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Induction of cyclooxygenase‐2 protein by lipoteichoic acid from Staphylococcus aureus in human pulmonary epithelial cells: involvement of a nuclear factor‐κB‐dependent pathway
Author(s) -
Lin ChienHuang,
Kuan IHui,
Lee HorngMo,
Lee WenSen,
Sheu JoenRong,
Ho YuanSoon,
Wang ChunHua,
Kuo HanPin
Publication year - 2001
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1038/sj.bjp.0704290
Subject(s) - lipoteichoic acid , a549 cell , protein kinase c , cyclooxygenase , microbiology and biotechnology , biology , biochemistry , signal transduction , pharmacology , cell , staphylococcus aureus , enzyme , bacteria , genetics
This study investigated the role of protein kinase C (PKC) and transcription factor nuclear factor‐κB (NF‐κB) 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). 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. 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‐κB inhibitor, pyrrolidine dithiocarbamate (PDTC), also attenuated the LTA‐induced increases in COX‐2 expression and COX activity. 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. Exposure of A549 cells to LTA caused a translocation of p65 NF‐κB from the cytosol to the nucleus and a degradation of IκB‐α in the cytosol. Treatment of A549 cells with LTA caused NF‐κB activation by detecting the formation of NF‐κB‐specific DNA‐protein complex in the nucleus; this effect was inhibited by dexamethasone, D‐609, propranolol, Go 6976, Ro 31‐8220, or PDTC. These results suggest that LTA might activate PC‐PLC and phosphatidylcholine‐phospholipase D to induce PKC activation, which in turn initiates NF‐κB activation, and finally induces COX‐2 expression and PGE 2 release in human pulmonary epithelial cell line.British Journal of Pharmacology (2001) 134 , 543–552; doi: 10.1038/sj.bjp.0704290