title: Methotrexate induces interleukin-8 production by human bronchial and alveolar epithelial cells.
abstract: 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.
authors.affiliation: Department of Respiratory Medicine, University of Tokyo, Graduate School of Medicine, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Yamauchi
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Okazaki
authors.forename: Masashi
authors.initials: M
authors.lastname: Desaki
authors.forename: Tadashi
authors.initials: T
authors.lastname: Kohyama
authors.forename: Shin
authors.initials: S
authors.lastname: Kawasaki
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Yamamoto
authors.forename: Hajime
authors.initials: H
authors.lastname: Takizawa
mesh_terms: D000111:Acetylcysteine / Q000494:pharmacology; D001980:Bronchi / Q000187:drug effects* / Q000378:metabolism; D002460:Cell Line; D003513:Cycloheximide / Q000494:pharmacology; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism; D005493:Folic Acid Antagonists / Q000009:adverse effects / Q000494:pharmacology*; D016166:Free Radical Scavengers / Q000494:pharmacology; D005947:Glucose / Q000494:pharmacology; D006801:Humans; D007003:Hypoglycemia / Q000378:metabolism; D007375:Interleukin-1 / Q000494:pharmacology; D016209:Interleukin-8 / Q000096:biosynthesis*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008727:Methotrexate / Q000009:adverse effects / Q000494:pharmacology*; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D010766:Phosphorylation; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D011650:Pulmonary Alveoli / Q000187:drug effects* / Q000378:metabolism; D013912:Threonine / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D014443:Tyrosine / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases
chemical_list: D005493:Folic Acid Antagonists; D016166:Free Radical Scavengers; D007375:Interleukin-1; D016209:Interleukin-8; D008070:Lipopolysaccharides; D011500:Protein Synthesis Inhibitors; D014409:Tumor Necrosis Factor-alpha; D013912:Threonine; D014443:Tyrosine; D003513:Cycloheximide; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D005947:Glucose; D000111:Acetylcysteine; D008727:Methotrexate