Originating but free from chromosomal DNA, extrachromosomal circular DNAs (eccDNAs) are organized in circular form and have long been found in unicellular and multicellular eukaryotes. Their biogenesis and function are poorly understood as they are characterized by sequence homology with linear DNA, for which few detection methods are available. Recent advances in high-throughput sequencing technologies have revealed that eccDNAs play crucial roles in tumor formation, evolution, and drug resistance as well as aging, genomic diversity, and other biological processes, bringing it back to the research hotspot. Several mechanisms of eccDNA formation have been proposed, including the breakage-fusion-bridge (BFB) and translocation-deletion-amplification models. Gynecologic tumors and disorders of embryonic and fetal development are major threats to human reproductive health. The roles of eccDNAs in these pathological processes have been partially elucidated since the first discovery of eccDNA in pig sperm and the double minutes in ovarian cancer ascites. The present review summarized the research history, biogenesis, and currently available detection and analytical methods for eccDNAs and clarified their functions in gynecologic tumors and reproduction. We also proposed the application of eccDNAs as drug targets and liquid biopsy markers for prenatal diagnosis and the early detection, prognosis, and treatment of gynecologic tumors. This review lays theoretical foundations for future investigations into the complex regulatory networks of eccDNAs in vital physiological and pathological processes.
Male ; Female ; Animals ; Humans ; Swine ; DNA, Circular/genetics* ; Genital Neoplasms, Female ; Semen ; DNA ; Reproduction

Humans ; Male ; Semen ; Sperm Motility ; Mediation Analysis ; East Asian People ; Microcystins/toxicity* ; Spermatozoa ; Sperm Count ; Infertility, Male

Male diabetic individuals present a marked impairment in fertility; however, knowledge regarding the pathogenic mechanisms and therapeutic strategies is unsatisfactory. The new hypoglycemic drug dapagliflozin has shown certain benefits, such as decreasing the risk of cardiovascular and renal events in patients with diabetes. Even so, until now, the effects and underlying mechanisms of dapagliflozin on diabetic male infertility have awaited clarification. Here, we found that dapagliflozin lowered blood glucose levels, alleviated seminiferous tubule destruction, and increased sperm concentrations and motility in leptin receptor-deficient diabetic db/db mice. Moreover, the glucagon-like peptide-1 receptor (GLP-1R) antagonist exendin (9-39) had no effect on glucose levels but reversed the protective effects of dapagliflozin on testicular structure and sperm quality in db/db mice. We also found that dapagliflozin inhibited the testicular apoptotic process by upregulating the expression of the antiapoptotic protein B-cell lymphoma 2 (BCL2) and X-linked inhibitor of apoptosis protein (XIAP) and inhibiting oxidative stress by enhancing the antioxidant status, including total antioxidant capacity, total superoxide dismutase (SOD) activity, and glutathione peroxidase (GPx) activity, as well as decreasing the level of 4-hydroxynonenal (4-HNE). Exendin (9-39) administration partially reversed these effects. Furthermore, dapagliflozin upregulated the glucagon-like peptide-1 (GLP-1) level in plasma and GLP-1R expression by promoting AKT8 virus oncogene cellular homolog (Akt) phosphorylation in testicular tissue. Exendin (9-39) partially inhibited Akt phosphorylation. These results suggest that dapagliflozin protects against diabetes-induced spermatogenic dysfunction via activation of the GLP-1R/phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway. Our results indicate the potential effects of dapagliflozin against diabetes-induced spermatogenic dysfunction.
Mice ; Animals ; Male ; Proto-Oncogene Proteins c-akt/metabolism* ; Antioxidants ; Phosphatidylinositol 3-Kinases/metabolism* ; Semen/metabolism* ; Diabetes Mellitus

Coronavirus disease 2019 (COVID-19) has yet to be proven to alter male reproductive function, particularly in the majority of mild/asymptomatic patients. The purpose of this study was to explore whether mild/asymptomatic COVID-19 affects semen quality and sex-related hormone levels. To find suitable comparative studies, a systematic review and meta-analysis was done up to January 22, 2022, by using multiple databases (Web of Science, PubMed, and Embase). Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used to identify and choose the studies. Meta-analysis was used to examine the semen parameters and sex-related hormones of mild/asymptomatic COVID-19 patients before and after infection. The effects of semen collection time, fever, and intensity of verification on semen following infection were also investigated. A total of 13 studies (n = 770) were included in the analysis, including three case-control studies, six pre-post studies, and four single-arm studies. A meta-analysis of five pre-post studies showed that after infection with COVID-19, sperm concentration (I² = 0; P = 0.003), total sperm count (I² = 46.3%; P = 0.043), progressive motility (I² = 50.0%; P < 0.001), total sperm motility (I² = 76.1%; P = 0.047), and normal sperm morphology (I² = 0; P = 0.001) decreased. Simultaneously, a systematic review of 13 studies found a significant relationship between semen collection time after infection, inflammation severity, and semen parameter values, with fever having only bearing on semen concentration. Furthermore, there was no significant difference in sex-related hormone levels before and after infection in mild/asymptomatic patients. Mild/asymptomatic COVID-19 infection had a significant effect on semen quality in the short term. It is recommended to avoid initiating a pregnancy during this period of time.
Pregnancy ; Female ; Humans ; Male ; Semen Analysis ; Semen ; Infertility, Male ; Sperm Motility ; COVID-19 ; Sperm Count ; Spermatozoa ; Testosterone ; Gonadal Steroid Hormones

Bisphenol A is a common environmental factor and endocrine disruptor that exerts a negative impact on male reproductive ability. By exploring bisphenol A-induced testicular cell death using the Institute of Cancer Research (ICR) mouse model, we found that a ferroptosis phenomenon may exist. Mice were divided into six groups and administered different doses of bisphenol A via intragastric gavage once daily for 45 consecutive days. Serum was then collected to determine the levels of superoxide dismutase and malondialdehyde. Epididymal sperm was also collected for semen analysis, and testicular tissue was collected for ferritin content determination, electron microscope observation of mitochondrial morphology, immunohistochemistry, real-time quantitative polymerase chain reaction, and western blot analysis. Exposure to bisphenol A was found to decrease sperm quality and cause oxidative damage, iron accumulation, and mitochondrial damage in the testes of mice. In addition, bisphenol A was confirmed to affect the expression of the ferroptosis-related genes, glutathione peroxidase 4 (GPX4), ferritin heavy chain 1 (FTH1), cyclooxygenase 2 (COX2), and acyl-CoA synthetase 4 (ACSL4) in mouse testicular tissues. Accordingly, we speculate that bisphenol A induces oxidative stress, which leads to the ferroptosis of testicular cells. Overall, the inhibition of ferroptosis may be a potential strategy to reduce male reproductive toxicity caused by bisphenol A.
Male ; Mice ; Animals ; Testis/metabolism* ; Ferroptosis ; Semen ; Oxidative Stress

Teratozoospermia is a rare disease associated with male infertility. Several recurrent genetic mutations have been reported to be associated with abnormal sperm morphology, but the genetic basis of tapered-head sperm is not well understood. In this study, whole-exome sequencing (WES) identified a homozygous WD repeat domain 12 (WDR12; p.Ser162Ala/c.484T>G) variant in an infertile patient with tapered-head spermatozoa from a consanguineous Chinese family. Bioinformatic analysis predicted this mutation to be a pathogenic variant. To verify the effect of this variant, we analyzed WDR12 protein expression in spermatozoa of the patient and a control individual, as well as in the 293T cell line, by Western blot analysis, and found that WDR12 expression was significantly downregulated. To understand the role of normal WDR12, we evaluated its mRNA and protein expression in mice at different ages. We observed that WDR12 expression was increased in pachytene spermatocytes, with intense staining visible in round spermatid nuclei. Based on these results, the data suggest that the rare biallelic pathogenic missense variant (p.Ser162Ala/c.484T>G) in the WDR12 gene is associated with tapered-head spermatozoa. In addition, after intracytoplasmic sperm injection (ICSI), a successful pregnancy was achieved. This finding indicates that infertility associated with this WDR12 homozygous mutation can be overcome by ICSI. The present results may provide novel insights into understanding the molecular mechanisms of male infertility.
Humans ; Pregnancy ; Female ; Male ; Animals ; Mice ; Teratozoospermia/pathology* ; Semen/metabolism* ; Infertility, Male/metabolism* ; Spermatozoa/metabolism* ; Mutation ; RNA-Binding Proteins/metabolism* ; Cell Cycle Proteins/genetics*

The process of semen collection plays a key role in the quality of semen specimens. However, the association between semen collection time and semen quality is still unclear. In this study, ejaculates by masturbation from 746 subfertile men or healthy men who underwent semen analysis were examined. The median (interquartile range) semen collection time for all participants was 7.0 (5.0-11.0) min, and the median time taken for semen collection was lower in healthy men than that in subfertile men (6.0 min vs 7.0 min). An increase in the time required to produce semen samples was associated with poorer semen quality. Among those undergoing assisted reproductive technology (ART), the miscarriage rate was positively correlated with the semen collection time. After adjusting for confounders, the highest quartile (Q4) of collection time was negatively associated with semen volume and sperm concentration. A longer time to produce semen samples (Q3 and Q4) was negatively correlated with progressive and total sperm motility. In addition, there was a significant negative linear association between the semen collection time and the sperm morphology. Higher risks of asthenozoospermia (adjusted odds ratio [OR] = 2.06, 95% confidence interval [CI]: 1.31-3.25, P = 0.002) and teratozoospermia (adjusted OR = 1.98, 95% CI: 1.10-3.55, P = 0.02) were observed in Q3 than those in Q1. Our results indicate that a higher risk of abnormal semen parameter values was associated with an increase in time for semen collection, which may be related to male fertility through its association with semen quality.
Male ; Humans ; Semen Analysis ; Semen ; Sperm Motility ; Sperm Count ; Asthenozoospermia ; Spermatozoa

Male infertility caused by idiopathic oligoasthenospermia (OAT) is known as idiopathic male infertility. Glutathione S-transferase (GST) and fluoride may play important roles in idiopathic male infertility, but their effects are still unknown. Our study examined the relationship between GST polymorphisms and fluoride-induced toxicity in idiopathic male infertility and determined the underlying mechanism. Sperm, blood, and urine samples were collected from 560 males. Fluoride levels were measured by a highly selective electrode method, and GST genotypes were identified using polymerase chain reaction (PCR) and PCR-restriction fragment length polymorphism (PCR-RFLP). Semen parameters, DNA fragmentation index (DFI), mitochondrial membrane potential (MMP), and oxidative stress (OS) biomarkers were statistically assessed at the P < 0.05 level. Compared with healthy fertile group, semen parameters, fluoride levels, OS biomarkers, sex hormone levels, and MMP and DFI levels were lower in the idiopathic male infertility group. For glutathione S-transferase M1 (GSTM1[-]) and glutathione S-transferase T1 (GSTT1[-]) or glutathione S-transferase P1 (GSTP1) mutant genotypes, levels of semen fluoride, OS, MMP, and DFI were considerably higher, and the mean levels of sperm parameters and testosterone were statistically significant in GSTM1(+), GSTT1(+), and GSTP1 wild-type genotypes. Both semen and blood fluoride levels were associated with oxidative stress in idiopathic male infertility patients. Elevated fluoride in semen with the genotypes listed above was linked to reproductive quality in idiopathic male infertility patients. In conclusion, GST polymorphisms and fluorine may have an indicative relationship between reproductive quality and sex hormone levels, and OS participates in the development of idiopathic male infertility.
Humans ; Male ; Fluorides/adverse effects* ; Semen ; Polymorphism, Genetic ; Glutathione Transferase/genetics* ; Glutathione S-Transferase pi/genetics* ; Infertility, Male/genetics* ; Genotype ; Biomarkers ; Genetic Predisposition to Disease ; Case-Control Studies

Multiple morphological abnormalities of the sperm flagella (MMAF) is a severe form of asthenozoospermia categorized by immotile spermatozoa with abnormal flagella in ejaculate. Whole-exome sequencing (WES) is used to detect pathogenic variants in patients with MMAF. In this study, a novel homozygous frameshift variant (c.6158_6159insT) in dynein axonemal heavy chain 8 (DNAH8) from two infertile brothers with MMAF in a consanguineous Pakistani family was identified by WES. Reverse transcription-polymerase chain reaction (RT-PCR) confirmed DNAH8 mRNA decay in these patients with the DNAH8 mutation. Hematoxylin-eosin staining and transmission electron microscopy revealed highly divergent morphology and ultrastructure of sperm flagella in these patients. Furthermore, an immunofluorescence assay showed the absence of DNAH8 and a reduction in its associated protein DNAH17 in the patients' spermatozoa. Collectively, our study expands the phenotypic spectrum of patients with DNAH8-related MMAF worldwide.
Humans ; Male ; Consanguinity ; Pakistan ; Infertility, Male/metabolism* ; Semen/metabolism* ; Sperm Tail/metabolism* ; Spermatozoa/metabolism* ; Flagella/pathology* ; Mutation

This study assessed the effects of a simulated high-altitude environment on the reproductive system of prepubertal male rats and the reversibility of these effects upon return to a normal environment. Three-week-old male Wistar rats were randomly allocated to 4 groups that were exposed to different conditions: a normal environment for 6 weeks and 12 weeks, respectively, hypobaric hypoxia for 6 weeks, and hypobaric hypoxia for 6 weeks followed by a normal environment for 6 weeks. Multiple pathophysiological parameters were evaluated at the histological, endocrine, and molecular levels. Hypobaric hypoxia exposure for 6 weeks during the prepubertal phase significantly altered physiological parameters, body functions, blood indices, and reproductive potential. Six weeks after returning to a normal environment, the damaged reproductive functions partially recovered due to compensatory mechanisms. However, several changes were not reversed after returning to a normal environment for 6 weeks, including disorders of body development and metabolism, increased red blood cells, increased fasting blood glucose, abnormal blood lipid metabolism, decreased testicular and epididymis weights, abnormal reproductive hormone levels, excessive apoptosis of reproductive cells, and decreased sperm concentration. In summary, a hypobaric hypoxic environment significantly impaired the reproductive function of prepubertal male rats, and a return to normal conditions during the postpubertal phase did not fully recover these impairments.
Rats ; Male ; Animals ; Rats, Wistar ; Altitude ; Semen/metabolism* ; Hypoxia/pathology* ; Genitalia, Male