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Maytalman E, Nemutlu Samur D. Neuroendocrine modulation by metamizole and indomethacin: investigating the impact on neuronal markers and GnRH release. Endocrine 2024; 85:1327-1336. [PMID: 38625503 DOI: 10.1007/s12020-024-03822-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 04/02/2024] [Indexed: 04/17/2024]
Abstract
PURPOSE Some evidence that non-steroidal anti-inflammatory drugs have neuroprotective effects indicates their potential for use in a new field. However, their effects on hormone secretion have yet to be adequately discovered. Therefore, we aimed to evaluate the effects of metamizole and indomethacin on neuronal markers as well as the GnRH expression in the GT1-7 cell line. METHODS The effects of these drugs on proliferation were evaluated by MTT analysis. The effect of 10-50-250 µM concentrations of the drugs also on the expression of neuronal factors and markers, including NGF, nestin and βIII Tubulin, and additionally GnRH, was determined by the RT-qPCR method. RESULTS NGF and nestin mRNA expressions were increased in all concentrations of both metamizole and indomethacin. No changes were detected in βIII Tubulin. While metamizole showed an increase in GnRH mRNA expression, there was no change at 10 and 50 µM concentrations of indomethacin, but a remarkable decrease was observed at 250 µM concentrations. CONCLUSIONS The results of our study showing an increase in the expression of neuronal factors reveal that metamizole and indomethacin may have possible neuroprotective effects. Moreover, the effects on the GnRH expression appear to be different. Animal models are required to confirm these effects of NSAIDs on neurons.
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Affiliation(s)
- Erkan Maytalman
- Department of Pharmacology, School of Medicine, Alanya Alaaddin Keykubat University, Antalya, Turkey.
| | - Dilara Nemutlu Samur
- Department of Pharmacology, School of Medicine, Alanya Alaaddin Keykubat University, Antalya, Turkey
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2
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Messi E, Pimpinelli F, Andrè V, Rigobello C, Gotti C, Maggi R. The alpha-7 nicotinic acetylcholine receptor is involved in a direct inhibitory effect of nicotine on GnRH release: In vitro studies. Mol Cell Endocrinol 2018; 460:209-218. [PMID: 28754351 DOI: 10.1016/j.mce.2017.07.025] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Revised: 07/04/2017] [Accepted: 07/24/2017] [Indexed: 12/28/2022]
Abstract
The activation of nicotinic cholinergic receptors (nAChR) inhibits the reproductive axis; however, it is not clear whether nicotine may directly modulate the release of hypothalamic gonadotropin-releasing hormone (GnRH). Experiments carried out in GT1-1 immortalized GnRH neurons reveal the presence of a single class of high affinity α4β2 and α7 nAchR subtypes. The exposure of GT1-1 cells to nicotine does not modify the basal accumulation of GnRH. However, nicotine was found to modify GnRH pulsatility in perifusion experiments and inhibits, the release of GnRH induced by prostaglandin E1 or by K+-induced cell depolarization; these effects were reversed by D-tubocurarine and α-bungarotoxin. In conclusion, the results reported here indicate that: functional nAChRs are present on GT1-1 cells, the activation of the α-bungarotoxin-sensitive subclass (α7) produces an inhibitory effect on the release of GnRH and that the direct action of nicotine on GnRH neurons may be involved in reducing fertility of smokers.
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Affiliation(s)
- Elio Messi
- Dept. of Pharmacological and Biomedical Sciences, Università Degli Studi di Milano, Milan, Italy
| | - Federica Pimpinelli
- Dept. of Pharmacological and Biomedical Sciences, Università Degli Studi di Milano, Milan, Italy
| | - Valentina Andrè
- Dept. of Pharmacological and Biomedical Sciences, Università Degli Studi di Milano, Milan, Italy
| | - Chiara Rigobello
- Dept. of Pharmacological and Biomedical Sciences, Università Degli Studi di Milano, Milan, Italy
| | - Cecilia Gotti
- CNR, Neuroscience Institute-Milano, Biometra University of Milan, Milan, Italy
| | - Roberto Maggi
- Dept. of Pharmacological and Biomedical Sciences, Università Degli Studi di Milano, Milan, Italy.
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3
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Antoniotti S, Ruffinatti FA, Torriano S, Luganini A, D'Alessandro R, Lovisolo D. REST levels affect the functional expression of voltage dependent calcium channels and the migratory activity in immortalized GnRH neurons. Neurosci Lett 2016; 629:19-25. [PMID: 27349310 DOI: 10.1016/j.neulet.2016.06.050] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 06/23/2016] [Indexed: 12/27/2022]
Abstract
The repressor element-1 silencing transcription factor (REST) has emerged as a key controller of neuronal differentiation and has been shown to play a critical role in the expression of the neuronal phenotype; however, much has still to be learned about its role at specific developmental stages and about the functional targets affected. Among these targets, calcium signaling mechanisms are critically dependent on the developmental stage and their full expression is a hallmark of the mature, functional neuron. We have analyzed the role played by REST in GN11 cells, an immortalized cell line derived from gonadotropin hormone releasing hormone (GnRH) neurons at an early developmental stage, electrically non-excitable and with a strong migratory activity. We show for the first time that functional voltage-dependent calcium channels are expressed in wild type GN11 cells; down-regulation of REST by a silencing approach shifts these cells towards a more differentiated phenotype, increasing the functional expression of P/Q-type channels and reducing their migratory potential.
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Affiliation(s)
- Susanna Antoniotti
- Department of Life Sciences and Systems Biology, University of Torino, via Accademia Albertina 13, 10123, Torino, Italy; NIS Centre for Nanostructured Interfaces and Surfaces, University of Torino, Italy
| | | | - Simona Torriano
- Department of Life Sciences and Systems Biology, University of Torino, via Accademia Albertina 13, 10123, Torino, Italy
| | - Anna Luganini
- Department of Life Sciences and Systems Biology, University of Torino, via Accademia Albertina 13, 10123, Torino, Italy
| | - Rosalba D'Alessandro
- National Institute for Digestive Diseases De Bellis, via Turi 27, 70013, Castellana Grotte, Bari, Italy
| | - Davide Lovisolo
- Department of Life Sciences and Systems Biology, University of Torino, via Accademia Albertina 13, 10123, Torino, Italy; NIS Centre for Nanostructured Interfaces and Surfaces, University of Torino, Italy; Neuroscience Institute of Torino, Italy.
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4
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Howard SR, Guasti L, Ruiz-Babot G, Mancini A, David A, Storr HL, Metherell LA, Sternberg MJ, Cabrera CP, Warren HR, Barnes MR, Quinton R, de Roux N, Young J, Guiochon-Mantel A, Wehkalampi K, André V, Gothilf Y, Cariboni A, Dunkel L. IGSF10 mutations dysregulate gonadotropin-releasing hormone neuronal migration resulting in delayed puberty. EMBO Mol Med 2016; 8:626-42. [PMID: 27137492 PMCID: PMC4888853 DOI: 10.15252/emmm.201606250] [Citation(s) in RCA: 87] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Early or late pubertal onset affects up to 5% of adolescents and is associated with adverse health and psychosocial outcomes. Self‐limited delayed puberty (DP) segregates predominantly in an autosomal dominant pattern, but the underlying genetic background is unknown. Using exome and candidate gene sequencing, we have identified rare mutations in IGSF10 in 6 unrelated families, which resulted in intracellular retention with failure in the secretion of mutant proteins. IGSF10 mRNA was strongly expressed in embryonic nasal mesenchyme, during gonadotropin‐releasing hormone (GnRH) neuronal migration to the hypothalamus. IGSF10 knockdown caused a reduced migration of immature GnRH neurons in vitro, and perturbed migration and extension of GnRH neurons in a gnrh3:EGFP zebrafish model. Additionally, loss‐of‐function mutations in IGSF10 were identified in hypothalamic amenorrhea patients. Our evidence strongly suggests that mutations in IGSF10 cause DP in humans, and points to a common genetic basis for conditions of functional hypogonadotropic hypogonadism (HH). While dysregulation of GnRH neuronal migration is known to cause permanent HH, this is the first time that this has been demonstrated as a causal mechanism in DP.‡
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Affiliation(s)
- Sasha R Howard
- Centre for Endocrinology, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Leonardo Guasti
- Centre for Endocrinology, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Gerard Ruiz-Babot
- Centre for Endocrinology, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Alessandra Mancini
- Centre for Endocrinology, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Alessia David
- Centre for Integrative Systems Biology and Bioinformatics, Department of Life Sciences, Imperial College London, London, UK
| | - Helen L Storr
- Centre for Endocrinology, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Lousie A Metherell
- Centre for Endocrinology, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Michael Je Sternberg
- Centre for Integrative Systems Biology and Bioinformatics, Department of Life Sciences, Imperial College London, London, UK
| | - Claudia P Cabrera
- Centre for Translational Bioinformatics, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK NIHR Barts Cardiovascular Biomedical Research Unit, Queen Mary University of London, London, UK
| | - Helen R Warren
- NIHR Barts Cardiovascular Biomedical Research Unit, Queen Mary University of London, London, UK Department of Clinical Pharmacology, William Harvey Research Institute, Barts and The London School of Medicine, Queen Mary University of London, London, UK
| | - Michael R Barnes
- Centre for Translational Bioinformatics, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK NIHR Barts Cardiovascular Biomedical Research Unit, Queen Mary University of London, London, UK
| | - Richard Quinton
- Institute of Genetic Medicine University of Newcastle-upon-Tyne, Newcastle-upon-Tyne, UK
| | - Nicolas de Roux
- Unité Mixte de Recherche 1141, Institut National de la Santé et de la Recherche Médicale, Paris, France Université Paris Diderot, Sorbonne Paris Cité, Hôpital Robert Debré, Paris, France Laboratoire de Biochimie, Assistance Publique-Hôpitaux de Paris, Hôpital Robert Debré, Paris, France
| | - Jacques Young
- Univ Paris-Sud, Le Kremlin Bicêtre, France INSERM UMR-1185, Le Kremlin Bicêtre, France Assistance Publique-Hôpitaux de Paris, Bicêtre Hospital, Le Kremlin-Bicêtre, France Department of Reproductive Endocrinology, Bicêtre Hospital, Le Kremlin-Bicêtre, France
| | - Anne Guiochon-Mantel
- Univ Paris-Sud, Le Kremlin Bicêtre, France INSERM UMR-1185, Le Kremlin Bicêtre, France Assistance Publique-Hôpitaux de Paris, Bicêtre Hospital, Le Kremlin-Bicêtre, France
| | - Karoliina Wehkalampi
- Children's Hospital, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | - Valentina André
- Department of Pharmacological and Biomolecular Sciences, University of Milan, Milan, Italy
| | - Yoav Gothilf
- Department of Neurobiology, The George S. Wise Faculty of Life Sciences and Sagol School of Neuroscience, Tel-Aviv University, Tel Aviv, Israel
| | - Anna Cariboni
- Department of Pharmacological and Biomolecular Sciences, University of Milan, Milan, Italy Institute of Ophthalmology, University College London (UCL), London, UK
| | - Leo Dunkel
- Centre for Endocrinology, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK
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5
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Interaction of SiO2 nanoparticles with neuronal cells: Ionic mechanisms involved in the perturbation of calcium homeostasis. Int J Biochem Cell Biol 2015. [DOI: 10.1016/j.biocel.2015.07.012] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Larco DO, Cho-Clark M, Mani SK, Wu TJ. The metabolite GnRH-(1-5) inhibits the migration of immortalized GnRH neurons. Endocrinology 2013; 154:783-95. [PMID: 23321696 DOI: 10.1210/en.2012-1746] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The decapeptide GnRH is an important regulator of reproductive behavior and function. In the extracellular matrix, GnRH is metabolized by the endopeptidase EC3.4.24.15 (EP24.15) to generate the pentapeptide GnRH-(1-5). In addition to its expression in the adult hypothalamus, EP24.15 is expressed along the migratory path of GnRH-expressing neurons during development. Although we have previously demonstrated a role for EP24.15 in the generation of the biologically active pentapeptide GnRH-(1-5) in regulating GnRH expression and mediating sexual behavior during adulthood in rodents, the modulatory role of GnRH-(1-5) in the migration of GnRH neurons during development remains unknown. To address this information gap, we examined the effect of GnRH-(1-5) on the cellular migration of a premigratory GnRH-secreting neuronal cell line, the GN11 cell, using a wound-healing assay. Dose- and time-response studies demonstrated that GnRH-(1-5) significantly delayed wound closure. We then sought to identify the mechanism by which GnRH-(1-5) inhibits migration. Because the cognate GnRH receptor is a G protein-coupled receptor, we examined whether GnRH-(1-5) regulates migration by also activating a G protein-coupled receptor. Using a high-throughput β-arrestin recruitment assay, we identified an orphan G protein-coupled receptor (GPR173) that was specifically activated by GnRH-(1-5). Interestingly, small interfering RNA to GPR173 reversed the GnRH-(1-5)-mediated inhibition on migration of GN11 neurons. Furthermore, we also demonstrate that the GnRH-(1-5)-activated GPR173-dependent signal transduction pathway involves the activation of the signal transducer and activator of transcription 3 in GnRH migration. These findings indicate a potential regulatory role for GnRH-(1-5) in GnRH neuronal migration during development.
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Affiliation(s)
- Darwin O Larco
- Program in Molecular and Cellular Biology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
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7
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Zito A, Cartelli D, Cappelletti G, Cariboni A, Andrews W, Parnavelas J, Poletti A, Galbiati M. Neuritin 1 promotes neuronal migration. Brain Struct Funct 2012; 219:105-18. [DOI: 10.1007/s00429-012-0487-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Accepted: 11/16/2012] [Indexed: 11/30/2022]
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8
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Ruscica M, Dozio E, Steffani L, Passafaro L, Mazzer M, Castellano JM, Motta M, Tena-Sempere M, Magni P. Role of the energy sensor adenosine monophosphate-activated protein kinase in the regulation of immature gonadotropin-releasing hormone neuron migration. J Endocrinol Invest 2011; 34:e362-8. [PMID: 21697647 DOI: 10.3275/7803] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
BACKGROUND The 5'-AMP-activated protein kinase (AMPK) plays a fundamental role in regulating energy homeostasis as well as feeding and metabolism, through central and peripheral actions. AMPK is activated by conditions causing ATP depletion and by different metabolic molecules, such as adiponectin and AMPK agonist, such as 5-aminoimidazole- 4-carboxamide-1-β-D-ribofuranoside (AICAR). AMPK activation has also been shown to affect the migration of different cell types and to participate in the central control of reproductive function, although information concerning AMPK and the development of the hypothalamic reproductive compartment is lacking. AIM To explore whether AMPK activation by globular adiponectin (gAdipo) and AICAR may affect the migratory ability of GnRH neurons. MATERIALS AND METHODS We used GN11 immature GnRH neurons (in vitro model system), RT-PCR and Western blot analysis, and Boyden's chamber assay. RESULTS gAdipo did not affect FBS-stimulated migration of GN11 cells and activated AMPK through the mandatory phosphorylation of extracellular signal-regulated kinase 1 and 2 (ERK1/2) and Akt, which also interact one to each other. AICAR treatment inhibited FBS-stimulated GN11 cell migration, through a long-lasting activation of AMPK. A downstream activation of ERK1/2 by AICAR was also observed and inhibition of ERK1/2 amplified AICAR-induced inhibition of migration. CONCLUSIONS The direct, but not the indirect, activation of AMPK appears to negatively affect FBSinduced GN11 cell migration, suggesting that the final balance between pro-migratory and anti-migratory actions may also depend upon the specific sequence of intracellular signals activated by one agent.
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Affiliation(s)
- M Ruscica
- Department of Endocrinology, Pathophysiology and Applied Biology, Inter-University Center for Research on Reproductive Health (CIRMAR), Center of Excellence on Neurodegenerative Diseases (CEND), Città Studi University of Milan, Via G. Balzaretti 9, 20133 Milan, Italy
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9
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Ariano P, Dalmazzo S, Owsianik G, Nilius B, Lovisolo D. TRPC channels are involved in calcium-dependent migration and proliferation in immortalized GnRH neurons. Cell Calcium 2011; 49:387-94. [PMID: 21511334 DOI: 10.1016/j.ceca.2011.03.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2010] [Revised: 03/03/2011] [Accepted: 03/22/2011] [Indexed: 11/19/2022]
Abstract
Gonadotropin-releasing hormone (GnRH)-secreting neurons are key regulators of the reproductive behaviour in vertebrates. These neurons show a peculiar migratory pattern during embryonic development, and its perturbations have profound impact on fertility and other related functional aspects. Changes in the intracellular calcium concentration, [Ca(2+)](i), induced by different extracellular signals, play a central role in the control of neuronal migration, but the available knowledge regarding GnRH neurons is still limited. Our goal was to investigate mechanisms that may be involved in the Ca(2+) dependence of the migratory behaviour in these neurons. We focused on the "classical" Transient Receptor Potential (TRPC) subfamily of Ca(2+)-permeable cation channels, recently shown to be involved in other aspects of neuronal development. Using GN11 cells, immortalized early stage GnRH neurons, we set to investigate Ca(2+) signals under basal conditions and in the presence of a well-established motogen, fetal calf serum (FCS), and the effect of pharmacological TRPC agonists and antagonists on Ca(2+) oscillations, cell motility and proliferation. We have found that a subpopulation of GN11 cells shows spontaneous Ca(2+) transients and that this activity is increased in the presence of serum. Quantitative real-time PCR showed that transcripts of some TRPC members are expressed in GN11 cells. Interestingly, pharmacological experiments with inhibitors, SKF-96365, lanthanum, anti-TRPC1 antibody, and activators, 1-oleil 2-acetyl-sn-glycerol, of TRPCs suggested that the activation of these channels can account for both the basal Ca(2+) oscillations and the increased activity in the presence of FCS. Moreover, functional studies using the same pharmacological tools supported their involvement in the control of motility and proliferation. Thus, our data provide evidence for the involvement of Ca(2+)-permeable channels of the TRPC subfamily in the control of functional properties of neurosecretory cells and neuronal motility.
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Affiliation(s)
- Paolo Ariano
- Department of Animal and Human Biology, University of Torino, Italy
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10
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Iyer AK, Brayman MJ, Mellon PL. Dynamic chromatin modifications control GnRH gene expression during neuronal differentiation and protein kinase C signal transduction. Mol Endocrinol 2011; 25:460-73. [PMID: 21239613 DOI: 10.1210/me.2010-0403] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
GnRH, a neuropeptide produced by rare, specialized hypothalamic secretory neurons, is critical for reproduction. During development, GnRH gene expression increases as neurons migrate from the olfactory placode to the hypothalamus, with highest levels in the mature, postmitotic state. While neuronal differentiation is known to be controlled by chromatin modulations, the role of chromatin dynamics in GnRH gene regulation has not been studied. Here, we use mature and immature GnRH neuronal cell models to show that both neuron-specific and protein kinase C regulation of GnRH expression are mediated by chromatin structure and histone modifications. Only in GT1-7 mature GnRH neuronal cells did GnRH regulatory elements display high sensitivity to DNase and enrichment of active histone markers histone-H3 acetylation and H3 lysine 4 trimethylation (H3K4-Me3), as well as RNA polymerase II (RNAPII) binding and enhancer RNA transcription. In contrast, H3K9-Me2, a marker of inactive chromatin, was highest in nonneuronal cells, low in GT1-7 cells, and intermediate in immature GnRH neuronal cells. The chromatin of the GnRH gene was therefore active in mature GnRH neuronal cells, inactive in nonneuronal cells, but not fully inactive in immature GnRH neuronal cells. Activation of protein kinase C (PKC) potently represses GnRH expression. PKC activation caused closing of the chromatin and decreased RNAPII occupancy at the GnRH minimal promoter (-278/-97). At GnRH-Enhancer-1 (-2404/-2100), PKC activation decreased phosphorylated-RNAPII binding, enhancer RNA transcription, and H3 acetylation, and reciprocally increased H3K9-Me2. Chromatin modifications therefore participate in the dynamic regulation and specification of GnRH expression to differentiated hypothalamic neurons.
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Affiliation(s)
- Anita K Iyer
- Department of Reproductive Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0674, USA
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11
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Ramakrishnan S, Lee W, Navarre S, Kozlowski DJ, Wayne NL. Acquisition of spontaneous electrical activity during embryonic development of gonadotropin-releasing hormone-3 neurons located in the terminal nerve of transgenic zebrafish (Danio rerio). Gen Comp Endocrinol 2010; 168:401-7. [PMID: 20515692 PMCID: PMC2922451 DOI: 10.1016/j.ygcen.2010.05.009] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2010] [Accepted: 05/23/2010] [Indexed: 11/23/2022]
Abstract
There are multiple populations of gonadotropin-releasing hormone (GnRH) neurons that have distinct physiological and behavioral functions. Teleost fish have a population of GnRH3 neurons located in the terminal nerve (TN) associated with the olfactory bulb that is thought to play a neuromodulatory role in multiple physiological systems, including olfactory, visual, and reproductive. We used transgenic zebrafish in which the GnRH3 promoter drives expression of a green fluorescent protein to identify GnRH3 neurons during development in live embryos. Unlike with hypophysiotropic GnRH neurons of zebrafish, TN-GnRH3 neurons are of neural crest origin and are one of the first populations of GnRH neurons to develop in the early embryo. Using a combination of optical imaging and electrophysiology, we showed that during the first 3 days post-fertilization, TN-GnRH3 neurons increase in number, extend neural projections, move in association with tissue expansion, and acquire an adult-pattern of spontaneous action potential firing. Early during development, about half of the neurons were quiescent/non-firing. Later, at 3 days post-fertilization, there was an increase in the proportion of neurons showing action potential firing and an increase in the number of neurons that showed an adult-like tonic or beating pattern of action potential firing with a firing frequency similar to that seen in adult TN-GnRH3 neurons. This study represents the first neurophysiological investigation of developing GnRH neurons in live embryos--an important advancement in understanding their potential non-reproductive roles during embryogenesis.
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Affiliation(s)
- Siddharth Ramakrishnan
- Department of Physiology, David Geffen School of Medicine at University of California-Los Angeles, Los Angeles, California 90095
| | - Wenjau Lee
- Department of Physiology, David Geffen School of Medicine at University of California-Los Angeles, Los Angeles, California 90095
| | - Sammy Navarre
- Institute of Molecular Medicine and Genetics and Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta, Georgia 30912
| | - David J. Kozlowski
- Institute of Molecular Medicine and Genetics and Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta, Georgia 30912
| | - Nancy L. Wayne
- Department of Physiology, David Geffen School of Medicine at University of California-Los Angeles, Los Angeles, California 90095
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12
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Ng Y, Wolfe A, Novaira HJ, Radovick S. Estrogen regulation of gene expression in GnRH neurons. Mol Cell Endocrinol 2009; 303:25-33. [PMID: 19428988 PMCID: PMC2680765 DOI: 10.1016/j.mce.2009.01.016] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2008] [Revised: 01/16/2009] [Accepted: 01/16/2009] [Indexed: 12/27/2022]
Abstract
Estrogen plays an essential role in the regulation of the female reproductive hormone axis, and specifically is a major regulator of GnRH neuronal function in the female brain. GnRH neuronal cell lines were used to explore the direct effects of estradiol on gene expression in GnRH neurons. The presence of estrogen receptor (ER) binding sites was established by a receptor-binding assay, and estrogen receptor alpha and beta mRNA were identified in GN11 cells and ERbeta in GT1-7 cells using RT-PCR analysis of mRNA. ERalpha was more abundantly expressed in GN11 cells than ERbeta as assessed by real-time PCR. Additionally, GN11 cells expressed significantly more of both ERalpha and beta than GT1-7 cells. Functional studies in GN11 and GT1-7 demonstrated estrogen down regulation of endogenous mouse GnRH mRNA levels using quantitative real-time PCR (qRT-PCR). Correspondingly, estradiol also reduced secretion of GnRH from both the GN11 and GT1-7 cell lines. Since estradiol has been shown to regulate progesterone receptor (PR) expression; similar studies were performed demonstrating an estradiol mediated increase in PR in both cell lines. Estradiol regulation of ER expression was also explored and these studies indicated that estradiol decreased ERalpha and ERbeta mRNA levels in a dose-dependent manner in GN11 and GT1-7 cells. These effects were blocked by the addition of the estrogen receptor antagonist ICI 182,780. Both PPT, a specific ERalpha agonist, and DPN, a specific ERbeta agonist, inhibited GnRH gene expression in GN11 cells, but only DPN inhibited GnRH gene expression in GT1-7 cells, consistent with their undetectable levels of ERalpha expression. These studies characterize a direct inhibitory effect of estradiol on GnRH in GnRH neurons, and a direct stimulatory effect of estradiol on PR gene expression. In addition, the agonist studies indicate that there is a functional overlap of ERalpha and ERbeta regulation in GnRH neurons. These studies may give insight into the molecular regulation of estrogen negative feedback in the central reproductive axis.
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Affiliation(s)
| | | | - Horacio J. Novaira
- Johns Hopkins University School of Medicine Department of Pediatrics, Division of Endocrinology
| | - Sally Radovick
- Johns Hopkins University School of Medicine Department of Pediatrics, Division of Endocrinology
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13
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Ariano P, Lo Giudice A, Marcantoni A, Vittone E, Carbone E, Lovisolo D. A diamond-based biosensor for the recording of neuronal activity. Biosens Bioelectron 2009; 24:2046-50. [DOI: 10.1016/j.bios.2008.10.017] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2008] [Revised: 10/01/2008] [Accepted: 10/21/2008] [Indexed: 10/21/2022]
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The influence of catecholamine on the migration of gonadotropin-releasing hormone-producing neurons in the rat foetuses. Brain Struct Funct 2008; 213:289-300. [PMID: 18841392 DOI: 10.1007/s00429-008-0197-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2008] [Accepted: 09/16/2008] [Indexed: 10/21/2022]
Abstract
Catecholamines (CA) play an important role in the regulation of GnRH neurons in adults, and it is probable that they control GnRH-neuron development. Migration of GnRH neurons was evaluated in male and female rats at the 17th embryonic day (E17) and E21, following the daily treatment of their pregnant mothers from the 11th to the 16th and 20th day of gestation with alpha-methyl-para-tyrosine (alphaMPT), an inhibitor of catecholamine synthesis. High-performance liquid chromatography with electrochemical detection (HPLC-ED) was used to specify the alphaMPT-induced CA depletion. There was a 50-70% decrease in dopamine and noradrenaline content in the nose and in the brain of alphaMPT-treated foetuses, proving the efficacy of this pharmacological model. Immunohistochemistry was used to evaluate the percentage (%) of GnRH neurons along their migration pathway from the vomeronasal organ (VNO) in the nose to the septo-preoptic area in the forebrain which is considered as an index of neuron migration. Special attention was paid to the topographic relationships of GnRH neurons with catecholaminergic fibres. These were observed in apposition with GnRH neurons in the entrance to the forebrain. In CA-deficient foetuses, the percentage of GnRH neurons located in the rostral regions extending from the VNO to the septum was greater than in controls. However, no statistically significant difference was found in the forebrain which extended from the septum to the retrochiasmatic area. In conclusion, these data suggest that endogenous catecholamines stimulate the GnRH neuron migration in ontogenesis.
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15
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Expression and localisation of TRPC channels in immortalised GnRH neurons. Brain Res 2008; 1230:27-36. [DOI: 10.1016/j.brainres.2008.07.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2008] [Revised: 06/10/2008] [Accepted: 07/01/2008] [Indexed: 12/27/2022]
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16
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Zaninetti R, Tacchi S, Erriquez J, Distasi C, Maggi R, Cariboni A, Condorelli F, Canonico PL, Genazzani AA. Calcineurin primes immature gonadotropin-releasing hormone-secreting neuroendocrine cells for migration. Mol Endocrinol 2007; 22:729-36. [PMID: 18032695 DOI: 10.1210/me.2007-0277] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
During development, many neurons display calcium-dependent migration, but the role of this messenger in regulating gene expression leading to this event has not yet been elucidated. Among the decoders of calcium signals is calcineurin, a Ca(2+)/calmodulin serine/threonine phosphatase that has been involved in both short-term and long-term cellular changes. By using immortalized GnRH-secreting neurons, we now show that, in vitro, Ca(2+)-dependent gene expression, proceeding via calcineurin and the transcription factor nuclear factor of activated T cells, is a key player controlling the chemomigratory potential of developing GnRH-secreting neurons. Furthermore, our data highlight the switch nature of this phosphatase, whose activation or inactivation guides cells to proceed from one genetic program to the next.
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Affiliation(s)
- R Zaninetti
- Dipartimento di Scienze Chimiche, Alimentari, Farmaceutiche e Farmacologiche and Drug and Food Biotechnology Center, Università degli Studi del Piemonte Orientale A. Avogadro, 28100 Novara, Italy
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17
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Lentini D, Guzzi F, Pimpinelli F, Zaninetti R, Cassetti A, Coco S, Maggi R, Parenti M. Polarization of caveolins and caveolae during migration of immortalized neurons. J Neurochem 2007; 104:514-23. [PMID: 17986234 DOI: 10.1111/j.1471-4159.2007.05005.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
During CNS development neurons undergo directional migration to achieve their adult localizations. To study neuronal migration, we used a model cell line of immortalized murine neurons (gonadotropin-releasing hormone expressing neurons; GN11), enriched with caveolins and caveolae invaginations that show in vitro chemotaxis upon serum exposure. Cholesterol depletion with methyl-beta-cyclodextrin induced the loss of caveolae and the inhibition of chemotaxis, thus suggesting that GN11 migration depends upon the structural integrity of caveolae. Polarization of proteins and organelles is a hallmark of cell migration. Accordingly, GN11 cells transmigrating through filter pores exhibited a polarized distribution of caveolin-1 isoform (cav-1) in the leading processes. In contrast, during two-dimensional migration cav-1 and caveolae polarized at the trailing edge. As caveolae are enriched with signaling molecules, we suggest that asymmetrical localization of caveolae may spatially orient GN11 neurons to incoming migratory signals thereby transducing them into directional migration.
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Affiliation(s)
- D Lentini
- Department of Experimental Medicine, University of Milano-Bicocca, Monza, Italy
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18
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D’Orlando C, Guzzi F, Gravati M, Biella G, Toselli M, Meneveri R, Barisani D, Parenti M. Retinoic acid- and phorbol ester-induced neuronal differentiation down-regulates caveolin expression in GnRH neurons. J Neurochem 2007; 104:1577-87. [PMID: 17988240 DOI: 10.1111/j.1471-4159.2007.05109.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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19
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Chattopadhyay N, Jeong KH, Yano S, Huang S, Pang JL, Ren X, Terwilliger E, Kaiser UB, Vassilev PM, Pollak MR, Brown EM. Calcium receptor stimulates chemotaxis and secretion of MCP-1 in GnRH neurons in vitro: potential impact on reduced GnRH neuron population in CaR-null mice. Am J Physiol Endocrinol Metab 2007; 292:E523-32. [PMID: 17003237 DOI: 10.1152/ajpendo.00372.2005] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The factors controlling the migration of mammalian gonadotropin-releasing hormone (GnRH) neurons from the nasal placode to the hypothalamus are not well understood. We studied whether the extracellular calcium-sensing receptor (CaR) promotes migration/chemotaxis of GnRH neurons. We demonstrated expression of CaR in GnRH neurons in the murine basal forebrain and in two GnRH neuronal cell lines: GT1-7 (hypothalamus derived) and GN11 (olfactory bulb derived). Elevated extracellular Ca(2+) concentrations promoted chemotaxis of both cell types, with a greater effect in GN11 cells. This effect was CaR mediated, as, in both cell types, overexpression of a dominant-negative CaR attenuated high Ca(2+)-stimulated chemotaxis. We also demonstrated expression of a beta-chemokine, monocyte chemoattractant protein-1 (MCP-1), and its receptor, CC motif receptor-2 (CCR2), in the hypothalamic GnRH neurons as well as in GT1-7 and GN11 cells. Exogenous MCP-1 stimulated chemotaxis of both cell lines in a dose-dependent fashion; the effect was greater in GN11 than in GT1-7 cells, consistent with the higher CCR2 mRNA levels in GN11 cells. Activating the CaR stimulated MCP-1 secretion in GT1-7 but not in GN11 cells. MCP-1 secreted in response to CaR stimulation is biologically active, as conditioned medium from GT1-7 cells treated with high Ca(2+) promoted chemotaxis of GN11 cells, and this effect was partially attenuated by a neutralizing antibody to MCP-1. Finally, in the preoptic area of anterior hypothalamus, the number of GnRH neurons was approximately 27% lower in CaR-null mice than in mice expressing the CaR gene. We conclude that the CaR may be a novel regulator of GnRH neuronal migration likely involving, in part, MCP-1.
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Affiliation(s)
- Naibedya Chattopadhyay
- Division of Endocrinology, Diabetes and Hypertension, Department of Medicine and Membrane Biology Program, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA.
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20
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Izvolskaia M, Duittoz AH, Ugrumov MV, Tillet Y. Tyrosine hydroxylase expression in the olfactory/respiratory epithelium in early sheep fetuses (Ovis aries). Brain Res 2006; 1083:29-38. [PMID: 16556435 DOI: 10.1016/j.brainres.2006.01.130] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2005] [Revised: 01/26/2006] [Accepted: 01/30/2006] [Indexed: 11/26/2022]
Abstract
Transient expression of tyrosine hydroxylase (TH, the first enzyme in catecholamine synthesis) has been shown in different brain and peripheral structures of various species. TH-immunoreactive neurons have been reported in the nasal region of human and rat fetuses migrating to the forebrain with GnRH neurons during embryogenesis. In the present study, immunohistochemical analysis and in situ hybridization were performed in fetal sheep and in vitro sheep embryo olfactory placode cultures to confirm this population in this species. On embryonic days 33 to 35, TH-immunoreactive cells as well as TH cDNA-hybridized cells were found in the olfactory and respiratory epithelium and were spatially separated from GnRH-immunoreactive neurons. In days 40 to 44 of gestation, TH-immunoreactive neurons were no longer observed in the olfactory epithelium, and TH-immunoreactive fibers were found on the trajectories of the olfactory nerves. At this stage, some TH-immunoreactive fibers were also labeled for GnRH. TH-immunoreactive cells were also found in primary cultures of olfactory placodes of fetal sheep at 10 to 18 days in vitro. Some of them coexpressed GnRH. These results imply that olfactory epithelium is also able to give rise to TH expressing cells in fetal sheep, but this expression is suppressed earlier in ontogenesis than in humans due to some unidentified factors not present in the primary cultures of olfactory placode. The role of TH expression remains unclear as in other previously described examples.
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Affiliation(s)
- Marina Izvolskaia
- Laboratory of Hormonal Regulations, Institute of Developmental Biology, Russian Academy of Sciences, Vavilov str., 26,119991 Moscow, Russia
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21
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Pimpinelli F, Parenti M, Guzzi F, Piva F, Hokfelt T, Maggi R. Presence of delta opioid receptors on a subset of hypothalamic gonadotropin releasing hormone (GnRH) neurons. Brain Res 2006; 1070:15-23. [PMID: 16405927 DOI: 10.1016/j.brainres.2005.11.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2005] [Revised: 10/17/2005] [Accepted: 11/02/2005] [Indexed: 12/27/2022]
Abstract
Opioid peptides exert an inhibitory effect on hypothalamic gonadotropin releasing hormone (GnRH) secretion mainly by interacting with mu-opioid receptors. Although a direct role for opioids via delta-opioid receptors (DORs) has been suggested, the presence of these receptors on GnRH neurons has never been demonstrated. In the present study, we determined the distribution of DORs in the basal hypothalamus of rat with special focus on their relation to GnRH neurons. Double-labelling immunofluorescence and confocal microscopy revealed that DORs are exclusively present in a subpopulation of GnRH nerve terminals, with the highest density in the external layer of the median eminence. We then studied the functional characteristics of DORs in an immortalized GnRH-secreting neuronal cell line (GT1-1) known to endogenously express this receptor. Here, pertussis toxin pretreatment abolished the delta-agonist (DPDPE) inhibitory effect on cAMP accumulation. We also analyzed the type of G proteins involved in the signal transduced by the DOR and showed that GT1-1 cells express the inhibitory Go and Gi2 alpha-subunits. However, only Go was down-regulated under chronic DPDPE exposure. Finally, since DOR is expressed postnatally in brain, we compared GnRH neuronal cells immortalized at different developmental stages (the more mature GT1-1 and GT1-7 cells, versus the more immature GN11 cells), evidencing that only mature neurons express DOR. In conclusion, our study indicates that a direct control of opioids via delta-receptors occurs on GnRH neurons and validates the use of GT1 cells to further investigate the nature of the DOR present on GnRH neurons.
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Affiliation(s)
- Federica Pimpinelli
- Laboratory of Developmental Neuroendocrinology, Institute of Endocrinology, University of Milano, Via G. Balzaretti, 9 20133 Milan, Italy
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22
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Cariboni A, Rakic S, Liapi A, Maggi R, Goffinet A, Parnavelas JG. Reelin provides an inhibitory signal in the migration of gonadotropin-releasing hormone neurons. Development 2005; 132:4709-18. [PMID: 16207762 DOI: 10.1242/dev.02033] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Gonadotropin-releasing hormone (GnRH) neurons, a small number of cells scattered in the hypothalamic region of the basal forebrain, play an important role in reproductive function. These cells originate in the olfactory placode and migrate into the basal forebrain in late embryonic life. Here, we show that reelin, which is expressed along the route of the migrating cells, has an inhibitory role in guiding GnRH neurons to the basal forebrain. Only a small(approximately 5%) subpopulation of these neurons expresses one of the reelin receptors (ApoER2/Lrp8), and all GnRH neurons appear to lack the intracellular adaptor protein Dab1, suggesting that the function of reelin is not mediated by the conventional signal transduction pathway. The importance of reelin in the establishment of GnRH neurons in the hypothalamus was confirmed by our finding that the brains of developing and adult reeler mice of both sexes contained a markedly reduced number of these neuroendocrine neurons. Furthermore, the testes of adult males showed dilation of seminiferous tubules and reduction in their density when compared with controls. Mutants lacking the reelin receptors ApoER2 and Vldlr, and scrambler mice lacking Dab1, showed a normal complement of GnRH neurons in the hypothalamus,confirming that the effect of reelin in their migration is independent of Dab1.
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Affiliation(s)
- Anna Cariboni
- Department of Anatomy and Developmental Biology, University College London, London WC1E 6BT, UK
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23
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Giampietro C, Luzzati F, Gambarotta G, Giacobini P, Boda E, Fasolo A, Perroteau I. Stathmin expression modulates migratory properties of GN-11 neurons in vitro. Endocrinology 2005; 146:1825-34. [PMID: 15625246 DOI: 10.1210/en.2004-0972] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Expression of stathmin, a microtubule-associated cytoplasmic protein, prominently localized in neuroproliferative zones and neuronal migration pathways in brain, was investigated in the GnRH neuroendocrine system in vivo and the function was analyzed using an in vitro approach. Here we present novel data demonstrating that GnRH migrating neurons in nasal regions and basal forebrain areas of mouse embryos express stathmin protein. In addition, this expression pattern is dependent on location, as GnRH neurons reaching the hypothalamus are stathmin negative. Immortalized GN-11 cells, which retain many characteristics of migrating GnRH neurons, strongly express stathmin mRNA and protein. The role of stathmin in GnRH migratory properties was evaluated using GN-11 cell line. We up-regulated [stathmin-transfected clones (STMN)+] and down-regulated (STMN-) the expression of stathmin in GN-11 cells, and we investigated changes in cell morphology and motility in vitro. Cells overexpressing stathmin assume a spindle-shaped morphology and their proliferation, as well as their motility, is higher with respect to parental cells. Furthermore, they do not aggregate and express low levels of cadherins compared with control cells. STMN- GN-11 cells are endowed with multipolar processes, and they show a decreased motility and express high levels of cadherin protein. Our findings suggest that stathmin plays a permissive role in GnRH cell motility, possibly via modulation of cadherins expression.
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Affiliation(s)
- Costanza Giampietro
- Department of Human and Animal Biology, University of Torino, Via Accademia Albertina 13, 10123 Torino, Italy
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24
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Givens ML, Rave-Harel N, Goonewardena VD, Kurotani R, Berdy SE, Swan CH, Rubenstein JLR, Robert B, Mellon PL. Developmental regulation of gonadotropin-releasing hormone gene expression by the MSX and DLX homeodomain protein families. J Biol Chem 2005; 280:19156-65. [PMID: 15743757 PMCID: PMC2932481 DOI: 10.1074/jbc.m502004200] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Gonadotropin-releasing hormone (GnRH) is the central regulator of the hypothalamic-pituitary-gonadal axis, controlling sexual maturation and fertility in diverse species from fish to humans. GnRH gene expression is limited to a discrete population of neurons that migrate through the nasal region into the hypothalamus during embryonic development. The GnRH regulatory region contains four conserved homeodomain binding sites (ATTA) that are essential for basal promoter activity and cell-specific expression of the GnRH gene. MSX and DLX are members of the Antennapedia class of non-Hox homeodomain transcription factors that regulate gene expression and influence development of the craniofacial structures and anterior forebrain. Here, we report that expression patterns of the Msx and Dlx families of homeodomain transcription factors largely coincide with the migratory route of GnRH neurons and co-express with GnRH in neurons during embryonic development. In addition, MSX and DLX family members bind directly to the ATTA consensus sequences and regulate transcriptional activity of the GnRH promoter. Finally, mice lacking MSX1 or DLX1 and 2 show altered numbers of GnRH-expressing cells in regions where these factors likely function. These findings strongly support a role for MSX and DLX in contributing to spatiotemporal regulation of GnRH transcription during development.
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Affiliation(s)
- Marjory L. Givens
- Departments of Reproductive Medicine and Neuroscience, University of California, San Diego, La Jolla, California 92093-0674
| | - Naama Rave-Harel
- Departments of Reproductive Medicine and Neuroscience, University of California, San Diego, La Jolla, California 92093-0674
| | - Vinodha D. Goonewardena
- Departments of Reproductive Medicine and Neuroscience, University of California, San Diego, La Jolla, California 92093-0674
| | - Reiko Kurotani
- Departments of Reproductive Medicine and Neuroscience, University of California, San Diego, La Jolla, California 92093-0674
| | - Sara E. Berdy
- Departments of Reproductive Medicine and Neuroscience, University of California, San Diego, La Jolla, California 92093-0674
| | - Christo H. Swan
- Department of Psychiatry and Langley Porter Psychiatric Institute, University of California, San Francisco, San Francisco, California 9414-0984
| | - John L. R. Rubenstein
- Department of Psychiatry and Langley Porter Psychiatric Institute, University of California, San Francisco, San Francisco, California 9414-0984
| | - Benoit Robert
- Unite de Genetique Moleculaire de la Morphogenese, Institut Pasteur, URA 2578 du CNRS, 25 rue du Dr Roux, 75724 Paris Cedex 15, France
| | - Pamela L. Mellon
- Departments of Reproductive Medicine and Neuroscience, University of California, San Diego, La Jolla, California 92093-0674
- To whom correspondence should be addressed: Dept. of Reproductive Medicine, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA 92093-0674. Tel.: 858-534-1312; Fax: 858-534-1438;
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25
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Dondi D, Piccolella M, Messi E, Demissie M, Cariboni A, Selleri S, Piva F, Samara A, Consalez GG, Maggi R. Expression and differential effects of the activation of glucocorticoid receptors in mouse gonadotropin-releasing hormone neurons. Neuroendocrinology 2005; 82:151-63. [PMID: 16498266 DOI: 10.1159/000091693] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2005] [Accepted: 12/12/2005] [Indexed: 12/27/2022]
Abstract
Prenatal exposure of rodents to glucocorticoids (Gc) affects the sexual development of the offspring, possibly interfering with the differentiation of the hypothalamic-pituitary-gonadal axis. Glucocorticoid receptors (GR) are present on gonadotropin-releasing hormone (GnRH) neurons in the rat hypothalamus, suggesting a direct effect of Gc in the control of the synthesis and/or release of the hormone. In this study, we demonstrate the colocalization of immunoreactive GR with GnRH in a subpopulation of mouse hypothalamic GnRH neurons, confirming the possible involvement of Gc in mouse GnRH neuronal physiology. Receptor-binding assay, RT-PCR, immunocytochemistry, and immunoblotting experiments carried out in GN11 immortalized GnRH neurons show the presence of GR even in the more immature mouse GnRH neurons and confirm the expression of GR in GT1-7 mature GnRH cells. In GN11 cells, the activation of GR with dexamethasone produces nuclear translocation, but does not lead to the inhibition of GnRH gene expression already reported in GT1-7 cells. Long-term exposure of GN11 cells to dexamethasone induces an epithelial-like phenotype with a reorganization of F-actin in stress fibers. Finally, we found that Gc treatment significantly decreases the migratory activity in vitro and the levels of phosphorylated focal adhesion kinase of GN11 immature neurons. In conclusion, these data indicate that GR are expressed in mouse hypothalamic GnRH neurons in vivo as well as in the immature GN11 GnRH neurons in vitro. Moreover, the effects of the GR activation in GN11 and in GT1-7 cells may be related to the neuronal maturational stage of the two cell lines, suggesting a differential role of Gc in neuronal development.
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Affiliation(s)
- Donatella Dondi
- Department of Endocrinology, Center of Excellence on Neurodegenerative Diseases, Milan, Italy
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26
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Cariboni A, Pimpinelli F, Colamarino S, Zaninetti R, Piccolella M, Rumio C, Piva F, Rugarli EI, Maggi R. The product of X-linked Kallmann's syndrome gene (KAL1) affects the migratory activity of gonadotropin-releasing hormone (GnRH)-producing neurons. Hum Mol Genet 2004; 13:2781-91. [PMID: 15471890 DOI: 10.1093/hmg/ddh309] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
X-linked Kallmann's syndrome (KS) is a genetic disease characterized by anosmia and hypogonadism due to impairment in the development of olfactory axons and in the migration of gonadotropin-releasing hormone (GnRH)-producing neurons. Deletions or point mutations of a gene located at Xp22.3 (KAL1) are responsible for the disease. This gene encodes for a secreted heparin-binding protein (KAL or anosmin-1) which exhibits similarities with cell-adhesion molecules. In the present study, we show for the first time a direct action of anosmin-1 on the migratory activity of GnRH neurons. Specifically, we exposed immortalized migrating GnRH neurons (GN11 cells) to conditioned media (CM) of COS or CHO cells transiently transfected with human KAL1 gene in microchemotaxis and collagen gel assays. We found that anosmin-1-enriched media produced a cell-specific chemotactic response of GN11 cells. None of the CM enriched on three forms of anosmin-1 carrying different missense mutations (N267K, E514K and F517L) found in patients affected by X-linked KS affected the chemomigration of GN11 cells. Anosmin binds to the GN11 cell surface by interacting with the heparan sulphate proteoglycans, and the chemotactic effect of anosmin-1-enriched CM can be specifically blocked by heparin or by heparitinase pretreatment. These results strongly suggest an involvement of anosmin-1 in the control of the migratory behaviour of GnRH neurons and provide novel information on the pathogenesis of KS.
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Affiliation(s)
- Anna Cariboni
- Department of Endocrinology, University of Milano, Milano, Italy
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