Sox9 protein in rat sertoli cells is age and stage dependent

Hyaluronic acid-alginate hydrogel stimulates the differentiation of neonatal mouse testicular cells into hepatocyte-like and other cell lineages in three-dimensional culture

BACKGROUND INFORMATION

Extracellular matrix (ECM)-derived hydrogels are frequently used in three-dimensional (3D) cell culture and organoid formation in several tissues. However, in the 3D cultivation of testicular cells, the hyaluronic acid (HA) hydrogel has not received as much attention. This study examined the effects of three distinct composites, including HA-alginate (HA-Alg), HA-alginate-collagen (HA-Alg-Col), and HA-alginate-decellularized ECM (HA-Alg-dECM), on mouse testicular cell culture and in vitro spermatogenesis.

METHODS

For the creation of composites, the concentration of biomaterials used was 0.5% HA, 1% alginate, 2.5 mg/mL collagen, and 25 mg/mL dECM derived from the testicles of Rams. After 3D culture of 5 days post-partum (dpp) mouse testicular cells for 14 days, HA-Alg was selected as a superior composite due to the greater number and size of the produced organoids. Then, cell culture was rerun by HA-Alg for 14 days, which was later extended for an additional 28 days. In addition, the 3D culture of 10 dpp mouse testicular cells was used to compare with 5 dpp mice on day 14. The morphology and gene expression were analyzed using appropriate techniques.

RESULTS

On day 14, the HA-Alg hydrogel showed significantly more organoids in terms of size and number than the other two groups (p < 0.05); nevertheless, none of the groups showed the expected signs of testis organoids. Remarkably, on day 14, the histology and immunostaining tests revealed features of hepatocyte-like cells (HLCs) and albumin production as a marker of HLC functionality. Furthermore, the analysis of gene expression verified the significant expression of angiogenesis markers (p < 0.01). After the extended culture to 28 days, 5 dpp testicular cells once more differentiated into erythrocytes and HLCs, while a small number of organoids showed the characteristic of renal cells. Cell culture of 10 dpp mice for 14 days showed a wide range of cell lineages, including renal, glandular, chondrocyte, and hepatocyte-like cells in comparison to the 5 dpp mice.

CONCLUSION AND SIGNIFICANCE

While the HA-Alg composite did not support spermatogenesis in the 3D culture of mouse testicular cells, it demonstrated an unpredicted potential for promoting the differentiation of neonate mouse testicular cells into HLC, erythrocytes, and other cell lineages.

Prior exposure to alkylating agents negatively impacts testicular organoid formation in cells obtained from childhood cancer patients

STUDY QUESTION

Can human pre- and peri-pubertal testicular cells obtained from childhood cancer patients, previously treated with chemotherapy, form testicular organoids (TOs)?

SUMMARY ANSWER

Organoid formation from testicular tissue collected from childhood cancer patients positively correlates with SRY-Box transcription factor 9 (SOX9) expression in Sertoli cells, which in turn negatively correlates with previous exposure to alkylating chemotherapy.

WHAT IS KNOWN ALREADY

Pre- and peri-pubertal boys exposed to highly gonadotoxic therapies can only safeguard their fertility potential through testicular tissue cryopreservation. Today, there is no established clinical tool to restore fertility using these testicular samples. Organoids hold promise in providing fundamental early insights in creating such platforms. However, the generation of TOs that closely resemble the innate testis, to enable a thorough monitoring of the necessary steps for germ cell differentiation and somatic functionalities, remains a challenge.

STUDY DESIGN SIZE DURATION

We used a Matrigel-based three-layer gradient culture system to generate human TOs and to reveal whether chemotherapy exposure affects TO formation capacity and the functionality of pre- and peri-pubertal testicular somatic cells. Testicular cells of 11 boys (aged 7.7 ± 4.1 (mean ± SD) years) were assessed for TO formation in relation to previous chemotherapy exposure and SOX9 expression in histological sections of paraffin-embedded testicular tissue samples collected on the day of biopsy and compared with testicular tissue samples obtained from 28 consecutive patients (aged 6.9 ± 3.8 (mean ± SD) years). All 39 patients were part of the fertility preservation project NORDFERTIL; an additional 10 samples (from boys aged 5.5 ± 3.5 (mean ± SD) years, without an underlying pathology) in an internal biobank collection were used as controls.

PARTICIPANTS/MATERIALS SETTING METHODS

We obtained 49 testicular tissue samples from boys aged 0.8-13.4 years. Fresh samples (n = 11) were dissociated into single-cell suspensions and applied to a three-layer gradient culture system for organoid formation. Histological sections of another 28 samples obtained as part of the fertility preservation project NORDFERTIL, and 10 samples from a sample collection of a pathology biobank were used to evaluate the effects of prior exposure to alkylating agents on testicular samples. Testicular organoid formation was defined based on morphological features, such as compartmentalized structures showing cord formation, and protein expression of testicular cell-specific markers for germ and somatic cells was evaluated via immunohistochemical staining. Hormone secretion was analysed by specific enzyme-linked immunosorbent assays for testosterone and anti-Müllerian hormone (AMH) production.

MAIN RESULTS AND THE ROLE OF CHANCE

Our results revealed that 4 out of 11 prepubertal testicular samples formed TOs that showed compartmentalized cord-like structures surrounded by interstitial-like areas and increasing levels of both testosterone as well as AMH over a 7-day culture period. We observed that SOX9 expression was correlated positively with TO formation. Moreover, exposure to alkylating agents before biopsy was inversely correlated with SOX9 expression (P = 0.006).

LARGE SCALE DATA

N/A.

LIMITATIONS REASONS FOR CAUTION

Due to the limited amount of material available, only 11 out of the 39 pre- and peri-pubertal testicular tissue samples could be used for the organoid formation experiments. The testicular tissue samples obtained from a sample collection of the internal biobank of Department of Pathology, Karolinska University Hospital were considered normal and included in the study if no testicular pathology was reported. However, detailed information regarding previous medical treatments and/or testicular volumes of the patients included in this biobank was not available.

WIDER IMPLICATIONS OF THE FINDINGS

Our observations suggest that SOX9 expression may serve as a putative indicator of TO formation, indicating a critical role of Sertoli cells in promoting organoid formation, seminiferous tubule integrity, and testicular function in pre- and peri-pubertal testicular tissue.

STUDY FUNDING/COMPETING INTERESTS

This study was supported by grants from the Swedish Childhood Cancer Foundation (PR2019-0123; PR2022-0115; TJ2020-0023) (J.-B.S.), Finnish Cancer Society (K.J.), Finnish Foundation for Paediatric Research (K.J.), Swedish Research Council (2018-03094; 2021-02107) (J.-B.S.), and Birgitta and Carl-Axel Rydbeck's Research Grant for Paediatric Research (2020-00348; 2020-00335; 2021-00073; 2022-00317) (J.-B.S. and K.J.). Y.C. and Y.Y. received a scholarship from the Chinese Scholarship Council. J.P.A-L. was supported by a Starting Grant in Medicine and Health (2022-01467) from the Swedish Research Council. R.T.M. was supported by a UKRI Future Leaders Fellowship (MR/S017151/1). The MRC Centre for Reproductive Health was supported by an MRC Centre Grant (MR/N022556/1). The authors declare no competing interests.

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

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

Molecular phenotyping of domestic cat (Felis catus) testicular cells across postnatal development - A model for wild felids

Molecular characterisation of testicular cells is a pivotal step towards a profound understanding of spermatogenesis and developing assisted reproductive techniques (ARTs) based on germline preservation. To enable the identification of testicular somatic and spermatogenic cell types in felids, we investigated the expression of five molecular markers at the protein level in testes from domestic cats (Felis catus) at different developmental phases (prepubertal, pubertal I and II, postpubertal I and II) classified by single-cell ploidy analysis. Our findings indicate a prominent co-labelling for two spermatogonial markers, UCHL1 and FOXO1, throughout postnatal testis development. Smaller subsets of UCHL1 or FOXO1 single-positive spermatogonia were also evident, with the FOXO1 single-positive spermatogonia predominantly observed in prepubertal testes. As expected, DDX4+ germ cells increased in numbers beginning in puberty, reaching a maximum at adulthood (post-pubertal phase), corresponding to the sequential appearance of labelled spermatogonia, spermatocytes and spermatids. Furthermore, we identified SOX9+ Sertoli cells and CYP17A1+ Leydig cells in all of the developmental groups. Importantly, testes of African lion (Panthera leo), Sumatran tiger (Panthera tigris sumatrae), Chinese leopard (Panthera pardus japonesis) and Sudan cheetah (Acinonyx jubatus soemmeringii) exhibited conserved labelling for UCHL1, FOXO1, DDX4, SOX9 and CYP17A1. The present study provides fundamental information about the identity of spermatogenic and somatic testicular cell types across felid development that will be useful for developing ART approaches to support endangered felid conservation.

Defining Gene Function in Spermatogonial Stem Cells Through Conditional Knockout Approaches

Mammalian male fertility is maintained throughout life by a population of self-renewing mitotic germ cells known as spermatogonial stem cells (SSCs). Much of our current understanding regarding the molecular mechanisms underlying SSC activity is derived from studies using conditional knockout mouse models. Here, we provide a guide for the selection and use of mouse strains to develop conditional knockout models for the study of SSCs, as well as their precursors and differentiation-committed progeny. We describe Cre recombinase-expressing strains, breeding strategies to generate experimental groups, and treatment regimens for inducible knockout models and provide advice for verifying and improving conditional knockout efficiency. This resource can be beneficial to those aiming to develop conditional knockout models for the study of SSC development and postnatal function.

Mouse-human species differences in early testicular development and its implications

The mouse has been used as a model of human organogenesis with the tacit assumption that morphogenetic and molecular mechanisms in mice are translatable to human organogenesis. While many morphogenetic and molecular mechanisms are shared in mice and humans, many anatomic, morphogenetic, and molecular differences have been noted. Two critical gaps in our knowledge prevent meaningful comparisons of mouse versus human testicular development: (a) human testicular development is profoundly under-represented in the literature, and (b) an absence of a detailed day-by-day ontogeny of mouse testicular development from E11.5 to E16.5 encompassing the ambisexual stage to seminiferous cord formation. To address these deficiencies, histologic and immunohistochemical studies were pursued in comparable stages of mouse and human testicular development with a particular emphasis on Leydig, Sertoli and myoid cells through review of the literature and new observations. For example, an androgen-receptor-positive testicular medulla is present in the developing human testis but not in the developing mouse testis. The human testicular medulla and associated mesonephros were historically described as the source of Sertoli cells in seminiferous cords. Consistent with this idea, the profoundly androgen receptor (AR)-positive human testicular medulla was shown to be a zone of mesenchymal to epithelial transition and a zone from which AR-positive cells appear to migrate into the human testicular cortex. While mouse Sertoli and Leydig cells have been proposed to arise from coelomic epithelium, Sertoli (SOX9) or Leydig (HSD3B1) cell markers are absent from the immediate coelomic zone of the developing human testis, perhaps because Leydig and Sertoli cell precursors are undifferentiated when they egress from the coelomic epithelium. The origin of mouse and human myoid cells remains unclear. This study provides a detailed comparison of the early stages of testicular development in human and mouse emphasizing differences in developmental processes.

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

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

Ontogeny of mouse Sertoli, Leydig and peritubular myoid cells from embryonic day 10 to adulthood

We present a comprehensive description of the differentiating somatic cell types (Sertoli, Leydig, and peritubular myoid cells) of the mouse testis from embryonic day 10.5 (E10.5) to adulthood, postnatal day 60 (P60). Immunohistochemistry was used to analyze expression of: Sox9 (a Sertoli cell marker), 3βHSD-1 (a fetal Leydig cell marker), 3βHSD-6 (an adult Leydig cell marker), α-actin (a peritubular myoid cell marker), and androgen receptor (a marker of all three somatic cell types). The temporal-spatial expression of these markers was used to interrogate findings of earlier experimental studies on the origin of Sertoli, Leydig and peritubular myoid cells, as well as extend previous descriptive studies across a broader developmental period (E10.5-P60). Such comparisons demonstrate inconsistencies that require further examination and raise questions regarding conservation of developmental mechanisms across higher vertebrate species.

Transcriptomic Study of Spermatogenesis in the Testis of Hu Sheep and Tibetan Sheep

Numerous genes involved in male reproduction regulate testis development and spermatogenesis. In this study, the testis tissue transcriptome was used to identify candidate genes and key pathways associated with fecundity in sheep. Histological analysis of testis tissue using hematoxylin-eosin (HE) routine staining was performed for two sheep breeds. Overall, 466 differentially expressed genes (DEGs) were identified between Hu sheep (HS) and Tibetan sheep (TS) through RNA sequencing technology (RNA-Seq), including 226 upregulated and 240 downregulated genes. Functional analysis showed that several terms and pathways, such as "protein digestion and absorption", "cAMP signaling pathway", "focal adhesion", and "p53 signaling pathway" were closely related to testis development and spermatogenesis. Several genes (including COL1A1, COL1A2, COL3A1, SOX9, BCL2, HDC, and GGT5) were significantly enriched in these terms and pathways and might affect the reproduction of sheep by regulating the migration of spermatogenic cells, apoptosis of spermatogenic cells, and secretion of sterol hormones via testicular interstitial cells. Our results provide a theoretical basis for better understanding the molecular mechanisms of reproduction in sheep.

Adult Exposure to Di-N-Butyl Phthalate (DBP) Induces Persistent Effects on Testicular Cell Markers and Testosterone Biosynthesis in Mice

Studies indicate that phthalates are endocrine disruptors affecting reproductive health. One of the most commonly used phthalates, di-n-butyl phthalate (DBP), has been linked with adverse reproductive health outcomes in men, but the mechanisms behind these effects are still poorly understood. Here, adult male mice were orally exposed to DBP (10 or 100 mg/kg/day) for five weeks, and the testis and adrenal glands were collected one week after the last dose, to examine more persistent effects. Quantification of testosterone, androstenedione, progesterone and corticosterone concentrations by liquid chromatography-mass spectrometry showed that testicular testosterone was significantly decreased in both DBP treatment groups, whereas the other steroids were not significantly altered. Western blot analysis of testis revealed that DBP exposure increased the levels of the steroidogenic enzymes CYP11A1, HSD3β2, and CYP17A1, the oxidative stress marker nitrotyrosine, and the luteinizing hormone receptor (LHR). The analysis further demonstrated increased levels of the germ cell marker DAZL, the Sertoli cell markers vimentin and SOX9, and the Leydig cell marker SULT1E1. Overall, the present work provides more mechanistic understanding of how adult DBP exposure can induce effects on the male reproductive system by affecting several key cells and proteins important for testosterone biosynthesis and spermatogenesis, and for the first time shows that these effects persist at least one week after the last dose. It also demonstrates impairment of testosterone biosynthesis at a lower dose than previously reported.

Short-term exposure to perfluorotetradecanoic acid affects the late-stage regeneration of Leydig cells in adult male rats

Perfluorotetradecanoic acid (PFTeDA) is one of perfluoroalkyl substances widely found in the environment. PFTeDA may cause the dysfunction of male reproductive system. However, whether PFTeDA affects the regeneration of Leydig cells remains unclear. The objective of this study was to examine the effects of short-term exposure of PFTeDA on the late-stage maturation of Leydig cells. Fifty-four adult Sprague-Dawley male rats were daily gavaged with PFTeDA (0, 10, or 20 mg/kg body weight) for 10 days, and then were injected intraperitoneally with ethylene dimethane sulfonate (EDS, 75 mg/kg body weight/once) to ablate Leydig cells to induce their regeneration. On day 21 (early stage) and 56 (late stage) after EDS, hormone levels, gene expression, and protein levels were measured. PFTeDA did not affect the early stage of Leydig cell regeneration, because it had no effect on serum testosterone, luteinizing hormone, and follicle-stimulating hormone levels, Leydig cell number, and its gene and protein expression. PFTeDA significantly reduced serum testosterone level and down-regulated the expression of Leydig cell genes (Cyp11a1, Hsd3b1, Cyp17a1, Hsd17b3, Hsd11b1, and Insl3) and their proteins (CYP11A1, HSD3B1, CYP17A1, HSD17B3, and INSL3), decreased the phosphorylation of AKT1 and ERK1/2, as well as lowered sperm count in the epididymis at 20 mg/kg. In conclusion, short-term exposure to PFTeDA blocks the late-stage maturation of Leydig cells.

Helix-loop-helix protein ID4 expressed in bovine Sertoli cells

Stage- and cell type-specific biomarkers are important for understanding spermatogenesis in mammalian testis. The present study identified several testicular cell marker proteins in 6- and 24-month old bovine testes. In 6-month old bovine testes, spermatogonia and spermatocytes were detected but complete spermatogenesis occurred in 24-month old testes. The diameters of the seminiferous tubules increased significantly in the 24-month old testes compared with those in the 6-month old testes. Protein Gene Product 9.5 (PGP9.5), also known as the undifferentiated spermatogonium marker, and GATA4 (GATA binding protein 4), vimentin, and SOX9 (SRY-Box Transcription Factor 9) were detected in the basement membrane region. Interestingly, ID4 (inhibitor of DNA binding protein 4; previously known as the undifferentiated cell marker) proteins were located in the basement membrane region but their expression patterns were different from those of PGP9.5. Co-immunohistochemistry results showed that ID4 was detected in the Sertoli cells expressing vimentin and SOX9 in 6- and 24-month old bovine testes. This result indicated that ID4 is a putative biomarker of Sertoli cell in the bovine system, which is different from the rodent models. Thus, these results will contribute in understanding the process of spermatogenesis that is different in bovines compared to other species.

Long-Term Maintenance of Viable Adult Rat Sertoli Cells Able to Establish Testis Barrier Components and Function in Response to Androgens

A protocol for the isolation and long-term propagation of adult rat Sertoli cells (SCs) using conditional reprogramming (CR) was developed and the formation of tight junctions as an in vitro model for the blood testis barrier (BTB) was studied. Three pure primary SC lines were isolated successfully and maintained for several months without significant changes in expression levels of SC-typical markers such as SRY-box transcription factor 9 (SOX9), transferrin, clusterin, androgen receptor (AR), and GATA binding protein 1 (GATA1). In addition to AR expression, the tight junction proteins, zonula occludens-1 (ZO-1) and the junctional adhesion molecule-3 (JAM-3), were upregulated and the SC barrier integrity was enhanced by testosterone. Peritubular/myoid cells did not increase the tightness of the SC. The cytokines, interleukin-6 (IL-6), bone morphogenetic protein-2 (BMP2), and transforming growth factor beta-3 (TGF-β3), negatively affected the tightness of the SC barrier. We have established a protocol for the isolation and long-term propagation of highly pure primary adult rat SCs, which are able to respond to androgen treatments, to form tight junctions and to maintain the mRNA expression of SC-specific genes. By applying this new method, adult SCs can now be analyzed in more detail and might serve as an in vitro model for the study of many SC functions.

Mediterranean Pine Vole, Microtus duodecimcostatus: A Paradigm of an Opportunistic Breeder

Simple Summary

In temperate zones of the Earth, some mammalian species reproduce seasonally whereas others do it continuously. Other species are summer breeders in the north and winter breeders in the south. Thus, the reproductive pattern seems not to be a species-specific but a population-specific trait. We investigated the reproduction pattern of the Mediterranean pine vole, Microtus duodecimcostatus, in the area around the city of Granada in Southern Spain, and found that individuals living in wastelands reproduce seasonally whereas those living in close poplar plantations (just 8 km apart) reproduce throughout the year, as did voles captured in wastelands and kept in captivity. These animals represent thus a paradigm of an opportunistic breeder as particular individuals stop breeding or not, depending on the environmental conditions they face at any moment. Sexually inactive male voles undergo complete testis inactivation and their sperm production is halted. The immune system in active testes is depressed, a phenomenon known as “immune privilege” that protect germ cells from autoimmune attack. We studied gene activity in active and inactive testes and our results indicate that such an immune privilege is lost in inactive testes, suggesting an important role for this process during testis regression.

Abstract

Most mammalian species of the temperate zones of the Earth reproduce seasonally, existing a non-breeding period in which the gonads of both sexes undergo functional regression. It is widely accepted that photoperiod is the principal environmental cue controlling these seasonal changes, although several exceptions have been described in other mammalian species in which breeding depends on cues such as food or water availability. We studied the circannual reproductive cycle in males of the Mediterranean pine vole, Microtus duodecimcostatus, in the Southeastern Iberian Peninsula. Morphological, hormonal, functional, molecular and transcriptomic analyses were performed. As reported for populations of other species from the same geographic area, male voles captured in wastelands underwent seasonal testis regression in summer whereas, surprisingly, those living either in close poplar plantations or in our animal house reproduced throughout the year, showing that it is the microenvironment of a particular vole subpopulation what determines its reproductive status and that these animals are pure opportunistic, photoperiod-independent breeders. In addition, we show that several molecular pathways, including MAPK, are deregulated and that the testicular “immune privilege” is lost in the inactive testes, providing novel mechanisms linking seasonal testosterone reduction and testis regression.

Common markers of testicular Sertoli cells

INTRODUCTION

Sertoli cells play central roles in the development of testis formation in fetuses and the initiation and maintenance of spermatogenesis in puberty and adulthood, and disorders of Sertoli cell proliferation and/or functional maturation can cause male reproductive disorders at various life stages. It's well documented that various genes are either overexpressed or absent in Sertoli cells during the conversion of an immature, proliferating Sertoli cell to a mature, non-proliferating Sertoli cell, which are considered as Sertoli cell stage-specific markers. Thus, it is paramount to choose an appropriate Sertoli cell marker that will be used not only to identify the developmental, proliferative, and maturation of Sertoli cell status in the testis during the fetal period, prepuberty, puberty, or in the adult, but also to diagnose the mechanisms underlying spermatogenic dysfunction.

AREAS COVERED

In this review, we principally enumerated 5 categories of testicular Sertoli cell markers - including immature Sertoli cell markers, mature Sertoli cell markers, immature/mature Sertoli cell markers, Sertoli cell functional markers, and others.

EXPERT OPINION

By delineating the characteristics and applications of more than 20 Sertoli cell markers, this review provided novel Sertoli cell markers for the more accurate diagnosis and mechanistic evaluation of male reproductive disorders.

Bisphenol B stimulates Leydig cell proliferation but inhibits maturation in late pubertal rats

Bisphenol B (BPB) has been used as a substitute for bisphenol A (BPA) in plastic materials. Whether BPB disrupts the male reproductive system remains unknown. Here, we report the effect of BPB on Leydig cell maturation in late puberty. Male Sprague-Dawley (35 days old) rats were gavaged with BPB at 0, 10, 100, and 200 mg/kg/day for 21 days. BPB significantly reduced body and epididymis weight at 200 mg/kg. BPB markedly decreased serum testosterone levels at 100 and 200 mg/kg and serum luteinizing hormone and follicle-stimulating hormone levels at 200 mg/kg. BPB significantly increased Leydig cell number at 100 and 200 mg/kg, while down-regulating the expression of Leydig cell genes (Cyp11a1 and Hsd3b1) at ≥100 mg/kg and up-regulating the expression of Sertoli cell genes (Pdgfra, Fshr, Sox9) and cell cycle regulators (Pcna, Ccnb1, Cdk2, and Cdk4) at 10-200 mg/kg. BPB markedly increased the phosphorylation of AKT1, AKT2, and ERK1/2 at 200 mg/kg. BPB increased the proliferation of rat immature Leydig cells via promoting the S/M2 phase shift at 100 and 1000 nM after 24-h culture in vitro. In conclusion, BPB disrupts Leydig cell maturation in late puberty by increasing Leydig cell number while inhibiting its maturation.

Divergent Seasonal Reproductive Patterns in Syntopic Populations of Two Murine Species in Southern Spain, Mus spretus and Apodemus sylvaticus

Simple Summary

In temperate zones of the Earth, most species reproduce in seasons providing the most favourable environmental conditions. Producing gametes is expensive in energetical terms, so both males and females either reduce or abolish gametogenesis during the non-breeding period. We thoroughly studied the testes of sexually inactive males of two rodents, the wood mouse, Apodemus sylvaticus, and the Algerian mouse, Mus spretus, in southern Iberian peninsula. These populations are syntopic, that is, animals of the two species share their territories and resources, so one would expect them to show similar or identical seasonal reproduction patterns. Contrarily, we found that both species reproduce during most of the year, but wood mice stop breeding in the summer whereas Algerian mice do it in winter. These divergent seasonal breeding patterns imply that either very subtle animal features and/or environmental cues operate to determine reproduction timing and support the notion that multiple models of circannual reproduction patterns are possible for different populations of the same species, showing that the mechanisms controlling seasonal reproduction are in fact very plastic and fast evolving. Hence, small mammals probably have multiple ways available to get adapted to the unstable environmental conditions derived from the ongoing global climate change.

Abstract

In most mammals with seasonal reproduction, males undergo testis regression during the non-breeding period. We performed a morphological, hormonal, functional, and molecular study of the testes of sexually inactive males of two species of murine rodents, the wood mouse, Apodemus sylvaticus, and the Algerian mouse, Mus spretus, in syntopic populations of southern Iberian peninsula. Both species reproduce during most of the year, but wood mice stop breeding in the summer whereas Algerian mice do it in winter. Sexually inactive males of A. sylvaticus show complete testis regression with reduced levels of serum testosterone and abnormal distribution of cell-adhesion molecules. Contrarily, inactive males of M. spretus maintain almost normal spermotogenesis despite a significant reduction of androgenic function. The lack of an evident explanation for the divergent seasonal breeding patterns found in southern populations of A. sylvaticus and M. spretus, compared with northern ones, implies that very subtle species/population-specific features and/or non-conspicuous environmental cues probably operate to determine their seasonal breeding pattern. These results also support the notion that multiple models of circannual testis variation are possible for different populations of the same species, showing that the mechanisms controlling seasonal reproduction are in fact very plastic and fast evolving.

Generation of a hTERT-Immortalized Human Sertoli Cell Model to Study Transporter Dynamics at the Blood-Testis Barrier

The blood-testis barrier (BTB) formed by adjacent Sertoli cells (SCs) limits the entry of many chemicals into seminiferous tubules. Differences in rodent and human substrate-transporter selectivity or kinetics can misrepresent conclusions drawn using rodent in vitro models. Therefore, human in vitro models are preferable when studying transporter dynamics at the BTB. This study describes a hTERT-immortalized human SC line (hT-SerC) with significantly increased replication capacity and minor phenotypic alterations compared to primary human SCs. Notably, hT-SerCs retained similar morphology and minimal changes to mRNA expression of several common SC genes, including AR and FSHR. The mRNA expression of most xenobiotic transporters was within the 2-fold difference threshold in RT-qPCR analysis with some exceptions (OAT3, OCT3, OCTN1, OATP3A1, OATP4A1, ENT1, and ENT2). Functional analysis of the equilibrative nucleoside transporters (ENTs) revealed that primary human SCs and hT-SerCs predominantly express ENT1 with minimal ENT2 expression at the plasma membrane. ENT1-mediated uptake of [³H] uridine was linear over 10 min and inhibited by NBMPR with an IC₅₀ value of 1.35 ± 0.37 nM. These results demonstrate that hT-SerCs can functionally model elements of transport across the human BTB, potentially leading to identification of other transport pathways for xenobiotics, and will guide drug discovery efforts in developing effective BTB-permeable compounds.

Association study between single-nucleotide variants rs12097821, rs2477686, and rs10842262 and idiopathic male infertility risk in Serbian population with meta-analysis

PURPOSE

A genome-wide association study conducted in the Han Chinese population identified three single nucleotide variants rs12097821, rs2477686, and rs10842262 as being significantly associated with non-obstructive azoospermia. Our aim was to evaluate the possible association between these susceptibility loci and idiopathic male infertility risk in the Serbian population.

METHODS

A case-control study was conducted on 431 male individuals from the Serbian population divided into two groups. The case group consisted of 208 males diagnosed with oligoasthenozoospermia or non-obstructive azoospermia, while the control group involved 223 fertile men who have fathered at least one child.

RESULTS

According to codominant (P_codom = 0.048, OR_codom = 0.57, 95%CI 0.35-0.92) and overdominant (P_overdom = 0.017, OR_overdom = 0.62, 95%CI 0.42-0.92) genetic models, rs10842262 was found to be associated with male infertility. Stratifying infertile men according to diagnosis yielded statistically significant results for non-obstructive azoospermia cases under multiple genetic models (P_codom = 0.038, OR_codom = 0.47, 95%CI 0.26-0.85; P_dom = 0.031, OR_dom = 0.53, 95%CI 0.30-0.94; P_overdom = 0.016, OR_overdom = 0.55, 95%CI 0.33-0.90). Minor allele C of rs2477686 genetic variant was shown to be associated with the reduced risk of oligoasthenozoospermia under the log-additive genetic model (P = 0.03, OR = 0.69, 95%CI 0.50-0.97). The results of the meta-analysis indicate both rs2477686 and rs10842262 to be associated with male infertility.

CONCLUSION

Our results show variants rs2477686 and rs10842262 to be significantly associated with male infertility in the Serbian population. Nevertheless, case-control studies in other populations are needed to validate their association with infertility in males diagnosed with oligoasthenozoospermia and non-obstructive azoospermia.

Characterization of rodent Sertoli cell primary cultures

Sertoli cells play a vital role in spermatogenesis by offering physical and nutritional support to the differentiating male germ cells. They form the blood-testis barrier and secrete growth factors essential for germ cell differentiation. Sertoli cell primary cultures are critical for understanding the regulation of spermatogenesis; however, obtaining pure cultures has been a challenge. Rodent Sertoli cell isolation protocols do not rule out contamination by the interstitial or connective tissue cells. Sertoli cell-specific markers could be helpful, but there is no consensus. Vimentin, the most commonly used marker, is not specific for Sertoli cells since its expression has been reported in peritubular myoid cells, mesenchymal stem cells, fibroblasts, macrophages, and endothelial cells, which contaminate Sertoli cell preparations. Markers based on transcription and growth factors also have limitations. Thus, the impediment to obtaining pure Sertoli cell cultures pertains to both the method of isolation and marker usage. The aim of this review is to discuss improvements to current methods of rodent Sertoli cell primary cultures, assess the properties of prepubertal versus mature Sertoli cell cultures, and propose steps to improve cellular characterization. Potential benefits of using contemporary approaches, including lineage tracing, specific cell ablation, and RNA-seq for obtaining Sertoli-specific transcript markers are discussed. Evaluating the specificity and applicability of these markers at the protein level to characterize Sertoli cells in culture would be critical. This review is expected to positively impact future work using primary cultures of rodent Sertoli cells.

Establishment and functional characterization of a murine primary Sertoli cell line deficient of connexin43

The Sertoli cell (SC) specific connexin43 (Cx43) knockout (SCCx43KO) mouse line is ideal to gain insight into the mechanistic gap junction formation in SC and the seminiferous epithelium. A method for developing primary SC cultures from these mice was established, validated and successfully characterized via polymerase chain reaction, immunohistochemistry, immunofluorescence (IF), and Western blots (WB). It was evident that both knockout (KO) and wild-type (WT) primary cell cultures were similar in morphology. These highly pure SC cultures were subjected to cell proliferation assays indicating no notable proliferation in cultures of both genotypes. Measurements of cell monolayer integrity indicated significant increases in transepithelial electrical resistance and consequently in tight junction expression of the KO cultures. Using semi-quantitative WB and IF, tight junction protein claudin-11 was analyzed. These results support a role for Cx43 in regulating blood-testis barrier (BTB) function, composition, and dynamics in vitro. Thus, the SC deficient Cx43 cell cultures may provide a valuable in vitro tool for a better understanding of the mechanistic role of Cx43 in spermatogenesis and BTB assembly.

Acute heat-treatment disrupts inhibin-related protein production and gene expression in the adult rat testis

Heat reversibly disrupts spermatogenesis, but the effects on Sertoli cell (SC) function and inhibin/activin-related proteins are less well-defined. Adult rat testis weights decreased by 40% within 2 weeks after heat-treatment (43 °C, 15 min), due to loss of pachytene spermatocytes and round spermatids. Coincident effects were reduced SC nuclear volume at one week and >50% reduction in expression of several critical SC genes (Inha, Cld11, Gja1, Tjp1, Cldn3) by 2 weeks. Leydig cell steroidogenic enzymes, Cyp11a1, Hsd3b1, were also reduced. Activin gene expression was unaffected at this time, but expression of the activin-binding protein, follistatin (Fst), increased >2-fold. At 4-8 weeks, coincident with the recovery of spermatocytes and early spermatids, but progressive loss of elongated spermatids, most SC genes had recovered; however, testicular activin A was reduced and activin B increased. At 8 weeks, serum inhibin was decreased and, consequently, serum FSH increased. Crucially, germ cell damage was not associated with a significant inflammatory response. At 14 weeks, most testicular parameters had returned to normal, but testis weights remained slightly reduced. These data indicate that, following acute heat-treatment, expression of several key Sertoli and Leydig cell genes declined in parallel with the initial loss of meiotic germ cells, whereas activins were responsive to the subsequent loss of mature spermatids, leading to an increase in testicular activin B production relative to activin A.

The transcriptional regulator CBX2 and ovarian function: A whole genome and whole transcriptome approach

The chromobox homolog 2 (CBX2) was found to be important for human testis development, but its role in the human ovary remains elusive. We conducted a genome-wide analysis based on DNA adenine methyltransferase identification (DamID) and RNA sequencing strategies to investigate CBX2 in the human granulosa cells. Functional analysis revealed that CBX2 was upstream of genes contributing to ovarian function like folliculogenesis and steroidogenesis (i.e. ESR1, NRG1, AKR1C1, PTGER2, BMP15, BMP2, FSHR and NTRK1/2). We identified CBX2 regulated genes associated with polycystic ovary syndrome (PCOS) such as TGFβ, MAP3K15 and DKK1, as well as genes implicated in premature ovarian failure (POF) (i.e. POF1B, BMP15 and HOXA13) and the pituitary deficiency (i.e. LHX4 and KISS1). Our study provided an excellent opportunity to identify genes surrounding CBX2 in the ovary and might contribute to the understanding of ovarian physiopathology causing infertility in women.

Transcriptome-wide identification and characterization of the Sox gene family and microsatellites for Corbicula fluminea

The Asian clam, Corbicula fluminea, is a commonly consumed small freshwater bivalve in East Asia. However, available genetic information of this clam is still limited. In this study, the transcriptome of female C. fluminea was sequenced using the Illumina HiSeq 2500 platform. A total of 89,563 unigenes were assembled with an average length of 859 bp, and 36.7% of them were successfully annotated. Six members of Sox gene family namely SoxB1, SoxB2, SoxC, SoxD, SoxE and SoxF were identified. Based on these genes, the divergence time of C. fluminea was estimated to be around  476 million years ago. Furthermore, a total of 3,117 microsatellites were detected with a distribution density of 1:12,960 bp. Fifty of these microsatellites were randomly selected for validation, and 45 of them were successfully amplified with 31 polymorphic ones. The data obtained in this study will provide useful information for future genetic and genomic studies in C. fluminea.

Differential Regulation of TLE3 in Sertoli Cells of the Testes during Postnatal Development

Spermatogenesis is a process by which haploid cells differentiate from germ cells in the seminiferous tubules of the testes. TLE3, a transcriptional co-regulator that interacts with DNA-binding factors, plays a role in the development of somatic cells. However, no studies have shown its role during germ cell development in the testes. Here, we examined TLE3 expression in the testes during spermatogenesis. TLE3 was highly expressed in mouse testes and was dynamically regulated in different cell types of the seminiferous tubules, spermatogonia, spermatids, and Sertoli cells, but not in the spermatocytes. Interestingly, TLE3 was not detected in Sertoli cells on postnatal day 7 (P7) but was expressed from P10 onward. The microarray analysis showed that the expression of numerous genes changed upon TLE3 knockdown in a Sertoli cell line TM4. These include 1597 up-regulated genes and 1452 down-regulated genes in TLE3-knockdown TM4 cells. Ingenuity Pathway Analysis (IPA) showed that three factors were up-regulated and two genes were down-regulated upon TLE3 knockdown in TM4 cells. The abnormal expression of the three factors is associated with cellular malfunctions such as abnormal differentiation and Sertoli cell formation. Thus, TLE3 is differentially expressed in Sertoli cells and plays a crucial role in regulating cell-specific genes involved in the differentiation and formation of Sertoli cells during testicular development.

Pig SOX9: Expression profiles of Sertoli cell (SCs) and a functional 18 bp indel affecting testis weight

Sex determining region Y-box 9 (SOX9), an important member of the SRY- type HMGbox (SOX) gene family, plays an important role in the regulation of mammalian reproduction, including sex differentiation during the embryonic development stage and spermatogenesis after birth. To explore the roles of polymorphism and expression of the SOX9 gene in the development of testes, we analyzed the indel of SOX9 in pigs and the corresponding expression level of the SOX9 gene in 7-day and 5-month-old porcine Sertoli cells. Results revealed that the DD haplotype of SOX9 gene as well as the ID genotype were significantly associated with larger testicular weight, while the II haplotype was closely related to the smaller testicular weight. More importantly, the SOX9 gene expression of ID genotyped group was significantly higher than that in II genotyped group. Our results first revealed that the indel polymorphism and expression of SOX9 were significantly associated with pig reproduction traits indicating the critical roles of SOX9 gene in testes development. The study provides a new clue for understanding the regulation of animal reproductive activities.

The efficacy of chronic zinc oxide nanoparticles using on testicular damage in the streptozotocin-induced diabetic rat model

Testicular impairment is a common complication of Diabetes mellitus (DM). Zinc Oxide Nanoparticles (ZnO NPs) are a novel agent for Zn delivery with antidiabetic and antioxidant activities. However, few reports were recorded on it. The current study aimed to investigate the possible ameliorating effect of ZnO NPs treatment on testicular tissues alterations in streptozotocin (STZ)-induced diabetic rats. Therefore, thirty mature male Wistar rats were divided into three main groups: Control group (n = 18) was subdivided equally into three subgroups (negative control, vehicle and ZnO NPs), Diabetic group (n = 6) and ZnO NPs-treated diabetic group (n = 6). Induction of diabetes was done by a single intraperitoneal injection of STZ (60 mg/kg bw). The rats were orally treated by ZnO NPs (10 mg/kg bw) for 30 constitutive days. At the end of the experiment, blood glucose and serum testosterone levels were measured. Also, testicular tissues were obtained for histopathological investigations and immunohistochemical staining with anti-PCNA (proliferating cell marker), anti-ssDNA (apoptotic cell marker), anti-SOX9 (Sertoli cell marker), anti-Stella (spermatogonia marker), anti-STRA8 (preleptotene and early-leptotene spermatocytes marker), anti-DMC1 (leptotene and zygotene spermatocytes marker), anti-Dnmt3a (a marker for cells under DNA methylation) and anti-α-SMA (peritubular myoid cell marker). The biochemical analysis revealed that diabetes resulted in a significant elevation in blood glucose level and a reduction in serum testosterone level. Moreover, histopathological investigations revealed disorganized seminiferous epithelium and sever hyalinization with vacuolization of the testicular interstitium containing Leydig cells. The immunohistochemical findings support spermatogenesis impairment in the diabetic group. However, ZnO NPs treatment restores architecture of seminiferous epithelium and Leydig cells. Furthermore, more PCNA, SOX9, Stella, STRA8, DMC1 and Dnmt3a immunopositive cells with an improvement of peritubular α-SMA immunopositive expression, as well as few ssDNA-immunopositive cells were detected in the seminiferous epithelium. This study suggested the possible protective role of orally administered ZnO NPs on testicular alterations in the STZ-induced diabetic group via steroidogenesis and spermatogenesis enhancement. In addition, further researches are acquired for evaluation mechanism of ZnO NPs treatment via oral or parenteral routes in a dose-dependent manner to identify the more effective route and dose in the treatment of testicular diabetic complications.

Haploid Germ Cells Generated in Organotypic Culture of Testicular Tissue From Prepubertal Boys

While in mice various studies have described the completion of spermatogenesis in vitro using either organotypic culture of prepubertal testicular tissue or 3D culture of isolated cells, in humans it has not been possible to achieve germ cell differentiation from immature testicular tissue (ITT). In our study, we evaluated the ability of human ITT to differentiate via a long-term organotypic culture of frozen–thawed 1 mm³ testicular fragments from five prepubertal boys in two different culture media. Tissue and supernatants were analyzed at regular intervals up to day 139. Sertoli cell (SC) viability and maturation was evaluated using immunohistochemistry (IHC) for SOX9, GDNF, anti-Mullerian hormone (AMH) and androgen receptor (AR), and AMH concentration in supernatants. Spermatogonia (SG) and proliferating cells were identified by MAGE-A4 (for SG) and Ki67 (for proliferating cells) via immunohistochemistry (IHC). Apoptotic cells were studied by active caspase 3. To evaluate Leydig cell (LC) functionality testosterone was measured in the supernatants and steroidogenic acute regulatory protein (STAR) IHC was performed. Germ cell differentiation was evaluated on Hematoxylin-Eosin histological sections, via IHC for synaptonemal complex 3 (SYCP3) for spermatocytes, Protein boule-like (BOLL) for spermatocytes and round spermatids, angiotensin-converting enzyme (ACE), protamine 2 and transition protein 1 (for elongated spermatids) and via chromogenic in situ hybridization (CISH). We reported the generation of meiotic and postmeiotic cells after 16 days of culture, as shown by the histological analyses, the presence of differentiation markers and the increase of haploid germ cells. We showed SC viability and maturation by a decrease of AMH secretion in the supernatants (p ≤ 0.001) while the number of SOX9 positive cells did not show any variation. A decrease of spermatogonia (p ≤ 0.001) was observed. The number of apoptotic cells did not vary. LC functionality was shown by the increase in STAR expression (p ≤ 0.007) and a peak in testosterone secretion, followed by a reduction (p ≤ 0.001) with stabilization. According to our knowledge, this is the first report of generation of haploid cells in human ITT. Differentiating germ cells have to be further evaluated for their ability to complete differentiation, their fecundability and epigenetic characteristics.

Physiological implications of DHEAS-induced non-classical steroid hormone signaling

In the spermatogenic cell line GC-2, dehydroepiandrosterone sulfate (DHEAS), activates the Src/Ras/c-Raf/Erk1/2/CREB(ATF-1) signaling cascade. Since DHEAS is present in the gonads, and since spermatogenesis and maturation of spermatogonia to haploid spermatozoa requires activation of Erk1/2, the triggering of these signaling events by DHEAS might have physiological relevance. In the Sertoli cell line TM4, DHEAS-induces activation of Erk1/2, CREB, and ATF-1, stimulates expression of claudin-3 and claudin-5 and augments transepithelial resistance, indicating the formation of tight junctions between adjacent Sertoli cells. Thus, by influencing the formation and dynamics of tight junctions at the blood-testis barrier, which protects germ cells from cells of the immune system, DHEAS might play a crucial role in the regulation and maintenance of male fertility. In bEnd.3 brain-derived endothelial cells, DHEAS stimulates the expression of zonula occludens-1 and claudin-3 and promotes tight junction formation between neighboring cells, which at the blood-brain barrier protects the brain from harmful factors and cells. If DHEAS supports the integrity of the blood-brain barrier also in vivo, the current findings might lead to new strategies for the prevention or treatment of neurological disorders associated with barrier defects.

SETDB1 plays an essential role in maintenance of gonocyte survival in pigs

Histone methyltransferase SETDB1 suppresses gene expression and modulates heterochromatin formation through H3K9me2/3. Previous studies have revealed that SETDB1 catalyzes lysine 9 of histone H3 tri-methylation and plays essential roles in maintaining the survival of embryonic stem cells and spermatogonial stem cells in mice. However, the function of SETDB1 in porcine male germ cells remains unclear. The aim of the present study was to reveal the expression profile and function of SETDB1 in porcine germ cells. SETDB1 expression gradually increased during testis development. SETDB1 was strongly localized in gonocytes. Knockdown of SETDB1 gene expression led to gonocyte apoptosis and a decrease in H3K27me3, but no significant change in H3K9me3. These observations suggested that SETDB1 is a novel epigenetic regulator of porcine male germ cells, and contributes to the maintenance of gonocyte survival in pigs, probably due to the regulation of H3K27me3 rather than H3K9me3. These findings will provide a theoretical basis for the future study of epigenetic regulation of spermatogenesis.

Identification of a Specific Sertoli Cell Marker, Sox9, for Use in Transplantation

The immunoprivileged environment of the testes was first described in the 1930s, and the Sertoli cell was later identified as the main cell type responsible for this phenomenon. Recent work has examined the possibility of recreating this immunoprivileged environment at heterotopic sites using isolated Sertoli cells. These studies have focused on protection of pancreatic islets and neuronal cells from immune destruction in the hopes of reversing type I diabetes and Parkinson's disease. The absence of a definitive marker for identifying Sertoli cells at the transplant site has been an obstacle to this research. The current study examines the presence of a nuclear transcription factor, Sox9, which is preferentially expressed in Sertoli cells. Syngeneic Lewis rat Sertoli cells were transplanted into the renal subcapsular space and a subcutaneous site in Lewis female rats and examined histologically 21 days later. In addition, porcine Sertoli cells were transplanted into the renal subcapsular space in female SCID mice. Control testes and the transplant sites were examined immunohistochemically using an antibody to Sox9. The results from the study demonstrate that Sox9 expression is restricted to the Sertoli cells of the neonatal rat and porcine testis, indicating high homology between species. In addition, Sox9 expression was also observed in the testicular-like tubules that formed in both syngeneic and xenogeneic heterotopic transplants in rats and SCID mice. The Sox9 expression was restricted to the regions where Sertoli cells would be found in the native testis. These results suggest that the Sox9 protein is a useful marker in identifying Sertoli cells in heterotopic transplants in a manner similar to insulin as a marker for pancreatic islets.

Transient Hypothyroidism: Dual Effect on Adult-Type Leydig Cell and Sertoli Cell Development

Transient neonatal 6-propyl-2-thiouracil (PTU) induced hypothyroidism affects Leydig and Sertoli cell numbers in the developing testis, resulting in increased adult testis size. The hypothyroid condition was thought to be responsible, an assumption questioned by studies showing that uninterrupted fetal/postnatal hypothyroidism did not affect adult testis size. Here, we investigated effects of transient hypothyroidism on Leydig and Sertoli cell development, employing a perinatal iodide-deficient diet in combination with sodium perchlorate. This hypothyroidism inducing diet was continued until days 1, 7, 14, or 28 postpartum (pp) respectively, when the rats were switched to a euthyroid diet and followed up to adulthood. Continuous euthyroid and hypothyroid, and neonatal PTU-treated rats switched to the euthyroid diet at 28 days pp, were included for comparison. No effects on formation of the adult-type Leydig cell population or on Sertoli cell proliferation and differentiation were observed when the diet switched at/or before day 14 pp. However, when the diet was discontinued at day 28 pp, Leydig cell development was delayed similarly to what was observed in chronic hypothyroid rats. Surprisingly, Sertoli cell proliferation was 6- to 8-fold increased 2 days after the diet switch and remained elevated the next days. In adulthood, Sertoli cell number per seminiferous tubule cross-section and consequently testis weight was increased in this group. These observations implicate that increased adult testis size in transiently hypothyroid rats is not caused by the hypothyroid condition per se, but originates from augmented Sertoli cell proliferation as a consequence of rapid normalization of thyroid hormone concentrations.

Genome-wide profiling of DNA 5-hydroxymethylcytosine during rat Sertoli cell maturation

Sertoli cells have dual roles during the cells' lifetime. In the juvenile mammal, Sertoli cells proliferate and create the structure of the testis, and during puberty they cease to proliferate and take on the adult role of supporting germ cells through spermatogenesis. Accordingly, many genes expressed in Sertoli cells during testis formation are repressed during spermatogenesis. 5-Hydroxymethylcytosine (5hmC) is a DNA modification enzymatically generated from 5mC and present in all investigated mammalian tissues at varying levels. Using mass spectrometry and immunofluorescence staining we identified a substantial Sertoli cell-specific global 5hmC increase during rat puberty. Chemical labeling, pull-down and sequencing of 5hmC-containing genomic DNA from juvenile and adult rat Sertoli cells revealed that genes that lose or gain 5hmC belong to different functional pathways and mirror the functions of the cells in the two different states. Loss of 5hmC is associated with genes involved in development and cell structure, whereas gain of 5hmC is associated with genes involved in cellular pathways pertaining to the function of the adult Sertoli cells. This redistribution during maturation shows that 5hmC is a dynamic nucleotide modification, correlated to gene expression.

The production of glial cell line-derived neurotrophic factor by human sertoli cells is substantially reduced in sertoli cell-only testes

STUDY QUESTION

Do human Sertoli cells in testes that exhibit the Sertoli cell-only (SCO) phenotype produce substantially less glial cell line-derived neurotrophic factor (GDNF) than Sertoli cells in normal testes?

SUMMARY ANSWER

In human SCO testes, both the amounts of GDNF mRNA per testis and the concentration of GDNF protein per Sertoli cell are markedly reduced as compared to normal testes.

WHAT IS KNOWN ALREADY

In vivo, GDNF is required to sustain the numbers and function of mouse spermatogonial stem cells (SSCs) and their immediate progeny, transit-amplifying progenitor spermatogonia. GDNF is expressed in the human testis, and the ligand-binding domain of the GDNF receptor, GFRA1, has been detected on human SSCs. The numbers and/or function of these stem cells are markedly reduced in some infertile men, resulting in the SCO histological phenotype.

STUDY DESIGN, SIZE, AND DURATION

We determined the numbers of human spermatogonia per mm2 of seminiferous tubule surface that express GFRA1 and/or UCHL1, another marker of human SSCs. We measured GFRA1 mRNA expression in order to document the reduced numbers and/or function of SSCs in SCO testes. We quantified GDNF mRNA in testes of humans and mice, a species with GDNF-dependent SSCs. We also compared GDNF mRNA expression in human testes with normal spermatogenesis to that in testes exhibiting the SCO phenotype. As controls, we also measured transcripts encoding two other Sertoli cell products, kit ligand (KITL) and clusterin (CLU). Finally, we compared the amounts of GDNF per Sertoli cell in normal and SCO testes.

PARTICIPANTS/MATERIALS SETTING METHODS

Normal human testes were obtained from beating heart organ donors. Biopsies of testes from men who were infertile due to maturation arrest or the SCO phenotype were obtained as part of standard care during micro-testicular surgical sperm extraction. Cells expressing GFRA1, UCHL1 or both on whole mounts of normal human seminiferous tubules were identified by immunohistochemistry and confocal microscopy and their numbers were determined by image analysis. Human GDNF mRNA and GFRA1 mRNA were quantified by use of digital PCR and Taqman primers. Transcripts encoding mouse GDNF and human KITL, CLU and 18 S rRNA, used for normalization of data, were quantified by use of real-time PCR and Taqman primers. Finally, we used two independent methods, flow cytometric analysis of single cells and ELISA assays of homogenates of whole testis biopsies, to compare amounts of GDNF per Sertoli cell in normal and SCO testes.

MAIN RESULTS AND THE ROLE OF CHANCE

Normal human testes contain a large population of SSCs that express GFRA1, the ligand-binding domain of the GDNF receptor. In human SCO testes, GFRA1 mRNA was detected but at markedly reduced levels. Expression of GDNF mRNA and the amount of GDNF protein per Sertoli cell were also significantly reduced in SCO testes. These results were observed in multiple, independent samples, and the reduced amount of GDNF in Sertoli cells of SCO testes was demonstrated using two different analytical approaches.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

There currently are no approved protocols for the in vivo manipulation of human testis GDNF concentrations. Thus, while our data suggest that insufficient GDNF may be the proximal cause of some cases of human male infertility, our results are correlative in nature.

WIDER IMPLICATIONS OF THE FINDINGS

We propose that insufficient GDNF expression may contribute to the infertility of some men with an SCO testicular phenotype. If their testes contain some SSCs, an approach that increases their testicular GDNF concentrations might expand stem cell numbers and possibly sperm production.

STUDY FUNDING/COMPETING INTEREST(S)

This research was funded by the Eunice Kennedy Shriver National Institute for Child Health and Human Development, National Centers for Translational Research in Reproduction and Infertility Program (NCTRI) Grant 1R01HD074542-04, as well as grants R01 HD076412-02 and P01 HD075795-02 and the U.S.-Israel Binational Science Foundation. Support for this research was also provided by NIH P50 HD076210, the Robert Dow Foundation, the Frederick & Theresa Dow Wallace Fund of the New York Community Trust and the Brady Urological Foundation. There are no competing interests.

Expressional changes of AMH signaling system in the quail testis induced by photoperiod

Gonadal sex differentiation proceeds by the interplay of various genes including the transcription factors and secretory factors in a complex network. The sex-differentiating genes are expressed not only during early sex differentiation but also throughout the gonadal development and even in the adult gonads. In addition, the evidence that they actually function in the adult gonads have been accumulated from the studies using the conditional knockout mice. However, many previous studies were focused on one single gene though those genes function in a network. In this study, the expressions of various sex-differentiating genes were analyzed simultaneously in the adult testis of the Japanese quail (Coturnix japonica), whose testicular functions are dramatically changed by altering the photoperiod, to elucidate the roles of them in the adult gonad. Anti-Müllerian hormone (AMH) was significantly upregulated in the regressed testis induced by the short-day condition. The expressions of the transcription factors that promoteAMHexpression in mammals (SF1,SOX9,WT1andGATA4) were also increased in the regressed testis. Moreover, AMH receptor (AMHR2) showed similar expression pattern to its ligand. We also analyzed the expressions of other transforming growth factor beta (TGFB) superfamily members and their receptors. The expressions of the ligands and receptors of TGFB family, and follistatin and betaglycan in addition to inhibin subunits were increased in the regressed testis. These results suggest that AMH is involved in the adult testicular functions of the Japanese quail together with other TGFB superfamily members.

Methylation of the Sox9 and Oct4 promoters and its correlation with gene expression during testicular development in the laboratory mouse

Sox9 and Oct4 are two important regulatory factors involved in mammalian development. Sox9, a member of the group E Sox transcription factor family, has a crucial role in the development of the genitourinary system, while Oct4, commonly known as octamer binding transcription factor 4, belongs to class V of the transcription family. The expression of these two proteins exhibits a dynamic pattern with regard to their expression sites and levels. The aim of this study was to investigate the role of de novo methylation in the regulation of the tissue- and site-specific expression of these proteins. The dynamics of the de novo methylation of 15 CpGs and six CpGs in Sox9 and Oct4 respectively, was studied with sodium bisulfite genomic DNA sequencing in mouse testis at different developmental stages. Consistent methylation of three CpGs was observed in adult ovary in which the expression of Sox9 was feeble, while the level of methylation in somatic tissue was greater in Oct4 compared to germinal tissue. The promoter-chromatin status of Sox9 was also studied with a chromatin immune-precipitation assay.

Sox9 and Sox8 protect the adult testis from male-to-female genetic reprogramming and complete degeneration

The new concept of mammalian sex maintenance establishes that particular key genes must remain active in the differentiated gonads to avoid genetic sex reprogramming, as described in adult ovaries after Foxl2 ablation. Dmrt1 plays a similar role in postnatal testes, but the mechanism of adult testis maintenance remains mostly unknown. Sox9 and Sox8 are required for postnatal male fertility, but their role in the adult testis has not been investigated. Here we show that after ablation of Sox9 in Sertoli cells of adult, fertile Sox8(-/-) mice, testis-to-ovary genetic reprogramming occurs and Sertoli cells transdifferentiate into granulosa-like cells. The process of testis regression culminates in complete degeneration of the seminiferous tubules, which become acellular, empty spaces among the extant Leydig cells. DMRT1 protein only remains in non-mutant cells, showing that SOX9/8 maintain Dmrt1 expression in the adult testis. Also, Sox9/8 warrant testis integrity by controlling the expression of structural proteins and protecting Sertoli cells from early apoptosis. Concluding, this study shows that, in addition to its crucial role in testis development, Sox9, together with Sox8 and coordinately with Dmrt1, also controls adult testis maintenance.

Dehydroepiandrosterone Sulfate Stimulates Expression of Blood-Testis-Barrier Proteins Claudin-3 and -5 and Tight Junction Formation via a Gnα11-Coupled Receptor in Sertoli Cells

Dehydroepiandrosterone sulfate (DHEAS) is a circulating sulfated steroid considered to be a pro-androgen in mammalian physiology. Here we show that at a physiological concentration (1 μM), DHEAS induces the phosphorylation of the kinase Erk1/2 and of the transcription factors CREB and ATF-1 in the murine Sertoli cell line TM4. This signaling cascade stimulates the expression of the tight junction (TJ) proteins claudin-3 and claudin-5. As a consequence of the increased expression, tight junction connections between neighboring Sertoli cells are augmented, as demonstrated by measurements of transepithelial resistance. Phosphorylation of Erk1/2, CREB, or ATF-1 is not affected by the presence of the steroid sulfatase inhibitor STX64. Erk1/2 phosphorylation was not observed when dehydroepiandrosterone (DHEA) was used instead of DHEAS. Abrogation of androgen receptor (AR) expression by siRNA did not affect DHEAS-stimulated Erk1/2 phosphorylation, nor did it change DHEAS-induced stimulation of claudin-3 and claudin-5 expression. All of the above indicate that desulfation and conversion of DHEAS into a different steroid hormone is not required to trigger the DHEAS-induced signaling cascade. All activating effects of DHEAS, however, are abolished when the expression of the G-protein Gnα11 is suppressed by siRNA, including claudin-3 and -5 expression and TJ formation between neighboring Sertoli cells as indicated by reduced transepithelial resistance. Taken together, these results are consistent with the effects of DHEAS being mediated through a membrane-bound G-protein-coupled receptor interacting with Gnα11 in a signaling pathway that resembles the non-classical signaling pathways of steroid hormones. Considering the fact that DHEAS is produced in reproductive organs, these findings also suggest that DHEAS, by acting as an autonomous steroid hormone and influencing the formation and dynamics of the TJ at the blood-testis barrier, might play a crucial role for the regulation and maintenance of male fertility.

The Sertoli cell: one hundred fifty years of beauty and plasticity

It has been one and a half centuries since Enrico Sertoli published the seminal discovery of the testicular 'nurse cell', not only a key cell in the testis, but indeed one of the most amazing cells in the vertebrate body. In this review, we begin by examining the three phases of morphological research that have occurred in the study of Sertoli cells, because microscopic anatomy was essentially the only scientific discipline available for about the first 75 years after the discovery. Biochemistry and molecular biology then changed all of biological sciences, including our understanding of the functions of Sertoli cells. Immunology and stem cell biology were not even topics of science in 1865, but they have now become major issues in our appreciation of Sertoli cell's role in spermatogenesis. We end with the universal importance and plasticity of function by comparing Sertoli cells in fish, amphibians, and mammals. In these various classes of vertebrates, Sertoli cells have quite different modes of proliferation and epithelial maintenance, cystic vs. tubular formation, yet accomplish essentially the same function but in strikingly different ways.

Blood-testis barrier and Sertoli cell function: lessons from SCCx43KO mice

The gap junction protein connexin43 (CX43) plays a vital role in mammalian spermatogenesis by allowing for direct cytoplasmic communication between neighbouring testicular cells. In addition, different publications suggest that CX43 in Sertoli cells (SC) might be important for blood-testis barrier (BTB) formation and BTB homeostasis. Thus, through the use of the Cre-LoxP recombination system, a transgenic mouse line was developed in which only SC are deficient of the gap junction protein, alpha 1 (Gja1) gene. Gja1 codes for the protein CX43. This transgenic mouse line has been commonly defined as the SC specific CX43 knockout (SCCx43KO) mouse line. Within the seminiferous tubule, SC aid in spermatogenesis by nurturing germ cells and help them to proliferate and mature. Owing to the absence of CX43 within the SC, homozygous KO mice are infertile, have reduced testis size, and mainly exhibit spermatogenesis arrest at the level of spermatogonia, seminiferous tubules containing only SC (SC-only syndrome) and intratubular SC-clusters. Although the SC specific KO of CX43 does not seem to have an adverse effect on BTB integrity, CX43 influences BTB composition as the expression pattern of different BTB proteins (like OCCLUDIN, β-CATENIN, N-CADHERIN, and CLAUDIN11) is altered in mutant males. The supposed roles of CX43 in dynamic BTB regulation, BTB assembly and/or disassembly and its possible interaction with other junctional proteins composing this unique barrier are discussed. Data collectively indicate that CX43 might represent an important regulator of dynamic BTB formation, composition and function.

Sry-Independent Overexpression of Sox9 Supports Spermatogenesis and Fertility in the Mouse

The Y chromosome gene Sry is responsible for sex determination in mammals and initiates a cascade of events that direct differentiation of bipotential genital ridges toward male-specific fate. Sox9 is an autosomal gene and a primary downstream target of SRY. The activation of Sox9 in the absence of Sry is sufficient for initiation of male-specific sex determination. Sry-to-Sox9 replacement has mostly been studied in the context of sex determination during early embryogenesis. Here, we tested whether Sry-to-Sox9 replacement affects male fertility in adulthood. We examined males with the Y chromosome carrying a deletion removing the endogenous Sry, with testes determination driven either by the Sox9 (XY(Tdym1)Sox9) or the Sry (XY(Tdym1)Sry) transgenes as well as wild-type males (XY). XY(Tdym1)Sox9 males had reduced testes size, altered testes shape and vasculature, and increased incidence of defects in seminiferous epithelium underlying the coelomic blood vessel region when compared to XY(Tdym1)Sry and XY. There were no differences between XY(Tdym1)Sry and XY(Tdym1)Sox9 males in respect to sperm number, motility, morphology, and ability to fertilize oocytes in vitro, but for some parameters, transgenic males were impaired when compared to XY. In fecundity trials, XY(Tdym1)Sry, XY(Tdym1)Sox9, and XY males yielded similar average numbers of pups and litters. Overall, our findings support that males lacking the testis determinant Sry can be fertile and reinforce the notion that Sry does not play a role in mature gonads. Although transgenic Sox9 overexpression in the absence of Sry results in certain testicular abnormalities, it does not translate into fertility impairment.

Porcine SOX9 Gene Expression Is Influenced by an 18 bp Indel in the 5'-Untranslated Region

Sex determining region Y-box 9 (SOX9) is an important regulator of sex and skeletal development and is expressed in a variety of embryonal and adult tissues. Loss or gain of function resulting from mutations within the coding region or chromosomal aberrations of the SOX9 locus lead to a plethora of detrimental phenotypes in humans and animals. One of these phenotypes is the so-called male-to-female or female-to-male sex-reversal which has been observed in several mammals including pig, dog, cat, goat, horse, and deer. In 38,XX sex-reversal French Large White pigs, a genome-wide association study suggested SOX9 as the causal gene, although no functional mutations were identified in affected animals. However, besides others an 18bp indel had been detected in the 5′-untranslated region of the SOX9 gene by comparing affected animals and controls. We have identified the same indel (Δ18) between position +247bp and +266bp downstream the transcription start site of the porcine SOX9 gene in four other pig breeds; i.e., German Large White, Laiwu Black, Bamei, and Erhualian. These animals have been genotyped in an attempt to identify candidate genes for porcine inguinal and/or scrotal hernia. Because the 18bp segment in the wild type 5′-UTR harbours a highly conserved cAMP-response element (CRE) half-site, we analysed its role in SOX9 expression in vitro. Competition and immunodepletion electromobility shift assays demonstrate that the CRE half-site is specifically recognized by CREB. Both binding of CREB to the wild type as well as the absence of the CRE half-site in Δ18 reduced expression efficiency in HEK293T, PK–15, and ATDC5 cells significantly. Transfection experiments of wild type and Δ18 SOX9 promoter luciferase constructs show a significant reduction of RNA and protein levels depending on the presence or absence of the 18bp segment. Hence, the data presented here demonstrate that the 18bp indel in the porcine SOX9 5′-UTR is of functional importance and may therefore indeed be a causative variation in SOX9 associated traits.

Long-term culture and analysis of cashmere goat Sertoli cells

Sertoli cells have important functions in the testis for spermatogenesis. Thus, Sertoli cell culture systems have been established in many animals, such as rat, mouse, human, dog, cow, and pig, but a goat culture has not been reported. This study describes the isolation and culture of Sertoli cells from 3- to 4-month-old cashmere goat (Capra hircus) testes. These proliferative cells were expanded for 20 passages and repeatedly cryopreserved in vitro, in contrast to previous study in human, of which maintain steady growth for up to seven passages and only passages 1 to 5 could be refrozen. The microstructure and ultrastructure of the culture were typical of Sertoli cells, bearing irregular nuclei and a cytoplasm that was rich in smooth and rough endoplasmic reticulum, mitochondria, Golgi, lysosomes, lipid drops, and glycogenosomes. By immunofluorescence analysis, the all cells expressed SRY-related HMG box gene 9 (Sox9). Growth curves and 5-bromo-2'-deoxyuridine (BrdU) incorporation were used to analyze the proliferation of the cultured cells. With increasing passage times, the proliferation of the Sertoli cells declined, but the transcription of glial cell-derived neurotrophic factor (GDNF), stem cell factor (SCF), and β1-integrin was constant. By flow cytometry, the cells retained the ability to proliferate after 5 yr of cryopreservation. Thus, cashmere goat Sertoli cells have significant proliferative potential in vitro, expressing germ cell regulatory factors and have important applications in studying Sertoli cell-germ cell interactions, spermatogenesis, reproductive toxicology, and male infertility.

Temporal changes in histomorphology and gene expression in goat testes during postnatal development

Testicular cell proliferation and differentiation is critical for development of normal testicular function and male reproductive maturity. The objective of the current study was to evaluate histoarchitecture and expression of genes marking specific cells and important functions as well as testosterone production of the developing goat testes. Testes were harvested from Alpine bucks at 0, 2, 4, 6, and 8 mo of age (n = 5/age group). Paired testes weight increased from 2 to 4 (P < 0.001) and 4 to 6 mo (P < 0.01). The greatest increases in seminiferous tubule and lumen diameters and height of the seminiferous epithelium occurred between 2 and 4 mo (P < 0.001). Genes expressed in haploid germ cells (Protamine1 [PRM1], Outer Dense Fiber protein 2 [ODF2], and Stimulated by Retinoic Acid gene 8 [STRA8]) increased dramatically at the same time (P < 0.001). Expression of other genes decreased (P < 0.05) during testicular maturation. These genes included P450 side chain cleavage (CYP11A1), Sex determining region Y-box 9 (SOX9), Insulin-like Growth Factor 1 Receptor (IGF1R), and Heat Shock Protein A8 (HSPA8). The Glutathione S-Transferase A3 (GSTA3) gene, whose product was recently recognized as a primary enzyme involved in isomerization of androstenedione in man and livestock species including goats, sheep, cattle, pigs, and horses, uniquely peaked in expression at 2 mo (P < 0.05). Follicle-Stimulating Hormone Receptor (FSHR) mRNA abundance tended to steadily decrease with age (P = 0.1), while Luteinizing Hormone Receptor (LHCGR) mRNA abundance in testes was not significantly different across the ages. Testosterone content per gram of testicular tissue varied among individuals. However, testosterone content per testis tended to increase at 6 mo (P = 0.06). In conclusion, major changes in cellular structure and gene expression in goat testes were observed at 4 mo of age, when spermatogenesis was initiated. Male goats mature rapidly and represent a good model species for the study of agents that enhance or impair development of testicular functions.

The battle of the sexes for stroke therapy: female- versus male-derived stem cells

Cell therapy is a major discipline of regenerative medicine that has been continually growing over the last two decades. The aging of the population necessitates discovery of therapeutic innovations to combat debilitating disorders, such as stroke. Menstrual blood and Sertoli cells are two gender-specific sources of viable transplantable cells for stroke therapy. The use of autologous cells for the subacute phase of stroke offers practical clinical application. Menstrual blood cells are readily available, display proliferative capacity, pluripotency and angiogenic features, and, following transplantation in stroke models, have the ability to migrate to the infarct site, regulate the inflammatory response, secrete neurotrophic factors, and have the possibility to differentiate into neural lineage. Similarly, the testis-derived Sertoli cells secrete many growth and trophic factors, are highly immunosuppressive, and exert neuroprotective effects in animal models of neurological disorders. We highlight the practicality of experimental and clinical application of menstrual blood cells and Sertoli cells to treat stroke, from cell isolation and cryopreservation to administration.

The testis of greater white-toothed shrew Crocidura russula in Southern European populations: a case of adaptive lack of seasonal involution?

Males of all seasonal breeding mammals undergo circannual periods of testis involution resulting in almost complete ablation of the germinative epithelium. We performed a morphometric, histological, hormonal, and gene-expression study of the testes from winter and summer males of the greater white-toothed shrew, Crocidura russula, in populations of the southeastern Iberian Peninsula. Unexpectedly, we found no significant differences between the two study groups. Surprisingly, female data confirmed a non-breeding period in the summer, evidencing that males retain full testis function even when most females are not receptive. This situation, which has not been described before, does not occur in northern populations of the same species where, in addition, the reproductive cycle is inverted with respect to those in the south, as the non-breeding period occurs in winter instead in summer. Considering that the non-reproductive period shortens at lower latitude locations, we hypothesize that in southern populations the non-breeding period is short enough to make testis regression inefficient in terms of energy savings, because: (1) testes of C. russula are very small, a condition derived from their monogamy that implies low investment in spermatogenesis; and (2) the spermatogenic cycle of this species is slow and long. The inverted seasonal breeding cycle and the lack of seasonal testis regression described here are new adaptive processes that deserve further research, and provide evidence that the genetic and hormonal mechanisms controlling reproduction timing in mammals are more plastic and versatile than initially suspected.

Effect of zearalenone on reproductive parameters and expression of selected testicular genes in mice

We tested the effect of two different concentrations (150μg/l and 0.15μg/l) of mycotoxin zearalenone (ZEA) on the reproductive parameters and expression of testicular genes in male mice. In adult males, no reduction of body or reproductive organ weight was observed, and the seminiferous tubules were morphologically normal with ongoing spermatogenesis. However, we found decreased sperm concentration, increase of morphologically abnormal spermatozoa and increased binding of apoptotic marker annexin V. This study was also focused on the evaluation of gene expression profiles of 28 genes playing important roles during the processes occurring in the testicular tissue. We detected changes in the expression of genes important for proper spermatogenesis. Surprisingly, we observed a stronger effect after exposure to the lower dose of ZEA.

Up-regulation of SOX9 in sertoli cells from testiculopathic patients accounts for increasing anti-mullerian hormone expression via impaired androgen receptor signaling

Background

Testosterone provokes Sertoli cell maturation and represses AMH production. In adult patients with Sertoli-cells-only syndrome (SCOS) and androgen insensitivity syndrome (AIS), high level of AMH expression is detected in Sertoli cells due to defect of androgen/AR signaling.

Objective

We postulated that up-regulation of SOX9 due to impairment of androgen/AR signaling in Sertoli cells might explain why high level of anti-Mullerian hormone (AMH) expression occur in these testiculopathic patients.

Methods

Biological research of testicular specimens from men with azoospermia or mouse. The serum hormone levels were studied in 23 men with obstructive azoospermia, 33 men with SCOS azoospermia and 21 volunteers with normal seminograms during a period of 4 years.

Immunohistochemical staining and reverse-transcription PCR were used to examine the relationships among AR, SOX9 and AMH expression in adult human and mouse testes. The ability of AR to repress the expression of SOX9 and AMH was evaluated in vitro in TM4 Sertoli cells and C3H10T1/2 cells.

Results

SCOS specimens showed up-regulation of SOX9 and AMH proteins but down-regulation of AR proteins in Sertoli cells. The mRNA levels of AR were significantly lower and the SOX9, AMH mRNA levels higher in all SCOS patients compared to controls (P< 0.05). The testosterone levels in the SCOS patients were within the normal range, but most were below the median of the controls. Furthermore, our invitro cell line experiments demonstrated that androgen/AR signaling suppressed the gene and protein levels of AMH via repression of SOX9.

Conclusions

Our data show that the functional androgen/AR signaling to repress SOX9 and AMH expression is essential for Sertoli cell maturation. Impairment of androgen/AR signaling promotes SOX9-mediated AMH production, accounts for impairments of Sertoli cells in SCOS azoospermic patients.