A transmembrane intracellular estrogen receptor mediates rapid cell signaling. Revankar CM et al. (2005) The steroid hormone estrogen regulates many functionally unrelated processes in numerous tissues. Although it is traditionally thought to control transcriptional activation through the classical nuclear estrogen receptors, it also initiates many rapid nongenomic signaling events. We found that of all G protein-coupled receptors characterized to date, GPR30 is uniquely localized to the endoplasmic reticulum, where it specifically binds estrogen and fluorescent estrogen derivatives. Activating GPR30 by estrogen resulted in intracellular calcium mobilization and synthesis of phosphatidylinositol 3,4,5-trisphosphate in the nucleus. Thus, GPR30 represents an intracellular transmembrane estrogen receptor that may contribute to normal estrogen physiology as well as pathophysiology.//////////////////The Catecholestrogen, 2-Hydroxyestradiol-17beta, Acts as a G Protein-Coupled Estrogen Receptor 1 (GPER/GPR30) Antagonist to Promote the Resumption of Meiosis in Zebrafish Oocytes. Chourasia TK et al. (2015) Estradiol-17beta (E2) maintains high cAMP levels and meiotic arrest in zebrafish oocytes through activation of G protein-coupled estrogen receptor, GPER. The catecholestrogen 2-hydroxyestradiol-17beta (2-OHE2) has an opposite effect to that of E2 on oocyte maturation (OM) and cAMP levels in Indian catfish oocytes. We tested the hypothesis that 2-OHE2 is produced in zebrafish ovaries and promotes the resumption of oocyte meiosis through its action as a GPER antagonist. Ovarian 2-OHE2 production by estrogen-2-hydroxylase (EH) was upregulated by gonadotropin treatment at the onset of OM, consistent with a physiological role for 2-OHE2 in regulating OM. The increase in EH activity and OM were blocked by treatment with CYP1A1 and CYP1B1 inhibitors. Expression of cyp1a, cyp1b1 and cyp1c mRNAs was increased by gonadotropin treatment, further implicating these Cyp1s in 2-OHE2 synthesis prior to OM. Conversely, aromatase activity and cyp19a1 mRNA expression declined during gonadotropin induction of OM. 2-OHE2 treatment significantly increased spontaneous OM in defolliculated zebrafish oocytes and reversed the inhibition of OM by E2 and the GPER agonist, G-1. 2-OHE2 was an effective competitor of [(3)H]-E2 binding to recombinant zebrafish GPER expressed in HEK-293 cells. 2-OHE2 also antagonized estrogens actions through GPER on cAMP production in zebrafish oocytes, resulting in a reduction in cAMP levels and resumption of OM. Stimulation of OM by 2-OHE2 was blocked by pretreatment of defolliculated oocytes with the GPER antibody. Collectively the results suggest 2-OHE2 functions as a GPER antagonist and promotes OM in zebrafish through blocking GPER-dependent E2 inhibition of the resumption of OM.//////////////////
NCBI Summary:
This gene encodes a multi-pass membrane protein that localizes to the endoplasmic reticulum and a member of the G-protein coupled receptor 1 family. This receptor binds estrogen and activates multiple downstream signaling pathways, leading to stimulation of adenylate cyclase and an increase in cyclic AMP levels, while also promoting intracellular calcium mobilization and synthesis of phosphatidylinositol 3,4,5-trisphosphate in the nucleus. This protein therefore plays a role in the rapid nongenomic signaling events widely observed following stimulation of cells and tissues with estrogen. This receptor has been shown to play a role in diverse biological processes, including bone and nervous system development, metabolism, cognition, male fertility and uterine function. [provided by RefSeq, Aug 2017]
Membrane Estrogen Receptor (GPER) and Follicle-Stimulating Hormone Receptor (FSHR) Heteromeric Complexes Promote Human Ovarian Follicle Survival. Casarini L et al. (2020) Classically, follicle-stimulating hormone receptor (FSHR)-driven cAMP-mediated signaling boosts human ovarian follicle growth and oocyte maturation. However, contradicting in vitro data suggest a different view on physiological significance of FSHR-mediated cAMP signaling. We found that the G-protein-coupled estrogen receptor (GPER) heteromerizes with FSHR, reprogramming cAMP/death signals into proliferative stimuli fundamental for sustaining oocyte survival. In human granulosa cells, survival signals are missing at high FSHR:GPER ratio, which negatively impacts follicle maturation and strongly correlates with preferential Gαs protein/cAMP-pathway coupling and FSH responsiveness of patients undergoing controlled ovarian stimulation. In contrast, FSHR/GPER heteromers triggered anti-apoptotic/proliferative FSH signaling delivered via the Gβγ dimer, whereas impairment of heteromer formation or GPER knockdown enhanced the FSH-dependent cell death and steroidogenesis. Therefore, our findings indicate how oocyte maturation depends on the capability of GPER to shape FSHR selective signals, indicating hormone receptor heteromers may be a marker of cell proliferation.//////////////////
Mechanisms of estradiol-induced EGF-like factor expression and oocyte maturation via G protein-coupled estrogen receptor. Zhang H et al. (2020) Estrogen is an important modulator of reproductive activity through nuclear receptors and G protein-coupled estrogen receptor (GPER). Here, we observed that both estradiol and the GPER-specific agonist G1 rapidly induced cAMP production in cumulus cells, leading to transient stimulation of phosphorylated cAMP response element binding protein (CREB), which was conducive to the transcription of epidermal growth factor (EGF)-like factors, amphiregulin, epiregulin, and betacellulin. Inhibition of GPER by G15 significantly reduced estradiol-induced CREB phosphorylation and EGF-like factor gene expression. Consistently, the silencing of GPER expression in cultured cumulus cells abrogated the estradiol-induced CREB phosphorylation and EGF-like factor transcription. In addition, the increase in EGF-like factor expression in the cumulus cells is associated with EGFR tyrosine kinase phosphorylation and extracellular signal-regulated kinase 1/2 (ERK1/2) activation. Furthermore, we demonstrated that GPER-mediated phosphorylation of EGFR and ERK1/2 was involved in reduced gap junction communication, cumulus expansion, increased oocyte mitochondrial activity and first polar body (PBΙ) extrusion. Overall, our study identified a novel function for estrogen in regulating EGFR activation via GPER in cumulus cells during oocyte maturation.//////////////////
Effect of FSH on E2/GPR30-mediated mouse oocyte maturation in vitro. Zhao H et al. (2019) Mammalian oocyte restores meiosis can be stimulated by follicle-stimulating hormone (FSH) under normal physiological conditions. G-protein coupled receptor 30 (GPR30), an non-classical estrogen membrane receptor, has been widely reported in teleost oocyte maturation. However, it remains unknown whether GPR30 involves the role of FSH in mammalian cumulus expansion and oocyte maturation. Here, we used mouse cumulus-oocyte complexes (COCs) as a model to investigate how FSH affects the in vitro maturation of mouse oocytes mediated by 17β-estradiol (E2)/GPR30signaling. Our study reveals that FSH starts regulating mouse cumulus expansion precisely at 8h in in vitro culture. ELISA measurement of E2 levels in culture medium revealed that FSH activated aromatase to promote E2 production in vitro in cultured mouse COCs. Moreover, the results of real-time quantitative PCR indicated that FSH-induced in vitro maturation of mouse oocytes was regulated by the estrogen-signaling pathway mediated by GPR30; FSH treatment markedly increased the mRNA expression of HAS2, PTGS2, and GREM1 in COCs. Exploration of the underlying mechanism suggested that E2 produced by mouse COCs regulated the phosphorylation level of extracellular signal-regulated kinase 1/2 (ERK1/2) through GPR30 and thereby promoted mouse cumulus-cell expansion and oocyte maturation. In conclusion, our study reveals that FSH induced estrogen production in mouse COCs through aromatase, and that aromatase/GPR30/ERK1/2 signaling is involved in FSH-induced cumulus expansion.//////////////////
Stimulation of ovarian cell proliferation by tetrabromobisphenol A but not tetrachlorobisphenol A through G protein-coupled receptor 30. Hoffmann M et al. (2017) Tetrabromobisphenol A (TBBPA) and tetrachlorobisphenol A (TCBPA) are bisphenol A (BPA) analogs, where the phenolic moieties are substituted with halogens (Br or Cl). Previous studies indicate that BPA has significant proliferative effects on in vitro cultured epithelial ovarian cancer (EOC) cells. Considering this, we analyzed the effects of both TBBPA and TCBPA at 1, 10, and 50nM on ovarian cancer cell proliferation. The majority of malignant ovarian tumors are epithelial in origin, but approximately 10% are classified as ovarian sex cord tumors, with the most common type being granulosa cell tumors (GCTs). OVCAR-3 and KGN cells were used as in vitro models to represent EOCs and GCTs, respectively. Here, we found that TBBPA, but not TCBPA, stimulated OVCAR-3 and KGN cell proliferation, with lower potency than BPA. The stimulatory effects of TBBPA and BPA on cell proliferation were reversed by pre-treatment with a G protein-coupled receptor 30 (GPR30) antagonist in both cell lines, which possess similar basal GPR30 expression levels. Taken together, our results show for the first time that TBBPA, which has lower potency than BPA, stimulates ovarian cancer cell proliferation through the GPR30 pathway.//////////////////
Expression of G protein estrogen receptor (GPER) on membrane of mouse oocytes during maturation. Li YR et al. PURPOSE: To determine expression of G-protein estrogen receptor (GPER) in mouse oocyte membrane during maturation. METHODS: The expression of GPER from different maturation stages of oocytes, in vivo and in vitro matured oocytes as well as aging oocytes was examined by immune-fluorescence GPR30 antibody and the images were analyzed by laser scanning confocal microscope. Further confirmation was performed by Western blots for cell fractionation. RESULTS: Significant fluorescent signal was observed on the surface of mouse oocytes. The image expression was lower in germinal vesicle (GV) stage than mature metaphase-II (M-II) stage oocytes. There was high expression in in-vivo matured oocytes compared to in vitro matured oocytes. The highest expression was observed in aging oocytes compared with other oocytes. CONCLUSIONS: The changes of expression of GPER on mouse oocytes plasma membrane confirm oocyte membrane maturation, suggesting that those changes of GPER may be related to the functional role of oocyte maturation.
Role of G protein-coupled estrogen receptor 1, GPER, in inhibition of oocyte maturation by endogenous estrogens in zebrafish. Pang Y et al. Estrogen inhibition of oocyte maturation (OM) and the role of GPER (formerly known as GPR30) were investigated in zebrafish. Estradiol-17beta (E2) and G-1, a GPER-selective agonist, bound to zebrafish oocyte membranes suggesting the presence of GPER which was confirmed by immunocytochemistry using a specific GPER antibody. Incubation of follicle-enclosed oocytes with an aromatase inhibitor, ATD, and enzymatic and manual removal of the ovarian follicle cell layers significantly increased spontaneous OM which was partially reversed by co-treatment with either 100 nM E2 or G-1. Incubation of denuded oocytes with the GPER antibody blocked the inhibitory effects of estrogens on OM, whereas microinjection of estrogen receptor alpha (ERalpha) antisense oligonucleotides into the oocytes was ineffective. The results suggest that endogenous estrogens produced by the follicle cells inhibit or delay spontaneous maturation of zebrafish oocytes and that this estrogen action is mediated through GPER. Treatment with E2 and G-1 also attenuated the stimulatory effect of the teleost maturation-inducing steroid, 17,20beta-dihyroxy-4-pregnen-3-one (DHP), on OM. Moreover, E2 and G-1 down-regulated the expression of membrane progestin receptor alpha (mPRalpha), the intermediary in DHP induction of OM. Conversely DHP treatment caused a> 50% decline in GPER mRNA levels. The results suggest that estrogens and GPER are critical components of the endocrine system controlling the onset of OM in zebrafish. A model is proposed for the dual control of the onset of oocyte maturation in teleosts by estrogens and progestins acting through GPER and mPRalpha, respectively, at different stages of oocyte development.
GPR30 expression is required for estrogen stimulation of primordial follicle formation in the hamster ovary. Wang C et al. Estradiol-17beta (E2) plays an important role in the formation and development of primordial follicles, but the mechanisms remain unclear. G protein-coupled receptor 30 (GPR30) can mediate a rapid and transcription-independent E2 signaling in various cells. The objectives of this study were to examine whether GPR30 was expressed in the neonatal hamster ovary, and whether it could mediate estrogen action during the formation of primordial follicles. GPR30 mRNA levels decreased from the 13(th) day of gestation (E13) through the 2(nd) day of postnatal (P2) life, followed by steady increases from P3 through P6. Consistent with the changes in mRNA levels, GPR30 protein expression decreased from E13 to P2 followed by a significant increase by P7, the day before the first appearance of primordial follicles in the hamster ovary. GPR30 was expressed both in the oocytes and somatic cells, although the expression in the oocytes was low. GPR30 protein was located primarily in the perinuclear endoplasmic reticulum, which was also the site of E2-BSA (E2-BSA-FITC) binding. E2 or E2-BSA increased intracellular calcium in neonatal hamster ovary cells in vitro. Exposure to GPR30 siRNA in vitro significantly reduced GPR30 mRNA and protein levels in cultured hamster ovaries, attenuated E-BSA binding to cultured P6 ovarian cells, and markedly suppressed E-stimulated primordial follicle formation. These results suggest that a membrane estrogen receptor, GPR30, is expressed in the ovary during perinatal development and mediates E2 action on primordial follicle formation.
Expression regulated by
FSH, LH
Comment
Induction of G protein-coupled estrogen receptor (GPER) and nuclear steroid hormone receptors by gonadotropins in human granulosa cells. Pavlik R et al. Estradiol and progesterone mediate their actions by binding to classical nuclear receptors, estrogen receptor a (ERa) and estrogen receptor ?(ER? and progesterone receptor A and B (PR-A and PR-B) and the non-classical G protein-coupled estrogen receptor (GPER). Several animal knock-out models have shown the importance of the receptors for growth of the oocyte and ovulation. The aim of our study was to identify GPER in human granulosa cells (GC) for the first time. Moreover, the effect of different doses of gonadotropins on estrogen and progesterone receptors in the human ovary should be investigated as follicle stimulating hormone (FSH) and luteinizing hormone (LH) are also responsible for numerous mechanisms in the ovary like induction of the steroid biosynthesis. Human GC were cultured in vitro and stimulated with different doses of recombinant human FSH or LH. Receptor expression was analyzed by immunocytochemistry and quantitative real-time RT-PCR. GPER could be identified for the first time in human GC. It could be shown that high concentrations of LH increase GPER protein expression. Furthermore FSH and LH increased ER? PR-A and PR-B significantly on protein level. These findings were verified for high doses of FSH and LH on mRNA level. ERa was not affected with FSH or LH. We assume that gonadotropins induce GPER, ER?and PR in luteinized granulosa cells.
The Inhibitory Control of Oocyte Maturation in the Zebrafish: The Role of the G Protein-Coupled Estrogen Receptor and Epidermal Growth Factor. Van Der Kraak G et al. The work of Peyton and Thomas in this issue contributes valuable insight into the complex interactions of Gper and Egf in maintaining of the meiotic arrest in zebrafish ovarian follicles. 'Involvement of Epidermal Growth Factor Receptor Signaling in Estrogen Inhibition of Oocyte Maturation Mediated Through the G Protein-Coupled Estrogen Receptor (Gper) in Zebrafish (Danio rerio)' by Candace Peyton and Peter Thomas. Biol Reprod 2011; published ahead of print February 23, 2011, doi:10.1095/biolreprod.110.088765.
Ovarian localization
Oocyte, Cumulus, Granulosa, Theca, Luteal cells
Comment
Expression pattern of G protein‑coupled estrogen receptor 1 (GPER) in human cumulus granulosa cells (CGCs) of patients with PCOS. Zang L et al. (2016) Estradiol mediates its actions by binding to classical nuclear receptors, estrogen receptor α (ER-α) and estrogen receptor β (ER-β), and the non-classical G protein-coupled estrogen receptor 1(GPER). Several gene knockdown models have shown the importance of the receptors for growth of the oocyte and for ovulation. The aim of our study was to identify the pattern of GPER expression in human cumulus granulosa cells (CGCs) from ovarian follicles at different stages of oocyte maturation, and the differences of GPER expression between polycystic ovary syndrome (PCOS) patients and non-PCOS women. Thirty-eight cases of PCOS patients and a control group of thirty-two infertile women without PCOS were used in this study. GPER's location in CGCs was investigated by immunohistochemistry. Quantitative RT-PCR and western blot were used to identify the quantify GPER expression. Here we demonstrated that GPER was expressed in CGCs of both PCOS patients and non-PCOS women, and the expression of GPER was decreased significantly during oocyte maturation. But the expression levels of GPER in CGCs of PCOS patients and non-PCOS women were not significantly different. The data indicate that GPER may play a role during human oocyte maturation through its action in cumulus granulosa cells. AMHRIIs: anti-Mullerian hormone type II receptors; BMI: body mass index; CGCs: cumulus granulosa cells; COH: controlled ovarian hyperstimulation; E2: estradiol; EGFR: epidermal growth factor receptor; ER-α: estrogen receptor; ER-β: estrogen receptor β; FF: follicular fluid; FSH: follicle-stimulating hormone; GCs: granulosa cells; GPER: G protein-coupled estrogen receptor 1; GV: germinal vesicle; GVBD: germinal vesicle breakdown; HCG: human chorionic gonadotropin; IRS: immunoreactive score; IVF-ET: in vitro fertilization and embryo transfer; MI: metaphase I; MII: metaphase II; MAPK: mitogen-activated protein kinase; OCCCs: oocyte corona cumulus complexes; PCOS: polycystic ovarian syndrome; qRT-PCR: quantitative real-time PCR: qRT-PCR.//////////////////Expression pattern of G protein‑coupled estrogen receptor 1 (GPER) in human cumulus granulosa cells (CGCs) of patients with PCOS. Zang L et al. (2017) Estradiol mediates its actions by binding to classical nuclear receptors, estrogen receptor α (ER-α) and estrogen receptor β (ER-β), and the non-classical G protein-coupled estrogen receptor 1(GPER). Several gene knockdown models have shown the importance of the receptors for growth of the oocyte and for ovulation. The aim of our study was to identify the pattern of GPER expression in human cumulus granulosa cells (CGCs) from ovarian follicles at different stages of oocyte maturation, and the differences of GPER expression between polycystic ovary syndrome (PCOS) patients and non-PCOS women. Thirty-eight cases of PCOS patients and a control group of thirty-two infertile women without PCOS were used in this study. GPER's location in CGCs was investigated by immunohistochemistry. Quantitative RT-PCR and western blot were used to identify the quantify GPER expression. Here we demonstrated that GPER was expressed in CGCs of both PCOS patients and non-PCOS women, and the expression of GPER was decreased significantly during oocyte maturation. But the expression levels of GPER in CGCs of PCOS patients and non-PCOS women were not significantly different. The data indicate that GPER may play a role during human oocyte maturation through its action in cumulus granulosa cells. AMHRIIs: anti-Mullerian hormone type II receptors; BMI: body mass index; CGCs: cumulus granulosa cells; COH: controlled ovarian hyperstimulation; E2: estradiol; EGFR: epidermal growth factor receptor; ER-α: estrogen receptor; ER-β: estrogen receptor β; FF: follicular fluid; FSH: follicle-stimulating hormone; GCs: granulosa cells; GPER: G protein-coupled estrogen receptor 1; GV: germinal vesicle; GVBD: germinal vesicle breakdown; HCG: human chorionic gonadotropin; IRS: immunoreactive score; IVF-ET: in vitro fertilization and embryo transfer; MI: metaphase I; MII: metaphase II; MAPK: mitogen-activated protein kinase; OCCCs: oocyte corona cumulus complexes; PCOS: polycystic ovarian syndrome; q quantitative real-time PCR: qRT-PCR.//////////////////
Expression of GPR30 in the hamster ovary: differential regulation by gonadotropins and steroid hormones. Wang C et al. The non-genomic actions of estradiol-17beta (E2) are mediated by transmembrane estrogen receptors (mERs). Recently, G-protein coupled-receptor 30 (GPR30) has been suggested to be a mER that can mediate rapid and transcription-independent E2 signaling in different cell types. However, the expression, regulation or biological relevance of GPR30 in the ovary remains unknown. We examined the expression and hormonal regulation of GPR30 mRNA and protein in hamster ovarian cells during the estrous cycle, and following hypophysectomy and hormone replacement. GPR30 protein expression was high in the theca, appreciable in the granulosa, but low in luteal cells. GPR30 protein levels in granulosa and theca cells increased steadily with the development of preantral and antral follicles, respectively. GPR30 mRNA and protein levels increased significantly on diestrous (day 3 of the estrous cycle), but decreased at day 4:1600h following the LH surge. GPR30 mRNA levels increased significantly following hypophysectomy (HX). Whereas steroid treatment failed to alter ovarian GPR30 mRNA levels, either FSH or LH effectively reduced the levels. Interestingly, the decreased in GPR30 mRNA corresponded to a marked increase in the receptor protein levels. FSH treatment, either alone or together with LH, resulted in a marked increase in GPR30 immunostaining in granulosa cells. LH alone significantly increased immunostaining in theca cells. These results suggest that GPR30 is expressed in the membrane of hamster granulosa and theca cells, and the expression is regulated by gonadotropins. The unique pattern of GPR30 expression suggests that gonadotropin regulated follicular cell functions may involve GPR30 activity.
The G-Protein Coupled Estrogen Receptor (GPER) is Expressed in Normal Human Ovaries and is Upregulated in Ovarian Endometriosis and Pelvic Inflammatory Disease Involving the Ovary. Heublein S et al. Estrogens play a crucial role in maintaining ovarian function. Deregulation of estrogen signals is associated with fertility-impairing disorders. The aim of this study was to investigate whether the G-protein-coupled estrogen receptor (GPER) is present in the human ovary. Additionally, we analyzed the folliculogenesis and ovarian endometriosis in GPER expression. Seventy-nine patients (ovarian endometriosis, n = 26; ovarian pelvic inflammatory disease [PID], n = 10; normal ovaries/endometrium, n = 30/13) were analyzed by immunohistochemistry. Normal ovaries were also assessed by real-time polymerase chain reaction and double immunofluorescence. The most intense expression of GPER was noted in the ovarian surface epithelium. Theca cells and oocytes were also significantly positive. Expression of GPER was more frequent in mature follicles/oocytes than in primordial ones, implying that GPER could be a selector during folliculogenesis. Moreover, GPER was upregulated in ovarian endometriosis and PID. Overexpression of GPER in both inflammation and endometriosis affecting the ovary may prove useful in explaining/predicting the main endometriosis-related symptoms.
Follicle stages
Secondary, Antral, Preovulatory, Corpus luteum
Comment
Mitogen-activated protein kinase 8 (MAP3K8) mediates the signaling pathway of estradiol stimulating progesterone production through G protein-coupled receptor 30 (GPR30) in mouse Corpus luteum. Liu Y et al. (2015) The corpus luteum (CL) is a transient endocrine gland developed from the ovulated follicles, and the most important function is to synthesize and secrete progesterone (P4), a key hormone to maintain normal pregnancy and estrus cycle in most mammals. It is known that estrogen has a vital role in stimulating P4 synthesis in CL, but it still remains unclear about the mechanism of estrodiol (E2) regulating P4 production in CL. Our results here firstly show that all of the CL cells express Mitogen-activated Protein Kinase 8 (MAP3K8) and MAP3K8 level is much higher at mid-stage than at early and late stages during CL development. The further functional studies show that the forced inhibition of endogenous MAP3K8 by using MAP3K8-siRNA and MAP3K8 signaling inhibitor (MAP3K8i) in the luteal cells significantly block the P4 synthesis and neutralize the enhancing effect of E2 on P4 production in the CL. In addition, our results here demonstrate that the stimulating effect of E2 on P4 synthesis relies on the estrogen no-classical protein-coupled receptor 30 (GPR30) and MAP3K8 is involved in mediating the GPR30 signaling of E2 affecting P4 synthesis via stimulating ERK phosphorylation. These novel findings are critical for our understanding the ovary physiology and pathological mechanism.//////////////////