Multiple signaling pathways in Sertoli cells: recent findings in spermatogenesis

AMPK regulates immature boar Sertoli cell proliferation through affecting CDK4/Cyclin D3 pathway and mitochondrial function

Sertoli cell (SC) proliferation plays an important role in sperm production and quality; however, the regulatory mechanism of SC proliferation is not well understood. This study investigated the role of adenosine monophosphate-activated protein kinase (AMPK) in the regulation of immature boar SC activity. Cell counting kit-8, Seahorse XFe96, mitochondrial respiratory enzyme-related assay kits, and transmission electron microscopy were used to detect SC proliferative viability, oxygen consumption rate (OCR), mitochondrial respiratory enzyme activity, and the ultrastructure of primary cultured SCs in vitro from the testes of 21-day-old boars. A dual luciferase reporter assay was performed to determine the miRNA-mRNA target interaction. Western blotting was used to analyze cell proliferation-related protein expression of p38, p21, proliferating cell nuclear antigen (PCNA), Cyclin-dependent kinase 4 (CDK4), Cyclin D3, and phosphorylated retinoblastoma protein (Rb). Each experiment had a completely randomized design, with three replicates in each experiment. The results showed that the AMPK inhibitor (Compound C, 20 μM-24 h) increased cell proliferation viability, ATP production, and maximal respiration of SCs by 0.64-, 0.12-, and 0.08-fold (p < 0.05), respectively; increased the SC protein expression of PCNA, CDK4, Cyclin D3, and p-Rb by 0.13-, 0.09-, 0.88-, and 0.12-fold (p < 0.05), respectively; and decreased the SC protein expression of p38 and p21 by 0.36- and 0.27-fold (p < 0.05), respectively. The AMPK agonist AICAR (2 mM-6 h) significantly inhibited SC ultrastructure, OCR, mitochondrial respiratory enzyme activity, and cell proliferation-related protein levels. AMPK was validated to be a target gene of miR-1285 based on the result in which the miR-1285 mimic inhibited the luciferase activity of wild-type AMPK by 0.54-fold (p < 0.001). MiR-1285 mimic promoted the OCR of SCs, with 0.45-, 0.15-, 0.21-, and 0.30-fold (p < 0.01) increases in ATP production, basal and maximal respiration, and spare capacity, respectively. MiR-1285 mimic increased the mitochondrial respiratory enzyme activity of SCs, with 0.63-, 0.70-, and 0.97-fold (p < 0.01) increases in NADH-Q oxidoreductase, cytochrome c oxidase, and ATP synthase, respectively. Moreover, the miR-1285 mimic increased the protein expression of PCNA, CDK4, Cyclin D3, and p-Rb by 0.24-, 0.30-, 0.22-, and 0.13-fold (p < 0.05), respectively, and reduced the protein expression of p38 and p21 by 0.58- and 0.66-fold (p < 0.001). MiR-1285 inhibitor showed opposite effects on the above indicators and induced numerous autophagosomes and large lipid droplets in SCs. A high dose of estradiol (10 μM-6 h, showed a promotion of AMPK activation in a previous study) significantly inhibited SC ultrastructure, mitochondrial function, and proliferation-related pathways, while these adverse effects were weakened by Compound C treatment or miR-1285 mimic transfection. Our findings suggest that the activation and inhibition of AMPK induced by specific drugs or synthesized targeted miRNA fragments could regulate immature boar SC proliferative activity by influencing the CDK4/Cyclin D3 pathway and mitochondrial function; this helps to provide a basis for the prevention and treatment of male sterility in clinical practice.

Oral exposure to phenanthrene during gestation disorders endocrine and spermatogenesis in F1 adult male mice

Phenanthrene (Phe), a typical low-molecular-weight polycyclic aromatic hydrocarbon (PAH) of three benzene rings, is one of the most abundant PAHs detected in daily diets. Pregnant women and infants are at great risk of Phe exposure. In the present study, Phe was administered to pregnant mice at a dose of 0, 60, or 600 μg/kg body weight six times, and the F1 male mice showed significant reproductive disorders: the testicular weight and testis somatic index were significantly reduced; the levels of serum testosterone, GnRH and SHBG were increased, while the FSH levels were reduced; histological analysis showed that the amount of Sertoli cells and primary spermatocytes in seminiferous tubules was increased, while the amount of secondary spermatocytes and spermatids were decreased in Phe groups. The protein levels of PCNA and androgen receptor were reduced. Differently expressed genes in the testis screened by RNA sequence were enriched in antioxidant capacity, reproduction et al.. Further biochemical tests confirmed that the antioxidant capacity in the F1 testis was significantly inhibited by treatment with Phe during pregnancy. Those results suggested that gestational Phe exposure disordered hypothalamic-pituitary-gonadal (HPG) hormones on the one hand, and on the other hand reduced testicular antioxidant capacity and further arrested cell cycle in F1 adult male mice, which co-caused the inhibition of spermatogenesis.

Role of Follicle-stimulating Hormone, Inhibin B, and Anti-Müllerian Hormone in Predicting Sperm Retrieval from Men with Nonobstructive Azoospermia Undergoing Microdissection Testicular Sperm Extraction: A Systematic Review and Meta-analysis

Background and objective

No clear-cut markers for predicting positive sperm retrieval (+SR) at microdissection testicular sperm extraction (mTESE) have been identified thus far. Our aim was to conduct a systematic review and meta-analysis to evaluate the ability of follicle-stimulating hormone (FSH), inhibin B (InhB), and anti-Müllerian hormone (AMH) to predict +SR in men with nonobstructive azoospermia (NOA) undergoing mTESE.

Methods

We performed a search in the PubMed, EMBASE, Web of Science, and Scopus databases according to the Preferred Reporting Items for Systematic Review and Meta-analysis statement. Thirty-four publications were selected for inclusion in the analysis.

Key findings and limitations

Overall, the mean +SR rate was 45%. Pooled standardized mean difference (SMD) values revealed significant hormonal differences between the +SR and -SR groups, with lower FSH (SMD -0.30), higher InhB (SMD 0.54), and lower AMH (SMD -0.56) levels in the +SR group. Pooled odds ratios (Ors) revealed no significant prediction of +SR by either FSH (OR 1.03, 95% confidence interval [CI] 1.00-1.06) or InhB (OR 1.01, 95% CI 1.00-1.02), despite variations in baseline levels and study heterogeneity. Conversely, AMH had significant predictive value (OR 0.82, 95% CI 0.73-0.92), with lower baseline levels in the +SR group. InhB and FSH levels were higher in the +SR group, while InhB exhibited the opposite trend.

Conclusions and clinical implications

Despite study heterogeneity, our meta-analysis findings support the ability of AMH to predict +SR for men with NOA undergoing mTESE.

Patient summary

We conducted a review and analysis of results from previous studies. Our findings show that for men with an infertility condition called nonobstructive azoospermia, blood levels of anti-Müllerian hormone can predict successful extraction of sperm using a microsurgical technique. Levels of two other hormones did not predict successful sperm extraction.

Therapeutic potential of exosomes in spermatogenesis regulation and male infertility

BACKGROUND

Spermatogenesis is a fundamental process crucial for male reproductive health and fertility. Exosomes, small membranous vesicles released by various cell types, have recently garnered attention for their role in intercellular communication.

OBJECTIVE

This review aims to comprehensively explore the role of exosomes in regulating spermatogenesis, focusing on their involvement in testicular development and cell-to-cell communication.

METHODS

A systematic examination of literature was conducted to gather relevant studies elucidating the biogenesis, composition, and functions of exosomes in the context of spermatogenesis.

RESULTS

Exosomes play a pivotal role in orchestrating the complex signaling networks required for proper spermatogenesis. They facilitate the transfer of key regulatory molecules between different cell populations within the testes, including Sertoli cells, Leydig cells, and germ cells.

CONCLUSION

The emerging understanding of exosome-mediated communication sheds light on novel mechanisms underlying spermatogenesis regulation. Further research in this area holds promise for insights into male reproductive health and potential therapeutic interventions.

Evolution of Glutamate Metabolism via GLUD2 Enhances Lactate-Dependent Synaptic Plasticity and Complex Cognition

Human evolution is characterized by rapid brain enlargement and the emergence of unique cognitive abilities. Besides its distinctive cytoarchitectural organization and extensive inter-neuronal connectivity, the human brain is also defined by high rates of synaptic, mainly glutamatergic, transmission, and energy utilization. While these adaptations' origins remain elusive, evolutionary changes occurred in synaptic glutamate metabolism in the common ancestor of humans and apes via the emergence of GLUD2, a gene encoding the human glutamate dehydrogenase 2 (hGDH2) isoenzyme. Driven by positive selection, hGDH2 became adapted to function upon intense excitatory firing, a process central to the long-term strengthening of synaptic connections. It also gained expression in brain astrocytes and cortical pyramidal neurons, including the CA1-CA3 hippocampal cells, neurons crucial to cognition. In mice transgenic for GLUD2, theta-burst-evoked long-term potentiation (LTP) is markedly enhanced in hippocampal CA3-CA1 synapses, with patch-clamp recordings from CA1 pyramidal neurons revealing increased sNMDA receptor currents. D-lactate blocked LTP enhancement, implying that glutamate metabolism via hGDH2 potentiates L-lactate-dependent glia-neuron interaction, a process essential to memory consolidation. The transgenic (Tg) mice exhibited increased dendritic spine density/synaptogenesis in the hippocampus and improved complex cognitive functions. Hence, enhancement of neuron-glia communication, via GLUD2 evolution, likely contributed to human cognitive advancement by potentiating synaptic plasticity and inter-neuronal connectivity.

Neonatal vitamin A supplementation improves sheep fertility potential

This study aimed to explore the effects of neonatal vitamin A (VA) supplementation on testis development and spermatogenesis. A total of 32 newborn lambs were intramuscularly injected with corn oil (control group) or corn oil + 2500 IU/kg BW VA (VA group). They were slaughtered and sampled at 3 weeks and 8 months of age to analyze spermatogenesis, cell proliferation, hormone secretion, antioxidant status of the testis, and adult sheep sperm parameters. Compared with the control group, the expression of spermatogonial differentiation-related genes in VA group was up-regulated (P < 0.05). Testis weight, seminiferous tubule diameter, number of spermatogonium and spermatocyte, and sperm density increased significantly in VA group at 8 months of age (P < 0.05). Neonatal VA injection upregulated the expression of the cell proliferation marker PCNA and cell cycle-related genes in the testis (P < 0.05). VA increased the concentrations of testosterone (T), luteinizing hormone (LH), and follicle-stimulating hormone (FSH) in the serum and upregulated steroidogenesis-related genes in the testis (P < 0.05). The antioxidant levels in the VA group were maintained at high levels. The total antioxidant capacity (T-AOC), antioxidant enzyme content and antioxidant-related genes were increased in the testis (P < 0.05). Furthermore, neonatal VA injection activated retinoic acid (RA) signaling to maintain the blood-testosterone barrier (BTB) in the testis of 3-week-old sheep. AMP-activated protein kinase (AMPK) and protein kinase B (AKT) signaling were also modulated in the sheep testis (P < 0.05). Taken together, VA supplementation in newborn rams promotes testis development and spermatogenesis to improve fertility.

Protective effect of dental pulp stem cells' conditioned medium against cisplatin-induced testicular damage in rats

Cisplatin is a highly effective chemotherapy drug used to treat most solid tumors. However, one of its side effects is testicular toxicity, which can lead to fertility abnormalities. This study investigated the effectiveness of dental pulp mesenchymal stem cells conditioned medium (DPSC-CM) on cisplatin-induced testicular toxicity. In this study, 36 eight-week-old male Wistar rats were randomly divided into three groups equally (n = 12). Group 1 control "CTR", which received normal saline (0.5 ml) intraperitoneally (i.p), group 2 "Cis" which received an intraperitoneal dose of cisplatin (7 mg/kg), and group 3 "Cis+CM" which received an i.p injection of DPSC-CM (0.5 mg/kg) after cisplatin injection. Biochemical, histomorphometric, and histopathological studies were performed on the testis. Our results exhibited that cis administration led to a decline in total body weight, testis weight, diameter, and volume. A decrease in testosterone and IL-6 serum levels, as well as a decrease in IL-6 and TNFα levels, the activity of catalase and SOD enzymes, and an increase in MDA in testicular tissue were detected. Testicular tissue damage was associated with a significant decrease in tube diameter, germinal epithelium height, number of spermatogonia and Sertoli cells, along with a noticeable increase in basement membrane thickness, and perivascular fibrosis. DMSC-CM improved all the mentioned parameters. Taken together, our results demonstrated that DMSC-CM due to its antioxidant and anti-inflammatory properties, could be effective in reversing cisplatin-induced testicular toxicity.

Rreb1 is a key transcription factor in Sertoli cell maturation and function and spermatogenesis in mouse

Spermatogenesis is a developmental process driven by interactions between germ cells and Sertoli cells. This process depends on appropriate gene expression, which might be regulated by transcription factors. This study focused on Rreb1, a zinc finger transcription factor, and explored its function and molecular mechanisms in spermatogenesis in a mouse model. Our results showed that RREB1 was predominantly expressed in the Sertoli cells of the testis. The decreased expression of RREB1 following injection of siRNA caused impaired Sertoli cell development, which was characterized using a defective blood-testis barrier structure and decreased expression of Sertoli cell functional maturity markers; its essential trigger might be SMAD3 destabilization. The decreased expression of RREB1 in mature Sertoli cells influenced the cell structure and function, which resulted in abnormal spermatogenesis, manifested as oligoasthenoteratozoospermia, and we believe RREB1 plays this role by regulating the transcription of Fshr and Wt1. RREB1 has been reported to activate Fshr transcription, and we demonstrated that the knockdown of Rreb1 caused a reduction in follicle-stimulating hormone receptor (FSHR) in the testis, which could be the cause of the increased sperm malformation. Furthermore, we confirmed that RREB1 directly activates Wt1 promoter activity, and RREB1 downregulation induced the decreased expression of Wt1 and its downstream polarity-associated genes Par6b and E-cadherin, which caused increased germ-cell death and reduced sperm number and motility. In conclusion, RREB1 is a key transcription factor essential for Sertoli cell development and function and is required for normal spermatogenesis.

Novel underlying genetic markers for asthenozoospermia due to abnormal spermatogenesis and reproductive organ inflammation

Asthenozoospermia, a male fertility disorder, has a complex and multifactorial etiology. Moreover, the effectiveness of different treatments for asthenozoospermia remains uncertain. Hence, by using bioinformatics techniques, the present study aimed to determine the underlying genetic markers and pathogenetic mechanisms associated with asthenozoospermia due to abnormal spermatogenesis and inflammation of the reproductive tract. GSE160749 dataset was downloaded from the Gene Expression Omnibus database, and the data were filtered to obtain 1336 differentially expressed genes (DEGs) associated with asthenozoospermia. These DEGs were intersected with the epithelial mesenchymal transition datasets to yield 61 candidate DEGs. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses were performed, and the results revealed that these candidate DEGs were significantly enriched in the enzyme-linked receptor pathway and the thyroid hormone pathway. A protein-protein interaction network was constructed to identify the key genes of asthenozoospermia. A total of five key genes were identified, among which SOX9 was significantly upregulated, while HSPA4, SMAD2, HIF1A and GSK3B were significantly downregulated. These findings were validated by conducting reverse transcription-quantitative PCR for clinical semen samples. To determine the underlying molecular mechanisms, a regulatory network of transcription factors and miRNA-mRNA interactions was predicted. The expression levels of HSPA4, SMAD2 and GSK3B were positively associated with several related etiological genes of asthenozoospermia. In total, five key genes were closely associated with the level and type of immune cells; higher levels of activated B cells and CD8 T cells were observed in asthenozoospermia. Thus, the findings of the present study may provide clues to determine the underlying novel diagnostic genetic markers and treatment strategies for asthenozoospermia.

Sox9 downregulation in non-obstructive azoospermia by UTF1 and mediator role of POU5F1

BACKGROUND

Spermatogenesis is the process of producing mature sperm from Spermatogonial stem cells (SSCs) and this process requires a complex cooperation of different types of somatic and germ cells. Undifferentiated spermatogonia initiate the spermatogenesis and Sertoli cells as the only somatic cells inside of the seminiferous tubule play a key role in providing chemical and physical requirements for normal spermatogenesis, here, we investigated the dysfunction of these cells in non-obstructive azoospermia.

MATERIAL AND METHOD

In this study, we analyzed the expression of sox9 and UTF1 in the non-obstructive human testis by immunohistochemistry. Moreover, we used the KEGG pathway and bioinformatics analysis to reveal the connection between our object genes and protein.

RESULTS

The immunohistochemistry analysis of the non-obstructive human seminiferous tubule showed low expression of Sox9 and UTF1 that was detected out of the main location of the responsible cells for these expressions. Our bioinformatics analysis clearly and strongly indicated the relation between UTF1 in undifferentiated spermatogonia and Sox9 in Sertoli cells mediated by POU5F1.

CONCLUSION

Generally, this study showed the negative effect of POU5F1 as a mediator between Sertoli cells as the somatic cells within seminiferous tubules and undifferentiated spermatogonia as the spermatogenesis initiator germ cells in non-obstructive conditions.

Cypermethrin induces Sertoli cell apoptosis through endoplasmic reticulum-mitochondrial coupling involving IP3R1-GRP75-VDAC1

A widely used type II pyrethroid pesticide cypermethrin (CYP) is one of endocrine disrupting chemicals (EDCs) with anti-androgenic activity to induce male reproductive toxicology. However, the mechanisms have not been fully elucidated. This study was to explore the effects of CYP on apoptosis of mouse Sertoli cells (TM4) and the roles of endoplasmic reticulum (ER)-mitochondria coupling involving 1,4,5-trisphosphate receptor type1-glucose-regulated protein 75-voltage-dependent anion channel 1 (IP3R1-GRP75-VDAC1). TM4 were cultured with different concentrations of CYP. Flow cytometry, calcium (Ca2+) fluorescent probe, transmission electron microscopy and confocal microscopy, and western blot were to examine apoptosis of TM4, mitochondrial Ca2+, ER-mitochondria coupling, and expressions of related proteins. CYP was found to increase apoptotic rates of TM4 significantly. CYP was shown to significantly increase expressions of cleaved caspase-3, cleaved poly ADP-ribose polymerase (PARP). Concentration of mitochondrial Ca2+ was increased by CYP treatment significantly. CYP significantly enhanced ER-mitochondria coupling. CYP was shown to increase expressions of IP3R, Grp75 and VDAC1 significantly. We suggest that CYP induces apoptosis in TM4 cells by facilitating mitochondrial Ca2+ overload regulated by ER-mitochondria coupling involving IP3R1-GRP75-VDAC1. This study identifies a novel mechanism of CYP-induced apoptosis in Sertoli cells.

Serum exosomes from hepatitis B virus-infected patients inhibit glycolysis in Sertoli cells via miR-122-5p/ALDOA axis

Hepatitis B virus (HBV) infection is associated with male infertility. The mechanism includes an increase in chromosomal instability in sperm, which has an adverse effect on sperm viability and function. Sertoli cells (SCs) are vital in spermatogenesis because they use glycolysis to provide energy to germ cells and themselves. HBV infection impairs sperm function. However, whether HBV infection disrupts energy metabolism in SCs remains unclear. This study aimed to determine the role of serum exosomes of HBV-infected patients in SC viability and glycolysis. Serum exosomes were obtained from 30 patients with (HBV+_exo) or without (HBV-_exo) HBV infection using high-speed centrifugation and identified by transmission electron microscopy and western blot analysis. Cell viability is determined by CCK-8 assay. Glycolysis is determined by detecting extracellular acidification rate and ATP levels. miR-122-5p expression levels are detected by quantitative RT-PCR, and a dual-luciferase gene reporter assay confirms the downstream target gene of miR-122-5p. Protein expression is determined by western blot analysis. The results show that HBV+ _exo inhibited cell viability, extracellular acidification rate, and ATP production of SCs. miR-122-5p is highly expressed in HBV+ _exo compared with that in HBV-_exo. Furthermore, HBV+ _exo is efficiently taken up by SCs, whereas miR-122-5p is efficiently transported to SCs. miR-122-5p overexpression downregulates ALDOA expression and inhibits SC viability and glycolysis. However, ALDOA overexpression reverses the effects of miR-122-5p and HBV+ _exo on SC viability and glycolysis. HBV+ _exo may deliver miR-122-5p to target ALDOA and inhibit SC viability and glycolysis, thus providing new therapeutic ideas for treating HBV-associated male infertility.

MAPKs signaling is obligatory for male reproductive function in a development-specific manner

Mitogen-activated protein kinases (MAPKs) represent widely expressed and evolutionarily conserved proteins crucial for governing signaling pathways and playing essential roles in mammalian male reproductive processes. These proteins facilitate the transmission of signals through phosphorylation cascades, regulating diverse intracellular functions encompassing germ cell development in testis, physiological maturation of spermatozoa within the epididymis, and motility regulation at ejaculation in the female reproductive tract. The conservation of these mechanisms appears prevalent across species, including humans, mice, and, to a limited extent, livestock species such as bovines. In Sertoli cells (SCs), MAPK signaling not only regulates the proliferation of immature SCs but also determines the appropriate number of SCs in the testes at puberty, thereby maintaining male fertility by ensuring the capacity for sperm cell production. In germ cells, MAPKs play a crucial role in dynamically regulating testicular cell-cell junctions, supporting germ cell proliferation and differentiation. Throughout spermatogenesis, MAPK signaling ensures the appropriate Sertoli-to-germ cell ratio by regulating apoptosis, controlling the metabolism of developing germ cells, and facilitating the maturation of spermatozoa within the cauda epididymis. During ejaculation in the female reproductive tract, MAPKs regulate two pivotal events-capacitation and the acrosome reaction essential for maintaining the fertility potential of sperm cells. Any disruptions in MAPK pathway signaling possibly may disturb the testicular microenvironment homeostasis, sperm physiology in the male body before ejaculation and in the female reproductive tract during fertilization, ultimately compromising male fertility. Despite decades of research, the physiological function of MAPK pathways in male reproductive health remains inadequately understood. The current review attempts to combine recent findings to elucidate the impact of MAPK signaling on male fertility and proposes future directions to enhance our understanding of male reproductive functions.

Inhibition of miR-143-3p Restores Blood-Testis Barrier Function and Ameliorates Sertoli Cell Senescence

Due to the increasing trend of delayed childbirth, the age-related decline in male reproductive function has become a widely recognized issue. Sertoli cells (SCs) play a vital role in creating the necessary microenvironment for spermatogenesis in the testis. However, the mechanism underlying Sertoli cell aging is still unclear. In this study, senescent Sertoli cells showed a substantial upregulation of miR-143-3p expression. miR-143-3p was found to limit Sertoli cell proliferation, promote cellular senescence, and cause blood-testis barrier (BTB) dysfunction by targeting ubiquitin-conjugating enzyme E2 E3 (UBE2E3). Additionally, the TGF-β receptor inhibitor SB431542 showed potential in alleviating age-related BTB dysfunction, rescuing testicular atrophy, and reversing the reduction in germ cell numbers by negatively regulating miR-143-3p. These findings clarified the regulatory pathways underlying Sertoli cell senescence and suggested a promising therapeutic approach to restore BTB function, alleviate Sertoli cell senescence, and improve reproductive outcomes for individuals facing fertility challenges.

The miR-34b/MEK/ERK pathway is regulated by NR5A1 and promotes differentiation in primary bovine Sertoli cells

Sertoli cells play a key role in testicular development and spermatogenesis. It has been suggested that Sertoli cells differentiate after their proliferation ceases. Our previous study showed that miR-34b inhibits proliferation by targeting MAP2K1 mediated MEK/ERK signaling pathway in bovine immature Sertoli cells. Subsequent studies have revealed that the differentiation marker androgen receptor is upregulated during this process. However, the effect of the miR-34b/MEK/ERK pathway on immature bovine Sertoli cell differentiation and the underlying molecular mechanisms are yet to be explored. In this study, we determined that the miR-34b/MEK/ERK pathway was involved in the differentiation of primary Sertoli cells (PSCs) in response to retinoic acid. Transfection of an miR-34b mimic into PSCs promoted cell differentiation, whereas transfection of an miR-34b inhibitor into PSCs delayed it. Pharmacological inhibition of MEK/ERK signaling by AZD6244 promoted PSCs differentiation. Mechanistically, miR-34b promoted PSCs differentiation by inhibiting the MEK/ERK signaling pathway. Through a combination of bioinformatics analysis, dual-luciferase reporter assay, quantitative real-time PCR, and western blotting, nuclear receptor subfamily 5 group A member 1 (NR5A1) was identified as an upstream negative transcription factor of miR-34b. Furthermore, NR5A1 knockdown promoted Sertoli cell differentiation, whereas NR5A1 overexpression had the opposite effect. Together, this study revealed a new NR5A1/miR-34b/MEK/ERK axis that plays a significant role in Sertoli cell differentiation and provides a theoretical and experimental framework for further clarifying the regulation of cell differentiation in bovine PSCs.

Integration of RRBS and RNA-seq unravels the regulatory role of DNMT3A in porcine Sertoli cell proliferation

DNMT3A participates in de novo methylation, yet its impact on the proliferation of testicular Sertoli cells remains unclear. Development-specific methylation has been proven to be associated with cellular development. Therefore, in this study, we simulated DNMT3A expression pattern during testicular development by DNMT3A interference. Then, RRBS and RNA-seq were used to decipher DNMT3A regulatory mechanisms on Sertoli cell proliferation. Immunofluorescence staining revealed the expression of DNMT3A in the Sertoli cells of the prepubertal testis. DNMT3A was demonstrated to inhibit the cell cycle and proliferation of Sertoli cells, while promoting cell apoptosis. After transfected with DNMT3A interference, a total of 560 DEGs and 2,091 DMGs produced by DNMT3A interference were identified between two treated groups, respectively. Integrating the results from RRBS and RNA-seq, the overlapping genes between DMGs and DEGs were found to be enriched in the Gene Ontology (GO) terms related to cellular development and the Apelin signaling pathway. The present study demonstrated the impact of DNMT3A on the proliferation of porcine testicular Sertoli cells, suggesting that DNMT3A primarily acts through the Apelin signaling pathway. These findings provide valuable insights into how DNMT3A influences testicular development and health, offering new perspectives.

Comprehensive analyses of 435 goat transcriptomes provides insight into male reproduction

A systematic analysis of genes related to reproduction is crucial for obtaining a comprehensive understanding of the molecular mechanisms that underlie male reproductive traits in mammals. Here, we utilized 435 goat transcriptome datasets to unveil the testicular tissue-specific genes (TSGs), allele-specific expression (ASE) genes and their uncharacterized transcriptional features related to male goat reproduction. Results showed a total of 1790 TSGs were identified in goat testis, which was the most among all tissues. GO enrichment analyses suggested that testicular TSGs were mainly involved in spermatogenesis, multicellular organism development, spermatid development, and flagellated sperm motility. Subsequently, a total of 95 highly conserved TSGs (HCTSGs), 508 middle conserved TSGs (MCTSGs) and 42 no conserved TSGs (NCTSGs) were identified in goat testis. GO enrichment analyses suggested that the HCTSGs and MCTSGs has a more important association with male reproduction than NCTSGs. Additionally, we identified 644 ASE genes, including 88 tissue-specific ASE (TS-ASE) genes (e.g., FSIP2, TDRD9). GO enrichment analyses indicated that both ASE genes and TS-ASE genes were associated with goat male reproduction. Overall, this study revealed an extensive gene set involved in the regulation of male goat reproduction and their dynamic transcription patterns. Data reported here provide valuable insights for a further improvement of the economic benefits of goats as well as future treatments for male infertility.

Tissue engineering studies in male infertility disorder

Infertility is an important issue among couples worldwide which is caused by a variety of complex diseases. Male infertility is a problem in 7% of all men. In vitro spermatogenesis (IVS) is the experimental approach that has been developed for mimicking seminiferous tubules-like functional structures in vitro. Currently, various researchers are interested in finding and developing a microenvironmental condition or a bioartificial testis applied for fertility restoration via gamete production in vitro. The tissue engineering (TE) has developed new approaches to treat male fertility preservation through development of functional male germ cells. This makes TE a possible future strategy for restoration of male fertility. Although 3D culture systems supply the perception of the effect of cellular interactions in the process of spermatogenesis, formation of a native gradient of autocrine/paracrine factors in 3D culture systems have not been considered. These results collectively suggest that maintaining the microenvironment of testicular cells even in the form of a 3D-culture system is crucial in achieving spermatogenesis ex vivo. It is also possible to engineer the testicular structures using biomaterials to provide a supporting scaffold for somatic and stem cells. The insemination of these cells with GFs is possible for temporally and spatially adjusted release to mimic the microenvironment of the in situ seminiferous epithelium. This review focuses on recent studies and advances in the application of TE strategies to cell-tissue culture on synthetic or natural scaffolds supplemented with growth factors.

Coordinated alternation of DNA methylation and alternative splicing of PBRM1 affect bovine sperm structure and motility

DNA methylation and gene alternative splicing drive spermatogenesis. In screening DNA methylation markers and transcripts related to sperm motility, semen from three pairs of full-sibling Holstein bulls with high and low motility was subjected to reduced representation bisulphite sequencing. A total of 948 DMRs were found in 874 genes (gDMRs). Approximately 89% of gDMR-related genes harboured alternative splicing events, including SMAD2, KIF17, and PBRM1. One DMR in exon 29 of PBRM1 with the highest 5mC ratio was found, and hypermethylation in this region was related to bull sperm motility. Furthermore, alternative splicing events at exon 29 of PBRM1 were found in bull testis, including PBRM1-complete, PBRM1-SV1 (exon 28 deletion), and PBRM1-SV2 (exons 28-29 deletion). PBRM1-SV2 exhibited significantly higher expression in adult bull testes than in newborn bull testes. In addition, PBRM1 was localized to the redundant nuclear membrane of bull sperm, which might be related to sperm motility caused by sperm tail breakage. Therefore, the hypermethylation of exon 29 may be associated with the production of PBRM1-SV2 in spermatogenesis. These findings indicated that DNA methylation alteration at specific loci could regulate gene splicing and expression and synergistically alter sperm structure and motility.

Nitric oxide synthase and its function in animal reproduction: an update

Nitric oxide (NO), a free radical labile gas, is involved in the regulation of various biological functions and physiological processes during animal reproduction. Recently, increasing evidence suggests that the biological role and chemical fate of NO is dependent on dynamic regulation of its biosynthetic enzyme, three distinct nitric oxide synthase (NOS) according to their structure, location and function. The impact of NOS isoforms on reproductive functions need to be timely elucidated. Here, we focus on and the basic background and latest studies on the development, structure, importance inhibitor, location pattern, complex functions. Moreover, we summarize the exactly mechanisms which involved some cell signal pathways in the regulation of NOS with cellular and molecular level in the animal reproduction. Therefore, this growing research area provides the new insight into the important role of NOS male and female reproduction system. It also provides the treatment evidence on targeting NOS of reproductive regulation and diseases.

Altered microRNA expression profiles of human spermatozoa in normal fertile men of different ages

MicroRNAs (miRNAs) are mediators of the aging process. The purpose of this work was to analyze the miRNA expression profiles of spermatozoa from men of different ages with normal fertility. Twenty-seven donors were divided into three groups by age (Group A, n = 8, age: 20-30 years; Group B, n = 10, age: 31-40 years; and Group C, n = 9, age: 41-55 years) for high-throughput sequencing analysis. Samples from 65 individuals (22, 22, and 21 in Groups A, B, and C, respectively) were used for validation by quantitative real-time polymerase chain reaction (qRT-PCR). A total of 2160 miRNAs were detected: 1223 were known, 937 were newly discovered and unnamed, of which 191 were expressed in all donors. A total of 7, 5, and 17 differentially expressed microRNAs (DEMs) were found in Group A vs B, Group B vs C, and Group A vs C comparisons, respectively. Twenty-two miRNAs were statistically correlated with age. Twelve miRNAs were identified as age-associated miRNAs, including hsa-miR-127-3p, mmu-miR-5100_L+2R-1, efu-miR-9226_L-2_1ss22GA, cgr-miR-1260_L+1, hsa-miR-652-3p_R+1, pal-miR-9993a-3p_L+2R-1, hsa-miR-7977_1ss6AG, hsa-miR-106b-3p_R-1, hsa-miR-186-5p, PC-3p-59611_111, hsa-miR-93-3p_R+1, and aeca-mir-8986a-p5_1ss1GA. There were 9165 target genes of age-associated miRNAs. Gene Ontology (GO) analysis of the target genes identified revealed enrichment of protein binding, membrane, cell cycle, and so on. The Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis of age-related miRNAs for target genes revealed 139 enriched pathways, such as signaling pathways regulating stem cell pluripotency, metabolic pathways, and the Hippo signaling pathway. This suggests that miRNAs play a key role in male fertility changes with increasing age and provides new evidence for the study of the mechanism of age-related male fertility decline.

Unveiling the Genetic Complexity of Teratozoospermia: Integrated Genomic Analysis Reveals Novel Insights into lncRNAs' Role in Male Infertility

Male infertility is a global health issue, affecting over 20 million men worldwide. Genetic factors are crucial in various male infertility forms, including teratozoospermia. Nonetheless, the genetic causes of male infertility remain largely unexplored. In this study, we employed whole-genome sequencing and RNA expression analysis to detect differentially expressed (DE) long-noncoding RNAs (lncRNAs) in teratozoospermia, along with mutations that are exclusive to teratozoospermic individuals within these DE lncRNAs regions. Bioinformatic tools were used to assess variants' impact on lncRNA structure, function, and lncRNA-miRNA interactions. Our analysis identified 1166 unique mutations in teratozoospermic men within DE lncRNAs, distinguishing them from normozoospermic men. Among these, 64 variants in 23 lncRNAs showed potential regulatory roles, 7 variants affected 4 lncRNA structures, while 37 variants in 17 lncRNAs caused miRNA target loss or gain. Pathway Enrichment and Gene Ontology analyses of the genes targeted by the affected miRNAs revealed dysregulated pathways in teratozoospermia and a link between male infertility and cancer. This study lists novel variants and lncRNAs associated for the first time with teratozoospermia. These findings pave the way for future studies aiming to enhance diagnosis and therapy in the field of male infertility.

TAM receptors in phagocytosis: Beyond the mere internalization of particles

TYRO3, AXL, and MERTK constitute the TAM family of receptor tyrosine kinases, activated by their ligands GAS6 and PROS1. TAMs are necessary for adult homeostasis in the immune, nervous, reproductive, skeletal, and vascular systems. Among additional cellular functions employed by TAMs, phagocytosis is central for tissue health. TAM receptors are dominant in providing phagocytes with the molecular machinery necessary to engulf diverse targets, including apoptotic cells, myelin debris, and portions of live cells in a phosphatidylserine-dependent manner. Simultaneously, TAMs drive the release of anti-inflammatory and tissue repair molecules. Disruption of the TAM-driven phagocytic pathway has detrimental consequences, resulting in autoimmunity, male infertility, blindness, and disrupted vascular integrity, and which is thought to contribute to neurodegenerative diseases. Although structurally and functionally redundant, the TAM receptors and ligands underlie complex signaling cascades, of which several key aspects are yet to be elucidated. We discuss similarities and differences between TAMs and other phagocytic pathways, highlight future directions and how TAMs can be harnessed therapeutically to modulate phagocytosis.

The Regulatory Effects of JAK2/STAT3 on Spermatogenesis and the Redox Keap1/Nrf2 Axis in an Animal Model of Testicular Ischemia Reperfusion Injury

The male reproductive system requires the pleiotropic activity of JAK/STAT to maintain its function, especially spermatogenesis. The study aims to investigate the effect of JAK2 signaling on the expression of the Keap1/Nrf2 axis, spermatogenesis, and the Sertoli cells (Sc) junctions in an animal model of testicular ischemia reperfusion injury (tIRI). Testes subjected to tIRI exhibited increased JAK2/STAT3 activity associated with spermatogenic arrest and reduced expression of the Sc junctions. In addition, there was an increased protein expression of Keap1 and decreased Nrf2., which was coupled with the downregulation of gene expression of antioxidant enzymes. Reduced SOD and CAT activities were accompanied by increased lipid peroxidation and protein carbonylation during tIRI. Increased caspase 9 activity and Bax/Bcl2 ratio indicated initiation of apoptosis. Inhibition of JAK2 activity by AG490 maintained the integrity of spermatogenesis and SC junctions, normalized the expression of the Keap1/Nrf2 axis and its downstream antioxidant enzymes, and prevented germ cell apoptosis. The results further emphasized the regulatory role of JAK2/STAT3 on spermatogenesis, Keap1/Nrf2 signaling, and maintenance of the testicular redox balance to combat testicular dysfunction and male infertility.

M6A transcriptome-wide map of circRNAs identified in the testis of normal and AZ-treated Xenopus laevis

BACKGROUND

Evidence showed that N6-methyladenosine (m6A) is strongly associated with male germline development. However, the role of m6A methylation on circRNAs in amphibians remains unknown. In this study, we conducted m6A sequencing analysis to explore the m6A transcriptome-wide profile of circRNAs in testis tissues of Xenopus laevis (X. laevis) with and without treatment with 100 µg/L atrazine (AZ).

RESULTS

The analysis showed that m6A modification of circRNAs enriched in sense overlapping in testes of X. laevis. We identified the differential m6A modification sites within circRNAs in testes of AZ-exposed X. laevis and compared that with animals from control group. The results showed that a total of 1507 methylated m6A sites was induced by AZ (760 up-methylated and 747 down-methylated). The cross-analysis exhibited a negative correlation of differentially methylated m6A peaks and circRNAs expression level. The Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis indicated that 20 key pathways may be involved in the mechanism of testis damage of AZ-exposed X. laevis.

CONCLUSIONS

These findings indicated that differentially m6A-methylated circRNAs may play important roles in abnormal testis development of AZ-exposed X. laevis. This study is the first report about a map of m6A modification of circRNAs in male X. laevis and provides a basis for further studying on the function and mechanism of m6A methylation of circRNAs in the testis development of amphibian.

Gastrodin protects porcine sertoli cells from zearalenone-induced abnormal secretion of glial cell line-derived neurotrophic factor through the NOTCH signaling pathway

Zearalenone (ZEA) is a prevalent mycotoxin found in moldy diets and is associated with reproductive dysfunction. However, the molecular underpinning of ZEA in impairment of spermatogenesis remains largely unknown. To unveil the toxic mechanism of ZEA, we established a co-culture model using porcine Sertoli cells and porcine spermatogonial stem cells (pSSCs) to investigate the impact of ZEA on these cell types and their associated signaling pathways. Our findings showed that low concentration of ZEA inhibited cell apoptosis, while high concentration induced cell apoptosis. Furthermore, the expression levels of Wilms' tumor 1 (WT1), proliferating cell nuclear antigen (PCNA) and glial cell line-derived neurotrophic factor (GDNF) were significantly decreased in ZEA treatment group, while concurrently upregulating the transcriptional levels of the NOTCH signaling pathway target genes HES1 and HEY1. The addition of the NOTCH signaling pathway inhibitor DAPT (GSI-IX) alleviated the damage to porcine Sertoli cells caused by ZEA. Gastrodin (GAS) significantly increased the expression levels of WT1, PCNA and GDNF, and inhibited the transcription of HES1 and HEY1. GAS also efficiently restored the decreased expression levels of DDX4, PCNA and PGP9.5 in co-cultured pSSCs suggesting its potential in ameliorating the damage caused by ZEA to Sertoli cells and pSSCs. In conclusion, the present study demonstrates that ZEA disrupts pSSCs self-renewal by affecting the function of porcine Sertoli cell, and highlights the protective mechanism of GAS through the regulation of the NOTCH signaling pathway. These findings may offer a novel strategy for alleviating ZEA-induced male reproductive dysfunction in animal production.

Do macrophages play a role in the adverse effects of endocrine disrupting chemicals (EDCs) on testicular functions?

During the past decades, several endocrine disrupting chemicals (EDCs) have been confirmed to affect male reproductive function and fertility in animal studies. EDCs are suspected to exert similar effects in humans, based on strong associations between levels of antiandrogenic EDCs in pregnant women and adverse reproductive effects in infants. Testicular macrophages (tMΦ) play a vital role in modulating immunological privilege and maintaining normal testicular homeostasis as well as fetal development. Although tMΦ were not historically studied in the context of endocrine disruption, they have emerged as potential targets to consider due to their critical role in regulating cells such as spermatogonial stem cells (SSCs) and Leydig cells. Few studies have examined the impact of EDCs on the ability of testicular cells to communicate and regulate each other's functions. In this review, we recapitulate what is known about tMΦ functions and interactions with other cell types in the testis that support spermatogenesis and steroidogenesis. We also surveyed the literature for reports on the effects of the EDCs genistein and DEHP on tMΦ, SSCs, Sertoli and Leydig cells. Our goal is to explore the possibility that EDC disruption of tMΦ interactions with other cell types may play a role in their adverse effects on testicular developmental programming and functions. This approach will highlight gaps of knowledge, which, once resolved, should improve the risk assessment of EDC exposure and the development of safeguards to protect male reproductive functions.

The role of death receptor signaling pathways in mouse Sertoli cell avoidance of apoptosis during LPS- and IL-18-induced inflammatory conditions

Lipopolysaccharide (LPS) triggers infectious acute inflammation, and interleukin (IL)-18 is an inflammasome-mediated cytokine. We previously demonstrated that endogenous IL-18 induces testicular germ cell apoptosis during acute inflammation when plasma IL-18 levels are high. Additionally, high-dose recombinant IL-18 (rIL-18) induced Leydig cell apoptosis. The blood-testis barrier formed by Sertoli cells protects testicular germ cells from both exogenous and endogenous harmful substances. However, the impact of LPS and IL-18 on Sertoli cells remained unclear. We stimulated TM4 cells, a mouse Sertoli cell line, with LPS (200 or 1000 ng/mL) or rIL-18 (0.1-100 ng/mL) at levels that induced Leydig cell apoptosis in our previous study and assessed caspase 3 cleavage and the mRNA expression of inflammatory cytokines and markers of apoptotic pathways (Tnfr1, Fasl, Fas, Fadd) after stimulation. Il6 mRNA was increased by LPS stimulation. Tnfα mRNA was increased by 200 ng/mL LPS but not 1000 ng/mL LPS. Fas was increased, but Fasl was decreased, by LPS. LPS had little influence on Tnfr1 or Fadd mRNA expression and did not induce apoptosis. Il18 mRNA was not increased, and Il18r1 was significantly decreased following LPS treatment. Treatment with rIL-18 increased Il18r1 mRNA and induced inflammation, but decreased Tnfr1 and had little influence on apoptosis, as indicated by Tnfα, Fasl, Fas, Fadd and cleaved caspase 3. These results suggested that Sertoli cells do not easily undergo apoptosis despite strong inflammatory stimuli. Additionally, Sertoli cells may resist inflammation and play a larger role in protecting testicular homeostasis than other component cells of the testis.

Aflatoxin B1 disrupts testicular development via the cell cycle-related Ras/PI3K/Akt signaling in mice and pig

Aflatoxins B1 (AFB1), a type I carcinogen widely present in the environment, not only poses a danger to animal husbandry, but also poses a potential threat to human reproductive health, but its mechanism is still unclear. To address this question, multi-omics were performed on porcine Sertoli cells and mice testis. The data suggest that AFB1 induced testicular damage manifested as decreased expression of GJA1, ZO1 and OCCLUDIN in mice (p < 0.01) and inhibition of porcine Sertoli cell proliferation. Transcriptomic analysis suggested changes in noncoding RNA expression profiles that affect the cell cycle-related Ras/PI3K/Akt signaling pathway after AFB1 exposure both in mice and pigs. Specifically, AFB1 caused abnormal cell cycle of testis with the characterization of decreased expressions of CCNA1, CCNB1 and CDK1 (p < 0.01). Flow cytometry revealed that the G2/M phase was significantly increased after AFB1 exposure. Meanwhile, AFB1 downregulated the expressions of Ras, PI3K and AKT both in porcine Sertoli cell (p < 0.01) and mice testis (p < 0.01). Metabolome analysis verified the alterations in the PI3K/Akt signaling pathway (p < 0.05). Moreover, the joint analysis of metabolome and microbiome found that the changes of metabolites were correlated with the expression of flora. In conclusion, we have demonstrated that AFB1 impairs testicular development via the cell cycle-related Ras/PI3K/Akt signaling.

Loss of PMFBP1 Disturbs Mouse Spermatogenesis by Downregulating HDAC3 Expression

PURPOSE

Polyamine modulating factor 1 binding protein (PMFBP1) acts as a scaffold protein for the maintenance of sperm structure. The aim of this study was further to identify the new role and molecular mechanism of PMFBP1 during mouse spermatogenesis.

METHODS AND RESULTS

We identified a profile of proteins interacting with PMFBP1 by immunoprecipitation combined with mass spectrometry and demonstrated that class I histone deacetylases, particularly HDAC3 and chaperonin-containing TCP1 subunit 3 (CCT3), were potential interaction partners of PMFBP1 based on network analysis of protein-protein interactions and co-immunoprecipitation. Immunoblotting and immunochemistry assays showed that loss of Pmfbp1 would result in a decline in HDACs and change the proteomic profile of mouse testis, in which differently expressed proteins are associated with spermatogenesis and assembly of flagella, which was proved by proteomic analysis of testis tissue obtained from Pmfbp1^-/- mice. After integrating with transcriptome data for Hdac3^-/- and Sox30^-/- round sperm obtained from a public database, RT-qPCR confirmed ring finger protein 151 (Rnf151) and ring finger protein 133 (Rnf133) were key downstream response factors of the Pmfbp1-Hdac axis affecting mouse spermatogenesis.

CONCLUSION

Taken together, this study indicates a previously unidentified molecular mechanism of PMFBP1 in spermatogenesis whereby PMFBP1 interacts with CCT3, affecting the expression of HDAC3, followed by the downregulation of RNF151 and RNF133, resulting in an abnormal phenotype of sperm beyond the headless sperm tails. These findings not only advance our understanding of the function of Pmfbp1 in mouse spermatogenesis but also provide a typical case for multi-omics analysis used in the functional annotation of specific genes.

Dysregulation of Immature Sertoli Cell Functions by Exposure to Acetaminophen and Genistein in Rodent Cell Models

Sertoli cells are essential for germ cell development and function. Their disruption by endocrine disrupting chemicals (EDCs) or drugs could jeopardize spermatogenesis, contributing to male infertility. Perinatal exposure to EDCs and acetaminophen (APAP) disrupts male reproductive functions in animals and humans. Infants can be exposed simultaneously to the dietary soy phytoestrogen genistein (GEN) and APAP used for fever or pain relief. Our goal was to determine the effects of 10-100 µM APAP and GEN, alone or mixed, on immature Sertoli cells using mouse TM4 Sertoli cell line and postnatal-day 8 rat Sertoli cells, by measuring cell viability, proliferation, prostaglandins, genes and protein expression, and functional pathways. A value of 50 µM APAP decreased the viability, while 100 µM APAP and GEN decreased the proliferation. Sertoli cell and eicosanoid pathway genes were affected by GEN and mixtures, with downregulation of Sox9, Cox1, Cox2, and genes relevant for Sertoli cell function, while genes involved in inflammation were increased. RNA-seq analysis identified p53 and TNF signaling pathways as common targets of GEN and GEN mixture in both cell types. These results suggest that APAP and GEN dysregulate immature Sertoli cell function and may aid in elucidating novel EDC and drug targets contributing to the etiology of male infertility.

Sox2 Localization During Spermatogenesis and Its Association with other Spermatogenesis Markers Using Protein-Protein Network Analysis

Background

Sox2 (SRY box2) is an essential transcription factor that plays a vital role in spermatogenesis and regulates the genes in this process. Sox2 is important for pluripotency, self-renewal, and even spermatogonial stem cell differentiation. This gene is found in pluripotent and specialized cells, and it is involved in their biological activities.

Methods

Protein-protein interaction (PPI) network analysis was performed during spermatogenesis using NCBI, STRING, and Cytoscape databases. Then, after isolating spermatogonial stem cells from 6 C57BL/6 mice, mouse embryonic stem cells and ES-like cells were prepared. In the following, Sox2 expression was examined in differentiated and undifferentiated spermatogonia by immunohistochemistry (IMH), immunocytochemistry (ICC), and Fluidigm PCR (polymerase chain reaction). Finally, the results were compared using the Kruskal-Wallis and Dunn tests at the significance level of p<0.05.

Results

The results of this experiment showed that contrary to expectations, Sox2 has cytoplasmic expression in undifferentiated cells and nuclear expression in differentiated cells in in vitro conditions. In addition, the expression of Sox2 increased during differentiation. Fluidigm PCR showed a significantly higher expression of Sox2 (p<0.05) in differentiated compared to undifferentiated spermatogonia. Sox2 has an interaction with other genes during spermatogenesis such as Oct4, Nanog, Klf4, Stra8, Smad1, Tcf3, and Osm.

Conclusion

Sox2, which is known as a pluripotency marker, has a vital role in spermatogenesis and could be a differential marker. Sox2 has strong connections with other genes such as Oct4, Nanog, Klf4, Tcf3, Osm, Stra8, Lim2, Smad1, Gdnf, and Kit.

Male Reproductive Tract Involvement and Sperm Parameters in SARS-CoV-2 Patients: A Systematic Review and Meta-Analysis

PURPOSE

There is a growing concern regarding the impact of SARS-CoV-2 infection on the male reproductive tract due to ACE2 receptor expression, however, its impact remains unclear. We performed this review to evaluate whether SARS-CoV-2 infection affects the male reproductive system.

MATERIALS AND METHODS

We conducted a search in the Embase, Scopus, and MEDLINE databases, adhering to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guideline. Eligible studies comprised articles reporting viral RNA presence in semen, sperm parameters, and orchitis or orchiepididymitis occurrence in SARS-CoV-2 patients. Observational studies' quality was determined using the Newcastle-Ottawa Scale (NOS). Case reports were assessed using the Joanna Briggs Institute (JBI)'s checklist.

RESULTS

A total of 32 relevant articles were included. Viral RNA was found in 7% of infected patients' semen (95% CI, -0.01 to 0.15) from 3 studies. There were also only 7% of patients with orchitis or orchiepididymitis clinical manifestations (95% CI, 0.05-0.10). The semen volume and concentration were 2.34 mL (95% CI, 1.87-2.81) and 51.73 million/mL (95% CI, 31.60-71.85). The progressive and total motility percentages were 36.11% (95% CI, 28.87-43.35) and 43.07% (95% CI, 28.57-57.57), respectively. The morphology was 6.03% (95% CI, -1.05 to 13.10). There is a difference in semen volume between moderate and severe infections (MD, 0.52; 95% CI, 0.27-0.76; p<0.0001) and concentration between mild and moderate (MD, 18.74; 95% CI, 1.02-36.46; p=0.04), mild and severe (MD, 43.50; 95% CI, 13.86-73.14; p=0.004), as well as moderate and severe (MD, 22.25; 95% CI, 9.33-35.17; p=0.0007).

CONCLUSIONS

SARS-CoV-2 infection may result in decreased sperm concentration in severe cases and the mechanism relates to potential reproductive tract inflammation. The absence of large viral RNA detection in the semen indicates a systemic effect, although this is largely unproven.

Comparative analysis of microRNA and messengerRNA expression profiles in plateau zokor testicular cells under reproductive suppression

Introduction

Reproductive suppression is an adaptive strategy that affects the success rate and reproductive efficiency in animals, which in turn affects population continuation and evolution. However, no studies on the miRNAs in testicular development and spermatogenesis regulatory mechanisms under reproductive suppression have been reported.

Methods

In this study, the differentially expressed (DE) miRNAs, miRNA-mRNA interaction network and function of the plateau zokor testicular cells of non-breeders and breeders during the breeding season were comprehensively analyzed by transcriptomics.

Results

In total, 381 known and 94 novel miRNAs were determined. Compared with that in the breeders, 70 downregulated and 68 upregulated DE miRNAs were identified in the non-breeders. We predicted 1670 significant target mRNAs by analyzing the miRNA and mRNA expression profiles. According to the miRNA-mRNA interaction network, the target mRNAs of the DE miRNAs were related to testicular development and spermatogenesis. GO indicate that the target mRNAs were related to testicular development and spermatogenesis. KEGG indicate that pathways of target mRNAs enrichment related to testicular development, spermatogenesis, and energy metabolism. PROK2 was determined as the target mRNA of rno-miR-143-3p.

Discussion

Our study offers a basis for the regulatory mechanisms of miRNAs in testicular development and spermatogenesis in plateau zokor under reproductive suppression and offers a reference for reproductive regulation.

Seasonal spermatogenesis in the red-eared slider (Trachemys scripta elegans): The roles of GnRH, actin cytoskeleton, and MAPK

Reproduction is the key to the ecological invasion of alien species. As an invasive species, the characteristic and regularity of red-eared slider (Trachemys scripta elegans) spermatogenesis is an index for evaluating reproduction and ecological adaptation. Here, we investigated the characteristics of spermatogenesis i.e., the gonadosomatic index (GSI), plasma reproductive hormone levels, and the histological structure of testes by HE and TUNEL staining, and then RNA-Seq in T. s. elegans. The histomorphological evidence confirmed that seasonal spermatogenesis in T. s. elegans has four successive phases: quiescence (December-May of the following year), early-stage (June-July), mid-stage (August-September), and late-stage (October-November). In contrast to 17β-estradiol, testosterone levels were higher during quiescence (breeding season) compared to mid-stage (non-breeding season). Based on RNA-seq transcriptional analysis, gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were used to analyze the testis in the quiescent and mid-stage. Our study found that circannual spermatogenesis is regulated by interactive networks including gonadotropin-releasing hormone (GnRH) secretion, regulation of actin cytoskeleton, and MAPK signaling pathways. Moreover, the number of genes associated with proliferation and differentiation (srf, nr4a1), cell cycle (ppard, ccnb2), and apoptosis (xiap) were up-regulated in the mid-stage. With the maximum energy saving, this seasonal pattern of T. s. elegans determines optimal reproductive success and thus adapts better to the environment. These results provide the basis for the invasion mechanism of T. s. elegans and lay the foundation for deeper insight into the molecular mechanism of seasonal spermatogenesis in reptiles.

Tributyltin chloride (TBTCL) induces cell injury via dysregulation of endoplasmic reticulum stress and autophagy in Leydig cells

Tributyltin chloride (TBTCL), a commonly used antiseptic substance, is commonly found in the environment. Human exposure to TBTCL through the consumption of contaminated seafood, fish, or drinking water has aroused concern. It is well-characterized that TBTCL has multiple detrimental effects on the male reproductive system. However, the potential cellular mechanisms are not fully elucidated. Here, we characterized molecular mechanisms of TBTCL-induced cell injury in Leydig cells, a critical supporter for spermatogenesis. We showed that TBTCL induces apoptosis and cell cycle arrest in TM3 mouse Leydig cells. RNA sequencing analyses revealed that endoplasmic reticulum (ER) stress and autophagy were potentially involved in TBTCL-induced cytotoxicity. We further showed that TBTCL causes ER stress and inhibited autophagy flux. Notably, the inhibition of ER stress attenuates not only TBTCL-induces autophagy flux inhibition but also apoptosis and cell cycle arrest. Meanwhile, the activation of autophagy alleviates, and inhibition of autophagy exaggerates TBTCL-induced apoptosis and cell cycle arrest flux. These results suggest that TBTCL-induced ER stress and autophagy flux inhibition contributed to apoptosis and cell cycle arrest in Leydig cells, providing novel understanding into the mechanisms of TBTCL-induced testis toxicity.

Cytoskeletal orchestration of glucose uptake in Sertoli cell to support efferocytosis of apoptotic germ cells

Efferocytosis of non-viable germ cells by Sertoli cells (SCs) constitutes a sentinel for testis homeostasis, yet how SCs signal for the metabolic and cytoskeletal adaption to this energetically costly process remains unexplored. Spectrin is membrane-associated periodic skeleton assembled into an actin-spectrin-based cytoskeletal structure with an interaction with glucose transporter Glut1. The contribution of spectrin to glucose uptake and efferocytosis is unknown. In this study, we identified a cross-regulation between glucose metabolism and efferocytosis in SCs. Pharmacological or genetic inhibition of glucose uptake or glycolysis compromises efferocytosis activity. We further found that βII-spectrin is a hitherto unappreciated regulator of glucose metabolism and cytoskeletal architecture. βII-spectrin deficiency impairs glucose uptake and lactate production in SCs. Moreover, a defective assembly of cytoskeleton and a loss of blood-testis barrier integrity are also featured by SCs deficient in βII-spectrin. The disruption in glucose metabolism and cytoskeletal organization synergistically lead to a defective efferocytosis. In vivo siRNA-mediated targeting of βII-spectrin in testis causes an obvious morphological aberration in seminiferous epithelium with the presence of exfoliated germ cells and multinucleated giant cells. Importantly, a decrease in expression of αII/βII-spectrin was observed in testes of Adjudin-induced infertility model. By exploring the functional relevance of βII-spectrin to the metabolic and cytoskeletal regulation of efferocytosis, our study proposes a potential link between βII-spectrin deregulation and male infertility.

Knockdown of disheveled-associated activator of morphogenesis 2 disrupts cytoskeletal organization and phagocytosis in rat Sertoli cells

Disheveled-associated activator of morphogenesis 2 (DAAM2) regulates actin polymerization and cell motility. In this study, we investigated the role of DAAM2 in the cytoskeleton and phagocytosis of rat Sertoli cells in vitro and in vivo through siRNA transfection and intratesticular injection. We found that knockdown of DAAM2 significantly attenuated cytoskeletal and tight junction marker expression and reduced the integrity of the Sertoli cell monolayer. In rats, loss of DAAM2 induced disarrangement and deformation of sperms and promoted accumulation of apoptotic sperms in the testis, accompanied by morphological abnormalities in the blood-testis barrier. DAAM2 silencing also reduced the ability of Sertoli cells to engulf apoptotic spermatogenic cells and green fluorescence-labeled beads. RNA sequencing and bioinformatics analysis revealed that phagocytosis and cytoskeleton-related genes and pathways were significantly associated with DAAM2. Our study suggests that DAAM2 may be involved in spermatogenesis possibly by regulating cytoskeleton organization and phagocytosis of Sertoli cells.

Identification and profiling of microRNAs during yak's testicular development

BACKGROUND

Normal testicular development is highly crucial for male reproduction and is a precondition for spermatogenesis that is the production of spermatozoa in the testes. MiRNAs have been implicated in several testicular biological processes, including cell proliferation, spermatogenesis, hormone secretion, metabolism and reproductive regulation. In the present study, we used deep sequencing data to study the functions of miRNAs during testicular development and spermatogenesis, by analyzing the expression patterns of small RNAs in 6-, 18- and 30-month-old yak testis tissues.

RESULTS

A total of 737 known and 359 novel miRNAs were obtained from 6-, 18- and 30-month-old yak testes. In all, we obtained 12, 142 and 139 differentially expressed (DE) miRNAs in 30- vs. 18-, 18- vs. 6-, and 30- vs. 6-month-old testes, respectively. Gene Ontology (GO) annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis of all DE miRNA target genes revealed BMP2, TGFB2, GDF6, SMAD6, TGFBR2 and other target genes as participants in different biological processes, including TGF-β, GnRH, Wnt, PI3K-Akt, MAPK signaling pathways and several other reproductive pathways. In addition, quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) was used to detect the expression of seven randomly selected miRNAs in 6-, 18- and 30-month-old testes, and the results were consistent with the sequencing data.

CONCLUSIONS

The differential expression of miRNAs in yak testes at different development stages was characterized and investigated using deep sequencing technology. We believe that the results will contribute to further understanding the functions of miRNAs in regulating the development of yak testes and improving the reproductive performance of male yaks.

Cannabidiol-induced transcriptomic changes and cellular senescence in human Sertoli cells

Cannabidiol (CBD), one of the major cannabinoids in the plant Cannabis sativa L., is the active ingredient in a drug approved for the treatment of seizures associated with certain childhood-onset epileptic disorders. CBD has been shown to induce male reproductive toxicity in multiple animal models. We previously reported that CBD inhibits cellular proliferation in the mouse Sertoli cell line TM4 and in primary human Sertoli cells. In this study, using a transcriptomic approach with mRNA-sequencing analysis, we identified molecular mechanisms underlying CBD-induced cytotoxicity in primary human Sertoli cells. Analysis of differentially expressed genes demonstrated that DNA replication, cell cycle, and DNA repair were the most significantly affected pathways. We confirmed the concentration-dependent changes in the expression of key genes in these pathways using real-time PCR. mRNA sequencing showed upregulation of a group of genes tightly associated with the senescence-associated secretory phenotype (SASP) and with the activation of the p53 signaling pathway, a key upstream event in cellular senescence. Prolonged treatment of 10 μM CBD-induced cellular senescence, as evidenced by the stable cessation of proliferation and the activation of senescence-associated β-galactosidase (SA-β-gal), 2 hallmarks of senescence. Additionally, using real-time PCR and Western blotting assays, we observed that CBD treatment increased the expression of p16, an important marker of cellular senescence. Taken together, our results show that CBD exposure disturbs various interrelated signaling pathways and induces cellular senescence in primary human Sertoli cells.

Epigenetic programming of TBX2/CX43 mediates lower sperm quality in male offspring induced by prenatal dexamethasone exposure

Decreased sperm quality is the main cause of male infertility. Studies have found that prenatal dexamethasone exposure (PDE) decreases sperm quality in male offspring after birth, but the mechanism is unclear. Wistar pregnant rats were subcutaneously injected with 0.1, 0.2 and 0.4 mg/kg.d dexamethasone at gestational day 9-20. The testes and sperm of first-generation (F1) offspring were collected, and F1 offspring were mated with wild-type female rats to obtain F2. Compared with the control group, F1 offspring in PDE group had lower sperm count and motility after birth, and the deformity rate increased. F2 fetal rats' body length and weight decreased, and the intrauterine growth retardation rate increased. Meanwhile, PDE decreased the expression of connexin 43 (CX43) in offspring testes, while T-box transcription factor 2 (TBX2) promoter region histone 3 lysine 9 acetylation (H3K9ac) level and its expression were increased. Traced back to F1 fetus testes, PDE increased the expression of glucocorticoid receptor (GR) and P300, activated GR protein into the nucleus, and made GR act on the TBX2 promoter region. Further, a series of Sertoli cell interventions confirmed that dexamethasone promoted GR to recruit P300, increased the H3K9ac level of TBX2 promoter region and its expression, and inhibited the expression of CX43. This study confirmed that PDE decreased sperm quality of male offspring, which is related to the epigenetic programming of TBX2/CX43 in the Sertoli cells, provided a theoretical and experimental basis for guiding the rational use of drugs during pregnancy.

hnRNPH1 establishes Sertoli-germ cell crosstalk through cooperation with PTBP1 and AR, and is essential for male fertility in mice

Spermatogenesis depends on the crosstalk of Sertoli cells (SCs) and germ cells. However, the gene regulatory network establishing the communications between SCs and germ cells remains unclear. Here, we report that heterogeneous nuclear ribonucleoprotein H1 (hnRNPH1) in SCs is essential for the establishment of crosstalk between SCs and germ cells. Conditional knockout of hnRNPH1 in mouse SCs leads to compromised blood-testis barrier function, delayed meiotic progression, increased germ cell apoptosis, sloughing of germ cells and, eventually, infertility of mice. Mechanistically, we discovered that hnRNPH1 could interact with the splicing regulator PTBP1 in SCs to regulate the pre-mRNA alternative splicing of the target genes functionally related to cell adhesion. Interestingly, we also found hnRNPH1 could cooperate with the androgen receptor, one of the SC-specific transcription factors, to modulate the transcription level of a group of genes associated with the cell-cell junction and EGFR pathway by directly binding to the gene promoters. Collectively, our findings reveal a crucial role for hnRNPH1 in SCs during spermatogenesis and uncover a potential molecular regulatory network involving hnRNPH1 in establishing Sertoli-germ cell crosstalk.

Developmental toxicity window of fetal testicular injury in offspring mice induced by prenatal amoxicillin exposure at different time, doses and courses

Amoxicillin is widely used in the clinical treatment of syphilis, gonorrhea and other infectious diseases during pregnancy, but the effects of prenatal amoxicillin exposure (PAmE) on fetal testicular development have not been reported. Based on the characteristics of clinical medication, Kunming mice were orally gavaged with amoxicillin during pregnancy at different time (mid- or late-pregnancy), doses (75, 150 or 300 mg/kg·d) or courses (single- or multi-course). The results showed that compared with the control group, PAmE resulted in fetal testicular abnormal morphological development, cell proliferation inhibition and apoptosis enhancement, Leydig cell steroid synthase system (SF1, StAR, P450scc, CYP17a1) expression inhibition, and fetal blood testosterone levels decreased. Among them, the late-pregnancy and high-dose amoxicillin groups had severe damage, while the damage in different course groups was basically the same. Meanwhile, PAmE could damage the number and function of germ cells at all time, doses and courses, but had no obvious effect on Sertoli cells. It was further found that PAmE inhibited fetal testis AKT and ERK signaling pathways in late pregnancy and high dose, while the damage in different course groups was basically the same. In summary, this study proposed the developmental toxicity window of fetal testicular injury induced by PAmE in late-pregnancy and high-dose and its related mechanism of AKT and ERK signaling pathway, which provided a theoretical and experimental basis for guiding rational drug use during pregnancy and effectively evaluating the risk of fetal testicular developmental toxicity.

Sertoli cells-derived exosomal miR-30a-5p regulates ubiquitin E3 ligase Zeb2 to affect the spermatogonial stem cells proliferation and differentiation

The role of spermatogonial stem cells (SSCs) is crucial in spermatogenesis, and extracellular vesicles (EVs) have been the focus of research as an important intercellular communication mechanism. Various endogenous regulatory factors secreted by Sertoli cells (SCs) can affect the self-maintenance and regeneration of SSCs, but little is known about the roles of SCs-derived exosomal microRNAs (miRNAs) on SSCs. In this study, we aimed to explore the regulation of the SCs-derived exosomal miR-30a-5p on SSCs proliferation and differentiation. EVs from the SCs were detected by electron microscopy and nanoparticle tracking analysis (NTA). Subsequently, the SSCs were treated with the SCs-derived extracellular vesicles (SCs-EVs). CCK-8 assay and EdU staining was applied to detect the cell proliferation, and the results indicated that SCs-EVs promoted the SSCs proliferation. Western blot detection of the SSCs markers (Gfrα1, Plzf, Stra8, and C-kit) indicated that SCs-EVs promoted the SSCs differentiation. Additionally, we found that SCs-EVs secreted miR-30a-5p to show the promoting effects. Besides, we discovered that miR-30a-5p targeted zinc finger E-box binding homeobox 2 (Zeb2) to regulate the ubiquitination of fibroblast growth factor 9 (Fgf9) in SSCs. miR-30a-3p/Zeb2/Fgf9 promoted the SSCs proliferation and differentiation by activating the mitogen‑activated protein kinase (MAPK) signaling pathway. Taken together, our study showed that SCs-EVs can transport miR-30a-5p to SSCs and affect SSCs proliferation and differentiation by regulating the MAPK signaling pathway via Zeb2/Fgf9. This paper disclosed a novel molecular mechanism that regulates SSCs proliferation and differentiation, which could be valuable for the treatment of male infertility.

Carob extract induces spermatogenesis in an infertile mouse model via upregulation of Prm1, Plzf, Bcl-6b, Dazl, Ngn3, Stra8, and Smc1b

ETHNOPHARMACOLOGICAL RELEVANCE

Ethnopharmacological studies for drug discovery from natural compounds play an important role for developing current therapeutical platforms. Plants are a group of natural sources which have been served as the basis in the treatment of many diseases for centuries. In this regard, Ceratonia siliqua (carob) is one of the herbal medicine which is traditionally used for male infertility treatments. But so far the main mechanisms for effects of carob are unknown. Here, we intend to investigate the ability of carob extract to induce spermatogenesis in an azoospermia mouse model and determine the mechanisms that underlie its function.

AIM OF THE STUDY

This is a pre-clinical animal model study to evaluate the effect of carob extract in spermatogenesis recovery.

METHODS

We established an infertile mouse model with the intent to examine the ability of carob extract as a potential herbal medicine for restoration of male fertility. Sperm parameters, as well as gene expression dynamics and levels of spermatogenesis hormones, were evaluated 35 days after carob administration.

RESULTS

Significant enhanced sperm parameters (P < 0.05) showed that the carob extract could induce spermatogenesis in the infertile mouse model. Our data suggested an anti-apototic and inducer role in the expressions of cell cycle regulating genes. Carob extract improved the spermatogenesis niche by considerable affecting Sertoli and Leydig cells (P < 0.05). The carob-treated mice were fertile and contributed to healthy offspring that matured. Our data confirmed that this extract triggered the hormonal system, the spermatogenesis-related gene expression network, and signaling pathways to induce and promote sperm production with notable level (P < 0.05). We found that the aqueous extract consisted of a polar and mainly well water-soluble substance. Carob extract might upregulate spermatogenesis hormones via its amino acid components, which were detected in the extract by liquid chromatography-mass spectrometry (LC-MS).

CONCLUSION

Our results strongly suggest that carob extract might be a promising future treatment option for male infertility. This finding could pave the way for clinical trials in infertile men. This is the first study that has provided reliable, strong pre-clinical evidence for carob extract as an effective candidate for fertility recovery in cancer-related azoospermia.

Global 3'-UTRome of porcine immature Sertoli cells altered by acute heat stress

Alternative polyadenylation (APA) affects the composition of cis-elements in 3'-untranslated region (3'-UTR), to regulate gene expression and localization, and subsequently the downstream biological processes. Acute heat stress could change rapidly the cellular transcriptome, however the underlying molecular changes are less explored. Here, we systematically catalogued the global 3'-UTRome dynamics, by analyzing our previously reported transcriptome sequencing data of porcine immature Sertoli (iST) cells before (Control group), acute heat stress treatment at 43 °C for 0.5h (HS0.5 group), and 36h recovery culture (HS0.5-R36h group) after acute heat stress treatment. After three group comparisons (HS0.5 vs. Control, HS0.5-R36 vs. HS0.5, and HS0.5-R36 vs. Control), DaPars (dynamic analysis of alternative polyadenylation) identified 639, 464 and 290 mRNAs, and APAtrap (a tool to identify APA sites and detect changes of APA site usage) identified 713, 518 and 321 mRNAs, with significantly different 3'-UTRs (Padj.≤0.05), respectively. These genes with different 3'-UTR patterns were mainly enriched in P53, glycolysis/gluconeogenesis, HIF-1, apoptosis, PI3K-Akt and AMPK signaling pathways. Further analysis identified that average 3'-UTR lengths of Acss2, Inpp1 and Nr1h4 were more than 140 nt longer (HS0.5-R36 vs. HS0.5), and contained different cis-elements (PAS, CPE and microRNA binding sites). Moreover, Hsp70.2, Inhbb and Dhrs were identified to have extremely different 3'-UTR abundances. Further 3'RACE assays validated several 3'-UTRs of Nr1h4, and RT-qPCR confirmed the abundance changes of different 3'-UTR isoforms for Nr1h4 and Hsp70.2. Our findings provide useful information and resources to further uncover the molecular role of 3'-UTR, in regulating the response of porcine iST cells to acute heat stress.

RIG-I and MDA5 are modulated by bone morphogenetic protein (BMP6) and are essential for restricting Zika virus infection in human Sertoli cells

Sexual transmission of Zika virus (ZIKV) is associated with virus persistence in the testes and shedding in the seminal fluid for months after recovery. We previously demonstrated that ZIKV can establish long-term replication without causing cytotoxicity in human Sertoli cells (SC), responsible for maintaining the immune privileged compartment of seminiferous tubules. Functional gene expression analyses also predicted activation of multiple virus sensing pathways including TLR3, RIG-I, and MDA5. Here, we elucidated which of the RNA virus sensing receptors play a decisive role in restricting ZIKV replication. We show that both poly I:C and IFN-β treatment induced a robust antiviral state and reduced ZIKV replication significantly, suggesting that virus sensing and antiviral signaling are functional in SC. Silencing of TLR3, 7, and 9 did not affect virus replication kinetics; however, both RIG-I and MDA5 played a synergistic role in inducing an anti-ZIKV response. Further, the impact of SC-specific immunosuppressive pathways that collectively regulate SC function, specifically the TGF-β superfamily members, TGF-β, Activin A, and BMP6, on ZIKV replication was investigated. While ZIKV did not modulate the expression of TGF-β and Activin A, BMP6 signaling was suppressed at later stages of infection. Notably, treatment with BMP6 increased IFN-β, p-IRF3, and p-STAT1 levels, and expression of key interferon-stimulated genes including MDA5, suggesting that BMP6 enhances antiviral response in SC. Collectively, this study further delineates the key role of the RIG-I-like receptors in sensing ZIKV in SC, and reveals a novel role of BMP6 in modulating innate immune and antiviral response in the testes.

Impact of endocrine disrupting chemicals and pharmaceuticals on Sertoli cell development and functions

Sertoli cells play essential roles in male reproduction, from supporting fetal testis development to nurturing male germ cells from fetal life to adulthood. Dysregulating Sertoli cell functions can have lifelong adverse effects by jeopardizing early processes such as testis organogenesis, and long-lasting processes such as spermatogenesis. Exposure to endocrine disrupting chemicals (EDCs) is recognized as contributing to the rising incidence of male reproductive disorders and decreasing sperm counts and quality in humans. Some drugs also act as endocrine disruptors by exerting off-target effects on endocrine tissues. However, the mechanisms of toxicity of these compounds on male reproduction at doses compatible with human exposure are still not fully resolved, especially in the case of mixtures, which remain understudied. This review presents first an overview of the mechanisms regulating Sertoli cell development, maintenance, and functions, and then surveys what is known on the impact of EDCs and drugs on immature Sertoli cells, including individual compounds and mixtures, and pinpointing at knowledge gaps. Performing more studies on the impact of mixtures of EDCs and drugs at all ages is crucial to fully understand the adverse outcomes these chemicals may induce on the reproductive system.

Rhamnazin ameliorates 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin-evoked testicular toxicity by restoring biochemical, spermatogenic and histological profile in male albino rats

2,3,7,8 tetrachlorodibenzo-p-dioxin (TCDD) is a potential environmental toxin that has the ability to affect male reproductive tract. Rhamnazin is a naturally present flavone that displays multiple medicinal properties. Therefore, the current study was designed to determine the mitigative role of rhamnazin against TCDD induced reproductive damage. 48 adult male albino rats were randomly separated into four groups: control, TCDD (10 µgkg-1), TCDD + rhamnazin (10 µgkg-1 + 5 mgkg-1 respectively) and rhamnazin (5 mgkg-1). The trial was conducted for 56 days. TCDD intoxication notably affected superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GSR) and catalase (CAT) activities, besides reactive oxygen species (ROS) and malondialdehyde (MDA) concentrations were augmented. TCDD administration also lowered sperm motility, viability, sperm number, while it augmented the sperm morphological (tail, neck/midpiece and head) anomalies. Moreover, it decreased the levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH) and plasma testosterone. Moreover, TCDD reduced steroidogenic enzymes i.e., 17-beta hydroxysteroid dehydrogenase (17β-HSD), steroidogenic acute regulatory protein (StAR) and 3-beta hydroxysteroid dehydrogenase (3β-HSD) as well as B-cell lymphoma 2 (Bcl-2) expressions, but increased the expressions of Bcl-2-associated X protein (Bax) and cysteine-aspartic acid protease (Caspase-3). Furthermore, TCDD exposure also induced histopathological anomalies in testicular tissues. However, the supplementation of rhamnazin recovered all the mentioned damages in the testicles. The outcomes revealed that rhamnazin can ameliorate TCDD induced reproductive toxicity due to its anti-oxidant, anti-apoptotic and androgenic nature.