The blood-testis barrier and its implications for male contraception

Comparative proteomic and transcriptomic analysis of testicular tissue of yaks with or without cryptorchidism

Yak is a large plateau mammal with low reproduction rate, while cryptorchidism is a major reproductive disorder associated with infertility in highland yaks. To better understand the occurrence of cryptorchidism and its regulatory mechanisms in yaks, we conducted a multi-omic analysis, and screened a total of 4456 differentially expressed genes (DEGs) and 332 differentially expressed proteins (DEPs) between normal and unilateral cryptorchid testes of yaks using high-throughput transcriptome sequencing (RNA-seq) and Tandem Mass Tag (TMT)-based proteomics techniques, with testes from yaks with cryptorchidism as the target. Enrichment analysis revealed that the DEGs were associated with cell growth, sperm motility, immune regulation, and intercellular tight junctions, and were mainly enriched in pathways related to cell differentiation; amino acid, sugar, and lipid metabolism; cell adhesion, and hypoxia tolerance. The results of protein interactions network analyses indicated tight interactions between the differential proteins CCT2, CCT4, CCT5, FZR1, and PSMA8. In conclusion. This expression of these differential genes and proteins dysregulation may lead to the obstruction of the testicular descent process or the abnormal development of the testis, potentially leading to cryptorchidism. The results of this study laid a foundation for the screening of key candidate genes and proteins for cryptorchidism in yak, and also provided a theoretical basis for the research molecular mechanism of reproductive system diseases in yak and plateau animals.

Unseen toxins: Exploring the human health consequences of micro and nanoplastics

Micro and nanoplastics (MNPs) contamination constitute a pressing global issue with considerable ramifications for human health. Particles originating from the decomposition of plastic waste permeate ecosystems and disturb biological systems, especially the gastrointestinal (GI) tract. MNPs compromise the intestinal barrier, provoke oxidative stress, inflammation, and immunological dysfunction, and modify gut microbiota, which is associated with metabolic problems, inflammatory bowel disease (IBD), and colorectal cancer. MNPs traverse biological barriers beyond the gastrointestinal system, including the blood-brain barrier, colonic mucus layer, and placental barrier, resulting in accumulation in essential organs such as the liver, kidneys, and brain. This results in inflammatory damage, metabolic abnormalities, and oxidative stress, specifically affecting liver disease due to microbiota metabolite alteration and nephrotoxicity in the kidneys. Airborne MNPs pose an additional risk to respiratory health, aggravating ailments such as asthma, chronic obstructive pulmonary disease (COPD), and pulmonary fibrosis. At-risk groups, such as pregnant women, newborns, and the elderly, encounter increased dangers, as MNPs traverse the placental barrier and may induce neurological and intergenerational health consequences. These particles function as vectors for environmental pollutants, exacerbating their cardiovascular and neurological effects. Addressing the long-term consequences of MNP exposure necessitates interdisciplinary collaboration to enhance comprehension and alleviate their growing risk to human health.

The ferroptosis of sertoli cells inducing blood-testis barrier damage is produced by oxidative stress in cryptorchidism

Oxidative Stress (OS) is the main cause of damage to the Blood-Testis Barrier (BTB) in cryptorchidism, which seriously endangers male reproductive health. It is well known that the OS induced ferroptosis is an important cause of dysfunction in the body. However, it is still unknown whether BTB damage in cryptorchidism leads to ferroptosis of Sertoli cells. We establishing the cryptorchidism model through surgery to avoid the complex effects of drugs on the model animals, combined with in vitro culture of the primary Sertoli cells for validation, and the methods of immunofluorescence staining, Western blotting and Prussian blue staining were used to study the oxidative stress in cryptorchidism. The effects of ferroptosis of Sertoli cells inducing BTB damage caused by OS in cryptorchidism were analyzed. We found that the inhibition of Nrf-2/keap-1/HO-1 pathway resulted in decreased expression levels of Glutathione Peroxidase 4 (GPX4), Ferroportin 1 (FPN1), and increased expression of Ferritin light chain (FTL) protein. Our research further confirms that inhibiting ferroptosis reduced BTB damage by reflecting a decrease expression of Zonula Occludens protein 1 (ZO-1), Occludin and Claudin-11 protein caused by OS. In addition, we found that the testosterone (T) secretion disorders and the supplementation of T can alleviate the damage of the BTB in cryptorchidism, and this effect is achieved through the Androgen Receptor (AR). In conclusion, our study found that the inhibition of Nrf-2/keap-1/HO-1 pathway in testis and the reduction of Tight junction proteins (TJs) ZO-1, Occludin and Claudin-11 protein expression levels in cryptorchidic mice, indicated that the cryptorchidism triggering a serious reproductive disorder, and one of the important reasons is the OS induced ferroptosis of Sertoli cells, which ultimately leads to the damage of the BTB. This findings may have important implications in the field of male reproductive disorders.

Hepatitis B Virus Disrupts the Blood-Testis Barrier via the Induction of mTOR-Dependent Autophagy in Sertoli Cells

Hepatitis B virus (HBV) is one of the most serious public health threats worldwide. HBV is not only able to pass through the blood-testis barrier (BTB); It can also cause impairment of male fertility. However, the mechanisms involved in this process remain unknown. In this study, we showed that HBV can establish persistent infection in human and mouse testes. Persistent HBV infection triggers inflammatory cell invasion, testes immune homeostasis imbalance, and the disruption of the BTB formed by inter-Sertoli cells. HBV mainly persisted in the Sertoli cells and could induce the autophagy of Sertoli cells by HBV X protein (HBx), a major regulatory protein of HBV. Data indicated that the mTOR signal pathway-mediated autophagy plays a pivotal role in HBV-induced BTB damage. Autophagy inhibitor 3-MA and mTOR activator MHY1485 could ameliorate HBV-induced autophagy and BTB damage. These findings demonstrated that the mTOR-mediated excessive autophagy of Sertoli cells induced by HBx could be one of the pathological mechanisms responsible for the fertility decline caused by HBV infection.

Effect of olanzapine on testes of adult albino rats and the possible role of granulocyte colony stimulating factor versus umbelliferone light and electron microscopic study

Olanzapine (OLZ) is one of atypical antipsychotic drugs (second generation) used for treating schizophrenia, manic, and mixed episodes of bipolar disorder. Continuous evaluation of its effects is necessary, and there is a need to explore alternative natural products as G-CSF and UMB to manage potential side effects. This research designed to mitigate the atypical antipsychotic drugs' adverse effects through biochemical analyses, light and electron microscopic studies. Fifty-six rats were divided into five groups: Control, OLZ, G-CSF, UMB, and Recovery groups. End body and testicular weights, serum testosterone, testicular MDA levels, and seminal analysis were recorded. Testicular specimens were processed to evaluate histological structure, PCNA, and CD34 immune expression. Morphometric and statistical analyses were also performed. OLZ group exhibited a distorted testicular structure, a significant increase in end body and a decline in testicular weight, a significant decline in the serum level of testosterone level, testicular MDA, and seminal analysis parameters. Furthermore, disturbed histoarchitecture, reduction in PCNA, and elevation in CD34 immunoreaction were observed. These alterations were partially attenuated by G-CSF therapy, whereas UMB significantly improved all parameters. In conclusion, UMB, and to a lesser degree G-CSF, appeared to be superior therapeutic options by attenuating oxidative stress and restoring intact histological structure and biochemical parameters.

Dendrobium huoshanense polysaccharide inhibits NSCLC proliferation and immune evasion via FXR1-IL-35 axis signaling pathway

Dendrobium huoshanense has received special attention for its advantages in the treatment of lung cancer, but the underlying molecular mechanisms are not yet well understood. First, we obtained 8 active ingredients and 159 effective action targets of Dendrobium huoshanense using network pharmacology, and searching target interactions through STRING, constructing the PPI network and KEGG, GO and Hallmark enrichment analysis. Then, we combined target's enrichment analysis and GSEA enrichment analysis of IL-35, indicating the mechanism of cDHPs for non-small cell lung cancer (NSCLC) may be related to tight junction and NSCLC pathway. Further, FXR1 and ACTR3 were identified as core therapeutic targets, and high expression of FXR1 or ACTR3 was significantly associated with poor prognosis of patients. The analysis of single-cell data also indicated that the percentage of CD4-CTLA4-Treg cells may be increased by the expression of IL-35, resulting in a suppressive immune microenvironment. Next, In vivo experiment, we detected iTr35 by flow cytometry, detected IL-35 level by RT-PCR, Western blotting and ELISA, and detected NK cell activity to explore the immunomodulatory effects and anti-tumor mechanism of cDHPs. After cDHPs administration, the conversion of CD4+ T cells to iTr35 is inhibited, p35 and EBI3 in both protein and mRNA levels, the levels of IL-35 and IL-4 in serum decreased. The levels of IFN-γ, while the activity of NK cells in mice increased, enhancing the anti-tumor immune effect of the organism. Finally, analysis of sequencing data from the immunotherapy cohort of tumor-bearing mice obtained from the TISMO database shows that the combination of cDHPs and PD-1/PD-L1 antibodies improves effector and thus PD-1/PD-L1 antibody efficacy. These findings suggest that cDHPs inhibit NSCLC proliferation and immune escape via the FXR1-IL-35 axis signaling pathway.

PPM1G dephosphorylates α-catenin to maintain the integrity of adherens junctions and regulates apoptosis in Sertoli cells

Protein phosphatase, Mg2+/Mn2+ dependent, 1G (PPM1G) regulates protein function via dephosphorylation. PPM1G participates in the assembly of adherens junctions by dephosphorylating α-catenin. Here, we demonstrated through siRNA transfection and intratesticular injection that PPM1G is critical for maintaining blood-testis barrier function and regulating Sertoli cell apoptosis. We observed that upon knocking down Ppm1g in rat testes, the function of the blood testis barrier was compromised, and the localization of α-catenin and β-catenin became aberrant. Further investigation in rat Sertoli cells revealed that after Ppm1g knockdown, the level of phosphorylated α-catenin increased, and it failed to properly aggregate at the cell membrane; instead, it was mislocalized to the cytoplasm. The actin to which catenin is attached also exhibited a disordered arrangement in the absence of PPM1G. Additionally, through RNA sequencing and bioinformatics analysis, we identified genes associated with Sertoli cell dysfunction induced by Ppm1g knockdown and identified a set of genes involved in regulating intercellular junctions. Subsequent validation revealed that after Ppm1g knockdown, the expression of the junction-related protein JAM2 was reduced, and Sertoli cells underwent apoptosis. Overall, we identified a gene, Ppm1g, which may be involved in maintaining the normal function of the blood-testis barrier and influencing the survival of Sertoli cells by regulating apoptotic pathways.

Applications of spatial transcriptomics in studying spermatogenesis

Spermatogenesis is a complex differentiation process that is facilitated by a series of cellular and molecular events. High-throughput genomics approaches, such as single-cell RNA sequencing, have begun to enable the systematic characterization of these events. However, the loss of tissue context because of tissue disassociations in the single-cell isolation protocols limits our ability to understand the regulation of spermatogenesis and how defects in spermatogenesis lead to infertility. The recent advancement of spatial transcriptomics technologies enables the studying of the molecular signatures of various cell types and their interactions in the native tissue context. In this review, we discuss how spatial transcriptomics has been leveraged to identify spatially variable genes, characterize cellular neighborhood, delineate cell‒cell communications, and detect molecular changes under pathological conditions in the mammalian testis. We believe that spatial transcriptomics, along with other emerging spatially resolved omics assays, can be utilized to further our understanding of the underlying causes of male infertility, and to facilitate the development of new treatment approaches.

Prepubertal Exposure to Tris(2-chloroethyl) Phosphate Disrupts Blood-Testis Barrier Integrity via Ferritinophagy-Mediated Ferroptosis

Tris(2-chloroethyl) phosphate (TCEP) is a representative chlorinated organophosphate flame retardant (OPFR) that demonstrates greater persistence than other non-halogenated alkyl or aryl OPFRs. Although TCEP has been shown to accumulate significantly in the environment and contribute to testicular toxicity and spermatogenic dysfunction, the precise underlying factors and mechanisms of action remain unclear. Herein, male ICR mice were gavaged with corn oil, 50 mg/kg body weight (bw) TCEP, or 100 mg/kg bw TCEP from postnatal day (PND) 22 to PND 35. TCEP exposure resulted in the disruption of blood-testis barrier (BTB) integrity and in abnormal testicular development. Considering that Sertoli cells constitute the primary target of toxicants and that TCEP induces oxidative stress in the testis and other organs, we focused on ferroptosis in Sertoli cells. Our findings revealed a significant increase in ferroptosis in the testes and Sertoli cells following TCEP exposure, and we observed functional restoration of Sertoli cell junctions upon treatment with the ferroptosis inhibitor ferrostatin-1. Furthermore, ferritin heavy chain 1 (FTH1) was markedly reduced in TCEP-exposed testes and Sertoli cells. Since nuclear receptor coactivator 4 (NCOA4)-mediated ferritinophagy is essential for the degradation of FTH1, we assessed ferritinophagic activity and found significant upregulation of NCOA4, ATG5, ATG7, and LC3B II/I in TCEP-exposed testes and Sertoli cells. These results strongly suggest that TCEP triggers Sertoli cell ferroptosis by activating ferritinophagy that leads to reduced expression of BTB-associated proteins, ultimately causing BTB disruption and testicular developmental toxicity.

Long term exposure to multiple environmental stressors induces mitochondrial dynamics imbalance in testis: Insights from metabolomics and transcriptomics

Long-term exposure to adverse environment stressors (e.g. noise pollution, temperature, and crowding) impaired human health. However, research on the toxic effects of adverse environmental stressors on the male reproductive system is limited. This study employed integrated phenomics, metabolomics, and transcriptomics to investigate physiological disturbances in the testis of mice exposed to multiple adverse environmental stressors for two months. Phenotypic studies indicated that long-term environmental stimuli resulted in significant damage to the blood-testis barrier (BTB) and testes, evidenced by reduced testicular index, disrupted testicular tissue structure, abnormal tight junction protein expression, and spermatozoa abnormalities. Comprehensive multi-omics analysis revealed that long-term exposure to environmental stressors disrupted the BTB and testes, which was associated with mitochondrial metabolism disorders, including oxidative phosphorylation and fatty acid beta-oxidation, as well as glutathione and lipid metabolism alterations. Among these dysregulated pathways, significant alterations were observed in the critical regulators of mitochondrial fusion (MFN2) and fission (DRP1) within the BTB. Specifically, corticosterone treatment decreased tight junction protein expression, increased reactive oxygen species (ROS) levels, and impaired mitochondrial morphology and function, as evidenced by reduced mitochondrial membrane potential, elevated calcium ion concentration, and shortened mitochondrial length and network in vitro. Moreover, inhibiting DRP1 with Mdivi-1 or overexpressing MFN2 mitigated the corticosterone-induced reduction of tight junctions and mitochondrial dysregulation in TM4 cells. Collectively, maintaining mitochondrial homeostasis emerges as a promising strategy to alleviate the BTB and testicular injury induced by long-term exposure to multiple environmental stressors.

Melatonin Improves Lactational Bisphenol S Induced Pre-Pubertal and Pubertal Testicular Impairments in Offspring

Lactational period is of extreme importance for nourishing and fostering growth in neonates. Bisphenol S (BPS) a congener of bisphenol A (BPA) is an emerging environmental toxicant reported to have deleterious effects on reproductive health. Indirect exposure of BPS to the suckling infants via breastmilk is less explored although it can lead to various public health issues. Therefore, we investigated harmful effects of lactational BPS exposure on pre-pubertal and pubertal testicular functions of the offspring and its possible amelioration by melatonin. Lactating dams were divided into 4 groups: control, melatonin treated (3 mg/kg BW), BPS treated (150 mg/kg BW) and BPS + melatonin co-treatment; the male offspring were evaluated at pre-pubertal (PND 22) and pubertal (PND 42) testicular developmental stages. Lactational BPS exposure affected testicular physiology, led to histological abnormalities, hormonal imbalance, alters blood-testis-barrier (E-cadherin/connexin-43), redox modulators (SIRT-1/FOXO-1/PGC-1α; Nrf2/HO-1/pSTAT-3) and germ cell dynamicity (PCNA/TUNEL positive cells) in both pre-pubertal and pubertal mice. However, melatonin supplementation to BPS exposed lactating mothers improved testicular histoarchitecture in offspring, enhanced testicular antioxidant status, modulated expression of redox/survival and BTB markers that promoted germ cell proliferation. In conclusion, our study shows that lactational BPS exposure could be deleterious to testicular physiology that may result in male infertility/subfertility in later life while melatonin supplementation improves the reproductive health compromised by lactational BPS exposure.

Concentrations of arsenic (As), cadmium (Cd) and lead (Pb) in blood, hair and semen of stallions in Finland

Heavy metal contamination poses significant environmental and health risks to both humans and animals. This study investigates the concentrations of arsenic (As), cadmium (Cd), and lead (Pb) in blood, hair, and semen samples collected from 16 breeding stallions in Western Finland to assess whether concentrations in hair and serum samples represent concentrations in semen. The analysis was conducted using an inductively coupled plasma mass spectrometry (ICP-MS) system. Results showed that hair samples exhibited the highest concentrations of heavy metals, particularly Pb and As, while semen showed the lowest levels. No significant correlations were found between the concentrations of heavy metals in blood and semen, or between hair and semen, indicating that blood and hair may not reliably predict metal content in semen. This study is the first to compare Pb, As, and Cd levels in hair, blood, and semen of Finnish stallions and highlights hair as a promising non-invasive biomarker of heavy metal exposure. The results underline hair's potential as a reliable long-term biomarker due to its ability to accumulate metals over time.

Human CSPG4-targeting CAR-macrophages inhibit melanoma growth

Approximately half of melanoma patients relapse or fail to respond to current standards of care, highlighting the need for new treatment options. Engineering T-cells with chimeric antigen receptors (CARs) has revolutionized the treatment of hematological malignancies but has been clinically less effective in solid tumors. We therefore sought to engineer alternative immune cell types to inhibit melanoma progression. Engineering macrophages with CARs has emerged as a promising approach to overcome some of the challenges faced by CAR-T cells; however, whether these engineered macrophages can effectively inhibit melanoma growth is unknown. To determine whether CAR-macrophages (CAR-Ms) specifically target and kill melanoma cells, we engineered CAR-Ms targeting chondroitin sulfate proteoglycan 4 (CSPG4), an antigen expressed in melanoma. CSPG4-targeting CAR-Ms exhibited specific phagocytosis of CSPG4-expressing melanoma cells. We developed 3D approaches to show that CSPG4-targeting CAR-Ms efficiently infiltrated melanoma spheroids. Furthermore, combining CSPG4-targeting CAR-Ms with strategies inhibiting CD47/SIRPα "don't eat me" signaling synergistically enhanced CAR-M-mediated phagocytosis and robustly inhibited melanoma spheroid growth in 3D. Importantly, CSPG4-targeting CAR-Ms inhibited melanoma tumor growth in mouse models. These results suggest engineering macrophages against melanoma antigens is a promising solid tumor immunotherapy approach for treating melanoma.

Cytotoxicity of methamphetamine exposure on Sertoli cells: a pilot study with implications for male infertility

Methamphetamine (Meth), a psychoactive drug, has been shown to reduce testicular weight and decrease sperm count, indicating its potential role in contributing to male infertility. We therefore assessed Meth's effects (0.1-100 μM) on TM4 Sertoli cell viability, toxicity, and proliferation (trypan blue exclusion assay), mitochondrial activity (MA) (XTT assay), while transepithelial electrical resistance (TEER) was used to examine monolayer permeability. The acute study (only 24-hour Meth exposure) mimics recreational users and the chronic study, the Meth addicts who require daily doses (24-96 hours). Acute Meth treatment had minimal impact on TM4 Sertoli cell viability and toxicity, while chronic exposure resulted in reduced cell viability and increased toxicity in a dose-related manner. Acute exposure suppressed cell division at 72 hours, while chronic exposure suppressed cell division at both 72 and 96 hours. Long-term suppression of MA was observed for both acute and chronic Meth exposure (20 µM and 100 µM). Both acute and chronic Meth exposure affected permeability across the blood-testis barrier (BTB), which persisted for up to 96 hours. Given the pivotal role of Sertoli cells in spermatogenesis, our findings provide a two-pronged mechanism for Meth-induced male infertility and indicate that short-term exposure may have long-term effects on the germinal epithelium.

Benzyl butyl phthalate promotes ferroptosis in Sertoli cells via disrupting ceruloplasmin-mediated iron balance

Widespread environmental contamination with benzyl butyl phthalate (BBP) has raised concerns due to its high potential for bioaccumulation and male reproductive toxicity. However, the mechanisms underlying BBP-induced male reproductive damage remain unclear. As the adjacent Sertoli cell-formed blood-testis barrier (BTB) creates a privileged niche for spermatogenesis and may serve as the first target of reproductive toxicants, we mainly focused on the detrimental effect of BBP on Sertoli cells and the BTB in this study. C57BL/6 mice were administered BBP via oral gavage at doses ranging from 0 to 400 mg/kg/day for 60 consecutive days. A comprehensive investigation was performed to estimate testicular BBP levels, sperm parameters, histological alterations, functional permeability of the Sertoli cell-based BTB, and ferroptosis in mice. Isolated Sertoli cells were further used to explore and validate the role of ferroptosis in BBP-induced BTB disruption. The results showed that permeation of BBP into the testis induced reduction in sperm quantity and quality, accompanied by fractured BTB ultrastructure, compromised permeable 'fence' functions of BTB, decreased expressions of tight junction proteins (TJP1 and OCLN) and paracellular transepithelial electrical resistance (TER) of Sertoli cells. Moreover, BBP exposure significantly increased intracellular iron content, promoted lipid peroxidation, and activated ferroptosis in the testis of mice and primary Sertoli cells, which was involved in BBP-induced disruption of BTB integrity and function as confirmed by the ferroptosis inhibitors. In mechanism, BBP specifically downregulated the intracellular iron exporter ceruloplasmin (CP) level to inhibit Fe2+ export and the oxidization of Fe2+ into less toxic Fe3+, thus exacerbating ferroptosis in Sertoli cells. Overexpression of CP significantly suppressed ferroptosis and alleviated BBP-induced BTB disruption. These findings reveal the role of CP-mediated iron homeostasis in regulating Sertoli cell ferroptosis and BTB function, providing new insights into the mechanisms of BBP-related reproductive toxicity.

Perfluorohexane Sulfonic Acid Disrupts the Immune Microenvironment for Spermatogenesis by Damaging the Structure of the Blood-Testis Barrier in Mice

Perfluorohexane sulfonic acid (PFHxS) is extensively used in waterproof coatings and fire-fighting foams, and several studies have found it to be a potential health hazard, but there is still unknown about its effects on spermatogenesis. Our results showed that PFHxS-treated mice have significant reproductive toxicity, including a decrease in sperm count and motility, and the levels of sex hormones (P < 0.05). Concurrently, structural abnormalities are observed in sperm, affecting ≈60-75% of those in the PFHxS-treated group. Additionally, it is found that the structure of the blood-testis barrier (BTB) is damaged after PFHxS treatment, leading to higher expression levels of inflammatory cytokines in the microenvironment for spermatogenesis. Moreover, the expression of proteins associated with mitochondrial biogenesis, including PTEN-induced kinase 1 (PINK1) and NADPH oxidase 4 (NOX4), is dysregulated in the testes after PFHxS treatment. Based on metabolome data, the differential metabolite 3-hydroxybutanoic acid is identified in the PFHxS-treated group, which can regulate the histone Kac levels, especially H3K4ac and H3K9ac. In summary, the results of this study suggest that in the testes of PFHxS-treated mice, inflammatory factors disrupt the mitochondrial function and metabolic profiles and hinder the progress of gene transcription through histone Kac, ultimately causing sperm dysfunction.

Mitochondrial ROS-associated integrated stress response is involved in arsenic-induced blood-testis barrier disruption and protective effect of melatonin

Arsenic (As) is an environmental metalloid. Previous studies have demonstrated that As exposure resulted in decline of sperm quality. This study aimed to investigate the impact of exposure to As on blood-testis barrier (BTB) in a mouse model. Four-week-old male mice were exposed to NaAsO2 (1 or 15 mg/L) for 6 weeks. Our results found that NaAsO2 exposure disrupted the BTB and reduced sperm counts in adult mice. NaAsO2 activated the integrated stress response (ISR) and downregulated barrier junction protein in mouse testes and Sertoli cells. Ribosome profiling sequencing (Ribo-seq) and Ribosome-nascent chain complex-bound mRNA qPCR (RNC-qPCR) showed that translational efficiency of N-cadherin and ZO-1, two key barrier junction proteins, was reduced in NaAsO2-treated Sertoli cells. Mechanistically, NaAsO2 exposure reduced SIRT3 protein via proteasomal degradation, thereby resulting in mitochondrial dysfunction and excess mitochondrial ROS (mtROS) generation in Sertoli cells. Melatonin alleviated NaAsO2-induced mitochondrial dysfunction and mtROS upregulation via reducing SOD2 acetylation in Sertoli cells. Moreover, melatonin antagonized NaAsO2-induced ISR, barrier junction proteins downregulation and barrier function impairment in Sertoli cells. Accordingly, melatonin attenuated NaAsO2-evoked BTB disruption and sperm count reduction in adult mice. These results suggest that mitochondrial dysfunction-associated translational inhibition of barrier junction proteins is involved in As-mediated BTB disruption and sperm quality decline.

Roles of thyroid and leptin hormones and their crosstalk in male reproductive functions: an updated review

PURPOSE

This review aims to provide updated information regarding the role of thyroid and leptin hormones and their crosstalk in affecting the male reproductive function in hypothyroid and obesity conditions.

METHOD

A wide literature search was made using online search engines on published articles using keywords including thyroid hormone, hypothyroidism, leptin hormone, hyperleptinemia, obesity, the relationship between thyroid and leptin hormones and male reproduction, and hypothyroidism, obesity, and male reproduction.

RESULTS

All information pertaining thyroid and leptin hormone effects on male reproduction, hypothyroidism, hyperleptinemia, and obesity effect on male fertility as well as the related molecular mechanisms are obtained.

CONCLUSION

Thyroid and leptin hormones individually play a significant role in male reproduction. Alterations of these hormones' levels could adversely affect the male reproductive functions. PI3K/AKT signaling was found to be the major signaling pathway involved in mediating the effect of both hormones on male reproduction. Impaired crosstalk between the two hormones may occur in hypothyroidism with obesity which would contribute towards male reproductive dysfunction.

Quaternary ammonium compound exposure causes infertility by altering endocrine signaling and gametogenesis

Quaternary ammonium compounds (QACs) are common substances utilized in cleaners, ophthalmic solutions, swimming pool treatments, cosmetics, and other consumer goods. Previous studies have shown that QAC exposure causes infertility in both male and female mice. Based on these studies, we hypothesized that oral QAC exposure negatively impacts male and female reproduction through changes in physiologic and endocrine mechanisms rather than direct toxicity to gametes. Endocrine disruption was assessed by evaluating luteinizing hormone (LH) and follicle stimulating hormone (FSH) concentrations in male and female mice exposed orally throughout gestation and lactation, and by changes in estrogen and progesterone in in orally exposed females throughout pregnancy. Sperm functionality and spermatogenesis were assessed by in vitro fertilization; while Sertoli cell homeostasis was evaluated by determining cellular metabolism, cell cycle progression and blood-testes barrier (BTB) permeability. QAC exposure decreased LH, and FSH concentrations in both males and females, and decreased progesterone and estrogen concentrations during pregnancy. QACs significantly decreased Sertoli cell metabolism at 0.0005 % ADBAC+DDAC well before disruption of the BTB at 0.01 %. Fertilization was not affected 24 h after exposure but was decreased after a 10 day rest period suggesting a disruption in spermatogenesis rather than direct toxicity to sperm. Lastly, QAC exposure altered Sertoli cell cycling with a G2/M cycle arrest. While the effect of QAC exposure on humans is unknown, implications from the in vivo and in vitro studies are concerning given the rise in infertility rates and increased reliance on assisted reproductive technologies along with ubiquitous exposure to QACs.

Prospect of extracellular vesicles in tumor immunotherapy

Extracellular vesicles (EVs), as cell-derived small vesicles, facilitate intercellular communication within the tumor microenvironment (TME) by transporting biomolecules. EVs from different sources have varied contents, demonstrating differentiated functions that can either promote or inhibit cancer progression. Thus, regulating the formation, secretion, and intake of EVs becomes a new strategy for cancer intervention. Advancements in EV isolation techniques have spurred interest in EV-based therapies, particularly for tumor immunotherapy. This review explores the multifaceted functions of EVs from various sources in tumor immunotherapy, highlighting their potential in cancer vaccines and adoptive cell therapy. Furthermore, we explore the potential of EVs as nanoparticle delivery systems in tumor immunotherapy. Finally, we discuss the current state of EVs in clinical settings and future directions, aiming to provide crucial information to advance the development and clinical application of EVs for cancer treatment.

Dynamic changes in histone lysine lactylation during meiosis prophase I in mouse spermatogenesis

Male germ cells, which are responsible for producing millions of genetically diverse sperm through meiosis in the testis, rely on lactate as their central energy metabolite. Recent study has revealed that lactate induces epigenetic modification in cells through histone lysine lactylation. Here, we report dynamic histone lactylation at histone H4-lysine 5 (K5), -K8, and -K12 during meiosis prophase I in mouse spermatogenesis. By profiling the genome-wide occupancy of histone H4-K8 lactylation (H4K8la), which peaks at zygotene, our data show that H4K8la mark is observed at the promoters of genes exhibiting active expression with Gene Ontology functions enriched for meiosis. Notably, our data also demonstrate that H4K8la is closely associated with recombination hotspots, where machinery involved in the processing DNA double-stranded breaks, such as SPO11, DMC1, RAD51, and RPA2, is engaged. In addition, H4K8la was also detected at the meiosis-specific cohesion sites (marked by RAD21L and REC8) flanking the recombination hotspots. Functionally, our data show that lactate induces upregulation of key meiotic genes through H4K8la modifications. Additionally, H4K8la shows colocalization and interaction with PRDM9 at recombination hotspots. Finally, our data show that HBO1, a lactyltransferase, is highly expressed in meiotic germ cells. In vitro lactylation assays reveal that HBO1 induces H4K8la, and pharmacological inhibition of HBO1 in mice reduces H4K8la levels and disrupts meiosis. Collectively, our findings suggest that histone lactylation serves as an epigenetic mechanism that is involved in meiotic gene expression and recombination in male germ cells during spermatogenesis.

Inactivation of JNK signalling results in polarity loss and cell senescence of Sertoli cell

As major somatic cells in the testis, Sertoli cell development is precisely regulated by numerous factors, and aberrant development of these cells is associated with male reproductive diseases. JNK signalling is evolutionarily conserved and involved in multiple critical biological processes. Here, we found that the double knockout of Jnk1 and Jnk2 resulted in aberrant localisation of Sertoli cells at early developmental stages, with most Sertoli cells being lost at later stages. Further studies revealed that the inactivation of JNK signalling caused polarity loss in Sertoli cells. In vitro-cultured Jnk1/2-DKO Sertoli cells exhibited a senescence-associated phenotype. Mechanistic studies demonstrate that JNK signalling is likely involved in establishing Sertoli cell polarity by regulating the expression of TGF-β2, mediated by c-Jun. The senescence of Sertoli cells in JNKs-deficient mice is caused by aberrant proteolysis of P27KIP1, mediated by c-Myc. This study demonstrates the role of JNK signalling in Sertoli cell development and functional maintenance, which may also represent an aetiology of male infertility in humans.

The impact of mercury exposure on male reproduction: Mechanistic insights

Mercury is a pervasive environmental toxin with significant negative effects on human health. In occupational settings, incidents such as the Minamata and Niigata disease in Japan and the large-scale methylmercury poisoning in Iraq have highlighted the severe health impacts of mercury exposure. It is widely accepted that all forms of mercury including methylmercury and mercuric chloride have the potential to induce toxic effects in mammals, and there is increasing concern about the impact of environmentally relevant levels of mercury on reproductive functions. This review summarizes current knowledge on the mechanisms of mercury toxicity, focusing specifically on its impact on male reproductive health across species. We searched the literature and found that mercury exposure is associated with testicular degeneration, altered spermatogenesis, and Leydig cell deformation. In addition, mercury can disrupt sperm motility, steroidogenesis and interfere with the hypothalamic-pituitary-gonadal axis by generation of reactive oxygen species, inducing mitochondrial dysfunction, epigenetic changes, and DNA damage. At the molecular level, mercury has been found to dysregulate the expression of key steroidogenic and spermatogenic genes, significantly reducing overall fertility potential. However, specific mechanisms of action remain to be fully elucidated. Similarly, comprehensive data on the potential transgenerational effects of paternal mercury exposure are lacking. In this review, we discuss both animal and human studies, and highlight the need for further research due to lack of standardization and control for variables such as lifestyle, immune system function, and exposure concentrations.

Unraveling the genetic basis of azoospermia: transcriptome profiling analyses in a Greek population

OBJECTIVE

To investigate whether idiopathic nonobstructive azoospermia (iNOA) has its own transcriptomic signature.

DESIGN

Testicular tissue biopsies were retrieved, processed, and prepared for ribonucleic acid (RNA) extraction from 26 consented patients diagnosed with iNOA. Samples were grouped into four pools based on the presence of testicular spermatozoa: two replicate pools for "No presence" (Null-spz-1 and Null-spz-2 pools), one for "High presence" (High-spz pool), and one for "Rare presence" (Rare-spz pool). A second set of replicate pools (CF-1 and CF-2) were used from patients with obstructive azoospermia (OA) and served as controls. RNA sequencing (RNA-seq) and comparative transcriptomics analysis were performed, followed by differential gene expression analysis focused on protein-coding genes only. Differentially expressed genes (DEGs) exclusively upregulated or downregulated were further analyzed using the Gene Ontology (GO), STRING, and Kyoto Encyclopedia of Genes and Genome bioinformatic platforms.

SUBJECTS

Males in whom iNOA was diagnosed.

EXPOSURE

Testicular biopsies from men in whom iNOA was diagnosed.

MAIN OUTCOME MEASURES

Protein-coding DEGs.

RESULTS

A significantly altered transcriptomic profile of protein-coding genes was identified in the testicular tissues from men with iNOA. A total of 3,858 genes exhibited dysregulated expression, with 1,994 genes being exclusively downregulated and 1,734 upregulated. Biological processes such as male gamete generation (GO:0048232) and meiotic cycle (GO:0051321) were significantly enriched by the downregulated DEGs whereas the upregulated DEGs enriched BPs such as regulation of cell death (GO:0010941), regulation of cell adhesion (GO:0030155), and defense response (GO:0006952). Interactome analysis identified hub genes among the downregulated DEGs, including PCNA, PLK1, MCM4, CDK1, CCNB1, AURKA, CCNA2, and CDC6, and among the upregulated DEGs, including EGFR, RELA, CTNNB1, MYC, JUN, SMAD3, STAT3 NFKB1, TGFB1, and ACTB. In addition, Kyoto Encyclopedia of Genes and Genome analysis demonstrated that pathways such as cell cycle (hsa04110) and oocyte meiosis (hsa04114) are primarily affected by the downregulated genes, whereas the upregulated genes mainly affected pathways such as the focal adhesion (hsa04510) and the PI3-Akt signaling pathway (hsa04151).

CONCLUSION

A distinct messenger RNA expression profile and altered transcriptomic activity were identified in the testicular tissues of men with iNOA.

CLINICAL TRIAL REGISTRATION NUMBER

University of Thessaly 1, 15.04.2016 and the Greek National Authority 701/15.9.2017.

Exploring the Characters of Non-Coding RNAs in Spermatogenesis and Male Infertility

Infertility is a widespread clinical problem that affects human reproduction and species persistence worldwide. Around 40-70% of cases are due to male reproductive defects. Functional spermatogenesis (sperm production through several coordinated events) is at the heart of male fertility. Non-coding RNAs (ncRNAs) are the primary regulators of gene expression, controlling extensive critical cellular processes, for example proliferation, differentiation, apoptosis, and reproduction. Due to advancements in high-throughput sequencing tools, many studies have revealed that ncRNAs are widely expressed in germ cells, meiosis, spermatogenesis, sperm fertility, early post-fertilization development, and male infertility. The present review examines the biology and function of ncRNAs, including microRNAs, circular RNAs, and long ncRNAs, in spermatogenesis, their correlation with infertility, and their potential as biomarkers for sperm quality and fertility. The function of ncRNA in Sertoli cells (SCs) and Leydig cells (LCs) is also outlined throughout this study, because spermatogenesis requires testicular somatic cells to be involved in testicular development and male fertility. Meanwhile, the future development of ncRNAs for the clinical treatment of male infertility is also anticipated and discussed.

Construction of human pluripotent stem cell-derived testicular organoids and their use as humanized testis models for evaluating the effects of semaglutide

Background: The generation of human testicular organoids from human induced pluripotent stem cells (hiPSCs) presents exciting opportunities for gonadal developmental biology, and reproductive disease modeling. However, creating organoids that closely mimic the tissue structure of testes remains challenging. Methods: In this study, we established a method for generating testicular organoids (TOs) from hiPSCs using a stepwise differentiation approach and a combination of hanging drop and rotational culture systems. The capability of hiPSC-derived precursor testicular cells to self-assemble into organoids was confirmed by detection of morphology, single-cell RNA-sequencing, and protein profiles. The reliability of testicular organoids as a drug evaluation model was assessed by the measurements of transcriptome signatures and functional features, including hormone responsiveness and blood-testis barrier (BTB) formation, and drug sensitivity assessment by recording cell viability and BTB integrity in organoids exposed to reproductive toxicants. Finally, we applied testicular organoids to evaluate the effects of semaglutide, a glucagon-like peptide-1 receptor agonist (GLP-1 RA), on testicular function, thereby underscoring their utility as a model for drug evaluation. Results: These organoids exhibited testicular cord-like structures and BTB function. RNA sequencing and functional assays confirmed that testicular organoids possess gene expression profiles and endocrine functions regulated by gonadotropins, closely resembling those of testicular tissue. Notably, these organoids displayed sensitivity to semaglutide. Treatment with semaglutide resulted in reduced testosterone levels and downregulation of INHBB expression, aligning with previous clinical observations. Conclusions: These findings introduced a method for generating testicular organoids from human pluripotent stem cells, highlighting their potential as valuable models for studying testicular function, drug toxicity, and the effects of compounds like semaglutide on testicular health.

Identification of novel cytoskeleton protein involved in spermatogenic cells and sertoli cells of non-obstructive azoospermia based on microarray and bioinformatics analysis

BACKGROUND

During mammalian spermatogenesis, the cytoskeleton system plays a significant role in morphological changes. Male infertility such as non-obstructive azoospermia (NOA) might be explained by studies of the cytoskeletal system during spermatogenesis.

METHODS

The cytoskeleton, scaffold, and actin-binding genes were analyzed by microarray and bioinformatics (771 spermatogenic cellsgenes and 774 Sertoli cell genes). To validate these findings, we cross-referenced our results with data from a single-cell genomics database.

RESULTS

In the microarray analyses of three human cases with different NOA spermatogenic cells, the expression of TBL3, MAGEA8, KRTAP3-2, KRT35, VCAN, MYO19, FBLN2, SH3RF1, ACTR3B, STRC, THBS4, and CTNND2 were upregulated, while expression of NTN1, ITGA1, GJB1, CAPZA1, SEPTIN8, and GOLGA6L6 were downregulated. There was an increase in KIRREL3, TTLL9, GJA1, ASB1, and RGPD5 expression in the Sertoli cells of three human cases with NOA, whereas expression of DES, EPB41L2, KCTD13, KLHL8, TRIOBP, ECM2, DVL3, ARMC10, KIF23, SNX4, KLHL12, PACSIN2, ANLN, WDR90, STMN1, CYTSA, and LTBP3 were downregulated. A combined analysis of Gene Ontology (GO) and STRING, were used to predict proteins' molecular interactions and then to recognize master pathways. Functional enrichment analysis showed that the biological process (BP) mitotic cytokinesis, cytoskeleton-dependent cytokinesis, and positive regulation of cell-substrate adhesion were significantly associated with differentially expressed genes (DEGs) in spermatogenic cells. Moleculare function (MF) of DEGs that were up/down regulated, it was found that tubulin bindings, gap junction channels, and tripeptide transmembrane transport were more significant in our analysis. An analysis of GO enrichment findings of Sertoli cells showed BP and MF to be common DEGs. Cell-cell junction assembly, cell-matrix adhesion, and regulation of SNARE complex assembly were significantly correlated with common DEGs for BP. In the study of MF, U3 snoRNA binding, and cadherin binding were significantly associated with common DEGs.

CONCLUSION

Our analysis, leveraging single-cell data, substantiated our findings, demonstrating significant alterations in gene expression patterns.

Site-specific DNA demethylation during spermatogenesis presets the sites of nucleosome retention in mouse sperm

DNA methylation patterns are inherited from the parental germline to the embryo. In mature sperm, the sites of unmethylated DNA are tightly coupled to sites of histone retention at gene regulatory elements that are implicated in paternal epigenetic inheritance. The timing and mechanism of site-specific DNA demethylation in the male germline currently remains unknown. Here, we perform genome-wide profiling of DNA methylation during spermatogenesis by capturing methylated DNA through interaction with a methyl-DNA binding protein domain (MBD). Our data demonstrate that there is a site-specific change in DNA methylation during the mitosis-to-meiosis transition. Importantly, the genomic sites that are demethylated during this transition predetermine nucleosome retention sites in spermatozoa. These results suggest that site-specific DNA demethylation during the mitosis-to-meiosis transition of spermatogenesis prepares embryonic gene expression after fertilization. We therefore propose DNA demethylation during spermatogenesis as a novel phase of epigenetic reprogramming that contributes to embryonic gene regulation.

The role of leptin in the male reproductive system

Leptin is a hormone produced from adipose tissue, targeting the hypothalamus and regulating energy expenditure, adipose tissue mass, and reproductive function. Leptin concentration reflects body weight and the amount of energy stored, as well as the level of reproductive hormones and male fertility. In this review, the aim was to focus on leptin signaling mechanisms and the significant influence of leptin on the male reproductive system and to summarize the current knowledge of clinical and experimental studies. The PubMed database was searched for studies on leptin and the male reproductive system to summarize the mechanism of leptin in the male reproductive system. Studies have shown that obesity-related, high leptin levels or leptin resistance negatively affects male reproductive functions. Leptin directly affects the testis by binding to the hypothalamic-pituitary-gonadal axis and the receptors of testicular cells, and thus the location of leptin receptors plays a key role in the regulation of the male reproductive system with the negative feedback mechanism between adipose tissue and hypothalamus. Based on the current evidence, leptin may totally inhibit male reproduction, and investigation of this role of leptin has established a potential interaction between obesity and male infertility. The mechanism of leptin in the male reproductive system should be further investigated and possible treatments for subfertility should be evaluated, supported by better understanding of leptin and associated signaling mechanisms.

Riluzole Reverses Blood-Testis Barrier Loss to Rescue Chemotherapy-Induced Male Infertility by Binding to TRPC

Cancer treatments, including cytotoxic therapy, often result in male infertility, necessitating the development of safe and effective strategies to preserve male reproductive potential during chemotherapy. Notably, our study uncovers the potential of repurposing riluzole, an FDA-approved drug for amyotrophic lateral sclerosis (ALS), in enhancing spermatogenesis. Hence, this research aims to explore the feasibility of utilizing riluzole to alleviate male infertility induced by busulfan (BSF), a commonly used chemotherapy drug. We established a BSF-induced oligospermia model in 4-week-old male mice and found that riluzole could effectively counter the detrimental effects of BSF on sperm production in mice with oligospermia. By restoring blood-testis barrier (BTB) functionality, riluzole improves sperm quality and reduces testicular atrophy. Through transcriptomic and molecular docking analyses, we identify transient receptor potential canonical subfamily member 5 (TRPC5) as a potential target for riluzole-mediated regulation of blood-testis barrier function. These findings propose riluzole as a promising therapeutic option for chemotherapy-induced male infertility, thereby addressing the fertility challenges associated with cancer treatments. Moreover, repurposing riluzole could streamline the drug development process, providing a cost-effective approach with reduced risk compared to developing entirely new drugs.

Testicular immunity

The testis is a unique environment where immune responses are suppressed to allow the development of sperm that possess autoimmunogenic antigens. There are several contributors responsible for testicular immune privilege, including the blood-testis barrier, testicular immune cells, immunomodulation by Sertoli cells, and high levels of steroid hormones. Despite multiple mechanisms in place to regulate the testicular immune environment, pathogens that disrupt testicular immunity can lead to long-term effects such as infertility. If testicular immunity is disturbed, autoimmune reactions can also occur, leading to aberrant immune cell infiltration and subsequent attack of autoimmunogenic germ cells. Here we discuss cellular and molecular factors underlying testicular immunity and how testicular infection or autoimmunity compromise immune privilege. We also describe infections and autoimmune diseases that impact the testis. Further research into testicular immunity will reveal how male fertility is maintained and will help update therapeutic strategies for infertility and other testicular disorders.

Porcine reproductive and respiratory syndrome virus infects the reproductive system of male piglets and impairs development of the blood-testis barrier

Porcine reproductive and respiratory syndrome virus (PRRSV) causes a highly contagious disease that threatens the global swine industry. Recent studies have focused on the damage that PRRSV causes to the reproductive system of male pigs, although pathological research is lacking. Therefore, we examined the pathogenic mechanisms in male piglets infected with PRRSV. Gross and histopathological changes indicated that PRRSV affected the entire reproductive system, as confirmed via immunohistochemical analysis. PRRSV infected Sertoli cells and spermatogonia. To test the new hypothesis that PRRSV infection in piglets impairs blood - testis barrier (BTB) development, we investigated the pathology of PRRSV damage in the BTB. PRRSV infection significantly decreased the quantity and proliferative capacity of Sertoli cells constituting the BTB. Zonula occludens-1 and β-catenin were downregulated in cell - cell junctions. Transcriptome analysis revealed that several crucial genes and signalling pathways involved in the growth and development of Leydig cells, Sertoli cells, and tight junctions in the testes were downregulated. Apoptosis, necroptosis, inflammatory, and oxidative stress-related pathways were activated, whereas hormone secretion-related pathways were inhibited. Many Sertoli cells and spermatogonia underwent apoptosis during early differentiation. Infected piglets exhibited disrupted androgen secretion, leading to significantly reduced testosterone and anti-Müllerian hormone levels. A cytokine storm occurred, notably upregulating cytokines such as tumour necrosis factor-α and interleukin-6. Markers of oxidative-stress damage (i.e. H2O2, malondialdehyde, and glutathione) were upregulated, whereas antioxidant-enzyme activities (i.e. superoxide dismutase, total antioxidant capacity, and catalase) were downregulated. Our results demonstrated that PRRSV infected multiple organs in the male reproductive system, which impaired growth in the BTB.

Impact of Oxidative Stress on Sperm Quality in Oligozoospermia and Normozoospermia Males Without Obvious Causes of Infertility

Background: Male factors contribute to approximately 50% of infertile couples. However, obvious causes remain unknown in many cases. This observational study aimed to investigate the associations of clinical and lifestyle parameters with sperm parameters. Methods: This study enrolled 41 men in infertile couples without obvious causes for male infertility from July 2023 to April 2024. Semen samples were evaluated for sperm number, motility, DNA fragmentation, and oxidative stress (OS) marker oxidation-reduction potential (ORP). Blood samples were analyzed for biochemical parameters, including advanced glycation end products (AGEs), and systemic OS marker diacron-reactive oxygen metabolites (d-ROMs). Skin-accumulated AGE levels were identified with an autofluorescence method. Lifestyle factors were assessed with a lifestyle questionnaire. Results: Most of the participants were under 40 years old and non-obese with normal clinical parameters. Multiple regression analyses revealed that body mass index, serum d-ROMs, and semen ORP levels were independently associated with decreased sperm number. Additionally, serum zinc and semen ORP levels were associated with sperm motility. Furthermore, serum zinc and high-density lipoprotein cholesterol levels were associated with sperm progressive motility and DNA fragmentation, respectively. The rest of the clinical and lifestyle factors, including skin-accumulated and serum AGE levels, were not correlated with any sperm parameters. Furthermore, serum d-ROM and semen ORP levels were not correlated with each other or any of the clinical and lifestyle factors. Conclusions: Our present study indicates that both systemic and local OS may be independently involved in sperm abnormality in healthy men without obvious causes for male infertility.

Protective Effects of L-Cysteine Against Cisplatin-Induced Oxidative Stress-Mediated Reproductive Damage

Cisplatin (CIS) is a widely used chemotherapeutic agent, but its side effects, such as oxidative stress, inflammation, and apoptosis, often lead to male reproductive damage. Oxidative stress, primarily caused by the excessive generation of reactive oxygen species (ROS), plays a critical role in disrupting testicular homeostasis, resulting in spermatogenic impairment and tissue injury. L-cysteine (CYS), a semi-essential amino acid with potent antioxidant and anti-inflammatory properties, may offer protection against CIS-induced oxidative damage. This study aimed to assess the protective potential of CYS against CIS-induced male reproductive toxicity using in vivo and in vitro models. In vitro, treatment of TM3 (Leydig) and TM4 (Sertoli) cells with CIS led to increased ROS levels, reduced cell viability, and elevated apoptosis and inflammation, all of which were significantly ameliorated by subsequent CYS exposure. In vivo, CIS-treated male rats displayed heightened oxidative stress, impaired spermatogenesis, and histopathological damage in reproductive organs. However, CYS administration for 21 days significantly reduced oxidative stress, improved sperm viability, and protected testicular tissues from damage. These findings suggest that CYS has a protective effect against CIS-induced oxidative stress and male reproductive damage, making it a promising therapeutic agent for mitigating CIS-induced reproductive toxicity.

Orange peel ethanolic extract and physical exercise prevent testicular toxicity in streptozocin and high fat diet-induced type 2 diabetes rats via Nrf2/NF-kB signaling: In silico and in vivo studies

Background

Type 2 diabetes mellitus (T2DM) is a significant health issue affecting the quality of life including male reproductive functions. Orange peel ethanolic extract (OPEE) has been established to have antioxidant properties and has been shown to alleviate diabetic complications. This study determined to establish OPEE effect and physical exercise (EX) in T2DM-induced testicular dysfunction.

Materials and methods

Thirty male Wistar rats were randomly distributed in five groups as follows: control group (received 1 ml/b.w of normal saline), and groups 2-5 were induced with diabetes, with group 2 left untreated, group 3 received 600 mg/kg b.w OPEE, group 4 was subjected to EX while group 5 was treated with OPEE alongside EX.

Results

OPEE + EX ameliorated T2DM-induced decrease in sperm motility, count, and morphology and increased testicular lactate dehydrogenase, alkaline phosphate, gamma-glutamyl transferase, and lactate. T2DM-induced disruption of gonadotropin-releasing hormone, luteinizing hormone, follicle-stimulating hormone and, testosterone was also mitigated by OPEE + EX. In addition, OPEE + EX blunted T2DM-induced increase in oxidative stress, inflammatory, and apoptotic markers and the accompanied decrease in testicular nuclear factor erythroid 2-related factor 2 (Nrf2) and increase in nuclear factor kappa B (NF-κB). Also, OPEE + EX reversed T2DM-induced testicular histology distortion.

Conclusions

The outcome of this study revealed that the combination of OPEE and EX ameliorated T2DM-mediated testicular damage via Nrf2/NF-κB signaling.

Chronic dietary exposure to glyphosate-induced connexin 43 autophagic degradation contributes to blood-testis barrier disruption in roosters

Glyphosate (GLY) is the most universally used herbicide worldwide and its application has caused extensive pollution to the ecological environment. Increasing evidence has revealed the multi-organ toxicity of GLY in different species, but its male reproductive toxicity in avian species remains unknown. Thus, in vivo and in vitro studies were conducted to clarify this issue. Data firstly showed that chronic GLY exposure caused testicular pathological damage. Intriguingly, we identified and verified a marked down-regulation gap junction gene Connexin 43 (Cx43) in GLY-exposed rooster testis by transcriptome analysis. Cx43 generated by Sertoli cells acts as a key component of blood-testis barrier (BTB). To further investigate the cause of GLY-induced downregulation of Cx43 to disrupt BTB, we found that autophagy activation is revealed in GLY-exposed rooster testis and primary avian Sertoli cells. Moreover, GLY-induced Cx43 downregulation was significantly alleviated by ATG5 knockdown or CQ administration, respectively, demonstrating that GLY-induced autophagy activation contributed to Cx43 degradation. Mechanistically, GLY-induced autophagy activation and resultant Cx43 degradation was due to its direct interaction with ER-α. In summary, these findings demonstrate that chronic GLY exposure activates autophagy to induce Cx43 degradation, which causes BTB damage and resultant reproductive toxicity in roosters.

Vangl2 regulates intercellular junctions by remodeling actin-based cytoskeleton through the Rock signaling pathway during spermatogenesis in Eriocheir sinensis

As a key planar cell polarity protein, Van Gogh-like 2 (Vangl2) is essential for mammalian spermatogenesis. As a decapod crustacean, Eriocheir sinensis exhibits distinct spermatogenic processes due to its unique seminiferous tubule morphology and hemolymph-testis barrier (HTB). To determine whether Vangl2 performs analogous functions in E. sinensis, we identified the Es-Vangl2. Es-Vangl2 exhibited high expression and wide distribution in the testes, indicating its crucial involvement in spermatogenesis. Following targeted knockdown of Es-Vangl2in vivo, the structure of seminiferous tubules was disrupted, characterized by vacuolization of the germinal zone and obstruction of spermatozoon release. Concurrently, the integrity of the HTB was compromised, accompanied by reduced expression and aberrant localization of junction proteins. More importantly, the regulatory influence of Es-Vangl2 was manifested through modulating the organization of microfilaments, a process mediated by epidermal growth factor receptor pathway substrate 8 (Eps8). Further studies demonstrated that these phenotypes resulting from Es-Vangl2 knockdown were attributed to the inhibition of Rock signaling pathway activity, which was verified by the Es-Rock interference and Y27632 inhibition assays. In summary, the findings highlight the pivotal role of Es-Vangl2 in stabilizing HTB integrity by regulating Eps8-mediated actin remodeling through the Rock signaling pathway in the spermatogenesis of E. sinensis.

The Gut Microbiota Contributes to the Development of LPS-Induced Orchitis by Disrupting the Blood-Testosterone Barrier in Mice

Orchitis is a frequent inflammatory reproductive disease that causes male infertility and a decline in sperm quality. Gut microbiota can regulate systemic and local inflammation, spermatogenesis and blood-testosterone barrier (BTB). In this study, we investigated correlation between gut microbiota and orchitis by establishing a mouse gut microbiota imbalance model induced by antibiotics (ABX) treatment and orchitis model induced by lipopolysaccharide (LPS) infection. Based on these two models, 16s rRNA sequencing and feces microbiota transplantation (FMT) experiments were combined to examine the function and regulatory mechanisms of the gut microbiota in host defense against orchitis. Compared with control mice, gut microbiota imbalance resulted in increasing inflammatory responses, modulating oxidative stress related enzyme activity, testosterone levels and the permeability of blood testosterone barrier, which are restored after FMT. Subsequently, we tested the relationship between the gut microbiota imbalance and testicular inflammation severity in orchitis. It was found that the ABX and LPS co-treated mice had more severe inflammatory responses, lower testosterone levels and greater permeability of the BTB than the LPS-treated mice, but these changes could be partially recovered by gut microbiota transplantation. In conclusion, these above results proved for the first time that gut microbiota is involved in the pathogenesis of orchitis, which laid a good foundation for the subsequent development of anti-orchitis drugs and probiotic targeting intestinal flora.

Bovine testicular heat stress: From climate change to effects on microRNA profile

Heat stress is caused by exposure of animals to high temperatures and humidity, outside their thermal comfort zone. This can have negative outcomes, including adversely affecting general well-being and reducing productive and reproductive performance. In males, heat stress can disrupt testicular thermoregulation, with deleterious effects on spermatogenesis and consequently, decreases in sperm quality and fertility potential. Thus, high environmental temperature is considered one of the most important factors that predisposes bulls to subfertility and has already been the subject of many studies, particularly in tropical or subtropical countries. It is essential to study effects of testicular heat stress in bulls, know the chronology of clinical and sperm findings, and understand the underlying pathophysiology. In addition, elucidating molecular mechanisms involved in heat stress and testicular function could provide the basis for effective, evidence-based strategies for selecting more thermotolerant animals. Excessive heat affects expression of messenger RNA (mRNA) and microRNA (miRNA) in sperm, which have important roles in regulating male fertility. Based on current trends in climate change, the incidence of chronically high temperatures that cause heat stress is expected to increase, posing increasing risks to health and survival of many species. The study of mRNAs and miRNAs can provide valuable insights to select animals that are more resilient to climate change. In addition to the search for more thermotolerant animals, other strategies to mitigate effects of heat stress include reproductive biotechniques and promotion of a better environment.

Revisiting cadmium-induced toxicity in the male reproductive system: an update

Heavy metals like cadmium (Cd) are one of the main environmental pollutants, with no biological role in the human body. Cd has been well-documented to have disastrous effects on both plants and animals. It is known to accumulate in kidneys, lungs, liver, and testes and is thought to affect these organs' function over time, which is linked to a very long biological half-life and a very poor rate of elimination. According to recent researches, the testes are extremely vulnerable to cadmium. The disruption of the blood-testis barrier, seminiferous tubules, Sertoli cells, and Leydig cells caused by cadmium leads to the loss of sperm through various mechanisms, such as oxidative stress, spermatogenic cell death, testicular swelling, dysfunction in androgen-producing cells, interference with gene regulation, disruption of ionic homeostasis, and damage to the vascular endothelium. Additionally, through epigenetic control, cadmium disrupts the function of germ cells and somatic cells, resulting in infertile or subfertile males. A full grasp of the mechanisms underlying testicular toxicity caused by Cd is very important to develop suitable strategies to ameliorate male fertility. Therefore, this review article outlines cadmium's impact on growth and functions of the testicles, reviews therapeutic approaches and protective mechanisms, considers recent research findings, and identifies future research directions.

The action of retinoic acid on spermatogonia in the testis

For mammalian spermatogenesis to proceed normally, it is essential that the population of testicular progenitor cells, A undifferentiated spermatogonia (Aundiff), undergoes differentiation during the A to A1 transition that occurs at the onset of spermatogenesis. The commitment of the Aundiff population to differentiation and leaving a quiescent, stem-like state gives rise to all the spermatozoa produced across the lifespan of an individual, and ultimately determines male fertility. The action of all-trans retinoic acid (atRA) on the Aundiff population is the determining factor that induces this change. Sertoli cells, omnipresent, nurse cells within the mammalian testis are responsible for synthesizing the atRA that prompts this change in the neonatal testicular environment. The mechanism of atRA synthesis and signaling has been robustly explored and, in this review, we have summarized what is currently known about the action of testicular atRA at the onset of spermatogenesis. We have combined this with evidence gained from prominent genetic studies that have further elucidated the function of genes critical to atRA synthesis. We have additionally described the effects of the first pulse of atRA delivered to the germ cells of the testis, which has been investigated using WIN 18,446 treatment which prevents atRA synthesis and induces spermatogenic synchrony. This method provides unparalleled resolution into cell and stage specific testicular changes, and combined with transgenic animal models, has allowed researchers to elucidate much regarding the onset of spermatogenesis.

Polyethylene Terephthalate Microplastic Exposure Induced Reproductive Toxicity Through Oxidative Stress and p38 Signaling Pathway Activation in Male Mice

Polyethylene terephthalate (PET) is a type of polymer plastic that is often used to make plastic bags, bottles, and clothes. However, the waste of such plastic products is decomposed into microplastics (MPs), which are plastic fragments smaller than 5 mm, by various external forces such as wind, UV radiation, mechanical wear, and biodegradation. PET MPs have been widely detected in the environment and human tissue samples; however, the toxicity and mechanism of PET MPs in mammals are still unclear. In this study, we investigated the male reproductive toxicity of PET MPs and their underlying mechanism. A total of 80 male mice were orally exposed to 0.01, 0.1, and 1 mg/d of PET MPs (with a diameter of 1 μm) for 42 days. The results showed that 1 μm PET MPs induced different degrees of pathological damage to testicular tissues, decreased sperm quality, and increased the apoptosis of spermatogenic cells via oxidative stress and p38 signaling pathway activation. To further illustrate and verify the mechanistic pathway, oxidative stress was antagonized using N-acetylcysteine (NAC), and the activation of the p38 signaling pathway was blocked using SB203580. The results revealed that the male reproductive injury effects after exposure to PET MPs were significantly ameliorated. Specifically, the testicular tissue lesions were relieved, the sperm quality improved, and the apoptosis of spermatogenic cells decreased. These results demonstrated that PET MP exposure induced male reproductive toxicity through oxidative stress and the p38 signaling pathway. This study provides new insights into the reproductive toxicity of MPs in males, as well as valuable references for public health protection strategies.

Temporal maturation of Sertoli cells during the establishment of the cycle of the seminiferous epithelium†

Sertoli cells, omnipresent, somatic cells within the seminiferous tubules of the mammalian testis are essential to male fertility. Sertoli cells maintain the integrity of the testicular microenvironment, regulate hormone synthesis, and of particular importance, synthesize the active derivative of vitamin A, all trans retinoic acid (atRA), which is required for germ cell differentiation and the commitment of male germ cells to meiosis. Stages VIII-IX, when atRA synthesis occurs in the testis, coincide with multiple germ cell development and testicular restructuring events that rely on Sertoli cell gene products to proceed normally. In this study, we have synchronized and captured the mouse testis at four recurrent points of atRA synthesis to observe transcriptomic changes within Sertoli cells as mice age and the Sertoli cells are exposed to increasingly developed germ cell subtypes. This work provides comprehensive, high-resolution characterization of the timing of induction of functional Sertoli cell genes across the first wave of spermatogenesis, and outlines in silico predictions of germ cell derived signaling mechanisms targeting Sertoli cells. We have found that Sertoli cells adapt to their environment, especially to the needs of the germ cell populations present and establish germ-Sertoli cell and Sertoli-Sertoli cell junctions early but gain many of their known immune-regulatory and protein secretory functions in preparation for spermiogenesis and spermiation. Additionally, we have found unique patterns of germ-Sertoli signaling present at each endogenous pulse of atRA, suggesting individual functions of the various germ cells in germ-Sertoli communication.

The potential influence and intervention measures of gut microbiota on sperm: it is time to focus on testis-gut microbiota axis

As the global male infertility rate continues to rise, there is an urgent imperative to investigate the underlying causes of sustained deterioration in sperm quality. The gut microbiota emerges as a pivotal factor in host health regulation, with mounting evidence highlighting its dual influence on semen. This review underscores the interplay between the Testis-Gut microbiota axis and its consequential effects on sperm. Potential mechanisms driving the dual impact of gut microbiota on sperm encompass immune modulation, inflammatory responses mediated by endotoxins, oxidative stress, antioxidant defenses, gut microbiota-derived metabolites, epigenetic modifications, regulatory sex hormone signaling. Interventions such as probiotics, prebiotics, synbiotics, fecal microbiota transplantation, and Traditional natural herbal extracts are hypothesized to rectify dysbiosis, offering avenues to modulate gut microbiota and enhance Spermatogenesis and motility. Future investigations should delve into elucidating the mechanisms and foundational principles governing the interaction between gut microbiota and sperm within the Testis-Gut microbiota Axis. Understanding and modulating the Testis-Gut microbiota Axis may yield novel therapeutic strategies to enhance male fertility and combat the global decline in sperm quality.

The safety of recombinant human hyaluronidase PH20 in nonclinical models: An overview of toxicology, pharmacology, and impact of anti-PH20 antibodies

Hyaluronan (HA) is a glycosaminoglycan that forms a gel-like barrier in the subcutaneous (SC) space, limiting bulk fluid flow and the dispersion of SC-administered therapeutics. Recombinant human hyaluronidase PH20 (rHuPH20) facilitates the rapid delivery of co-administered therapeutics by depolymerizing HA in the SC space. Administration of rHuPH20 can induce the formation of anti-rHuPH20 antibodies, or anti-drug antibodies (ADAs), with the potential to bind endogenous PH20 hyaluronidase in the adult testes and epididymis. Using a variety of relevant animal models and multiple dose regimens of rHuPH20 across the full spectrum of animal development, we demonstrated that rHuPH20 administration resulted in the formation of ADAs. Although these ADAs can bind both the recombinant rHuPH20 enzyme and recombinant versions of animal model-specific hyaluronidases, they had no impact on fertility parameters (as measured by sperm concentration and motility, litter size, and litter viability) or fetal development. We present the result of our nonclinical studies in order of the developmental lifecycle, beginning with adults. Toxicology studies that extend beyond the standard package are also presented. These studies demonstrate the favorable safety profile of rHuPH20 and ADAs in nonclinical models. Additionally, we identified substantial safety margins for clinically relevant doses of rHuPH20.

Screening of cytokine expression in human seminal plasma in associations with sperm disorders and markers of oxidative-antioxidant balance

Among the many factors with a proven relation to semen quality and male fertility, the determination of seminal plasma cytokines provides a promising direction for research into the identification of factors connected with male infertility. The interleukins: IL-1α, -1β, -2, -4, -6, -8, -10, -12p40, -12p70, -18, IFNγ, and GM-CSF, total oxidant (TOS) and antioxidant (TAS) status, were simultaneously examined in seminal plasmas and blood sera in terato- (n = 32), asthenoterato- (n = 33), and oligoasthenoteratozoospermic (n = 29) infertile men and in normozoospermic fertile men (n = 20). Our research shows different cytokine composition of the sera and seminal plasmas in all studied groups, along with much higher concentrations of seminal plasma GM-CSF, IFNγ, IL-1α, IL-4, IL-6, and IL-8 and lower IL-18 and TOS in the comparison to their sera levels. The seminal plasma concentrations of GM-CSF, IFNγ, IL-1α, -4, and -6 differ significantly between fertile and infertile as well as between teratozoospermic, asthenoteratozoospermic, and oligoasthenoteratozoospermic groups. The indication of the cause of different concentrations of cytokines in seminal plasmas of infertile men, and their associations with semen parameters and oxidative status, may be a promising direction for the search for new therapeutic targets that would directly affect the cells and tissues of male reproductive organs.

The Protective Role of L-Cysteine in the Regulation of Blood-Testis Barrier Functions-A Brief Review

Blood-testis barrier (BTB) genes are crucial for the cellular mechanisms of spermatogenesis as they protect against detrimental cytotoxic agents, chemicals, and pathogens, thereby maintaining a sterile environment necessary for sperm development. BTB proteins predominantly consist of extensive tight and gap junctions formed between Sertoli cells. These junctions form a crucial immunological barrier restricting the intercellular movement of substances and molecules within the adluminal compartment. Epithelial tight junctions are complex membrane structures composed of various integral membrane proteins, including claudins, zonula occludens-1, and occludin. Inter-testicular cell junction proteins undergo a constant process of degradation and renewal. In addition, the downregulation of genes crucial to the development and preservation of cell junctions could disrupt the functionality of the BTB, potentially leading to male infertility. Oxidative stress and inflammation may contribute to disrupted spermatogenesis, resulting in male infertility. L-cysteine is a precursor to glutathione, a crucial antioxidant that helps mitigate damage and inflammation resulting from oxidative stress. Preclinical research indicates that L-cysteine may offer protective benefits against testicular injury and promote the expression of BTB genes. This review emphasizes various BTB genes essential for preserving its structural integrity and facilitating spermatogenesis and male fertility. Furthermore, it consolidates various research findings suggesting that L-cysteine may promote the expression of BTB-associated genes, thereby aiding in the maintenance of testicular functions.

An in vitro testicular organoid model for the study of testis morphogenesis, somatic cell maturation, endocrine function, and toxicological assessment of endocrine disruptors

Male reproductive capacity has fallen considerably in recent decades; in addition, the incidence of testicular cancer has increased in many developed countries. The cause of this phenomenon is unknown, but environmental toxicants are considered a major contributing factor. To study potential reproductive toxicants, robust in vitro testis models are needed. We have recently established a porcine testis organoid system with a high resemblance to the architectures of innate testis tissue. Here, we further investigated the testis morphogenesis, cell maturation, and endocrine function of the testis organoids. We also challenged this system with abiraterone, a steroidogenic inhibitor, to validate its suitability as an in vitro platform for endocrine toxicology tests. Our results showed that the testis cells in the organoids reorganize into testis cordal structures, and the cordal relative areas increase in the organoids over time of culture. Moreover, the diameters and cell numbers per cross-section of the cordal structures increased over time. Interestingly, Sertoli cells in the organoids gradually underwent maturational changes by showing increased expression of androgen receptors, decreased expression of the anti-müllerian hormone, and formation of the blood-testis barrier. Next, we confirmed that the organoids respond to hormonal stimulation and release multiple sex hormones, including testosterone, estradiol, and progesterone. Finally, we showed that the production of testosterone and estradiol in this system can be inhibited in response to the steroidogenic inhibitor. Taken together, our organoid system provides a promising in vitro platform for male reproductive toxicology studies on testis morphogenesis, somatic cell maturation, and endocrine production.

From Germ Cells to Implantation: The Role of Extracellular Vesicles

Extracellular vesicles represent a large heterogeneous class of near and long-distance intercellular communication mediators, released by both prokaryotic and eukaryotic cells. Specifically, the scientific community has shown growing interest in exosomes, which are nano-sized vesicles with an endosomal origin. Not so long ago, the physiological goal of exosome generation was largely unknown and required more investigation; at first, it was hypothesized that exosomes are able to remove excess, reject and unnecessary constituents from cells to preserve cellular homeostasis. However, thanks to recent studies, the central role of exosomes in regulating cellular communication has emerged. Exosomes act as vectors in cell-cell signaling by their cargo, proteins, lipids, and nucleic acids, and influence physiological and pathological processes. The findings on exosomes are widespread in a large spectrum of biomedical applications from diagnosis and prognosis to therapies. In this review, we describe exosome biogenesis and the current methods for their isolation and characterization, emphasizing the role of their cargo in female reproductive processes, from gametogenesis to implantation, and the potential involvement in human female disorders.

The Protective Effect of Quercetin against the Cytotoxicity Induced by Fumonisin B1 in Sertoli Cells

Fumonisin B1 (FB1), a mycotoxin produced by Fusarium species, is prevalent in crops and animal feed, posing significant health risks to livestock and humans. FB1 induces oxidative stress in Sertoli cells, destroys testicular structure, and affects spermatogenesis. However, methods to mitigate the reproductive toxicity of FB1 in testes remain unknown. Quercetin, a natural flavonoid antioxidant, may offer protective benefits. This study investigated the protective effects and mechanisms of quercetin against FB1-induced reproductive toxicity in TM4 cells (a Sertoli cell line). The results indicated that 40 μM quercetin improved cell viability, reduced apoptosis, and preserved cell functions. Quercetin also decreased reactive oxygen species (ROS) levels in TM4 cells exposed to FB1, enhanced the expression of antioxidant genes, and improved mitochondrial membrane potential. Compared with FB1 alone, the combination of quercetin and FB1 increased ATP levels, as well as pyruvate and lactic acid, the key glycolysis products. Furthermore, this combination elevated the mRNA and protein expression of glycolysis-related genes, including glucose-6-phosphate isomerase 1 (Gpi1), hexokinase 2 (Hk2), aldolase (Aldoa), pyruvate kinase, muscle (Pkm), lactate dehydrogenase A (Ldha) and phosphofructokinase, liver, B-type (Pfkl). Quercetin also boosted the activity of PKM and LDHA, two crucial glycolytic enzymes. In summary, quercetin mitigates FB1-induced toxicity in TM4 cells by reducing ROS levels and enhancing glycolysis. This study offers new insights into preventing and treating FB1-induced toxic damage to the male reproductive system and highlights the potential application of quercetin.