Interleukin-1beta enhances bradykinin-induced phosphoinositide hydrolysis and Ca2+ mobilization in canine tracheal smooth-muscle cells: involvement of the Ras/Raf/mitogen-activated protein kinase (MAPK) kinase (MEK)/MAPK pathway.
Elevated levels of several cytokines including interleukin-1beta (IL-1beta) have been detected in airway fluid of asthmatic patients. Inhalation of IL-1beta induced a bronchial hyper-reactivity to contractile agonists. However, the implication of IL-1beta in the pathogenesis of bronchial hyper-reactivity is not completely understood. Therefore, we investigated the effect of IL-1beta on bradykinin (BK)-induced inositol phosphate [Ins(X)P] accumulation and Ca2+ mobilization, and up-regulation of BK receptor density in canine cultured tracheal smooth-muscle cells (TSMCs). Treatment of TSMCs with IL-1beta potentiated BK-induced Ins(X)P accumulation and Ca2+ mobilization. However, there was no effect on the Ins(X)P response induced by endothelin-1, 5-hydroxytryptamine or carbachol. Treatment with platelet-derived growth factor B-chain homodimer (PDGF-BB) also enhanced the BK-induced Ins(X)P response. These enhancements by IL-1beta and PDGF-BB might be due to an up-regulation of BK B(2) receptor density (B(max)), since [(3)H]BK binding to TSMCs was inhibited by the B(2)-selective agonist and antagonist, BK and Hoe 140, but not by B(1)-selective reagents. The enhancing effects of IL-1beta and PDGF-BB on Ins(X)P accumulation, Ca2+ mobilization and B(max) were attenuated by PD98059 [an inhibitor of activation of mitogen-activated protein kinase (MAPK) kinase, MEK] and cycloheximide (an inhibitor of protein synthesis), suggesting that IL-1beta may share a common signalling pathway with PDGF-BB via protein synthesis. Furthermore, overexpression of dominant negative mutants, H-Ras-15A and Raf-N4, significantly suppressed the up-regulation of BK receptors induced by IL-1beta, indicating that Ras and Raf may be required for activation of these kinases. These results suggest that the augmentation of BK-induced responses produced by IL-1beta might be, at least in part, mediated through activation of the Ras/Raf/MEK/MAPK pathway in TSMCs.
Yang
C M
CM
Department of Physiology and Pharmacology, College of Medicine, Chang Gung University, 259 Wen-Hwa 1 Road, Kwei-San, Tao-Yuan, Taiwan. chuenmao@mail.cgu.edu.tw
Chien
C S
CS
Wang
C C
CC
Hsu
Y M
YM
Chiu
C T
CT
Lin
C C
CC
Luo
S F
SF
Hsiao
L D
LD
D000818:Animals; D001920:Bradykinin / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism*; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D004285:Dogs; D005260:Female; D006868:Hydrolysis; D007375:Interleukin-1 / Q000494:pharmacology*; D008297:Male; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009130:Muscle, Smooth / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D010716:Phosphatidylinositols / Q000378:metabolism*; D019908:Proto-Oncogene Proteins c-raf / Q000378:metabolism; D018002:Receptors, Bradykinin / Q000378:metabolism; D014132:Trachea / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D015854:Up-Regulation; D018631:ras Proteins / Q000378:metabolism
D007375:Interleukin-1; D010716:Phosphatidylinositols; D018002:Receptors, Bradykinin; D019908:Proto-Oncogene Proteins c-raf; D020928:Mitogen-Activated Protein Kinases; D018631:ras Proteins; D001920:Bradykinin; D002118:Calcium