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Sichuan Da Xue Xue Bao. Yi Xue Ban =... May 2024Infertility affects an estimated 10 to 15 percent of couples worldwide, with approximately half of the cases attributed to male-related issues. Most men diagnosed with...
Infertility affects an estimated 10 to 15 percent of couples worldwide, with approximately half of the cases attributed to male-related issues. Most men diagnosed with infertility exhibit symptoms such as oligospermia, asthenospermia, azoospermia, and compromised sperm quality. Spermatogenesis is a complex and tightly coordinated process of germ cell differentiation, precisely regulated at transcriptional, posttranscriptional, and translational levels to ensure stage-specific gene expression during the development of spermatogenic cells and normal spermiogenesis. N-methyladenosine (mA) stands out as the most prevalent modification on eukaryotic mRNA, playing pivotal roles in various biological processes, including mRNA splicing, transportation, and translation. RNA methylation modification is a dynamic and reversible process primarily mediated by "writers", removed by "erasers", and recognized by "readers". In mammals, the aberrant methylation modification of mA on mRNA is associated with a variety of diseases, including male infertility. However, the precise involvement of disrupted mA modification in the pathogenesis of human male infertility remains unresolved. Intriguingly, a significant correlation has been found between the expression levels of mA regulators in the testis and the severity of sperm concentration, motility, and morphology. Aberrant expression patterns of mA regulatory proteins have been detected in anomalous human semen samples, including those of oligospermia, asthenozoospermia, and azoospermia. Furthermore, the examination of both sperm samples and testicular tissues revealed abnormal mRNA mA modification, leading to reduced sperm motility and concentration in infertile men. Consequently, it is hypothesized that dysregulation of mA modification might serve as an integral link in the mechanism of male infertility. This paper presents a comprehensive review of the recent discoveries regarding the spatial and temporal expression dynamics of mA regulators in testicular tissues and the correlation between deregulated mA regulators and human male infertility. Previous studies predominantly utilized constitutive or conditional knockout animal models for testicular phenotypic investigations. However, gene suppression in additional tissues could potentially influence the testis in constitutive knockout models. Furthermore, considering the compromised spermatogenesis observed in constitutive animals, distinguishing between the indirect effects of gene depletion on testicular development and its direct impact on the spermatogenic process is challenging, due to their intricate relationship. Such confounding factors might compromise the validity of the findings. To address this challenge, an inducible and conditional gene knockout model may serve as a superior approach. To date, nearly all reported studies have concentrated solely on the level changes of mA and its regulators in germs cells, while the understanding of the function of mA modification in testicular somatic cells remains limited. Testicular somatic cells, including peritubular myoid cells, Sertoli cells, and Leydig cells, play indispensable roles during spermatogenesis. Hence, comprehensive exploration of mA modification within these cells as an additional crucial regulatory mechanism is warranted. In addition, exploration into the presence of unique methylation mechanisms or mA regulatory factors within the testes is warranted. To elucidate the role of mA modification in germ cells and testicular somatic cells, detailed experimental strategies need to be implemented. Among them, manipulation of the levels of key enzymes involved in mA methylation and demethylation might be the most effective approach. Moreover, comprehensive analysis of the gene expression profiles involved in various signaling pathways, such as Wnt/β-catenin, Ras/MAPK, and Hippo, in mA-modified germ cells and testicular somatic cells can provide more insight into its regulatory role in the spermatogenesis process. Further research in this area could provide valuable insights for developing innovative strategies to treat male infertility. Finally, considering the mitigation impact of mA imbalance regulation on disease, investigation concerning whether restoring the equilibrium of mA modification regulation can restore normal spermatogenesis function is essential, potentially elucidating the pivotal clinical significance of mA modulation in male infertility.
PubMed: 38948273
DOI: 10.12182/20240560103 -
Experimental & Molecular Medicine Jul 2024The reciprocal crosstalk between testicular Sertoli and Leydig cells plays a vital role in supporting germ cell development and maintaining testicular characteristics...
The reciprocal crosstalk between testicular Sertoli and Leydig cells plays a vital role in supporting germ cell development and maintaining testicular characteristics and spermatogenesis. Conventional 2D and the recent 3D assay systems fail to accurately replicate the dynamic interactions between these essential endocrine cells. Furthermore, most in vitro testicular tissue models lack the ability to capture the complex multicellular nature of the testis. To address these limitations, we developed a 3D multicellular testis-on-a-chip platform that effectively demonstrates the reciprocal crosstalk between Sertoli cells and the adjacent Leydig cells while incorporating various human testicular tissue constituent cells and various natural polymers infused with blood coagulation factors. Additionally, we identified SERPINB2 as a biomarker of male reproductive toxicity that is activated in both Sertoli and Leydig cells upon exposure to various toxicants. Leveraging this finding, we designed a fluorescent reporter-conjugated toxic biomarker detection system that enables both an intuitive and quantitative assessment of material toxicity by measuring the converted fluorescence intensity. By integrating this fluorescent reporter system into the Sertoli and Leydig cells within our 3D multicellular chip platform, we successfully developed a testis-on-chip model that can be utilized to evaluate the male reproductive toxicity of potential drug candidates. This innovative approach holds promise for advancing toxicity screening and reproductive research.
PubMed: 38945952
DOI: 10.1038/s12276-024-01258-3 -
Abdominal Radiology (New York) Jun 2024To assess the role of 3.0 T Diffusion Tensor Imaging (DTI) and Fiber Tractography (FT) of the testes in the work-up of nonobstructive azoospermia (NOA).
PURPOSE
To assess the role of 3.0 T Diffusion Tensor Imaging (DTI) and Fiber Tractography (FT) of the testes in the work-up of nonobstructive azoospermia (NOA).
METHODS
This prospective study included consecutive NOA men and controls. A 3.0 T scrotal MRI was performed, including DTI. The testicular apparent diffusion coefficient (ADC) and fractional anisotropy (FA) were calculated. FT reconstructions were created. The Kruskal-Wallis test, followed by pairwise comparisons, assessed differences in testicular ADC and FA between NOA histologic phenotypes (group 1: hypospermatogenesis; group 2: maturation arrest; and group 3: Sertoli cell-only syndrome) and normal testes. The Mann-Whitney-U test compared ADC and FA between NOA testes with positive and negative sperm retrieval. Visual assessment of the testicular fiber tracts was performed. Fiber tracts fewer in number, of reduced thickness, disrupted and/or disorganized were considered "abnormal". Chi-square tests and binary logistic regression analysis assessed variations in testicular fiber tracts morphology.
RESULTS
Twenty-nine NOA men (mean age: 39 ± 5.93 years) and 20 controls (mean age: 26 ± 5.83 years) were included for analysis. Higher ADC (p < 0.001) and FA (p < 0.001) was observed in NOA testes compared to controls. Differences in FA were found between groups 1 and 3 (0.07 vs 0.10, p = 0.26) and groups 2 and 3 (0.07 vs 0.10, p = 0.03), but not between groups 1 and 2 (p = 0.66). An increase in FA was observed in NOA testes with Sertoli cell-only syndrome compared to hypospermatogenesis and maturation arrest. FA was higher in NOA testes with negative results for the presence of sperm compared to those with positive results (0.09 vs 0.07, p = 0.006). FT showed "abnormal" fiber tracts in NOA testes (p < 0.001).
CONCLUSION
3.0 T DTI and FT provide an insight into deranged spermatogenesis in NOA testes.
PubMed: 38940912
DOI: 10.1007/s00261-024-04457-8 -
Animals : An Open Access Journal From... Jun 2024The purpose of this study was to analyze the ultrastructure of the testes of sexually immature calves and reproductive bulls of the Polish Holstein-Friesian...
The purpose of this study was to analyze the ultrastructure of the testes of sexually immature calves and reproductive bulls of the Polish Holstein-Friesian Black-and-White breed. Utilizing TEM, this study identified three distinct stages of seminiferous tubule development in calves, characterized by varying shapes, distributions, and arrangements of individual cells. In immature animals, early developing spermatocytes, prespermatogonia, and pre-Sertoli cells were observed within the seminiferous tubules. In sexually mature bulls, all cells of the spermatogenic series were observed, situated on a thin, multilayered basal lamina, which forms characteristic undulations. An abundant smooth endoplasmic reticulum was observed in the cytoplasm of spermatogonia in both groups of animals, forming characteristic membranous swirls. In adult bulls, spermatogonia maintain contact with each other through numerous cytoplasmic bridges and cell connections, forming small spaces with visible microvilli between them. The ultrastructural analysis facilitated the identification of morphological changes occurring during the maturation of pre-Sertoli cells, transitioning from a large euchromatic nucleus to a nucleus in which the formation of characteristic vesicles and tubules could be observed. It should also be emphasized that two types of Sertoli cells, namely dark and light electron-dense cells, can be found in cattle. These cells differ from each other, indicating that they may perform different functions. The widespread recognition of the presence of two types of Sertoli cells in cattle will undoubtedly contribute to a better understanding of the processes occurring within the testes and provide a basis for further research in this area.
PubMed: 38929396
DOI: 10.3390/ani14121777 -
Genes May 2024Azoospermia is a form of male infertility characterized by a complete lack of spermatozoa in the ejaculate. Sertoli cell-only syndrome (SCOS) is the most severe form of...
Azoospermia is a form of male infertility characterized by a complete lack of spermatozoa in the ejaculate. Sertoli cell-only syndrome (SCOS) is the most severe form of azoospermia, where no germ cells are found in the tubules. Recently, FANCM gene variants were reported as novel genetic causes of spermatogenic failure. At the same time, FANCM variants are known to be associated with cancer predisposition. We performed whole-exome sequencing on a male patient diagnosed with SCOS and a healthy father. Two compound heterozygous missense mutations in the FANCM gene were found in the patient, both being inherited from his parents. After the infertility assessment, the patient was diagnosed with diffuse astrocytoma. Immunohistochemical analyses in the testicular and tumor tissues of the patient and adequate controls showed, for the first time, not only the existence of a cytoplasmic and not nuclear pattern of FANCM in astrocytoma but also in non-mitotic neurons. In the testicular tissue of the SCOS patient, cytoplasmic anti-FANCM staining intensity appeared lower than in the control. Our case report raises a novel possibility that the infertile carriers of FANCM gene missense variants could also be prone to cancer development.
Topics: Humans; Male; Astrocytoma; Sertoli Cell-Only Syndrome; Mutation, Missense; Adult; Exome Sequencing; DNA Helicases; Azoospermia
PubMed: 38927643
DOI: 10.3390/genes15060707 -
Reproductive Biology and Endocrinology... Jun 2024Testis is an immune privileged organ, which prevents the immune response against sperm antigens and inflammation. Testicular cells responsible for immune tolerance are...
BACKGROUND
Testis is an immune privileged organ, which prevents the immune response against sperm antigens and inflammation. Testicular cells responsible for immune tolerance are mainly Sertoli cells, which form the blood-testis barrier and produce immunosuppressive factors. Sertoli cells prevent inflammation in the testis and maintain immune tolerance by inhibiting proliferation and inducing lymphocyte apoptosis. It has been shown that 9-cis-retinoic acid (9cRA) blocks ex vivo apoptosis of peripheral blood lymphocytes and promotes the differentiation of Treg cells in the gut. However, the role of retinoid signaling in regulating the immune privilege of the testes remains unknown.
OBJECTIVE
The aim of this study was to determine whether 9cRA, acting via the retinoic acid receptors (RAR) and the retinoic X receptors (RXR), controls the immunomodulatory functions of Sertoli cells by influencing the secretion of anti-inflammatory/pro-inflammatory factors, lymphocyte physiology and Treg cell differentiation.
METHODS
Experiments were performed using in vitro model of co-cultures of murine Sertoli cells and T lymphocytes. Agonists and antagonists of retinoic acid receptors were used to inhibit/stimulate retinoid signaling in Sertoli cells.
RESULTS
Our results have demonstrated that 9cRA inhibits the expression of immunosuppressive genes and enhances the expression of pro-inflammatory factors in Sertoli cells and lymphocytes, increases lymphocyte viability and decreases apoptosis rate. Moreover, we have found that 9cRA blocks lymphocyte apoptosis acting through both RAR and RXR and inhibiting FasL/Fas/Caspase 8 and Bax/Bcl-2/Caspase 9 pathways. Finally, we have shown that 9cRA signaling in Sertoli cells inhibits Treg differentiation.
CONCLUSION
Collectively, our results indicate that retinoid signaling negatively regulates immunologically privileged functions of Sertoli cells, crucial for ensuring male fertility. 9cRA inhibits lymphocyte apoptosis, which can be related to the development of autoimmunity, inflammation, and, in consequence, infertility.
Topics: Male; Animals; Sertoli Cells; T-Lymphocytes, Regulatory; Signal Transduction; Mice; Tretinoin; Cell Differentiation; Alitretinoin; Receptors, Retinoic Acid; Apoptosis; Coculture Techniques; Mice, Inbred C57BL; Cells, Cultured; Immunomodulation
PubMed: 38926848
DOI: 10.1186/s12958-024-01246-2 -
Ecotoxicology and Environmental Safety Jun 2024This study investigated the effects of compound probiotics (CP) on AFB-induced cytotoxicity in Sertoli TM4 cells. The L9 (3 × 3) orthogonal test was conducted to...
This study investigated the effects of compound probiotics (CP) on AFB-induced cytotoxicity in Sertoli TM4 cells. The L9 (3 × 3) orthogonal test was conducted to determine the optimal CP required for high AFB degradation in the artificial gastrointestinal fluid in vitro. The maximal AFB degradation rate was 40.55 % (P < 0.05) when the final viable count was 1.0 × 10 CFU/mL for Bacillus subtilis, Lactobacillus casein, and Saccharomyces cerevisiae. The effects of CP and the CP supernatant (CPS) on TM4 cell viability were evaluated to achieve the optimal protective conditions. When CPS4 (corresponding to CP viable counts of 1.0 × 10 CFU/mL) was added to the TM4 cells for 24 h, the cell viability reached 108.86 % (P < 0.05). AFB reduced TM4 cell viability in a concentration- and time-dependent manner at an AFB concentration ranging from 0 to 1.5 μM after 48-h AFB exposure. The optimal AFB concentration/times for low- and high damage models were 0.5 and 1.25 μM both for 24 h, which decreased viability to 76.04 % and 65.35 %, respectively. however, CPS4 added to low- and high-damage models increased the cell viability to 97.43 % and 75.12 %, respectively (P < 0.05). Transcriptome sequencing was performed based on the following designed groups: the control, 0.5 μM AFB, 1.25 μM AFB, CPS4, and CPS4+0.5 μM AFB. The Kyoto encyclopedia of genes and genomes (KEGG) pathway enrichment analysis was further performed to identify significantly enriched signaling pathways, which were subsequently verified. It was shown that AFB induced apoptosis by blocking the PI3K-AKT-mTOR pathway and upregulating autophagy proteins such as LC3B, Beclin1, and ATG5 while inhibiting autophagic flux. CPS4 promoted AFB degradation, activated the p62-NRF2 antioxidant, and inhibited ROS/TRPML1 pathways, thereby reducing ROS production and inflammation and ultimately alleviating AFB-induced autophagy and apoptosis. These findings supports the potential of probiotics to protect the male reproductive system from toxin damage.
PubMed: 38925031
DOI: 10.1016/j.ecoenv.2024.116619 -
Annals of the New York Academy of... Jun 2024Infants born with severe central disorders of the hypothalamic-pituitary-gonadal axis leading to gonadotropin deficiency not only lack pubertal development in... (Review)
Review
Infants born with severe central disorders of the hypothalamic-pituitary-gonadal axis leading to gonadotropin deficiency not only lack pubertal development in adolescence, but also lack infantile mini-puberty. This period of mini-puberty, where infants have gonadotropin and sex steroid concentrations up into the adult range, is vital for future reproductive capacity, particularly in boys. At present, there is no consensus on the diagnosis or management of infants with gonadotropin deficiency due to congenital hypogonadotropic hypogonadism or multiple pituitary hormone deficiency. Case series suggest that gonadotropin treatment in male infants with absent mini-puberty is effective in promoting both testicular descent in those with undescended testes and also facilitating increased penile size. Moreover, replacement with follicle-stimulating hormone increases the testicular Sertoli cell population, measurable as an increase in testicular volume and inhibin B, thus hypothetically increasing the capacity for spermatogenesis in adult life for these patients. However, long-term follow-up data is limited for both outcomes pertaining to fertility and nonreproductive sequelae, including neurodevelopment and psychological well-being. The use of international registries for patients with gonadotropin deficiency is a key element in the collection of high-quality, geographically widespread data to inform best-practice management from birth to adulthood.
PubMed: 38924109
DOI: 10.1111/nyas.15177 -
Ecotoxicology and Environmental Safety Jun 2024This study explored the regulatory role of bta-miR-149-3p in the inflammatory response induced by microcystin-leucine arginine (MC-LR) exposure in bovine Sertoli cells....
This study explored the regulatory role of bta-miR-149-3p in the inflammatory response induced by microcystin-leucine arginine (MC-LR) exposure in bovine Sertoli cells. The research endeavored to enhance the comprehension of the epigenetic mechanisms underlying MC-LR-induced cytotoxicity in Sertoli cells and establish a foundation for mitigating these effects in vitro. In this study, we elucidated the regulatory mechanism of bta-miR-149-3p in the MC-LR-induced inflammatory response by verifying the target gene of bta-miR-149-3p through luciferase assays and treating the cells with a bta-miR-149-3p inhibitor for 24 h. The results demonstrate that nuclear factor κB (NF-κB) acts as a downstream target gene of bta-miR-149-3p, which inhibits the MC-LR-induced inflammatory response in bovine Sertoli cells. This inhibition occurs by regulating the downregulation of tight junction constitutive proteins of the blood-testis barrier (BTB) through the suppression of the TLR-4/NF-κB signaling pathway (p < 0.05) and the up-regulation of the adhesion junction protein β-catenin (p < 0.05). Notably, MC-LR exposure resulted in the up-regulation (p < 0.05) of inflammatory cytokines (IL-6, IL-1β, and NLRP3) and the down-regulation (p < 0.05) of BTB tight junction constitutive proteins (ZO-1, Occludin) in Sertoli cells. Furthermore, the BTB constitutive protein ZO-1 exhibited significant down-regulation in Sertoli cells pretreated with the bta-miR-149-3p inhibitor compared to controls (p < 0.05), while Occludin showed no significant difference from CTNNB1 (p > 0.05). In summary, our findings suggest that bta-miR-149-3p suppresses the MC-LR-induced inflammatory response and alterations in the expression of BTB proteins in bovine Sertoli cells by inhibiting the TLR-4/NF-κB signaling pathway.
PubMed: 38917588
DOI: 10.1016/j.ecoenv.2024.116636 -
BioRxiv : the Preprint Server For... Jun 2024Spermatogenesis is a biological process within the testis that produces haploid spermatozoa for the continuity of species. Sertoli cells are somatic cells in the...
Spermatogenesis is a biological process within the testis that produces haploid spermatozoa for the continuity of species. Sertoli cells are somatic cells in the seminiferous epithelium that orchestrate spermatogenesis. Cyclic reorganization of Sertoli cell actin cytoskeleton is vital for spermatogenesis, but the underlying mechanism remains largely unclear. Here, we report that RNA-binding protein PTBP1 controls Sertoli cell actin cytoskeleton reorganization by programming alternative splicing of actin cytoskeleton regulators. This splicing control enables ectoplasmic specializations, the actin-based adhesion junctions, to maintain the blood-testis barrier and support spermatid transport and transformation. Particularly, we show that PTBP1 promotes actin bundle formation by repressing the inclusion of exon 14 of , a kinase present at the ectoplasmic specialization. Our results thus reveal a novel mechanism wherein Sertoli cell actin cytoskeleton dynamics is controlled post-transcriptionally by utilizing functionally distinct isoforms of actin regulatory proteins, and PTBP1 is a critical regulatory factor in generating such isoforms.
PubMed: 38915624
DOI: 10.1101/2024.06.12.598725