Regulation of Male Fertility by the Renin-Angiotensin System

The renin-angiotensin system (RAS) is a peptidic system known mainly for its roles in the maintenance of blood pressure and electrolyte and fluid homeostasis. However, several tissues and cells have been described to possess an intrinsic RAS that acts locally through different paracrine and autocrine mechanisms. In the male reproductive system, several components of this system have been observed in various organs and tissues, such as the testes, spermatozoa and seminal fluid. Some functions attributed to this local RAS are maintenance of seminal plasma electrolytes, regulation of steroidogenesis and spermatogenesis, and sperm functions. However, their specific actions in these locations are not fully understood. Therefore, a deep knowledge of the functions of the RAS at both the testicular and seminal levels could clarify its roles in male infertility and sperm physiology, and the different RAS elements could be used to design tools enabling the diagnosis and/or treatment of male infertility.This study was supported by grants from the Basque Government (GIC12/173) and University of the Basque Country (UPV/EHU) (EHUA14/17)

(Pro)renin Receptor Is Present in Human Sperm and It Adversely Affects Sperm Fertility Ability

Sperm fertility ability may be modulated by different molecular systems, such as the renin-angiotensin system (RAS). Although renin is one of its most relevant peptides, the presence and role of the (pro)renin receptor (PRR) is completely unknown. We have proved for the first time the existence of PRR and its transcript in human sperm by western blot and RT-PCR. Immunofluorescence studies showed that this receptor is mainly located in the apical region over the acrosome and in the postacrosomal region of the sperm head and along the sperm tail. In addition, this prospective cohort study also proves that semen samples with higher percentages of PRR-positive spermatozoa are associated with poor sperm motility, worse blastocyst development and no-viable blastocysts. Our results provide insight into how PRR play a negative role in sperm physiology that it may condition human embryo quality and development. An in-depth understanding of the role of PRR in sperm fertility can help elucidate its role in male infertility, as well as establish biomarkers for the diagnosis or selection of sperm to use during assisted reproductive techniques.This research was funded by grants from the Basque Government (GIC12/173; to M.G. and I.M.-H.) and University of the Basque Country (UPV/EHU; to M.G. and I.U.-A.) (EHUA14/17)

The Multifunctional Role of SPANX-A/D Protein Subfamily in the Promotion of Pro-Tumoural Processes in Human Melanoma

Human sperm protein associated with the nucleus on the X chromosome (SPANX) genes encode a protein family (SPANX-A, -B, -C and -D), whose expression is limited to the testis and spermatozoa in normal tissues and various tumour cells. SPANX-A/D proteins have been detected in metastatic melanoma cells, but their contribution to cancer development and the underlying molecular mechanisms of skin tumourigenesis remain unknown. Combining functional and proteomic approaches, the present work describes the presence of SPANX-A/D in primary and metastatic human melanoma cells and how it promotes pro-tumoural processes such as cell proliferation, motility and migration. We provide insights into the molecular features of skin tumourigenesis, describing for the first time a multifunctional role of the SPANX-A/D protein family in nuclear function, energy metabolism and cell survival, considered key hallmarks of cancer. A better comprehension of the SPANX-A/D protein subfamily and its molecular mechanisms will help to describe new aspects of tumour cell biology and develop new therapeutic targets and tumour-directed pharmacological drugs for skin tumoursUniversity of the Basque Country (UPV/EHU) (GIU19/018). IU-A is supported by a fellowship from the University of the Basque Country (UPV/EHU). IM-H is supported by a fellowship from the Basque Government

Wnt-3a Induces Epigenetic Remodeling in Human Dental Pulp Stem Cells

Dental pulp stem cells (DPSCs) from adult teeth show the expression of a very complete repertoire of stem pluripotency core factors and a high plasticity for cell reprogramming. Canonical Wnt and Notch signaling pathways regulate stemness and the expression of pluripotency core factors in DPSCs, and even very short-term (48 h) activations of the Wnt pathway induce a profound remodeling of DPSCs at the physiologic and metabolic levels. In this work, DPSC cultures were exposed to treatments modulating Notch and Wnt signaling, and also induced to differentiate to osteo/adipocytes. DNA methylation, histone acetylation, histone methylation, and core factor expression levels where assessed by mass spectroscopy, Western blot, and qPCR. A short-term activation of Wnt signaling by WNT-3A induced a genomic DNA demethylation, and increased histone acetylation and histone methylation in DPSCs. The efficiency of cell reprogramming methods relies on the ability to surpass the epigenetic barrier, which determines cell lineage specificity. This study brings important information about the regulation of the epigenetic barrier by Wnt signaling in DPSCs, which could contribute to the development of safer and less aggressive reprogramming methodologies with a view to cell therapy.This work was funded by the UPV/EHU (GIU16/66, UFI 11/44; to F.U.), the Basque Government (GV/EJ; Ikerketa Taldeak IT831-13; to G.I. and ELKARTEK KK-2019-00093; to F.U.) and ISCIII (DTS18/00142; to N.S.)

microRNA-based signatures obtained from endometrial fluid identify implantative endometrium

STUDY QUESTION Is it possible to use free and extracellular vesicle-associated microRNAs (miRNAs) from human endometrial fluid (EF) samples as non-invasive biomarkers for implantative endometrium? SUMMARY ANSWER The free and extracellular vesicle-associated miRNAs can be used to detect implantative endometrium in a non-invasive manner. WHAT IS KNOWN ALREADY miRNAs and extracellular vesicles (EVs) from EF have been described as mediators of the embryo-endometrium crosstalk. Therefore, the analysis of miRNA from this fluid could become a non-invasive technique for recognizing implantative endometrium. This analysis could potentially help improve the implantation rates in ART. STUDY DESIGN, SIZE, DURATION In this prospective study, we first optimized different protocols for EVs and miRNA analyses using the EF of a setup cohort (n = 72). Then, we examined differentially expressed miRNAs in the EF of women with successful embryo implantation (discovery cohort n = 15/validation cohort n = 30) in comparison with those for whom the implantation had failed (discovery cohort n = 15/validation cohort n = 30). Successful embryo implantation was considered when pregnancy was confirmed by vaginal ultrasound showing a gestational sac 4 weeks after embryo transfer (ET). PARTICIPANTS/MATERIALS, SETTING, METHODS The EF of the setup cohort was obtained before starting fertility treatment during the natural cycle, 16-21 days after the beginning of menstruation. For the discovery and validation cohorts, the EF was collected from women undergoing frozen ET on Day 5, and the samples were collected immediately before ET. In this study, we compared five different methods; two of them based on direct extraction of RNA and the other three with an EV enrichment step before the RNA extraction. Small RNA sequencing was performed to determine the most efficient method and find a predictive model differentiating between implantative and non-implantative endometrium. The models were confirmed using quantitative PCR in two sets of samples (discovery and validation cohorts) with different implantation outcomes. MAIN RESULTS AND THE ROLE OF CHANCE The protocols using EV enrichment detected more miRNAs than the methods based on direct RNA extraction. The two most efficient protocols (using polymer-based precipitation (PBP): PBP-M and PBP-N) were used to obtain two predictive models (based on three miRNAs) allowing us to distinguish between an implantative and non-implantative endometrium. The first Model 1 (PBP-M) (discovery: AUC = 0.93; P-value = 0.003; validation: AUC = 0.69; P-value = 0.019) used hsa-miR-200b-3p, hsa-miR-24-3p and hsa-miR-148b-3p. Model 2 (PBP-N) (discovery: AUC = 0.92; P-value = 0.0002; validation: AUC = 0.78; P-value = 0.0002) used hsa-miR-200b-3p, hsa-miR-24-3p and hsa-miR-99b-5p. Functional analysis of these miRNAs showed strong association with key implantation processes such as in utero embryonic development or transforming growth factor-beta signaling. LARGE SCALE DATA The FASTQ data are available in the GEO database (access number GSE178917). LIMITATIONS, REASONS FOR CAUTION One important factor to consider is the inherent variability among the women involved in the trial and among the transferred embryos. The embryos were pre-selected based on morphology, but neither genetic nor molecular studies were conducted, which would have improved the accuracy of our tests. In addition, a limitation in miRNA library construction is the low amount of input RNA. WIDER IMPLICATIONS OF THE FINDINGS We describe new non-invasive protocols to analyze miRNAs from small volumes of EF. These protocols could be implemented in clinical practice to assess the status of the endometrium before attempting ET. Such evaluation could help to avoid the loss of embryos transferred to a non-implantative endometrium. STUDY FUNDING/COMPETING INTEREST(S) J.I.-P. was supported by a predoctoral grant from the Basque Government (PRE_2017_0204). This study was partially funded by the Grant for Fertility Innovation (GFI, 2011) from Merck (Darmstadt, Germany). It was also supported by the Spanish Ministry of Economy and Competitiveness MINECO within the National Plan RTI2018-094969-B-I00, the European Union's Horizon 2020 research and innovation program (860303), the Severo Ochoa Centre of Excellence Innovative Research Grant (SEV-2016-0644) and the Instituto de Salud Carlos III (PI20/01131). The funding entities did not play any role in the study design, collection, analysis and interpretation of data, writing of the report or the decision to submit the article for publication. The authors declare no competing interests.J.I.-P. was supported by a predoctoral grant from the Basque Government (PRE_2017_0204). This study was partially funded by the Grant for Fertility Innovation (GFI, 2011) from Merck (Darmstadt, Germany). The project was also supported by the Spanish Ministry of Economy and Competitiveness MINECO within the national plan RTI2018-094969-B-I00, the European Union's Horizon 2020 research and innovation program (860303), the Severo Ochoa Centre of Excellence Innovative Research Grant (SEV-2016-0644) and the Instituto de Salud Carlos III (PI20/01131). The funding entities did not have any role in study design, sample collection, analysis and interpretation of data, report writing or decision to submit the article for publication

Pirin is a prognostic marker of human melanoma that dampens the proliferation of malignant cells by downregulating JARID1B/KDM5B expression

Originally considered to act as a transcriptional co‑factor, Pirin has recently been reported to play a role in tumorigenesis and the malignant progression of many tumors. Here, we have analyzed the diagnostic and prognostic value of Pirin expression in the early stages of melanoma, and its role in the biology of melanocytic cells. Pirin expression was analyzed in a total of 314 melanoma biopsies, correlating this feature with the patient’s clinical course. Moreover, PIR downregulated primary melanocytes were analyzed by RNA sequencing, and the data obtained were validated in human melanoma cell lines overexpressing PIR by functional assays. The immunohistochemistry multivariate analysis revealed that early melanomas with stronger Pirin expression were more than twice as likely to develop metastases during the follow‑up. Transcriptome analysis of PIR downregulated melanocytes showed a dampening of genes involved in the G1/S transition, cell proliferation, and cell migration. In addition, an in silico approach predicted that JARID1B as a potential transcriptional regulator that lies between PIR and its downstream modulated genes, which was corroborated by co‑transfection experiments and functional analysis. Together, the data obtained indicated that Pirin could be a useful marker for the metastatic progression of melanoma and that it participates in the proliferation of melanoma cells by regulating the slow‑cycling JARID1B gene.This project was supported by grants from the Basque Government (KK2017-041 and KK2020-00069 to M.D.B.), the UPV/EHU (GIU17/066 to M.D.B.), H2020-ESCEL JTI (15/01 to M.D.B.) and MINECO (PCIN-2015-241 to M.D.B.). CP holds a predoctoral fellowship from the Basque Government. Part of this project is under European patent No. EP3051291 (EP14796149.4): “Method for diagnosis and prognosis of cutaneous melanoma”, Univer- sity of the Basque Country (UPV/EHU). The authors acknowledge the technical support SGIker resources at the UPV/EHU for the computational calculations, which were carried out in the Arina Informatics Cluster. The authors are grateful to the Basque Biobank for providing the biopsy samples and in particular, to María Jesús Fernández and Arantza Perez Dobaran for their technical support with the immunohistochemistry

Expression and Localization of Opioid Receptors in Male Germ Cells and the Implication for Mouse Spermatogenesis

The presence of endogenous opioid peptides in different testicular cell types has been extensively characterized and provides evidence for the participation of the opioid system in the regulation of testicular function. However, the exact role of the opioid system during the spermatogenesis has remained controversial since the presence of the mu-, delta-and kappa-opioid receptors in spermatogenic cells was yet to be demonstrated. Through a combination of quantitative real-time PCR, immunofluorescence, immunohistochemistry and flow cytometry approaches, we report for the first time the presence of active mu-, deltaand kappa-opioid receptors in mouse male germ cells. They show an exposition time-dependent response to opioid agonist, hence suggesting their active involvement in spermatogenesis. Our results contribute to understanding the role of the opioid receptors in the spermatogenesis and could help to develop new strategies to employ the opioid system as a biochemical tool for the diagnosis and treatment of male infertility.This work was supported by grants from The Basque Government, University of the Basque Country (UPV/EHU) and Merck Serono. HE was supported by a fellowship from the Gangoti Barrera Foundation; MG was supported by a fellowship from Basque Government (Zabalduz); IM was supported by a fellowship from Basque Government and IU was supported by a fellowship from University of Basque Country (UPV/EHU). The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript. This does not alter the authors' adherence to PLOS ONE policies on sharing data and materials. This work was supported by grants from The Basque Government, University of the Basque Country (UPV/EHU) and Merck Serono. HE was supported by a fellowship from the Gangoti Barrera Foundation; MG was supported by a fellowship from Basque Government (Zabalduz); IM was supported by a fellowship from Basque Government and IU was supported by a fellowship from University of Basque Country (UPV/EHU). The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript. This does not alter our adherence to PLOS ONE policies on sharing data and materials

Human Sperm Testicular Angiotensin Converting Enzyme Helps Determine Human Embryo Quality

Angiotensin-converting enzyme functions in the male reproductive system, but the extent of its function in reproduction is not fully understood. The primary objective of this work was to investigate the relationship between the testicular isoform of angiotensin-converting enzyme present in human spermatozoa and semen parameters, human embryo quality, and assisted reproduction success. A total of 81 semen samples and 635 embryos from couples undergoing oocyte donation cycles at the IVI Bilbao Clinic were analyzed. Semen parameters, embryos quality, and blastocyst development were examined according to the World Health Organization standards and the Spanish Association of Reproduction Biology Studies criteria. The percentage of testicular angiotensin-converting enzyme-positive spermatozoa and the number of molecules per spermatozoon were analyzed by flow cytometry. Both parameters were inversely correlated with human sperm motility. Higher percentages of testicular angiotensin-converting enzyme-positive spermatozoa together with fewer enzyme molecules per spermatozoon were positively correlated with better embryo quality and development. Our results suggest that embryos with a higher implantation potential come from semen samples with higher percentages of testicular angiotensin-converting enzyme-positive cells and fewer enzyme molecules per spermatozoon. Based on these findings, we propose that testicular angiotensin-converting enzyme could be used to aid embryologists in selecting better semen samples for obtaining high-quality blastocysts during in vitro fertilization procedures.The authors thank Alejandro Diez, Ph.D., technician of the Analytical and High-Resolution Microscopy and Cytometry Laboratory in Biomedicine Service of the University of Basque Country (UPV/EHU), for his technical assistance with samples processing by flow cytometry. This study was supported by grants from the Basque Government (GIC12/173; to MG and IMH) and University of the Basque Country (UPV/EHU) (EHUA14/17; to MG and IUA)

The Voltage-Gated Sodium Channel Na(v)1.8 Is Expressed in Human Sperm

The role of Na+ fluxes through voltage-gated sodium channels in the regulation of sperm cell function remains poorly understood. Previously, we reported that several genes encoding voltage-gated Na+ channels were expressed in human testis and mature spermatozoa. In this study, we analyzed the presence and function of the TTX-resistant VGSC a subunit Na(v)1.8 in human capacitated sperm cells. Using an RT-PCR assay, we found that the mRNA of the gene SCN10A, that encode Na-v1.8, was abundantly and specifically expressed in human testis and ejaculated spermatozoa. The Na-v1.8 protein was detected in capacitated sperm cells using three different specific antibodies against this channel. Positive immunoreactivity was mainly located in the neck and the principal piece of the flagellum. The presence of Na-v1.8 in sperm cells was confirmed by Western blot. Functional studies demonstrated that the increases in progressive motility produced by veratridine, a voltage-gated sodium channel activator, were reduced in sperm cells preincubated with TTX (10 mu M), the Na-v1.8 antagonist A-803467, or a specific Na-v1.8 antibody. Veratridine elicited similar percentage increases in progressive motility in sperm cells maintained in Ca2+-containing or Ca2+-free solution and did not induce hyperactivation or the acrosome reaction. Veratridine caused a rise in sperm intracellular Na+, [Na+](i), and the sustained phase of the response was inhibited in the presence of A-803467. These results verify that the Na+ channel Na-v1.8 is present in human sperm cells and demonstrate that this channel participates in the regulation of sperm function.This work was financially supported by grants from Junta de Andalucia (P08-CVI-04185) and Ministerio de Economia y Competitividad (CTQ2011-25564), Spain, with joint financing by FEDER and FSE funds from the European Union. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

RKIP Regulates Differentiation-Related Features in Melanocytic Cells

Raf Kinase Inhibitor Protein (RKIP) has been extensively reported as an inhibitor of keysignaling pathways involved in the aggressive tumor phenotype and shows decreased expressionin several types of cancers. However, little is known about RKIP in melanoma or regarding its functionin normal cells. We examined the role of RKIP in both primary melanocytes and malignant melanomacells and evaluated its diagnostic and prognostic value. IHC analysis revealed a significantly higherexpression of RKIP in nevi compared with early-stage (stage I–II, AJCC 8th) melanoma biopsies.Proliferation, wound healing, and collagen-coated transwell assays uncovered the implication ofRKIP on the motility but not on the proliferative capacity of melanoma cells as RKIP protein levelswere inversely correlated with the migration capacity of both primary and metastatic melanoma cellsbut did not alter other parameters. As shown by RNA sequencing, endogenous RKIP knockdownin primary melanocytes triggered the deregulation of cellular differentiation-related processes,including genes (i.e., ZEB1, THY-1) closely related to the EMT. Interestingly, NANOG was identifiedas a putative transcriptional regulator of many of the deregulated genes, and RKIP was able todecrease the activation of the NANOG promoter. As a whole, our data support the utility of RKIPas a diagnostic marker for early-stage melanomas. In addition, these findings indicate its participationin the maintenance of a differentiated state of melanocytic cells by modulating genes intimately linkedto the cellular motility and explain the progressive decrease of RKIP often described in tumors.This project was supported by grants from the Basque Government (KK2016-036 and KK2017-041 toM.D.B.), UPV/EHU (GIU17/066 to M.D.B.), H2020-ESCEL JTI (15/01 to M.D.B.) and MINECO (PCIN-2015-241 toM.D.B.). CP holds a predoctoral fellowship from the Basque Governmen