Yamauchi Yasuhiro, Okazaki Hitoshi, Desaki Masashi, Kohyama Tadashi, Kawasaki Shin, Yamamoto Kazuhiko, Takizawa Hajime
Department of Respiratory Medicine, University of Tokyo, Graduate School of Medicine, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan.
Clin Sci (Lond). 2004 Jun;106(6):619-25. doi: 10.1042/CS20030262.
Methotrexate (MTX) has been widely used for the treatment of a variety of tumours as well as for inflammatory diseases. MTX-induced pneumonitis has been a serious unpredictable side effect of the treatment and an important clinical problem. However, its mechanism remains largely unclear. Possible causes include allergic, cytotoxic or immunologic reactions to this agent. To elucidate the proinflammatory mechanism of MTX-induced pneumonitis, we evaluated the effect of MTX on the production of IL (interleukin)-8 by human bronchial and alveolar epithelial cells in vitro and the role of p38 MAPK (mitogen-activated protein kinase) in order to clarify the intracellular signal regulating IL-8 expression. MTX induced IL-8 secretion by human bronchial and alveolar epithelial cells in a dose- and time-dependent manner within the range of the clinically observed serum concentrations. Although addition of LPS (lipopolysaccharide) and glucose showed no significant enhancing effect, addition of IL-1beta or TNF-alpha (tumour necrosis factor-alpha) with MTX to bronchial epithelial cells showed a significant augmenting effect. SB203580, the specific inhibitor of p38 MAPK, inhibited MTX-induced IL-8 production. MTX induced the phosphorylation of Thr(180) and Tyr(182) on p38 MAPK. These results suggest that MTX activates bronchial and alveolar epithelial cells to induce IL-8 production through p38 MAPK, which might play an important role as one of the mechanisms of MTX-induced lung inflammation.
甲氨蝶呤（MTX）已被广泛用于治疗多种肿瘤以及炎症性疾病。MTX诱导的肺炎一直是该治疗中严重且不可预测的副作用以及一个重要的临床问题。然而，其机制在很大程度上仍不清楚。可能的原因包括对该药物的过敏、细胞毒性或免疫反应。为了阐明MTX诱导肺炎的促炎机制，我们在体外评估了MTX对人支气管和肺泡上皮细胞白细胞介素（IL）-8产生的影响以及p38丝裂原活化蛋白激酶（MAPK）的作用，以阐明调节IL-8表达的细胞内信号。在临床观察到的血清浓度范围内，MTX以剂量和时间依赖性方式诱导人支气管和肺泡上皮细胞分泌IL-8。尽管添加脂多糖（LPS）和葡萄糖未显示出明显的增强作用，但将IL-1β或肿瘤坏死因子-α（TNF-α）与MTX一起添加到支气管上皮细胞中显示出显著的增强作用。p38 MAPK的特异性抑制剂SB203580抑制了MTX诱导的IL-8产生。MTX诱导p38 MAPK上苏氨酸（Thr）180和酪氨酸（Tyr）182的磷酸化。这些结果表明，MTX通过p38 MAPK激活支气管和肺泡上皮细胞以诱导IL-8产生，这可能作为MTX诱导肺部炎症的机制之一发挥重要作用。
