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Oda A, Inoue S, Kaneko R, Narita Y, Shiono S, Kaneko T, Tseng YC, Ohtani-Kaneko R. Involvement of IGF-1R-PI3K-AKT-mTOR pathway in increased number of GnRH3 neurons during androgen-induced sex reversal of the brain in female tilapia. Sci Rep 2022; 12:2450. [PMID: 35165334 PMCID: PMC8844422 DOI: 10.1038/s41598-022-06384-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 01/24/2022] [Indexed: 11/22/2022] Open
Abstract
The neuroplastic mechanism of sex reversal in the fish brain remains unclear due to the difficulty in identifying the key neurons involved. Mozambique tilapia show different reproductive behaviours between sexes; males build circular breeding nests while females hold and brood fertilized eggs in their mouth. In tilapia, gonadotropin-releasing hormone 3 (GnRH3) neurons, located in the terminal nerve, regulate male reproductive behaviour. Mature males have more GnRH3 neurons than mature females, and these neurons have been indicated to play a key role in the androgen-induced female-to-male sex reversal of the brain. We aimed to elucidate the signalling pathway involved in the androgen-induced increase in GnRH3 neurons in mature female tilapia. Applying inhibitors to organotypic cultures of brain slices, we showed that the insulin-like growth factor (IGF)-1 receptor (IGF-1R)/PI3K/AKT/mTOR pathway contributed to the androgen-induced increase in GnRH3 neurons. The involvement of IGF-1 and IGF-1R in 11-ketotestosterone (11-KT)-induced development of GnRH3 neurons was supported by an increase in Igf-1 mRNA shortly after 11-KT treatment, the increase of GnRH3 neurons after IGF-1 treatment and the expression of IGF-1R in GnRH3 neurons. Our findings highlight the involvement of IGF-1 and its downstream signalling pathway in the sex reversal of the tilapia brain.
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PASSARELLI A, LETTIERI A, DEMIRCI TN, MAGNI P. Gonadotropin-releasing hormone-secreting neuron development and function: an update. Minerva Endocrinol (Torino) 2022; 47:58-69. [DOI: 10.23736/s2724-6507.22.03683-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Cannarella R, Paganoni AJJ, Cicolari S, Oleari R, Condorelli RA, La Vignera S, Cariboni A, Calogero AE, Magni P. Anti-Müllerian Hormone, Growth Hormone, and Insulin-Like Growth Factor 1 Modulate the Migratory and Secretory Patterns of GnRH Neurons. Int J Mol Sci 2021; 22:ijms22052445. [PMID: 33671044 PMCID: PMC7957759 DOI: 10.3390/ijms22052445] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 02/20/2021] [Accepted: 02/24/2021] [Indexed: 12/04/2022] Open
Abstract
Anti-Müllerian hormone (AMH) is secreted by Sertoli or granulosa cells. Recent evidence suggests that AMH may play a role in the pathogenesis of hypogonadotropic hypogonadism (HH) and that its serum levels could help to discriminate HH from delayed puberty. Moreover, the growth hormone (GH)/insulin-like growth factor 1 (IGF1) system may be involved in the function of gonadotropin-releasing hormone (GnRH) neurons, as delayed puberty is commonly found in patients with GH deficiency (GHD) or with Laron syndrome, a genetic form of GH resistance. The comprehension of the stimuli enhancing the migration and secretory activity of GnRH neurons might shed light on the causes of delay of puberty or HH. With these premises, we aimed to better clarify the role of the AMH, GH, and IGF1 on GnRH neuron migration and GnRH secretion, by taking advantage of previously established models of immature (GN11 cell line) and mature (GT1-7 cell line) GnRH neurons. Expression of Amhr, Ghr, and Igf1r genes was confirmed in both cell lines. Cells were then incubated with increasing concentrations of AMH (1.5–150 ng/mL), GH (3–1000 ng/mL), or IGF1 (1.5–150 ng/mL). All hormones were able to support GN11 cell chemomigration. AMH, GH, and IGF1 significantly stimulated GnRH secretion by GT1-7 cells after a 90-min incubation. To the best of our knowledge, this is the first study investigating the direct effects of GH and IGF1 in GnRH neuron migration and of GH in the GnRH secreting pattern. Taken together with previous basic and clinical studies, these findings may provide explanatory mechanisms for data, suggesting that AMH and the GH-IGF1 system play a role in HH or the onset of puberty.
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Affiliation(s)
- Rossella Cannarella
- Department of Clinical and Experimental Medicine, University of Catania, 95123 Catania, Italy; (R.A.C.); (S.L.V.); (A.E.C.)
- Correspondence: (R.C.); (A.C.)
| | - Alyssa J. J. Paganoni
- Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, 20133 Milan, Italy; (A.J.J.P.); (S.C.); (R.O.); (P.M.)
| | - Stefania Cicolari
- Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, 20133 Milan, Italy; (A.J.J.P.); (S.C.); (R.O.); (P.M.)
| | - Roberto Oleari
- Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, 20133 Milan, Italy; (A.J.J.P.); (S.C.); (R.O.); (P.M.)
| | - Rosita A. Condorelli
- Department of Clinical and Experimental Medicine, University of Catania, 95123 Catania, Italy; (R.A.C.); (S.L.V.); (A.E.C.)
| | - Sandro La Vignera
- Department of Clinical and Experimental Medicine, University of Catania, 95123 Catania, Italy; (R.A.C.); (S.L.V.); (A.E.C.)
| | - Anna Cariboni
- Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, 20133 Milan, Italy; (A.J.J.P.); (S.C.); (R.O.); (P.M.)
- Correspondence: (R.C.); (A.C.)
| | - Aldo E. Calogero
- Department of Clinical and Experimental Medicine, University of Catania, 95123 Catania, Italy; (R.A.C.); (S.L.V.); (A.E.C.)
| | - Paolo Magni
- Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, 20133 Milan, Italy; (A.J.J.P.); (S.C.); (R.O.); (P.M.)
- IRCCS MultiMedica, Sesto S. Giovanni, 20099 Milan, Italy
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Lainez NM, Coss D. Obesity, Neuroinflammation, and Reproductive Function. Endocrinology 2019; 160:2719-2736. [PMID: 31513269 PMCID: PMC6806266 DOI: 10.1210/en.2019-00487] [Citation(s) in RCA: 82] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 09/04/2019] [Indexed: 12/13/2022]
Abstract
The increasing occurrence of obesity has become a significant public health concern. Individuals with obesity have higher prevalence of heart disease, stroke, osteoarthritis, diabetes, and reproductive disorders. Reproductive problems include menstrual irregularities, pregnancy complications, and infertility due to anovulation, in women, and lower testosterone and diminished sperm count, in men. In particular, women with obesity have reduced levels of both gonadotropin hormones, and, in obese men, lower testosterone is accompanied by diminished LH. Taken together, these findings indicate central dysregulation of the hypothalamic-pituitary-gonadal axis, specifically at the level of the GnRH neuron function, which is the final brain output for the regulation of reproduction. Obesity is a state of hyperinsulinemia, hyperlipidemia, hyperleptinemia, and chronic inflammation. Herein, we review recent advances in our understanding of how these metabolic and immune changes affect hypothalamic function and regulation of GnRH neurons. In the latter part, we focus on neuroinflammation as a major consequence of obesity and discuss findings that reveal that GnRH neurons are uniquely positioned to respond to inflammatory changes.
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Affiliation(s)
- Nancy M Lainez
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, California
| | - Djurdjica Coss
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, California
- Correspondence: Djurdjica Coss, PhD, Division of Biomedical Sciences, School of Medicine, University of California, Riverside, 303 SOM Research Building, 900 University Avenue, Riverside, California 92521. E-mail:
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Lainez NM, Coss D. Leukemia Inhibitory Factor Represses GnRH Gene Expression via cFOS during Inflammation in Male Mice. Neuroendocrinology 2019; 108:291-307. [PMID: 30630179 PMCID: PMC6561803 DOI: 10.1159/000496754] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2018] [Accepted: 01/09/2019] [Indexed: 12/12/2022]
Abstract
BACKGROUND The mechanisms whereby neuroinflammation negatively affects neuronal function in the hypothalamus are not clear. Our previous study determined that obesity-mediated chronic inflammation elicits sex-specific impairment in reproductive function via reduction in spine density in gonadotropin-releasing hormone (GnRH) neurons. Neuroinflammation and subsequent decrease in GnRH neuron spine density was specific for male mice, while protection in females was independent of ovarian estrogens. METHODS To examine if neuroinflammation-induced cytokines can directly regulate GnRH gene expression, herein we examined signaling pathways and mechanisms in males in vivo and in GnRH-expressing cell line, GT1-7. RESULTS GnRH neurons express cytokine receptors, and chronic or acute neuroinflammation represses GnRH gene expression in vivo. Leukemia inhibitory factor (LIF) in particular represses GnRH expression in GT1-7 cells, while other cytokines do not. STAT3 and MAPK pathways are activated following LIF treatment, but only MAPK pathway, specifically p38α, is sufficient to repress the GnRH gene. LIF induces cFOS that represses the GnRH gene via the -1,793 site in the enhancer region. In vivo, following high-fat diet, cFOS is induced in GnRH neurons and neurons juxtaposed to the leaky blood brain barrier of the organum vasculosum of the lamina terminalis, but not in the neurons further away. CONCLUSION Our results indicate that the increase in LIF due to neuroinflammation induces cFOS and represses the GnRH gene. Therefore, in addition to synaptic changes in GnRH neurons, neuroinflammatory cytokines directly regulate gene expression and reproductive function, and the specificity for neuronal targets may stem from the proximity to the fenestrated capillaries.
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Affiliation(s)
- Nancy M Lainez
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, California, USA
| | - Djurdjica Coss
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, California, USA,
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Ko EK, Chorich LP, Sullivan ME, Cameron RS, Layman LC. JAK/STAT signaling pathway gene expression is reduced following Nelf knockdown in GnRH neurons. Mol Cell Endocrinol 2018; 470:151-159. [PMID: 29050862 DOI: 10.1016/j.mce.2017.10.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 10/13/2017] [Accepted: 10/14/2017] [Indexed: 12/27/2022]
Abstract
Hypothalamic gonadotropin releasing hormone (GnRH) is crucial for the proper function of the hypothalamic-pituitary-gonadal (HPG) axis, subsequent puberty, and reproduction. When GnRH neuron migration or GnRH regulation is impaired, hypogonadotropic hypogonadism results. Mutations in the gene for nasal embryonic luteinizing hormone-releasing factor (NELF) have been identified in GnRH-deficient humans. NELF is a predominantly nuclear protein that may participate in gene transcription, but the genes NELF regulates are unknown. To address this question, RNA was extracted from NLT GnRH neuronal cells following either stable Nelf knockdown or scrambled control and subjected to cDNA arrays. Transcription factors and cell migration gene expression was altered most commonly. Members of the Janus kinase/signal transducers and activators of transcription (JAK/STAT) pathway, including Stat1, Stat2, Stat5a, Jak2, Irf7 and Irf9, were significantly down regulated as assessed by RT-qPCR. Protein levels of STAT1, phospho-STAT1, and JAK2 were reduced, but the protein level of phospho-JAK2 was not. These findings suggest a role for NELF in the regulation of the JAK/STAT signaling pathway, which have important functions in GnRH neurons.
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Affiliation(s)
- Eun Kyung Ko
- Section of Reproductive Endocrinology, Infertility, & Genetics, Department of Obstetrics & Gynecology, Department of Neuroscience and Regenerative Medicine, Augusta University, Augusta, GA 30912, United States; Department of Neuroscience and Regenerative Medicine, Augusta University, Augusta, GA 30912, United States
| | - Lynn P Chorich
- Section of Reproductive Endocrinology, Infertility, & Genetics, Department of Obstetrics & Gynecology, Department of Neuroscience and Regenerative Medicine, Augusta University, Augusta, GA 30912, United States
| | - Megan E Sullivan
- Section of Reproductive Endocrinology, Infertility, & Genetics, Department of Obstetrics & Gynecology, Department of Neuroscience and Regenerative Medicine, Augusta University, Augusta, GA 30912, United States
| | - Richard S Cameron
- Department of Neuroscience and Regenerative Medicine, Augusta University, Augusta, GA 30912, United States
| | - Lawrence C Layman
- Section of Reproductive Endocrinology, Infertility, & Genetics, Department of Obstetrics & Gynecology, Department of Neuroscience and Regenerative Medicine, Augusta University, Augusta, GA 30912, United States; Department of Neuroscience and Regenerative Medicine, Augusta University, Augusta, GA 30912, United States.
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Signaling of cytokines is important in regulation of GnRH neurons. Mol Neurobiol 2011; 45:119-25. [PMID: 22161498 DOI: 10.1007/s12035-011-8224-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Accepted: 12/05/2011] [Indexed: 01/17/2023]
Abstract
Cytokines encompass a broad class of peptides that mediate signals in a broad range of physiological situations including inflammation, infection, and obesity. The cytokine receptor-associated tyrosine kinase, Jak2, is one of the most important proteins mediating cytokine signaling pathway activation. Recently, our group has demonstrated that Jak2 signaling in the gonadotropin-releasing hormone (GnRH) neuron plays a critical role in fertility in males and females, implicating cytokine activation of the neuron in GnRH neuronal development and function. To date, the specific cytokine(s) essential for activating Jak2 during neuroendocrine development are not known. In this article, we review the evidence for the role of several class 1 cytokines in regulating GnRH neuronal development, GnRH secretion, and GnRH expression.
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Abstract
Gonadotropin-releasing hormone (GnRH) neurons represent the final common output of signals from the brain that regulates reproductive function. A wide range of environmental factors impact GnRH neuron activity including disease, stress, nutrition, and seasonal cues, as well as gonadal steroid hormones. The CNS response is thought to be mediated, at least in part, through intermediate signaling molecules that affect GnRH neuronal activity. In vitro, GnRH neuronal cell lines respond to a variety of ligands that activate the Jak (Janus-activated kinase)/STAT (signal transducers and activators of transcription) intracellular signaling pathway. To determine its biological function in reproduction, we used Cre (cAMP response element)/LoxP technology to generate GnRH neuron-specific Jak2 conditional knock-out (Jak2 G(-/-)) mice. GnRH mRNA levels were reduced in Jak2 G(-/-) mice when compared with controls, while the number of GnRH neurons was equivalent, indicating a reduction in GnRH gene expression. Secretion of GnRH is also reduced as basal serum luteinizing hormone (LH) levels were significantly lower in female Jak2 G(-/-) mice while the pituitary responded normally to exogenous GnRH. Preovulatory LH surge levels were blunted in Jak2 G(-/-) mice, which was correlated with reduced GnRH neuronal activation as assessed by c-Fos. However, the activation of GnRH neurons following release from estrogen-negative feedback is retained. Female Jak2 G(-/-) mice exhibited significantly delayed puberty and first estrus, abnormal estrous cyclicity, and impaired fertility. These results demonstrate an essential role for Jak2 signaling in GnRH neurons for normal reproductive development and fertility in female mice.
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