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The study of progesterone action in human myometrial explants

Georgiou, E.X.; Lei, K.; Lai, P.F.; Yulia, A.; Herbert, B.R.; Castellanos, Marcos; May, Sean; Sooranna, S.R.; Johnson, M.R.


E.X. Georgiou

K. Lei

P.F. Lai

A. Yulia

B.R. Herbert

Marcos Castellanos

S.R. Sooranna

M.R. Johnson


Study hypothesis: Myometrial explants represent a superior model compared with cell culture models for the study of human myometrial progesterone (P4) signalling in parturition.
Study finding: Gene expression analysis showed myometrial explants closely resemble the in vivo condition and the anti-inflammatory action of P4 is not lost with labour onset.
What is known already: Circulating P4 levels decline before the onset of parturition in most animals, but not in humans. This has led to the suggestion that there is a functional withdrawal of P4 action at the myometrial level prior to labour onset. However, to date, no evidence of a loss of P4 function has been provided, with studies hampered by a lack of a physiologically relevant model.
Study design, samples/materials, methods: Myometrial biopsies obtained at Caesarean section were dissected into explants after a portion was immediately snap frozen (t = 0). Microarray analysis was used to compare gene expression of t = 0 with paired (i) explants, (ii) passage 4 myometrial cell cultures or (iii) the hTERT myometrial cell line. Western blotting and chemokine/cytokine assays were used to study P4 signalling in myometrial explants.
Main results and the role of chance: Gene expression comparison of t = 0 to the three models demonstrated that explants more closely resemble the in vivo status. At the protein level, explants maintain both P4 receptor (PR) and glucocorticoid receptor (GR) levels versus t = 0 whereas cells only maintain GR levels. Additionally, treatment with 1 μM P4 led to a reduction in interleukin-1 (IL-1) β-driven cyclooxygenase-2 in explants but not in cells. P4 signalling in explants was PR-mediated and associated with a repression of p65 and c-Jun phosphorylation. Furthermore, the anti-inflammatory action of P4 was maintained after labour onset.
Limitations/reasons for caution: There is evidence of basal inflammation in the myometrial explant model.
Wider implications of the findings: Myometrial explants constitute a novel model to study P4 signalling in the myometrium and can be used to further elucidate the mechanisms of P4 action in human labour.
Large scale data: Data deposited at


Georgiou, E., Lei, K., Lai, P., Yulia, A., Herbert, B., Castellanos, M., …Johnson, M. (in press). The study of progesterone action in human myometrial explants. Molecular Human Reproduction, 22(8),

Journal Article Type Article
Acceptance Date May 20, 2016
Online Publication Date May 26, 2016
Deposit Date Nov 28, 2016
Publicly Available Date Nov 28, 2016
Journal Molecular Human Reproduction
Print ISSN 1360-9947
Electronic ISSN 1460-2407
Publisher Oxford University Press
Peer Reviewed Peer Reviewed
Volume 22
Issue 8
Keywords Progesterone Withdrawal, Nuclear Receptors, Myometrial Explants, Smooth Muscle, Parturition, Myometrial Cells, hTERT
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Copyright Statement Copyright information regarding this work can be found at the following address:
Additional Information This is a pre-copy-editing, author-produced PDF of an article accepted for publication in Molecular Human Reproduction following peer review. The definitive publisher-authenticated version E. X. Georgiou, K. Lei, P. F. Lai, A. Yulia, B. R. Herbert, M. Castellanos, S.T. May, S. R. Sooranna, and M. R. Johnson The study of progesterone action in human myometrial explants Mol. Hum. Reprod. first published online May 26, 2016 doi:10.1093/molehr/gaw037 is available online at:


Explant Manuscript.pdf (366 Kb)

Copyright Statement
Copyright information regarding this work can be found at the following address:

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