Human granulosa cells of poor ovarian responder patients display telomeres shortening.

OBJECTIVE: We aimed to compare the telomere length in granulosa cells of the young normal and poor ovarian responder patients and elderly patients undergoing ovarian stimulation for IVF. METHODS: The main outcome measures granulosa cells telomere Length in the 3 study groups of patients undergoing IVF treatment in our center. 1) young normal responder patients (< 35 years); 2) young (< 35 years) poor ovarian responder patients; and 3) Elderly patients (40-45 years). Granulosa cells were obtained at the time of oocyte retrieval. Granulosa cells telomere length was assessed by absolute human telomere length quantification qPCR Assay. RESULTS: The telomere length of the young normal responder was significantly longer as compared to young poor ovarian responder (15.5 vs 9.6 KB, p < 0.001) and the elderly patients (15.5 vs 10.66 KB, p < 0.002). No significant difference was observed in the telomere length between the young poor ovarian responder and the elderly patients. CONCLUSIONS: Granulosa cells telomere length of the young normal responder was found to be significantly longer than young poor ovarian responder or elderly patients, highlighting the role of telomere length as a predictor, or contributor to poor oocyte yield following IVF treatment.

ABCC4 is a PGE2 efflux transporter in the ovarian follicle: A mediator of ovulation and a potential non-hormonal contraceptive target.

The role of prostaglandins (PGs) in the ovulatory process is known. However, the role of the ATP binding cassette subfamily C member 4 (ABCC4), transmembrane PG carrier protein, in ovulation remains unknown. We report herein that ABCC4 expression is significantly upregulated in preovulatory human granulosa cells (GCs). We found that PGE2 efflux in cultured human GCs is mediated by ABCC4 thus regulating its extracellular concentration. The ABCC4 inhibitor probenecid demonstrated effective blocking of ovulation and affects key ovulatory genes in female mice in vivo. We postulate that the reduction in PGE2 efflux caused by the inhibition of ABCC4 activity in GCs decreases the extracellular concentration of PGE2 and its ovulatory effect. Treatment of female mice with low dose of probenecid as well as with the PTGS inhibitor indomethacin or Meloxicam synergistically blocks ovulation. These results support the hypothesis that ABCC4 has an important role in ovulation and might be a potential target for non-hormonal contraception, especially in combination with PGE2 synthesis inhibitors. These findings may fill the gap in understanding the role of ABCC4 in PGE2 signaling, enhance the understanding of ovulatory disorders, and facilitate the treatment and control of fertility.

The in-vitro effect of gonadotropins' type and combination on Granulosa cells gene expressions.

OBJECTIVE: Nowadays, different modes and timing of GnRH-agonist combined with hCG trigger, for final follicular maturation, have been described. While LH + FSH are the naturally occurring final follicular maturation trigger, hCG is commonly use during stimulated cycle, and recently the introduction of the Dual/Double trigger combines LH + FSH + hCG. In the present study we aim to investigate the messenger RNA (mRNA) expression of reproduction-related genes in human granulosa cells (GCs) exposed to the aforementioned different types and combinations of gonadotropins. MATERIAL AND METHODS: Mural GCs were obtained from follicular fluid aspirated during IVF protocol. GCs were seeded in culture for 4 days with daily medium exchange followed by administration of either hCG (1 U/ml); FSH (1 U/ml) and LH (8 U/ml); or hCG (1 U/ml) and FSH (1 U/ml) and LH (8 U/ml) for 16 h. mRNA was purified from harvested GCs and gene expression was quantitative by qPCR. MAIN OUTCOME MEASURES: The expression of genes related to steroidogenesis (StAR/ CYP19) and oocyte maturation (COX2/Amphiregulin) in cultured GCs. RESULTS: The Dual/Double trigger (LH + FSH + hCG) showed higher activation of steroidogenesis (StAR/CYP19) and maturation (COX2/Amphiregulin) as compared to the naturally occurring trigger (LH + FSH) and the hCG triggers. Moreover, while the naturally occurring trigger (LH + FSH) activated maturation significantly and more intensely than the hCG trigger, no in between group differences were observed with regards to steroidogenic related genes. CONCLUSIONS: Our findings are in agreement with clinical experience, demonstrating the superiority of the double/dual (LH + FSH + hCG) trigger over the naturally occurring and the hCG triggers.

ERK1b, a 46-kDa ERK isoform that is differentially regulated by MEK.

The extracellular signal-regulated kinases (ERK) 1 and 2 (ERK1/2) are members of the mitogen-activated protein kinase family. Using various stimulated rodent cells and kinase activation techniques, we identified a 46-kDa ERK. The kinetics of activation of this ERK isoform was similar to that of ERK1 and ERK2 under most but not all circumstances. We purified this isoform from rat cells followed by its cloning. The sequence of this isoform revealed that it is an alternatively spliced version of the 44-kDa ERK1 and therefore we termed it ERK1b. Interestingly, this isoform had a 26-amino acid insertion between residues 340 and 341 of ERK1, which results from Intron 7 insertion to the sequence. Examining the expression pattern, we found that ERK1b is detected mainly in rat and particularly in Ras-transformed Rat1 cells. In this cell line, ERK1b was more sensitive to extracellular stimulation than ERK1 and ERK2. Moreover, unlike ERK1 and ERK2, ERK1b had a very low binding affinity to MEK1. This low interaction led to nuclear localization of this isoform when expressed together with MEK1 under conditions in which ERK1 and ERK2 are retained in the cytoplasm. In addition, ERK1b was not coimmunoprecipitated with MEK1. We identified a new, 46-kDa ERK alternatively spliced isoform. Our results indicate that this isoform is the major one to respond to exogenous stimulation in Ras-transformed cells, probably due to its differential regulation by MAPK/ERK kinase and by phosphatases.

The effect of coronavirus disease 2019 immunity on frozen-thawed embryo transfer cycles outcome.

OBJECTIVE: To study the effect of patients' immunization after coronavirus disease 2019 (COVID-19) infection or messenger ribonucleic acid (mRNA) severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine on frozen-thawed embryo transfer (FET). DESIGN: Cohort retrospective study. SETTING: Tertiary university affiliated medical center. PATIENT(S): All consecutive patients undergoing FET cycles in our center. The study group (immune group) consisted of patients treated during the COVID-19 pandemic (between January 2021 and August 2021) who either recovered from COVID-19 infection or received the mRNA SARS-CoV-2 vaccine. The control groups consisted of patients treated during the COVID-19 pandemic (between January 2021 and August 2021) but were not infected or did not receive the mRNA SARS-CoV-2 vaccine (not-immune2021 group) and those treated between January 2019 and August 2019 (before the pandemic) (not-immune2019 group). INTERVENTION(S): Frozen-thawed embryo transfer cycles. MAIN OUTCOME MEASURE(S): Ongoing pregnancy rates and FET cycles' characteristics. Data on patient age and variables related to infertility treatment were collected from the patient records. RESULT(S): During the study periods, 428 patients underwent 672 FET cycles. The immune group consisted of 141 patients who underwent 264 FET cycles (44 in postinfection and 220 in postvaccination), whereas the not-immune2021 and not-immune2019 groups consisted of 93 and 194 patients undergoing 125 and 283 FET cycles, respectively. Patients' characteristics and the types of endometrial preparations were comparable between the study groups. The implantation rate and clinical and ongoing pregnancy rates per transfer were similar between the study groups (immune group, postinfection and postvaccination; not-immune2021 group; not-immune2019 group). CONCLUSION(S): Coronavirus disease 2019 infection or vaccination did not affect patients' performance or implantation in their subsequent FET cycle.

Does gonadotropin-releasing hormone agonist cause luteolysis by inducing apoptosis of the human granulosa-luteal cells?

OBJECTIVES: To evaluates the effect of different modes of final follicular maturation triggering on the degree of apoptosis of granulosa cells (GCs) and the potential effect on progesterone secretion. METHODS: Thirty patients undergoing controlled ovarian hyperstimulation for IVF who received hCG, GnRH agonist, or dual trigger for final follicular maturation were included in the study. Granulosa cells were obtained at the time of oocyte retrieval. The proportion of apoptotic cells was evaluated via TUNEL and immunohistochemistry. RESULTS: The proportion of apoptotic cells was significantly higher in the GnRH agonist-alone group compared to hCG-alone and the dual trigger groups (13.5 ± 1.5% vs. 7.8% ± 1.8 vs. 10.1% ± 2, respectively, P < 0.01). Moreover, the expression of active-caspase-3 was also significantly increased in the GnRH agonist-alone group compared with the hCG-alone and the dual trigger groups (15.5% ± 2.9 vs. 8.4% ± 1.6 vs. 12.7% ± 2.6, respectively, P < 0.01). The progesterone levels measured in the granulosa-luteal cell culture medium after 24 h of incubation were similar between the three groups. CONCLUSIONS: The levels of apoptosis are increased after GnRH agonist/dual trigger. The increased apoptosis might be one of the culprit of the subsequent premature demise of the corpus luteum post GnRH agonist trigger.

NF-κB-miR-155 axis activation mediates ovulation-induced oncogenic effects in fallopian tube epithelium.

The fallopian tube secretory epithelial cells (FTSECs) are the cell-of-origin of most high-grade serous ovarian carcinomas (HGSOC). FTSECs are repeatedly exposed to inflammation induced by follicular fluid (FF) that is released with every ovulation cycle throughout a woman's reproductive years. Uninterrupted ovulation cycles are an established risk factor for HGSOC. Stimuli present in the FF induce an inflammatory environment which may cause DNA damage eventually leading to serous tumorigenesis. With the aim of elucidating possible mechanistic pathways, we established an 'ex vivo persistent ovulation model' mimicking the repeated exposure of human benign fallopian tube epithelium (FTE) to FF. We performed mass spectrometry analysis of the secretome of the ex vivo cultures as well as confirmatory targeted expressional and functional analyses. We demonstrated activation of the NF-κB pathway and upregulation of miR-155 following short-term exposure of FTE to human FF. Increased expression of miR-155 was also detected in primary HGSOC tumors compared with benign primary human FTE and corresponded with changes in the expression of miR-155 target genes. The phenotype of miR-155 overexpression in FTSEC cell line is of increased migratory and altered adhesion capacities. Overall, activation of the NF-κB-miR-155 axis in FTE may represent a possible link between ovulation-induced inflammation, DNA damage, and transcriptional changes that may eventually lead to serious carcinogenesis.

Can we predict oocyte maturation prior to denudation for intracytoplasmic sperm injection?

Intracytoplasmic sperm injection (ICSI) was introduced in 1992 as a method to treat couples with severe male infertility. However, in the last two decades, the use of ICSI has increased substantially even among patients without male factor infertility. In ICSI the oocytes are scrutinized for maturity upon insemination and the immature oocytes are discarded. The aim of the present study was to assess the ability of an experienced embryologist to identify the maturity of the oocytes prior to their denudation.In the present prospective observational study, four experienced embryologists examined the oocytes prior to their denudation and decided whether the oocytes were mature or immature. Later, the oocytes were denudated and the embryologist again examined the oocytes to confirm their prior assumptions.483 oocytes were examined by four embryologists. Three hundred and fifty one of the oocytes were mature (72.7%) and 132 were immature (27.3%). The embryologists were able to correctly identify oocytes maturation status in 85.3% of cases. The embryologists were able to correctly identify 90% of the mature oocytes and 72.7% of the immature oocytes. When they assumed that the oocytes were mature they were correct in 89.% of the cases, while only 74.6% of their prediction that the oocytes were immature were true. To conclude, the embryologists are able to identify the oocytes maturation status before denudation at the majority of the cases. Whenever the oocytes are suspected to be immature, further consideration should be made whether to proceed to ICSI or not.

HAS2-AS1 is a novel LH/hCG target gene regulating HAS2 expression and enhancing cumulus cells migration.

BACKGROUND: The cumulus expansion process is one of the LH mediated ovulatory processes. Hyaluronan synthase 2 (HAS2) regulates the synthesis of hyaluronic acid, the main component of the cumulus expansion process. Recently, the lncRNA HAS2 antisense RNA 1 (HAS2-AS1) was identified in our global transcriptome RNA-sequencing of novel ovulation associated genes. The role of HAS2-AS1 in HAS2 regulation w.as studied previously with contradictive results in different models but not in the ovary. Taken together the induction of HAS2-AS1 and the important role of HAS2 in the cumulus expansion process, we hypothesize that HAS2-AS1 regulate HAS2 expression and function in the ovary. Therefore we undertook to study the expression, regulation, and possible functional role of HAS2-AS1 in the human ovary. RESULTS: HAS2-AS1, located within the HAS2 gene that was highly regulated in our library. We found that HAS2-AS1 express mainly in cumulus cells (CCs). Furthermore, HAS2-AS1 showed low expression in immature CCs and a significant increase expression in mature CCs. Functional studies reveal that inhibition of HAS2-AS1 by siRNA caused decrease expression of HAS2. Furthermore, inhibition of HAS2-AS1 by siRNA results in decrease migration of granulosa cells. CONCLUSIONS: Our results suggest that HAS2-AS1 is an LH/hCG target gene that plays a positive role in HAS2 expression and thus might play a role in regulating cumulus expansion and migration.

An optimized model for hCG stimulation of human mural granulosa cell culture.

Ovarian follicular development and ovulation in mammals is a highly-regulated process. Most of the current knowledge of ovarian processes was obtained from the studies of non-human models. Molecular studies on human ovarian processes suffer from lack of material and appropriate research tools. Mural granulosa cells (MGCs) culture is a major tool for studying the effect of different substances but a major problem for using these primary MGCs is their unresponsiveness to hCG stimulation at the time of oocyte retrieval. It is acceptable that MGCs regain responsiveness during days in culture but when the best time is and how to accelerate the regenerative process are unknown. The aim of the current study was to establish an optimized protocol which will provide a practical and efficient tool to examine the effect of LH/hCG on different downstream targets in luteinized MGCs. hCG effects were examined according to days in culture and hCG stimulation time. As read-out, we analyzed the gene expression of known hCG targets, protein production, and progesterone secretion. Our results show that with a daily medium exchange, the strongest effect was achieved already 4 days after seeding. On day 4, hCG stimulation triggers two major patterns of gene expression. Early induced genes were highly expressed 6-8 h after hCG, while 24 h of hCG stimulation was needed for late induced genes. Based on our results, we suggest daily medium exchange for 4 days before adding hCG and examine its effect 6 and 24 h later.

Differential regulation of cumulus cell transcription during oocyte maturation in vivo and in vitro.

Differences in cumulus cell gene expression after oocyte maturation in vitro (IVM) or in vivo have been described in previous studies. However, the possible impact of follicle stage on gene expression deregulation during human oocyte IVM remains unknown. Expression of selected genes of interest was compared in cumulus cell of three classes of human cumulus cell-oocyte complexes (COCs): a) COCs derived from human chorionic gonadotropin (hCG)-triggered IVM cycles, collected at the germinal vesicle (GV) stage from mid-sized follicles (4-12 mm) and matured in vitro (IVM-GV); b) COCs derived from hCG-triggered IVM cycles, collected from mid-sized follicles (4-12 mm) and matured in vivo (IVM-MII); c) COCs derived from controlled ovarian stimulation in vitro fertilization (IVF) cycles, collected from large/preovulatory follicles and matured in vivo (IVF-MII). Overall, mRNA levels of the large majority of the 20 genes of different regulative and metabolic pathways subject to analysis were altered in IVM samples compared with in vivo matured COCs. In some cases, follicle size appeared to have a role in determining transcription deregulation. For example, in comparison to the IVF-MII control, the luteinizing hormone receptor was largely overexpressed in both IVM-GV and IVM-MII COCs, therefore irrespective of IVM. However, in other circumstances follicle size and IVM had distinct and opposite impacts on gene expression, as shown by transcription of amphiregulin, which was increased in IVM-MII COCs, but decreased in COCs matured in vitro (IVM-GV) compared with the IVF-MII control. This study confirms and extends previous data on gene expression dysregulation during IVM and indicates that the size of follicles from which immature oocytes are retrieved can be an independent factor of differential transcriptional regulation.

Standard human chorionic gonadotropin versus double trigger for final oocyte maturation results in different granulosa cells gene expressions: a pilot study.

OBJECTIVE: To investigate the messenger RNA (mRNA) expression of reproduction-related genes in granulosa cells (GCs) of patients triggered with hCG compared with patients triggered with GnRH agonist and hCG (double trigger) for final oocyte maturation. DESIGN: Granulosa cells were obtained at the time of oocyte retrieval, and gene expression was analyzed using quantitative real-time polymerase chain reaction. SETTING: Referral center. PATIENT(S): Fifteen women undergoing controlled ovarian hyperstimulation for IVF who received hCG for final follicular maturation and in a subsequent IVF cycle received double trigger. INTERVENTION(S): Granulosa cells collection. MAIN OUTCOME MEASURE(S): The expression of genes related to ovarian hyperstimulation syndrome, gap junction, and epidermal-like growth factor in GCs. RESULT(S): The mRNA expressions of amphiregulin (2.1 vs. 1, arbitrary unit) and epiregulin (2.5 vs. 1, arbitrary unit) were significantly higher in the double trigger group compared with the hCG group. We found no difference in luteinizing hormone receptor and follicle stimulating hormone receptor mRNA expressions between the two groups. Moreover, although the mRNA expression of pigment epithelium-derived factor (1.5 vs. 1, arbitrary unit) was significantly higher in the double trigger group, no between-group differences were observed in the expression of vascular endothelial growth factor and GnRH receptor. The mRNA expression of conexin43 in cumulus cells (0.7 vs. 1, arbitrary unit) was significantly lower in the double trigger group compared with the hCG group. CONCLUSION(S): Our findings suggest that the decreased expression of conexin43 and the increased expression of epiregulin and amphiregulin in the GCs from patients receiving the double trigger may explain the suggested improved oocyte and embryo quality related to the double triggering group.

The prostaglandin transporter (PGT) as a potential mediator of ovulation.

Prostaglandins (PGs) play an important role in the ovulatory process. However, the role of the PG transporter (PGT) in this context remains unknown. We report that the expression of PGT, a transmembrane PG carrier protein, is markedly up-regulated in preovulatory human granulosa cells (GCs). Treatment with human chorionic gonadotropin (hCG), an ovulatory trigger, significantly increases the expression of PGT mRNA and protein in human GCs both in vivo and in vitro. The hCG-induced increase in the expression of PGT in cultured human GCs is mediated via protein kinase A and protein kinase C by way of the extracellular signal-regulated kinase pathway. PGT in cultured human GCs mediates the uptake of PGE2, thereby regulating its extracellular concentration. In vivo treatment of mice with PGT inhibitors effectively blocks ovulation and markedly attenuates the expression of key ovulatory genes. We hypothesize that the inhibition of PGT activity in GCs increases the extracellular concentration of PGE2, the ability of which to exert its ovulatory effect is compromised by desensitization of its cognate receptors. Together, these findings support the idea that PGT is an important mediator of ovulation and that its inhibitors may be viewed as potential candidates for nonhormonal contraception. These findings may also fill the gap in the understanding of PGT signaling, enhance the understanding of ovulatory disorders, and facilitate the treatment of infertility or subfertility in women by using nonsteroidal PG-based therapeutic approaches.

Does BPA alter steroid hormone synthesis in human granulosa cells in vitro?

STUDY QUESTION: Does Bisphenol A (BPA) impair steroid hormone production in human luteinized granulosa cells in vitro? SUMMARY ANSWER: At supra-physiological concentrations, BPA alters progesterone and estradiol synthesis in vitro and significantly reduces the mRNA and protein expression levels of three genes encoding steroidogenesis enzymes. WHAT IS KNOWN ALREADY: In IVF patients, the effects of BPA exposure on cycle outcome are controversial. Previous animal studies have shown that granulosa cell steroid hormone synthesis is compromised after BPA exposure, but their findings have been difficult to replicate in humans due, in part, to the low availability of discarded biological material. STUDY DESIGN, SIZE, DURATION: Luteinized granulosa cells obtained from 44 fertile and infertile patients undergoing in vitro fertilization were cultured for 48 h with different concentrations of BPA (0, 0.2, 0.02, 2.0, 20 µg/ml). PARTICIPANTS/MATERIALS, SETTING, METHODS: Culture medium and total RNA extracted from the luteinized granulosa cells were examined for estradiol and progesterone levels as well as mRNA and protein expression of steroidogenesis enzymes, using enzyme immunoassays, real-time PCR and western blots. MAIN RESULTS AND THE ROLE OF CHANCE: Treatment of granulosa cells with 2 or 20 µg/ml BPA for 48 h resulted in significantly lower progesterone biosynthesis (P < 0.005 and <0.001, respectively). Estradiol production was significantly altered only after incubation with 20 µg/ml of BPA (P < 0.001). These concentrations also significantly reduced the mRNA levels of 3ß-hydroxysteroid dehydrogenase (3ß-HSD), CYP11A1 and CYP19A1 without affecting StAR and 17ß-hydroxysteroid dehydrogenase mRNA expression. Similarly, 3ß-HSD, CYP11A1 and CYP19A1 protein levels were reduced after administration of 20 µg/ml BPA. Lower BPA concentrations similar to, and up to 100 times, the concentrations measured in human follicular fluid, serum and urine did not alter steroidogenesis in primary granulosa cell cultures. LIMITATIONS, REASONS FOR CAUTION: This was an in vitro study investigating the effects of acute exposure (48 h) of BPA on discarded material. As such, the model may not accurately reflect the effect of BPA on the physiological events of follicular steroid hormone synthesis in vivo. WIDER IMPLICATIONS OF THE FINDINGS: Our results show that in vitro exposure to BPA at low doses does not affect granulosa cells steroidogenesis. Combined with recent in vivo studies, these data can be reassuring but further studies are needed to assess the effects of chronic exposure to BPA on ovarian steroidogenesis. STUDY FUNDING AND COMPETING INTERESTS: This study was supported by grant number 1936/12 from the Israeli Science Foundation (ISF). The authors have no conflict of interest.

Activation-Induced Cytidine Deaminase Links Ovulation-Induced Inflammation and Serous Carcinogenesis.

In recent years, the notion that ovarian carcinoma results from ovulation-induced inflammation of the fallopian tube epithelial cells (FTECs) has gained evidence. However, the mechanistic pathway for this process has not been revealed yet. In the current study, we propose the mutator protein activation-induced cytidine deaminase (AID) as a link between ovulation-induced inflammation in FTECs and genotoxic damage leading to ovarian carcinogenesis. We show that AID, previously shown to be functional only in B lymphocytes, is expressed in FTECs under physiological conditions, and is induced in vitro upon ovulatory-like stimulation and in vivo in carcinoma-associated FTECs. We also report that AID activity results in epigenetic, genetic and genomic damage in FTECs. Overall, our data provides new insights into the etiology of ovarian carcinogenesis and may set the ground for innovative approaches aimed at prevention and early detection.

Anti Müllerian Hormone (AMH) level and expression in mural and cumulus cells in relation to age.

BACKGROUND: Serum AMH is declining with age and is highly associated with ovarian follicular reserve and disordered folliculogenesis. However, the precise role of AMH in the process of human follicular aging has still to be determined. AIM: This study investigates AMH level in the follicular fluid (FF) and mRNA expression pattern in cumulus and mural granulosa cells of human ovarian follicles in relation to age. METHODS: We conducted a prospective study. Sixty-eight women undergoing In vitro fertilization (IVF) treatment were enrolled in the study. We obtained FF, mural and cumulus granulosa cells from large preovulatory follicles (17-20 mm) of 21-35 years old women (n = 40) and 40-45 years old women (n = 28) during oocyte pickup. RESULTS: Higher level of AMH mRNA expression in cumulus cells was observed in the older age group compared to the younger (P <0.01). In accordance with AMH mRNA expression results, FF AMH protein levels were significantly higher in the older group than in the younger group (4.7 ± 1.1 ng\ml and 2.3 ± 0.2 ng\ml respectively, p < 0.002). CONCLUSIONS: AMH is highly expressed and secreted from cumulus GCs of advanced age patients. This remarkable correlation between AMH mRNA levels in cumulus cells in respect to age suggests that AMH may be involved in follicular aging process.

Differential expression of poliovirus receptor, regulator of G-protein signaling 11 and erythrocyte protein band 4.1-like 3 in human granulosa cells during follicular growth and maturation.

Poliovirus receptor (PVR), regulator of G-protein signaling-11 (RGS11), and erythrocyte protein band-4.1-like 3 (EPB41L3) have been proposed to function in follicular maturation in mouse models. We have examined their expression in human mural (mGCs) and cumulus granulosa cells (CCs). Expression of PVR and RGS11 in mGCs decreased in medium-sized follicles compared to small follicles of IVM cycles and increased again in large follicles. Luteinization caused decreased expression of both PVR and RGS11. In vitro incubation of mGCs with progesterone-rich conditioned media decreased expression of RGS11 without affecting PVR levels. Inhibition of progesterone signaling enhanced expression of both RGS11 and PVR. Expression in CCs was examined by means of global transcriptome sequencing analysis RGS11 and EPB41L3 increased in CCs during follicular maturation while PVR levels did not change. In conclusion, during human follicular maturation there are significant changes in expression of PVR, RGS11 and EPB41L3, possibly regulated by progesterone.