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Lv X, Gao K, Nie J, Zhang X, Zhang S, Ren Y, Sun X, Li Q, Huang J, Liu L, Zhang X, Zhang W, Liu X. Structures of human prostaglandin F 2α receptor reveal the mechanism of ligand and G protein selectivity. Nat Commun 2023; 14:8136. [PMID: 38065938 PMCID: PMC10709307 DOI: 10.1038/s41467-023-43922-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Accepted: 11/23/2023] [Indexed: 12/18/2023] Open
Abstract
Prostaglandins and their receptors regulate various physiological processes. Carboprost, an analog of prostaglandin F2α and an agonist for the prostaglandin F2-alpha receptor (FP receptor), is clinically used to treat postpartum hemorrhage (PPH). However, off-target activation of closely related receptors such as the prostaglandin E receptor subtype EP3 (EP3 receptor) by carboprost results in side effects and limits the clinical application. Meanwhile, the FP receptor selective agonist latanoprost is not suitable to treat PPH due to its poor solubility and fast clearance. Here, we present two cryo-EM structures of the FP receptor bound to carboprost and latanoprost-FA (the free acid form of latanoprost) at 2.7 Å and 3.2 Å resolution, respectively. The structures reveal the molecular mechanism of FP receptor selectivity for both endogenous prostaglandins and clinical drugs, as well as the molecular mechanism of G protein coupling preference by the prostaglandin receptors. The structural information may guide the development of better prostaglandin drugs.
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Affiliation(s)
- Xiuqing Lv
- Department of Obstetrics, Xiangya Hospital Central South University, Changsha, China
| | - Kaixuan Gao
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Pharmaceutical Sciences, Tsinghua University, Beijing, China
- Beijing Frontier Research Center for Biological Structure, Beijing Advanced Innovation Center for Structural Biology, Tsinghua University, Beijing, China
| | - Jia Nie
- Department of Obstetrics, Xiangya Hospital Central South University, Changsha, China
| | - Xin Zhang
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Pharmaceutical Sciences, Tsinghua University, Beijing, China
- Beijing Frontier Research Center for Biological Structure, Beijing Advanced Innovation Center for Structural Biology, Tsinghua University, Beijing, China
| | - Shuhao Zhang
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Pharmaceutical Sciences, Tsinghua University, Beijing, China
- Beijing Frontier Research Center for Biological Structure, Beijing Advanced Innovation Center for Structural Biology, Tsinghua University, Beijing, China
| | - Yinhang Ren
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Pharmaceutical Sciences, Tsinghua University, Beijing, China
- Beijing Frontier Research Center for Biological Structure, Beijing Advanced Innovation Center for Structural Biology, Tsinghua University, Beijing, China
| | - Xiaoou Sun
- Beijing Frontier Research Center for Biological Structure, Beijing Advanced Innovation Center for Structural Biology, Tsinghua University, Beijing, China
- School of Medicine, Tsinghua University, Beijing, China
| | - Qi Li
- Reproductive Medicine Center, Xiangya Hospital Central South University, Changsha, China
| | - Jingrui Huang
- Department of Obstetrics, Xiangya Hospital Central South University, Changsha, China
| | - Lijuan Liu
- Department of Obstetrics, Xiangya Hospital Central South University, Changsha, China
| | - Xiaowen Zhang
- Department of Obstetrics, Xiangya Hospital Central South University, Changsha, China
| | - Weishe Zhang
- Department of Obstetrics, Xiangya Hospital Central South University, Changsha, China.
- Hunan Engineering Research Center of Early Life Development and Disease Prevention, Changsha, China.
| | - Xiangyu Liu
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Pharmaceutical Sciences, Tsinghua University, Beijing, China.
- Beijing Frontier Research Center for Biological Structure, Beijing Advanced Innovation Center for Structural Biology, Tsinghua University, Beijing, China.
- Beijing Key Laboratory of Cardiovascular Receptors Research, Peking University, Beijing, China.
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Wiebe M, Pfarrer C, Martín LG, Schmicke M, Hoedemaker M, Bollwein H, Heppelmann M. Effect of metritis on in-vitro uterine contractility in cows during the puerperium. Anim Reprod Sci 2022; 239:106971. [PMID: 35339982 DOI: 10.1016/j.anireprosci.2022.106971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 03/15/2022] [Accepted: 03/20/2022] [Indexed: 11/29/2022]
Abstract
Aim of this study was to determine the effect of metritis on in-vitro uterine contractility. Uteri obtained from 16 euthanized Holstein-Friesian cows were divided into two groups depending on whether metritis was absent (M-, n = 6) or present (M+, n = 10). Four longitudinal and four circular myometrial strips of all uteri were incubated in an organ bath. Spontaneous contractility was recorded in five consecutive 30-minute periods (T1-T5). This was followed by stimulation of one longitudinal and one circular strip with increasing concentrations of oxytocin, prostaglandinF2α (PGF2α), and calcium chloride (each during four 30-minute periods [T6-T9]). Strips in group M+ had higher minimum amplitude (minA) values at T1 and higher minA, mean amplitude (meanA), and area under the curve (AUC) values at T2 than strips in group M- (P ≤ 0.05). In the M+ group, the maximum amplitude (maxA), meanA, and AUC values of circular strips were higher than those of longitudinal strips during spontaneous contractility (T1, T4, and T5; P ≤ 0.05). The minA, meanA, and AUC values for strips in group M+ were higher than those in group M- when exposed to the highest concentration of PGF2α (P ≤ 0.05). During stimulation with PGF2α (T9), longitudinal strips had higher maxA values than the circular strips in group M+ (P ≤ 0.05). Spontaneous and stimulated contractility were temporarily increased in uteri with metritis compared to healthy uteri. Both myometrial layers, especially in uteri with metritis, reacted differently during spontaneous contractility and to stimulation with PGF2α.
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Affiliation(s)
- M Wiebe
- Clinic for Cattle, University of Veterinary Medicine Hannover, Foundation, Bischofsholer Damm 15, 30173, Germany.
| | - C Pfarrer
- Institute of Anatomy, University of Veterinary Medicine Hannover, Foundation, Bischofsholer Damm 15, 30173, Germany
| | - L Górriz Martín
- Clinic for Cattle, University of Veterinary Medicine Hannover, Foundation, Bischofsholer Damm 15, 30173, Germany
| | - M Schmicke
- Institute of Agricultural and Nutritional Science, Martin Luther University Halle-Wittenberg, Karl-Freiherr-von-Fritsch-Str. 4, 06120 Halle, Germany
| | - M Hoedemaker
- Clinic for Cattle, University of Veterinary Medicine Hannover, Foundation, Bischofsholer Damm 15, 30173, Germany
| | - H Bollwein
- Clinic for Animal Reproduction Medicine, University of Zurich, Winterthurerstrasse 260, CH-8057 Zurich, Switzerland
| | - M Heppelmann
- Clinic for Cattle, University of Veterinary Medicine Hannover, Foundation, Bischofsholer Damm 15, 30173, Germany
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Leimert KB, Xu W, Princ MM, Chemtob S, Olson DM. Inflammatory Amplification: A Central Tenet of Uterine Transition for Labor. Front Cell Infect Microbiol 2021; 11:660983. [PMID: 34490133 PMCID: PMC8417473 DOI: 10.3389/fcimb.2021.660983] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Accepted: 06/30/2021] [Indexed: 11/23/2022] Open
Abstract
In preparation for delivery, the uterus transitions from actively maintaining quiescence during pregnancy to an active parturient state. This transition occurs as a result of the accumulation of pro-inflammatory signals which are amplified by positive feedback interactions involving paracrine and autocrine signaling at the level of each intrauterine cell and tissue. The amplification events occur in parallel until they reach a certain threshold, ‘tipping the scale’ and contributing to processes of uterine activation and functional progesterone withdrawal. The described signaling interactions all occur upstream from the presentation of clinical labor symptoms. In this review, we will: 1) describe the different physiological processes involved in uterine transition for each intrauterine tissue; 2) compare and contrast the current models of labor initiation; 3) introduce innovative models for measuring paracrine inflammatory interactions; and 4) discuss the therapeutic value in identifying and targeting key players in this crucial event for preterm birth.
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Affiliation(s)
- Kelycia B Leimert
- Department of Obstetrics and Gynecology, University of Alberta, Edmonton, AB, Canada
| | - Wendy Xu
- Department of Obstetrics and Gynecology, University of Alberta, Edmonton, AB, Canada
| | - Magdalena M Princ
- Department of Obstetrics and Gynecology, University of Alberta, Edmonton, AB, Canada
| | - Sylvain Chemtob
- Department of Pediatrics, Ophthalmology and Pharmacology, CHU Sainte-Justine Research Center, Montreal, QC, Canada
| | - David M Olson
- Department of Obstetrics and Gynecology, University of Alberta, Edmonton, AB, Canada
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Pohl O, Marchand L, Gotteland JP, Coates S, Täubel J, Lorch U. Pharmacokinetics, safety and tolerability of OBE022, a selective prostaglandin F2α receptor antagonist tocolytic: A first-in-human trial in healthy postmenopausal women. Br J Clin Pharmacol 2018; 84:1839-1855. [PMID: 29708281 DOI: 10.1111/bcp.13622] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Revised: 04/18/2018] [Accepted: 04/22/2018] [Indexed: 11/28/2022] Open
Abstract
AIMS Preterm birth remains a significant risk for later disability. The selective inhibition of the prostaglandin F2α receptor has significant advantages for a tocolytic. The prodrug OBE022 and its metabolite OBE002 are novel prostaglandin F2α receptor antagonists under development for treating preterm labour. METHODS We performed a prospective, first in human, Phase I, dose escalation, placebo-controlled, randomized trial at a clinical trial site in the UK. Placebo, single ascending doses of 10, 30, 100, 300, 1000 or 1300 mg, and multiple ascending doses over 7 days of 100, 300 or 1000 mg day-1 ; were administered to postmenopausal female volunteers. Food interaction was additionally evaluated. RESULTS Subjects tolerated OBE022 well at all single and multiple doses. No clinically relevant changes in safety parameters were shown and there were no serious adverse events. Observations showed that prodrug OBE022 was readily absorbed and rapidly converted into its equally active stable metabolite OBE002. The plasma level of OBE002 rose with increasing doses, reaching exposure levels that were anticipated to be clinically relevant within 1 h following administration. There was no clinically significant food interaction, with peak exposures reduced to 80% and area under the curve staying bioequivalent. The mean half-life of OBE002 ranged between 8 and 11 h following administration of a single dose and 22-29 h after multiple doses. CONCLUSIONS Administration of OBE022 was safe and had favourable pharmacokinetic characteristics and no clinically relevant interaction with food. Our results allow further investigation of OBE022 in preterm labour patients.
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Affiliation(s)
| | | | | | - Simon Coates
- Richmond Pharmacology Ltd., St George's University of London, London, UK
| | - Jörg Täubel
- Richmond Pharmacology Ltd., St George's University of London, London, UK.,St George's University of London, Cranmer Terrace, London, UK
| | - Ulrike Lorch
- Richmond Pharmacology Ltd., St George's University of London, London, UK
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Anadol E, Kanca H, Yar AS, Helvacioğlu F, Menevşe S, Calgüner E, Erdoğan D. Prostaglandin F receptor expression in intrauterine tissues of pregnant rats. J Vet Sci 2013; 15:125-31. [PMID: 24136214 PMCID: PMC3973755 DOI: 10.4142/jvs.2014.15.1.125] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Accepted: 10/06/2013] [Indexed: 11/20/2022] Open
Abstract
In this investigation, we studied the expression and localization of rat prostaglandin F (FP) receptor in uterine tissues of rats on gestational Days 10, 15, 18, 20, 21, 21.5 and postpartal Days 1 and 3 using Western blotting analysis, real-time PCR, and immunohistochemistry. A high level of immunoreactivity was observed on gestational Days 20, 21, and 21.5 with the most significant signals found on Day 20. FP receptor protein was expressed starting on gestational Day 15, and a fluctuating unsteady increase was observed until delivery. Uterine FP receptor mRNA levels were low between Days 10 and 18 of gestation (p < 0.05). The transcript level increased significantly on Day 20 and peaked on Day 21.5 just before labor (p < 0.05). There was a positive correlation between FP receptor mRNA expression and serum estradiol levels (rs = 0.78; p < 0.01) along with serum estradiol/progesterone ratios (rs = 0.79; p < 0.01). In summary, we observed an increase FP receptor expression in rat uterus with advancing gestation, a marked elevation of expression at term, and a concominant decrease during the postpartum period. These findings indicate a role for uterine FP receptors in the mediation of uterine contractility at term.
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Affiliation(s)
- Elvan Anadol
- Laboratory Animals Breeding and Experimental Research Center, Gazi University, Ankara 06510 ,
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Evaluation of genes involved in prostaglandin action in equine endometrium during estrous cycle and early pregnancy. Anim Reprod Sci 2010; 122:124-32. [DOI: 10.1016/j.anireprosci.2010.08.007] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2010] [Revised: 07/23/2010] [Accepted: 08/05/2010] [Indexed: 11/22/2022]
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Gogny A, Mallem Y, Destrumelle S, Thorin C, Desfontis JC, Gogny M, Fiéni F. In vitro comparison of myometrial contractility induced by aglepristone-oxytocin and aglepristone-PGF2alpha combinations at different stages of the estrus cycle in the bitch. Theriogenology 2010; 74:1531-8. [PMID: 20708231 DOI: 10.1016/j.theriogenology.2010.06.023] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2010] [Revised: 06/04/2010] [Accepted: 06/21/2010] [Indexed: 11/25/2022]
Abstract
The aim of this in vitro study was to compare the uterokinetic activity of oxytocin and dinoprost, the natural PGF2α, with or without aglepristone, in canine myometrial fibers. Thirty-three bitches were allocated into one of four groups, depending on their estrous stage and whether or not they had received a treatment with aglepristone (metestrus aglepristone, n = 5; metestrus without treatment, n = 9; anestrus aglepristone, n = 9; anestrus without treatment, n = 10). After hysterectomy, longitudinal and circular uterine strips were mounted in organ baths. Oxytocin or PGF2α (10 nmol/l to 10 micromol/l) were applied non-cumulatively. A linear mixed effects models theory was used to compare the fiber effect, the aglepristone effect, and the treatment effect, from the area under the curves calculated from the contractile effect/concentration curves for each drug. Oxytocin and PGF2α induced concentration-dependent myometrial contractions in longitudinal (LF) and circular myometrial fibers (CF), indicating the presence of functional contractile oxytocin- and PGF2α-receptors in metestrus and anestrus. The contractile response to oxytocin was greater in LF than in CF in all of the groups; the response to PGF2α was greater in LF than in CF in non-treated bitches in anestrus and in treated bitches in metestrus. These results suggest that there is a difference in sensitivity or a heterogeneous distribution of oxytocin and PGF2α-receptors in the myometrial layers, which is independent of hormonal impregnation. The contractile response to oxytocin and PGF2α was significantly increased after aglepristone treatment in LF during metestrus, suggesting that the progesterone withdrawal induced by aglepristone has a role to play. The longitudinal myometrial layer also appeared to be the target for the two drugs at this stage. This study provides new information about canine uterine contractile activity, notably the differing behavior of myometrial CF and LF; in vivo studies are required to test the use of a combination of aglepristone and oxytocin in the treatment of canine pyometra.
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Affiliation(s)
- A Gogny
- Laboratory of Biotechnology and Pathology of Reproduction, Nantes-Atlantic National College of Veterinary Medicine, Food Science and Engineering-ONIRIS, F-44307 Nantes, France.
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Arthur P, Taggart MJ, Zielnik B, Wong S, Mitchell BF. Relationship between gene expression and function of uterotonic systems in the rat during gestation, uterine activation and both term and preterm labour. J Physiol 2008; 586:6063-76. [PMID: 18936075 DOI: 10.1113/jphysiol.2008.164004] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
We have documented gestation- and labour- (preterm and term) dependent changes in expression of genes encoding contraction associated proteins in the rat uterus and correlated these changes with various parameters of uterine contractility. The data demonstrate increased expression of contractile agonist systems concurrent with decreased expression of relaxant systems after gestational day 20. Significant increases in expression of oxytocin (OT), its receptor (OTR), prostaglandin (PG) H synthase isoform 1 (PGHS-1) and PGF(2alpha) receptor (FP) occurred first, followed by increases in PGHS-2, connexin-43, endothelin-1 (ET-1) and the ET-1 receptor isoform ET(A). Expression of OTR and FP was significantly reduced during mid-gestation compared to non-pregnant animals. Expression of inducible nitric oxide synthase (iNOS) increased significantly during pregnancy then decreased concurrently with the increase in OTR and FP. Functional changes in uterine contractility accompany changes in gene expression. OT was the most potent contractile stimulant. Sensitivity of uterine strips to OT was reduced in early and mid-pregnancy then increased at uterine activation. Progesterone antagonist-induced preterm labour caused changes similar to those at normal term. Comparison of mRNA transcripts in separated endometrium and myometrium suggested that the endometrium is an important regulator of myometrial contractility, analogous to the relationship between endothelium and vascular smooth muscle. This novel combination of functional and genetic expression analyses provides new insight into the physiology of parturition.
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Affiliation(s)
- Patrice Arthur
- Perinatal Research Centre, Department of Obstetrics and Gynaecology, 220 Heritage Medical Research Centre, University of Alberta, Edmonton, Alberta, Canada T6G 2S2
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Zannoni A, Bernardini C, Rada T, Ribeiro LA, Forni M, Bacci ML. Prostaglandin F2-alpha receptor (FPr) expression on porcine corpus luteum microvascular endothelial cells (pCL-MVECs). Reprod Biol Endocrinol 2007; 5:31. [PMID: 17659079 PMCID: PMC1949401 DOI: 10.1186/1477-7827-5-31] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2007] [Accepted: 07/20/2007] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND The corpus luteum (CL) is a transient endocrine gland and prostaglandin F2-alpha is considered to be the principal luteolysin in pigs. In this species, the in vivo administration of prostaglandin F2-alpha induces apoptosis in large vessels as early as 6 hours after administration. The presence of the prostaglandin F2-alpha receptor (FPr) on the microvascular endothelial cells (pCL-MVECs) of the porcine corpus luteum has not yet been defined. The aim of the study was to assess FPr expression in pCL-MVECs in the early and mid-luteal phases (EL-p, ML-p), and during pregnancy (P-p). Moreover, the effectiveness of prostaglandin F2-alpha treatment in inducing pCL-MVEC apoptosis was tested. METHODS Porcine CLs were collected in the EL and ML phases and during P-p. All CLs from each animal were minced together and the homogenates underwent enzymatic digestion. The pCL-MVECs were then positively selected by an immunomagnetic separation protocol using Dynabeads coated with anti-CD31 monoclonal antibody and seeded in flasks in the presence of EGM 2-MV (Microvascular Endothelial Cell Medium-2). After 4 days of culture, the cells underwent additional immunomagnetic selection and were seeded in flasks until the confluent stage.PCR Real time, western blot and immunodetection assays were utilized to assess the presence of FPr on pCL-MVEC primary cultures. Furthermore, the influence of culture time (freshly isolated, cultured overnight and at confluence) and hormonal treatment (P4 and E2) on FPr expression in pCL-MVECs was also investigated. Apoptosis was detected by TUNEL assay of pCL-MVECs exposed to prostaglandin F2-alpha. RESULTS We obtained primary cultures of pCL-MVECs from all animals. FPr mRNA and protein levels showed the highest value (ANOVA) in CL-MVECs derived from the early-luteal phase. Moreover, freshly isolated MVECs showed a higher FPr mRNA value than those cultured overnight and confluent cells (ANOVA). prostaglandin F2-alpha treatment failed to induce an apoptotic response in all the pCL-MVEC cultures. CONCLUSION Our data showing the presence of FPr on MVECs and the inability of prostaglandin F2-alpha to evoke an in vitro apoptotic response suggest that other molecules or mechanisms must be considered in order to explain the in vivo direct pro-apoptotic effect of prostaglandin F2-alpha at the endothelial level.
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Affiliation(s)
- Augusta Zannoni
- Department of Veterinary Morphophysiology and Animal Production, DIMORFIPA, Ozzano Emilia 40064, University of Bologna, Italy
| | - Chiara Bernardini
- Department of Veterinary Morphophysiology and Animal Production, DIMORFIPA, Ozzano Emilia 40064, University of Bologna, Italy
| | - Tommaso Rada
- Department of Polymer Engineering, University of Minho 4710-057 Braga, Portugal
| | - Luciana A Ribeiro
- Department of Veterinary Morphophysiology and Animal Production, DIMORFIPA, Ozzano Emilia 40064, University of Bologna, Italy
| | - Monica Forni
- Department of Veterinary Morphophysiology and Animal Production, DIMORFIPA, Ozzano Emilia 40064, University of Bologna, Italy
| | - Maria L Bacci
- Department of Veterinary Morphophysiology and Animal Production, DIMORFIPA, Ozzano Emilia 40064, University of Bologna, Italy
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Cirillo R, Tos EG, Page P, Missotten M, Quattropani A, Scheer A, Schwarz MK, Chollet A. Arrest of preterm labor in rat and mouse by an oral and selective nonprostanoid antagonist of the prostaglandin F2alpha receptor (FP). Am J Obstet Gynecol 2007; 197:54.e1-9. [PMID: 17618756 DOI: 10.1016/j.ajog.2007.02.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2006] [Revised: 11/30/2006] [Accepted: 02/15/2007] [Indexed: 10/23/2022]
Abstract
OBJECTIVE The purpose of this study was to assess the tocolytic effect of AS604872, an orally active, potent, and selective prostanoid prostaglandin F2alpha receptor (FP) antagonist. STUDY DESIGN Compound AS604872 was characterized and tested for its ability to block uterine contraction and delay preterm parturition in rodent models. RESULTS AS604872 inhibited spontaneous uterine contractions in pregnant rat near term. In pregnant mouse, AS604872 delayed parturition induced by either the antiprogesterone RU-486 or the endotoxin lipopolysaccharide. Pups from treated mothers were delivered alive. The efficacy of AS604872 was superior to the beta-mimetic drug ritodrine. Combination of AS604872 and ritodrine showed an additive inhibitory effect on spontaneous uterine contractions in rat. CONCLUSION A selective antagonist of the FP receptor suppresses uterine contractility and delays labor. Our findings identify a new potential modality for the pharmacological management of preterm labor.
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Affiliation(s)
- Rocco Cirillo
- Istituto di Ricerche Biomediche A. Marxer. Merck Serono, Colleretto Giacosa, Italy
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11
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Chollet A, Tos EG, Cirillo R. Tocolytic effect of a selective FP receptor antagonist in rodent models reveals an innovative approach to the treatment of preterm labor. BMC Pregnancy Childbirth 2007; 7 Suppl 1:S16. [PMID: 17570160 PMCID: PMC1892057 DOI: 10.1186/1471-2393-7-s1-s16] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Background Management of preterm labor by tocolysis remains an unmet medical need. Prostaglandins play a major role in regulation of uterine activity and in molecular mechanisms of human labor and parturition. There is some circumstantial evidence that prostaglandin F2α by action through the prostaglandin receptor subtype FP is effective in key events during labor uterine contraction, rupture of membranes and cervical dilation. This role of FP is briefly reviewed. In this study, we tested the hypothesis that an orally active and selective FP antagonist may arrest labor and delay parturition in animal models. Methods We examined the effects of a small molecule selective antagonist of the FP receptor (AS604872) in inhibition of spontaneous uterine contraction in pregnant rat near term. We tested AS604872 for its ability to delay preterm birth in a mouse model in which the anti-progestin agent RU486 triggered parturition. Results By oral or intravenous dosing AS604872 reduced markedly and dose-dependently the spontaneous uterine contractions in late-term pregnant rats at gestational days 19–21. In pregnant mice, AS604872 delayed the preterm birth caused by RU486 administration. The effect was dose-dependent with a significant increase in the mean delivery time of 16 and 33 hours at oral doses of 30 mg/kg and 100 mg/kg, respectively, in the case of labor triggered at gestational day 14. In both models AS604872 appeared more effective than the β-agonist ritodrine. Conclusion The tocolytic activity displayed by a selective FP receptor antagonist supports a key role for the FP receptor in the pathophysiology of premature birth and demonstrates the therapeutic potential of an FP antagonist for the treatment of preterm labor cases in which uterine hyperactivity plays a dominant role.
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Wehbrink D, Hässig M, Ritter N, Zerbe H, Bleul U, Boos A. Immunohistochemical demonstration of cyclooxygenase-2 (COX-2) and prostaglandin receptors EP2 and FP expression in the bovine intercaruncular uterine wall around term. Anim Reprod Sci 2007; 106:241-54. [PMID: 17574782 DOI: 10.1016/j.anireprosci.2007.04.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2006] [Revised: 04/12/2007] [Accepted: 04/24/2007] [Indexed: 01/19/2023]
Abstract
During parturition, uterine-derived prostaglandins (PG) play an outstanding role regarding the functional elimination of the corpus luteum and the promotion of uterine contraction. The rate-limiting enzyme cyclooxygenase-2 (COX-2), highly regulated in a cell-type and localization specific manner throughout pregnancy, is involved in uterine prostanoid production. Prostaglandins exert their effects via G-protein-coupled receptors. Distribution and cellular localization of these receptors are decisive factors for prostaglandin-mediated actions. Since both COX-2 and PG receptors have only been assessed during pregnancy in the cow, these parameters were localized immunohistochemically near term to evaluate their specific role at parturition. Thus, during two periods, segments of the intercaruncular uterine wall were collected from cows at slaughter being eight and nine months pregnant, from cattle during caesarean section, and after spontaneous calving. Results reveal that COX-2 was mainly localized in the cytoplasm of surface epithelial cells with a high expression in animals with induced parturition. The enzyme could also be found in lower concentrations within the glandular epithelium without any effect of gestational time or labour. In contrast to relaxant prostaglandin E receptor type 2 (EP2), not showing any change in all tissue layers observed, contractile prostaglandin F(2alpha) receptor (FP) was modulated during the peripartal period revealing a peak expression in animals with induced parturition. FP was localized in surface and glandular epithelial cells as well as in endometrial stroma and myometrial smooth muscle cells. Our study indicates that labour and induction of parturition may have an effect on amounts of immunohistochemically detectable COX-2 and FP. EP2 remains rather unchanged during the peripartal period. COX-2 and FP thus contribute via changes in amount and distribution to mechanisms associated with parturition.
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Affiliation(s)
- D Wehbrink
- Institute of Veterinary Anatomy, Vetsuisse Faculty, University of Zurich, Winterthurerstrasse 260, CH-8057 Zurich, Switzerland
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Grigsby PL, Sooranna SR, Adu-Amankwa B, Pitzer B, Brockman DE, Johnson MR, Myatt L. Regional Expression of Prostaglandin E2 and F2alpha Receptors in Human Myometrium, Amnion, and Choriodecidua with Advancing Gestation and Labor1. Biol Reprod 2006; 75:297-305. [PMID: 16707767 DOI: 10.1095/biolreprod.106.051987] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
The change from uterine quiescence to enhanced contractile activity may be due to the differential expression of prostaglandin receptors within the myometrium and fetal membranes, in a temporal and topographically distinct manner. To address this question, we determined the localization and expression of the PGE2 receptor subtypes (PTGER1-4) and the PGF2alpha receptor (PTGFR) in paired upper and lower segment myometrium, amnion, and choriodecidual samples throughout human pregnancy, with and without labor. All receptor subtypes were found throughout the muscle layers in both the upper and lower uterine segments, colocalizing with alpha smooth muscle actin. A change in intracellular localization was observed at term labor, where PTGER1 and PTGER4 were predominately associated with the nucleus. Minimal changes in the expression of the PGE2 and PGF2alpha receptor subtypes were observed with gestational age, labor, or between the upper and lower myometrial segments. Receptor expression in maternal and fetal tissues differed between the receptor subtypes; PTGER1 and PTGER4 were predominately expressed in the fetal membranes, PTGER2 was greatest in the myometrium, whereas PTGER3 and PTGFR were similarly expressed in the myometrium and fetal membranes. Myometrial activation through the prostaglandin receptors is perhaps more subtle and may be mediated by a balance between one or several of the prostaglandin receptor subtypes together with other known contraction associated proteins. Lack of coordination in receptor expression between the myometrium and fetal membranes may indicate different regulatory mechanisms between these tissues, or it may suggest a function for these receptors in the amnion and choriodecidua that is independent of that seen in the myometrium.
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MESH Headings
- Amnion/physiology
- Chorion/physiology
- Decidua/physiology
- Female
- Gene Expression Regulation, Developmental
- Gestational Age
- Humans
- Labor, Obstetric
- Myometrium/physiology
- Obstetric Labor, Premature
- Polymerase Chain Reaction/methods
- Pregnancy
- Receptors, Prostaglandin/genetics
- Receptors, Prostaglandin/metabolism
- Receptors, Prostaglandin E/genetics
- Receptors, Prostaglandin E/metabolism
- Receptors, Prostaglandin E, EP1 Subtype
- Receptors, Prostaglandin E, EP2 Subtype
- Receptors, Prostaglandin E, EP3 Subtype
- Receptors, Prostaglandin E, EP4 Subtype
- Uterine Contraction/physiology
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Affiliation(s)
- Peta L Grigsby
- Department of Obstetrics and Gynecology, University of Cincinnati, Medical College, Cincinnati, Ohio 45267, USA.
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Döring B, Shynlova O, Tsui P, Eckardt D, Janssen-Bienhold U, Hofmann F, Feil S, Feil R, Lye SJ, Willecke K. Ablation of connexin43 in uterine smooth muscle cells of the mouse causes delayed parturition. J Cell Sci 2006; 119:1715-22. [PMID: 16595547 DOI: 10.1242/jcs.02892] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Gap junctions are characteristically increased in the myometrium during term and preterm delivery and are thought to be essential for the development of uterine contractions during labour. Expression of connexin43 (Cx43), the major myometrial gap junction protein, is increased during delivery. We have generated a mouse mutant (Cx43fl/fl:SM-CreERT2), in which the coding region of Cx43 can be specifically deleted in smooth muscle cells at any given time point by application of tamoxifen. By this approach, we were able to study long-term effects on myometrial functions that are necessary for parturition as well as gap junction intercellular communication in primary myometrial cell cultures. We found a prolongation of the pregnancy in 82% of tamoxifen-treated Cx43fl/fl:SM-CreERT2 mice as well as decreased dye coupling in cultured primary myocytes of these animals. Other parturition-specific parameters such as the regulation of oxytocin receptor, prostaglandin F receptor or progesterone remained unchanged. Our results indicate the important function of Cx43 during parturition in the living animal and suggest further strategies to investigate the role of connexins in uterine contractility in transgenic mice.
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Affiliation(s)
- Britta Döring
- Institut für Genetik, Abteilung Molekulargenetik, Universität Bonn, Römerstr. 164, 53117 Bonn, Germany
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15
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Sooranna SR, Grigsby P, Myatt L, Bennett PR, Johnson MR. Prostanoid receptors in human uterine myocytes: the effect of reproductive state and stretch. Mol Hum Reprod 2006; 11:859-64. [PMID: 16421214 DOI: 10.1093/molehr/gah228] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In the human, prostanoids are known to be important mediators of uterine relaxation and contraction during pregnancy and parturition. We have previously shown that stretch of uterine smooth muscle cells increased prostaglandin H synthase 2 (PGHS-2) mRNA expression, PGHS-2 peptide synthesis and activity, however, the net effect on uterine contractility of this increase in prostaglandin synthesis would be determined by the expression of the different prostanoid receptors. Therefore, the aims of this study were to establish the expression of prostanoid receptor mRNA in uterine myocytes obtained from women in different reproductive states and to test the hypothesis that stretch of uterine myocytes alters prostanoid receptor mRNA expression to promote uterine contractility. Myocytes were isolated from women undergoing hysterectomy (NP) and pregnant women undergoing LSCS either before (NL) or after the onset of labour (L) and were subjected to 11% stretch for 1 h (n = 6 in all cases). Copy numbers of the individual receptors varied widely with reproductive state but followed the pattern: FP > IP = DP = EP-4 > TP = EP-3 = EP-2 > EP-1. FP mRNA expression was significantly lower in the NL group compared to the NP group and EP-3, EP-4 and TP mRNA expression was significantly lower in both NL and L groups compared to NP group levels. The level of mRNA expression of EP-1, EP-2, DP and IP did not differ between NP, NL and L groups. Stretch of cells derived from the NP group resulted in a significant decrease in EP-4 mRNA expression alone and of the NL group a significant decrease in EP-2 mRNA expression alone. Stretch had no effect on cells derived from the L group. These data show that pregnancy is associated with a significant reduction in 3 of 4 pro-contraction associated prostanoid receptor mRNA expression and 1 of 4 pro-relaxant. Stretch elicited no consistent change in prostanoid receptor mRNA expression.
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Affiliation(s)
- S R Sooranna
- Imperial College Parturition Research Group, Department of Maternal Fetal Medicine, Imperial College School of Medicine, Chelsea and Westminster Hospital, London, UK
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16
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Mitchell BF, Zielnik B, Wong S, Roberts CD, Mitchell JM. Intraperitoneal infusion of proinflammatory cytokines does not cause activation of the rat uterus during late gestation. Am J Physiol Endocrinol Metab 2005; 289:E658-64. [PMID: 15870103 DOI: 10.1152/ajpendo.00058.2005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Increased concentrations of IL-1beta and TNF-alpha have been associated with parturition. However, the role of these cytokines is unknown. Before parturition, the uterus undergoes a process of activation, during which there are significant changes in expression of genes associated with increased uterine contractility, including the receptors for oxytocin (OT) and prostaglandin (PG)F(2alpha) (FP), PGH(2) synthase isoform 2 (PGHS2), the gap junction protein connexin-43 (Cx-43), and the inducible isoform of nitric oxide synthase (iNOS). To determine whether IL-1beta or TNF-alpha was part of the causal mechanism for increased uterine contractions, we placed osmotic pumps infusing IL-1beta or TNF-alpha into the peritoneal cavity of late pregnant rats (gestation day 19) and measured the effects on uterine contractility and on the uterine concentrations of mRNA for the contraction-associated genes 24 h later. Maternal serum concentrations of IL-1beta and TNF-alpha were increased significantly. By day 21, the control animals had significant increases (P < or = 0.05) in mRNA for OT, FP, PGHS2, and Cx-43, a decrease (P < or = 0.05) in iNOS, and an increase (P < or = 0.05) in uterine sensitivity and responsiveness to OT. Infusion of IL-1beta or TNF-alpha had no effect on uterine contractility or on expression of the activation-associated genes. We conclude that intraperitoneal infusion of IL-1beta or TNF-alpha resulting in significantly increased maternal serum cytokine levels does not cause uterine activation. The role of proinflammatory cytokines in the mechanism of parturition remains unclear.
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Affiliation(s)
- Bryan F Mitchell
- Perinatal Research Centre, University of Alberta, Edmonton, Alberta, Canada T6G 2S2.
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17
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Affiliation(s)
- Grant S Frazer
- College of Veterinary Medicine, The Ohio State University, A100 Sisson Hall, 1920 Coffey Road, Columbus, OH 43210, USA.
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Hirst JJ, Parkington HC, Young IR, Palliser HK, Peri KG, Olson DM. Delay of preterm birth in sheep by THG113.31, a prostaglandin F2alpha receptor antagonist. Am J Obstet Gynecol 2005; 193:256-66. [PMID: 16021088 DOI: 10.1016/j.ajog.2004.11.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
OBJECTIVE A novel prostaglandin F2alpha receptor antagonist, THG113.31, was tested for the suppression of uterine contractility and delay of preterm labor in sheep. STUDY DESIGN We determined the tocolytic effectiveness of THG113.31 on contractions that were stimulated in vitro by prostaglandin F2alpha and E2 in longitudinal and circular myometrial strips. We also tested the ability of THG113.31 in vivo to lower uterine electromyographic activity that was induced by the progesterone receptor blocker, RU486, and to delay preterm birth. RESULTS THG113.31 suppressed the amplitude of prostaglandin F2alpha, but not prostaglandin E2-induced contractions of both circular and longitudinal myometrium (P<.01). The times to delivery after RU486 were 34.8+/-1.1 hours (saline solution) and 41.9+/-0.5 hours (THG113.31; P<.001) or an average delay of 7.1 hours. There were no changes in fetal blood gases (PaO2 , PaCO2 , pH, or SaO2) because of THG113.31. Fetal cortisol levels rose in each group, and fetal and maternal prostaglandin E2 and F2alpha metabolite concentrations rose similarly in both groups. CONCLUSION THG113.31 specifically suppresses prostaglandin F2alpha-induced myometrial contractility and delays delivery.
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Affiliation(s)
- Jonathan J Hirst
- Department of Physiology, Monash University, Clayton, Victoria, Australia
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19
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Astle S, Thornton S, Slater DM. Identification and localization of prostaglandin E2 receptors in upper and lower segment human myometrium during pregnancy. Mol Hum Reprod 2005; 11:279-87. [PMID: 15722440 DOI: 10.1093/molehr/gah158] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Prostaglandin E2 (PGE2) plays a key role in the maintenance of human pregnancy and labour onset. PGE2 can elicit diverse actions within the uterus depending on the PGE2 receptors (EP1, EP2, EP3 and EP4) expressed. By signalling through different intracellular pathways the EP receptors may inhibit or promote smooth muscle contractility. Nine different EP3 receptor splice variants have been identified with divergent signalling pathways. RT-PCR and immunohistochemistry were utilized to identify and localize EP receptor isoforms within the upper segment (US) and lower segment (LS) myometrium. EP1 was significantly increased in the LS myometrium with term labour. EP3 (and EP3 splice variants EP3I(1b), EP3II, EP3III and EP3IV) was down-regulated in pregnancy (US and/or LS) with a further decrease at term labour in the LS. Overall, expression of EP2 was significantly higher in the LS while EP3 was significantly higher in the US. No significant EP4 changes were observed. Consistent with the RT-PCR results, immunohistochemistry confirmed the presence and, interestingly, showed nuclear localization of EP receptors in the myometrium with higher EP1 expression and lower expression of EP3. The differential regulation of EP receptors within the myometrium indicates that they may play a role in controlling the onset and maintenance of human labour.
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Affiliation(s)
- Shirley Astle
- Biomedical Research Institute, Department of Biological Sciences, University of Warwick, Coventry CV4 7AL, UK.
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20
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Georgescu A, Popov D. The contractile response of the mesenteric resistance arteries to prostaglandin F2alpha; effects of simultaneous hyperlipemia-diabetes. Fundam Clin Pharmacol 2004; 17:683-9. [PMID: 15015713 DOI: 10.1046/j.1472-8206.2003.00196.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The effect of hyperlipemia associated with diabetes on the contractility of resistance arteries to prostaglandin F2alpha (PGF2alpha) was investigated employing 4 weeks simultaneously hyperlipemic-diabetic (HD), hyperlipemic (H), diabetic (D) and normal hamsters (controls, C). The isometric force produced by explanted arteries in the presence of 10(-8) to 10(-5) M PGF2alpha was recorded by the myograph technique. The results showed that compared with controls, the contractile response to 10(-5) M PGF2alpha was approx. 2 fold increased in HD group, and approx. 1.75 and 1.62-fold enhanced in H and D groups, respectively. Activation of protein kinase C with 10(-6) M phorbol 12-myristate 13-acetate increased the contractility to PGF2alpha in all groups and particularly in HD hamsters (approx. 10.16-fold). Inhibition of cyclooxygenase by indomethacin increased approx. 1.81-fold the arterial contractility to PGF2alpha in C group, whereas in H, D and HD hamsters had no effect. Blockage of Ca(2+)-activated K(+)-channels with 10(-3) M tetraethylammonium augmented the contraction to PGF2alpha approx. 6.43-fold in C group, and at significantly lower levels in H, D and HD groups, i.e. approx. 3.84, 3.72 and 3.33-fold, respectively. The results validate two conclusions: (i) simultaneous insult of hyperlipemia-hyperglycemia is associated with the highest contractility of the resistance arteries to PGF2alpha; the highest circulating glucose and cholesterol levels, and the enhancement in the protein kinase C pathway underlay the augmented contractility; (ii) no matter the pathology induced (hyperlipemia, diabetes or both simultaneously) a common dysfunctional response to PGF2alpha was installed; this consists in a reduced effect of cyclooxygenase inhibition, and a altered activity of Ca(2+) dependent K(+) channels.
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Affiliation(s)
- Adriana Georgescu
- Institute of Cellular Biology and Pathology Nicolae Simionescu, 8, B.P. Hasdeu Street, PO Box 35-14, Ro-79691, Bucharest, Romania
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21
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Myatt L, Lye SJ. Expression, localization and function of prostaglandin receptors in myometrium. Prostaglandins Leukot Essent Fatty Acids 2004; 70:137-48. [PMID: 14683689 DOI: 10.1016/j.plefa.2003.04.004] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Prostaglandins (PGs) play a role in the initiation and maintenance of labor, acting via specific relaxatory or contractile receptors on myometrium. Myometrial response to addition of PGs may be determined by the type and concentration of receptor expressed. Autoradiographic and ligand binding studies suggest a topographic distribution of receptors between fundus, lower segment, and cervix, and that hormonally regulated changes in expression occur with advancing gestation and labor. These receptors have now been cloned and sequenced allowing molecular studies. Current dogma suggests functional regionalization of the pregnant human uterus occurs with the lower segment displaying a contractile phenotype throughout gestation changing to a relaxatory phenotype at labor to allow passage of the fetal head whereas the upper segment has a relaxatory phenotype throughout most of gestation to accommodate the growing fetus and adopts a contractile phenotype for expulsion at labor. Studies to determine the role of PG receptors in this phenomenon are currently underway.
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Affiliation(s)
- Leslie Myatt
- Deparment of Obstetrics and Gynecology, College of Medicine, University of Cincinnati, PO Box 670526, Cincinnati, OH 45267, USA.
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22
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Ansari HR, Kaddour-Djebbar I, Abdel-Latif AA. Effects of prostaglandin F2α, latanoprost and carbachol on phosphoinositide turnover, MAP kinases, myosin light chain phosphorylation and contraction and functional existence and expression of FP receptors in bovine iris sphincter. Exp Eye Res 2004; 78:285-96. [PMID: 14729360 DOI: 10.1016/j.exer.2003.10.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A potential role for myosin light chain kinase (MLCK) in regulating intraocular pressure and outflow function has recently been reported in living monkey eye and rabbit eye. There is little information about the effects of the ocular hypotensive agents, prostaglandin F2alpha (PGF2alpha) and latanoprost on this signaling pathway in ocular tissues. The aim of this study was to determine the agonist activity of PGF2alpha, latanoprost and carbachol (CCh) on the MLCK pathway in isolated bovine iris sphincter and furthermore to investigate the existence of the FP receptor in this tissue. In the present studies on the MLCK pathway four signal transduction mechanism assays were employed, phosphoinositide (PI) turnover, p42/p44 MAP kinase phosphorylation and activation, MLC phosphorylation and contraction. In the studies on the existence of the FP receptor in the bovine iris sphincter, the pharmacology and expression of the FP receptor protein, using a polyclonal anti-FP-receptor antibody and Western blot analysis, were determined. The data obtained on the MLCK pathway showed that the three agonists stimulated the biochemical and pharmacological responses in a concentration and time-dependent manner and that the order of potency and efficacy is PGF2alpha>latanoprost>CCh. The EC50 values in the PI turnover, MAP kinase phosphorylation, MLC phosphorylation and contraction assays were for PGF2alpha: 9, 42, 200 and 140 nM, respectively, for latanoprost: 13, 59, 250 and 828 nM, respectively, and for CCh: 22, 200, 630 and 910 nM, respectively. Wortmannin, a selective inhibitor of MLCK, dose-dependently inhibited MLC phosphorylation and contraction induced by PGF2alpha, demonstrating a close relationship between activation of the MLCK pathway and contraction. The pharmacological studies showed that in the concentration range of 1 nM to 10 microM, the FP-receptor agonists caused concentration-response curves with the following order of potencies: 17-phenyl trinor PGF2alpha (bimatoprost acid)>PGF2alpha>cloprostenol>latanoprost>latanoprost acid>bimatoprost amide>>fluprostenol. Immunoblot analysis of the FP receptor demonstrated expression of the prostaglandin FP receptor protein in this smooth muscle. These results clearly indicate that the MLCK signaling pathway is involved in the FP-receptor function of the bovine iris sphincter and furthermore demonstrate that functional FP receptors exist and are expressed in this tissue.
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Affiliation(s)
- Habib R Ansari
- Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta, GA 30912, USA
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Leonhardt A, Glaser A, Wegmann M, Hackenberg R, Nüsing RM. Expression of prostanoid receptors in human lower segment pregnant myometrium. Prostaglandins Leukot Essent Fatty Acids 2003; 69:307-13. [PMID: 14580364 DOI: 10.1016/s0952-3278(03)00113-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Prostanoids, especially prostaglandin (PG) E(2), are important mediators of uterine relaxation and contractions during gestation and parturition. Inhibitors of PG formation as well as PG analogues are used to modulate uterine tonus. So far, only limited data are available regarding the expression of prostanoid receptors in human pregnant myometrium. In the present study, the expression of the receptors for PGE(2) (EP1, EP2, EP3, EP4), PGF(2alpha) (FP), prostacyclin (IP), and thromboxane A(2) (TP) in human pregnant myometrium was studied by RT-PCR, in situ hybridization and immunohistochemistry. Myometrial tissue was obtained from five women at term and not in labour and from two women who delivered preterm. Tissue specimens were excised from the upper edge of the transverse lower uterine segment incision. In all tissues analysed, EP1, EP2, EP3, EP4, FP, TP and IP receptor mRNA and protein was detected. mRNA expression for PGD(2) (DP) receptor was not detected in the majority of tissue specimens. EP1, EP2, EP4, IP, TP and FP receptor protein was detected on myometrial smooth muscle cells, whereas EP3 receptor protein was only expressed by stromal and endothelial cells. In situ hybridization experiments yielded similar results. The expression of the EP2 receptor mRNA was inversely related to gestational age. We suggest that the contractile effect of PGE(2) at term is probably mediated directly by the EP1 receptor expressed in myometrial smooth muscle cells and indirectly by the EP3 receptor expressed in stromal cells and a decrease in EP2 receptor expression.
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Affiliation(s)
- Andreas Leonhardt
- Department of Pediatrics, Philipp's University, Deutschhausstr. 12, Marburg 35033, Germany
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Condon JC, Jeyasuria P, Faust JM, Wilson JW, Mendelson CR. A decline in the levels of progesterone receptor coactivators in the pregnant uterus at term may antagonize progesterone receptor function and contribute to the initiation of parturition. Proc Natl Acad Sci U S A 2003; 100:9518-23. [PMID: 12886011 PMCID: PMC170950 DOI: 10.1073/pnas.1633616100] [Citation(s) in RCA: 224] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2003] [Indexed: 11/18/2022] Open
Abstract
The molecular events that lead to the onset of labor in humans and in other mammalian species remain unclear. We propose that a decline in coactivators containing histone acetylase activity in myometrium may contribute to the onset of labor by impairing the function of the progesterone-progesterone receptor (PR) complex. As assessed by semiquantitative and real-time RT-PCR, immunohistochemistry, and immunoblotting, expression of the PR coactivators cAMP-response element-binding protein (CREB)-binding protein and steroid receptor coactivators 2 and 3 was decreased in fundal uterine tissue of women in labor. Using the mouse as an animal model, we also found decreased coactivator levels in uterine tissues at term. In both human and mouse, the levels of acetylated histone H3 were also decreased in uterine tissues at term. Administration of trichostatin A, a specific and potent histone deacetylase inhibitor, to pregnant mice late in gestation increased histone acetylation and delayed the initiation of parturition by 24-48 h, suggesting the functional importance of the decline in histone acetylation in the initiation of labor. These findings suggest that the decline in PR coactivator expression and in histone acetylation in the uterus near term may impair PR function by causing a functional progesterone withdrawal. The resulting decrease in expression of PR-responsive genes should increase sensitivity of the uterus to contractile stimuli.
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Affiliation(s)
- Jennifer C Condon
- Department of Biochemistry, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9038, USA
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25
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Abstract
Labour at term and preterm results from activation and then stimulation of the myometrium. Activation can occur through mechanical stretch of the uterus, and by endocrine pathways resulting from increased activity of the fetal hypothalamic-pituitary-adrenal axis. In women and in experimental animals, cortisol likely contributes to increased prostaglandin production in fetal tissues through up-regulation of the type 2 prostaglandin H2, synthase-2 (PGHS-2) and down-regulation of 15-OH prostaglandin dehydrogenase. Cortisol increases expression of prostaglandin dehydrogenase in the chorion by reversing the stimulatory effect of progesterone, and may represent "progesterone withdrawal" in the primate. By competing with progesterone inhibition, cortisol also increases expression of placental corticotropin-releasing hormone. Other agents, such as pro-inflammatory cytokines, similarly up-regulate PGHS-2 and decrease expression of prostaglandin dehydrogenase. Oxytocin, produced locally within the intrauterine tissues, is also thought to be involved in parturition, and there is a marked increase in oxytocin receptor expression at term. There are thus several mechanisms by which labour at term or preterm may be initiated. These different mechanisms need to be considered in the development of strategies for the detection and management of women in preterm labour. Ongoing studies are investigating the use of oxytocin receptor antagonists, PGHS-2 inhibitors, and nitric oxide to prevent or regulate preterm labour. The presence of fibronectin in vaginal secretions, and elevated maternal serum levels of corticotropin-releasing hormone, estrogens, and cytokines have been examined as possible markers of preterm labour. However, at the present time, we do not have the ability to accurately predict or diagnose preterm labour, nor do we have specific or efficient methods to inhibit labour once it has started.
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Affiliation(s)
- W Gibb
- Department of Obstetrics and Gynaecology, and Cellular and Molecular Medicine, University of Ottawa; Ottawa Hospital Research Institute, Ottawa, ON, Canada
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