Spermatid Development Research Articles

O-305 Mapping the entire functionally active seminal microbiota and its association with semen quality parameters

Abstract Study question Does semen harbour functionally active microorganisms, and whether the microbial composition associate with semen quality parameters? Summary answer Seminal fluid harbours functionally alive microorganisms including bacteria, viruses, archaea, viroids and fungi whose composition and metabolic functions associate with semen quality parameters. What is known already Seminal fluid has been shown to possess different microbes, where different bacteria have been associated with spermatogenesis, seminal parameters and infertility. Nevertheless, previous results are inconclusive and the core microorganismal composition in semen is not determined and whether the identified bacterial DNA sequences refer to alive/functionally active microbes is not clear. Further, there is limited knowledge of the potential host-microbe interactions. Study design, size, duration In total 78 men with age between 18 and 45 years donated semen for the study, 59 men with good quality semen parameters and 19 men with low semen quality and diagnosed asthenospermia, oligoasthenozoospermia or oligoasthenoteratozoospermia comprised control and case groups, respectively. Participants/materials, setting, methods Semen quality parameters were analysed following WHO, 2021 guidelines. Seminal fluid underwent NextSeq total RNA sequencing, separating human and non-human sequences with Hisat2 aligner. Taxonomic classification of microorganisms was obtained using Kraken2. Microbial species and human RNA-Seq analyses, comparing control and infertility groups, utilized metagenomeSeq and edgeR R packages. Human and microbial pathways were annotated using MetaCyc, followed by GSEA analysis. The integration of metabolic pathways between host and microbes was investigated. Main results and the role of chance With our total RNAseq analysis, we mapped the entire alive microbiota composing of 6453 microorganisms within the seminal fluid samples. Microbes such as bacteria, fungi, viruses, viroids and archea were identified. When analysing microbiota associations with seminal parameters, 404 microbial species (Lactobacillus, Gardnerella, Prevotella, Atopobium, Pseudomonas among others) were significantly differently present among infertile men vs. good quality semen group. The host transcriptomic analysis identified 2569 differentially expressed genes in infertile vs. good quality semen groups, involved in sperm differentiation, spermatid development, reproduction, cilium movement and meiosis. Metabolic pathway analysis detected possible metabolic activity in the host-microbiota crosstalk in FAO-PWY: fatty acid & beta-oxidation, LIPASYN-PWY: phospholipases, PWY66-429: fatty acid biosynthesis, PWY-3781: aerobic respiration I pathways. Limitations, reasons for caution Bigger sample size of infertile men would be needed to validate the study findings. Wider implications of the findings We confirm the presence of active microbes in semen with implications in seminal quality parameters such as motility, sperm count and morphology. Our results contribute to better understanding of seminal microbiota dysregulation in infertility with broader implications for reproductive health, suggesting functional links between seminal microbiota and sperm parameters. Trial registration number NA

Hydroxytyrosol Ameliorates Busulfan-Induced Oligozoospermia in a Mouse Model

Objective Hydroxytyrosol (HT), a polyphenolic component identified in olive oil and leaves, represents one of the most extensively investigated natural phenol due to its diverse beneficial biological properties. Recent studies have shown that HT exhibits protective effects on reproductive function and can improve sperm quality. However, the precise effect and underlying mechanism of HT on oligozoospermia remain unclear. This study aims to investigate the effect and mechanism of HT across varying concentrations on oligozoospermia. Methods Oligozoospermia was induced in ICR male mice via intraperitoneal injection of busulfan (BUS, 30 mg/kg). The mice were randomly categorized into five groups as Normal, BUS, HT 10 mg/kg, HT 30 mg/kg and HT 50 mg/kg. The efficacy of HT on oligozoospermia was assessed through sperm concentration and motility using a computer-assisted sperm analysis system. Testicular and epididymal histology was examined via hematoxylin-eosin staining, while cytoskeletal integrity was evaluated by immunofluorescence. Hormone levels, along with reactive oxygen species (ROS) and malondialdehyde (MDA) were examined by ELISA kits. Differentially expressed genes were identified through RNA sequencing, and the expression levels of key genes were validated by qPCR. Results The results indicated that HT (50 mg/kg) significantly increased sperm concentration, promoted morphological recovery of testicular tissue, heightened the levels of serum testosterone, follicle-stimulating hormone, luteinizing hormone, as well as decreased the accumulation of ROS and MDA in mice with oligozoospermia. RNA sequencing analysis and RT-qPCR results revealed that HT could restore spermatogenesis and ameliorate oligozoospermia by up-regulating genes related to cilium organization, microtubule-based movement, and spermatid differentiation and development. Conclusions HT demonstrates therapeutic efficacy against busulfan-induced oligozoospermia. The mechanism of HT on oligozoospermia may be related to its influence on cilium and microtubule-based movement, along with the differentiation and development of spermatids. HT shows potential as a prospective therapeutic intervention for the treatment of oligozoospermia.

A Comparative Full-Length Transcriptome Analysis Using Oxford Nanopore Technologies (ONT) in Four Tissues of Bovine Origin.

The transcriptome complexity and splicing patterns in male and female cattle are ambiguous, presenting a substantial obstacle to genomic selection programs that seek to improve productivity, disease resistance, and reproduction in cattle. A comparative transcriptomic analysis using Oxford Nanopore Technologies (ONT) was conducted in bovine testes (TESTs), ovaries (OVAs), muscles (MUSCs), and livers (LIVs). An average of 5,144,769 full-length reads were obtained from each sample. The TESTs were found to have the greatest number of alternative polyadenylation (APA) events involved in processes such as sperm flagellum development and fertilization in male reproduction. In total, 438 differentially expressed transcripts (DETs) were identified in the LIVs in a comparison of females vs. males, and 214 DETs were identified in the MUSCs between females and males. Additionally, 14,735, 36,347, and 33,885 DETs were detected in MUSC vs. LIV, MUSC vs. TEST, and OVA vs. TEST comparisons, respectively, revealing the complexity of the TEST. Gene Set Enrichment Analysis (GSEA) showed that these DETs were mainly involved in the "spermatogenesis", "flagellated sperm motility", "spermatid development", "reproduction", "reproductive process", and "microtubule-based movement" KEGG pathways. Additional studies are necessary to further characterize the transcriptome in different cell types, developmental stages, and physiological conditions in bovines and ascertain the functions of the novel transcripts.

Androgens and Notch signaling cooperate in seminiferous epithelium to regulate genes related to germ cell development and apoptosis

It was reported previously that in adult males disruption of both androgen and Notch signaling impairs spermatid development and germ cell survival in rodent seminiferous epithelium. To explain the molecular mechanisms of these effects, we focused on the interaction between Notch signaling and androgen receptor (AR) in Sertoli cells and investigate its role in the control of proteins involved in apical ectoplasmic specializations, actin remodeling during spermiogenesis, and induction of germ cell apoptosis. First, it was revealed that in rat testicular explants ex vivo both testosterone and Notch signaling modulate AR expression and cooperate in the regulation of spermiogenesis-related genes (Nectin2, Afdn, Arp2, Eps8) and apoptosis-related genes (Fasl, Fas, Bax, Bcl2). Further, altered expression of these genes was found following exposure of Sertoli cells (TM4 cell line) and germ cells (GC-2 cell line) to ligands for Notch receptors (Delta-like1, Delta-like4, and Jagged1) and/or Notch pathway inhibition. Finally, direct interactions of Notch effector, Hairy/enhancer-of-split related with YRPW motif protein 1, and the promoter of Ar gene or AR protein were revealed in TM4 Sertoli cells. In conclusion, Notch pathway activity in Sertoli and germ cells regulates genes related to germ cell development and apoptosis acting both directly and indirectly by influencing androgen signaling in Sertoli cells.

The Application of Ejaculate-Based Shotgun Proteomics for Male Infertility Screening.

Problems with the male reproductive system are of both medical and social significance. As a rule, spermatozoa and seminal plasma proteomes are investigated separately to assess sperm quality. The current study aimed to compare ejaculate proteomes with spermatozoa and seminal plasma protein profiles regarding the identification of proteins related to fertility scores. A total of 1779, 715, and 2163 proteins were identified in the ejaculate, seminal plasma, and spermatozoa, respectively. Among these datasets, 472 proteins were shared. GO enrichment analysis of the common proteins enabled us to distinguish biological processes such as single fertilization (GO:0007338), spermatid development (GO:0007286), and cell motility (GO:0048870). Among the abundant terms for GO cellular components, zona pellucida receptor complex, sperm fibrous sheath, and outer dense fiber were revealed. Overall, we identified 139 testis-specific proteins. For these proteins, PPI networks that are common in ejaculate, spermatozoa, and seminal plasma were related to the following GO biological processes: cilium movement (GO:0003341), microtubule-based movement (GO:0007018), and sperm motility (GO:0097722). For ejaculate and spermatozoa, they shared 15 common testis-specific proteins with spermatogenesis (GO:0007283) and male gamete generation (GO:0048232). Therefore, we speculated that ejaculate-based proteomics could yield new insights into the peculiar reproductive physiology and spermatozoa function of men and potentially serve as an explanation for male infertility screening.

Elevated Id2 expression causes defective meiosis and spermatogenesis in mice.

Inhibitors of DNA binding (ID) proteins mainly inhibit gene expression and regulate cell fate decisions by interacting with E-proteins. All four ID proteins (ID1-4) are present in the testis, and ID4 has a particularly important role in spermatogonial stem cell fate determination. Several lines of evidence indicate that ID proteins are involved in meiosis; however, functional experiments have not been conducted to validate this observation. In this study, we report that ID2 is enriched in spermatocytes and that forced ID2 expression in germ cells causes defects in spermatogenesis. A detailed analysis demonstrated that Id2 overexpression (Id2 OE) decreased the total number of spermatogonia and changed the dynamics of meiosis progression. Specifically, spermatocytes were enriched in the zygotene stage, and the proportion of pachytene spermatocytes was significantly decreased, indicating defects in the zygotene-pachytene transition. The number of MLH1-positive foci per cell was decreased in pachytene spermatocytes from Id2 OE testes, suggesting abnormalities in recombination. Transcriptome analysis revealed that forced Id2 expression changed the expression of a list of genes mainly associated with meiosis and spermatid development. ID2 protein is expressed in spermatocytes, and its genetic ablation in the germline does not affect spermatogenesis, likely due to genetic compensation of its family members. However, forced Id2 expression changes meiosis progression and causes defects in spermiogenesis. These data provide important evidence that ID proteins play pivotal roles in male meiosis and spermatid development.

#255 : Disrupted CD147 Causes the Acrosomal Defects of Round Spermatids and Male Infertility

Background and Aims: CD147 is a well-known cancer cell migration and metastasis regulator. In the reproductive tract, our previous results revealed that CD147 regulates the apoptosis of spermatocytes and migration of spermatogonia and spermatocytes in the testis. However, the spermatogenesis process was inhibited at the round spermatid stage in our CD147-Stra8-Cre conditional knockout mice. We then further explored the mouse phenotypes and its underlying mechanisms. Method: CD147-Stra8-Cre conditional knockout mice (CD147-cKODDx4) were generated by cross-breeding the CD147 flox mice and DDx4-Cre male mice. Testis were collected for histological and molecular analyses. Results: The testis size and weight were significantly decreased in CD147-cKODDx4 mice compared to the control mice. There were no elongated spermatozoa in the CD147-cKODDx4 seminiferous tubules and cauda epididymis. PNA staining demonstrated the acrosomal defects on 3-5 stage of round spermatids. Consistent with morphological results, single cell-seq also demonstrated the round spermatid development loss. Mechanically, the IPO5 was identified as the interaction protein with CD147 and affected the round spermatids developments. Conclusion: The present study reveals a novel role of CD147, uncovers new mechanism underlying male infertility, and provides promising targets for the development of infertility diagnosis and treatment.

Bisphenol A exposure decreases sperm production and male fertility through inhibition PCBP2 expression.

Growing evidence suggests that the exposure of bisphenol A (BPA), an endocrine disruptor that commonly present in the environment, can impair reproduction. However, conflicting results have been reported, and the underlying mechanism has not been fully understood. In this study, 3-week-old male mice were oral exposed to 50mg/kg/d BPA or equivalent corn oil for 28days. Their testis and epididymis were then collected for morphology examination by HE stains. The number of sperm was counted, and the morphology was analyzed by PNA (peptide nucleic acid) and pap staining. Fertilization capacity and successful rate were analyzed after mating with wide-type females. Spermatid DNA damage and apoptosis were evaluated by DFI, γH2AX stain, and TUNEL assay. RNA sequencing analysis was conducted to identify differentially expressed genes in testicular tissue of mice exposed to BPA. RNA interference was used to verify the regulatory mechanism of BPA exposure on gene expression in GC-2 cells. Our data showed that the total number of sperm was decreased and the morphology was impaired in BPA-exposed mice. In addition, the serum testosterone level and fertilization efficiency were also reduced. Mechanism studies showed that BPA could suppress the expression of PCBP2, a key regulatory gene in spermatid development, by activating the EZH2/H3K27me3. In conclusion, we found that BPA exposure can impair spermatid development via affecting key gene expression that is at least partially due to epigenetic modification.

Comprehensive analyses of 435 goat transcriptomes provides insight into male reproduction

A systematic analysis of genes related to reproduction is crucial for obtaining a comprehensive understanding of the molecular mechanisms that underlie male reproductive traits in mammals. Here, we utilized 435 goat transcriptome datasets to unveil the testicular tissue-specific genes (TSGs), allele-specific expression (ASE) genes and their uncharacterized transcriptional features related to male goat reproduction. Results showed a total of 1790 TSGs were identified in goat testis, which was the most among all tissues. GO enrichment analyses suggested that testicular TSGs were mainly involved in spermatogenesis, multicellular organism development, spermatid development, and flagellated sperm motility. Subsequently, a total of 95 highly conserved TSGs (HCTSGs), 508 middle conserved TSGs (MCTSGs) and 42 no conserved TSGs (NCTSGs) were identified in goat testis. GO enrichment analyses suggested that the HCTSGs and MCTSGs has a more important association with male reproduction than NCTSGs. Additionally, we identified 644 ASE genes, including 88 tissue-specific ASE (TS-ASE) genes (e.g., FSIP2, TDRD9). GO enrichment analyses indicated that both ASE genes and TS-ASE genes were associated with goat male reproduction. Overall, this study revealed an extensive gene set involved in the regulation of male goat reproduction and their dynamic transcription patterns. Data reported here provide valuable insights for a further improvement of the economic benefits of goats as well as future treatments for male infertility.

Semen proteomics reveals alterations in fertility-related proteins post-recovery from COVID-19.

Introduction: Changes to sperm quality and decline in reproductive function have been reported in COVID-19-recovered males. Further, the emergence of SARS-CoV-2 variants has caused the resurgences of COVID-19 cases globally during the last 2years. These variants show increased infectivity and transmission along with immune escape mechanisms, which threaten the already burdened healthcare system. However, whether COVID-19 variants induce an effect on the male reproductive system even after recovery remains elusive. Methods: We used mass-spectrometry-based proteomics approaches to understand the post-COVID-19 effect on reproductive health in men using semen samples post-recovery from COVID-19. The samples were collected between late 2020 (1st wave, n = 20), and early-to-mid 2021 (2nd wave, n = 21); control samples were included (n = 10). During the 1st wave alpha variant was prevalent in India, whereas the delta variant dominated the second wave. Results: On comparing the COVID-19-recovered patients from the two waves with control samples, using one-way ANOVA, we identified 69 significantly dysregulated proteins among the three groups. Indeed, this was also reflected by the changes in sperm count, morphology, and motility of the COVID-19- recovered patients. In addition, the pathway enrichment analysis showed that the regulated exocytosis, neutrophil degranulation, antibacterial immune response, spermatogenesis, spermatid development, regulation of extracellular matrix organization, regulation of peptidase activity, and regulations of calcium ion transport were significantly dysregulated. These pathways directly or indirectly affect sperm parameters and function. Our study provides a comprehensive landscape of expression trends of semen proteins related to male fertility in men recovering from COVID-19. Discussion: Our study suggests that the effect of COVID-19 on the male reproductive system persists even after recovery from COVID-19. In addition, these post-COVID-19 complications persist irrespective of the prevalent variants or vaccination status.

Mono-(2-ethylhexyl) phthalate (MEHP) reversibly disrupts the blood-testis barrier (BTB) in pubertal rats.

The blood-testis barrier (BTB) is constituted by tight junctions between adjacent Sertoli cells (SC) that create a specialized adluminal microenvironment to foster the development of spermatocytes and spermatids. The BTB is a well-studied target of numerous environmental toxicants, including di-(2-ethylhexyl) phthalate (DEHP), a compound widely used in various consumer products. MEHP is the active toxic metabolite of DEHP that has long been recognized in postnatal rodents to disrupt SC function. This study evaluates the impact of MEHP on the integrity of the BTB in both pubertal and adult rats and the signal transduction pathways known to be involved in the disruption of the BTB. Treatment of prepubertal rats with 700 mg/kg MEHP for 24 hours functionally disrupted the BTB integrity. A similar treatment of adult rats with MEHP did not disrupt the integrity of the BTB. The observed disruption of the BTB integrity in the MEHP-treated prepubertal rats occurred concomitantly with a decreased expression and mislocalization of both the ZO1 and occludin tight junction-associated proteins, as well as sloughing of spermatocytes and spermatids. At this same time, MEHP treatment induced a transient surge of p44/42 mitogen-activated protein kinase (MAPK) pathway. Interestingly, after a recovery period of 5 weeks, the BTB recovered and was functionally intact. This is the first report to indicate that acute MEHP exposure of prepubertal rats, but not adult rats, disrupts the functional integrity of the BTB and that this effect on the BTB is reversible.

Structure and molecular basis of spermatid elongation in theDrosophilatestis

Spermatid elongation is a crucial event in the late stage of spermatogenesis in theDrosophilatestis, eventually leading to the formation of mature sperm after meiosis. During spermatogenesis, significant structural and morphological changes take place in a cluster of post-meiotic germ cells, which are enclosed in a microenvironment surrounded by somatic cyst cells. Microtubule-based axoneme assembly, formation of individualization complexes and mitochondria maintenance are key processes involved in the differentiation of elongated spermatids. They provide important structural foundations for accessing male fertility. How these structures are constructed and maintained are basic questions in theDrosophilatestis. Although the roles of several genes in different structures during the development of elongated spermatids have been elucidated, the relationships between them have not been widely studied. In addition, the genetic basis of spermatid elongation and the regulatory mechanisms involved have not been thoroughly investigated. In the present review, we focus on current knowledge with regard to spermatid axoneme assembly, individualization complex and mitochondria maintenance. We also touch upon promising directions for future research to unravel the underlying mechanisms of spermatid elongation in theDrosophilatestis.

Integrated molecular-network analysis reveals infertility-associated key genes and transcription factors in the non-obstructive azoospermia

BackgroundMale infertility is a multifactorial reproductive health problem with complex causes. Non-obstructive azoospermia (NOA) is characterized by failure of spermatogenesis, leading to the absence of spermatozoa in ejaculates. The molecular mechanism underlying the NOA is still not well understood. ObjectivesThis study aims to identify the key genes involved in male infertility that could be a potential biomarker in the diagnosis and prognosis of azoospermia. Study designThe microarray expression profiles dataset GSE45885 and GSE45887 were downloaded from the NCBI's Gene Expression Omnibus (GEO) database and analyzed for male infertility-associated differentially expressed genes (DEGs) using the GEO2R tool. The common DEGs between the two datasets were combined and their protein–protein interaction (PPI) network was constructed using Cytoscape to reveal the hub genes by topology and module analysis. In addition, transcription factors (TFs) and protein kinases regulating the hub genes were identified using the X2K tool. Then, the expression of the hub genes was validated by analyzing the GSE190752 microarray dataset. Further, the PPI network was screened for biological roles and enriched pathways using DAVID software. ResultsAbout 256 DEGs associated with NOA were identified and constructed the PPI network to find the infertility-associated proteins. The biological processes linked with these proteins were spermatogenesis, cell differentiation, flagellated sperm motility, and spermatid development. The topology and module analysis of the infertility-associated protein network identified the hub genes TEX38, FAM71F, PRR30, FAM166A, LYZL6, TPPP2, ARMC12, SPACA4, and FAM205A, which were found to be upregulated in the non-obstructive azoospermia. In addition, a total of 23 transcription factors and 3 protein kinases that are regulating these key hub genes were identified. Further these hub genes expression was validated using the microarray data and found that their expression was increased in the testicular biopsies obtained from NOA subjects, compared to healthy individuals. ConclusionThe identified key genes and its associated transcription factors are known to regulate the infertility-related processes in the non-obstructive azoospermia. Also, the clinical sample-based microarray data validation for the expression of these key hub genes indicates their potentiality to develop them as diagnostic or prognostic biomarkers for NOA.

Evaluation of toxicity and mutagenicity of oxaliplatin on germ cells in an alternative in vivo model Caenorhabditis elegans.

The platinum compound oxaliplatin is a widely used chemotherapeutic drug that shows a broad spectrum of activity in various human tumors. While the treatment-related side effects of oxaliplatin on directly treated individuals have been well-documented, little is known about the influence of oxaliplatin on germ cells and non-exposed progenies. Here we investigated the reproductive toxicity of oxaliplatin in a 3R-compliant in vivo model Caenorhabditis elegans, and evaluated the germ cell mutagenicity of oxaliplatin by using whole genome sequencing. Our results indicated that oxaliplatin treatment significantly disrupts development of spermatids and oocytes. By treating parental worms with oxaliplatin for three successive generations, sequencing data unveiled the mutagenic effects of oxaliplatin on germ cells. Analysis of genome-wide mutation spectra showed the preferentially induction of indels by oxaliplatin. In addition, we uncovered the involvement of translesion synthesis polymerase ζ in modulating mutagenic effects of oxaliplatin. These findings suggest that germ cell mutagenicity is worthy of consideration for the health risk assessment of chemotherapeutic drugs, while the combined use of alternative in vivo models and next generation sequencing technology appears to be a promising way for the preliminary safety assessment of various drugs.

Steps of spermiogenesis in the ostrich (Struthio camelus).

Few studies describe the sequence of morphological events that characterize spermiogenesis in birds. In this paper, the clearly observable steps of spermiogenesis are described and illustrated for the first time in a commercially important ratite, the ostrich, based on light microscopy of toluidine blue-stained plastic sections. Findings were supplemented and supported by ultrastructural observations, PNA labeling of acrosome development, and immunocytochemical labeling of isolated spermatogenic cells. Spermiogenesis in the ostrich followed the general pattern described in non-passerine birds. Eight steps were identified based on changes in nuclear shape and contents, positioning of the centriolar complex, and acrosome development. Only two steps could be recognized with certainty during development of the round spermatid which contributed to the fewer steps recorded for the ostrich compared to that described in some other bird species. The only lectin that displayed acrosome reactivity was PNA and only for the first three steps of spermiogenesis. This suggests that organizational and/or compositional changes may occur in the acrosome during development and merits further investigation. Immunological labeling provided additional evidence to support the finding of previous studies that the tip of the nucleus in the ostrich is shaped by the forming acrosome and not by the microtubular manchette. To our knowledge, this is the first complete description of spermiogenesis in ostrich and one of few in any avian species. In addition to comparative reproduction and animal science, this work has implications for evolutionary biology as the reported germ cell features provide a bridge between reptile and ratite-avian spermatogenesis.

ADAD1 is required for normal translation of nuclear pore and transport protein transcripts in spermatids of Mus musculus†.

ADAD1 is a testis-specific RNA-binding protein expressed in post-meiotic spermatids whose loss leads to defective sperm and male infertility. However, the drivers of the Adad1 phenotype remain unclear. Morphological and functional analysis of Adad1 mutant sperm showed defective DNA compaction, abnormal head shaping, and reduced motility. Mutant testes demonstrated minimal transcriptome changes; however, ribosome association of many transcripts was reduced, suggesting ADAD1 may be required for their translational activation. Further, immunofluorescence of proteins encoded by select transcripts showed delayed protein accumulation. Additional analyses demonstrated impaired subcellular localization of multiple proteins, suggesting protein transport is also abnormal in Adad1 mutants. To clarify the mechanism giving rise to this, the manchette, a protein transport microtubule network, and the LINC (linker of nucleoskeleton and cytoskeleton) complex, which connects the manchette to the nuclear lamin, were assessed across spermatid development. Proteins of both displayed delayed translation and/or localization in mutant spermatids implicating ADAD1 in their regulation, even in the absence of altered ribosome association. Finally, ADAD1's impact on the NPC (nuclear pore complex), a regulator of both the manchette and the LINC complex, was examined. Reduced ribosome association of NPC encoding transcripts and reduced NPC protein abundance along with abnormal localization in Adad1 mutants confirmed ADAD1's impact on translation is required for a NPC in post-meiotic germ cells. Together, these studies lead to a model whereby ADAD1's influence on nuclear transport leads to deregulation of the LINC complex and the manchette, ultimately generating the range of physiological defects observed in the Adad1 phenotype.

P-079 Transcriptomic Analysis of Seminal Plasma in NOA Men as a Predictor of Successful Testicular Sperm Extraction

Abstract Study question Could transcriptomic profiling of semen ejaculate be used to predict successful testicular sperm retrieval for men with idiopathic non-obstructive azoospermia (iNOA)? Summary answer Transcriptomic analysis of seminal plasma RNA in iNOA men revealed gene imbalances that consistently correlated with the success of retrieving spermatozoa via a testicular biopsy. What is known already Although microdissection testicular sperm extraction (m-TESE) in NOA men results in successful spermatozoa retrieval in about 60% of the cases, it is difficult to predict which cases will fail to recover sperm. While several algorithms have been proposed to make this prediction, such as age, serum FSH, inhibin B, and genetics, there is no one factor that can do so reliably. Even histopathology fails to be more accurate, and it is equally invasive. Recently, epigenetic analysis on testicular biopsy specimens has shown a differential gene expression in relation to the origin of azoospermia and spermatogenic function. Study design, size, duration Over a 3-year period, 23 men diagnosed with iNOA underwent repeated extensive semen analyses and were deemed azoospermic. These patients were categorized based on whether spermatozoa were subsequently retrieved (+Sperm) or not (-Sperm) at micro-TESE. Transcriptomic analysis was performed by RNAseq, and significant differentially expressed gene (DEG) profiles were assessed and compared between the two cohorts. DNAseq was then used to confirm our findings. Participants/materials, setting, methods RNA and DNA were isolated from seminal plasma using a commercially available spin column kit and sequenced by Illumina HiSeq 3000/4000 platform at 2x150bp. Transcriptomic profiling was carried out in comparison to a fertile donor control and among the two cohorts. An absolute log2fold change of > 1 and a P-value of < 0.0005 were considered statistically significant. Main results and the role of chance Transcriptomic analyses of ejaculates from 23 azoospermic men were assessed for a total of 21,855 genes against a fertile donor control. Subsequently, 11/23 (47.8%) men (39.0±12yrs) underwent successful testicular sperm retrievals. Their DEG profiles revealed 1,409 imbalanced genes. However, 13 were consistently imbalanced among them: 8 involved in spermatogenesis and 5 in sperm function. Alternatively, for the 12 men in the –Sperm cohort (34.3±5yrs), 1,265 imbalanced genes were identified with 12 common imbalanced genes associated with spermatogenesis (n = 5), sperm function (n = 3), sperm maturation (n = 1), and cell cycle regulation (n = 3). When comparing the DEG profiles between the + and –Sperm cohorts, 8 commonly shared imbalanced genes were identified. IGSF11-AS1, a gene expressed in the testis and implicated in spermatid development, was consistently underexpressed in all –Sperm men. TPTE2, a testis-specific gene regulating spermatogenesis, was overexpressed in 81.8% (9/11) of the individuals in the +Sperm cohort and conversely underexpressed in the -Sperm group. Most interestingly, NEU1, involved in acrosome development and fertilization, was consistently overexpressed in all individuals of the +Sperm group, yet clearly underexpressed in the entire –Sperm group. DNAseq showed that the NEU1 gene exhibited a synonymous mutation for the +Sperm group and a frameshift mutation in the –Sperm group. Limitations, reasons for caution Using noninvasive RNAseq and DNAseq on the seminal plasma has allowed us to identify DEGs that may be used to predict whether a patient with iNOA will have a successful or failed retrieval with micro-TESE. However, these results are preliminary and should be further validated in a larger study cohort. Wider implications of the findings Transcriptomics on the ejaculates of men with iNOA represents a noninvasive tool to detect the presence of residual spermatogenesis. Once confirmed, these findings may help guide patients in weighing their exposure to anesthesia and surgical risks. This would help to mitigate patient emotional and financial distress. Trial registration number N/A

The PIWI-specific insertion module helps load longer piRNAs for translational activation essential for male fertility.

PIWI-clade proteins harness piRNAs of 24-33 nt in length. Of great puzzles are how PIWI-clade proteins incorporate piRNAs of different sizes and whether the size matters to PIWI/piRNA function. Here we report that a PIWI-Ins module unique in PIWI-clade proteins helps define the length of piRNAs. Deletion of PIWI-Ins in Miwi shifts MIWI to load with shorter piRNAs and causes spermiogenic failure in mice, demonstrating the functional importance of this regulatory module. Mechanistically, we show that longer piRNAs provide additional complementarity to target mRNAs, thereby enhancing the assembly of the MIWI/eIF3f/HuR super-complex for translational activation. Importantly, we identify a c.1108C>T (p.R370W) mutation of HIWI (human PIWIL1) in infertile men and demonstrate in Miwi knock-in mice that this genetic mutation impairs male fertility by altering the property of PIWI-Ins in selecting longer piRNAs. These findings reveal a critical role of PIWI-Ins-ensured longer piRNAs in fine-tuning MIWI/piRNA targeting capacity, proven essential for spermatid development and male fertility.

Broad phosphorylation mediated by testis-specific serine/threonine kinases contributes to spermiogenesis and male fertility

Genetic studies elucidate a link between testis-specific serine/threonine kinases (TSSKs) and male infertility in mammals, but the underlying mechanisms are unclear. Here, we identify a TSSK homolog in Drosophila, CG14305 (termed dTSSK), whose mutation impairs the histone-to-protamine transition during spermiogenesis and causes multiple phenotypic defects in nuclear shaping, DNA condensation, and flagellar organization in spermatids. Genetic analysis demonstrates that kinase catalytic activity of dTSSK, which is functionally conserved with human TSSKs, is essential for male fertility. Phosphoproteomics identify 828 phosphopeptides/449 proteins as potential substrates of dTSSK enriched primarily in microtubule-based processes, flagellar organization and mobility, and spermatid differentiation and development, suggesting that dTSSK phosphorylates various proteins to orchestrate postmeiotic spermiogenesis. Among them, the two substrates, protamine-like protein Mst77F/Ser9 and transition protein Mst33A/Ser237, are biochemically validated to be phosphorylated by dTSSK in vitro, and are genetically demonstrated to be involved in spermiogenesis in vivo. Collectively, our findings demonstrate that broad phosphorylation mediated by TSSKs plays an indispensable role in spermiogenesis.

A single-cell landscape of triptolide-associated testicular toxicity in mice

Triptolide is a key active component of the widely used traditional Chinese herb medicine Tripterygium wilfordii Hook. F. Although triptolide exerts multiple biological activities and shows promising efficacy in treating inflammatory-related diseases, its well-known safety issues, especially reproductive toxicity has aroused concerns. However, a comprehensive dissection of triptolide-associated testicular toxicity at single cell resolution is still lacking. Here, we observed testicular toxicity after 14 days of triptolide exposure, and then constructed a single-cell transcriptome map of 59,127 cells in mouse testes upon triptolide-treatment. We identified triptolide-associated shared and cell-type specific differentially expressed genes, enriched pathways, and ligand-receptor pairs in different cell types of mouse testes. In addition to the loss of germ cells, our results revealed increased macrophages and the inflammatory response in triptolide-treated mouse testes, suggesting a critical role of inflammation in triptolide-induced testicular injury. We also found increased reactive oxygen species (ROS) signaling and downregulated pathways associated with spermatid development in somatic cells, especially Leydig and Sertoli cells, in triptolide-treated mice, indicating that dysregulation of these signaling pathways may contribute to triptolide-induced testicular toxicity. Overall, our high-resolution single-cell landscape offers comprehensive information regarding triptolide-associated gene expression profiles in major cell types of mouse testes at single cell resolution, providing an invaluable resource for understanding the underlying mechanism of triptolide-associated testicular injury and additional discoveries of therapeutic targets of triptolide-induced male reproductive toxicity.