Male infertility and its genetic causes

Detection of AZF microdeletions and analysis of reproductive hormonal profiles in Hainan men undergoing assisted reproductive technology

BACKGROUND

Male infertility has become a global health problem, and genetic factors are one of the essential causes. Y chromosome microdeletion is the leading genetic factor cause of male infertility. The objective of this study is to investigate the correlation between male infertility and Y chromosome microdeletions in Hainan, the sole tropical island province of China.

METHODS

We analyzed the semen of 897 infertile men from Hainan in this study. Semen analysis was measured according to WHO criteria by professionals at the Department of Reproductive Medicine, the First Affiliated Hospital of Hainan Medical University, where samples were collected. Y chromosome AZF microdeletions were confirmed by detecting six STS markers using multiple polymerase chain reactions on peripheral blood DNA. The levels of reproductive hormones, including FSH, LH, PRL, T, and E2, were quantified using the enzyme-linked immunosorbent assay (ELISA).

RESULTS

The incidence of Y chromosome microdeletion in Hainan infertile men was 7.13%. The occurrence rate of Y chromosome microdeletion was 6.69% (34/508) in the oligozoospermia group and 7.71% (30/389) in the azoospermia group. The deletion of various types in the AZF subregion was observed in the group with azoospermia, whereas no AZFb deletion was detected in the oligozoospermia group. Among all patients with microdeletions, the deletion rate of the AZFc region was the higher at 68.75% (44 out of 64), followed by a deletion rate of 6.25% (4 out of 64) for the AZFa region and a deletion rate of 4.69% (3 out of 64) for the AZFb region. The deletion rate of the AZFa region was significantly higher in patients with azoospermia than in patients with oligozoospermia (0.51% vs. 0.39%, p < 0.001). In comparison, the deletion rate of the AZFc region was significantly higher in patients with oligozoospermia (3.08% vs. 6.30%, p < 0.001). Additionally, the AZFb + c subregion association deletion was observed in the highest proportion among all patients (0.89%, 8/897), followed by AZFa + b + c deletion (0.56%, 5/897), and exclusively occurred in patients with azoospermia. Hormone analysis revealed FSH (21.63 ± 2.01 U/L vs. 10.15 ± 0.96 U/L, p = 0.001), LH (8.96 ± 0.90 U/L vs. 4.58 ± 0.42 U/L, p < 0.001) and PRL (263.45 ± 21.84 mIU/L vs. 170.76 ± 17.10 mIU/L, p = 0.002) were significantly increased in azoospermia patients with microdeletions. Still, P and E2 levels were not significantly different between the two groups.

CONCLUSIONS

The incidence of AZF microdeletion can reach 7.13% in infertile men in Hainan province, and the deletion of the AZFc subregion is the highest. Although the Y chromosome microdeletion rate is distinct in different regions or populations, the regions mentioned above of the Y chromosome may serve an indispensable role in regulating spermatogenesis. The analysis of Y chromosome microdeletion plays a crucial role in the clinical assessment and diagnosis of male infertility.

Metabolomics of male infertility

This review explores the use of metabolomics in male infertility. Metabolomics, an evolving omics technology that targets the products of cellular metabolism, is valuable for elucidating underlying pathophysiology of many disorders including male infertility. The identification of reliable biomarkers is essential for accurate diagnosis and for developing precision therapeutics for those afflicted by reproductive dysfunction. Unfortunately, despite significant progress to date, the intricate relationships between these metabolic pathways and male infertility remain elusive. It is clear, however, that additional research is required to more fully characterize the role of metabolomics in this disorder and in the potential development of targeted therapies for precision medicine.

Discovery of a novel miRNA involved in the regulation of male infertility in zebrafish

Azoospermia and asthenospermia are common manifestations of male infertility, but it needs further studies to understand the intrinsic regulation mechanism. As a popular model organism, zebrafish is often used to assess reproductive complications. In this study, by analyzing miRNA transcriptome of the mature triploid zebrafish testis afflicted with spermatogenic dysfunctions, leading to the identification of 36 miRNAs that are differentially expressed in comparison with diploid, which are predicted to target 2737 genes. Subsequent functional annotation of these genes pinpointed two miRNAs might association with spermatogenesis. Inhibitory experiments showed that NC_007115.7.7_998413 inhibited conducts a substantial decline in sperm density, and conducted lower embryo fertilization rate than control. And putative target genes qRT-PCR evaluation showed that spata2 was significant down-regulate upon inhibited NC_007115.7.7_998413. In summary, this research positions newly identified miRNA NC_007115.7.998413 as a regulatory factor in male zebrafish reproductive development, enhancing our comprehension of the molecular regulated pathways involved in spermatogenesis.

Effect of icariin on the transformation efficiency of induced pluripotent stem cells into sperm cells in vitro

OBJECTIVE

To investigate the effect of icariin on the transformation efficiency of germ cell-like cells from mouse induced pluripotent stem cells into sperm cells in vitro.

METHODS

Firstly, mouse induced pluripotent stem cells were induced and cultured to transform into germ cell-like cells, and the primordial germ cell-like cells were identified by Western blot and RT-PCR. Then, different concentrations of icariin (0.1μg/mL, 1μg/mL, 10μg/mL and 100μg/mL) were added into the culture medium, and the obtained primitive germ cell-like cells were cultured, Western blot and RT-PCR were used to identify the obtained sperm cells, the transformation efficiency was compared.

RESULTS

The primordium germ cell-like cells obtained from mouse induced pluripotent stem cells in vitro specially expressed Oct-4 protein, C-kit protein, Mvh mRNA, Fragilis mRNA and Stella mRNA. The sperm cells were specially expressed VASA, SCP3 and γH2AX proteins. RT-PCR showed that the sperm cells were specially expressed Ddx4, Tp2 and Prm1 mRNA. Compared with the control group, the expression level of VASA protein (1.744±0.283, 2.882±0.373, 6.489±0.460), SCP3 protein (2.250±0.306, 7.058±0.521, 8.654±0.804), γH2AX protein (4.304±0.433, 5.713±0.339, 9.268±0.545), Ddx4 mRNA (1.374±0.145, 2.846±0.194, 4.021±0.154), Tp2 mRNA (1.358±0.130, 3.623±0.326, 5.811±0.390) and Prm1 mRNA (1.326±0.162, 3.487±0.237, 4.666±0.307) in 0.1μg/mL, 1μg/mL, 10μg/mL icariin experimental groups were all lower than that of VASA protein (10.560±0.413), SCP3 protein (13.804±0.642), γH2AX protein (11.874±0.464), Ddx4 mRNA (6.4005±0.361), Tp2 mRNA (7.314±0.256) and Prm1 mRNA (7.334±0.390) in 100μg/mL icariin experimental group.

CONCLUSIONS

Icariin can promote the transformation of mouse induced pluripotent stem cells into sperm cells in vitro, and it is concentration-dependent manner in a certain concentration range.

Current Progress in Stem Cell Therapy for Male Infertility

Infertility has become one of the most common issues worldwide, which has negatively affected society and infertile couples. Meanwhile, male infertility is responsible for about 50% of infertility. Accordingly, a great number of researchers have focused on its treatment during the last few years; however, current therapies such as assisted reproductive technology (ART) are not effective enough in treating male infertility. Because of their self-renewal and differentiation capabilities and unlimited sources, stem cells have recently raised great hope in the treatment of reproductive system disorders. Stem cells are undifferentiated cells that can induce different numbers of specific cells, such as male and female gametes, demonstrating their potential application in the treatment of infertility. The present review aimed at identifying the causes and potential factors that influence male fertility. Besides, we highlighted the recent studies that investigated the efficiency of stem cells such as spermatogonial stem cells (SSCs), embryonic stem cells (ESCs), very small embryonic-like stem cells (VSELs), induced pluripotent stem cells (iPSCs), and mesenchymal stem cells (MSCs) in the treatment of various types of male infertility.

Molecular genetic analysis of 1,980 cases of male infertility

The present study aimed to investigate the occurrence of chromosomal karyotype abnormalities and azoospermia factor (AZF) microdeletion on the long arm of the Y chromosome (Yq) in infertile men, and to determine their association with infertility to ultimately improve clinical outcomes in these patients. A total of 1,980 azoospermic and oligospermic men from the outpatient department of the Fujian Maternity and Child Health Hospital (Fuzhou, China) were recruited between January 2016 and December 2019. Peripheral blood was used for karyotype analysis; AZF microdeletion analysis of the Yq was performed using capillary electrophoresis. Among the 1,980 patients, 178 had chromosomal abnormalities (9.0%; 178/1,980), of whom 98 had an abnormal number of chromosomes. Among the abnormal karyotypes, the most common was 47, XXY (80/178; 44.9%). AZF microdeletion on the Yq occurred at a rate of 10.66% (211/1,980); the most common type was the AZFb/c deletion (sY1192; 140/211; 66.4%). The present findings showed that karyotype abnormalities and AZF gene microdeletion are important drivers of male infertility. Specifically, men with Yqh- and del(Y)(q11) had a higher risk of AZF microdeletion. These results suggested that patient treatment could be personalized based on routine molecular genetic analysis, which could further alleviate the economic and emotional burden of undergoing redundant or ineffective treatments.

Quantitative proteomics and phosphoproteomics reveal insights into mechanisms of ocnus function in Drosophila testis development

BACKGROUND

Testis is the only organ supporting sperm production and with the largest number of proteins and tissue-specific proteins in animals. In our previous studies, we have found that knockdown of ocnus (ocn), a testis-specific gene, resulted in much smaller testis with no germ cells in Drosophila melanogaster. However, the molecular consequences of ocn knockdown in fly testes are unknown.

RESULTS

In this study, through iTRAQ quantitative proteomics sequencing, 606 proteins were identified from fly abdomens as having a significant and at least a 1.5-fold change in expression after ocn knockdown in fly testes, of which 85 were up-regulated and 521 were down-regulated. Among the differential expressed proteins (DEPs), apart from those proteins involved in spermatogenesis, the others extensively affected biological processes of generation of precursor metabolites and energy, metabolic process, and mitochondrial transport. Protein-protein interaction (PPI) analyses of DEPs showed that several kinases and/or phosphatases interacted with Ocn. Re-analyses of the transcriptome revealed 150 differential expressed genes (DEGs) appeared in the DEPs, and their changing trends in expressions after ocn knockdown were consistent. Many common down-regulated DEGs and DEPs were testis-specific or highly expressed in the testis of D. melanogaster. Quantitative RT-PCR (qRT-PCR) confirmed 12 genes appeared in both DEGs and DEPs were significantly down-regulated after ocn knockdown in fly testes. Furthermore, 153 differentially expressed phosphoproteins (DEPPs), including 72 up-regulated and 94 down-regulated phosphorylated proteins were also identified (13 phosphoproteins appeared in both up- and down-regulated groups due to having multiple phosphorylation sites). In addition to those DEPPs associated with spermatogenesis, the other DEPPs were enriched in actin filament-based process, protein folding, and mesoderm development. Some DEPs and DEPPs were involved in Notch, JAK/STAT, and cell death pathways.

CONCLUSIONS

Given the drastic effect of the ocn knockdown on tissue development and testis cells composition, the differences in protein abundance in the ocn knockdown flies might not necessarily be the direct result of differential gene regulation due to the inactivation of ocn. Nevertheless, our results suggest that the expression of ocn is essential for Drosophila testis development and that its down-regulation disturbs key signaling pathways related to cell survival and differentiation. These DEPs and DEPPs identified may provide significant candidate set for future studies on the mechanism of male reproduction of animals, including humans.

Cholesterol-Amino-Phosphate (CAP) Derived Lipid Nanoparticles for Delivery of Self-Amplifying RNA and Restoration of Spermatogenesis in Infertile Mice

Male infertility caused by genetic mutations is an important type of infertility. Currently, there is no reliable method in the clinic to address this medical need. The emergence of mRNA therapy provides a possible strategy for restoring mutant genes in the reproductive system. However, effective delivery of mRNA to spermatocytes remains a formidable challenge. Here a series of cholesterol-amino-phosphate (CAP) lipids are reported by integrating three bioactive moieties into a geometric structure, which is favorable for mRNA delivery. The results demonstrate that CAP-derived lipid nanoparticles (CAP LNPs) can deliver RNA including traditional mRNA and self-amplifying RNA (saRNA) encoding DNA Meiotic Recombinase 1 (Dmc1) protein in spermatocytes and treat male infertility caused by the Dmc1 gene mutation. Notably, the delivery efficiency of CAP LNPs is significantly higher than that of the MC3 and ALC-0315 LNPs, which is consistent with the design of CAP molecules. More importantly, a single injection of CAP LNPs-saRNA can produce Dmc1 protein for an extended period, which restores the spermatogenesis in the Dmc1 gene knockout mouse model. Overall, this study proves the concept of LNPs for the delivery of mRNA to spermatocytes, which provides a unique method to probe male infertility caused by the genetic mutation.

Comparative Genomic Hybridization and Transcriptome Sequencing Reveal Genes with Gain in Acute Lymphoblastic Leukemia: JUP Expression Emerges as a Survival-Related Gene

Acute lymphoblastic leukemia (ALL) in children or adults is characterized by structural and numeric aberrations in chromosomes; these anomalies strongly correlate with prognosis and clinical outcome. Therefore, this work aimed to identify the genes present in chromosomal gain regions found more frequently in patients with acute lymphoblastic leukemia (ALL) and ALL-derived cell lines using comparative genomic hybridization (CGH). In addition, validation of the genes found in these regions was performed utilizing RNAseq from JURKAT, CEM, and SUP-B15 cell lines, as well as expression microarrays derived from a MILE study. Chromosomes with common gain zones that were maintained in six or more samples were 14, 17, and 22, in which a total of 22 genes were identified. From them, NT5C3B, CNP, ACLY, and GNB1L maintained overexpression at the mRNA level in the cell lines and in patients with ALL. It is noteworthy that SALL2 showed very high expression in T-ALL, while JUP was highly expressed in B-ALL lineages. Interestingly, the latter correlated with worse survival in patients. This provided evidence that the measurement of these genes has high potential for clinical utility; however, their expressions should first be evaluated with a sensitive test in a more significant number of patients.

iPSCs derived from infertile men carrying complex genetic abnormalities can generate primordial germ-like cells

Despite increasing insight into the genetics of infertility, the developmental disease processes remain unclear due to the lack of adequate experimental models. The advent of induced pluripotent stem cell (iPSC) technology has provided a unique tool for in vitro disease modeling enabling major advances in our understanding of developmental disease processes. We report the full characterization of complex genetic abnormalities in two infertile patients with either azoospermia or XX male syndrome and we identify genes of potential interest implicated in their infertility. Using the erythroblasts of both patients, we generated primed iPSCs and converted them into a naive-like pluripotent state. Naive-iPSCs were then differentiated into primordial germ-like cells (PGC-LCs). The expression of early PGC marker genes SOX17, CD-38, NANOS3, c-KIT, TFAP2C, and D2-40, confirmed progression towards the early germline stage. Our results demonstrate that iPSCs from two infertile patients with significant genetic abnormalities are capable of efficient production of PGCs. Such in vitro model of infertility will certainly help identifying causative factors leading to early germ cells development failure and provide a valuable tool to explore novel therapeutic strategies.

Stem cells technology as a platform for generating reproductive system organoids and treatment of infertility-related diseases

In recent years, stem cells have known as a helpful biological tool for the accurate diagnosis, treatment and recognition of diseases. Using stem cells as biomarkers have presented high potential in the early detection of many diseases. Another advancement in stem cell technology includes stem cell derived organoids model that could be a promising platform for diagnosis and modeling different diseases. Furthermore, therapeutic capabilities of stem cell therapy have increased hope in the face of different disability managements. All of these technologies are also widely used in reproductive related diseases especially in today's world that many couples encounter infertility problems. However, with the aid of numerous improvements in the treatment of infertility, over 80% of couples who dreamed of having children could now have children. Due to the fact that infertility has many negative effects on personal and social lives of young couples, many researchers have focused on the treatment of male and female reproductive system abnormalities with different types of stem cells, including embryonic stem cells, bone marrow mesenchymal stem cells (MSCs), and umbilical cord-derived MSCs. Also, design and formation of reproductive system organoids provide a fascinating window into disease modeling, drug screening, personalized therapy, and regeneration medicine. Utilizing these techniques to study, model and treat the infertility-related diseases has drawn attention of many scientists. This review explains different applications of stem cells in generating reproductive system organoids and stem cell-based therapies for male and female infertility related diseases treatment.

Role of bioactive xenobiotics towards reproductive potential of Odontotermes longignathus through in silico study: An amalgamation of ecoinformatics and ecotechnological insights of termite mounds from a tropical forest, India

The present research study has evaluated the roles of different naturally occurring compounds in termite mounds of Odontotermes longignathus (GenBank Id: MZ542727.1) which facilitate to promote higher population growth of termites and subsequent biodegradation. The study has also monitored the change in physicochemical parameters along with the trend of biodegradation of complex organic carbon-based compounds like lignin, polysaccharides etc. and nitrogenous compounds from two different types of termite mounds such as developing (T1) and developed (T2) mounds. The GC MS profiling of mound samples have revealed the occurrence of different humic acids like organic materials in both T1 and T2 mound samples. Both the termite mounds have demonstrated a high population density as T1 (23.67 ± 1.56) individuals and T2 (43.51 ± 2.36) individuals per 0.1 kg of mound materials. Such observations have prompted to undertake molecular docking experiments which revealed that different molecules interact at low binding affinity with hormone receptors involved in moulting, spermatogenesis and oogenesis of termite like Adamantane carboxylate (EcR: -7.6 Kcal/mol; BTB-KLHL10: -6.2 Kcal/mol; USP-LBD: -7.3 Kcal/mol; VgR: -6.8 Kcal/mol), Benzene dicarboxylic acid (EcR: -5.5 Kcal/mol; BTB-KLHL10: -5.1 Kcal/mol; USP-LBD: -5.4 Kcal/mol; VgR: -5.6 Kcal/mol), Hexadecanol (EcR: -6.0 Kcal/mol; BTB-KLHL10: -4.4 Kcal/mol; USP-LBD: -6.9 Kcal/mol; VgR: -6.0 Kcal/mol), oxirane (EcR: -5.3 Kcal/mol; BTB-KLHL10: -4.9 Kcal/mol; USP-LBD: -5.2 Kcal/mol; VgR: -5.3 Kcal/mol) and tocopherol (EcR: -8.0 Kcal/mol; BTB-KLHL10: -5.4 Kcal/mol; USP-LBD: -7.6 Kcal/mol; VgR: -7.0 Kcal/mol). Such spontaneous ligand binding phenomenon coupled with high population density of termites have established the significance of different bioactive xenobiotics in achieving high reproductive potential of termites which in turn facilitate the process of biodegradation and enhance the nutrient enrichment in the soils of tropical deciduous forest.

Copy number variants within AZF region of Y chromosome and their association with idiopathic male infertility in Serbian population

Results of numerous studies gave contradictory conclusions when analysing associations between copy number variants (CNVs) within the azoospermia factor (AZF) locus of the Y chromosome and idiopathic male infertility. The aim of this study was to identify the presence and possible association of CNVs in the AZF region of Y chromosome with idiopathic male infertility in the Serbian population. Using the multiplex ligation-dependent probe amplification technique, we were able to detect CNVs in 24 of 105 (22.86%) infertile men and in 11 of 112 (9.82%) fertile controls. The results of Fisher's exact test showed a statistically significant difference between cases and controls after merging g(reen)-r(ed)/g(reen)-r(ed) and b(lue)2/b(lue)3 partial deletions identified in the AZFc region (p = 0.024). At the same time, we observed a trend towards statistical significance for a deletion among gr/gr amplicons (p = 0.053). In addition to these, we identified a novel complex CNV involving inversion of r2/r3 amplicons, followed by b2/b3 duplication and b3/b4 deletion, respectively. Additional analyses on a larger study group would be necessary to draw meaningful conclusions about associations among CNVs that presented with higher frequency in the infertile men than the fertile controls.

The Role of Stem Cells and Their Derived Extracellular Vesicles in Restoring Female and Male Fertility

Infertility is a globally recognized issue caused by different reproductive disorders. To date, various therapeutic approaches to restore fertility have been attempted including etiology-specific medication, hormonal therapies, surgical excisions, and assisted reproductive technologies. Although these approaches produce results, however, fertility restoration is not achieved in all cases. Advances in using stem cell (SC) therapy hold a great promise for treating infertile patients due to their abilities to self-renew, differentiate, and produce different paracrine factors to regenerate the damaged or injured cells and replenish the affected germ cells. Furthermore, SCs secrete extracellular vesicles (EVs) containing biologically active molecules including nucleic acids, lipids, and proteins. EVs are involved in various physiological and pathological processes and show promising non-cellular therapeutic uses to combat infertility. Several studies have indicated that SCs and/or their derived EVs transplantation plays a crucial role in the regeneration of different segments of the reproductive system, oocyte production, and initiation of sperm production. However, available evidence triggers the need to testify the efficacy of SC transplantation or EVs injection in resolving the infertility issues of the human population. In this review, we highlight the recent literature covering the issues of infertility in females and males, with a special focus on the possible treatments by stem cells or their derived EVs.

Application of Stem Cell Therapy for Infertility

Infertility creates an immense impact on the psychosocial wellbeing of affected couples, leading to poor quality of life. Infertility is now considered to be a global health issue affecting approximately 15% of couples worldwide. It may arise from factors related to the male (30%), including varicocele, undescended testes, testicular cancer, and azoospermia; the female (30%), including premature ovarian failure and uterine disorders; or both partners (30%). With the recent advancement in assisted reproduction technology (ART), many affected couples (80%) could find a solution. However, a substantial number of couples cannot conceive even after ART. Stem cells are now increasingly being investigated as promising alternative therapeutics in translational research of regenerative medicine. Tremendous headway has been made to understand the biology and function of stem cells. Considering the minimum ethical concern and easily available abundant resources, extensive research is being conducted on induced pluripotent stem cells (iPSCs) and mesenchymal stem cells (MSC) for their potential application in reproductive medicine, especially in cases of infertility resulting from azoospermia and premature ovarian insufficiency. However, most of these investigations have been carried out in animal models. Evolutionary divergence observed in pluripotency among animals and humans requires caution when extrapolating the data obtained from murine models to safely apply them to clinical applications in humans. Hence, more clinical trials based on larger populations need to be carried out to investigate the relevance of stem cell therapy, including its safety and efficacy, in translational infertility medicine.

Impact of aluminium toxicity on vital human sperm parameters-Protective effects of silymarin

Aluminium is an environmental pollutant which induces oxidative stress, while silymarin is a potent antioxidant. This study was conducted to investigate the possible protective effects of silymarin on adverse effects of aluminium chloride on vital sperm parameters as well as its effects on oxidative stress markers in human spermatozoa. Human spermatozoa were divided into 5 groups as follows: (a) spermatozoa at 0 hr; (b) spermatozoa at 180 min (control); (c) spermatozoa treated with aluminium chloride; (d) spermatozoa treated with silymarin + aluminium chloride; and (e) spermatozoa treated with silymarin. The sperm samples were used to assess sperm vital parameters such as acrosome and plasma membrane integrity, viability, mitochondrial membrane potential (MMP) and motility as well as sperm malondialdehyde (MDA) level and the total antioxidant capacity. The percentage of acrosome and plasma membrane integrity, viability, MMP, motility and the total antioxidant capacity of spermatozoa treated with aluminium chloride significantly decreased compared with control group, while the level of MDA significantly increased compared with the control group. In the silymarin + aluminium chloride group, silymarin could significantly compensate the adverse effects of aluminium chloride on these parameters. Administration of silymarin alone significantly increased the percentage of acrosome and plasma membrane integrity, viability, motility and total antioxidant capacity, while significantly reduced MDA levels compared with the control group. Aluminium chloride by inducing oxidative stress exerts disastrous effects on the vital parameters of human spermatozoa and silymarin, as a potent antioxidant, could reverse the effects of aluminium chloride on these parameters.

Diagnosis and Treatment of Male Infertility-Related Fertilization Failure

Infertility affects approximately 15% of reproductive-aged couples worldwide, of which up to 30% of the cases are caused by male factors alone. The origin of male infertility is mostly attributed to sperm abnormalities, of which many are caused by genetic defects. The development of intracytoplasmic sperm injection (ICSI) has helped to circumvent most male infertility conditions. However, there is still a challenging group of infertile males whose sperm, although having normal sperm parameters, are unable to activate the oocyte, even after ICSI treatment. While ICSI generally allows fertilization rates of 70 to 80%, total fertilization failure (FF) still occurs in 1 to 3% of ICSI cycles. Phospholipase C zeta (PLCζ) has been demonstrated to be a critical sperm oocyte activating factor (SOAF) and the absence, reduced, or altered forms of PLCζ have been shown to cause male infertility-related FF. The purpose of this review is to (i) summarize the current knowledge on PLCζ as the critical sperm factor for successful fertilization, as well as to discuss the existence of alternative sperm-induced oocyte activation mechanisms, (ii) describe the diagnostic tests available to determine the cause of FF, and (iii) summarize the beneficial effect of assisted oocyte activation (AOA) to overcome FF.

Induced Pluripotent Stem Cells Derived From Two Idiopathic Azoospermia Patients Display Compromised Differentiation Potential for Primordial Germ Cell Fate

At present, the etiology of most non-obstructive azoospermia (NOA) remains unclear. In vitro generation of patient-specific induced pluripotent stem cells (iPSCs) is an effective approach for exploring the mechanisms of human disease. Here, we established iPSCs from two patients with idiopathic NOA and differentiated them into primordial germ cell-like cells (PGCLCs) in vitro. Compared with iPSCs derived from normal fertile men, the NOA patient-specific iPSCs show decreased efficiency of PGCLC formation in vitro. Particularly, the embryoids derived from NOA patient-specific iPSCs show defects in the expression of early primordial germ cell (PGC) genes. The transcriptome analysis reveals the expression patterns of key human PGC genes are generally similar in PGCLCs differentiated from all iPSC lines, and the differentially expressed genes were enriched with gene ontology (GO) of cell cycle and apoptosis regulation. Moreover, the PGCLCs derived from NOA patient-specific iPSCs might have initiated epigenetic reprogramming at a very early stage. Thus, the NOA patient-specific iPSCs exhibit poor response to germ cell induction in vitro, which may be related to the regulation of apoptotic process. These findings provide a foundation for future research on mechanism of male infertility.

Association of single-nucleotide polymorphisms in antioxidant genes and their gene-gene interactions with risk of male infertility in a Chinese population

The antioxidant defense system protects DNA from the damaging effects of oxidative stress and is hypothesized to be associated with an increased risk of male infertility. Polymorphisms in antioxidant genes and the gene-gene interactions associated with the antioxidant system may increase the potential risk of male infertility. In the present case-controlled study, the individual link between seven gene polymorphisms (NQO1 rs1800566, SOD2 rs4880, GSTM3 rs1571858, rs3814309, rs7483, GSTM5 rs11807 and GSTP1 rs1695) and the risk of male infertility was investigated. A total of 248 idiopathic infertility patients and 310 fertile controls were selected, and genotyping was performed using the Mass ARRAY platform. There were no significant associations between the seven polymorphisms and risk of male infertility. However, the analysis of gene-gene interactions showed a decreased risk of male infertility in GSTM3 rs3814309/NQO1 rs1800566 [CC x CT/TT; odds ratio (OR)=0.56, 95% confidence interval (CI)=0.34-0.92; P=0.022), and a significant association between a gene-gene interaction in GSTM3 rs1571858/NQO1 rs1800566 and azoospermia (AG/GG x CC; OR=3.84, 95% CI=1.25-11.81; P=0.019).

Expression and localization of Septin 14 gene and protein in infertile men testis

An increasing body of data implicates the Septin family in the pathology of several diseases, including male fertility. The objective of this study was to evaluate the gene and protein expression pattern of Septin 14 in the testis tissue of azoospermic men. In addition, Septin 14 localization was also assessed in the sperm. Testicular tissues were obtained from biopsies of non-obstrutive azoospermic men who underwent diagnostic testicular biopsy in Royan institute and were divided into two groups: TESE + with positive result in testicular sperm extraction (with hypospermatogenesis pathology) and TESE- with negative result (included patients with Sertoli cell only syndrome and maturation arrest pathologies). Total RNA and protein was extracted using trizol reagent. Septin 14 gene and protein expression level were assessed by real-time reverse transcription polymerase chain reaction (RT-PCR) and Western blot techniques, respectively. The localization of Septin 14 protein was also studied by Immunocytochemistry. The expression of Septin 14 was significantly lower (p < 0. 05) in TESE- group than TESE + in both mRNA and protein levels. The localization of Septin 14 protein was detected in the head to tail of normal sperms with high localization in front of the acrosome and the neck. This is a novel localization report on Septin 14 in sperm. Regarding the presence of this protein in the sperm acrosome and neck, it can be concluded that decreasing of Septin 14 protein expression may be associated with the pathogenesis of male infertility and therefore Septin 14 expression level maybe critical for human spermatogenesis.

Differentiation of neonate mouse spermatogonial stem cells on three-dimensional agar/polyvinyl alcohol nanofiber scaffold

Electrospun nanofiber matrices sufficiently mimic the structural morphology of natural extracellular matrix. In this study, we aimed to examine the effects of agar/polyvinyl alcohol nanofiber (PVA) scaffold on the proliferation efficiency and differentiation potential of neonate mouse spermatogonial stem cells (SCCs). Testicular cells were isolated from testes of 40 mouse pups and were seeded in: 1) 2D cell culture plates in the absence (2D/-GF) or presence (2D/+GF) of growth factors and 2) onto agar/PVA scaffold in the absence (3D/-GF) or presence (3D/+GF) of growth factors. The cells were subsequently cultured for 4 weeks. First 2 weeks were dedicated to proliferative phase, whereas the next 2 weeks emphasized the differentiation phase. The identity of the SCCs was investigated at different time-points by flow cytometry and quantitative reverse transcription PCR (qRT-PCR) analyses against the germ cell markers, including PLZF, Id-4, Gfrα-1, Tekt-1, and Sycp-3. After 2 weeks of culture, the 3D/+GF group showed the highest percentage of PLZF-positive cells among culture systems (P < 0.05). The expression levels of pre-meiotic markers (Id-4 and Gfrα-1) decreased significantly in all groups, particularly in 3D/+GF group after 28 days of culture. Additionally, the cells in the 3D/+GF group displayed the highest expression of meiotic (Sycp-3) and post-meiotic markers (Tekt-1) 14 days after differentiation induction. Seemingly, the combination of the agar/PVA scaffold and growth factor-supplemented medium synergistically increased the differentiation rate of mouse SSCs into meiotic and post-meiotic cells. Thus, agar/PVA nanofiber scaffolds may have the potential for applications in the restoration of infertility, especially in azoospermic males.

ABBREVIATIONS

2D: two dimentional; 3D: three dimentional; bFGF: basic fibroblast growth factor; BMP-4: bone morphogenetic protein 4; DMEM: Dulbecco's modified Eagle's medium; ECM: extracellular matrix; FCS: fetal calf serum; FTIR: Fourier-transform infrared spectroscopy; GDNF: glial cell line-derived neurotrophic factor; GF: growth factors; Gfrα-1, GDNF family co-receptor α1; Id-4, Inhibitor of DNA Binding 4; MTT: methylthiazoltetrazolium; PLZF: promyelocytic leukemia zinc finger; PVA: polyvinyl alcohol; qRT-PCR: quantitative reverse transcription PCR; RA: retinoic acid; SACS: soft agar culture system; SD: standard deviation; SEM: scanning electron microscope; SSCs: spermatogonial stem cells; Sycp-3, Synaptonemal complex protein 3; Tekt-1, Tektin 1.

Altered expression of some miRNAs and their target genes following mesenchymal stem cell treatment in busulfan-induced azoospermic rats

Studies have recently demonstrated that mesenchymal stem cells (MSCs) have therapeutic capabilities on many diseases and this effect is mainly mediated by miRNAs. However, the actual mechanism of MSCs paracrine effect on testis to improve male fertility is still elusive. Herein, we evaluated the altered expression of some spermatogenesis-related miRNAs and their target genes following transplantation of bone marrow (BM)-derived MSCs into testes of busulfan-induced azoospermic rats using real time PCR. Transplantation of MSCs improved fertility of azoospermic rats as revealed by enhanced serum levels of testosterone and estradiol, and upregulated expression of germ cell‑specific genes. Azo rats injected with MSCs also exhibited a significant downregulated expression of miRNA-19b, miRNA-100, miRNA-141, miRNA‑146a, miRNA-429, and let‑7a and a significant upregulated expression of miRNA-21, miRNA-34b, miRNA-34c, miRNA-122, miRNA-449a, miRNA-449b, and miRNA-449c in the testis as compared to Azo rats injected with phosphate buffer saline. Transplantation of MSCs was also accompanied with restoration of the disrupted expression of Ccnd1, E2F1, Myc, and PLCXD3 (target genes for miRNA-34 and miRNA‑449 clusters) and ERα and AKT1 (target genes for miRNA-100 and let‑7a) to level comparable to that of the fertile group. Upon these data, we infer that BM-MSCs can improve fertility of azoospermic rats and this effect was followed by altered expression of some spermatogenesis-related miRNAs and their target genes. These findings provide MSCs as a promising and effective cell-based therapeutic method for azoospermic patients, but further investigations are required before clinical application.

Restore natural fertility of Kitw/Kitwv mouse with nonobstructive azoospermia through gene editing on SSCs mediated by CRISPR-Cas9

Background

Male infertility is a serious social problem in modern society. Nonobstructive azoospermia (NOA) caused by germ cell gene defects is an important reason for male infertility, but effective clinical treatment for this disease has not been established.

Methods

We choose Kit^w/Kit^wv mouse as a research model and try to develop a new treatment strategy and “cure” its infertility. Mutant spermatogonial stem cells (SSCs) were isolated from one single unilateral testis of a 14-day-old Kit^w/Kit^wv mouse and propagated in vitro. The C to T point mutation on Kit^wv site of these SSCs was corrected through CRISPR-Cas9-mediated homology-directed repair (HDR) in vitro. Then, the repaired SSCs were screened out, proliferated, and transplanted into the remaining testis, and complete spermatogenesis was established in the recipient testis.

Results

Healthy offsprings with wild type Kit gene or Kit^w mutation were obtained through natural mating 4 months after SSC transplantation.

Conclusion

In this study, we established an effective new treatment strategy for NOA caused by germ cell gene defects through a combination of SSC isolation, CRISPR-Cas9-mediated gene editing, and SSC transplantation, which brought hope for these NOA patients to restore their natural fertility.

Multiple signaling pathways in Sertoli cells: recent findings in spermatogenesis

The functions of Sertoli cells in spermatogenesis have attracted much more attention recently. Normal spermatogenesis depends on Sertoli cells, mainly due to their influence on nutrient supply, maintenance of cell junctions, and support for germ cells' mitosis and meiosis. Accumulating evidence in the past decade has highlighted the dominant functions of the MAPK, AMPK, and TGF-β/Smad signaling pathways during spermatogenesis. Among these pathways, the MAPK signaling pathway regulates dynamics of tight junctions and adherens junctions, proliferation and meiosis of germ cells, proliferation and lactate production of Sertoli cells; the AMPK and the TGF-β/Smad signaling pathways both affect dynamics of tight junctions and adherens junctions, as well as the proliferation of Sertoli cells. The AMPK signaling pathway also regulates lactate supply. These signaling pathways combine to form a complex regulatory network for spermatogenesis. In testicular tumors or infertile patients, the activities of these signaling pathways in Sertoli cells are abnormal. Clarifying the mechanisms of signaling pathways in Sertoli cells on spermatogenesis provides new insights into the physiological functions of Sertoli cells in male reproduction, and also serves as a pre-requisite to identify potential therapeutic targets in abnormal spermatogenesis including testicular tumor and male infertility.

Transplantation of mouse iPSCs into testis of azoospermic mouse model: in vivo and in vitro study

This study aimed to induce spermatogenesis in azoospermic testis through induced pluripotent stem cells (iPSCs) derived spermatogonial stem cell-like cells (SSCLCs) after iPSCs in vivo and in vitro transplantation and three-dimensional organ culture. DiI-labelled mouse iPSCs were transplanted to azoospermic testis mouse model (pretreated by busulfan 40 mg/kg). This study was designed based on two experimental groups. In experimental group 1(in vivo) labelled iPSCs were transplanted to azoospermic host testis. In experimental group 2 (in vitro) after cell transplantation, fragments of host testes were set as 3D organ culture and testis without cells transplantation served as the control group by the same method. The samples were evaluated by tracing DiI, cell homing, immunohistochemistry, and quantitative RT PCR assays. 2 weeks after iPSCs transplantation, the molecular assessment showed that Plzf, Thy1, Vasa and Gfra1 expression were increased significantly (p ≤ .05) in host testis and labelled iPSCs co-localized by the Plzf and Thy1 markers expression in the base of seminiferous tubules. These findings suggest the ability of iPSCs to achieve homing in the testis niche and indicate the critical inductive role of microenvironment signals in the differentiation of iPSCs to spermatogonial stem cell-like cells.

Human induced pluripotent stem cells and male infertility: an overview of current progress and perspectives

Recently, significant progress has been made in ART for the treatment of male infertility. However, current ART has failed to help infertile patients with non-obstructive azoospermia, unless donor sperm is used. In fact, most couples wish to have their own genetically related child. Human induced pluripotent stem cells (hiPSCs) can be generated from patients’ somatic cells and in vitro derivation of functional germ cells from patient-specific iPSCs may provide new therapeutic strategies for infertile couples. The overall developmental dynamics of human primordial germ cells are similar to that in mice, but accumulating evidence suggests that there are crucial differences between human and mouse PGC specification. Unlike mouse iPSCs (miPSCs) in naive state, hiPSCs exhibit a primed pluripotency which possess less potential for the germ cell fate. Based on research in mice, male germ cells at different stages have been derived from hiPSCs with different protocols, including spontaneous differentiation, overexpression of germ cell regulators, addition of cytokines, co-culture with gonadal cells in vitro and xeno-transplantation. The aim of this review is to summarize the current advances in derivation of male germ cells from hiPSCs and raise the perspectives of hiPSCs in medical application for male infertility, as well as in basic research for male germ cell development.

Mesenchymal Stem Cells (MSCs) Therapy for Recovery of Fertility: a Systematic Review

In recent years, the mesenchymal stem cells (MSCs) have provided the new opportunities to treat different disorders including infertility. Different studies have suggested that the MSCs have ability to differentiate into germ-like cells under specific induction conditions as well as transplantation to gonadal tissues. The aim of this systematic review was to evaluate the results obtained from different studies on MSCs therapy for promoting fertility. This search was done in PubMed and Science Direct databases using key words MSCs, infertility, therapy, germ cell, azoospermia, ovarian failure and mesenchymal stem cell. Among the more than 11,400 papers, 53 studies were considered eligible for more evaluations. The obtained results indicated that the most studies were performed on MSCs derived from bone marrow and umbilical cord as compared with the other types of MSCs. Different evaluations on animal models as well as in vitro studies supported from their role in the recovery of spermatogenesis and folliculogenesis. Although the data obtained from this systematic review are promising, but the further studies need to assess the efficiency and safety of transplantation of these cells in fertility recovery.

Proteomic changes during adult stage in pre-optic, hypothalamus, hippocampus and pituitary regions of female rat brain following neonatal exposure to estradiol-17β

Although neonatal exposure to estrogen or estrogenic compounds results in irreversible changes in the brain function and reproductive abnormalities during adulthood but the underlying mechanisms are still largely unknown. The present study has attempted to compare the protein profiles of sexually dimorphic brain regions of adult female rats which were exposed to estradiol- 17β during neonatal period. The total proteins extracted from pre-optic area (POA), hypothalamus, hippocampus and pituitary of control and neonatally E2 treated female rats was subjected to 2D-SDS-PAGE and differentially expressed proteins were identified by MALDI TOF/TOF-MS. Our results revealed that a total of 21 protein spots which were identified as differentially expressed in all the four regions analyzed; the differential expression was further validated by RT-PCR and western blotting. The differentially expressed proteins such as 14-3-3 zeta/delta (POA), LMNA (hippocampus), Axin2 (hypothalamus), Syntaxin-7 (hippocampus), prolactin and somatotropin (pituitary) which have very important functions in the process of neuronal differentiation, migration, axon outgrowth, formation of dendritic spine density and synaptic plasticity and memory have not been previously reported in association with neonatal estrogen exposure. The affected brain functions are very important for the establishment of sex specific brain morphology and behavior. Our results suggest that the differentially expressed proteins may play an important role in irreversible changes in the brain function as well as reproductive abnormalities observed in the female rats during adulthood.

Should 45,X/46,XY boys with no or mild anomaly of external genitalia be investigated and followed up?

OBJECTIVE

Few studies of patients with a 45,X/46,XY mosaicism have considered those with normal male phenotype. The purpose of this study was to evaluate the clinical outcome of 45,X/46,XY boys born with normal or minor abnormalities of external genitalia, notably in terms of growth and pubertal development.

METHODS

Retrospective longitudinal study of 40 patients followed between 1982 and 2017 in France.

RESULTS

Twenty patients had a prenatal diagnosis, whereas 20 patients had a postnatal diagnosis, mainly for short stature. Most patients had stunted growth, with abnormal growth spurt during puberty and a mean adult height of 158 ± 7.6 cm, i.e. -2.3 DS with correction for target height. Seventy percent of patients presented Turner-like syndrome features including cardiac (6/23 patients investigated) and renal malformations (3/19 patients investigated). Twenty-two patients had minor abnormalities of external genitalia. One patient developed a testicular embryonic carcinoma, suggesting evidence of partial gonadal dysgenesis. Moreover, puberty occurred spontaneously in 93% of patients but 71% (n = 5) of those evaluated at the end of puberty presented signs of declined Sertoli cell function (low inhibin B levels and increased FSH levels).

CONCLUSION

This study emphasizes the need to identify and follow-up 45,X/46,XY patients born with normal male phenotype until adulthood, as they present similar prognosis than those born with severe genital anomalies. Currently, most patients are diagnosed in adulthood with azoospermia, consistent with our observations of decreased testicular function at the end of puberty. Early management of these patients may lead to fertility preservation strategies.

Spermatogenesis after Transplantation of Adipose Tissue-Derived Stem Cells in Azoospermic Guinea Pigs: A Histological and Histomorphometric Study

Background:

The purpose of this research was to determine histomorphometric changes in busulfan-induced azoospermia after transplantation of Adipose Tissue-Derived Stem Cells (AdSCs) in guinea pig. AdSCs were isolated from adipose tissue around the testes of guinea pigs and characterized for mesenchymal properties.

Materials and Methods:

Guinea pigs were allocated into three groups, including the control group without any intervention. To induce azoospermia, groups 2 and 3 received a dose of 40 mg/kg of busulfan with 21 days interval. Group 3 received 1×106 AdSCs in their seminiferous tubules of left testes, 35 days following last busulfan injection, while right testis in the group was considered for comparison as controls. Sixty days following transplantation of cell, histomorphometric and histopathologic changes of the experiments were assessed.

Results:

After AdSCs’ transplantation, normal spermatogenesis appearance was noticed compared to busulfan-induced azoospermia and AdSCs recovered spermatogenesis, and our findings can be added to the literature in treating azoospermic infertilities.

Conclusion:

The transplanted AdSCs could induce production of germinal cells using testicular seminiferous tubules and were an effective source in treating azoospermia

A multi-scale analysis of bull sperm methylome revealed both species peculiarities and conserved tissue-specific features

BACKGROUND

Spermatozoa have a remarkable epigenome in line with their degree of specialization, their unique nature and different requirements for successful fertilization. Accordingly, perturbations in the establishment of DNA methylation patterns during male germ cell differentiation have been associated with infertility in several species. While bull semen is widely used in artificial insemination, the literature describing DNA methylation in bull spermatozoa is still scarce. The purpose of this study was therefore to characterize the bull sperm methylome relative to both bovine somatic cells and the sperm of other mammals through a multiscale analysis.

RESULTS

The quantification of DNA methylation at CCGG sites using luminometric methylation assay (LUMA) highlighted the undermethylation of bull sperm compared to the sperm of rams, stallions, mice, goats and men. Total blood cells displayed a similarly high level of methylation in bulls and rams, suggesting that undermethylation of the bovine genome was specific to sperm. Annotation of CCGG sites in different species revealed no striking bias in the distribution of genome features targeted by LUMA that could explain undermethylation of bull sperm. To map DNA methylation at a genome-wide scale, bull sperm was compared with bovine liver, fibroblasts and monocytes using reduced representation bisulfite sequencing (RRBS) and immunoprecipitation of methylated DNA followed by microarray hybridization (MeDIP-chip). These two methods exhibited differences in terms of genome coverage, and consistently, two independent sets of sequences differentially methylated in sperm and somatic cells were identified for RRBS and MeDIP-chip. Remarkably, in the two sets most of the differentially methylated sequences were hypomethylated in sperm. In agreement with previous studies in other species, the sequences that were specifically hypomethylated in bull sperm targeted processes relevant to the germline differentiation program (piRNA metabolism, meiosis, spermatogenesis) and sperm functions (cell adhesion, fertilization), as well as satellites and rDNA repeats.

CONCLUSIONS

These results highlight the undermethylation of bull spermatozoa when compared with both bovine somatic cells and the sperm of other mammals, and raise questions regarding the dynamics of DNA methylation in bovine male germline. Whether sperm undermethylation has potential interactions with structural variation in the cattle genome may deserve further attention.

A novel TEX11 mutation induces azoospermia: a case report of infertile brothers and literature review

Background

Testis-expressed gene 11 (TEX11) is an X-linked gene and essential for meiotic recombination and chromosomal synapsis. TEX11 deficiency causes meiotic arrest and male infertility, and many TEX11 mutations have been found in azoospermic and infertile men.

Case presentation

This study reported one novel TEX11 mutation (2653G → T, in exon 29, GenBank accession number, NM_031276) in two brothers with azoospermia. This mutation was firstly screened out by whole-exome sequencing (WES) and further verified by amplifying and sequencing the specific exon 29. Surprisingly, the same exonic missense mutation (W856C) was observed in two brothers but not in their mother. Histological analysis of testicular biopsy from both brothers revealed meiotic arrest and no post-meiotic round spermatids and mature spermatozoa were observed in the seminiferous tubules. TEX11 expression was observed strongly in spermatogonia and weakly in spermatocytes, but not in Sertoli cells and interstitial cells.

Conclusions

We identified one novel TEX11 mutation in two brothers and summarized the literature regarding TEX11 mutations and male infertility. This study and previous literature indicate that TEX11 mutations are closely associated with male infertility, especially azoospermia, although auxiliary clinical analyses are needed to figure out the causes of male infertility.

Association between two common transitions of H2BFWT gene and male infertility: a case-control, meta, and structural analysis

H2BFWT is one of the testis-specific histones that plays a fundamental role in spermatogenesis, and single nucleotide polymorphisms (SNPs) in this gene may result in male infertility. This study aimed to investigate the association between -9C>T and 368A>G transitions of H2BFWT gene and male infertility through a case-control, meta-analysis, and a bioinformatics approach. In this case-control study, 490 subjects including 240 idiopathic infertile men and 250 healthy controls were included. The -9C>T and 368A>G SNPs genotyping were performed by a PCR-RFLP method. To find eligible studies for meta-analysis, we searched valid scientific databases. The odds ratios with 95% confidence intervals were estimated to find the strength of these associations. Furthermore, the influences of two common transitions on the molecular features of H2BFWT were assessed by in silico tools. Our case-control data revealed that -9C>T is not associated with male infertility. But, there was a significant association between 368A>G and male infertility. In the meta-analysis, five eligible studies were included. Our data revealed significant associations between -9C>T, 368A>G, and male infertility in overall and stratified analyses. Moreover, structural analysis showed that 368A>G could affect the protein structure (SNAP prediction: non-neutral, score: 42, expected accuracy: 71%; SIFT prediction: deleterious, score: -2.55), while -9C>T may affect the binding nucleotide in the promoter region. Based on these findings, two aforementioned polymorphisms were associated with increased risk of male infertility. However, studies with larger sample size and different ethnicities are needed to obtain more accurate conclusions.

Next-generation sequencing for patients with non-obstructive azoospermia: implications for significant roles of monogenic/oligogenic mutations

Azoospermia affects up to 1% of adult men. Non-obstructive azoospermia is a multifactorial disorder whose molecular basis remains largely unknown. To date, mutations in several genes and multiple submicroscopic copy-number variations (CNVs) have been identified in patients with non-obstructive azoospermia. The aim of this study was to clarify the contribution of nucleotide substitutions in known causative genes and submicroscopic CNVs in the genome to the development of non-obstructive azoospermia. To this end, we conducted sequence analysis of 25 known disease-associated genes using next-generation sequencing and genome-wide copy-number analysis using array-based comparative genomic hybridization. We studied 40 Japanese patients with idiopathic non-obstructive azoospermia. Functional significance of molecular alterations was assessed by in silico analyses. As a result, we identified four putative pathogenic mutations, four rare polymorphisms possibly associated with disease risk, and four probable neutral variants in 10 patients. These sequence alterations included a heterozygous splice site mutation in SOHLH1 and a hemizygous missense substitution in TEX11, which have been reported as causes of non-obstructive azoospermia. Copy-number analysis detected five X chromosomal or autosomal CNVs of unknown clinical significance, in addition to one known pathogenic Y chromosomal microduplication. Five patients carried multiple molecular alterations. The results indicate that monogenic and oligogenic mutations, including those in SOHLH1 and TEX11, account for more than 10% of cases of idiopathic non-obstructive azoospermia. Furthermore, this study suggests possible contributions of substitutions in various genes as well as submicroscopic CNVs on the X chromosome and autosomes to non-obstructive azoospermia, which require further validation.

The rs1127354 Polymorphism in ITPA Is Associated with Susceptibility to Infertility

Objective

Infertility is a common human disorder which is defined as the failure to conceive for a period of 12 months without contraception. Many studies have shown that the outcome of fertility could be affected by DNA damage. We attempted to examine the association of two SNPs (rs1127354 and rs7270101) in ITPA, a gene encoding a key factor in the repair system, with susceptibility to infertility.

Materials and Methods

This was a case-control study of individuals with established infertility. Blood samples were obtained from 164 infertile patients and 180 ethnically matched fertile controls. Total genomic DNA were extracted from whole blood using the standard salting out method, and stored at -20˚C. Genotyping were based on mismatch polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method in which PCR products were digested with the XmnI restriction enzyme and run on a 12% polyacrylamide gel.

Results

All genotype frequencies in the control group were in Hardy-Weinberg equilibrium. A significant association (in allelic, recessive and dominant genotypic models) was observed between infertile patients and healthy controls based on rs1127354 (P=0.0001), however, no significant association was detected for rs7270101. Also, gender stratification and analysis of different genotype models did not lead to a significant association for this single- nucleotide polymorphis (SNP).

Conclusion

ITPA is likely to be a genetic determinant for decreased fertility. To the best of our knowledge, this is the first report demonstrating this association, however, given the small sample size and other limitations, genotyping of this SNP is recommended to be carried out in different populations with more samples.

Specialize and Divide (Twice): Functions of Three Aurora Kinase Homologs in Mammalian Oocyte Meiotic Maturation

The aurora kinases (AURKs) comprise an evolutionarily conserved family of serine/threonine kinases involved in mitosis and meiosis. While most mitotic cells express two AURK isoforms (AURKA and AURKB), mammalian germ cells also express a third, AURKC. Although much is known about the functions of the kinases in mitosis, less is known about how the three isoforms function to coordinate meiosis. This review is aimed at describing what is known about the three isoforms in female meiosis, the similarities and differences between kinase functions, and speculates as to why mammalian germ cells require expression of three AURKs instead of two.

Human male infertility and its genetic causes

Background

Infertility affects about 15% of couples who wish to have children and half of these cases are associated with male factors. Genetic causes of azoospermia include chromosomal abnormalities, Y chromosome microdeletions, and specific mutations/deletions of several Y chromosome genes. Many researchers have analyzed genes in the AZF region on the Y chromosome; however, in 2003 the SYCP3 gene on chromosome 12 (12q23) was identified as causing azoospermia by meiotic arrest through a point mutation.

Methods

We mainly describe the SYCP3 and PLK4 genes that we have studied in our laboratory, and add comments on other genes associated with human male infertility.

Results

Up to now, The 17 genes causing male infertility by their mutation have been reported in human.

Conclusions

Infertility caused by nonobstructive azoospermia (NOA) is very important in the field of assisted reproductive technology. Even with the aid of chromosomal analysis, ultrasonography of the testis, and detailed endocrinology, only MD‐TESE can confirm the presence of immature spermatozoa in the testes. We strongly hope that these studies help clinics avoid ineffective MD‐TESE procedures.

A novel functional variant in Wilms' Tumor 1 (WT1) is associated with idiopathic non-obstructive azoospermia

Idiopathic nonobstructive azoospermia (INOA) is one of the most severe forms of male infertility, yet its pathophysiology remains unclear. WT1 (Wilms' tumor 1) regulates the polarity of Sertoli cells, thereby playing a critical, indirect role in spermatogenesis. Here, we evaluated WT1 gene variation associates with INOA by assessing its promoter and coding regions in 200 patients diagnosed with INOA and 200 proven-fertile men. Three novel variants in the WT1 coding region were detected only in INOA patients, including two synonymous variants and one missense variant, p.Phe435Leu (p.F435L), which was predicted to be deleterious to protein function. The results of dual luciferase reporter showed that the WT1 p.F435L variant decreases transcription of COL4A1 and WNT4 promoters through a dominant-negative effect. Furthermore, chromatin immunoprecipitation assays revealed that COL4A1 and WNT4 promoter is directly bound by wild-type WT1 protein, but not the p.F435L WT1 variant. Thus, we identified a novel functional variant of WT1 functionally associated with INOA. Mol. Reprod. Dev. 84: 222-228, 2017. © 2017 Wiley Periodicals, Inc.

Single-nucleotide polymorphisms in the human RAD21L gene may be a genetic risk factor for Japanese patients with azoospermia caused by meiotic arrest and Sertoli cell-only syndrome

Genetic mechanisms are implicated in some cases of male infertility. Recently, it was demonstrated that male mice lacking the gene for RAD21L exhibited azoospermia caused by meiotic arrest. Mouse RAD21L is a functionally relevant meiotic α-kleisin that is essential for male fertility. Therefore, we hypothesized that RAD21L mutations or polymorphisms may be associated with male infertility, especially azoospermia secondary to meiotic arrest. To determine if RAD21L defects are associated with azoospermia in groups of patients with meiotic arrest, we performed direct sequencing of the RAD21L coding regions in 38 Japanese patients with meiotic arrest and in 200 normal controls. Three coding single-nucleotide polymorphisms (SNP1-SNP3) were detected in the meiotic arrest patient group. Sertoli cell-only syndrome is considered a common cause of non-obstructive azoospermia. For comparison, the RAD21L coding regions in which SNP1-SNP3 were detected were sequenced in 140 patients with Sertoli cell-only syndrome. Statistical analyses were used to compare the two groups of patients with the control group. Genotype and allele frequencies of SNP2 and SNP3 were notably higher in the two patient groups compared with the control group (Bonferroni adjusted p value <0.016). These results suggest a critical role for RAD21L in human spermatogenesis.

A network-based method for the identification of putative genes related to infertility

BACKGROUND

Infertility has become one of the major health problems worldwide, with its incidence having risen markedly in recent decades. There is an urgent need to investigate the pathological mechanisms behind infertility and to design effective treatments. However, this is made difficult by the fact that various biological factors have been identified to be related to infertility, including genetic factors.

METHODS

A network-based method was established to identify new genes potentially related to infertility. A network constructed using human protein-protein interactions based on previously validated infertility-related genes enabled the identification of some novel candidate genes. These genes were then filtered by a permutation test and their functional and structural associations with infertility-related genes.

RESULTS

Our method identified 23 novel genes, which have strong functional and structural associations with previously validated infertility-related genes.

CONCLUSIONS

Substantial evidence indicates that the identified genes are strongly related to dysfunction of the four main biological processes of fertility: reproductive development and physiology, gametogenesis, meiosis and recombination, and hormone regulation.

GENERAL SIGNIFICANCE

The newly discovered genes may provide new directions for investigating infertility. This article is part of a Special Issue entitled "System Genetics" Guest Editor: Dr. Yudong Cai and Dr. Tao Huang.

Male infertility: an obstacle to sexuality?

Interactions between infertility and sexuality are numerous and complex. Infertile men may suffer from sexual dysfunction (SD) when undergoing an assisted reproductive technology programme. We undertook a review both in French and English of the available data on male SD when being diagnosed with a fertility problem with a specific focus on azoospermic men. The review was performed over a 30-year time period using PubMed/Medline. The sexual concerns and needs of infertile/sterile men for whom potential parenting can be compromised were evaluated. When diagnosed with infertility, men usually go through a crisis that can have a deleterious effect on their sexuality with sometimes a feeling of sexual inadequacy. Infertile men will feel stigmatized because they are perceived as being deficient in a specific component of their masculinity. Hence, subsequent SD may occur that can impact the couple sexuality and the infertility management. However, little is known on how the announcement of azoospermia may affect male on a sexual and psychological point of view. The present review suggests that a global management through a healthcare network (biologist, andrologist, sexologist and psychologist) is required which will allow to consider infertility and its subsequent sexual disorders as a whole and not as dichotomized issues.

Is there a role for DAZL in human female fertility?

The RNA binding protein deleted in azoospermia-like (Dazl) is a key determinant of germ cell maturation and entry into meiosis in rodents and other animal species. Although the complex phenotype of Dazl deficiency in both sexes, with defects at multiple stages of germ cell development and during meiosis, demonstrates its obligate significance in fertility in animal models, its involvement in human fertility is less clear. As an RNA binding protein, identification of the in vivo mRNA targets of DAZL is necessary to understand its influence. Thus far, only a small number of Dazl targets have been identified, which typically have pivotal roles in germ cell development and meiotic progression. However, it is likely that there are a number of additional germ cell and meiosis-relevant transcripts whose translation is affected in the absence of Dazl. Efforts to identify these RNA targets have mainly been focused on spermatogenesis, and restricted to mouse. In women, prophase I occurs in fetal life and it is during this period that the ovarian follicle pool is established, thus factors that have a role in determining the quality and quantity of the ovarian reserve may have significant impact on reproductive outcomes later in adult life. Here, we suggest that DAZL may be one such factor, and there is a need for greater understanding of the role of DAZL in human oogenesis and its contribution to lifelong female fertility.