Light pollution: time to consider testicular effects.

Technological advances have led to a modern-day lighting and smartphone revolution, with artificial light exposure at night increasing to levels never before seen in the evolutionary history of living systems on Earth. Light as a pollutant, however, remains largely unrecognized, and the reproductive effects of light pollution are mostly if not entirely unconsidered. This is despite the reproductive system being intricately linked to metabolism and the circadian system, both of which can be disturbed even by low levels of light. Here, we aim to change this perspective by reviewing the physiological and pathophysiological mechanisms by which light exposure alters the intricate hormonal, metabolic and reproductive networks that are relevant to reproductive toxicology. Nascent human studies have recently identified the photoreceptors responsible for the light dose relationship with melatonin suppression and circadian re-entrainment, directly shown the association between the alignment of light-dark cycles with activity-rest cycles on metabolic health and provided proof-of-principle that properly timed blue light-enriched and blue light-depleted delivery can accelerate circadian re-entrainment. With these advances, there is now a need to consider testicular effects of light pollution.

Expression of GLOD4 in the Testis of the Qianbei Ma Goat and Its Effect on Leydig Cells.

The expression pattern of GLOD4 in the testis and its regulatory effect on testicular cells was explored in goats to enhance our understanding of spermatogenesis and improve reproduction in breeding rams. In this study, we demonstrated the localization of GLOD4 in testicular cells using immunohistochemistry and subcellular localization analyses. Subsequently, we analyzed the GLOD4 expression pattern in four age-based groups (0, 6, 12, and 18 months old) using real-time quantitative polymerase chain reaction (qRT-PCR) and protein blotting. Finally, we performed GLOD4 silencing and overexpression studies in Leydig cells (LCs) and explored the effects on cell proliferation, the cell cycle, steroid hormone secretion and the expression of candidate testosterone hormone-regulated genes. GLOD4 was mainly expressed in Leydig cells, and the subcellular localization results showed that the GLOD4 protein was mainly localized in the cytoplasm and nucleus. Silencing of GLOD4 significantly suppressed the mRNA expression levels of the testosterone secretion-related genes CYP11A1, 3ß-HSD, and CYP17A1 and the mRNA expression levels of cell cycle-related genes CDK6, PCNA, and Cyclin E. Moreover, the cell cycle was blocked at the G2/M phase after GLOD4 silencing, which significantly suppressed testosterone secretion. In contrast, GLOD4 overexpression significantly increased the mRNA expression levels of the testosterone secretion-related genes CYP11A1, 3ß-HSD, and CYP17A1 and increased the expression of the cell cycle-related genes CDK6, PCNA, and Cyclin E. Moreover, GLOD4 overexpression promoted the cell cycle from G0/G1 phases to enter the S phase and G2/M phases, promoted the secretion of testosterone. Taken together, our experimental results indicate that GLOD4 may affect the development of cells in Qianbei Ma goats of different ages by influencing the cell cycle, cell proliferation, and testosterone hormone synthesis. These findings enhance our understanding of the functions of GLOD4 in goats.

An Ovarian Sertoli-Leydig Cell Tumor with Elevated Alpha-Fetoprotein in an Adolescent: A Rare Case Report and Literature Review.

An ovarian Sertoli-Leydig cell tumor is a rare type of sex cord-stromal tumor of the ovary. Typically, it presents as abdominal pain or androgenic manifestations in women in the second to third decade of life. While cases of ovarian Sertoli-Leydig cell tumor associated with increased levels of alpha-fetoprotein are rare, they are reported to be the most common alpha-fetoprotein-producing ovarian non-germ cell tumor. We report the case of a 16-year-old patient, who presented with complaints of amenorrhea that had lasted for one year. Transabdominal ultrasound revealed the presence of a tumor in the right ovary, measuring 9.3 × 5.8 cm in size. The laboratory investigation showed an increased level of alpha-fetoprotein. The patient underwent laparoscopic right salpingo-oophorectomy. Histopathological examination confirmed the presence of a moderately differentiated (G2) Sertoli-Leydig cell tumor in the right ovary. For reproductive-age patients with disease confined to the ovary, fertility-sparing surgery is recommended. According to the current recommendations, the administration of adjuvant chemotherapy is indicated in cases of the presence of heterologous elements, poorly differentiated tumors, or FIGO stages IB-IV. As there were no high-risk factors and no residual disease in this case, there were no indications for further treatment with adjuvant chemotherapy. A recent follow-up visit showed that the patient is in complete remission. This report presents a detailed description of the findings, differential diagnosis, clinical course, chosen treatment, and prognosis. Also, a comprehensive literature review of ovarian Sertoli-Leydig cell tumors, focusing on their clinical presentation, laboratory findings, macroscopic and histopathological features, genetics, clinical management, prognostic factors and follow-up, is provided.

Hypoxia impairs male reproductive functions via inducing rat Leydig cell ferroptosis under simulated environment at altitude of 5000 m.

AIMS: Many studies demonstrated reproductive damage in men residing in plains who are exposed to hypoxia at high altitudes. However, little is known about mechanisms between male reproductive impairment and hypobaric hypoxia. Hypoxia is one of the reasons for the imbalance of cellular redox system. Ferroptosis, involved in many pathophysiological progresses, is an oxidative damage-related, iron-dependent regulated cell death, which needs exogenous inducer. In our study, we explored the mechanism between hypoxia and male reproductive dysfunction. MATERIALS AND METHODS: Here, we established animal model simulating hypobaric hypoxia at an altitude of 5000 m and used ELISA, WB, qPCR, flow cytometry and etc. to obtain different results. KEY FINDINGS: The results demonstrated decrease of plasma testosterone (T) and free testosterone (FT) levels under hypoxia, meanwhile there's decline in sperm counts and sperm motility, coupled with increase in sperm malformation rates. Flow cytometry confirmed significant reduction in Leydig cell numbers. Prussian blue staining showed iron depositions in interstitial testis. Features of ferroptosis such as increased MDA (malondialdehyde) levels, reduced solute carrier family 7 member 11 (SLC7A11, xCT) and glutathione peroxidase 4 (GPX4) expression were observed in testis after hypoxic exposure. Further in vitro experiments, we observed that hypoxia suppressed xCT-GPX4 pathway and enhanced cellular ROS accumulation to lead Leydig cell proliferation activity decline. SIGNIFICANCE: Our findings firstly indicated that hypoxia leads to male reproductive dysfunction via inducing Leydig cell ferroptosis. This discovery may offer a potential intervention target for addressing male reproductive injuries under hypoxic conditions.

p38MAPK/HSPB1 is involved in the regulatory effects of selenomethionine on the apoptosis, viability and testosterone secretion of sheep Leydig cells exposed to heat.

Testosterone derived from testicular Leydig cells (LCs) is important for male sheep, and the testis is susceptible to external temperature. The present study aimed to explore the alleviating effect of selenomethionine (Se-Met) on heat-induced injury in Hu sheep LCs. Isolated LCs were exposed to heat (41.5°C, heat exposure, HE) or not (37°C, nonheat exposure, NE), and cells in NE and HE were treated with 0 (C) or 8 µmol/L (S) Se-Met for 6 h. Cell viability, testosterone level, and the expression of GPX1, HSD3B, apoptosis-related genes and p38 mitogen-activated protein kinase (p38MAPK)/heat shock protein beta-1 (HSPB1) pathway were examined. The results showed that Se-Met increased GPX1 expression (NE-S vs. NE-C: 2.28-fold; HE-S vs. HE-C: 2.36-fold, p < 0.05) and alleviated heat-induced decrease in cell viability (HE-S vs. HE-C: 1.41-fold; HE-C vs. NE-C: 0.61-fold, p < 0.01), although the viability was still lower than that in the NE-C cells (HE-S vs. NE-C: 0.85-fold) and Se-Met-treated cells (HE-S vs. NE-S: 0.81-fold). Se-Met relieved heat-induced decrease in testosterone level (HE-S vs. HE-C: 1.84-fold, p < 0.05) and HSD3B expression (HE-S vs. HE-C: 1.67-fold, p < 0.05). Se-Met alleviated heat-induced increase in Bcl2-associated protein X (BAX) expression (HE-C vs. HE-S: 2.4-fold, p < 0.05), and decrease in B-cell lymphoma-2 (BCL2) expression (HE-S vs. HE-C: 2.62-fold, p < 0.05), resulting in increased BCL2/BAX ratio in the HE-S cells (HE-S vs. HE-C: 5.24-fold, p < 0.05). Furthermore, Se-Met alleviated heat-induced activation of p-p38MAPK/p38MAPK (HE-C vs. HE-S: 1.79-fold, p < 0.05) and p-HSPB1/HSPB1 (HE-C vs. HE-S: 2.72-fold, p < 0.05). In conclusion, p38MAPK/HSPB1 might be involved in Se-Met-mediated alleviation of heat-induced cell apoptosis, cell viability and testosterone secretion impairments in sheep LCs.

Chronic Polystyrene Microplastic Exposure Reduces Testosterone Levels in Mice through Mitochondrial Oxidative Stress and BAX/BCL2-Mediated Apoptosis.

Microplastics (MPs) have emerged as a major environmental issue. They have been found to cause significant reproductive toxicity and lower testosterone levels in adult males, though the exact mechanisms remain unclear. In this study, C57bl/6 mice were orally exposed to saline or varying doses (0.25, 0.5, and 1 mg/day) of 5 µm polystyrene MPs (PS-MPs) for 4 weeks, and TM3 mouse Leydig cells were treated with different concentrations of PS-MPs. Our results found that exposure to PS-MPs significantly reduced testosterone levels and impaired the synthesis function of testicular steroids. In vitro, PS-MPs reduced steroid synthesis in Leydig cells. Treatment with PS-MPs significantly increased the apoptosis rate and BAX/BCL2 ratio in Leydig cells. Additionally, GSH-px and SOD activities decreased, while MDA levels increased, along with a rise in mitochondrial ROS. In conclusion, chronic PS-MP exposure reduced testosterone levels in mice through mitochondrial oxidative stress and BAX/BCL2-mediated apoptosis. This study offers new insights into the health risks posed by MPs.

LHCGR inactivating variants: single center experience and systematic review of phenotype-genotype of 46,XY and 46,XX patients.

Background: The data on Leydig cell hypoplasia (LCH) resulting from biallelic Luteinizing hormone/chorionic gonadotropin receptor (LHCGR) inactivating variants is limited to case series. Methods: We aim to describe our patients and perform systematic review of the patients with LHCGR inactivating variants in the literature. Detailed phenotype and genotype data of three patients from our centre and 85 (46,XY: 67; 46,XX: 18) patients from 59 families with LHCGR-inactivating variants from literature were described. Results: Three 46,XY patients (age 6-18 years) from our center, with two reared as females, had two novel variants in LHCGR. Systematic review (including our patients) revealed 72 variants in 88 patients. 46,XY patients (n = 70, 56 raised as females) presented with pubertal delay (n = 41) or atypical genitalia (n = 17). Sinnecker score ≥3 (suggesting antenatal human chorionic gonadotropin (hCG) inaction) was seen in 80% (56/70), and hCG-stimulated testosterone was low (<1.1 ng/mL) in 77.4% (24/31), whereas puberty/postpubertal age, high luteinizing hormone (LH) (97.6%, 41/42) and low (<1.0 ng/mL) basal testosterone (94.9%, 37/39) was observed in most. Follicle stimulating hormone was elevated in 21/51 of these patients. Variants with <10% receptor function were exclusively seen in cohorts with Sinnecker 4/5 (10/15 vs 0/5, P = 0.033). 46,XX patients (n = 18) presented with oligo/amenorrhea and/or anovulatory infertility and had polycystic ovaries (7/9) with median LH of 10 IU/L (1.2-38). Conclusion: In summary, this study comprehensively characterizes LHCGR variants, revealing genotype-phenotype correlations and informing clinical management of LCH. In 46,XY LCH patients, pubertal LH inaction is uniform with variable severity of antenatal hCG inaction. Few mutant LHCGR have differential actions for LH and hCG.

Single-cell transcriptomic analysis reveals that the APP-CD74 axis promotes immunosuppression and progression of testicular tumors.

Testicular tumors represent the most common malignancy among young men. Nevertheless, the pathogenesis and molecular underpinning of testicular tumors remain largely elusive. We aimed to delineate the intricate intra-tumoral heterogeneity and the network of intercellular communication within the tumor microenvironment. A total of 40,760 single-cell transcriptomes were analyzed, encompassing samples from six individuals with seminomas, two patients with mixed germ cell tumors, one patient with a Leydig cell tumor, and three healthy donors. Five distinct malignant subclusters were identified in the constructed landscape. Among them, malignant 1 and 3 subclusters were associated with a more immunosuppressive state and displayed worse disease-free survival. Further analysis identified that APP-CD74 interactions were significantly strengthened between malignant 1 and 3 subclusters and 14 types of immune subpopulations. In addition, we established an aberrant spermatogenesis trajectory and delineated the global gene alterations of somatic cells in seminoma testes. Sertoli cells were identified as the somatic cell type that differed the most from healthy donors to seminoma testes. Cellular communication between spermatogonial stem cells and Sertoli cells is disturbed in seminoma testes. Our study delineates the intra-tumoral heterogeneity and the tumor immune microenvironment in testicular tumors, offering novel insights for targeted therapy. © 2024 The Author(s). The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Ovarian Sertoli-Leydig Cell Tumors in a Three-Year-Old Child.

Ovarian Sertoli-Leydig cell tumors (SLCT) are extremely rare malignant tumors deriving from the sex cord stroma. An abdominal mass and a virilization syndrome dominate the clinical symptoms. This particular tumor poses diagnostic and therapeutic problems. Prognosis depends on staging (the International Federation of Gynecology and Obstetrics (FIGO)/tumor, node, metastasis (TNM)) and differentiation. The treatment is surgical, combined with adjuvant chemotherapy in certain cases. We report the case of a three-year-old girl admitted to our department for signs of virilization with an abdominal mass. The literature does not contain any reports of a younger case. Ovarian SLCTs should be considered in every girl presenting with signs of virilization and a lower abdominal mass. The prognosis and management depend on the results of the histological analysis and extension evaluation in order to define therapeutic management.

FOXO4-DRI improves spermatogenesis in aged mice through reducing senescence-associated secretory phenotype secretion from Leydig cells.

Male ageing is always accompanied by decreased fertility. The forkhead O (FOXO) transcription factor FOXO4 is reported to be highly expressed in senescent cells. Upon activation, it binds p53 in the nucleus, preventing senescent cell apoptosis and maintaining senescent cells in situ. Leydig cells play key roles in assisting spermatogenesis. Leydig cell senescence leads to deterioration of the microenvironment of the testes and impairs spermatogenesis. In this study, we observed that FOXO4-DRI, a specific FOXO4- p53 binding blocker, induced apoptosis in senescent Leydig cells, reduced the secretion of certain Senescence-Associated Secretory Phenotype and improved the proliferation of cocultured GC-1 SPG cells. In naturally aged mice, FOXO4-DRI-treated aged mice exhibited increased sperm quality and improved spermatogenesis.

When Diagnosis Takes a Turn: A Case Series on Testicular Adrenal Rest Tumor/Leydig Cell Tumor.

Testicular adrenal rest tumor (TART) is a known complication of congenital adrenal hyperplasia (CAH) that simulates testicular germ cell tumors to the extent that they can pose a diagnostic challenge to treating physicians. In this case series, we have presented four patients with different clinical scenarios but all of them presented with a common symptom of bilateral testicular masses. Their clinical histories were strongly suggestive of CAH. Most of them were treated initially as cases of germ cell tumor (Leydig) as their clinical features were overlapping, posing a diagnostic challenge. The histopathological features of CAH and Leydig cell tumors overlap considerably. Diagnosis of CAH must always be kept in mind as a differential diagnosis in patients presenting with bilateral testicular swellings. Timely diagnosis of TARTs and CAH can help preserve testicular functions. Careful histopathological analysis can add to the clinical features of CAH and Leydig tumors to correctly diagnose these patients. Here, we discuss this diagnostic challenge in our four patients.

Zinc Supplementation Reduces ROS Production and Prevents MDMA-Induced Apoptosis in TM3 Leydig Cells via the Inhibition of Pro-Apoptotic Proteins.

MDMA can cause serious adverse effects on vital organs such as the heart, brain, and liver. Additionally, MDMA consumption can also potentially cause various endocrine system dysfunctions. The previous study has shown that pre-treatment of zinc can reduce the cytotoxicity of MDMA on the Leydig cell line (TM3). In this study, we investigated the mechanisms involved in the treatment with MDMA on the apoptosis of TM3 cells and the effects of zinc pre-treatment on reducing the apoptotic effects of MDMA. TM3 cells were incubated with MDMA (5 mM), zinc (8 µM), and zinc (8 µM) prior to MDMA (5 mM) for 48 h. The cells were pre-treated with zinc for 24 h prior to the administration of MDMA, and the total culture time was 48h. The effect of different treatment groups in causing oxidative stress and apoptosis in TM3 cells was measured by DCF, TUNNEL, and western blot tests, respectively. Our results revealed that the number of DCF and tunnel-positive cells increases as a result of MDMA treatment. In addition, the treatment with MDMA increased the expression of pro-apoptotic proteins caspase 3, Bax, and p53. Conversely, the expression of anti-apoptotic protein Bcl-2 decreased. Zinc pre-treatment significantly decreased the expression of pro-apoptotic proteins and the number of tunnels and DCF-positive cells compared to the MDMA-only group. It is concluded that MDMA has a toxic effect and causes apoptosis on TM3 cells, and also, pre-treatment with zinc mitigates the ROS production and toxic effect of MDMA and MDMA-induced apoptosis in TM3 cells.

Triclosan inhibits testosterone biosynthesis in adult rats via inducing m6A methylation-mediated autophagy.

Triclosan is a potent antibacterial compound widely used in everyday products. Whether triclosan affects Leydig cell function in adult male rats remains unknown. In this study, 0, 50, 100, or 200 mg/kg/day triclosan was gavaged to Sprague-Dawley male rats from 56 to 63 days postpartum. Triclosan significantly reduced serum testosterone levels at ≥ 50 mg/kg/day via downregulating the expression of Leydig cell gene Lhcgr, Scarb1, Star, Cyp11a1, Hsd3b1, Cyp17a1, and Hsd17b3 and regulatory transcription factor Nr3c2 at 100-200 mg/kg. Further analysis showed that triclosan markedly increased autophagy as shown by increasing LC3II and BECN1 and decreasing SQSTM1. The mRNA m6A modification analysis revealed that triclosan significantly downregulated Fto expression at 200 mg/kg while upregulating Ythdf1 expression at 100 and 200 mg/kg, leading to methylation of Becn1 mRNA as shown by MeRIP assay. Triclosan significantly inhibited testosterone output in rat R2C Leydig cells at ≥ 5 µM via downregulating Fto and upregulating Ythdf1. SiRNA Ythdf1 knockdown can reverse triclosan-mediated mitophagy in R2C cells, thereby reversing the reduction of testosterone output. In summary, triclosan caused Becn1 m6A methylation by downregulating Fto and upregulating Ythdf1, which accelerated Becn1 translation, thus leading to the occurrence of autophagy and the decrease of testosterone biosynthesis.

Single-cell insights into mouse testicular toxicity under peripubertal exposure to di(2-ethylhexyl) phthalate.

Male fertility depends on normal pubertal development. Di-(2-ethylhexyl) phthalate (DEHP) is a potent antiandrogen chemical, and exposure to DEHP during peripuberty can damage the developing male reproductive system, especially the testis. However, the specific cellular targets and differentiation processes affected by DEHP, which lead to testicular toxicity, remain poorly defined. Herein, we presented the first single-cell transcriptomic profile of the pubertal mouse testis following DEHP exposure. To carry out the experiment, 2 groups (n = 8 each) of 3-week-old male mice were orally administered 0.5% carboxymethylcellulose sodium salt or 100 mg/kg body weight DEHP daily from postnatal day 21-48, respectively. Using single-cell RNA sequencing, a total of 31 distinct cell populations were identified, notably, Sertoli and Leydig cells emerged as important targets of DEHP. DEHP exposure significantly decreased the proportions of Sertoli cell clusters expressing mature Sertoli markers (Sox9 and Ar), and selectively reduced the expression of testosterone synthesis genes in fetal Leydig cells. Through cell-cell interaction analyses, we observed changed numbers of interactions in Sertoli cells 1 (SCs1), Leydig cells 1 (LCs1), and interstitial macrophages, and we also identified cell-specific ligand gene expressions in these clusters, such as Inha, Fyn, Vcam1, and Apoe. Complementary in vitro assays confirmed that DEHP directly reduced the expression of genes related to Sertoli cell adhesion and intercellular communication. In conclusion, peripubertal DEHP exposure reduced the number of mature Sertoli cells and may disrupt testicular steroidogenesis by affecting the testosterone synthesis genes in fetal Leydig cells rather than adult Leydig cells.

Gonadal efficacy of Thymus quinquecostatus Celakovski: Regulation of testosterone levels in aging mouse models.

Late-onset hypogonadism (LOH) is an age-related disease in men characterized by decreased testosterone levels with symptoms such as decreased libido, erectile dysfunction, and depression. Thymus quinquecostatus Celakovski (TQC) is a plant used as a volatile oil in traditional medicine, and its bioactive compounds have anti-inflammatory potential. Based on this knowledge, the present study aimed to investigate the effects of TQC extract (TE) on LOH in TM3 Leydig cells and in an in vivo aging mouse model. The aqueous extract of T. quinquecostatus Celakovski (12.5, 25, and 50 µg/mL concentrations) was used to measure parameters such as cell viability, testosterone level, body weight, and gene expression, via in vivo studies. Interestingly, TE increased testosterone levels in TM3 cells in a dose-dependent manner without affecting cell viability. Furthermore, TE significantly increased the expression of genes involved in the cytochrome P450 family (Cyp11a1, Cyp17a1, Cyp19a1, and Srd5a2), which regulate testosterone biosynthesis. In aging mouse models, TE increased testosterone levels without affecting body weight and testicular tissue weight tissue of an aging animal group. In addition, the high-dose TE-treated group (50 mg/kg) showed significantly increased expression of the cytochrome p450 enzymes, similar to the in vitro results. Furthermore, HPLC-MS analysis confirmed the presence of caffeic acid and rosmarinic acid as bioactive compounds in TE. Thus, the results obtained in the present study confirmed that TQC and its bioactive compounds can be used for LOH treatment to enhance testosterone production.

Human benign Leydig cell tumor - Biochemical evaluation.

Recently we reported expressional alterations in 219 genes and their transcripts in Leydig cell tumors but nowadays there is still a lack of full basic biochemical characteristics of these tumors. The discovery of potential biochemical markers for tumor management from early detection, treatments, and control of therapy results may markedly supplement genetic data. Leydig cell micronodules were obtained from patients with azoospermia who were qualified for testicular biopsy. The biochemistry of Leydig cell tumors was analyzed using histological staining and spectrophotometric measurements of total proteins, carbohydrates, lipids, and nucleic acids. In addition, the levels of calcium (Ca2 +), copper (Cu2 +), zinc (Zn2 +), and selenium (Se2 +) ions were measured. When compared to healthy testis we revealed, for the first time, that in the interstitial tissue with Leydig cell tumors, great amounts of proteins, carbohydrates, lipids, and acids were dislocated from the seminiferous tubules. Measurements of organic compounds showed a decrease (P < 0.05) only in the Cu2 + content in Leydig cell tumors which may be related to their altered biochemical structure. This specific result may be promising for designing further approaches to manage this tumor based on combining morphological and molecular data.

A Sertoli-Leydig ovarian tumor presenting as ovarian torsion: A case report.

Torsion occurs as a complication in 10% of cases of ovarian tumors. It predominantly occurs in benign ones, while malignant tumors are less prone to torsion. Sertoli-Leydig cell tumors are highly unusual sex cord-stromal tumors of the ovary, accounting for less than 0.2% of all ovarian cancers. A 39-year-old patient presented to the emergency department with a Sertoli-Leydig cell tumor diagnosed due to ovarian torsion. The clinical presentation was characterized by abdominal pain. Ultrasound indicated signs of torsion, and torsion of the right ovary was subsequently confirmed during laparotomy. A salpingo-oophorectomy was performed, and histological examination revealed a moderately differentiated Sertoli-Leydig cell tumor. Sertoli-Leydig cell tumors often present with hormone-related or non-hormonal symptoms. Surgery plays a crucial role in both diagnosis and treatment. Postoperative treatment is not necessary for well-differentiated Sertoli-Leydig cell tumors in stage IA-IB. However, patients with grade 2-3 disease, advanced stage, or heterologous elements may consider adjuvant treatment. As these tumors are rare, this case contributes to the documentation of Sertoli-Leydig cell tumors, with a case diagnosed due to ovarian torsion. The case highlights the importance of establishing international registries of Sertoli-Leydig cell tumor cases for standardized management.

Loss of PBX1 function in Leydig cells causes testicular dysgenesis and male sterility.

Leydig cells are essential components of testicular interstitial tissue and serve as a primary source of androgen in males. A functional deficiency in Leydig cells often causes severe reproductive disorders; however, the transcriptional programs underlying the fate decisions and steroidogenesis of these cells have not been fully defined. In this study, we report that the homeodomain transcription factor PBX1 is a master regulator of Leydig cell differentiation and testosterone production in mice. PBX1 was highly expressed in Leydig cells and peritubular myoid cells in the adult testis. Conditional deletion of Pbx1 in Leydig cells caused spermatogenic defects and complete sterility. Histological examinations revealed that Pbx1 deletion impaired testicular structure and led to disorganization of the seminiferous tubules. Single-cell RNA-seq analysis revealed that loss of Pbx1 function affected the fate decisions of progenitor Leydig cells and altered the transcription of genes associated with testosterone synthesis in the adult testis. Pbx1 directly regulates the transcription of genes that play important roles in steroidogenesis (Prlr, Nr2f2 and Nedd4). Further analysis demonstrated that deletion of Pbx1 leads to a significant decrease in testosterone levels, accompanied by increases in pregnenolone, androstenedione and luteinizing hormone. Collectively, our data revealed that PBX1 is indispensable for maintaining Leydig cell function. These findings provide insights into testicular dysgenesis and the regulation of hormone secretion in Leydig cells.