Continuous self-renewal and differentiation of spermatogonial stem cells (SSCs) is vital for maintenance of adult spermatogenesis. Although several spermatogonial stem cell regulators have been extensively investigated in rodents, regulatory mechanisms of human SSC self-renewal and differentiation have not been fully established. We analyzed single-cell sequencing data from the human testis and found that forkhead box P4 (FOXP4) expression gradually increased with development of SSCs. Further analysis of its expression patterns in human testicular tissues revealed that FOXP4 specifically marks a subset of spermatogonia with stem cell potential. Conditional inactivation of FOXP4 in human SSC lines suppressed SSC proliferation and significantly activated apoptosis. FOXP4 expressions were markedly suppressed in tissues with dysregulated spermatogenesis. These findings imply that FOXP4 is involved in human SSC proliferation, which will help elucidate on the mechanisms controlling the fate decisions in human SSCs.
Adult ; Humans ; Male ; Cell Differentiation ; Cell Proliferation ; Forkhead Transcription Factors/metabolism* ; Spermatogenesis/genetics* ; Spermatogonia/metabolism* ; Stem Cells/metabolism* ; Testis/metabolism*

Mammalian testis exhibits remarkably high transcriptome complexity, and spermatogenesis undergoes two periods of transcriptional cessation. These make the RNA-binding proteins (RBPs) the utmost importance during male germ cell development. Heterogeneous nuclear ribonucleoproteins (hnRNPs) are a large family of RBPs implicated in many steps of RNA processing; however, their roles in spermatogenesis are largely unknown. Here, we investigated the expression pattern of 12 hnRNP family members in mouse testes and found that most detected members are highly expressed in the testis. Furthermore, we found that most of the detected hnRNP proteins (hnRNPD, hnRNPK, hnRNPQ, hnRNPU, and hnRNPUL1) display the highest signals in the nuclei of pachytene spermatocytes, round spermatids, and Sertoli cells, whereas hnRNPE1 exclusively concentrates in the manchette of elongating spermatids. The expression of these hnRNP proteins showed both similarities and specificity, suggesting their diverse roles in spermatogenesis.
Mice ; Male ; Animals ; Heterogeneous-Nuclear Ribonucleoproteins/metabolism* ; Spermatogenesis/genetics* ; Testis/metabolism* ; Spermatids/metabolism* ; Sertoli Cells ; Spermatocytes/metabolism* ; RNA-Binding Proteins/metabolism* ; Mammals

Congenital bilateral absence of the vas deferens (CBAVD) is observed in 1%-2% of males presenting with infertility and is clearly associated with cystic fibrosis transmembrane conductance regulator (CFTR) mutations. CFTR is one of the most well-known genes related to male fertility. The frequency of CFTR mutations or impaired CFTR expression is increased in men with nonobstructive azoospermia (NOA). CFTR mutations are highly polymorphic and have established ethnic specificity. Compared with F508Del in Caucasians, the p.G970D mutation is reported to be the most frequent CFTR mutation in Chinese patients with cystic fibrosis. However, whether p.G970D participates in male infertility remains unknown. Herein, a loss-of-function CFTR p.G970D missense mutation was identified in a patient with CBAVD and NOA. Subsequent retrospective analysis of 122 Chinese patients with CBAVD showed that the mutation is a common pathogenic mutation (4.1%, 5/122), excluding polymorphic sites. Furthermore, we generated model cell lines derived from mouse testes harboring the homozygous Cftr p.G965D mutation equivalent to the CFTR variant in patients. The Cftr p.G965D mutation may be lethal in spermatogonial stem cells and spermatogonia and affect the proliferation of spermatocytes and Sertoli cells. In spermatocyte GC-2(spd)ts (GC2) Cftr p.G965D cells, RNA splicing variants were detected and CFTR expression decreased, which may contribute to the phenotypes associated with impaired spermatogenesis. Thus, this study indicated that the CFTR p.G970D missense mutation might be a pathogenic mutation for CBAVD in Chinese males and associated with impaired spermatogenesis by affecting the proliferation of germ cells.
Humans ; Animals ; Mice ; Male ; Mutation, Missense ; Retrospective Studies ; Cystic Fibrosis Transmembrane Conductance Regulator/genetics* ; Infertility, Male/genetics* ; Mutation ; Vas Deferens/abnormalities* ; Spermatogenesis/genetics*

OBJECTIVE: To study the toxic effects of short-term exposure to gossypol on the testis and kidney in mice and whether these effects are reversible. METHODS: Twenty 7 to 8-week-old male mice were randomized into blank control group, solvent control group, gossypol treatment group and drug withdrawal group. In the former 3 groups, the mice were subjected to daily intragastric administration of 0.3 mL of purified water, 1% sodium carboxymethylcellulose solution, and 30 mg/mL gossypol solution for 14 days, respectively; In the drug withdrawal group, the mice were treated with gossypol solution in the same manner for 14 days followed by treatment with purified water for another 14 days. After the last administration, the mice were euthanized and tissue samples were collected. The testicular tissue was weighed and observed microscopically with HE and PAS staining; the kidney tissue was stained with HE and examined for mitochondrial ATPase activity. RESULTS: Compared with those in the control group, the mice with gossypol exposure showed reduced testicular seminiferous epithelial cells with rounded seminiferous tubules, enlarged space between the seminiferous tubules, interstitium atrophy of the testis, and incomplete differentiation of the spermatogonia. The gossypol-treated mice also presented with complete, non-elongated spermatids, a large number of cells in the state of round spermatids, and negativity for acrosome PAS reaction; diffuse renal mesangial cell hyperplasia, increased mesangial matrix, and adhesion of the mesangium to the wall of the renal capsule were observed, with significantly shrinkage or even absence of the lumens of the renal capsules and reduced kidney mitochondrial ATPase activity. Compared with the gossypol-treated mice, the mice in the drug withdrawal group showed obvious recovery of morphologies of the testis and the kidney, acrosome PAS reaction and mitochondrial ATPase activity. CONCLUSIONS Shortterm treatment with gossypol can cause reproductive toxicity and nephrotoxicity in mice, but these toxic effects can be reversed after drug withdrawal.
Mice ; Male ; Animals ; Gossypol/toxicity* ; Testis ; Seminiferous Tubules ; Spermatids ; Spermatogenesis ; Adenosine Triphosphatases/pharmacology*

The testis is pivotal for male reproduction, and its progressive functional decline in aging is associated with infertility. However, the regulatory mechanism underlying primate testicular aging remains largely elusive. Here, we resolve the aging-related cellular and molecular alterations of primate testicular aging by establishing a single-nucleus transcriptomic atlas. Gene-expression patterns along the spermatogenesis trajectory revealed molecular programs associated with attrition of spermatogonial stem cell reservoir, disturbed meiosis and impaired spermiogenesis along the sequential continuum. Remarkably, Sertoli cell was identified as the cell type most susceptible to aging, given its deeply perturbed age-associated transcriptional profiles. Concomitantly, downregulation of the transcription factor Wilms' Tumor 1 (WT1), essential for Sertoli cell homeostasis, was associated with accelerated cellular senescence, disrupted tight junctions, and a compromised cell identity signature, which altogether may help create a hostile microenvironment for spermatogenesis. Collectively, our study depicts in-depth transcriptomic traits of non-human primate (NHP) testicular aging at single-cell resolution, providing potential diagnostic biomarkers and targets for therapeutic interventions against testicular aging and age-related male reproductive diseases.
Animals ; Male ; Testis ; Sertoli Cells/metabolism* ; Transcriptome ; Spermatogenesis/genetics* ; Primates ; Aging/genetics* ; Stem Cells

Testicular endothelial cells have been found to play an important role in spermatogenesis and fertility, but their mechanism is obscure. Exosomes released by various cells are recognized as cell-cell communication mediators during the initiation and progression of many diseases. Therefore, the current study aimed to investigate the protein and miRNA components of human testicular endothelial cell-derived exosomes (HTEC-Exos) and to explore their potential effects on spermatogenesis. In this study, HTEC-Exos were first isolated by the ultracentrifugation method, and then identified by nanoparticle tracking analysis, transmission electron microscopy (TEM), and western blotting. The characteristics of HTEC-Exos were examined by liquid chromatography-mass spectrometry and microRNA (miRNA) chip analysis. Bioinformatics analysis was performed to explore the potential role of the exosomal content on spermatogenesis. A total of 945 proteins were identified, 11 of which were closely related to spermatogenesis. A total of 2578 miRNAs were identified. Among them, 30 miRNAs demonstrated potential associations with male reproductive disorders, such as azoospermia, and spermatogenesis disorders. In particular, 11 out of these 30 miRNAs have been proven to be involved in spermatogenesis based on available evidence. This study provides a global view of the proteins and miRNAs from HTEC-Exos, suggesting that HTEC-Exos may function as potential effectors during the process of spermatogenesis.
Endothelial Cells ; Exosomes ; Humans ; Male ; MicroRNAs ; Proteomics ; Spermatogenesis

Male infertility has evolved from a common reproductive system disease to a major social issue. Youjing granule (YG) is a Chinese medicinal material used as a therapy method for tonifying the kidneys and removing dampness due to its pathogenic characteristics. YG has been shown to regulate sperm quality in clinical trials, but the underlying mechanism is not fully understood. The present study was aimed to explore the protective effects and mechanism of action of YG on male reproductive system damage caused by methyl methane sulfonate (MMS). We first established an infertility model of rats through oral administration of MMS and then treated with YG. To determine the effect of YG, spermatogenesis, microvascular density, and secretory function of Leydig cells and Sertoli cells in rats were assessed. Spermatogonial stem cells (SSCs) were co-cultured with mouse embryo fibroblast (MEF) cells as an in vitro cell model before exposure to serum containing YG. Furthermore, the proliferation and apoptosis of SSCs were measured. Results indicated that YG increased the expression of self-renewal and proliferation-related molecules such as glial cell line derived neurotrophic factor (GDNF) and fibroblast growth factor-2 (FGF2), and improved the quality of sperm and the proliferation of SSCs. In conclusion, YG may protect spermatogenetic function of rats through regulating the proliferation and self-renewal of SSCs.
Animals ; Cell Proliferation ; Male ; Mice ; Rats ; Semen ; Spermatogenesis ; Spermatogonia ; Stem Cells

Human epididymis protein 4(HE4) is a secretory glycoprotein found in human distal epididymis epithelial cells. It is often used in the early diagnosis, efficacy evaluation and monitoring of ovarian cancer, and also has been considered as an effective serum marker for many other types of cancer. However, its function in the process of sperm maturation is not fully unknown. The maturation of sperm in epididymis is characterized by the acquisition of motility and fertilization. As a member of the whey acid protein (WAP) family, several studies proposed the importance of HE4 in the maturity of sperm in epididymis. This article reviews the effect of HE4 on spermatozoa maturation in epididymis, which provides basis for the evaluation of male reproductive ability, early detection, early diagnosis and pathogenesis of male infertility.
Epididymis/metabolism* ; Humans ; Male ; Semen ; Sperm Maturation ; Sperm Motility ; Spermatozoa/metabolism*

Continuous spermatogenesis depends on the self-renewal and differentiation of spermatogonial stem cells (SSCs). SSCs, the only male reproductive stem cells that transmit genetic material to subsequent generations, possess an inherent self-renewal ability, which allows the maintenance of a steady stem cell pool. SSCs eventually differentiate to produce sperm. However, in an in vitro culture system, SSCs can be induced to differentiate into various types of germ cells. Rodent SSCs are well defined, and a culture system has been successfully established for them. In contrast, available information on the biomolecular markers and a culture system for livestock SSCs is limited. This review summarizes the existing knowledge and research progress regarding mammalian SSCs to determine the mammalian spermatogenic process, the biology and niche of SSCs, the isolation and culture systems of SSCs, and the biomolecular markers and identification of SSCs. This information can be used for the effective utilization of SSCs in reproductive technologies for large livestock animals, enhancement of human male fertility, reproductive medicine, and protection of endangered species.
Adult Germline Stem Cells ; Animals ; Cell Differentiation ; Male ; Spermatogenesis ; Spermatogonia ; Stem Cells

Acephalic spermatozoa syndrome is a rare type of teratozoospermia that severely impairs the reproductive ability of male patients, and genetic defects have been recognized as the main cause of acephalic spermatozoa syndrome. Spermatogenesis and centriole-associated 1 like (SPATC1L) is indispensable for maintaining the integrity of sperm head-to-tail connections in mice, but its roles in human sperm and early embryonic development remain largely unknown. Herein, we conducted whole-exome sequencing (WES) of 22 infertile men with acephalic spermatozoa syndrome. An in silico analysis of the candidate variants was conducted, and WES data analysis was performed using another cohort consisting of 34 patients with acephalic spermatozoa syndrome and 25 control subjects with proven fertility. We identified biallelic mutations in SPATC1L (c.910C>T:p.Arg304Cys and c.994G>T:p.Glu332X) from a patient whose sperm displayed complete acephalia. Both SPATC1L variants are rare and deleterious. SPATC1L is mainly expressed at the head-tail junction of elongating spermatids. Plasmids containing pathogenic variants decreased the level of SPATC1L in vitro. Moreover, none of the patient's four attempts at intracytoplasmic sperm injection (ICSI) resulted in a transplantable embryo, which suggests that SPATC1L defects might affect early embryonic development. In conclusion, this study provides the first identification of SPATC1L as a novel gene for human acephalic spermatozoa syndrome. Furthermore, WES might be applied for patients with acephalic spermatozoa syndrome who exhibit reiterative ICSI failures.
Centrioles/genetics* ; Homozygote ; Humans ; Infertility, Male/genetics* ; Male ; Mutation ; Spermatogenesis/genetics* ; Spermatozoa