Induction of cyclooxygenase-2 protein by lipoteichoic acid from Staphylococcus aureus in human pulmonary epithelial cells: involvement of a nuclear factor-kappa B-dependent pathway.
1. This study investigated the role of protein kinase C (PKC) and transcription factor nuclear factor-kappaB (NF-kappaB) in cyclooxygenase-2 (COX-2) expression caused by lipoteichoic acid (LTA), a cell wall component of the gram-positive bacterium Staphylococcus aureus, in human pulmonary epithelial cell line (A549). 2. LTA caused dose- and time-dependent increases in COX-2 expression and COX activity, and a dose-dependent increase in PGE(2) release in A549 cells. The LTA-induced increases in COX-2 expression and COX activity were markedly inhibited by dexamethasone, actinomycin D or cyclohexamide, but not by polymyxin B, which binds and inactivates endotoxin. 3. The phosphatidylcholine-phospholipase C (PC-PLC) inhibitor (D-609) and the phosphatidate phosphohydrolase inhibitor (propranolol) reduced the LTA-induced increases in COX-2 expression and COX activity, while phosphatidylinositol-phospholipase C inhibitor (U-73122) had no effect. The PKC inhibitors (Go 6976, Ro 31-8220 and GF 109203X) and NF-kappaB inhibitor, pyrrolidine dithiocarbamate (PDTC), also attenuated the LTA-induced increases in COX-2 expression and COX activity. 4. Treatment of A549 cells with LTA caused an increase in PKC activity in the plasma membrane; this stimulatory effect was inhibited by D-609, propranolol, or Go 6976, but not by U-73122. 5. Exposure of A549 cells to LTA caused a translocation of p65 NF-kappaB from the cytosol to the nucleus and a degradation of IkappaB-alpha in the cytosol. Treatment of A549 cells with LTA caused NF-kappaB activation by detecting the formation of NF-kappaB-specific DNA-protein complex in the nucleus; this effect was inhibited by dexamethasone, D-609, propranolol, Go 6976, Ro 31-8220, or PDTC. 6. These results suggest that LTA might activate PC-PLC and phosphatidylcholine-phospholipase D to induce PKC activation, which in turn initiates NF-kappaB activation, and finally induces COX-2 expression and PGE(2) release in human pulmonary epithelial cell line.
Lin
C H
CH
Graduate Institute of Biomedical Technology, Taipei Medical University, Taipei, Taiwan. chlin@tmu.edu.tw
Kuan
I H
IH
Lee
H M
HM
Lee
W S
WS
Sheu
J R
JR
Ho
Y S
YS
Wang
C H
CH
Kuo
H P
HP
D051546:Cyclooxygenase 2; D015232:Dinoprostone / Q000096:biosynthesis; D004305:Dose-Response Relationship, Drug; D004847:Epithelial Cells / Q000187:drug effects* / Q000201:enzymology* / Q000382:microbiology; D006801:Humans; D007527:Isoenzymes / Q000096:biosynthesis*; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008168:Lung / Q000166:cytology / Q000187:drug effects / Q000201:enzymology* / Q000502:physiology; D008565:Membrane Proteins; D016328:NF-kappa B / Q000096:biosynthesis*; D011451:Prostaglandin-Endoperoxide Synthases / Q000096:biosynthesis*; D015398:Signal Transduction / Q000187:drug effects* / Q000502:physiology; D013211:Staphylococcus aureus; D013682:Teichoic Acids / Q000494:pharmacology*; D014407:Tumor Cells, Cultured
D007527:Isoenzymes; D008070:Lipopolysaccharides; D008565:Membrane Proteins; D016328:NF-kappa B; D013682:Teichoic Acids; C009900:lipoteichoic acid; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; D015232:Dinoprostone