Mitogen-activated protein kinase signalling pathways in IL-1 beta-dependent rat airway smooth muscle proliferation.
Asthma is associated with abnormal airway smooth muscle (ASM) growth that may contribute to airway narrowing and hyperresponsiveness. We investigated the role of mitogen-activated protein kinase (MAPK) pathway in IL-1beta induced ASM proliferation in the rat. Rat tracheal ASM cells were dissociated and maintained in culture. We examined the effect of selective MAPK inhibitors, SB239063 (a p38 MAPK inhibitor), U0126 (a mitogen-activated and extracellular regulated kinase kinase, MEK-1, inhibitor which inhibits downstream extracellular regulated kinase, ERK, activity), and SP600125 (a c-jun N-terminal kinase, JNK, inhibitor) on IL-1beta-induced proliferation. Proliferation of ASM cells was significantly increased following exposure to IL-1beta in a dose-dependent manner. p38, JNK and ERK MAPKs were activated by IL-1beta in a time-dependent manner, with peak activation time at 30, 60 min and at 6 h, respectively. This activation was inhibited by their respective inhibitors. SP600125 (20 microM) had no effect on IL-1beta-induced ERK and p38 phosphorylation. SB239063, U0126 and SP600125 dose-dependently inhibited IL-1beta-dependent proliferation at doses that inhibit the activities of p38, ERK and JNK MAPKs, respectively. No additive or synergistic effects were observed on proliferative responses with any combination of these compounds. In conclusion, the three major MAPK pathways, ERK as well as the p38 MAPK and JNK pathways, are independent regulators of IL-1beta-dependent proliferation of rat ASM.
Thoracic Medicine, National Heart and Lung Institute, Imperial College, Dovehouse St, London SW3 6LY, UK.
Wenwu
W
Zhai
Paul R
PR
Eynott
Ute
U
Oltmanns
Sum Yee
SY
Leung
Kian Fan
KF
Chung
D000818:Animals; D049109:Cell Proliferation / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007375:Interleukin-1 / Q000502:physiology*; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology*; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009130:Muscle, Smooth / Q000187:drug effects / Q000201:enzymology* / Q000502:physiology; D051381:Rats; D011914:Rats, Inbred BN; D014132:Trachea / Q000187:drug effects / Q000201:enzymology* / Q000502:physiology
D004791:Enzyme Inhibitors; D007375:Interleukin-1; D020928:Mitogen-Activated Protein Kinases