Expression of progesterone receptor membrane component 1 and its partner serpine 1 mRNA binding protein in uterine and placental tissues of the mouse and human

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.

Altered luteal expression patterns of genomic and non-genomic progesterone receptors in bitches at different reproductive states

The binding of steroid hormones to their specific receptors is necessary to exert their effects on target cells. Progesterone (P4), a steroid hormone, carries out its effects through both genomic and non-genomic (the cell membrane-associated) receptors. This study aimed to ascertain luteal expression patterns of genomic and non-genomic progesterone receptors in bitches in physiological (early dioestrus and early pregnant) and pathological (pyometra) reproductive states. Luteal tissue was collected from the bitches at early dioestrus (ED, n = 5), early pregnant (EP, n = 5), and pyometra (PY, n = 5). The expression profiles of Steroidogenic Acute Regulator Protein (STAR), Progesterone Receptor (PGR), Membrane Progestin Receptors (PAQR5, PAQR7 and PAQR8), and Progesterone Membrane Components (PGMRC1 and PGMRC2) were examined at the mRNA levels using Real-Time Polymerase Chain Reaction (RT-PCR). Protein levels of PGR, PGMRC1 and PGMRC2 were detected by western blotting (WB). The STAR expression was found in all groups, with a statistical difference observed between EP and PY groups (P < 0.05). The protein level of PGR was determined to be highest in the EP group and lowest in the PY group. The expression of PAQR8 increased in the EP group (P < 0.05). The PAQR5 exhibited high expression in the EP group and low expression in the PY group (P < 0.05). PGRMC1 was more elevated in the EP group and lower in the PY group (P < 0.05). Protein levels of PGMRC1 and PGMRC2 were also observed at the highest expression in EP group. According to the altered expression profiles for examined receptors, we suggest that those progesterone receptors have roles in early pregnancy or pyometra in bitches.

Membrane-bound progesterone receptors in the canine uterus and placenta; possible targets in the maintenance of pregnancy

To date, the biological functions of P4 within the canine placenta have been attributed to maternal stroma-derived decidual cells as the only placental cells expressing the nuclear P4 receptor (PGR). However, P4 can also exert its effects via membrane-bound receptors. To test the hypothesis that membrane-bound P4 receptors are involved in regulating placental function in the dog, the expression of mPRα, -β, -γ, PGRMC1 and -2 was investigated in the uterine and placental compartments derived from different stages of pregnancy and from prepartum luteolysis. Further, to assess the PGR signaling-mediated effects upon membrane P4 receptors in canine decidual cells, in vitro decidualized dog uterine stromal (DUS) cells were treated with type II antigestagens (aglepristone or mifepristone). The expression of all membrane P4 receptors was detectable in reproductive tissues and in DUS cells. The main findings indicate their distinguishable placental spatio-temporal distribution; PGRMC2 was predominantly found in decidual cells, PGRMC1 was strong in maternal endothelial compartments, and syncytiotrophoblast showed abundant levels of mPRα and mPRβ. In vitro decidualization was associated with increased expression of PGRMC1 and -2, while their protein levels were diminished by antigestagen treatment. The involvement of membrane-bound P4 signaling in the regulation of canine placental function is implied, with P4 effects being directly exerted through maternal and fetal cellular compartments. The indirect effects of PGR might involve the modulation of membrane-bound receptors availability in decidual cells, implying a self-regulatory loop of P4 in regulating the availability of its own receptors in the canine placenta.

Heme induced progesterone-resistant profiling and promotion of endometriosis in vitro and in vivo

Endometriosis is an estrogen-dependent, progesterone-resistant gynecological disease with an unknown pathogenesis. Compared to women without endometriosis, women with endometriosis have a remarkably high heme level in the peritoneal fluid. To further investigate the pathomechanisms of heme in endometriosis, we aimed to identify the dysregulated expression of heme-trafficking proteins, such as PGRMC1/2 that are also receptors that mediate the non-genomic responses to progesterone, and heme-degrading enzymes between ectopic endometrial stromal cells and their normal counterparts. We found that heme could regulate progesterone receptor-related gene expression. Functional human endometrial stromal cell experiments showed that heme promotes cell proliferation and migration in a heme oxygenase-1-independent manner; moreover, blocking oxidative phosphorylation/ATP generation could abolish these effects of heme in vitro, whereas intraperitoneal hemopexin administration could alleviate heme-triggered ectopic lesions in vivo. Therefore, heme likely mediates the induction of progesterone resistance and simultaneously induces endometriosis via the mitochondrial oxidative phosphorylation pathway.

Role of progesterone on dexamethasone-induced alterations in placental vascularization and progesterone receptors in rats†

BACKGROUND

Intrauterine growth restriction (IUGR) is manifested by lower maternal progesterone levels, smaller placental size, and decreased placental vascularity indicated by lower expression of vascular endothelial growth factor (VEGF). Studies showed that progesterone increases angiogenesis and induces VEGF expression in different tissues. Therefore, the aim of the present study is to evaluate the effect of progesterone on placental vascular bed and VEGF expression and the modulation of nuclear and membranous progesterone receptors (PR) in dexamethasone-induced rat IUGR model.

METHODS

Pregnant Sprague-Dawley rats were allocated into four groups and given intraperitoneal injections of either saline, dexamethasone, dexamethasone, and progesterone or progesterone. Injections started on gestation day (DG) 15 and lasted until the days of euthanization (19 and 21 DG). Enzyme-linked immunosorbent assay was used to evaluate plasma progesterone levels. Real-time PCR and western blotting were used to evaluate gene and protein expressions of VEGF, and PR in labyrinth and basal placental zones. Immunohistochemistry was used to locate VEGF and different PRs in placental cells. Immunofluorescence was used to monitor the expression of blood vessel marker (αSMA).

RESULTS

Dexamethasone decreased the vascular bed fraction and the expression of VEGF in both placental zones. Progesterone co-treatment with dexamethasone prevented this reduction. Nuclear and membrane PRs showed tissue-specific expression in different placental zones and responded differently to both dexamethasone and progesterone.

CONCLUSIONS

Progesterone treatment improves the outcomes in IUGR pregnancy. Progesterone alleviated DEX-induced IUGR probably by promoting placental VEGF and angiogenesis.

Aberrant methylation of Serpine1 mediates lung injury in neonatal mice prenatally exposed to intrauterine inflammation

Background

Intrauterine inflammation (IUI) alters epigenetic modifications in offspring, leading to lung injury. However, the epigenetic mechanism underlying IUI-induced lung injury remains uncertain. In the present study, we aim to investigate the effect of IUI on lung development, and to identify the key molecule involved in this process and its epigenetic regulatory mechanism.

Results

Serpine1 was upregulated in the lung tissue of neonatal mice with IUI. Intranasal delivery of Serpine1 siRNA markedly reversed IUI-induced lung injury. Serpine1 overexpression substantially promoted cell senescence of both human and murine lung epithelial cells, reflected by decreased cell proliferation and increased senescence-associated β-galactosidase activity, G0/G1 cell fraction, senescence marker, and oxidative and DNA damage marker expression. IUI decreased the methylation level of the Serpine1 promoter, and methylation of the promoter led to transcriptional repression of Serpine1. Furthermore, IUI promoted the expression of Tet1 potentially through TNF-α, while Tet1 facilitated the demethylation of Serpine1 promoter. DNA pull-down and ChIP assays revealed that the Serpine1 promoter was regulated by Rela and Hdac2. DNA demethylation increased the recruitment of Rela to the Serpine1 promoter and induced the release of Hdac2.

Conclusion

Increased Serpine1 expression mediated by DNA demethylation causes lung injury in neonatal mice with IUI. Therefore, therapeutic interventions targeting Serpine1 may effectively prevent IUI-induced lung injury.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13578-022-00901-8.

The role of progesterone receptor membrane component (PGRMC) in the endometrium

PGRMC is a non-classical receptor that mediates the non-genomic responses to progesterone and is distributed in different subcellular compartments. PGRMC belongs to the membrane-associated progesterone receptor (MAPR) family. Two PGRMC subtypes (PGRMC1 and PGRMC2) have been characterized, and both are expressed in the human endometrium. PGRMC expression is differentially regulated during the menstrual cycle in the human endometrium. Although PGRMC1 is predominantly expressed in the proliferative phase and PGRMC2 in the secretory phase, this expression changes in pathologies such as endometriosis, in which PGRMC2 expression considerably decreases, promoting progesterone resistance. In endometrial cancer, PGRMC1 is overexpressed, its activation induces tumors growth, and confers chemoresistance in the presence of progesterone. Thus, PGRMCs play a key role in progesterone actions in the endometrium.

Pleiotropic Actions of PGRMC Proteins in Cancer

Progesterone receptor membrane component (PGRMC) proteins play important roles in tumor growth, progression, and chemoresistance, of which PGRMC1 is the best characterized. The ancestral member predates the evolution of metazoans, so it is perhaps not surprising that many of the purported actions of PGRMC proteins are rooted in fundamental metabolic processes such as proliferation, apoptosis, and DNA damage responses. Despite mediating some of the actions of progesterone (P4) and being fundamentally required for female fertility, PGRMC1 and PGRMC2 are broadly expressed in most tissues. As such, these proteins likely have both progesterone-dependent and progesterone-independent functions. It has been proposed that PGRMC1 acquired the ability to mediate P4 actions over evolutionary time through acquisition of its cytochrome b5-like heme/sterol-binding domain. Diverse reproductive and nonreproductive diseases associate with altered PGRMC1 expression, epigenetic regulation, or gene silencing mechanisms, some of which include polycystic ovarian disease, premature ovarian insufficiency, endometriosis, Alzheimer disease, and cancer. Although many studies have been completed using transformed cell lines in culture or in xenograft tumor approaches, recently developed transgenic model organisms are offering new insights in the physiological actions of PGRMC proteins, as well as pathophysiological and oncogenic consequences when PGRMC expression is altered. The purpose of this mini-review is to provide an overview of PGRMC proteins in cancer and to offer discussion of where this field must go to solidify PGRMC proteins as central contributors to the oncogenic process.

Chemerin Effect on the Endometrial Proteome of the Domestic Pig during Implantation Obtained by LC-MS/MS Analysis

Chemerin (CHEM) is a hormone mainly expressed in adipocytes involved in the regulation of energy homeostasis and inflammatory response. CHEM expression has been demonstrated in the structures of the porcine hypothalamic-pituitary-gonadal axis, as well as in the uterus, trophoblasts and conceptuses of pigs. In this study, we performed high-throughput proteomic analyses (liquid chromatography with tandem mass spectrometry, LC-MS/MS) to examine the influence of CHEM (400 ng/mL) on differentially regulated proteins (DRPs) in the porcine endometrial tissue explants during implantation (15 to 16 days of gestation). Among all 352 DRPs, 164 were up-regulated and 188 were down-regulated in CHEM-treated group. DRPs were assigned to 47 gene ontology (GO) terms (p-adjusted < 0.05). Validation of four DRPs (IFIT5, TGFβ1, ACO1 and PGRMC1) by Western blot analysis confirmed the veracity and accuracy of the LC-MS/MS method used in the present study. We suggest that CHEM, by modulating various protein expressions, takes part in the endometrial cell proliferation, migration and invasion at the time of implantation. It also regulates the endometrial immune response, sensitivity to P4 and the formation of new blood vessels. Additionally, CHEM appears to be an important factor involved in endothelial cell dysfunction during the pathogenesis of preeclampsia. The identification of a large number of DRPs under the influence of CHEM provides a valuable resource for understanding the molecular mechanisms of this hormone action during implantation, which is a prerequisite for better control of pig reproduction.

MicroRNAs and Progesterone Receptor Signaling in Endometriosis Pathophysiology

Endometriosis is a significant disease characterized by infertility and pelvic pain in which endometrial stromal and glandular tissue grow in ectopic locations. Altered responsiveness to progesterone is a contributing factor to endometriosis pathophysiology, but the precise mechanisms are poorly understood. Progesterone resistance influences both the eutopic and ectopic (endometriotic lesion) endometrium. An inability of the eutopic endometrium to properly respond to progesterone is believed to contribute to the infertility associated with the disease, while an altered responsiveness of endometriotic lesion tissue may contribute to the survival of the ectopic tissue and associated symptoms. Women with endometriosis express altered levels of several endometrial progesterone target genes which may be due to the abnormal expression and/or function of progesterone receptors and/or chaperone proteins, as well as inflammation, genetics, and epigenetics. MiRNAs are a class of epigenetic modulators proposed to play a role in endometriosis pathophysiology, including the modulation of progesterone signaling. In this paper, we summarize the role of progesterone receptors and progesterone signaling in endometriosis pathophysiology, review miRNAs, which are over-expressed in endometriosis tissues and fluids, and follow this with a discussion on the potential regulation of key progesterone signaling components by these miRNAs, concluding with suggestions for future research endeavors in this area.

Genome-Wide Association Study and Polygenic Risk Scores of Serum DHEAS Levels in a Chilean Children Cohort

CONTEXT

Adrenarche reflects the developmental growth of the adrenal zona reticularis, which produces increasing adrenal androgen secretion (eg, dehydroepiandrosterone [DHEA]/dehydroepiandrosterone sulfate [DHEAS]) from approximately age 5 to 15 years.

OBJECTIVE

We hypothesized that the study of the genetic determinants associated with variations in serum DHEAS during adrenarche might detect genetic variants influencing the rate or timing of this process.

METHODS

Genome-wide genotyping was performed in participants of the Chilean pediatric Growth and Obesity Chilean Cohort Study (GOCS) cohort (n = 788). We evaluated the genetic determinants of DHEAS levels at the genome-wide level and in targeted genes associated with steroidogenesis. To corroborate our findings, we evaluated a polygenic risk score (PRS) for age at pubarche, based on the discovered variants, in children from the same cohort.

RESULTS

We identified one significant variant at the genome-wide level in the full cohort, close to the GALR1 gene (P = 3.81 × 10-8). In addition, variants suggestive of association (P < 1 × 10-5) were observed in PRLR, PITX1, PTPRD, NR1H4, and BCL11B. Stratifying by sex, we found variants suggestive of association in SERBP1 and CAMTA1/VAMP3 for boys and near ZNF98, TRPC6, and SULT2A1 for girls. We also found significant reductions in age at pubarche in those children with higher PRS for greater DHEAS based on these newly identified variants.

CONCLUSION

Our results disclose one variant associated with DHEAS concentrations at the level of genome-wide association study significance, and several variants with a suggestive association that may be involved in the genetic regulation of adrenarche.

Effect of Steroid Hormones, Prostaglandins (E2 and F2α), Oxytocin, and Tumor Necrosis Factor Alpha on Membrane Progesterone (P4) Receptors Gene Expression in Bovine Myometrial Cells

Myometrium tissue shows the expression of non-genomic membrane progesterone (P4) receptors, such as progesterone receptor membrane components (PGRMC) 1 and 2 and membrane progestin receptors (mPR) alpha (mPRα), beta (mPRβ), and gamma (mPRγ). Their variable expression in the bovine uterus during the estrous cycle and early pregnancy suggests that ovarian steroids and luteotropic and/or luteolytic factors may regulate the expression of these receptors in the myometrium. Therefore, this study aimed to examine the effect of P4, estradiol (E2), P4 with E2, prostaglandins (PG) E2 and F2α, oxytocin (OT), and tumor necrosis factor α (TNFα) on the gene expression of PGRMC1, PGRMC2, serpine-1 mRNA-binding protein (SERBP1), and mPRα, mPRβ, and mPRγ in bovine myometrial cells from days 6 to 10 and 11 to 16 of the estrous cycle. The PGE2 concentration and mRNA expression were determined by EIA and real-time PCR, respectively. The data indicated that P4 and E2 can affect the mRNA expression of all studied receptors and SERPB1. However, PGE2, OT, and TNFα could only modulate the expression of PGRMC1, PGRMC2, and SERPB1, respectively. Steroids/factors changed the expression of PGRMC and mPR genes depending on the dose, the stage of the estrous cycle, and the types of receptors. This suggests that the local hormonal milieu may influence the activity of these receptors and P4 action in myometrial cells during the estrous cycle.

Progesterone Receptor Membrane Component (PGRMC)1 and PGRMC2 and Their Roles in Ovarian and Endometrial Cancer

Cancers of the female reproductive tract are both lethal and highly prevalent. For example, the five-year survival rate of women diagnosed with ovarian cancer is still less than 50%, and endometrial cancer is the fourth most common cancer in women with > 65,000 new cases in the United States in 2020. Among the many genes already established as key participants in ovarian and endometrial oncogenesis, progesterone receptor membrane component (PGRMC)1 and PGRMC2 have gained recent attention given that there is now solid correlative information supporting a role for at least PGRMC1 in enhancing tumor growth and chemoresistance. The expression of PGRMC1 is significantly increased in both ovarian and endometrial cancers, similar to that reported in other cancer types. Xenograft studies using human ovarian and endometrial cancer cell lines in immunocompromised mice demonstrate that reduced expression of PGRMC1 results in tumors that grow substantially slower. While the molecular underpinnings of PGRMCs' mechanisms of action are not clearly established, it is known that PGRMCs regulate survival pathways that attenuate stress-induced cell death. The objective of this review is to provide an overview of what is known about the roles that PGRMC1 and PGRMC2 play in ovarian and endometrial cancers, particularly as related to the mechanisms through which they regulate mitosis, apoptosis, chemoresistance, and cell migration.

The functional genetic architecture of egg-laying and live-bearing reproduction in common lizards

All amniotes reproduce either by egg-laying (oviparity), which is ancestral to vertebrates or by live-bearing (viviparity), which has evolved many times independently. However, the genetic basis of these parity modes has never been resolved and, consequently, its convergence across evolutionary scales is currently unknown. Here, we leveraged natural hybridizations between oviparous and viviparous common lizards (Zootoca vivipara) to describe the functional genes and genetic architecture of parity mode and its key traits, eggshell and gestation length, and compared our findings across vertebrates. In these lizards, parity trait genes were associated with progesterone-binding functions and enriched for tissue remodelling and immune system pathways. Viviparity involved more genes and complex gene networks than did oviparity. Angiogenesis, vascular endothelial growth and adrenoreceptor pathways were enriched in the viviparous female reproductive tissue, while pathways for transforming growth factor were enriched in the oviparous. Natural selection on these parity mode genes was evident genome-wide. Our comparison to seven independent origins of viviparity in mammals, squamates and fish showed that genes active in pregnancy were related to immunity, tissue remodelling and blood vessel generation. Therefore, our results suggest that pre-established regulatory networks are repeatedly recruited for viviparity and that these are shared at deep evolutionary scales.

What Do We Know about Classical and Non-Classical Progesterone Receptors in the Human Female Reproductive Tract? A Review

The progesterone hormone regulates the human menstrual cycle, pregnancy, and parturition by its action via the different progesterone receptors and signaling pathways in the female reproductive tract. Progesterone actions can be exerted through classical and non-classical receptors, or even a combination of both. The former are nuclear receptors whose activation leads to transcriptional activity regulation and thus in turn leads to slower but long-lasting responses. The latter are composed of progesterone receptors membrane components (PGRMC) and membrane progestin receptors (mPRs). These receptors rapidly activate the appropriate intracellular signal transduction pathways, and they can subsequently initiate specific cell responses or even modulate genomic cell responses. This review covers our current knowledge on the mechanisms of action and the relevance of classical and non-classical progesterone receptors in female reproductive tissues ranging from the ovary and uterus to the cervix, and it exposes their crucial role in female infertility.

Expression of nuclear progesterone receptor, progesterone receptor membrane components 1 and 2 and prostaglandin-endoperoxide synthase 2 in the endometrium and oviduct of spontaneously ovulating cats

Although ovulations not followed by pregnancy occur regularly in cats, differences in endometrial function between cats in the luteal and non-luteal phase have not been studied so far. Progesterone exerts its effects through a nuclear progesterone receptor (PGR) and via cell-membrane bound receptors referred to as progesterone receptor membrane component (PGRMC) 1 and 2. Progesterone receptor expression is regulated by gonadal steroid hormones and therefore may change throughout the oestrous cycle. Protein expression of PGR, PGRMC-1 and 2 and prostaglandin-endoperoxide synthase 2 (PTGS2) was analysed in the endometrium and oviduct of non-pregnant female cats in the follicular (n = 8) and luteal phase (n = 9). We hypothesized that the presence of corpora lutea (CL) is associated with downregulation of progesterone receptors and PTGS2. Cells of the luminal endometrial epithelium, endometrial stroma and oviductal epithelium were assessed by immunohistochemistry. The PGR protein expression was more pronounced in the endometrial epithelium than stroma (p < 0.001) and less pronounced in cats with a CL than without CL (p < 0.001) but did not differ between groups in the oviduct. The PTGS2 was localized only in the endometrial and oviductal epithelium and its expression was reduced in cats with CL (p = 0.001). In the endometrial epithelium, PGRMC-1 expression was reduced in cats with CL (p < 0.05). Expression of PGRMC-2 was highest in the endometrial epithelium and lowest in the endometrial stroma (p = 0.01) but did not differ between cats with and without CL. In conclusion, progesterone receptor and PTGS2 downregulation in the female cat closely resembles findings in other spontaneously ovulating domestic animal species.

Steroid hormone bioavailability is controlled by the lymphatic system

The steroid hormone progesterone accounts for immune tolerance in pregnancy. Enhanced progesterone metabolism to 6α-OH-pregnanolone occurs in complicated pregnancies such as in preeclampsia with preterm delivery or intrauterine growth restriction, and in cancer. As lymphatic endothelial cells (LECs) promote tumor immunity, we hypothesized that human LECs modify progesterone bioavailability. Primary human LECs and mice lymph nodes were incubated with progesterone and progesterone metabolism was analyzed by thin layer chromatography and liquid chromatography-mass spectrometry. Expression of steroidogenic enzymes, down-stream signal and steroid hormone receptors was assessed by Real-time PCR. The placental cell line HTR-8/SV neo was used as reference. The impact of the progesterone metabolites of interest was investigated on the immune system by fluorescence-activated cell sorting analysis. LECs metabolize progesterone to 6α-OH-pregnanolone and reactivate progesterone from a precursor. LECs highly express 17β-hydroxysteroid dehydrogenase 2 and are therefore antiandrogenic and antiestrogenic. LECs express several steroid hormone receptors and PIBF1. Progesterone and its metabolites reduced TNF-α and IFN-γ production in CD4+ and CD8+ T cells. LECs modify progesterone bioavailability and are a target of steroid hormones. Given the global area represented by LECs, they might have a critical immunomodulatory control in pregnancy and cancer.

Medroxyprogesterone opposes estradiol-induced renal damage in midlife ovariectomized Long Evans rats

OBJECTIVE

Our laboratory previously published that long-term administration of estradiol (E2) was detrimental to the kidneys of midlife ovariectomized Long Evans rats, contrasting clinical studies in showing that menopausal hormone therapy is associated with decreased albuminuria. However, it is unknown whether this renal benefit was due to estrogen and/or the combination with progestogen. Therefore, the objective of the current study was to determine the impact of medroxyprogesterone (MPA) on E2-mediated renal damage using a rodent model.

METHODS

Female Long Evans retired breeders underwent ovariectomy at 11 months of age and were treated for 40 days with subcutaneous E2, E2+MPA or vehicle at doses mimicking that of menopausal hormone therapy (N = 5-7 per group). Systolic blood pressure was measured along with indices of renal damage and function to investigate the impact of MPA on E2-mediated renal outcomes. Renal estrogen receptor alpha and G protein-coupled estrogen receptor transcript copy numbers were measured in all treatment groups through droplet digital PCR.

RESULTS

Middle-aged female Long Evans rats displayed spontaneous hypertension with similar systolic blood pressures and heart weights between groups. Even though blood pressure was comparable, E2 reduced glomerular filtration rate and increased proteinuria indicating pressure-independent renal damage. Coadministration with MPA prevented E2-induced glomerular filtration rate impairment and proteinuria by promoting renal hypertrophy and preventing renal interstitial fibrosis. Both E2 and E2+MPA reduced renal estrogen receptor alpha (ERα) and increased renal G protein-coupled estrogen receptor mRNA, but neither ERα nor ERß protein was different between groups.

CONCLUSION

MPA was protective against E2-induced renal damage and dysfunction in middle-aged female Long Evans rats. Assessing the impact of hormone therapy on renal outcomes may be an important clinical factor when considering treatment options for postmenopausal women.

miR-362-3p acts as a tumor suppressor by targeting SERBP1 in ovarian cancer

BACKGROUND

Ovarian cancer is the leading lethal gynecological cancer and is generally diagnosed during late-stage presentation. In addition, patients with ovarian cancer still face a low 5-year survival rate. Thus, innovative molecular targeting agents are required to overcome this disease. The present study aimed to explore the function of miR-362-3p and the underlying molecular mechanisms influencing ovarian cancer progression.

METHODS

The expression levels of miR-362-3p were determined using qRT-PCR. Gain-of-function and loss-of-function methods were used to detect the effects of miR-362-3p on cell proliferation, cell migration, and tumor metastasis in ovarian cancer. A luciferase reporter assay was performed to confirm the potential target of miR-362-3p, and a rescue experiment was employed to verify the effect of miR-362-3p on ovarian cancer by regulating its target gene.

RESULTS

miR-362-3p was significantly downregulated in ovarian cancer tissues and cell lines. In vitro, our data showed that miR-362-3p suppressed cell proliferation and migration. In vivo, miR-362-3p inhibited ovarian cancer growth and metastasis. Mechanistically, SERBP1 was identified as a direct target and functional effector of miR-362-3p in ovarian cancer. Moreover, SERBP1 overexpression rescued the biological function of miR-362-3p.

CONCLUSIONS

Our data reveal that miR-362-3p has an inhibitory effect on ovarian cancer. miR-362-3p inhibits the development and progression of ovarian cancer by directly binding its target gene SERBP1.

Effects of dibenzothiophene, a sulfur-containing heterocyclic aromatic hydrocarbon, and its alkylated congener, 2,4,7-trimethyldibenzothiophene, on placental trophoblast cell function

Worldwide demand for petroleum products has resulted in increased oil and gas activities in many countries. Conventional and unconventional oil and gas extraction, production, and transport lead to increased levels of petroleum-derived polycyclic aromatic hydrocarbons (PAHs) in the environment. PAH exposure has profound effects on reproduction by affecting pathways involved in placental trophoblast cell function and impairing normal placental development and function-key contributors to reproductive success. However, other components found in petroleum and wastewaters from oil and gas extraction, including the sulfur-containing heterocyclic aromatic compounds such as dibenzothiophene (DBT) and its alkylated derivatives, may also impact reproductive success. The goal of this study was to examine the effect of exposure to DBT, a compound commonly detected in the environment, and one of its alkylated analogues, 2,4,7-trimethyldibenzothiophene (2,4,7-DBT), on steroidogenic and angiogenic pathways critical for mammalian development in placental trophoblast cells (HTR-8/SVneo cells). 2,4,7-DBT but not DBT increased estradiol output in association with increased tube-like formation (surrogate for angiogenesis). These changes in angiogenesis did not appear to be related to altered expression of the key placental angiogenic gene targets (ANGPTL4, VEGFA, and PGF). Neither compound showed a concentration related effect on progesterone synthesis or its receptor expression. Our results suggest that 2,4,7-DBT can disrupt key pathways important for placental trophoblast function and highlight the importance of determining the impact of exposure to both parent and alkylated compounds. Further, these data suggest that exposure to sulfur-containing heterocyclic aromatic compounds may lead to placental dysfunction and impact reproductive success at environmentally relevant levels.

Selective Progesterone Receptor Modulators-Mechanisms and Therapeutic Utility

Selective progesterone receptor modulators (SPRMs) are a new class of compounds developed to target the progesterone receptor (PR) with a mix of agonist and antagonist properties. These compounds have been introduced for the treatment of several gynecological conditions based on the critical role of progesterone in reproduction and reproductive tissues. In patients with uterine fibroids, mifepristone and ulipristal acetate have consistently demonstrated efficacy, and vilaprisan is currently under investigation, while studies of asoprisnil and telapristone were halted for safety concerns. Mifepristone demonstrated utility for the management of endometriosis, while data are limited regarding the efficacy of asoprisnil, ulipristal acetate, telapristone, and vilaprisan for this condition. Currently, none of the SPRMs have shown therapeutic success in treating endometrial cancer. Multiple SPRMs have been assessed for efficacy in treating PR-positive recurrent breast cancer, with in vivo studies suggesting a benefit of mifepristone, and multiple in vitro models suggesting the efficacy of ulipristal acetate and telapristone. Mifepristone, ulipristal acetate, vilaprisan, and asoprisnil effectively treated heavy menstrual bleeding (HBM) in patients with uterine fibroids, but limited data exist regarding the efficacy of SPRMs for HMB outside this context. A notable class effect of SPRMs are benign, PR modulator-associated endometrial changes (PAECs) due to the actions of the compounds on the endometrium. Both mifepristone and ulipristal acetate are effective for emergency contraception, and mifepristone was approved by the US Food and Drug Administration (FDA) in 2012 for the treatment of Cushing's syndrome due to its additional antiglucocorticoid effect. Based on current evidence, SPRMs show considerable promise for treatment of several gynecologic conditions.

Progesterone receptor membrane component 1 is required for mammary gland development†

The physiological functions of progesterone (P4) in female reproductive organs including the mammary glands are mediated via the progesterone receptor (PR), but not all P4 functions can be explained by PR-mediated signaling. Progesterone receptor membrane component 1 (PGRMC1), a potential mediator of P4 actions, plays an important role in the ovary and uterus in maintaining female fertility and pregnancy, but its function in mammary glands has not been elucidated. This study investigated the role of PGRMC1 in mouse mammary gland development. Unlike in the uterus, exogenous estrogen (E2) and/or P4 did not alter PGRMC1 expression in the mammary gland, and Pgrmc1-knockout (KO) mice displayed reduced ductal elongation and side branching in response to hormone treatment. During pregnancy, PGRMC1 was expressed within both the luminal and basal epithelium and gradually increased with gestation and decreased rapidly after parturition. Moreover, although lactogenic capacity was normal after parturition, Pgrmc1 KO resulted in defective mammary gland development from puberty until midpregnancy, while the expression of PR and its target genes was not significantly different between wild-type and Pgrmc1-KO mammary gland. These data suggest that PGRMC1 is essential for mammary gland development during puberty and pregnancy in a PR-independent manner.

Expression of nuclear progesterone receptors (nPRs), membrane progesterone receptors (mPRs) and progesterone receptor membrane components (PGRMCs) in the human endometrium after 6 months levonorgestrel low dose intrauterine therapy

The classical steroid receptors (nuclear receptors), including those for progesterone (nPRs), are thoroughly characterized. The knowledge about so-called non-genomic effects, which are mediated by extra-nuclear initiated signals, has increased immensely the last decades. In a previous clinical study of endometrial hyperplasia, we observed that the antiproliferative progestin effect persisted after 3 months treatment with levonorgestrel (LNG) intrauterine system (IUS) even with a complete downregulation of nPRs. This raised the question of what other mechanisms than signaling through nPRs could explain such an observation. In the present study, RT-qPCR was employed to characterize mRNA expression for nPRs, membrane progesterone receptors (mPRs) and progesterone receptor membrane components (PGRMCs) in women (n = 42) with endometrial hyperplasia that received intrauterine low dose LNG for 6 months. At the end of this period endometrial tissue showed that nPRs were virtually completely downregulated (≈ 10 % of baseline) whereas the levels of remaining mPRs, subtype-α, -β and -γ were 76 %, 59 % and 73 % of baseline, respectively. PGRMC1 was downregulated to 15 % of baseline, in contrast to PGRMC2, which was upregulated to about 30 % above baseline. We used human cancer cells from uterine cervix (C-4I cells) as control. Progesterone caused a concentration-dependent antiproliferative effect but in several and separate studies, we were unable to detect nPRs (immunocytochemistry) in the C-4I cells. The use of RT-qPCR showed that nPRs were undetectable in C-4I cells, in contrast to mPRs and PGRMCs with a distinct mRNA expression. The present study suggests that mPRs and/or PGRMCs preserve the antiproliferative effect of LNG in the human endometrium and are responsible for the concentration-dependent antiproliferative effect of progesterone in C-4I cells.

Impaired oocyte maturation and ovulation in membrane progestin receptor (mPR) knockouts in zebrafish

Accumulating evidence suggest that membrane progestin receptor α (mPRα) is the membrane receptor mediating nongenomic progestin signaling that induces oocyte maturation in teleost. However, the involvement of other members of mPR family in oocyte maturation is still unclear. In this study, we found impaired oocyte maturation in zebrafish lacking mPRα1, mPRα2, mPRβ, or mPRγ2. In contrast, no difference was observed in oocyte maturation in the single knockout of mPRγ1, mPRδ, or mPRε. To study possible redundant functions of different mPRs in oocyte maturation, we generated a zebrafish line lacking all seven kinds of mPRs (mprs^-/-). We found oocyte maturation was further impaired in mprs^-/-. In addition, oocyte ovulation delay was observed in mprs^-/- females, which was associated with low levels of nuclear progestin receptor (Pgr), a key regulator for ovulation. We also found reduced fertility in mprs^-/- female zebrafish. Furthermore, eggs spawned by mprs^-/- females were of poor quality.

Complex interactomes and post-translational modifications of the regulatory proteins HABP4 and SERBP1 suggest pleiotropic cellular functions

The 57 kDa antigen recognized by the Ki-1 antibody, is also known as intracellular hyaluronic acid binding protein 4 and shares 40.7% identity and 67.4% similarity with serpin mRNA binding protein 1, which is also named CGI-55, or plasminogen activator inhibitor type-1-RNA binding protein-1, indicating that they might be paralog proteins, possibly with similar or redundant functions in human cells. Through the identification of their protein interactomes, both regulatory proteins have been functionally implicated in transcriptional regulation, mRNA metabolism, specifically RNA splicing, the regulation of mRNA stability, especially, in the context of the progesterone hormone response, and the DNA damage response. Both proteins also show a complex pattern of post-translational modifications, involving Ser/Thr phosphorylation, mainly through protein kinase C, arginine methylation and SUMOylation, suggesting that their functions and locations are highly regulated. Furthermore, they show a highly dynamic cellular localization pattern with localizations in both the cytoplasm and nucleus as well as punctuated localizations in both granular cytoplasmic protein bodies, upon stress, and nuclear splicing speckles. Several reports in the literature show altered expressions of both regulatory proteins in a series of cancers as well as mutations in their genes that may contribute to tumorigenesis. This review highlights important aspects of the structure, interactome, post-translational modifications, sub-cellular localization and function of both regulatory proteins and further discusses their possible functions and their potential as tumor markers in different cancer settings.

Progesterone induced Warburg effect in HEK293 cells is associated with post-translational modifications and proteasomal degradation of progesterone receptor membrane component 1

Progesterone (P4) is a major steroid hormone that has important effects on metabolism. The progesterone receptor membrane component 1 (PGRMC1) is a non-canonical P4 binding protein. The biological functions affected by PGRMC1 include cholesterol/steroid biosynthesis and metabolism, iron homeostasis and heme trafficking, autophagy, regulation of cell cycle and proliferation, cell migration and invasion. PGRMC1 has been an attractive target for therapeutic intervention in cancer and neurodegenerative disorders due to its biological role in promoting cell survival. P4 has been used in a number of clinical applications and is considered neuroprotective. The involvement of PGRMC1 in P4-mediated regulation of cellular glucose metabolism is not well studied. PGRMC1 is a 21 kDa protein but complex post-translational modifications (PTMs) lead to the existence of several high molecular mass proteins whose molecular function, intracellular distribution, and physiological relevancies are not fully known. Therefore, in this study, P4-PGRMC1-mediated cellular glucose metabolism and PTMs of PGRMC1 were studied using wild-type and CRISPR/Cas9 mediated PGRMC1 knockout (KO) human embryonic kidney-derived (HEK293) cell lines. A 70 kDa (p70) and 100 kDa (p100) PGRMC1 proteins were identified that are predominantly associated with endoplasmic reticulum/mitochondria and nuclear fractions in the cells, respectively. Phosphorylation, acetylation, ubiquitination, and sumoylation of native PGRMC1 under serum starvation were identified which provided an explanation for the higher molecular masses. This study indicates that P4-PGRMC1 signaling caused a rapid increase in glycolysis in the presence of oxygen (aerobic glycolysis) and a corresponding decrease in cellular respiration, known as the Warburg effect. Further, it was demonstrated that the P4-induced increase in glycolysis is associated with rapid proteasomal degradation of the p70 and reduction of the nuclear p100 protein level. P4 treatment also caused significant alteration in the dynamics of PGRMC1 PTMs and its association with potential interacting proteins. Overall, this study provides a hitherto unknown aspect of P4-PGRMC1 mediated signaling that changes basic cellular metabolism in HEK293 cells.

Progesterone-Related Immune Modulation of Pregnancy and Labor

Pregnancy involves a complex interplay between maternal neuroendocrine and immunological systems in order to establish and sustain a growing fetus. It is thought that the uterus at pregnancy transitions from quiescent to laboring state in response to interactions between maternal and fetal systems at least partly via altered neuroendocrine signaling. Progesterone (P4) is a vital hormone in maternal reproductive tissues and immune cells during pregnancy. As such, P4 is widely used in clinical interventions to improve the chance of embryo implantation, as well as reduce the risk of miscarriage and premature labor. Here we review research to date that focus on the pathways through which P4 mediates its actions on both the maternal reproductive and immune system. We will dissect the role of P4 as a modulator of inflammation, both systemic and intrinsic to the uterus, during human pregnancy and labor.

Effect of the duration of estradiol priming prior to progesterone administration on endometrial gene expression in anestrous mares

Field data indicate that a longer period of estrus prior to ovulation correlates positively with fertility. To test the hypothesis that the duration of exposure to estrogens prior to progesterone dominance influences endometrial function, we used anestrous mares to simulate varying durations of estrus (3 groups of 5 mares): long (LE), short (SE), and no estrus (NE), as determined by the duration of estradiol priming prior to progesterone treatment: 7, 2 and 0 days for the LE, SE and NE, respectively. Endometrial biopsies were recovered 4 days after progesterone administration in all groups for real time quantitative reverse transcription PCR (RT-qPCR) and immunohistochemical analyses. A total of 17 genes believed to contribute to a "receptive endometrium" for embryo development and viability were evaluated by RT-qPCR. Of the genes evaluated, the expression of FGF-2 (fibroblast growth factor-2) decreased with increased length of preceding estrus, whereas P19 (uterocalin) expression was higher in the LE than in the SE or NE groups. In conclusion, a lower abundance of FGF-2 and higher abundance of uterocalin, a lipocalin protein known to play an important role in providing lipids to the embryo, could contribute to a more receptive endometrium in mares following a long estrus.

The immunology of the macaque placenta: A detailed analysis and critical comparison with the human placenta

The cynomolgus monkey is increasingly considered in toxicological research as the most appropriate model for humans due to the species' close physiological contiguity, including reproductive physiology. Here, literature on the cynomolgus monkey placenta is reviewed in regards to its similarity to the human placenta and particularly for its immunological role, which is not entirely mirrored in humans. Pertinent original data are included in this article. The cynomolgus monkey placenta is evaluated based on three aspects: first, morphological development; second, the spatial and temporal appearance of maternal and fetal immune cells and certain immune cell products of the innate and adaptive immune systems; and third, the expression of relevant immune tolerance-related molecules including the homologs of anti-human leucocyte antigen, indoleamine 2,3-dioxygenase, FAS/FAS-L, annexin II, and progesterone. Parameters relevant to the immunological role of the placenta are evaluated from the immunologically immature stage of gestational day (GD) 50 until more mature stages close to birth. Selected comparisons are drawn with human and other laboratory animal placentas. In conclusion, the cynomolgus monkey placenta has a high degree of morphological and physiological similarity to the human placenta. However, there are differences in the topographical distribution of cell types and immune tolerance-related molecules. Three basic features are recognized: (1) the immunological capacity of the placenta changes throughout the lifetime of the organ; (2) these immunological changes include multiple parameters such as morphological adaptations, cell type involvement, and changes in immune-relevant molecule expression; and (3) the immune systems of two genetically disparate individuals (mother and child) are functionally intertwined at the maternal-fetal interface.

Maternal N-Carbamylglutamate Supply during Early Pregnancy Enhanced Pregnancy Outcomes in Sows through Modulations of Targeted Genes and Metabolism Pathways

Reducing pregnancy loss is important for improving reproductive efficiency for both human and mammalian animals. Our previous study demonstrates that maternal N-carbamylglutamate (NCG) supply during early pregnancy enhances embryonic survival in gilts. However, whether maternal NCG supply improves the pregnancy outcomes is still not known. Here we found maternal NCG supply during early pregnancy in sows significantly increased the numbers of total piglets born alive per litter ( P < 0.05) and significantly changed the levels of metabolites in amniotic fluid and serum involved in metabolism of energy, lipid, and glutathione and immunological regulation. The expression of endometrial progesterone receptor membrane component 1 (PGRMC1) was significantly increased by NCG supplementation ( P < 0.05) as well as the expression of PGRMC1, endothelial nitric oxide synthesases (eNOS), and lamin A/C in fetuses and placentae ( P < 0.05). Among the NCG-associated amino acids, arginine and glutamine, markedly increased PGRMC1 and eNOS expression in porcine trophectoderm cells ( P < 0.05), whereas glutamate could stimulate the expression of vimentin and lamin A/C in porcine trophectoderm (pTr) cells ( P < 0.05) and proline stimulated lamin A/C expression ( P < 0.05). Collectively, these data reveal the mechanisms of NCG in reducing early embryo loss. These findings have important implications that NCG has great potential to improve pregnancy outcomes in human and mammalian animals.

Endometrial response to conceptus-derived estrogen and interleukin-1β at the time of implantation in pigs

The establishment of pregnancy is a complex process that requires a well-coordinated interaction between the implanting conceptus and the maternal uterus. In pigs, the conceptus undergoes dramatic morphological and functional changes at the time of implantation and introduces various factors, including estrogens and cytokines, interleukin-1β2 (IL1B2), interferon-γ (IFNG), and IFN-δ (IFND), into the uterine lumen. In response to ovarian steroid hormones and conceptus-derived factors, the uterine endometrium becomes receptive to the implanting conceptus by changing its expression of cell adhesion molecules, secretory activity, and immune response. Conceptus-derived estrogens act as a signal for maternal recognition of pregnancy by changing the direction of prostaglandin (PG) F_2α from the uterine vasculature to the uterine lumen. Estrogens also induce the expression of many endometrial genes, including genes related to growth factors, the synthesis and transport of PGs, and immunity. IL1B2, a pro-inflammatory cytokine, is produced by the elongating conceptus. The direct effect of IL1B2 on endometrial function is not fully understood. IL1B activates the expression of endometrial genes, including the genes involved in IL1B signaling and PG synthesis and transport. In addition, estrogen or IL1B stimulates endometrial expression of IFN signaling molecules, suggesting that estrogen and IL1B act cooperatively in priming the endometrial function of conceptus-produced IFNG and IFND that, in turn, modulate endometrial immune response during early pregnancy. This review addresses information about maternal-conceptus interactions with respect to endometrial gene expression in response to conceptus-derived factors, focusing on the roles of estrogen and IL1B during early pregnancy in pigs.

PGRMC1 localization and putative function in the nucleolus of bovine granulosa cells and oocytes

Progesterone receptor membrane component-1 (PGRMC1) is a highly conserved multifunctional protein that is found in numerous systems, including reproductive system. Interestingly, PGRMC1 is expressed at several intracellular locations, including the nucleolus. The aim of this study is to investigate the functional relationship between PGRMC1 and nucleolus. Immunofluorescence experiments confirmed PGRMC1's nucleolar localization in cultured bovine granulosa cells (bGC) and oocytes. Additional experiments conducted on bGC revealed that PGRMC1 co-localizes with nucleolin (NCL), a major nucleolar protein. Furthermore, small interfering RNA (RNAi)-mediated gene silencing experiments showed that when PGRMC1 expression was depleted, NCL translocated from the nucleolus to the nucleoplasm. Similarly, oxidative stress induced by hydrogen peroxide (H2O2) treatment, reduced PGRMC1 immunofluorescent signal in the nucleolus and increased NCL nucleoplasmic signal, when compared to non-treated cells. Although PGRMC1 influenced NCL localization, a direct interaction between these two proteins was not detected using in situ proximity ligation assay. This suggests the involvement of additional molecules in mediating the co-localization of PGRMC1 and nucleolin. Since nucleolin translocates into the nucleoplasm in response to various cellular stressors, PGRMC1's ability to regulate its localization within the nucleolus is likely an important component of mechanism by which cells response to stress. This concept is consistent with PGRMC1's well-described ability to promote ovarian cell survival and provides a rationale for future studies on PGRMC1, NCL and the molecular mechanism by which these two proteins protect against the adverse effect of cellular stressors, including oxidative stress.

ANP promotes proliferation and inhibits apoptosis of ovarian granulosa cells by NPRA/PGRMC1/EGFR complex and improves ovary functions of PCOS rats

Polycystic ovary syndrome (PCOS) is a complicated reproductive endocrine disease characterized by polycystic ovaries, hyperandrogenism and anovulation. It is one of the main causes of infertility. RU486 is an antagonist of progesterone receptor, and most commonly used as a contraceptive. However, whether RU486 is correlated with PCOS remains unclear. Atrial natriuretic peptide (ANP) is a small peptide with natriuretic and diuretic functions, and its availability to be used in PCOS treatment is unknown. Here, we showed that the serum ANP level was lower in PCOS patients than that in healthy women, and it was also decreased in the serum and ovarian tissues of RU486-induced PCOS rats compared with the control rats. We also found that RU486 inhibited the proliferation and promoted the apoptosis of human KGN ovarian granulosa cells by downregulating progesterone receptor membrane component 1 (PGRMC1). Meantime, ANP promoted the proliferation and inhibited the apoptosis of KGN cells through upregulating ANP receptor A (NPRA). The promotive effects of ANP on ovarian functions were mediated through the formation of an NPRA/PGRMC1/EGFR complex, which further activated MAPK/ERK signaling and transcription factor AP1. Moreover, ANP treatment reversed the PCOS symptoms, and improved the fertility of RU486-induced PCOS rats. Collectively, these findings highlight that RU486 is associated with the pathogenesis of PCOS, and ANP treatment may be a promising therapeutic option for PCOS.

Dynamic expression of PGRMC1 and SERBP1 in human endometrium: an implication in the human decidualization process

OBJECTIVE

To characterize PGRMC1 and SERBP1 in human endometrium and to investigate the putative role of PGRMC1 in endometrial decidualization.

DESIGN

The PGRMC1 and SERBP1 expression in human endometrium was determined throughout the menstrual cycle. We analyzed the colocalization of PGRMC1 and SERBP1. Then, endometrial stromal cells (ESCs) were isolated to investigate the functional effect of PGRMC1 overexpression on decidualization.

SETTING

IVI clinic.

PATIENT(S)

Endometrial biopsies were collected from fertile volunteers (n = 61) attending the clinic as ovum donors.

INTERVENTION(S)

Endometrial samples of 61 healthy fertile women.

MAIN OUTCOME MEASURE(S)

In vivo localization of PGRMC1 and SERBP1 was assessed by immunohistochemistry. The PGRMC1/SERBP1 colocalization was investigated in vitro and in vivo. Decidualization effect of PGRMC1 overexpression was evaluated in primary ESC cultures.

RESULT(S)

The PGRMC1 was detected in the endometrial stroma throughout the menstrual cycle, but decreased in the late secretory phase. The SERBP1 immunostaining was present in stroma and increased in the entire the menstrual cycle. The PGRMC1 and SERBP1 colocalized in the cytoplasmic fractions of nondecidualized and decidualized ESC. The PGRMC1 overexpression significantly inhibited in vitro decidualization.

CONCLUSION(S)

Our results suggest that classic P receptors (PRs) are not the only kind playing a role in the normal physiology of the endometrium. The human decidualization process could be altered by the overexpression or mislocalization of PGRMC1 in ESC.

Effect of pregnancy on endometrial expression of luteolytic pathway components in the mare

Endometrial oxytocin receptors (OXTR) and prostaglandin-endoperoxide synthase 2 (PTGS2) are central components of the luteolytic pathway in cyclic mares, and their suppression is thought to be critical to luteal maintenance during early pregnancy. We examined the effect of pregnancy on endometrial expression of potential regulators of prostaglandin (PG) F2α secretion in mares. Expression of the nuclear progesterone receptor and oestrogen receptor ERα was high during oestrus, and depressed when progesterone was elevated; the opposite applied to the membrane progesterone receptor. PTGS2 was upregulated on Day 14 of dioestrus, but not pregnancy. Although OXTR mRNA expression was not elevated on Day 14 of dioestrus, protein abundance was; this increase in OXTR protein was absent on Day 14 of pregnancy. Intriguingly, gene and protein expression for PTGS2 and OXTR increased markedly between Days 14 and 21 of pregnancy suggesting that, although initial avoidance of luteolysis during pregnancy involves their suppression, this is a transient measure that delays rather than abolishes luteolytic pathway generation. The only oxytocin-PGF2α feedback loop component downregulated on both Days 14 and 21 of pregnancy was the PGF2α receptor we propose that downregulation of the PGF2α receptor uncouples the oxytocin-PGF2α feedback loop, thereby preventing generation of the large PGF2α pulses required for luteolysis.

Conditional Ablation of Progesterone Receptor Membrane Component 2 Causes Female Premature Reproductive Senescence

The nonclassical progesterone receptors progesterone receptor membrane component (PGRMC) 1 and PGRMC2 have been implicated in regulating cell survival of endometrial and ovarian cells in vitro and are abundantly expressed in these cell types. The objective of this study was to determine if Pgrmc1 and Pgrmc2 are essential for normal female reproduction. To accomplish this objective, Pgrmc1 and/or Pgrmc2 floxed mice (Pgrmc2fl/fl and Pgrmc1/2fl/fl) were crossed with Pgr-cre mice, which resulted in the conditional ablation of Pgrmc1 and/or Pgrmc2 from female reproductive tissues (i.e.,Pgrmc2d/d and Pgrmc1/2d/d mice). A breeding trial revealed that conditional ablation of Pgrmc2 initially led to subfertility, with Pgrmc2d/d female mice producing 47% fewer pups/litter than Pgrmc2fl/fl mice (P = 0.001). Pgrmc2d/d mice subsequently underwent premature reproductive senescence by parities 2 to 5, producing 37.8% fewer litters overall during the trial compared with Pgrmc2fl/fl mice (P = 0.020). Similar results were observed with Pgrmc1/2d/d mice. Based on ovarian morphology and serum P4, the subfertility/infertility was not due to faulty ovulation or luteal insufficiency. Rather an analysis of midgestation implantation sites revealed that postimplantation embryonic death was the major cause of the subfertility/infertility. As with our previous report of Pgrmc1d/d mice, Pgrmc2d/d and Pgrmc1/2d/d mice developed endometrial cysts consistent with accelerated aging of this tissue. Given the timing of postimplantation embryonic demise, uterine decidualization may be disrupted in mice deficient in PGRMC2 or PGRMC1/2. Overall, this study revealed that Pgrmc1 and/or Pgrmc2 are required for the maintenance of uterine histoarchitecture and normal female reproductive lifespan.

Conditional Ablation of Progesterone Receptor Membrane Component 1 Results in Subfertility in the Female and Development of Endometrial Cysts

Progesterone (P4) is essential for female fertility. The objective of this study was to evaluate the functional requirement of the nonclassical P4 receptor (PGR), PGR membrane component 1, in regulating female fertility. To achieve this goal, the Pgrmc1 gene was floxed by insertion of loxP sites on each side of exon 2. Pgrmc1 floxed (Pgrmc1(fl/fl)) mice were crossed with Pgr(cre) or Amhr2(cre) mice to delete Pgrmc1 (Pgrmc1(d/d)) from the female reproductive tract. A 6-month breeding trial revealed that conditional ablation of Pgrmc1 with Pgr(cre/+) mice resulted in a 40% reduction (P = .0002) in the number of pups/litter. Neither the capacity to ovulate in response to gonadotropin treatment nor the expression of PGR and the estrogen receptor was altered in the uteri of Pgrmc1(d/d) mice compared with Pgrmc1(fl/fl) control mice. Although conditional ablation of Pgrmc1 from mesenchymal tissue using Amhr2(cre/+) mice did not reduce the number of pups/litter, the total number of litters born in the 6-month breeding trial was significantly decreased (P = .041). In addition to subfertility, conditional ablation of Pgrmc1 using either Amhr2(cre/+) or Pgr(cre/+) mice resulted in the development of endometrial cysts starting around 4 months of age. Interestingly, pregnancy attenuated the formation of these uterine cysts. These new findings demonstrate that PGR membrane component 1 plays an important role in female fertility and uterine tissue homeostasis.

The emerging role of progesterone receptor membrane component 1 (PGRMC1) in cancer biology

Progesterone receptor membrane component 1 (PGRMC1) is a multi-functional protein with a heme-binding moiety related to that of cytochrome b₅, which is a putative progesterone receptor. The recently solved PGRMC1 structure revealed that heme-binding involves coordination by a tyrosinate ion at Y113, and induces dimerization which is stabilized by hydrophobic stacking of heme on adjacent monomers. Dimerization is required for association with cytochrome P450 (cyP450) enzymes, which mediates chemoresistance to doxorubicin and may be responsible for PGRMC1's anti-apoptotic activity. Here we review the multiple attested involvement of PGRMC1 in diverse functions, including regulation of cytochrome P450, steroidogenesis, vesicle trafficking, progesterone signaling and mitotic spindle and cell cycle regulation. Its wide range of biological functions is attested to particularly by its emerging association with cancer and progesterone-responsive female reproductive tissues. PGRMC1 exhibits all the hallmarks of a higher order nexus signal integration hub protein. It appears capable of acting as a detector that integrates information from kinase/phosphatase pathways with heme and CO levels and probably redox status.

Expression of Progesterone Receptor Membrane Component 1 (PGRMC1), Progestin and AdipoQ Receptor 7 (PAQPR7), and Plasminogen Activator Inhibitor 1 RNA-Binding Protein (PAIRBP1) in Glioma Spheroids In Vitro

Objective. Some effects of progesterone on glioma cells can be explained through the slow, genomic mediated response via nuclear receptors; the other effects suggest potential role of a fast, nongenomic action mediated by membrane-associated progesterone receptors. Methods. The effects of progesterone treatment on the expression levels of progesterone receptor membrane component 1 (PGRMC1), plasminogen activator inhibitor 1 RNA-binding protein (PAIRBP1), and progestin and adipoQ receptor 7 (PAQR7) on both mRNA and protein levels were investigated in spheroids derived from human glioma cell lines U-87 MG and LN-229. Results. The only significant alteration at the transcript level was the decrease in PGRMC1 mRNA observed in LN-229 spheroids treated with 30 ng/mL of progesterone. No visible alterations at the protein levels were observed using immunohistochemical analysis. Stimulation of U-87 MG spheroids resulted in an increase of PGRMC1 but a decrease of PAIRBP1 protein. Double immunofluorescent detection of PGRMC1 and PAIRBP1 identified the two proteins to be partially colocalized in the cells. Western blot analysis revealed the expected bands for PGRMC1 and PAIRBP1, whereas two bands were detected for PAQR7. Conclusion. The progesterone action is supposed to be mediated via membrane-associated progesterone receptors as the nuclear progesterone receptor was absent in tested spheroids.

Expression and immunolocalization of membrane progesterone receptors in the bovine oviduct

The oviduct plays a crucial role in the transport and maturation of gametes and ensures suitable conditions for fertility and early embryo development. One regulator of oviduct function is progesterone (P4), which affects the cell by interacting with nuclear progesterone receptors (PGRs) and through nongenomic mechanisms, presumably involving membrane PGRs. The aim of this study was to evaluate the expression of messenger RNAS (mRNAs) and proteins for progesterone receptor membrane component (PGRMC) 1 and 2 and membrane progestin receptors (mPR) α, β, and γ and to use immunohistochemistry to demonstrate their cell-specific localization in the bovine oviduct. Oviducts ipsilateral and contralateral to the corpus luteum or to the dominant follicle were collected from cows on days 6 to 12 (midluteal stage) and 18 to 20 (follicular stage) of the estrous cycle and divided into 3 parts (infundibulum, ampulla, and isthmus). There were no differences (P > 0.05) in the PGRMC1, PGRMC2, mPRα, β, and γ mRNA expression between ipsi- and contralateral oviducts. However, the same parts of the oviduct collected during the different stages of the estrous cycle showed higher (P < 0.05) mRNA levels of PGRMC1, PGRMC2, and mPRα on days 18 to 20 than on days 6 to 12 of the estrous cycle. mPRα and mPRβ mRNA levels were higher (P < 0.05) in the infundibulum than in the isthmus, whereas PGRMC1 expression was higher (P < 0.05) in the infundibulum than in ampulla. Immunohistochemistry was used to detect PGRMC1, PGRMC2, PRα, β, and γ proteins in all parts of both oviducts from days 6 to 12 and 18 to 20 of the estrous cycle. There were no differences in the staining intensity and cellular localization of the studied proteins between the ipsi- and contralateral oviducts and between the studied stages of the estrous cycle. A strong positive reaction was observed in luminal cells, but this reaction was less evident in myocytes and stromal cells. All proteins were also localized to the endothelial cells of blood vessels. These results suggest that membrane progesterone receptors, may be involved in the regulation of oviduct motility, secretory function, and blood flow in this organ.

Progesterone receptor membrane component 1 promotes survival of human breast cancer cells and the growth of xenograft tumors

Triple negative breast cancers (TNBCs) are highly aggressive and grow in response to sex steroid hormones despite lacking expression of the classical estrogen (E2) and progesterone (P4) receptors. Since P4 receptor membrane component 1 (PGRMC1) is expressed in breast cancer tumors and is known to mediate P4-induced cell survival, this study was designed to determine the expression of PGRMC1 in TNBC tumors and the involvement of PGRMC1 in regulating proliferation and survival of TNBC cells in vitro and the growth of TNBC tumors in vivo. For the latter studies, the MDA-MB-231 (MDA) cell line derived from TNBC was used. These cells express PGRMC1 but lack expression of the classical P4 receptor. A lentiviral-based shRNA approach was used to generate a stably transfected PGRMC1-deplete MDA line for comparison to the PGRMC1-intact MDA line. The present studies demonstrate that PGRMC1: 1) is expressed in TNBC cells; 2) mediates the ability of P4 to suppress TNBC cell mitosis in vitro; 3) is required for P4 to reduce the apoptotic effects of doxorubicin in vitro; and 4) facilitates TNBC tumor formation and growth in vivo. Taken together, these findings indicate that PGRMC1 plays an important role in regulating the growth and survival of TNBC cells in vitro and ultimately in the formation and development of these tumors in vivo. Thus, PGRMC1 may be a therapeutic target for TNBCs.

Differences in progesterone concentrations and mRNA expressions of progesterone receptors in bovine endometrial tissue between the uterine horns ipsilateral and contralateral to the corpus luteum

Because the establishment of pregnancy begins at the uterine horn ipsilateral to the corpus luteum (ipsi-horn) in cattle, levels of progesterone (P4) and receptor expression in the endometrial tissue, which regulate the intrauterine environment for embryo development, may differ between the ipsi-horn and the uterine horn contralateral to corpus luteum (contra-horn). The aim of the present study was to determine the endometrial tissue P4 concentrations and nuclear progesterone receptor (PGR), progesterone receptor membrane component 1 (PGRMC1) and PGRMC2 mRNA expressions in the cranial and middle parts of the uterine horns during the luteal phase. The results showed higher endometrial tissue P4 concentrations in the cranial part of the ipsi-horn than in that of the contra-horn (P<0.01); however, no change in the endometrial tissue P4 concentrations was evident during the luteal phase. The PGR mRNA expression was higher during the early luteal phase (P<0.05), but no differences between the horns were evident. However, PGRMC1 mRNA expression during the early luteal phase was higher in the cranial part of the ipsi-horn than in that of the contra-horn (P<0.05). In the middle part, there were no changes in the endometrial tissue P4 concentrations and P4 receptor expressions during the luteal phase. In conclusion, the differences in dynamics of endometrial tissue P4 concentrations and P4 receptor expressions between the uterine horns ipsilateral and contralateral to the ovary containing a corpus luteum may cause differences in the intrauterine environment for both the ipsi- and contra-horns.

Changes in myometrial expression of progesterone receptor membrane components 1 and 2 are associated with human parturition at term

While the exact mechanism of human parturition remains unknown, functional progesterone withdrawal is believed to play a key regulatory role. Progesterone receptor membrane components 1 and 2 (PGRMC1, PGRMC2) are putative progesterone receptors and the aim of this project was to investigate their expression in human myometrium. Human term myometrium was obtained from the lower uterine segment incision in women undergoing elective (not-in-labour, NIL; n = 11) and emergency Caesarean sections (in-labour, IL; n = 10), following written consent. PGRMC1 and 2 expression was quantified using real-time reverse transcription polymerase chain reaction and western blot. Subcellular localisation was performed by immunohistochemistry and immunofluorescence. There was a significant decrease in PGRMC1 mRNA (P = 0.0317) and protein expression (P = 0.0151) in IL myometrium, compared with NIL myometrium. PGRMC2 mRNA expression (P = 0.0151) was also decreased in IL myometrium, compared with NIL myometrium. Immunostaining studies confirmed the presence of PGRMC1 and 2 in smooth-muscle cells. Expression was perinuclear in NIL myometrium and more generalised and cytoplasmic in IL myometrium. The decrease in PGRMC1 expression and the translocation away from a perinuclear location for both PGRMC1 and 2 could contribute to a functional progesterone withdrawal that may ultimately initiate parturition.

SERBP1 Is a Component of the Liver Receptor Homologue-1 Transcriptional Complex

Liver receptor homologue-1 (LRH1) is an orphan nuclear receptor that has been shown to play a role in the transcriptional regulation of pathways involved in cancer. Elucidating the components of the LRH1 transcriptional complex to better understand endogenous regulation of the receptor as well as its role in cancer remains a high priority. A sub-cellular enrichment strategy coupled with proteomic approaches was employed to identify putative LRH1 co-regulators. Nuclear fractionation protocol was essential for detection of LRH1 peptides by mass spectrometry (MS), with most peptides being observed in the insoluble fraction (receptor bound to DNA). SERBP1 and ILF3 were identified as LRH1 interacting partners by both Western blot and MS/MS analysis. Receptor knockdown by siRNA showed an increase in SERBP1 expression, while ILF3 expression was unchanged. In contrast, receptor overexpression decreased only SERBP1 mRNA levels. Consistent with these data, in a promoter:reporter assay, binding of LRH1 to the promoter region of SERBP1 resulted in a decrease in the expression level of the reporter gene, subsequently inhibiting transcription. Given the receptor's role in cancer progression, the study here elucidates additional transcriptional machinery involved in LRH1 signaling and potentially provides new targets for therapeutics development.

Cyclic decidualization of the human endometrium in reproductive health and failure

Decidualization denotes the transformation of endometrial stromal fibroblasts into specialized secretory decidual cells that provide a nutritive and immunoprivileged matrix essential for embryo implantation and placental development. In contrast to most mammals, decidualization of the human endometrium does not require embryo implantation. Instead, this process is driven by the postovulatory rise in progesterone levels and increasing local cAMP production. In response to falling progesterone levels, spontaneous decidualization causes menstrual shedding and cyclic regeneration of the endometrium. A growing body of evidence indicates that the shift from embryonic to maternal control of the decidual process represents a pivotal evolutionary adaptation to the challenge posed by invasive and chromosomally diverse human embryos. This concept is predicated on the ability of decidualizing stromal cells to respond to individual embryos in a manner that either promotes implantation and further development or facilitates early rejection. Furthermore, menstruation and cyclic regeneration involves stem cell recruitment and renders the endometrium intrinsically capable of adapting its decidual response to maximize reproductive success. Here we review the endocrine, paracrine, and autocrine cues that tightly govern this differentiation process. In response to activation of various signaling pathways and genome-wide chromatin remodeling, evolutionarily conserved transcriptional factors gain access to the decidua-specific regulatory circuitry. Once initiated, the decidual process is poised to transit through distinct phenotypic phases that underpin endometrial receptivity, embryo selection, and, ultimately, resolution of pregnancy. We discuss how disorders that subvert the programming, initiation, or progression of decidualization compromise reproductive health and predispose for pregnancy failure.

Progesterone receptor membrane component 1 deficiency attenuates growth while promoting chemosensitivity of human endometrial xenograft tumors

Endometrial cancer is the leading gynecologic cancer in women in the United States with 52,630 women predicted to be diagnosed with the disease in 2014. The objective of this study was to determine if progesterone (P4) receptor membrane component 1 (PGRMC1) influenced endometrial cancer cell viability in response to chemotherapy in vitro and in vivo. A lentiviral-based shRNA knockdown approach was used to generate stable PGRMC1-intact and PGRMC1-deplete Ishikawa endometrial cancer cell lines that also lacked expression of the classical progesterone receptor (PGR). Progesterone treatment inhibited mitosis of PGRMC1-intact, but not PGRMC1-deplete cells, suggesting that PGRMC1 mediates the anti-mitotic actions of P4. To test the hypothesis that PGRMC1 attenuates chemotherapy-induced apoptosis, PGRMC1-intact and PGRMC1-deplete cells were treated in vitro with vehicle, P4 (1 µM), doxorubicin (Dox, 2 µg/ml), or P4 + Dox for 48 h. Doxorubicin treatment of PGRMC1-intact cells resulted in a significant increase in cell death; however, co-treatment with P4 significantly attenuated Dox-induced cell death. This response to P4 was lost in PGRMC1-deplete cells. To extend these observations in vivo, a xenograft model was employed where PGRMC1-intact and PGRMC1-deplete endometrial tumors were generated following subcutaneous and intraperitoneal inoculation of immunocompromised NOD/SCID and nude mice, respectively. Tumors derived from PGRMC1-deplete cells grew slower than tumors from PGRMC1-intact cells. Mice harboring endometrial tumors were then given three treatments of vehicle (1:1 cremophor EL: ethanol + 0.9% saline) or chemotherapy [Paclitaxel (15 mg/kg, i.p.) followed after an interval of 30 minutes by CARBOplatin (50 mg/kg)] at five day intervals. In response to chemotherapy, tumor volume decreased approximately four-fold more in PGRMC1-deplete tumors when compared with PGRMC1-intact control tumors, suggesting that PGRMC1 promotes tumor cell viability during chemotherapeutic stress. In sum, these in vitro and in vivo findings demonstrate that PGRMC1 plays a prominent role in the growth and chemoresistance of human endometrial tumors.

Hyaluronic acid promotes the expression of progesterone receptor membrane component 1 via epigenetic silencing of miR-139-5p in human and rat granulosa cells

Primary ovarian insufficiency (POI) is a serious reproductive dysfunction in which the follicle pool is reduced and depleted. Abnormal apoptosis of ovarian granulosa cells (GCs) is believed to result in follicle loss. Progesterone receptor membrane component 1 (PGRMC1), which is critical for GC survival, was reported to be reduced in POI patients, but the mechanism is unknown. In the present study, we found that PGRMC1 expression was correlated with the level of hyaluronic acid (HA) in POI patients. HA up-regulated PGRMC1 expression in GCs via suppression of miR-139-5p, which was proven by Western blotting and luciferase reporter assays to target PGRMC1. Consistent with these findings, levels of miR-139-5p were significantly increased and presented an inverse correlation with PGRMC1 in POI patients. Noticeably, HA inhibited CD44-mediated miR-139-5p expression but had no effect on luciferase activity after insertion of miR-139 promoter into luciferase plasmid. Interestingly, miR-139-5p was significantly up-regulated in KGN cells (GC tumor cell line) by the histone deacetylase inhibitor trichostatin A, indicating that HA down-regulated miR-139-5p expression via histone deacetylation. Taken together, we report an unrecognized mechanism of HA in the promotion of PGRMC1 expression, suggesting that HA may be a potential molecule for the prevention and treatment of POI.