Brown D M, Hutchison L, Donaldson K, MacKenzie S J, Dick C A J, Stone V
School of Life Sciences, Napier University, 10 Colinton Road, Edinburgh EH10 5DT, UK.
Toxicol Lett. 2007 Jan 10;168(1):1-6. doi: 10.1016/j.toxlet.2006.10.016. Epub 2006 Nov 6.
Reactive oxygen species (ROS) have been implicated in various pulmonary diseases by causing direct injury to lung epithelial cells. Signalling activity of cells through transcription factors such as nuclear factor kappa B (NF-kappaB) and AP-1 have been shown to be regulated by ROS, and the release of pro-inflammatory cytokines demonstrated in the study of inflammatory disease. In this study, we examined the effect of the oxidant tert-butylhydroperoxide (tBHP) on mouse J774 macrophages and its ability to cause the release of the pro-inflammatory cytokine tumour necrosis factor alpha (TNF-alpha). The role of calcium as a signalling molecule was studied using various calcium antagonists. The role of the signalling molecule cAMP was also investigated using phosphodiesterase inhibitors PDE1 and PDE4 families. Oxidative stress was investigated in lung epithelial (A549) cells with and without calcium antagonists and PDE inhibitors with regard to their ability to modulate release of the neutrophil chemoattractant interleukin 8 (IL-8). The oxidant tBHP significantly increased the cytosolic calcium concentration in J774 macrophages, which was prevented by the PDE1 inhibitor. The production of TNF-alpha protein by J774 macrophages was mediated by a pathway involving calcium as addition of calcium antagonists inhibited the tBHP stimulated increase in the cytokine. Inhibitors of both PDE1 and PDE4 completely prevented the tBHP stimulated TNF-alpha release suggesting that the cAMP pathway may be important in the oxidant induced signalling pathway leading to gene expression of pro-inflammatory cytokines. In the presence of oxidant alone, A549 epithelial cells released significant amounts of IL-8, which was inhibited by both calcium antagonist treatment and PDE inhibition treatment. These data suggest that ROS-mediated lung inflammation could be mediated at least in part by calcium and elevated PDE activity associated with decreased cAMP in both macrophages and epithelial cells. Inhibition of these pathways may provide a route for treatment of inflammatory lung diseases.
活性氧（ROS）通过对肺上皮细胞造成直接损伤，与多种肺部疾病有关。细胞通过转录因子如核因子κB（NF-κB）和激活蛋白-1（AP-1）的信号传导活性已被证明受ROS调节，并且在炎症性疾病研究中证实了促炎细胞因子的释放。在本研究中，我们研究了氧化剂叔丁基过氧化氢（tBHP）对小鼠J774巨噬细胞的影响及其引起促炎细胞因子肿瘤坏死因子α（TNF-α）释放的能力。使用各种钙拮抗剂研究了钙作为信号分子的作用。还使用磷酸二酯酶抑制剂PDE1和PDE4家族研究了信号分子cAMP的作用。在有或没有钙拮抗剂和PDE抑制剂的情况下，研究了肺上皮（A549）细胞中氧化应激调节中性粒细胞趋化因子白细胞介素8（IL-8）释放的能力。氧化剂tBHP显著增加了J774巨噬细胞中的胞质钙浓度，这被PDE1抑制剂所阻止。J774巨噬细胞产生TNF-α蛋白是通过一条涉及钙的途径介导的，因为添加钙拮抗剂抑制了tBHP刺激的细胞因子增加。PDE1和PDE4的抑制剂都完全阻止了tBHP刺激的TNF-α释放，这表明cAMP途径可能在导致促炎细胞因子基因表达的氧化剂诱导信号通路中起重要作用。仅在氧化剂存在的情况下，A549上皮细胞释放大量IL-8，这被钙拮抗剂处理和PDE抑制处理所抑制。这些数据表明，ROS介导的肺部炎症可能至少部分由钙和巨噬细胞及上皮细胞中与cAMP降低相关的PDE活性升高所介导。抑制这些途径可能为治疗炎症性肺病提供一条途径。
