Tumour necrosis factor-alpha stimulates increased expression of prostaglandin endoperoxide H synthase Type 2 mRNA in amnion-derived WISH cells.
We have evaluated the mechanism by which tumour necrosis factor-alpha (TNF-alpha) induces increased prostaglandin (PG) biosynthesis in amnion-derived WISH cells. WISH cells were treated with 50 ng/ml TNF-alpha or vehicle for 0-24 h. PGE2 production was stimulated by TNF-alpha within 2 h and continued to accumulate for at least 24 h. Increased prostaglandin endoperoxide H synthase (PGHS)-2 mRNA expression was evident within 30 min and was highest by 1 h, returning to unstimulated levels by 2 h. The PGHS-2 mRNA was re-induced at 8 h and was also elevated at 16 h. Immunoreactive PGHS-2 protein was nearly undetectable in control cells. However, within 30 min of TNF-alpha treatment, PGHS-2 protein was elevated and was induced for at least 16 h suggesting rapid production of both the PGHS-2 mRNA and protein. Transcription run-on assays indicated that the initial increase in the PGHS-2 mRNA was due to a 20-fold increase in the rate of transcription. The PGHS-2 mRNA decayed with an apparent half-life of 1 h in TNF-alpha-stimulated WISH cells. Induction of PGHS-2 expression proceeded in the presence of 10 microg/ml cycloheximide which agrees with the classification of PGHS-2 as an immediate early gene. These results indicate that a bi-phasic induction of the PGHS-2 mRNA is due, in part, to an initial transcriptional activation which results in rapid and continued synthesis of the PGHS-2 protein. This may be a unique characteristic of amnion cells which may be partially responsible for increased PG concentrations in the amniotic fluid during infection-associated preterm labour.
Hansen
W R
WR
Department of Pharmacology and Clinical Pharmacology, The University of Auckland School of Medicine, Grafton, New Zealand.
Sato
T
T
Mitchell
M D
MD
D000650:Amnion / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology; D002460:Cell Line; D015232:Dinoprostone / Q000096:biosynthesis; D015971:Gene Expression Regulation, Enzymologic / Q000235:genetics*; D017781:Genes, Immediate-Early; D006207:Half-Life; D011451:Prostaglandin-Endoperoxide Synthases / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D011451:Prostaglandin-Endoperoxide Synthases; D015232:Dinoprostone