Molecular evidence of functional progesterone withdrawal in human myometrium.
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ABSTRACT:
SUBMITTER: Nadeem L
PROVIDER: S-EPMC4894948 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Background and objectivesCervix remodeling (CRM) is a critical process in preparation for parturition. Early cervix shortening is a powerful clinical predictor of preterm birth, and thus understanding how CRM is regulated is important for the prevention of prematurity. Humans and other primates differ from most other mammals by the maintenance of high levels of systemic progesterone concentrations. Humans have been hypothesized to perform functional progesterone withdrawal (FPW). Guinea pigs are similar to humans in maintaining high-progesterone concentrations through parturition, thus making them a prime model for studying CRM. Here, we analyze the phylogenetic history of FPW and document gene expression in the guinea pig uterine cervix.MethodologyData on progesterone withdrawal were collected from the literature, and character evolution was analyzed. Uterine cervix samples were collected from non-pregnant, mid-pregnant and late pregnant guinea pigs. RNA was extracted and sequenced. Relative transcript levels were estimated and compared among sample groups.ResultsThe phylogenetic analysis shows that FPW evolved independently in primates and guinea pigs. The transcriptome data confirms that guinea pigs down-regulate progesterone receptor toward parturition, in contrast to humans. Some of the similarities between human and guinea pig are: down-regulation of estrogen receptor, up-regulation of VCAN and IGFBP4 as well as likely involvement of prostaglandins.Conclusions and implications(i) FPW in guinea pigs evolved independently from that in primates. (ii) A small set of conserved gene regulatory changes has been detected.
| S-EPMC3875370 | biostudies-literature
Project description:Cervix remodeling (CRM) is a critical process in preparation for parturition. Early cervix shortening is a powerful clinical predictor of preterm birth, and thus understanding how CRM is regulated is important for the prevention of prematurity. Humans and other primates differ from most other mammals by the maintenance of high levels of systemic progesterone concentrations and thus differ dramatically from most model species. Humans have been hypothesized to perform functional progesterone withdrawal (FPW), but the mechanisms of FPW are not known. Guinea pigs are similar to humans as they also maintain high progesterone concentrations through parturition. The aim of this study is to document gene expression during pregnancy in the guinea pig uterine cervix in order to assess whether guinea pig can be used as a model for human FPW
2013-12-31 | GSE47986 | GEO
Project description:Cervix remodeling (CRM) is a critical process in preparation for parturition. Early cervix shortening is a powerful clinical predictor of preterm birth, and thus understanding how CRM is regulated is important for the prevention of prematurity. Humans and other primates differ from most other mammals by the maintenance of high levels of systemic progesterone concentrations and thus differ dramatically from most model species. Humans have been hypothesized to perform functional progesterone withdrawal (FPW), but the mechanisms of FPW are not known. Guinea pigs are similar to humans as they also maintain high progesterone concentrations through parturition. The aim of this study is to document gene expression during pregnancy in the guinea pig uterine cervix in order to assess whether guinea pig can be used as a model for human FPW Total RNA obtained from isolated cervical tissues from non-pregnant and two genstation stages (mid-term, and late-term but not in labor).
2013-12-31 | E-GEOD-47986 | biostudies-arrayexpress
Project description:Progesterone withdrawal is essential for parturition, but the mechanism of this pivotal hormonal change is unclear in women and other mammals that give birth without a pre-labor drop in maternal progesterone levels. One possibility suggested by uterine tissue analyses and cell culture models is that progesterone receptor levels change at term decreasing the progesterone responsiveness of the myometrium, which causes progesterone withdrawal at the functional level and results in estrogen dominance enhancing uterine contractility. In this investigation we have explored whether receptor mediated functional progesterone withdrawal occurs during late pregnancy and labor in vivo. We have also determined whether prostaglandins that induce labor cause functional progesterone withdrawal by altering myometrial progesterone receptor expression. Pregnant guinea pigs were used, since this animal loses progesterone responsiveness at term and gives birth in the presence of high maternal progesterone level similarly to primates. We found that progesterone receptor mRNA and protein A and B expression decreased in the guinea pig uterus during the last third of gestation and in labor. Prostaglandin administration reduced while prostaglandin synthesis inhibitor treatment increased progesterone receptor A protein abundance. Estrogen receptor-1 protein levels remained unchanged during late gestation, in labor and after prostaglandin or prostaglandin synthesis inhibitor administration. Steroid receptor levels were higher in the non-pregnant than in the pregnant uterine horns. We conclude that the decreasing expression of both progesterone receptors A and B is a physiological mechanism of functional progesterone withdrawal in the guinea pig during late pregnancy and in labor. Further, prostaglandins administered exogenously or produced endogenously stimulate labor in part by suppressing uterine progesterone receptor A expression, which may cause functional progesterone withdrawal, promote estrogen dominance and foster myometrial contractions.
| S-EPMC4144885 | biostudies-literature
Project description:Recently, it has been suggested that progesterone affects the contractile activity of pregnant myometrium via nongenomic pathways; therefore, we aimed to clarify whether progesterone causes and/or inhibits pregnant myometrial contractions via nongenomic pathways. Our in vitro experiments using myometrial strips obtained from rats at 20 days of gestation revealed that progesterone caused myometrial contractions in a concentration- and time-dependent manner at concentrations up to 5 × 10-7 M; however, this effect decreased at concentrations higher than 5 × 10-5 M. Similarly, progesterone enhanced oxytocin-induced contractions up to 5 × 10-7 M and inhibited contractions at concentrations higher than 5 × 10-5 M. Conversely, progesterone did not enhance high-KCl-induced contractions but inhibited contractions in a concentration- and time-dependent manner at concentrations higher than 5 × 10-7 M. We also found that RU486 did not affect progesterone-induced contractions or the progesterone-induced inhibition of high-KCl-induced contractions; however, progesterone-induced contractions were blocked by calcium-free phosphate saline solution, verapamil, and nifedipine. In addition, FPL64176, an activator of L-type voltage-dependent calcium channels, enhanced high-KCl-induced contractions and rescued the decrease in high-KCl-induced contractions caused by progesterone. Together, these results suggest that progesterone exerts conflicting nongenomic effects on the contractions of pregnant myometrium via putative L-type voltage-dependent calcium channels.
| S-EPMC7926872 | biostudies-literature
Project description:Use of long-acting progestin only contraceptives (LAPCs) offers a discrete and highly effective family planning method. Abnormal uterine bleeding (AUB) is the major side effect of, and cause for, discontinuation of LAPCs. The endometria of LAPC-treated women display abnormally enlarged, fragile blood vessels, decreased endometrial blood flow and oxidative stress. To understanding to mechanisms underlying AUB, we propose to identify LAPC-modulated unique gene cluster(s) in human endometrial stromal cells (HESCs). Protein and RNA isolated from cultured HESCs treated 7 days with estradiol (E2) or E2+ medroxyprogesterone acetate (MPA) or E2+ etonogestrel (ETO) or E2+ progesterone (P4) were analyzed by quantitative Real-time (q)-PCR and immunoblotting. HSCORES were determined for immunostained-paired endometria of pre-and 3 months post-Depot MPA (DMPA) treated women and ovariectomized guinea pigs (GPs) treated with placebo or E2 or MPA or E2+MPA for 21 days. In HESCs, whole genome analysis identified a 67 gene group regulated by all three progestins, whereas a 235 gene group was regulated by E2+ETO and E2+MPA, but not E2+P4. Ingenuity pathway analysis identified glucocorticoid receptor (GR) activation as one of upstream regulators of the 235 MPA and ETO-specific genes. Among these, microarray results demonstrated significant enhancement of FKBP51, a repressor of PR/GR transcriptional activity, by both MPA and ETO. q-PCR and immunoblot analysis confirmed the microarray results. In endometria of post-DMPA versus pre-DMPA administered women, FKBP51 expression was significantly increased in endometrial stromal and glandular cells. In GPs, E2+MPA or MPA significantly increased FKBP51 immunoreactivity in endometrial stromal and glandular cells versus placebo- and E2-administered groups. MPA or ETO administration activates GR signaling and increases endometrial FKBP51 expression, which could be one of the mechanisms causing AUB by inhibiting PR and GR-mediated transcription. The resultant PR and/or GR-mediated functional withdrawal may contribute to associated endometrial inflammation, aberrant angiogenesis, and bleeding.
| S-EPMC4593551 | biostudies-literature
Project description:BACKGROUND: Ghrelin is a 28-amino acid octanolyated peptide, synthesised primarily in the stomach. It stimulates growth hormone release, food intake and exhibits many other diverse effects. Our group have previously determined that ghrelin inhibited human contractility in vitro. The aim of this study therefore, was to investigate the expression of ghrelin, its receptor, the growth hormone secretagogue receptor type 1 (GHS-R1), ghrelin O-acyltransferase (GOAT) which catalyses ghrelin octanoylation, prohormone convertase 1/3 (PC1/3) responsible for pro-ghrelin processing, in human myometrium, during pregnancy prior to labour, during labour and in the non-pregnant state. Modulation of ghrelin and ghrelin receptor expression in cultured myometrial cells was also investigated. METHODS: mRNA and protein were isolated from human myometrium and the myometrial smooth muscle cell line hTERT-HM; and real-time fluorescence RT-PCR, western blotting and fluorescence microscopy performed. The effects of beta-Estradiol and bacterial lipopolysaccharide (LPS) on hTERT-HM gene expression were evaluated by western blotting. RESULTS: We have reported for the first time the expression and processing of ghrelin, GHS-R1, GOAT and PC1/3 expression in human myometrium, and also the down-regulation of ghrelin mRNA and protein expression during labour. Furthermore, GHS-R1 protein expression significantly decreased at labour. Myometrial GOAT expression significantly increased during term non-labouring pregnancy in comparison to both non-pregnant and labouring myometrium. Mature PC1/3 protein expression was significantly decreased at term pregnancy and labour in comparison to non-pregnant myometrium. Ghrelin, GHS-R1, GOAT and PC1/3 mRNA and protein expression was also detected in the hTERT-HM cells. Ghrelin protein expression decreased upon LPS treatment in these cells while beta-Estradiol treatment increased GHS-R1 expression. CONCLUSIONS: Ghrelin processing occurred in the human myometrium at term pregnancy and in the non-pregnant state. GOAT expression which increased during term non-labouring pregnancy demonstrating a similar expression pattern to prepro-ghrelin and GHS-R1, decreased at labour, signifying possible myometrial ghrelin acylation. Moreover, the presence of PC1/3 may contribute to pro-ghrelin processing. These results along with the previous in vitro data suggest that myometrially-produced and processed ghrelin plays a significant autocrine or paracrine role in the maintenance of relaxation in this tissue during pregnancy. Furthermore, the significant uterine modulators LPS and beta-Estradiol are involved in the regulation of ghrelin and ghrelin receptor expression respectively, in the human myometrium.
| S-EPMC2887880 | biostudies-literature
Project description:Progestagenic sex steroid hormones play critical roles in reproduction across vertebrates, including teleost fish. To further our understanding of how progesterone modulates testis functions in fish, we set out to clone a progesterone receptor (pgr) cDNA exhibiting nuclear hormone receptor features from zebrafish testis. The open reading frame of pgr consists of 1854 bp, coding for a 617-amino acid-long protein showing the highest similarity with other piscine Pgr proteins. Functional characterization of the receptor expressed in mammalian cells revealed that zebrafish Pgr exhibited progesterone-specific, dose-dependent induction of reporter gene expression, with 17 alpha,20 beta-dihydroxy-4-pregnen-3-one (DHP), a typical piscine progesterone, showing the highest potency. Expression of pgr mRNA: 1) appeared in embryos at 8 h after fertilization; 2) was significantly higher in developing ovary than in early transforming testis at 4 wk of age but vice versa in young adults at 12 wk of age, and thus resembling the expression pattern of the germ cell marker piwil1; and, 3) was restricted to Leydig and Sertoli cells in adult testis. Zebrafish testicular explants released DHP concentration dependently in response to high concentrations of recombinant zebrafish gonadotropins. In addition, DHP stimulated 11-ketotestosterone release from zebrafish testicular explants, but only in the presence of its immediate precursor, 11 beta-hydroxytestosterone. This stimulatory activity was blocked by a Pgr antagonist (RU486), suggesting that 11 beta-hydroxysteroid dehydrogenase activity was stimulated by DHP via Pgr. Our data suggest that DHP contributes to the regulation of Leydig cell steroidogenesis, and potentially--via Sertoli cells--also to germ cell differentiation in zebrafish testis.
| S-EPMC2802120 | biostudies-literature
Project description:Sperm chemotaxis is a chemical guiding mechanism that may orient spermatozoa to the egg surface. A picomolar concentration gradient of Progesterone (P), the main steroidal component secreted by the cumulus cells that surround the egg, attracts human spermatozoa. In order to elucidate the molecular mechanism of sperm chemotaxis mediated by P, we combine the application of different strategies: pharmacological inhibition of signaling molecules, measurements of the concentrations of second messengers and activation of the chemotactic signaling. Our data implicate a number of classic signal transduction pathways in the response and provide a model for the sequence of events, where the tmAC-cAMP-PKA pathway is activated first, followed by protein tyrosine phosphorylation (equatorial band and flagellum) and calcium mobilization (through IP(3)R and SOC channels), whereas the sGC-cGMP-PKG cascade, is activated later. These events lead to sperm orientation towards the source of the chemoattractant. The finding proposes a molecular mechanism which contributes to the understanding of the signal transduction pathway that takes place in a physiological process as chemotaxis.
| S-EPMC2782141 | biostudies-literature
Project description:BACKGROUND: RHOGTPases play a significant role in modulating myometrial contractility in uterine smooth muscle. They are regulated by at least three families of proteins, RHO guanine nucleotide exchange factors (RHOGEFs), RHOGTPase-activating proteins (RHOGAPs) and RHO guanine nucleotide inhibitors (RHOGDIs). RHOGEFs activate RHOGTPases from the inactive GDP-bound to the active GTP-bound form. RHOGAPs deactivate RHOGTPases by accelerating the intrinsic GTPase activity of the RHOGTPases, converting them from the active to the inactive form. RHOGDIs bind to GDP-bound RHOGTPases and sequester them in the cytosol, thereby inhibiting their activity. Ezrin-Radixin-Moesin (ERM) proteins regulate the cortical actin cytoskeleton, and an ERM protein, moesin (MSN), is activated by and can also activate RHOGTPases. METHODS: We therefore investigated the expression of various RHOGEFs, RHOGAPs, a RHOGDI and MSN in human myometrium, by semi-quantitative reverse transcription PCR, real-time fluorescence RT-PCR, western blotting and immunofluorescence microscopy. Expression of these molecules was also examined in myometrial smooth muscle cells. RESULTS: ARHGEF1, ARHGEF11, ARHGEF12, ARHGAP5, ARHGAP24, ARHGDIA and MSN mRNA and protein expression was confirmed in human myometrium at term pregnancy, at labour and in the non-pregnant state. Furthermore, their expression was detected in myometrial smooth muscle cells. It was determined that ARHGAP24 mRNA expression significantly increased at labour in comparison to the non-labour state. CONCLUSION: This study demonstrated for the first time the expression of the RHOGTPase regulators ARHGEF1, ARHGEF11, ARHGEF12, ARHGAP5, ARHGAP24, ARHGDIA and MSN in human myometrium, at term pregnancy, at labour, in the non-pregnant state and also in myometrial smooth muscle cells. ARHGAP24 mRNA expression significantly increased at labour in comparison to the non-labouring state. Further investigation of these molecules may enable us to further our knowledge of RHOGTPase regulation in human myometrium during pregnancy and labour.
| S-EPMC2254629 | biostudies-literature