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Oliveira VEDM, Evrard F, Faure MC, Bakker J. Social isolation and aggression training lead to escalated aggression and hypothalamus-pituitary-gonad axis hyperfunction in mice. Neuropsychopharmacology 2024:10.1038/s41386-024-01808-3. [PMID: 38337026 DOI: 10.1038/s41386-024-01808-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Revised: 12/30/2023] [Accepted: 01/17/2024] [Indexed: 02/12/2024]
Abstract
Although the participation of sex hormones and sex hormone-responsive neurons in aggressive behavior has been extensively studied, the role of other systems within the hypothalamus-pituitary-gonadal (HPG) axis remains elusive. Here we assessed how the gonadotropin-releasing hormone (GnRH) and kisspeptin systems are impacted by escalated aggression in male mice. We used a combination of social isolation and aggression training (IST) to exacerbate mice's aggressive behavior. Next, low-aggressive (group-housed, GH) and highly aggressive (IST) mice were compared regarding neuronal activity in the target populations and hormonal levels, using immunohistochemistry and ELISA, respectively. Finally, we used pharmacological and viral approaches to manipulate neuropeptide signaling and expression, subsequently evaluating its effects on behavior. IST mice exhibited enhanced aggressive behavior compared to GH controls, which was accompanied by elevated neuronal activity in GnRH neurons and arcuate nucleus kisspeptin neurons. Remarkably, IST mice presented an increased number of kisspeptin neurons in the anteroventral periventricular nucleus (AVPV). In addition, IST mice exhibited elevated levels of luteinizing hormone (LH) in serum. Accordingly, activation and blockade of GnRH receptors (GnRHR) exacerbated and reduced aggression, respectively. Surprisingly, kisspeptin had intricate effects on aggression, i.e., viral ablation of AVPV-kisspeptin neurons impaired the training-induced rise in aggressive behavior whereas kisspeptin itself strongly reduced aggression in IST mice. Our results indicate that IST enhances aggressive behavior in male mice by exacerbating HPG-axis activity. Particularly, increased GnRH neuron activity and GnRHR signaling were found to underlie aggression whereas the relationship with kisspeptin remains puzzling.
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Affiliation(s)
- Vinícius Elias de Moura Oliveira
- Laboratory of Neuroendocrinology, GIGA-Neurosciences, University of Liege, 4000, Liege, Belgium.
- Institute of Pathophysiology, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, 55128, Mainz, Germany.
| | - Florence Evrard
- Laboratory of Neuroendocrinology, GIGA-Neurosciences, University of Liege, 4000, Liege, Belgium
| | - Melanie C Faure
- Laboratory of Neuroendocrinology, GIGA-Neurosciences, University of Liege, 4000, Liege, Belgium
| | - Julie Bakker
- Laboratory of Neuroendocrinology, GIGA-Neurosciences, University of Liege, 4000, Liege, Belgium.
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Clarkson J, Yip SH, Porteous R, Kauff A, Heather AK, Herbison AE. CRISPR-Cas9 knockdown of ESR1 in preoptic GABA-kisspeptin neurons suppresses the preovulatory surge and estrous cycles in female mice. eLife 2023; 12:RP90959. [PMID: 38126277 PMCID: PMC10735218 DOI: 10.7554/elife.90959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2023] Open
Abstract
Evidence suggests that estradiol-sensing preoptic area GABA neurons are involved in the preovulatory surge mechanism necessary for ovulation. In vivo CRISPR-Cas9 editing was used to achieve a 60-70% knockdown in estrogen receptor alpha (ESR1) expression by GABA neurons located within the regions of the rostral periventricular area of the third ventricle (RP3V) and medial preoptic nuclei (MPN) in adult female mice. Mice exhibited variable reproductive phenotypes with the only significant finding being mice with bilateral ESR1 deletion in RP3V GABA neurons having reduced cFos expression in gonadotropin-releasing hormone (GnRH) neurons at the time of the surge. One sub-population of RP3V GABA neurons expresses kisspeptin. Re-grouping ESR1-edited mice on the basis of their RP3V kisspeptin expression revealed a highly consistent phenotype; mice with a near-complete loss of kisspeptin immunoreactivity displayed constant estrus and failed to exhibit surge activation but retained pulsatile luteinizing hormone (LH) secretion. These observations demonstrate that ESR1-expressing GABA-kisspeptin neurons in the RP3V are essential for the murine preovulatory LH surge mechanism.
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Affiliation(s)
- Jenny Clarkson
- Centre for NeuroendocrinologyDunedinNew Zealand
- Department of Physiology, University of Otago School of Biomedical SciencesDunedinNew Zealand
| | - Siew Hoong Yip
- Centre for NeuroendocrinologyDunedinNew Zealand
- Department of Physiology, University of Otago School of Biomedical SciencesDunedinNew Zealand
| | - Robert Porteous
- Centre for NeuroendocrinologyDunedinNew Zealand
- Department of Physiology, University of Otago School of Biomedical SciencesDunedinNew Zealand
| | - Alexia Kauff
- Department of Physiology, University of Otago School of Biomedical SciencesDunedinNew Zealand
| | - Alison K Heather
- Department of Physiology, University of Otago School of Biomedical SciencesDunedinNew Zealand
| | - Allan E Herbison
- Centre for NeuroendocrinologyDunedinNew Zealand
- Department of Physiology, University of Otago School of Biomedical SciencesDunedinNew Zealand
- Department of Physiology, Development and Neuroscience, University of CambridgeCambridgeUnited Kingdom
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Exposure to the pesticides linuron, dimethomorph and imazalil alters steroid hormone profiles and gene expression in developing rat ovaries. Toxicol Lett 2022; 373:114-122. [PMID: 36410587 DOI: 10.1016/j.toxlet.2022.11.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 11/13/2022] [Accepted: 11/17/2022] [Indexed: 11/23/2022]
Abstract
Inhibition of androgen signaling during critical stages of ovary development can disrupt folliculogenesis with potential consequences for reproductive function later in life. Many environmental chemicals can inhibit the androgen signaling pathway, which raises the question if developmental exposure to anti-androgenic chemicals can negatively impact female fertility. Here, we report on altered reproductive hormone profiles in prepubertal female rats following developmental exposure to three pesticides with anti-androgenic potential: linuron (25 and 50 mg/kg bw/d), dimethomorph (60 and 180 mg/kg bw/d) and imazalil (8 and 24 mg/kg bw/d). Dams were orally exposed from gestational day 7 (dimethomorph and imazalil) or 13 (linuron) until birth, then until end of dosing at early postnatal life. Linuron and dimethomorph induced dose-related reductions to plasma corticosterone levels, whereas imazalil mainly suppressed gonadotropin levels. In the ovaries, expression levels of target genes were affected by linuron and dimethomorph, suggesting impaired follicle growth. Based on our results, we propose that anti-androgenic chemicals can negatively impact female reproductive development. This highlights a need to integrate data from all levels of the hypothalamic-pituitary-gonadal axis, as well as the hypothalamic-pituitary-adrenal axis, when investigating the potential impact of endocrine disruptors on female reproductive development and function.
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González-Flores O, Pfaus JG, Luna-Hernández A, Montes-Narváez O, Domínguez-Ordóñez R, Tecamachaltzi-Silvarán MB, García-Juárez M. Estradiol and progesterone-induced lordosis behavior is modulated by both the Kisspeptin receptor and melanin-concentrating hormone in estradiol benzoate-primed rats. Horm Behav 2022; 146:105257. [PMID: 36115135 DOI: 10.1016/j.yhbeh.2022.105257] [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: 04/26/2022] [Revised: 08/22/2022] [Accepted: 08/30/2022] [Indexed: 11/16/2022]
Abstract
Intracerebroventricular (ICV) administration of estradiol benzoate (E2B) and progesterone (P) induces intense lordosis behavior in ovariectomized rats primed peripherally with E2B. The present study tested the hypothesis that the Kisspeptin (Kiss) and melanin-concentrating hormone (MCH) pathways regulate female sexual behavior induced by these steroid hormones. In Experiment 1, we tested the relevance of the Kiss pathway by ICV infusion of its inhibitor, kiss-234, before administration of E2B or P in estrogen-primed rats. Lordosis induced by E2B alone or with the addition of P was reduced significantly at 30, 120, and 240 min. In Experiment 2, ICV infusion of MCH 30 min before E2B or P significantly reduced lordosis in rats primed with E2B alone. These data support the hypothesis that the Kiss and MCH pathways, which can release or modulate gonadotropin-releasing hormone (GnRH), are involved in E2B- and P-induced lordosis.
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Affiliation(s)
- Oscar González-Flores
- Centro de Investigación en Reproducción Animal, Universidad Autónoma de Tlaxcala-CINVESTAV, Tlaxcala, México
| | - James G Pfaus
- Department of Psychology and Life Sciences, Charles University, Prague, Czech Republic; Czech National Institute of Mental Health, Klecany, Czech Republic
| | - Ailyn Luna-Hernández
- Centro de Investigación en Reproducción Animal, Universidad Autónoma de Tlaxcala-CINVESTAV, Tlaxcala, México; Maestría en Ciencias Biológicas, Universidad Autónoma de Tlaxcala, Tlaxcala, México
| | - Omar Montes-Narváez
- Centro de Investigación en Reproducción Animal, Universidad Autónoma de Tlaxcala-CINVESTAV, Tlaxcala, México; Doctorado en Ciencias Biológicas, Universidad Autónoma de Tlaxcala, Tlaxcala, México
| | - Raymundo Domínguez-Ordóñez
- Centro de Investigación en Reproducción Animal, Universidad Autónoma de Tlaxcala-CINVESTAV, Tlaxcala, México; Licenciatura en Ingeniería Agronómica y Zootecnia, CRC, Benemérita Universidad Autónoma de Puebla, México
| | | | - Marcos García-Juárez
- Centro de Investigación en Reproducción Animal, Universidad Autónoma de Tlaxcala-CINVESTAV, Tlaxcala, México.
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Oliveira VEDM, Bakker J. Neuroendocrine regulation of female aggression. Front Endocrinol (Lausanne) 2022; 13:957114. [PMID: 36034455 PMCID: PMC9399833 DOI: 10.3389/fendo.2022.957114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 07/19/2022] [Indexed: 11/13/2022] Open
Abstract
Classically the neurobiology of aggression has been studied exclusively in males. Thus, females have been considered mildly aggressive except during lactation. Interestingly, recent studies in rodents and humans have revealed that non-lactating females can show exacerbated and pathological aggression similarly to males. This review provides an overview of recent findings on the neuroendocrine mechanisms regulating aggressive behavior in females. In particular, the focus will be on novel rodent models of exaggerated aggression established in non-lactating females. Among the neuromodulatory systems influencing female aggression, special attention has been given to sex-steroids and sex-steroid-sensitive neuronal populations (i.e., the core nuclei of the neural pathway of aggression) as well as to the neuropeptides oxytocin and vasopressin which are major players in the regulation of social behaviors.
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Lin XH, Lass G, Kong LS, Wang H, Li XF, Huang HF, O’Byrne KT. Optogenetic Activation of Arcuate Kisspeptin Neurons Generates a Luteinizing Hormone Surge-Like Secretion in an Estradiol-Dependent Manner. Front Endocrinol (Lausanne) 2021; 12:775233. [PMID: 34795643 PMCID: PMC8593229 DOI: 10.3389/fendo.2021.775233] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 10/18/2021] [Indexed: 01/31/2023] Open
Abstract
Traditionally, the anteroventral periventricular (AVPV) nucleus has been the brain area associated with luteinizing hormone (LH) surge secretion in rodents. However, the role of the other population of hypothalamic kisspeptin neurons, in the arcuate nucleus (ARC), has been less well characterized with respect to surge generation. Previous experiments have demonstrated ARC kisspeptin knockdown reduced the amplitude of LH surges, indicating that they have a role in surge amplification. The present study used an optogenetic approach to selectively stimulate ARC kisspeptin neurons and examine the effect on LH surges in mice with different hormonal administrations. LH level was monitored from 13:00 to 21:00 h, at 30-minute intervals. Intact Kiss-Cre female mice showed increased LH secretion during the stimulation period in addition to displaying a spontaneous LH surge around the time of lights off. In ovariectomized Kiss-Cre mice, optogenetic stimulation was followed by a surge-like secretion of LH immediately after the stimulation period. Ovariectomized Kiss-Cre mice with a low dose of 17β-estradiol (OVX+E) replacement displayed a surge-like increase in LH release during period of optic stimulation. No LH response to the optic stimulation was observed in OVX+E mice on the day of estradiol benzoate (EB) treatment (day 1). However, after administration of progesterone (day 2), all OVX+E+EB+P mice exhibited an LH surge during optic stimulation. A spontaneous LH surge also occurred in these mice at the expected time. Taken together, these results help to affirm the fact that ARC kisspeptin may have a novel amplificatory role in LH surge production, which is dependent on the gonadal steroid milieu.
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Affiliation(s)
- Xian-Hua Lin
- Obstetrics and Gynecology Hospital, Institute of Reproduction and Development, Fudan University, Shanghai, China
- Department of Women and Children’s Health, Faculty of Life Sciences and Medicine, King’s College London, London, United Kingdom
| | - Geffen Lass
- Obstetrics and Gynecology Hospital, Institute of Reproduction and Development, Fudan University, Shanghai, China
| | - Ling-Si Kong
- Obstetrics and Gynecology Hospital, Institute of Reproduction and Development, Fudan University, Shanghai, China
| | - Hui Wang
- Department of Obstetrics and Gynecology, Maternal and Child Health Hospital of Songjiang District, Shanghai, China
| | - Xiao-Feng Li
- Obstetrics and Gynecology Hospital, Institute of Reproduction and Development, Fudan University, Shanghai, China
| | - He-Feng Huang
- Department of Women and Children’s Health, Faculty of Life Sciences and Medicine, King’s College London, London, United Kingdom
| | - Kevin T. O’Byrne
- Obstetrics and Gynecology Hospital, Institute of Reproduction and Development, Fudan University, Shanghai, China
- *Correspondence: Kevin T. O’Byrne, kevin.o’
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Negrón AL, Yu G, Boehm U, Acosta-Martínez M. Targeted Deletion of PTEN in Kisspeptin Cells Results in Brain Region- and Sex-Specific Effects on Kisspeptin Expression and Gonadotropin Release. Int J Mol Sci 2020; 21:ijms21062107. [PMID: 32204355 PMCID: PMC7139936 DOI: 10.3390/ijms21062107] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 03/16/2020] [Accepted: 03/17/2020] [Indexed: 02/06/2023] Open
Abstract
Kisspeptin-expressing neurons in the anteroventral periventricular nucleus (AVPV) and the arcuate nucleus (ARC) of the hypothalamus relay hormonal and metabolic information to gonadotropin-releasing hormone neurons, which in turn regulate pituitary and gonadal function. Phosphatase and tensin homolog (PTEN) blocks phosphatidylinositol 3-kinase (PI3K), a signaling pathway utilized by peripheral factors to transmit their signals. However, whether PTEN signaling in kisspeptin neurons helps to integrate peripheral hormonal cues to regulate gonadotropin release is unknown. To address this question, we generated mice with a kisspeptin cell-specific deletion of Pten (Kiss-PTEN KO), and first assessed kisspeptin protein expression and gonadotropin release in these animals. Kiss-PTEN KO mice displayed a profound sex and region-specific kisspeptin neuron hyperthrophy. We detected both kisspeptin neuron hyperthrophy as well as increased kisspeptin fiber densities in the AVPV and ARC of Kiss-PTEN KO females and in the ARC of Kiss-PTEN KO males. Moreover, Kiss-PTEN KO mice showed a reduced gonadotropin release in response to gonadectomy. We also found a hyperactivation of mTOR, a downstream PI3K target and central regulator of cell metabolism, in the AVPV and ARC of Kiss-PTEN KO females but not males. Fasting, known to inhibit hypothalamic kisspeptin expression and luteinizing hormone levels, failed to induce these changes in Kiss-PTEN KO females. We conclude that PTEN signaling regulates kisspeptin protein synthesis in both sexes and that its role as a metabolic signaling molecule in kisspeptin neurons is sex-specific.
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Affiliation(s)
- Ariel L. Negrón
- Graduate Program in Neuroscience, Stony Brook University, Stony Brook, NY 11794, USA;
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY 11794, USA;
| | - Guiqin Yu
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY 11794, USA;
| | - Ulrich Boehm
- Experimental Pharmacology, Center for Molecular Signaling (PZMS), Saarland University School of Medicine, 66421 Homburg, Germany;
| | - Maricedes Acosta-Martínez
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY 11794, USA;
- Correspondence: ; Tel.: +1-631-444-6075; Fax: +1-631-444-3432
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Khbouz B, de Bournonville C, Court L, Taziaux M, Corona R, Arnal JF, Lenfant F, Cornil CA. Role for the membrane estrogen receptor alpha in the sexual differentiation of the brain. Eur J Neurosci 2019; 52:2627-2645. [PMID: 31833601 DOI: 10.1111/ejn.14646] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 10/30/2019] [Accepted: 12/05/2019] [Indexed: 12/25/2022]
Abstract
Estrogens exert pleiotropic effects on multiple physiological and behavioral responses. Male and female sexual behavior in rodents constitutes some of the best-characterized responses activated by estrogens in adulthood and largely depend on ERα. Evidence exists that nucleus- and membrane-initiated estrogen signaling cooperate to orchestrate the activation of these behaviors both in short- and long-term. However, questions remain regarding the mechanism(s) and receptor(s) involved in the early brain programming during development to organize the circuits underlying sexually differentiated responses. Taking advantage of a mouse model harboring a mutation of the ERα palmitoylation site, which prevents membrane ERα signaling (mERα; ERα-C451A), this study investigated the role of mERα on the expression of male and female sexual behavior and neuronal populations that differ between sexes. The results revealed no genotype effect on the expression of female sexual behavior, while male sexual behavior was significantly reduced, but not abolished, in males homozygous for the mutation. Similarly, the number of kisspeptin- (Kp-ir) and calbindin-immunoreactive (Cb-ir) neurons in the anteroventral periventricular nucleus (AVPv) and the sexually dimorphic nucleus of the preoptic area (SDN-POA), respectively, were not different between genotypes in females. In contrast, homozygous males showed increased numbers of Kp-ir and decreased numbers of Cb-ir neurons compared to wild-types, thus leading to an intermediate phenotype between females and wild-type males. Importantly, females neonatally treated with estrogens exhibited the same neurochemical phenotype as their corresponding genotype among males. Together, these data provide evidence that mERα is involved in the perinatal programming of the male brain.
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Affiliation(s)
- Badr Khbouz
- GIGA Neurosciences, University of Liège, Liège, Belgium
| | | | - Lucas Court
- GIGA Neurosciences, University of Liège, Liège, Belgium
| | | | - Rebeca Corona
- GIGA Neurosciences, University of Liège, Liège, Belgium
| | - Jean-François Arnal
- INSERM/UPS UMR 1048-I2MC, Institut des Maladies Métaboliques et Cardiovasculaires, Toulouse, France
| | - Françoise Lenfant
- INSERM/UPS UMR 1048-I2MC, Institut des Maladies Métaboliques et Cardiovasculaires, Toulouse, France
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Shay DA, Vieira-Potter VJ, Rosenfeld CS. Sexually Dimorphic Effects of Aromatase on Neurobehavioral Responses. Front Mol Neurosci 2018; 11:374. [PMID: 30374289 PMCID: PMC6196265 DOI: 10.3389/fnmol.2018.00374] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2018] [Accepted: 09/21/2018] [Indexed: 01/16/2023] Open
Abstract
Aromatase is the enzyme responsible for converting testosterone to estradiol. In mammals, aromatase is expressed in the testes, ovaries, brain, and other tissues. While estrogen is traditionally associated with reproduction and sexual behavior in females, our current understanding broadens this perspective to include such biological functions as metabolism and cognition. It is now well-recognized that aromatase plays a vital lifetime role in brain development and neurobehavioral function in both sexes. Thus, ongoing investigations seek to highlight potentially vital sex differences in the role of aromatase, particularly regarding its centrally mediated effects. To characterize the role of aromatase in mediating such functions, effects of aromatase inhibitor (AI) treatments on humans and animal models have been determined. Aromatase knockout (ArKO) mice that systemically lack the enzyme have also been employed. Humans possessing mutations in the gene encoding aromatase, CYP19, have also provided critical insight into how aromatase affects brain function in a possible sex-dependent manner. A better understanding of how AIs, used to treat breast cancer and other clinical conditions, may detrimentally affect neurobehavioral responses will likely promote development of future therapies to combat these effects. Herein, we will provide a critical review of the current knowledge of sex differences in aromatase regulation of various neurobehavioral functions. Although many species have been used to better understand the functions of aromatase, this review focuses on rodent models and humans. Critical gaps in our present understanding of this area will be considered, and important future research directions will be discussed.
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Affiliation(s)
- Dusti A Shay
- Nutrition and Exercise Physiology, University of Missouri Columbia, MO, United States
| | | | - Cheryl S Rosenfeld
- Bond Life Sciences Center, University of Missouri Columbia, MO, United States.,Thompson Center for Autism and Neurobehavioral Disorders, University of Missouri Columbia, MO, United States.,Department of Biomedical Sciences, University of Missouri Columbia, MO, United States
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Abstract
Contribution to Special Issue on Fast effects of steroids. The concept that the positive feedback effect of ovarian estradiol (E2) results in GnRH and gonadotropin surges is a well-established principle. However, a series of studies investigating the rapid action of E2 in female rhesus monkeys has led to a new concept that neuroestradiol, synthesized and released in the hypothalamus, also contributes to regulation of the preovulatory GnRH surge. This unexpected finding started from our surprising observation that E2 induces rapid stimulatory action in GnRH neurons in vitro. Subsequently, we confirmed that a similar rapid stimulatory action of E2 occurs in vivo. Unlike subcutaneous injection of E2 benzoate (EB), a brief (10-20 min), direct infusion of EB into the median eminence in ovariectomized (OVX) female monkeys rapidly stimulates release of GnRH and E2 in a pulsatile manner, and the EB-induced GnRH and E2 release is blocked by simultaneous infusion of the aromatase inhibitor, letrozole. This suggests that stimulated release of E2 is of hypothalamic origin. To further determine the role of neuroestradiol we examined the effects of letrozole on EB-induced GnRH and LH surges in OVX females. Results indicate that letrozole treatment greatly attenuated the EB-induced GnRH and LH surges. Collectively, neuroestradiol released from the hypothalamus appears to be necessary for the positive feedback effect of E2 on the GnRH/LH surge.
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Affiliation(s)
- Ei Terasawa
- Wisconsin National Primate Research Center, University of Wisconsin, Madison, WI 53715, United States; Department of Pediatrics, University of Wisconsin, Madison, WI 53706, United States.
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Obligatory role of hypothalamic neuroestradiol during the estrogen-induced LH surge in female ovariectomized rhesus monkeys. Proc Natl Acad Sci U S A 2017; 114:13804-13809. [PMID: 29229849 DOI: 10.1073/pnas.1716097115] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Negative and positive feedback effects of ovarian 17β-estradiol (E2) regulating release of gonadotropin releasing hormone (GnRH) and luteinizing hormone (LH) are pivotal events in female reproductive function. While ovarian feedback on hypothalamo-pituitary function is a well-established concept, the present study shows that neuroestradiol, locally synthesized in the hypothalamus, is a part of estrogen's positive feedback loop. In experiment 1, E2 benzoate-induced LH surges in ovariectomized female monkeys were severely attenuated by systemic administration of the aromatase inhibitor, letrozole. Aromatase is the enzyme responsible for synthesis of E2 from androgens. In experiment 2, using microdialysis, GnRH and kisspeptin surges induced by E2 benzoate were similarly attenuated by infusion of letrozole into the median eminence of the hypothalamus. Therefore, neuroestradiol is an integral part of the hypothalamic engagement in response to elevated circulating E2 Collectively, we will need to modify the concept of estrogen's positive feedback mechanism.
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Expression of ESR1 in Glutamatergic and GABAergic Neurons Is Essential for Normal Puberty Onset, Estrogen Feedback, and Fertility in Female Mice. J Neurosci 2016; 35:14533-43. [PMID: 26511244 DOI: 10.1523/jneurosci.1776-15.2015] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Circulating estradiol exerts a profound influence on the activity of the gonadotropin-releasing hormone (GnRH) neuronal network controlling fertility. Using genetic strategies enabling neuron-specific deletion of estrogen receptor α (Esr1), we examine here whether estradiol-modulated GABA and glutamate transmission are critical for the functioning of the GnRH neuron network in the female mouse. Using Vgat- and Vglut2-ires-Cre knock-in mice and ESR1 immunohistochemistry, we demonstrate that subpopulations of GABA and glutamate neurons throughout the limbic forebrain express ESR1, with ESR1-GABAergic neurons being more widespread and numerous than ESR1-glutamatergic neurons. We crossed Vgat- and Vglut2-ires-Cre mice with an Esr1(lox/lox) line to generate animals with GABA-neuron-specific or glutamate-neuron-specific deletion of Esr1. Vgat-ires-Cre;Esr1(lox/lox) mice were infertile, with abnormal estrous cycles, and exhibited a complete failure of the estrogen positive feedback mechanism responsible for the preovulatory GnRH surge. However, puberty onset and estrogen negative feedback were normal. Vglut2-ires-Cre;Esr1(lox/lox) mice were also infertile but displayed a wider range of deficits, including advanced puberty onset, abnormal negative feedback, and abolished positive feedback. Whereas <25% of preoptic kisspeptin neurons expressed Cre in Vgat- and Vglut2-ires-Cre lines, ∼70% of arcuate kisspeptin neurons were targeted in Vglut2-ires-Cre;Esr1(lox/lox) mice, possibly contributing to their advanced puberty phenotype. These observations show that, unexpectedly, ESR1-GABA neurons are only essential for the positive feedback mechanism. In contrast, we reveal the key importance of ESR1 in glutamatergic neurons for multiple estrogen feedback loops within the GnRH neuronal network required for fertility in the female mouse.
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Aromatase, estrogen receptors and brain development in fish and amphibians. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2014; 1849:152-62. [PMID: 25038582 DOI: 10.1016/j.bbagrm.2014.07.002] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Revised: 06/19/2014] [Accepted: 07/07/2014] [Indexed: 12/20/2022]
Abstract
Estrogens affect brain development of vertebrates, not only by impacting activity and morphology of existing circuits, but also by modulating embryonic and adult neurogenesis. The issue is complex as estrogens can not only originate from peripheral tissues, but also be locally produced within the brain itself due to local aromatization of androgens. In this respect, teleost fishes are quite unique because aromatase is expressed exclusively in radial glial cells, which represent pluripotent cells in the brain of all vertebrates. Expression of aromatase in the brain of fish is also strongly stimulated by estrogens and some androgens. This creates a very intriguing positive auto-regulatory loop leading to dramatic aromatase expression in sexually mature fish with elevated levels of circulating steroids. Looking at the effects of estrogens or anti-estrogens in the brain of adult zebrafish showed that estrogens inhibit rather than stimulate cell proliferation and newborn cell migration. The functional meaning of these observations is still unclear, but these data suggest that the brain of fish is experiencing constant remodeling under the influence of circulating steroids and brain-derived neurosteroids, possibly permitting a diversification of sexual strategies, notably hermaphroditism. Recent data in frogs indicate that aromatase expression is limited to neurons and do not concern radial glial cells. Thus, until now, there is no other example of vertebrates in which radial progenitors express aromatase. This raises the question of when and why these new features were gained and what are their adaptive benefits. This article is part of a Special Issue entitled: Nuclear receptors in animal development.
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Non-classical effects of estradiol on cAMP responsive element binding protein phosphorylation in gonadotropin-releasing hormone neurons: mechanisms and role. Front Neuroendocrinol 2014; 35:31-41. [PMID: 23978477 DOI: 10.1016/j.yfrne.2013.08.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Revised: 07/29/2013] [Accepted: 08/12/2013] [Indexed: 12/17/2022]
Abstract
Gonadotropin-releasing hormone (GnRH) is produced by a heterogenous neuronal population in the hypothalamus to control pituitary gonadotropin production and reproductive function in all mammalian species. Estradiol is a critical component for the communication between the gonads and the central nervous system. Resolving the mechanisms by which estradiol modulates GnRH neurons is critical for the understanding of how fertility is regulated. Extensive studies during the past decades have provided compelling evidence that estradiol has the potential to alter the intracellular signal transduction mechanisms. The common target of many signaling pathways is the phosphorylation of a key transcription factor, the cAMP response element binding protein (CREB). This review first addresses the aspects of estradiol action on CREB phosphorylation (pCREB) in GnRH neurons. Secondly, this review considers the receptors and signaling network that regulates estradiol's action on pCREB within GnRH neurons and finally it summarizes the physiological significance of CREB to estrogen feedback.
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Brock O, Bakker J. The two kisspeptin neuronal populations are differentially organized and activated by estradiol in mice. Endocrinology 2013; 154:2739-49. [PMID: 23744640 DOI: 10.1210/en.2013-1120] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In rodents, kisspeptin-expressing neurons are localized in 2 hypothalamic brain nuclei (anteroventral periventricular nucleus/periventricular nucleus continuum [AVPv/PeN] and arcuate nucleus [ARC]) and modulated by sex steroids. By using wild-type (WT) and aromatase knockout (ArKO) mice (which cannot convert testosterone into estradiol) and immunohistochemistry, we observed that WT females showed a continuous increase in kisspeptin peptide expression in the ARC across postnatal ages (postnatal day 5 [P5] to P25), whereas WT males did not show any expression before P25. Kisspeptin peptide expression was also present in ArKO females but did not increase over this early postnatal period, suggesting that kisspeptin peptide expression in the ARC is organized by estradiol-dependent and -independent mechanisms. We also compared kisspeptin peptide expression between groups of adult male and female mice that were left gonadally intact or gonadectomized and treated or not with estradiol (E(2)) or DHT. In the ARC, kisspeptin peptide expression decreased after gonadectomy but was completely rescued by either E(2) or DHT treatment in each sex/genotype. However, kisspeptin peptide expression was lower in ArKO compared with WT subjects. In the AVPv/PeN, ArKO females showed a male-typical kisspeptin peptide expression, and adult E(2) treatment partially restored kisspeptin peptide expression. Finally, we showed that, after E2 treatment of WT and ArKO mice between either P5 and P15 or P15 and P25, AVPv/PeN kisspeptin peptide expression could be still masculinized at P5, but was feminized from P15 onward. In conclusion, the 2 kisspeptin neuronal populations (AVPv/PeN vs ARC) seem to be differentially organized and activated by E(2).
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Affiliation(s)
- Olivier Brock
- Netherlands Institute for Neuroscience, 1105 BA Amsterdam, The Netherlands.
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Clarkson J. Effects of estradiol on kisspeptin neurons during puberty. Front Neuroendocrinol 2013; 34:120-31. [PMID: 23500175 DOI: 10.1016/j.yfrne.2013.02.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2012] [Revised: 02/22/2013] [Accepted: 02/25/2013] [Indexed: 11/24/2022]
Abstract
The activation of the gonadotropin-releasing hormone (GnRH) neurons from a state of relative quiescence is critical for initiating puberty in mammals. Kisspeptin and its G-protein coupled receptor Gpr54 are essential for puberty, with disruption to either resulting in failed puberty in humans and mice. Robust data from several species indicate that Kiss1 mRNA and/or kisspeptin peptide expression within the hypothalamus increases during pubertal development. Kisspeptin fiber innervation of GnRH neurons and kisspeptin release within the hypothalamus also increase during pubertal development, indicating that there is increased kisspeptinergic drive to GnRH neurons during pubertal development. It is becoming increasingly apparent that gonadal steroids play important roles in the regulation of kisspeptin expression during pubertal development, and in particular, estradiol signaling through estrogen receptor alpha appears to be necessary for these changes to occur. This review focuses on the role that estradiol plays in the regulation of kisspeptin expression during pubertal development.
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Affiliation(s)
- Jenny Clarkson
- Centre for Neuroendocrinology, Department of Physiology, School of Medical Sciences, University of Otago, Dunedin 9054, New Zealand.
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Franceschini I, Desroziers E. Development and Aging of the Kisspeptin-GPR54 System in the Mammalian Brain: What are the Impacts on Female Reproductive Function? Front Endocrinol (Lausanne) 2013; 4:22. [PMID: 23543285 PMCID: PMC3610010 DOI: 10.3389/fendo.2013.00022] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Accepted: 02/22/2013] [Indexed: 11/13/2022] Open
Abstract
The prominent role of the G protein coupled receptor GPR54 and its peptide ligand kisspeptin in the progression of puberty has been extensively documented in many mammalian species including humans. Kisspeptins are very potent gonadotropin-releasing hormone secretagogues produced by two main populations of neurons located in two ventral forebrain regions, the preoptic area and the arcuate nucleus. Within the last 2 years a substantial amount of data has accumulated concerning the development of these neuronal populations and their timely regulation by central and peripheral factors during fetal, neonatal, and peripubertal stages of development. This review focuses on the development of the kisspeptin-GPR54 system in the brain of female mice, rats, sheep, monkeys, and humans. We will also discuss the notion that this system represents a major target through which signals from the environment early in life can reprogram reproductive function.
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Affiliation(s)
- Isabelle Franceschini
- UMR85 Physiologie de la Reproduction et des Comportements, Institut National de Recherche AgronomiqueNouzilly, France
- UMR7247, Centre National de la Recherche ScientifiqueNouzilly, France
- Université François Rabelais de ToursTours, France
- Institut Français du Cheval et de l’EquitationNouzilly, France
- *Correspondence: Isabelle Franceschini, Centre INRA de Tours, Unité de Physiologie de la Reproduction et des Comportements, UMR 7247 INRA/CNRS/Univ. Tours/IFCE, 37380 Nouzilly, France. e-mail:
| | - Elodie Desroziers
- UMR85 Physiologie de la Reproduction et des Comportements, Institut National de Recherche AgronomiqueNouzilly, France
- UMR7247, Centre National de la Recherche ScientifiqueNouzilly, France
- Université François Rabelais de ToursTours, France
- Institut Français du Cheval et de l’EquitationNouzilly, France
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