Progesterone Receptor Membrane Component Research Articles

Pleiotropy of Progesterone Receptor Membrane Component 1 in Modulation of Cytochrome P450 Activity

Progesterone receptor membrane component 1 (PGRMC1) is one of few proteins that have been recently described as direct modulators of the activity of human cytochrome P450 enzymes (CYP)s. These enzymes form a superfamily of membrane-bound hemoproteins that metabolize a wide variety of physiological, dietary, environmental, and pharmacological compounds. Modulation of CYP activity impacts the detoxification of xenobiotics as well as endogenous pathways such as steroid and fatty acid metabolism, thus playing a central role in homeostasis. This review is focused on nine main topics that include the most relevant aspects of past and current PGRMC1 research, focusing on its role in CYP-mediated drug metabolism. Firstly, a general overview of the main aspects of xenobiotic metabolism is presented (I), followed by an overview of the role of the CYP enzymatic complex (IIa), a section on human disorders associated with defects in CYP enzyme complex activity (IIb), and a brief account of cytochrome b5 (cyt b5)’s effect on CYP activity (IIc). Subsequently, we present a background overview of the history of the molecular characterization of PGRMC1 (III), regarding its structure, expression, and intracellular location (IIIa), and its heme-binding capability and dimerization (IIIb). The next section reflects the different effects PGRMC1 may have on CYP activity (IV), presenting a description of studies on the direct effects on CYP activity (IVa), and a summary of pathways in which PGRMC1’s involvement may indirectly affect CYP activity (IVb). The last section of the review is focused on the current challenges of research on the effect of PGRMC1 on CYP activity (V), presenting some future perspectives of research in the field (VI).

Beyond Hormones: Investigating the Impact of Progesterone Receptor Membrane Component 1 in Lung Adenocarcinoma.

Progesterone Receptor Membrane Component 1 (PGRMC1) is a candidate oncogene with a prominent involvement in the pathogenesis of diverse cancers (ovarian, thyroid, breast, colon, head, and neck). Our study ascertains the ability of PGRMC1 to influence WNT members in the non-small cell lung cancer subtype-lung adenocarcinoma (LUAD) and participates in augmented cell proliferation and migration. Both computational and in vitro experimental analyses were performed in this study. Gene silencing, in vitro assays, gene expression & and protein expression studies were performed to ascertain the role of PGRMC1 in LUAD cells. The computational analysis, PGRMC1 gene level expression was analysed using the microarray gene expression omnibus datasets (GSE27262; GSE18842) to compare LUAD tumours and normal tissues. Concurrently, the gene expression profiling interactive analysis of PGRMC1 and Kaplan-Meier survival analysis revealed a decreasing patient survival rate with an increasing PGRMC1 gene expression in LUAD tumour samples. Interestingly, the experimental gene silencing studies were conducted in vitro (si-PGRMC1 Vs si-Control) to understand the essential role of PGRMC1 in regulating WNT-associated genes (WNT1, WNT5A, and WNT11). Comparative experimental cell migration and spheroid formation assays (si-PGRMC1 Vs si-Control) in vitro showed a strong association between PGRMC1 and LUAD. In vitro expression analysis using real-time PCR and western blot further confirmed the connecting link between PGRMC1 and WNT5A compared to other WNT member genes (WNT1 and WNT11) in LUAD. The computational and experimental analyses agreed with one another.

Progesterone-mediated remodeling of the maternal-fetal interface by a PGRMC1-dependent mechanism

Implantation and maintenance of pregnancy involve intricate immunological processes that enable the developing fetus to coexist with the maternal immune system. Progesterone, a critical hormone during pregnancy, is known to promote immune tolerance and prevent preterm labor. However, the mechanism by which progesterone mediates these effects remains unclear. In this study, we investigated the role of the non-classical progesterone receptor membrane component 1 (PGRMC1) in progesterone signaling at the maternal-fetal interface. Using JEG3 cells, a trophoblast model cell line, we observed that progesterone stimulation increased the expression of human leukocyte antigen-C (HLA-C) and HLA-G, key molecules involved in immune tolerance. We also found that progesterone upregulated the expression of the transcription factor ELF3, which is known to regulate trophoblast-specific HLA-C expression. Interestingly, JEG3 cells lacked expression of classical progesterone receptors (PRs) but exhibited high expression of PGRMC1, a finding we confirmed in primary trophoblasts by mining sc-RNA seq data from human placenta. To investigate the role of PGRMC1 in progesterone signaling, we used CRISPR/Cas9 technology to knockout PGRMC1 in JEG3 cells. PGRMC1-deficient cells showed a diminished response to progesterone stimulation. Furthermore, we found that the progesterone antagonist RU486 inhibited ELF3 expression in a PGRMC1-dependent manner, suggesting that RU486 acts as a progesterone antagonist by competing for receptor binding. Additionally, we found that RU486 inhibited cell invasion, an important process for successful pregnancy, and this inhibitory effect was dependent on PGRMC1. Our findings highlight the crucial role of PGRMC1 in mediating the immunoregulatory effects of progesterone at the maternal-fetal interface.

Preclinical Targeting of the PGRMC1-CK2 Axis with Silmitasertib: A Potential Strategy for Lung Adenocarcinoma Therapy.

Progesterone receptor membrane component 1 (PGRMC1) is a pleiotropic protein over-expressed in lung adenocarcinoma (LUAD). The precise molecular mechanisms underlying the signature motif of Casein kinase (CK2) presence in PGRMC1 and their role in LUAD remain unclear. X-ray crystallographic structure for CK2 and PGRMC1 from the PubChem database was obtained and subjected to protein-protein interaction (PPI) analysis to identify their interactions. In addition, the CK2 inhibitor - Silmitasertib was also utilised to understand the interaction between PGRMC1-CK2. The PPI complex (PGRMC1-CK2) and the PPI-ligand interaction analysis and their Molecular Dynamics (MD) studies revealed the stability of their interactions and critical amino acid contacts within the 5Ǻ vicinity of the CK2 signature motif "T/S-x-x-E/D". Moreover, in-vitro colony formation assay, migration assay, and gene expression analysis using quantitative Real-time PCR revealed that Silmitasertib (IC50-2.5 μM) was highly influential in suppressing the PGRMC1-CK2 expression axis. In conclusion, our study infers that PGRMC1-CK-2 axis inhibition could be a potential therapeutic option to limit the promotion and progression of lung cancer.

Defining Requirements for Heme Binding in PGRMC1 and Identifying Key Elements that Influence Protein Dimerization.

Progesterone receptor membrane component 1 (PGRMC1) binds heme via a surface-exposed site and displays some structural resemblance to cytochrome b5 despite their different functions. In the case of PGRMC1, it is the protein interaction with drug-metabolizing cytochrome P450s and the epidermal growth factor receptor that has garnered the most attention. These interactions are thought to result in a compromised ability to metabolize common chemotherapy agents and to enhance cancer cell proliferation. X-ray crystallography and immunoprecipitation data have suggested that heme-mediated PGRMC1 dimers are important for facilitating these interactions. However, more recent studies have called into question the requirement of heme binding for PGRMC1 dimerization. Our study employs spectroscopic and computational methods to probe and define heme binding and its impact on PGRMC1 dimerization. Fluorescence, electron paramagnetic resonance and circular dichroism spectroscopies confirm heme binding to apo-PGRMC1 and were used to demonstrate the stabilizing effect of heme on the wild-type protein. We also utilized variants (C129S and Y113F) to precisely define the contributions of disulfide bonds and direct heme coordination to PGRMC1 dimerization. Understanding the key factors involved in these processes has important implications for downstream protein-protein interactions that may influence the metabolism of chemotherapeutic agents. This work opens avenues for deeper exploration into the physiological significance of the truncated-PGRMC1 model and developing design principles for potential therapeutics to target PGRMC1 dimerization and downstream interactions.

Deciphering the role of PGRMC2 in the human endometrium during the menstrual cycle and in vitro decidualization using an in vitro approach.

What is the human endometrial non-classical progesterone receptor (PGR) membrane component 2 (PGRMC2) expression pattern throughout the menstrual cycle and what role does it play during decidualization? Endometrial PGRMC2 expression fluctuates during the human menstrual cycle and is abundantly expressed in human endometrial stromal cells (hEnSCs) during in vitro decidualization, process where PGRMC2 is involved in embryo implantation-related pathways. The endometrial response to progesterone is mediated by the classical and non-classical PGRs. We previously demonstrated that PGR membrane component 1 (PGRMC1) is critical for endometrial function, embryo implantation, and future placentation, however, the role(s) of PGRMC2, which is structurally similar to PGRMC1, have not been studied in the human endometrium. This prospective study comprehensively evaluated the endometrial expression of PGRMC2 throughout the human menstrual cycle and during in vitro decidualization of hEnSCs (isolated from 77 endometrial biopsies that were collected from 66 oocyte donors), using immunohistochemistry, RT-qPCR, western blot, transcriptomic, and proteomic analyses. In addition, functional analysis was carried out to validate the implication of PGRMC2 in hEnSCs during embryo invasion using an in vitro outgrowth model. In vitro decidualization of hEnSCs was induced using co-treatment with cAMP and medroxyprogesterone 17-acetate progestin, and evaluated by measuring prolactin by ELISA and F-actin immunostaining. RT-qPCR was employed to compare expression with other PGRs. To reveal the function of PGRMC2 during the decidualization process, we specifically knocked down PGRMC2 with siRNAs and performed RNA-seq and quantitative proteomics techniques (SWATH-MS). The common differentially expressed genes (DEGs) and proteins (DEPs) were considered for downstream functional enrichment analysis. Finally, to verify its implication in the trophoblast invasion, an outgrowth model was carried out where hEnSCs with silenced PGRMC2 were co-cultured with human trophoblastic spheroids (JEG-3) following in vitro decidualization. In contrast to PGRMC1 and classical PGRs, endometrial PGRMC2 gene expression was significantly lower during the late- versus mid-secretory phase (P < 0.05). Accordingly, the elevated PGRMC2 protein abundance observed in the endometrial epithelial glands throughout the menstrual cycle dropped in the late secretory phase, when abundance decreased in all endometrial compartments. Nevertheless, PGRMC2 protein increased during the mid-secretory phase in stromal and glandular cells, and PGRMC2 mRNA (P < 0.0001) and protein (P < 0.001) levels were significantly enhanced in the membranes/organelles of decidualized hEnSCs, compared to non-decidualized hEnSCs. Notably, PGRMC1 and PGRMC2 mRNA were significantly more abundant than classical PGRs throughout menstrual cycle phases and in decidualized and non-decidualized hEnSCs (P < 0.05). RNA-seq and proteomics data revealed 4687 DEGs and 28 DEPs, respectively, in decidualized hEnSCs after PGRMC2 silencing. While functional enrichment analysis showed that the 2420 upregulated genes were mainly associated with endoplasmic reticulum function, vesicular transport, morphogenesis, angiogenesis, cell migration, and cell adhesion, the 2267 downregulated genes were associated with aerobic respiration and protein biosynthesis. The protein enrichment analysis showed that 4 upregulated and 24 downregulated proteins were related to aerobic respiration, cellular response, metabolism, localization of endoplasmic reticulum proteins, and ribonucleoside biosynthesis routes. Finally, PGRMC2 knockdown significantly compromised the ability of the decidualized hEnSCs to support trophoblast expansion in an outgrowth model (P < 0.05). Transcriptomic data are available via NCBI's Gene Expression Omnibus (GEO) under GEO Series accession number GSE251843 and proteomic data via ProteomeXchange with identifier PXD048494. The functional analyses were limited by the discrete number of human endometrial biopsies. A larger sample size is required to further investigate the potential role(s) of PGRMC2 during embryo implantation and maintenance of pregnancy. Further, the results obtained in the present work should be taken with caution, as the use of a pure primary endometrial stromal population differentiated in vitro does not fully represent the heterogeneity of the endometrium in vivo, nor the paracrine communications occurring between the distinct endometrial cell types. The repression of endometrial PGRMC2 during the late- versus mid-secretory phase, together with its overexpression during decidualization and multiple implications with embryo implantation not only highlighted the unknown roles of PGRMC2 in female reproduction but also the potential to exploit PGRMC2 signaling pathways to improve assisted reproduction treatments in the future. This research was funded by Instituto de Salud Carlos III (ISCIII) granted to F.D. (PI20/00405 and PI23/00860), co-funded by the European Union. Y.M.-L. was supported by a predoctoral research grant from Generalitat Valenciana (ACIF/2019/262). R.G.-M. was supported by Generalitat Valenciana (CIAPOT/2022/15). P.d.C. was supported by a predoctoral grant for training in research into health (PFIS FI20/00086) from the Instituto de Salud Carlos III. I.D.-H. was supported by the Spanish Ministry of Science, Innovation and Universities (FPU18/01550). A.P. was supported by the Instituto de Salud Carlos III (PFIS FI18/00009). This research was also supported by IVI Foundation-RMA Global (1911-FIVI-103-FD). The authors declare no conflict of interest.

Progesterone Receptor Membrane Component 1 Regulates Cellular Stress Responses and Inflammatory Pathways in Chronic Neuroinflammatory Conditions.

Alzheimer's disease (AD) is the leading cause of dementia and is one of the neurodegenerative diseases that are caused by neuronal death due to various triggers. Neuroinflammation plays a critical role in the development of AD. The neuroinflammatory response is manifested by pro-inflammatory cytokines, such as interleukin (IL)-1β, IL-6, and tumor necrosis factor-α; various chemokines; nitrous oxide; and reactive oxygen species. In this study, we evaluated the relevance of progesterone receptor membrane component 1 (PGRMC1), which is expressed in the brain cells during the induction of neuroinflammation. A lipopolysaccharide (LPS)-induced chronic neuroinflammation model and Pgrmc1 knockdown cells were used to assess the inflammatory cytokine levels, AD-related factors, inflammation-related signaling, and cell death. Pgrmc1 knockout (KO) mice had higher IL-1β levels after treatment with LPS compared with those of wild-type (WT) mice. Furthermore, Pgrmc1 KO mice had higher levels of inflammatory factors, endoplasmic reticulum stress indicators, and AD-associated markers compared with those of WT mice who underwent LPS treatment or not. Finally, these indicators were observed in vitro using U373-MG astrocytes. In conclusion, the loss of PGRMC1 may promote neuroinflammation and lead to AD.

B-GOS alleviates olanzapine-induced lipid disturbances in mice by enriching Akkermansia and upregulation of PGRMC1-Wnt signaling

Although olanzapine (OLZ) remains one of the most efficacious antipsychotic medications for the treatment of schizophrenia, there are significant tolerability issues related to its metabolic profile such as weight gain and dyslipidemia. Our previous studies have demonstrated that progesterone receptor membrane component 1 (PGRMC1) plays a key role in antipsychotic-induced metabolic side effects. Prebiotics showed positive effects on lipid metabolism, however, limited studies focused on their therapeutic potential and mechanisms in treating antipsychotic-induced lipid metabolic disorders. Herein, our study aims to explore the effects of the prebiotic B-GOS on lipid disturbances induced by OLZ and elucidate its underlying mechanisms via PGRMC1 pathway. In an 8-week study, long-term intraperitoneal administration of OLZ at a dosage of 8 mg/kg/day in mice induced lipid disturbances as manifested by significantly increased lipid indexes in plasma and liver. B-GOS effectively alleviated the OLZ-induced abnormal lipid metabolism by enhancing the diversity of the gut microbiota, with a 100-fold increase in Akkermansia abundance and a 10-fold decrease in Faecalibaculum abundance. Followed by the B-GOS related changes of gut microbiota, OLZ-induced substantial hepatic inhibition of PGRMC1, and associated protein factors of Wnt signaling pathway (Wnt3a, β-catenin, and PPAR-γ) were reversed without affecting plasma levels of short-chain fatty acids. Taken together, prebiotics like B-GOS enriching Akkermansia offer a promising novel approach to alleviate antipsychotic-induced lipid disturbances by modulating the PGRMC1-Wnt signaling pathway.

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

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. 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. 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 6days 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. 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.

Prenatal arsenite exposure alters maternal cardiac remodeling during late pregnancy

Exposure to inorganic arsenic through drinking water is widespread and has been linked to many chronic diseases, including cardiovascular disease. Arsenic exposure has been shown to alter hypertrophic signaling in the adult heart, as well as in utero offspring development. However, the effect of arsenic on maternal cardiac remodeling during pregnancy has not been studied. As such, there is a need to understand how environmental exposure contributes to adverse pregnancy-related cardiovascular events. This study seeks to understand the impact of trivalent inorganic arsenic exposure during gestation on maternal cardiac remodeling in late pregnancy, as well as offspring outcomes. C57BL/6 J mice were exposed to 0 (control), 100 or 1000 μg/L sodium arsenite (NaAsO2) beginning at embryonic day (E) 2.5 and continuing through E17.5. Maternal heart function and size were assessed via transthoracic echocardiography, gravimetric measurement, and histology. Transcript levels of hypertrophic markers were probed via qRT-PCR and confirmed by western blot. Offspring outcomes were assessed through echocardiography and gravimetric measurement. We found that maternal heart size was smaller and transcript levels of Esr1 (estrogen receptor alpha), Pgrmc1 (progesterone receptor membrane component 1) and Pgrmc2 (progesterone receptor membrane component 2) reduced during late pregnancy with exposure to 1000 μg/L iAs vs. non-exposed pregnant controls. Both 100 and 1000 μg/L iAs also reduced transcription of Nppa (atrial natriuretic peptide). Akt protein expression was also significantly reduced after 1000 μg/L iAs exposure in the maternal heart with no change in activating phosphorylation. This significant abrogation of maternal cardiac hypertrophy suggests that arsenic exposure during pregnancy can potentially contribute to cardiovascular disease. Taken together, our findings further underscore the importance of reducing arsenic exposure during pregnancy and indicate that more research is needed to assess the impact of arsenic and other environmental exposures on the maternal heart and adverse pregnancy events.

Computational Identification and Validation of Non-Synonymous SNPs in Progesterone Receptor Membrane Complex 1 Linked to Lung Cancer

Numerous gene polymorphisms have been attributed to Lung cancer, but PGRMC1 (Progesterone receptor membrane component 1) is a lesser-known candidate among them. However, emerging research is slowly suggesting the role of polymorphisms in PGRMC1 gene-associated tumorigenesis. Nevertheless, phenotypic changes still need to be studied. The main aim of this study is to identify the most deleterious nsSNPs (non-synonymous single nucleotide polymorphisms) in PGRMC1 that can potentially increase the susceptibility to lung cancer progression. In this work, we scrutinized highly detrimental nsSNPs for PGRMC1 from the available dbSNP database. We further categorized using the FATHMM server to enlist the nsSNPs, which are driver mutants capable of affecting the function of the PGRMC1 protein. We employed clinical evidence from the COSMIC database for further evaluation and confirming the presence of nsSNPs in lung cancer patients. There are 12 nsSNPs reported in lung cancer patients, which are L32M, R47C, D141N, G20W, S57C, R70P, I89V, G118V, A191D, G95V, E157K, and G168V predicted to damage the functions. Conclusively, through a comprehensive comparison of the outcomes obtained through these computational methods, we identified novel I89V, D120E, G95V and G168V nsSNPs that pose substantial risks to the functionality of the PGRMC1 protein. Focusing on the importance of PGRMC1 in lung cancer, analyzing its function was conceded to unveil the interlink between genetic mutation and phenotypic changes. Thus, this study provides insights into the influence of PGRMC1variants in Lung cancer. The evaluated nsSNPs can significantly aid future research on the gene and its association with lung cancer progression in large population distribution frequencies of genotypes among different subgroups.

Translocation of Adenosine A2B Receptor to Mitochondria Influences Cytochrome P450 2E1 Activity after Acetaminophen Overdose

The adenosine A2B receptor (A2BAR) is a member of a family of G-protein coupled receptors (GPCRs), which has a low affinity for adenosine and is now implicated in several pathophysiological conditions. We have demonstrated the beneficial effects of A2BAR activation in enhancing recovery after acute liver injury induced by an acetaminophen (APAP) overdose. While receptor trafficking within the cell is recognized to play a role in GPCR signaling, its role in the mediation of A2BAR effects in the context of APAP-induced liver injury is not well understood. This was investigated here, where C57BL/6J mice were subjected to an APAP overdose (300 mg/kg), and the temporal course of A2BAR intracellular localization was examined. The impact of A2BAR activation or inhibition on trafficking was examined by utilizing the A2BAR agonist BAY 60-6583 or antagonist PSB 603. The modulation of A2BAR trafficking via APAP-induced cell signaling was explored by using 4-methylpyrazole (4MP), an inhibitor of Cyp2E1 and JNK activation. Our results indicate that APAP overdose induced the translocation of A2BAR to mitochondria, which was prevented via 4MP treatment. Furthermore, we demonstrated that A2BAR is localized on the mitochondrial outer membrane and interacts with progesterone receptor membrane component 1 (PGRMC1). While the activation of A2BAR enhanced mitochondrial localization, its inhibition decreased PGRMC1 mitochondria levels and blunted mitochondrial Cyp2E1 activity. Thus, our data reveal a hitherto unrecognized consequence of A2BAR trafficking to mitochondria and its interaction with PGRMC1, which regulates mitochondrial Cyp2E1 activity and modulates APAP-induced liver injury.

Loss of progesterone receptor membrane component 1 decreases hepatic hepcidin levels in animal model

Loss of progesterone receptor membrane component 1 decreases hepatic hepcidin levels in animal model

Navigating a plethora of progesterone receptors: Comments on the safety/risk of progesterone supplementation in women with a history of breast cancer or at high-risk for developing breast cancer

Progesterone and progestin agonists are potent steroid hormones. There are at least three major types of progesterone receptor (PR) families that interact with and respond to progesterone or progestin ligands. These receptors include ligand-activated transcription factor isoforms (PR-A and PR-B) encoded by the PGR gene, often termed classical or nuclear progesterone receptor (nPR), membrane-spanning progesterone receptor membrane component proteins known as PGRMC1/2, and a large family of progestin/adipoQreceptors or PAQRs (also called membrane PRs or mPRs). Cross-talk between mPRs and nPRs has also been reported. The complexity of progesterone actions via a plethora of diverse receptors warrants careful consideration of the clinical applications of progesterone, which primarily include birth control formulations in young women and hormone replacement therapy following menopause. Herein, we focus on the benefits and risk of progesterone/progestin supplementation. We conclude that progesterone-only supplementation is considered safe for most reproductive-age women. However, women who currently have ER + breast cancer or have had such cancer in the past should not take sex hormones, including progesterone. Women at high-risk for developing breast or ovarian cancer, either due to their family history or known genetic factors (such as BRCA1/2 mutation) or hormonal conditions, should avoid exogenous sex hormones and proceed with caution when considering using natural hormones to mitigate menopausal symptoms and/or improve quality of life after menopause. These individuals are urged to consult with a qualified OB-GYN physician to thoroughly assess the risks and benefits of sex hormone supplementation. As new insights into the homeostatic roles and specificity of highly integrated rapid signaling and nPR actions are revealed, we are hopeful that the benefits of using progesterone use may be fully realized without an increased risk of women’s cancer.

Progesterone Receptor Membrane Component 1 (PGRMC1) Modulates Tumour Progression, the Immune Microenvironment and the Response to Therapy in Glioblastoma.

Progesterone Receptor Membrane Component 1 (PGRMC1) is a tumour-promoting factor in several types of cancer but its role in brain tumours is poorly characterized thus far. Our study aimed to determine the effect of PGRMC1 on glioblastoma (GBM) pathophysiology using two independent cohorts of IDH wild-type GBM patients and stable knockdown GBM models. We found that high levels of PGRMC1 significantly predicted poor overall survival in both cohorts of GBM patients. PGRMC1 promoted the proliferation, anchorage-independent growth, and invasion of GBM cells. We identified Integrin beta-1 (ITGB1) and TCF 1/7 as potential members of the PGRMC1 pathway in vitro. The levels of ITGB1 and PGRMC1 also correlated in neoplastic tissues from GBM patients. High expression of PGRMC1 rendered GBM cells less susceptible to the standard GBM chemotherapeutic agent temozolomide but more susceptible to the ferroptosis inducer erastin. Finally, PGRMC1 enhanced Interleukin-8 production in GBM cells and promoted the recruitment of neutrophils. The expression of PGRMC1 significantly correlated with the numbers of tumour-infiltrating neutrophils also in tissues from GBM patients. In conclusion, PGRMC1 enhances tumour-related inflammation and promotes the progression of GBM. However, PGRMC1 might be a promising target for novel therapeutic strategies using ferroptosis inducers in this type of cancer.

Progesterone receptor membrane component 1 facilitates Ca2+ signal amplification between endosomes and the endoplasmic reticulum

Membrane contact sites (MCSs) between endosomes and the endoplasmic reticulum (ER) are thought to act as specialized trigger zones for Ca2+ signaling, where local Ca2+ released via endolysosomal ion channels is amplified by ER Ca2+-sensitive Ca2+ channels into global Ca2+ signals. Such amplification is integral to the action of the second messenger, nicotinic acid adenine dinucleotide phosphate (NAADP). However, functional regulators of inter-organellar Ca2+ crosstalk between endosomes and the ER remain poorly defined. Here, we identify progesterone receptor membrane component 1 (PGRMC1), an ER transmembrane protein that undergoes a unique heme-dependent dimerization, as an interactor of the endosomal two pore channel, TPC1. NAADP-dependent Ca2+ signals were potentiated by PGRMC1 overexpression through enhanced functional coupling between endosomal and ER Ca2+ stores and inhibited upon PGRMC1 knockdown. Point mutants in PGMRC1 or pharmacological manipulations that reduced its interaction with TPC1 were without effect. PGRMC1 therefore serves as a TPC1 interactor that regulates ER-endosomal coupling with functional implications for cellular Ca2+ dynamics and potentially the distribution of heme.

Sigma Receptors: Novel Regulators of Iron/Heme Homeostasis and Ferroptosis.

Sigma receptors are non-opiate/non-phencyclidine receptors that bind progesterone and/or heme and also several unrelated xenobiotics/chemicals. They reside in the plasma membrane and in the membranes of the endoplasmic reticulum, mitochondria, and nucleus. Until recently, the biology/pharmacology of these proteins focused primarily on their role in neuronal functions in the brain/retina. However, there have been recent developments in the field with the discovery of unexpected roles for these proteins in iron/heme homeostasis. Sigma receptor 1 (S1R) regulates the oxidative stress-related transcription factor NRF2 and protects against ferroptosis, an iron-induced cell death process. Sigma receptor 2 (S2R), which is structurally unrelated to S1R, complexes with progesterone receptor membrane components PGRMC1 and PGRMC2. S2R, PGRMC1, and PGRMC2, either independently or as protein-protein complexes, elicit a multitude of effects with a profound influence on iron/heme homeostasis. This includes the regulation of the secretion of the iron-regulatory hormone hepcidin, the modulation of the activity of mitochondrial ferrochelatase, which catalyzes iron incorporation into protoporphyrin IX to form heme, chaperoning heme to specific hemoproteins thereby influencing their biological activity and stability, and protection against ferroptosis. Consequently, S1R, S2R, PGRMC1, and PGRMC2 potentiate disease progression in hemochromatosis and cancer. These new discoveries usher this intriguing group of non-traditional progesterone receptors into an unchartered territory in biology and medicine.

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.

Effects of estradiol, progesterone or cAMP on expression of PGRMC1 and progesterone receptor in a xenograft model of human endometrium and in endometrial cell culture

Estradiol and progesterone are key regulators of the menstrual cycle. In the human endometrium, progesterone induces morphological changes required for blastocyst implantation. Dysregulated response to progesterone can lead to endometrial pathologies including uterine bleeding and endometriosis. Besides the canonical nuclear progesterone receptor (encoded by the PGR gene), alternative response pathways include Progesterone Receptor Membrane Component 1 (PGRMC1), suspected to be involved in pathogenesis of endometrial diseases. We previously reported the spatiotemporal profile of PGRMC1 expression in the human endometrium along the menstrual cycle, highlighting progressive increase and decrease during the proliferative and secretory phases, respectively. Here we directly addressed its regulation by estradiol and progesterone, with systematic comparison with regulation of PGR expression. We found a direct correlation between expression of both genes during the proliferative and secretory phases in the cycling endometrium, but not during the menstrual phase. In a xenograft model mimicking the cycle phases, estradiol significantly increased and progesterone significantly decreased PGR expression but changes were not significant for PGRMC1. Finally, we did not find any significant effect of the ovarian steroids on expression of PGR or PGRMC1 in primary culture of endometrial stromal cells, except for a small increase in PGR expression by estradiol. Altogether, our experiments do not allow a major advance in our understanding of the mechanisms of cyclic variation of PGRMC1 expression, in particular regarding potential regulation by the ovarian steroids.

Embryo-maternal interactions revealed by phosphoproteomic analysis of endometrial organoids exposed to embryo secretome

The equine embryo remains mobile and without physical attachment to the endometrium for a prolonged period in early pregnancy. During this time, the embryo only communicates with the maternal system via secreted compounds in its immediate environment. These interactions are poorly understood, and a definitive signal for maternal recognition of pregnancy remains elusive. In this study, we sought to develop a model to examine embryo-maternal interactions at close range in vitro, demonstrating that incubation of endometrial organoids with embryo-conditioned medium results in detectable changes in the endometrial phosphoproteome. Mare endometrial organoids were derived from isolated endometrial glands of uteri obtained immediately post-mortem. Embryos were recovered by uterine lavage from Standardbred mares at day 8-9 post-ovulation, washed and pre-cultured in BSA-containing medium under oil, and cultured in protein-free medium under oil. Embryo-conditioned and control media were collected at 12 h, centrifuged to remove debris and stored at −80°C until further analysis. For co-incubation experiments, organoids were primed with 10nM estradiol (48 h), then 10nM estradiol + 1 µM progesterone (48 h). Embryo-conditioned (n=3) or control (n=3) media were added at a dilution of 1:100 in organoid medium and co-incubated for 30 minutes. Organoids were then recovered and processed to remove media and secretome components (on ice and in the presence of phosphatase inhibitors). Cell pellets were frozen at -80˚C until protein extraction. Proteins were extracted with urea-based extraction buffer, reduced,alkylated, and digested with trypsin. Phosphopeptides were isolated using titanium dioxide before LC tandem mass spectrometry (MS/MS) using a Q-Exactive Plus hybrid quadrupole-Orbitrap MS system (Thermo Fisher Scientific, Bremen, Germany). Endometrial organoids were successfully cultured in vitro and their functional mimicry of in vivo endometrium was confirmed via multiple routes including histological analysis of gland-like structures, epithelial and endometrial markers, and RNA sequencing alongside isolated endometrial glands. Phosphoproteomic mass spectrometry of endometrial organoids revealed a profile of 181 phosphopeptides mapping to 90 protein IDs. Of these, 10 phosphopeptides were decreased (log2[fold-change] < -0.8) in co-incubated organoids, while 3 were uniquely detected in secretome-exposed organoids only. Most notably, we observed a decrease in the phosphorylated peptides of PGRMC1 (progesterone receptor membrane component 1). This protein forms part of a non-classical system of progesterone action, located in the cell membrane. A change in PGRMC1 phosphorylation suggests that an alternative system of progesterone receptor activation participates in equine embryo-maternal signaling. There were also changes in phosphorylation status of chaperone proteins essential to progesterone receptor assembly (e.g., HSP90AB1). In summary, this study describes the immediate response of mare endometrial organoids to compounds released by embryos, identifying novel mechanisms possibly implicated in signaling between the embryo and maternal system.