基量增加了55倍。这种通过芬顿反应增加的羟基自由基会破坏DNA、脂质和蛋白质。这些活性氧物种导致了药物的致命性，这一结论得到了观察到的SpxB缺失的保护作用的支持。这些结果支持氟喹诺酮类药物引起氧化还原改变的模型。肺炎链球菌对莫西沙星的转录反应与对拓扑异构酶IV的抑制剂左氧氟沙星的反应进行了比较。左氧氟沙星触发了铁运输基因的转录激活，也增强了Fenton反应。
We studied the transcriptomic response of Streptococcus pneumoniae to the fluoroquinolone moxifloxacin at a concentration that inhibits DNA gyrase. Treatment of the wild-type strain R6, at a concentration of 10x the MIC, triggered a response involving 132 genes after 30 min of treatment. Genes from several metabolic pathways involved in the production of pyruvate were upregulated. These included 3 glycolytic enzymes, which ultimately convert fructose 6-phosphate to pyruvate, and 2 enzymes that funnel phosphate sugars into the glycolytic pathway. In addition, acetyl coenzyme A (acetyl-CoA) carboxylase was downregulated, likely leading to an increase in acetyl-CoA. When coupled with an upregulation in formate acetyltransferase, an increase in acetyl-CoA would raise the production of pyruvate. Since pyruvate is converted by pyruvate oxidase (SpxB) into hydrogen peroxide (H2O2), an increase in pyruvate would augment intracellular H2O2. Here, we confirm a 21-fold increase in the production of H2O2 and a 55-fold increase in the amount of hydroxyl radical in cultures treated during 4 h with moxifloxacin. This increase in hydroxyl radical through the Fenton reaction would damage DNA, lipids, and proteins. These reactive oxygen species contributed to the lethality of the drug, a conclusion supported by the observed protective effects of an SpxB deletion. These results support the model whereby fluoroquinolones cause redox alterations. The transcriptional response of S. pneumoniae to moxifloxacin is compared with the response to levofloxacin, an inhibitor of topoisomerase IV. Levofloxacin triggers the transcriptional activation of iron transport genes and also enhances the Fenton reaction.