Protein kinase C-epsilon mediates bradykinin-induced cyclooxygenase-2 expression in human airway smooth muscle cells.
We previously reported that proinflammatory mediator bradykinin (BK) induces cyclooxygenase (COX)-2 expression in human airway smooth muscle (HASM), but the mechanism is unknown in any biological system. Here, we studied the role of specific protein kinase C (PKC) isozyme(s) in COX-2 expression. Among the eight PKC isozymes present in HASM cells, the Ca2+-independent PKC-delta and -epsilon and the Ca2+-dependent PKC-alpha and -betaI were translocated to the nucleus upon BK stimulation. BK-induced COX-2 expression and prostaglandin E2 (PGE2) accumulation were mimicked by the direct PKC activator phorbol 12-myristate 13-acetate (PMA) and inhibited by the broad spectrum PKC inhibitor bisindolylmaleimide I. However, the selective Ca2+-dependent PKC isozyme inhibitor Go 6976 had no effect. Furthermore, the membrane-permeable calcium chelator BAPTA-AM had no effect on BK-induced COX-2 expression and COX activity despite its inhibition of PGE2 accumulation, suggesting the involvement of Ca2+-independent PKC isozymes. Rottlerin, a PKC-delta inhibitor, also had no effect, likely implicating PKC-epsilon. BK-stimulated transcriptional activation of a COX-2 promoter reporter construct was enhanced by overexpression of wild-type PKC-epsilon and abolished by a dominant negative PKC-epsilon, but it was not affected by wild-type or dominant negative PKC-alpha or -delta. Collectively, our results demonstrate that PKC-e mediates BK-induced COX-2 expression in HASM cells.
Division of Respiratory Medicine, City Hospital, University of Nottingham, Nottingham NG5 1PB, UK. linhua.pang@nottingham.ac.uk
Linhua
L
Pang
Mei
M
Nie
Lisa
L
Corbett
Richard
R
Donnelly
Samuel
S
Gray
Alan J
AJ
Knox
D001920:Bradykinin / Q000494:pharmacology*; D002478:Cells, Cultured; D051546:Cyclooxygenase 2; D015232:Dinoprostone / Q000096:biosynthesis; D006801:Humans; D007527:Isoenzymes / Q000096:biosynthesis* / Q000235:genetics / Q000502:physiology*; D008168:Lung / Q000166:cytology / Q000201:enzymology*; D008565:Membrane Proteins; D008954:Models, Biological; D009130:Muscle, Smooth / Q000187:drug effects / Q000201:enzymology* / Q000378:metabolism; D009154:Mutation; D011451:Prostaglandin-Endoperoxide Synthases / Q000096:biosynthesis* / Q000235:genetics; D011493:Protein Kinase C / Q000235:genetics / Q000502:physiology*; D051744:Protein Kinase C-epsilon; D012333:RNA, Messenger / Q000096:biosynthesis; D015533:Transcriptional Activation
D007527:Isoenzymes; D008565:Membrane Proteins; D012333:RNA, Messenger; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; C497255:PRKCE protein, human; D011493:Protein Kinase C; D051744:Protein Kinase C-epsilon; D015232:Dinoprostone; D001920:Bradykinin