CRISP2, CATSPER1 and PATE1 Expression in Human Asthenozoospermic Semen

MicroRNAs in spermatogenesis dysfunction and male infertility: clinical phenotypes, mechanisms and potential diagnostic biomarkers

Infertility affects approximately 10-15% of couples worldwide who are attempting to conceive, with male infertility accounting for 50% of infertility cases. Male infertility is related to various factors such as hormone imbalance, urogenital diseases, environmental factors, and genetic factors. Owing to its relationship with genetic factors, male infertility cannot be diagnosed through routine examination in most cases, and is clinically called 'idiopathic male infertility.' Recent studies have provided evidence that microRNAs (miRNAs) are expressed in a cell-or stage-specific manner during spermatogenesis. This review focuses on the role of miRNAs in male infertility and spermatogenesis. Data were collected from published studies that investigated the effects of miRNAs on spermatogenesis, sperm quality and quantity, fertilization, embryo development, and assisted reproductive technology (ART) outcomes. Based on the findings of these studies, we summarize the targets of miRNAs and the resulting functional effects that occur due to changes in miRNA expression at various stages of spermatogenesis, including undifferentiated and differentiating spermatogonia, spermatocytes, spermatids, and Sertoli cells (SCs). In addition, we discuss potential markers for diagnosing male infertility and predicting the varicocele grade, surgical outcomes, ART outcomes, and sperm retrieval rates in patients with non-obstructive azoospermia (NOA).

The Role of Circular RNAs in Male Infertility and Reproductive Cancers: A Narrative Review

Infertility is a global health problem affecting about 15% of all couples, of which 50% are due to male infertility. Although the etiology of infertility is known in most infertile men, idiopathic male infertility remains a challenge. Therefore, there is a need for novel diagnostic methods to detect the underlying mechanisms and develop appropriate therapies. Recent studies have focused on the role of non-coding RNAs (ncRNAs) in male infertility. Circular RNAs (CircRNAs), a type of ncRNAs, are found to play a key role in the development of some pathological conditions, including cardiovascular diseases, diabetes, cancers, autoimmune diseases, etc. Several studies have reported the presence of CircRNAs and their target genes in the human reproductive system. In addition, their expression in testicular tissues, sperm cells, and seminal fluid has been identified. Abnormal expression of CircRNAs has been associated with azoospermia and asthenozoospermia in infertile men. The present narrative review provides a brief description of the role of CircRNAs in spermatogenic cells, male infertility, and reproductive cancers. In addition, some CircRNAs have been identified as potential biomarkers for disease detection and treatment.

Circular RNAs and Their Role in Male Infertility: A Systematic Review

Male infertility is a global health problem that is on the rise. Today, many noncoding RNAs (ncRNAs) are associated with male infertility. Circular RNAs (circRNAs) have recently drawn attention, but a comprehensive understanding of the role of circRNAs in male infertility is limited. This systematic review investigates the differential expression of circRNAs in male infertility or circRNAs that could serve as candidate biomarkers. The PRISMA guidelines were used to search PubMed and Web of Science on 11 January 2023. Inclusion criteria were human participants, experimental studies aiming to associate circRNAs with male infertility reporting differentially expressed circRNAs, and the English language. A total of 156 articles were found, and after the screening and eligibility stages, 13 studies were included in the final sample. Many circRNAs are deregulated in male infertility, and their interactions with miRNAs play an important role in affecting cellular processes and pathways. CircRNAs could also be used as biomarkers to screen patients before sperm retrieval. However, most studies focus on the role of circRNAs in azoospermia, and there is a knowledge gap regarding other subtypes of male infertility. Future research is needed to explore the exact mechanism of action of circRNAs and investigate their use as biomarkers.

Sperm Motility Annotated Genes: Are They Associated with Impaired Fecundity?

Sperm motility is a prerequisite for achieving pregnancy, and alterations in sperm motility, along with sperm count and morphology, are commonly observed in subfertile men. The aim of the study was to determine whether the expression level of genes annotated with the Gene Ontology (GO) term 'sperm motility' differed in sperm collected from healthy men and men diagnosed with oligoasthenozoospermia. Reverse transcription quantitative real-time PCR (RT-qPCR), quantitative mass spectrometry (LC-MS/MS), and enrichment analyses were used to validate a set of 132 genes in 198 men present at an infertility clinic. Out of the 132 studied sperm-motility-associated genes, 114 showed differentially expressed levels in oligoasthenozoospermic men compared to those of normozoospermic controls using an RT-qPCR analysis. Of these, 94 genes showed a significantly lower expression level, and 20 genes showed a significantly higher expression level. An MS analysis of sperm from an independent cohort of healthy and subfertile men identified 692 differentially expressed proteins, of which 512 were significantly lower and 180 were significantly higher in oligoasthenozoospermic men compared to those of the normozoospermic controls. Of the 58 gene products quantified with both techniques, 48 (82.75%) showed concordant regulation. Besides the sperm-motility-associated proteins, the unbiased proteomics approach uncovered several novel proteins whose expression levels were specifically altered in abnormal sperm samples. Among these deregulated proteins, there was a clear overrepresentation of annotation terms related to sperm integrity, the cytoskeleton, and energy-related metabolism, as well as human phenotypes related to spermatogenesis and sperm-related abnormalities. These findings suggest that many of these proteins may serve as diagnostic markers of male infertility. Our study reveals an extended number of sperm-motility-associated genes with altered expression levels in the sperm of men with oligoasthenozoospermia. These genes and/or proteins can be used in the future for better assessments of male factor infertility.

Quantitative proteomics of sperm tail in asthenozoospermic patients: exploring the molecular pathways affecting sperm motility

Asthenozoospermia, characterized by low sperm motility, is one of the most common causes of male infertility. While many intrinsic and extrinsic factors are involved in the etiology of asthenozoospermia, the molecular basis of this condition remains unclear. Since sperm motility results from a complex flagellar structure, an in-depth proteomic analysis of the sperm tail can uncover mechanisms underlying asthenozoospermia. This study quantified the proteomic profile of 40 asthenozoospermic sperm tails and 40 controls using TMT-LC-MS/MS. Overall, 2140 proteins were identified and quantified where 156 proteins have not been described earlier in sperm tail. There were 409 differentially expressed proteins (250 upregulated and 159 downregulated) in asthenozoospermia which by far is the highest number reported earlier. Further, bioinformatics analysis revealed several biological processes, including mitochondrial-related energy production, oxidative phosphorylation (OXPHOS), citric acid cycle (CAC), cytoskeleton, stress response, and protein metabolism altered in asthenozoospermic sperm tail samples. Collectively, our findings reveal the importance of mitochondrial energy production and induced stress response as potential mechanisms involved in the loss of sperm motility in asthenozoospermia.

Identification of New Candidate Genes Related to Semen Traits in Duroc Pigs through Weighted Single-Step GWAS

Semen traits play a key role in the pig industry because boar semen is widely used in purebred and crossbred pigs. The production of high-quality semen is crucial to ensuring a good result in artificial insemination. With the wide application of artificial insemination in the pig industry, more and more attention has been paid to the improvement of semen traits by genetic selection. The purpose of this study was to identify the genetic regions and candidate genes associated with semen traits of Duroc boars. We used weighted single-step GWAS to identify candidate genes associated with sperm motility, sperm progressive motility, sperm abnormality rate and total sperm count in Duroc pigs. In Duroc pigs, the three most important windows for sperm motility-sperm progressive motility, sperm abnormality rate, and total sperm count-explained 12.45%, 9.77%, 15.80%, and 12.15% of the genetic variance, respectively. Some genes that are reported to be associated with spermatogenesis, testicular function and male fertility in mammals have been detected previously. The candidate genes CATSPER1, STRA8, ZSWIM7, TEKT3, UBB, PTBP2, EIF2B2, MLH3, and CCDC70 were associated with semen traits in Duroc pigs. We found a common candidate gene, STRA8, in sperm motility and sperm progressive motility, and common candidate genes ZSWIM7, TEKT3 and UBB in sperm motility and sperm abnormality rate, which confirms the hypothesis of gene pleiotropy. Gene network enrichment analysis showed that STRA8, UBB and CATSPER1 were enriched in the common biological process and participated in male meiosis and spermatogenesis. The SNPs of candidate genes can be given more weight in genome selection to improve the ability of genome prediction. This study provides further insight into the understanding the genetic structure of semen traits in Duroc boars.

Cytochalasin D restores nuclear size acting on F-actin and IZUMO1 localization in low-quality spermatozoa

In spermatozoa, the nuclear F-actin supports the acroplaxome, a subacrosomal structure involved in the correct exposure of several acrosomal membrane proteins; among them, the glycoprotein IZUMO1 is the major protein involved in sperm-oocyte fusion. Nuclear F-actin is also involved in sperm head shaping and chromosome compartmentalization. To date, few notions regarding the bivalent role of F-actin on sperm chromatin organization and IZUMO1 positioning have been reported. In our work, we characterized subcellular organization of F-actin in human high- and low-quality spermatozoa (A- and B-SPZ), respectively, showing that F-actin over-expression in sperm head of B-SPZ affected IZUMO1 localization. A correct IZUMO1 repositioning following in vitro induction of F-actin depolymerization, by cytochalasin D treatment, occurred. Interestingly, F-actin depolymerization was also associated with a correct acrosome repositioning, thus to favor a proper acrosome reaction onset, with changes in sperm nuclear size parameters and histone acetylation rate reaching high-quality conditions. In conclusion, the current work shows a key role of F-actin in the control of IZUMO1 localization as well as chromatin remodeling and acetylation events.

The circRERE/miR-144-3p/TLR2/MMP9 signaling axis in COPD pulmonary monocytes promotes the EMT of pulmonary epithelial cells

Chronic obstructive pulmonary disease (COPD) is a serious threat to human health, but an effective targeted therapy for COPD is still lacking at present. During the progression of COPD, the epithelial mesenchymal transition (EMT) ensures the remodeling of pulmonary epithelial cells, and it could not be precisely targeted due to its complex and elusive mechanism. In this study, we determined that the TLR2/MMP9 axis is upregulated in the pulmonary monocytes in cigarette smoke (CS)-induced COPD mice. Using a co-culture system, we identified that the TLR2/MMP9 axis in pulmonary monocytes promotes the EMT of pulmonary epithelial cells. Further, our results confirmed that miR-144-3p inhibits TLR2 expression in monocytes by directly binding to the 3'UTR of TLR2. Finally, we proved that circRERE works as a sponge to antagonize miR-144-3p and promote TLR2 expression in monocytes. Thus, our results conclude that the circRERE/miR-144-3p/TLR2/MMP9 axis in COPD pulmonary monocytes is critical for CS-induced COPD and circRERE may serve as a potential target for COPD.

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.