Involvement of protein kinase C-gamma in IL-1beta-induced cyclooxygenase-2 expression in human pulmonary epithelial cells.
The signaling pathway of protein kinase C (PKC) is known to play a role in mediating the action of various cytokines. Here we examined the signal transduction pathway of PKC activation and the role of PKC isoforms in interleukin-1beta (IL-1beta)-mediated cyclooxygenase-2 (COX-2) expression in human pulmonary epithelial cell line (A549). The tyrosine kinase inhibitors (genistein and tyrphostin AG126) and phosphatidylcholine-phospholipase C inhibitor (D-609) prevented IL-1beta-induced prostaglandin E(2) (PGE(2)) release and COX-2 expression, whereas U-73122 (a phosphatidylinositol-phospholipase C inhibitor) and propranolol (a phosphatidate phosphohydrolase inhibitor) had no effect. The PKC inhibitors (Go 6976 and Ro 31-8220) and NF-kappaB inhibitor, pyrrolidine dithiocarbamate, also attenuated IL-1beta-induced PGE(2) release and COX-2 expression. Western blot analysis using PKC isoenzyme-specific antibodies indicated that A549 cells expressed PKC-alpha, -gamma, -iota, -lambda, -zeta, and -micro. IL-1beta caused the translocation of PKC-gamma but not other isoforms from cytosol to the membrane fraction. Moreover, the translocation of PKC-gamma was inhibited by genistein or D-609, but not by U-73122. IL-1beta caused the translocation of p65 NF-kappaB from cytosol to the nucleus as well as the degradation of IkappaB-alpha in cytosol. Furthermore, the translocation of p65 NF-kappaB was inhibited by genistein, Go 6976, Ro 31-8220, or pyrrolidine dithiocarbamate. These results indicate that in human pulmonary epithelial cells, IL-1beta might activate phosphatidylcholine-phospholipase C through an upstream tyrosine phosphorylation to elicit PKC activation, which in turn initiates NF-kappaB activation, and finally induces COX-2 expression and PGE(2) release. Of the PKC isoforms present in A549 cells, only activation of PKC-gamma is involved in regulating IL-1beta-induced responses.
Lin
C H
CH
Graduate Institutes of Biomedical Technology, Taipei Medical College, Taipei, Taiwan. chlin@tmc.edu.tw
Sheu
S Y
SY
Lee
H M
HM
Ho
Y S
YS
Lee
W S
WS
Ko
W C
WC
Sheu
J R
JR
D051546:Cyclooxygenase 2; D015232:Dinoprostone / Q000378:metabolism; D004790:Enzyme Induction; D004847:Epithelial Cells / Q000201:enzymology / Q000378:metabolism; D006801:Humans; D007375:Interleukin-1 / Q000378:metabolism*; D007527:Isoenzymes / Q000096:biosynthesis* / Q000378:metabolism*; D008168:Lung / Q000166:cytology / Q000201:enzymology*; D008565:Membrane Proteins; D016328:NF-kappa B / Q000378:metabolism; D010739:Phospholipase D / Q000378:metabolism; D011451:Prostaglandin-Endoperoxide Synthases / Q000096:biosynthesis*; D011493:Protein Kinase C / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D015398:Signal Transduction; D014407:Tumor Cells, Cultured; D010738:Type C Phospholipases / Q000378:metabolism
D007375:Interleukin-1; D007527:Isoenzymes; D008565:Membrane Proteins; D016328:NF-kappa B; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; C087857:protein kinase C gamma; D011505:Protein-Tyrosine Kinases; D011493:Protein Kinase C; D010738:Type C Phospholipases; D010739:Phospholipase D; D015232:Dinoprostone