Molecular Human Reproduction

BackgroundMitochondrial dysfunction is a leading contributor to the decline in oocyte quality associated with maternal aging. Prior investigations of mitochondrial function in the ovarian follicle have largely treated the mitochondrial pool as a homogeneous population, reporting aggregate values that may obscure biologically meaningful differences between distinct mitochondrial subpopulations. The present study addresses this limitation by characterizing mitochondrial subpopulation dynamics in oocytes and cumulus granulosa cells at single-organelle resolution using fluorescence-activated mitochondria sorting (FAMS). ResultsAnalysis of the aggregate mitochondrial population in mouse oocytes revealed no significant age-associated differences in mitochondrial DNA copy number or membrane potential, a result that would previously have been interpreted as evidence of minimal age-related mitochondrial change. Subpopulation analysis revealed this conclusion to be incomplete: aged oocytes showed significantly elevated mitochondrial DNA copy number specifically within the high membrane potential and small mitochondrial subpopulations, with no significant differences in the low membrane potential or large subpopulations. NMN supplementation normalized mitochondrial DNA copy number in the high membrane potential and small subpopulations toward young levels while producing an opposing effect in large mitochondria, demonstrating subpopulation-specific rather than uniform rejuvenation. In cumulus cells, significant age-associated changes were detectable at the aggregate level, including a reduction in mitochondrial DNA copy number and an elevation in membrane potential, and subpopulation analysis further resolved these findings. The age-associated reduction in cumulus cell mitochondrial DNA copy number was driven predominantly by the high membrane potential subpopulation. NMN supplementation exerted opposing effects on small and large cumulus cell mitochondrial subpopulations, increasing mitochondrial DNA copy number above both young and aged levels in small mitochondria while further reducing it below aged levels in large mitochondria. ConclusionsViewing the mitochondrial pool as a heterogeneous mixture of functionally distinct subpopulations rather than a uniform population reveals age-associated alterations in oocytes and cumulus cells that are undetectable by aggregate analysis. NMN supplementation exerts subpopulation-specific effects in both cell types, identifying specific mitochondrial subtypes as more precise targets for future mechanistic investigation of age-associated infertility than the mitochondrial pool considered in aggregate.

Non-obstructive azoospermia (NOA) is the absence of sperm in the ejaculate due to spermatogenic failure. Fifty percent of NOA cases are unexplained but may arise from unidentified genetic mutations. Variants in TEX11 have been identified in men with NOA; and Tex11 knockout in mice causes NOA. Here we attempt to validate three TEX11 variants discovered in NOA patients by knocking them into the orthologous region of the mouse genome using CRISPR/Cas9 gene editing. Compared to wild type (144.2 {+/-} 9.87 mg; 1.7 {+/-} 0.5 million sperm/cauda epididymis 4.8 {+/-} 1.3 pups/breeding), Tex11D mice (frameshift mutation) had reduced testis weight (28.33 {+/-} 1.16 mg); no sperm in the epididymis; and were infertile with a maturation arrest testicular phenotype. We did not observe any spermatogenesis or fertility defects Tex11A mice (missense mutation). Tex11L mice had reduced testis weight (87.5 {+/-} 14.79 mg) and epididymal sperm counts (0.33{+/-}0.13 million/cauda epididymis) but an incompletely penetrant infertility phenotype (5.4 {+/-} 1.13 pups/breeding) with one third of mice being infertile. Infertile Tex11L mice also had a distinct epididymal phenotype with reduced sperm density in the caput and no sperm in the cauda, which was filled with amorphous material.

Study questionWhich proteins underpin oocyte developmental competence, as modelled by oocytes of variable competence matured in vivo, or matured in vitro under different conditions (capacitation in vitro maturation (CAPA) or standard in vitro maturation (IVM))? Summary answerSignificant differences in the global proteome were observed in both oocytes and their corresponding cumulus cells depending on the mode of oocyte maturation, with key variations in eukaryotic translation, autophagy and endocytosis pathways within oocytes, and changes in reactive oxygen species detoxification and serine biosynthesis in cumulus cells. What is known alreadyWithin the ovarian follicle, mammalian oocytes must acquire the necessary molecular machinery to support successful fertilisation and embryonic development. Close contact with the surrounding cumulus cells ensures coordinated nuclear and cytoplasmic maturation of the oocyte, along with the accumulation of proteins stored within the oocyte in cytoplasmic lattices and endo-lysosomal vesicular assemblies. Study design, size, durationThis basic science study utilised a mouse model to assess proteomic changes across three oocyte competence models. Key proteins identified in mouse oocytes were also assessed in discarded immature human germinal vesicle (GV) oocytes and MII oocytes following rescue-IVM. Three oocyte maturation methods were tested: i) in vivo maturation, (ii) CAPA and (iii) standard IVM. In vivo maturation served as a positive control group, whereby metaphase II (MII) mature oocytes were collected from mice stimulated with pregnant mare serum gonadotropin (PMSG) and triggered with human chorionic gonadotropin (hCG), simulating full ovarian stimulation. For the in vitro maturation groups, immature cumulus oocyte complexes (COCs) were collected from mildly stimulated (23 hr PMSG) mice. For the standard IVM group, immature COCs were matured in media containing amphiregulin and epiregulin for 18 hours. For the CAPA group, COCs were held for 24 hours in pre-IVM conditions in the presence of c-type natriuretic peptide (CNP), oestradiol, insulin and follicle stimulating hormone (FSH), and then matured via IVM in media containing FSH, amphiregulin and epiregulin. Four biological replicates were performed for mouse proteomics experiments, three biological replicates performed for mouse immunocytochemistry experiments and six replicates were performed for embryology experiments. Participants/materials, settings, methodsFour to six-week-old C57BL/6JAusb mice were used for all mouse experiments. Embryology outcomes were used to confirm the variation in oocyte developmental competence between the three maturation groups. For the in vivo, CAPA and IVM groups, mature MII COCs were collected and separated into oocytes and cumulus cells. Oocytes and cumulus cells were subjected to mass spectrometry and bioinformatic analysis was performed using Proteome Discoverer and Ingenuity Pathway Analysis, with data validated by immunofluorescence. To assess conservation of proteins in human oocytes, 49 oocytes were collected from 36 patients following assisted reproduction technology (ART) cycles and subject to immunofluorescence. Rescue-IVM was also performed with half of the human oocyte cohort to obtain MII oocytes. Main results and the role of chanceProteomic profiling identified around 1600 proteins in mouse oocytes and 3100 in mouse cumulus cells across all three treatment groups (at least 2 peptides per protein). Differential expression analysis and pattern analysis collectively revealed a signature of proteins that were consistently differentially expressed between in vivo and in vitro oocyte maturation systems (log2FC of {+/-} 1 and a p-value [≤] 0.05). These subsets of proteins were mapped to biological processes including eukaryotic translation, autophagy and endocytosis pathways within oocytes. Orthogonal validation of clathrin, ribosomal protein L24 and eukaryotic initiation factor 2A supported the proteomic findings and expression was conserved in human oocytes. Changes in reactive oxygen species detoxification and serine biosynthesis were observed in mouse cumulus cells, with fluorescence intensity changes in ferredoxin-1 and phosphoglycerate dehydrogenase supporting the dysregulation of cumulus cell processes during in vitro maturation. Large scale dataThe mass spectrometry data are available via ProteomeXchange with identifier PXD073269. Limitations, reasons for cautionThe foundational mechanisms of oocyte developmental competence remain elusive, particularly in humans where MII oocytes are heterogenous in quality within the same stimulation cycle and patient. In this study, C57Bl6/J mice were used as the model species, allowing precise control over differing models of oocyte quality and capacity to analyse large numbers of oocytes. However, care is required when interpreting the significance of these findings in mice to mechanisms regulating human oocyte quality. Nonetheless, the in vivo stimulation and both IVM protocols used in this study are clinically relevant and developmentally matched. This study has also not addressed oocyte developmental competence in gonadotropin-free IVM oocytes, which is now a clinical reality. Wider implications of the findingsThis study confirms that mouse oocytes, matured in vitro in two clinically relevant systems, show reduced developmental competence when compared to in vivo matured oocytes. Through examination of the global proteome in oocytes, molecular pathways including eukaryotic translation, autophagy and endocytosis were dysregulated in in vitro oocytes. Recent findings have revealed the critical role of these pathways to developmental competence in the context of in vivo development. In cumulus cells, changes in reactive oxygen species detoxification and serine biosynthesis were observed, adding to the extensive knowledge around metabolic activity in cumulus cells as a critical facet of oocyte quality. Combined, this data suggests that the necessary processes of protein storage and degradation in oocytes and metabolism in cumulus cells constitute important components of oocyte quality. These processes appear suboptimal in current IVM systems, providing a future research direction to optimise IVM protocols with consideration to these protein pathways. Study funding/competing interestsThis study was funded by a National Health and Medical Research Council Investigator Fellowship (APP1023210) awarded to R.B.G. and by a gift from Open Philanthropy. The following competing interests are declared: R.B.G.is a consultant to Dioseve Inc.. L.E.W is a co-founder, shareholder, director and advisor of Jumpstart Fertility Inc.. L.E.W. is also an advisor and shareholder in EdenRoc Sciences, the parent company of Metro Biotech NSW and Metro Biotech, and in Life Biosciences LLC and its daughter companies. His UNSW Industry Scientia position is partly funded by Proto Axiom. All other authors have no competing interests to disclose.

BACKGROUNDDuring spermiogenesis, histones are exchanged by protamines (PRMs) in spermatids, which results in DNA hypercondensation and protection. Rodents and primates express two PRMs (PRM1 and PRM2) in a species-specific ratio. Maintaining this ratio is necessary for functional chromatin reorganization and alteration is associated with sub- or infertility in mice and humans. Prm1 and Prm2 deficient mice are infertile, while Prm1+/- males are subfertile showing a severely altered PRM ratio. Prm2+/- males are fertile and display a protamine ratio comparable to WT. OBJECTIVESHere, we addressed the question whether loss of one allele of Prm1 and one allele of Prm2 affects fertility. MATERIAL AND METHODSDouble heterozygous (dHET) mice lacking one allele of Prm1 and one allele of Prm2 were generated and analyzed RESULTSdHET males were infertile with sperm showing retention of histones and TNPs, high levels of PRM2 precursor and decreased levels of mature PRM2. In mature sperm the PRM ratio and the total PRM content was not altered. However, CMA3 staining revealed incomplete protamination and sperm nuclei appeared more rounded and slightly bigger, suggesting impaired DNA-hypercondensation. In dHET sperm, DNA degradation was apparent, but to a lower level compared to sperm from Prm1 and Prm2 deficient males. Increased 8-OHdG levels suggested oxidative stress in the epididymis of dHET mice. However, a fraction of dHET sperm were capable of fertilization, with embryonic development up to 8-cell stage. DISCUSSION AND CONCLUSIONThese results suggest, that male factor infertility might not be reliably detected by measuring PRM1/PRM2 ratio but rather by determining the level of protamination by e.g. CMA3 analysis and pre-PRM2 retention.

IntroductionNon-obstructive azoospermia (NOA) represents the most severe form of male infertility. Current clinical tools have limited ability to predict sperm production or guide surgical sperm retrieval. Conventional B-mode ultrasound provides qualitative grayscale images and cannot characterize testicular microstructure relevant to spermatogenesis. Quantitative ultrasound (QUS) provides objective parameters from raw radiofrequency data, which quantitatively measure tissue heterogeneity. We hypothesize that men with spermatogenesis will have different QUS features compared to men without spermatogenesis (measured by total motile count, TMC, on semen analysis), with the goal of identifying imaging biomarkers for prognosis and intraoperative guidance. MethodsWe prospectively analyzed men presenting for infertility evaluation who underwent high-frequency ultrasound imaging and semen analysis. Imaging was performed using a 36-MHz transducer with fixed acquisition parameters. Ninety-two QUS features were extracted from manually annotated testicular regions of interest, including Nakagami distribution parameters (m, {omega}, k), envelope statistics, and texture features. Univariate associations between each QUS feature and TMC were assessed using Spearman correlation with Bonferroni correction. Top-performing features were evaluated using logistic regression and receiver operating characteristic (ROC) analysis to discriminate sperm presence or absence (TMC>0 vs TMC=0). ResultsThirty-seven men (18 azoospermic, 19 with sperm present in the ejaculate) contributed 135 regions of interest. Seventeen of 92 QUS features significantly correlated with TMC after correction. The coefficient of variation of the Nakagami k-factor within the superficial testicular parenchyma (K_Zone1_Cv) demonstrated the strongest correlation ({rho}=0.51, corrected p<0.001), suggesting that greater spatial heterogeneity in the superficial parenchyma was associated with higher sperm counts. K_Zone1_Cv discriminated sperm presence with an AUC of 0.77 (95% CI 0.60-0.92), sensitivity 73.7%, and specificity 83.3%. QUS features with the highest univariate association were highly intercorrelated, suggesting a shared biological signal. ConclusionQuantitative ultrasound-derived measures of testicular microstructure heterogeneity correlate with sperm production and demonstrate moderate discrimination of sperm presence. These findings suggest QUS may provide a non-invasive imaging biomarker of spermatogenesis. Study findings warrant further assessment and validation in male infertility for sperm retrieval prognosis and the potential for intra-operative surgical guidance.

In vitro fertilization (IVF) is key for genetic improvement programs in bovine. However, embryos produced through IVF have lower developmental competence than those produced under in vivo conditions. Conventional sperm preparation for IVF typically relies on heparin for sperm capacitation but fails to replicate the finely tuned molecular environment of the oviduct, resulting in compromised embryonic competence. Here, we evaluated the effect of HyperBull, a novel capacitation technology, on bovine IVF outcomes using unsorted cryopreserved semen. In a split-sample design, 528 cumulus-oocyte complexes were co-incubated with either control or HyperBull capacitated spermatozoa from the same bull. While overall blastocyst rates were not significantly different between groups (34.21% HyperBull vs. 28.63% control, p=0.148), the proportion of hatched embryos was significantly higher in the HyperBull group (15.82% vs. 9.13%, p=0.016). These findings suggest that modulating capacitation signals prior to insemination enhances embryonic developmental competence, thereby improving readiness for implantation. HyperBull may thus represent a valuable tool to increase the efficiency of IVF programs.

BackgroundDDX53 (DEAD-box helicase 53, known also as CAGE) is an intronless gene on the X chromosome, which expression shows strong testis specificity. It belongs to the group of cancer-testis (CT) antigens, with most studies to date focusing on its role in cancer, but the precise biological function of DDX53 remains unclear. Previous reports identifying rare DDX53 variants in infertile men provided the rationale for investigating the role of DDX53 in the context of human spermatogenesis. By using the human seminoma cell line (TCam-2) as an in vitro male germline model, we aimed to investigate the function and molecular targets of DDX53. MethodsIn our study, we used transcriptomic and proteomic approaches (RNA sequencing (RNA-seq), enhanced crosslinking and immunoprecipitation (eCLIP), and Co-immunoprecipitation coupled with Mass Spectrometry (Co-IP-MS)) to investigate the role of DDX53 in the context of human spermatogenesis. By using modified TCam-2 cells to express either DDX53-FLAG or GFP-FLAG, we identified regulated genes, RNA targets, and potential protein interactors of DDX53. In addition, we employed Western Blot, RT-qPCR, immunostaining, and confocal microscopy to gain deeper insight into the DDX53 protein. ResultsOur RNA-seq and eCLIP data provide evidence that DDX53 regulates gene expression changes and directly interacts with a broad spectrum of RNA transcripts. Moreover, for the first time, we described RNAs and protein interactors of DDX53 in the context of spermatogenesis. Subcellular localization analysis by confocal microscopy indicated a predominantly cytoplasmic distribution of DDX53, with partial nuclear presence in TCam-2 cells. We also identified DDX53-positive structures that may correspond to germ granule-like assemblies, although their precise nature remains to be determined. Additionally, we confirmed DDX53 presence in human testis using a specific, commercially available anti-DDX53 antibody. ConclusionsThis studys data indicate that DDX53 protein acts as a regulator of RNA metabolism in human cells. Collectively, we show that it participates in transcriptome regulation (including splicing) in male germ cells and exhibits transcriptome-wide RNA interactions, but its wider biological role remains to be clarified.

ObjectiveTo determine whether quantitative ultrasound (QUS), which characterizes tissue microstructure using radiofrequency data, can identify regional heterogeneity within seminiferous tubules that corresponds to localized spermatogenesis in men with non-obstructive azoospermia (NOA). DesignTwo-cohort study using a biological extremes cohort to establish plausibility of a QUS biomarker, followed by an independent NOA-biopsy cohort with site-matched imaging and tissue sampling. SettingAcademic male fertility referral center. PatientsThe biological extremes cohort included fertile men with presumed intact spermatogenesis (n=15) and men with NOA and subsequent negative microdissection testicular sperm extraction (mTESE; n=10). The NOA-biopsy cohort consisted of 27 men with NOA undergoing site-matched testicular biopsy via testicular sperm aspiration (TESA) or testicular sperm extraction (TESE), yielding 12 sperm-positive and 36 sperm-negative biopsy sites. InterventionsHigh-frequency testicular ultrasound (36 MHz) with acquisition of raw radiofrequency data, allowing objective, quantitative analysis of tissue scattering patterns beyond conventional grayscale imaging. Regions of interest were manually annotated and, in the NOA-biopsy cohort, spatially matched to biopsy locations. Main Outcome MeasuresAssociation between sperm presence at biopsy sites and a pre-specified QUS measure of local tissue heterogeneity: the 75th percentile of a sliding window coefficient of variation map of the Nakagami k-factor within the superficial testicular parenchyma (K_Zone1_CV). This metric reflects the upper range of local variability in ultrasound backscatter, which is influenced by the underlying organization of seminiferous tubules. ResultsIn the biological extremes cohort, K_Zone1_CV distinguished fertile controls (median 1.79, IQR 1.64-1.85) from NOA men with globally negative mTESE (median 1.51, IQR 1.42-1.58; P < 0.001), with an area under the receiver operating characteristic curve (AUC) of 0.91 (95% CI 0.79-1.00). In the independent NOA-biopsy cohort, K_Zone1_CV discriminated sperm-positive from sperm-negative biopsy sites with an AUC of 0.93 (95% CI 0.85-0.99). At a threshold of 1.60, sensitivity was 100%, specificity was 86.1%, positive predictive value was 70.6%, and negative predictive value was 100%. Serum hormone levels, testicular volumes, and biopsy technique did not differ significantly between groups. ConclusionsRegional testicular tissue heterogeneity measured by quantitative ultrasound is associated with localized spermatogenesis in men with NOA. At the selected threshold, no sperm-positive biopsy site was misclassified as negative. These findings support the hypothesis that QUS can noninvasively detect the focal seminiferous tubule heterogeneity that predicts sperm retrieval success. This imaging approach could inform future image-guided sperm retrieval strategies. Further validation in larger cohorts and assessment of intra-patient variability are needed.

The X chromosome (chrX) is the eighth largest human chromosome, harbouring an estimated total of 839 protein-coding genes. Historically, the chrX has been described as enriched for genes related to brain development, sexual differentiation and reproduction, earning the epithet of "smart and sexy chromosome". Many studies have confirmed that the chrX is indeed "smart", including a recent systematic analysis of human chrX genes which found an enrichment in genes relevant to brain functions. However, it is less clear whether the chrX being "sexy" still holds true. Here we reviewed the origins of this idea and we evaluated human X-linked genes in terms of their expression across several tissues, their annotated functions and their association with monogenic disorders related to sexual differentiation and reproduction (SDR). We found that sex-specific tissues show higher expression levels from chrX genes than from autosomal genes except in testis, but that X-linked genes are significantly enriched among the most highly expressed genes in testis, specifically within spermatogonia and Sertoli cells. Yet, we found no evidence for an enrichment of genes on the X with annotated functions related to male or female SDR. When analysing SDR-related monogenic disorders, we found a significant enrichment of genes on chrX associated with clinical terms related to male SDR but not with clinical terms related to female or general SDR. Overall, our results support the notion of a somewhat "sexy" X chromosome, shaped by X-linked expression patterns and clinical associations rather than current annotated gene functions.

STUDY QUESTION[Do structural genomic variants, that can be identified by using optical genome mapping, contribute to male infertility?] SUMMARY ANSWER[By using optical genome mapping we can identify several types of structural variants, both known and new, that may contribute to male infertility.] WHAT IS KNOWN ALREADY[Traditional approaches such as karyotyping, CFTR and chromosome Y microdeletion testing are successful in explaining clinical findings in [~]30% of MI patients, leaving the rest without a genetic diagnosis. Recent research suggests at least 265 genes may play a role in male fertility. While the assessment of the roles of copy number variants and single nucleotide variants in monogenic forms of disease in these genes is underway, much less is known about structural variants.] STUDY DESIGN, SIZE, DURATION[We performed a longitudinal case/control study on a total of 220 individuals; 88 patients with male infertility, negative for cytogenetic abnormalities using karyotyping, and molecular testing for chrY microdeletions, and CFTR gene variants, and 132 healthy male individuals that underwent optical genomic mapping for other reasons. Exclusion criteria for the control cohort were low-sperm quality and/or inclusion in IVF procedures. The study was approved by the National Medical Ethics Committee of the Republic of Slovenia (reference number: 0120-213/2022/6). Optical genome mapping was performed from an aliquot of whole blood collected for routine testing purposes at the Clinical Institute of Genomic Medicine (CIGM), UMC Ljubljana from January 2023 to November 2024.] PARTICIPANTS/MATERIALS, SETTING, METHODS[We examined structural variants in 220 participants by using optical genome mapping, which was performed with DLE-1 SP-G2 chemistry and the Saphyr instrument. The de novo assembly and Variant Annotation Pipeline were executed on Bionano Solve3.7_20221013_25 while reporting and direct visualization of structural variants was done on Bionano Access 1.7.2. All obtained variants were filtered using the Bionano Access software and in-house generated gene/regions of interest panel bed files. The first filter was applied to include variants below a population frequency of 10%, and overlapping the regions of interest. Subsequently, all variants occurring with frequency 0% in the internal manufacturer variant dataset were manually evaluated for possible involvement of the overlapping genes or regions in biological processes involved in MI. The male infertility cohort also underwent research whole exome analyses as previously reported. All results of optical genomic mapping were confirmed by an appropriate alternative method where available.] MAIN RESULTS AND THE ROLE OF CHANCE[We show that the overall number of structural variants in MI patients does not differ from that of healthy individuals. By looking in detail at genes and regions associated with MI, we identified 21 rare variants absent from controls in 25.0 % of MI patients, of which five were likely causative, and two would be missed by using traditional approaches. These variants include inversions, duplications, amplifications, deletions (e.g. SPAG1), and insertions/expansions (e.g. DMPK), that were validated using additional methods. While the remaining SV cannot be currently classified as pathogenic according to existing criteria, they open a new avenue in genetic research of MI. LARGE SCALE DATA[Variants reported in this study were deposited into ClinVar under accession numbers SUB15650956 (https://www.ncbi.nlm.nih.gov/clinvar/)] LIMITATIONS, REASONS FOR CAUTION[Technical limitations of optical genome mapping include the lack of DLE-1 labelling of centromeric and telomeric regions, the inability to detect Robertsonian translocations, the unclear exact location of smaller structural variants located between the DLE-1 labels, and unclear boundaries in case of their location in segmentally duplicated regions (this limitation is shared with other methods). The ACGM criteria of rarity are also hard to apply, as the fertility status of the individuals in healthy population databases such as GnomAD and DGV is unknown. Similarly, gene-associated phenotype and the proposed inheritance model both need to be considered as parts of the ACMG criteria, but for many candidate genes associated with MI, no model of inheritance has yet been proposed.] WIDER IMPLICATIONS OF THE FINDINGS[Currently, with the established diagnostic approaches we are able to resolve [~]30% of male infertility cases, with [~]70% of patients remaining undiagnosed. The significance of our work is in showing that rare structural variants can be identified in MI, by using optical genome mapping, opening new avenues of research of the genetics of this important contributor to human fertility.] STUDY FUNDING/COMPETING INTEREST(S)[All authors declare having no conflict of interest in regard to this research. This work was funded by the Slovenian Research and Innovation Agency (ARIS) Programme grant P3-0326: Gynecology and Reproduction: Genomics for personalized medicine] Lay summaryMale infertility affects about 5% of adult males and has complex causes, including genetic ones, such as mutations in the CFTR gene, small deletions on chromosome Y, and balanced translocations, but currently we can only find a genetic cause in [~]30% of patients. This means [~]70% of cases remain undiagnosed but potentially, they too may have a yet unknown genetic cause. Indeed, so far research has shown at least 265 genes have been proposed to play a role in male fertility. In these genes, there has so far been limited research of single nucleotide variants and of copy number variants, but many structural variants are not visible using commonly used methods in clinical genetic testing. Therefore, apart from chromosome Y microdeletions and chromosomal numerical and structural anomalies, such as balanced translocations, the role of smaller structural variants in male infertility is unknown, but based from what we know from other diseases, they also may play a role in male infertility. Optical genome mapping is a novel method for the detection of structural variants, such as balanced and unbalanced translocations, insertions, duplications, deletions, and complex structural rearrangements in a wide range of sizes. By using optical genome mapping to test a cohort of 88 infertile men and 132 healthy controls, we aimed to provide the first insights into the range of SV that may be associated with MI. We found, by using optical genome mapping, the overall number of structural variants in MI patients not to be significantly different to the control group. However, by looking at genes and regions associated with MI, we can find rare structural variants that are absent from controls in 25.0% of MI patients. These variants include inversions, duplications, amplifications, deletions (e.g. deletion in SPAG1), and insertions/expansions (e.g. in DMPK), that were validated using additional methods. Five of these variants (5.6%) were likely causative, and two would be missed by traditional approaches. While the remaining SV cannot be currently classified as pathogenic according to existing criteria, they open a new avenue in genetic research of MI.

Cannabis (marijuana) is the most widely used recreational drug in the USA accounting for about 62 million users in 2024. Among cannabis users, 26% are of prime reproductive age (18-25 years). Delta-9 tetrahydrocannabinol (THC) is the principal psychoactive component of cannabis and has been detected in human seminal fluids. Although abundant evidence indicates adverse effects of THC exposure on spermatogenesis in different species, acute effects of THC on postejaculatory sperm including fertilization potential and subsequent carryover effects on embryo development are largely unknown. The present study was designed to provide missing information on structural and mechanistic effects of THC exposure to postejaculatory sperm function by evaluating sperm indices often overlooked or masked during clinical evaluation. A bovine embryo continuum model was employed to determine effects of THC on sperm structure, kinematics, bioenergetics, and binding mechanisms. Effects of THC on the sperm genomic and epigenomic landscape were determined, complemented by paternal carry over effects on embryo development as a human translational model to elucidate paternal effects on future development, and to mirror sperm exposure during transport within the female reproductive tract. Cryopreserved bovine sperm from three bulls were independently exposed to physiologically relevant concentrations of THC (0 and 32nM, n = 2 individual replicates/bull) for 24 h under non-capacitating conditions at 25{degrees}C followed by quantification of sperm kinematics at 37{degrees}C. Samples of THC-exposed sperm and vehicle-control (0.1% DMSO) were collected in replicate following immediate addition of THC (0 h) and again at 24 h. DNA damage, acrosome integrity, bioenergetics, changes to DNA methylation and embryo development were quantified. Data were analyzed by logistic regression with a generalized linear mixed effect model. Computer-assisted sperm assessment revealed a reduction in progressive motility of THC-exposed sperm after 24 h while other parameters were not affected. Acrosome integrity as determined by flowcytometric analysis with FITC-PSA was severely compromised in THC-exposed sperm (P [&le;] 0.05), despite no detectable difference in capacitation status using merocyanine staining. Similarly, DNA integrity as determined by TUNEL assay was significantly impaired after 24 h of THC exposure (P [&le;] 0.05). Mechanistic effects of THC were explored through characterization of the transmembrane G-protein coupled cannabinoid 1 receptor (CB1). CB1 is expressed in the post-acrosomal region and its abundance decreased as compared to unexposed sperm. Alterations to the methylation landscape of sperm were then determined after 24 h of THC exposure through whole-genome Enzymatic Methyl Sequencing. PCA analysis indicated that sperm from different males formed distinct clusters, implying individual differences among bulls, while the effects of THC exposure produced tighter clusters. Paternal carryover effects on embryos derived by in vitro fertilization from THC exposed sperm had reduced 2-cell cleavage, 8-16 cell morula development, and reduced blastocyst development compared to unexposed sperm (46% vs. 33%). In conclusion, post-ejaculatory mammalian sperm exposure to THC compromises acrosome integrity, induces DNA damage, changes the sperm methylome, and reduces developmental potential. Collectively, these data implicate new considerations for recreational and clinical use of cannabis that impact cellular and molecular mechanisms important for sperm function with detrimental consequences for gamete interaction and embryo development.

STUDY QUESTIONAre pathogenic variants in Homeodomain-interacting protein kinase (HIPK4) associated with sperm head abnormalities causing male infertility? SUMMARY ANSWERHIPK4 is a novel candidate gene associated with sperm head defects and human male infertility. WHAT IS KNOWN ALREADYNumerous genes causing male infertility due to Multiple Morphological Abnormalities of the sperm flagella (MMAF) have been described but the genetic basis of sperm head defects is less well understood. STUDY DESIGN, SIZE, DURATIONFour infertile brothers displaying varying degrees of quantitatively and/or qualitatively impaired spermatogenesis, their parents, and their fertile brother were included in the study. Further, the Male Reproductive Genomics (MERGE) cohort comprising exome/genome sequencing data of >3,300 men was queried. PARTICIPANTS/MATERIALS, SETTING, METHODSWe performed exome sequencing in all five brothers and their parents. To characterise the sperm phenotype, standard semen analysis, immunofluorescence staining, and transmission-electron microscopy (TEM) were carried out. Further, we evaluated the impact of the HIPK4 variant in cell culture experiments using HEK293T cells. MAIN RESULTS AND THE ROLE OF CHANCEAnalysing the exome data, we could not identify a common genetic cause in all four affected brothers. However, one of the affected brothers was compound heterozygous for two loss-of-function variants in DNAH17 (c.1076_1077dup p.(Lys360*) and c.7752+2T>A p.?) associated with markedly reduced sperm motility and MMAF. The variants pathogenicity was further validated by TEM of flagellar cross-sections revealing an outer dynein arm defect and axonemal disruption. On the contrary, his three infertile brothers were homozygous for the start-loss variant c.1A>G in HIPK4. This gene is expressed during spermiogenesis and is reportedly involved in sperm head shaping in mice. Heterologous expression of (partial) HIPK4 variant cDNA elucidated the alternative use of an in frame start codon located 35 amino acids downstream, resulting in an N-terminally truncated protein p.(Met1_Glu35del). The truncated HIPK4 protein lacks parts of its kinase domain and shows reduced protein stability. In line with published mouse models, all three brothers displayed 100% abnormal sperm head morphology with variable defects. Importantly, one brother affected by HIPK4 variants fathered a child after successful intracytoplasmic sperm injection demonstrating that it is a treatment option for HIPK4-related teratozoospermia. No further men from the MERGE cohort were affected by biallelic HIPK4 variants. Taken together, HIPK4 is an autosomal-recessive candidate gene associated with sperm head defects and male infertility. LARGE SCALE DATAThe reported variants in DNAH17 and HIPK4 were submitted to ClinVar. LIMITATIONS, REASONS FOR CAUTIONIndependent replication is required to assess the phenotypic spectrum and the reproductive outcome associated with biallelic HIPK4 variants and to formally establish the gene-disease relationship for male infertility. WIDER IMPLICATIONS OF THE FINDINGSThis study raises awareness of the significant genetic heterogeneity of male infertility. The described family highlights that distinct genetic causes may underlie a seemingly similar phenotype. Exome sequencing of families is helpful to efficiently disentangle individual causes among affected family members. STUDY FUNDING/COMPETING INTEREST(S)N.N., J.R., H.O., S.L., C.F., and F.T. were supported by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) within the Clinical Research Unit Male Germ Cells (CRU326, project number 329621271). R.T.W., N.N., J.R., H.O., and F.T. were supported by the Federal Ministry of Research, Technology and Space (BMFTR) as part of the project ReproTrack.MS (grant 01GR2303). S.A.K. was supported by the DFG Clinician Scientist programme CareerS Munster (project number 493624047). A.S.G. was supported by the Medical Faculty Munster via an Innovative Medical Research (IMF) grant (GA-122104).

Boar semen contains spermatozoa and seminal plasma (SP) that carries extracellular vesicles (EVs) among other components. However, artificial insemination (AI) doses produced by AI companies are highly diluted based solely on sperm concentration. The aim of this study was to evaluate the integrity of EVs isolated from AI doses, characterize the protein and miRNA content from high-fertility (HF) and reduced-fertility (RF) boars, and evaluate their functional impact on spermatozoa after dilution by a coincubation up to 24 hours at 38 {degrees}C. Proteomics identified 108 differentially expressed proteins between HF and RF EVs (97 upregulated in HF, 11 in RF), and transcriptomics revealed 80 differentially expressed miRNAs (DEMs) in EVs, 52 in SP, and 3 in spermatozoa, showing inverse expression in various shared DEMs between fertility rates, suggesting compartment-specific regulation. Functional coincubation demonstrated that EVs remain biologically active after dilution. HF EVs improved sperm quality parameters and reduced oxidative stress, while RF EVs increased total and progressive motility. Overall, our findings show that EVs from AI doses retain structural integrity, carry fertility-associated protein and miRNA signatures, and functionally modulate sperm quality in vitro. These features highlight porcine EVs as promising biomarkers and potential tools to optimize reproductive performance in swine production.

BackgroundApproximately one-third of men having undergone gonadotoxic treatment in their childhood experience impaired testicular function for whom autologous transplantation of cryopreserved immature testicular tissue may represent the only opportunity to restore their fertility. Pre-clinical studies have demonstrated successful restoration of spermatogenesis following grafting of immature testicular tissue in various species, including non-human primates. In 2002, our institution pioneered with clinical testicular tissue banking for fertility preservation in boys and adolescents. Over time, this strategy has been increasingly implemented by numerous fertility centres worldwide for patients at high risk of treatment-induced sterility. Here, we report the first human case of autologous transplantation of frozen-thawed immature testicular tissue. PatientIn 2008, testicular tissue was cryopreserved from a pre-pubertal boy diagnosed with sickle cell disease. The procedure was performed after a three-year hydroxyurea treatment and prior to receiving conditioning therapy with busulfan and cyclophosphamide for haematopoietic stem cell transplantation. One testis was surgically removed, sectioned into small fragments, and cryopreserved. Histological analysis confirmed preserved tubular architecture and the presence of spermatogonia. During the period from 2022 to 2024, the patient consistently presented with azoospermia. In December 2024, at the time of transplantation, two abnormal sperm cells were detected after enzymatic digestion. MethodEleven testicular tissue fragments (4-21 mm3) were thawed and autologously grafted to four intra-testicular and four subcutaneous scrotal sites. Over a one-year follow-up period, graft survival, vascularization, hormone profiles, and semen parameters were monitored. One year after transplantation, all grafts were surgically retrieved. ResultsPost-operative recovery was uneventful. No significant changes in endocrine or semen parameters were observed during follow-up. Whereas the intra-testicular grafts exhibited a compact parenchyma that was distinct from the looser surrounding adult parenchyma and remained readily identifiable as graft tissue, the scrotal grafts appeared more fibrotic. Enzymatic digestion of the grafts was required to recover spermatozoa, with one spermatozoon obtained from one of the four intra-testicular grafts. Histological evaluation revealed intact tubular architecture and maturation of somatic cells across all grafts. Spermatogonial stem cells, together with evidence of active spermatogenesis, were identified in two of the four intra-testicular grafts, whereas no germ cells were detected in the subcutaneous scrotal grafts. ConclusionThese findings demonstrate that human immature testicular tissue can survive long-term cryostorage, revascularize after transplantation and establish spermatogenesis in vivo. This study provides essential proof-of-concept for fertility restoration in individuals who banked testicular tissue before puberty. FundingThis study was supported by the Research Programme of FWO Vlaanderen (Research Foundation-Flanders; G0A6U25N) and VUB strategic research program (SRP89). Trial Registration: NCT05414045

Pregnancy results in profound physiological changes driven by dynamic and precisely programmed molecular processes. Maternal peripheral blood is generally the specimen of choice for studying these processes, as it is easily accessible and essential for many aspects of maintaining a healthy pregnancy. Here, we present a high-resolution atlas of the dynamic temporal changes in the transcriptome of maternal peripheral blood in healthy human pregnancy. We generated comprehensive RNA sequencing data in 802 weekly samples from 31 healthy pregnant women from the first trimester until after delivery. Using a strict discovery and replication setup, our longitudinal analysis of gene expression identified 720 genes with robust pregnancy-specific expression patterns. Using weighted graph correlation network analysis, we identified nine pregnancy-associated transcriptional modules that reveal a strong, coordinated enrichment of innate/neutrophil and antiviral immune programs, alongside changes in adaptive immunity (T cell differentiation and signaling), erythropoiesis and hemoglobin metabolism. Cell-type deconvolution revealed that these transcriptomic shifts were accompanied by increased relative neutrophil proportions and reduced naive CD4 and CD8 T cells in pregnancy. We provide a comprehensive characterization of dynamic changes across pregnancy, highlighting maternal blood as a key systemic regulator in healthy gestation. Together, our findings establish a reference atlas of healthy pregnancy, which can be used to identify dysregulated processes and mechanisms in women with pregnancy complications. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=168 SRC="FIGDIR/small/715300v1_ufig1.gif" ALT="Figure 1"> View larger version (34K): org.highwire.dtl.DTLVardef@2a4b28org.highwire.dtl.DTLVardef@ac49d9org.highwire.dtl.DTLVardef@12468c8org.highwire.dtl.DTLVardef@15b282f_HPS_FORMAT_FIGEXP M_FIG C_FIG O_LI720 genes showed robust pregnancy specific expression patterns. C_LIO_LICo-expression analysis clustered the genes into nine modules with distinct dynamics. C_LIO_LIEnrichment in pathways involved in innate and neutrophil-mediated immunity, antiviral responses, T cell differentiation and signaling, erythropoiesis and hemoglobin metabolism. C_LIO_LICell-type deconvolution showed increases in neutrophils and decreases in naive CD4 and CD8 T cells. C_LIO_LIThe atlas of detailed longitudinal transcriptional changes provides a baseline reference for healthy pregnancy. C_LIO_LIResults for all genes and protein-protein interaction networks are made available for interactive exploration. C_LI

BackgroundPolycystic ovary syndrome (PCOS) is a prevalent endocrine disorder and a leading cause of female infertility, with complex genetic, metabolic, and hormonal etiologies. Long non-coding RNAs (lncRNAs) have emerged as important regulators of diverse biological processes, yet their roles in PCOS remain underexplored. Here, we identified and characterized PCOS differentially expressed gene-associated lncRNAs (PDEGAL) with an integrative approach combining expression data, genetic association, and evolutionary analysis. MethodsThirty-three PCOS-associated protein-coding genes were obtained from our prior study, and all their nearby and overlapping lncRNAs were annotated. These candidates were analyzed using UCSC Genome Browser-mapped annotations and datasets, including NCBI RefSeq, GENCODE, GTEx, GWAS SNPs, and conservation, as well as the FANTOM5 cap analysis of gene expression (CAGE) promoter data, to assess their expression, regulatory potential, genetic variant overlaps, and evolutionary conservation. ResultsTwenty-three PDEGALs (18 antisense to, and 5 sharing bidirectional promoters with, known PCOS-associated protein-coding genes) were identified. 17 PDEGALs contained GWAS SNPs with statistically significant disease associations, 9 of which were associated with PCOS-related traits. 5 PDEGALs demonstrated expression in the KGN granulosa cell model of PCOS. Key gene structure element (KGSE) analysis revealed that most PDEGALs are primate-specific. Integrating four criteria--GTEx expression, GWAS SNPs, FANTOM promoterome, and KGSE conservation--highlighted HELLPAR as the only lncRNA fulfilling all four, while five others--PGR-AS1, MTOR-AS1, ENSG00000265179, ENSG00000256218, and LOC105377276--fulfilled three of the four criteria. ConclusionsWe have systematically identified candidate PCOS regulatory lncRNAs with convergent genetic, expression, and evolutionary evidence. These results provide a framework for functional validation and highlight lncRNAs as potential biomarkers and therapeutic targets in PCOS that function by regulating their nearby and overlapping protein-coding genes.

AimsTo explore exercise-induced fatigue (EIF)s effects on the male reproductive system and MXRA7s regulatory role herein. MethodsWe recruited EIF volunteers for semen/serum tests, established a mouse EIF model via weight-loaded swimming to assess epididymal segmental injury, and constructed pyroptosis models of PC-1/DC-2 cells. Public database transcriptomic analysis identified MXRA7 expression and enriched pathways in epididymitis; MXRA7s function was verified via its knockdown/overexpression in DC-2 cells. PKC-MXRA7 association was explored by phosphorylation assays and CO-IP, and sperm incubation experiments evaluated MXRA7s effect on sperm function. ResultsEIF impaired human sperm motility, reduced mouse sperm quality and induced epididymitis with segment-specific pyroptosis. MXRA7 expression differed in PC-1/DC-2 cells and correlated with pyroptosis; it was phosphorylated by PKC, inhibited the NF-{kappa}B pathway to alleviate inflammation, and mitigated pyroptosis-induced sperm motility damage. ConclusionEIF induces epididymal epithelial pyroptosis and epididymitis, and MXRA7 exerts a protective effect mainly in caudal epididymal cells by alleviating pyroptosis, thus reducing sperm quality damage.

Background: Male factor infertility is present in around 40% of couples utilising assisted reproductive technology (ART). However, it is unclear how specific causes of male infertility impact the chance of successful ART treatment, with most research either treating male infertility as single diagnostic group or being isolated smaller-scale studies focused on the treatment and outcomes of specific diagnoses. Objective: To study the impact of eleven specific aetiologies of male infertility on the chance of a clinical pregnancy in couples with known causes of male or female infertility following their first ART cycle. Material and methods: Population-based (initiated ART in Australia and New Zealand in 2020- 2022) cohort study assessing the impact of eleven male infertility diagnoses (idiopathic, Klinefelter syndrome, Y chromosome microdeletions, testis damage from cancer, testis damage from other causes, gonadotropin deficiency, congenital absence of the vas deferens/cystic fibrosis (CBAVD), other obstruction disorder, erectile dysfunction, and ejaculatory disorder) on the chance of a clinical pregnancy following a couple's first complete ART cycle (all fresh and frozen-thawed embryo transfers arising from one episode of ovarian stimulation). Adjusted risk ratios comparing a couples undergoing ART solely for treatment of male infertility with couples undergoing ART solely for treatment of tubal disease were calculated for the chance of a clinical pregnancy following a complete ART cycle and following an attempted fertilisation procedure. Results: A total of 39,053 couples were included, with male infertility present in 42.7% of cases, and the only cause of infertility in just under half of these cases. In more than three-quarters of male infertility cases the cause of infertility was unknown (idiopathic) or undiagnosed. Most couples undertaking ART for treatment of male infertility can expect similar success rates to couples seeking treatment for good prognosis female infertility diagnoses. However, those with Klinefelter syndrome and Y chromosome microdeletions had a 59.5% (aRR: 40.5% [95% CI: 16.9%-64.1%]) and 28.9% (aRR: 71.1% [95% CI: 45.5%-96.7%]) lower chance of a clinical pregnancy per initiated stimulation cycle compared to those with tubal disease as the only source of infertility. However, there was no difference once sperm was retrieved compared to other diagnoses tending to require surgical sperm retrieval, use frozen oocytes and necessitating ICSI. Discussion and Conclusion: In this population-based study most couples undergoing ART because of male infertility had similar success rates to those undergoing ART for treatment of female tubal disease, except for patients with Klinefelter syndrome and Y chromosome microdeletion who had approximately half and three-quarters the chance of a clinical pregnancy due to failed sperm retrieval/survival, but no difference (accounting for the use of surgical sperm, ICSI and potentially frozen oocytes) in outcomes once sperm were available. While these finding are reassuring for most men presenting to an ART clinic with male infertility, with more than three-quarters of male infertility cases reported as being idiopathic, there is an urgent need for greater research on the causes, diagnosis and implications of male infertility.

BackgroundUnderstanding the causes of the exceptional rate of evolution of the mammalian placenta is likely to aid the understanding of placental development and the aetiology of the human-specific pregnancy disorder pre-eclampsia (PE). As retroelements (REs) are often lineage-specific and known to be co-opted for placental functioning, here we consider the RE binding of GATA3 and DLX5, these transcription factors being dysregulated in PE, and their downstream consequences. MethodsMultiomics analyses identified the retroviral regulatory sequence LTR8B in the PSG gene array, as a contributor to expression diversification in the placenta. To characterize this genomic domain, we performed copy number variation analysis and whole-genome sequencing. Multiomics data was employed to identify loci that might act as an active chromatin loop boundary around the PSG region. CRISPR-Cas9 knockouts with aligned RNAseq and epigenetic mark data tested for trophoblast-specific cis-regulatory elements (CREs-enhancer and/or promoter sequences) of resulting loci. Functional assays were employed to characterize the phenotypic effects of a candidate locus. Structural analysis of PSG family members also identified an additional RE, MER65-int. RNA-seq and antibody staining was employed to consider polyadenylation and functional diversification. ResultsThe LTR8B CRE facilitates the binding of transcription factors (e.g., GATA3, DLX5, TFAP2A/C), resulting in a diversified PSG gene expression pattern within a primate-specific genomic region that exhibits high intraspecies variability. The LTR8B/PSG9 regulatory element influences other PSG family members. PSG9, unique among PSGs, produces both secreted and membrane-anchored isoforms, MER65-int providing alternative polyA signals, enabling the evolution of secreted PSG variants through the truncation of the ancestral CEACAM proteins transmembrane domain. The LTR8B/PSG9 locus regulates the differentiation of multinucleated trophoblasts (syncytialization) and, like chorionic gonadotropin and syncytin1, determines the identity of syncytiotrophoblasts. Notably, PSG9 is the most upregulated PSG in PE, with levels correlated with GATA3 and DLX5 levels. ConclusionsREs contribute to the structural and expression evolution of PSG genes, facilitating lineage-specific placental evolution. The LTR8B/PSG9 regulatory network plays a central role in syncytiotrophoblast differentiation. Given the association between DLX5/GATA3 dysregulation and elevated PSG9 levels, along with PSG9s expression in the first trimester, PSG9 shows potential as a predictive biomarker for PE.

The myometrium, the muscle layer of the uterus, undergoes profound phenotypic changes throughout pregnancy, labor, and postpartum, allowing for successful reproduction. Transcriptomic analysis of the murine myometrium revealed distinct gene expression signatures corresponding to these physiological stages, which reflect the dynamic remodeling processes occurring in the uterus during late gestation, term labor, and postpartum. These transcriptomic signatures at specific gestational points were accompanied by changes to the accessible chromatin landscape. Notably, increased chromatin accessibility was observed in the mouse myometrium at full term (gestational day 19) before the onset of active labor contractions. Accessible chromatin regions were bound by the transcription factor JUND, from the AP-1 family, and associated with progesterone receptor (PR) binding. Depletion of the progesterone receptor isoform B (PRB) from accessible chromatin at this prelabor stage implicates progesterone receptor isoform A (PRA) as a binding partner with JUND at prelabor and labor. During labor onset, accessible chromatin regions were associated with elevated production of enhancer RNAs and enriched in binding sites for transcription factors from the AP-1, SOX, and ETS families, implicating additional transcription factors in the labor process. Although PRB was strikingly absent from labor-associated accessible chromatin, it was found associated with histone H3 lysine 27 trimethylated (H3K27me3) repressed regions in late gestation and the postpartum period. These findings provide new insight into the dynamic transcriptional regulatory networks and chromatin-based mechanisms controlling gene expression in the myometrium across gestational stages providing new therapeutic targets for reproductive disorders.