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Cuervo Sánchez ML, Prado Spalm FH, Furland NE, Vallés AS. Pregestational fructose-induced metabolic syndrome in Wistar rats causes sexually dimorphic behavioral changes in their offspring. Dev Neurobiol 2024; 84:142-157. [PMID: 38664979 DOI: 10.1002/dneu.22940] [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] [Received: 11/28/2023] [Revised: 04/04/2024] [Accepted: 04/06/2024] [Indexed: 07/17/2024]
Abstract
Metabolic syndrome (MetS), marked by enduring metabolic inflammation, has detrimental effects on cognitive performance and brain structure, influencing behavior. This study aimed to investigate whether maternal MetS could negatively impact the neurodevelopment and metabolism of offspring. To test this hypothesis, 2 months old female Wistar rats were subjected to a 10-week regimen of tap water alone or supplemented with 20% fructose to induce MetS. Dams were mated with healthy males to generate litters: OC (offspring from control dams) and OMetS (offspring from dams with MetS). To isolate prenatal effects, all pups were breastfed by control nurse dams, maintaining a standard diet and water ad libitum until weaning. Behavioral assessments were conducted between postnatal days (PN) 22 and 95, and metabolic parameters were analyzed post-sacrifice on PN100. Results from the elevated plus maze, the open field, and the marble burying tests revealed a heightened anxiety-like phenotype in OMetS females. The novel object recognition test showed that exclusively OMetS males had long-term memory impairment. In the reciprocal social interaction test, OMetS displayed a lower number of social interactions, with a notable increase in "socially inactive" behavior observed exclusively in females. Additionally, in the three-chamber test, social preference and social novelty indexes were found to be lower solely among OMetS females. An increase in visceral fat concomitantly with hypertriglyceridemia was the relevant postmortem metabolic finding in OMetS females. In summary, maternal MetS leads to enduring damage and adverse effects on offspring neurobehavior and metabolism, with notable sexual dimorphism.
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Affiliation(s)
- Marié L Cuervo Sánchez
- Nutrition and Neurodevelopmental Laboratory, INIBIBB-CONICET-UNS, Bahía Blanca, Argentina
| | - Facundo H Prado Spalm
- Nutrition and Neurodevelopmental Laboratory, INIBIBB-CONICET-UNS, Bahía Blanca, Argentina
| | - Natalia E Furland
- Nutrition and Neurodevelopmental Laboratory, INIBIBB-CONICET-UNS, Bahía Blanca, Argentina
| | - Ana S Vallés
- Nutrition and Neurodevelopmental Laboratory, INIBIBB-CONICET-UNS, Bahía Blanca, Argentina
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2
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Bendis PC, Zimmerman S, Onisiforou A, Zanos P, Georgiou P. The impact of estradiol on serotonin, glutamate, and dopamine systems. Front Neurosci 2024; 18:1348551. [PMID: 38586193 PMCID: PMC10998471 DOI: 10.3389/fnins.2024.1348551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2023] [Accepted: 02/22/2024] [Indexed: 04/09/2024] Open
Abstract
Estradiol, the most potent and prevalent member of the estrogen class of steroid hormones and is expressed in both sexes. Functioning as a neuroactive steroid, it plays a crucial role in modulating neurotransmitter systems affecting neuronal circuits and brain functions including learning and memory, reward and sexual behaviors. These neurotransmitter systems encompass the serotonergic, dopaminergic, and glutamatergic signaling pathways. Consequently, this review examines the pivotal role of estradiol and its receptors in the regulation of these neurotransmitter systems in the brain. Through a comprehensive analysis of current literature, we investigate the multifaceted effects of estradiol on key neurotransmitter signaling systems, namely serotonin, dopamine, and glutamate. Findings from rodent models illuminate the impact of hormone manipulations, such as gonadectomy, on the regulation of neuronal brain circuits, providing valuable insights into the connection between hormonal fluctuations and neurotransmitter regulation. Estradiol exerts its effects by binding to three estrogen receptors: estrogen receptor alpha (ERα), estrogen receptor beta (ERβ), and G protein-coupled receptor (GPER). Thus, this review explores the promising outcomes observed with estradiol and estrogen receptor agonists administration in both gonadectomized and/or genetically knockout rodents, suggesting potential therapeutic avenues. Despite limited human studies on this topic, the findings underscore the significance of translational research in bridging the gap between preclinical findings and clinical applications. This approach offers valuable insights into the complex relationship between estradiol and neurotransmitter systems. The integration of evidence from neurotransmitter systems and receptor-specific effects not only enhances our understanding of the neurobiological basis of physiological brain functioning but also provides a comprehensive framework for the understanding of possible pathophysiological mechanisms resulting to disease states. By unraveling the complexities of estradiol's impact on neurotransmitter regulation, this review contributes to advancing the field and lays the groundwork for future research aimed at refining understanding of the relationship between estradiol and neuronal circuits as well as their involvement in brain disorders.
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Affiliation(s)
- Peyton Christine Bendis
- Psychoneuroendocrinology Laboratory, Department of Psychology, University of Wisconsin Milwaukee, Milwaukee, WI, United States
| | - Sydney Zimmerman
- Psychoneuroendocrinology Laboratory, Department of Psychology, University of Wisconsin Milwaukee, Milwaukee, WI, United States
| | - Anna Onisiforou
- Translational Neuropharmacology Laboratory, Department of Psychology, University of Cyprus, Nicosia, Cyprus
| | - Panos Zanos
- Translational Neuropharmacology Laboratory, Department of Psychology, University of Cyprus, Nicosia, Cyprus
| | - Polymnia Georgiou
- Psychoneuroendocrinology Laboratory, Department of Psychology, University of Wisconsin Milwaukee, Milwaukee, WI, United States
- Laboratory of Epigenetics and Gene Regulation, Department of Biological Sciences, University of Cyprus, Nicosia, Cyprus
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McGill CJ, Christensen A, Qian W, Thorwald MA, Lugo JG, Namvari S, White OS, Finch CE, Benayoun BA, Pike CJ. Protection against APOE4 -associated aging phenotypes with the longevity-promoting intervention 17α-estradiol in male mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.12.584678. [PMID: 38559059 PMCID: PMC10980056 DOI: 10.1101/2024.03.12.584678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
The apolipoprotein ε4 allele ( APOE4 ) is associated with decreased longevity, increased vulnerability to age-related declines, and disorders across multiple systems. Interventions that promote healthspan and lifespan represent a promising strategy to attenuate the development of APOE4 -associated aging phenotypes. Here we studied the ability of the longevity-promoting intervention 17α-estradiol (17αE2) to protect against age-related impairments in APOE4 versus the predominant APOE3 genotype using early middle-aged mice with knock-in of human APOE alleles. Beginning at age 10 months, male APOE3 or APOE4 mice were treated for 20 weeks with 17αE2 or vehicle then compared for indices of aging phenotypes body-wide. Across peripheral and neural measures, APOE4 was associated with poorer outcomes. Notably, 17αE2 treatment improved outcomes in a genotype-dependent manner favoring APOE4 mice. These data demonstrate a positive APOE4 bias in 17αE2-mediated healthspan actions, suggesting that longevity-promoting interventions may be useful in mitigating deleterious age-related risks associated with APOE4 genotype.
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Shakya R, Amonruttanapun P, Limboonreung T, Chongthammakun S. 17β-estradiol mitigates the inhibition of SH-SY5Y cell differentiation through WNT1 expression. Cells Dev 2023; 176:203881. [PMID: 37914154 DOI: 10.1016/j.cdev.2023.203881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 10/01/2023] [Accepted: 10/27/2023] [Indexed: 11/03/2023]
Abstract
17β-estradiol (E2) and canonical WNT-signaling represent crucial regulatory pathways for microtubule dynamics and synaptic formation. However, it is unclear yet whether E2-induced canonical WNT ligands have significant impact on neurogenic repair under inflammatory condition. In this study, first, we prepared the chronic activated-microglial-conditioned media, known to be comprised of neuro-inflammatory components. Long term exposure of microglial conditioned media to SH-SY5Y cells showed a negative impact on differentiation markers, microtubule associated protein-2 (MAP2) and synaptophysin (SYP), which was successfully rescued by pre and co-treatment of 10 nM 17β-estradiol. The inhibition of estrogen receptors, ERα and ERβ significantly blocked the E2-mediated recovery in the expression of differentiation marker, SYP. Furthermore, the inflammatory inhibition of canonical signaling ligand, WNT1 was also found to be rescued by E2. To our surprise, E2 was unable to replicate this success with β-catenin, which is considered to be the intracellular transducer of canonical WNT signaling. However, WNT antagonist - Dkk1 blocked the E2-mediated recovery in the expression of the differentiation marker, MAP2. Therefore, our data suggests that E2-mediated recovery in SH-SY5Y differentiation follows a divergent pathway from the conventional canonical WNT signaling pathway, which seems to regulate microtubule stability without the involvement of β-catenin. This mechanism provides fresh insight into how estradiol contributes to the restoration of differentiation marker proteins in the context of chronic neuroinflammation.
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Affiliation(s)
- Rubina Shakya
- Department of Anatomy and Center for Neuroscience Faculty of Science, Mahidol University, Bangkok 10400, Thailand; Department of Anatomy, Kathmandu University, School of Medical Sciences, Dhulikhel, Kavre 11008, Nepal.
| | - Prateep Amonruttanapun
- Chulabhorn International College of Medicine, Thammasat University, Rangsit Campus, Pathumthani 12121, Thailand.
| | - Tanapol Limboonreung
- Department of Oral Biology, Faculty of Dentistry, King Mongkut's Institute of Technology Ladkrabang, Ladkrabang, Bangkok 10520, Thailand.
| | - Sukumal Chongthammakun
- Department of Anatomy and Center for Neuroscience Faculty of Science, Mahidol University, Bangkok 10400, Thailand
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Sheppard PAS, Chandramohan D, Lumsden A, Vellone D, Denley MCS, Srivastava DP, Choleris E. Social memory in female mice is rapidly modulated by 17β-estradiol through ERK and Akt modulation of synapse formation. Proc Natl Acad Sci U S A 2023; 120:e2300191120. [PMID: 37490537 PMCID: PMC10400940 DOI: 10.1073/pnas.2300191120] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 05/25/2023] [Indexed: 07/27/2023] Open
Abstract
Social memory is essential to the functioning of a social animal within a group. Estrogens can affect social memory too quickly for classical genomic mechanisms. Previously, 17β-estradiol (E2) rapidly facilitated short-term social memory and increased nascent synapse formation, these synapses being potentiated following neuronal activity. However, what mechanisms underlie and coordinate the rapid facilitation of social memory and synaptogenesis are unclear. Here, the necessity of extracellular signal-regulated kinase (ERK) and phosphoinositide 3-kinase (PI3K) signaling for rapid facilitation of short-term social memory and synaptogenesis was tested. Mice performed a short-term social memory task or were used as task-naïve controls. ERK and PI3K pathway inhibitors were infused intradorsal hippocampally 5 min before E2 infusion. Forty minutes following intrahippocampal E2 or vehicle administration, tissues were collected for quantification of glutamatergic synapse number in the CA1. Dorsal hippocampal E2 rapid facilitation of short-term social memory depended upon ERK and PI3K pathways. E2 increased glutamatergic synapse number (bassoon puncta positive for GluA1) in task-performing mice but decreased synapse number in task-naïve mice. Critically, ERK signaling was required for synapse formation/elimination in task-performing and task-naïve mice, whereas PI3K inhibition blocked synapse formation only in task-performing mice. While ERK and PI3K are both required for E2 facilitation of short-term social memory and synapse formation, only ERK is required for synapse elimination. This demonstrates previously unknown, bidirectional, rapid actions of E2 on brain and behavior and underscores the importance of estrogen signaling in the brain to social behavior.
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Affiliation(s)
- Paul A. S. Sheppard
- Department of Psychology and Neuroscience Program, University of Guelph, Guelph, ONN1G 2W1, Canada
| | - Deepthi Chandramohan
- Department of Basic and Clinical Neuroscience, Maurice Wohl Clinical Neuroscience Institute, King’s College London, LondonWC2R 2LS, United Kingdom
- Medical Research Council Centre for Neurodevelopmental Disorders, King’s College London, LondonWC2R 2LS, United Kingdom
| | - Alanna Lumsden
- Department of Psychology and Neuroscience Program, University of Guelph, Guelph, ONN1G 2W1, Canada
| | - Daniella Vellone
- Department of Psychology and Neuroscience Program, University of Guelph, Guelph, ONN1G 2W1, Canada
| | - Matthew C. S. Denley
- Department of Basic and Clinical Neuroscience, Maurice Wohl Clinical Neuroscience Institute, King’s College London, LondonWC2R 2LS, United Kingdom
- Medical Research Council Centre for Neurodevelopmental Disorders, King’s College London, LondonWC2R 2LS, United Kingdom
| | - Deepak P. Srivastava
- Department of Basic and Clinical Neuroscience, Maurice Wohl Clinical Neuroscience Institute, King’s College London, LondonWC2R 2LS, United Kingdom
- Medical Research Council Centre for Neurodevelopmental Disorders, King’s College London, LondonWC2R 2LS, United Kingdom
| | - Elena Choleris
- Department of Psychology and Neuroscience Program, University of Guelph, Guelph, ONN1G 2W1, Canada
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Frankfurt M, Nassrallah Z, Luine V. Steroid Hormone Interaction with Dendritic Spines: Implications for Neuropsychiatric Disease. ADVANCES IN NEUROBIOLOGY 2023; 34:349-366. [PMID: 37962800 DOI: 10.1007/978-3-031-36159-3_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Dendritic spines, key sites for neural plasticity, are influenced by gonadal steroids. In this chapter, we review the effects of gonadal steroids on dendritic spine density in areas important to cognitive function, the hippocampus, and prefrontal cortex. Most of these animal model studies investigated the effects of estrogen in females, but we also include more recent data on androgen effects in both males and females. The underlying genomic and non-genomic mechanisms related to gonadal steroid-induced spinogenesis are also reviewed. Subsequently, we discuss possible reasons for the observed sex differences in many neuropsychiatric diseases, which appear to be caused, in part, by aberrant synaptic connections that may involve dendritic spine pathology. Overall, knowledge concerning the regulation of dendritic spines by gonadal hormones has grown since the initial discoveries in the 1990s, and current research points to a potential role for aberrant spine functioning in many neuropsychiatric disorders.
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Affiliation(s)
- Maya Frankfurt
- Hofstra Northwell School of Nursing and Physician Assistant Studies, Hempstead, NY, USA.
| | - Zeinab Nassrallah
- Department of Science Education Zucker School of Medicine, 500 Hofstra University, Hempstead, NY, USA
| | - Victoria Luine
- Department of Psychology, Hunter College, New York, NY, USA
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Bosakova T, Tockstein A, Bosakova Z, Komrskova K. Kinetic Study of 17α-Estradiol Mechanism during Rat Sperm Capacitation. Molecules 2022; 27:molecules27134092. [PMID: 35807338 PMCID: PMC9268409 DOI: 10.3390/molecules27134092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 06/13/2022] [Accepted: 06/23/2022] [Indexed: 02/01/2023] Open
Abstract
17α-Estradiol (αE2) is a natural diastereoisomer of 17β-estradiol (E2). It is well known that αE2 can bind to estrogen receptors. However, its biological activity is less than that of E2 and is species and tissue specific. The goal of our study was to propose the mechanism of αE2 hormonal response in rat sperm during their capacitation in vitro and compare it with a previously studied mouse model. Concentration changes in externally added αE2 during capacitation of rat sperm were monitored by the high-performance liquid chromatographic method with tandem mass spectrometric detection (HPLC-MS/MS). The calculated values of relative concentrations Bt were subjected to kinetic analysis. The findings indicated that αE2 in rat sperm did not trigger autocatalytic reaction, in contrast to the mouse sperm, and that the initiation of the hormone penetration through the sperm plasma membrane was substantially faster in rats.
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Affiliation(s)
- Tereza Bosakova
- Department of Analytical Chemistry, Faculty of Science, Charles University, Albertov 2030, Prague 2, 128 43 Prague, Czech Republic; (T.B.); (A.T.)
- Laboratory of Reproductive Biology, Institute of Biotechnology, Czech Academy of Sciences, BIOCEV, Prumyslova 595, 252 50 Vestec, Czech Republic
| | - Antonin Tockstein
- Department of Analytical Chemistry, Faculty of Science, Charles University, Albertov 2030, Prague 2, 128 43 Prague, Czech Republic; (T.B.); (A.T.)
| | - Zuzana Bosakova
- Department of Analytical Chemistry, Faculty of Science, Charles University, Albertov 2030, Prague 2, 128 43 Prague, Czech Republic; (T.B.); (A.T.)
- Correspondence: (Z.B.); (K.K.); Tel.: +420-221951231 (Z.B.); +420-604855871 (K.K.)
| | - Katerina Komrskova
- Laboratory of Reproductive Biology, Institute of Biotechnology, Czech Academy of Sciences, BIOCEV, Prumyslova 595, 252 50 Vestec, Czech Republic
- Department of Zoology, Faculty of Science, Charles University, Vinicna 7, Prague 2, 128 44 Prague, Czech Republic
- Correspondence: (Z.B.); (K.K.); Tel.: +420-221951231 (Z.B.); +420-604855871 (K.K.)
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Luine V, Mohan G, Attalla S, Jacome L, Frankfurt M. Androgens Enhance Recognition Memory and Dendritic Spine Density in the Hippocampus and Prefrontal Cortex of Ovariectomized Female Rats. Neuroscience 2022:S0306-4522(22)00287-1. [PMID: 35671881 PMCID: PMC9719572 DOI: 10.1016/j.neuroscience.2022.06.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 05/28/2022] [Accepted: 06/01/2022] [Indexed: 12/28/2022]
Abstract
Estrogen replacement has been repeatedly shown to enhance memory and increase dendritic spine density in the hippocampus and prefrontal cortex of ovariectomized (OVX) female rats. Given the potential deleterious effects of chronic estrogen administration, the present study assessed cognitive function using recognition memory tasks and measured dendritic spine density in the CA1 region of the hippocampus and medial prefrontal cortex after subchronic androgen replacement to adult OVX female rats. All androgens enhanced recognition memory in OVX rats, but object placement (OP) and object recognition (OR) results differed. Only testosterone enhanced OR. Testosterone had no effect on OP while dehydroepiandrosterone (DHEA), dihydrotestosterone (DHT) and androstenedione (AD) enhanced OP. Dendritic spine density was increased by both TP and DHEA in both brain areas (DHT and AD were not tested). Lastly, we used the aromatase inhibitor, letrozole, to discriminate between potential androgenic and estrogenic effects of androgens on behavior. Letrozole alone did not alter recognition memory in OVX rats and did not block the effects of either TP or DHEA on recognition memory suggesting that effects were mediated via androgenic mechanisms. The present results expand previous information on gonadal hormone actions and show that, in addition to estrogens, androgens also improve memory and increase spine density in brains of OVX female rats. While requiring further investigation, these observations provide a basis for therapeutic interventions in the treatment of menopausal, age or disease related memory loss.
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Affiliation(s)
- Victoria Luine
- Department of Psychology, Hunter College, 695 Park Avenue, New York, NY 10065, United States.
| | - Govini Mohan
- Department of Psychology, Hunter College, 695 Park Avenue, New York, NY 10065, United States
| | - Sara Attalla
- Department of Psychology, Hunter College, 695 Park Avenue, New York, NY 10065, United States
| | - Luis Jacome
- Department of Psychology, Hunter College, 695 Park Avenue, New York, NY 10065, United States
| | - Maya Frankfurt
- Hofstra Northwell School of Nursing and Physician Assistant Studies, 160 Hofstra University, 400A Shapiro Family Hall, Hempstead, NY 11549, United States
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9
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Chen H, Zhang X, Xu C, An S, Ma XM, Qiao H. Endogenous Hippocampal Estrogen Is Involved in Stress-induced Depression-like Behaviors and Spine Plasticity in Male Rats. Neurosci Lett 2022; 785:136560. [DOI: 10.1016/j.neulet.2022.136560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 01/20/2022] [Accepted: 02/25/2022] [Indexed: 10/19/2022]
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Beamish SB, Frick KM. A Putative Role for Ubiquitin-Proteasome Signaling in Estrogenic Memory Regulation. Front Behav Neurosci 2022; 15:807215. [PMID: 35145382 PMCID: PMC8821141 DOI: 10.3389/fnbeh.2021.807215] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 12/20/2021] [Indexed: 12/31/2022] Open
Abstract
Sex steroid hormones such as 17β-estradiol (E2) are critical neuromodulators of hippocampal synaptic plasticity and hippocampus-dependent memory in both males and females. However, the mechanisms through which E2 regulates memory formation in both sexes remain unclear. Research to date suggests that E2 regulates hippocampus-dependent memory by activating numerous cell-signaling cascades to promote the synthesis of proteins that support structural changes at hippocampal synapses. However, this work has largely overlooked the equally important contributions of protein degradation mediated by the ubiquitin proteasome system (UPS) in remodeling the synapse. Despite being critically implicated in synaptic plasticity and successful formation of long-term memories, it remains unclear whether protein degradation mediated by the UPS is necessary for E2 to exert its beneficial effects on hippocampal plasticity and memory formation. The present article provides an overview of the receptor and signaling mechanisms so far identified as critical for regulating hippocampal E2 and UPS function in males and females, with a particular emphasis on the ways in which these mechanisms overlap to support structural integrity and protein composition of hippocampal synapses. We argue that the high degree of correspondence between E2 and UPS activity warrants additional study to examine the contributions of ubiquitin-mediated protein degradation in regulating the effects of sex steroid hormones on cognition.
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Sheppard PAS, Puri TA, Galea LAM. Sex Differences and Estradiol Effects in MAPK and Akt Cell Signaling across Subregions of the Hippocampus. Neuroendocrinology 2022; 112:621-635. [PMID: 34407537 DOI: 10.1159/000519072] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 08/16/2021] [Indexed: 11/19/2022]
Abstract
INTRODUCTION Rapid effects of estrogens within the hippocampus of rodents are dependent upon cell-signaling cascades, and activation of these cascades by estrogens varies by sex. Whether these pathways are rapidly activated within the dentate gyrus (DG) and CA1 by estrogens across sex and the anatomical longitudinal axis has been overlooked. METHODS Gonadally intact female and male rats were given either vehicle or physiological systemic low (1.1 µg/kg) or high (37.3 µg/kg) doses of 17β-estradiol 30 min prior to tissue collection. To control for the effects of circulating estrogens, an additional group of female rats was ovariectomized (OVX) and administered 17β-estradiol. Brains were extracted, and tissue punches of the CA1 and DG were taken along the longitudinal hippocampal axis (dorsal and ventral) and analyzed for key mitogen-activated protein kinase (MAPK) and protein kinase B (Akt) cascade phosphoproteins. RESULTS Intact females had higher Akt pathway phosphoproteins (pAkt, pGSK-3β, and pp70S6K) than males in the DG (dorsal and ventral) and lower pERK1/2 in the dorsal DG. Most effects of 17β-estradiol on cell signaling occurred in OVX animals. In OVX animals, 17β-estradiol increased cell signaling of MAPK and Akt phosphoproteins (pERK1/2, pJNK, pAkt, and pGSK-3β) in the CA1 and pERK1/2 and pJNK DG. DISCUSSION/CONCLUSIONS Systemic 17β-estradiol treatment rapidly alters phosphoprotein levels in the hippocampus, dependent on reproductive status, and intact females have greater expression of Akt phosphoproteins than that in intact males in the DG. These findings shed light on underlying mechanisms of sex differences in hippocampal function and response to interventions that affect MAPK or Akt signaling.
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Affiliation(s)
- Paul A S Sheppard
- Department of Psychology, University of British Columbia, Vancouver, British Columbia, Canada
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, British Columbia, Canada
| | - Tanvi A Puri
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, British Columbia, Canada
- Graduate Program in Neuroscience, University of British Columbia, Vancouver, British Columbia, Canada
| | - Liisa A M Galea
- Department of Psychology, University of British Columbia, Vancouver, British Columbia, Canada
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, British Columbia, Canada
- Graduate Program in Neuroscience, University of British Columbia, Vancouver, British Columbia, Canada
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Perez-Rando M, Guirado R, Tellez-Merlo G, Carceller H, Nacher J. Estradiol Regulates Polysialylated Form of the Neural Cell Adhesion Molecule Expression and Connectivity of O-LM Interneurons in the Hippocampus of Adult Female Mice. Neuroendocrinology 2022; 112:51-67. [PMID: 33550289 DOI: 10.1159/000515052] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Accepted: 02/04/2021] [Indexed: 11/19/2022]
Abstract
The estrous cycle is caused by the changing concentration of ovarian hormones, particularly 17β-estradiol, a hormone whose effect on excitatory circuits has been extensively reported. However, fewer studies have tried to elucidate how this cycle, or this hormone, affects the plasticity of inhibitory networks and the structure of interneurons. Among these cells, somatostatin-expressing O-LM neurons of the hippocampus are especially interesting. They have a role in the modulation of theta oscillations, and they receive direct input from the entorhinal cortex, which place them in the center of hippocampal function. In this study, we report that the expression of polysialylated form of the neural cell adhesion molecule (PSA-NCAM) in the hippocampus, a molecule involved in the plasticity of somatostatin-expressing interneurons in the adult brain, fluctuated through the different stages of the estrous cycle. Likewise, these stages and the expression of PSA-NCAM affected the density of dendritic spines of O-LM cells. We also describe that 17β-estradiol replacement of adult ovariectomized female mice caused an increase in the perisomatic inhibitory puncta in O-LM interneurons as well as an increase in their axonal bouton density. Interestingly, this treatment also induced a decrease in their dendritic spine density, specifically in O-LM interneurons lacking PSA-NCAM expression. Finally, using an ex vivo real-time assay with entorhinal-hippocampal organotypic cultures, we show that this hormone decreased the dynamics in spinogenesis, altogether highlighting the modulatory effect that 17β-estradiol has on inhibitory circuits.
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Affiliation(s)
- Marta Perez-Rando
- Neurobiology Unit, Program in Neurosciences and BIOTECMED Institute, Universitat de València, Burjassot, Spain
- Fundación Investigación Hospital Clínico de Valencia, INCLIVA, Valencia, Spain
| | - Ramon Guirado
- Neurobiology Unit, Program in Neurosciences and BIOTECMED Institute, Universitat de València, Burjassot, Spain
- Fundación Investigación Hospital Clínico de Valencia, INCLIVA, Valencia, Spain
- Dirección General de Universidades, Gobierno de Aragón, Zaragoza, Spain
| | - Guillermina Tellez-Merlo
- Lab. Neuropsiquiatría, Instituto de Fisiología, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
- Departamento de Fisiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Ciudad de México, Mexico
| | - Hector Carceller
- Neurobiology Unit, Program in Neurosciences and BIOTECMED Institute, Universitat de València, Burjassot, Spain
| | - Juan Nacher
- Neurobiology Unit, Program in Neurosciences and BIOTECMED Institute, Universitat de València, Burjassot, Spain
- Fundación Investigación Hospital Clínico de Valencia, INCLIVA, Valencia, Spain
- CIBERSAM: Spanish National Network for Research in Mental Health, Valencia, Spain
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Navakkode S, Gaunt JR, Pavon MV, Bansal VA, Abraham RP, Chong YS, Ch'ng TH, Sajikumar S. Sex-specific accelerated decay in time/activity-dependent plasticity and associative memory in an animal model of Alzheimer's disease. Aging Cell 2021; 20:e13502. [PMID: 34796608 PMCID: PMC8672784 DOI: 10.1111/acel.13502] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 09/02/2021] [Accepted: 10/17/2021] [Indexed: 12/11/2022] Open
Abstract
Clinical studies have shown that female brains are more predisposed to neurodegenerative diseases such as Alzheimer's disease (AD), but the cellular and molecular mechanisms behind this disparity remain unknown. In several mouse models of AD, synaptic plasticity dysfunction is an early event and appears before significant accumulation of amyloid plaques and neuronal degeneration. However, it is unclear whether sexual dimorphism at the synaptic level contributes to the higher risk and prevalence of AD in females. Our studies on APP/PS1 (APPSwe/PS1dE9) mouse model show that AD impacts hippocampal long‐term plasticity in a sex‐specific manner. Long‐term potentiation (LTP) induced by strong tetanic stimulation (STET), theta burst stimulation (TBS) and population spike timing‐dependent plasticity (pSTDP) show a faster decay in AD females compared with age‐matched AD males. In addition, behavioural tagging (BT), a model of associative memory, is specifically impaired in AD females with a faster decay in memory compared with males. Together with the plasticity and behavioural data, we also observed an upregulation of neuroinflammatory markers, along with downregulation of transcripts that regulate cellular processes associated with synaptic plasticity and memory in females. Immunohistochemistry of AD brains confirms that female APP/PS1 mice carry a higher amyloid plaque burden and have enhanced microglial activation compared with male APP/PS1 mice. Their presence in the diseased mice also suggests a link between the impairment of LTP and the upregulation of the inflammatory response. Overall, our data show that synaptic plasticity and associative memory impairments are more prominent in females and this might account for the faster progression of AD in females.
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Affiliation(s)
- Sheeja Navakkode
- Lee Kong Chian School of Medicine Nanyang Technological University Singapore Singapore
- Department of Physiology National University of Singapore Singapore Singapore
| | - Jessica Ruth Gaunt
- Lee Kong Chian School of Medicine Nanyang Technological University Singapore Singapore
| | - Maria Vazquez Pavon
- Department of Physiology National University of Singapore Singapore Singapore
| | | | - Riya Prasad Abraham
- Department of Physiology National University of Singapore Singapore Singapore
| | - Yee Song Chong
- Department of Physiology National University of Singapore Singapore Singapore
| | - Toh Hean Ch'ng
- Lee Kong Chian School of Medicine Nanyang Technological University Singapore Singapore
- School of Biological Science Nanyang Technological University Singapore Singapore
| | - Sreedharan Sajikumar
- Department of Physiology National University of Singapore Singapore Singapore
- Healthy Longevity Translational Research Programme Yong Loo Lin School of Medicine National University of Singapore Singapore Singapore
- Life Sciences Institute Neurobiology Programme National University of Singapore Singapore Singapore
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14
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Estrogenic hormones receptors in Alzheimer's disease. Mol Biol Rep 2021; 48:7517-7526. [PMID: 34657250 DOI: 10.1007/s11033-021-06792-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 09/15/2021] [Indexed: 02/06/2023]
Abstract
Estrogens are hormones that play a critical role during development and growth for the adequate functioning of the reproductive system of women, as well as for maintaining bones, metabolism, and cognition. During menopause, the levels of estrogens are decreased, altering their signaling mediated by their intracellular receptors such as estrogen receptor alpha and beta (ERα and ERβ), and G protein-coupled estrogen receptor (GPER). In the brain, the reduction of molecular pathways mediated by estrogenic receptors seems to favor the progression of Alzheimer's disease (AD) in postmenopausal women. In this review, we investigate the participation of estrogen receptors in AD in women during aging.
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15
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Xu H, Yu ZH, Ge MJ, Shen JX, Han F, Pan C, Chen JJ, Zhu XL, Hou WY, Hou YQ, Lu YP. Estradiol attenuates chronic restraint stress-induced dendrite and dendritic spine loss and cofilin1 activation in ovariectomized mice. Horm Behav 2021; 135:105040. [PMID: 34358948 DOI: 10.1016/j.yhbeh.2021.105040] [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: 01/20/2021] [Revised: 07/18/2021] [Accepted: 07/22/2021] [Indexed: 10/20/2022]
Abstract
Ovarian hormone deprivation is associated with mood disorders, such as depression, and estradiol therapy is significantly more effective than placebos in treating major depression associated with menopause onset. However, the effect of estradiol on neuronal plasticity and its mechanisms remain to be further elucidated. In this study, behavioral assessments were used to examine the antidepressant effect of estradiol in ovariectomized (OVX) B6.Cg-TgN (Thy-YFP-H)-2Jrs transgenic mice on chronic restraint stress (CRS)-induced dendrite and dendritic spine loss; Yellow fluorescent protein (YFP) is characteristically expressed in excitatory neurons in transgenic mice, and its three-dimensional images were used to evaluate the effect of estradiol on the density of different types of dendritic spines. Quantification and distribution of cofilin1 and p-cofilin1 were determined by qPCR, Western blots, and immunohistochemistry, respectively. The results revealed that treatment with estradiol or clomipramine significantly improved depression-like behaviors. Estradiol treatment also significantly upregulated the dendritic density in all areas examined and increased the density of filopodia-type, thin-type and mushroom-type spines in the hippocampal CA1 and elevated the thin-type and mushroom-type spine density in the PFC. Consistent with these changes, estradiol treatment significantly increased the density of p-cofilin1 immunopositive dendritic spines. Thus, these data reveal a possible estradiol antidepressant mechanism, in that estradiol promoted the phosphorylation of cofilin1 and reduced the loss of dendrites and dendritic spines, which of these dendritic spines include not only immature spines such as filopodia-type, but also mature spines such as mushroom-type, and attenuated the depression-like behavior.
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Affiliation(s)
- Hui Xu
- College of Life Science, Anhui Normal University, No. 1 Beijing East Road, Wuhu 241000, China; Anhui College of Traditional Chinese Medicine, No. 18 Wuxiashan West Road, Wuhu 241002, China
| | - Zong-Hao Yu
- College of Life Science, Anhui Normal University, No. 1 Beijing East Road, Wuhu 241000, China
| | - Ming-Jun Ge
- College of Life Science, Anhui Normal University, No. 1 Beijing East Road, Wuhu 241000, China
| | - Jun-Xian Shen
- College of Life Science, Anhui Normal University, No. 1 Beijing East Road, Wuhu 241000, China
| | - Fei Han
- College of Life Science, Anhui Normal University, No. 1 Beijing East Road, Wuhu 241000, China
| | - Chuan Pan
- College of Life Science, Anhui Normal University, No. 1 Beijing East Road, Wuhu 241000, China
| | - Jing-Jing Chen
- College of Life Science, Anhui Normal University, No. 1 Beijing East Road, Wuhu 241000, China
| | - Xiu-Ling Zhu
- College of Life Science, Anhui Normal University, No. 1 Beijing East Road, Wuhu 241000, China; Department of Anatomy, Wannan Medical College, No. 22 Wenchang West Road, Wuhu 241002, China
| | - Wen-Yu Hou
- College of Life Science, Anhui Normal University, No. 1 Beijing East Road, Wuhu 241000, China
| | - Yu-Qiao Hou
- College of Life Science, Anhui Normal University, No. 1 Beijing East Road, Wuhu 241000, China
| | - Ya-Ping Lu
- College of Life Science, Anhui Normal University, No. 1 Beijing East Road, Wuhu 241000, China.
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16
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Li X, Johann S, Rune GM, Bender RA. Sex-specific Regulation of Spine Density and Synaptic Proteins by G-protein-coupled Estrogen Receptor (GPER)1 in Developing Hippocampus. Neuroscience 2021; 472:35-50. [PMID: 34364953 DOI: 10.1016/j.neuroscience.2021.07.035] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Revised: 07/28/2021] [Accepted: 07/29/2021] [Indexed: 11/19/2022]
Abstract
G-protein-coupled-estrogen-receptor 1 (GPER1) is a membrane-bound receptor that mediates estrogen signaling via intracellular signaling cascades. We recently showed that GPER1 promotes the distal dendritic enrichment of hyperpolarization activated and cyclic nucleotide-gated (HCN)1 channels in CA1 stratum lacunosum-moleculare (SLM), suggesting a role of GPER1-mediated signaling in neuronal plasticity. Here we studied whether this role involves processes of structural plasticity, such as the regulation of spine and synapse density in SLM. In organotypic entorhino-hippocampal cultures from mice expressing eGFP, we analyzed spine densities in SLM after treatment with GPER1 agonist G1 (20 nM). G1 significantly increased the density of "non-stubby" spines (maturing spines with a spine head and a neck), but did so only in cultures from female mice. In support of this finding, the expression of synaptic proteins was sex-specifically altered in the cultures: G1 increased the protein (but not mRNA) expression of PSD95 and reduced the p-/n-cofilin ratio only in cultures from females. Application of E2 (2 nM) reproduced the sex-specific effect on spine density in SLM, but only partially on the expression of synaptic proteins. Spine synapse density was, however, not altered after G1-treatment, suggesting that the increased spine density did not translate into an increased spine synapse density in the culture model. Taken together, our results support a role of GPER1 in mediating structural plasticity in CA1 SLM, but suggest that in developing hippocampus, this role is sex-specific.
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Affiliation(s)
- Xiaoyu Li
- Institute of Neuroanatomy, University Medical Center Hamburg, 20246 Hamburg, Germany
| | - Sonja Johann
- Institute of Neuroanatomy, University Medical Center Hamburg, 20246 Hamburg, Germany
| | - Gabriele M Rune
- Institute of Neuroanatomy, University Medical Center Hamburg, 20246 Hamburg, Germany
| | - Roland A Bender
- Institute of Neuroanatomy, University Medical Center Hamburg, 20246 Hamburg, Germany.
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17
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Sheppard PAS, Asling HA, Walczyk-Mooradally A, Armstrong SE, Elad VM, Lalonde J, Choleris E. Protein synthesis and actin polymerization in the rapid effects of 17β-estradiol on short-term social memory and dendritic spine dynamics in female mice. Psychoneuroendocrinology 2021; 128:105232. [PMID: 33892375 DOI: 10.1016/j.psyneuen.2021.105232] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 03/04/2021] [Accepted: 04/10/2021] [Indexed: 11/28/2022]
Abstract
Estrogens rapidly facilitate learning and memory, including social recognition - the ability of an animal to recognize another. In ovariectomized female mice, systemic or dorsal hippocampal administration of 17β-estradiol (E2) facilitates short-term social recognition memory within 40 min. Within the same timeframe, E2 increases dendritic spine density in CA1 dorsal hippocampal neurons of behavioural task-naïve mice and in hippocampal sections. Mechanisms underlying these effects remain unclear. Estrogens rapidly modulate actin cytoskeletal dynamics through actin polymerization and the translation of key synaptic proteins. We first determined doses of actin polymerization inhibitor latrunculin A (LAT) and protein synthesis inhibitor anisomycin (ANI) that would block short-term social recognition memory when infused into the dorsal hippocampus of ovariectomized female mice 15 min prior to testing. The highest doses that did not block social recognition prevented the facilitating effects of E2, whereas DNA transcription inhibitor, actinomycin D, could not block social recognition. As task performance may interfere with E2-facilitated increases in dendritic spine density, dendritic spine density and length were examined in task-performing and task-naïve mice. E2 increased dendritic spine density 15 but not 40 min following treatment, regardless of whether the animal had performed the social recognition task. This effect was blocked by LAT, but not ANI. Thus, both actin polymerization and protein synthesis are necessary for E2 to rapidly facilitate social recognition, whereas actin polymerization, but not protein synthesis, is required for the rapid increase in dendritic spine density brought on by E2.
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Affiliation(s)
- Paul A S Sheppard
- Department of Psychology and Neuroscience Program, University of Guelph, Guelph, ON, Canada
| | - Hayley A Asling
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada
| | | | - Sabrina E Armstrong
- Department of Psychology and Neuroscience Program, University of Guelph, Guelph, ON, Canada
| | - Vissy M Elad
- Department of Human Health and Nutrition Sciences, University of Guelph, Guelph, ON, Canada; Department of Biomedical Sciences, University of Guelph, Guelph, ON, Canada
| | - Jasmin Lalonde
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada
| | - Elena Choleris
- Department of Psychology and Neuroscience Program, University of Guelph, Guelph, ON, Canada.
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18
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Huzian O, Baka J, Csakvari E, Dobos N, Leranth C, Siklos L, Duman RS, Farkas T, Hajszan T. Stress Resilience is Associated with Hippocampal Synaptoprotection in the Female Rat Learned Helplessness Paradigm. Neuroscience 2021; 459:85-103. [PMID: 33524494 DOI: 10.1016/j.neuroscience.2021.01.029] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 01/11/2021] [Accepted: 01/21/2021] [Indexed: 12/28/2022]
Abstract
The synaptogenic hypothesis of major depressive disorder implies that preventing the onset of depressive-like behavior also prevents the loss of hippocampal spine synapses. By applying the psychoactive drugs, diazepam and fluoxetine, we investigated whether blocking the development of helpless behavior by promoting stress resilience in the rat learned helplessness paradigm is associated with a synaptoprotective action in the hippocampus. Adult ovariectomized and intact female Sprague-Dawley rats (n = 297) were treated with either diazepam, fluoxetine, or vehicle, exposed to inescapable footshocks or sham stress, and tested in an active escape task to assess helpless behavior. Escape-evoked corticosterone secretion, as well as remodeling of hippocampal spine synapses at a timepoint representing the onset of escape testing were also analyzed. In ovariectomized females, treatment with diazepam prior to stress exposure prevented helpless behavior, blocked the loss of hippocampal spine synapses, and muted the corticosterone surge evoked by escape testing. Although fluoxetine stimulated escape performance and hippocampal synaptogenesis under non-stressed conditions, almost all responses to fluoxetine were abolished following exposure to inescapable stress. Only a much higher dose of fluoxetine was capable of partly reproducing the strong protective actions of diazepam. Importantly, these protective actions were retained in the presence of ovarian hormones. Our findings indicate that stress resilience is associated with the preservation of spine synapses in the hippocampus, raising the possibility that, besides synaptogenesis, hippocampal synaptoprotection is also implicated in antidepressant therapy.
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Affiliation(s)
- Orsolya Huzian
- Institute of Biophysics, Biological Research Center, Temesvari Krt 62, 6726 Szeged, Hungary
| | - Judith Baka
- Institute of Biophysics, Biological Research Center, Temesvari Krt 62, 6726 Szeged, Hungary
| | - Eszter Csakvari
- Institute of Biophysics, Biological Research Center, Temesvari Krt 62, 6726 Szeged, Hungary
| | - Nikoletta Dobos
- Institute of Biophysics, Biological Research Center, Temesvari Krt 62, 6726 Szeged, Hungary
| | - Csaba Leranth
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, United States; Department of Neuroscience, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, United States
| | - Laszlo Siklos
- Institute of Biophysics, Biological Research Center, Temesvari Krt 62, 6726 Szeged, Hungary
| | - Ronald S Duman
- Department of Psychiatry, Yale University School of Medicine, 34 Park Street, New Haven, CT 06508, United States; Department of Pharmacology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, United States
| | - Tamas Farkas
- Department of Physiology, Anatomy, and Neuroscience, University of Szeged Faculty of Science and Informatics, Kozep Fasor 52, 6726 Szeged, Hungary
| | - Tibor Hajszan
- Institute of Biophysics, Biological Research Center, Temesvari Krt 62, 6726 Szeged, Hungary; Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, United States.
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19
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Tozzi A, Bellingacci L, Pettorossi VE. Rapid Estrogenic and Androgenic Neurosteroids Effects in the Induction of Long-Term Synaptic Changes: Implication for Early Memory Formation. Front Neurosci 2020; 14:572511. [PMID: 33192257 PMCID: PMC7653679 DOI: 10.3389/fnins.2020.572511] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Accepted: 08/21/2020] [Indexed: 11/17/2022] Open
Abstract
Mounting experimental evidence demonstrate that sex neuroactive steroids (neurosteroids) are essential for memory formation. Neurosteroids have a profound impact on the function and structure of neural circuits and their local synthesis is necessary for the induction of both long-term potentiation (LTP) and long-term depression (LTD) of synaptic transmission and for neural spine formation in different areas of the central nervous system (CNS). Several studies demonstrated that in the hippocampus, 17β-estradiol (E2) is necessary for inducing LTP, while 5α-dihydrotestosterone (DHT) is necessary for inducing LTD. This contribution has been proven by administering sex neurosteroids in rodent models and by using blocking agents of their synthesis or of their specific receptors. The general opposite role of sex neurosteroids in synaptic plasticity appears to be dependent on their different local availability in response to low or high frequency of synaptic stimulation, allowing the induction of bidirectional synaptic plasticity. The relevant contribution of these neurosteroids to synaptic plasticity has also been described in other brain regions involved in memory processes such as motor learning, as in the case of the vestibular nuclei, the cerebellum, and the basal ganglia, or as the emotional circuit of the amygdala. The rapid effects of sex neurosteroids on neural synaptic plasticity need the maintenance of a tonic or phasic local steroid synthesis determined by neural activity but might also be influenced by circulating hormones, age, and gender. To disclose the exact mechanisms how sex neurosteroids participate in finely tuning long-term synaptic changes and spine remodeling, further investigation is required.
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Affiliation(s)
- Alessandro Tozzi
- Department of Experimental Medicine, University of Perugia, Perugia, Italy
| | - Laura Bellingacci
- Department of Experimental Medicine, University of Perugia, Perugia, Italy
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20
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Nicholson K, MacLusky NJ, Leranth C. Synaptic effects of estrogen. VITAMINS AND HORMONES 2020; 114:167-210. [PMID: 32723543 DOI: 10.1016/bs.vh.2020.06.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The concept that estradiol may act as a local neuromodulator in the brain, rapidly affecting connectivity and synaptic function, has been firmly established by research over the last 30 years. De novo synthesis of estradiol within the brain as well as signaling mechanisms mediating responses to the hormone have been demonstrated, along with morphological evidence indicating rapid changes in synaptic input following increases in local estradiol levels. These rapid synaptic effects may play important roles in both physiological and pathophysiological responses to changes in circulating hormone levels, as well as in neurodegenerative disease. How local effects of estradiol on synaptic plasticity are integrated into changes in the overall activity of neural networks in the brain, however, remains a subject that is only incompletely understood.
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Affiliation(s)
- Kate Nicholson
- Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada
| | - Neil J MacLusky
- Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada
| | - Csaba Leranth
- Department of Obstetrics, Gynecology and Reproductive Sciences, Yale University, School of Medicine, New Haven, CT, United States.
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21
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Laube C, van den Bos W, Fandakova Y. The relationship between pubertal hormones and brain plasticity: Implications for cognitive training in adolescence. Dev Cogn Neurosci 2020; 42:100753. [PMID: 32072931 PMCID: PMC7005587 DOI: 10.1016/j.dcn.2020.100753] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 12/20/2019] [Accepted: 01/07/2020] [Indexed: 12/12/2022] Open
Abstract
Adolescence may mark a sensitive period for the development of higher-order cognition through enhanced plasticity of cortical circuits. At the same time, animal research indicates that pubertal hormones may represent one key mechanism for closing sensitive periods in the associative neocortex, thereby resulting in decreased plasticity of cortical circuits in adolescence. In the present review, we set out to solve some of the existing ambiguity and examine how hormonal changes associated with pubertal onset may modulate plasticity in higher-order cognition during adolescence. We build on existing age-comparative cognitive training studies to explore how the potential for change in neural resources and behavioral repertoire differs across age groups. We review animal and human brain imaging studies, which demonstrate a link between brain development, neurochemical mechanisms of plasticity, and pubertal hormones. Overall, the existent literature indicates that pubertal hormones play a pivotal role in regulating the mechanisms of experience-dependent plasticity during adolescence. However, the extent to which hormonal changes associated with pubertal onset increase or decrease brain plasticity may depend on the specific cognitive domain, the sex, and associated brain networks. We discuss implications for future research and suggest that systematical longitudinal assessments of pubertal change together with cognitive training interventions may be a fruitful way toward a better understanding of adolescent plasticity. As the age of pubertal onset is decreasing across developed societies, this may also have important educational and clinical implications, especially with respect to the effects that earlier puberty has on learning.
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Affiliation(s)
- Corinna Laube
- Center for Lifespan Psychology, Max Planck Institute for Human Development, Berlin, Germany
| | | | - Yana Fandakova
- Center for Lifespan Psychology, Max Planck Institute for Human Development, Berlin, Germany.
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22
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Salehabadi S, Abrari K, Elahdadi Salmani M, Nasiri M, Lashkarbolouki T. Investigating the role of the amygdala orexin receptor 1 in memory acquisition and extinction in a rat model of PTSD. Behav Brain Res 2020; 384:112455. [DOI: 10.1016/j.bbr.2019.112455] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 12/17/2019] [Accepted: 12/26/2019] [Indexed: 11/15/2022]
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23
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Gogos A, Sbisa A, Witkamp D, van den Buuse M. Sex differences in the effect of maternal immune activation on cognitive and psychosis-like behaviour in Long Evans rats. Eur J Neurosci 2020; 52:2614-2626. [PMID: 31901174 DOI: 10.1111/ejn.14671] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2019] [Revised: 12/16/2019] [Accepted: 12/23/2019] [Indexed: 02/06/2023]
Abstract
Maternal immune activation during pregnancy is associated with increased risk of development of schizophrenia in later life. There are sex differences in schizophrenia, particularly in terms of age of onset, course of illness and severity of symptoms. However, there is limited and inconsistent literature on sex differences in the effects of maternal immune activation on behaviour with relevance to schizophrenia. The aim of this study was therefore to investigate sex differences in the effects of maternal immune activation by treating Long Evans rats with poly(I:C) on gestational day 15. We compared adult male and female offspring on spatial working memory in the touchscreen trial-unique nonmatching-to-location task, pairwise discrimination and reversal learning, as well as on prepulse inhibition and psychotropic drug-induced locomotor hyperactivity. Male, but not female poly(I:C) offspring displayed a deficit in spatial working memory, particularly at the longer delay. Neither pairwise discrimination nor reversal learning showed an effect of poly(I:C), but female controls outperformed male controls in the reversal learning task. Significant reduction of prepulse inhibition and enhancement of acute methamphetamine-induced locomotor hyperactivity was found similarly in male and female poly(I:C) offspring. These results show that maternal immune activation induces a range of behavioural effects in the offspring, with sex specificity in the effects of maternal immune activation on some aspects of cognition, but not psychosis-like behaviour.
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Affiliation(s)
- Andrea Gogos
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Vic., Australia
| | - Alyssa Sbisa
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Vic., Australia.,School of Psychology and Public Health, La Trobe University, Melbourne, Vic., Australia
| | - Diede Witkamp
- School of Psychology and Public Health, La Trobe University, Melbourne, Vic., Australia
| | - Maarten van den Buuse
- School of Psychology and Public Health, La Trobe University, Melbourne, Vic., Australia.,Department of Pharmacology, University of Melbourne, Melbourne, Vic., Australia.,The College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, QLD, Australia
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24
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Llorente R, Marraudino M, Carrillo B, Bonaldo B, Simon-Areces J, Abellanas-Pérez P, Rivero-Aguilar M, Fernandez-Garcia JM, Pinos H, Garcia-Segura LM, Collado P, Grassi D. G Protein-Coupled Estrogen Receptor Immunoreactivity Fluctuates During the Estrous Cycle and Show Sex Differences in the Amygdala and Dorsal Hippocampus. Front Endocrinol (Lausanne) 2020; 11:537. [PMID: 32849310 PMCID: PMC7426398 DOI: 10.3389/fendo.2020.00537] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 07/02/2020] [Indexed: 12/15/2022] Open
Abstract
G protein-coupled estrogen receptor (GPER) in the amygdala and the dorsal hippocampus mediates actions of estradiol on anxiety, social recognition and spatial memory. In addition, GPER participates in the estrogenic regulation of synaptic function in the amygdala and in the process of adult neurogenesis in the dentate gyrus. While the distribution of the canonical estrogen receptors α and β in the amygdala and dorsal hippocampus are well characterized, little is known about the regional distribution of GPER in these brain regions and whether this distribution is affected by sex or the stages of the estrous cycle. In this study we performed a morphometric analysis of GPER immunoreactivity in the posterodorsal medial, anteroventral medial, basolateral, basomedial and central subdivisions of the amygdala and in all the histological layers of CA1 and the dentate gyrus of the dorsal hippocampal formation. The number of GPER immunoreactive cells was estimated in these different structures. GPER immunoreactivity was detected in all the assessed subdivisions of the amygdaloid nucleus and dorsal hippocampal formation. The number of GPER immunoreactive cells was higher in males than in estrus females in the central (P = 0.001) and the posterodorsal medial amygdala (P < 0.05); higher in males than in diestrus females in the strata orients (P < 0.01) and radiatum-lacunosum-moleculare (P < 0.05) of CA1-CA3 and in the molecular layer of the dentate gyrus (P < 0.01); higher in diestrus females than in males in the basolateral amygdala (P < 0.05); higher in diestrus females than in estrus females in the central (P < 0.01), posterodorsal medial (P < 0.01) and basolateral amygdala (P < 0.01) and higher in estrus females than in diestrus females in the strata oriens (P < 0.05) and radiatum-lacunosum-moleculare (P < 0.05) of CA1-CA3 and in the molecular layer (P < 0.05) and the hilus of the dentate gyrus (P < 0.05). The findings suggest that estrogenic regulation of the amygdala and hippocampus through GPER may be different in males and in females and may fluctuate during the estrous cycle.
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Affiliation(s)
- Ricardo Llorente
- Department of Preclinical Odontology, Universidad Europea de Madrid, Madrid, Spain
| | - Marilena Marraudino
- Department of Neuroscience Rita Levi Montalcini, Neuroscience Institute Cavalieri Ottolenghi, University of Turin, Turin, Italy
| | - Beatriz Carrillo
- Department of Psychobiology, Universidad Nacional de Educación a Distancia (UNED), Madrid, Spain
- Instituto Mixto de Investigación Escuela Nacional de Sanidad-UNED (IMIENS), Madrid, Spain
| | - Brigitta Bonaldo
- Department of Neuroscience Rita Levi Montalcini, Neuroscience Institute Cavalieri Ottolenghi, University of Turin, Turin, Italy
| | - Julia Simon-Areces
- Department of Physiotherapy, Podology and Dance, Universidad Europea de Madrid, Madrid, Spain
| | | | | | - Jose M. Fernandez-Garcia
- Department of Psychobiology, Universidad Nacional de Educación a Distancia (UNED), Madrid, Spain
- Instituto Mixto de Investigación Escuela Nacional de Sanidad-UNED (IMIENS), Madrid, Spain
| | - Helena Pinos
- Department of Psychobiology, Universidad Nacional de Educación a Distancia (UNED), Madrid, Spain
- Instituto Mixto de Investigación Escuela Nacional de Sanidad-UNED (IMIENS), Madrid, Spain
| | - Luis M. Garcia-Segura
- Cajal Institute, CSIC, Madrid, Spain
- Centro de Investigación Biomédica en Red Fragilidad y Envejecimiento Saludable (CIBERFES), Instituto de Salud Carlos III, Madrid, Spain
| | - Paloma Collado
- Department of Psychobiology, Universidad Nacional de Educación a Distancia (UNED), Madrid, Spain
- Instituto Mixto de Investigación Escuela Nacional de Sanidad-UNED (IMIENS), Madrid, Spain
| | - Daniela Grassi
- Department of Preclinical Odontology, Universidad Europea de Madrid, Madrid, Spain
- Department of Psychobiology, Universidad Nacional de Educación a Distancia (UNED), Madrid, Spain
- Instituto Mixto de Investigación Escuela Nacional de Sanidad-UNED (IMIENS), Madrid, Spain
- Cajal Institute, CSIC, Madrid, Spain
- Centro de Investigación Biomédica en Red Fragilidad y Envejecimiento Saludable (CIBERFES), Instituto de Salud Carlos III, Madrid, Spain
- *Correspondence: Daniela Grassi ;
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17α Estradiol promotes plasticity of spared inputs in the adult amblyopic visual cortex. Sci Rep 2019; 9:19040. [PMID: 31836739 PMCID: PMC6910995 DOI: 10.1038/s41598-019-55158-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 11/20/2019] [Indexed: 01/10/2023] Open
Abstract
The promotion of structural and functional plasticity by estrogens is a promising approach to enhance central nervous system function in the aged. However, how the sensitivity to estrogens is regulated across brain regions, age and experience is poorly understood. To ask if estradiol treatment impacts structural and functional plasticity in sensory cortices, we examined the acute effect of 17α-Estradiol in adult Long Evans rats following chronic monocular deprivation, a manipulation that reduces the strength and selectivity of deprived eye vision. Chronic monocular deprivation decreased thalamic input from the deprived eye to the binocular visual cortex and accelerated short-term depression of the deprived eye pathway, but did not change the density of excitatory synapses in primary visual cortex. Importantly, we found that the classical estrogen receptors ERα and ERβ were robustly expressed in the adult visual cortex, and that a single dose of 17α-Estradiol reduced the expression of the calcium-binding protein parvalbumin, decreased the integrity of the extracellular matrix and increased the size of excitatory postsynaptic densities. Furthermore, 17α-Estradiol enhanced experience-dependent plasticity in the amblyopic visual cortex, by promoting response potentiation of the pathway served by the non-deprived eye. The promotion of plasticity at synapses serving the non-deprived eye may reflect selectivity for synapses with an initially low probability of neurotransmitter release, and may inform strategies to remap spared inputs around a scotoma or a cortical infarct.
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Dorsal Hippocampal Actin Polymerization Is Necessary for Activation of G-Protein-Coupled Estrogen Receptor (GPER) to Increase CA1 Dendritic Spine Density and Enhance Memory Consolidation. J Neurosci 2019; 39:9598-9610. [PMID: 31628182 DOI: 10.1523/jneurosci.2687-18.2019] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 09/03/2019] [Accepted: 10/13/2019] [Indexed: 11/21/2022] Open
Abstract
Activation of the membrane estrogen receptor G-protein-coupled estrogen receptor (GPER) in ovariectomized mice via the GPER agonist G-1 mimics the beneficial effects of 17β-estradiol (E2) on hippocampal CA1 spine density and memory consolidation, yet the cell-signaling mechanisms mediating these effects remain unclear. The present study examined the role of actin polymerization and c-Jun N-terminal kinase (JNK) phosphorylation in mediating effects of dorsal hippocampally infused G-1 on CA1 dendritic spine density and consolidation of object recognition and spatial memories in ovariectomized mice. We first showed that object learning increased apical CA1 spine density in the dorsal hippocampus (DH) within 40 min. We then found that DH infusion of G-1 increased both CA1 spine density and phosphorylation of the actin polymerization regulator cofilin, suggesting that activation of GPER may increase spine morphogenesis through actin polymerization. As with memory consolidation in our previous work (Kim et al., 2016), effects of G-1 on CA1 spine density and cofilin phosphorylation depended on JNK phosphorylation in the DH. Also consistent with our previous findings, E2-induced cofilin phosphorylation was not dependent on GPER activation. Finally, we found that infusion of the actin polymerization inhibitor, latrunculin A, into the DH prevented G-1 from increasing apical CA1 spine density and enhancing both object recognition and spatial memory consolidation. Collectively, these data demonstrate that GPER-mediated hippocampal spinogenesis and memory consolidation depend on JNK and cofilin signaling, supporting a critical role for actin polymerization in the GPER-induced regulation of hippocampal function in female mice.SIGNIFICANCE STATEMENT Emerging evidence suggests that G-protein-coupled estrogen receptor (GPER) activation mimics effects of 17β-estradiol on hippocampal memory consolidation. Unlike canonical estrogen receptors, GPER activation is associated with reduced cancer cell proliferation; thus, understanding the molecular mechanisms through which GPER regulates hippocampal function may provide new avenues for the development of drugs that provide the cognitive benefits of estrogens without harmful side effects. Here, we demonstrate that GPER increases CA1 dendritic spine density and hippocampal memory consolidation in a manner dependent on actin polymerization and c-Jun N-terminal kinase phosphorylation. These findings provide novel insights into the role of GPER in mediating hippocampal morphology and memory consolidation, and may suggest first steps toward new therapeutics that more safely and effectively reduce memory decline in menopausal women.
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Hillerer KM, Slattery DA, Pletzer B. Neurobiological mechanisms underlying sex-related differences in stress-related disorders: Effects of neuroactive steroids on the hippocampus. Front Neuroendocrinol 2019; 55:100796. [PMID: 31580837 PMCID: PMC7115954 DOI: 10.1016/j.yfrne.2019.100796] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 09/26/2019] [Accepted: 09/27/2019] [Indexed: 12/19/2022]
Abstract
Men and women differ in their vulnerability to a variety of stress-related illnesses, but the underlying neurobiological mechanisms are not well understood. This is likely due to a comparative dearth of neurobiological studies that assess male and female rodents at the same time, while human neuroimaging studies often don't model sex as a variable of interest. These sex differences are often attributed to the actions of sex hormones, i.e. estrogens, progestogens and androgens. In this review, we summarize the results on sex hormone actions in the hippocampus and seek to bridge the gap between animal models and findings in humans. However, while effects of sex hormones on the hippocampus are largely consistent in animals and humans, methodological differences challenge the comparability of animal and human studies on stress effects. We summarise our current understanding of the neurobiological mechanisms that underlie sex-related differences in behavior and discuss implications for stress-related illnesses.
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Affiliation(s)
- Katharina M Hillerer
- Department of Obstetrics and Gynaecology, Salzburger Landeskrankenhaus (SALK), Paracelsus Medical University (PMU), Clinical Research Center Salzburg (CRCS), Salzburg, Austria.
| | - David A Slattery
- Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, University Hospital, Goethe University, Frankfurt, Germany
| | - Belinda Pletzer
- Department of Psychology, University of Salzburg, Salzburg, Austria; Centre for Cognitive Neuroscience, University of Salzburg, Salzburg, Austria
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Concurrent Medial Prefrontal Cortex and Dorsal Hippocampal Activity Is Required for Estradiol-Mediated Effects on Object Memory and Spatial Memory Consolidation. eNeuro 2019; 6:6/4/ENEURO.0271-19.2019. [PMID: 31431561 PMCID: PMC6709231 DOI: 10.1523/eneuro.0271-19.2019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 07/12/2019] [Indexed: 11/23/2022] Open
Abstract
Highlighted Research Paper:Chemogenetic Suppression of Medial Prefrontal-Dorsal Hippocampal Interactions Prevents Estrogenic Enhancement of Memory Consolidation in Female Mice by, Jennifer J. Tuscher, Lisa R. Taxier, Jayson C. Schalk, Jacqueline M. Haertel, and Karyn M. Frick.
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Treccani G, Ardalan M, Chen F, Musazzi L, Popoli M, Wegener G, Nyengaard JR, Müller HK. S-Ketamine Reverses Hippocampal Dendritic Spine Deficits in Flinders Sensitive Line Rats Within 1 h of Administration. Mol Neurobiol 2019; 56:7368-7379. [PMID: 31037646 DOI: 10.1007/s12035-019-1613-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Accepted: 04/15/2019] [Indexed: 11/26/2022]
Abstract
When administered as a single subanesthetic dose, the N-methyl-D-aspartate (NMDA) receptor antagonist, ketamine, produces rapid (within hours) and relatively sustained antidepressant actions even in treatment-resistant patients. Preclinical studies have shown that ketamine increases dendritic spine density and synaptic proteins in brain areas critical for the actions of antidepressants, yet the temporal relationship between structural changes and the onset of antidepressant action remains poorly understood. In this study, we examined the effects of a single dose of S-ketamine (15 mg/kg) on dendritic length, dendritic arborization, spine density, and spine morphology in the Flinders Sensitive and Flinders Resistant Line (FSL/FRL) rat model of depression. We found that already 1 h after injection with ketamine, apical dendritic spine deficits in CA1 pyramidal neurons of FSL rats were completely restored. Notably, the observed increase in spine density was attributable to regulation of both mushroom and long-thin spines. In contrast, ketamine had no effect on dendritic spine density in FRL rats. On the molecular level, ketamine normalized elevated levels of phospho-cofilin and the NMDA receptor subunits GluN2A and GluN2B and reversed homer3 deficiency in hippocampal synaptosomes of FSL rats. Taken together, our data suggest that rapid formation of new spines may provide an important structural substrate during the initial phase of ketamine's antidepressant action.
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Affiliation(s)
- Giulia Treccani
- Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, Skovagervej 72, 8240, Risskov, Denmark
- Department of Psychiatry and Psychotherapy, Johannes Gutenberg University Medical Center Mainz, Untere Zahlbacher Straße 8, Mainz, Germany
- Deutsches Resilienz Zentrum (DRZ) gGmbH, Mainz, Germany
| | - Maryam Ardalan
- Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, Skovagervej 72, 8240, Risskov, Denmark
| | - Fenghua Chen
- Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, Skovagervej 72, 8240, Risskov, Denmark
| | - Laura Musazzi
- Laboratory of Neuropsychopharmacology and Functional Neurogenomics - Dipartimento di Scienze Farmacologiche e Biomolecolari and Center of Excellence on Neurodegenerative Diseases, University of Milano, Milan, Italy
| | - Maurizio Popoli
- Laboratory of Neuropsychopharmacology and Functional Neurogenomics - Dipartimento di Scienze Farmacologiche e Biomolecolari and Center of Excellence on Neurodegenerative Diseases, University of Milano, Milan, Italy
| | - Gregers Wegener
- Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, Skovagervej 72, 8240, Risskov, Denmark
- AUGUST Centre, Department of Clinical Medicine, Aarhus University, Risskov, Denmark
| | - Jens Randel Nyengaard
- Core Center for Molecular Morphology, Section for Stereology and Microscopy, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
- Centre for Stochastic Geometry and Advanced Bioimaging, Aarhus University, Aarhus, Denmark
| | - Heidi Kaastrup Müller
- Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, Skovagervej 72, 8240, Risskov, Denmark.
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Estrogen-Dependent Functional Spine Dynamics in Neocortical Pyramidal Neurons of the Mouse. J Neurosci 2019; 39:4874-4888. [PMID: 30992373 DOI: 10.1523/jneurosci.2772-18.2019] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Revised: 04/09/2019] [Accepted: 04/11/2019] [Indexed: 11/21/2022] Open
Abstract
Surgical ovariectomy has been shown to reduce spine density in hippocampal CA1 pyramidal cells of rodents, and this reduction is reversed by 17β-estradiol (E2) treatment in a model of human estrogen replacement therapy. Here, we report reduction of spine density in apical dendrites of layer 5 pyramidal neurons of several neocortical regions that is reversed by subsequent E2 treatment in ovariectomized (OVX) female Thy1M-EGFP mice. We also found that OVX-associated reduction of spine density in somatosensory cortex was accompanied by a reduction in miniature EPSC (mEPSC) frequency (but not mIPSC frequency), indicating a change in functional synapses. OVX-associated spine loss in somatosensory cortex was also rescued by an agonist of the G-protein-linked estrogen receptor (GPER) but not by agonists of the classic estrogen receptors ERα/ERβ, whereas the opposite selectivity was found in area CA1. Acute treatment of neocortical slices with E2 also rescued the OVX-associated reduction in mEPSC frequency, which could be mimicked by a GPER agonist and abolished by a GPER antagonist. Time-lapse in vivo two-photon imaging showed that OVX-associated reduction in spine density is achieved by both an increase in spine loss rate and a decrease in spine gain rate and that subsequent rescue by E2 reversed both of these processes. Crucially, the spines added after E2 rescue were no more likely to reappear at or nearby the sites of pre-OVX spines than those in control mice treated with vehicle. Thus, a model of estrogen replacement therapy, although restoring spine density and dynamics, does not entirely restore functional connectivity.SIGNIFICANCE STATEMENT Estrogen replacement therapy following menopause or surgical removal of the ovaries is a widespread medical practice, yet little is known about the consequences of such treatment for cells in the brain. Here, we show that estrogen replacement reverses some of the effects of surgical removal of the ovaries on the structure and function of brain cells in the mouse. Yet, importantly, the fine wiring of the brain is not returned to the presurgery state by estrogen treatment, suggesting lasting functional consequences.
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31
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Sheppard PAS, Choleris E, Galea LAM. Structural plasticity of the hippocampus in response to estrogens in female rodents. Mol Brain 2019; 12:22. [PMID: 30885239 PMCID: PMC6423800 DOI: 10.1186/s13041-019-0442-7] [Citation(s) in RCA: 105] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 03/11/2019] [Indexed: 01/05/2023] Open
Abstract
It is well established that estrogens affect neuroplasticity in a number of brain regions. In particular, estrogens modulate and mediate spine and synapse formation as well as neurogenesis in the hippocampal formation. In this review, we discuss current research exploring the effects of estrogens on dendritic spine plasticity and neurogenesis with a focus on the modulating factors of sex, age, and pregnancy. Hormone levels, including those of estrogens, fluctuate widely across the lifespan from early life to puberty, through adulthood and into old age, as well as with pregnancy and parturition. Dendritic spine formation and modulation are altered both by rapid (likely non-genomic) and classical (genomic) actions of estrogens and have been suggested to play a role in the effects of estrogens on learning and memory. Neurogenesis in the hippocampus is influenced by age, the estrous cycle, pregnancy, and parity in female rodents. Furthermore, sex differences exist in hippocampal cellular and molecular responses to estrogens and are briefly discussed throughout. Understanding how structural plasticity in the hippocampus is affected by estrogens and how these effects can influence function and be influenced by other factors, such as experience and sex, is critical and can inform future treatments in conditions involving the hippocampus.
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Affiliation(s)
- Paul A. S. Sheppard
- Department of Psychology, Graduate Program in Neuroscience, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC V6T 1Z3 Canada
| | - Elena Choleris
- Department of Psychology & Neuroscience Program, University of Guelph, Guelph, ON N1G 2W1 Canada
| | - Liisa A. M. Galea
- Department of Psychology, Graduate Program in Neuroscience, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC V6T 1Z3 Canada
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32
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Prokai-Tatrai K, Nguyen V, Prokai L. 10β,17α-Dihydroxyestra-1,4-dien-3-one: A Bioprecursor Prodrug Preferentially Producing 17α-Estradiol in the Brain for Targeted Neurotherapy. ACS Chem Neurosci 2018; 9:2528-2533. [PMID: 29843514 PMCID: PMC6582959 DOI: 10.1021/acschemneuro.8b00184] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Uterotrophic effect of 17α-estradiol, the C17 epimer of the main human estrogen 17β-estradiol, was shown to manifest in animal models at doses lower than those necessary for central outcome raising concerns about its potential to treat maladies of the central nervous system. We introduce here 10β,17α-dihydroxyestra-1,4-dien-3-one (α-DHED) that acts as a bioprecursor prodrug producing 17α-estradiol with remarkable selectivity to the brain and, therefore, without appreciable exposure of the periphery to the parent steroid. This distinguishing feature of α-DHED is shown by using an estrogen-responsive mouse model with complementary LC-MS/MS measurement of drug contents in target tissues. Our data warrant further research to fully establish the potential of α-DHED for a safe and efficacious 17α-estradiol-based neurotherapy.
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Affiliation(s)
| | - Vien Nguyen
- Department of Pharmacology and Neuroscience, and the Institute for Healthy Aging, University of North Texas Health Science Center, 3500 Camp Bowie Boulevard, Fort Worth, TX 76107-2699, USA
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33
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Waters EM, Mazid S, Dodos M, Puri R, Janssen WG, Morrison JH, McEwen BS, Milner TA. Effects of estrogen and aging on synaptic morphology and distribution of phosphorylated Tyr1472 NR2B in the female rat hippocampus. Neurobiol Aging 2018; 73:200-210. [PMID: 30384123 DOI: 10.1016/j.neurobiolaging.2018.09.025] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 08/10/2018] [Accepted: 09/18/2018] [Indexed: 12/12/2022]
Abstract
Age and estrogens may impact the mobility of N-methyl-D-aspartate receptors (NMDARs) in hippocampal synapses. Here, we used serial section immunogold electron microscopy to examine whether phosphorylated tyrosine 1472 NR2B (pY1472), which is involved in the surface expression of NMDARs, is altered in the dorsal hippocampus of young (3-4 months old) and aged (∼24 months old) ovariectomized rats treated with 17β-estradiol or vehicle for 2 days. The number of gold particles labeling pY1472 was higher in presynaptic and postsynaptic compartments of aged rats with low estradiol (vehicle-treated) compared to other groups. In terminals, pY1472 levels were elevated in aged rats but reduced by estradiol treatment to levels seen in young rats. Conversely, the mitochondria number was lower in aged females but was restored to young levels by estradiol. In the postsynaptic density and dendritic spines, estradiol reduced pY1472 in young and aged rats. As phosphorylation at Y1472 blocks NR2B endocytosis, reduction of pY1472 by estradiol suggests another mechanism through which estrogen enhances synaptic plasticity by altering localization of NMDAR subunits within synapses.
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Affiliation(s)
- Elizabeth M Waters
- Laboratory of Neuroendocrinology, The Rockefeller University, New York, NY, USA
| | - Sanoara Mazid
- Laboratory of Neuroendocrinology, The Rockefeller University, New York, NY, USA
| | - Mariana Dodos
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
| | - Rishi Puri
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - William G Janssen
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - John H Morrison
- Department of Neurology, Center for Neuroscience, The California National Primate Research Center, UC Davis, Davis, CA, USA
| | - Bruce S McEwen
- Laboratory of Neuroendocrinology, The Rockefeller University, New York, NY, USA
| | - Teresa A Milner
- Laboratory of Neuroendocrinology, The Rockefeller University, New York, NY, USA; Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA.
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34
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Paletta P, Sheppard PAS, Matta R, Ervin KSJ, Choleris E. Rapid effects of estrogens on short-term memory: Possible mechanisms. Horm Behav 2018; 104:88-99. [PMID: 29847771 DOI: 10.1016/j.yhbeh.2018.05.019] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 05/24/2018] [Accepted: 05/26/2018] [Indexed: 01/11/2023]
Abstract
Contribution to Special Issue on Fast effects of steroids. Estrogens affect learning and memory through rapid and delayed mechanisms. Here we review studies on rapid effects on short-term memory. Estradiol rapidly improves social and object recognition memory, spatial memory, and social learning when administered systemically. The dorsal hippocampus mediates estrogen rapid facilitation of object, social and spatial short-term memory. The medial amygdala mediates rapid facilitation of social recognition. The three estrogen receptors, α (ERα), β (ERβ) and the G-protein coupled estrogen receptor (GPER) appear to play different roles depending on the task and brain region. Both ERα and GPER agonists rapidly facilitate short-term social and object recognition and spatial memory when administered systemically or into the dorsal hippocampus and facilitate social recognition in the medial amygdala. Conversely, only GPER can facilitate social learning after systemic treatment and an ERβ agonist only rapidly improved short-term spatial memory when given systemically or into the hippocampus, but also facilitates social recognition in the medial amygdala. Investigations into the mechanisms behind estrogens' rapid effects on short term memory showed an involvement of the extracellular signal-regulated kinase (ERK) and the phosphoinositide 3-kinase (PI3K) kinase pathways. Recent evidence also showed that estrogens interact with the neuropeptide oxytocin in rapidly facilitating social recognition. Estrogens can increase the production and/or release of oxytocin and other neurotransmitters, such as dopamine and acetylcholine. Therefore, it is possible that estrogens' rapid effects on short-term memory may occur through the regulation of various neurotransmitters, although more research is need on these interactions as well as the mechanisms of estrogens' actions on short-term memory.
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Affiliation(s)
- Pietro Paletta
- Department of Psychology and Neuroscience Program, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - Paul A S Sheppard
- Department of Psychology and Neuroscience Program, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - Richard Matta
- Department of Psychology and Neuroscience Program, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - Kelsy S J Ervin
- Department of Psychology and Neuroscience Program, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - Elena Choleris
- Department of Psychology and Neuroscience Program, University of Guelph, Guelph, ON N1G 2W1, Canada.
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Luine V, Serrano P, Frankfurt M. Rapid effects on memory consolidation and spine morphology by estradiol in female and male rodents. Horm Behav 2018; 104:111-118. [PMID: 29669258 PMCID: PMC6274598 DOI: 10.1016/j.yhbeh.2018.04.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Revised: 04/09/2018] [Accepted: 04/13/2018] [Indexed: 12/25/2022]
Abstract
Contribution to Special Issue on Fast effects of steroids. Rapid, neurosteroid-like effects of estrogens on memory consolidation during recognition memory tasks in both male and female rodents are described. We discuss how these mnemonic changes are related to rapid estrogenic effects on dendritic spine density, the distribution of spine types and the expression of PSD95 and GluA2 within spines in the hippocampus and medial prefrontal cortex, two areas critical for learning and memory. Overall, these data lead to the conclusion that estrogens are capable of exerting rapid and potent influences on memory and spine morphology in both sexes. The demonstration of estrogenic effects in males, which are used in the majority of memory studies, may provide a model for better understanding how hormone dependent changes in signaling pathways mediating memory and spinogenesis are coordinated to promote memory consolidation.
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Affiliation(s)
- Victoria Luine
- Department of Psychology, Hunter College of CUNY, New York, NY, USA.
| | - Peter Serrano
- Department of Psychology, Hunter College of CUNY, New York, NY, USA
| | - Maya Frankfurt
- Department of Science Education, Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Hempstead, NY, USA
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Vahaba DM, Remage-Healey L. Neuroestrogens rapidly shape auditory circuits to support communication learning and perception: Evidence from songbirds. Horm Behav 2018; 104:77-87. [PMID: 29555375 PMCID: PMC7025793 DOI: 10.1016/j.yhbeh.2018.03.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 03/15/2018] [Accepted: 03/15/2018] [Indexed: 12/19/2022]
Abstract
Contribution to Special Issue on Fast effects of steroids. Steroid hormones, such as estrogens, were once thought to be exclusively synthesized in the ovaries and enact transcriptional changes over the course of hours to days. However, estrogens are also locally synthesized within neural circuits, wherein they rapidly (within minutes) modulate a range of behaviors, including spatial cognition and communication. Here, we review the role of brain-derived estrogens (neuroestrogens) as modulators within sensory circuits in songbirds. We first present songbirds as an attractive model to explore how neuroestrogens in auditory cortex modulate vocal communication processing and learning. Further, we examine how estrogens may enhance vocal learning and auditory memory consolidation in sensory cortex via mechanisms similar to those found in the hippocampus of rodents and birds. Finally, we propose future directions for investigation, including: 1) the extent of developmental and hemispheric shifts in aromatase and membrane estrogen receptor expression in auditory circuits; 2) how neuroestrogens may impact inhibitory interneurons to regulate audition and critical period plasticity; and, 3) dendritic spine plasticity as a candidate mechanism mediating estrogen-dependent effects on vocal learning. Together, this perspective of estrogens as neuromodulators in the vertebrate brain has opened new avenues in understanding sensory plasticity, including how hormones can act on communication circuits to influence behaviors in other vocal learning species, such as in language acquisition and speech processing in humans.
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Affiliation(s)
- Daniel M Vahaba
- Neuroscience and Behavior Program, Center for Neuroendocrine Studies, University of Massachusetts Amherst, Amherst, MA 01003, United States
| | - Luke Remage-Healey
- Neuroscience and Behavior Program, Center for Neuroendocrine Studies, University of Massachusetts Amherst, Amherst, MA 01003, United States.
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37
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Hyer MM, Phillips LL, Neigh GN. Sex Differences in Synaptic Plasticity: Hormones and Beyond. Front Mol Neurosci 2018; 11:266. [PMID: 30108482 PMCID: PMC6079238 DOI: 10.3389/fnmol.2018.00266] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Accepted: 07/13/2018] [Indexed: 12/24/2022] Open
Abstract
Notable sex-differences exist between neural structures that regulate sexually dimorphic behaviors such as reproduction and parenting. While anatomical differences have been well-characterized, advancements in neuroimaging and pharmacology techniques have allowed researchers to identify differences between males and females down to the level of the synapse. Disparate mechanisms at the synaptic level contribute to sex-specific neuroplasticity that is reflected in sex-dependent behaviors. Many of these synaptic differences are driven by the endocrine system and its impact on molecular signaling and physiology. While sex-dependent modifications exist at baseline, further differences emerge in response to stimuli such as stressors. While some of these mechanisms are unifying between sexes, they often have directly opposing consequences in males and females. This variability is tied to gonadal steroids and their interactions with intra- and extra-cellular signaling mechanisms. This review article focuses on the various mechanisms by which sex can alter synaptic plasticity, both directly and indirectly, through steroid hormones such as estrogen and testosterone. That sex can drive neuroplasticity throughout the brain, highlights the importance of understanding sex-dependent neural mechanisms of the changing brain to enhance interpretation of results regarding males and females. As mood and stress responsivity are characterized by significant sex-differences, understanding the molecular mechanisms that may be altering structure and function can improve our understanding of these behavioral and mental characteristics.
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Affiliation(s)
- Molly M Hyer
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, VA, United States
| | - Linda L Phillips
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, VA, United States
| | - Gretchen N Neigh
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, VA, United States
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Soma M, Kim J, Kato A, Kawato S. Src Kinase Dependent Rapid Non-genomic Modulation of Hippocampal Spinogenesis Induced by Androgen and Estrogen. Front Neurosci 2018; 12:282. [PMID: 29765299 PMCID: PMC5938344 DOI: 10.3389/fnins.2018.00282] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Accepted: 04/10/2018] [Indexed: 11/13/2022] Open
Abstract
Dendritic spine is a small membranous protrusion from a neuron's dendrite that typically receives input from an axon terminal at the synapse. Memories are stored in synapses which consist of spines and presynapses. Rapid modulations of dendritic spines induced by hippocampal sex steroids, including dihydrotestosterone (DHT), testosterone (T), and estradiol (E2), are essential for synaptic plasticity. Molecular mechanisms underlying the rapid non-genomic modulation through synaptic receptors of androgen (AR) and estrogen (ER) as well as its downstream kinase signaling, however, have not been well understood. We investigated the possible involvement of Src tyrosine kinase in rapid changes of dendritic spines in response to androgen and estrogen, including DHT, T, and E2, using hippocampal slices from adult male rats. We found that the treatments with DHT (10 nM), T (10 nM), and E2 (1 nM) increased the total density of spines by ~1.22 to 1.26-fold within 2 h using super resolution confocal imaging of Lucifer Yellow-injected CA1 pyramidal neurons. We examined also morphological changes of spines in order to clarify differences between three sex steroids. From spine head diameter analysis, DHT increased middle- and large-head spines, whereas T increased small- and middle-head spines, and E2 increased small-head spines. Upon application of Src tyrosine kinase inhibitor, the spine increases induced through DHT, T, and E2 treatments were completely blocked. These results imply that Src kinase is essentially involved in sex steroid-induced non-genomic modulation of the spine density and morphology. These results also suggest that rapid effects of exogenously applied androgen and estrogen can occur in steroid-depleted conditions, including “acute” hippocampal slices and the hippocampus of gonadectomized animals.
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Affiliation(s)
- Mika Soma
- Department of Cognitive Neuroscience, Faculty of Pharma-Science, Teikyo University, Itabashi, Japan
| | - Jonghyuk Kim
- Department of Cognitive Neuroscience, Faculty of Pharma-Science, Teikyo University, Itabashi, Japan
| | - Asami Kato
- Department of Cognitive Neuroscience, Faculty of Pharma-Science, Teikyo University, Itabashi, Japan
| | - Suguru Kawato
- Department of Cognitive Neuroscience, Faculty of Pharma-Science, Teikyo University, Itabashi, Japan.,Department of Urology, Graduate School of Medicine, Juntendo University, Hongo, Japan.,Department of Biophysics and Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Meguro, Japan
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Korol DL, Wang W. Using a memory systems lens to view the effects of estrogens on cognition: Implications for human health. Physiol Behav 2018; 187:67-78. [PMID: 29203121 PMCID: PMC5844822 DOI: 10.1016/j.physbeh.2017.11.022] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 11/17/2017] [Accepted: 11/20/2017] [Indexed: 01/23/2023]
Abstract
Understanding the organizing and activating effects of gonadal steroids on adult physiology can guide insight into sex differences in and hormonal influences on health and disease, ranging from diabetes and other metabolic disorders, emotion and stress regulation, substance abuse, pain perception, immune function and inflammation, to cognitive function and dysfunction accompanying neurological disorders. Because the brain is highly sensitive to many forms of estrogens, it is not surprising that many adult behaviors, including cognitive function, are modulated by estrogens. Estrogens are known for their facilitating effects on learning and memory, but it is becoming increasingly clear that they also can impair learning and memory of some classes of tasks and may do so through direct actions on specific neural systems. This review takes a multiple memory systems approach to understanding how estrogens can at the same time enhance hippocampus-sensitive place learning and impair striatum-sensitive response learning by exploring the role estrogen receptor signaling may play in the opposing cognitive effects of estrogens. Accumulating evidence suggests that neither receptor subtype nor the timing of treatment, i.e. rapid vs slow, explain the bidirectional effects of estrogens on different types of learning. New findings pointing to neural metabolism and the provision of energy substrates by astrocytes as a candidate mechanism for cognitive enhancement and impairment are discussed.
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Affiliation(s)
- Donna L Korol
- Department of Biology, Syracuse University, Syracuse, NY 13244, United States.
| | - Wei Wang
- Department of Biology, Syracuse University, Syracuse, NY 13244, United States
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40
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Frick KM, Tuscher JJ, Koss WA, Kim J, Taxier LR. Estrogenic regulation of memory consolidation: A look beyond the hippocampus, ovaries, and females. Physiol Behav 2018; 187:57-66. [PMID: 28755863 PMCID: PMC5787049 DOI: 10.1016/j.physbeh.2017.07.028] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 07/14/2017] [Accepted: 07/25/2017] [Indexed: 12/25/2022]
Abstract
The potent estrogen 17β-estradiol (E2) has long been known to regulate the hippocampus and hippocampal-dependent memories in females, and research from the past decade has begun to shed light on the molecular mechanisms through which E2 mediates memory formation in females. Although E2 can also regulate hippocampal function in males, relatively little is known about how E2 influences memory formation in males, or whether sex differences in underlying mechanisms exist. This review, based on a talk given in April 2017 at the American University symposium entitled, "Sex Differences: From Neuroscience to the Clinic and Beyond", first provides an overview of the molecular mechanisms in the dorsal hippocampus through which E2 enhances memory consolidation in ovariectomized female mice. Next, newer research is described demonstrating key roles for the prefrontal cortex and de novo hippocampal E2 synthesis to the memory-enhancing effects of E2 in females. The review then discusses the effects of de novo and exogenous E2 on hippocampal memory consolidation in both sexes, and putative sex differences in the underlying molecular mechanisms through which E2 enhances memory formation. The review concludes by discussing the importance and implications of sex differences in the molecular mechanisms underlying E2-induced memory consolidation for human health.
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Affiliation(s)
- Karyn M Frick
- Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, United States.
| | - Jennifer J Tuscher
- Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, United States
| | - Wendy A Koss
- Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, United States
| | - Jaekyoon Kim
- Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, United States
| | - Lisa R Taxier
- Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, United States
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Linear and inverted U-shaped dose-response functions describe estrogen effects on hippocampal activity in young women. Nat Commun 2018; 9:1220. [PMID: 29572476 PMCID: PMC5865215 DOI: 10.1038/s41467-018-03679-x] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Accepted: 03/02/2018] [Indexed: 01/07/2023] Open
Abstract
In animals, 17-beta-estradiol (E2) enhances hippocampal plasticity in a dose-dependent, monotonically increasing manner, but this relationship can also exhibit an inverted U-shaped function. To investigate E2’s dose-response function in the human hippocampus, we pharmacologically increased E2 levels in 125 naturally cycling women (who were in their low-hormone menstruation phase) to physiological (equivalent to menstrual cycle peak) and supraphysiological (equivalent to levels during early pregnancy) concentrations in a placebo-controlled design. Twenty-four hours after first E2 intake, we measured brain activity during encoding of neutral and negative pictures and then tested recognition memory 24 h after encoding. Here we report that E2 exhibits both a monotonically increasing relationship with hippocampal activity as well as an inverted U-shaped relationship, depending on the hippocampal region. Hippocampal activity exhibiting a U-shaped relationship inflects at supraphysiological E2 levels, suggesting that while E2 within physiological ranges stimulates hippocampal activity, supraphysiological ranges show opposite effects. While estrogen is known to change hippocampal activity in animals, it is not known if this effect extends to humans. Here, authors vary the doses of estrogen in young women and show that the effects on hippocampal activity can be described by linear and inverted-U shaped dose-response functions.
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Increased dendritic length in CA1 and CA3 hippocampal neurons during the metestrus phase in Wistar rats. Brain Res 2018; 1682:78-83. [DOI: 10.1016/j.brainres.2018.01.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 01/02/2018] [Accepted: 01/06/2018] [Indexed: 11/21/2022]
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Murakami G, Hojo Y, Kato A, Komatsuzaki Y, Horie S, Soma M, Kim J, Kawato S. Rapid nongenomic modulation by neurosteroids of dendritic spines in the hippocampus: Androgen, oestrogen and corticosteroid. J Neuroendocrinol 2018; 30. [PMID: 29194818 DOI: 10.1111/jne.12561] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2017] [Revised: 11/24/2017] [Accepted: 11/27/2017] [Indexed: 12/22/2022]
Abstract
Memories are stored in synapses that consist of axon terminals and dendritic spines. Dendritic spines are postsynaptic structures of synapses and are essential for synaptic plasticity and cognition. Therefore, extensive investigations concerning the functions and structures of spines have been performed. Sex steroids and stress steroids have been shown to modulate hippocampal synapses. Although the rapid modulatory action of sex steroids on synapses has been studied in hippocampal neurones over several decades, the essential molecular mechanisms have not been fully understood. Here, a description of kinase-dependent signalling mechanisms is provided that can explain the rapid nongenomic modulation of dendritic spinogenesis in rat and mouse hippocampal slices by the application of sex steroids, including dihydrotestosterone, testosterone, oestradiol and progesterone. We also indicate the role of synaptic (classic) sex steroid receptors that trigger these rapid synaptic modulations. Moreover, we describe rapid nongenomic spine modulation by applying corticosterone, which is an acute stress model of the hippocampus. The explanations for the results obtained are mainly based on the optical imaging of dendritic spines. Comparisons are also performed with results obtained from other types of imaging, including electron microscopic imaging. Relationships between spine modulation and modulation of cognition are discussed. We recognise that most of rapid effects of exogenously applied oestrogen and androgen were observed in steroid-depleted conditions, including acute slices of the hippocampus, castrated male animals and ovariectomised female animals. Therefore, the previously observed effects can be considered as a type of recovery event, which may be essentially similar to hormone replacement therapy under hormone-decreased conditions. On the other hand, in gonadally intact young animals with high levels of endogenous sex hormones, further supplementation of sex hormones might not be effective, whereas the infusion of blockers for steroid receptors or kinases may be effective, with respect to suppressing sex hormone functions, thus providing useful information regarding molecular mechanisms.
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Affiliation(s)
- G Murakami
- Department of Liberal Arts, Faculty of Medicine, Saitama Medical University, Iruma, Saitama, Japan
| | - Y Hojo
- Department of Biochemistry, Faculty of Medicine, Saitama Medical University, Iruma, Saitama, Japan
| | - A Kato
- Department of Biophysics and Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, Meguro, Tokyo, Japan
| | - Y Komatsuzaki
- Department of Physics, College of Science and Technology, Nihon University, Chiyoda, Tokyo, Japan
| | - S Horie
- Department of Urology, Graduate School of Medicine, Juntendo University, Hongo, Tokyo, Japan
| | - M Soma
- Department of Cognitive Neuroscience, Faculty of Pharma-Science, Teikyo University, Itabashi, Tokyo, Japan
| | - J Kim
- Department of Cognitive Neuroscience, Faculty of Pharma-Science, Teikyo University, Itabashi, Tokyo, Japan
| | - S Kawato
- Department of Biophysics and Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, Meguro, Tokyo, Japan
- Department of Urology, Graduate School of Medicine, Juntendo University, Hongo, Tokyo, Japan
- Department of Cognitive Neuroscience, Faculty of Pharma-Science, Teikyo University, Itabashi, Tokyo, Japan
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Wang S, Zhu J, Xu T. 17β-estradiol (E2) promotes growth and stability of new dendritic spines via estrogen receptor β pathway in intact mouse cortex. Brain Res Bull 2017; 137:241-248. [PMID: 29288734 DOI: 10.1016/j.brainresbull.2017.12.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2017] [Revised: 12/01/2017] [Accepted: 12/19/2017] [Indexed: 12/15/2022]
Abstract
The steroid hormone 17β-estradiol (E2) remodels neural circuits at the synaptic level in the mammalian hippocampus and cortex. However, the underlying mechanism of synapse dynamics remains unclear. To elucidate the mechanism, we traced individual dendritic spines on layer V pyramidal neurons of the primary sensory cortex in adult female mice under E2 intervention using two-photon in vivo imaging microscopy. We confirmed the increase of the spine density upon E2 treatment in the intact mouse cortex. Furthermore, we found that this increase is due to the promotion of spine formation and the stability of newly formed spines. E2 treatment doesn't alter the elimination rate of pre-existing spines. Our results also indicate that the activation of the estrogen receptor β (ERβ) mimics the effects of E2 administration on spine dynamics. Taken together, our findings suggest that estrogen promotes growth and stability of new dendritic spines via the ERβ pathway in the intact cortex of female mice.
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Affiliation(s)
- Shaofang Wang
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Wuhan, Hubei 430074, China; MOE Key Laboratory for Biomedical Photonics, Collaborative Innovation Center for Biomedical Engineering, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Jun Zhu
- Chengdu Military General Hospital, Chengdu, China
| | - Tonghui Xu
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Wuhan, Hubei 430074, China; MOE Key Laboratory for Biomedical Photonics, Collaborative Innovation Center for Biomedical Engineering, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China.
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Avila JA, Alliger AA, Carvajal B, Zanca RM, Serrano PA, Luine VN. Estradiol rapidly increases GluA2-mushroom spines and decreases GluA2-filopodia spines in hippocampus CA1. Hippocampus 2017; 27:1224-1229. [PMID: 28833901 PMCID: PMC5744887 DOI: 10.1002/hipo.22768] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 07/18/2017] [Accepted: 08/07/2017] [Indexed: 01/15/2023]
Abstract
Hippocampal dendritic spine density rapidly increases following estradiol (E2 ) treatment, but the types of spines and trafficking of synaptic markers have received little investigation. We assessed rapid effects of E2 over time on the density of four spine types (stubby, filopodial, long thin, and mushroom) and trafficking of AMPA receptor subunit GluA2 and PSD95 on tertiary, apical dendrites in CA1. Castrated male rats received 20 μg kg-1 of E2 or vehicle and were sacrificed 30 or 120 min later. Images of Golgi-Cox impregnated and PSD95/GluA2 stained dendrites were captured under the confocal microscope and quantified with IMARIS-XT. Stubby and filopodial spine densities did not change following treatment. Long-thin spines significantly decreased at 30 min while mushroom spines significantly increased at 120 min. GluA2, PSD95, and GluA2/PSD95 colocalization levels in stubby or long thin spines did not change, but filopodial spines had significantly reduced GluA2 levels at 30 min. Mushroom spines showed significantly increased levels for GluA2, PSD95 and GluA2/PSD95 colocalization at 120 min. Because GluA2 is important for memory consolidation, current results present novel data suggesting that trafficking of GluA2 to mushroom spines provides one mechanism contributing to estradiol's ability to enhance learning and memory by the PI3 signaling pathway.
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Affiliation(s)
- Jorge A Avila
- Department of Psychology, Hunter College, City University of New York, New York
- Behavioral and Cognitive Neuroscience Program, The Graduate Center of CUNY, New York, New York
| | - Amber A Alliger
- Department of Psychology, Hunter College, City University of New York, New York
| | - Brigett Carvajal
- Department of Psychology, Hunter College, City University of New York, New York
| | - Roseanna M Zanca
- Department of Psychology, Hunter College, City University of New York, New York
- Behavioral and Cognitive Neuroscience Program, The Graduate Center of CUNY, New York, New York
| | - Peter A Serrano
- Department of Psychology, Hunter College, City University of New York, New York
- Behavioral and Cognitive Neuroscience Program, The Graduate Center of CUNY, New York, New York
| | - Victoria N Luine
- Department of Psychology, Hunter College, City University of New York, New York
- Behavioral and Cognitive Neuroscience Program, The Graduate Center of CUNY, New York, New York
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Hwang DS, Kim N, Choi JG, Kim HG, Kim H, Oh MS. Dangguijakyak-san ameliorates memory deficits in ovariectomized mice by upregulating hippocampal estrogen synthesis. Altern Ther Health Med 2017; 17:501. [PMID: 29178947 PMCID: PMC5702078 DOI: 10.1186/s12906-017-2015-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 11/17/2017] [Indexed: 01/20/2023]
Abstract
Background Dangguijakyak-san (DJS) is an herbal formulation that has been clinically applicable for treating postmenopausal symptoms and neurological disorders. It is reported that hippocampal estrogen attenuates memory impairment via neuroprotection and synaptogenesis. However, the effect of DJS on hippocampal estrogen synthesis remains unknown. In this study, we explored the effect of DJS and its neuroprotective mechanism against memory impairment in ovariectomized (OVX) mice, with respect to hippocampal estrogen stimulation. Methods Cell cultures were prepared from the hippocampi of 18-day-old embryos from timed pregnant Sprague–Dawley rats. The hippocampi were dissected, collected, dissociated, and plated in 60-mm dishes. The cells were treated with DJS for 48 h and the supernatant was collected to determine estrogen levels. Female ICR mice (8-weeks-old) were housed for 1 week and ovariectomy was performed to remove the influence of ovary-synthesized estrogens. Following a 2-week post-surgical recovery period, the mice were administrated with DJS (50 and 100 mg/kg/day, p.o.) or 17β-estradiol (200 μg/kg/day, i.p.) once daily for 21 days. Hippocampal and serum estrogen levels were determined using enzyme-linked immunosorbent assay kit. Memory behavioral tests, western blot, and immunohistochemical analyses were performed to evaluate the neuroprotective effects of DJS in this model. Results DJS treatment promoted estrogen synthesis in primary hippocampal cells and the hippocampus of OVX mice, resulting in the amelioration of OVX-induced memory impairment. Hippocampal estrogen stimulated by DJS treatment contributed to the activation of cAMP response element-binding protein and synaptic protein in OVX mice. Conclusion DJS may attenuate memory deficits in postmenopausal women via hippocampal estrogen synthesis. Electronic supplementary material The online version of this article (10.1186/s12906-017-2015-6) contains supplementary material, which is available to authorized users.
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Effects of Female Sex Steroids Administration on Pathophysiologic Mechanisms in Traumatic Brain Injury. Transl Stroke Res 2017; 9:393-416. [PMID: 29151229 DOI: 10.1007/s12975-017-0588-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 10/16/2017] [Accepted: 11/07/2017] [Indexed: 12/19/2022]
Abstract
Secondary brain damage following initial brain damage in traumatic brain injury (TBI) is a major cause of adverse outcomes. There are many gaps in TBI research and a lack of therapy to limit debilitating outcomes in TBI or enhance the neurogenesis, despite pre-clinical and clinical research performed in TBI. Females show harmful outcomes against brain damage including TBI less than males, independent of different TBI occurrence. A significant reduction in secondary brain damage and improvement in neurologic outcome post-TBI has been reported following the use of progesterone and estrogen in many experimental studies. Although useful features of sex steroids including progesterone have been identified in TBI clinical trials I and II, clinical trials III have been unsuccessful. This review article focuses on evidence of secondary injury mechanisms and neuroprotective effects of estrogen and progesterone in TBI. Understanding these mechanisms may enable researchers to achieve greater success in TBI clinical studies. It seems that the design of clinical studies should be revised due to translation loss of animal studies to clinical studies. The heterogeneous and complex nature of TBI, the endogenous levels of sex hormones at the time of taking these hormones, the therapeutic window of the drug, the dosage of the drug, the selection of appropriate targets in evaluation, the determination of responsive population, gender and age based on animal studies should be considered in the design of TBI human studies in future.
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Engler-Chiurazzi EB, Brown CM, Povroznik JM, Simpkins JW. Estrogens as neuroprotectants: Estrogenic actions in the context of cognitive aging and brain injury. Prog Neurobiol 2017; 157:188-211. [PMID: 26891883 PMCID: PMC4985492 DOI: 10.1016/j.pneurobio.2015.12.008] [Citation(s) in RCA: 136] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 11/06/2015] [Accepted: 12/10/2015] [Indexed: 12/30/2022]
Abstract
There is ample empirical evidence to support the notion that the biological impacts of estrogen extend beyond the gonads to other bodily systems, including the brain and behavior. Converging preclinical findings have indicated a neuroprotective role for estrogen in a variety of experimental models of cognitive function and brain insult. However, the surprising null or even detrimental findings of several large clinical trials evaluating the ability of estrogen-containing hormone treatments to protect against age-related brain changes and insults, including cognitive aging and brain injury, led to hesitation by both clinicians and patients in the use of exogenous estrogenic treatments for nervous system outcomes. That estrogen-containing therapies are used by tens of millions of women for a variety of health-related applications across the lifespan has made identifying conditions under which benefits with estrogen treatment will be realized an important public health issue. Here we provide a summary of the biological actions of estrogen and estrogen-containing formulations in the context of aging, cognition, stroke, and traumatic brain injury. We have devoted special attention to highlighting the notion that estrogen appears to be a conditional neuroprotectant whose efficacy is modulated by several interacting factors. By developing criteria standards for desired beneficial peripheral and neuroprotective outcomes among unique patient populations, we can optimize estrogen treatments for attenuating the consequences of, and perhaps even preventing, cognitive aging and brain injury.
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Affiliation(s)
- E B Engler-Chiurazzi
- Center for Basic and Translational Stroke Research, West Virginia University, Morgantown, WV 26506, United States; Department of Physiology and Pharmacology, West Virginia University, Morgantown, WV 26506, United States.
| | - C M Brown
- Center for Basic and Translational Stroke Research, West Virginia University, Morgantown, WV 26506, United States; Department of Neurobiology and Anatomy, West Virginia University, Morgantown, WV 26506, United States.
| | - J M Povroznik
- Center for Basic and Translational Stroke Research, West Virginia University, Morgantown, WV 26506, United States; Department of Pediatrics, West Virginia University, Morgantown, WV 26506, United States.
| | - J W Simpkins
- Center for Basic and Translational Stroke Research, West Virginia University, Morgantown, WV 26506, United States; Department of Physiology and Pharmacology, West Virginia University, Morgantown, WV 26506, United States.
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Sbisa AM, Gogos A, van den Buuse M. Spatial working memory in the touchscreen operant platform is disrupted in female rats by ovariectomy but not estrous cycle. Neurobiol Learn Mem 2017; 144:147-154. [PMID: 28729138 DOI: 10.1016/j.nlm.2017.07.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 05/31/2017] [Accepted: 07/15/2017] [Indexed: 12/12/2022]
Abstract
Learning and memory deficits have been described in rats and mice after ovariectomy (OVX) and across the estrous cycle. Preclinical researchers therefore often avoid using female animals and, consequently, a large male bias exists in the preclinical cognitive literature. In the present study we examined the role of sex hormones in the touchscreen operant platform using the spatial working memory trial unique nonmatching-to-location (TUNL) task. Twenty-nine Long Evans rats were trained to acquire the TUNL task including three incremental spatial separations (S0, S1, S2). Following 20 consecutive days of training, subjects in experiment 1 (n=15) remained intact and immediately progressed to TUNL testing, while subjects in experiment 2 were OVX (n=6) or sham-operated (n=8) prior to testing. Subjects were tested on 4 spatial separations (S0-3) with a 1s or 6s delay between the sample and nonmatching stimuli. The estrous cycle of intact rats was monitored during the 4weeks of testing. The estrous cycle phase did not significantly affect performance. In contrast, compared to intact rats, OVX impaired performance at larger spatial separations (S2-3) during the 1s delay condition. Further, during the 6s delay, OVX impaired S2 performance, however not S3. Our results suggest a probable shift in cognitive strategy following OVX, when tested with a large and novel spatial separation. Our findings suggest that ovarian hormone deprivation following OVX, but not estrous cycle, impairs spatial working memory as measured by the TUNL task. This research is relevant for future studies utilising the touchscreen TUNL task and for cognitive testing of female rats.
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Affiliation(s)
- Alyssa M Sbisa
- Hormones in Psychiatry Laboratory, The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Victoria, Australia; School of Psychology and Public Health, La Trobe University, Bundoora, Victoria, Australia
| | - Andrea Gogos
- Hormones in Psychiatry Laboratory, The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Victoria, Australia
| | - Maarten van den Buuse
- School of Psychology and Public Health, La Trobe University, Bundoora, Victoria, Australia; Department of Pharmacology, University of Melbourne, Victoria, Australia; The College of Public Health, Medical and Veterinary Sciences, James Cook University, Queensland, Australia.
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50
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Lymer J, Robinson A, Winters BD, Choleris E. Rapid effects of dorsal hippocampal G-protein coupled estrogen receptor on learning in female mice. Psychoneuroendocrinology 2017; 77:131-140. [PMID: 28033587 DOI: 10.1016/j.psyneuen.2016.11.019] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 10/18/2016] [Accepted: 11/16/2016] [Indexed: 10/20/2022]
Abstract
Through rapid mechanisms of action, estrogens affect learning and memory processes. It has been shown that 17β-estradiol and an Estrogen Receptor (ER) α agonist enhances performance in social recognition, object recognition, and object placement tasks when administered systemically or infused in the dorsal hippocampus. In contrast, systemic and dorsal hippocampal ERβ activation only promote spatial learning. In addition, 17β-estradiol, the ERα and the G-protein coupled estrogen receptor (GPER) agonists increase dendritic spine density in the CA1 hippocampus. Recently, we have shown that selective systemic activation of the GPER also rapidly facilitated social recognition, object recognition, and object placement learning in female mice. Whether activation the GPER specifically in the dorsal hippocampus can also rapidly improve learning and memory prior to acquisition is unknown. Here, we investigated the rapid effects of infusion of the GPER agonist, G-1 (dose: 50nM, 100nM, 200nM), in the dorsal hippocampus on social recognition, object recognition, and object placement learning tasks in home cage. These paradigms were completed within 40min, which is within the range of rapid estrogenic effects. Dorsal hippocampal administration of G-1 improved social (doses: 50nM, 200nM G-1) and object (dose: 200nM G-1) recognition with no effect on object placement. Additionally, when spatial cues were minimized by testing in a Y-apparatus, G-1 administration promoted social (doses: 100nM, 200nM G-1) and object (doses: 50nM, 100nM, 200nM G-1) recognition. Therefore, like ERα, the GPER in the hippocampus appears to be sufficient for the rapid facilitation of social and object recognition in female mice, but not for the rapid facilitation of object placement learning. Thus, the GPER in the dorsal hippocampus is involved in estrogenic mediation of learning and memory and these effects likely occur through rapid signalling mechanisms.
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Affiliation(s)
- Jennifer Lymer
- Department of Psychology and Neuroscience Program, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - Alana Robinson
- Department of Psychology and Neuroscience Program, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - Boyer D Winters
- Department of Psychology and Neuroscience Program, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - Elena Choleris
- Department of Psychology and Neuroscience Program, University of Guelph, Guelph, ON N1G 2W1, Canada.
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