RNA m6A modification regulates L1 retrotransposons in human spermatogonial stem cell differentiation in vitro and in vivo.

The maintenance of genome integrity in the germline is crucial for mammalian development. Long interspersed element type 1 (LINE-1, L1) is a mobile genetic element that makes up about 17% of the human genome and poses a threat to genome integrity. N6-methyl-adenosine (m6A) plays an essential role in regulating various biological processes. However, the function of m6A modification in L1 retrotransposons and human germline development remains largely unknown. Here we knocked out the m6A methyltransferase METTL3 or the m6A reader YTHDF2 in human embryonic stem cells (hESCs) and discovered that METTL3 and YTHDF2 are crucial for inducing human spermatogonial stem cells (hSSCs) from hESCs in vitro. The removal of METTL3 or YTHDF2 resulted in increased L1 retrotransposition and reduced the efficiency of SSC differentiation in vitro. Further analysis showed that YTHDF2 recognizes the METTL3-catalyzed m6A modification of L1 retrotransposons and degrades L1 mRNA through autophagy, thereby blocking L1 retrotransposition. Moreover, the study confirmed that m6A modification in human fetal germ cells promotes the degradation of L1 retrotransposon RNA, preventing the insertion of new L1 retrotransposons into the genome. Interestingly, L1 retrotransposon RNA was highly expressed while METTL3 was significantly downregulated in the seminal plasma of azoospermic patients with meiotic arrest compared to males with normal fertility. Additionally, we identified some potentially pathogenic variants in m6A-related genes in azoospermic men with meiotic arrest. In summary, our study suggests that m6A modification serves as a guardian of genome stability during human germline development and provides novel insights into the function and regulatory mechanisms of m6A modification in restricting L1 retrotransposition.

A comprehensive meta-analysis to identify susceptibility genetic variants for precocious puberty.

PURPOSE: Currently, several genetic variants in ERα gene (rs2234693 and rs9340799), ERß gene (rs1256049 and rs4986938), KISS1 gene (rs4889, rs1132506 and rs5780218), LIN28B gene (rs314263, rs314276 and rs314280), and MKRN3 gene (rs2239669) have been repeatedly explored for their contribution to precocious puberty (PP) susceptibility. However, the results remain conflicting rather than conclusive. We here performed a meta-analysis to identify the real susceptibility genetic variants for PP. METHODS: After screening by inclusion criteria, 20 related studies were finally included in this meta-analysis. The odds ratios and 95% confidence intervals were calculated to assess the strength of association. Sensitive analysis, publication bias, and trial sequential analysis (TSA) were performed to evaluate the stability and reliability of results. RESULTS: Rs2234693, rs9340799, and rs1256049 were significantly associated with PP susceptibility (p < 0.0084). Stratified analysis according to ethnicity showed that rs2234693 and rs9340799 were significantly associated with PP susceptibility in Asian and Chinese populations. Stratified analysis according to PP subtype showed that rs2234693 and rs9340799 were significantly associated with idiopathic central PP susceptibility in Asian and Chinese populations (p < 0.0084). The results of publication bias, sensitivity analysis, and TSA provided solid evidence for the association between these three variants and PP susceptibility. CONCLUSIONS: Rs2234693 and rs9340799 in ERα gene and rs1256049 in ERß gene may serve as susceptive factors for PP development. The present finding should be confirmed in replication studies and reinforced in functional studies, which will ultimately improve the feasibility of the application of these three PP-susceptible loci in clinical practice.

Exosomes derived from umbilical cord mesenchymal stem cells ameliorate male infertility caused by busulfan in vivo and in vitro.

Environmental pollution has emerged as a global concern due to its detrimental effects on human health. One of the critical aspects of this concern is the impact of environmental pollution on sperm quality in males. Male factor infertility accounts for approximately 40%- 50% of all infertility cases. Nonobstructive azoospermia (NOA) is the most severe type of male infertility. Human umbilical cord mesenchymal stem cell (hUCMSC) exosomes enhance proliferation and migration, playing crucial roles in tissue and organ injury repair. However, whether hUCMSC exosomes impacting on NOA caused by chemotherapeutic agents remains unknown. This study aimed to explore the functional restoration and mechanism of hUCMSC exosomes on busulfan-induced injury in GC-1 spg cells and ICR mouse testes. Our results revealed that hUCMSC exosomes effectively promoted the proliferation and migration of busulfan-treated GC-1 spg cells. Additionally, oxidative stress and apoptosis were significantly reduced when hUCMSC exosomes were treated. Furthermore, the injection of hUCMSC exosomes into the testes of ICR mice treated with busulfan upregulated the expression of mouse germ cell-specific genes, such as vasa, miwi, Stra8 and Dazl. Moreover, the expression of cellular junction- and cytoskeleton-related genes, including connexin 43, ICAM-1, ß-catenin and androgen receptor (AR), was increased in the testicular tissues treated with exosomes. Western blot analysis demonstrated significant downregulation of apoptosis-associated proteins, such as bax and caspase-3, and upregulation of bcl-2 in the mouse testicular tissues injected with hUCMSC exosomes. Further, the spermatogenesis in the experimental group of mice injected with exosomes showed partial restoration of spermatogenesis compared to the busulfan-treated group. Collectively, these findings provide evidence for the potential clinical applications of hUCMSC exosomes in cell repair and open up new avenues for the clinical treatment of NOA.

Association of urinary and seminal plasma vanadium concentrations with semen quality: A repeated-measures study of 1135 healthy men.

Although animal studies have shown the reproductive toxicity of vanadium, less is known about its effects on semen quality in humans. Among 1135 healthy men who were screened as potential semen donors, we investigated the relationships of semen quality with urinary and seminal plasma vanadium levels via inductively coupled plasma-mass spectrometry (ICP-MS). Spearman rank correlation tests and linear regression models were used to assess the correlations between average urinary and within-individual pooled seminal plasma vanadium concentrations (n = 1135). We utilized linear mixed-effects models to evaluate the associations of urinary and seminal plasma vanadium levels (n = 1135) with repeated sperm quality parameters (n = 5576). Seminal plasma vanadium concentrations were not significantly correlated with urinary vanadium concentrations (r = 0.03). After adjusting for possible confounders, we observed inverse relationships of within-individual pooled seminal plasma vanadium levels with total count, semen volume, and sperm concentration (all P values for trend < 0.05). Specifically, subjects in the highest (vs. lowest) tertile of seminal plasma vanadium concentrations had - 11.3% (-16.4%, -5.9%), - 11.1% (-19.1%, -2.4%), and - 20.9% (-29.0%, -11.8%) lower sperm volume, concentration, and total count, respectively; moreover, urinary vanadium levels appeared to be negatively associated with sperm motility. These relationships showed monotonically decreasing dose-response patterns in the restricted cubic spline analyses. Our results demonstrated a poor correlation between urinary and seminal plasma levels of vanadium, and elevated vanadium concentrations in urine and seminal plasma may be adversely related to male semen quality.

INO80 governs superenhancer-mediated oncogenic transcription and tumor growth in melanoma.

Superenhancers (SEs) are large genomic regions with a high density of enhancer marks. In cancer, SEs are found near oncogenes and dictate cancer gene expression. However, how oncogenic SEs are regulated remains poorly understood. Here, we show that INO80, a chromatin remodeling complex, is required for SE-mediated oncogenic transcription and tumor growth in melanoma. The expression of Ino80, the SWI/SNF ATPase, is elevated in melanoma cells and patient melanomas compared with normal melanocytes and benign nevi. Furthermore, Ino80 silencing selectively inhibits melanoma cell proliferation, anchorage-independent growth, tumorigenesis, and tumor maintenance in mouse xenografts. Mechanistically, Ino80 occupies >90% of SEs, and its occupancy is dependent on transcription factors such as MITF and Sox9. Ino80 binding reduces nucleosome occupancy and facilitates Mediator recruitment, thus promoting oncogenic transcription. Consistently, genes co-occupied by Ino80 and Med1 are selectively expressed in melanomas compared with melanocytes. Together, our results reveal an essential role of INO80-dependent chromatin remodeling in SE function and suggest a novel strategy for disrupting SEs in cancer treatment.

Exogenous Metals Atlas in Spermatozoa at Single-Cell Resolution in Relation to Human Semen Quality.

While exogenous metal/metalloid (metal) exposure has been associated with reduced human semen quality, no study has assessed the associations of exogenous metals in human spermatozoa with semen quality. Here, we developed a strategy to explore the associations between exogenous metals in spermatozoa at single-cell resolution and human semen quality among 84 men screened as sperm donors, who provided 266 semen samples within 90 days. A cellular atlas of exogenous metals at the single-cell level was created with mass cytometry (CyTOF) technology, which concurrently displayed 18 metals in more than 50 000 single sperm. Exogenous metals in spermatozoa at single-cell resolution were extremely heterogeneous and diverse. Further analysis using multivariable linear regression and linear mixed-effects models revealed that the heterogeneity and prevalence of the exogenous metals at single-cell resolution were associated with semen quality. The heterogeneity of lead (Pb), tin (Sn), yttrium (Y), and zirconium (Zr) was negatively associated with sperm concentration and count, while their prevalence showed positive associations. These findings revealed that the heterogeneous properties of exogenous metals in spermatozoa were associated with human semen quality, highlighting the importance of assessing exogenous metals in spermatozoa at single-cell resolution to evaluate male reproductive health risk precisely.

The positive impact of the NtTAS14-like1 gene on osmotic stress response in Nicotiana tabacum.

KEY MESSAGE: NtTAS14-like1 enhances osmotic tolerance through coordinately activating the expression of osmotic- and ABA-related genes. Osmotic stress is one of the most important limiting factors for tobacco (Nicotiana tabacum) growth and development. Dehydrin proteins are widely involved in plant adaptation to osmotic stress, but few of these proteins have been functionally characterized in tobacco. Here, to identify genes required for osmotic stress response in tobacco, an encoding dehydrin protein gene NtTAS14-like1 was isolated based on RNA sequence data. The expression of NtTAS14-like1 was obviously induced by mannitol and abscisic acid (ABA) treatments. Knock down of NtTAS14-like1 expression reduced osmotic tolerance, while overexpression of NtTAS14-like1 conferred tolerance to osmotic stress in transgenic tobacco plants, as determined by physiological analysis of the relative electrolyte leakage and malonaldehyde accumulation. Further expression analysis by quantitative real-time PCR indicated that NtTAS14-like1 participates in osmotic stress response possibly through coordinately activating osmotic- and ABA-related genes expression, such as late embryogenesis abundant (NtLEA5), early responsive to dehydration 10C (NtERD10C), calcium-dependent protein kinase 2 (NtCDPK2), ABA-responsive element-binding protein (NtAREB), ABA-responsive element-binding factor 1 (NtABF1), dehydration-responsive element-binding genes (NtDREB2A), xanthoxin dehydrogenase/reductase (NtABA2), ABA-aldehyde oxidase 3 (NtAAO3), 9-cis-epoxycarotenoid dioxygenase (NtNCED3). Together, this study will facilitate to improve our understandings of molecular and functional properties of plant TAS14 proteins and to improve genetic evidence on the involvement of the NtTAS14-like1 in osmotic stress response of tobacco.

Sperm mitochondrial DNA copy number mediates the association between seminal plasma selenium concentrations and semen quality among healthy men.

Selenium (Se) is essential for successful male reproduction. However, the association of Se status with human semen quality remains controversial and the underlying mechanisms are poorly understood. We measured seminal plasma Se concentrations, sperm mitochondrial DNA copy number (mtDNAcn), and sperm quality parameters among healthy Chinese men screened as potential sperm donors. Linear mixed-effects models were used to investigate the associations of within-subject pooled seminal plasma Se concentrations (n = 1159) with repeated sperm quality parameters (n = 5617); mediation analyses were applied to evaluate the mediating role of sperm mtDNAcn (n = 989). Seminal plasma Se concentrations were positively associated with sperm concentration and total count (both P for trend < 0.001). In adjusted models, men in the top vs. bottom quartiles of seminal plasma Se concentrations had 70.1 % (95 % CI: 53.3 %, 88.9 %) and 59.1 % (95 % CI: 40.5 %, 80.2 %) higher sperm concentration and total count, respectively. Meanwhile, we observed inverse associations between seminal plasma Se concentrations and sperm mtDNAcn, and between sperm mtDNAcn and sperm motility, concentration, and total count (all P for trend < 0.05). Mediation analyses suggested that sperm mtDNAcn mediated 19.7 % (95 % CI: 15.9 %, 25.3 %) and 23.1 % (95 % CI: 17.4 %, 33.4 %) of the associations between seminal plasma Se concentrations and sperm concentration and total count, respectively. Our findings suggest that Se is essential for male spermatogenesis, potentially by affecting sperm mtDNAcn.

[Delivery of epididymis-specific mRNAs from mouse epididymosomes into N2a and TM4 cells].

OBJECTIVE: To investigate whether mouse epididymis-specific mRNAs Adam7 and Crisp1 can be delivered into N2a and TM4 cells, and to provide an experimental basis for exploring the function of epididymal mRNAs. METHODS: Using RT-PCR, we detected the presence of epididymis-specific genes (Adam7, Crisp1, Defb22, Wfdc2, and Wfdc9) in the testis, epididymis, epididymosome and sperm of adult male BALB/c mice as well as in the human testis, seminal vesicles and sperm. We isolated epididymosomes of BALB/c mice by low-speed centrifugation, filtration and ultracentrifugation, fluorescently labeled them by PKH26, co-incubated them for 1 hour with the N2a and TM4 cells after 24 hours of starvation culture, and observed whether they were fused with the N2a and TM4 cells and ingested using the epididymosomes without PKH26 labeling, PKH26 dye without epididymosomes, and non- epididymosome or -PKH26 dye as controls. Then we detected the epididymis-specific genes in the N2a and TM4 cells after 1-hour co-incubation by RT-PCR. RESULTS: Adam7 and Crisp1 were present in the mouse epididymis, epididymosomes and sperm, and in the human seminal vesicles and sperm as well, but not in the testes of either the mice or men. PKH26 and Hoechst33258 fluorescence double-labeling showed that the mouse epididymosomes were fused with the N2a and TM4 cells and ingested; RT-PCR revealed the mRNAs of Adam7 and Crisp1 in the N2a and TM4 cells after 1-hour co-incubation; and Western blot exhibited the CRISP1 protein in the N2a and TM4 cells incubated with epididymosomes. CONCLUSION: Epididymosomes can deliver epididymis-specific mRNAs Adam7 and Crisp1 into N2a and TM4 cells, where Crisp1 may be translated into proteins, though their function and significance need to be further studied.

Diurnal rhythm of human semen quality: analysis of large-scale human sperm bank data and timing-controlled laboratory study.

STUDY QUESTION: Can we identify diurnal oscillations in human semen parameters as well as peak times of semen quality? SUMMARY ANSWER: Human semen parameters show substantial diurnal oscillation, with most parameters reaching a peak between 1100 and 1500 h. WHAT IS KNOWN ALREADY: A circadian clock appears to regulate different physiological functions in various organs, but it remains controversial whether diurnal rhythms occur in human semen parameters. STUDY DESIGN, SIZE, DURATION: The medical record of a provincial human sperm bank (HSB) with 33 430 semen samples collected between 0800 and 1700 h from 1 March 2010 to 8 July 2015 was used to analyze variation in semen parameters among time points. A laboratory study was conducted to collect semen samples (n = 36) from six volunteers at six time points with identical time intervals (2 days plus 4 h) between 6 June and 8 July in 2019, in order to investigate the diurnal oscillation of semen parameters in vivo, with a strictly controlled abstinence period. Therefore, the sperm bank study with a large sample size and the in vivo study with a strictly controlled abstinence period in a 24-h time window could be compared to describe the diurnal rhythms in human semen parameters. PARTICIPANTS/MATERIALS, SETTING, METHODS: Samples were obtained from potential HSB donors and from participants in the laboratory study who were volunteers, recruited by flyers distributed in the community. Total sperm count, sperm concentration, semen volume, progressive motility and total motility were assessed using computer-aided sperm analysis. In addition, sperm chromatin integrity parameters (DNA fragmentation index and high DNA stainability) were assessed by the sperm chromatin structure assay, and sperm viability was measured with flow cytometry in the laboratory study. MAIN RESULTS AND THE ROLE OF CHANCE: The 33 430 samples from the HSB showed a temporal variation in total sperm count, sperm concentration, semen volume, progressive motility and total motility (all P < 0.001) between 0800 and 1700 h. Consequently, the eligibility of semen samples for use in ART, based on bank standards, fluctuated with time point. Each hour earlier/later than 1100 h was associated with 1.14-fold risk of ineligibility. Similarly, the 36 samples taken during the 24-h time window showed diurnal oscillation. With the pre-collection abstinence period strictly controlled, most semen parameters reached the most favorable level between 1100 and 1500 h. LIMITATIONS, REASONS FOR CAUTION: Some of the possible confounding factors, such as energy intake, which might influence semen quality or diurnal rhythms, were not adjusted for in the analyses. In addition, the findings should be considered with caution because the study was conducted in a specific population, time and place, while the timing of oscillations could differ with changing conditions. WIDER IMPLICATIONS OF THE FINDINGS: The findings could help us to estimate semen quality more precisely and to obtain higher quality sperm for use in ART and in natural conception. STUDY FUNDING/COMPETING INTEREST(S): This study was supported by the National Natural Science Foundation of China (81871208) and National Key R&D Program of China (2017YFC1002001). There are no conflicts of interest to declare. TRIAL REGISTRATION NUMBER: N/A.

Sperm mitochondrial DNA copy number in relation to semen quality: A cross-sectional study of 1164 potential sperm donors.

OBJECTIVE: To investigate the association between mitochondrial DNA copy number (mtDNAcn) and semen quality. DESIGN: A cross-sectional study. SETTING: Hubei Province Human Sperm Bank of China (from April 2017 to July 2018). POPULATION: A total of 1164 healthy male sperm donors with 5739 specimens. MAIN OUTCOME MEASURES: Real-time quantitative polymerase chain reaction (RT-PCR) was used to measure sperm mtDNAcn. We also determined semen volume, concentration and motility parameters (progressive motility, nonprogressive motility and immotility). METHODS: Mixed-effect models and general linear models were uses. RESULTS: After adjusting for relevant confounding factors, mixed-effect models revealed diminished sperm motility (progressive and total), concentration, and total count across the quartiles of mtDNAcn (all P < 0.05). Compared with men in the lowest quartile, men in the highest quartile of mtDNAcn had lower progressive sperm motility, total motility, concentration and total count of -8.9% (95% CI -12.7% to -5.0%), -8.0% (95% CI -11.6% to -4.4%), -42.8% (95% CI -47.7% to -37.4%), and - 44.3% (95% CI -50.1% to -37.7%), respectively. These inverse dose-response relationships were further confirmed in the cubic spline models, where mtDNAcn was modelled as a continuous variable. CONCLUSIONS: We found that mtDNAcn was inversely associated with semen quality in a dose-dependent manner. Our results provide novel clues that sperm mtDNAcn may serve as a useful predictor of human semen characteristics. TWEETABLE ABSTRACT: Sperm mitochondrial DNA copy number was markedly associated with diminished sperm motility (progressive and total), concentration and total count.

The dose-effect relationships of cigarette and alcohol consumption with depressive symptoms: a multiple-center, cross-sectional study in 5965 Chinese middle-aged and elderly men.

BACKGROUND: Although association of depressive symptoms with cigarette or alcohol is well documented, the dose-response relationship between them is rarely studied. This study aims to evaluate dose-response relationships of cigarette and alcohol consumption with depressive symptoms in Chinese middle-aged and elderly men, providing evidence to guide cigarette and alcohol control. METHODS: This multiple-center, cross-sectional study including 5965 Chinese men aged 40-79 years was conducted in 2013-2016 in China. Depressive symptoms were evaluated by Beck Depression Inventory-Short Form. History of cigarette smoking and alcohol drinking were collected with a structured questionnaire. Prevalence of depressive symptoms was compared depending on cigarette and alcohol consumption. Adjusted odds ratios (OR) and 95% confidence interval (CI) were estimated by binary logistic regression. Interpolation analysis was applied to test dose-effect relationships. RESULTS: A parabolic-shaped relationship was observed between cigarette consumption and depressive symptoms. Compared to never smokers, 59.0% (OR = 1.59, 95% CI 1.30-1.94) and 29.0% (OR = 1.29, 95% CI 1.08-1.54) higher odds of depressive symptoms were observed in men smoking < 10 cigarettes/day and 10-20 cigarettes/day, whereas, similar odds of depressive symptoms among men smoking > 20 cigarettes/day (P = 0.092). An inverted J-shaped relationship was observed between alcohol consumption and depressive symptoms. Compared to never drinkers, a tendency of higher prevalence of depressive symptoms (OR = 1.16, 95% CI 0.99-1.36) was observed in men drinking < 140 g/week, and similar prevalence was observed in those drinking 140-280 g/week (P = 0.920), whereas, 29.4% (OR = 0.71, 95% CI 0.57-0.88) lower odds in men drinking > 280 g/week. CONCLUSIONS: Associations of cigarette smoking and alcohol drinking with depressive symptoms differ with consumption in middle-aged and elderly men. Health-care providers should exercise great caution on depressive symptoms in conducting cigarette and alcohol control.

Epigenetic regulation of mRNA N6-methyladenosine modifications in mammalian gametogenesis.

N6-methyladenosine (m6A) is the most prevalent epigenetic modification of mRNAs and broadly influences various biological processes by regulating post-transcriptional gene expression in eukaryotes. The reversible m6A modification is catalyzed by methyltransferases, METTL3 and METTL14 (writers), removed by the demethylases FTO and ALKBH5 (erasers) and recognized by m6A-binding proteins, namely the YTH domain-containing family of proteins (readers). Both m6A modification and the related enzymes are involved in the regulation of normal gametogenesis and embryonic development in many species. Recent studies showed that loss of m6A compromises gamete maturation, sex hormone synthesis, fertility and early embryonic development. In this review, we have summarized the most recent findings on the role of mRNA m6A modification in mammalian gametogenesis to emphasize the epigenetic regulation of mRNA in the reproductive system.

Clinical application value of Inhibin B alone or in combination with other hormone indicators in subfertile men with different spermatogenesis status: A study of 324 Chinese men.

BACKGROUND: In this study, we investigated the clinical value of serum Inhibin B alone or in combination with other hormone indicators in subfertile men. METHODS: This is a multicenter study involving 324 men from different cities in China. Testicular volume, routine semen analysis, serum Inhibin B, anti-Müllerian hormone (AMH), follicle-stimulating hormone (FSH), luteinizing hormone (LH), testosterone, estradiol, and prolactin were measured. Testicular tissue samples were also analyzed in 78 of 129 patients with azoospermia to distinguish impaired spermatogenesis from obstructive azoospermia. RESULTS: The concentration of Inhibin B, FSH, and AMH is related to spermatogenesis. For men with impaired spermatogenesis, including mild-to-moderate oligozoospermia (IMO) and severe oligozoospermia (ISO), serum levels of Inhibin B and FSH are highly correlated with sperm counting. However, in patients with idiopathic moderate oligozoospermia or severe oligozoospermia, there was no significant correlation between Inhibin B (or FSH) and sperm concentration. The upper cutoff value of Inhibin B to diagnose ISO is 58.25 pg/ml with a predictive accuracy of 80.65%. To distinguish between nonobstructive azoospermia (NOA) and obstructive azoospermia (OA), the area under the curve (AUC) for AMH + Inhibin B + FSH is very similar to Inhibin B (0.943 vs. 0.941). The cutoff level of Inhibin B to diagnose nonobstructive azoospermia is 45.9 pg/ml with a positive and negative prediction accuracy of 97.70% and 85.71%, respectively. CONCLUSION: In summary, Inhibin B is a promising biomarker alone or in combination with other hormone indicators for the diagnosis of testicular spermatogenesis status, helping clinical doctors to distinguish NOA from OA.

Secretions released from mesenchymal stem cells improve spermatogenesis restoration of cytotoxic treatment with busulfan in azoospermia mice.

This study aimed at the efficacy of sequential treatment of bone marrow-derived mesenchymal stem cell secretion for busulfan-treated azoospermia in mice. The conditioned media (CM) was obtained from bone marrow mesenchymal stem cells (MSCs) or 293 cells. Chemically induced azoospermia mice received 200 µl MSC-CM or 293-CM twice a week intravenously for three consecutive weeks. The histological assessment of spermatogenic recovery quantifying the expression of meiosis-associated genes, and Sertoli cell barrier functional factors were assessed. The characteristics of TM4 cells (Sertoli cell line) after pre-incubation of MSC-CM in vitro were also obtained. The MSC-CM group had the most spermatogenic colonies among the three groups (p < .05), but no spermatids were seen. Expressions of the meiosis-associated genes Dazl, Vasa, Miwi, Stra8, CyclinA1, Pgk2 and Scp3 in MSC-CM testis were remarkably higher compared with 293-CM and busulfan groups respectively (p < .05). The levels of Sertoli cell barrier functional factors, for example ICAM-1 and N-cadherin, were significantly increased during MSC-CM treatment (p < .05). Moreover, pre-incubation of MSC-CM particularly accelerated the CD54 (ICAM-1) and CD44 expressions of TM4 cells and promoted cell inherent adhesion. MSC-CM treatment can significantly improve the short-term restoration of spermatogonial structures of chemically induced azoospermia related to facilitating Sertoli cell adhesion integrity.

[Functional polymorphism sites in non-coding regions of folate metabolism-related genes in the reproductive-aged population of Hubei Province].

Objective: To investigate the distribution of the functional polymorphisms in the non-coding regions of folate metabolism-related genes in the reproductive-aged population of Hubei Province. METHODS: Using Sanger sequencing, we examined the polymorphisms of the genes MTR (rs28372871 and rs1131450), MTRR (rs326119) and CBS (rs2850144) in 790 subjects before and during pregnancy from April 2020 to March 2021. We compared the distributions of the four loci between different populations. RESULTS: The distributions of the four genotypes of rs28372871, rs1131450, rs326119 and rs2850144 all conformed to the Hardy-Weinberg equilibrium (HWE). Statistically significant differences were observed in the polymorphism distribution of rs28372871 between Hubei and Jiangsu (P < 0.05), in that of rs1131450 between Hubei and Shanghai (P < 0.05), and in that of rs2850144 between Hubei and Yazd, Iran (P < 0.01). CONCLUSIONS: This was the first investigation on the distribution of MTR, MTRR and CBS gene polymorphisms in the reproductive-aged population of Hubei Province. The effects of the functional loci in both encoding and non-coding regions of folate metabolism-related genes have to be comprehensively considered so as to formulate an appropriate folate-supplementary protocol.

Potential risks of SARS-CoV-2 infection on reproductive health.

The outbreak of 2019 novel coronavirus disease (COVID-19) has become a major pandemic threat worldwide. Such a public health emergency can greatly impact various aspects of people's health and lives. This paper focuses on its potential risks for reproductive health, including the reproductive system and its functioning, as well as gamete and embryo development, which could be affected by the virus itself, drug treatments, chemical disinfectants and psychological effects related to panic during the COVID-19 outbreak.

Association between BMI and semen quality: an observational study of 3966 sperm donors.

STUDY QUESTION: What is the relationship between abnormal BMI and semen quality? SUMMARY ANSWER: Underweight was significantly associated with lower sperm concentration, total sperm number and total motile sperm count, while overweight was significantly associated with lower semen volume, total sperm number and total motile sperm count. WHAT IS KNOWN ALREADY: Abnormal BMI has been associated with lower semen quality, but the results remain somewhat controversial. In addition, most previous studies have focused on the influence of obesity or overweight on semen quality, and evidence on the association between underweight and semen quality is rare. STUDY DESIGN, SIZE, DURATION: This research was an observational study investigating 3966 sperm donors from a large sperm bank in Wuhan city, China. These donors passed the screening for sperm donation and underwent 29 949 semen examinations between 1 January 2013 and 9 April 2018. PARTICIPANTS/MATERIALS, SETTING, METHODS: BMI was categorized into four groups: underweight (<18.5 kg/m2), normal weight (18.5-24.9 kg/m2), overweight (25-29.9 kg/m2) and obese (≥30 kg/m2). Semen volume, sperm concentration, total sperm number, total motility, progressive motility and total motile sperm count were determined by trained clinical technicians. Linear mixed models were used to conduct dose-response analyses between BMI and semen quality parameters. MAIN RESULTS AND THE ROLE OF CHANCE: Underweight was significantly associated with a 3.0% (95% CI: 0.1%, 5.8%), 6.7% (1.9%, 11.3%) and 7.4% (2.2%, 12.4%) reduction in sperm concentration, total sperm number and total motile sperm count, respectively. Overweight was significantly associated with a 4.2% (1.6%, 6.8%), 3.9% (0.9%, 6.9%) and 3.6% (0.2%, 6.9%) reduction in semen volume, total sperm number and total motile sperm count, respectively. Non-linear models including continuous BMI as a natural cubic spline function yielded similar results. LIMITATIONS, REASONS FOR CAUTION: Our study subjects were sperm donors who are typically young and healthy, and therefore not representative of the general male population. Caution should be paid in generalizing our results to other populations. Furthermore, we did not measure the donors' weight repeatedly along with each semen donation; instead, we only measured it once during the screening, which may cause bias due to the variations of weight across time. WIDER IMPLICATIONS OF THE FINDINGS: Our study provides evidence that underweight and overweight are associated with lower semen quality, and highlights the importance of maintaining a normal weight for men. STUDY FUNDING/COMPETING INTEREST(S): This work was supported by the Health and Family Planning Commission of Hubei Province (Grant number WJ2015MA027), the Hubei Provincial Committee of the Communist Youth League of China, and Center for Global and Regional Environmental Research at the University of Iowa. The authors declare that there are no conflicts of interest. TRIAL REGISTRATION NUMBER: N/A.

Physical activity and sedentary time in relation to semen quality in healthy men screened as potential sperm donors.

STUDY QUESTION: Is physical activity or sedentary time associated with semen quality parameters? SUMMARY ANSWER: Among healthy men screened as potential sperm donors, higher self-reported physical activity was associated with increased progressive and total sperm motility. WHAT IS KNOWN ALREADY: Despite the claimed beneficial effect of moderate physical activity on semen quality, results from epidemiological studies have been inconclusive. Previous studies were mostly conducted among endurance athletes or male partners of couples who sought infertility treatment. STUDY DESIGN, SIZE, DURATION: Healthy men screened as potential sperm donors were recruited at the Hubei Province Human Sperm Bank of China. Between April 2017 and July 2018; 746 men completed the long-form International Physical Activity Questionnaire (IPAQ) and provided repeated semen samples (n = 5252) during an approximately 6-month period. PARTICIPANTS/MATERIALS, SETTING, METHODS: Total metabolic equivalents (METs), moderate-to-vigorous METs and sedentary time were abstracted from the IPAQ. Sperm concentration, total sperm count, progressive motility and total motility in repeated specimens were determined by trained clinical technicians. Mixed-effect models were applied to investigate the relationships between physical activity and sedentary time and repeated measures of semen quality parameters. MAIN RESULTS AND THE ROLE OF CHANCE: After adjusting for multiple confounders, total METs and moderate-to-vigorous METs were both positively associated with progressive and total sperm motility. Compared with men in the lowest quartiles, those in the highest quartiles of total and moderate-to-vigorous METs had increased progressive motility of 16.1% (95% CI: 6.4, 26.8%) and 17.3% (95% CI: 7.5, 27.9%), respectively, and had increased total motility of 15.2% (95% CI: 6.2, 24.9%) and 16.4% (95% CI: 7.4, 26.1%), respectively. Sedentary time was not associated with semen quality parameters. LIMITATIONS, REASONS FOR CAUTION: The IPAQ was reported only once from study participants; measurement errors were inevitable and may have biased our results. Furthermore, although we have adjusted for various potential confounders, the possibility of unmeasured confounding cannot be fully ruled out. WIDER IMPLICATIONS OF THE FINDINGS: Our findings suggest that maintaining regular exercise may improve semen quality parameters among healthy, non-infertile men. Specifically, we found that higher self-reported total and moderate-to-vigorous METs were associated with improved sperm motility, which reinforces the existing evidence that physical activity may improve male reproductive health. STUDY FUNDING/COMPETING INTEREST(S): Y.-X.W was supported by the Initiative Postdocs Supporting Program (No. BX201700087). A.P. was supported by the National Key Research and Development Program of China (2017YFC0907504). C.-L.X. was supported by the National Key Research and Development Program of China (2016YFC1000206). The authors report no conflicts of interest. TRIAL REGISTRATION NUMBER: N/A.

Mesenchymal stem cell-secreted factors delayed spermatogenesis injuries induced by busulfan involving intercellular adhesion molecule regulation.

The present study was designed to investigate the therapeutic effect of bone marrow MSC-derived factors on gonadotropic toxicity induced by busulfan in vivo. The conditioned media (CM) was obtained from MSCs in serum-free incubation for 48 hr and concentrated ~25-fold by ultrafiltration. The CM of HEK 293 cells was treated as control (293-CM). MSC-CM was injected into busulfan mice via caudal veins after 1 day of busulfan treatment for 2 weeks (200 µl per dose/twice weekly）. Compared to the 293-CM group, testicular injury was delayed in MSC-CM group, including reduced vacuolations of cells in the basal compartment of the seminiferous epithelium and detachment of cells from basement membrane. Apoptotic spermatogenic cells were significantly decreased in MSC-CM group (p ï¼œ 0.05). Interesting N-cadherin，ICAM-1 and P-cadherin expressions significantly increased in MSC-CM group, while occludin, ZO-1 and connexin 43 expressions showed no difference among MSC-CM, 293-CM and busulfan groups. Present results suggest MSC-secreted factors protect spermatogenesis impairment after busulfan treatment by reducing the apoptosis of spermatogenic cells and enhancing intercellular adhesion molecule expressions.