RESUMEN
Macrophages are the principal immune cells of the epididymis and testis, but their origins, heterogeneity, development, and maintenance are not well understood. Here, we describe distinct populations of epididymal and testicular macrophages that display an organ-specific cellular identity. Combining in vivo fate-mapping, chimeric and parabiotic mouse models with in-depth cellular analyses, we found that CD64hiMHCIIlo and CD64loMHCIIhi macrophage populations of epididymis and testis arise sequentially from yolk sac erythro-myeloid progenitors, embryonic hematopoiesis, and nascent neonatal monocytes. While monocytes were the major developmental source of both epididymal and testicular macrophages, both populations self-maintain in the steady-state independent of bone marrow hematopoietic precursors. However, after radiation-induced macrophage ablation or during infection, bone marrow-derived circulating monocytes are recruited to the epididymis and testis, giving rise to inflammatory macrophages that promote tissue damage. These results define the layered ontogeny, maintenance and inflammatory response of macrophage populations in the male reproductive organs.
Asunto(s)
Infertilidad Masculina/inmunología , Macrófagos/inmunología , Macrófagos/metabolismo , Animales , Diferenciación Celular , Linaje de la Célula , Epidídimo/inmunología , Epidídimo/metabolismo , Infertilidad Masculina/metabolismo , Infertilidad Masculina/fisiopatología , Masculino , Ratones , Ratones Endogámicos C57BL , Monocitos/inmunología , Testículo/inmunología , Testículo/metabolismoRESUMEN
RESEARCH QUESTION: What is the impact of radiation exposure on oocyte quality and female fertility? DESIGN: Prepubertal mice underwent whole-body irradiation with a single dose (0.02, 0.1, 0.5, 2, 8 Gy) of gamma- or X-rays. Oocytes were quantified in irradiated (nâ¯=â¯36) and sham-treated (nâ¯=â¯8) mice. After a single exposure to 2 Gy, formation of DNA double-strand breaks (nâ¯=â¯10), activation of checkpoint kinase (Chk2) (nâ¯=â¯10) and dynamics of follicular growth (nâ¯=â¯18) were analysed. Fertility assessment was performed in adult irradiated mice and controls from the number of pups per mouse (nâ¯=â¯28) and the fetal abortion rate (nâ¯=â¯24). Ploidy of mature oocytes (nâ¯=â¯20) was analysed after CREST immunostaining, and uterine sections were examined. RESULTS: Radiation exposure induced a massive loss of primordial follicles with LD50 below 50 mGy for both gamma and X-rays. Growing follicles survived doses up to 8 Gy. This difference in radiosensitivity was not due to a different amount of radio-induced DNA damage, and Chk2 was activated in all oocytes. Exposure to a 2 Gy dose abolished the long-term fertility of females due to depletion of the ovarian reserve. Detailed analysis indicates that surviving oocytes were able to complete folliculogenesis and could be fertilized. This transient fertility allowed irradiated females to produce a single litter albeit with a high rate of fetal abortion (23%, Pâ¯=â¯0.0096), related to altered ploidy in the surviving oocytes (25.5%, Pâ¯=â¯0.0035). CONCLUSIONS: The effects of radiation on surviving oocyte quality question natural conception as a first-line approach in cancer survivors. Together, the data emphasize the need for fertility preservation before radiation exposure and call for reassessment of the use of cryopreserved oocytes.
Asunto(s)
Preservación de la Fertilidad/métodos , Oocitos/fisiología , Oocitos/efectos de la radiación , Ovario/efectos de la radiación , Insuficiencia Ovárica Primaria/etiología , Aborto Espontáneo , Aneuploidia , Animales , ADN/efectos de la radiación , Daño del ADN , Modelos Animales de Enfermedad , Relación Dosis-Respuesta en la Radiación , Femenino , Rayos gamma , Ratones , Ratones Endogámicos C57BL , Folículo Ovárico/efectos de la radiación , Reserva Ovárica/efectos de la radiación , Maduración Sexual/efectos de la radiación , Irradiación Corporal Total , Rayos XRESUMEN
For decades, numerous chemical pollutants have been described to interfere with endogenous hormone metabolism/signaling altering reproductive functions. Among these endocrine disrupting substances, Bisphenol A (BPA), a widely used compound, is known to negatively impact germ and somatic cells in the testis. Physical agents, such as ionizing radiation, were also described to perturb spermatogenesis. Despite the fact that we are constantly exposed to numerous environmental chemical and physical compounds, very few studies explore the impact of combined exposure to chemical and physical pollutants on reproductive health. The aim of this study was to describe the impact of fetal co-exposure to BPA and IR on testicular function in mice. We exposed pregnant mice to 10 µM BPA (corresponding to 0.5 mg/kg/day) in drinking water from 10.5 dpc until birth, and we irradiated mice with 0.2 Gy (γ-ray, RAD) at 12.5 days post-conception. Co-exposure to BPA and γ-ray induces DNA damage in fetal germ cells in an additive manner, leading to a long-lasting decrease in germ cell abundance. We also observed significant alteration of adult steroidogenesis by RAD exposure independently of the BPA exposure. This is illustrated by the downregulation of steroidogenic genes and the decrease of the number of adult Leydig cells. As a consequence, courtship behavior is modified, and male ultrasonic vocalizations associated with courtship decreased. In conclusion, this study provides evidence for the importance of broadening the concept of endocrine disruptors to include physical agents, leading to a reevaluation of risk management and regulatory decisions.
Asunto(s)
Compuestos de Bencidrilo/toxicidad , Rayos gamma/efectos adversos , Células Intersticiales del Testículo/metabolismo , Fenoles/toxicidad , Efectos Tardíos de la Exposición Prenatal/metabolismo , Traumatismos Experimentales por Radiación/metabolismo , Animales , Femenino , Células HeLa , Humanos , Células Intersticiales del Testículo/patología , Masculino , Ratones , Embarazo , Efectos Tardíos de la Exposición Prenatal/patología , Traumatismos Experimentales por Radiación/patologíaRESUMEN
Living species including humans are continuously exposed to low levels of a myriad of endocrine active compounds that may affect their reproductive function. In contrast, experimental designs scrutinizing this question mostly consider the gestational/lactational period, select high unrealistic doses and, have rarely investigated the possible reproductive consequences in the progeny. The present study aimed at assessing comparatively a set of male reproductive endpoints according to exposure windows, gestational/lactational versus pre-pubertal to adulthood, using low doses of endocrine active substances in male rats as well as their unexposed male progeny. Animals were orally exposed to 1 mg/kg bw/d of genistein and/or vinclozolin, from conception to weaning or from prepuberty to young adulthood. A number of reproductive endpoints were assessed as well as testicular mRNA expression profiles, in the exposed rats and their unexposed progeny. Overall, the low dosage used only affected weakly most of classical reproductive endpoints. However, the gestational/lactational exposure to vinclozolin alone or combined to genistein significantly delayed the puberty onset. Contrasting with the gestational/lactational exposure, a decreased sperm production was found in the animals exposed to genistein and vinclozolin from the pre-pubertal period but also in their progeny for vinclozolin and the mixture. The expression level of several genes involved in meiosis, apoptosis and steroidogenesis was also affected differentially as a function of the exposure window in both exposed rats and unexposed offspring. We also provide further evidence that doses of endocrine active substances relevant with human exposure may affect the male reproductive phenotype and testicular transcriptome in the exposed generation as well as in the indirectly exposed offspring.
Asunto(s)
Genisteína , Efectos Tardíos de la Exposición Prenatal , Adulto , Animales , Femenino , Expresión Génica , Genisteína/toxicidad , Humanos , Masculino , Oxazoles/toxicidad , Embarazo , Ratas , Testículo , Adulto JovenRESUMEN
Absence of mitosis and meiosis are distinguishing properties of male germ cells during late fetal and early neonatal periods. Repressors of male germ cell meiosis have been identified, but mitotic repressors are largely unknown, and no protein repressing both meiosis and mitosis is known. We demonstrate here that the zinc-finger protein BNC2 is present in male but not in female germ cells. In testis, BNC2 exists as several spliced isoforms and presumably binds to DNA. Within the male germ cell lineage, BNC2 is restricted to prospermatogonia and undifferentiated spermatogonia. Fetal prospermatogonia that lack BNC2 multiply excessively on embryonic day (E)14.5 and reenter the cell cycle prematurely. Mutant prospermatogonia also engage in abnormal meiosis; on E17.5, Bnc2(-/-) prospermatogonia start synthesizing the synaptonemal protein SYCP3, and by the time of birth, many Bnc2(-/-) prospermatogonia have accumulated large amounts of nonfilamentous SYCP3, thus appearing to be blocked at leptonema. Bnc2(-/-) prospermatogonia do not undergo proper male differentiation, as they lack almost all the mRNA for the male-specific methylation protein DNMT3L and have increased levels of mRNAs that encode meiotic proteins, including STRA8. Bnc2(-/-) prospermatogonia can produce spermatogonia, but these enter meiosis prematurely and undergo massive apoptotic death during meiotic prophase. This study identifies BNC2 as a major regulator of male germ stem cells, which is required for repression of meiosis and mitosis in prospermatogonia, and for meiosis progression during spermatogenesis. In view of the extreme evolutionary conservation of BNC2, the findings described here are likely to apply to many species.
Asunto(s)
Proteínas de Unión al ADN/metabolismo , Meiosis/fisiología , Mitosis/fisiología , Espermatogénesis/fisiología , Espermatogonias/fisiología , Animales , Proteínas de Ciclo Celular , ADN (Citosina-5-)-Metiltransferasas/metabolismo , Técnica del Anticuerpo Fluorescente Indirecta , Inmunohistoquímica , Masculino , Meiosis/genética , Ratones , Ratones Noqueados , Mitosis/genética , Proteínas Nucleares/biosíntesis , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Análisis de Secuencia de ARN , Espermatogénesis/genética , Espermatogonias/metabolismoRESUMEN
Pregnant Sprague-Dawley rats were administered deltamethrin, at doses 0.1, 1, 5 or 10 mg kg(-1) day(-1) , or di-n-hexyl phthalate (DnHP) (250 mg kg(-1) day(-1) ), by gavage, from gestational day 13 to 19. Maternal toxicity was observed at 10 mg kg(-1) day(-1) , as evidenced by transient clinical signs of neurotoxicity and reductions in body weight, body weight gain and corrected weight gain. Deltamethrin had no statistically significant effect on the incidence of post-implantation loss, fetal weight or anogenital distance in the male fetuses. Unlike DnHP, deltamethrin induced no changes in the expression of several genes involved in cholesterol transport or in the steroid synthesis pathway in the testes of gestational day 19.5 male fetuses (SRB1, StAR, P450scc, 3ßHSD, P450 17 A1, 17ßHSD). Fetal testicular levels of P450scc and P450 17 A1 protein were also unaffected by deltamethrin. No statistically significant differences were observed in the ex vivo fetal testicular production of testosterone and androstenedione after deltamethrin exposure, whereas DnHP markedly reduced these parameters. The deltamethrin metabolite, 3-phenoxybenzoic acid, was detected in amniotic fluid. In summary, our results demonstrate that in utero exposure to deltamethrin during the period of sexual differentiation had no significant effect on the testosterone synthesis pathway in the male rat fetus up to a maternal toxic dose. Copyright © 2016 John Wiley & Sons, Ltd.
Asunto(s)
Insecticidas/toxicidad , Nitrilos/toxicidad , Organogénesis/efectos de los fármacos , Efectos Tardíos de la Exposición Prenatal/inducido químicamente , Piretrinas/toxicidad , Testículo/efectos de los fármacos , Testosterona/biosíntesis , Animales , Femenino , Masculino , Exposición Materna , Embarazo , Efectos Tardíos de la Exposición Prenatal/metabolismo , Ratas Sprague-Dawley , Testículo/embriología , Testículo/metabolismoRESUMEN
Fetal testis is a major target of endocrine disruptors (EDs). During the last 20 years, we have developed an organotypic culture system that maintains the function of the different fetal testis cell types and have used this approach as a toxicological test to evaluate the effects of various compounds on gametogenesis and steroidogenesis in rat, mouse and human testes. We named this test rat, mouse and human fetal testis assay. With this approach, we compared the effects of six potential EDs ((mono-(2-ethylhexyl) phthalate (MEHP), cadmium, depleted uranium, diethylstilboestrol (DES), bisphenol A (BPA) and metformin) and one signalling molecule (retinoic acid (RA)) on the function of rat, mouse and human fetal testis at a comparable developmental stage. We found that the response is similar in humans and rodents for only one third of our analyses. For instance, RA and MEHP have similar negative effects on gametogenesis in the three species. For another third of our analyses, the threshold efficient concentrations that disturb gametogenesis and/or steroidogenesis differ as a function of the species. For instance, BPA and metformin have similar negative effects on steroidogenesis in human and rodents, but at different threshold doses. For the last third of our analyses, the qualitative response is species specific. For instance, MEHP and DES affect steroidogenesis in rodents, but not in human fetal testis. These species differences raise concerns about the extrapolation of data obtained in rodents to human health risk assessment and highlight the need of rigorous comparisons of the effects in human and rodent models, when assessing ED risk.
Asunto(s)
Experimentación Animal/normas , Disruptores Endocrinos/toxicidad , Roedores , Pruebas de Toxicidad/normas , Animales , Humanos , Masculino , Ratones , Modelos Animales , Ratas , Medición de Riesgo , Testículo/efectos de los fármacos , Pruebas de Toxicidad/métodosRESUMEN
In utero exposure to the phthalate ester plasticizer di-n-hexyl phthalate (DnHP) is known to affect the development of the male reproductive system and induce alterations in androgen-dependent tissues of male rat offspring. Male reproductive malformations produced by several phthalates have been causally linked to decreased testosterone production during the gestational period. This study was designed to evaluate the dose-response relationship for the effects of DnHP on the synthesis and production of testosterone in the fetal rat testis. Pregnant Sprague-Dawley rats were administered the vehicle (olive oil) and either DnHP (5 to 625 mg kg(-1) per day) or diethylhexyl phthalate (DEHP) (50 or 625 mg kg(-1) per day), by gavage, from gestation day (GD) 12 to19. Fetal testes were assessed on GD 19. DnHP reduced ex vivo testosterone production and down-regulated the expression of several genes required for cholesterol transport and steroid synthesis (i.e. SR-B1, StAR, P450scc, 3ßHSD and P450c17). These inhibitions were dose dependent. A no-effect level was established at 5 mg kg(-1) per day and a lowest-effect level at 20 mg kg(-1) per day. mRNA levels of SR-B1, StAR, P450scc and 3ßHSD were not similarly decreased in the adrenals. In conclusion, DnHP shares the same mode of action as DEHP in disrupting fetal testicular androgen synthesis. Alterations in testosterone production and in key steroidogenic gene expressions were apparent at lower doses than those causing postnatal reproductive malformations after gestational exposure during the critical period of male sexual differentiation. This suggests that they can be considered early biomarkers of DnHP-induced fetal testicular effects in rats.
Asunto(s)
Feto/efectos de los fármacos , Expresión Génica/efectos de los fármacos , Ácidos Ftálicos/toxicidad , Testículo/efectos de los fármacos , Testosterona/biosíntesis , Animales , Dietilhexil Ftalato/toxicidad , Relación Dosis-Respuesta a Droga , Regulación hacia Abajo , Femenino , Feto/patología , Masculino , Exposición Materna/efectos adversos , Nivel sin Efectos Adversos Observados , Ácidos Ftálicos/administración & dosificación , Plastificantes/toxicidad , Embarazo , Efectos Tardíos de la Exposición Prenatal/inducido químicamente , Efectos Tardíos de la Exposición Prenatal/patología , Ratas , Ratas Sprague-Dawley , Reproducción/efectos de los fármacos , Testículo/metabolismoRESUMEN
Many endocrine disruptors have been proven to impair the meiotic process which is required for the production of healthy gametes. Bisphenol A is emblematic of such disruptors, as it impairs meiotic prophase I and causes oocyte aneuploidy following in utero exposure. However, the mechanisms underlying these deleterious effects remain poorly understood. Furthermore, the increasing use of BPA alternatives raises concerns for public health. Here, we investigated the effects of foetal exposure to two BPA alternatives, bisphenol A Diglycidyl Ether (BADGE) and bisphenol AF (BPAF), on oogenesis in mice. These compounds delay meiosis initiation, increase the number of MLH1 foci per cell and induce oocyte aneuploidy. We further demonstrate that these defects are accompanied by changes in gene expression in foetal premeiotic germ cells and aberrant mRNA splicing of meiotic genes. We observed an increase in DNA oxidation after exposure to BPA alternatives. Specific induction of oxidative DNA damage during foetal germ cell differentiation causes similar defects during oogenesis, as observed in 8-oxoguanine DNA Glycosylase (OGG1)-deficient mice or after in utero exposure to potassium bromate (KBrO3), an inducer of oxidative DNA damage. The supplementation of BPA alternatives with N-acetylcysteine (NAC) counteracts the effects of bisphenols on meiosis. Together, our results propose oxidative DNA lesion as an event that negatively impacts female meiosis with major consequences on oocyte quality. This could be a common mechanism of action for numerous environmental pro-oxidant pollutants, and its discovery, could lead to reconsider the adverse effect of bisphenol mixtures that are simultaneously present in our environment.
Asunto(s)
Meiosis , Ovario , Femenino , Ratones , Animales , Compuestos de Bencidrilo/toxicidad , ADN , AneuploidiaRESUMEN
The generation of oocytes from induced pluripotent stem cells (iPSCs) was proven efficient with mouse cells. However, no human iPSCs have yet been reported to generate cells able to complete oogenesis. Additionally, efficient sorting of human Primordial Germ Cell-like Cells (hPGC-LCs) without genomic integration of fluorescent reporter for their downstream manipulation is still lacking. Here, we aimed to develop a model that allows human germ cell differentiation in vitro in order to study the developing human germline. The hPGC-LCs specified from two iPS cell lines were sorted and manipulated using the PDPN surface marker without genetic modification. hPGC-LCs obtained remain arrested at early stages of maturation and no further differentiation nor meiotic onset occurred when these were cultured with human or mouse fetal ovarian somatic cells. However, when cultured independently of somatic ovarian cells, using BMP4 and the hanging drop-transferred EBs system, early hPGC-LCs further differentiate efficiently and express late PGC (DDX4) and meiotic gene markers, although no SYCP3 protein was detected. Altogether, we characterized a tool to sort hPGC-LCs and an efficient in vitro differentiation system to obtain pre-meiotic germ cell-like cells without using a gonadal niche.
Asunto(s)
Células Germinativas , Células Madre Pluripotentes Inducidas , Femenino , Humanos , Ratones , Animales , Células Germinativas/metabolismo , Diferenciación Celular , Células Madre Pluripotentes Inducidas/metabolismo , Línea Celular , Oocitos , Glicoproteínas de Membrana/metabolismoRESUMEN
A functional balance between excitatory and inhibitory control over dopamine (DA)-dependent behavioral and neurochemical effects of cocaine is afforded by the serotonin(2C) receptor (5-HT(2C)R) located within the ventral tegmental area and the nucleus accumbens (NAc). The 5-HT(2C)R located in the medial prefrontal cortex (mPFC) has also been shown to inhibit cocaine-induced behaviors perhaps through inhibition of DA function in the NAc. Using in vivo microdialysis in halothane-anesthetized rats, we tested this hypothesis by assessing the influence of mPFC 5-HT(2C)Rs on cocaine-induced DA outflow in the NAc shell. Intra-mPFC injection of the 5-HT(2C)R agonist Ro 60-0175 at 5 microg/0.2 microl, but not 1 microg/0.2 microl, potentiated the increase in accumbal DA outflow induced by the intraperitoneal administration of 10 mg/kg of cocaine. Conversely, cocaine-induced accumbal DA outflow was significantly reduced by the intra-mPFC injection of the selective 5-HT(2C)R antagonist SB 242084 (0.5 microg/0.2 microl) or SB 243213 (0.5 and 1 microg/0.2 microl). These results show that mPFC 5-HT(2C)Rs exert a positive control over cocaine-induced accumbal DA outflow. Observations further support the idea that the overall action of central 5-HT(2C)Rs on accumbal DA output is dependent on the functional balance among different 5-HT(2C)R populations located within the mesocorticoaccumbens system, and that 5-HT(2C)Rs can modulate DA-dependent behaviors independently of changes of accumbal DA release itself.
Asunto(s)
Cocaína/farmacología , Inhibidores de Captación de Dopamina/farmacología , Dopamina/metabolismo , Núcleo Accumbens/efectos de los fármacos , Corteza Prefrontal/metabolismo , Receptor de Serotonina 5-HT2C/fisiología , Aminopiridinas/farmacología , Análisis de Varianza , Animales , Electroquímica/métodos , Etilaminas/farmacología , Indoles/farmacología , Masculino , Microdiálisis/métodos , Núcleo Accumbens/metabolismo , Piridinas/farmacología , Ratas , Ratas Sprague-Dawley , Agonistas del Receptor de Serotonina 5-HT2 , Antagonistas del Receptor de Serotonina 5-HT2RESUMEN
BACKGROUND: Several studies have described an increasing frequency of male reproductive disorders, which may have a common origin in fetal life and which are hypothesized to be caused by endocrine disruptors. Phthalate esters represent a class of environmental endocrine-active chemicals known to disrupt development of the male reproductive tract by decreasing testosterone production in the fetal rat. OBJECTIVES: Using the organ culture system we developed previously, we investigated the effects on the development of human fetal testis of one phthalate--mono-2-ethylhexyl phthalate (MEHP)--an industrial chemical found in many products, which has been incriminated as a disruptor of male reproductive function. METHODS: Human fetal testes were recovered during the first trimester (7-12 weeks) of gestation, a critical period for testicular differentiation, and cultured for 3 days with or without MEHP in basal conditions or stimulated with luteinizing hormone (LH). RESULTS: Whatever the dose, MEHP treatment had no effect on basal or LH-stimulated testosterone produced by the human fetal testis in vitro, although testosterone production can be modulated in our culture system. MEHP (10(-4) M) did not affect proliferation or apoptosis of Sertoli cells, but it reduced the mRNA expression of anti-Müllerian hormone. MEHP (10(-4) M) reduced the number of germ cells by increasing their apoptosis, measured by the detection of caspase-3-positive germ cells, without modification of their proliferation. CONCLUSIONS: This is the first experimental demonstration that phthalates alter the development of the germ cell lineage in humans. However, in contrast to results observed in the rat, phthalates did not affect steroidogenesis.
Asunto(s)
Células Germinativas/efectos de los fármacos , Ácidos Ftálicos/toxicidad , Testículo/efectos de los fármacos , Testosterona/biosíntesis , Células Germinativas/citología , Humanos , Masculino , Radioinmunoensayo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Testículo/citología , Testículo/embriología , Testículo/metabolismoRESUMEN
In female mammals, germ cells enter meiosis in the fetal ovaries, while in males, meiosis is prevented until postnatal development. Retinoic acid (RA) is considered the main inducer of meiotic entry, as it stimulates Stra8 which is required for the mitotic/meiotic switch. In fetal testes, the RA-degrading enzyme CYP26B1 prevents meiosis initiation. However, the role of endogenous RA in female meiosis entry has never been demonstrated in vivo. In this study, we demonstrate that some effects of RA in mouse fetal gonads are not recapitulated by the invalidation or up-regulation of CYP26B1. In organ culture of fetal testes, RA stimulates testosterone production and inhibits Sertoli cell proliferation. In the ovaries, short-term inhibition of RA-signaling does not decrease Stra8 expression. We develop a gain-of-function model to express CYP26A1 or CYP26B1. Only CYP26B1 fully prevents STRA8 induction in female germ cells, confirming its role as part of the meiotic prevention machinery. CYP26A1, a very potent RA degrading enzyme, does not impair the formation of STRA8-positive cells, but decreases Stra8 transcription. Collectively, our data reveal that CYP26B1 has other activities apart from metabolizing RA in fetal gonads and suggest a role of endogenous RA in amplifying Stra8, rather than being the initial inducer of Stra8. These findings should reactivate the quest to identify meiotic preventing or inducing substances.
Asunto(s)
Gónadas/metabolismo , Ácido Retinoico 4-Hidroxilasa/metabolismo , Tretinoina/metabolismo , Animales , Línea Celular , Proliferación Celular , Gónadas/citología , Células HEK293 , Humanos , Ratones , Ratones Endogámicos , Ratones Mutantes , Receptores de Ácido Retinoico/metabolismo , Testosterona/análisis , Testosterona/biosíntesisRESUMEN
Stimulation of central serotonin2C receptor (5-HT(2C)R) inhibits dopamine (DA)-dependent neurochemical and behavioral effects of cocaine, while 5-HT(2C)Rs locally expressed into the ventral tegmental area (VTA) and the nucleus accumbens (NAc) exert opposite functional control over cocaine-induced behavioral effects. Using in vivo microdialysis in halothane-anesthetized rats, we tested the hypothesis that this functionally opposite regulation of the mesoaccumbens DA pathway relies on the ability of 5-HT(2C)Rs in the VTA and the NAc to inhibit and enhance respectively cocaine-induced accumbal DA outflow. Intra-VTA injection of the 5-HT(2C)R agonist Ro 60-0175 at 5 microg/0.2 microl, but not 1 microg/0.2 microl, attenuated the increase in accumbal DA outflow induced by the systemic administration of 10 mg/kg of cocaine. Intra-VTA injection of the 5-HT(2C)R antagonist SB 242084 at either dose (0.1 or 0.5 microg/0.2 microl) did not modify the effects of cocaine. Intra-NAc application of Ro 60-0175 dose-dependently excited (0.1 microM) and inhibited (1 microM) cocaine-induced DA outflow. In contrast, intra-NAc application of SB 242084 resulted in diametrically opposite effects when applied at these concentrations. These results further support the idea that the overall action of central 5-HT(2C)Rs on accumbal DA output is dependent, at least in part, on the functional balance between different 5-HT(2C)R populations within the NAc and within the mesoaccumbens DA pathway (VTA vs NAc).
Asunto(s)
Cocaína/farmacología , Dopamina/metabolismo , Núcleo Accumbens/fisiología , Receptor de Serotonina 5-HT2C/fisiología , Área Tegmental Ventral/fisiología , Aminopiridinas/farmacología , Animales , Cocaína/administración & dosificación , Etilaminas/administración & dosificación , Etilaminas/farmacología , Indoles/administración & dosificación , Indoles/farmacología , Masculino , Microdiálisis , Núcleo Accumbens/efectos de los fármacos , Ratas , Ratas Sprague-Dawley , Receptor de Serotonina 5-HT2C/efectos de los fármacos , Antagonistas de la Serotonina/farmacología , Área Tegmental Ventral/efectos de los fármacosRESUMEN
BACKGROUND: Using an organotypic culture system termed human Fetal Testis Assay (hFeTA) we previously showed that 0.01 µM BPA decreases basal, but not LH-stimulated, testosterone secreted by the first trimester human fetal testis. The present study was conducted to determine the potential for a long-term antiandrogenic effect of BPA using a xenograft model, and also to study the effect of BPA on germ cell development using both the hFETA and xenograft models. METHODS: Using the hFeTA system, first trimester testes were cultured for 3 days with 0.01 to 10 µM BPA. For xenografts, adult castrate male nude mice were injected with hCG and grafted with first trimester testes. Host mice received 10 µM BPA (~ 500 µg/kg/day) in their drinking water for 5 weeks. Plasma levels of total and unconjugated BPA were 0.10 µM and 0.038 µM respectively. Mice grafted with second trimester testes received 0.5 and 50 µg/kg/day BPA by oral gavage for 5 weeks. RESULTS: With first trimester human testes, using the hFeTA model, 10 µM BPA increased germ cell apoptosis. In xenografts, germ cell density was also reduced by BPA exposure. Importantly, BPA exposure significantly decreased the percentage of germ cells expressing the pluripotency marker AP-2γ, whilst the percentage of those expressing the pre-spermatogonial marker MAGE-A4 significantly increased. BPA exposure did not affect hCG-stimulated androgen production in first and second trimester xenografts as evaluated by both plasma testosterone level and seminal vesicle weight in host mice. CONCLUSIONS: Exposure to BPA at environmentally relevant concentrations impairs germ cell development in first trimester human fetal testis, whilst gonadotrophin-stimulated testosterone production was unaffected in both first and second trimester testis. Studies using first trimester human fetal testis demonstrate the complementarity of the FeTA and xenograft models for determining the respective short-term and long term effects of environmental exposures.
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Compuestos de Bencidrilo/toxicidad , Contaminantes Ambientales/toxicidad , Células Intersticiales del Testículo/efectos de los fármacos , Fenoles/toxicidad , Espermatozoides/efectos de los fármacos , Testículo/efectos de los fármacos , Animales , Femenino , Xenoinjertos , Humanos , Masculino , Ratones , Ratones Desnudos , Embarazo , Primer Trimestre del Embarazo , Segundo Trimestre del Embarazo , Radioinmunoensayo , Reacción en Cadena en Tiempo Real de la Polimerasa , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Testículo/citología , Testículo/embriología , Testosterona/sangreRESUMEN
Sexual reproduction is crucially dependent on meiosis, a conserved, specialized cell division programme that is essential for the production of haploid gametes. Here we demonstrate that fertility and the implementation of the meiotic programme require a previously uncharacterized meiosis-specific protein, MEIOC. Meioc invalidation in mice induces early and pleiotropic meiotic defects in males and females. MEIOC prevents meiotic transcript degradation and interacts with an RNA helicase that binds numerous meiotic mRNAs. Our results indicate that proper engagement into meiosis necessitates the specific stabilization of meiotic transcripts, a previously little-appreciated feature in mammals. Remarkably, the upregulation of MEIOC at the onset of meiosis does not require retinoic acid and STRA8 signalling. Thus, we propose that the complete induction of the meiotic programme requires both retinoic acid-dependent and -independent mechanisms. The latter process involving post-transcriptional regulation likely represents an ancestral mechanism, given that MEIOC homologues are conserved throughout multicellular animals.
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Proteínas de Ciclo Celular/genética , Células Germinativas/metabolismo , Gónadas/metabolismo , Profase Meiótica I/genética , ARN Mensajero/metabolismo , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Animales , Western Blotting , Proteínas de Ciclo Celular/metabolismo , Femenino , Técnica del Anticuerpo Fluorescente , Células Germinativas/patología , Gónadas/patología , Células HEK293 , Humanos , Inmunohistoquímica , Inmunoprecipitación , Masculino , Meiosis/genética , Ratones , Ratones Noqueados , Reacción en Cadena en Tiempo Real de la Polimerasa , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Análisis de Matrices Tisulares , Tretinoina/metabolismoRESUMEN
During the last decades, many studies reported that male reproductive disorders are increasing among humans. It is currently acknowledged that these abnormalities can result from fetal exposure to environmental chemicals that are progressively becoming more concentrated and widespread in our environment. Among the chemicals present in the environment (air, water, food, and many consumer products), several can act as endocrine disrupting compounds (EDCs), thus interfering with the endocrine system. Phthalates, bisphenol A (BPA), and diethylstilbestrol (DES) have been largely incriminated, particularly during the fetal and neonatal period, due to their estrogenic and/or anti-androgenic properties. Indeed, many epidemiological and experimental studies have highlighted their deleterious impact on fetal and neonatal testis development. As EDCs can affect many different genomic and non-genomic pathways, the mechanisms underlying the adverse effects of EDC exposure are difficult to elucidate. Using literature data and results from our laboratory, in the present review, we discuss the role of classical nuclear receptors (genomic pathway) in the fetal and neonatal testis response to EDC exposure, particularly to phthalates, BPA, and DES. Among the nuclear receptors, we focused on some of the most likely candidates, such as peroxisome-proliferator activated receptor (PPAR), androgen receptor (AR), estrogen receptors (ERα and ß), liver X receptors (LXR), and small heterodimer partner (SHP). First, we describe the expression and potential functions (based on data from studies using receptor agonists and mouse knockout models) of these nuclear receptors in the developing testis. Then, for each EDC studied, we summarize the main evidences indicating that the reprotoxic effect of each EDC under study is mediated through a specific nuclear receptor(s). We also point-out the involvement of other receptors and nuclear receptor-independent pathways.
RESUMEN
Bisphenol A (BPA) is a widely studied typical endocrine-disrupting chemical, and one of the major new issues is the safe replacement of this commonly used compound. Bisphenol S (BPS) and bisphenol F (BPF) are already or are planned to be used as BPA alternatives. With the use of a culture system that we developed (fetal testis assay [FeTA]), we previously showed that 10 nmol/L BPA reduces basal testosterone secretion of human fetal testis explants and that the susceptibility to BPA is at least 100-fold lower in rat and mouse fetal testes. Here, we show that addition of LH in the FeTA system considerably enhances BPA minimum effective concentration in mouse and human but not in rat fetal testes. Then, using the FeTA system without LH (the experimental conditions in which mouse and human fetal testes are most sensitive to BPA), we found that, as for BPA, 10 nmol/L BPS or BPF is sufficient to decrease basal testosterone secretion by human fetal testes with often nonmonotonic dose-response curves. In fetal mouse testes, the dose-response curves were mostly monotonic and the minimum effective concentrations were 1,000 nmol/L for BPA and BPF and 100 nmol/L for BPS. Finally, 10,000 nmol/L BPA, BPS, or BPF reduced Insl3 expression in cultured mouse fetal testes. This is the first report describing BPS and BPF adverse effects on a physiologic function in humans and rodents.
Asunto(s)
Compuestos de Bencidrilo/toxicidad , Compuestos Epoxi/toxicidad , Fenoles/toxicidad , Efectos Tardíos de la Exposición Prenatal/inducido químicamente , Efectos Tardíos de la Exposición Prenatal/fisiopatología , Sulfonas/toxicidad , Testículo/efectos de los fármacos , Testículo/embriología , Animales , Relación Dosis-Respuesta a Droga , Sustitución de Medicamentos/efectos adversos , Sustitución de Medicamentos/métodos , Disruptores Endocrinos/toxicidad , Contaminantes Ambientales/toxicidad , Femenino , Humanos , Masculino , Ratones , Embarazo , Ratas , Medición de Riesgo , Especificidad de la EspecieRESUMEN
In this study, using the new sigma(1/2) (sigma(1/2)) compound MR200, its parent drug haloperidol and the sigma ligand 1,3-di-o-tolylguanidine (DTG), we have investigated the role of striatal sigma receptors in the control of basal dopamine (DA) outflow, by coupling in vitro binding experiments and in vivo microdialysis in the striatum of halothane-anesthetized rats. MR200 with respect to haloperidol, exhibits high affinity for sigma(1) (1.5 nM) and sigma(2) (21.9 nM) receptors, but only negligible affinity for DA receptors. Compared to DTG, MR200 has similar selectivity across neurotransmitter systems, and 46 times higher affinity for sigma(1) receptors. Intrastriatal application of MR200 at 10, but not 0.1 or 1 microM, elicited a pronounced decrease in striatal DA release (-45% of control values). This inhibitory effect was preceded by a transient increase in DA release (+50% over baseline) after 100 microM MR200 administration. DTG at 100, but not 10 microM, significantly reduced DA release (-40%). Haloperidol, whilst increasing DA release at 1 microM, induced a delayed decrease in DA release after 10 microM application. Finally, haloperidol (10 microM) did not modify the inhibitory effect of 10 microM MR200. These results show that striatal sigma receptors control striatal DA release in resting conditions.