Anti-Müllerian hormone and its receptors

The Nuclear Receptor COUP-TFII Regulates Amhr2 Gene Transcription via a GC-Rich Promoter Element in Mouse Leydig Cells

The nuclear receptor chicken ovalbumin upstream promoter–transcription factor type II (COUP-TFII)/NR2F2 is expressed in adult Leydig cells, and conditional deletion of the Coup-tfii/Nr2f2 gene impedes their differentiation. Steroid production is also reduced in COUP-TFII–depleted Leydig cells, supporting an additional role in steroidogenesis for this transcription factor. COUP-TFII action in Leydig cells remains to be fully characterized. In the present work, we report that COUP-TFII is an essential regulator of the gene encoding the anti-Müllerian hormone receptor type 2 (Amhr2), which participates in Leydig cell differentiation and steroidogenesis. We found that Amhr2 mRNA levels are reduced in COUP-TFII–depleted MA-10 Leydig cells. Consistent with this, COUP-TFII directly activates a −1486 bp fragment of the mouse Amhr2 promoter in transient transfection assays. The COUP-TFII responsive region was localized between −67 and −34 bp. Chromatin immunoprecipitation assay confirmed COUP-TFII recruitment to the proximal Amhr2 promoter whereas DNA precipitation assay revealed that COUP-TFII associates with the −67/−34 bp region in vitro. Even though the −67/−34 bp region contains an imperfect nuclear receptor element, COUP-TFII–mediated activation of the Amhr2 promoter requires a GC-rich sequence at −39 bp known to bind the specificity protein (SP)1 transcription factor. COUP-TFII transcriptionally cooperates with SP1 on the Amhr2 promoter. Mutations that altered the GCGGGGCGG sequence at −39 bp abolished COUP-TFII–mediated activation, COUP-TFII/SP1 cooperation, and reduced COUP-TFII binding to the proximal Amhr2 promoter. Our data provide a better understanding of the mechanism of COUP-TFII action in Leydig cells through the identification and regulation of the Amhr2 promoter as a novel target.

Mismatches between the genetic and phenotypic sex in the wild Kou population of Nile tilapia Oreochromis niloticus

Sex determination and sex chromosomes can be very diverse between teleost species. The group of tilapias shows a polymorphism in sex determination not only between closely related species but also between domestic strains within a species. In the Nile tilapia, the major effect genes and therefore the Y chromosome have been located on either linkage group 1 (LG1) or LG23 depending on the strains. In a Japanese strain, the sex determinant of LG23 (the amhY gene) has been identified as a duplicated amh (anti-Müllerian hormone) gene, with its gametolog found on the X chromosome (amhX). AmhY is located in tandem with the amhΔY gene (a truncated form) on the Y chromosome. X and Y chromosome markers based on the amh genes have been validated only on a few domestic strains but not in wild populations. Here, we used four of these markers in order to examine (1) the possible variation in sex determination of a wild population of Nile tilapia living in Lake Kou (Burkina Faso), (2) putative polymorphisms for these amh copies and (3) the existence of sex reversed individuals in the wild. Our genotyping of 91 wild Kou individuals with the amh sex-diagnostic markers of LG23 showed that while phenotypic females were all XX, phenotypic males were either XY or XX. Progeny testing of eight of these XX males revealed that one of these males consistently sired all-female progenies, suggesting that it is a wild sex reversed male (which could result from high temperature effects). The other XX males gave balanced sex ratios, suggesting that sex is controlled by another locus (possibly on another LG) which may be epistatically dominant over the LG23 locus. Finally, identification of unexpected amh genotypes was found for two individuals. They produced either balanced or female-biased sex ratios, depending on the breeder with whom they were crossed, suggesting possible recombination between the X and the Y chromosomes.

Conservation and diversity in expression of candidate genes regulating socially-induced female-male sex change in wrasses

Fishes exhibit remarkably diverse, and plastic, patterns of sexual development, most striking of which is sequential hermaphroditism, where individuals readily reverse sex in adulthood. How this stunning example of phenotypic plasticity is controlled at a genetic level remains poorly understood. Several genes have been implicated in regulating sex change, yet the degree to which a conserved genetic machinery orchestrates this process has not yet been addressed. Using captive and in-the-field social manipulations to initiate sex change, combined with a comparative qPCR approach, we compared expression patterns of four candidate regulatory genes among three species of wrasses (Labridae)-a large and diverse teleost family where female-to-male sex change is pervasive, socially-cued, and likely ancestral. Expression in brain and gonadal tissues were compared among the iconic tropical bluehead wrasse (Thalassoma bifasciatum) and the temperate spotty (Notolabrus celidotus) and kyusen (Parajulus poecilepterus) wrasses. In all three species, gonadal sex change was preceded by downregulation of cyp19a1a (encoding gonadal aromatase that converts androgens to oestrogens) and accompanied by upregulation of amh (encoding anti-müllerian hormone that primarily regulates male germ cell development), and these genes may act concurrently to orchestrate ovary-testis transformation. In the brain, our data argue against a role for brain aromatase (cyp19a1b) in initiating behavioural sex change, as its expression trailed behavioural changes. However, we find that isotocin (it, that regulates teleost socio-sexual behaviours) expression correlated with dominant male-specific behaviours in the bluehead wrasse, suggesting it upregulation mediates the rapid behavioural sex change characteristic of blueheads and other tropical wrasses. However, it expression was not sex-biased in temperate spotty and kyusen wrasses, where sex change is more protracted and social groups may be less tightly-structured. Together, these findings suggest that while key components of the molecular machinery controlling gonadal sex change are phylogenetically conserved among wrasses, neural pathways governing behavioural sex change may be more variable.

Implications and Future Perspectives of AGEs in PCOS Pathophysiology

Human, animal, and in vitro studies provide evidence that advanced glycation end-products (AGEs) may contribute to the pathogenesis of polycystic ovary syndrome (PCOS) and its metabolic and reproductive consequences. AGEs are able to induce, via activation of key intracellular signaling pathways, the generation of oxidative stress and proinflammatory cytokines, thus contributing to the adverse health impact of PCOS. This review presents the implications of AGEs in several disease pathophysiologies, including PCOS, as well as the cellular and systemic effects of AGEs on insulin resistance (IR), hyperandrogenemia, endoplasmic reticulum (ER) stress, hypoxia, and ovarian function. The gaps in our knowledge will serve as launching pad for future developments ranging from dietary and lifestyle changes to pharmaceutical interventions aiming at potential applications in women with PCOS.

Crosstalk between advanced glycation end products and vitamin D: A compelling paradigm for the treatment of ovarian dysfunction in PCOS

Women with PCOS have elevated levels of the harmful advanced glycation end products (AGEs) and low serum levels of vitamin D. AGEs and their receptors may contribute to the pathogenesis of PCOS and its metabolic and reproductive consequences. On the other hand, vitamin D might improve PCOS phenotype and could alleviate the detrimental effects of AGEs. A literature review using PubMed was performed. Critical analysis was carried out for articles pertaining to: 1) the role of AGEs and their receptors in the pathophysiology of PCOS, in particular ovarian dysfunction, and 2) the action of vitamin D in attenuating the adverse effects of AGEs in women with PCOS at both the serum and the cellular levels. Data from in vitro experiments, animal models, and human studies provide compelling evidence that AGEs and their receptors may contribute to the pathogenesis of ovarian dysfunction in PCOS. The actions of AGEs in PCOS might be attenuated and/or reversed by the presence or supplementation of vitamin D. Once a mechanistic understanding of the relationship between AGEs and vitamin D is established, this knowledge might contribute to the subsequent development of new-targeted pharmacological therapies for improving ovarian health in women with PCOS.

Vitamin D attenuates the effect of advanced glycation end products on anti-Mullerian hormone signaling

Vitamin D3 (1,25-dihydroxyvitamin D3, VD3) in vitro attenuates the effect of the pro-inflammatory advanced glycation end products (AGEs) on steroidogenesis in human granulosa cells (GCs) by downregulating the receptor for AGEs (RAGE). It has been shown that VD3 alone downregulates anti-Mullerian hormone (AMH) type 2 receptor (AMHR-2) gene expression and suppresses AMH-induced SMAD 1/5/8 phosphorylation in granulosa cells. However, the effect of AGEs, in the absence or presence of VD3, on AMH action in GCs has not been studied. Using human GCs, this study showed that human glycated albumin (HGA), an in vitro representative for AGEs, upregulated AMHR-2 mRNA but did not alter AMH mRNA expression levels. VD3 inhibited the HGA-induced increase in AMHR-2 mRNA expression levels. In KGN granulosa cell line, recombinant AMH induced SMAD 1/5/8 phosphorylation. HGA augmented the recombinant AMH-induced SMAD 1/5/8 phosphorylation while the addition of VD3 to HGA attenuated the recombinant AMH-induced SMAD 1/5/8 phosphorylation. Thus, AGEs could potentially affect folliculogenesis as reflected by changes in AMH signaling. These findings have significant implications for women with polycystic ovary syndrome who have significantly elevated serum and ovarian AGEs.

Intersex, Hermaphroditism, and Gonadal Plasticity in Vertebrates: Evolution of the Müllerian Duct and Amh/Amhr2 Signaling

In vertebrates, sex organs are generally specialized to perform a male or female reproductive role. Acquisition of the Müllerian duct, which gives rise to the oviduct, together with emergence of the Amh/Amhr2 system favored evolution of viviparity in jawed vertebrates. Species with high sex-specific reproductive adaptations have less potential to sex reverse, making intersex a nonfunctional condition. Teleosts, the only vertebrate group in which hermaphroditism evolved as a natural reproductive strategy, lost the Müllerian duct during evolution. They developed for gamete release complete independence from the urinary system, creating optimal anatomic and developmental preconditions for physiological sex change. The common and probably ancestral role of Amh is related to survival and proliferation of germ cells in early and adult gonads of both sexes rather than induction of Müllerian duct regression. The relationship between germ cell maintenance and sex differentiation is most evident in species in which Amh became the master male sex-determining gene.

A Dense Linkage Map of Lake Victoria Cichlids Improved the Pundamilia Genome Assembly and Revealed a Major QTL for Sex-Determination

Genetic linkage maps are essential for comparative genomics, high quality genome sequence assembly and fine scale quantitative trait locus (QTL) mapping. In the present study we identified and genotyped markers via restriction-site associated DNA (RAD) sequencing and constructed a genetic linkage map based on 1,597 SNP markers of an interspecific F2 cross of two closely related Lake Victoria cichlids (Pundamilia pundamilia and P sp. 'red head'). The SNP markers were distributed on 22 linkage groups and the total map size was 1,594 cM with an average marker distance of 1.01 cM. This high-resolution genetic linkage map was used to anchor the scaffolds of the Pundamilia genome and estimate recombination rates along the genome. Via QTL mapping we identified a major QTL for sex in a ∼1.9 Mb region on Pun-LG10, which is homologous to Oreochromis niloticus LG 23 (Ore-LG23) and includes a well-known vertebrate sex-determination gene (amh).

Primary Immunoprevention of Epithelial Ovarian Carcinoma by Vaccination against the Extracellular Domain of Anti-Müllerian Hormone Receptor II

Epithelial ovarian carcinoma (EOC) is the most prevalent form of ovarian cancer in the United States, representing approximately 85% of all cases and causing more deaths than any other gynecologic malignancy. We propose that optimized control of EOC requires the incorporation of a vaccine capable of inducing safe and effective preemptive immunity in cancer-free women. In addition, we hypothesize that ovarian-specific self-proteins that are "retired" from autoimmune-inducing expression levels as ovaries age but are expressed at high levels in emerging EOC may serve as vaccine targets for mediating safe and effective primary immunoprevention. Here, we show that expression of the extracellular domain of anti-Müllerian hormone receptor II (AMHR2-ED) in normal tissues is confined exclusively to the human ovary, drops to nonautoimmune inducing levels in postmenopausal ovaries, and is at high levels in approximately 90% of human EOC. We found that AMHR2-ED vaccination significantly inhibits growth of murine EOC and enhances overall survival without inducing oophoritis in aged female mice. The observed inhibition of EOC growth was mediated substantially by induction of AMHR2-ED-specific IgG antibodies that agonize receptor signaling of a Bax/caspase-3-dependent proapoptotic cascade. Our results indicate that AMHR2-ED vaccination may be particularly useful in providing safe and effective preemptive immunity against EOC in women at high genetic or familial risk who have the greatest need for a preventive vaccine and ultimately in cancer-free postmenopausal women who account for 75% of all EOC cases. Cancer Prev Res; 10(11); 612-24. ©2017 AACRSee related editorial by Shoemaker et al., p. 607.

Identification and Evolution of TGF-β Signaling Pathway Members in Twenty-Four Animal Species and Expression in Tilapia

Transforming growth factor β (TGF-β) signaling controls diverse cellular processes during embryogenesis as well as in mature tissues of multicellular animals. Here we carried out a comprehensive analysis of TGF-β pathway members in 24 representative animal species. The appearance of the TGF-β pathway was intrinsically linked to the emergence of metazoan. The total number of TGF-β ligands, receptors, and smads changed slightly in all invertebrates and jawless vertebrates analyzed. In contrast, expansion of the pathway members, especially ligands, was observed in jawed vertebrates most likely due to the second round of whole genome duplication (2R) and additional rounds in teleosts. Duplications of TGFB2, TGFBR2, ACVR1, SMAD4 and SMAD6, which were resulted from 2R, were first isolated. Type II receptors may be originated from the ACVR2-like ancestor. Interestingly, AMHR2 was not identified in Chimaeriformes and Cypriniformes even though they had the ligand AMH. Based on transcriptome data, TGF-β ligands exhibited a tissue-specific expression especially in the heart and gonads. However, most receptors and smads were expressed in multiple tissues indicating they were shared by different ligands. Spatial and temporal expression profiles of 8 genes in gonads of different developmental stages provided a fundamental clue for understanding their important roles in sex determination and reproduction. Taken together, our findings provided a global insight into the phylogeny and expression patterns of the TGF-β pathway genes, and hence contribute to the greater understanding of their biological roles in the organism especially in teleosts.

Involvement of Bone Morphogenetic Proteins (BMP) in the Regulation of Ovarian Function

Primordial germ cells migrate to the fetal gonads and proliferate during gestation to generate a fixed complement of primordial follicles, the so-called ovarian reserve. Primordial follicles comprise an oocyte arrested at the diplotene stage of meiosis, surrounded by a layer of pregranulosa cells. Activation of primordial follicles to grow beyond this arrested stage is of particular interest because, once activated, they are subjected to regulatory mechanisms involved in growth, selection, maturation, and ultimately, ovulation or atresia. The vast majority of follicles succumb to atresia and are permanently lost from the quiescent or growing pool of follicles. The bone morphogenetic proteins (BMPs), together with other intraovarian growth factors, are intimately involved in regulation of follicle recruitment, dominant follicle selection, ovulation, and atresia. Activation of primordial follicles appears to be a continuous process, and the number of small antral follicles at the beginning of the menstrual cycle provides an indirect indication of ovarian reserve. Continued antral follicle development during the follicular phase of the menstrual cycle is driven by follicle stimulating hormone (FSH) and luteinizing hormone (LH) in conjunction with many intraovarian growth factors and inhibitors interrelated in a complex web of regulatory balance. The BMP signaling system has a major intraovarian role in many species, including the human, in the generation of transcription factors that influence proliferation, steroidogenesis, cell differentiation, and maturation prior to ovulation, as well as formation of corpora lutea after ovulation. At the anterior pituitary level, BMPs also contribute to the regulation of gonadotrophin production.

Anti-Müllerian hormone and risk of ovarian cancer in nine cohorts

Animal and experimental data suggest that anti-Müllerian hormone (AMH) serves as a marker of ovarian reserve and inhibits the growth of ovarian tumors. However, few epidemiologic studies have examined the association between AMH and ovarian cancer risk. We conducted a nested case-control study of 302 ovarian cancer cases and 336 matched controls from nine cohorts. Prediagnostic blood samples of premenopausal women were assayed for AMH using a picoAMH enzyme-linked immunosorbent assay. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using multivariable-adjusted conditional logistic regression. AMH concentration was not associated with overall ovarian cancer risk. The multivariable-adjusted OR (95% CI), comparing the highest to the lowest quartile of AMH, was 0.99 (0.59-1.67) (Ptrend : 0.91). The association did not differ by age at blood draw or oral contraceptive use (all Pheterogeneity : ≥0.26). There also was no evidence for heterogeneity of risk for tumors defined by histologic developmental pathway, stage, and grade, and by age at diagnosis and time between blood draw and diagnosis (all Pheterogeneity : ≥0.39). In conclusion, this analysis of mostly late premenopausal women from nine cohorts does not support the hypothesized inverse association between prediagnostic circulating levels of AMH and risk of ovarian cancer.

On the descent of the epididymo-testicular unit, cryptorchidism, and prevention of infertility

This comprehensive review provides in-depth coverage of progress made in understanding the molecular mechanisms underlying cryptorchidism, a frequent pathology first described in about 1786 by John Hunter. The first part focuses on the physiology, embryology, and histology of epididymo-testicular descent. In the last 20 years epididymo-testicular descent has become the victim of schematic drawings with an unjustified rejection of valid histological data. This part also includes discussion on the roles of gonadotropin-releasing hormone, fibroblast growth factors, Müllerian inhibiting substance, androgens, inhibin B, and insulin-like 3 in epididymo-testicular descent. The second part addresses the etiology and histology of cryptorchidism as well as the importance of mini-puberty for normal fertility development. A critical view is presented on current clinical guidelines that recommend early orchidopexy alone as the best possible treatment. Finally, by combining classical physiological information and the output of cutting-edge genomics data into a complete picture the importance of hormonal treatment in preventing cryptorchidism-induced infertility is underscored.

Gene editing nuclease and its application in tilapia

Gene editing nucleases including zinc-finger nucleases (ZFNs), transcription activator like effector nucleases (TALENs) and clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated (Cas) system (CRISPR/Cas9) provide powerful tools that improve our ability to understand the physiological processes and their underlying mechanisms. To date, these approaches have already been widely used to generate knockout and knockin models in a large number of species. Fishes comprise nearly half of extant vertebrate species and provide excellent models for studying many aspects of biology. In this review, we present an overview of recent advances in the use of gene editing nucleases for studies of fish species. We focus particularly on the use of TALENs and CRISPR/Cas9 genome editing for studying sex determination in tilapia.

Sex-Determining Mechanism in Avians

The sex of birds is determined by inheritance of sex chromosomes at fertilization. The embryo with two Z chromosomes (ZZ) develops into a male; by contrast, the embryo with Z and W chromosomes (ZW) becomes female. Two theories are hypothesized for the mechanisms of avian sex determination that explain how genes carried on sex chromosomes control gonadal differentiation and development during embryogenesis. One proposes that the dosage of genes on the Z chromosome determines the sexual differentiation of undifferentiated gonads, and the other proposes that W-linked genes dominantly determine ovary differentiation or inhibit testis differentiation. Z-linked DMRT1, which is a strong candidate avian sex-determining gene, supports the former hypothesis. Although no candidate W-linked gene has been identified, extensive evidence for spontaneous sex reversal in birds and aneuploid chimeric chickens with an abnormal sex chromosome constitution strongly supports the latter hypothesis. After the sex of gonad is determined by a gene(s) located on the sex chromosomes, gonadal differentiation is subsequently progressed by several genes. Developed gonads secrete sex hormones to masculinize or feminize the whole body of the embryo. In this section, the sex-determining mechanism as well as the genes and sex hormones mainly involved in gonadal differentiation and development of chicken are introduced.

Anti-Mullerian Hormone in Premenopausal Women and After Spontaneous or Surgically Induced Menopause

OBJECTIVE

The objectives of this study were: (1) to determine anti-Mullerian hormone (AMH) levels in menopausal women, and (2) to confirm the source of AMH in cycling women and its disappearance after the removal of the source.

METHODS

An observational and prospective study was conducted.

RESULTS

A total of 47 women were recruited for the study. The study population consisted of the following groups of patients: (A) women of late reproductive age (n = 24; mean age +/- SD, 44 +/- 2.8 years); (B) menopausal women (n =14; mean age, 56 +/- 4 years); and (C) regularly cycling women undergoing surgical menopause (n = 9; mean age, 43 +/- 4 years). Blood samples were obtained from all patients. In patients undergoing surgery, blood samples were obtained before and after surgery. AMH was undetectable in 13 of 14 postmenopausal women, whereas it was undetectable in only two of 24 women of late reproductive age. A significant negative correlation has been found between AMH and age or follicle-stimulating hormone (FSH) in women of late reproductive age. In women who were candidates for oophorectomy, samples were obtained 3-5 days after surgery. AMH was undetectable after the surgery in all women.

CONCLUSIONS

We found that AMH levels decreased in women in the late reproductive period and that menopause and ovariectomy in regularly cycling women are associated to undetectable AMH in serum. These observations confirm that the ovary could be the only source of AMH in women and that it is a novel marker for ovarian aging.

Anti-Müllerian hormone for prediction of ovarian response in Chinese infertile women undergoing IVF/ICSI cycles: a prospective, multi-centre, observational study

This study explored the correlation between serum anti-Müllerian hormone (AMH) concentration and the number of retrieved oocytes after ovarian stimulation in Chinese infertile women undergoing assisted reproductive technology treatment and AMH cut-off values predicting low and high ovarian response. This was a prospective, multi-centre, observational study. A total of 615 subjects were included in nine assisted reproductive centres in China for outcome analysis. Subjects received assisted reproductive technology treatment and used recombinant human FSH (r-HFSH) or r-HFSH plus recombinant LH (rLH) for ovarian stimulation according to conventional treatment regimens. The main outcome variables were correlations between AMH and the number of retrieved oocytes and the cut-off values of AMH predicting low and high ovarian response. Serum AMH concentration was positively correlated with the number of oocytes retrieved in Chinese infertile women treated with IVF/intracytoplasmic sperm injection (ICSI) (Pearson correlation coefficient = 0.4754, P < 0.0001). The optimal AMH cut-off value was 2.6 ng/ml (sensitivity: 81.28%, specificity: 59.51%) in predicting high and normal response, and 1.1 ng/ml (sensitivity: 52.27%, specificity: 87.23%) in predicting low and normal response. In conclusion, serum AMH concentration can be used as a biomarker to predict ovarian response in Chinese infertile women treated with assisted reproductive technology.

Undescended testis - current trends and guidelines: a review of the literature

The best mode of undescended testis (UDT) treatment remains controversial. However, knowledge gained from randomized controlled studies and meta-analyses allowed different groups of researchers to set out guidelines on management of patients with UDT. The authors reviewed recent literature and came to the following conclusions: (1) Hormonal treatment is not recommended, considering both the immediate results (only 15-20% of retained testes descend) and the possible long-term adverse effects on spermatogenesis. (2) Surgery is the treatment of choice; orchiopexy is successful in about 95% of UDT, with a low rate of complications (about 1%). (3) Orchiopexy should be performed between 12 and 18 months of age, or at first contact if diagnosed later.

The role of AMH in the pathophysiology of polycystic ovarian syndrome

Polycystic ovarian syndrome (PCOS) affects 5 - 10% of reproductive age women, but its pathogenesis is still poorly understood. The aim of this review is to collate evidence and summarize our current knowledge of the role of anti-Müllerian hormone (AMH) in PCOS pathogenesis. AMH is increased and correlated with the various reproductive and metabolic/endocrine alterations in PCOS. AMH plays an inhibitory role in follicular development and recruitment, contributing to follicular arrest. AMH inhibitory action on FSH-induced aromatase production likely contributes to hyperandrogenism in PCOS, which further enhances insulin resistance in these women. Elevated serum AMH concentrations are predictive of poor response to various treatments of PCOS including weight loss, ovulation induction and laparoscopic ovarian drilling, while improvement in various clinical parameters following treatment is associated with serum AMH decline, further supporting an important role for AMH in the pathophysiology of this syndrome. This review emphasizes the need for understanding the exact mechanism of action of AMH in the pathophysiology of PCOS. This may lead to the development of new treatment modalities targeting AMH to treat PCOS, as well as help clinicians in prognostication and better tailoring existing treatments for this disease.

Overexpression of Anti-Müllerian Hormone Disrupts Gonadal Sex Differentiation, Blocks Sex Hormone Synthesis, and Supports Cell Autonomous Sex Development in the Chicken

The primary role of Anti-Müllerian hormone (AMH) during mammalian development is the regression of Müllerian ducts in males. This highly conserved function is retained in birds and is supported by the high levels of AMH expression in developing testes. Mammalian AMH expression is regulated by a combination of transcription factors, the most important being Sry-type high-mobility-group box transcription factor-9 (SOX9). In the chicken embryo, however, AMH mRNA expression precedes that of SOX9, leading to the view that AMH may play a more central role in avian testicular development. To define its role in chicken gonadal development, AMH was overexpressed using the RCASBP viral vector. AMH caused the gonads of both sexes to develop as small and undeveloped structures at both embryonic and adult stages. Molecular analysis revealed that although female gonads developed testis-like cords, gonads lacked Sertoli cells and were incapable of steroidogenesis. A similar gonadal phenotype was also observed in males, with a complete loss of both Sertoli cells, disrupted SOX9 expression and gonadal steroidogenesis. At sexual maturity both sexes showed a female external phenotype but retained sexually dimorphic body weights that matched their genetic sexes. These data suggest that AMH does not operate as an early testis activator in the chicken but can affect downstream events, such as sex steroid hormone production. In addition, this study provides a unique opportunity to assess chicken sexual development in an environment of sex hormone deficiency, demonstrating the importance of both hormonal signaling and direct cell autonomous factors for somatic sex identity in birds.

Inhibitors of c-Jun phosphorylation impede ovine primordial follicle activation

STUDY HYPOTHESIS

Is the c-Jun-N-terminal kinase (JNK) pathway implicated in primordial follicle activation?

STUDY FINDING

Culture of ovine ovarian cortex in the presence of two different c-Jun phosphorylation inhibitors impeded pre-antral follicle activation.

WHAT IS KNOWN ALREADY

Despite its importance for fertility preservation therapies, the mechanisms of primordial follicle activation are poorly understood. Amongst different signalling pathways potentially involved, the JNK pathway has been previously shown to be essential for cell cycle progression and pre-antral follicle development in mice.

STUDY DESIGN, SAMPLES/MATERIALS, METHODS

Ovine ovarian cortex pieces were cultured with varying concentrations of SP600125, JNK inhibitor VIII or anti-Mullerian hormone (AMH) in the presence of FSH for 9 days. Follicular morphometry and immunohistochemistry for proliferating cell nuclear antigen (PCNA), apoptosis and follicle activation (Foxo3a) were assessed.

MAIN RESULTS AND THE ROLE OF CHANCE

Inhibition of primordial follicle activation occurred in the presence of SP600125, JNK inhibitor VIII and AMH when compared with controls (all P < 0.05) after 2 days of culture. However, only in the highest concentrations used was the inhibition of activation associated with induction of follicular apoptosis (P < 0.05). In growing follicles, PCNA antigen expression was reduced when the JNK inhibitors or AMH were used (P < 0.05 versus control), indicating reduced proliferation of the somatic compartment.

LIMITATIONS, REASONS FOR CAUTION

Although we evaluated the effects of inhibition of c-Jun phosphorylation on primordial follicle development, we did not determine the cellular targets and mechanism of action of the inhibitors.

WIDER IMPLICATIONS OF THE FINDINGS

These results are the first to implicate the JNK pathway in primordial follicle activation and could have significant consequences for the successful development of fertility preservation strategies and our understanding of primordial follicle activation.

LARGE SCALE DATA

n/a.

STUDY FUNDING AND COMPETING INTERESTS

Dr Michael J. Bertoldo and the laboratories involved in the present study were supported by a grant from 'Région Centre' (CRYOVAIRE, Grant number #320000268). There are no conflicts of interest to declare.

Structural insights into BMP receptors: Specificity, activation and inhibition

Bone morphogenetic proteins (BMPs) are members of the transforming growth factor-β family (TGFβ), which signal through hetero-tetrameric complexes of type I and type II receptors. In humans there are many more TGFβ ligands than receptors, leading to the question of how particular ligands can initiate specific signaling responses. Here we review structural features of the ligands and receptors that contribute to this specificity. Ligand activity is determined by receptor-ligand interactions, growth factor prodomains, extracellular modulator proteins, receptor assembly and phosphorylation of intracellular signaling proteins, including Smad transcription factors. Detailed knowledge about the receptors has enabled the development of BMP-specific type I receptor kinase inhibitors. In future these may help to treat human diseases such as fibrodysplasia ossificans progressiva.

A Tandem Duplicate of Anti-Müllerian Hormone with a Missense SNP on the Y Chromosome Is Essential for Male Sex Determination in Nile Tilapia, Oreochromis niloticus

Variation in the TGF-β signaling pathway is emerging as an important mechanism by which gonadal sex determination is controlled in teleosts. Here we show that amhy, a Y-specific duplicate of the anti-Müllerian hormone (amh) gene, induces male sex determination in Nile tilapia. amhy is a tandem duplicate located immediately downstream of amhΔ-y on the Y chromosome. The coding sequence of amhy was identical to the X-linked amh (amh) except a missense SNP (C/T) which changes an amino acid (Ser/Leu92) in the N-terminal region. amhy lacks 5608 bp of promoter sequence that is found in the X-linked amh homolog. The amhΔ-y contains several insertions and deletions in the promoter region, and even a 5 bp insertion in exonVI that results in a premature stop codon and thus a truncated protein product lacking the TGF-β binding domain. Both amhy and amhΔ-y expression is restricted to XY gonads from 5 days after hatching (dah) onwards. CRISPR/Cas9 knockout of amhy in XY fish resulted in male to female sex reversal, while mutation of amhΔ-y alone could not. In contrast, overexpression of Amhy in XX fish, using a fosmid transgene that carries the amhy/amhΔ-y haplotype or a vector containing amhy ORF under the control of CMV promoter, resulted in female to male sex reversal, while overexpression of AmhΔ-y alone in XX fish could not. Knockout of the anti-Müllerian hormone receptor type II (amhrII) in XY fish also resulted in 100% complete male to female sex reversal. Taken together, these results strongly suggest that the duplicated amhy with a missense SNP is the candidate sex determining gene and amhy/amhrII signal is essential for male sex determination in Nile tilapia. These findings highlight the conserved roles of TGF-β signaling pathway in fish sex determination.

Unlike mammals, the identity of the master sex-determining gene varies among fish species, and it is not yet clear if there is a common molecular pathway regulating gonadal sex determination across teleosts. Here we show that a Y-linked duplicate of the anti-Mullerian hormone (amhy) is essential for male sex determination in tilapia. Mutation of amhy resulted in male to female sex reversal, while overexpression of it resulted in female to male sex reversal. A missense single nucleotide polymorphisms (SNP) (C/T) in the open reading frame (ORF) of amhy might contribute to male sex determination in tilapia. Knockout of the anti-Müllerian hormone receptor type II (amhrII) also resulted in male to female sex reversal. Taken the amhy in Patagonian pejerrey, amhrII in Takifugu rubripes, gsdf^Y in Oryzias luzonensis into consideration, these data highlight an important role for TGF-β signaling in teleost sex determination.

Regulation of Murine Ovarian Epithelial Carcinoma by Vaccination against the Cytoplasmic Domain of Anti-Müllerian Hormone Receptor II

Anti-Müllerian hormone receptor, type II (AMHR2), is a differentiation protein expressed in 90% of primary epithelial ovarian carcinomas (EOCs), the most deadly gynecologic malignancy. We propose that AMHR2 may serve as a useful target for vaccination against EOC. To this end, we generated the recombinant 399-amino acid cytoplasmic domain of mouse AMHR2 (AMHR2-CD) and tested its efficacy as a vaccine target in inhibiting growth of the ID8 transplantable EOC cell line in C57BL/6 mice and in preventing growth of autochthonous EOCs that occur spontaneously in transgenic mice. We found that AMHR2-CD immunization of C57BL/6 females induced a prominent antigen-specific proinflammatory CD4+ T cell response that resulted in a mild transient autoimmune oophoritis that resolved rapidly with no detectable lingering adverse effects on ovarian function. AMHR2-CD vaccination significantly inhibited ID8 tumor growth when administered either prophylactically or therapeutically, and protection against EOC growth was passively transferred into naive recipients with AMHR2-CD-primed CD4+ T cells but not with primed B cells. In addition, prophylactic AMHR2-CD vaccination of TgMISIIR-TAg transgenic mice significantly inhibited growth of autochthonous EOCs and provided a 41.7% increase in mean overall survival. We conclude that AMHR2-CD vaccination provides effective immunotherapy of EOC with relatively benign autoimmune complications.

Anti-Müllerian Hormone Is Required for Chicken Embryonic Urogenital System Growth but Not Sexual Differentiation

In mammals, the primary role of anti-Müllerian hormone (AMH) during development is the regression of Müllerian ducts in males. These structures otherwise develop into fallopian tubes, oviducts, and upper vagina, as in females. This highly conserved function is retained in birds and is supported by the high levels of AMH expression in developing testes. In mammals, AMH expression is controlled partly by the transcription factor, SOX9. However, in the chicken, AMH mRNA expression precedes that of SOX9 , leading to the view that AMH may lie upstream of SOX9 and play a more central role in avian testicular development. To help define the role of AMH in chicken gonad development, we suppressed AMH expression in chicken embryos using RNA interference. In males, AMH knockdown did not affect the expression of key testis pathway genes, and testis cords developed normally. However, a reduction in the size of the mesonephros and gonads was observed, a phenotype that was evident in both sexes. This growth defect occurred as a result of the reduced proliferative capacity of the cells of these tissues, and male gonads also had a significant reduction in germ cell numbers. These data suggest that although AMH does not directly contribute to testicular or ovarian differentiation, it is required in a sex-independent manner for proper cell proliferation and urogenital system growth.

A Mouse Model That Reproduces the Developmental Pathways and Site Specificity of the Cancers Associated With the Human BRCA1 Mutation Carrier State

Predisposition to breast and extrauterine Müllerian carcinomas in BRCA1 mutation carriers is due to a combination of cell-autonomous consequences of BRCA1 inactivation on cell cycle homeostasis superimposed on cell-nonautonomous hormonal factors magnified by the effects of BRCA1 mutations on hormonal changes associated with the menstrual cycle. We used the Müllerian inhibiting substance type 2 receptor (Mis2r) promoter and a truncated form of the Follicle stimulating hormone receptor (Fshr) promoter to introduce conditional knockouts of Brca1 and p53 not only in mouse mammary and Müllerian epithelia, but also in organs that control the estrous cycle. Sixty percent of the double mutant mice developed invasive Müllerian and mammary carcinomas. Mice carrying heterozygous mutations in Brca1 and p53 also developed invasive tumors, albeit at a lesser (30%) rate, in which the wild type alleles were no longer present due to loss of heterozygosity. While mice carrying heterozygous mutations in both genes developed mammary tumors, none of the mice carrying only a heterozygous p53 mutation developed such tumors (P < 0.0001), attesting to a role for Brca1 mutations in tumor development. This mouse model is attractive to investigate cell-nonautonomous mechanisms associated with cancer predisposition in BRCA1 mutation carriers and to investigate the merit of chemo-preventive drugs targeting such mechanisms.

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Mouse model reproducing both, cell-autonomous and cell-nonautonomous mechanisms of cancer risk in BRCA1 mutation carriers.

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The Müllerian and mesonephric ducts are embryologically linked, possibly accounting for Müllerian clear cell carcinomas.

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Foci of endosalpingiosis are at increased risk of cancer in the absence of a functional Brca1.

Most individuals with familial predisposition to breast and ovarian cancer carry germline mutations in BRCA1. Cancer predisposition in such carriers is due not only to effects of these mutations in tissues with an elevated cancer risk, but also in organs that control the menstrual cycle, which influences such tissues. The animal model that we developed mimics both mechanisms, which will facilitate our understanding of the contribution of menstrual cycle regulation to risk of these cancers. Our characterization of this model also led to insights into the origin of the serous and clear cell subtypes of ovarian cancer.

Anti-Müllerian hormone: a potentially useful biomarker for the diagnosis of canine Sertoli cell tumours

Background

Testicular tumours are common in dogs and in many cases do not give rise to clinical signs. In other cases, signs of feminization, hyperpigmentation or alopecia may be observed, most commonly associated with Sertoli cell tumours (SCT). Although these signs are often associated with elevated concentrations of oestradiol, analysis of oestradiol may give inconclusive results due to large variations among individuals. Other biomarkers are therefore needed. Anti-Müllerian hormone (AMH) is expressed by the Sertoli cell. In humans, AMH has been shown to be a specific marker of Sertoli cell origin in gonadal tumours. Using immunohistochemistry, AMH has been shown to be a useful marker of immature and neoplastic Sertoli cells in dogs. The aim of the present study was to evaluate the clinical relevance of AMH analysis in peripheral blood in the diagnostic workup of dogs with suspected testicular tumours.

Results

Blood was collected from 20 dogs with a palpable testicular mass and from 27 healthy controls. Serum was analysed for oestradiol-17β using a RIA and for AMH using an ELISA. The Mann–Whitney U test was used to compare hormone concentrations between different groups.

All control dogs had AMH concentrations ≤ 10 ng/mL, except one outlier that had a concentration of 43 ng/mL. Six dogs with SCT or mixed tumours containing SCT had AMH concentrations higher than 22 ng/mL, significantly higher than AMH concentrations in control dogs (P = 0.0004). Concentrations between 10 and 22 ng/mL were found in about half of the dogs with non-neoplastic testicular pathologies or with testicular tumours other than SCTs. Age did not significantly affect concentrations of AMH in the control dogs.

Conclusion

AMH was shown to be a promising biomarker for the diagnosis of Sertoli cell tumours in dogs.

Mechanisms of BMP-Receptor Interaction and Activation

Bone morphogenetic proteins (BMPs), together with the eponymous transforming growth factor (TGF) β and the Activins form the TGFβ superfamily of ligands. This protein family comprises more than 30 structurally highly related proteins, which determine formation, maintenance, and regeneration of tissues and organs. Their importance for the development of multicellular organisms is evident from their existence in all vertebrates as well as nonvertebrate animals. From their highly specific functions in vivo either a strict relation between a particular ligand and its cognate cellular receptor and/or a stringent regulation to define a distinct temperospatial expression pattern for the various ligands and receptor is expected. However, only a limited number of receptors are found to serve a large number of ligands thus implicating highly promiscuous ligand-receptor interactions instead. Since in tissues a multitude of ligands are often found, which signal via a highly overlapping set of receptors, this raises the question how such promiscuous interactions between different ligands and their receptors can generate concerted and highly specific cellular signals required during embryonic development and tissue homeostasis.

Single nucleotide polymorphisms in the Anti-Müllerian hormone (AMH Ile(49)Ser) and Anti-Müllerian hormone type II receptor (AMHRII -482 A>G) as genetic markers in assisted reproduction technology

PURPOSE

The aim of the study was to evaluate whether the presence Antimullerian hormone (AMH) and Antimullerian hormone type II receptor (AMHRII) single nucleotide polymorphisms (SNPs) Ile(49)Ser and -482A>G respectively are related to the assisted reproduction outcome.

METHODS

A prospective cross-sectional observational study was conducted in order to assess the distribution of AMH and AMHRII SNPs in two cohorts, one of healthy women (N = 100) and the control group and the IVF/ICSI group (N = 151) consisted of women undergoing IVF/ICSI treatment for infertility. Furthermore, a prospective longitudinal observational study was performed on the latter group to assess possible associations of these SNPs with patients' characteristics and controlled ovarian stimulation (COS) and pregnancy outcome.

RESULTS

Among non-carriers of the AMH (Ile(49)Ser) polymorphism, basal FSH levels were lower in those with more than two of previous IVF attempts and fertilization rate was statistically higher in those with peak serum E2 levels below 1500 pg/ml, whereas among non-carriers of the AMHRII (-482 A>G) polymorphism, number of follicles was higher in those with more than two previous IVF attempts and total dose of gonadotropins was lower in those with peak serum E2 levels above 1500 pg/ml.

CONCLUSIONS

There was evidence that in specific subgroups of women undergoing IVF/ICSI, AMH and AMHRII SNPs may be related to patients' characteristics and controlled ovarian stimulation and pregnancy outcome and thus may provide a means for the prediction of ovarian response in specific subgroups of women entering an IVF/ICSI program.

Genetics of sexual development: an evolutionary playground for fish

Teleost fishes are the most species-rich clade of vertebrates and feature an overwhelming diversity of sex-determining mechanisms, classically grouped into environmental and genetic systems. Here, we review the recent findings in the field of sex determination in fish. In the past few years, several new master regulators of sex determination and other factors involved in sexual development have been discovered in teleosts. These data point toward a greater genetic plasticity in generating the male and female sex than previously appreciated and implicate novel gene pathways in the initial regulation of the sexual fate. Overall, it seems that sex determination in fish does not resort to a single genetic cascade but is rather regulated along a continuum of environmental and heritable factors.

[What's new in 2014 about anti-Müllerian hormone?]

The existence of the anti-Müllerian hormone (AMH) has been postulated by Professor Alfred Jost to explain the regression of the Müllerian ducts during male sexual differentiation. Since then, AMH has been purified, its gene and specific receptor, AMHR-II have been cloned. Further, the signaling pathways were identified and it has been observed that AMH was produced by the granulosa cells of growing follicles. From the 2000s, unexpected roles of AMH have been highlighted, reactivating international research on this hormone. It is now well established that AMH plays a key role in the follicular recruitment and development. Over the past years, serum AMH measurements have been proposed as a marker of the follicular ovarian status, and a predictor of assisted reproductive cycles. AMH is also useful to assess the effectiveness of treatment of some gynecological tumors. This article is a review of the past five years advances on the regulation of the expression of AMH and its specific receptor AMHR-II in female.

Molecular players involved in temperature-dependent sex determination and sex differentiation in Teleost fish

The molecular mechanisms that underlie sex determination and differentiation are conserved and diversified. In fish species, temperature-dependent sex determination and differentiation seem to be ubiquitous and molecular players involved in these mechanisms may be conserved. Although how the ambient temperature transduces signals to the undifferentiated gonads remains to be elucidated, the genes downstream in the sex differentiation pathway are shared between sex-determining mechanisms. In this paper, we review recent advances on the molecular players that participate in the sex determination and differentiation in fish species, by putting emphasis on temperature-dependent sex determination and differentiation, which include temperature-dependent sex determination and genetic sex determination plus temperature effects. Application of temperature-dependent sex differentiation in farmed fish and the consequences of temperature-induced sex reversal are discussed.

Temperature induced-masculinisation in the Nile tilapia causes rapid up-regulation of both dmrt1 and amh expressions

Nile tilapia has primarily a XX/XY sex determining system but minor genetic factors as well as temperature can override the major factors. Female XX progenies can be sex-reversed into functional males by rearing at high temperatures (>34°C) from 10dpf onwards. Temperature effects on the molecular pathways during sex differentiation in teleosts need to be deciphered. The temporal expression profiles of cyp19a1a and foxl2, two ovarian-developmental genes and dmrt1 and amh, two testes-developmental genes were analysed during key stages of the sex differentiation of genetic all-females, all-males and temperature-masculinised XX females (TM) tilapia. Overall QPCR analysis was similar between gonads and trunks. Both amh and dmrt1 expressions were up-regulated simultaneously in TM already at 13-15dpf. Dmrt1 expression became markedly elevated ∼3-fold higher than XY male levels at 20-26dpf whereas amh had similar levels to XY males. Foxl2 and cyp19a1a expression profiles were similar. Both were up-regulated at early stages in TM but repressed after 17-19dpf, whilest levels continued to increase in XX-females. Our results show that temperature action on tilapia testis development induces the rapid increase of both dmrt1 and amh expressions followed by the down-regulation of foxl2 and cyp19a1a. This suggests that dmrt1 and/or amh may be the modulator(s) of the down-regulation of foxl2 and/or cyp19a1a.

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.

Müllerian inhibiting substance in the caudate amphibian Pleurodeles waltl

Müllerian inhibiting substance (MIS, also known as anti-Müllerian hormone), is a key factor of male sex differentiation in vertebrates. In amniotes, it is responsible for Müllerian duct regression in male embryos. In fish, despite the absence of Müllerian ducts, MIS is produced and controls germ cell proliferation during gonad differentiation. Here we show for the first time the presence of MIS in an amphibian species, Pleurodeles waltl. This is very astonishing because in caudate amphibians, Müllerian ducts do not regress in males. Phylogenetic analysis of MIS P. waltl ortholog revealed that the deduced protein segregates with MIS from other vertebrates and is clearly separated from other TGF-β family members. In larvae, MIS mRNA was expressed at higher levels in the developing testes than in the ovaries. In the testis, MIS mRNA expression was located within the lobules that contain Sertoli cells. Besides, expression of MIS was modified in the case of sex reversal: it increased after masculinizing heat treatment and decreased after estradiol feminizing exposure. In addition to the data obtained recently in the fish medaka, our results suggest that the role of MIS on Müllerian ducts occurred secondarily during the course of evolution.

Follicular-fluid anti-Mullerian hormone (FF AMH) is a plausible biochemical indicator of functional viability of oocyte in conventional in vitro fertilization (IVF) cycles

CONTEXT

Oocyte quality may be a governing factor in influencing in vitro fertilization (IVF) outcomes. However, morphological evaluation of oocyte quality is difficult in conventional IVF cycles. Follicular-fluid (FF), the site for oocyte growth and development, has not yet been sufficiently explored to obtain a marker indicative of oocyte quality. Anti-Mullerian hormone (AMH) is produced by granulosa cells of preantral and early-antral follicles and is released in FF.

AIM

To investigate AMH as a biochemical indicator of functional viability/quality of oocyte produced in the FF micro-environmental milieu.

SETTINGS AND DESIGN

Prospective study involving 132 cycles of conventional IVF-embryo transfer (ET) in infertile women.

SUBJECTS AND METHODS

AMH concentration was estimated in pooled FF on day of oocyte pickup. Cycles were sorted into low and high groups according to median (50 (th) centile) values of measurement. Main outcome measure was oocyte viability, which included morphological assessment of oocyte quality, fertilization rate, clinical pregnancy, and implantation rates.

STATISTICAL ANALYSIS

Graph-pad Prism 5 statistical package.

RESULTS

Low FF AMH group shows significantly higher percentage of top-quality oocytes (65.08 ± 24.88 vs. 50.18 ± 25.01%, P =0.0126), fertilization (83.65 ± 18.38 vs. 75.78 ± 21.02%, P =0.0171), clinical pregnancy (57.57 vs. 16.67%, P >0.0001), and embryo implantation rates (29.79 vs. 7.69%, P >0.0001) compared to high FF AMH group. FF AMH shares an inverse correlation with FF E2 (Pearson r = -0.43, r(2) = 0.18) and clinical pregnancy (Pearson r = -0.46, r(2) = 0.21). Threshold value of FF AMH for pregnancy is >1.750 ng/mg protein.

CONCLUSION

FF AMH is a plausible biochemical indicator of functional viability of oocyte in conventional IVF cycles.

The Wilms tumor gene, Wt1, is critical for mouse spermatogenesis via regulation of sertoli cell polarity and is associated with non-obstructive azoospermia in humans

Azoospermia is one of the major reproductive disorders which cause male infertility in humans; however, the etiology of this disease is largely unknown. In the present study, six missense mutations of WT1 gene were detected in 529 human patients with non-obstructive azoospermia (NOA), indicating a strong association between WT1 mutation and NOA. The Wilms tumor gene, Wt1, is specifically expressed in Sertoli cells (SCs) which support spermatogenesis. To examine the functions of this gene in spermatogenesis, Wt1 was deleted in adult testis using Wt1^flox and Cre-ER^TM mice strains. We found that inactivation of Wt1 resulted in massive germ cell death and only SCs were present in most of the seminiferous tubules which was very similar to NOA in humans. In investigating the potential mechanism for this, histological studies revealed that the blood–testis barrier (BTB) was disrupted in Wt1 deficient testes. In vitro studies demonstrated that Wt1 was essential for cell polarity maintenance in SCs. Further studies found that the expression of cell polarity associated genes (Par6b and E-cadherin) and Wnt signaling genes (Wnt4, Wnt11) were downregulated in Wt1 deficient SCs, and that the expression of Par6b and E-cadherin was regulated by Wnt4. Our findings suggest that Wt1 is important in spermatogenesis by regulating the polarity of SCs via Wnt signaling pathway and that WT1 mutation is one of the genetic causes of NOA in humans.

Infertility is one of the most common health problems, affecting about 15% of the couples in the world. In about half of these couples, infertility is related to male reproductive defect. Azoospermia is one of the major causes of male infertility in humans. Previous studies have found that the mutation or deletion of some genes is associated with azoospermia; however, the genetic cause of this remains largely unknown. In the present study, we detected Wt1 missense mutations in men with non-obstructive azoospermia (NOA). An essential function for WT1 in male spermatogenesis was confirmed by the use of a Wt1 conditional knockout mouse strain. Inactivation of Wt1 resulted in germ cell loss in mice, which was similar to NOA in human patients. Our data indicate that WT1 mutation is one genetic cause of male infertility and suggest that WT1 mutational analysis will be useful for diagnosis in a clinical setting.

Fusion-derived epithelial cancer cells express hematopoietic markers and contribute to stem cell and migratory phenotype in ovarian carcinoma

For a long time, the external milieu of cancer cells was considered to be of secondary importance when compared with its intrinsic properties. That has changed now as the microenvironment is considered to be a major contributing factor toward the progression of tumor. In this study, we show that in human and mouse epithelial ovarian carcinoma and mouse lung carcinoma, the interaction between tumor-infiltrating hematopoietic cells and epithelial cancer cells results in their fusion. Intriguingly, even after the fusion event, cancer cells retain the expression of the pan-hematopoietic marker (CD45) and various markers of hematopoietic lineage, including those of hematopoietic stem cells, indicating that the hematopoietic genome is not completely reprogrammed. This observation may have implications on the bone marrow contribution to the cancer stem cell population. Interestingly, it was seen that in both cancer models, the expression of chemokine receptor CXCR4 was largely contributed to by the fused compartment of cancer cells. We hypothesize that the superior migratory potential gained by the cancer cells due to the fusion helps in its dissemination to various secondary organs upon activation of the CXCR4/CXCL12 axis. We are the first to report the presence of a hemato-epithelial cancer compartment, which contributes to stem cell markers and CXCR4 in epithelial carcinoma. This finding has repercussions on CXCR4-based therapeutics and opens new avenues in discovering novel molecular targets against fusion and metastasis.

Establishment of adult mouse Sertoli cell lines by using the starvation method

Sertoli cells were isolated from the testes of 6-week-old mice and stable Sertoli cell lines with higher proliferation rates were subcloned after starvation of primary cultured cells. After two rounds of this subcloning, 33 subcloned lines were selected on the basis of their proliferation rates. In addition, these subclones were screened according to their phagocytic activity and the characteristics of mature Sertoli cells, such as the expression of androgen receptors (ARs) and progesterone receptors, by using western blotting and immunocytochemical analysis, in addition to their morphology and proliferation rates. After the third round of subcloning, 12 subclones were selected for the final selection using RT-PCR for identification of genes specifically expressed by various testicular cells. Three clones were selected that expressed Sertoli-cell-specific genes, i.e. stem cell factor, clusterin, AR, α-inhibin, transferrin, Wilms' tumour-1, Müllerian inhibitory substance, sex-determining region Y-box 9, FSH receptor (Fshr) and occludin; however, these clones did not express globulin transcription factor 1, steroidogenic factor or androgen-binding protein. These clones also expressed growth and differentiation factors that act on germ cells, such as leukaemia inhibitory factor, transforming growth factor β1 and basic fibroblast growth factor 2, but did not express c-kit (specific for germ cells), LH receptor and 3β-hydroxyl-dehydrogenase (specific for Leydig cells). Immunocytochemical data confirmed the expression of clusterin in these clones. Furthermore, the Bromodeoxyuridine incorporation assay confirmed the proliferation activity of these clones throughFshrafter treatment with FSH. These clones are considered to be valuable tools for the study of Sertoli cell-specific gene expression and function.

BMP system expression in GCs from polycystic ovary syndrome women and the in vitro effects of BMP4, BMP6, and BMP7 on GC steroidogenesis

BACKGROUND

The bone morphogenetic proteins (BMPs) are growth factors involved in the folliculogenesis. Alteration in their expression may compromise the reproductive process in disease such as the polycystic ovary syndrome (PCOS). This study investigated the expression and role of granulosa cell (GC) BMP from normal cycling and PCOS women.

METHODS AND RESULTS

This prospective study was performed in GCs obtained from 14 patients undergoing IVF: i) six women with normal ovulatory cycles and tubal or male infertility and ii) eight women with PCOS. BMP2, BMP4, BMP5, BMP6, BMP7, and BMP8A and their receptors BMPR1A, BMPR1B, and BMPR2 were identified by RT-PCR in GCs from normally cycling and PCOS women. BMP4, BMP6, and BMP7 expressions were confirmed by immunohistochemistry. Quantitative transcript analysis showed the predominant expression of BMP6. In GCs from PCOS women, an overexpression of BMP6 (P<0.01) and BMPR1A mRNA (P<0.05) was observed. GC culture experiments demonstrated that basal estradiol (E₂) production was threefold higher but FSH-induced E₂ increment was twofold lower in PCOS compared with controls. In PCOS, BMP6 and BMP7 exerted a stimulatory effect on basal E₂ production while BMP4 and BMP6 inhibited FSH-induced E₂ production. FSH receptor and aromatase expression were not different between both groups.

CONCLUSION

The BMP system is expressed in human GCs from normal cycling and PCOS women. The BMP may be involved in reproductive abnormalities found in PCOS.