The Roles of MicroRNAs in Male Infertility

Mitigative Effects of l-Arginine and N-Acetyl Cysteine against Cisplatin-Induced Testicular Dysfunction and Toxicity through the Regulation of Antioxidant, Anti-inflammatory, and Antiapoptotic Markers: Role of miR-155 and miR-34c Expression

Testicular dysfunction is a common adverse effect of cisplatin (CIS) administration as a chemotherapeutic drug. The current study has outlined the role of micro-RNAs (miR-155 and 34c) in CIS-induced testicular dysfunction and evaluated the protective effect of N-acetyl cysteine (NAC) and/or l-arginine (LA). Seven groups of Albino rats were used for this study. The control (C) group received physiological saline; the CIS group was injected CIS (7 mg/kg IP, once) on day 21 of the experiment; the NAC group was administered NAC (150 mg/kg intragastric, for 28 days); and the LA group was injected LA (50 mg/kg IP, for 28 days). NAC+CIS, LA+CIS, and NAC+LA+CIS groups received the above regime. CIS significantly reduced serum testosterone, LH, and FSH concentrations with decline of testicular enzyme activities. CIS caused significant elevation in testicular oxidative-stress biomarkers, inflammation-associated cytokines, and apoptosis markers, along with overexpression of miR-155 and low miR-34c expression. Additionally, marked testicular degenerative changes were observed in the examined histological section; a significant decrease in the expression of PCNA with significant increase in expressions of F4/80 and BAX was confirmed. The administration of NAC or LA upregulated testicular functions and improved histopathological and immunohistochemical changes as well as miRNA expression compared with the CIS-administered group. Rats receiving both NAC and LA showed a more significant ameliorative effect compared with groups receiving NAC or LA alone. In conclusion, NAC or LA showed an ameliorative effect against CIS-induced testicular toxicity and dysfunction through the regulation of antioxidant, anti-inflammatory, and antiapoptotic markers and via modulating miR-155 and miR-34c expression.

Integrative bioinformatics analysis to identify ferroptosis-related genes in non-obstructive azoospermia

PURPOSE

The objective of this study was to discern ferroptosis-related genes (FRGs) linked to non-obstructive azoospermia and investigate the associated molecular mechanisms.

METHOD

A dataset related to azoospermia was retrieved from the Gene Expression Omnibus database, and FRGs were sourced from GeneCards. Ferroptosis-related differentially expressed genes (FRDEGs) were discerned. Subsequently, these genes underwent analyses encompassing Gene Ontology and Kyoto Encyclopedia of Genes and Genomes, as well as protein-protein interaction (PPI) networks and assessments of functional similarity. Following the identification of hub genes, an exploration of immune infiltration, single-cell expression, diagnostic utility, and interactions involving hub genes, RNA-binding proteins (RBPs), transcription factors (TFs), microRNAs (miRNAs), and drugs was conducted.

RESULTS

A total of 35 differentially expressed FRGs were discerned. These genes demonstrated enrichment in functions and pathways associated with ferroptosis. From the PPI network, eight hub genes were selected. Functional similarity analysis highlighted the potential pivotal roles of HMOX1 and GPX4 in azoospermia. Analysis of immune cell infiltration indicated a significant decrease in activated dendritic cells in the azoospermia group, with notable correlations between hub genes, particularly SAT1 and HMGCR, and immune cell infiltration. Unique expression patterns of hub genes across various cell types in the human testis were observed, with GPX4 prominently enriched in spermatid/sperm. Eight hub genes exhibited robust diagnostic value (AUC > 0.75). Lastly, a comprehensive hub gene-miRNA-TF-RBP-drug network was constructed.

CONCLUSION

In summary, our investigation unveiled eight FRDEGs associated with azoospermia, which hold potential as biomarkers for the diagnosis and treatment of azoospermia.

Mechanisms of Male Reproductive Sterility Triggered by Dysbiosis of Intestinal Microorganisms

The intestinal microbiota, comprised of bacteria, archaea, and phages, inhabits the gastrointestinal tract of the organism. Male reproductive sterility is currently a prominent topic in medical research. Increasing research suggests that gut microbiota dysbiosis can result in various reproductive health problems. This article specifically investigates the impact of gut microbiota dysbiosis on male reproductive infertility development. Gut microbiota imbalances can disrupt the immune system and immune cell metabolism, affecting testicular growth and sperm production. This dysfunction can compromise the levels of hormones produced and secreted by the endocrine glands, affecting male reproductive health. Furthermore, imbalance of the gut microbiota can disrupt the gut-brain-reproductive axis, resulting in male reproductive infertility. This article explores how the imbalance of the gut microbiota impacts male reproductive infertility through immune regulation, endocrine regulation, and interactions of the gut-brain-reproductive axis, concluding with recommendations for prevention and treatment.

MicroRNAs in Male Fertility

Around 50% of all occurrences of infertility are attributable to the male factor, which is a significant global public health concern. There are numerous circumstances that might interfere with spermatogenesis and cause the body to produce abnormal sperm. While evaluating sperm, the count, the speed at which they migrate, and their appearance are the three primary characteristics that are analyzed. MicroRNAs, also known as miRNAs, are present in all physiological fluids and tissues. They participate in both physiological and pathological processes. Researches have demonstrated that the expression of microRNA genes differs in infertile men. These genes regulate spermatogenesis at various stages and in several male reproductive cells. Hence, microRNAs have the potential to act as useful indicators in the diagnosis and treatment of male infertility and other diseases affecting male reproduction. Despite this, additional research is necessary to determine the precise miRNA regulation mechanisms.

Exploring the regulatory role of Linc00893 in asthenozoospermia: Insights into sperm motility and SSC viability

The role of long intergenic noncoding RNA 00893 (Linc00893) in asthenozoospermia (AS) and its impact on sperm motility remains unclear The present study explored the effect of Linc00893 on AS, specifically its effect on sperm motility and its relationship with spermatogonial stem cell (SSC) vitality and myosin heavy chain 9 (MYH9) protein expression. Linc00893 expression was analyzed in semen samples using reverse transcription‑quantitative PCR, revealing a significant downregulation in samples from individuals with AS compared with those from healthy subjects. This downregulation was found to be negatively correlated with parameters of sperm motility. To further understand the role of Linc00893, small interfering RNA was used to knockdown its expression in SSCs. This knockdown led to a marked decrease in cell vitality and an increase in apoptosis. Notably, Linc00893 knockdown was shown to inhibit MYH9 expression by competitively binding with microRNA‑107, a finding verified by dual‑luciferase reporter and RNA immunoprecipitation assays. Furthermore, using the GSE160749 dataset from the Gene Expression Omnibus database, it was revealed that MYH9 protein expression was downregulated in AS samples. Subsequently, lentiviral vectors were constructed to induce overexpression of MYH9, which in turn reduced SSC apoptosis and counteracted the apoptosis triggered by Linc00893 knockdown. In conclusion, the present study identified the role of Linc00893 in AS, particularly its regulatory impact on sperm motility, SSC vitality and MYH9 expression. These findings may provide information on the potential regulatory mechanisms in AS development, and identify Linc00893 and MYH9 as possible targets for diagnosing and treating AS‑related disorders.

The Role of microRNA in Spermatogenesis: Is There a Place for Fertility Preservation Innovation?

Oncological treatments have dramatically improved over the last decade, and as a result, survival rates for cancer patients have also improved. Quality of life, including concerns about fertility, has become a major focus for both oncologists and patients. While oncologic treatments are often highly effective at suppressing neoplastic growth, they are frequently associated with severe gonadotoxicity, leading to infertility. For male patients, the therapeutic option to preserve fertility is semen cryopreservation. In prepubertal patients, immature testicular tissue can be sampled and stored to allow post-cure transplantation of the tissue, immature germ cells, or in vitro spermatogenesis. However, experimental techniques have not yet been proven effective for restoring sperm production for these patients. MicroRNAs (miRNAs) have emerged as promising molecular markers and therapeutic tools in various diseases. These small regulatory RNAs possess the unique characteristic of having multiple gene targets. MiRNA-based therapeutics can, therefore, be used to modulate the expression of different genes involved in signaling pathways dysregulated by changes in the physiological environment (disease, temperature, ex vivo culture, pharmacological agents). This review discusses the possible role of miRNA as an innovative treatment option in male fertility preservation-restoration strategies and describes the diverse applications where these new therapeutic tools could serve as fertility protection agents.

Environmental and Genetic Traffic in the Journey from Sperm to Offspring

Recent advancements in the understanding of how sperm develop into offspring have shown complex interactions between environmental influences and genetic factors. The past decade, marked by a research surge, has not only highlighted the profound impact of paternal contributions on fertility and reproductive outcomes but also revolutionized our comprehension by unveiling how parental factors sculpt traits in successive generations through mechanisms that extend beyond traditional inheritance patterns. Studies have shown that offspring are more susceptible to environmental factors, especially during critical phases of growth. While these factors are broadly detrimental to health, their effects are especially acute during these periods. Moving beyond the immutable nature of the genome, the epigenetic profile of cells emerges as a dynamic architecture. This flexibility renders it susceptible to environmental disruptions. The primary objective of this review is to shed light on the diverse processes through which environmental agents affect male reproductive capacity. Additionally, it explores the consequences of paternal environmental interactions, demonstrating how interactions can reverberate in the offspring. It encompasses direct genetic changes as well as a broad spectrum of epigenetic adaptations. By consolidating current empirically supported research, it offers an exhaustive perspective on the interwoven trajectories of the environment, genetics, and epigenetics in the elaborate transition from sperm to offspring.

Functions and mechanism of noncoding RNA in regulation and differentiation of male mammalian reproduction

Noncoding RNAs (ncRNAs) are active regulators of a wide range of biological and physiological processes, including the majority of mammalian reproductive events. Knowledge of the biological activities of ncRNAs in the context of mammalian reproduction will allow for a more comprehensive and comparative understanding of male sterility and fertility. In this review, we describe recent advances in ncRNA-mediated control of mammalian reproduction and emphasize the importance of ncRNAs in several aspects of mammalian reproduction, such as germ cell biogenesis and reproductive organ activity. Furthermore, we focus on gene expression regulatory feedback loops including hormones and ncRNA expression to better understand germ cell commitment and reproductive organ function. Finally, this study shows the role of ncRNAs in male reproductive failure and provides suggestions for further research.

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.

Towards a Multi-Omics of Male Infertility

Infertility is a common problem affecting one in six couples and in 30% of infertile couples, the male factor is a major cause. A large number of genes are involved in spermatogenesis and a significant proportion of male infertility phenotypes are of genetic origin. Studies on infertility have so far primarily focused on chromosomal abnormalities and sequence variants in protein-coding genes and have identified a large number of disease-associated genes. However, it has been shown that a multitude of factors across various omics levels also contribute to infertility phenotypes. The complexity of male infertility has led to the understanding that an integrated, multi-omics analysis may be optimal for unravelling this disease. While there is a vast array of different factors across omics levels associated with infertility, the present review focuses on known factors from the genomics, epigenomics, transcriptomics, proteomics, metabolomics, glycomics, lipidomics, miRNomics, and integrated omics levels. These include: repeat expansions in AR, POLG, ATXN1, DMPK, and SHBG, multiple SNPs, copy number variants in the AZF region, disregulated miRNAs, altered H3K9 methylation, differential MTHFR, MEG3, PEG1, and LIT1 methylation, altered protamine ratios and protein hypo/hyperphosphorylation. This integrative review presents a step towards a multi-omics approach to understanding the complex etiology of male infertility. Currently only a few genetic factors, namely chromosomal abnormalities and Y chromosome microdeletions, are routinely tested in infertile men undergoing intracytoplasmic sperm injection. A multi-omics approach to understanding infertility phenotypes may yield a more holistic view of the disease and contribute to the development of improved screening methods and treatment options. Therefore, beside discovering as of yet unknown genetic causes of infertility, integrating multiple fields of study could yield valuable contributions to the understanding of disease development. Future multi-omics studies will enable to synthesise fragmented information and facilitate biomarker discovery and treatments in male infertility.

Identification of hub genes and biological mechanisms underlying the pathogenesis of asthenozoospermia and chronic epididymitis

Objective: Asthenozoospermia (AZS) is one of the most common causes of male fertility, affecting family wellbeing and population growth. Chronic epididymitis (CE) is a common and lingering inflammatory disease in the scrotum. Inflammation in the epididymis has a severe impact on sperm motility. This study aimed to explore the genetic profile and critical pathways involved in the pathological mechanisms of AZS and CE, and discover potential biomarkers. Methods: Genomic datasets of AZS and CE were obtained from the Gene Expression Omnibus (GEO) database, and relevant differentially expressed genes (DEGs) were identified. GO and pathway enrichment analyses, construction of a protein-protein interaction network, and receiver operator characteristic curve analysis were conducted. The expression profile of hub genes was validated in immunohistochemical data and testicular cell data. Immune infiltration, miRNA-hub gene interactions, and gene-disease interactions were explored. The mRNA levels of hub genes were further measured by qRT-PCR. Results: A total of 109 DEGs were identified between the AZS/CE and healthy control groups. Pathways of the immune system, neutrophil degranulation, and interleukin-4 and interleukin-13 signaling were enriched in AZS and CE. Five hub genes (CD300LB, CMKLR1, CCR4, B3GALT5, and CTSK) were selected, and their diagnostic values were validated in AZS, CE, and independent validation sets (area under the curve >0.7). Furthermore, the five-hub gene signature was well characterized in testicular immunohistochemical staining and testicular cells from healthy controls. Immune infiltration analysis showed that infiltration of CD8⁺ cells and T helper cells was significantly related to the expression level of five hub genes. In addition, a miRNA-hub gene network and interaction of other diseases were displayed. The mRNA levels of hub genes (CD300LB, CMKLR1, CCR4, and B3GALT5) were significantly elevated in the patient group. The mRNA level of CTSK also showed a similar trend. Conclusion: Our study uncovered the genetic profile involved in AZS and CE, and elucidated enriched pathways and molecular associations between hub genes and immune infiltration. This finding provides novel insight into the common pathogenesis of both diseases as well as the potential biomarkers for CE-associated AZS.

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.

Histological and immunohistochemical outcomes after microdissection TESE in contrast with hormonal profile, testis volume and genetics in patients with azoospermia

A limited number of individuals with non-obstructive azoospermia (NOA) may recover spermatozoa through traditional testicular sperm extraction (TESE) techniques. There is an ongoing debate over the effectiveness of microdissection TESE compared to standard TESE methods. Microdissection TESE (micro-TESE) techniques enable the identification of spermatogenesis foci in non-obstructive forms of azoospermia. Only histological examination can provide an objective and definitive assessment of the testicular phenotype. This study aimed to evaluate the correlation between histopathological findings after microdissection TESE (micro-TESE) and the predictive role of various factors in determining the success of sperm retrieval. We evaluated 24 patients with azoospermia who underwent micro-TESE and considered the patient's hormonal profile, testis ultrasound, genetic evaluation, histology, and immunohistology (PLAP antibody) of collected testis biopsies. The preoperative blood FSH level, in conjunction with other parameters, may aid in the prediction of micro-TESE success. Sensitivity increases, and specificity decreases with higher FSH levels. Furthermore, testicular volume and FSH levels are typically normal in patients with maturation arrest. In conclusion, hormones, ultrasound evaluation of the testicles, testis volume, and available genetic tests have a predictive value in differentiating obstructive azoospermia (OA) from NOA with various sensitivity and specificity rates. Histological and immunohistochemical evaluation establishes the testicular phenotype accurately and guides patient management.

Elevated plasma miR-210 expression is associated with atypical genitalia in patients with 46,XY differences in sex development

BACKGROUND

Differences of sex development (DSD) is a term used for conditions in which the chromosomal, gonadal or phenotypical sex is atypical. 46,XY DSD patients frequently present undervirilized external genitalia. The expression of different miRNAs in many organs of the male genital system has been reported, and these miRNAs have been associated with testicular function and its disorders, but no description has been related to DSD conditions. This study aimed to evaluate the plasma expression of miR-210 in 46,XY DSD patients who presented atypical genitalia at birth.

METHODS

Eighteen 46,XY DSD patients who presented atypical genitalia (undescended testis and/or hypospadias, bifid scrotum or micropenis) at birth and 36 male control individuals were selected. Plasma levels of miR-210 and reference miR-23a were measured using RT-qPCR and the data were analysed by the 2^-ΔCt method.

RESULTS

MiR-210 plasma levels were significantly higher in 46,XY DSD patients with atypical genitalia than in male control subjects (p = 0.0024). A positive association between miR-210 levels and the presence of cryptorchidism and hypospadias (p = 0.0146 and p = 0.0223) was found in these patients. Significantly higher levels of miR-210 were observed in patients with 46,XY DSD and cryptorchidism than in control subjects (p = 0.0118). These results are in agreement with previous literature reports, in which increased levels of miR-210 expression were observed in human testicular tissue from adult males with undescended testes in comparison with samples of descended testes.

CONCLUSION

Our study showed a positive association between the presence of atypical genitalia and plasma levels of miR-210 expression in the group of patients with 46,XY DSD of unknown aetiology studied. These findings contribute to reveal a new perspective on the role of miRNAs in the development of male external genitalia and the broad spectrum of phenotypes presented by patients with 46,XY DSD.

Investigation of Sperm and Seminal Plasma Candidate MicroRNAs of Bulls with Differing Fertility and In Silico Prediction of miRNA-mRNA Interaction Network of Reproductive Function

Simple Summary

The objective of this study was to identify differentially expressed (DE) sperm and seminal plasma microRNAs (miRNAs) in high- and low-fertile Holstein bulls (four bulls per group), integrate miRNAs to their target genes, and categorize target genes based on predicted biological processes. Out of 84 bovine-specific, prioritized miRNAs analyzed by RT-PCR, 30 were differentially expressed in high-fertile sperm and seminal plasma compared to low-fertile sperm and seminal plasma, respectively (p ≤ 0.05, fold regulation ≥5 magnitudes). Interestingly, expression levels of DE-miRNAs in sperm and seminal plasma followed a similar pattern. Highly scored integrated genes of DE-miRNAs predicted various biological and molecular functions, cellular process, and pathways. Further in silico analysis revealed categorized genes may have a plausible association with pathways regulating sperm structure and function, fertilization, and embryo and placental development. In conclusion, highly DE-miRNAs in bovine sperm and seminal plasma could be used as a tool for predicting reproductive functions. Since the identified miRNA-mRNA interactions were mostly based on predictions from public databases, the causal regulations of miRNA-mRNA and the underlying mechanisms require further functional characterization in future studies.

Abstract

Recent advances in high-throughput in silico techniques portray experimental data as exemplified biological networks and help us understand the role of individual proteins, interactions, and their biological functions. The objective of this study was to identify differentially expressed (DE) sperm and seminal plasma microRNAs (miRNAs) in high- and low-fertile Holstein bulls (four bulls per group), integrate miRNAs to their target genes, and categorize the target genes based on biological process predictions. Out of 84 bovine-specific, prioritized miRNAs analyzed by RT-PCR, 30 were differentially expressed in high-fertile sperm and seminal plasma compared to low-fertile sperm and seminal plasma, respectively (p ≤ 0.05, fold regulation ≥ 5 magnitudes). The expression levels of DE-miRNAs in sperm and seminal plasma followed a similar pattern. Highly scored integrated genes of DE-miRNAs predicted various biological and molecular functions, cellular process, and pathways. Further, analysis of the categorized genes showed association with pathways regulating sperm structure and function, fertilization, and embryo and placental development. In conclusion, highly DE-miRNAs in bovine sperm and seminal plasma could be used as a tool for predicting reproductive functions. Since the identified miRNA-mRNA interactions were mostly based on predictions from public databases, the causal regulations of miRNA-mRNA and the underlying mechanisms require further functional characterization in future studies.

Further Insights on RNA Expression and Sperm Motility

Asthenozoospermia is one of the main causes of male infertility and it is characterized by reduced sperm motility. Several mutations in genes that code for structural or functional constituents of the sperm have already been identified as known causes of asthenozoospermia. In contrast, the role of sperm RNA in regulating sperm motility is still not fully understood. Consequently, here we aim to contribute to the knowledge regarding the expression of sperm RNA, and ultimately, to provide further insights into its relationship with sperm motility. We investigated the expression of a group of mRNAs by using real-time PCR (CATSPER3, CFAP44, CRHR1, HIP1, IQCG KRT34, LRRC6, QRICH2, RSPH6A, SPATA33 and TEKT2) and the highest score corresponding to the target miRNA for each mRNA in asthenozoospermic and normozoospermic individuals. We observed a reduced expression of all mRNAs and miRNAs in asthenozoospermic patients compared to controls, with a more accentuated reduction in patients with progressive sperm motility lower than 15%. Our work provides further insights regarding the role of RNA in regulating sperm motility. Further studies are required to determine how these genes and their corresponding miRNA act regarding sperm motility, particularly KRT34 and CRHR1, which have not previously been seen to play a significant role in regulating sperm motility.

MicroRNA expression in male infertility

Male infertility is a multifactorial disorder that involves different physiopathological mechanisms and multiple genes. In this sense, we analyse the role of miRNAs in this pathology. Gene expression analysis can provide relevant information to detect biomarkers, signalling pathways, pathologic mechanisms, and potential therapeutic targets for the disease. In this review, we describe four miRNA microarrays related to patients who present infertility diseases, including azoospermia, asthenozoospermia, and oligoasthenozoospermic. We selected 13 miRNAs with altered expressions in testis tissue (hsa-miR-122-5p, hsa-miR-145-5p, hsa-miR-16-5p, hsa-miR-193a-3p, hsa-miR-19a-3p, hsa-miR-23a-3p, hsa-miR-30b-5p, hsa-miR-34b-5p, hsa-miR-34c-5p, hsa-miR-374b-5p, hsa-miR-449a, hsa-miR-574-3p and hsa-miR-92a-3p), and systematically examine the mechanisms of four relevant miRNAs (hsa-miR-16-5p, hsa-miR-19a-3p, hsa-miR-92a-3p and hsa-miR-30b-5p) which we found that regulated a large number of proteins. An interaction network was generated, and its connections allowed us to identify signalling pathways and interactions between proteins associated with male infertility. In this way, we confirm that the most affected and relevant pathway is the PI3K-Akt signalling.

Localisation and in silico based functional analysis of miR-202 in bull testis

Bull fertility is pivotal to the prosperity of the cattle industry worldwide. miR‐202 has been shown to be gonad specific and to have key roles in gonad function in different species. To further understand the involvement of miR‐202 in bull reproduction, this study aimed to establish its localization in bovine testicular tissue and to identify putative biological functions using bioinformatics approaches. We assessed the miR‐202 expression in paraffin‐embedded tissue samples collected form an abattoir using in situ hybridization. miR‐202 was present in Sertoli cells and in germ cells at different stages of development. Using available databases, a total of 466 predicted gene targets of miR‐202 were identified. Functional annotation revealed that miR‐202 target genes were mainly associated with protein modification and phosphorylation processes as well as longevity regulating pathway. Moreover, genes in the longevity regulating pathway mapped to PI3K/Akt/mTOR pathway which is involved in promoting proliferation of testicular cells and spermatogenesis. These findings suggest that miR‐202 plays important roles in regulating proliferation and viability of testicular cells including somatic and germ cells.

miR-199-5p regulates spermiogenesis at the posttranscriptional level via targeting Tekt1 in allotriploid crucian carp

BACKGROUND

Sperm abnormalities are one of the primary factors leading to male sterility, but their pathogenesis is still unclear. Although miRNAs are suggested to exert important roles in the regulation of spermatogenesis at both transcriptional and posttranscriptional levels, little is currently known regarding the regulation of sperm flagella assembly by microRNAs (miRNAs). The role of miRNAs in the development of sperm abnormalities in sterile triploid fish has not been studied.

RESULTS

In this study, we found that miR-199-5p was widely expressed in all detected tissues of different-ploidy crucian carp. As one of the testis-specific candidate markers, Tekt1 was predominantly expressed in the testis. Quantitative real-time PCR (qRT-PCR) analyses showed that the expression trend of miR-199-5p was exactly opposite to that of Tekt1. Through bioinformatics analysis, we identified a putative miR-199-5p binding site in the Tekt1 mRNA. We further identified Tekt1 as a target of miR-199-5p using luciferase reporter assay. Finally, we confirmed that miR-199-5p was necessary for sperm flagellar assembly and spermatogenesis in vivo via intraperitoneal injection of miR-199-5p antagomir or agomir in diploid red crucian carp. Moreover, miR-199-5p gain-of-function could lead to spermatids apoptosis and abnormal spermatozoa structure, which is similar to that of allotriploid crucian carp.

CONCLUSIONS

Our studies suggested that abnormally elevated miR-199-5p inhibited the sperm flagella formation in spermiogenesis by negatively regulating the expression of Tekt1, thereby causing sperm abnormalities of male allotriploid crucian carp.

Epigenetics and Testicular Cancer: Bridging the Gap Between Fundamental Biology and Patient Care

Testicular cancer is the most common solid tumor affecting young males. Most testicular cancers are testicular germ cell tumors (TGCTs), which are divided into seminomas (SGCTs) and non-seminomatous testicular germ cell tumors (NSGCTs). During their development, primordial germ cells (PGCs) undergo epigenetic modifications and any disturbances in their pattern might lead to cancer development. The present study provides a comprehensive review of the epigenetic mechanisms–DNA methylation, histone post-translational modifications, bivalent marks, non-coding RNA–associated with TGCT susceptibility, initiation, progression and response to chemotherapy. Another important purpose of this review is to highlight the recent investigations regarding the identification and development of epigenetic biomarkers as powerful tools for the diagnostic, prognostic and especially for epigenetic-based therapy.

The protective effect of C-phycocyanin in male mouse reproductive system

C-phycocyanin from Spirulina platensis has pharmacological effects such as anti-oxidation, anti-cancer, anti-inflammatory and anti-atherosclerosis activities as well as liver and kidney protection. However, there is little research on C-phycocyanin applied in the field of reproductive medicine, and it is therefore the focus of the current study. In this study, a GC-1 spg cell model and male mouse reproductive injury model were constructed by TNF α + Smac mimetic + zVAD-fmk (TSZ) and cyclophosphamide (Cy), respectively. It has been proved that C-phycocyanin can increase cell viability and reduce cell death in GC-1 spg cells induced by TSZ. C-phycocyanin could protect the reproductive system of male mice from cyclophosphamide, improve spermatogenesis, sperm quality and fertility, increase the release of testosterone, stabilize the feedback regulation mechanism, and ensure the spermatogenic ability of mice. It could also improve the ability of anti-oxidation. In addition, C-phycocyanin could play a protective role by down-regulating RIPK1, RIPK3, and p-MLKL to inhibit the necroptotic signaling pathway. These results suggest that C-phycocyanin could protect GC-1 spg cells and the reproductive system of male mice from TSZ and cyclophosphamide, and the protective mechanism may be achieved by inhibiting the signal pathway of necroptosis. Therefore, C-phycocyanin could serve as a promising reproductive system protective agent. C-phycocyanin may enter public life as a health product in the future.

MiRNA-34c Regulates Bovine Sertoli Cell Proliferation, Gene Expression, and Apoptosis by Targeting the AXL Gene

Simple Summary

Fertility is one of the essential reproduction traits of bulls, and accurate prediction of fertility potential using a semen sample from a donor bull for artificial insemination is crucial to achieve consistently high reproductive efficiency. Somatic cells, such as Sertoli cells and Leydig cells, are important in testis formation and provide a nurturing and regulatory environment for spermatogenesis. Furthermore, it was suggested that non-coding RNAs, such as microRNAs, long non-coding RNAs, circular RNAs, and Piwi-interacting RNA, function as important regulators of gene expression at post-transcriptional level in spermatogenesis. In this study, microRNA-34c was verified to specifically regulate the AXL gene by targeting a sequence in the 3’ UTR; miRNA-34c can also influence the proliferation, apoptosis, and relative abundance of the transcript of male-reproduction-related genes. Therefore, microRNA-34c can be considered an essential regulator in the process of bull spermatogenesis. These results identify a key microRNA and functional genes in the process of cattle male reproduction, providing useful information for future marker-assisted selection of bulls with excellent sperm quality.

Abstract

MicroRNAs (miRNAs) play significant roles in mammalian spermatogenesis. Sertoli cells can provide a stable microenvironment and nutritional factors for germ cells, thus playing a vital role in spermatogenesis. However, few studies elucidate the regulation of bovine testicular Sertoli cells by miRNAs. Here, we have reported that miRNA-34c (miR-34c) regulates proliferation, apoptosis, and relative transcripts abundance gene in bovine Sertoli cells. In bovine Sertoli cells, overexpression of miR-34c inhibited proliferation and relative abundance of gene transcripts while promoting apoptosis of Sertoli cells, and the effects were the opposite when miR-34c was knocked down. Receptor tyrosine kinase (AXL) was identified as a direct target gene of miR-34c in Sertoli cells, validated by analysis of the relative abundance of AXL transcript and dual-luciferase reporter assay. The relative abundance of the transcript of genes related to male reproduction in Sertoli cells was changed after the AXL gene was overexpressed, as demonstrated by the RT2 Profiler PCR Array results. In summary, miR-34c specifically regulated the AXL gene by targeting a sequence in the 3′-UTR, which could influence proliferation, apoptosis, and relative abundance of the transcript of male reproduction-related genes. Therefore, miR-34c could be considered an essential regulator in the process of bull spermatogenesis.