Glutathione mediates LPS-stimulated COX-2 expression via early transient p42/44 MAPK activation.
This study examines whether endotoxin (LPS)-stimulated COX-2 is modulated by an interaction between mitogen activated protein kinases (MAPK) and intracellular glutathione. Bovine pulmonary artery endothelial cells (BPAEC) were pretreated for 30 min with the following prior to addition of 0.1 microg/ml endotoxin in 2% FBS in medium 199: 5 mM N-acetylcysteine (NAC) or 5 mM glutathione ethyl ester (GSE) (modulators of intracellular glutathione); 10 microM SB203580 or 25 microM PD98059 (inhibitors of p38 and p42/44 MAPKs, respectively). End-points included assessment of COX-1 and COX-2 gene expression by reverse transcription polymerase chain reaction (RT-PCR); COX-1, COX-2, p38, and p42/44 protein by Western analysis; and measurement of PGE2 and 6-keto-PGF1alpha releases by GC/MS. Both GSE and NAC resulted in significant exacerbation of the LPS-stimulated increase in COX-2 gene and protein expression and prostaglandin release, and suppressed the LPS-induced decrease in COX-1. LPS caused a biphasic activation of p42/44 MAPKs, an early increase peaking at 30 min and a second sustained phase, lasting up to 24 h; LPS also caused an early and sustained increase p38 MAPK activity. Pretreatment of cells with either GSE or NAC increased the early LPS-stimulated activation of p42/44 but had little effect on the sustained phase. Inhibition of either p38 or p42/44 MAPKs suppressed LPS-stimulated COX-2 gene and protein expression, and prostaglandin release (P<0.05) but had little effect on COX-1. We conclude that intracellular glutathione modulates LPS-stimulated COX-2 gene expression and prostaglandin synthesis in BPAEC via early activation of p42/44 MAPKs.
Chen
Jian-Xiong
JX
Department of Pathology, Vanderbilt University Medical Center, Center for Lung Research, Nashville, Tennessee 37232-2650, USA.
Berry
Leonard C
LC
Christman
Brian W
BW
Meyrick
Barbara
B
D000111:Acetylcysteine / Q000494:pharmacology; D000818:Animals; D015153:Blotting, Western; D002417:Cattle; D002478:Cells, Cultured; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D004789:Enzyme Activation / Q000187:drug effects / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D016166:Free Radical Scavengers / Q000494:pharmacology; D015870:Gene Expression / Q000187:drug effects; D005978:Glutathione / Q000031:analogs & derivatives* / Q000378:metabolism* / Q000494:pharmacology; D007527:Isoenzymes / Q000096:biosynthesis* / Q000187:drug effects / Q000235:genetics; D008070:Lipopolysaccharides / Q000494:pharmacology; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000187:drug effects / Q000378:metabolism*; D011451:Prostaglandin-Endoperoxide Synthases / Q000096:biosynthesis* / Q000187:drug effects / Q000235:genetics; D011453:Prostaglandins / Q000378:metabolism; D011651:Pulmonary Artery / Q000166:cytology; D011837:Radiation-Protective Agents / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors; D048051:p38 Mitogen-Activated Protein Kinases
D004791:Enzyme Inhibitors; D016166:Free Radical Scavengers; D007527:Isoenzymes; D008070:Lipopolysaccharides; D011453:Prostaglandins; D011837:Radiation-Protective Agents; C042431:S-ethyl glutathione; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; D011451:Prostaglandin-Endoperoxide Synthases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D005978:Glutathione; D000111:Acetylcysteine