RESUMO
Noncovalent complexes of transforming growth factor-ß family growth/differentiation factors with their prodomains are classified as latent or active, depending on whether the complexes can bind their respective receptors. For the anti-Müllerian hormone (AMH), the hormone-prodomain complex is active, and the prodomain is displaced upon binding to its type II receptor, AMH receptor type-2 (AMHR2), on the cell surface. However, the mechanism by which this displacement occurs is unclear. Here, we used ELISA assays to measure the dependence of prodomain displacement on AMH concentration and analyzed results with respect to the behavior expected for reversible binding in combination with ligand-induced receptor dimerization. We found that, in solution, the prodomain has a high affinity for the growth factor (GF) (Kd = 0.4 pM). Binding of the AMH complex to a single AMHR2 molecule does not affect this Kd and does not induce prodomain displacement, indicating that the receptor binding site in the AMH complex is fully accessible to AMHR2. However, recruitment of a second AMHR2 molecule to bind the ligand bivalently leads to a 1000-fold increase in the Kd for the AMH complex, resulting in rapid release of the prodomain. Displacement occurs only if the AMHR2 is presented on a surface, indicating that prodomain displacement is caused by a conformational change in the GF induced by bivalent binding to AMHR2. In addition, we demonstrate that the bone morphogenetic protein 7 prodomain is displaced from the complex with its GF by a similar process, suggesting that this may represent a general mechanism for receptor-mediated prodomain displacement in this ligand family.
Assuntos
Hormônio Antimülleriano , Hormônios Peptídicos , Hormônio Antimülleriano/metabolismo , Ligantes , Hormônios Peptídicos/metabolismo , Domínios Proteicos , Receptores de Fatores de Crescimento Transformadores beta/metabolismo , Fator de Crescimento Transformador beta/metabolismoRESUMO
Down syndrome (DS), or Trisomy 21, is the most common chromosomal disorder in humans. Men with DS are infertile. The DYRK1A gene on Hsa21 is involved in several features of DS. Overexpression of the homolog dyrk1A disrupts primordial germ cell migration in zebrafish, and overexpression of Dyrk1A impairs gonadotropic axis function and the early stages of spermatogenesis in the mouse. Other genes on Hsa21 might be involved in the pathogenesis of infertility in DS. We investigated the Dp(16)1Yey mouse model of DS, which features segmental duplication of chromosome Mmu16 (orthologous to a large part of Hsa21 and carrying Dyrk1A and 112 other genes). Using an immunohistochemical assay for the spermatogonial marker STRA8, we observed spermatogonial depletion in the Dp(16)1Yey mouse. This was correlated with low mRNA expression of GFRï¡1 (a marker of the self-renewal stem cell pool) in an RT-qPCR assay and low protein expression of PLZF (a marker of differentiating stem cells) in a slot-blot assay. Spermatogenesis was present but impaired, with a low sperm count, low protamine-1 expression, a low testis weight, and a low seminiferous tubule diameter. Low circulating luteinizing hormone and follicle-stimulating hormone levels and an elevated testis anti-Müllerian hormone level (as measured in ELISAs) revealed the presence of hypogonadotropic hypogonadism. The Dp(16)1Yey mouse model of DS recapitulates observations made in zebrafish and mice overexpressing DYRK1A homologs. The presence of an excess of Mmu16 material perturbs spermatogenesis and the gonadotropic axis. More generally, DYRK1A's role in human infertility (outside DS) remains to be characterized.
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Testicular anti-Müllerian hormone (AMH) production is inhibited by androgens around pubertal onset, as observed under normal physiological conditions and in patients with precocious puberty. In agreement, AMH downregulation is absent in patients with androgen insensitivity. The molecular mechanisms underlying the negative regulation of AMH by androgens remain unknown. Our aim was to elucidate the mechanisms through which androgens downregulate AMH expression in the testis. A direct negative effect of androgens on the transcriptional activity of the AMH promoter was found using luciferase reporter assays in the mouse prepubertal Sertoli cell line SMAT1. A strong inhibition of AMH promoter activity was seen in the presence of both testosterone and DHT and of the androgen receptor. By site-directed mutagenesis and chromatin immunoprecipitation assays, we showed that androgen-mediated inhibition involved the binding sites for steroidogenic factor 1 (SF1) present in the proximal promoter of the AMH gene. In this study, we describe for the first time the mechanism behind AMH inhibition by androgens, as seen in physiological and pathological conditions in males. Inhibition of AMH promoter activity by androgens could be due to protein-protein interactions between the ligand-bound androgen receptor and SF1 or by blockage of SF1 binding to its sites on the AMH promoter.
Assuntos
Androgênios/farmacologia , Hormônio Antimülleriano/metabolismo , Células de Sertoli/fisiologia , Fator Esteroidogênico 1/metabolismo , Animais , Hormônio Antimülleriano/genética , Linhagem Celular , Imunoprecipitação da Cromatina , Regulação para Baixo , Humanos , Imuno-Histoquímica , Masculino , Camundongos , Regiões Promotoras Genéticas , Receptores Androgênicos/metabolismo , Fator Esteroidogênico 1/genética , TranscriptomaRESUMO
This article reviews the main findings on anti-Müllerian hormone (AMH) and its involvement in the pathogenesis of polycystic ovary syndrome (PCOS) and its male equivalent. In women, AMH is produced by granulosa cells from the mid-fetal life to menopause and is a reliable indirect marker of ovarian reserve. AMH protects follicles from atresia, inhibits their differentiation in the ovary, and stimulates gonadotrophin-releasing hormone neurons pulsatility. AMH overexpression in women with PCOS likely contributes to the increase of the follicle cohort and of androgen levels, leading to follicular arrest and anovulation. In the male, AMH is synthesized at high levels by Sertoli cells from fetal life to puberty when serum AMH falls to levels similar to those observed in women. AMH is involved in the differentiation of the genital tract during fetal life and plays a role in Sertoli and Leydig cells differentiation and function. Serum AMH is used to assess Sertoli cell function in children with disorders of sex development and various conditions affecting the hypothalamic-pituitary-testicular axis. Although the reproductive function of male relative of women with PCOS has been poorly investigated, adolescents have elevated levels of AMH which could play a detrimental role on their fertility.
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In adult testis, the cell mobility is essential for spermatogonia differentiation and is suspected to regulate spermatogonial stem cell fate. Netrin-1 controls cell migration and/or survival according to the cellular context. Its involvement in some self-renewing lineages raises the possibility that Netrin-1 could have a role in spermatogenesis. We show that in addition to Sertoli cells, a fraction of murine undifferentiated spermatogonia express the Netrin-1 receptor UNC5c and that UNC5c contributes to spermatogonia differentiation. Receptor loss in Unc5crcm males leads to the concomitant accumulation of transit-amplifying progenitors and short syncytia of spermatogonia. Without altering cell death rates, the consequences of Unc5c loss worsen with age: the increase in quiescent undifferentiated progenitors associated with a higher spermatogonial stem cell enriched subset leads to the spermatocyte I decline. We demonstrate in vitro that Netrin-1 promotes a guidance effect as it repulses both undifferentiated and differentiating spermatogonia. Finally, we propose that UNC5c triggers undifferentiated spermatogonia adhesion/ migration and that the repulsive activity of Netrin-1 receptors could regulate spermatogonia differentiation, and maintain germ cell homeostasis.
Assuntos
Espermatogênese , Espermatogônias , Animais , Diferenciação Celular/fisiologia , Homeostase , Masculino , Camundongos , Receptores de Netrina/metabolismo , Netrina-1/metabolismo , Espermatogênese/fisiologia , TestículoRESUMO
BACKGROUND: Excess weight and metabolic disorders have a negative impact on male reproductive functions. The mechanisms involved are numerous and complex and epigenetic mechanisms may also be involved, notably through the small non-coding RNAs. Among them, microRNAs (miRNAs) are of particular interest. This preliminary study aimed to identify the miRNAs differentially enriched in seminal plasma related to metabolic disorders and if some are also associated with spermatic parameters alterations. One hundred and sixty men between 18 to 45 years, partners of infertile couple, were included in this cohort. The miRNAs associated with metabolism were selected from the literature and assayed by quantitative real-time PCR using TaqMan gene expression assays. A subset of those with an interesting profile in seminal plasma were secondarily tested in blood. RESULTS: Among the 11 selected miRNAs, seven were detected in seminal plasma (miR10b, miR19a, miR19b, miR34b, miR34c, miR133b, miRlet7c). A negative correlation was observed between seminal miR19a levels and metabolic syndrome, blood glucose and C-peptide. Seminal miR19b levels were also negatively correlated with metabolic syndrome. Seminal miR34c levels were negatively correlated with body mass index (BMI) and waist circumference. Seminal miR133b levels were positively correlated with BMI, waist circumference and leptin levels. Interestingly, modifications of miRNAs in seminal plasma seem specific since highlighted above correlations were not retrieved in the blood plasma for the miR19a, 19b, 10b, 34c. CONCLUSION: Few metabolic and anthropometric disorders are correlated with the level of specific miRNAs in seminal plasma. Further studies will be required to decipher if other small non-coding RNAs may also be correlated with metabolic and anthropometric disorders and to assess their potential implication in the alteration of reproductive functions in men with obesity or metabolic disorders. CLINICAL STUDY: Metabolic Syndrome and Male Infertility (Metasperme): Trial registration: NCT01974947 . Registered 18 July 2013.
RéSUMé: CONTEXTE: L'excès de poids et les troubles métaboliques ont un impact négatif sur les fonctions de reproduction masculine. Les mécanismes impliqués sont nombreux et complexes, et des mécanismes épigénétiques peuvent également intervenir, notamment par le biais des petits ARN non codants. Parmi eux, les microRNAs (miRNAs) présentent un intérêt particulier. Cette étude préliminaire visait à identifier les miRNAs différentiellement enrichis dans le plasma séminal en relation avec des troubles métaboliques et si certains étaient également associés à des altérations des paramètres spermatiques. Cent soixante hommes âgés de 18 à 45 ans, partenaires de couple infertile, ont été inclus dans cette cohorte. Les miRNAs associés au métabolisme ont été sélectionnés dans la littérature et analysés par PCR quantitative en temps réel à l'aide de tests d'expression génique TaqMan. Un sous-ensemble de ceux présentant un profil intéressant dans le plasma séminal ont été secondairement testés dans le sang. RéSULTATS: Parmi les 11 miRNAs sélectionnés, sept ont été détectés dans le plasma séminal (miR10b, miR19a, miR19b, miR34b, miR34c, miR133b, miRlet7c). Une corrélation négative a été observée entre les niveaux du miR19a séminal et le syndrome métabolique, la glycémie et le C-peptide. Les niveaux de miR19b séminaux étaient également corrélés négativement avec le syndrome métabolique. Les niveaux de miR34c séminaux étaient négativement corrélés avec l'IMC et le tour de taille. Les niveaux de miR133b séminaux étaient positivement corrélés avec l'IMC, le tour de taille et les niveaux de leptine. Il est intéressant de noter que les modifications des miRNA dans le plasma séminal semblent spécifiques puisque les corrélations mises en évidence ci-dessus n'ont pas été retrouvées dans le plasma sanguin pour les miR19a, 19b, 10b, 34c. CONCLUSION: Quelques désordres métaboliques et anthropométriques ont été observés corrélés avec le niveau de certains miRNAs dans le plasma séminal. Des études complémentaires sont nécessaires pour déterminer si d'autres petits ARN non codants sont corrélés aux troubles métaboliques et anthropométriques et pour évaluer leur implication potentielle dans l'altération des fonctions de reproduction chez les hommes souffrant d'obésité ou de troubles métaboliques.
RESUMO
Anti-Müllerian hormone (AMH), also called Müllerian inhibiting substance, was shown to be synthesized by the ovary in the 1980s. This article reviews the main findings of the past 20 years on the regulation of the expression of AMH and its specific receptor AMHR2 by granulosa cells, the mechanism of action of AMH, the different roles it plays in the reproductive organs, its clinical utility, and its involvement in the principal pathological conditions affecting women. The findings in respect of regulation tell us that AMH and AMHR2 expression is mainly regulated by bone morphogenetic proteins, gonadotropins, and estrogens. It has now been established that AMH regulates the different steps of folliculogenesis and that it has neuroendocrine effects. On the other hand, the importance of serum AMH as a reliable marker of ovarian reserve and as a useful tool in the prediction of the polycystic ovary syndrome (PCOS) and primary ovarian failure has also been acknowledged. Last but not least, a large body of evidence points to the involvement of AMH in the pathogenesis of PCOS.
Assuntos
Hormônios Peptídicos , Síndrome do Ovário Policístico , Hormônio Antimülleriano/metabolismo , Feminino , Células da Granulosa , Humanos , Hormônios Peptídicos/metabolismo , Síndrome do Ovário Policístico/metabolismo , ReproduçãoRESUMO
Down syndrome (DS) is the most common chromosomal disorder. It is responsible for intellectual disability (ID) and several medical conditions. Although men with DS are thought to be infertile, some spontaneous paternities have been reported. The few studies of the mechanism of infertility in men with DS are now dated. Recent research in zebrafish has indicated that overexpression of DYRK1A (the protein primarily responsible for ID in DS) impairs gonadogenesis at the embryonic stage. To better ascertain DYRK1A's role in infertility in DS, we investigated the effect of DYRK1A overexpression in a transgenic mouse model. We found that overexpression of DYRK1A impairs fertility in transgenic male mice. Interestingly, the mechanism in mice differs slightly from that observed in zebrafish but, with disruption of the early stages of spermatogenesis, is similar to that seen in humans. Unexpectedly, we observed hypogonadotropic hypogonadism in the transgenic mice.
Assuntos
Hipogonadismo/genética , Infertilidade Masculina/genética , Proteínas Serina-Treonina Quinases/genética , Proteínas Tirosina Quinases/genética , Espermatogênese , Animais , Hipogonadismo/patologia , Infertilidade Masculina/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Tirosina Quinases/metabolismo , Testículo/embriologia , Testículo/patologia , Regulação para Cima , Quinases DyrkRESUMO
Polycystic ovary syndrome (PCOS) is characterized by an oligo-anovulation, hyperandrogenism and polycystic ovarian morphology combined with major metabolic disturbances. However, despite the high prevalence and the human and economic consequences of this syndrome, its etiology remains unknown. In this study, we show that female Goto-Kakizaki (GK) rats, a type 2 diabetes mellitus model, encapsulate naturally all the reproductive and metabolic hallmarks of lean women with PCOS at puberty and in adulthood. The analysis of their gestation and of their fetuses demonstrates that this PCOS-like phenotype is developmentally programmed. GK rats also develop features of ovarian hyperstimulation syndrome. Lastly, a comparison between GK rats and a cohort of women with PCOS reveals a similar reproductive signature. Thus, this spontaneous rodent model of PCOS represents an original tool for the identification of the mechanisms involved in its pathogenesis and for the development of novel strategies for its treatment.
Assuntos
Síndrome do Ovário Policístico/patologia , Adiposidade , Animais , Animais Recém-Nascidos , Peso Corporal , Análise Discriminante , Modelos Animais de Doenças , Dislipidemias/patologia , Sistema Endócrino/patologia , Ciclo Estral , Feminino , Teste de Tolerância a Glucose , Gonadotropinas/farmacologia , Hormônios/sangue , Humanos , Secreção de Insulina , Análise dos Mínimos Quadrados , Lipídeos/química , Masculino , Troca Materno-Fetal , Análise Multivariada , Ovário/patologia , Ovário/fisiopatologia , Fenótipo , Síndrome do Ovário Policístico/sangue , Síndrome do Ovário Policístico/fisiopatologia , Gravidez , Ratos Wistar , Reprodução , Maturidade SexualRESUMO
PURPOSE: A protective effect of anti-Müllerian hormone (AMH) on follicle atresia was recently demonstrated using long-term treatments, but this effect has never been supported by mechanistic studies. This work aimed to gain an insight into the mechanism of action of AMH on follicle atresia and on how this could account for the increased follicle pool observed in women with polycystic ovary syndrome (PCOS). METHODS: In vivo and in vitro experiments were performed to study the effects of AMH on follicle atresia and on the proliferation and apoptosis of granulosa cells (GCs). RNA-sequencing was carried out to identify new AMH target genes in GCs. The expression of some of these genes in GCs from control and PCOS women was compared using microfluidic real time quantitative RT-PCR. RESULTS: A short-term AMH treatment prevented follicle atresia in prepubertal mice. Consistent with this result, AMH inhibited apoptosis and promoted proliferation of different models of GCs. Moreover, integrative biology analyses of 965 AMH target genes identified in 1 of these GC models, confirmed that AMH had initiated a gene expression program favoring cell survival and proliferation. Finally, on 43 genes selected among the most up- and down-regulated AMH targets, 8 were up-regulated in GCs isolated from PCOS women, of which 5 are involved in cell survival. MAIN CONCLUSIONS: Our results provide for the first time cellular and molecular evidence that AMH protects follicles from atresia by controlling GC survival and suggest that AMH could participate in the increased follicle pool of PCOS patients.
Assuntos
Hormônio Antimülleriano/farmacologia , Apoptose , Células da Granulosa/efeitos dos fármacos , Síndrome do Ovário Policístico/patologia , Adulto , Animais , Hormônio Antimülleriano/metabolismo , Apoptose/efeitos dos fármacos , Apoptose/genética , Estudos de Casos e Controles , Proliferação de Células/efeitos dos fármacos , Proliferação de Células/genética , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/genética , Células Cultivadas , Feminino , Regulação da Expressão Gênica/efeitos dos fármacos , Células da Granulosa/patologia , Células da Granulosa/fisiologia , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Síndrome do Ovário Policístico/genética , Síndrome do Ovário Policístico/metabolismoRESUMO
Epidemiological studies have demonstrated an increased risk of developing non-transmittable diseases in adults subjected to adverse early developmental conditions. Metabolic and cardiovascular diseases have been the focus of most studies. Nevertheless, data from animal models also suggest early programming of fertility. In humans, it is difficult to assess the impact of the in utero environment retrospectively. Birthweight is commonly used as an indirect indicator of intrauterine development. This research is part of the ALIFERT study. We investigated a potential link between ponderal index at birth and female fertility in adulthood. Data from 51 infertile and 74 fertile women were analysed. BW was on average higher in infertile women, whereas birth length did not differ between the two groups; thus, resulting in a significantly higher ponderal index at birth in infertile women. Ponderal index at birth has been identified as a risk factor for infertility. These results suggest the importance of the intra-uterine environment, not only for long-term metabolic health but also for fertility.
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Peso ao Nascer/fisiologia , Estatura/fisiologia , Transtornos da Nutrição Fetal/epidemiologia , Infertilidade Feminina/epidemiologia , Adolescente , Adulto , Estudos de Casos e Controles , Feminino , Fertilidade/fisiologia , Transtornos da Nutrição Fetal/diagnóstico , Transtornos da Nutrição Fetal/fisiopatologia , Humanos , Infertilidade Feminina/fisiopatologia , Gravidez , Estudos Prospectivos , Estudos Retrospectivos , Fatores de Risco , Circunferência da Cintura/fisiologia , Adulto JovemRESUMO
Anti-Müllerian hormone (AMH) is secreted by Sertoli cells of the testes from early fetal life until puberty, when it is downregulated by androgens. In conditions like complete androgen insensitivity syndrome (CAIS), AMH downregulation does not occur and AMH increases at puberty, due in part to follicle-stimulating hormone (FSH) effect. However, other conditions like Peutz-Jeghers syndrome (PJS), characterised by low FSH, also have increased AMH. Because both CAIS and PJS may present as hyperoestrogenic states, we tested the hypothesis that oestradiol (E2) upregulates AMH expression in peripubertal Sertoli cells and explored the molecular mechanisms potentially involved. The results showed that E2 is capable of inducing an upregulation of endogenous AMH and of the AMH promoter activity in the prepubertal Sertoli cell line SMAT1, signalling through ERα binding to a specific ERE sequence present on the hAMH promoter. A modest action was also mediated through the membrane oestrogen receptor GPER. Additionally, the existence of ERα expression in Sertoli cells in patients with CAIS was confirmed by immunohistochemistry. The evidence presented here provides biological plausibility to the hypothesis that testicular AMH production increases in clinical conditions in response to elevated oestrogen levels.
Assuntos
Síndrome de Resistência a Andrógenos/metabolismo , Hormônio Antimülleriano/metabolismo , Receptor alfa de Estrogênio/biossíntese , Proteínas de Neoplasias/biossíntese , Síndrome de Peutz-Jeghers/metabolismo , Elementos de Resposta , Células de Sertoli/metabolismo , Síndrome de Resistência a Andrógenos/patologia , Animais , Linhagem Celular , Criança , Pré-Escolar , Estradiol/metabolismo , Feminino , Humanos , Masculino , Camundongos , Síndrome de Peutz-Jeghers/patologia , Células de Sertoli/patologiaRESUMO
: Fat gain is reported in integrase strand transfer inhibitors exposed persons living with HIV. We investigated in 165 persons living with HIV (117 men/48 women), included in the 96-week ANRS-163-ETRAL trial and switched to raltegravir/etravirine, the impact of sex, menopausal status and ovarian reserve (detectable anti-Müllerian hormone). From baseline to 48/96 weeks, women with ovarian reserve were protected from raltegravir/etravirine-induced weight/fat gain and associated insulin-resistance while peri/postmenopausal women increased weight, fat and insulin resistance as did men. The functional ovarian status could protect against raltegravir/etravirine-induced weight gain.
Assuntos
Infecções por HIV , Nitrilas/uso terapêutico , Pirimidinas/uso terapêutico , Raltegravir Potássico/uso terapêutico , Fármacos Anti-HIV/efeitos adversos , Feminino , Infecções por HIV/tratamento farmacológico , Inibidores de Integrase de HIV/uso terapêutico , Humanos , Masculino , Raltegravir Potássico/efeitos adversosRESUMO
Male sex differentiation is driven by 2 hormones, testosterone and anti-müllerian hormone (AMH), responsible for the regression of müllerian ducts in male fetuses. Mutations inactivating AMH or its receptor AMHRII lead to the persistent müllerian duct syndrome (PMDS) in otherwise normally virilized 46,XY males. Our objective was to review the clinical, anatomical, and molecular features of PMDS based upon a review of the literature and upon 157 personal cases. Three clinical presentations exist: bilateral cryptorchidism, unilateral cryptorchidism with contralateral hernia, and transverse testicular ectopia. Abnormalities of male excretory ducts are frequent. Testicular malignant degeneration occurs in 33% of adults with the disorder, while cancer of müllerian derivatives is less frequent. Fertility is rare but possible if at least one testis is scrotal and its excretory ducts are intact. Eighty families with 64 different mutations of the AMH gene have been identified, mostly in exons 1, 2, and 5. AMHRII gene mutations representing 58 different alleles have been discovered in 75 families. The most common mutation, a 27-bp deletion in the kinase domain, was found in 30 patients of mostly Northern European origin. In 12% of cases, no mutation of AMH or AMHRII has been detected, suggesting a disruption of other pathways involved in müllerian regression.
Assuntos
Transtorno 46,XY do Desenvolvimento Sexual/patologia , Hormônio Antimülleriano/química , Hormônio Antimülleriano/genética , Transtorno 46,XY do Desenvolvimento Sexual/genética , Hormônios/metabolismo , Humanos , Padrões de Herança/genética , Modelos Moleculares , Mutação/genéticaRESUMO
Context: Anti-Müllerian hormone (AMH) and AMH type II receptor (AMHR2) are overexpressed in granulosa cells (GCs) from women with polycystic ovary syndrome (PCOS), the most common cause of female infertility. Objective: The aim of the study was to compare the regulation of the AMH/AMHR2 system by 5α-dihydrotestosterone (5α-DHT) and estradiol (E2) in GCs from control subjects and women with PCOS. Design, Setting, Patients: Experiments were performed on follicular fluids (FF) and GCs from women undergoing in vitro fertilization. Main Outcome Measures: FF steroid levels were measured by mass spectrometry, and messenger RNA (mRNA) accumulation was quantified by reverse transcription real-time polymerase chain reaction. Results: Total testosterone (T), free T, and 5α-DHT FF levels were significantly higher (P < 0.001) in women with PCOS than in controls. However, E2 and sex hormone-binding globulin concentrations were comparable between the two groups. In GCs from control women, the AMH and AMHR2 expression were not affected by 5α-DHT treatment, whereas AMH mRNA levels were upregulated by 5α-DHT in GCs from patients with PCOS (2.3-fold, P < 0.01) overexpressing the androgen receptor (1.4-fold, P < 0.05). E2 downregulated the AMH and AMHR2 expression in GCs from control women (1.4-fold, P < 0.001 and 1.8-fold, P < 0.01, respectively) but had no effect on these genes in GCs from women with PCOS. This differential effect of E2 was associated with a higher estrogen receptor 1 expression in GCs from women with PCOS (1.9-fold, P < 0.05). Conclusions: In GCs from women with PCOS, the regulation of AMH and AMHR2 expression is altered in a way that promotes the overexpression of the AMH/AMHR2 system, and could contribute to the follicular arrest observed in these patients.
Assuntos
Hormônio Antimülleriano/genética , Di-Hidrotestosterona/farmacologia , Estradiol/farmacologia , Síndrome do Ovário Policístico/genética , Receptores de Peptídeos/genética , Receptores de Fatores de Crescimento Transformadores beta/genética , Adulto , Hormônio Antimülleriano/metabolismo , Estudos de Casos e Controles , Di-Hidrotestosterona/metabolismo , Estradiol/metabolismo , Receptor alfa de Estrogênio/genética , Receptor alfa de Estrogênio/metabolismo , Receptor beta de Estrogênio/genética , Receptor beta de Estrogênio/metabolismo , Feminino , Fase Folicular/efeitos dos fármacos , Fase Folicular/genética , Fase Folicular/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Células da Granulosa/efeitos dos fármacos , Células da Granulosa/metabolismo , Humanos , Síndrome do Ovário Policístico/metabolismo , Receptores Androgênicos/genética , Receptores Androgênicos/metabolismo , Receptores de Peptídeos/metabolismo , Receptores de Fatores de Crescimento Transformadores beta/metabolismo , Adulto JovemRESUMO
CONTEXT: Anti-Müllerian hormone (AMH) is produced by the granulosa cells (GCs) of growing follicles and inhibits follicular development. OBJECTIVE: This study aimed to investigate the regulation of the AMH-specific type 2 receptor (AMHR2) gene expression in GCs by bone morphogenetic protein (BMP)15, BMP4 and growth differentiation factor (GDF)9. DESIGN, SETTING, AND PATIENTS: Their effects on AMHR2 and AMH mRNAs were studied in luteinized human GCs and in ovine GCs (oGCs) from small antral follicles. The effects of BMPs on human AMHR2 and AMH promoter reporter activities were analyzed in transfected oGCs. The in vivo effect of BMP15 on GCs AMHR2 and AMH expression was investigated by using Lacaune and Rasa Aragonesa hyperprolific ewes carrying loss-of-function mutations in BMP15. MAIN OUTCOME MEASURES: mRNAs were quantified by real-time RT-PCR. Promoter reporter constructs activities were quantified by the measurement of their luciferase activity. RESULTS: BMP15 and BMP4 enhanced AMHR2 and AMH expression in human GCs and in oGCs, whereas GDF9 had no effect. In oGCs, GDF9 increased BMP15 effect on AMH expression. Consistent with these results, BMP15 and BMP4, but not GDF9, enhanced AMHR2 promoter activity in oGCs, whereas GDF9 increased BMP15 effect on AMH promoter activity. Moreover, oGCs from both BMP15 mutant ewes had reduced AMHR2 mRNA levels but unchanged AMH expression compared with wild-type ewes. CONCLUSIONS: Altogether, these results suggest that the mechanisms of action of BMP15 on AMHR2 and AMH expression are different, and that by stimulating AMHR2 and AMH expression in GCs BMP15 enhances AMH inhibitory actions in GCs.
Assuntos
Proteína Morfogenética Óssea 15/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Células da Granulosa/efeitos dos fármacos , Receptores de Peptídeos/metabolismo , Receptores de Fatores de Crescimento Transformadores beta/metabolismo , Regulação para Cima/efeitos dos fármacos , Adulto , Animais , Proteína Morfogenética Óssea 4/farmacologia , Feminino , Células da Granulosa/metabolismo , Fator 9 de Diferenciação de Crescimento/farmacologia , Humanos , Folículo Ovariano/efeitos dos fármacos , Folículo Ovariano/metabolismo , Regiões Promotoras Genéticas/efeitos dos fármacos , Receptores de Peptídeos/genética , Receptores de Fatores de Crescimento Transformadores beta/genética , Ovinos , Adulto JovemRESUMO
Anti-Müllerian hormone (AMH) contributes to male sexual differentiation and acts on gonads of both sexes. Identification of AMH receptivity in both pituitary and brain has led to the intriguing idea that AMH participates to the hypothalamic-pituitary control of reproduction, however in vivo experimental evidence is still lacking. We show that AMH stimulates secretion and pituitary gene expression of the gonadotropin FSH in vivo in rats. AMH action is sex-dependent, being restricted to females and occurring before puberty. Accordingly, we report higher levels of pituitary AMH receptor transcripts in immature females. We show that AMH is functionally coupled to the Smad pathway in LßT2 gonadotrope cells and dose-dependently increases Fshb transcript levels. Furthermore, AMH was shown to establish complex interrelations with canonical FSH regulators as it cooperates with activin to induce Fshb expression whereas it reduces BMP2 action. We report that GnRH interferes with AMH by decreasing AMH receptivity in vivo in females. Moreover, AMH specifically regulates FSH and not LH, indicating that AMH is a factor contributing to the differential regulation of gonadotropins. Overall, our study uncovers a new role for AMH in regulating gonadotrope function and suggests that AMH participates in the postnatal elevation of FSH secretion in females.
Assuntos
Hormônio Antimülleriano/genética , Hormônio Foliculoestimulante/genética , Gonadotrofos/metabolismo , Adeno-Hipófise/metabolismo , Receptores de Peptídeos/genética , Receptores de Fatores de Crescimento Transformadores beta/genética , Caracteres Sexuais , Ativinas/genética , Ativinas/metabolismo , Animais , Animais Recém-Nascidos , Hormônio Antimülleriano/metabolismo , Proteína Morfogenética Óssea 2/genética , Proteína Morfogenética Óssea 2/metabolismo , Linhagem Celular , Feminino , Hormônio Foliculoestimulante/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Gonadotrofos/citologia , Hormônio Liberador de Gonadotropina/genética , Hormônio Liberador de Gonadotropina/metabolismo , Hipotálamo/metabolismo , Hormônio Luteinizante/genética , Hormônio Luteinizante/metabolismo , Masculino , Adeno-Hipófise/citologia , Adeno-Hipófise/crescimento & desenvolvimento , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ratos , Ratos Wistar , Receptores de Peptídeos/metabolismo , Receptores de Fatores de Crescimento Transformadores beta/metabolismo , Maturidade Sexual , Transdução de Sinais , Proteínas Smad/genética , Proteínas Smad/metabolismoRESUMO
CONTEXT: Anti-Müllerian hormone (AMH) is an important clinical marker for diagnosing and assessing the reproductive status and/or disorders in men and women. Most studies have not distinguished between levels of inactive AMH precursor and the cleaved noncovalent complex that binds the AMH type II receptor (AMHRII) and initiates signaling. OBJECTIVE: The objective of the study was to measure the levels of AMH cleavage and bioactivity in human body fluids. DESIGN, SETTING, AND PATIENTS: AMH cleavage levels and bioactivity were measured in the serum of six boys and in the follicular fluid and serum of nine control women and 13 women with the polycystic ovary syndrome (PCOS). MAIN OUTCOME MEASURES: AMH cleavage levels were measured by capturing AMH with an anti-AMH antibody, followed by Western blotting. The bioactivity of cleaved AMH was assessed with an ELISA that measures the levels of AMH capable of binding AMHRII. RESULTS: PCOS women have an elevated level of AMH cleavage in their follicular fluid (24% vs 8% in control women), and most of the cleaved AMH can bind AMHRII. Higher levels of cleavage are observed in female (60%) and male (79%) serum, but very little of the cleaved AMH can bind AMHRII. CONCLUSIONS: These results support an autocrine role for AMH in the pathophysiology of PCOS in the follicle. In addition, they indicate that AMH undergoes interactions or structural changes after cleavage that prevent receptor binding, meaning, unexpectedly, that the level of cleaved AMH in biological fluids does not always reflect the level of bioactive AMH.
Assuntos
Hormônio Antimülleriano/metabolismo , Líquido Folicular/metabolismo , Síndrome do Ovário Policístico/metabolismo , Receptores de Peptídeos/metabolismo , Receptores de Fatores de Crescimento Transformadores beta/metabolismo , Adulto , Hormônio Antimülleriano/sangue , Criança , Feminino , Humanos , Masculino , Síndrome do Ovário Policístico/sangue , Ligação ProteicaRESUMO
It is now accepted that estrogens play a role in male fertility and that exposure to exogenous estrogens during fetal/neonatal life can lead to reproductive disorders in the male. However, the estrogen receptor (ER)-mediated processes involved in the regulation of male reproduction during fetal and neonatal development are still largely unclear. We previously reported that ER beta deficiency affects gametogenesis in mice but changes neither the number nor the differentiated functions of fetal Leydig cells. We show here that ER alpha-deficient mice (ER alpha-/-) display higher levels of testicular testosterone secretion than wild-type mice from fetal d 13.5 onwards. This results from higher levels of steroidogenic activity per fetal Leydig cell, as indicated by the hypertrophy of these cells and the higher levels of mRNA for StAR, P450c17 and P450scc in the testis, for a similar number of Leydig cells. Because LH is not produced on fetal d 13.5 and because no change in plasma LH concentration was observed in 2-d-old ER alpha-deficient mice, LH is probably not involved in the effects of estrogens on testicular steroidogenesis in fetal and early neonatal Leydig cells. Furthermore, inactivation of ER beta did not change the effect of ER alpha inactivation on steroidogenesis. Lastly, in an organ culture system, 1 mum diethylstilbestrol decreased the testosterone secretion of wild-type fetal and neonatal testes but not of ER alpha-/- testes. Thus, this study shows that endogenous estrogens physiologically inhibit steroidogenesis via ER alpha by acting directly on the testis early in fetal and neonatal development.
Assuntos
Receptor alfa de Estrogênio/fisiologia , Estrogênios/fisiologia , Feto/citologia , Células Intersticiais do Testículo/fisiologia , Animais , Animais Recém-Nascidos/crescimento & desenvolvimento , Enzima de Clivagem da Cadeia Lateral do Colesterol/genética , Dietilestilbestrol/farmacologia , Receptor alfa de Estrogênio/deficiência , Feminino , Células Intersticiais do Testículo/química , Hormônio Luteinizante/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Técnicas de Cultura de Órgãos , Fosfoproteínas/genética , Gravidez , RNA Mensageiro/análise , Esteroide 17-alfa-Hidroxilase/genética , Testículo/embriologia , Testículo/crescimento & desenvolvimento , Testículo/metabolismo , Testosterona/metabolismoRESUMO
Although the role of pituitary hormones in fetal Sertoli cell proliferation is well understood, their involvement in fetal Sertoli cell differentiation is poorly documented. In this study, we evaluated rat fetal Sertoli cell function by measuring basal transferrin secretion ex vivo and transferrin and anti-Müllerian hormone (AMH) mRNA levels in vivo. The differentiation state of the Sertoli cells was estimated from the amount of transferrin secreted ex vivo after acute stimulation with FSH. Surprisingly, we found that the amount of transferrin secreted by each Sertoli cell in basal condition and after acute FSH stimulation decreased between 18.5 and 21.5 day post coitum (dpc), which corresponds to the onset of pituitary hormone secretion. All of the Sertoli cell parameters measured (basal and FSH-stimulated transferrin secretion ex vivo, transferrin and AMH mRNA levels in vivo) were higher in 21.5-dpc fetuses that had been decapitated on 16.5 dpc than in control littermates. Furthermore, immunostaining for AMH was strongly increased after decapitation. Taken together, these results suggest that pituitary hormones in the fetus and in the immature or adult rat differently regulate Sertoli cells, which suggests that fetal Sertoli cells have their own particular physiology.