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STUDY QUESTION Does LH addition to FSH in vitro recover the human primary granulosa lutein cell (hGLC) sub/poor-response? SUMMARY ANSWER A picomolar concentration of LH may recover the FSH-induced cAMP and progesterone production of hGLC from sub/poor-responder women. WHAT is KNOWN ALREADY Clinical studies suggested that FSH and LH co-treatment may be beneficial for the ovarian response of sub/poor-responders undergoing ovarian stimulation during ART. STUDY DESIGN, SIZE, DURATION hGLC samples from 286 anonymous women undergoing oocyte retrieval for ART were collected from October 2017 to February 2021. PARTICIPANTS/MATERIALS, SETTING, METHODS hGLCs from women undergoing ovarian stimulation during ART were blindly purified, cultured, genotyped and treated in vitro by increasing concentrations of FSH (nM) ±0.5 nM LH. cAMP and progesterone levels produced after 3 and 24 h, respectively, were measured. In vitro data were stratified a posteriori, according to the donors’ ovarian response, into normo-, sub- and poor-responder groups and statistically compared. The effects of LH addition to FSH were compared with those obtained by FSH alone in all the groups as well. MAIN RESULTS AND THE ROLE of CHANCE hGLCs from normo-responders were shown to have higher sensitivity to FSH treatment than sub-/poor-responders in vitro. Equimolar FSH concentrations induced higher cAMP (about 2.5- to 4.2-fold), and progesterone plateau levels (1.2- to 2.1-fold), in cells from normo-responder women than those from sub-/poor-responders (ANOVA; P 0.05). Interestingly, these in vitro endpoints, collected from the normo-responder group treated with FSH alone, were similar to those obtained in the sub-/poor-responder group under FSH + LH treatment. No different allele frequencies and FSH receptor (FSHR) gene expression levels between groups were found, excluding genetics of gonadotropin and their receptors as a factor linked to the normo-, sub- and poor-response. In conclusion, FSH elicits phenotype-specific ovarian lutein cell response. Most importantly, LH addition may fill the gap between cAMP and steroid production patterns between normo- and sub/poor-responders. LIMITATIONS, REASONS FOR CAUTION Although the number of experimental replicates is overall high for an in vitro study, clinical trials are required to demonstrate if the endpoints evaluated herein reflect parameters of successful ART. hGLC retrieved after ovarian stimulation may not fully reproduce the response to hormones of granulosa cells from the antral follicular stage. WIDER IMPLICATIONS of THE FINDINGS This in vitro assay may describe the individual response to personalize ART stimulation protocol, according to the normo-, sub- and poor-responder status. Moreover, this in vitro study supports the need to conduct optimally designed, randomized clinical trials exploring the personalized use of LH in assisted reproduction. STUDY FUNDING/COMPETING INTEREST(S) This study was supported by Merck KGaA. M.L. and C.C. are employees of Merck KGaA or of the affiliate Merck Serono SpA. Other authors have no competing interests to declare. TRIAL REGISTRATION NUMBER N/A.

The advancement of Assisted Reproductive Technologies and the improvement in sperm freezing made male fertility preservation widely available. This study aims to evaluate the impact of cancer diseases on semen parameters before cryopreservation and the reproductive outcomes of patients who have thawed their semen samples.An observational, cohort study was conducted on cancer patients submitted to fertility preservation in AUSL-IRCCS of Reggio Emilia between 2007 and 2018. Semen samples were collected before cancer treatments, analysed and frozen by rapid freezing. On request, these samples were thawed for Assisted Reproductive Technologies procedures. Semen parameters were compared between testicular versus other cancers.we included 329 patients with a successful cryopreservation in 94.5% of cases. Testicular cancer was associated with lower sperm volumes (p=0.041) and lower total sperm concentration (p=0.009) compared to other cancers. No difference was observed about sperm motility and morphology, while oligozoospermia was significantly more frequent in men with testicular cancer (p0.001). In our cohort, the 8.4% of patients thawed their samples; the usage rate and the embryo transfer rate were significantly higher (p0.05) among those with a testicular cancer, while pregnancy and livebirth rates did not differ.male fertility preservation is feasible, easy to be performed, non-invasive and does not delay cancer treatments. Men affected by testicular cancer had worse semen parameters at cryopreservation but pregnancy and livebirth rates were similar to those achieved by men with other cancers and similar to those achieved with fresh sperm.

Purpose Several mathematical models have been developed to estimate individualized chances of assisted reproduction techniques (ART) success, although with limited clinical application. Our study aimed to develop a decisional algorithm able to predict pregnancy and live birth rates after controlled ovarian stimulation (COS) phase, helping the physician to decide whether to perform oocytes pick-up continuing the ongoing ART path. Methods A single-center retrospective analysis of real-world data was carried out including all fresh ART cycles performed in 1998–2020. Baseline characteristics, ART parameters and biochemical/clinical pregnancies and live birth rates were collected. A seven-steps systematic approach for model development, combining linear regression analyses and decision trees (DT), was applied for biochemical, clinical pregnancy, and live birth rates. Results Of fresh ART cycles, 12,275 were included. Linear regression analyses highlighted a relationship between number of ovarian follicles > 17 mm detected at ultrasound before pick-up (OF17), embryos number and fertilization rate, and biochemical and clinical pregnancy rates (p

In IVF centers, risk assessment applies to complex processes potentially accounting for adverse events and reactions that undergo well-established legislative oversight, and nonconformances (NCs), that lack of established tracking systems. NCs account for an integral part of the quality management system, so that their documentation is important. The study evaluated the performance of a customized tool for incident reporting (IR) to track and characterize NCs in a public IVF center. IVF operators used the IVF-customized IR tool to record NCs at the moment of detection or subsequently, and in a time-saving manner during daily practice. From February 2015 to February 2020, 635 NCs were reported leading to the implementation of 10 operative instructions and 3 procedures with corrective strategies. NCs referred to the IVF laboratory were the most numerically meaningful (454/635, 71.5%). The majority (352/454, 77.5%) accounted for NCs related to procedures of sample management; considering the analytical phase as all the procedures involving sample treatment, the intra-analytical phase (176/352, 50%) has always been more subject to NCs compared to pre- (102/352, 29%) and postanalytical (74/352, 21%) phases. Our experience showed that the IVF-customized IR tool is suitable for application in IVF with regard to NC reports and documentation, as it identifies the most vulnerable steps of treatments. It manages NCs over the time, but it requires a contextual understanding of its application in order to avoid NC underestimates that could negatively influence the safety and quality aspects of IVF treatments.

The predictive role of sperm motility and morphology was recently detected in a large sample of more than 20000 assisted reproductive technology (ART) fresh cycles. However, the complete ART procedure consisted of both fresh and frozen-embryos transfers and only a comprehensive evaluation of the entire process could really confirm if these parameters really predict the ART success. The aim of the study was to evaluate which sperm parameter could predict the success of ART.A retrospective, real-world data analysis was performed, enrolling all couples attending ART from 2008 to 2021, including both fresh and frozen cycles and both in vitro fertilization (IVF) and intra-cytoplasmic sperm injection (ICSI) procedures.Fresh cycles success (considering live birth rate) was predicted by female age (1.04 [1.02-1.06]), injected oocytes (0.96 [0.93-0.99]), embryo number (0.79 [0.75-0.83]) and progressive sperm motility (0.98 [0.97-0.99]). On the contrary, frozen cycle outcomes were predicted only by sperm motility (0.97 [0.95-0.99]). This prediction was confirmed in IVF but not in ICSI cycles.Both female and male parameters predicted the ART success considering the entire path. However, frozen cycle success was predicted only by progressive sperm motility in IVF cycles, suggesting that the potential amelioration of this male parameter is relevant to improve ART success. Those couples expected to obtain the highest embryos after fertilization (low female age and better semen parameters) will have more attempts with frozen cycles and thus would benefit from a potential treatment focused to improve sperm parameters.

The tumor microenvironment (TME) includes immune (T, B, NK, dendritic), stromal, mesenchymal, endothelial, adipocytic cells, extracellular matrix, and cytokines/chemokines/soluble factors regulating various intracellular signaling pathways (ISP) in tumor cells. TME influences the survival/progression of prostate cancer (PC), enabling tumor cell immune-evasion also through the activation of the PD-1/PD-L1 axis. We have performed a systematic literature review according to the PRISMA guidelines, to investigate how the PD-1/PD-L1 pathway is influenced by TME and ISPs. Tumor immune-escape mechanisms include suppression/exhaustion of tumor infiltrating cytotoxic T lymphocytes, inhibition of tumor suppressive NK cells, increase in immune-suppressive immune cells (regulatory T, M2 macrophagic, myeloid-derived suppressor, dendritic, stromal, and adipocytic cells). IFN-γ (the most investigated factor), TGF-β, TNF-α, IL-6, IL-17, IL-15, IL-27, complement factor C5a, and other soluble molecules secreted by TME components (and sometimes increased in patients’ serum), as well as and hypoxia, influenced the regulation of PD-L1. Experimental studies using human and mouse PC cell lines (derived from either androgen-sensitive or androgen-resistant tumors) revealed that the intracellular ERK/MEK, Akt-mTOR, NF-kB, WNT and JAK/STAT pathways were involved in PD-L1 upregulation in PC. Blocking the PD-1/PD-L1 signaling by using immunotherapy drugs can prevent tumor immune-escape, increasing the anti-tumor activity of immune cells.

Immunotherapy targeting the PD-1–PD-L1 axis yielded good results in treating different immunologically ‘‘hot’’ tumors. A phase II study revealed good therapeutic activity of pembrolizumab in selected prostatic carcinoma (PC)-patients. We performed a systematic literature review (PRISMA guidelines), which analyzes the immunohistochemical expression of PD-L1 in human PC samples and highlights the pre-analytical and interpretation variables. Interestingly, 29% acinar PCs, 7% ductal PCs, and 46% neuroendocrine carcinomas/tumors were PD-L1+ on immunohistochemistry. Different scoring methods or cut-off criteria were applied on variable specimen-types, evaluating tumors showing different clinic-pathologic features. The positivity rate of different PD-L1 antibody clones in tumor cells ranged from 3% (SP142) to 50% (ABM4E54), excluding the single case tested for RM-320. The most tested clone was E1L3N, followed by 22C3 (most used for pembrolizumab eligibility), SP263, SP142, and 28-8, which gave the positivity rates of 35%, 11–41% (depending on different scoring systems), 6%, 3%, and 15%, respectively. Other clones were tested in

Study question Evaluation of the effect of varicocele correction on conventional and microscopic seminal parameters and evaluation of which factors might predict sperm improvement after surgical treatment. Summary answer The detailed morphologic sperm evaluation has been identified as a novel parameter expressing the post-surgical semen amelioration after varicocelectomy. What is known already Generally, varicocele develops during puberty and occurs more often on the left side for anatomic reasons. However, its diagnosis is commonly delayed, especially in asymptomatic cases, until the man consults an andrologist for couple infertility. A causative relationship between varicocele and impairment of semen quality has been largely investigated in the context of male infertility. Despite the florid literature available on this topic, the clinical benefit in terms of semen quality improvement after varicocele surgical repair remains controversial. Study design, size, duration An observational, retrospective clinical trial was carried out including patients undergoing surgical treatment for varicocele at the Day Surgery of the Urology Operative Unit of the Santa Maria Nuova Hospital-IRCCS of Reggio Emilia from September 2011 to March 2020. Primary outcome was the detailed morphologic microscopic sperm evaluation. Secondary outcomes were conventional semen analyses. Each patient was considered two times (before and after the surgery) and evaluated by both physical examination and ultrasonography. Participants/materials, setting, methods The inclusion criteria considered the patients with diagnosis of varicocele at ultrasound examination, attending surgical resolution and with at semen analyses before and after the surgery, were excluded patients with diagnosis of varicocele without surgical indication, and/or semen analyses performed only before or only after the surgery. In the statistical analysis a logistic multivariate regression analysis was performed in order to evaluate the change before and after surgery. Main results and the role of chance The post-surgical semen analysis was performed after a mean of 183.7 + 112.5 days since the surgery for a total of 121 males (mean age 24.6 + 4.1 years) enrolled. The surgical treatment leads to a significant increase in sperm concentration (p = 0.015) and percentage of progressive and total motility (p = 0.022 and p = 0.039, respectively), with a significant decrease in the percentage of immobile sperms (p = 0.013). In particular, semen concentration improved in 71.7% of patients (p = 0.010). Considering the detailed morphologic microscopic evaluation, a significant improvement was detected: head abnormalities showed a significant reduction, considering microcephaly (3.3 + 3.6 versus 2.2 + 2.9%, p = 0.015), macrocephaly (1.4 + 0.6 versus 1.2 + 0.9%, p = 0.043) and cytoplasmic appendix (1.4 + 0.8 versus 0.9 + 1.2%, p = 0.041). Moreover, surgery led to a significant reduction of tails abnormalities, considering absence (0.6 +2.3 versus 0.1 + 0.7, p = 0.048) and coiled tail (5.2 + 1.5 versus 6.6 + 2.0, p = 0.037). Thus, surgical varicocele resolution leads to a significant improvement in specific morphological semen parameters. The multivariate logistic analysis identified the ultrasound varicocele degree before surgery as a main predictor of the sperm concentration improvement (p = 0.016). The semen parameters improvement was higher for varicocele of I and II degree (p = 0.008). Limitations, reasons for caution The retrospective study design precluded from carrying out a case-control study to compare the surgical techniques. Moreover, the study design limited the availability of patients’ clinical data in order to performed a more comprehensive predictive analysis. Wider implications of the findings Using a complex statistical approach, it emerged that the greatest improvement in semen quality was obtained in case of mild varicocele, increasing the knowledge on the therapeutic potential of surgery. This result has clinical implications, since it could help to select those patients ‘to treat or not to treat’. Trial registration number none

Study question Evaluate the population attending Assisted reproductive techniques (ART) who have suffered the interruption of fertilization paths because of the SARS-CoV–2 italian national lockdown declared under goverment provision. Summary answer The research show that some infertile couples candidate to ART paths obtained a spontaneous pregnancy during the lockdown due to SARS-CoV–2 pandemic. What is known already The real impact of psychological stress on couple infertility in terms of pregnancies obtained is largely under-investigated in the literature and the potential low frequency of sexual activity is usually poorly considered in the management of couple infertility and its role on pregnancies failure is unclear, but probably underestimated. Moreover, the worldwide spread of the SARS-CoV–2 infection has profoundly affected all aspects of human life, with tangible consequences in several contexts, including reproduction. This allowed to highlight the interrelation between psychological distress and reproductive medicine are still conflicting. Study design, size, duration This is a study conducted at the Fertility Centre of the Department of Obstetrics and Gynaecology of Reggio Emilia (Italy), that evaluated the conception ability of couples who suffered the postponement of ART cycles during the SARS-CoV–2 pandemic. In particular, we collected anamnestic, anthropometrical and demographic data of those women attending ART straddling the lockdown period, from March 2020 to April 2020. Participants/materials, setting, methods The study evaluated couples attending ART, who had an interruption of the fertilization paths due to the SARS-CoV–2 pandemic. The variables as women age, BMI, duration of infertility, number of sexual intercourses per week and infertility aetiology were considered in a multivariate logistic analysis. The statistical analysis was performed setting pregnancy (categorical data) as the dependent variable, and all other available data as either covariates or cofactors. Main results and the role of chance Among the 431 couples recalled to reschedule ART cycles 34 couples (7.9%) obtained a spontaneous pregnancy during the COVID–19 lockdown. The statistical analysis for the 431 couples recalled showed that average duration of couple infertility was 3.5 ± 2.8 years, while an exclusively female causal factor was observed in the 23.7% of cases (102 couples), an exclusively male one in the 32.7% (141 couples), a coexistence of male/female factor in the 18.6% (80 couples), and an idiopathic form in the 25.1% (108 couples). The 34 couples obtained a spontaneous pregnancy presented a female infertility factor in the 26.5% of cases (9 couples), a male factor in the 29.4% (10 couples), a male/female factor in the 11.8% (4 couples), and idiopathic infertility in the 32.4% (11 couples). The male factor of infertility was not evaluated in all couples, thus this definition came from the anamnestic evaluation of the couple. In a multivariate logistic analysis we highlighted that the infertility history duration and the sexual intercourses frequency were significantly related to pregnancy (F = 4.8, degrees of freedom=1, p = 0.030 and F = 81.6, degrees of freedom=1, p Limitations, reasons for caution Despite the short observation period (two months of italian national lockdown declared under goverment provision), the large sample size of women evaluated attending to a single ART centre constitutes a point of strength of our study. However, the absence of a control group represents the most important limit. Wider implications of the findings: In conclusion, the lockdown allowed to increase the knowledge about under-explored causes of idiopathic infertility: the frequency of sexual intercourses. This aspect in reproductive medicine could help to identify those couples able to conceive spontaneously, avoiding unnecessary over-treatment, and to correctly apply ART to those couples who really need it. Trial registration number none

Many studies have investigated the potential prognostic and predictive role of PD-L1 in prostatic carcinoma (PC). We performed a systematic literature review (PRISMA guidelines) to critically evaluate human tissue-based studies (immunohistochemistry, molecular analysis, etc.), experimental research (cell lines, mouse models), and clinical trials. Despite some controversial results and study limitations, PD-L1 expression by tumor cells may be related to clinic–pathologic features of adverse outcome, including advanced tumor stage (high pT, presence of lymph node, and distant metastases), positivity of surgical margins, high Grade Group, and castration resistance. Different PD-L1 positivity rates may be observed in matched primary PCs and various metastatic sites of the same patients. Over-fixation, type/duration of decalcification, and PD-L1 antibody clone may influence the immunohistochemical analysis of PD-L1 on bone metastases. PD-L1 seemed expressed more frequently by castration-resistant PCs (49%) as compared to hormone-sensitive PCs (17%). Some series found that PD-L1 positivity was associated with decreased time to castration resistance. Treatment with ipilimumab, cyclophosphamide/GVAX/degarelix, or degarelix alone may increase PD-L1 expression. Correlation of PD-L1 positivity with overall survival and outcomes related to tumor recurrence were rarely investigated; the few analyzed series produced conflicting results and sometimes showed limitations. Further studies are required. The testing and scoring of PD-L1 should be standardized.

Setting: A causative relationship between varicocele and impairment of semen quality has been largely investigated in the context of male infertility, although its clinical benefit remains controversial.Objective: To investigate the effect of varicocele correction on detailed morphologic microscopic semen parameters in a large homogeneous cohort of patients and to evaluate which factors could predict semen improvement after the surgical treatment.Design: An observational, retrospective cohort study was carried out including all patients undergoing surgical treatment for varicocele from September 2011 to March 2020 in the same clinical centre. Enrolled males performed at least one semen analysis before and one after surgical varicocele correction. Primary outcome was the detailed morphologic microscopic sperm evaluation. Secondary outcomes were conventional semen analyses.Results: 121 males (mean age 24.6+6.1 years) were enrolled. Using detailed morphologic microscopic sperm evaluation, a significant morphological improvement was recorded, with a reduction in head and tail abnormalities. Moreover, a significant increase in sperm concentration (p=0.015) and percentage of progressive and total motility (p=0.022 and p=0.039) were observed after surgery. The multivariate logistic analysis identified the ultrasonography varicocele degree before surgery as a main predictor of the sperm concentration improvement (p=0.016), with the highest improvement for varicocele of I and II degree. Conclusion: For the first time, the detailed morphologic microscopic sperm evaluation highlights a relevant reduction in sperm abnormalities after varicocele surgery, showing its potential application in clinical practice.

Liquid biopsy is an accessible, non-invasive diagnostic tool for advanced prostate cancer (PC) patients, potentially representing a real-time monitoring test for tumor evolution and response to treatment through the analysis of circulating tumor cells (CTCs) and exosomes. We performed a systematic literature review (PRISMA guidelines) to describe the current knowledge about PD-L1 expression in liquid biopsies of PC patients: 101/159 (64%) cases revealed a variable number of PD-L1+ CTCs. Outcome correlations should be investigated in larger series. Nuclear PD-L1 expression by CTCs was occasionally associated with worse prognosis. Treatment (abiraterone, enzalutamide, radiotherapy, checkpoint-inhibitors) influenced PD-L1+ CTC levels. Discordance in PD-L1 status was detected between primary vs. metastatic PC tissue biopsies and CTCs vs. corresponding tumor tissues. PD-L1 is also released by PC cells through soluble exosomes, which could inhibit the T cell function, causing immune evasion. PD-L1+ PC-CTC monitoring and genomic profiling may better characterize the ongoing aggressive PC forms compared to PD-L1 evaluation on primary tumor biopsies/prostatectomy specimens (sometimes sampled a long time before recurrence/progression). Myeloid-derived suppressor cells and dendritic cells (DCs), which may have immune-suppressive effects in tumor microenvironment, have been found in PC patients circulation, sometimes expressing PD-L1. Occasionally, their levels correlated to clinical outcome. Enzalutamide-progressing castration-resistant PC patients revealed increased PD-1+ T cells and circulating PD-L1/2+ DCs.

In prostate cancer (PC), the PD-1/PD-L1 axis regulates various signaling pathways and it is influenced by extracellular factors. Pre-clinical experimental studies investigating the effects of various treatments (alone or combined) may discover how to overcome the immunotherapy-resistance in PC-patients. We performed a systematic literature review (PRISMA guidelines) to delineate the landscape of pre-clinical studies (including cell lines and mouse models) that tested treatments with effects on PD-L1 signaling in PC. NF-kB, MEK, JAK, or STAT inhibitors on human/mouse, primary/metastatic PC-cell lines variably down-modulated PD-L1-expression, reducing chemoresistance and tumor cell migration. If PC-cells were co-cultured with NK, CD8+ T-cells or CAR-T cells, the immune cell cytotoxicity increased when PD-L1 was downregulated (opposite effects for PD-L1 upregulation). In mouse models, radiotherapy, CDK4/6-inhibitors, and RB deletion induced PD-L1-upregulation, causing PC-immune-evasion. Epigenetic drugs may reduce PD-L1 expression. In some PC experimental models, blocking only the PD-1/PD-L1 pathway had limited efficacy in reducing the tumor growth. Anti-tumor effects could be increased by combining the PD-1/PD-L1 blockade with other approaches (inhibitors of tyrosine kinase, PI3K/mTOR or JAK/STAT3 pathways, p300/CBP; anti-RANKL and/or anti-CTLA-4 antibodies; cytokines; nitroxoline; DNA/cell vaccines; radiotherapy/Radium-223).

Commercial hMG drugs are marketed for the treatment of infertility and consist of highly purified hormones acting on receptors expressed in target gonadal cells. Menopur® and Meriofert® are combined preparation of FSH and hCG and are compared in vitro herein. To this purpose, the molecular composition of the two drugs was analyzed by immunoassay. The formation of FSH receptor and LH/hCG receptor (FSHR; LHCGR) heteromer, intracellular Ca2+ and cAMP activation, β-arrestin 2 recruitment and the synthesis of progesterone and estradiol were evaluated in transfected HEK293 and human primary granulosa lutein cells treated by drugs administered within the pg-mg/ml concentration range. Molecular characterization revealed that Meriofert® has a higher FSH:hCG ratio than Menopur® which, in turn, displays the presence of LH molecules. While both drugs induced similar FSHR-LHCGR heteromeric formations and intracellular Ca2+ increase, Meriofert® had a higher potency than Menopur® in inducing a cAMP increase. Moreover, Meriofert® revealed a higher potency than Menopur® in recruiting β-arrestin 2, likely due to different FSH content modulating the tridimensional structure of FSHR-LHCGR-β-arrestin 2 complexes, as evidenced by a decrease in bioluminescence resonance energy transfer signal. This drug-specific activation of intracellular signaling pathways is consistent with the molecular composition of these preparations and impacts downstream progesterone and estradiol production, with Menopur® more potent than Meriofert® in inducing the synthesis of both the steroids. These findings are suggestive of distinct in-vivo activities of these preparations, but require cautious interpretation and further validation from clinical studies.

Mechanisms regulating the selection of antral ovarian follicles are poorly understood and supposed to rely on low estrogen levels, decline of follicle-stimulating hormone (FSH) levels and receptor (FSHR) expression. These concepts are challenged in vitro, where apoptosis of human granulosa cells (hGLC) and transfected cell lines is induced by high doses of FSH or FSHR overexpression, while estrogens induce anti-apoptotic signals via nuclears and a G protein-coupled estrogen receptor (GPER). Therefore, in vitro data suggest that antral follicle selection may be driven by underestimated, FSH/FSHR-dependent apoptotic signals due to transiently maximized FSHR expression and overload of cAMP signalling, prevailing on estrogen-dependent signals. Here we demonstrate how FSHR/GPER physical interaction rescue ovarian follicles from FSH-mediated death. 10 nM FSH induces high intracellular levels of cAMP, measured by bioluminescence resonance energy transfer (BRET), and apoptosis in cultured hGLC under conditions where GPER levels are depleted by siRNA. This result was confirmed in transfected HEK293 cells overexpressing FSHR. Using BRET, photo-activated localization microscopy (PALM) and bioinformatics prodiction, we also demonstrate FSHR/GPER heteromers at the cell surface. The role of FSHR/GPER heteromers may be relevant to inhibit FSH-induced death signals, since increasing GPER expression levels in HEK293 cells co-expressing FSHR results in displacement of the Gαs-protein to FSHR, blockade of FSH-induced cAMP production and inhibition of apoptosis. However, in HEK293 cells coexpressing GPER/FSHR, FSH-induced activation of the anti-apoptotic AKT-pathway via a Gβγ-dependent mechanism, as demonstrated by Western blotting in cells treated using the inhibitor gallein. Inhibition of both FSH-induced cAMP production and apoptosis was lost when FSHR is coexpressed together with a mutant GPER, unable to heteromerize with FSHR, as well as in KO HEK293 cells unable to produce a molecular complex associated with GPER inhibiting cAMP. GPER/FSHR coexpression is confirmed in secondary follicles from paraffin-embedded tissues of human ovary by immunohistochemistry, suggesting that FSHR-GPER heterodimers could be physiologically relevant in vivo for inhibiting cAMP-linked apoptosis. Most importantly, FSHR and GPER co-expression correlates in hGLC from FSH-normo-responder women undergoing assisted reproduction, while it is not in hGLC from FSH-poor-responders, where increasing FSHR mRNA levels do not correspond to increasing GPER mRNA levels. We demonstrate that death signals in atretic follicles are delivered through overexpressed FSHR and inhibited by FSHR/GPER heteromerization, activating anti-apoptotic pathways. This finding unveils a novel working model of the physiology of dominant follicle selection and the relationship between FSH and estrogens.

Classically, follicle stimulating hormone receptor (FSHR) driven cAMP-mediated signaling boosts human ovarian follicle growth and would be essential for oocyte maturation. However, contradicting in vitro suggest a different view on physiological and clinical significance of FSHR-mediated cAMP signaling. We found that the G protein coupled estrogen receptor (GPER) heteromerizes with FSHR, reprogramming cAMP/death signals into proliferative stimuli fundamental for sustaining oocyte survival. In human granulosa cells, survival signals are effectively delivered upon equal expression levels of both receptors, while they are missing at high FSHR:GPER ratio, which negatively impacts follicle maturation and strongly correlates with FSH responsiveness of patients undergoing controlled ovarian stimulation. Consistent with high FSHR expression levels during follicular selection, cell viability is dramatically reduced in FSHR overexpressing cells due to preferential coupling to the Gαs protein/cAMP pathway. In contrast, FSHR/GPER heteromer formation resulted in FSH-triggered anti-apoptotic/proliferative signaling delivered via the Gβγ dimer while heteromer impairment or GPER-associated Gαs inhibitory protein complexes resulted in cell death. GPER-depleted granulosa cells have an amplified FSH-dependent decrease in cell viability and steroidogenesis, consistent with the requirement of estrogen signaling for successful oocyte growth. Therefore, our findings indicate how oocyte maturation depends on the capability of GPER to shape FSHR selective signals, indicating hormone receptor heteromers may be a marker of cell proliferation.One Sentence SummaryFSHR/GPER heteromers block cAMP-dependent selection of ovarian follicles and target tumor growth and poor FSH-response in women.