Theophylline inhibits NF-kappa B activation and I kappa B alpha degradation in human pulmonary epithelial cells.
Previous studies demonstrated that theophylline modulates NF-kappaB activation in mast cells and pulmonary epithelial cells. We examined whether or not this modulation of NF-kappaB activation by theophylline is due to inhibition of the degradation of the IKBalpha protein, which suppresses NF-kappaB activation. TNF-alpha-induced NF-kappaB activation in a human pulmonary epithelial cell line (A549) was evaluated by Western blotting and a chloramphenicol acetyltransferase (CAT) assay. Expression of the IkappaBalpha protein was evaluated by Western blotting. Western blotting of nuclear extracts of A549 cells demonstrated that theophylline suppresses NF-kappaB-p65 nuclear translocation. The CAT assay indicated that NF-kappaB-dependent reporter gene expression is inhibited in A549 cells pretreated with theophylline. Western blotting of cytoplasmic extracts of A549 cells revealed that this inhibition was linked to theophylline-induced protection of expression of the IkappaBalpha protein. Moreover, theophylline inhibited interleukin-6 production induced by TNF-alpha in A549 cells. These findings are consistent with the idea that theophylline suppresses the production of proinflammatory cytokines via inhibition of NF-kappaB activation through protection of the IkappaBalpha protein.
Ichiyama
T
T
Department of Pediatrics, Yamaguchi University School of Medicine, Ube, Japan. ichiyama@po.cc.yamaguchi-u.ac.jp
Hasegawa
S
S
Matsubara
T
T
Hayashi
T
T
Furukawa
S
S
D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology; D001993:Bronchodilator Agents / Q000494:pharmacology; D004268:DNA-Binding Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D006801:Humans; D020672:I-kappa B Proteins; D007249:Inflammation / Q000276:immunology / Q000517:prevention & control; D015850:Interleukin-6 / Q000378:metabolism; D008168:Lung / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000037:antagonists & inhibitors* / Q000378:metabolism; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D020545:Respiratory Mucosa / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D013806:Theophylline / Q000494:pharmacology*; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors / Q000494:pharmacology; D000093242:Interleukin-6 Inhibitors
D000894:Anti-Inflammatory Agents, Non-Steroidal; D001993:Bronchodilator Agents; D004268:DNA-Binding Proteins; D020672:I-kappa B Proteins; D015850:Interleukin-6; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B; D010726:Phosphodiesterase Inhibitors; D013806:Theophylline; D014409:Tumor Necrosis Factor-alpha; D000093242:Interleukin-6 Inhibitors; C000606204:NFKBIA protein, human