MicroRNA expression in infertile men: its alterations and effects

Transcriptome Analysis Reveals Spermatogenesis-Related CircRNAs and LncRNAs in Goat Spermatozoa

Mammalian spermatozoa comprises both coding and non-coding RNAs, which are traditionally believed to be a residual of spermatogenesis. The differential expression level of spermatozoal RNAs is also observed between fertile and infertile human, thereby anticipated as potential molecular marker of male fertility. This study investigated the transcriptome profile of goat (Capra hircus) spermatozoa. The sperm transcriptome was analyzed by three different methods viz. RLM-RACE, long-read RNA sequencing (RNAseq) in Nanopore™ platform, and short-read RNAseq in Illumina™ platform. The Illumina™ sequencing discovered 16,604 transcripts with 357 mRNAs having FPKM (fragments per kilobase per million mapped reads) of more than five. The spermatozoal RNA suite included mRNA (94%), rRNA (3%), miscRNA (1%), circRNA (1%), miRNA (1%), etc. This study also predicted circRNAs (127), lncRNAs (655), and imprinted genes (160) that have potential role in male reproduction. The gene ontology analysis revealed the involvement of spermatozoal RNA in regulating male meiosis (TET3, STAT5B), capacitation (ACRBP, CATSPER4), sperm motility (GAS8, TEKT2), spermatogenesis (ADAMTS2, CREB3L4), etc. The spermatozoal RNA were also associated with different biological pathways viz. Wnt signaling pathway, cAMP signaling pathway, AMPK signaling pathway, and MAPK signaling pathways having potential role in spermatogenesis. Overall, this study enlightened the suite of spRNA transcripts in goat and their relevance in male fertility for diagnostic approach.

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.

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).

Normospermic Patients Infected With Ureaplasma parvum: Role of Dysregulated miR-122-5p, miR-34c-5, and miR-141-3p

Background

Ureaplasma parvum (UP) is a causative agent of non-gonococcal urethritis, involved in the pathogenesis of prostatitis and epididymitis, and it could impair human fertility. Although UP infection is a frequent cause of male infertility the study evidence assessing their prevalence and the association in patients with infertility is still scarce. The molecular processes leading to defects in spermatozoa quality are not completely investigated. MicroRNAs (miRNAs) have been extensively reported as gene regulatory molecules on post-transcriptional levels involved in various biological processes such as gametogenesis, embryogenesis, and the quality of sperm, oocyte, and embryos.

Methods

Therefore, the study design was to demonstrate that miRNAs in body fluids like sperm could be utilized as non-invasive diagnostic biomarkers for pathological and physiological conditions such as infertility. A post-hoc bioinformatics analysis was carried out to predict the pathways modulated by the miRNAs dysregulated in the differently motile spermatozoa.

Results

Here it is shown that normospermic patients infected by UP had spermatozoa with increased quantity of superoxide anions, reduced expression of miR-122-5p, miR-34c-5, and increased miR-141-3p compared with non-infected normospermic patients. This corresponded to a reduction of sperm motility in normospermic infected patients compared with normospermic non-infected ones. A target gene prediction presumed that an essential role of these miRNAs resided in the regulation of lipid kinase activity, accounting for the changes in the constitution of spermatozoa membrane lipids caused by UP.

Conclusions

Altogether, the data underline the influence of UP on epigenetic mechanisms regulating spermatozoa motility.

Identification of ITPR1 gene as a novel target for hsa-miR-34b-5p in non-obstructive azoospermia: a Ca2+/apoptosis pathway cross-talk

MiR-34b-5p has been reported as a non-invasive diagnostic biomarker for infertility. However, no gene targets regulating the mechanism of cation of this miRNA are known. In this study, using gene set enrichment analysis the Inositol 1,4,5-Trisphosphate Receptor Type 1 (ITPR1) gene was identified as the sole target for hsa-miR-34b-5p, and found significantly overexpressed in non-obstructive azoospermia (NOA) patients. This finding was confirmed by qRT-PCR on fresh testicular tissues from NOA patients. Then, pathway enrichment analysis as well as the diagnostic value analysis of hsa-miR-34b-5p/ITPR1 indicated ITPR1 as a hub gene in the calcium (Ca2+)-apoptosis pathway, and a valuable predictive biomarker for NOA. Moreover, gene expression and histological assays showed the association of the effects of ITPR1's increased expression on spermatogenesis failure through induction of apoptosis in NOA patients. These data suggested that the hsa-miR-34b-5p/ITPR1 axis could serve as a potential regulatory predictive biomarker for human spermatogenesis through the Ca2+-apoptosis pathway cross-talk.

Reduced expression of miR-221 is associated with the pro-apoptotic pathways in spermatozoa of oligospermia men

Oligospermia and asthenozoospermia, both frequent, can lead to male infertility. Oligospermia might be viewed as a milder form of azoospermia because the same mutations that produce azoospermia in some individuals also create oligospermia in other individuals. In this, we looked at different characteristics of oligospermia men, counting the level of apoptosis and a few related apoptotic and oxidative stress components, and compared them to solid controls. In this study, semen samples from healthy fertile men (n = 35) and oligospermia (n = 35) were collected, and sperm death rates in both groups were examined using flow cytometry. Also, gene expression of apoptotic and anti-apoptotic markers and miR-221 were investigated (Real-Time PCR). Moreover, for the evaluation of catalase and SOD activity and anti-inflammatory cytokines, including IL-10 and TGF-β, the specific ELISA kits and procedures were applied. As a result, higher gene and protein expression levels of PTEN, P27, and P57 were observed in patients with oligospermia. In contrast, lower mRNA expression of AKT and miR-221 was detected in this group. In addition, IL-10, TGF-β, and catalase activity were suppressed in the oligospermia group compared with healthy men samples. Moreover, the frequency of apoptosis of sperm cells is induced in patients. In conclusion, apoptosis-related markers, PTEN, and the measurement of significant and efficient oxidative stress markers like SOD and catalase in semen plasma could be considered as the critical diagnostic markers for oligospermia. Future studies will be better able to treat oligospermia by showing whether these indicators are rising or falling.

Identification of a valuable gene network for the diagnosis and treatment of non-obstructive azoospermia: in-silico analyses - experimental research

Introduction

Non-obstructive azoospermia (NOA) is an etiology of infertility in men. NOA may have various classifications; however, hypogonadotropic hypogonadism can be regarded as a class of NOA associated with genetic factors. Former studies have shown that noncoding RNA (ncRNA) plays an essential role in NOA incidence, but few studies have been performed on the NOA-related ncRNA interaction network. In the current study, genes, NOA-related microRNA (miRNA), and circular RNA (circRNA) were found by bioinformatics methods to offer a new perspective on NOA treatment.

Methods

The gonadotropin-releasing hormone receptor (GnRHR)-related protein-protein interaction (PPI) network was extracted by searching in 'string-database'. GO, KEGG, and Enrichr databases were used to identify pathways, molecular function, and biological processing. Four databases, including TargetScan, mirDIP, miRmap, and miRWalk, were used to extract miRNAs. At last, the circ2GO, circBase, and literature were used to identify circRNAs and their genes.

Results

The current study identified the four proteins associated with the GnRHR signaling; eight shared miRNAs that affect the expression of found proteins and 25 circRNAs and their origin genes that regulate the miRNAs' function.

Conclusion

The two miRNAs, hsa-miR-134-3p and hsa-miR-513C-3p, the three genes, VCAN, NFATC3, and PRDM5, and their associated circRNAs can perform as a valuable gene network in the diagnosis and treatment of NOA pathogenesis.

The physiological functions and therapeutic potential of exosomes during the development and treatment of polycystic ovary syndrome

Polycystic ovary syndrome is a very common disease of gynecological endocrine, accompanied by irregular menstruation, hyperandrogenism, metabolic abnormalities, reproductive disorders and other clinical symptoms, which seriously endangers women's physical and mental health, but its etiology and pathogenesis are not completely clear. Recently, the contribution of exosomes to the diagnosis and treatment of various diseases in the biomedical field has attracted much attention, including PCOS. Exosomes are extracellular vesicles secreted by cells, containing various biologically active molecules such as cell-specific proteins, lipids, and nucleic acids. They are important signaling regulators in vivo and widely participate in various physiopathological processes. They are new targets for disease diagnosis and treatment. Considering the important role of non-coding RNAs during the development and treatment of PCOS, this article takes exosomal miRNAs as the breakthrough point for elucidating the physiological functions and therapeutic potential of exosomes during the development and treatment of PCOS through analyzing the effects of exosomal miRNAs on ovarian follicle development, hormone secretion, oxidative stress, inflammatory response and insulin resistance, thus providing new research directions and theoretical basis for PCOS pathogenesis, clinical diagnosis and prognosis improvement.

Association between microRNA expression and risk of male idiopathic infertility in Iraq

OBJECTIVE

The World Health Organization defines infertility as the inability to get pregnant after 12 months of unprotected sexual activity. This study was conducted to estimate the levels of gene expression for two mature miRNAs (i.e., miR-122 and miR-34c-5p) to evaluate susceptibility to male infertility.

METHODS

This study included 50 male patients with idiopathic infertility who were admitted to hospital from the period November 2021 to May 2022 and another group consisting of 50 apparently healthy individuals used as controls.

RESULTS

miR-122 level was significantly highest in azoospermia and followed by oligospermia, 39.22 (31.88) versus 37.34 (20.45), respectively. In addition, there was a very significant difference in miR-34c-5p levels between the study groups (p<0.05).

CONCLUSION

Two miRNAs, namely, miR-34c-5p and miR-122, can be used as predictive and diagnostic biomarkers for infertility.

Dietary Sugar Shifts Mitochondrial Metabolism and Small RNA Biogenesis in Sperm

Aims: Increasing concentrations of dietary sugar results in a linear accumulation of triglycerides in male Drosophila, while inducing a U-shaped obesity response in their offspring. Here, using a combination of proteomics and small RNA (sRNA) sequencing, we aimed at understanding the molecular underpinning in sperm for such plasticity. Results: Proteomic analysis of seminal vesicles revealed that increasing concentrations of dietary sugar resulted in a bell-shaped induction of proteins involved in metabolic/redox regulation. Using stains and in vivo redox reporter flies, this pattern could be explained by changes in sperm production of reactive oxygen species (ROS), more exactly mitochondria-derived H₂O₂. By quenching ROS with the antioxidant N-acetyl cysteine and performing sRNA-seq on sperm, we found that sperm miRNA is increased in response to ROS. Moreover, we found sperm mitosRNA to be increased in high-sugar diet conditions (independent of ROS). Reanalyzing our previously published data revealed a similar global upregulation of human sperm mitosRNA in response to a high-sugar diet, suggesting evolutionary conserved mechanisms. Innovation: This work highlights a fast response to dietary sugar in mitochondria-produced H₂O₂ in Drosophila sperm and identifies redox-sensitive miRNA downstream of this event. Conclusions: Our data support a model where changes in the sperm mitochondria in response to dietary sugar are the primary event, and changes in redox homoeostasis are secondary to mitochondrial ROS production. These data provide multiple candidates for paternal intergenerational metabolic responses as well as potential biomarkers for human male fertility.

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.

Using microRNAs as molecular biomarkers for the evaluation of male infertility

Infertility is a multiplex disorder in the reproductive system, and men are responsible for more than half of the cases. Nowadays, semen analysis has been considered the critical assessment test to diagnose infertile men; however, it has limitations so that the cause behind infertility in 40% of infertile men is unrevealed. Weaknesses of semen assessment indicate a global need for novel and better diagnostic tools and biomarkers. MicroRNAs are short (about 18-22 nucleotide length) non-coding RNAs that control most (>60%) of our protein-coding genes post-transcriptionally. These molecules are aberrant in the body fluids, and abnormal alterations in their expression level can signify a specific disease such as infertility. Therefore, microRNAs can be novel candidate biomarkers that can diagnose different types of male infertility, including azoospermia, oligozoospermia, asthenozoospermia and teratozoospermia. This narrative review aimed to collect and sum up new papers published about the significant role of microRNAs in different male infertility categories.

MicroRNA-449a Suppresses Mouse Spermatogonia Proliferation via Inhibition of CEP55

At present, infertile patients with maturation arrest (MA) are difficult to obtain mature sperm. Spermatogenesis and its molecular mechanism are still not clear. Patients with MA and normal spermatogenesis (NS) were collected. iTRAQ-based proteomic approach was performed to reveal the different proteins between them. To validate the confidence of proteome data, the individual samples were analyzed by Western blotting (WB), quantitative polymerase chain reaction (qPCR), and immunofluorescence. The miR-449a and CEP55 were determined by Luciferase assay. Mouse GC-1 cells were transfected with CEP55 siRNAs, miR-449a mimic, or inhibitor, and cell proliferation was determined. Compared with NS, 27 proteins were differentially expressed in MA, and CEP55 protein was the most significant difference. WB and qPCR showed that CEP55 levels were significantly elevated in NS than MA. In transfected cells, overexpression of miR-449a and knockdown of CEP55 both downregulated CEP55 expression and decreased cell proliferation. miR-449a suppresses mouse spermatogonia proliferation via inhibition of CEP55.

H. Anholts J, Blijleven L, Meuleman T, van Beelen E, van der Hoorn MLP, Claas FHJ. Optimization of microRNA Acquirement from Seminal Plasma and Identification of Diminished Seminal microRNA-34b as Indicator of Low Semen Concentration

About 10–15% of couples who want to conceive suffer from subfertility, while in 30% of these cases, a male factor plays a role. Levels of particular microRNAs in seminal plasma, including those involved in spermatogenesis, may serve as an indicative parameter for subfertility. We first optimized a protocol for acquiring microRNAs from seminal plasma. Next, using a test-validation strategy in a male cohort, we aimed to identify microRNAs of which the levels are related to semen motility and concentration. By qPCR, 742 microRNAs were profiled in three normozoospermic samples, three seminal samples with a low semen motility (asthenozoospermia), and three with a low semen concentration (oligozoospermia). MicroRNAs showing significant differences between groups were further validated in a second cohort consisting of 40 samples with normozoospermia (control group), 47 samples with asthenozoospermia, and 19 samples with oligozoospermia (of which 74% also low motility). Highest microRNA yields were obtained with the Biofluids RNA extraction kit, with inclusion of MS2 RNA carrier and proteinase K treatment to the protocol, and when 50 µL of seminal plasma was used as input. Exosome isolation prior to RNA extraction did not lead to enhanced yields. In the test cohort, 236 microRNAs could be detected, of which 54 microRNAs showed a difference between groups. Five microRNAs were analyzed in the validation cohort. MiR-34b-5p levels in the control group were significantly higher compared to the asthenozoospermia group (p < 0.05) and compared to the oligozoospermia group (p < 0.001). We optimized microRNA acquirement from seminal plasma and identified microRNA levels in relation to semen concentration and motility. As recent human and mouse studies show that the miR-34 family is a marker of low semen concentration and is crucial in spermatogenesis, seminal plasma miR-34b-5p may represent a suitable candidate to study further as a marker of male subfertility.

CircRNA Role and circRNA-Dependent Network (ceRNET) in Asthenozoospermia

The role of circRNA in reproduction is under investigation. CircRNAs are expressed in human testis, spermatozoa (SPZ), and seminal plasma. Their involvement in embryo development has also been suggested. Asthenozoospermia, a common cause of male infertility, is characterized by reduced or absent sperm motility in fresh ejaculate. While abnormal mitochondrial function, altered sperm tail, and genomic causes have been deeply investigated, the epigenetic signature of asthenozoospermic derived SPZ still remains unexplored. CircRNAs may take part in the repertoire of differentially expressed molecules in infertile men. Considering this background, we carried out a circRNA microarray, identifying a total of 9,138 transcripts, 22% of them novel based and 83.5% with an exonic structure. Using KEGG analysis, we evaluated the circRNA contribution in pathways related to mitochondrial function and sperm motility. In order to discriminate circRNAs with a differential expression in SPZ with differential morphological parameters, we separated sperm cells by Percoll gradient and analyzed their differential circRNA payload. A bioinformatic approach was then utilized to build a circRNA/miRNA/mRNA network. With the aim to demonstrate a dynamic contribution of circRNAs to the sperm epigenetic signature, we verified their modulation as a consequence of an oral amino acid supplementation, efficacious in improving SPZ motility.