The expression of genes involved in myometrial contractility changes during ex situ culture of pregnant human uterine smooth muscle tissue.
BACKGROUND
Ex situ analyses of human myometrial tissue has been used to investigate the regulation of uterine quiescence and transition to a contractile phenotype. Following concerns about the validity of cultured primary cells, we examined whether myometrial tissue undergoes culture-induced changes ex situ that may affect the validity of in vitro models.


OBJECTIVES
To determine whether human myometrial tissue undergoes culture-induced changes ex situ in Estrogen receptor 1 (ESR1), Prostaglandin-endoperoxide synthase 2 (PTGS2) and Oxytocin receptor (OXTR) expression. Additionally, to determine whether culture conditions approaching the in vivo environment influence the expression of these key genes.


METHODS
Term non-laboring human myometrial tissues were cultured in the presence of specific treatments, including; serum supplementation, progesterone and estrogen, cAMP, PMA, stretch or NF-κB inhibitors. ESR1, PTGS2 and OXTR mRNA abundance after 48 h culture was determined using quantitative RT-PCR.


RESULTS
Myometrial tissue in culture exhibited culture-induced up-regulation of ESR1 and PTGS2 and down-regulation of OXTR mRNA expression. Progesterone prevented culture-induced increase in ESR1 expression. Estrogen further up-regulated PTGS2 expression. Stretch had no direct effect, but blocked the effects of progesterone and estrogen on ESR1 and PTGS2 expression. cAMP had no effect whereas PMA further up-regulated PTGS2 expression and prevented decline of OXTR expression.


CONCLUSION
Human myometrial tissue in culture undergoes culture-induced gene expression changes consistent with transition toward a laboring phenotype. Changes in ESR1, PTGS2 and OXTR expression could not be controlled simultaneously. Until optimal culture conditions are determined, results of in vitro experiments with myometrial tissues should be interpreted with caution.
['Ilicic|Marina|M|', 'Butler|Trent|T|', 'Zakar|Tamas|T|', 'Paul|Jonathan W|JW|']
D002478:Cells, Cultured D051546:Cyclooxygenase 2 D015536:Down-Regulation D047628:Estrogen Receptor alpha D004967:Estrogens D005260:Female D015870:Gene Expression D006801:Humans D009130:Muscle, Smooth D011247:Pregnancy D011374:Progesterone D018045:Receptors, Oxytocin D015854:Up-Regulation D014590:Uterine Contraction D014599:Uterus
transition phenotype ESR1 PTGS2 OXTR myometrium