Activation of GPER-1 estradiol receptor downregulates production of testosterone in isolated rat Leydig cells and adult human testis.

PURPOSE: Estradiol (E2) modulates testicular functions including steroidogenesis, but the mechanisms of E2 signaling in human testis are poorly understood. GPER-1 (GPR30), a G protein-coupled membrane receptor, mediates rapid genomic and non-genomic response to estrogens. The aim of this study was to evaluate GPER-1 expression in the testis, and its role in estradiol dependent regulation of steroidogenesis in isolated rat Leydig cells and human testis. MATERIALS AND METHODS: Isolated Leydig cells (LC) from adult rats and human testicular tissue were used in this study. Expression and localization studies of GPER-1 were performed with qRT-PCR, immunofluorescence, immunohistochemistry and Western Blot. Luteinizing Hormone (LH) -stimulated, isolated LC were incubated with estradiol, G-1 (GPER-1-selective agonist), and estrogen receptor antagonist ICI 182,780. Testosterone production was measured with radioimmunoassay. LC viability after incubation with G-1 was measured using 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt (MTS) assay. RESULTS: GPER-1 mRNA is abundantly expressed in rat LC and human testis. Co-localization experiments showed high expression levels of GPER-1 protein in LC. E2-dependent activation of GPER-1 lowers testosterone production in isolated rats LCs and in human testis, with statistically and clinically significant drops in testosterone production by 20-30% as compared to estradiol-naïve LC. The exposure to G-1 does not affect viability of isolated LCs. CONCLUSIONS: Our results indicate that activation of GPER-1 lowers testosterone levels in the rat and human testis. The expression of GPER-1 in human testis, which lack ERα, makes it an exciting target for developing new agents affecting testosterone production in men

Nuclear Progestin Receptor (Pgr) Knockouts in Zebrafish Demonstrate Role for Pgr in Ovulation but Not in Rapid Non-Genomic Steroid Mediated Meiosis Resumption

Progestins, progesterone derivatives, are the most critical signaling steroid for initiating final oocyte maturation (FOM) and ovulation, in order to advance fully-grown immature oocytes to become fertilizable eggs in basal vertebrates. It is well-established that progestin induces FOM at least partly through a membrane receptor and a non-genomic steroid signaling process, which precedes progestin triggered ovulation that is mediated through a nuclear progestin receptor (Pgr) and genomic signaling pathway. To determine whether Pgr plays a role in a non-genomic signaling mechanism during FOM, we knocked out Pgr in zebrafish using transcription activator-like effector nucleases (TALENs) and studied the oocyte maturation phenotypes of Pgr knockouts (Pgr-KOs). Three TALENs-induced mutant lines with different frame shift mutations were generated. Homozygous Pgr-KO female fish were all infertile while no fertility effects were evident in homozygous Pgr-KO males. Oocytes developed and underwent FOM normally in vivo in homozygous Pgr-KO female compared to the wild-type controls, but these mature oocytes were trapped within the follicular cells and failed to ovulate from the ovaries. These oocytes also underwent normal germinal vesicle breakdown (GVBD) and FOM in vitro, but failed to ovulate even after treatment with human chronic gonadotropin (HCG) or progestin (17α,20β-dihydroxyprogesterone or DHP), which typically induce FOM and ovulation in wild-type oocytes. The results indicate that anovulation and infertility in homozygous Pgr-KO female fish was, at least in part, due to a lack of functional Pgr-mediated genomic progestin signaling in the follicular cells adjacent to the oocytes. Our study of Pgr-KO supports previous results that demonstrate a role for Pgr in steroid-dependent genomic signaling pathways leading to ovulation, and the first convincing evidence that Pgr is not essential for initiating non-genomic progestin signaling and triggering of meiosis resumption

Low expression of G protein-coupled oestrogen receptor 1 (GPER) is associated with adverse survival of breast cancer patients

G protein-coupled oestrogen receptor 1 (GPER), also called G protein-coupled receptor 30 (GPR30), is attracting considerable attention for its potential role in breast cancer development and progression. Activation by oestrogen (17β-oestradiol; E2) initiates short term, non-genomic, signalling events both in vitro and in vivo. Published literature on the prognostic value of GPER protein expression in breast cancer indicates that further assessment is warranted. We show, using immunohistochemistry on a large cohort of primary invasive breast cancer patients (n=1245), that low protein expression of GPER is not only significantly associated with clinicopathological and molecular features of aggressive behaviour but also significantly associated with adverse survival of breast cancer patients. Furthermore, assessment of GPER mRNA levels in the METABRIC cohort (n=1980) demonstrates that low GPER mRNA expression is significantly associated with adverse survival of breast cancer patients. Using artificial neural networks, genes associated with GPER mRNA expression were identified; these included notch-4 and jagged-1. These results support the prognostic value for determination of GPER expression in breast cancer

Emerging roles for the novel estrogen-sensing receptor GPER1 in the CNS

Estrogens play a key role in regulating reproductive and neuroendocrine function by activating classical nuclear steroid receptors that act as ligand gated transcription factors. However evidence is growing that estrogens also promote rapid non-genomic responses via activation of membrane-associated estrogen receptors. The G protein-coupled estrogen receptor (GPER1; also known as GPR30) has been identified as one of the main estrogen-sensitive receptors responsible for the rapid non-genomic actions of estrogen. In recent years, our understanding of the CNS actions of GPER1s has significantly increased following the development of selective pharmacological tools and via the use of transgenic technologies to knockout GPER1 in mice. Here we review recent advances that have been made to uncover the role of GPER1s in the CNS.</p

Metabolic programming of a beige adipocyte phenotype by genistein

Scope Promoting the development of brown or beige adipose tissue may protect against obesity and related metabolic features, and potentially underlies protective effects of genistein in mice. Methods and results We observed that application of genistein to 3T3-L1 adipocytes changed the lipid distribution from large droplets to a multilocular distribution, reduced mRNAs indicative of white adipocytes (ACC, Fasn, Fabp4, HSL, chemerin, and resistin) and increased mRNAs that are a characteristic feature of brown/beige adipocytes (CD-137 and UCP1). Transcripts with a role in adipocyte differentiation (Cebpβ, Pgc1α, Sirt1) peaked at different times after application of genistein. These responses were not affected by the estrogen receptor (ER) antagonist fulvestrant, revealing that this action of genistein is not through the classical ER pathway. The Sirt1 inhibitor Ex-527 curtailed the genistein-mediated increase in UCP1 and Cebpβ mRNA, revealing a role for Sirt1 in mediating the effect. Baseline oxygen consumption and the proportional contribution of proton leak to maximal respiratory capacity was greater for cells exposed to genistein, demonstrating greater mitochondrial uncoupling. Conclusions We conclude that genistein acts directly on adipocytes or on adipocyte progenitor cells to programme the cells metabolically to adopt features of beige adipocytes. Thus, this natural dietary agent may protect against obesity and related metabolic disease

G protein-coupled estrogen receptor in GtoPdb v.2023.1

The G protein-coupled estrogen receptor (GPER, nomenclature as agreed by the NC-IUPHAR Subcommittee on the G protein-coupled estrogen receptor [26]) was identified following observations of estrogen-evoked cyclic AMP signalling in breast cancer cells [2], which mirrored the differential expression of an orphan 7-transmembrane receptor GPR30 [6]. There are observations of both cell-surface and intracellular expression of the GPER receptor [29, 34]. Selective agonist/ antagonists for GPER have been characterized [26]. Antagonists of the nuclear estrogen receptor, such as fulvestrant [11], tamoxifen [29, 34] and raloxifene [25], as well as the flavonoid 'phytoestrogens' genistein and quercetin [18], are agonists of GPER. Reviews of GPER pharmacology have been published [26]. The roles of GPER in (patho)physiological systems throughout the body (cardiovascular, metabolic, endocrine, immune, reproductive) and in cancer have also been reviewed [26, 27, 20, 17, 9]. The GPER-selective agonist G-1 is currently in Phase I/II clinical trials for cancer (NCT04130516)

G protein-coupled estrogen receptor (version 2019.4) in the IUPHAR/BPS Guide to Pharmacology Database

The G protein-coupled estrogen receptor (GPER, nomenclature as agreed by the NC-IUPHAR Subcommittee on the G protein-coupled estrogen receptor [24]) was identified following observations of estrogen-evoked cyclic AMP signalling in breast cancer cells [2], which mirrored the differential expression of an orphan 7-transmembrane receptor GPR30 [5]. There are observations of both cell-surface and intracellular expression of the GPER receptor [27, 32]. Selective agonist/ antagonists for GPER have been characterized [24]. Antagonists of the nuclear estrogen receptor, such as fulvestrant [10], tamoxifen [27, 32] and raloxifene [23], as well as the flavonoid 'phytoestrogens' genistein and quercetin [16], are agonists of GPER. A complete review of GPER pharmacology has been recently published [24]. The roles of GPER in physiological systems throughout the body (cardiovascular, metabolic, endocrine, immune, reproductive) and in cancer have also been reviewed [24, 25, 18, 15, 8]

G protein-coupled estrogen receptor in GtoPdb v.2021.3

The G protein-coupled estrogen receptor (GPER, nomenclature as agreed by the NC-IUPHAR Subcommittee on the G protein-coupled estrogen receptor [25]) was identified following observations of estrogen-evoked cyclic AMP signalling in breast cancer cells [2], which mirrored the differential expression of an orphan 7-transmembrane receptor GPR30 [6]. There are observations of both cell-surface and intracellular expression of the GPER receptor [28, 33]. Selective agonist/ antagonists for GPER have been characterized [25]. Antagonists of the nuclear estrogen receptor, such as fulvestrant [11], tamoxifen [28, 33] and raloxifene [24], as well as the flavonoid \u27phytoestrogens\u27 genistein and quercetin [17], are agonists of GPER. A complete review of GPER pharmacology has been published [25]. The roles of GPER in physiological systems throughout the body (cardiovascular, metabolic, endocrine, immune, reproductive) and in cancer have also been reviewed [25, 26, 19, 16, 9]. The GPER-selective agonist G-1 is currently in Phase I/II clinical trials for cancer (NCT04130516)