Griffith Health Institute, Griffith University, Queensland, Australia; School of Pharmacy, Griffith University, Queensland, Australia.
Griffith Health Institute, Griffith University, Queensland, Australia; School of Medical Science, Griffith University, Queensland, Australia.
Chem Biol Interact. 2014 Feb 5;208:58-63. doi: 10.1016/j.cbi.2013.11.016. Epub 2013 Dec 5.
Pyocyanin (PCN), a virulence factor produced by Pseudomonas aeruginosa, has many damaging effects on mammalian cells. Several lines of evidence suggest that this damage is primarily mediated by its ability to generate oxidative stress. However mechanisms underlying PCN-induced oxidative injury remain unclear. Although oxidative stress and subsequent MAPK signaling has been shown to modulate cell death in other models, its role in PCN-induced cytotoxicity remains unknown. Therefore the aim of this study was to investigate the role of redox-sensitive MAPK in PCN-induced toxicity in A549 cells. Here we show that PCN (50μM) rapidly increased ERK1/2 phosphorylation after 5min. Pre-treatment of A549 cells with the MEK1/2 inhibitor U0126 (10μM) decreased PCN-induced ERK1/2 phosphorylation and protected cells against apoptosis and cell injury suggesting a role for ERK signalling. In contrast, JNK and p38 MAPK phosphorylation remained unchanged following exposure to PCN and pretreatment with either the JNK or p38 MAPK inhibitors (10μM SP600125 and 10μM SB203580, respectively) did not afford protection against PCN toxicity. This would suggest that PCN-induced cytotoxicity appears to occur independently of JNK and p38 MAPK signaling pathways. Finally, although we confirm that oxidative stress contributes to PCN-induced toxicity, our data suggest the contribution of oxidative stress is independent of ERK1/2 signaling. These findings may provide insight for novel targeted therapies to reduce PCN-mediated lung injury in patients with chronic P. aeruginosa respiratory infections.
绿脓菌素 (PCN) 是铜绿假单胞菌产生的一种毒力因子，对哺乳动物细胞有许多损伤作用。有几条证据表明，这种损伤主要是由其产生氧化应激的能力介导的。然而，PCN 诱导的氧化损伤的机制尚不清楚。虽然氧化应激和随后的 MAPK 信号转导已被证明在其他模型中调节细胞死亡，但它在 PCN 诱导的细胞毒性中的作用尚不清楚。因此，本研究旨在探讨氧化还原敏感的 MAPK 在 PCN 诱导的 A549 细胞毒性中的作用。在这里，我们表明 PCN（50μM）在 5 分钟后迅速增加 ERK1/2 的磷酸化。用 MEK1/2 抑制剂 U0126（10μM）预处理 A549 细胞可降低 PCN 诱导的 ERK1/2 磷酸化，并保护细胞免受凋亡和细胞损伤，表明 ERK 信号转导的作用。相反，暴露于 PCN 后 JNK 和 p38 MAPK 的磷酸化保持不变，并且用 JNK 或 p38 MAPK 抑制剂（分别为 10μM SP600125 和 10μM SB203580）预处理不能防止 PCN 毒性。这表明 PCN 诱导的细胞毒性似乎独立于 JNK 和 p38 MAPK 信号通路。最后，尽管我们证实氧化应激有助于 PCN 诱导的毒性，但我们的数据表明氧化应激的贡献独立于 ERK1/2 信号。这些发现可能为减少慢性铜绿假单胞菌呼吸道感染患者中 PCN 介导的肺损伤的新型靶向治疗提供依据。
