GPR30 Research Articles

GPR30 agonist G1 combined with hypothermia alleviates cognitive impairment and anxiety-like behavior after subarachnoid hemorrhage in rats.

This study aimed to investigate the treatment effect of G protein-coupled receptor 30 (GPR30) agonist G1 combined with hypothermia (HT) on cognitive impairment and anxiety-like behavior after subarachnoid hemorrhage (SAH) in rats. Fifty male rats were randomly assigned to one of five groups: Sham group, SAH group, SAH+G1 group, SAH+HT group, and SAH+G1+HT group. The SAH rat model was established by modified endovascular puncture in all groups except the Sham group. Neurological function after the operation was assessed by Garcia scoring. The degree of rat cerebral edema was determined using dry-wet weighing method on the 28th day after operation. Moreover, the behavioral test was performed on rats on the 4th and 28th days after operation. Compared with Sham group, the Garcia score of each SAH rat model group decreased significantly on the first day and thereafter increased gradually. However, the recovery rate of each treatment group was higher than the SAH group (no treatment), and the Garcia score of SAH+G1+HT group was much higher than the SAH group on the seventh day after operation. In addition, each treatment group could obviously reduce the cerebral edema degree of SAH rats, among which rats in SAH+G1+HT group had lower cerebral edema degree than SAH+G1 group and SAH+HT group. Behavioral test results showed that the combination of GPR30 agonist G1 and HT markedly improved the learning and memory ability of SAH rats, alleviated their anxiety- and emotion-related behavior, and enhanced their social interaction. GPR30 agonist G1 combined with HT reduces cognitive impairment and anxiety-like behavior in rats with SAH.

Lysophosphatidylglucoside/GPR55 signaling promotes foam cell formation in human M2c macrophages

Atherosclerosis is a major cause of cerebral and cardiovascular diseases. Intravascular plaques, a well-known pathological finding of atherosclerosis, have a necrotic core composed of macrophages and dead cells. Intraplaque macrophages, which are classified into various subtypes, play key roles in maintenance of normal cellular microenvironment. Excessive uptake of oxidized low-density lipoprotein causes conversion of macrophages to foam cells, and consequent progression/exacerbation of atherosclerosis. G-protein-coupled receptor 55 (GPR55) signaling has been reported to associate with atherosclerosis progression. We demonstrated recently that lysophosphatidylglucoside (lysoPtdGlc) is a specific ligand of GPR55, although in general physiological ligands of GPR55 are poorly understood. Phosphatidylglucoside is expressed on human monocytes and can be converted to lysoPtdGlc. In the present study, we examined possible involvement of lysoPtdGlc/GPR55 signaling in foam cell formation. In monocyte-derived M2c macrophages, lysoPtdGlc/GPR55 signaling inhibited translocation of ATP binding cassette subfamily A member 1 to plasma membrane, and cholesterol efflux. Such inhibitory effect was reversed by GPR55 antagonist ML193. LysoPtdGlc/GPR55 signaling in M2c macrophages was involved in excessive lipid accumulation, thereby promoting foam cell formation. Our findings suggest that lysoPtdGlc/GPR55 signaling is a potential therapeutic target for inhibition of atherosclerosis progression.

G Protein-Coupled Receptor 40 Agonist LY2922470 Alleviates Ischemic-Stroke-Induced Acute Brain Injury and Functional Alterations in Mice.

Stroke is a major cause of fatalities and disabilities around the world, yet the available treatments for it are still limited. The quest for more efficacious drugs and therapies is still an arduous task. LY2922470 is currently used as a G protein-coupled receptor 40 (GPR40) agonist for the treatment of type 2 diabetes. Previous studies have reported protective effects of other GPR40 activators on the brain; however, it remains unclear whether LY2922470 could be a new stroke therapy and improve the stroke-induced brain damage. Here, we first reveal that the transcriptomic gene signature induced by LY2922470 is highly similar to those induced by some agents being involved in defending from cerebrovascular accidents and transient ischemic attacks, including acetylsalicylic acid, progesterone, estradiol, dipyridamole, and dihydroergotamine. This result thus suggests that LY2922470 could have protective effects against ischemic stroke. As a result, further experiments show that giving the small molecule LY2922470 via oral administration or intraperitoneal injection was seen to have a positive effect on neuroprotection with a reduction in infarct size and an improvement in motor skills in mice. Finally, it was demonstrated that LY2922470 could successfully mitigate the harm to the brain caused by ischemic stroke.

Lysophosphatidylserine induces necrosis in pressure overloaded male mouse hearts via G protein coupled receptor 34

Heart failure is a leading cause of mortality in developed countries. Cell death is a key player in the development of heart failure. Calcium-independent phospholipase A2β (iPLA2β) produces lipid mediators by catalyzing lipids and induces nuclear shrinkage in caspase-independent cell death. Here, we show that lysophosphatidylserine generated by iPLA2β induces necrotic cardiomyocyte death, as well as contractile dysfunction mediated through its receptor, G protein-coupled receptor 34 (GPR34). Cardiomyocyte-specific iPLA2β-deficient male mice were subjected to pressure overload. While control mice showed left ventricular systolic dysfunction with necrotic cardiomyocyte death, iPLA2β-deficient mice preserved cardiac function. Lipidomic analysis revealed a reduction of 18:0 lysophosphatidylserine in iPLA2β-deficient hearts. Knockdown of Gpr34 attenuated 18:0 lysophosphatidylserine-induced necrosis in neonatal male rat cardiomyocytes, while the ablation of Gpr34 in male mice reduced the development of pressure overload-induced cardiac remodeling. Thus, the iPLA2β—lysophosphatidylserine—GPR34—necrosis signaling axis plays a detrimental role in the heart in response to pressure overload.

Insight into the Potential Mechanisms of Endocrine Disruption by Dietary Phytoestrogens in the Context of the Etiopathogenesis of Endometriosis.

Phytoestrogens (PEs) are estrogen-like nonsteroidal compounds derived from plants (e.g., nuts, seeds, fruits, and vegetables) and fungi that are structurally similar to 17β-estradiol. PEs bind to all types of estrogen receptors, including ERα and ERβ receptors, nuclear receptors, and a membrane-bound estrogen receptor known as the G protein-coupled estrogen receptor (GPER). As endocrine-disrupting chemicals (EDCs) with pro- or antiestrogenic properties, PEs can potentially disrupt the hormonal regulation of homeostasis, resulting in developmental and reproductive abnormalities. However, a lack of PEs in the diet does not result in the development of deficiency symptoms. To properly assess the benefits and risks associated with the use of a PE-rich diet, it is necessary to distinguish between endocrine disruption (endocrine-mediated adverse effects) and nonspecific effects on the endocrine system. Endometriosis is an estrogen-dependent disease of unknown etiopathogenesis, in which tissue similar to the lining of the uterus (the endometrium) grows outside of the uterus with subsequent complications being manifested as a result of local inflammatory reactions. Endometriosis affects 10-15% of women of reproductive age and is associated with chronic pelvic pain, dysmenorrhea, dyspareunia, and infertility. In this review, the endocrine-disruptive actions of PEs are reviewed in the context of endometriosis to determine whether a PE-rich diet has a positive or negative effect on the risk and course of endometriosis.

Activation of G-protein-coupled receptor 39 reduces neuropathic pain in a rat model.

Activated G-protein-coupled receptor 39 (GPR39) has been shown to attenuate inflammation by interacting with sirtuin 1 (SIRT1) and peroxisome proliferator-activated receptor-γ coactivator 1α (PGC-1α). However, whether GPR39 attenuates neuropathic pain remains unclear. In this study, we established a Sprague-Dawley rat model of spared nerve injury-induced neuropathic pain and found that GPR39 expression was significantly decreased in neurons and microglia in the spinal dorsal horn compared with sham-operated rats. Intrathecal injection of TC-G 1008, a specific agonist of GPR39, significantly alleviated mechanical allodynia in the rats with spared nerve injury, improved spinal cord mitochondrial biogenesis, and alleviated neuroinflammation. These changes were abolished by GPR39 small interfering RNA (siRNA), Ex-527 (SIRT1 inhibitor), and PGC-1α siRNA. Taken together, these findings show that GPR39 activation ameliorates mechanical allodynia by activating the SIRT1/PGC-1α pathway in rats with spared nerve injury.

Neuroprotective Potential of Raloxifene via G-Protein-Coupled Estrogen Receptors in Aβ-Oligomer-Induced Neuronal Injury.

Amyloid-β (Aβ) is one of the causes of Alzheimer's disease (AD), damaging nerve membranes and inducing neurotoxicity. AD is more prevalent in female patients than in male patients, and women are more susceptible to developing AD due to the decline in estrogen levels around menopause. Raloxifene, a selective estrogen receptor modulator, exhibits protective effects by activating the transmembrane G-protein-coupled estrogen receptor (GPER). Additionally, raloxifene prevents mild cognitive impairment and restores cognition. However, the influence of raloxifene via GPER on highly toxic Aβ-oligomers (Aβo)-induced neurotoxicity remains uncertain. In this study, we investigated the GPER-mediated neuroprotective effects of raloxifene against the neurotoxicity caused by Aβo-induced cytotoxicity. The impact of raloxifene on Aβo-induced cell damage was evaluated using measures such as cell viability, production of reactive oxygen species (ROS) and mitochondrial ROS, peroxidation of cell-membrane phospholipids, and changes in intracellular calcium ion concentration ([Ca2+]i) levels. Raloxifene hindered Aβo-induced oxidative stress and reduced excessive [Ca2+]i, resulting in improved cell viability. Furthermore, these effects of raloxifene were inhibited with pretreatment with a GPER antagonist. Our findings suggest that raloxifene safeguards against Aβo-induced neurotoxicity by modifying oxidative parameters and maintaining [Ca2+]i homeostasis. Raloxifene may prove effective in preventing and inhibiting the progression of AD.

Activation of G protein-coupled estrogen receptor stimulates placental human chorionic gonadotropin expression through PKA-CREB signaling

The placenta-secreted human chorionic gonadotropin (hCG) is a hormone that plays a critical role in inducing ovarian progesterone production, which is required for maintaining normal pregnancy. The bioavailability of hCG depends on the expression of the beta-subunit of hCG (hCG-β) which is encoded by the chorionic gonadotropin beta (CGB) gene. G protein-coupled estrogen receptor (GPER) is a membrane estrogen receptor involved in non-genomic estrogen signaling. Estradiol (E2) has been shown to stimulate hCG production. However, the role of the GPER in regulating CGB expression remains unknown. In the present study, our results revealed that treatment with G1 upregulated CGB expression in two human choriocarcinoma cell lines, BeWo and JEG-3, and primary human cytotrophoblast cells. In addition, G1 treatment activated the cAMP-response element binding protein (CREB). Using a pharmacological inhibitor and siRNA-mediated knockdown approach, we showed that the stimulatory effect of G1 on CGB expression is mediated by the protein kinase A (PKA)-CREB signaling pathway. This study increases the understanding of the role of GPER in the human placenta. In addition, our results provide important insights into the molecular mechanisms that mediate hCG expression, which may lead to the development of alternative therapeutic approaches for treating placental diseases.

Estradiol receptors inhibit long-term potentiation in the dorsomedial striatum.

Estradiol, a female sex hormone and the predominant form of estrogen, has diverse effects throughout the brain including in learning and memory. Estradiol modulates several types of learning that depend on the dorsomedial striatum (DMS), a subregion of the basal ganglia involved in goal-directed learning, cued action-selection, and motor skills. A cellular basis of learning is synaptic plasticity, and the presence of extranuclear estradiol receptors ERα, ERβ, and G protein-coupled estrogen receptor (GPER) throughout the DMS suggests that estradiol may influence rapid cellular actions including those involved in plasticity. To test whether estradiol affects synaptic plasticity in the DMS, corticostriatal long-term potentiation (LTP) was induced using theta-burst stimulation in ex vivo brain slices from intact male and female C57BL/6 mice. Extracellular field recordings showed that female mice in the diestrus stage of the estrous cycle exhibited LTP similar to male mice, while female mice in estrus did not exhibit LTP. Furthermore, antagonists of ERα or GPER rescued LTP in estrus females and agonists of ERα or GPER reduced LTP in diestrus females. In males, activating ERα but not GPER reduced LTP. These results uncover an inhibitory action of estradiol receptors on cellular learning in the DMS and suggest a cellular mechanism underlying the impairment in certain types of DMS-based learning observed in the presence of high estradiol. Due to the dorsal striatum's role in drug addiction, these findings may provide a mechanism underlying an estradiol-mediated progression from goal-directed to habitual drug use.Significance StatementThis study examined the role of the female reproductive cycle and female sex hormones in synaptic plasticity, a cellular process that underlies learning behavior, in a brain region involved in goal-directed learning. Synaptic plasticity was similar between male mice and female mice in the low estradiol phase of the cycle. In contrast, female mice in a high estradiol phase of the cycle did not exhibit synaptic plasticity. The effect of estradiol was mediated by two of the three estradiol receptors found in the brain. The results have implications for the role of the female reproductive cycle in the development of drug addiction, which involves a progression from goal-directed learning to habit-based learning as drug use switches from recreational to compulsive.

Corticosterone rapidly reduces glutamatergic but not GABAergic transmission in the infralimbic prefrontal cortex of male mice

Rapid non-genomic effects of corticosteroid hormones, affecting glutamatergic and GABAergic transmission, have been described for many limbic structures in the rodent brain. These rapid effects appear to be region specific. It is not always clear which (or even whether) corticosteroid receptor -the glucocorticoid receptor (GR) or mineralocorticoid receptor (MR)- initiate these rapid effects. In the hippocampus and amygdala membrane-associated MR, but also membrane-associated GR (in amygdala), are involved. Other studies indicate that the rapid modulation may be induced by transactivation of kinases, or other receptors, like the G-protein coupled estrogen receptor (GPER) which was recently found to bind the mineralocorticoid aldosterone. In the current study we explored, in young adult male C57Bl6 mice, possible rapid effects of corticosterone on layer 2/3 infralimbic-prefrontal cortex (IL-PFC) neurons. We show that corticosterone, via non-genomic MR activation, reduces the mEPSC -but does not affect mIPSC- frequency; we observed no effect on mEPSC or mIPSC amplitude. As a result, overall spontaneous activity in the IL-PFC is suppressed. A potential role of GPER cannot be excluded, since G-15, an antagonist of GPER, also prevented the rapid effects of corticosterone.

Association of air pollution and green space with all-cause general practitioner and emergency room visits: A cross-sectional study of young people and adults living in Belgium

BackgroundResiding in areas with lower levels of air pollution and higher green space is beneficial to physical and mental health. We investigated associations of PM2.5, tree cover and grass cover with in-hours and out-of-hours GP visits and ER visits, for young people and adults. We estimated potential cost savings of GP visits attributable to high PM2.5. MethodsWe linked individual-level health insurance claims data of 315,123 young people (10–24 years) and 885,988 adults (25–64 years) with census tract-level PM2.5, tree cover and grass cover. Deploying negative binomial generalized linear mixed models, we estimated associations between quartile exposures and the three outcome measures. ResultsFor in-hours and out-of-hours GP visits, among young people as well as adults, statistically significant pairwise differences between quartiles suggested increasing beneficial effects with lower PM2.5. The same outcomes were statistically significantly less frequent in quartiles with highest tree cover (>30.00%) compared to quartiles with lower tree cover, but otherwise pairwise differences were not statistically significant. These associations largely persisted in rural and urban areas. Among adults living in urban areas lower grass cover was associated with increased in-hours GP visits and ER visits. Assuming causality, reducing PM2.5 levels to the lowest quartile (4.91–7.49 μg/m³), among adults, 195,964 in-hours and 74,042 out-of-hours GP visits could be avoided annually. Among young people, 27,457 in-hours and 22,423 out-of-hours GP visits could be avoided annually. Nationally, this amounts to an annual potential cost saving of €43 million (€5.7 million in out-of-pocket payments and €37.2 million in compulsory health insurance). ConclusionHigher ambient PM2.5 and lower tree cover show associations with higher non-urgent and urgent medical care utilization. These findings confirm the importance of reducing air pollution and fostering green zones, and that such policies may contribute positively to economic growth.

Low-dose bisphenols exposure sex-specifically induces neurodevelopmental toxicity in juvenile rats and the antagonism of EGCG

Bisphenols (BPs) can negatively affect neurobehaviors in rats, whereas the mechanism remains unclear. Here, the mechanism of BPs-induced neurodevelopmental toxicity and its effective detoxification measures were investigated in vitro and in vivo. In in vitro experiments, primary hippocampal neurons from neonatal rats of different genders were treated with bisphenol A (BPA), bisphenol S (BPS) and bisphenol B (BPB) at 1 nM-100 μM, epigallocatechin gallate (EGCG) and G15, an antagonist of G protein-coupled estrogen receptor (GPER) for 7 d. Results indicated that BPs affected neuronal morphogenesis, impaired GABA synthesis and Glu/GABA homeostasis. Neuronal morphogenetic damage induced by low-doses BPA may be mediated by GPER. Neurotoxicity of BPS is weaker than BPA and BPB. In in vivo studies, exposure to BPA (0.5 μg/kg·bw/day) on PND 10–40 caused oxidative stress and inflammation in rat hippocampus, disrupted neuronal morphogenesis and neurotransmitter homeostasis, ultimately impaired spatial memory of rats. Males are more sensitive to BPA exposure than females. Both in vivo and in vitro studies indicated that EGCG, a phytoestrogen, can alleviate BPA-induced neurotoxicity. Taken together, low-doses BPA exposure sex-specifically disrupted neurodevelopment and further impaired learning and memory ability in rats, which may be mediated by GPER. Promisingly, EGCG effectively mitigated the BPA-induced neurodevelopmental toxicity.

The G protein-coupled estrogen receptor of the trigeminal ganglion regulates acute and chronic itch in mice.

Itch is an unpleasant sensation that severely impacts the patient's quality of life. Recent studies revealed that the G protein-coupled estrogen receptor (GPER) may play a crucial role in the regulation of pain and itch perception. However, the contribution of the GPER in primary sensory neurons to the regulation of itch perception remains elusive. This study aimed to investigate whether and how the GPER participates in the regulation of itch perception in the trigeminal ganglion (TG). Immunofluorescence staining results showed that GPER-positive (GPER+ ) neurons of the TG were activated in both acute and chronic itch. Behavioral data indicated that the chemogenetic activation of GPER+ neurons of the TG of Gper-Cre mice abrogated scratching behaviors evoked by acute and chronic itch. Conversely, the chemogenetic inhibition of GPER+ neurons resulted in increased itch responses. Furthermore, the GPER expression and function were both upregulated in the TG of the dry skin-induced chronic itch mouse model. Pharmacological inhibition of GPER (or Gper deficiency) markedly increased acute and chronic itch-related scratching behaviors in mouse. Calcium imaging assays further revealed that Gper deficiency in TG neurons led to a marked increase in the calcium responses evoked by agonists of the transient receptor potential ankyrin A1 (TRPA1) and transient receptor potential vanilloid V1 (TRPV1). Our findings demonstrated that the GPER of TG neurons is involved in the regulation of acute and chronic itch perception, by modulating the function of TRPA1 and TRPV1. This study provides new insights into peripheral itch sensory signal processing mechanisms and offers new targets for future clinical antipruritic therapy.

G protein-coupled estrogen receptor activation by bisphenol-A disrupts lipid metabolism and induces ferroptosis in the liver

As a metabolic disruptor, bisphenol A (BPA) has been widely reported to disrupt lipid balance. Moreover, BPA has gained significant attention due to its estrogenic activity. While both ferroptosis and the G-protein-coupled estrogen receptor (GPER) have been implicated in lipid metabolism, their link to BPA-induced lipid accumulation remains unclear. In this study, chickens were randomly assigned to three groups and housed them for 4 weeks: a control group (0 μg/L BPA), a low dose group (50 μg/L BPA) and a high dose group (5000 μg/L BPA) to investigate the underlying mechanism of BPA-induced hepatotoxicity. Our results showed that BPA exposure significantly increased the contents of TG, TC, and LDL-C while decreasing HDL-C levels. We also found that BPA treatment altered the levels of genes involved in fatty acid β-oxidation (ampkα, cpt-1, and ppaα), synthesis (acc, fas, scd-1, and srebp-1) and absorption (lpl and cd36). Moreover, the results showed that the BPA group had higher levels of IL-1β, IL-18 and TNF-α. These results indicated that BPA exposure disrupted lipid metabolism and induced inflammation in the liver. We also demonstrated that BPA caused hepatic ferroptosis by raising iron content and the expression of genes related to lipid peroxidation (lpcat3, acsl4 and alox15), while reducing the expression of antioxidant system-associated genes (gpx4, slc7a11 and slc3a2). Importantly, BPA remarkably activated GPER expression in the liver. Interestingly, inhibition of GPER remarkably ameliorated BPA-induced lipid metabolism disorder, inflammatory response, and ferroptosis, indicating the crucial role of GPER in BPA-induced liver abnormalities. These findings highlight the link between GPER and ferroptosis in BPA-induced hepatotoxicity, providing new insights into the potential hazard of BPA.

The peripheral endocannabinoid system and its association with biomarkers of inflammation in untreated patients with multiple sclerosis.

The endocannabinoid system (ECS) has been found altered in patients with multiple sclerosis (MS). However, whether the ECS alteration is present in the early stage of MS remains unknown. First, we aimed to compare the ECS profile between newly diagnosed MS patients and healthy controls (HCs). Next, we explored the association of the ECS, biomarkers of inflammation, and clinical parameters in newly diagnosed MS patients. Whole blood gene expression of ECS components and levels of endocannabinoids in plasma were measured by real-time quantitative polymerase chain reaction and ultra-high-pressure liquid chromatography-mass spectrometry, respectively, in 66 untreated MS patients and 46 HCs. No differences were found in the gene expression or plasma levels of the selected ECS components between newly diagnosed MS patients and HCs. Interferon-γ, encoded by the gene IFNG, correlated positively (ρ = 0.60) with the expression of G protein-coupled receptor 55 (GPR55), and interleukin1β (IL1B) correlated negatively (ρ = -0.50) with cannabinoid receptor 2 (CNR2) in HCs. We found no alteration in the peripheral ECS between untreated patients with MS and HC. Furthermore, our results indicate that the ECS has a minor overall involvement in the early stage of MS on inflammatory markers and clinical parameters when compared with HCs.

Predicting GPR40 Agonists with A Deep Learning-Based Ensemble Model.

Recent studies have identified G protein-coupled receptor 40 (GPR40) as a promising target for treating type 2 diabetes mellitus, and GPR40 agonists have several superior effects over other hypoglycemic drugs, including cardiovascular protection and suppression of glucagon levels. In this study, we constructed an up-to-date GPR40 ligand dataset for training models and performed a systematic optimization of the ensemble model, resulting in a powerful ensemble model (ROC AUC: 0.9496) for distinguishing GPR40 agonists and non-agonists. The ensemble model is divided into three layers, and the optimization process is carried out in each layer. We believe that these results will prove helpful for both the development of GPR40 agonists and ensemble models. All the data and models are available on GitHub. (https://github.com/Jiamin-Yang/ensemble_model).

Strain-level screening of human gut microbes identifies Blautia producta as a new anti-hyperlipidemic probiotic

ABSTRACT Compelling evidence has tightly linked gut microbiota with host metabolism homeostasis and inspired novel therapeutic potentials against metabolic diseases (e.g., hyperlipidemia). However, the regulatory profile of individual bacterial species and strain on lipid homeostasis remains largely unknown. Herein, we performed a large-scale screening of 2250 human gut bacterial strains (186 species) for the lipid-decreasing activity. Different strains in the same species usually displayed distinct lipid-modulatory actions, showing evident strain-specificity. Among the tested strains, Blautia producta exhibited the most potency to suppress cellular lipid accumulation and effectively ameliorated hyperlipidemia in high fat diet (HFD)-feeding mice. Taking a joint comparative approach of pharmacology, genomics and metabolomics, we identified an anteiso-fatty acid, 12-methylmyristic acid (12-MMA), as the key active metabolite of Bl. Producta. In vivo experiment confirmed that 12-MMA could exert potent hyperlipidemia-ameliorating efficacy and improve glucose metabolism via activating G protein-coupled receptor 120 (GPR120). Altogether, our work reveals a previously unreported large-scale lipid-modulatory profile of gut microbes at the strain level, emphasizes the strain-specific function of gut bacteria, and provides a possibility to develop microbial therapeutics against hyperlipidemia based on Bl. producta and its metabolite.

G-protein couple receptor (GPER1) plays an important role during ovarian folliculogenesis and early development of the Chinese Alligator

The critical role of the G protein-coupled receptor 1 (GPER1), a member of the seven-transmembrane G protein-coupled receptor family, in the functional regulation of oocytes accumulated abundant theories in the early research on model animals. However, the full-length cDNA encoding GPER1 and its role in the folliculogenesis has not been illustrated in crocodilians. 0.5, 3, and 12 months old Alligator sinensis cDNA samples were used to clone the full-length cDNA encoding GPER1. Immunolocalization and quantitative analysis were performed using Immunofluorescence technique, RT-PCR and Western blot. Simultaneously, studies on GPER1's promoter deletion and cis-acting transcriptional regulation mechanism were conducted. Immunolocalization staining for the germline marker DDX4 and GPER1 demonstrated that DDX4-positive oocytes were clustered tightly together within the nests, whereas scarcely any detectable GPER1 was present in the oocytes nest in Stage I. After that, occasionally GPER1-positive immunosignal was observed in oocytes and somatic cells additional with the primordial follicles, and it was mainly located at the granulosa cells or thecal cells within the early PFs in the Stage III. The single mutation of the putative SP1 motif, double mutating of Ets/SP1 and SP1/CRE binding sites all depressed promoter activities. This result will help to investigate the role of GPER1 in the early folliculogenesis of A. sinensis.

Bisphenol A increases the size of primary mammary tumors and promotes metastasis in a murine model of breast cancer

Triple negative breast cancer (TNBC) is a subtype of breast tumor characterized for the absence of estrogen and progesterone receptors expression and low HER2/neu expression. Bisphenol A (BPA) is an endocrine disrupting chemical with estrogenic activity that has been associated with increasing rates of breast cancer. Moreover, BPA is a solid organic synthetic chemical employed in the manufacture of many consumer products, epoxy resins and polycarbonate plastics including baby bottles, containers for food and beverages, and the lining of beverage cans. The G-protein-coupled estrogen receptor (GPER) is activated by endogenous hormones and synthetic ligands, such as BPA. GPER is expressed in TNBC cells and its expression is associated with larger tumor size, metastasis and worse survival prognosis. In breast cancer cells, BPA induces activation of signal transduction pathways that mediates migration and invasion via GPER in human TNBC MDA-MB-231 cells. In this study, we demonstrate that BPA induces an increase of GPER expression and its translocation from cytosol to cytoplasmic membrane, metalloproteinase (MMP)-2 and MMP-9 secretion, migration and invasion in murine TNBC 4T1 cells. In a murine TNBC model “in vivo” using 4T1 cells, BPA induces the formation of mammary tumors with more weight and volume, and an increase in the number of mice with metastasis to lung and nodules in lung compared with tumors and metastasis to lung of untreated Balb/cJ mice. In conclusion, our findings demonstrate that BPA mediates the growth of mammary primary tumors and metastasis to lung in a murine model of breast cancer.

GPER1 deficiency causes sex-specific dysregulation of hippocampal plasticity and cognitive function.

Estrogens regulate synaptic properties and influence hippocampus-related learning and memory via estrogen receptors, which include the G-protein-coupled estrogen receptor 1 (GPER1). Studying mice, in which the GPER1 gene is dysfunctional (GPER1-KO), we here provide evidence for sex-specific roles of GPER1 in these processes. GPER1-KO males showed reduced anxiety in the elevated plus maze, whereas the fear response ('freezing') was specifically increased in GPER1-KO females in a contextual fear conditioning paradigm. In the Morris water maze, spatial learning and memory consolidation was impaired by GPER1 deficiency in both sexes. Notably, in the females, spatial learning deficits and the fear response were more pronounced if mice were in a stage of the estrous cycle, in which E2 serum levels are high (proestrus) or rising (diestrus). On the physiological level, excitability at Schaffer collateral synapses in CA1 increased in GPER1-deficient males and in proestrus/diestrus ('E2 high') females, concordant with an increased hippocampal expression of the AMPA-receptor subunit GluA1 in GPER1-KO males and females as compared to wildtype males. Further changes included an augmented early long-term potentiation (E-LTP) maintenance specifically in GPER1-KO females and an increased hippocampal expression of spinophilin in metestrus/estrus ('E2 low') GPER1-KO females. Our findings suggest modulatory and sex-specific functions of GPER1 in the hippocampal network, which reduce rather than increase neuronal excitability. Dysregulation of these functions may underlie sex-specific cognitive deficits or mood disorders.