Sperm Proteome Analysis and Identification of Fertility-Associated Biomarkers in Unexplained Male Infertility

Cryopreservation of highly extended pig spermatozoa remodels its proteome and counteracts polyspermic fertilization in vitro

BACKGROUND

Currently, high polyspermy remains a significant obstacle to achieving optimal efficiency in in vitro fertilization (IVF) and in vitro embryo production (IVP) systems in pigs. Developing strategies that would prevent polyspermy is essential in overcoming this challenge and maximizing the potential of this reproductive biotechnology. Previous results have demonstrated that using boar spermatozoa subjected to a high-extension and reconcentration procedure and then cryopreserved resulted in significant improvements in IVF/IVP systems with high rates of monospermy and penetration.

OBJECTIVE

The aim of the present study was to unveil the molecular mechanisms that may underlie the changes in fertilization patterns exhibited by highly extended and cryopreserved boar spermatozoa.

MATERIALS AND METHODS

To achieve this goal, we used quantitative proteomic analysis (LC‒ESI‒MS/MS SWATH) to identify differentially abundant proteins (DAPs) between highly extended (HE) and conventionally (control; CT) cryopreserved boar spermatozoa. Prior to the analysis, we evaluated the in vitro post-thawing fertilizing ability of the sperm samples. The results demonstrated a remarkable improvement in monospermy and IVF efficiency when using HE spermatozoa in IVF compared with CT spermatozoa.

RESULTS

At the proteomic level, the combination of high-extension and cryopreservation had a significant impact on the frozen-thawed sperm proteome. A total of 45 proteins (24 downregulated and 21 upregulated) were identified as DAPs (FC > 1 or ≤1; p < 0.05) when compared with CT spermatozoa. Some of these proteins were primarily linked to metabolic processes and the structural composition of sperm cells. The dysregulation of these proteins may have a direct or indirect effect on essential sperm functions and significantly affect spermatozoa-oocyte interaction and, therefore, the sperm fertilization profile under in vitro conditions. While these findings are promising, further research is necessary to comprehend how the disturbance of specific proteins affects sperm fertilization ability.

Analysis of histomorphology and SERNINA5 gene expression in different regions of epididymis of cattleyak

The molecular mechanism of sterility in cattleyak is still unresolved. The related factors of infertility in cattleyak were studied by tissue section, SERPINA5 gene cloning and bioinformatics technology. Tissue sections of the epididymis showed poorly structured and disorganized epithelial cells in the corpus of the epididymis compared to the caput of the epididymis, while in the cauda part of the epididymis, the extra basal smooth muscle was thinner, the surface of the epithelial lumen was discontinuous and the epithelium was markedly degenerated. The results of gene cloning showed that the coding sequence (CDS) region of the SERPINA5 gene in cattleyak was 1215 bp in length, encoding a total of 404 amino acids, of which the isoleucine content was the highest, accounting for a total of 49 amino acids (12.1%). The results of real-time fluorescence quantitative PCR (qPCR) showed that the expression of the SERPINA5 gene in the epididymis caput in cattleyak was significantly higher than that in the corpus and cauda (P < 0.05), but there were no significant differences between the corpus and cauda. In the current study, histological and bioinformatics analysis, physicochemical properties, and the expression analysis of the SERPINA5 gene in different regions of the epididymis in cattleyak were carried out to explore the biological complications of cattleyak infertility.

Seminal plasma proteomics as putative biomarkers for male infertility diagnosis

Male infertility represents a significant global public health issue that is currently emerging as a prominent research focus. Presently, laboratories adhere to the guidelines outlined by the World Health Organization (WHO) manuals for conducting routine semen analysis to diagnose male infertility. However, the accuracy of results in predicting sperm quality and fertility is limited because some individuals with a normal semen analysis report, an unremarkable medical history, and a physical examination may still experience infertility. As a result, the importance of employing more advanced techniques to investigate sperm function and male fertility in the treatment of male infertility and/or subfertility becomes apparent. The standard test for evaluating human semen has been improved by more complex tests that look at things like reactive oxygen species (ROS) levels, total antioxidant capacity (TAC), sperm DNA fragmentation levels, DNA compaction, apoptosis, genetic testing, and the presence and location of anti-sperm antibodies. Recent discoveries of novel biomarkers have significantly enriched our understanding of male fertility. Moreover, the notable biological diversity among samples obtained from the same individual complicates the efficacy of routine semen analysis. Therefore, unraveling the molecular mechanisms involved in fertilization is pivotal in expanding our understanding of factors contributing to male infertility. By understanding how these proteins work and what role they play in sperm activity, we can look at the expression profile in men who can't have children to find diagnostic biomarkers. This review examines the various sperm and seminal plasma proteins associated with infertility, as well as proteins that are either deficient or exhibit aberrant expression, potentially contributing to male infertility causes.

Association of histidine-rich glycoprotein C633T single nucleotide polymorphism and recurrent miscarriage in Iranian women

BACKGROUND

Recurrent miscarriage (RM) is defined as the occurrence of at least two or three subsequent miscarriages within the 20th -24th weeks of pregnancy. The primary objective of this study was to investigate whether histidine-rich glycoprotein C633T single nucleotide polymorphism (HRG C633T SNP) statistically correlates with the occurrence of RM among Iranian women.

METHODS AND RESULTS

Blood samples from 200 women were taken at the outset of the study. Then, the blood samples of 100 women who had a record of RM (case group) were compared with the other 100 women's blood samples who had no record of RM (control group). Following DNA extraction, the polymorphism of histidine-rich glycoprotein C633T (HRG C633T) for every case was specified and all women were genotyped by the amplification-refractory mutation system (ARMS) method. The results of the study revealed that there was a statistically significant difference between T/T genotype (OR = 3.5, CI (1.39-8.77), p = 0.007), and C/T genotype (OR = 1.83, CI (0.99-3.37), p = 0.05) in the case and control groups. Also, a statistically significant association was observed in T allelic frequency in the RM participants compared to the control group (OR = 2.01, CI (1.31-3.09), p = 0.01).

CONCLUSIONS

The present study determined that there was a statistically significant relationship between HRG C633T SNP and increased RM regarding allelic and genotypical aspects. Moreover, it became apparent that women with homozygous T/T genotype were more susceptible to the risk of RM.

Cancer risk and male Infertility: Unravelling predictive biomarkers and prognostic indicators

In recent years, there has been a global increase in cases of male infertility. There are about 30 million cases of male infertility worldwide and male reproductive health is showing rapid decline in last few decades. It is now recognized as a potential risk factor for developing certain types of cancer, particularly genitourinary malignancies like testicular and prostate cancer. Male infertility is considered a potential indicator of overall health and an early biomarker for cancer. Cases of unexplained male factor infertility have high levels of oxidative stress and oxidative DNA damage and this induces both denovo germ line mutations and epimutations due to build up of 8-hydroxy 2 deoxygunaosine abase which is highly mutagenic and also induces hypomethylation and genomic instability. Consequently, there is growing evidence to explore the various factors contributing to an increased cancer risk. Currently, the available prognostic and predictive biomarkers associated with semen characteristics and cancer risk are limited but gaining significant attention in clinical research for the diagnosis and treatment of elevated cancer risk in the individual and in offspring. The male germ cell being transcriptionally and translationally inert has a highly truncated repair mechanism and has minimal antioxidants and thus most vulnerable to oxidative injury due to environmental factors and unhealthy lifestyle and social habits. Therefore, advancing our understanding requires a thorough evaluation of the pathophysiologic mechanisms at the DNA, RNA, protein, and metabolite levels to identify key biomarkers that may underlie the pathogenesis of male infertility and associated cancer. Advanced methodologies such as genomics, epigenetics, proteomics, transcriptomics, and metabolomics stand at the forefront of cutting-edge approaches for discovering novel biomarkers, spanning from infertility to associated cancer types. Henceforth, in this review, we aim to assess the role and potential of recently identified predictive and prognostic biomarkers, offering insights into the success of assisted reproductive technologies, causes of azoospermia and idiopathic infertility, the impact of integrated holistic approach and lifestyle modifications, and the monitoring of cancer susceptibility, initiation and progression. Comprehending these biomarkers is crucial for providing comprehensive counselling to infertile men and cancer patients, along with their families.

Proteomic Insights into Seminal Plasma and Spermatozoa Proteins of Small-Spotted Catsharks, Scyliorhinus canicula: Implications for Reproductive Conservation in Aquariums

In the ex situ conservation of chondrichthyan species, successful reproduction in aquaria is essential. However, these species often exhibit reduced reproductive success under human care. A key aspect is that conventional sperm analyses do not provide insights into the functional competence of sperm. However, proteomics analysis enables a better understanding of male physiology, gaining relevance as a powerful tool for discovering protein biomarkers related to fertility. The present work aims to build the first proteome database for shark semen and to investigate the proteomic profiles of seminal plasma and spermatozoa from small-spotted catsharks (Scyliorhinus canicula) related to the underlying adaptations to both natural and aquarium environments, thereby identifying the reproductive impact in aquarium specimens. A total of 305 seminal plasma and 535 spermatozoa proteins were identified. Among these, 89 proteins (29.2% of the seminal plasma set) were common to both spermatozoa and seminal plasma. In the seminal plasma, only adenosylhomocysteinase protein showed differential abundance (DAP) between wild and aquarium animals. With respect to the spermatozoa proteins, a total of 107 DAPs were found between groups. Gene Ontology enrichment analysis highlighted the primary functional roles of these DAPs involved in oxidoreductase activity. Additionally, KEGG analysis indicated that these DAPs were primarily associated with metabolic pathways and carbon metabolism. In conclusion, we have successfully generated an initial proteome database for S. canicula seminal plasma and spermatozoa. Furthermore, we have identified protein variations, predominantly within spermatozoa, between aquarium and wild populations of S. canicula. These findings provide a foundation for future biomarker discovery in shark reproduction studies. However, additional research is required to determine whether these protein variations correlate with reproductive declines in captive sharks.

Bringing proteomics to bear on male fertility: key lessons

INTRODUCTION

Male infertility is a major public health concern globally. Proteomics has revolutionized our comprehension of male fertility by identifying potential infertility biomarkers and reproductive defects. Studies comparing sperm proteome with other male reproductive tissues have the potential to refine fertility diagnostics and guide infertility treatment development.

AREAS COVERED

This review encapsulates literature using proteomic approaches to progress male reproductive biology. Our search methodology included systematic searches of databases such as PubMed, Scopus, and Web of Science for articles up to 2023. Keywords used included 'male fertility proteomics,' 'spermatozoa proteome,' 'testis proteomics,' 'epididymal proteomics,' and 'non-hormonal male contraception.' Inclusion criteria were robust experimental design, significant contributions to male fertility, and novel use of proteomic technologies.

EXPERT OPINION

Expert analysis shows a shift from traditional research to an integrative approach that clarifies male reproductive health's molecular intricacies. A gap exists between proteomic discoveries and clinical application. The expert opinions consolidated here not only navigate the current findings but also chart the future proteomic applications for scientific and clinical breakthroughs. We underscore the need for continued investment in proteomic research - both in the technological and collaborative arenas - to further unravel the secrets of male fertility, which will be central to resolving fertility issues in the coming era.

Proteomics of human spermatozoa

Proteomic methodologies offer a robust approach to identify and quantify thousands of proteins from semen components in both fertile donors and infertile patients. These strategies provide an unprecedented discovery potential, which many research teams are currently exploiting. However, it is essential to follow a suitable experimental design to generate robust data, including proper purification of samples, appropriate technical procedures to increase identification throughput, and data analysis following quality criteria. More than 6000 proteins have been described so far through proteomic analyses in the mature sperm cell, increasing our knowledge on processes involved in sperm function, intercommunication between spermatozoa and seminal fluid, and the transcriptional origin of the proteins. These data have been complemented with comparative studies to ascertain the potential role of the identified proteins on sperm maturation and functionality, and its impact on infertility. By comparing sperm protein profiles, many proteins involved in the acquisition of fertilizing ability have been identified. Furthermore, altered abundance of specific protein groups has been observed in a wide range of infertile phenotypes, including asthenozoospermia, oligozoospermia, and normozoospermia with unsuccessful assisted reproductive techniques outcomes, leading to the identification of potential clinically useful protein biomarkers. Finally, proteomics has been used to evaluate alterations derived from semen sample processing, which might have an impact on fertility treatments. However, the intrinsic heterogeneity and inter-individual variability of the semen samples have resulted in a relatively low overlap among proteomic reports, highlighting the relevance of combining strategies for data validation and applying strict criteria for proteomic data analysis to obtain reliable results. This mini-review provides an overview of the most critical steps to conduct robust sperm proteomic studies, the most relevant results obtained so far, and potential next steps to increase the impact of sperm proteomic data.

The human sperm proteome-Toward a panel for male fertility testing

BACKGROUND

Although male factor accounts for 40%-50% of unintended childlessness, we are far from fully understanding the detailed causes. Usually, affected men cannot even be provided with a molecular diagnosis.

OBJECTIVES

We aimed at a higher resolution of the human sperm proteome for better understanding of the molecular causes of male infertility. We were particularly interested in why reduced sperm count decreases fertility despite many normal-looking spermatozoa and which proteins might be involved.

MATERIAL AND METHODS

Applying mass spectrometry analysis, we qualitatively and quantitatively examined the proteomic profiles of spermatozoa from 76 men differing in fertility. Infertile men had abnormal semen parameters and were involuntarily childless. Fertile subjects exhibited normozoospermia and had fathered children without medical assistance.

RESULTS

We discovered proteins from about 7000 coding genes in the human sperm proteome. These were mainly known for involvements in cellular motility, response to stimuli, adhesion, and reproduction. Numbers of sperm proteins showing at least threefold deviating abundances increased from oligozoospermia (N = 153) and oligoasthenozoospermia (N = 154) to oligoasthenoteratozoospermia (N = 368). Deregulated sperm proteins primarily engaged in flagellar assembly and sperm motility, fertilization, and male gametogenesis. Most of these participated in a larger network of male infertility genes and proteins.

DISCUSSION

We expose 31 sperm proteins displaying deviant abundances under infertility, which already were known before to have fertility relevance, including ACTL9, CCIN, CFAP47, CFAP65, CFAP251 (WDR66), DNAH1, and SPEM1. We propose 18 additional sperm proteins with at least eightfold differential abundance for further testing of their diagnostic potential, such as C2orf16, CYLC1, SPATA31E1, SPATA31D1, SPATA48, EFHB (CFAP21), and FAM161A.

CONCLUSION

Our results shed light on the molecular background of the dysfunctionality of the fewer spermatozoa produced in oligozoospermia and syndromes including it. The male infertility network presented may prove useful in further elucidating the molecular mechanism of male infertility.

New Insights on Sperm Function in Male Infertility of Unknown Origin: A Multimodal Approach

The global trend of rising (male) infertility is concerning, and the unidentifiable causes in half of the cases, the so-called unknown origin male infertility (UOMI), demands a better understanding and assessment of both external/internal factors and mechanisms potentially involved. In this work, it was our aim to obtain new insight on UOMI, specifically on idiopathic (ID) and Unexplained male infertility (UMI), relying on a detailed evaluation of the male gamete, including functional, metabolic and proteomic aspects. For this purpose, 1114 semen samples, from males in couples seeking infertility treatment, were collected at the Reproductive Medicine Unit from the Centro Hospitalar e Universitário de Coimbra (CHUC), from July 2018-July 2022. Based on the couples' clinical data, seminal/hormonal analysis, and strict eligibility criteria, samples were categorized in 3 groups, control (CTRL), ID and UMI. Lifestyle factors and anxiety/depression symptoms were assessed via survey. Sperm samples were evaluated functionally, mitochondrially and using proteomics. The results of Assisted Reproduction Techniques were assessed whenever available. According to our results, ID patients presented the worst sperm functional profile, while UMI patients were similar to controls. The proteomic analysis revealed 145 differentially expressed proteins, 8 of which were specifically altered in ID and UMI samples. Acrosin (ACRO) and sperm acrosome membrane-associated protein 4 (SACA4) were downregulated in ID patients while laminin subunit beta-2 (LAMB2), mannose 6-phosphate isomerase (MPI), ATP-dependent 6-phosphofructokinase liver type (PFKAL), STAR domain-containing protein 10 (STA10), serotransferrin (TRFE) and exportin-2 (XPO2) were downregulated in UMI patients. Using random forest analysis, SACA4 and LAMB2 were identified as the sperm proteins with a higher chance of distinguishing ID and UMI patients, and their function and expression variation were in accordance with the functional results. No alterations were observed in terms of lifestyle and psychological factors among the 3 groups. These findings obtained in an experimental setting based on 3 well-defined groups of subjects, might help to validate new biomarkers for unknown origin male infertility (ID and UMI) that, in the future, can be used to improve diagnostics and treatments.

Seminal plasma untargeted metabolomic and lipidomic profiling for the identification of a novel panel of biomarkers and therapeutic targets related to male infertility

Male infertility occurs approximately in about 50% of all infertility cases and represents a serious concern worldwide. Traditional semen analysis alone is insufficient to diagnose male infertility. Over the past two decades, advances in omics technologies have led to the widespread application of metabolomics profiling as a valuable diagnostic tool for various diseases and disorders. Seminal plasma represents a rich and easily accessible source of metabolites surrounding spermatozoa, a milieu that provides several indispensable nutrients to sustain sperm motility and fertilization. Changes of metabolic profiles in seminal plasma reflect male reproductive tract disorders. Here, we performed seminal plasma metabolomics and lipidomics profiling to identify a new pattern of biomarkers of male infertility. Seminal plasma samples from unfertile subjects (n = 31) and fertile controls (n = 19) were analyzed using an untargeted metabolomics/lipidomics integrated approach, based on Ultra-High-Pressure Liquid Chromatography-tandem Mass Spectrometry. Partial Least Squares-Discriminant Analysis showed a distinct separation between healthy fertile men and infertile subjects. Among the 15 selected candidate biomarkers based on Variable Importance in Projection scores, phosphatidylethanolamine (PE) (18:1; 18:1) resulted with the highest score. In total, 40 molecular species showed statistically significant variations between fertile and infertile men. Heat-map and volcano plot analysis indicated that acylcarnitines, phosphatidylserine (PS) (40:2) and lactate were decreased, while PE (18:1; 18:1), Phosphatidic acid (PA) (O-19:2; 18:1), Lysophosphatidylethanolamine (LPE) (O-16:1) and Phosphatidylcholine (PC) (O-16:2; 18:1)-CH3 were increased in the infertile group. The present study is the first one to analyze the metabolomics/lipidomics dysregulation in seminal plasma between fertile and infertile individuals regardless of sub-infertility condition. Association of several metabolites/lipids dysregulation with male infertility reinforced data of previous studies performed with different approaches. In particular, we confirmed significantly decreased levels of PS and carnitines in infertile patients as well as the positive correlation with sperm motility and morphology. If validated on a larger prospective cohort, the metabolite biomarkers of infertility in seminal plasma we identified in the present study might inform novel strategies for diagnosis and interventions to overcome male infertility.

Mapping the human sperm proteome - novel insights into reproductive research

INTRODUCTION

Spermatozoa are highly specialized cells with unique morphology. In addition, spermatozoa lose a considerable amount of cytoplasm during spermiogenesis, when they also compact their DNA, resulting in a transcriptionally quiescent cell. Throughout the male reproductive tract, sperm will acquire proteins that enable them to interact with the female reproductive tract. After ejaculation, proteins undergo post-translational modifications for sperm to capacitate, hyperactivate and fertilize the oocyte. Many proteins have been identified as predictors of male infertility, and also investigated in diseases that compromise reproductive potential.

AREAS COVERED

In this review we proposed to summarize the recent findings about the sperm proteome and how they affect sperm structure, function, and fertility. A literature search was performed using PubMed and Google Scholar databases within the past 5 years until August 2022.

EXPERT OPINION

Sperm function depends on protein abundance, conformation, and PTMs; understanding the sperm proteome may help to identify pathways essential to fertility, even making it possible to unravel the mechanisms involved in idiopathic infertility. In addition, proteomics evaluation offers knowledge regarding alterations that compromise the male reproductive potential.

Expression profiles of meiotic genes in male vs. female gonads and gametes: Insights into fertility issues

Gametes are specialized cells that, at fertilization, give rise to a totipotent zygote capable of generating an entire organism. Female and male germ cells undergo meiosis to produce mature gametes; however, sex-specific events of oogenesis and spermatogenesis contribute to specific roles of gametes in reproductive issues. We investigate the differential gene expression (DGE) of meiosis-related genes in human female and male gonads and gametes in normal and pathological conditions. The transcriptome data for the DGE analysis was obtained through the Gene Expression Omnibus repository, comprising human ovary and testicle samples of the prenatal period and adulthood, additionally to male (non-obstructive azoospermia (NOA) and teratozoospermia), and female (polycystic ovary syndrome (PCOS) and advanced maternal age) reproductive conditions. Gene ontology terms related to meiosis were associated with 678 genes, of which 17 genes in common were differentially expressed between the testicle and ovary during the prenatal period and adulthood. Except for SERPINA5 and SOX9, the 17 meiosis-related genes were downregulated in the testicle during the prenatal period and upregulated in adulthood compared to the ovary. No differences were observed in the oocytes of PCOS patients; however, meiosis-related genes were differentially expressed according to the patient’s age and maturity of the oocyte. In NOA and teratozoospermia, 145 meiosis-related genes were differentially expressed in comparison to the control, including OOEP; despite no recognized role in male reproduction, OOEP was co-expressed with genes related to male fertility. Taking together, these results shed light on potential genes that might be relevant to comprehend human fertility disorders.

Mass Spectrometry-Based Untargeted Approaches to Reveal Diagnostic Signatures of Male Infertility in Seminal Plasma: A New Laboratory Perspective for the Clinical Management of Infertility?

Male infertility has been recognized as a global health problem. Semen analysis, although considered the golden standard, may not provide a confident male infertility diagnosis alone. Hence, there is the urgent request for an innovative and reliable platform to detect biomarkers of infertility. The rapid expansion of mass spectrometry (MS) technology in the field of the 'omics' disciplines, has incredibly proved the great potential of MS-based diagnostic tests to revolutionize the future of pathology, microbiology and laboratory medicine. Despite the increasing success in the microbiology area, MS-biomarkers of male infertility currently remain a proteomic challenge. In order to address this issue, this review encompasses proteomics investigations by untargeted approaches with a special focus on experimental designs and strategies (bottom-up and top-down) for seminal fluid proteome profiling. The studies reported here witness the efforts of the scientific community to address these investigations aimed at the discovery of MS-biomarkers of male infertility. Proteomics untargeted approaches, depending on the study design, might provide a great plethora of biomarkers not only for a male infertility diagnosis, but also to address a new MS-biomarkers classification of infertility subtypes. From the early detection to the evaluation of infertility grade, new MS-derived biomarkers might also predict long-term outcomes and clinical management of infertility.

Microfluidics facilitating the use of small extracellular vesicles in innovative approaches to male infertility

Sperm are transcriptionally and translationally quiescent and, therefore, rely on the seminal plasma microenvironment for function, survival and fertilization of the oocyte in the oviduct. The male reproductive system influences sperm function via the binding and fusion of secreted epididymal (epididymosomes) and prostatic (prostasomes) small extracellular vesicles (S-EVs) that facilitate the transfer of proteins, lipids and nucleic acids to sperm. Seminal plasma S-EVs have important roles in sperm maturation, immune and oxidative stress protection, capacitation, fertilization and endometrial implantation and receptivity. Supplementing asthenozoospermic samples with normospermic-derived S-EVs can improve sperm motility and S-EV microRNAs can be used to predict non-obstructive azoospermia. Thus, S-EV influence on sperm physiology might have both therapeutic and diagnostic potential; however, the isolation of pure populations of S-EVs from bodily fluids with current conventional methods presents a substantial hurdle. Many conventional techniques lack accuracy, effectiveness, and practicality; yet microfluidic technology has the potential to simplify and improve S-EV isolation and detection.

Possible Harmful Effects of Smoking Hookah on Sperm DNA Fragmentation Index and Protamine Genes Expression in Normozoospermic Men

Objectives

In recent years, smoking water pipes or hookah has increased among adolescents in most countries. Although there is evidence in support of the negative effects of this type of smoking on human health, such as the increased risk of lung disease, little is known about the potential effects of hookah smoking on the male reproductive system, especially on the molecular aspects of sperm.

Patients and methods

This cross-sectional study examined sperm DNA fragmentation index, protamine 1 and 2 (PRM1 and PRM2) genes expression, and oxidant status in normozoospermic hookah smokers in comparison with non-smoker controls.

Results

Our results showed significantly higher rates of DNA fragmentation, protamine deficiency, and abnormal chromatin condensation in the spermatozoa of hookah smokers (P < .0001). Also, protamine gene expression showed a remarkable decrease in hookah smokers (1.55 ± 2.54 and 0.33 ± 0.54) compared to the controls (3.49 ± 5.41 and 1.22 ± 1.96), although the reduction was not statistically significant (P = .155 and P = .066, respectively). Moreover, a significantly higher level of semen MDA was observed in the case group compared to the controls (0.39 ± 1.04 vs 0.15 ± 0.21; P = .013).

Conclusion

According to our study, although hookah smoking does not have a significant effect on sperm parameters, it may have deleterious effects on DNA integrity, oxidative status, and nuclear protein levels of spermatozoa.

New horizons in human sperm selection for assisted reproduction

Male infertility is a commonly encountered pathology that is estimated to be a contributory factor in approximately 50% of couples seeking recourse to assisted reproductive technologies. Upon clinical presentation, such males are commonly subjected to conventional diagnostic andrological practices that rely on descriptive criteria to define their fertility based on the number of morphologically normal, motile spermatozoa encountered within their ejaculate. Despite the virtual ubiquitous adoption of such diagnostic practices, they are not without their limitations and accordingly, there is now increasing awareness of the importance of assessing sperm quality in order to more accurately predict a male's fertility status. This realization raises the important question of which characteristics signify a high-quality, fertilization competent sperm cell. In this review, we reflect on recent advances in our mechanistic understanding of sperm biology and function, which are contributing to a growing armory of innovative approaches to diagnose and treat male infertility. In particular we review progress toward the implementation of precision medicine; the robust clinical adoption of which in the setting of fertility, currently lags well behind that of other fields of medicine. Despite this, research shows that the application of advanced technology platforms such as whole exome sequencing and proteomic analyses hold considerable promise in optimizing outcomes for the management of male infertility by uncovering and expanding our inventory of candidate infertility biomarkers, as well as those associated with recurrent pregnancy loss. Similarly, the development of advanced imaging technologies in tandem with machine learning artificial intelligence are poised to disrupt the fertility care paradigm by advancing our understanding of the molecular and biological causes of infertility to provide novel avenues for future diagnostics and treatments.

Fertility in the aging male: a systematic review

The negative effect of advanced female age on fertility and offspring health is well understood. In comparison, much less is known about the implications of male age on fertility, with many studies showing conflicting results. Nevertheless, increasing evidence suggests that advanced paternal age has negative effects on sperm parameters, reproductive success, and offspring health. Herein, we summarize the current body of knowledge on this controversial topic, with the belief that this review will serve as a resource for the clinicians providing fertility counseling to couples with older male partners.

Exploring the main effects of phoenix dactylifera on destructive changes caused by cyclophosphamide in male reproductive system in mice

Cyclophosphamide leaves an undesirable effect on testes. This study was conducted to explore the effects of the Phoenix dactylifera (DP) on testes following the cyclophosphamide treatment. Thirty-six male mice were divided into six groups, one control, one cyclophosphamide, two groups of cyclophosphamide with a dose of 200 mg kg^-1 and a dose of 400 mg kg^-1 DP, and two of only high and low doses of DP. All groups were gavaged daily for 28 days. The animals were euthanized 24 hr after implementing the last treatment. Then, the testes and epididymis samples were removed and weighed. The main sperm characteristics such as the number of sperm and sperm viability, the morphometric changes, biochemical analysis of testes and enzyme activity were investigated. With the cyclophosphamide group, only body weight, testes weight, epididymis weight, sperm viability and the fertilization percentage were decreased significantly compared to the control group. Moreover, the spermatogenesis indices and morphometric parameters in this group indicated a significant decrease. Furthermore, the morphological changes were observed in the testicular tissue, including seminiferous tubule atrophy, vacuolation, hyperemia of blood vessels and increased space in the interstitial tissue. In the biochemical study of cyclophosphamide group, the amount of glutathione peroxidase in serum was decreased, whereas, the amount of malondialdehyde in testicular tissue showed a significant increase. The DP group included the antioxidant and anti-apoptotic properties. It seemed that the compounds in the DP would lead to the inhibition of the production of active metabolites released from the cyclophosphamide.

Infertility in Men: Advances towards a Comprehensive and Integrative Strategy for Precision Theranostics

Male infertility is an increasing and serious medical concern, though the mechanism remains poorly understood. Impaired male reproductive function affects approximately half of infertile couples worldwide. Multiple factors related to the environment, genetics, age, and comorbidities have been associated with impaired sperm function. Present-day clinicians rely primarily on standard semen analysis to diagnose male reproductive potential and develop treatment strategies. To address sperm quality assessment bias and enhance analysis accuracy, the World Health Organization (WHO) has recommended standardized sperm testing; however, conventional diagnostic and therapeutic options for male infertility, including physical examination and semen standard analysis, remain ineffective in relieving the associated social burden. Instead, assisted reproductive techniques are becoming the primary therapeutic approach. In the post-genomic era, multiomics technologies that deeply interrogate the genome, transcriptome, proteome, and/or the epigenome, even at single-cell level, besides the breakthroughs in robotic surgery, stem cell therapy, and big data, offer promises towards solving semen quality deterioration and male factor infertility. This review highlights the complex etiology of male infertility, especially the roles of lifestyle and environmental factors, and discusses advanced technologies/methodologies used in characterizing its pathophysiology. A comprehensive combination of these innovative approaches in a global and multi-centric setting and fulfilling the suitable ethical consent could ensure optimal reproductive and developmental outcomes. These combinatorial approaches should allow for the development of diagnostic markers, molecular stratification classes, and personalized treatment strategies. Since lifestyle choices and environmental factors influence male fertility, their integration in any comprehensive approach is required for safe, proactive, cost-effective, and noninvasive precision male infertility theranostics that are affordable, accessible, and facilitate couples realizing their procreation dream.

Implementing a preimplantation proteomic approach to advance assisted reproduction technologies in the framework of predictive, preventive, and personalized medicine

The evolution of the field of assisted reproduction technology (ART) in the last 40 years has significantly contributed to the management of global infertility. Despite the great numbers of live births that have been achieved through ART, there is still potential for increasing the success rates. As a result, there is a need to create optimum conditions in order to increase ART efficacy. The selection of the best sperm, oocyte, and embryo, as well as the achievement of optimal endometrial receptivity, through the contribution of new diagnostic and treatment methods, based on a personalized proteomic approach, may assist in the attainment of this goal. Proteomics represent a powerful new technological development, which seeks for protein biomarkers in human tissues. These biomarkers may aid to predict the outcome, prevent failure, and monitor in a personalized manner in vitro fertilization (IVF) cycles. In this review, we will present data from studies that have been conducted in the search for such biomarkers in order to identify proteins related to good sperm, oocyte, and embryo quality, as well as optimal endometrial receptivity, which may later lead to greater results and the desirable ART outcome.

Semen Proteomics of COVID-19 Convalescent Men Reveals Disruption of Key Biological Pathways Relevant to Male Reproductive Function

A considerable section of males suffered from COVID-19, with many experiencing long-term repercussions. Recovered males have been documented to have compromised fertility, albeit the mechanisms remain unclear. We investigated the impact of COVID-19 on semen proteome following complete clinical recovery using mass spectrometry. A label-free quantitative proteomics study involved 10 healthy fertile subjects and 17 COVID-19-recovered men. With 1% false discovery rate and >1 unique peptide stringency, MaxQuant analysis found 1099 proteins and 8503 peptides. Of the 48 differentially expressed proteins between the healthy and COVID-19-recovered groups, 21 proteins were downregulated and 27 were upregulated in COVID-19-recovered males. The major pathways involved in reproductive functions, such as sperm-oocyte recognition, testosterone response, cell motility regulation, adhesion regulation, extracellular matrix adhesion, and endopeptidase activity, were downregulated in COVID-19-recovered patients according to bioinformatics analysis. Furthermore, the targeted approach revealed significant downregulation of semenogelin 1 and prosaposin, two proteins related to male fertility. Therefore, we demonstrate the alteration of semen proteome in response to COVID-19, thus disrupting the male reproductive function despite the patient's clinical remission. Hence, to understand fertility-related biological processes triggered by this infection, a protracted evaluation of the consequences of COVID-19 in recovered men is warranted.

SERPINA5 Protein in Cumulus-Oocyte Complexes Increases the Fertilisation Ability of Mouse Sperm

Obtaining high-quality sperm is key to improving the success rate of assisted reproductive technology (ART). Although cytokines secreted by cumulus-oocyte complexes (COCs) bind to sperm surface receptors to improve sperm quality, the effects of adding mouse COCs to human tubal fluid (HTF) medium on sperm capacitation have not yet been explored. Eight-week-old ICR mouse COCs were added to HTF medium and crushed to obtain the post-modified HTF medium. Compared with using HTF medium, the fertilisation rate and number of sperm combined with the zona pellucida significantly increased after in vitro capacitation using the post-modified HTF medium (P < 0.01). Proteomic and Western blotting analyses showed that the level of SERPINA5 in sperm increased significantly following in vitro capacitation with the post-modified HTF medium (P < 0.05). Immunohistochemical staining analysis demonstrated that SERPINA5 protein was expressed in mouse cumulus cells. A SERPINA5 antibody was added in the post-modified HTF medium to block the effects of SERPINA5 after in vitro capacitation, which significantly decreased the fertilisation rate and the number of sperm combined with the zona pellucida (P < 0.05). Recombinant mouse SERPINA5 protein (1 ~ 2 μg/ml) was added to HTF medium and the fertilisation rate and the number of sperm combined with the zona pellucida significantly increased (P < 0.01). Moreover, recombinant human SERPINA5 protein (5 μg/ml) was added before human semen freezing. Compared with adding no SERPINA5 protein, the percentage of normal sperm morphology and the intact acrosome significantly increased (P < 0.05). Our study provides a reference method for optimising sperm quality in the process of in vitro capacitation.

Differential apoptotic gene expression in the male partners of infertile couples with normal and abnormal sperm parameters

OBJECTIVE

The purpose of this study was to investigate the cellular and molecular levels of apoptosis induction in three groups of male partners of infertile couples, one featuring subjects with normal sperm parameters and unexplained male infertility (UMI), one including men with abnormal sperm parameters, and one with fertile men as controls.

METHODS

Twenty-five infertile men with abnormal sperm parameters and 25 men with UMI and normal sperm parameters were recruited as experimental group I and experimental group II; 25 fertile men were included as controls. The mRNA levels of Fas, Fas ligand, Caspase 8, Bax, and Bcl2 were measured in the three groups. The cellular rates of early and late apoptosis were assessed using annexin V and propidium iodide staining.

RESULTS

The expression of Bax, Bcl2, and the Bax/Bcl2 ratio in experimental group I was significantly higher than that in experimental group II and controls. However, the Bax/Bcl2 ratio was less than 1 among all groups. No significant difference was found among study groups regarding the gene expression of Fas, Fas ligand, and Caspase 8. No significant difference was seen in early apoptotic rates of sperm among study groups. The highest number of necrotic sperm cells was detected in experimental group I.

CONCLUSIONS

The findings showed that the external pathways of apoptosis were not activated in the absence of external stimuli of sperm apoptosis in ejaculated sperm. Regardless of fertility status, apoptosis gene induction in the internal pathway was associated with abnormalities in sperm motility and/or morphology in men with abnormal parameters.

Simulating nature in sperm selection for assisted reproduction

Sperm selection in the female reproductive tract (FRT) is sophisticated. Only about 1,000 sperm out of millions in an ejaculate reach the fallopian tube and thus have a chance of fertilizing an oocyte. In assisted reproduction techniques, sperm are usually selected using their density or motility, characteristics that do not reflect their fertilization competence and, therefore, might result in failure to fertilize the oocyte. Although sperm processing in in vitro fertilization (IVF) and intrauterine insemination (IUI) bypasses many of the selection processes in the FRT, selection by the cumulus mass and the zona pellucida remain intact. By contrast, the direct injection of a sperm into an oocyte in intracytoplasmic sperm injection (ICSI) bypasses all natural selection barriers and, therefore, increases the risk of transferring paternal defects such as fragmented DNA and genomic abnormalities in sperm to the resulting child. Research into surrogate markers of fertilization potential and into simulating the natural sperm selection processes has progressed. However, methods of sperm isolation - such as hyaluronic acid-based selection and microfluidic isolation based on sperm tactic responses - use only one or two parameters and are not comparable with the multistep sperm selection processes naturally occurring within the FRT. Fertilization-competent sperm require a panel of molecules, including zona pellucida-binding proteins and ion channel proteins, that enable them to progress through the FRT to achieve fertilization. The optimal artificial sperm selection method will, therefore, probably need to use a multiparameter tool that incorporates the molecular signature of sperm with high fertilization potential, and their responses to external cues, within a microfluidic system that can replicate the physiological processes of the FRT in vitro.

A comparison of different O-antigen serogroups of Escherichia coli in semen samples of fertile and infertile men

Objective

Male genital tract infections have been associated with infertility, and Escherichia coli has drawn increasing attention as an important bacterium in this context. This investigation aimed to characterize and compare the distributions of O-antigen serogroups of E. coli in the semen samples of fertile and infertile men.

Methods

In this case-control study, semen samples were collected from 618 fertile and 1,535 infertile men. The E. coli-positive samples were evaluated in terms of concentration, morphology, viability, and motility parameters according to the World Health Organization 2010 guidelines. Finally, different serogroups of E. coli were identified by multiplex polymerase chain reaction targeting the O-antigen variations of the bacterium.

Results

The prevalence of E. coli among fertile men was significantly higher than among infertile men (p<0.001). The sperm morphology, viability, and motility in the E. coli-positive fertile group were significantly higher than in the E. coli-positive infertile group (p<0.001). E. coli O6 was the most prevalent serogroup found in both groups. However, there was no significant difference in the frequency of different serogroups of E. coil between the two groups (p=0.55).

Conclusion

Despite the higher prevalence of E. coli among fertile men, E. coli had more detrimental effects on semen parameters in infertile men. There was no significant difference in E. coli serogroups between the fertile and infertile groups.

Proteomics study reveals the molecular mechanisms underlying cryotolerance induced by mild sublethal stress in human sperm

The preconditioning of human sperm with sublethal nitrosative stress before cryopreservation can potentially improve the thawed sperm quality. However, the underlying mechanisms behind this protective strategy are not entirely understood. We compared the cryosurvival of human sperm exposed to 0.01 μM nitric oxide (NO) throughout the cryopreservation and used multiplexed quantitative proteomics approach to identify changes in the proteome profile of preconditioned sperm cells. Semen samples were obtained from 30 normospermia donors and then each sample was divided into three equal parts: fresh (F), frozen-control (C), and frozen exposed to nitric oxide (NO). The sperm undergoing mild sublethal stress showed higher values for motility and viability compared to the frozen control sperm. Moreover, out of 2912 identified proteins, 248 proteins were detected as differentially abundant proteins (DAPs) between cryopreserved groups and fresh group (F) (p < 0.05). Gene ontology (GO) analysis of differentially abundant proteins indicated that the abundance of proteins associated with glycolysis, gluconeogenesis, and fertilization processes was reduced while oxidative phosphorylation pathway was increased in abundance in cryopreserved sperm compared to the fresh sperm. Moreover, redox protein such as thioredoxin 17 was increased in abundance in the NO group compared to the control freezing group. Therefore, the pre-conditioning of sperm prior to cryopreservation may play an important role in maintaining the redox balance in mitochondria of sperm after freezing. Overall, our results indicate that arylsulfatase A (ARSA), serine protease 37 (PRSS37), and sperm surface protein (SP17) may potentially serve as protein biomarkers associated with screening the fertilization potential of the thawed sperm.

Unraveling Subcellular and Ultrastructural Changes During Vitrification of Human Spermatozoa: Effect of a Mitochondria-Targeted Antioxidant and a Permeable Cryoprotectant

Mitochondria-targeted antioxidants have great potential to counterbalance the generated reactive oxygen species (ROS) because they cross the inner membrane of the mitochondria. Still, their use was not reported in vitrified human spermatozoa. Our laboratory has successfully vitrified spermatozoa without the use of permeable cryoprotectants, but subcellular-level evidence was missing. Therefore, this study aimed to improve spermatozoa vitrification using a mitochondria-targeted antioxidant (mitoquinone, MitoQ), reveal ultrastructural changes in the spermatozoa due to the use of a permeable cryoprotectant, and report alterations of functional proteins during the spermatozoa vitrification process. For this, each of 20 swim-up-prepared ejaculates was divided into seven aliquots and diluted with a vitrification medium supplemented with varying concentrations of MitoQ (0.02 and 0.2 μM), glycerol (1, 4, and 6%), and a combination of MitoQ and glycerol. All aliquots were vitrified by the aseptic capillary method developed in our laboratory. The spermatozoa function assays revealed that the addition of either MitoQ (0.02 μM), glycerol (1%), or a combination of MitoQ (0.02 μM) and glycerol (1%) in the vitrification medium results in better or equivalent spermatozoa quality relative to the control. Transmission electron microscopy revealed that MitoQ protects the spermatozoa from undergoing ultrastructural alterations, but glycerol induced ultrastructural alterations during the vitrification process. Next, we performed label-free quantitative proteomics and identified 1,759 proteins, of which 69, 60, 90, and 81 were altered in the basal medium, 0.02 μM MitoQ, 1% glycerol, and Mito-glycerol groups, respectively. Actin, tubulins, and outer dense fiber proteins were not affected during the vitrification process. Some of the identified ubiquitinating enzymes were affected during spermatozoa vitrification. Only a few proteins responsible for phosphorylation were altered during vitrification. Similarly, several proteins involved in spermatozoa–egg fusion and fertilization (IZUMO1 and Tektin) were not affected during the vitrification process. In conclusion, MitoQ attenuates the vitrification-induced ultrastructural changes and alterations in the key proteins involved in spermatozoa functions and fertilization.

Seminal exosomes - An important biological marker for various disorders and syndrome in human reproduction

BACKGROUND

Exosomes are nano-sized membrane vesicles, secreted by different types of cells into the body's biological fluids. They are found in abundance in semen as compared to other fluids. Exosomes contain a cargo of lipid molecules, proteins, phospholipids, cholesterol, mRNAs, and miRNAs. Each molecule of seminal exosomes (SE) has a potential role in male reproduction for childbirth. Many potential candidates are available within the seminal exosomes that can be used as diagnostic markers for various diseases or syndromes associated with male reproduction. Also these seminal exospmes play a major role in female reproductive tract for effective fertilization.

AIM

The aim of this review is to focus on the advancement of human seminal exosomal research and its various properties.

METHODS

We used many databases like Scopus, Google scholar, NCBI-NLM and other sources to filter the articles of interest published in exosomes. We used phrases like "Exosomes in human semen", "Composition of exosomes in human semen" and other relevant words to filter the best articles.

RESULTS

Seminal exosomes play a major role in sperm functions like cell-to-cell communication, motility of the sperm cells, maintaining survival capacity for the sperm in the female reproductive tract and spermatogenesis. Also, seminal exosomes are used as a carrier for many regulatory elements using small RNA molecules. miRNAs of the seminal exosomes can be used as a diagnostic marker for prostate cancer instead of prostate specific antigen (PSA). Epididymosomes can be used as a biomarker for reproductive diseases and male infertility.

CONCLUSION

Seminal exosomes could be used as biological markers for various reproductive disorders, male infertility diagnosis, and it can be used in anti-retroviral research for the identification of novel therapeutics for HIV-1 infection and transmission.

Membrane lipid replacement with nano-micelles in human sperm cryopreservation improves post-thaw function and acrosome protein integrity

RESEARCH QUESTION

Membrane lipid replacement (MLR) of oxidized membrane lipids can restore sperm cellular membrane functionality and help improve surface protein stability during cryopreservation. What are the effects of MLR with nano-micelles made from a glycerophospholipid (GPL) mixture and cholesterol-loaded cyclodextrin (CLC), on the cryosurvival and expression of acrosome-related proteins in thawed human spermatozoa?

DESIGN

Twenty samples were used to determine the optimum level of nano-micelles by incubation of semen with different concentrations of GPL (0.1 and 1%) and CLC (1 and 2 mg/ml) (including GPL-0.1, GPL-1, CLC-1, CLC-2, CLC-1/GPL-0.1, CLC-2/GPL-0.1, CLC-1/GPL-1 and CLC-2/GPL-1) before cryopreservation. Then, 30 semen samples were collected, and each sample was divided into the following three aliquots: fresh, frozen control and frozen incubated with optimum level of nano-micelles (0.1% GPL and 1 mg/ml CLC).

RESULTS

CLC-1/GPL-0.1 and GPL-0.1 significantly increased motility parameters. CLC-1, GPL-0.1 and CLC-1/GPL-0.1 significantly improved viability rate compared with frozen control group. Significantly higher mitochondrial activity and acrosome integrity, and a lower rate of apoptosis, were observed in the CLC-1/GPL-0.1 compared with the frozen control group. The expression ratios of arylsulfatase A (ARSA), serine protease 37 (PRSS37), serine protease inhibitor Kazal-type 2 (SPINK2) and equatorin (EQTN) significantly increased compared with the frozen control group.

CONCLUSIONS

Modification of membrane cholesterol and GPL mixtures in spermatozoa enhances their acrosome protein integrity by inhibiting early apoptotic changes and spontaneous acrosome reactions.

Mitochondrial Functionality in Male Fertility: From Spermatogenesis to Fertilization

Mitochondria are structurally and functionally distinct organelles that produce adenosine triphosphate (ATP) through oxidative phosphorylation (OXPHOS), to provide energy to spermatozoa. They can also produce reactive oxidation species (ROS). While a moderate concentration of ROS is critical for tyrosine phosphorylation in cholesterol efflux, sperm–egg interaction, and fertilization, excessive ROS generation is associated with male infertility. Moreover, mitochondria participate in diverse processes ranging from spermatogenesis to fertilization to regulate male fertility. This review aimed to summarize the roles of mitochondria in male fertility depending on the sperm developmental stage (from male reproductive tract to female reproductive tract). Moreover, mitochondria are also involved in testosterone production, regulation of proton secretion into the lumen to maintain an acidic condition in the epididymis, and sperm DNA condensation during epididymal maturation. We also established the new signaling pathway using previous proteomic data associated with male fertility, to understand the overall role of mitochondria in male fertility. The pathway revealed that male infertility is associated with a loss of mitochondrial proteins in spermatozoa, which induces low sperm motility, reduces OXPHOS activity, and results in male infertility.

Recent advances and controversies in diagnosing and treating male infertility

Interest in male infertility has increased, as it plays an important role in up to 50% of couples struggling with infertility, which is an estimated 48.5 million couples globally. Despite recent advances, diagnosing and treating male infertility remain a significant clinical challenge owing to complex multifactorial pathways and the diversity of treatment options. This review will assess current controversial topics on male infertility such as the use of home-based semen testing, management of subclinical varicocele, and recent advances in the field of sperm proteomics.

Fertility Relevance Probability Analysis Shortlists Genetic Markers for Male Fertility Impairment

Impairment of male fertility is one of the major public health issues worldwide. Nevertheless, genetic causes of male sub- and infertility can often only be suspected due to the lack of reliable and easy-to-use routine tests. Yet, the development of a marker panel is complicated by the large quantity of potentially predictive markers. Actually, hundreds or even thousands of genes could have fertility relevance. Thus, a systematic method enabling a selection of the most predictive markers out of the many candidates is required. As a criterion for marker selection, we derived a gene-specific score, which we refer to as fertility relevance probability (FRP). For this purpose, we first categorized 2,753 testis-expressed genes as either candidate markers or non-candidates, according to phenotypes in male knockout mice. In a parallel approach, 2,502 genes were classified as candidate markers or non-candidates based on phenotypes in men. Subsequently, we conducted logistic regression analyses with evolutionary rates of genes (dN/dS), transcription levels in testis relative to other organs, and connectivity of the encoded proteins in a protein-protein interaction network as covariates. In confirmation of the procedure, FRP values showed the expected pattern, thus being overall higher in genes with known relevance for fertility than in their counterparts without corresponding evidence. In addition, higher FRP values corresponded with an increased dysregulation of protein abundance in spermatozoa of 37 men with normal and 38 men with impaired fertility. Present analyses resulted in a ranking of genes according to their probable predictive power as candidate markers for male fertility impairment. Thus, AKAP4, TNP1, DAZL, BRDT, DMRT1, SPO11, ZPBP, HORMAD1, and SMC1B are prime candidates toward a marker panel for male fertility impairment. Additional candidate markers are DDX4, SHCBP1L, CCDC155, ODF1, DMRTB1, ASZ1, BOLL, FKBP6, SLC25A31, PRSS21, and RNF17. FRP inference additionally provides clues for potential new markers, thereunder TEX37 and POU4F2. The results of our logistic regression analyses are freely available at the PreFer Genes website (https://prefer-genes.uni-mainz.de/).

Protein profiling in unlocking the basis of varicocele-associated infertility

Varicocele is one of the major causes of male infertility and has a negative impact on spermatogenesis. The conventional semen analysis does not reveal the underlying subcellular mechanisms associated with defects in spermatozoa. Proteomics and bioinformatics analysis can be used to identify the molecular aetiologies associated with poor semen quality in varicocele patients. Mitochondrial dysfunction has been identified as the main factor affecting normal physiological functions of spermatozoa. This article discusses the proteomic studies of spermatozoa and seminal plasma in varicocele patients. Proteomics can identify potential spermatozoa and seminal plasma biomarkers in varicocele-mediated male infertility. In future, these protein biomarkers can be useful in the development of noninvasive diagnostic and therapeutic strategies for varicocele patients.

Male Infertility is a Women's Health Issue-Research and Clinical Evaluation of Male Infertility Is Needed

Infertility is a devastating experience for both partners as they try to conceive. Historically, when a couple could not conceive, the woman has carried the stigma of infertility; however, men and women are just as likely to contribute to the couple’s infertility. With the development of assisted reproductive technology (ART), the treatment burden for male and unexplained infertility has fallen mainly on women. Equalizing this burden requires reviving research on male infertility to both improve treatment options and enable natural conception. Despite many scientific efforts, infertility in men due to sperm dysfunction is mainly diagnosed by a semen analysis. The semen analysis is limited as it only examines general sperm properties such as concentration, motility, and morphology. A diagnosis of male infertility rarely includes an assessment of internal sperm components such as DNA, which is well documented to have an impact on infertility, or other components such as RNA and centrioles, which are beginning to be adopted. Assessment of these components is not typically included in current diagnostic testing because available treatments are limited. Recent research has expanded our understanding of sperm biology and suggests that these components may also contribute to the failure to achieve pregnancy. Understanding the sperm’s internal components, and how they contribute to male infertility, would provide avenues for new therapies that are based on treating men directly for male infertility, which may enable less invasive treatments and even natural conception.

PITHD1 is a proteasome-interacting protein essential for male fertilization

The proteasome is a protein-degrading molecular complex that is necessary for protein homeostasis and various biological functions, including cell cycle regulation, signal transduction, and immune response. Proteasome activity is finely regulated by a variety of proteasome-interacting molecules. PITHD1 is a recently described molecule that has a domain putatively capable of interacting with the proteasome. However, it is unknown whether PITHD1 can actually bind to proteasomes and what it does in vivo Here we report that PITHD1 is detected specifically in the spermatids in the testis and the cortical thymic epithelium in the thymus. Interestingly, PITHD1 associates with immunoproteasomes in the testis, but not with thymoproteasomes in the thymus. Mice deficient in PITHD1 exhibit severe male infertility accompanied with morphological abnormalities and impaired motility of spermatozoa. Furthermore, PITHD1 deficiency reduces proteasome activity in the testis and alters the amount of proteins that are important for fertilization capability by the sperm. However, the PITHD1-deficient mice demonstrate no detectable defects in the thymus, including T cell development. Collectively, our results identify PITHD1 as a proteasome-interacting protein that plays a nonredundant role in the male reproductive system.

Effect of Antioxidant Supplementation on the Sperm Proteome of Idiopathic Infertile Men

Antioxidant supplementation in idiopathic male infertility has a beneficial effect on semen parameters. However, the molecular mechanism behind this effect has not been reported. The objective of this study was to evaluate the sperm proteome of idiopathic infertile men pre- and post-antioxidant supplementation. Idiopathic infertile men were provided with oral antioxidant supplementation once daily for a period of 6 months. Of the 379 differentially expressed proteins (DEPs) between pre- and post-antioxidant treatment patients, the majority of the proteins (n = 274) were overexpressed following antioxidant treatment. Bioinformatic analysis revealed the activation of oxidative phosphorylation pathway and upregulation of key proteins involved in spermatogenesis, sperm maturation, binding of sperm, fertilization and normal reproductive function. In addition, the transcriptional factors associated with antioxidant defense system (PPARGC1A) and free radical scavenging (NFE2L2) were predicted to be functionally activated post-treatment. Key DEPs, namely, NDUFS1, CCT3, PRKARA1 and SPA17 validated by Western blot showed significant overexpression post-treatment. Our novel proteomic findings suggest that antioxidant supplementation in idiopathic infertile men improves sperm function at the molecular level by modulating proteins involved in CREM signaling, mitochondrial function and protein oxidation. Further, activation of TRiC complex helped in nuclear compaction, maintenance of telomere length, flagella function, and expression of zona pellucida receptors for sperm-oocyte interaction.