Superinduction of COX-2 mRNA by cycloheximide and interleukin-1beta involves increased transcription and correlates with increased NF-kappaB and JNK activation.
Many primary response genes, including cyclooxygenase-2 (COX-2), exhibit mRNA superinduction following agonist stimulation in the presence of translational blockers such as cycloheximide. This is widely assumed to result from mRNA stabilisation. However, superinduction of IL-1beta-induced COX-2 mRNA levels by cycloheximide in pulmonary type II A549 cells occurred by increased transcription and not by mRNA stabilisation. Furthermore, equivalent effects were observed on NF-kappaB binding to COX-2 promoter kappaB sites and activation of the Jun N-terminal kinases (JNK), p54 and p46. These signalling pathways play important roles in COX-2 induction and may therefore account for the observed increases in COX-2 transcription. These data are consistent with negative feed-back involving down-regulation of NF-kappaB by de novo IkappaB alpha synthesis and suggest that JNK activation may also be down-regulated by a cycloheximide sensitive process.
Newton
R
R
Department of Thoracic Medicine, National Heart and Lung Institute, Imperial College School of Medicine, London, UK. robert.newton@ic.ac.uk
Stevens
D A
DA
Hart
L A
LA
Lindsay
M
M
Adcock
I M
IM
Barnes
P J
PJ
D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D002460:Cell Line; D003513:Cycloheximide / Q000494:pharmacology*; D051546:Cyclooxygenase 2; D003609:Dactinomycin / Q000494:pharmacology; D004789:Enzyme Activation; D004790:Enzyme Induction / Q000187:drug effects; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology*; D007527:Isoenzymes / Q000096:biosynthesis* / Q000235:genetics; D048031:JNK Mitogen-Activated Protein Kinases; D007700:Kinetics; D008168:Lung; D008565:Membrane Proteins; D020928:Mitogen-Activated Protein Kinases; D016328:NF-kappa B / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D011451:Prostaglandin-Endoperoxide Synthases / Q000096:biosynthesis* / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis; D014158:Transcription, Genetic / Q000187:drug effects*; D048051:p38 Mitogen-Activated Protein Kinases
D007375:Interleukin-1; D007527:Isoenzymes; D008565:Membrane Proteins; D016328:NF-kappa B; D012333:RNA, Messenger; D003609:Dactinomycin; D003513:Cycloheximide; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases