Progesterone-induced progesterone receptor membrane component 1 rise-to-decline changes are essential for decidualization.

BACKGROUND: Decidualization of endometrial cells is the prerequisite for embryo implantation and subsequent placenta formation and is induced by rising progesterone levels following ovulation. One of the hormone receptors contributing to endometrial homeostasis is Progesterone Receptor Membrane Component 1 (PGRMC1), a non-classical membrane-bound progesterone receptor with yet unclear function. In this study, we aimed to investigate how PGRMC1 contributes to human decidualization. METHODS: We first analyzed PGRMC1 expression profile during a regular menstrual cycle in RNA-sequencing datasets. To further explore the function of PGRMC1 in human decidualization, we implemented an inducible decidualization system, which is achieved by culturing two human endometrial stromal cell lines in decidualization-inducing medium containing medroxyprogesterone acetate and 8-Br-cAMP. In our system, we measured PGRMC1 expression during hormone induction as well as decidualization status upon PGRMC1 knockdown at different time points. We further conferred proximity ligation assay to identify PGRMC1 interaction partners. RESULTS: In a regular menstrual cycle, PGRMC1 mRNA expression is gradually decreased from the proliferative phase to the secretory phase. In in vitro experiments, we observed that PGRMC1 expression follows a rise-to-decline pattern, in which its expression level initially increased during the first 6 days after induction (PGRMC1 increasing phase) and decreased in the following days (PGRMC1 decreasing phase). Knockdown of PGRMC1 expression before the induction led to a failed decidualization, while its knockdown after induction did not inhibit decidualization, suggesting that the progestin-induced 'PGRMC1 increasing phase' is essential for normal decidualization. Furthermore, we found that the interactions of prohibitin 1 and prohibitin 2 with PGRMC1 were induced upon progestin treatment. Knocking down each of the prohibitins slowed down the decidualization process compared to the control, suggesting that PGRMC1 cooperates with prohibitins to regulate decidualization. CONCLUSIONS: According to our findings, PGRMC1 expression followed a progestin-induced rise-to-decline expression pattern during human endometrial decidualization process; and the correct execution of this expression program was crucial for successful decidualization. Thereby, the results of our in vitro model explained how PGRMC1 dysregulation during decidualization may present a new perspective on infertility-related diseases.

Hepatic progesterone receptor membrane component 1 attenuates ethanol-induced liver injury by reducing acetaldehyde production and oxidative stress.

Alcohol-associated liver disease (ALD) is caused by excessive abuse of alcohol. One of the most representative causes of ALD is the action of acetaldehyde. Acetaldehyde is a toxic material produced when alcohol is metabolized through some enzymes, and it causes endoplasmic reticulum (ER) stress, mitochondrial dysfunction, and tissue injury. In this study, we assessed the relationship between Progesterone receptor membrane component 1 (PGRMC1) and ALD because PGRMC1 is expressed in the ER and mitochondria in the liver. Using the chronic and binge alcohol feeding models, we assessed acetaldehyde level, liver damage, alcohol-degrading enzymes, and ER stress. Compared with wild-type (WT) mice ethanol-fed Pgrmc1 knockout (KO) mice had higher levels of alanine aminotransferase (ALT) and alcohol-degrading enzymes, and Pgrmc1 KO mice had high serum acetaldehyde and ER stress levels compared with WT mice with control and ethanol feeding. Loss of Pgrmc1 increased acetaldehyde production through increased expression of alcohol dehydrogenase and catalase, which led to increased ER stress and suggested that cell death was promoted. In conclusion, it has been proposed that the loss of PGRMC1 could promote ALD and cause liver damage in alcohol-abusing humans.NEW & NOTEWORTHY Loss of Pgrmc1 increased acetaldehyde production, and excess acetaldehyde consequently increased ER stress, which activates apoptosis. Since low expression of PGRMC1 is vulnerable to alcoholic liver damage, the loss of PGRMC1 expression may increase susceptibility to ALD.

Regulatory action of PGRMC1 on cyclic AMP-mediated COX2 expression in human endometrial cells.

Human endometrial stromal cells (ESCs) undergo differentiation, known as decidualization, and endometrial epithelial cells mature around the embryo implantation stage. In the uterus, cyclooxygenase 2 (COX2), the rate-limiting enzyme that produces prostaglandin E2, is expressed in endometrial stromal and epithelial cells, and promotes decidualization of the former cells. Our recent study demonstrated that progesterone receptor membrane component 1 (PGRMC1) is downregulated during decidualization and may be involved in cellular senescence associated with decidualization via the transcription factor forkhead box protein O1 (FOXO1). Therefore, we investigated the role of PGRMC1 in COX2 expression during differentiation and maturation of endometrial stromal and epithelial cells. Inhibition or knockdown of PGRMC1 significantly enhanced differentiation stimuli-induced COX2 expression in both cell types. However, this COX2 expression was suppressed by FOXO1 knockdown or nuclear factor-kappa B (NF-κB) inhibition. Silencing of COX2 expression inhibited PGRMC1 knockdown-induced expression of decidual markers in ESCs. Thus, PGRMC1 may be linked to FOXO1- and NF-κB-mediated COX2 expression in endometrial cells. Taken together, our data suggest that downregulation of PGRMC1 expression facilitates differentiation of endometrial cells, i.e., decidualization and glandular maturation, via upregulation of COX2 expression.

PGRMC1 promotes triple-negative breast cancer cell growth via suppressing ferroptosis.

OBJECTIVE: Triple-negative breast cancer (TNBC) is the most malignant form of breast cancer with increasing incidence and mortality worldwide. The progesterone receptor membrane component-1 (PGRMC1) is a well-identified hormone receptor with unknown functions in TNBC. The current study aims to explore the involvement of PGRMC1 in regulation of glutathione metabolism and ferroptosis during development of TNBC, providing new therapy options for TNBC patients. METHODS: Bioinformatic analysis, cell proliferation assay, western blot assay and other biochemistry methods were performed in TNBC cells. RESULTS: Our results revealed that the expression of PGRMC1 is higher in TNBC than the other subtypes of breast cancer. Interestingly, as an iron binding protein, increased PGRMC1 expression in TNBC cells leads to resistance to ferroptosis inducer. On the contrary, silenced PGRMC1 expression enhanced sensitivity of MDA-MB231 cells to Erastin. Mechanistically, overexpression of PGRMC1 decreased the intracellular free iron concentration, which was reduced by AG205 treatment. CONCLUSIONS: PGRMC1 increases the possibility of TNBC development through binding to intracellular iron and suppressing ferroptosis, providing the molecular basis of combined treatment for TNBC.

Overexpression of miR-181a regulates the Warburg effect in triple-negative breast cancer.

OBJECTIVE: Triple-negative breast cancer (TNBC) is highly aggressive and leads to a poor prognosis. microRNA-181a (miR-181a) exhibits strong antineoplastic effects in many types of cancer. In this study, we examine the responses of human miR-181a-transfected TNBC cells and explore the mechanisms underlying the observed effects. METHODS: A series of cellular assays were conducted using cells from the MDA-MB-231 TNBC line to assess the impact of miR-181a overexpression. The extracellular acidification rate, lactate production and glucose uptake were evaluated as a measure of aerobic glycolysis (i.e. the Warburg effect). The expressions of glycolysis-related gene were analyzed. RESULTS: Viability, migration and survival of miR-181a-transfected MDA-MB-231 cells were all significantly reduced. miR-181a inhibited glycolysis in TNBC cells by reducing the rates of glucose uptake and lactate production and a substantial downregulation of factors known to contribute to the Warburg effect, including the serine/threonine kinase, AKT3, hypoxia-inducible factor-1α (HIF-1α) and progesterone receptor membrane component 1 (PGRMC1). CONCLUSION: Our results demonstrate that miR-181a may regulate glycolysis in MDA-MB-231 TNBC cells, potentially via interference with components of the AKT3-HIF-1α and PGRMC1 pathways. These results suggest that miR-181a might be developed as a therapeutic agent for use in antineoplastic regimens directed at TNBC and PGRMC1-overexpressing breast cancers.

Dynamic transcriptome analysis of Maiwa yak corpus luteum during the estrous cycle.

Maiwa yak is a special breed of animal living on the Qinghai-Tibet Plateau, which has great economic value, but its fertility rate is low. The corpus luteum (CL) is a temporary tissue that plays a crucial role in maintaining the physiological cycle. However, little is known about the transcriptome profile in Maiwa yak CL. In the present study, the transcriptome of Maiwa yak CL at early (EYCL), middle (MYCL) and late-stages (LYCL) was studied employing high-throughput sequencing. A total of 25,922 transcripts were identified, including 22,277 known as well as 3,645 novel ones. Furthermore, 690 and 212 differentially expressed (DE) mRNAs were detected in the EYCL vs. MYCL and MYCL vs. LYCL groups, respectively. KEGG pathway enrichment analysis of DEGs illustrated that the most enriched pathway was PI3K-Akt pathway. Furthermore, twenty-six DEGs were totally found to be associated with different biological processes of CL development. One of these genes, PGRMC1, displayed a dynamical expression trend during the lifespan of yak CL. The knockdown of PGRMC1 in luteinized yak granulosa cells resulted in defective steroidogenesis. In conclusion, this study analyzed the transcriptome profiles in yak CL of different stages, and provided a novel database for analyzing the gene network in yak CL.HIGHLIGHTSThe manuscript analyzed the transcriptome profiles in yak CL during the estrous cycle.Twenty-six DEGs were found to be associated with the development or function of CL.One of the DEGs, PGRMC1, was found to be responsible for steroidogenesis in luteinized yak granulosa cells.

Sigma-2 Receptor Ligand Binding Modulates Association between TSPO and TMEM97.

Sigma-2 receptor (S2R) is a S2R ligand-binding site historically associated with reportedly 21.5 kDa proteins that have been linked to several diseases, such as cancer, Alzheimer's disease, and schizophrenia. The S2R is highly expressed in various tumors, where it correlates with the proliferative status of the malignant cells. Recently, S2R was reported to be the transmembrane protein TMEM97. Prior to that, we had been investigating the translocator protein (TSPO) as a potential 21.5 kDa S2R candidate protein with reported heme and sterol associations. Here, we investigate the contributions of TMEM97 and TSPO to S2R activity in MCF7 breast adenocarcinoma and MIA PaCa-2 (MP) pancreatic carcinoma cells. Additionally, the role of the reported S2R-interacting partner PGRMC1 was also elucidated. Proximity ligation assays and co-immunoprecipitation show a functional association between S2R and TSPO. Moreover, a close physical colocalization of TMEM97 and TSPO was found in MP cells. In MCF7 cells, co-immunoprecipitation only occurred with TMEM97 but not with PGRMC1, which was further confirmed by confocal microscopy experiments. Treatment with the TMEM97 ligand 20-(S)-hydroxycholesterol reduced co-immunoprecipitation of both TMEM97 and PGRMC1 in immune pellets of immunoprecipitated TSPO in MP cells. To the best of our knowledge, this is the first suggestion of a (functional) interaction between TSPO and TMEM97 that can be affected by S2R ligands.

Sigma-2 Receptors-From Basic Biology to Therapeutic Target: A Focus on Age-Related Degenerative Diseases.

There is a large unmet medical need to develop disease-modifying treatment options for individuals with age-related degenerative diseases of the central nervous system. The sigma-2 receptor (S2R), encoded by TMEM97, is expressed in brain and retinal cells, and regulates cell functions via its co-receptor progesterone receptor membrane component 1 (PGRMC1), and through other protein-protein interactions. Studies describing functions of S2R involve the manipulation of expression or pharmacological modulation using exogenous small-molecule ligands. These studies demonstrate that S2R modulates key pathways involved in age-related diseases including autophagy, trafficking, oxidative stress, and amyloid-ß and α-synuclein toxicity. Furthermore, S2R modulation can ameliorate functional deficits in cell-based and animal models of disease. This review summarizes the current evidence-based understanding of S2R biology and function, and its potential as a therapeutic target for age-related degenerative diseases of the central nervous system, including Alzheimer's disease, α-synucleinopathies, and dry age-related macular degeneration.

E2 + norethisterone promotes the PI3K-AKT pathway via PGRMC1 to induce breast cancer cell proliferation.

OBJECTIVE: This study aimed to find evidence that progesterone receptor membrane component 1 (PGRMC1) promotes estradiol (E2) + norethisterone (NET)-induced breast cancer proliferation through activation of the phosphatidylinositol-3-kinase (PI3K)-AKT pathway. METHODS: PGRMC1-mediated breast cancer cellular proliferation and phosphorylation of PGRMC1 were studied using wild-type (hemagglutinin [HA]-tagged) MCF-7 cells, which were stably transfected with expression vector containing HA (MCF-7-HA cells), PGRMC1 (MCF-7-PGRMC1 cells) and Ser181 point mutated PGRMC1 (MCF-7-PGRMC1-S181A cells). Bioinformatics, cell proliferation, western blot, isobaric tags for relative and absolute quantitation (iTRAQ)-based RNA sequencing, real-time quantitative polymerase chain reaction (RT-qPCR) and cell cycle in vitro assays were performed to indicate the function of PGRMC1 and its possible mechanisms in breast cancer. RESULTS: NET + E2 elicited a significant proliferation in MCF-7-Vec at 10-6 M and 10-10 M, respectively. MCF-7-PGRMC1 did increase the phosphorylation of AKT or ERK, which can be blocked by treatment with casein kinase 2 (CK2) inhibitor quinalizarin or in MCF-7-PGRMC1-S181A cells. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that the PI3K-AKT pathway is upregulated in MCF-7-PGRMC1 cells. Importantly, upregulation of the PI3K-AKT pathway mainly through promotion of cell cycle regulation strongly promoted cell proliferation in MCF-7-PGRMC1 cells. CONCLUSIONS: CK2 is involved in phosphorylation of PGRMC1 at S181. The mechanism for the action of PGRMC1 for mediating proliferative progestogen effects obviously starts with promotion cell cycle regulation, and then activation of the PI3K-AKT pathway.

Progesterone receptor membrane components: key regulators of fetal membrane integrity.

Pro-pregnancy hormone progesterone (P4) helps to maintain a quiescent status of uterine tissues during gestation. However, P4's functional role in maintaining fetal membrane (amniochorion) integrity remains unclear. P4 functions through its membrane receptors (progesterone receptor membrane components (PGRMCs)) as fetal membrane cells lack nuclear receptors. This study screened the differential expression of PGRMCs in the fetal membranes and tested P4-PGRMC interactions under normal and oxidative stress (OS) conditions expected that can disrupt P4-PGRMC interactions impacting fetal membrane stability resulting in parturition. Human fetal membranes were collected from term and preterm deliveries (N = 5). Immunohistochemistry and western blot localized and determined differential expression of P4 receptors. Primary amnion epithelial, mesenchymal (AMCs), and chorion cell were treated with P4 alone or co-treated (P4 + OS induced by cigarette smoke extract (CSE)). Proximity ligation assay (PLA) documented P4-receptor binding, whereas P4 enzyme-linked immunosorbent assay documented culture supernatant levels. Immunohistology confirmed lack of nuclear progesterone receptors; however, confirmed expressions of PGRMC 1 and 2. Term labor (P = 0.01) and preterm rupture (P = 0.01) are associated with significant downregulation of PGRMC2. OS-induced differential downregulation of PGRMCs in both amnion and chorion cells (all P < 0.05) and downregulates P4 release (AMCs; P = 0.01). The PLA showed preferential receptor-ligand binding in amnion and chorion cells. Co-treatment of P4 + CSE did not reverse CSE-induced effects. In conclusion, P4-PGRMCs interaction maintains fetal membranes' functional integrity throughout pregnancy. Increased OS reduces endogenous P4 production and cell type-dependent downregulation of PGRMCs. These changes can lead to fetal membrane-specific "functional progesterone withdrawal," contributing to the dysfunctional fetal membrane status seen at term and preterm conditions.

Absence of progesterone receptor membrane component 1 reduces migration and metastasis of breast cancer.

BACKGROUND: Progesterone receptor membrane component 1 (Pgrmc1) is a non-classical progesterone receptor associated with the development of the mammary gland and xenograft-induced breast cancer. Importantly, Pgrmc1 is associated with the expression of estrogen receptor alpha and can be used for predicting the prognosis of breast cancer. Whether the genetic deletion of Pgrmc1 affects the progression of breast cancer is still unclear. METHODS: We used MMTV-PyMT transgenic mice that spontaneously develop breast tumors. In backcrossed FVB Pgrmc1 knockout (KO) mice, we monitored the development of the primary tumor and lung metastasis. In MCF-7 and MDA-MB-231 tumor cell lines, the migratory activity was evaluated after Pgrmc1 knockdown. RESULTS: There was no significant difference in the development of breast cancer in terms of tumor size at 13 weeks of age between WT and Pgrmc1 KO mice. However, Pgrmc1 KO mice had a significantly longer survival duration compared with WT mice. Furthermore, Pgrmc1 KO mice exhibited a significantly lower degree of lung metastasis. Compared with those of WT mice, the tumors of Pgrmc1 KO mice had a low expression of focal adhesion kinase and epithelial-mesenchymal transition markers. PGRMC1 knockdown resulted in a significantly reduced migration rate in breast cancer cell lines. CONCLUSIONS: Pgrmc1 KO mice with breast cancer had a prolonged survival, which was accompanied by a low degree of lung metastasis. PGRMC1 showed a significant role in the migration of breast cancer cells, and may serve as a potential therapeutic target in breast cancer. Video Abstract.

Let-7i inhibition enhances progesterone-induced functional recovery in a mouse model of ischemia.

Progesterone (P4) is a potent neuroprotectant and a promising therapeutic for stroke treatment. However, the underlying mechanism(s) remain unclear. Our laboratory recently reported that brain-derived neurotrophic factor (BDNF) is a critical mediator of P4's protective actions and that P4-induced BDNF release from cortical astrocytes is mediated by a membrane-associated progesterone receptor, Pgrmc1. Here, we report that the microRNA (miRNA) let-7i is a negative regulator of Pgrmc1 and BDNF in glia and that let-7i disrupts P4-induced BDNF release and P4's beneficial effects on cell viability and markers of synaptogenesis. Using an in vivo model of ischemia, we demonstrate that inhibiting let-7i enhances P4-induced neuroprotection and facilitates functional recovery following stroke. The discovery of such factors that regulate the cytoprotective effects of P4 may lead to the development of biomarkers to differentiate/predict those likely to respond favorably to P4 versus those that do not.

Systematic and standardized comparison of reported amyloid-ß receptors for sufficiency, affinity, and Alzheimer's disease relevance.

Oligomeric assemblies of amyloid-ß (Aß) peptide (Aßo) in the brains of individuals with Alzheimer's disease (AD) are toxic to neuronal synapses. More than a dozen Aß receptor candidates have been suggested to be responsible for various aspects of the molecular pathology and memory impairment in mouse models of AD. A lack of consistent experimental design among previous studies of different receptor candidates limits evaluation of the relative roles of these candidates, producing some controversy within the field. Here, using cell-based assays with several Aß species, including Aßo from AD brains obtained by autopsy, we directly compared the Aß-binding capacity of multiple receptor candidates while accounting for variation in expression and confirming cell surface expression. In a survey of 15 reported Aß receptors, only cellular prion protein (PrPC), Nogo receptor 1 (NgR1), and leukocyte immunoglobulin-like receptor subfamily B member 2 (LilrB2) exhibited direct binding to synaptotoxic assemblies of synthetic Aß. Both PrPC and NgR1 preferentially bound synaptotoxic oligomers rather than nontoxic monomers, and the method of oligomer preparation did not significantly alter our binding results. Hippocampal neurons lacking both NgR1 and LilrB2 exhibited a partial reduction of Aßo binding, but this reduction was lower than in neurons lacking PrPC under the same conditions. Finally, binding studies with soluble Aßo from human AD brains revealed a strong affinity for PrPC, weak affinity for NgR1, and no detectable affinity for LilrB2. These findings clarify the relative contributions of previously reported Aß receptors under controlled conditions and highlight the prominence of PrPC as an Aß-binding site.

Progesterone receptor membrane component 1 regulates lipid homeostasis and drives oncogenic signaling resulting in breast cancer progression.

BACKGROUND: PGRMC1 (progesterone receptor membrane component 1) is a highly conserved heme binding protein, which is overexpressed especially in hormone receptor-positive breast cancer and plays an important role in breast carcinogenesis. Nevertheless, little is known about the mechanisms by which PGRMC1 drives tumor progression. The aim of our study was to investigate the involvement of PGRMC1 in cholesterol metabolism to detect new mechanisms by which PGRMC1 can increase lipid metabolism and alter cancer-related signaling pathways leading to breast cancer progression. METHODS: The effect of PGRMC1 overexpression and silencing on cellular proliferation was examined in vitro and in a xenograft mouse model. Next, we investigated the interaction of PGRMC1 with enzymes involved in the cholesterol synthesis pathway such as CYP51, FDFT1, and SCD1. Further, the impact of PGRMC1 expression on lipid levels and expression of enzymes involved in lipid homeostasis was examined. Additionally, we assessed the role of PGRMC1 in key cancer-related signaling pathways including EGFR/HER2 and ERα signaling. RESULTS: Overexpression of PGRMC1 resulted in significantly enhanced proliferation. PGRMC1 interacted with key enzymes of the cholesterol synthesis pathway, alters the expression of proteins, and results in increased lipid levels. PGRMC1 also influenced lipid raft formation leading to altered expression of growth receptors in membranes of breast cancer cells. Analysis of activation of proteins revealed facilitated ERα and EGFR activation and downstream signaling dependent on PGRMC1 overexpression in hormone receptor-positive breast cancer cells. Depletion of cholesterol and fatty acids induced by statins reversed this growth benefit. CONCLUSION: PGRMC1 may mediate proliferation and progression of breast cancer cells potentially by altering lipid metabolism and by activating key oncogenic signaling pathways, such as ERα expression and activation, as well as EGFR signaling. Our present study underlines the potential of PGRMC1 as a target for anti-cancer therapy.

Downregulation of nuclear progestin receptor (Pgr) and subfertility in double knockouts of progestin receptor membrane component 1 (pgrmc1) and pgrmc2 in zebrafish.

The progestin receptor membrane components (Pgrmcs) contain two paralogs, Pgrmc1 and Pgrmc2. Our previous research into single knockout of Pgrmc1 or Pgrmc2 suggests that Pgrmc1 and Pgrmc2 regulate membrane progestin receptor or steroid synthesis and therefore female fertility in zebrafish. Additional roles of Pgrmcs may not be determined in using single Pgrmc knockouts due to compensatory roles between Pgrmc1 and Pgrmc2. To address this question, we crossed single knockout pgrmc1 (pgrmc1-/-) with pgrmc2 (pgrmc2-/-), and generated double knockouts for both pgrmc1 and pgrmc2 (pgrmc1/2-/-) in a vertebrate model, zebrafish. In addition to the delayed oocyte maturation and reduced female fertility, significant reduced ovulation was found in double knockout (pgrmc1/2-/-) in vivo, though not detected in either single knockout of Pgrmc (pgrmc1-/- or pgrmc2-/-). We also found significant down regulation of nuclear progestin receptor (Pgr) protein expression only in pgrmc1/2-/-, which was most likely the cause of reduced ovulation. Lower protein expression of Pgr also resulted in reduced expression of metalloproteinase in pgrmc1/2-/-. With this study, we have provided new evidence for the physiological functions of Pgrmcs in the regulation of female fertility by regulation of ovulation, likely via regulation of Pgr, which affects regulation of metalloproteinase expression and oocyte ovulation.

PGRMC1 in animal breast cancer tissue and blood is associated with increased tumor growth with norethisterone in contrast to progesterone and dydrogesterone: four-arm randomized placebo-controlled xenograft study.

Progesterone receptor membrane component 1 (PGRMC1) is mediating strong breast cancer cell proliferation induced by certain synthetic progestogens which we have shown within already published in vitro studies. Aim was now to use an animal model, to compare tumor growth using progesterone and its isomer dydrogesterone with norethisterone, which elicited in our in vitro studies the strongest proliferating effect. For the first time, we wanted to investigate if growth can be correlated both with blood concentrations and tissue expression of PGRMC1 to identify if PGRMC1 could be a new tumor marker. Prospective, randomized, blinded, placebo-controlled four-arm study (45-50 days); PGRMC1-transfected or empty-vector T47D- and MCF7-xenotransplants were each treated with estradiol (E2) +placebo; E2 + progesterone; E2 + norethisterone; E2 + dydrogesterone; blood PGRMC1 assessed by a novel ELISA, tissue expression by immunohistochemistry. PGRMC1-transfected tumors further increased with E2 + norethisterone but not with E2-dydrogesterone or E2-progesterone. In both PGRMC1-xenograft groups (T47D, MCF7) with E2/norethisterone, the blood concentrations and tissue expression of PGRMC1 were higher than in all other 14 groups (p < .05), with positive significant correlation between blood PGRMCI concentrations and tissue PGRMC1 expression. In the presence of PGRMC1, certain progestogens could increase the growth of breast tumor, which now also should be tested in clinical studies.

PGRMC1 Inhibits Progesterone-Evoked Proliferation and Ca2+ Entry Via STIM2 in MDA-MB-231 Cells.

Progesterone receptor membrane component 1 (PGRMC1) has been shown to regulate some cancer hallmarks. Progesterone (P4) evokes intracellular calcium (Ca2+) changes in the triple-negative breast cancer cell lines (MDA-MB-231, MDA-MB-468, and BT-20) and in other breast cancer cell lines like the luminal MCF7 cells. PGRMC1 expression is elevated in MDA-MB-231 and MCF7 cells as compared to non-tumoral MCF10A cell line, and PGRMC1 silencing enhances P4-evoked Ca2+ mobilization. Here, we found a new P4-dependent Ca2+ mobilization pathway in MDA-MB-231 cells and other triple-negative breast cancer cells, as well as in MCF7 cells that involved Stromal interaction molecule 2 (STIM2), Calcium release-activated calcium channel protein 1 (Orai1), and Transient Receptor Potential Channel 1 (TRPC1). Stromal interaction molecule 1 (STIM1) was not involved in this novel Ca2+ pathway, as evidenced by using siRNA STIM1. PGRMC1 silencing reduced the negative effect of P4 on cell proliferation and cell death in MDA-MB-231 cells. In line with the latter observation, Nuclear Factor of Activated T-Cells 1 (NFAT1) nuclear accumulation due to P4 incubation for 48 h was enhanced in cells transfected with the small hairpin siRNA against PGRMC1 (shPGRMC1). These results provide evidence for a novel P4-evoked Ca2+ entry pathway that is downregulated by PGRMC1.

Progesterone maintains the status of granulosa cells and slows follicle development partly through PGRMC1.

Progesterone receptor membrane component 1 (PGRMC1) mediates antimitotic and antiapoptotic actions of progesterone in granulosa cells, which indicates that PGRMC1 may play a key role in maintaining the status of granulosa cells. The current study investigated the effects of progesterone on intracellular signaling involved in differentiation, follicle development, inflammatory responses, and antioxidation, and determined the role of PGRMC1 in these processes. Our results demonstrated that progesterone slowed follicle development and inhibited p-ERK1/2, p-p38, caspase-3, p-NF-κB, and p-IκB-α signals involved in differentiation, steroidogenesis, and inflammatory responses in granulosa cells. Progesterone inhibited the steroidogenic acute regulatory protein and the cholesterol side-chain cleavage enzyme and decreased pregnenolone production. A PGRMC1 inhibitor and a PGRMC1 small interfering RNA ablated these inhibitory effects of progesterone. Interfering with PGRMC1 functions also decreased cellular antioxidative effects induced by an oxidant. These results suggest that PGRMC1 might play a critical role in maintaining the status of granulosa cells and balancing follicle numbers.

Roles of progesterone receptor membrane component 1 and membrane progestin receptor alpha in regulation of zebrafish oocyte maturation.

Although previous studies suggest membrane progesterone receptor alpha (mPRα/Paqr7) mediates 17, 20ß-dihydroxy-4-pregnen-3-one (DHP) induction of oocyte maturation (OM) in zebrafish, critical information needed to establish mPRα as the receptor mediating OM is lacking. The relative potencies of progestins and specific mPRα agonists in inducing OM matched their relative binding affinities for zebrafish mPRα, supporting its role in OM. Microinjection of pertussis toxin blocked DHP induction of OM and the progestin-induced decrease in cyclic AMP levels, suggesting mPRα activates an inhibitory G protein (Gi). Microinjection of morpholino antisense oligonucleotides to zebrafish pgrmc1 blocked induction of OM by DHP which was accompanied by decreased levels of Pgrmc1 and mPRα on the oocyte plasma membranes. Similarly, treatment of denuded oocytes with a PGRMC1 inhibitor, AG205, blocked the gonadotropin-induced increase in plasma membrane mPRα levels and attenuated DHP induction of OM. Co-incubation with two inhibitors of epidermal growth factor Erbb2, ErbB2 inhibitor II and AG 879, prevented induction of OM by DHP, indicating the likely involvement of Erbb2 in mPRα-mediated signaling. Treatment with AG205 reversed the inhibitory effects of the Erbb2 inhibitors on OM and also inhibited insulin-like growth factor-1 induction of OM. Close associations between Pgrmc1 and mPRα, and between Pgrmc1 and Erbb2 were detected in zebrafish oocytes with in situ proximity ligation assays. The results suggest progestin induction of OM in zebrafish is mediated through an mPRα/Gi/Erbb2 signaling pathway that requires Pgrmc1 for expression of mPRα on oocyte membranes and that Pgrmc1 also is required for induction of OM through Erbb2.

Small molecule modulator of sigma 2 receptor is neuroprotective and reduces cognitive deficits and neuroinflammation in experimental models of Alzheimer's disease.

Accumulating evidence suggests that modulating the sigma 2 receptor (Sig2R) can provide beneficial effects for neurodegenerative diseases. Herein, we report the identification of a novel class of Sig2R ligands and their cellular and in vivo activity in experimental models of Alzheimer's disease (AD). We report that SAS-0132 and DKR-1051, selective ligands of Sig2R, modulate intracellular Ca2+ levels in human SK-N-SH neuroblastoma cells. The Sig2R ligands SAS-0132 and JVW-1009 are neuroprotective in a C. elegans model of amyloid precursor protein-mediated neurodegeneration. Since this neuroprotective effect is replicated by genetic knockdown and knockout of vem-1, the ortholog of progesterone receptor membrane component-1 (PGRMC1), these results suggest that Sig2R ligands modulate a PGRMC1-related pathway. Last, we demonstrate that SAS-0132 improves cognitive performance both in the Thy-1 hAPPLond/Swe+ transgenic mouse model of AD and in healthy wild-type mice. These results demonstrate that Sig2R is a promising therapeutic target for neurocognitive disorders including AD.