Mechanical stretch activates type 2 cyclooxygenase via activator protein-1 transcription factor in human myometrial cells.
The uterus is subject to stretch throughout pregnancy, which, in the presence of progesterone, is a potent stimulus for uterine growth. However, in the absence of progesterone or when stretch is excessive, as in multiple pregnancy, it may provoke the onset of labour. We have investigated the effect of stretch on prostaglandin synthesis in primary human uterine myocytes [non-pregnant (NP), pregnant not in labour (NL) and pregnant in labour (L)]. The cells were grown on flexible bottom culture plates and subjected to 1 or 6 h static stretch. Expression of type 2 cyclooxygenase (COX-2) mRNA was similar in samples obtained from NP and L groups and both were significantly greater than those found in the NL group. Stretch of cells from all groups resulted in increased COX-2 mRNA expression. In further studies carried out on cells taken from the NL group, 6 h of stretch resulted in increased COX-2 protein levels and, in the media, increases in prostaglandin (PG) I(2) metabolite and PGE(2) concentrations and a reduction in the concentration of PGF(2)alpha metabolites. After stretch, EMSA studies showed increased activator protein-1 (AP-1) nuclear protein DNA binding activity but not of nuclear factor kappaB. These data demonstrate that stretch of human myocytes results in increased COX-2 activity and suggest that this may occur through activation of the AP-1 system.
Sooranna
S R
SR
Department of Maternal Fetal Medicine, Imperial College School of Medicine, Chelsea and Westminster Hospital, 369 Fulham Road, London, SW10 9NH.
Lee
Y
Y
Kim
L U
LU
Mohan
A R
AR
Bennett
P R
PR
Johnson
M R
MR
D000328:Adult; D002478:Cells, Cultured; D051546:Cyclooxygenase 2; D015237:Dinoprost / Q000378:metabolism; D015232:Dinoprostone / Q000378:metabolism; D024202:Electrophoretic Mobility Shift Assay; D004797:Enzyme-Linked Immunosorbent Assay; D011464:Epoprostenol / Q000378:metabolism; D005260:Female; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D007527:Isoenzymes / Q000096:biosynthesis* / Q000235:genetics; D008565:Membrane Proteins; D008875:Middle Aged; D032389:Myocytes, Smooth Muscle / Q000201:enzymology / Q000378:metabolism; D009215:Myometrium / Q000166:cytology / Q000201:enzymology*; D016328:NF-kappa B / Q000378:metabolism; D011247:Pregnancy; D011451:Prostaglandin-Endoperoxide Synthases / Q000096:biosynthesis* / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013314:Stress, Mechanical; D018808:Transcription Factor AP-1 / Q000378:metabolism*; D014590:Uterine Contraction / Q000378:metabolism
D007527:Isoenzymes; D008565:Membrane Proteins; D016328:NF-kappa B; D012333:RNA, Messenger; D018808:Transcription Factor AP-1; D015237:Dinoprost; D011464:Epoprostenol; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; D015232:Dinoprostone