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Dynein complexes are large, multi-unit assemblies involved in many biological processes via their critical roles in protein transport and axoneme motility. Using next-generation sequencing of infertile men presenting with low or no sperm in their ejaculates, we identified damaging variants in the dynein-related gene AXDND1. We thus hypothesised that AXDND1 is a critical regulator of male fertility. To test this hypothesis, we produced a knockout mouse model. Axdnd1−/− males were sterile at all ages but presented with an evolving testis phenotype wherein they could undergo one round of histologically replete spermatogenesis followed by a rapid depletion of the seminiferous epithelium. Marker experiments identified a role for AXDND1 in maintaining the balance between differentiation-committed and self-renewing spermatogonial populations, resulting in disproportionate production of differentiating cells in the absence of AXDND1 and increased sperm production during initial spermatogenic waves. Moreover, long-term spermatogonial maintenance in the Axdnd1 knockout was compromised, ultimately leading to catastrophic germ cell loss, destruction of blood–testis barrier integrity and immune cell infiltration. In addition, sperm produced during the first wave of spermatogenesis were immotile due to abnormal axoneme structure, including the presence of ectopic vesicles and abnormalities in outer dense fibres and microtubule doublet structures. Sperm output was additionally compromised by a severe spermiation defect and abnormal sperm individualisation. Collectively these data identify AXDND1 as an atypical dynein complex-related protein with a role in protein/vesicle transport of relevance to spermatogonial function and sperm tail formation in mice and humans. This study underscores the importance of studying the consequences of gene loss-of-function on both the establishment and maintenance of male fertility.

Alpha, beta, and gamma tubulins are essential building blocks for all eukaryotic cells. The functions of the non-canonical tubulins, delta, epsilon, and zeta, however, remain poorly understood and their requirement in mammalian development untested. Herein we have used a spermatogenesis model to define epsilon tubulin (TUBE1) function in mice. We show that TUBE1 is essential for the function of multiple complex microtubule arrays, including the meiotic spindle, axoneme and manchette and in its absence, there is a dramatic loss of germ cells and male sterility. Moreover, we provide evidence for the interplay between TUBE1 and katanin-mediated microtubule severing, and for the sub-specialization of individual katanin paralogs in the regulation of specific microtubule arrays.

The transition zone is a specialised gate at the base of cilia/flagella, which separates the ciliary compartment from the cytoplasm and strictly regulates protein entry. We identified a potential new regulator of the male germ cell transition zone, CEP76. We demonstrated that CEP76 was involved in the selective entry and incorporation of key proteins required for sperm function and fertility into the ciliary compartment and ultimately the sperm tail. In the mutant, sperm tails were shorter and immotile as a consequence of deficits in essential sperm motility proteins including DNAH2 and AKAP4, which accumulated at the sperm neck in the mutant. Severe annulus, fibrous sheath, and outer dense fibre abnormalities were also detected in sperm lacking CEP76. Finally, we identified that CEP76 dictates annulus positioning and structure. This study suggests CEP76 as a male germ cell transition zone protein and adds further evidence to the hypothesis that the spermatid transition zone and annulus are part of the same functional structure.

In the male mouse germ line, PIWI-interacting RNAs (piRNAs), bound by the PIWI protein MIWI2 (PIWIL4), guide DNA methylation of young active transposons through SPOCD1. However, the underlying mechanisms of SPOCD1-mediated piRNA-directed transposon methylation and whether this pathway functions to protect the human germ line remain unknown. We identified loss-of-function variants in human SPOCD1 that cause defective transposon silencing and male infertility. Through the analysis of these pathogenic alleles, we discovered that the uncharacterized protein C19ORF84 interacts with SPOCD1. DNMT3C, the DNA methyltransferase responsible for transposon methylation, associates with SPOCD1 and C19ORF84 in fetal gonocytes. Furthermore, C19ORF84 is essential for piRNA-directed DNA methylation and male mouse fertility. Finally, C19ORF84 mediates the in vivo association of SPOCD1 with the de novo methylation machinery. In summary, we have discovered a conserved role for the human piRNA pathway in transposon silencing and C19ORF84, an uncharacterized protein essential for orchestrating piRNA-directed DNA methylation.

Currently, most men with infertility cannot be given an aetiology, which reflects a lack of knowledge around gamete production and how it is affected by genetics and the environment. A failure to recognize the burden of male infertility and its potential as a biomarker for systemic illness exists. The absence of such knowledge results in patients generally being treated as a uniform group, for whom the strategy is to bypass the causality using medically assisted reproduction (MAR) techniques. In doing so, opportunities to prevent co-morbidity are missed and the burden of MAR is shifted to the woman. To advance understanding of men's reproductive health, longitudinal and multi-national centres for data and sample collection are essential. Such programmes must enable an integrated view of the consequences of genetics, epigenetics and environmental factors on fertility and offspring health. Definition and possible amelioration of the consequences of MAR for conceived children are needed. Inherent in this statement is the necessity to promote fertility restoration and/or use the least invasive MAR strategy available. To achieve this aim, protocols must be rigorously tested and the move towards personalized medicine encouraged. Equally, education of the public, governments and clinicians on the frequency and consequences of infertility is needed. Health options, including male contraceptives, must be expanded, and the opportunities encompassed in such investment understood. The pressing questions related to male reproductive health, spanning the spectrum of andrology are identified in the Expert Recommendation.

Katanins, a class of microtubule-severing enzymes, are potent M-phase regulators in oocytes and somatic cells. How the complex and evolutionarily crucial, male mammalian meiotic spindle is sculpted remains unknown. Here, using multiple single and double gene knockout mice, we reveal that the canonical katanin A-subunit KATNA1 and its close paralogue KATNAL1 together execute multiple aspects of meiosis. We show KATNA1 and KATNAL1 collectively regulate the male meiotic spindle, cytokinesis and midbody abscission, in addition to diverse spermatid remodelling events, including Golgi organisation, and acrosome and manchette formation. We also define KATNAL1-specific roles in sperm flagellum development, manchette regulation and sperm-epithelial disengagement. Finally, using proteomic approaches, we define the KATNA1, KATNAL1 and KATNB1 mammalian testis interactome, which includes a network of cytoskeletal and vesicle trafficking proteins. Collectively, we reveal that the presence of multiple katanin A-subunit paralogs in mammalian spermatogenesis allows for 'customised cutting' via neofunctionalisation and protective buffering via gene redundancy.

The development and function of male gametes is dependent on a dynamic microtubule network, yet how this is regulated remains poorly understood. We have recently shown that microtubule severing, via the action of the meiotic AAA ATPase protein clade, plays a crucial role in this process. Here, we sought to elucidate the roles of spastin, an as-yet-unexplored member of this clade in spermatogenesis. Using a SpastKO/KO mouse model, we reveal that spastin loss resulted in a complete loss of functional germ cells. Spastin plays a crucial role in the assembly and function of the male meiotic spindle. Consistent with meiotic failure, round spermatid nuclei were enlarged, indicating aneuploidy, but were still able to enter spermiogenesis. During spermiogenesis, we observed extreme abnormalities in manchette structure, acrosome biogenesis and, commonly, a catastrophic loss of nuclear integrity. This work defines an essential role for spastin in regulating microtubule dynamics during spermatogenesis, and is of potential relevance to individuals carrying spastin variants and to the medically assisted reproductive technology industry.

A common herbicide, atrazine, is associated with poor health. Atrazine acts as an endocrine disruptor at supra-environmental levels. Little research, however, has been conducted regarding chronic exposure to environmental atrazine concentrations across generations. This study utilized comprehensive endpoint measures to investigate the effects of chronic exposure to a conservative atrazine concentration (0.02 ng/mL), measured in Australian waterways, on male mice fertility across two generations. Mice were exposed through the maternal line, from the pre-conception period and through the F1 and F2 generations until three or six months of age. Atrazine did not impact sperm function, testicular morphology nor germ cell parameters but did alter the expression of steroidogenic genes in the F1, down-regulating the expression of Cyp17a1 (Cytochrome P450 family 17, subfamily A member 1; p = 0.0008) and Ddx4 (DEAD-box helicase 4; p = 0.007), and up-regulating the expression of Star (Steroidogenic acute regulatory protein; p = 0.017). In the F2, atrazine induced up-regulation in the expression of Star (p = 0.016). The current study demonstrates that chronic exposure to an environmentally relevant atrazine concentration perturbs testicular steroid-associated gene expression that varies across generations. Future studies through the paternal and combined parental lineages should be undertaken to further elucidate the multigenerational effects of atrazine on male fertility.

In article number 2101291, Reza Nosrati and co-workers develop a scalable 3D sorting platform for one-step semen purification and high-quality sperm selection. The Sperm Syringe selects sperm with over 65% improvement in both DNA integrity and morphology, considerably outperforming the current best clinical practices for sperm selection in assisted reproduction.

BACKGROUND: The interferon response can influence the primary and metastatic activity of breast cancers and can interact with checkpoint immunotherapy to modulate its effects. Using N-ethyl-N-nitrosourea mutagenesis, we found a mouse with an activating mutation in oligoadenylate synthetase 2 (Oas2), a sensor of viral double stranded RNA, that resulted in an interferon response and prevented lactation in otherwise healthy mice. METHODS: To determine if sole activation of Oas2 could alter the course of mammary cancer, we combined the Oas2 mutation with the MMTV-PyMT oncogene model of breast cancer and examined disease progression and the effects of checkpoint immunotherapy using Kaplan-Meier survival analysis with immunohistochemistry and flow cytometry. RESULTS: Oas2 mutation prevented pregnancy from increasing metastases to lung. Checkpoint immunotherapy with antibodies against programmed death-ligand 1 was more effective when the Oas2 mutation was present. CONCLUSIONS: These data establish OAS2 as a therapeutic target for agents designed to reduce metastases and increase the effectiveness of checkpoint immunotherapy.

Sperm motility is a significant predictor of male fertility potential and is directly linked to fertilization success in both natural and some forms of assisted reproduction. Sperm motility can be impaired by both genetic and environmental factors, with asthenozoospermia being a common clinical presentation. Moreover, in the setting of assisted reproductive technology clinics, there is a distinct absence of effective and noninvasive technology to increase sperm motility without detriment to the sperm cells. Here, a new method is presented to boost sperm motility by increasing the intracellular rate of metabolic activity using high frequency ultrasound. An increase of 34% in curvilinear velocity (VCL), 10% in linearity, and 32% in the number of motile sperm cells is shown by rendering immotile sperm motile, after just 20 s exposure. A similar effect with an increase of 15% in VCL treating human sperm with the same setting is also identified. This cell level mechanotherapy approach causes no significant change in cell viability or DNA fragmentation index, and, as such, has the potential to be applied to encourage natural fertilization or less invasive treatment choices such as in vitro fertilization rather than intracytoplasmic injection.

Selection of high‐quality sperm is crucial to assisted reproduction. However, conventional clinical methods for sperm selection are manual and prone to operator errors. This article presents ‘sperm syringe', a scalable technology that mimics the highly parallelized 3D selection process in vivo via a 3D network of 560 microchannels to select high‐quality sperm. Sperm syringe retrieves more than 41% of healthy sperm from the initial sperm sample in under 15 min, providing a sufficient volume (≈500 µL) and number (1,600,000) of high‐quality sperm for fertility treatments. Experiments with bull and human sperm indicate 65% improvement in selected sperm morphology and DNA integrity, considerably outperforming the current best clinical practices. This approach enables the selection of a subpopulation of high‐quality human sperm from an oligozoospermia sample with DNA integrity below the reference value for fertility. The fabrication method of the device is also simple and scalable, representing a commercially viable technology for translation and clinical adoption. Sperm syringe provides a promising opportunity for clinics to use less invasive assisted reproductive technologies (ARTs) over intracytoplasmic sperm injection, thus reducing the associated clinical workload and optimizing long‐term health outcomes for ART‐conceived children.

De novo mutations are known to play a prominent role in sporadic disorders with reduced fitness. We hypothesize that de novo mutations play an important role in severe male infertility and explain a portion of the genetic causes of this understudied disorder. To test this hypothesis, we utilize trio-based exome sequencing in a cohort of 185 infertile males and their unaffected parents. Following a systematic analysis, 29 of 145 rare (MAF < 0.1%) protein-altering de novo mutations are classified as possibly causative of the male infertility phenotype. We observed a significant enrichment of loss-of-function de novo mutations in loss-of-function-intolerant genes (p-value = 1.00 × 10-5) in infertile men compared to controls. Additionally, we detected a significant increase in predicted pathogenic de novo missense mutations affecting missense-intolerant genes (p-value = 5.01 × 10-4) in contrast to predicted benign de novo mutations. One gene we identify, RBM5, is an essential regulator of male germ cell pre-mRNA splicing and has been previously implicated in male infertility in mice. In a follow-up study, 6 rare pathogenic missense mutations affecting this gene are observed in a cohort of 2,506 infertile patients, whilst we find no such mutations in a cohort of 5,784 fertile men (p-value = 0.03). Our results provide evidence for the role of de novo mutations in severe male infertility and point to new candidate genes affecting fertility.

Male infertility is a common condition affecting at least 7% of men worldwide and is often genetic in origin. Using whole exome sequencing, we recently discovered three hemizygous, likely damaging variants in DDB1- and CUL4-associated factor 12-like protein 1 (DCAF12L1) in men with azoospermia. DCAF12L1 is located on the X-chromosome and as identified by single cell sequencing studies, its expression is enriched in human testes and specifically in Sertoli cells and spermatogonia. However, very little is known about the role of DCAF12L1 in spermatogenesis, thus we generated a knockout mouse model to further explore the role of DCAF12L1 in male fertility. Knockout mice were generated using CRISPR/Cas9 technology to remove the entire coding region of Dcaf12l1 and were assessed for fertility over a broad range of ages (2-8 months of age). Despite outstanding genetic evidence in men, loss of DCAF12L1 had no discernible impact on male fertility in mice, as highlighted by breeding trials, histological assessment of the testis and epididymis, daily sperm production and evaluation of sperm motility using computer assisted methods. This disparity is likely due to the parallel evolution, and subsequent divergence, of DCAF12 family members in mice and men or the presence of compounding environmental factors in men.

STUDY QUESTION: What is the load, distribution and added clinical value of secondary findings (SFs) identified in exome sequencing (ES) of patients with non-obstructive azoospermia (NOA)? SUMMARY ANSWER: One in 28 NOA cases carried an identifiable, medically actionable SF. WHAT IS KNOWN ALREADY: In addition to molecular diagnostics, ES allows assessment of clinically actionable disease-related gene variants that are not connected to the patient's primary diagnosis, but the knowledge of which may allow the prevention, delay or amelioration of late-onset monogenic conditions. Data on SFs in specific clinical patient groups, including reproductive failure, are currently limited. STUDY DESIGN, SIZE, DURATION: The study group was a retrospective cohort of patients with NOA recruited in 10 clinics across six countries and formed in the framework of the international GEMINI (The GEnetics of Male INfertility Initiative) study. PARTICIPANTS/MATERIALS, SETTING, METHODS: ES data of 836 patients with NOA were exploited to analyze SFs in 85 genes recommended by the American College of Medical Genetics and Genomics (ACMG), Geisinger's MyCode, and Clinical Genome Resource. The identified 6374 exonic variants were annotated with ANNOVAR and filtered for allele frequency, retaining 1381 rare or novel missense and loss-of-function variants. After automatic assessment of pathogenicity with ClinVar and InterVar, 87 variants were manually curated. The final list of confident disease-causing SFs was communicated to the corresponding GEMINI centers. When patient consent had been given, available family health history and non-andrological medical data were retrospectively assessed. MAIN RESULTS AND THE ROLE OF CHANCE: We found a 3.6% total frequency of SFs, 3.3% from the 59 ACMG SF v2.0 genes. One in 70 patients carried SFs in genes linked to familial cancer syndromes, whereas 1 in 60 cases was predisposed to congenital heart disease or other cardiovascular conditions. Retrospective assess

Non-obstructive azoospermia (NOA) is the most severe form of male infertility and typically incurable. Defining the genetic basis of NOA has proven challenging, and the most advanced classification of NOA subforms is not based on genetics, but simple description of testis histology. In this study, we exome-sequenced over 1000 clinically diagnosed NOA cases and identified a plausible recessive Mendelian cause in 20%. We find further support for 21 genes in a 2-stage burden test with 2072 cases and 11,587 fertile controls. The disrupted genes are primarily on the autosomes, enriched for undescribed human "knockouts", and, for the most part, have yet to be linked to a Mendelian trait. Integration with single-cell RNA sequencing data shows that azoospermia genes can be grouped into molecular subforms with synchronized expression patterns, and analogs of these subforms exist in mice. This analysis framework identifies groups of genes with known roles in spermatogenesis but also reveals unrecognized subforms, such as a set of genes expressed across mitotic divisions of differentiating spermatogonia. Our findings highlight NOA as an understudied Mendelian disorder and provide a conceptual structure for organizing the complex genetics of male infertility, which may provide a rational basis for disease classification.

BACKGROUND: Thousands of genes are expressed during spermatogenesis and male infertility has a strong genetic component. Within this study, we focus on the role of Zfr2 in male fertility, a gene previously implicated in human male fertility. To date, very little is known about the role of ZFR2 in either humans or mice. To this end, the requirement for ZFR2 in male fertility was assessed using a knockout mouse model. RESULTS: Zfr2 was found to be expressed in the testes of both humans and mice. Deletion of Zfr2 was achieved via removal of exon 2 using CRISPR-Cas9 methods. The absence of Zfr2 did not result in a reduction in any fertility parameters assessed. Knockout males were capable of fostering litter sizes equal to wild type males, and there were no effects of Zfr2 knockout on sperm number or motility. We note Zfr2 knockout females were also fertile. CONCLUSIONS: The absence of Zfr2 alone is not sufficient to cause a reduction in male fertility in mice.

Male infertility is a global health issue; yet to a large extent, our knowledge of its causes, impact and consequence is largely unknown. Recent data indicate that infertile men have an increased risk of somatic disorders such as cancer and die younger compared to fertile men. Moreover, several studies point to a significant adverse effect on the health of the offspring. From the startling lack of progress in male contraception combined with the paucity of improvements in the diagnosis of male infertility, we conclude there is a crisis in male reproductive health. The Male Reproductive Health Initiative has been organized to directly address these issues (www.eshre.eu/Specialty-groups/Special-Interest-Groups/Andrology/MRHI). The Working Group will formulate an evidence-based strategic road map outlining the ways forward. This is an open consortium desiring to engage with all stakeholders and governments.

The fallopian tube is lined with a highly complex folded epithelium surrounding a lumen that progressively narrows. To study the influence of this labyrinthine complexity on sperm behavior, we use droplet microfluidics to create soft curved interfaces over a range of curvatures corresponding to the in vivo environment. We reveal a dynamic response mechanism in sperm, switching from a progressive surface-aligned motility mode at low curvatures (larger droplets), to an aggressive surface-attacking mode at high curvatures (smaller droplets of <50 µm-radius). We show that sperm in the attacking mode swim ~33% slower, spend 1.66-fold longer at the interface and have a 66% lower beating amplitude than in the progressive mode. These findings demonstrate that surface curvature within the fallopian tube alters sperm motion from a faster surface aligned locomotion in distal regions to a prolonged physical contact with the epithelium near the site of fertilization, the latter being known to promote capacitation and fertilization competence.

Fertilization requires sperm to travel long distances through the complex environment of the female reproductive tract. Despite the strong association between poor motility and infertility, the kinetics of sperm tail movement and the role individual proteins play in this process is poorly understood. Here, we use a high spatiotemporal sperm imaging system and an analysis protocol to define the role of CRISPs in the mechanobiology of sperm function. Each of CRISP1, CRISP2, and CRISP4 is required to optimize sperm flagellum waveform. Each plays an autonomous role in defining beat frequency, flexibility, and power dissipation. We thus posit that the expansion of the CRISP family from one member in basal vertebrates, to three in most mammals, and four in numerous rodents, represents an example of neofunctionalization wherein proteins with a common core function, boosting power output, have evolved to optimize different aspects of sperm tail performance.

BACKGROUND: Human male infertility has a notable genetic component, including well-established diagnoses such as Klinefelter syndrome, Y-chromosome microdeletions and monogenic causes. Approximately 4% of all infertile men are now diagnosed with a genetic cause, but a majority (60-70%) remain without a clear diagnosis and are classified as unexplained. This is likely in large part due to a delay in the field adopting next-generation sequencing (NGS) technologies, and the absence of clear statements from field leaders as to what constitutes a validated cause of human male infertility (the current paper aims to address this). Fortunately, there has been a significant increase in the number of male infertility NGS studies. These have revealed a considerable number of novel gene-disease relationships (GDRs), which each require stringent assessment to validate the strength of genotype-phenotype associations. To definitively assess which of these GDRs are clinically relevant, the International Male Infertility Genomics Consortium (IMIGC) has identified the need for a systematic review and a comprehensive overview of known male infertility genes and an assessment of the evidence for reported GDRs. OBJECTIVE AND RATIONALE: In 2019, the first standardised clinical validity assessment of monogenic causes of male infertility was published. Here, we provide a comprehensive update of the subsequent 1.5 years, employing the joint expertise of the IMIGC to systematically evaluate all available evidence (as of 1 July 2020) for monogenic causes of isolated or syndromic male infertility, endocrine disorders or reproductive system abnormalities affecting the male sex organs. In addition, we systematically assessed the evidence for all previously reported possible monogenic causes of male infertility, using a framework designed for a more appropriate clinical interpretation of disease genes. SEARCH METHODS: We performed a literature search according to the PRISMA guidelines up until 1

We demonstrate a technique for investigating the energetics of flagella or cilia. We record the planar beating of tethered mouse sperm at high resolution. Beating waveforms are reconstructed using proper orthogonal decomposition of the centerline tangent-angle profiles. Energy conservation is employed to obtain the mechanical power exerted by the dynein motors from the observed kinematics. A large proportion of the mechanical power exerted by the dynein motors is dissipated internally by the motors themselves. There could also be significant dissipation within the passive structures of the flagellum. The total internal dissipation is considerably greater than the hydrodynamic dissipation in the aqueous medium outside. The net power input from the dynein motors in sperm from Crisp2-knockout mice is significantly smaller than in wildtype samples, indicating that ion-channel regulation by cysteine-rich secretory proteins controls energy flows powering the axoneme.

BACKGROUND: Male infertility is a prevalent clinical presentation for which there is likely a strong genetic component due to the thousands of genes required for spermatogenesis. Within this study we investigated the role of the gene Scrn1 in male fertility. Scrn1 is preferentially expressed in XY gonads during the period of sex determination and in adult Sertoli cells based on single cell RNA sequencing. We investigated the expression of Scrn1 in juvenile and adult tissues and generated a knockout mouse model to test its role in male fertility. RESULTS: Scrn1 was expressed at all ages examined in the post-natal testis; however, its expression peaked at postnatal days 7-14 and SCRN1 protein was clearly localized to Sertoli cells. Scrn1 deletion was achieved via removal of exon 3, and its loss had no effect on male fertility or sex determination. Knockout mice were capable of siring litters of equal size to wild type counterparts and generated equal numbers of sperm with comparable motility and morphology characteristics. CONCLUSIONS: Scrn1 was found to be dispensable for male fertility, but this study identifies SCRN1 as a novel marker of the Sertoli cell cytoplasm.

The analysis of spermatozoa morphology is fundamental to understand male fertility and the etiology of infertility. Traditionally scanning electron microscopy (SEM) has been used to define surface topology. Recently, however, it has become a critical tool for three-dimensional analysis of internal cellular ultrastructure. Modern SEM provides nanometer-scale resolution, but the meaningfulness of such information is proportional to the quality of the sample preservation. In this study, we demonstrate that sperm quickly and robustly adhere to gold-coated surfaces. Leveraging this property, we developed three step-by-step protocols fulfilling different needs for sperm imaging: chemically fixed monolayers for SEM examination of the external morphology, and two high-pressure freezing-based protocols for fast SEM examination of full cell internal morphology and focused ion-beam SEM tomography. These analyses allow previously unappreciated insights into mouse sperm ultrastructure, including the identification of novel structures within the fibrous sheath and domain-specific interactions between the plasma membrane and exosome-like structures.

Katanin microtubule-severing enzymes are crucial executers of microtubule regulation. Here, we have created an allelic loss-of-function series of the katanin regulatory B-subunit KATNB1 in mice. We reveal that KATNB1 is the master regulator of all katanin enzymatic A-subunits during mammalian spermatogenesis, wherein it is required to maintain katanin A-subunit abundance. Our data shows that complete loss of KATNB1 from germ cells is incompatible with sperm production, and we reveal multiple new spermatogenesis functions for KATNB1, including essential roles in male meiosis, acrosome formation, sperm tail assembly, regulation of both the Sertoli and germ cell cytoskeletons during sperm nuclear remodelling, and maintenance of seminiferous epithelium integrity. Collectively, our findings reveal that katanins are able to differentially regulate almost all key microtubule-based structures during mammalian male germ cell development, through the complexing of one master controller, KATNB1, with a 'toolbox' of neofunctionalised katanin A-subunits.

STUDY QUESTION: What are the causative genetic variants in patients with male infertility due to severe sperm motility disorders? SUMMARY ANSWER: We identified high confidence disease-causing variants in multiple genes previously associated with severe sperm motility disorders in 10 out of 21 patients (48%) and variants in novel candidate genes in seven additional patients (33%). WHAT IS KNOWN ALREADY: Severe sperm motility disorders are a form of male infertility characterised by immotile sperm often in combination with a spectrum of structural abnormalities of the sperm flagellum that do not affect viability. Currently, depending on the clinical sub-categorisation, up to 50% of causality in patients with severe sperm motility disorders can be explained by pathogenic variants in at least 22 genes. STUDY DESIGN, SIZE, DURATION: We performed exome sequencing in 21 patients with severe sperm motility disorders from two different clinics. PARTICIPANTS/MATERIALS, SETTING, METHOD: Two groups of infertile men, one from Argentina (n = 9) and one from Australia (n = 12), with clinically defined severe sperm motility disorders (motility <5%) and normal morphology values of 0-4%, were included. All patients in the Argentine cohort were diagnosed with DFS-MMAF, based on light and transmission electron microscopy. Sperm ultrastructural information was not available for the Australian cohort. Exome sequencing was performed in all 21 patients and variants with an allele frequency of <1% in the gnomAD population were prioritised and interpreted. MAIN RESULTS AND ROLE OF CHANCE: In 10 of 21 patients (48%), we identified pathogenic variants in known sperm assembly genes: CFAP43 (3 patients); CFAP44 (2 patients), CFAP58 (1 patient), QRICH2 (2 patients), DNAH1 (1 patient) and DNAH6 (1 patient). The diagnostic rate did not differ markedly between the Argentinian and the Australian cohort (55% and 42%, respectively). Furthermore, we identified patients with variants in the novel human c

Haprin (TRIM36) is a ubiquitin-protein ligase that mediates ubiquitination and subsequent proteasomal degradation of target proteins. It is expressed in the testes in both mice and humans and is thought to be involved in spermiogenesis, the acrosome reaction, and fertilization. However, the functional role of Haprin is poorly understood. The aim of this study was to investigate the physiological role of Haprin in fertility. Homozygous haprin-deficient mice were generated and these mice, and their spermatozoa, were analyzed to detect morphological and fertility-related abnormalities. In these models, normal spermatogenesis was observed but sperm quality was reduced with haprin-deficient mice having poorer sperm morphology and motility than wild-type mice. Interestingly, haprin-deficient mice showed normal in vivo fertility but could not fertilize oocytes under standard in vitro fertilization conditions. In conclusion, this study demonstrated that Haprin deficiency causes morphological abnormalities in spermatozoa, indicating that Haprin is involved in spermiogenesis.

STUDY QUESTIONS: What are the long-term health and reproductive outcomes for young men conceived using ICSI whose fathers had spermatogenic failure (STF)? Are there epigenetic consequences of ICSI conception? WHAT IS KNOWN ALREADY: Currently, little is known about the health of ICSI-conceived adults, and in particular the health and reproductive potential of ICSI-conceived men whose fathers had STF. Only one group to date has assessed semen parameters and reproductive hormones in ICSI-conceived men and suggested higher rates of impaired semen quality compared to spontaneously conceived (SC) peers. Metabolic parameters in this same cohort of men were mostly comparable. No study has yet evaluated other aspects of adult health. STUDY DESIGN SIZE DURATION: This cohort study aims to evaluate the general health and development (aim 1), fertility and metabolic parameters (aim 2) and epigenetic signatures (aim 3) of ICSI-conceived sons whose fathers had STF (ICSI study group). There are three age-matched control groups: ICSI-conceived sons whose fathers had obstructive azoospermia (OAZ) and who will be recruited in this study, as well as IVF sons and SC sons, recruited from other studies. Of 1112 ICSI parents including fathers with STF and OAZ, 78% (n = 867) of mothers and 74% (n = 823) of fathers were traced and contacted. Recruitment of ICSI sons started in March 2017 and will finish in July 2020. Based on preliminary participation rates, we estimate the following sample size will be achieved for the ICSI study group: mothers n = 275, fathers n = 225, sons n = 115. Per aim, the sample sizes of OAZ-ICSI (estimated), IVF and SC controls are: Aim 1-OAZ-ICSI: 28 (maternal surveys)/12 (son surveys), IVF: 352 (maternal surveys)/244 (son surveys), SC: 428 (maternal surveys)/255 (son surveys); Aim 2-OAZ-ICSI: 12, IVF: 72 (metabolic data), SC: 391 (metabolic data)/365 (reproductive data); Aim 3-OAZ-ICSI: 12, IVF: 71, SC: 292. PARTICIPANTS/MATERIALS SETTING METHODS: Eligible parent

Approximately 2-15% of couples experience infertility, and around half of these cases are attributed to male infertility. We previously identified TBC1D21 as a sterility-related RabGAP gene derived from infertile men. However, the in vivo function of TBC1D21 in male fertility remains unclear. Here, we show that loss of Tbc1d21 in mice resulted in male infertility, characterized by defects in sperm tail structure and diminished sperm motility. The mitochondria of the sperm-tail had an abnormal irregular arrangement, abnormal diameter, and structural defects. Moreover, the axoneme structure of sperm tails was severely disturbed. Several TBC1D21 interactors were selected via proteomic analysis and functional grouping. Two of the candidate interactors, a subunit protein of translocase in the outer membrane of mitochondria (TOMM20) and an inner arm component of the sperm tail axoneme (Dynein Heavy chain 7, DNAH7), confirmed in vivo physical co-localization with TBC1D21. In addition, TOMM20 and DNAH7 detached and dispersed outside the axoneme in Tbc1d21-deficient sperm, instead of aligning with the axoneme. From a clinical perspective, the transcript levels of TBC1D21 in sperm from teratozoospermia cases were significantly reduced when compared with those in normozoospermia. We concluded that TBC1D21 is critical for mitochondrial and axoneme development of mammalian sperm.

Globozoospermia is a rare form of male infertility where men produce round-headed sperm that are incapable of fertilizing an oocyte naturally. In a previous study where we undertook a whole exome screen to define novel genetic causes of globozoospermia, we identified homozygous mutations in the gene PDCD2L Two brothers carried a p.(Leu225Val) variant predicted to introduce a novel splice donor site, thus presenting PDCD2L as a potential regulator of male fertility. In this study, we generated a Pdcd2l knockout mouse to test its role in male fertility. Contrary to the phenotype predicted from its testis-enriched expression pattern, Pdcd2l null mice died during embryogenesis. Specifically, we identified that Pdcd2l is essential for post-implantation embryonic development. Pdcd2l-/- embryos were resorbed at embryonic days 12.5-17.5 and no knockout pups were born, while adult heterozygous Pdcd2l males had comparable fertility to wildtype males. To specifically investigate the role of PDCD2L in germ cells, we employed Drosophila melanogaster as a model system. Consistent with the mouse data, global knockdown of trus, the fly ortholog of PDCD2L, resulted in lethality in flies at the third instar larval stage. However, germ cell-specific knockdown with two germ cell drivers did not affect male fertility. Collectively, these data suggest that PDCD2L is not essential for male fertility. By contrast, our results demonstrate an evolutionarily conserved role of PDCD2L in development.

STUDY QUESTION: Can exome sequencing identify new genetic causes of globozoospermia? SUMMARY ANSWER: Exome sequencing in 15 cases of unexplained globozoospermia revealed deleterious mutations in seven new genes, of which two have been validated as causing globozoospermia when knocked out in mouse models. WHAT IS KNOWN ALREADY: Globozoospermia is a rare form of male infertility characterised by round-headed sperm and malformation of the acrosome. Although pathogenic variants in DPY19L2 and SPATA16 are known causes of globozoospermia and explain up to 70% of all cases, genetic causality remains unexplained in the remaining patients. STUDY DESIGN, SIZE, DURATION: After pre-screening 16 men for mutations in known globozoospermia genes DPY19L2 and SPATA16, exome sequencing was performed in 15 males with globozoospermia or acrosomal hypoplasia of unknown aetiology. PARTICIPANTS/MATERIALS, SETTING, METHOD: Targeted next-generation sequencing and Sanger sequencing was performed for all 16 patients to screen for single-nucleotide variants and copy number variations in DPY19L2 and SPATA16. After exclusion of one patient with DPY19L2 mutations, we performed exome sequencing for the 15 remaining subjects. We prioritised recessive and X-linked protein-altering variants with an allele frequency of <0.5% in the population database GnomAD in genes with an enhanced expression in the testis. All identified candidate variants were confirmed in patients and, where possible, in family members using Sanger sequencing. Ultrastructural examination of semen from one of the patients allowed for a precise phenotypic characterisation of abnormal spermatozoa. MAIN RESULTS AND ROLE OF CHANCE: After prioritisation and validation, we identified possibly causative variants in eight of 15 patients investigated by exome sequencing. The analysis revealed homozygous nonsense mutations in ZPBP and CCDC62 in two unrelated patients, as well as rare missense mutations in C2CD6 (also known as ALS2CR11), CCI

Background The sperm protein IZUMO1 (Izumo sperm-egg fusion 1) and its recently identified binding partner on the oolemma, IZUMO1R, are among the first ligand-receptor pairs shown to be essential for gamete recognition and adhesion. However, the IZUMO1-IZUMO1R interaction does not appear to be directly responsible for promoting the fusion of the gamete membranes, suggesting that this critical phase of the fertilization cascade requires the concerted action of alternative fusogenic machinery. It has therefore been proposed that IZUMO1 may play a secondary role in the organization and/or stabilization of higher-order heteromeric complexes in spermatozoa that are required for membrane fusion. Results Here, we show that fertilization-competent (acrosome reacted) mouse spermatozoa harbor several high molecular weight protein complexes, a subset of which are readily able to adhere to solubilized oolemmal proteins. At least two of these complexes contain IZUMO1 in partnership with GLI pathogenesis-related 1 like 1 (GLIPR1L1). This interaction is associated with lipid rafts and is dynamically remodeled upon the induction of acrosomal exocytosis in preparation for sperm adhesion to the oolemma. Accordingly, the selective ablation of GLIPR1L1 leads to compromised sperm function characterized by a reduced ability to undergo the acrosome reaction and a failure of IZUMO1 redistribution. Conclusions Collectively, this study characterizes multimeric protein complexes on the sperm surface and identifies GLIPRL1L1 as a physiologically relevant regulator of IZUMO1 function and the fertilization process.

Infertility in men and women is a complex genetic trait with shared biological bases between the sexes. Here, we perform a series of rare variant analyses across 73,185 women and men to identify genes that contribute to primary gonadal dysfunction. We report CSMD1, a complement regulatory protein on chromosome 8p23, as a strong candidate locus in both sexes. We show that CSMD1 is enriched at the germ-cell/somatic-cell interface in both male and female gonads. Csmd1-knockout males show increased rates of infertility with significantly increased complement C3 protein deposition in the testes, accompanied by severe histological degeneration. Knockout females show significant reduction in ovarian quality and breeding success, as well as mammary branching impairment. Double knockout of Csmd1 and C3 causes non-additive reduction in breeding success, suggesting that CSMD1 and the complement pathway play an important role in the normal postnatal development of the gonads in both sexes.

BACKGROUND: Defining the mechanisms that establish and regulate the transmission of epigenetic information from parent to offspring is critical for understanding disease heredity. Currently, the molecular pathways that regulate epigenetic information in the germline and its transmission to offspring are poorly understood. RESULTS: Here we provide evidence that Polycomb Repressive Complex 2 (PRC2) regulates paternal inheritance. Reduced PRC2 function in mice resulted in male sub-fertility and altered epigenetic and transcriptional control of retrotransposed elements in foetal male germ cells. Males with reduced PRC2 function produced offspring that over-expressed retrotransposed pseudogenes and had altered preimplantation embryo cleavage rates and cell cycle control. CONCLUSION: This study reveals a novel role for the histone-modifying complex, PRC2, in paternal intergenerational transmission of epigenetic effects on offspring, with important implications for understanding disease inheritance.

BACKGROUND: A significant increase in the use of intracytoplasmic sperm injection (ICSI) since its introduction in 1992 has been observed worldwide, including beyond its original intended use for severe male factor infertility. Concerns regarding ICSI include the effects of poor quality spermatozoa on offspring health and future fertility, and of the technique itself. The health and development of ICSI-conceived children beyond early infancy have not been comprehensively assessed. OBJECTIVE: A systematic review of health outcomes of ICSI-conceived offspring beyond the neonatal period compared to spontaneously conceived (SC) offspring. DESIGN: PubMed, OVID Medline/Embase, InformIT, Web of Science, and ProQuest databases were searched for studies reporting on health outcomes in ICSI-conceived offspring beyond 28 days after birth. MAIN OUTCOMES MEASURE(S): Physical and psychosocial health. RESULTS: The search strategy yielded 2826 articles. Of these, 2580 were not relevant or did not meet inclusion criteria and 138 were duplicates. One hundred and eight full-text papers were evaluated further, and 48 satisfied the inclusion criteria. Most studies reported on neurodevelopment during early infancy and childhood with reassuring results. Growth, vision, and hearing of ICSI and SC offspring also appear comparable, although important differences in general physical health, and particularly metabolic and reproductive health have been described, including recently poorer semen quality among ICSI-conceived young adult men compared to SC peers. CONCLUSION: Whilst neurodevelopment, growth, vision, and hearing appear similar between ICSI and SC children, evidence suggests differences in general physical health, and metabolic and reproductive endpoints. The clinical significance of many findings, however, remains unclear, and further prospective, large, and good quality studies with a focus on all these health outcomes in ICSI-conceived young adults are required.

© 2017 The Author(s). Cigarette smoking is undoubtedly a risk factor for lung cancer. Moreover, smokers with genetic mutations on chromosome 3p21.3, a region frequently deleted in cancer and notably in lung cancer, have a dramatically higher risk of aggressive lung cancer. The RNA binding motif 5 (RBM5) is one of the component genes in the 3p21.3 tumour suppressor region. Studies using human cancer specimens and cell lines suggest a role for RBM5 as a tumour suppressor. Here we demonstrate, for the first time, an in vivo role for RBM5 as a tumour suppressor in the mouse lung. We generated Rbm5 loss-of-function mice and exposed them to a tobacco carcinogen NNK. Upon exposure to NNK, Rbm5 loss-of-function mice developed lung cancer at similar rates to wild type mice. As tumourigenesis progressed, however, reduced Rbm5 expression lead to significantly more aggressive lung cancer i.e. increased adenocarcinoma nodule numbers and tumour size. Our data provide in vivo evidence that reduced RBM5 function, as occurs in a large number of patients, coupled with exposure to tobacco carcinogens is a risk factor for an aggressive lung cancer phenotype. These data suggest that RBM5 loss-of-function likely underpins at least part of the pro-tumourigenic consequences of 3p21.3 deletion in humans.

We identified a non-synonymous mutation in Oas2 (I405N), a sensor of viral double-stranded RNA, from an ENU-mutagenesis screen designed to discover new genes involved in mammary development. The mutation caused post-partum failure of lactation in healthy mice with otherwise normally developed mammary glands, characterized by greatly reduced milk protein synthesis coupled with epithelial cell death, inhibition of proliferation and a robust interferon response. Expression of mutant but not wild type Oas2 in cultured HC-11 or T47D mammary cells recapitulated the phenotypic and transcriptional effects observed in the mouse. The mutation activates the OAS2 pathway, demonstrated by a 34-fold increase in RNase L activity, and its effects were dependent on expression of RNase L and IRF7, proximal and distal pathway members. This is the first report of a viral recognition pathway regulating lactation.

Microdeletions of the Y chromosome (YCMs), Klinefelter syndrome (47,XXY), and CFTR mutations are known genetic causes of severe male infertility, but the majority of cases remain idiopathic. Here, we describe a novel method using single molecule Molecular Inversion Probes (smMIPs), to screen infertile men for mutations and copy number variations affecting known disease genes. We designed a set of 4,525 smMIPs targeting the coding regions of causal (n = 6) and candidate (n = 101) male infertility genes. After extensive validation, we screened 1,112 idiopathic infertile men with non-obstructive azoospermia or severe oligozoospermia. In addition to five chromosome YCMs and six other sex chromosomal anomalies, we identified five patients with rare recessive mutations in CFTR as well as a patient with a rare heterozygous frameshift mutation in SYCP3 that may be of clinical relevance. This results in a genetic diagnosis in 11-17 patients (1%-1.5%), a yield that may increase significantly when more genes are confidently linked to male infertility. In conclusion, we developed a flexible and scalable method to reliably detect genetic causes of male infertility. The assay consolidates the detection of different types of genetic variation while increasing the diagnostic yield and detection precision at the same or lower price compared with currently used methods.

The use of intra-cytoplasmic sperm injection (ICSI) has increased significantly worldwide, often chosen instead of in vitro fertilization (IVF), yet long-term health outcomes are unknown and health differences between ICSI and IVF conceptions have not been comprehensively assessed. A systematic review of health outcomes of ICSI-conceived offspring beyond the neonatal period compared to IVF-conceived offspring was carried out. PubMed, OVID Medline/Embase, Informit, Web of Science and Proquest databases were searched on 9 November 2016 for studies reporting on health outcomes in ICSI-conceived offspring beyond 28 days after birth. Physical and psychosocial health were the main outcome measures. The search strategy yielded 2781 articles; 2539 were not relevant or did not meet inclusion criteria and 137 were duplicates. One hundred and five full-text papers were evaluated further and 34 satisfied the inclusion criteria. Studies comparing ICSI- and IVF-conceived children suggest their neurodevelopment is comparable. Growth and aspects of physical health are also similar; however, studies are few and limited to childhood. ICSI-conceived children may be at increased risk of autism and intellectual impairment. No difference in risk of childhood cancer was reported in one study. Whilst the neurodevelopment of ICSI-conceived children appears comparable to those of IVF conception, data relating to neurodevelopmental disorders, growth, physical health and childhood cancer are inconclusive. Further research into health outcomes in adolescence and adulthood is required before conclusions can be drawn about the long-term safety of ICSI compared to IVF. Until then, ICSI might be better reserved for its original intended use, male-factor infertility.

Deficiency in pleomorphic adenoma gene 1 (PLAG1) leads to reduced fertility in male mice, but the mechanism by which PLAG1 contributes to reproduction is unknown. To investigate the involvement of PLAG1 in testicular function, we determined (i) the spatial distribution of PLAG1 in the testis using X-gal staining; (ii) transcriptomic consequences of PLAG1 deficiency in knock-out and heterozygous mice compared to wild-type mice using RNA-seq; and (iii) morphological and functional consequences of PLAG1 deficiency by determining testicular histology, daily sperm production and sperm motility in knock-out and wild-type mice. PLAG1 was sparsely expressed in germ cells and in Sertoli cells. Genes known to be involved in spermatogenesis were downregulated in the testes of knock-out mice, as well as Hsd17b3, which encodes a key enzyme in androgen biosynthesis. In the absence of Plag1, a number of genes involved in immune processes and epididymis-specific genes were upregulated in the testes. Finally, loss of PLAG1 resulted in significantly lowered daily sperm production, in reduced sperm motility, and in several animals, in sloughing of the germinal epithelium. Our results demonstrate that the subfertility seen in male PLAG1-deficient mice is, at least in part, the result of significantly reduced sperm output and sperm motility.

Male infertility is a major and growing problem and, in most cases, the specific root cause is unknown. Here we show that the transcription factor SOX30 plays a critical role in mouse spermatogenesis. Sox30-null mice are healthy and females are fertile, but males are sterile. In the absence of Sox30 meiosis initiates normally in both sexes but, in males, germ cell development arrests during the post-meiotic round spermatid period. In the mutant testis, acrosome and axoneme development are aberrant, multinucleated germ cells (symplasts) form and round spermatids unable to process beyond step 3 of spermiogenesis. No elongated spermatids nor spermatozoa are produced. Thus, Sox30 represents a rare example of a gene for which loss of function results in a complete arrest of spermatogenesis at the onset of spermiogenesis. Our results suggest that SOX30 mutations may underlie some instances of unexplained non-obstructive azoospermia in humans.

We identified a non-synonymous mutation in Oas2 (I405N), a sensor of viral double-stranded RNA, from an ENU-mutagenesis screen designed to discover new genes involved in mammary development. The mutation caused post-partum failure of lactation in healthy mice with otherwise normally developed mammary glands, characterized by greatly reduced milk protein synthesis coupled with epithelial cell death, inhibition of proliferation and a robust interferon response. Expression of mutant but not wild type Oas2 in cultured HC-11 or T47D mammary cells recapitulated the phenotypic and transcriptional effects observed in the mouse. The mutation activates the OAS2 pathway, demonstrated by a 34-fold increase in RNase L activity, and its effects were dependent on expression of RNase L and IRF7, proximal and distal pathway members. This is the first report of a viral recognition pathway regulating lactation.

piRNAs are critical for transposable element (TE) repression and germ cell survival during the early phases of spermatogenesis, however, their role in adult germ cells and the relative importance of piRNA methylation is poorly defined in mammals. Using a mouse model of HEN methyltransferase 1 (HENMT1) loss-of-function, RNA-Seq and a range of RNA assays we show that HENMT1 is required for the 2' O-methylation of mammalian piRNAs. HENMT1 loss leads to piRNA instability, reduced piRNA bulk and length, and ultimately male sterility characterized by a germ cell arrest at the elongating germ cell phase of spermatogenesis. HENMT1 loss-of-function, and the concomitant loss of piRNAs, resulted in TE de-repression in adult meiotic and haploid germ cells, and the precocious, and selective, expression of many haploid-transcripts in meiotic cells. Precocious expression was associated with a more active chromatin state in meiotic cells, elevated levels of DNA damage and a catastrophic deregulation of the haploid germ cell gene expression. Collectively these results define a critical role for HENMT1 and piRNAs in the maintenance of TE repression in adult germ cells and setting the spermatogenic program.

Male infertility affects at least 5% of reproductive age males. The most common pathology is a complex presentation of decreased sperm output and abnormal sperm shape and motility referred to as oligoasthenoteratospermia (OAT). For the majority of OAT men a precise diagnosis cannot be provided. Here we demonstrate that leucine-rich repeats and guanylate kinase-domain containing isoform 1 (LRGUK-1) is required for multiple aspects of sperm assembly, including acrosome attachment, sperm head shaping and the initiation of the axoneme growth to form the core of the sperm tail. Specifically, LRGUK-1 is required for basal body attachment to the plasma membrane, the appropriate formation of the sub-distal appendages, the extension of axoneme microtubules and for microtubule movement and organisation within the manchette. Manchette dysfunction leads to abnormal sperm head shaping. Several of these functions may be achieved in association with the LRGUK-1 binding partner HOOK2. Collectively, these data establish LRGUK-1 as a major determinant of microtubule structure within the male germ line.