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1.
Int J Mol Sci ; 24(15)2023 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-37569429

RESUMO

We demonstrate here that highly sensitive in vitro bioassays for FSH, TSH, and PTH can be set up in mouse Leydig Tumor Cells (mLTC), in addition to the normal LH/CG bioassay, after they were transfected with expression vectors encoding the corresponding Gs Protein-Coupled Receptors (GsPCR), such as FSHR, TSHR, or PTHR. Although the ß2 adrenergic receptor is also a GsPCR, its expression in mLTC led to a significant but very low cAMP response compared to those observed with FSH, TSH, or PTH. Similarly, after transfection of the GiPCR MT1 melatonin receptor, we did not observe any inhibitory effect by melatonin of the LH or hCG stimulation. Interestingly, after transfection of mLTC with the human kisspeptin receptor (hKpR), which is a GqPCR, we observed a dose-dependent synergy of 10-12-10-7 M kisspeptin variants with a fixed concentration of 0.3 nM LH or hCG. Without any exogenous receptor transfection, a 2 h preincubation with OT or AVP led to a dose-dependent cAMP response to a fixed dose of LH or hCG. Therefore, highly sensitive in vitro bioassays for various hormones and other GPCR ligands can be set up in mLTC to measure circulating concentrations in only 3-10 µL of blood or other body fluids. Nevertheless, the development of an LHRKO mLTC cell line will be mandatory to obtain strict specificity for these bioassays to eliminate potential cross-reaction with LH or CG.


Assuntos
Kisspeptinas , Receptores do LH , Camundongos , Animais , Humanos , Receptores do LH/genética , Receptores do LH/metabolismo , Kisspeptinas/metabolismo , Ligantes , AMP Cíclico/metabolismo , Transdução de Sinais , Receptores Acoplados a Proteínas G , Hormônio Foliculoestimulante/farmacologia , Hormônio Foliculoestimulante/metabolismo , Tireotropina/metabolismo , Gonadotropina Coriônica/metabolismo
2.
Reprod Domest Anim ; 58 Suppl 2: 109-124, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37329313

RESUMO

Pulsatile secretion of gonadotropin-releasing hormone (GnRH) is essential for the activation and maintenance of the function of the hypothalamic-pituitary-gonadal (HPG) axis, which controls the onset of puberty and fertility. Two provocative recent studies suggest that, in addition to control reproduction, the neurons in the brain that produce GnRH are also involved in the control postnatal brain maturation, odour discrimination and adult cognition. Long-acting GnRH antagonists and agonists are commonly used to control fertility and behaviour in veterinary medicine, primarily in males. This review puts into perspective the potential risks of these androgen deprivation therapies and immunization on olfactory and cognitive performances and well-aging in domestic animals, including pets. We will also discuss the results reporting beneficial effects of pharmacological interventions restoring physiological GnRH levels on olfactory and cognitive alterations in preclinical models of Alzheimer's disease, which shares many pathophysiological and behavioural hallmarks with canine cognitive dysfunction. These novel findings raise the intriguing possibility that pulsatile GnRH therapy holds therapeutic potential for the management of this behavioural syndrome affecting older dogs.


Assuntos
Doenças do Cão , Neoplasias da Próstata , Masculino , Animais , Cães , Hormônio Liberador de Gonadotropina , Olfato , Antagonistas de Androgênios , Neoplasias da Próstata/veterinária , Cognição
3.
J Chem Neuroanat ; 125: 102149, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-36058434

RESUMO

In mammals, reproductive function is under the control of hypothalamic neurons named Gonadotropin-Releasing Hormone (GnRH) neurons. These neurons migrate from the olfactory placode to the brain, during embryonic development. For the past 40 years, these neurons have been considered an example of tangential migration, i.e., dependent on the olfactory/vomeronasal/terminal nerves. Numerous studies have highlighted the factors involved in the migration of these neurons but thus far overlooked the cellular microenvironment that produces them. Many of these factors are dysregulated in hypogonadotropic hypogonadism, resulting in subfertility/infertility. Nevertheless, over the past ten years, several papers have reported the influence of glial cells (named olfactory ensheathing cells [OECs]) in the migration and differentiation of GnRH neurons. This review will describe the atypical origins, migration, and differentiation of these neurons, focusing on the latest discoveries. There will be a more specific discussion on the involvement of OECs in the development of GnRH neurons, during embryonic and perinatal life; as well as on their potential implication in the development of congenital or idiopathic hypogonadotropic hypogonadism (such as Kallmann syndrome).


Assuntos
Hormônio Liberador de Gonadotropina , Síndrome de Kallmann , Animais , Adulto , Humanos , Movimento Celular/fisiologia , Neuroglia , Neurônios/fisiologia , Mamíferos
4.
Mol Cell Endocrinol ; 557: 111752, 2022 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-35973528

RESUMO

Hypothalamic control of reproduction relies on GnRH and kisspeptin (KP) secretions. KP neurons are sensitive to sex steroids and metabolic status and their distribution overlaps with neurons producing apelin, a metabolic hormone known to decrease LH secretion in rats. Here, we observed neuroanatomical contacts between apelin fibers and both KP and GnRH neurons in the hypothalamus of male rodents. Intracerebroventricular apelin infusion for 2 weeks in male mice did not decrease LH levels nor did it affect gene expression for KP, neurokinin B and dynorphin. Finally, increasing apelin concentrations did not modulate Ca2+ levels of cultured GnRH neurons, while 10 µM apelin infusion on forskolin pretreated GnRH neurons revoked a rhythmic activity in 18% of GnRH neurons. These results suggest that acute apelin effect on LH secretion does not involve modulation of gene expression in KP neurons but may affect the secretory activity of GnRH neurons.


Assuntos
Hormônio Liberador de Gonadotropina , Neurocinina B , Animais , Apelina , Receptores de Apelina , Núcleo Arqueado do Hipotálamo/metabolismo , Colforsina/farmacologia , Dinorfinas/genética , Hormônio Liberador de Gonadotropina/metabolismo , Kisspeptinas/metabolismo , Hormônio Luteinizante/metabolismo , Hormônio Luteinizante/farmacologia , Masculino , Camundongos , Neurocinina B/genética , Neurônios/metabolismo , Ratos , Esteroides/metabolismo
5.
J Neuroendocrinol ; 34(5): e13087, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35067985

RESUMO

This review summarizes the current understanding of the development of the neuroendocrine gonadotropin-releasing hormone (GnRH) system, including discussion on open questions regarding (1) transcriptional regulation of the Gnrh1 gene; (2) prenatal development of the GnRH1 system in rodents and humans; and (3) paracrine and synaptic communication during migration of the GnRH cells.


Assuntos
Hormônio Liberador de Gonadotropina , Neurônios , Feminino , Regulação da Expressão Gênica , Hormônio Liberador de Gonadotropina/metabolismo , Humanos , Neurônios/metabolismo , Sistemas Neurossecretores/metabolismo , Gravidez
6.
Int J Biostat ; 18(2): 627-675, 2022 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-34598374

RESUMO

We present in this paper a global methodology for the spike detection in a biological context of fluorescence recording of GnRH-neurons calcium activity. For this purpose we first propose a simple stochastic model that could mimic experimental time series by considering an autoregressive AR(1) process with a linear trend and specific innovations involving spiking times. Estimators of parameters with asymptotic normality are established and used to set up a statistical test on estimated innovations in order to detect spikes. We compare several procedures and illustrate on biological data the performance of our procedure.


Assuntos
Cálcio , Neurônios , Potenciais de Ação/fisiologia , Neurônios/fisiologia
7.
J Neuroendocrinol ; 33(11): e13037, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34533248

RESUMO

Kisspeptin (Kp), a family of peptides comprising products of the Kiss1 gene, was discovered 20 years ago; it is recognised as the major factor controlling the activity of the gonadotrophin-releasing hormone (GnRH) neurones and thus the activation of the reproductive axis in mammals. It has been widely documented that the effects of Kp on reproduction through its action on GnRH neurones are mediated by the GPR54 receptor. Kp controls the activation of the reproductive axis at puberty, maintains reproductive axis activity in adults and is involved in triggering ovulation in some species. Although there is ample evidence coming from both conditional knockout models and conditional-induced Kp neurone death implicating the Kp/GPR54 pathway in the control of reproduction, the mechanism(s) underlying this process may be more complex than a sole direct control of GnRH neuronal activity by Kp. In this review, we provide an overview of the recent advances made in elucidating the interplay between Kp- and GnRH- neuronal networks with respect to regulating the reproductive axis. We highlight the existence of a possible mutual regulation between GnRH and Kp neurones, as well as the implication of Kp-dependent volume transmission in this process. We also discuss the capacity of heterodimerisation between GPR54 and GnRH receptor (GnRH-R) and its consequences on signalling. Finally, we illustrate the role of mathematical modelling that accounts for the synergy between GnRH-R and GPR54 in explaining the role of these two receptors when defining GnRH neuronal activity and GnRH pulsatile release.


Assuntos
Hormônio Liberador de Gonadotropina , Kisspeptinas , Animais , Feminino , Hormônio Liberador de Gonadotropina/metabolismo , Kisspeptinas/metabolismo , Mamíferos , Receptores Acoplados a Proteínas G/metabolismo , Receptores de Kisspeptina-1 , Maturidade Sexual/fisiologia
8.
Sci Rep ; 10(1): 10654, 2020 06 30.
Artigo em Inglês | MEDLINE | ID: mdl-32606357

RESUMO

The control of ovulation helps guarantee the success of reproduction and as such, contributes to the fitness of a species. In mammals, two types of ovulation are observed: induced and spontaneous ovulation. Recent work on camelids, that are induced ovulators, highlighted the role of a factor present in seminal plasma, beta Nerve Growth Factor (ß-NGF), as the factor that triggers ovulation in a GnRH dependent manner. In the present work, we characterized alpaca ß-NGF (aß-NGF) and its 3D structure and compared it with human recombinant ß-NGF (hß-NGF). We showed that the ß-NGF enriched fraction of alpaca semen and the human recombinant protein, both stimulated spontaneous electrical activity of primary GnRH neurons derived from mouse embryonic olfactory placodes. This effect was dose-dependent and mediated by p75 receptor signaling. P75 receptors were found expressed in vitro by olfactory ensheathing cells (OEC) in close association with GnRH neurons and in vivo by tanycytes in close vicinity to GnRH fibers in adult mouse. Altogether, these results suggested that ß-NGF induced ovulation through an increase in GnRH secretion provoked by a glial dependent P75 mediated mechanism.


Assuntos
Hormônio Liberador de Gonadotropina/metabolismo , Fator de Crescimento Neural/farmacologia , Neurônios/efeitos dos fármacos , Animais , Estimulantes do Sistema Nervoso Central/farmacologia , Corpo Lúteo/efeitos dos fármacos , Corpo Lúteo/metabolismo , Feminino , Humanos , Masculino , Camundongos , Neurônios/metabolismo , Ovulação/efeitos dos fármacos , Ovulação/metabolismo , Indução da Ovulação/métodos , Proteínas Recombinantes/metabolismo , Reprodução/efeitos dos fármacos , Sêmen/efeitos dos fármacos
9.
Eur J Neurosci ; 46(10): 2596-2607, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28973792

RESUMO

During mammalian embryonic development, GnRH neurones differentiate from the nasal placode and migrate through the nasal septum towards the forebrain. We previously showed that a category of glial cells, the olfactory ensheathing cells (OEC), forms the microenvironment of migrating GnRH neurones. Here, to characterize the quantitative and qualitative importance of this glial, we investigated the spatiotemporal maturation of glial cells in situ and the role of maturing glia in GnRH neurones development ex vivo. More than 90% of migrating GnRH neurones were found to be associated with glial cells. There was no change in the cellular microenvironment of GnRH neurones in the regions crossed during embryonic development as glial cells formed the main microenvironment of these neurones (53.4%). However, the phenotype of OEC associated with GnRH neurones changed across regions. The OEC progenitors immunoreactive to brain lipid binding protein formed the microenvironment of migrating GnRH neurones from the vomeronasal organ to the telencephalon and were also present in the diencephalon. However, during GnRH neurone migration, maturation of OEC to [GFAP+] state (glial fibrillary acid protein) was only observed in the nasal septum. Inducing depletion of OEC in maturation, using transgenic mice expressing herpes simplex virus thymidine kinase driven by the GFAP promoter, had no impact on neurogenesis or on triggering GnRH neurones migration in nasal explant culture. Nevertheless, depletion of [GFAP+] cells decreased GnRH neurites outgrowth by 57.4%. This study suggests that specific maturation of OEC in the nasal septum plays a role in morphological differentiation of GnRH neurones.


Assuntos
Hormônio Liberador de Gonadotropina/metabolismo , Neuritos/fisiologia , Neuroglia/fisiologia , Crescimento Neuronal , Neurônios/fisiologia , Bulbo Olfatório/crescimento & desenvolvimento , Animais , Movimento Celular , Camundongos , Camundongos Transgênicos , Septo Nasal/crescimento & desenvolvimento , Células-Tronco Neurais/fisiologia , Neuroglia/metabolismo , Neurônios/metabolismo , Bulbo Olfatório/metabolismo , Técnicas de Cultura de Órgãos , Células-Tronco , Órgão Vomeronasal/crescimento & desenvolvimento
10.
Theriogenology ; 86(1): 313-23, 2016 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-27177964

RESUMO

During adulthood, the mammalian brain retains the capacity to generate new cells and new neurons in particular. It is now well established that the birth of these new neurons occurs in well-described sites: the hippocampus and the subventricular zone of the lateral ventricle, as well as in other brain regions including the hypothalamus. In this review, we describe the canonical neurogenic niches and illustrate the functional relevance of adult-born neurons of each neurogenic niche in the reproductive physiology. More specifically, we highlight the effect of reproductive social stimuli on the neurogenic processes and conversely, the contributions of adult-born neurons to the reproductive physiology and behavior. We next review the recent discovery of a novel neurogenic niche located in the hypothalamus and the median eminence and the compelling evidence of the link existing between the new-born hypothalamic neurons and the regulation of metabolism. In addition, new perspectives on the possible involvement of hypothalamic neurogenesis in the control of photoperiodic reproductive physiology in seasonal mammals are discussed. Altogether, the studies highlighted in this review demonstrate the potential role of neurogenesis in reproductive function and emphasize the importance of increasing our knowledge on the regulation processes and the physiological relevance of these adult-born neurons. This constitutes a necessary step toward a potential manipulation of these plasticity mechanisms.


Assuntos
Encéfalo/crescimento & desenvolvimento , Mamíferos/fisiologia , Neurogênese/fisiologia , Reprodução/fisiologia , Animais , Encéfalo/citologia
11.
FEBS J ; 283(10): 1902-20, 2016 05.
Artigo em Inglês | MEDLINE | ID: mdl-26990886

RESUMO

Intracellular cytoplasmic calcium ([Ca(2+) ]i ) has an important regulatory role in gamete functions. However, the biochemical components involved in Ca(2+) transport are still unknown in birds, an animal class that has lost functional sperm-specific CatSper channels. Here, we provide evidence for the presence and expression of various Ca(2+) channels in chicken sperm, including high voltage-activated channels (L and R types), the store-operated Ca(2+) channel (SOC) component Orai1, the transient receptor potential channel (TRPC1) and inositol-1,4,5-trisphosphate receptors (IP3 R1). L- and R-type channels were mainly localized in the acrosome and the midpiece, and T-type channels were not detected in chicken sperm. Orai1 was found in all compartments, but with a weak, diffuse signal in the flagellum. TRCP1 was mainly localized in the acrosome and the midpiece, but a weak diffuse signal was also observed in the nucleus and the flagellum. IP3 R1 was mainly detected in the nucleus. The L-type channel inhibitor nifedipine, the R-type channel inhibitor SNX-482 and the SOC inhibitors MRS-1845, 2-APB and YM-58483 decreased [Ca(2+) ]i sperm motility and acrosome reaction capability, with the SOC inhibitors inhibiting these functions most efficiently. Furthermore, we showed that Ca(2+) -mediated induction of AMP-activated protein kinase (AMPK) phosphorylation was blocked by SOC inhibition. Our identification of important regulators of Ca(2+) signaling in avian sperm suggests that SOCs play a predominant role in gamete function, whereas T-type channels may not be involved. In addition, Ca(2+) entry via SOCs appears to be the most likely pathway for AMPK activation and energy-requiring sperm functions such as motility and the acrosome reaction.


Assuntos
Reação Acrossômica/fisiologia , Canais de Cálcio/fisiologia , Motilidade dos Espermatozoides/fisiologia , Adenilato Quinase/metabolismo , Animais , Cálcio/metabolismo , Galinhas , Masculino
12.
PLoS One ; 11(1): e0147559, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26808520

RESUMO

Sperm require high levels of energy to ensure motility and acrosome reaction (AR) accomplishment. The AMP-activated protein kinase (AMPK) has been demonstrated to be strongly involved in the control of these properties. We address here the question of the potential role of calcium mobilization on AMPK activation and function in chicken sperm through the Ca(2+)/calmodulin-dependent protein kinase kinases (CaMKKs) mediated pathway. The presence of CaMKKs and their substrates CaMKI and CaMKIV was evaluated by western-blotting and indirect immunofluorescence. Sperm were incubated in presence or absence of extracellular Ca(2+), or of CaMKKs inhibitor (STO-609). Phosphorylations of AMPK, CaMKI, and CaMKIV, as well as sperm functions were evaluated. We demonstrate the presence of both CaMKKs (α and ß), CaMKI and CaMKIV in chicken sperm. CaMKKα and CaMKI were localized in the acrosome, the midpiece, and at much lower fluorescence in the flagellum, whereas CaMKKß was mostly localized in the flagellum and much less in the midpiece and the acrosome. CaMKIV was only present in the flagellum. The presence of extracellular calcium induced an increase in kinases phosphorylation and sperm activity. STO-609 reduced AMPK phosphorylation in the presence of extracellular Ca(2+) but not in its absence. STO-609 did not affect CaMKIV phosphorylation but decreased CaMKI phosphorylation and this inhibition was quicker in the presence of extracellular Ca(2+) than in its absence. STO-609 efficiently inhibited sperm motility and AR, both in the presence and absence of extracellular Ca(2+). Our results show for the first time the presence of CaMKKs (α and ß) and one of its substrate, CaMKI in different subcellular compartments in germ cells, as well as the changes in the AMPK regulation pathway, sperm motility and AR related to Ca(2+) entry in sperm through the Ca(2+)/CaM/CaMKKs/CaMKI pathway. The Ca(2+)/CaMKKs/AMPK pathway is activated only under conditions of extracellular Ca(2+) entry in the cells.


Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Quinase da Proteína Quinase Dependente de Cálcio-Calmodulina/metabolismo , Espermatozoides/fisiologia , Reação Acrossômica , Animais , Benzimidazóis/farmacologia , Quinase da Proteína Quinase Dependente de Cálcio-Calmodulina/antagonistas & inibidores , Galinhas , Masculino , Naftalimidas/farmacologia , Fosforilação , Inibidores de Proteínas Quinases/farmacologia , Motilidade dos Espermatozoides , Especificidade por Substrato
13.
Endocrinology ; 157(1): 304-22, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26562259

RESUMO

Episodic release of GnRH is essential for reproductive function. In vitro studies have established that this episodic release is an endogenous property of GnRH neurons and that GnRH secretory pulses are associated with synchronization of GnRH neuron activity. The cellular mechanisms by which GnRH neurons synchronize remain largely unknown. There is no clear evidence of physical coupling of GnRH neurons through gap junctions to explain episodic synchronization. However, coupling of glial cells through gap junctions has been shown to regulate neuron activity in their microenvironment. The present study investigated whether glial cell communication through gap junctions plays a role in GnRH neuron activity and secretion in the mouse. Our findings show that Glial Fibrillary Acidic Protein-expressing glial cells located in the median eminence in close vicinity to GnRH fibers expressed Gja1 encoding connexin-43. To study the impact of glial-gap junction coupling on GnRH neuron activity, an in vitro model of primary cultures from mouse embryo nasal placodes was used. In this model, GnRH neurons possess a glial microenvironment and were able to release GnRH in an episodic manner. Our findings show that in vitro glial cells forming the microenvironment of GnRH neurons expressed connexin-43 and displayed functional gap junctions. Pharmacological blockade of the gap junctions with 50 µM 18-α-glycyrrhetinic acid decreased GnRH secretion by reducing pulse frequency and amplitude, suppressed neuronal synchronization and drastically reduced spontaneous electrical activity, all these effects were reversed upon 18-α-glycyrrhetinic acid washout.


Assuntos
Junções Comunicantes/metabolismo , Hormônio Liberador de Gonadotropina/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Neuroglia/metabolismo , Mucosa Olfatória/metabolismo , Células Receptoras Sensoriais/metabolismo , Animais , Biomarcadores/metabolismo , Células Cultivadas , Conexina 43/genética , Conexina 43/metabolismo , Embrião de Mamíferos/citologia , Inibidores Enzimáticos/farmacologia , Junções Comunicantes/efeitos dos fármacos , Junções Comunicantes/ultraestrutura , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Proteína Glial Fibrilar Ácida/genética , Proteína Glial Fibrilar Ácida/metabolismo , Hormônio Liberador de Gonadotropina/genética , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Humanos , Cinética , Eminência Mediana/citologia , Eminência Mediana/efeitos dos fármacos , Eminência Mediana/metabolismo , Camundongos Transgênicos , Proteínas do Tecido Nervoso/antagonistas & inibidores , Proteínas do Tecido Nervoso/genética , Neuroglia/efeitos dos fármacos , Neuroglia/ultraestrutura , Neurotoxinas/farmacologia , Mucosa Olfatória/efeitos dos fármacos , Mucosa Olfatória/ultraestrutura , Proteínas Recombinantes de Fusão/metabolismo , Células Receptoras Sensoriais/efeitos dos fármacos , Células Receptoras Sensoriais/ultraestrutura , Técnicas de Cultura de Tecidos
14.
Front Neurosci ; 9: 463, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26696819

RESUMO

During development, environmental estrogens are able to induce an estrogen mimetic action that may interfere with endocrine and neuroendocrine systems. The present study investigated the effects on the reproductive function in female mice following developmental exposure to pharmaceutical ethinylestradiol (EE2), the most widespread and potent synthetic steroid present in aquatic environments. EE2 was administrated in drinking water at environmentally relevant (ENVIR) or pharmacological (PHARMACO) doses [0.1 and 1 µg/kg (body weight)/day respectively], from embryonic day 10 until postnatal day 40. Our results show that both groups of EE2-exposed females had advanced vaginal opening and shorter estrus cycles, but a normal fertility rate compared to CONTROL females. The hypothalamic population of GnRH neurons was affected by EE2 exposure with a significant increase in the number of perikarya in the preoptic area of the PHARMACO group and a modification in their distribution in the ENVIR group, both associated with a marked decrease in GnRH fibers immunoreactivity in the median eminence. In EE2-exposed females, behavioral tests highlighted a disturbed maternal behavior, a higher lordosis response, a lack of discrimination between gonad-intact and castrated males in sexually experienced females, and an increased anxiety-related behavior. Altogether, these results put emphasis on the high sensitivity of sexually dimorphic behaviors and neuroendocrine circuits to disruptive effects of EDCs.

15.
Sci Rep ; 5: 17457, 2015 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-26640081

RESUMO

Reproductive behavior and physiology in adulthood are controlled by hypothalamic sexually dimorphic neuronal networks which are organized under hormonal control during development. These organizing effects may be disturbed by endocrine disrupting chemicals (EDCs). To determine whether developmental exposure to Ethinylestradiol (EE2) may alter reproductive parameters in adult male mice and their progeny, Swiss mice (F1 generation) were exposed from prenatal to peripubertal periods to EE2 (0.1-1 µg/kg/d). Sexual behavior and reproductive physiology were evaluated on F1 males and their F2, F3 and F4 progeny. EE2-exposed F1 males and their F2 to F4 progeny exhibited EE2 dose-dependent increased sexual behavior, with reduced latencies of first mount and intromission, and higher frequencies of intromissions with a receptive female. The EE2 1 µg/kg/d exposed animals and their progeny had more calbindin immunoreactive cells in the medial preoptic area, known to be involved in the control of male sexual behavior in rodents. Despite neuroanatomical modifications in the Gonadotropin-Releasing Hormone neuron population of F1 males exposed to both doses of EE2, no major deleterious effects on reproductive physiology were detected. Therefore EE2 exposure during development may induce a hypermasculinization of the brain, illustrating how widespread exposure of animals and humans to EDCs can impact health and behaviors.


Assuntos
Etinilestradiol/farmacologia , Sistemas Neurossecretores/efeitos dos fármacos , Comportamento Sexual Animal/efeitos dos fármacos , Animais , Calbindinas/metabolismo , Feminino , Fertilidade/efeitos dos fármacos , Genitália/efeitos dos fármacos , Hormônio Liberador de Gonadotropina/metabolismo , Hipotálamo/efeitos dos fármacos , Hipotálamo/metabolismo , Kisspeptinas/metabolismo , Masculino , Camundongos , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Reprodução/efeitos dos fármacos , Testosterona/sangue
16.
Glia ; 61(4): 550-66, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23404564

RESUMO

During development, GnRH-1 neurons differentiate extracerebraly from the nasal placode and migrate from the vomeronasal organ to the forebrain along vomeronasal and terminal nerves. Numerous studies have described the influence of different molecules on the migration of GnRH-1 neurons, however, the role of microenvironment cells remains poorly understood. This study used GFAP-GFP transgenic mice to detect glial cells at early developmental stages. Using nasal explant cultures, the comigration of glial cells with GnRH-1 neurons was clearly demonstrated. This in vitro approach showed that glial cells began migrating from the explants before GnRH-1 neurons. They remained ahead of the GnRH-1 migratory front and stopped migrating after the GnRH-1 neurons. The association of these glial cells with the axons combined with gene expression analysis of GFAP-GFP sorted cells enabled them to be identified as olfactory ensheathing cells (OEC). Immunohistochemical analysis revealed the presence of multiple glial cell-type markers showing several OEC subpopulations surrounding GnRH-1 neurons. Moreover, these OEC expressed genes whose products are involved in the migration of GnRH-1 neurons, such as Nelf and Semaphorin 4. In situ data confirmed that the majority of the GnRH-1 neurons were associated with glial cells along the vomeronasal axons in nasal septum and terminal nerves in the nasal forebrain junction as early as E12.5. Overall, these data demonstrate an OEC microenvironment for migrating GnRH-1 neurons during mouse development. The fact that this glial cell type precedes GnRH-1 neurons and encodes for molecules involved in their nasal migration suggests that it participates in the GnRH-1 system ontogenesis.


Assuntos
Movimento Celular/fisiologia , Microambiente Celular/fisiologia , Hormônio Liberador de Gonadotropina/fisiologia , Bulbo Olfatório/citologia , Bulbo Olfatório/embriologia , Mucosa Olfatória/citologia , Mucosa Olfatória/embriologia , Precursores de Proteínas/fisiologia , Animais , Células Cultivadas , Proteína Glial Fibrilar Ácida , Camundongos , Camundongos Transgênicos , Proteínas do Tecido Nervoso/genética , Bulbo Olfatório/metabolismo , Mucosa Olfatória/metabolismo , Técnicas de Cultura de Órgãos , Regiões Promotoras Genéticas/genética , Coelhos
17.
Biochem Biophys Res Commun ; 420(2): 247-52, 2012 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-22405825

RESUMO

Lim kinase 2 isoforms, LIMK2a and LIMK2b, phosphorylate cofilin leading to remodeling of actin cytoskeleton during neuronal differentiation. The expression and function of the LIMK2d isoform, missing the kinase domain, remain unknown. We analyzed the expression of LIMK2 splice variants in adult rat brain and in cultures of rat neural stem cells by RT-QPCR. All three splice variants were expressed in adult cortex, hippocampus and cerebellum. Limk2a and Limk2d expression, but not Limk2b, increased during neuronal differentiation. We studied the localization and function of LIMK2d isoform by transfecting Hela, NSC-34, and hippocampal rat neuron cultures. Similarly to LIMK2b, LIMK2d was expressed in the cytoplasm, neurites and dendritic spines, but not in the nucleus. Similarly to LIMK2a, LIMK2d over-expression in NSC-34 cells increased neurite length, but independently of cofilin phosphorylation or of direct interaction with actin. Overall, these results indicate that LIMK2d is a third LIMK2 isoform which regulates neurite extension and highlights the possible existence of a kinase independent function of LIMK2.


Assuntos
Quinases Lim/metabolismo , Neuritos/fisiologia , Actinas/metabolismo , Animais , Células Cultivadas , Cerebelo/enzimologia , Hipocampo/enzimologia , Isoenzimas/genética , Isoenzimas/metabolismo , Quinases Lim/genética , Camundongos , Neuritos/enzimologia , Estrutura Terciária de Proteína , Ratos
18.
Brain Res ; 1433: 29-37, 2012 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-22154466

RESUMO

To evaluate the potentially disrupting effects of environmental estrogens on neuroendocrine networks controlling reproduction, we studied the impact of the pharmaceutical product 17-α-ethinylestradiol (EE2) on gonadotropin-releasing hormone (GnRH-1) neuron development in mouse embryo. Pregnant mice were treated per os with EE2 at 0.01, 0.1 or 1 µg/kg/day, between embryonic days 10.5 (E10.5) and E13.5, a period during which GnRH-1 neurons are generated and start their intra-nasal migration. Embryos at E13.5 were examined and processed for GnRH-1 immunohistochemistry. Immunopositive neurons were counted all along their migratory path. A short oral administration of environmentally relevant doses of EE2 to pregnant mice had a significant impact on whole embryo development, leading to a limited but significant growth retardation. The total number of GnRH-1 neurons was statistically significantly increased in a dose-dependent manner. The repartition of GnRH-1 neurons along their migratory path was not affected by EE2 treatment. These results suggest an impact of environmental EE2 concentrations on embryonic GnRH-1 development through a modulation of neurogenesis and/or apoptosis.


Assuntos
Desenvolvimento Embrionário/efeitos dos fármacos , Etinilestradiol/toxicidade , Hormônio Liberador de Gonadotropina/metabolismo , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Precursores de Proteínas/metabolismo , Animais , Proliferação de Células/efeitos dos fármacos , Desenvolvimento Embrionário/fisiologia , Feminino , Retardo do Crescimento Fetal/induzido quimicamente , Retardo do Crescimento Fetal/metabolismo , Retardo do Crescimento Fetal/patologia , Exposição Materna/efeitos adversos , Camundongos , Neurônios/patologia , Gravidez
19.
Eur J Neurosci ; 32(12): 2031-41, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21143658

RESUMO

The neurohormone gonadotropin-releasing hormone (GnRH) is critical for all the aspects of reproductive life in vertebrates. GnRH is secreted by a small number of neurons dispersed within the preoptic-hypothalamic region. These neurons are derived from the embryonic olfactory pit. They then migrate along olfactory, vomeronasal and terminal nerves to their final destination. Classical approaches to study the regulation of GnRH secretion during the reproductive cycle have focused on the various neuronal inputs on GnRH neurons and their regulation by ovarian steroids. However, it is well known that steroids will change the microenvironment of neuronal networks and can induce plasticity and functional changes. In this review, we will focus on the intimate relationship of developing and adult GnRH neurons with the polysialylated form of neural cell adhesion molecule (PSA-NCAM), a major molecular actor in the morphogenesis and adult plasticity of the nervous system. We will first recapitulate the spatiotemporal relationship between PSA-NCAM and migrating GnRH neurons during embryogenesis of various vertebrate species and discuss its importance for GnRH neuron development as shown by various loss of function studies. In the adult, we will review the relationships between PSA-NCAM and GnRH neurons across various physiological states, and open the discussion to the use of new model systems that can help to unravel the function and mechanism of action of PSA-NCAM on GnRH neuronal network activity and GnRH release.


Assuntos
Hormônio Liberador de Gonadotropina/metabolismo , Molécula L1 de Adesão de Célula Nervosa/metabolismo , Plasticidade Neuronal/fisiologia , Neurônios/fisiologia , Ácidos Siálicos/metabolismo , Animais , Movimento Celular , Humanos , Hipotálamo/anatomia & histologia , Hipotálamo/crescimento & desenvolvimento , Hipotálamo/fisiologia , Modelos Neurológicos , Neurônios/citologia
20.
Eur J Neurosci ; 32(12): 2042-52, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21143659

RESUMO

In adult mammalian brain, two main germinative regions located in the subventricular zone of the lateral ventricle and in the subgranular cell layer of the hippocampal dentate gyrus have been considerably documented and are still under intense scrutiny. However, new neuron formation has recently been reported in various other brain areas including the hypothalamus. This central structure, responsible for the control of many major neuroendocrine functions such as reproduction, expresses high levels of PSA-NCAM and nestin, both proteins being involved in structural and morphological plasticity mechanisms. Cell proliferation and new neuron production have been demonstrated in the adult hypothalamus of numerous species, although not hitherto described in non-human primates and humans. Similarly to the subventricular zone and in the subgranular cell layer, the adult hypothalamic neurogenesis process is subject to dynamic regulation by various physiological and pharmacological signals. Several pieces of evidence support the hypothesis that a stem cell niche-like architecture exist in the hypothalamus region lining the third ventricle thereby enabling adult neural stem cells to continuously generate neurons in vivo throughout life. Furthermore, recent data indicating that new hypothalamic neurons may become functionally implicated in sensory information processing endorse the assumption that the hypothalamus might be a neurogenic region.


Assuntos
Encéfalo/anatomia & histologia , Encéfalo/fisiologia , Hipotálamo/citologia , Hipotálamo/fisiologia , Neurogênese/fisiologia , Terceiro Ventrículo/citologia , Terceiro Ventrículo/fisiologia , Animais , Biomarcadores/metabolismo , Proliferação de Células , Humanos , Plasticidade Neuronal/fisiologia , Nicho de Células-Tronco
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