Advanced Paternal Age in Focus: Unraveling Its Influence on Assisted Reproductive Technology Outcomes

As global demographics shift toward increasing paternal age, the realm of assisted reproductive technologies (ARTs), particularly in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI), faces new challenges and opportunities. This study provides a comprehensive exploration of the implications of advanced paternal age on ART outcomes. Background research highlights the social, cultural, and economic factors driving men toward later fatherhood, with a focus on the impact of delayed paternity on reproductive outcomes. Methods involve a thorough review of existing literature, centering on changes in testicular function, semen quality, and genetic and epigenetic shifts associated with advancing age. Study results point to intricate associations between the father's age and ART outcomes, with older age being linked to diminished semen quality, potential genetic risks, and varied impacts on embryo quality, implantation rates, and birth outcomes. The conclusions drawn from the current study suggest that while advanced paternal age presents certain risks and challenges, understanding and mitigating these through strategies such as sperm cryopreservation, lifestyle modifications, and preimplantation genetic testing can optimize ART outcomes. Future research directions are identified to further comprehend the epigenetic mechanisms and long-term effects of the older father on offspring health. This study underscores the need for a comprehensive approach in navigating the intricacies of delayed fatherhood within the context of ART, aiming for the best possible outcomes for couples and their children.

Multiple genes in the Pate5-13 genomic region contribute to ADAM3 processing†

Sperm proteins undergo post-translational modifications during sperm transit through the epididymis to acquire fertilizing ability. We previously reported that the genomic region coding Pate family genes is key to the proteolytic processing of the sperm membrane protein ADAM3 and male fertility. This region contains nine Pate family genes (Pate5-13), and two protein-coding genes (Gm27235 and Gm5916), with a domain structure similar to Pate family genes. Therefore, in this study, we aimed to identify key factors by narrowing the genomic region. We generated three knockout (KO) mouse lines using CRISPR/Cas9: single KO mice of Pate10 expressed in the caput epididymis; deletion KO mice of six caput epididymis-enriched genes (Pate5-7, 13, Gm27235, and Gm5916) (Pate7-Gm5916 KO); and deletion KO mice of four genes expressed in the placenta and epididymis (Pate8, 9, 11, and 12) (Pate8-12 KO). We observed that the fertility of only Pate7-Gm5916 KO males was reduced, whereas the rest remained unaffected. Furthermore, when the caput epididymis-enriched genes, Pate8 and Pate10 remained in Pate7-Gm5916 KO mice were independently deleted, both KO males displayed more severe subfertility due to a decrease in mature ADAM3 and a defect in sperm migration to the oviduct. Thus, our data showed that multiple caput epididymis-enriched genes within the region coding Pate5-13 cooperatively function to ensure male fertility in mice.

Unravelling the epigenetic impact: Oxidative stress and its role in male infertility-associated sperm dysfunction

Male infertility is a multifactorial condition influenced by epigenetic regulation, oxidative stress, and mitochondrial dysfunction. Oxidative stress-induced damage leads to epigenetic modifications, disrupting gene expression crucial for spermatogenesis and fertilization. Paternal exposure to oxidative stress induces transgenerational epigenetic alterations, potentially impacting male fertility in offspring. Mitochondrial dysfunction impairs sperm function, while leukocytospermia exacerbates oxidative stress-related sperm dysfunction. Therefore, this review focuses on understanding these mechanisms as vital for developing preventive strategies, including targeting oxidative stress-induced epigenetic changes and implementing lifestyle modifications to prevent male infertility. This study investigates how oxidative stress affects the epigenome and sperm production, function, and fertilization. Unravelling the molecular pathways provides valuable insights that can advance our scientific understanding. Additionally, these findings have clinical implications and can help to address the significant global health issue of male infertility.

Differential Proteomic Analysis of Human Sperm: A Systematic Review to Identify Candidate Targets to Monitor Sperm Quality

PURPOSE

The advent of proteomics provides new opportunities to investigate the molecular mechanisms underlying male infertility. The selection of relevant targets based on a single analysis is not always feasible, due to the growing number of proteomic studies with conflicting results. Thus, this study aimed to systematically review investigations comparing the sperm proteome of normozoospermic and infertile men to define a panel of proteins with the potential to be used to evaluate sperm quality.

MATERIALS AND METHODS

A literature search was conducted on PubMed, Web of Science, and Scopus databases following the PRISMA guidelines. To identify proteins systematically reported, first the studies were divided by condition into four groups (asthenozoospermia, low motility, unexplained infertility, and infertility related to risk factors) and then, all studies were analysed simultaneously (poor sperm quality). To gain molecular insights regarding identified proteins, additional searches were performed within the Human Protein Atlas, Mouse Genome Informatics, UniProt, and PubMed databases.

RESULTS

Thirty-two studies were included and divided into 4 sub-analysis groups. A total of 2752 proteins were collected, of which 38, 1, 3 and 2 were indicated as potential markers for asthenozoospermia, low motility, unexplained infertility and infertility related to risk factors, respectively, and 58 for poor sperm quality. Among the identified proteins, ACR, ACRBP, ACRV1, ACTL9, AKAP4, ATG3, CCT2, CFAP276, CFAP52, FAM209A, GGH, HPRT1, LYZL4, PRDX6, PRSS37, REEP6, ROPN1B, SPACA3, SOD1, SPEM1, SPESP1, SPINK2, TEKT5, and ZPBP were highlighted due to their roles in male reproductive tissues, association with infertility phenotypes or participation in specific biological functions in spermatozoa.

CONCLUSIONS

Sperm proteomics allows the identification of protein markers with the potential to overcome limitations in male infertility diagnosis and to understand changes in sperm function at the molecular level. This study provides a reliable list of systematically reported proteins that could be potential targets for further basic and clinical studies.

Qiangjing tablets ameliorate asthenozoospermia via mitochondrial ubiquitination and mitophagy mediated by LKB1/AMPK/ULK1 signaling

CONTEXT

Therapeutic effects of Qiangjing tablets (QJT) on sperm vitality and asthenozoospermia (AZS) have been confirmed. However, the mechanism of action remains unclear.

OBJECTIVE

This study investigates the effects of QJT on AZS and the underlying mechanism of action.

MATERIALS AND METHODS

Sixty Sprague-Dawley rats were randomly divided into six groups: Control, ORN (ornidazole; 200 mg/kg), ORN + QJT-low (0.17 g/mL), ORN + QJT-middle (0.33 g/mL), ORN + QJT-high (0.67 g/mL), and ORN + QJT + Radicicol (0.67 g/mL QJT and 20 mg/kg radicicol) groups. Pathological evaluation and analysis of mitophagy were conducted by H&E staining and transmission electron microscopy, respectively. Reactive oxygen species were detected by flow cytometry. Protein expression was determined by Western blotting.

RESULTS

QJT significantly improved ORN-treated sperm motility and kinematic parameters, as well as the pathological symptoms of testicular and epididymal tissues. In particular, QJT mitigated impaired mitochondrial morphology, and increased the PHB, Beclin-1, LC3-II protein, and ROS levels (p < 0.05), and reduced the protein expression levels of LC3-I and p62 (p < 0.05). Mechanistically, QJT antagonized the downregulation of SCF and Parkin protein levels (p < 0.05). Furthermore, QJT significantly increased the protein expressions levels of LKB1, AMPKα, p-AMPKα, ULK1 and p-ULK1 (p < 0.05). The ameliorative effect of QJT on pathological manifestations, mitochondrial morphology, and the expressions of mitophagy and mitochondrial ubiquitination-related proteins was counteracted by radicicol.

DISCUSSION AND CONCLUSIONS

QJT improved AZS via mitochondrial ubiquitination and mitophagy mediated by the LKB1/AMPK/ULK1 signaling pathway. Our study provides a theoretical basis for the treatment of AZS and male infertility.

Male reproductive ageing: a radical road to ruin

In modern post-transition societies, we are reproducing later and living longer. While the impact of age on female reproductive function has been well studied, much less is known about the intersection of age and male reproduction. Our current understanding is that advancing age brings forth a progressive decline in male fertility accompanied by a reduction in circulating testosterone levels and the appearance of age-dependent reproductive pathologies including benign prostatic hypertrophy and erectile dysfunction. Paternal ageing is also associated with a profound increase in sperm DNA damage, the appearance of multiple epigenetic changes in the germ line and an elevated mutational load in the offspring. The net result of such changes is an increase in the disease burden carried by the progeny of ageing males, including dominant genetic diseases such as Apert syndrome and achondroplasia, as well as neuropsychiatric conditions including autism and spontaneous schizophrenia. The genetic basis of these age-related effects appears to involve two fundamental mechanisms. The first is a positive selection mechanism whereby stem cells containing mutations in a mitogen-activated protein kinase pathway gain a selective advantage over their non-mutant counterparts and exhibit significant clonal expansion with the passage of time. The second is dependent on an age-dependent increase in oxidative stress which impairs the steroidogenic capacity of the Leydig cells, disrupts the ability of Sertoli cells to support the normal differentiation of germ cells, and disrupts the functional and genetic integrity of spermatozoa. Given the central importance of oxidative stress in defining the impact of chronological age on male reproduction, there may be a role for antioxidants in the clinical management of this process. While animal studies are supportive of this strategy, carefully designed clinical trials are now needed if we are to realize the therapeutic potential of this approach in a clinical context.

The Activated AMPK/mTORC2 Signaling Pathway Associated with Oxidative Stress in Seminal Plasma Contributes to Idiopathic Asthenozoospermia

Asthenozoospermia is a common form of abnormal sperm quality in idiopathic male infertility. While most sperm-mediated causes have been investigated in detail, the significance of seminal plasma has been neglected. Herein, we aimed to investigate the possible pathogenic factors leading to decreased sperm motility based on seminal plasma. Semen was collected from normo- (NOR, n = 70), idiopathic oligo- (OLI, n = 57), and idiopathic asthenozoospermic (AST, n = 53) patients. Using attenuated total reflection-Fourier transform infrared coupled with chemometrics, distinct differences in the biochemical compositions of nucleic acids, protein structure (amides I, II, and III), lipids, and carbohydrates in seminal plasma of AST were observed when compared to NOR and OLI. Compared with NOR and OLI, the levels of peptide aggregation, protein phosphorylation, unsaturated fatty acid, and lipid to protein ratio were significantly increased in AST; however, the level of lipid saturation was significantly decreased in seminal plasma of AST. Compared with NOR, the levels of ROS, MDA, 8-iso-prostaglandin F2α (8-isoPGF2α), and the ratio of phospho-AMPKα/AMPKα1 were significantly increased in AST; however, the levels of SOD, glutathione S-transferase (GSTs), protein carbonyl derivative (PC), and the ratio of phospho-Rictor/Rictor were significantly decreased in seminal plasma of AST. Changes of the AMPK/mTORC2 signaling in the seminal microenvironment possibly induce abnormal glucose and lipid metabolism, which impairs energy production. Oxidative stress potentially damages seminal plasma lipids and proteins, which in turn leads to impaired sperm structure and function. These findings provide evidence that the changes in seminal plasma compositions, oxidative stress, and activation of the AMPK/mTORC2 signaling contribute to the development of asthenozoospermia.

Shenjing Guben Wan promotes sperm development by increasing the activity of seminiferous epithelium Sertoli cells

Background

Infertility is an important social problem. Asthenozoospermia (AZS) is a common pathological cause of male infertility, but its pathogenesis is unclear. Shenjing Guben Wan (SJGBW), a traditional Chinese medicine, has shown remarkable effects during the clinical treatment of oligozoospermia or AZS.

Methods

In this study, clinical evaluations were carried out on 184 AZS patients receiving SJGBW treatment, including sperm count, sperm quality, and pregnancy rate. Also, ornidazole was used to build an AZS mouse model, and SJGBW treatment was administered. The sperm quantity and fertility of mice in different groups were evaluated; a cholecystokinin octapeptide-8 (CCK-8) experiment was carried out to test the activity of seminiferous epithelium Sertoli cells, and immunohistochemistry and the Terminal Deoxynucleotidyl Transferase-mediated dUTP Nick-End Labeling (TUNEL) method were employed to test the pathological information and expression of the Sertoli cell surface marker in the testicular tissues of mice in each group.

Results

The sperm vitality, progressive sperm motility, and sperm morphology of patients who received SJGBW treatment were all improved (P<0.05). In the AZS group, the average sperm count, sperm vitality, pregnancy rate, and female mouse litters were all lower relative to mice in the control group. Following SJGBW treatment, the average sperm count, sperm vitality, pregnancy rate, and female mouse litters of mice in the AZS group were all significantly improved. The cytobiological experimental results showed that compared with the serum of normal male mice in the control group, the drug serum containing SJGBW could improve the cell vitality and proliferative ability of seminiferous epithelium Sertoli cells in AZS mice. Furthermore, the TUNEL results showed that the seminiferous tubule Sertoli cells and mesenchymal cells of the AZS mice exhibited the most significant apoptosis, which was alleviated following SJGBW treatment. Moreover, the levels of Sertoli cell marker, SOX9, and anti-apoptosis protein, Bcl2, in SJGBW-treated mice were both higher than that in AZS mice.

Conclusions

SJGBW can promote the development and maturation of germ cells by facilitating the proliferation of Sertoli cells in AZS patients, thereby improving the fertility of these patients.

Expressions of HSPA1L and HSPA9 are associated with poor sperm quality of low-motility spermatozoa in fertile men

Human semen is a heterogeneous group containing a portion of low-motility sperm, which may determine the sperm quality evaluation. Abnormally expressed proteins in low-motility spermatozoa will be the candidates for sperm biology research. By comparing proteomes of high- or low-motility spermatozoa from the same semen of normal fertile men, 21 differentially expressed proteins were identified. Proteins with molecular chaperone function were significantly over-represented, of which HSPA1L and HSPA9 significantly decreased in low-motility sperm. Compared with young adult testes with normal spermatogenesis, HSPA1L and HSPA9 had decreased expressions in elderly testis characterised with poor spermatogenesis, suggesting their associations with spermatogenesis. Decreased expressions of HSPA1L and HSPA9 in low-motility spermatozoa were validated by Western Blot and immunofluorescence quantification analysis. HSPA1L was mainly expressed on sperm post-acrosome and midpiece, whilst HSAP9 was mainly expressed on acrosome and sperm tail. HSPA1L antibody could inhibit sperm motility validated by antibody blocking experiment, whilst HSPA9 antibody showed no significant effect on sperm motility. The study demonstrated that low-motility spermatozoa from fertile men had poor sperm quality, in which differential expressed proteins were promising markers for evaluating sperm quality, understanding mechanism of male infertility with unexplained causes, and providing new idea for male infertility research.

Qiangjing Tablets Regulate Apoptosis and Oxidative Stress via Keap/Nrf2 Pathway to Improve the Reproductive Function in Asthenospermia Rats

Asthenozoospermia (AZS), is a common cause of male infertility. Currently, most drugs for azoospermia lack desirable therapeutic efficiency, therefore developing new drug therapy is important. Qiangjing tablets could enhance renal function and improve sperm quality. The purpose of this study was to examine whether Qiangjing tablets could improve the reproductive function in azoospermia rats through activating the Nrf2/ARE pathway, and how to regulate energy metabolism and oxidative stress in this process. Sperm motility, sperm concentration and sperm viability were detected by WLJY-9000 Weili Digital Color Sperm Quality Detection System. HE staining was used to observe the pathological condition of testis in AZS rats. Cell apoptosis was analyzed by Tunnel staining and flow cytometry. The changes of mitochondrial membrane potential were detected by JC-1. The levels of Estradiol, testosterone and luteinizing hormone, activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), and content of malondialdehyde (MDA) and glutathione (GSH) were detected by ELISA. The effects of Qiangjing Tablets on GC-1 spgs and Nrf2 protein were investigated through CCK-8 assay and western blot. The expression levels of HO-1, Keap1, and P-Nrf2 were detected by western blot. The results demonstrated that Qiangjing tablets upregulated levels of sperm motility, sperm concentration and sperm viability, which was shown to significantly increase levels of HO-1, Keap1, P-Nrf2, Estradiol and testosterone, along with increasing the activity of SOD, GSH-Px and GSH and suppressing the MDA content, luteinizing hormone and Vimentin level. Qiangjing tablets could significantly inhibit spermatogenic cells apoptosis and promote GC-1 spgs viability, increase PE/FITC ratio, mitochondrial membrane potential and reduc oxidative stress. Qiangjing tablets protected spermatogenic cell to upregulate male sex hormoneto, improved the sperm quality and reproductive function in AZS rats via activating the Keap/Nrf2 signaling pathway.

iTRAQ-based proteomics of testicular interstitial fluid during aging in mice

Advancing age is associated with a decline in fertility and testicular function in males. The testicular interstitial fluid (TIF) bathing the seminiferous tubules and testicular interstitium is considered an important part of the testicular microenvironment. However, the TIF proteome in mice and whether it changes with age remain unclear. This study aimed to map the TIF proteome and identify differentially abundant proteins (DEPs) among young, middle-aged, and old mice using isobaric tags for relative and absolute quantification (iTRAQ) coupled with liquid chromatography-tandem mass spectrometry. A total of 1477 proteins were identified in murine TIF. The abundance of 706 proteins showed a linear change trend with age, of which 360 and 346 proteins increased and decreased, respectively. In addition, 45 age-related DEPs were identified (P < 0.05, with at least 1.2-fold up- or downregulation). Bioinformatic analyses revealed that these proteins were involved in "actin cytoskeleton organization," "intrinsic apoptotic signaling pathway," and "regulation of protein transport." Comparative analysis with relevant proteomes previously reported further revealed the characteristics of mouse TIF proteome. Moreover, two of the age-related DEPs (Fga and Qsox1) were also found to be age-related differentially expressed proteins in human blood plasma and senescence-related secretome of human peritubular myoid cells. Taken together, these findings may represent the foundation for a better understanding of the molecular function of TIF and testicular aging.

CRISP2, CATSPER1 and PATE1 Expression in Human Asthenozoospermic Semen

The etiology of human asthenozoospermia is multifactorial. The need to unveil molecular mechanisms underlying this state of infertility is, thus, impelling. Circular RNAs (circRNAs) are involved in microRNA (miRNA) inhibition by a sponge activity to protect mRNA targets. All together they form the competitive endogenous RNA network (ceRNET). Recently, we have identified differentially expressed circRNAs (DE-circRNAs) in normozoospermic and asthenozoospermic patients, associated with high-quality (A-spermatozoa) and low-quality (B-spermatozoa) sperm. Here, we carried out a differential analysis of CRISP2, CATSPER1 and PATE1 mRNA expression in good quality (A-spermatozoa) and low quality (B-spermatozoa) sperm fractions collected from both normozoospermic volunteers and asthenozoospermic patients. These sperm fractions are usually separated on the basis of morphology and motility parameters by a density gradient centrifugation. B-spermatozoa showed low levels of mRNAs. Thus, we identified the possible ceRNET responsible for regulating their expression by focusing on circTRIM2, circEPS15 and circRERE. With the idea that motility perturbations could be rooted in quantitative changes of transcripts in sperm, we evaluated circRNA and mRNA modulation in A-spermatozoa and B-spermatozoa after an oral amino acid supplementation known to improve sperm motility. The profiles of CRISP2, CATSPER1 and PATE1 proteins in the same fractions of sperm well matched with the transcript levels. Our data may strengthen the role of circRNAs in asthenozoospermia and shed light on the molecular pathways linked to sperm motility regulation.

Upregulated microRNA-423-5p promotes oxidative stress through targeting glutathione S-transferase mu 1 in asthenozoospermia

The dysregulation of microRNAs (miRNAs) plays an important role in asthenozoospermia. This study evaluated the sperm microRNA-423-5p (miR-423-5p) expression in asthenozoospermia and normozoospermia, exploring the role of miR-423-5p in asthenozoospermia. Eighty participants were divided into asthenozoospermic (AZS, n = 40) and normozoospermic (Norm, n = 40) groups. Fresh semen samples were collected and the sperm cells were separated. Quantitative Real-Time polymerase chain reaction was used to measure the sperm miR-423-5p level. Receiver operating characteristic curve (ROC) was employed to test the diagnostic performance of miR-423-5p in asthenospermia. Dual-reporter luciferase assay was adopted to confirm the target gene of miR-423-5p. The target gene level in asthenozoospermia and normozoospermia was measured, and the biological function of target gene in asthenozoospermia was evaluated. Results showed that the miR-423-5p expression level in the AZS group was higher than that in Norm group, which was positively correlated with the severity of asthenozoospermia. ROC analysis of miR-423-5p showed an area under curve (AUC) of 0.69 (95% confidence interval = 0.57-0.80, p <0 .01), with 80% sensitivity and 60% specificity. Glutathione S-transferase mu 1 (GSTM1) is a target gene of miR-423-5p, which significantly decreased in the AZS group. Compared with Norm group, glutathione S-transferase (GST) activity and total antioxidant capacity (TAC) level decreased, while malondialdehyde (MDA) level increased in the AZS group. Furthermore, GST activity and TAC level were negatively correlated with miR-423-5p expression, while MDA level was positively correlated with miR-423-5p expression. In conclusion, the sperm miR-423-5p level significantly was upregulated in asthenozoospermia. High-level miR-423-5p inhibited sperm motility through targeting GSTM1 to promote oxidative stress.

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.

Effect of senescence on morphological, functional and oxidative features of fresh and cryopreserved canine sperm

The present research aimed to compare the hormonal profile, sperm quality and freezability of young and senile dogs. Dogs were assigned into Young Group (n = 11) and Senile Group (n = 11), additionally divided into Fresh Semen Group and Cryopreserved Semen Group. Males were evaluated for libido score and blood estrogen and testosterone assay. Sperm morphofunctional evaluations were performed based on Computer Assisted Sperm Analysis, morphology, mitochondrial activity, mitochondrial membrane potential, plasma and acrosomal membrane integrity, and DNA fragmentation. Sperm oxidative features were: protein oxidation, lipid peroxidation and production of advanced glycation end-products. Young dogs had higher libido score, sperm velocity average pathway, linearity of motility and mitochondrial activity index and lower percentage of major defects, total defects and proximal cytoplasmic droplet, despite the lack of difference between hormone profile of aged dogs. Fresh semen of senile dogs had increased percentage of spermatozoa with high mitochondrial membrane potential compared to young dogs and to cryopreserved sperm. Cryopreserved semen of young dogs had higher acrosomal membrane integrity compared to the Senile Group. In conclusion, sperm of aged dogs have reduced quality, signaled by higher morphological defects, ultimately altering sperm mitochondrial function and sperm kinetics. Furthermore, spermatozoa from senile dogs are more sensible to cryoinjury.

Yishentongluo decoction in treatment of idiopathic asthenozoospermia infertility: Study protocol for a randomized controlled trial

BACKGROUND

The reproductive dilemma faced by men has always been the focus of the whole society. Idiopathic asthenozoospermia (AZS), as one of the common causes of male infertility, lack of specific treatment. Traditional Chinese medicine has shown potential benefits in the management of male infertility. Yishentongluo decoction (YSTL) is a representative Chinese herbal formula; however, there is still no rigorous clinical trial supporting its application. Therefore, we designed a randomized controlled trial to evaluate the efficacy and safety of YSTL for patients with idiopathic AZS and explain the possible action mechanisms of YSTL in improving sperm motility.

METHODS

In this randomized controlled study, a total of 160 eligible patients will be assigned to YSTL group or the Levocarnitine oral solution group in a 1:1 ratio. The treatment period will be 12 weeks and the follow-up period will last 4 weeks. The primary outcome will be the the progressive (motility), sperm rate (%). Secondary outcomes will include the progressive (motility) + non-progressive (motility) sperm rate(%), total effective sperm count, inner mitochondrial membrane potential (MMP) in spermatozoa, and spouse pregnancy rate (%). Safety outcomes will cover electrocardiogram , blood tests (including blood routine test, hepatic function, and renal function), urine routine test, and stool routine test. The semen parameters, sperm MMP test, and all the safety outcomes will be performed at the baseline, 4th, 8th and 12th week. The pregnancy outcome will be evaluated at 4 weeks after treatment.

DISCUSSION

This study will provide initial evidence regarding the efficacy and safety of YSTL in the treatment of idiopathic AZS with kidney deficiency and blood stasis pattern. In addition, potential mechanisms of YSTL in improving sperm motility will be explored based on sperm MMP test.

TRIAL REGISTRATION

Chinese Clinical Trials Register identifier, ChiCTR2000033290, registered on 26 May 2020.

Molecular Changes Induced by Oxidative Stress that Impair Human Sperm Motility

A state of oxidative stress (OS) and the presence of reactive oxygen species (ROS) in the male reproductive tract are strongly correlated with infertility. While physiological levels of ROS are necessary for normal sperm functioning, elevated ROS production can overwhelm the cell's limited antioxidant defenses leading to dysfunction and loss of fertilizing potential. Among the deleterious pleiotropic impacts arising from OS, sperm motility appears to be particularly vulnerable. Here, we present a mechanistic account for how OS contributes to altered sperm motility profiles. In our model, it is suggested that the abundant polyunsaturated fatty acids (PUFAs) residing in the sperm membrane serve to sensitize the male germ cell to ROS attack by virtue of their ability to act as substrates for lipid peroxidation (LPO) cascades. Upon initiation, LPO leads to dramatic remodeling of the composition and biophysical properties of sperm membranes and, in the case of the mitochondria, this manifests in a dissipation of membrane potential, electron leakage, increased ROS production and reduced capacity for energy production. This situation is exacerbated by the production of cytotoxic LPO byproducts such as 4-hydroxynonenal, which dysregulate molecules associated with sperm bioenergetic pathways as well as the structural and signaling components of the motility apparatus. The impact of ROS also extends to lesions in the paternal genome, as is commonly seen in the defective spermatozoa of asthenozoospermic males. Concluding, the presence of OS in the male reproductive tract is strongly and positively correlated with reduced sperm motility and fertilizing potential, thus providing a rational target for the development of new therapeutic interventions.

EIF4G1 is a novel candidate gene associated with severe asthenozoospermia

BACKGROUND

Asthenozoospermia (AZS), also known as asthenospermia, is characterized by reduced motility of ejaculated spermatozoa and is detected in more than 40% of infertile patients. Because the proportion of progressive spermatozoa in severe AZS is <1%, severe AZS is an urgent challenge in reproductive medicine. Several genes have been reported to be relevant to severe asthenospermia. However, these gene mutations are found only in sporadic cases and can explain only a small fraction of severe AZS, so additional genetic pathogenies need to be explored.

METHODS AND RESULTS

By screening the variant genes in a patient with severe AZS using whole exome sequencing, we identified biallelic mutations c.2521C>T: p.(Pro841Ser) (NC_000003.11: g.184043412C>T) in exon13 and c.2957C>G: p.(Ala986Gly) (NC_000003.11: g.184045117C>G) in exon17 in the eukaryotic translation initiation factor 4 gamma 1 gene (EIF4G1, RefSeq: NM_004953.4, OMIM: 600495) of the patient. Both of the mutation sites are rare and potentially deleterious. Transmission electron microscopy analysis showed a disrupted axonemal structure with mitochondrial sheath defects. The EIF4G1 protein level was extremely low, and the mitochondrial marker cytochrome c oxidase subunit 4I1 (COXIV, OMIM: 123864) and mitochondrially encoded ATP synthase 6 (ATP6, OMIM: 516060) protein levels were also decreased in the patient's spermatozoa as revealed by WB and IF analysis. This infertility associated with this condition was overcome by intracytoplasmic sperm injections, as his wife became pregnant successfully.

CONCLUSION

Our experimental findings indicate that the EIF4G1 gene is a novel candidate gene that may be relevant to severe AZS.

mTOR Signaling Pathway Regulates Sperm Quality in Older Men

Understanding how age affects fertility becomes increasingly relevant as couples delay childbearing toward later stages of their lives. While the influence of maternal age on fertility is well established, the impact of paternal age is poorly characterized. Thus, this study aimed to understand the molecular mechanisms responsible for age-dependent decline in spermatozoa quality. To attain it, we evaluated the impact of male age on the activity of signaling proteins in two distinct spermatozoa populations: total spermatozoa fraction and highly motile/viable fraction. In older men, we observed an inhibition of the mechanistic target of rapamycin complex 1 (mTORC1) in the highly viable spermatozoa population. On the contrary, when considering the entire spermatozoa population (including defective/immotile/apoptotic cells) our findings support an active mTORC1 signaling pathway in older men. Additionally, total spermatozoa fractions of older men presented increased levels of apoptotic/stress markers [e.g., cellular tumor antigen p53 (TP53)] and mitogen-activated protein kinases (MAPKs) activity. Moreover, we established that the levels of most signaling proteins analyzed were consistently and significantly altered in men older than 27 years of age. This study was the first to associate the mTOR signaling pathway with the age impact on spermatozoa quality. Additionally, we constructed a network of the sperm proteins associated with male aging, identifying TP53 as a central player in spermatozoa aging.

Integrated Analyses of Phenotype and Quantitative Proteome of CMTM4 Deficient Mice Reveal Its Association with Male Fertility

The chemokine-like factor (CKLF)-like MARVEL transmembrane domain-containing family (CMTM) is a gene family that has been implicated in male reproduction. CMTM4 is an evolutionarily conserved member that is highly expressed in the testis. However, its function in male fertility remains unknown. Here, we demonstrate that CMTM4 is associated with spermatogenesis and sperm quality. Using Western blotting and immunohistochemical analyses, we found CMTM4 expression to be decreased in poor-quality human spermatozoa, old human testes, and testicular biopsies with nonobstructive azoospermia. Using CRISPR-Cas9 technology, we knocked out the Cmtm4 gene in mice. These Cmtm4 knockout (KO) mice showed reduced testicular daily sperm production, lower epididymal sperm motility and increased proportion of abnormally backward-curved sperm heads and bent sperm midpieces. These mice also had an evident sub-fertile phenotype, characterized by low pregnancy rates on prolonged breeding with wild type female mice, reduced in vitro fertilization efficiency and a reduced percentage of acrosome reactions. We then performed quantitative proteomic analysis of the testes, where we identified 139 proteins to be downregulated in Cmtm4-KO mice, 100 (71.9%) of which were related to sperm motility and acrosome reaction. The same proteomic analysis was performed on sperm, where we identified 3588 proteins with 409 being differentially regulated in Cmtm4-KO mice. Our enrichment analysis showed that upregulated proteins were enriched with nucleosomal DNA binding functions and the downregulated proteins were enriched with actin binding functions. These findings elucidate the roles of CMTM4 in male fertility and demonstrates its potential as a promising molecular candidate for sperm quality assessment and the diagnosis or treatment of male infertility.

Nine genes abundantly expressed in the epididymis are not essential for male fecundity in mice

Background

Spermatozoa become competent for fertilization during transit through the epididymis. As spermatozoa from the proximal caudal epididymis can fertilize eggs, proteins from the caput and corpus epididymis are required for sperm maturation.

Objectives

Microarray analysis identified that more than 17,000 genes are expressed in the epididymis; however, few of these genes demonstrate expression restricted to the epididymis. To analyze epididymis‐enriched gene function in vivo, we generated knockout (KO) mutations in nine genes that are abundantly expressed in the caput and corpus region of the epididymis.

Materials and methods

KO mice were generated using the CRISPR/Cas9 system. The histology of the epididymis was observed with hematoxylin and eosin staining. KO males were caged with wild‐type females for 3–6 months to check fertility.

Results

We generated individual mutant mouse lines having indel mutations in Pate1, Pate2, or Pate3. We also deleted the coding regions of Clpsl2, Epp13, and Rnase13, independently. Finally, the 150 kb region encoding Gm1110, Glb1l2, and Glb1l3 was deleted to generate a triple KO mouse line. Histology of the epididymis and sperm morphology of all KO lines were comparable to control males. The females mated with these KO males delivered pups at comparable numbers as control males.

Discussion and conclusion

We revealed that nine genes abundantly expressed in the caput and corpus epididymis are dispensable for sperm function and male fecundity. CRISPR/Cas9‐mediated KO mice generation accelerates the screening of epididymis‐enriched genes for potential functions in reproduction.

Aberrant expression of sperm‑specific glycolytic enzymes are associated with poor sperm quality

The energy required for normal sperm function is mainly generated by glycolysis and oxidative phosphorylation. Testis‑specific glycolytic enzymes are expressed in germ cells and present in mature spermatozoa. The objective of the present study was to investigate the association between aberrant expression of glycolytic enzymes and human sperm quality. In silico analysis of glyceraldehyde‑3‑phosphate dehydrogenase, testis‑specific (GAPDHS), phosphoglycerate kinase 2 (PGK2) and lactate dehydrogenase (LDHC) identified that they were exclusively expressed in post‑meiotic germ cells and this was validated in human testes using immunohistochemistry. Compared with the testes of young adults, markedly lower expression levels of these glycolytic enzymes were observed in the testes of elderly adults. Similarly, low levels were observed in immature and asthenozoospermic spermatozoa. The expression levels of GAPDHS, PGK2 and LDHC in the spermatozoa were closely correlated with progressive sperm motility. The results indicated that the expression of GAPDHS, PGK2 and LDHC in sperm may be associated with sperm quality, and there may be a similar molecular mechanism underlying sperm quality in immature and asthenozoospermic spermatozoa. This study reveals a close association of glycolytic enzymes with sperm quality. The data may greatly contribute to the molecular evaluation of sperm quality and the diagnosis and treatment of asthenozoospermia.

Proteomic analyses reveal lower expression of TEX40 and ATP6V0A2 proteins related to calcium ion entry and acrosomal acidification in asthenozoospermic males

AIMS

Idiopathic nature of male infertility disorder needs to be investigated by different horizons of molecular biology for its treatment and to device male contraceptive. Further, it can also aid in advancement of assisted reproductive technology (ART), as nowadays the failure and disquiets of ART are consistent. Herein, we have attempted to find out proteins responsible for male infertility by comparing proteome profile of sperms collected from normal control and asthenozoospermic (AS) males.

MAIN METHODS

Differential proteome profiles were studied by 2-dimensional differential gel electrophoresis (2D-DIGE) and mass spectrometry. The confirmation of proteome profiling results was done by western blotting and ELISA. Quantitative reverse-transcription-PCR was also performed in an independent cohort of AS and normal individuals to investigate the transcriptional regulation of proteins.

KEY FINDINGS

Although seven differentially regulated proteins were identified, highpoints of the study were two proteins, TEX40 and ATP6V0A2. Lower expression of a crucial sperm motility related protein, TEX40 is reported for the first time in clinically diagnosed AS males in the present investigation. Most likely with reference to previous findings the down regulation of TEX40 leads to fewer entries of calcium ions in the sperm and lower expression of ATP6V0A2 is responsible for acrosomal de-acidification.

SIGNIFICANCE

Conclusively, the down regulation of these two proteins in AS males might result in diminished sperm motility. The findings can be worthwhile for male contraception and ART management besides their use for male infertility therapy.

Decreased expression of heat shock protein A4L in spermatozoa is positively related to poor human sperm quality

Heat shock protein A4L (HSPA4L), which is highly expressed in the testis, is correlated with male fertility. However, the relationship between HSPA4L expression and sperm quality remains unknown. In the present study, a systematic characterization of HSPA4L expression on spermatozoa was performed. HSPA4L is highly expressed in the human testis, characterized by abundant localization in testicular spermatocytes and round spermatids. Compared with the testis from young adults (aged 27-36 years old), downregulated expression of HSPA4L in the testis from elderly adults (aged 78-82 years old) was observed. Immunofluorescence quantification demonstrated the localization of HSPA4L in the middle piece of sperm. Compared with mature spermatozoa, a similar lower intensity and localization percentage of HSPA4L in immature and asthenozoospermic spermatozoa were observed, and the consistently decreased expression of HSPA4L in immature and asthenozoospermic spermatozoa was validated by western blot analysis. Functional analysis revealed a correlation between HSPA4L and sperm motility by Spearman correlation analysis and its involvement in sperm-oocyte penetration by the human sperm-hamster egg penetration test. The current study demonstrates that HSPA4L is a promising marker for the assessment of sperm quality and provides clues for exploring biomarkers for the molecular diagnosis and treatment of male infertility.

An in silico analysis of human sperm genes associated with asthenozoospermia and its implication in male infertility

Asthenozoospermia is the most common clinical symptom of male infertility. Molecular markers associated with asthenozoospermia spermatozoa are scarcely identified. The objective of this study was to screen the differentially expressed genes (DEGs) in asthenozoospermia spermatozoa and assess the underlying bioinformatics roles in regulation of sperm quality.Based on gene expression omnibus (GEO) database, the GSE22331, GSE1133, and GSE4193 expression profile data were downloaded. The DEGs of asthenozoospermia spermatozoa were identified. Germ cell specific genes in DEGs were further screened. Then, gene ontology (GO) and over-representation analysis of DEGs were performed, followed by protein-protein interaction (PPI) network analysis. Expressions of selected genes of TEX11, ADAMTS5, ASRGL1, GMCL1, PGK2, KLHL10 in normozoospermia and asthenozoospermia spermatozoa were identified using real time Reverse Transcription-Polymerase Chain Reaction (RT-PCR).A total of 1323 DEGs were identified, including 1140 down-regulated genes. Twenty one and 96 down-regulated genes were especially expressed in spermatogonia and round spermatids, suggesting their testicular origins and influences on sperm quality. Bioinformatics analysis showed enriched functions of ubiquitin-like protein transferase or protein binding activities in down-regulated genes. Expressions of selected genes were validated by RT-PCR, which was consistent with bioinformatical results.The present study provided a novel insight into the understanding of sperm quality, and a potential method and dataset for the diagnosis and assessment of sperm quality in the event of male infertility.

Association of GRP78 promoter polymorphisms and serum GRP78 level with risk of asthenozoospermia

PURPOSE

The aim of this study was undertaken to investigate the association of 78-kDa glucose-regulated protein (GRP78) gene promoter polymorphisms with risk of asthenozoospermia (AZS) men. In addition, we performed association analysis between GRP78 promoter mutations and serum GRP78 level in asthenozoospermia.

METHODS

The study population comprised 400 subjects with AZS patients and 400 healthy controls. We assessed GRP78 rs3216733, rs17840761, and rs17840762 polymorphisms by using Snapshot SNP genotyping assays; serum GRP78 level was measured by enzyme-linked immunosorbent assay (ELISA). Semen quality was assessed by computer-assisted semen analysis.

RESULTS

We found that rs3216733 was associated with increased risk of AZS (Gd vs. dd: adjusted OR = 1.42, 95% CI, 1.06-1.93, P = 0.020; Gd/GG vs. dd: adjusted OR = 1.43, 95% CI, 1.08-1.91, P = 0.013; G vs. d adjusted OR = 1.26, 95% CI, 1.03-1.56, P = 0.027). The haplotype analyses showed the frequency of G-C-C haplotype was significantly higher in AZS (P = 0.026). The percentage of progressive motility sperm was lower in the asthenozoospermic men with Gd and Gd/GG genotypes than dd genotype (P = 0.003). Moreover, the serum GRP78 levels were significantly lower in rs3216733 Gd/GG genotypes compared with the dd genotype (P < 0.001).

CONCLUSION

Our findings suggest that rs3216733 Gd/GG genotypes contribute to poor sperm motility, probably by decreasing the level of GRP78.

Disturbed testicular expression of the estrogen-metabolizing enzymes CYP1A1 and COMT in infertile men with primary spermatogenic failure: possible negative implications on Sertoli cells

Estradiol (E₂ ) is normally metabolized to hydroxyestradiols and methoxyestradiols by CYP1A1, CYP1B1 and COMT. However, an altered production of these metabolites by a disturbed expression of these enzymes is associated with reproductive and non-reproductive pathologies. In vitro studies suggest that increased hydroxyestradiols and methoxyestradiols intratesticular generation is related to male infertility, but no studies have explored whether infertile men have a disturbed testicular expression of the enzymes that generate these E₂ metabolites. The aim of this study was to assess CYP1A1, CYP1B1 and COMT testicular expression at mRNA and protein level in men with spermatogenic impairment. Seventeen men with primary spermatogenic failure (13 with Sertoli cell-only syndrome and four with maturation arrest) and nine controls with normal spermatogenesis were subjected to testicular biopsy. mRNA was quantified using real-time RT-PCR and protein expression was evaluated using western blot and immunohistochemistry followed by integrated optic density analysis. Besides, the effects of hydroxyestradiols and methoxyestradiols on testosterone-induced transcriptional activity were evaluated in TM4 cells using a luciferase reporter assay system. Our results show that patients with Sertoli cell-only syndrome had significantly elevated COMT expression at the mRNA level, higher COMT immunoreactivity in their seminiferous tubules and increased protein expression of the soluble COMT isoform (S-COMT), whereas patients with maturation arrest had significantly elevated CYP1A1 mRNA levels and higher CYP1A1 immunoreactivity in interstitial space. Finally, 2-hydroxyestradiol decreased testosterone-induced transcriptional activity in Sertoli cells in vitro. In conclusion, male infertility is related to disturbed testicular expression of the enzymes responsible for producing hydroxyestradiols and/or methoxyestradiols. If these changes are related with increased intratesticular hydroxyestradiols and methoxyestradiols concentrations, they could elicit an impaired Sertoli cell function. Our results suggest CYP1A1 and COMT as new potential targets in treating male infertility.

Homozygous DNAH1 frameshift mutation causes multiple morphological anomalies of the sperm flagella in Chinese

This study aimed to investigate the genetic pathogeny of multiple morphological anomalies of the flagella (MMAF), which is a genetically heterogeneous disorder leading to male infertility. Nine patients with severe asthenozoospermia caused by MMAF were recruited. Whole genome sequencing and Sanger sequencing were performed, and we found that four of the nine patients were affected by the same homozygous frameshift mutation c.11726_11727delCT (p.[Pro3909ArgfsTer33]) in exon 73 of dynein axonemal heavy chain 1 ( DNAH1 ) gene. The parents and the sibling of proband 1 were all identified as heterozygous carriers. This mutation was distinct from previously reported DNAH1 mutations associated with MMAF and only affected the East Asian group. Furthermore, the variant DNAH1 protein could not be detected in spermatozoa by Western blot or immunofluorescence staining although DNAH1 mRNA was expressed in the spermatozoa. Scanning electron microscopy and transmission electron microscopy analysis showed the anomalies in sperm flagella morphology and ultrastructure in patients carrying this genetic variant. In conclusion, our results add to knowledge of the genetic pathogeny of MMAF and further confirmed the effectiveness of genetic screening in the diagnosis of MMAF.

Association of polymorphisms in PATE1 gene with idiopathic asthenozoospermia in Sichuan, China

PURPOSE

Idiopathic Asthenozoospermia (AZS) is a common symptom of male infertility described as reduced forward motility or absence of sperm motility. The PATE1 is generally expressed in male genital tract and related to sperm development, maturation and fertilization. However, the single nucleotide polymorphisms (SNPs) of the PATE1 gene which contribute to AZS were still unknown. For this reason, the possible association between the single nucleotide polymorphisms of the PATE1 gene and idiopathic asthenozoospermia was investigated in this research.

METHODS

108 idiopathic asthenozoospermia were screened by karyotype analysis, detection of Y microdeletions and mutations in 5 other genes from 140 clinical AZS. The sequence analyses of the PATE1 gene were conducted in 108 idiopathic asthenozoospermia and 106 fertile men with normospermic parameters in Sichuan, China.

RESULTS

In this study, a total 108 patients without chromosomal abnormalities, Y microdeletions and selected genes mutation were confirmed. The 1423G (odds ratio [OR] 1.939, 95% confidence interval [CI] 1.320-2.848, P=0.001) was found to be increased significantly in idiopathic asthenozoospermic patients compared with their fertile counterparts. This mutation substitutes a highly conserved glutamic to arginine at the position of the 47th amino acid which was shown to be located on the flank of the pleated sheet domain in PATE1 protein by the 3D model given by the Protein Model Portal (PMP). Moreover, PolyPhen-2 analysis predicted that this variant was "probably damaging".

CONCLUSIONS

These results suggested that PATE1 variant (A1423G) was probably one of the high risk genetic factors for idiopathic asthenozoospermia among males in Sichuan, China.

Organization, evolution and functions of the human and mouse Ly6/uPAR family genes

Members of the lymphocyte antigen-6 (Ly6)/urokinase-type plasminogen activator receptor (uPAR) superfamily of proteins are cysteine-rich proteins characterized by a distinct disulfide bridge pattern that creates the three-finger Ly6/uPAR (LU) domain. Although the Ly6/uPAR family proteins share a common structure, their expression patterns and functions vary. To date, 35 human and 61 mouse Ly6/uPAR family members have been identified. Based on their subcellular localization, these proteins are further classified as GPI-anchored on the cell membrane, or secreted. The genes encoding Ly6/uPAR family proteins are conserved across different species and are clustered in syntenic regions on human chromosomes 8, 19, 6 and 11, and mouse Chromosomes 15, 7, 17, and 9, respectively. Here, we review the human and mouse Ly6/uPAR family gene and protein structure and genomic organization, expression, functions, and evolution, and introduce new names for novel family members.

Characteristics of testis-specific phosphoglycerate kinase 2 and its association with human sperm quality

STUDY QUESTION

Is there an association between the expression of phosphoglycerate kinase (PGK) 2 in spermatozoa and sperm quality in both elderly men and young asthenozoospermia patients?

SUMMARY ANSWER

Spermatozoa from elderly men and young asthenozoospermia patients show decreased expression of PGK2, which has a close positive relationship with sperm quality.

WHAT IS KNOWN ALREADY

PGK1 and PGK2 are involved in spermatogenesis and thought to be related to sperm motility. However, limited information is known about their temporal-spatial expression in human spermatogenesis and their relationship with sperm quality.

STUDY DESIGN, SIZE, DURATION

This was a case-control study including 30 healthy young males (aged 28-31 years), 30 elderly men (aged 68-70 years), and 30 asthenozoospermic patients (aged 25-40 years, progressive motility <32%) who donated semen samples. Furthermore, young testes samples were obtained from five fathers (27-33 years old) who had died in car accidents, while aged testes samples were obtained from five elderly fathers (78-82 years old) who were prostate cancer patients.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Semen samples from young adults, elderly men and asthenozoospermic patients were prepared, and their parameters were assessed by Computer-Aided Sperm Analysis (CASA). Sperm proteins were extracted for western blot analysis. Immunohistochemistry was used to characterize the cellular localization of PGK1 and PGK2 in testes samples. Sperm immunofluorescence quantification experiments identified the differential expression of PGK1 and PGK2 in sperm from young adults, elderly men and asthenozoospermic patients. Antibodies against PGK1 and PGK2 were used to test their influence on sperm motility and penetration into viscous media. A modified Kremer test using methyl cellulose was adopted to assess sperm function via penetration into viscous media.

MAIN RESULTS AND THE ROLE OF CHANCE

Cellular localization analysis showed that PGK1 was mainly expressed in spermatogonia whereas PGK2 was mainly expressed in round spermatids. Expression levels of both PGKs were significantly decreased in the testis with ageing (P < 0.05). Western blot and immunofluorescence quantification showed markedly lower expression of PGK2 (P < 0.05) in sperm from elderly men or asthenozoospermic patients compared sperm from with healthy young men. Sperm functional analysis validated the close relationship between expression of PGK2 and sperm motility (staining percentage, r = 0.60, P < 0.05; intensity, r = 0.59, P < 0.05). Use of an anti-PGK2 antibody on sperm significantly decreased their ability to penetrate into a cervical mucus substitute (P < 0.05).

LIMITATIONS, REASONS FOR CAUTION

Before any clinical applications using PGK2 to assess sperm quality can be developed, more cases should be used to evaluate this approach.

WIDER IMPLICATIONS OF THE FINDINGS

The study provides new insights into the role of PGKs in male reproduction. The results also indicate that PGK2 is a promising molecular candidate for the assessment of sperm quality and the screening of male contraceptive targets.

STUDY FUNDING/COMPETING INTERESTS

This work was supported by grants from the National Natural Science Foundation of China (no. 81300533, 81370013 and 81000277) and Shandong Provincial Natural Science Foundation, China (ZR2013HQ002). The authors declare no competing financial interests.