1
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Gall CM, Le AA, Lynch G. Contributions of site- and sex-specific LTPs to everyday memory. Philos Trans R Soc Lond B Biol Sci 2024; 379:20230223. [PMID: 38853551 DOI: 10.1098/rstb.2023.0223] [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: 10/23/2023] [Accepted: 03/06/2024] [Indexed: 06/11/2024] Open
Abstract
Commentaries about long-term potentiation (LTP) generally proceed with an implicit assumption that largely the same physiological effect is sampled across different experiments. However, this is clearly not the case. We illustrate the point by comparing LTP in the CA3 projections to CA1 with the different forms of potentiation in the dentate gyrus. These studies lead to the hypothesis that specialized properties of CA1-LTP are adaptations for encoding unsupervised learning and episodic memory, whereas the dentate gyrus variants subserve learning that requires multiple trials and separation of overlapping bodies of information. Recent work has added sex as a second and somewhat surprising dimension along which LTP is also differentiated. Triggering events for CA1-LTP differ between the sexes and the adult induction threshold is significantly higher in females; these findings help explain why males have an advantage in spatial learning. Remarkably, the converse is true before puberty: Females have the lower LTP threshold and are better at spatial memory problems. A mechanism has been identified for the loss-of-function in females but not for the gain-of-function in males. We propose that the many and disparate demands of natural environments, with different processing requirements across ages and between sexes, led to the emergence of multiple LTPs. This article is part of a discussion meeting issue 'Long-term potentiation: 50 years on'.
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Affiliation(s)
- Christine M Gall
- Department of Anatomy and Neurobiology, University of California at Irvine , Irvine, CA 92697, USA
- Department of Neurobiology and Behavior, University of California at Irvine , Irvine, CA 92697, USA
| | - Aliza A Le
- Department of Anatomy and Neurobiology, University of California at Irvine , Irvine, CA 92697, USA
| | - Gary Lynch
- Department of Anatomy and Neurobiology, University of California at Irvine , Irvine, CA 92697, USA
- Department of Psychiatry and Human Behavior, University of California at Irvine , Irvine, CA 92868, USA
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2
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Mamczarz J, Lane M, Merchenthaler I. Letrozole delays acquisition of water maze task in female BALB/c mice: Possible involvement of anxiety. Horm Behav 2024; 162:105524. [PMID: 38513526 DOI: 10.1016/j.yhbeh.2024.105524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 02/25/2024] [Accepted: 02/28/2024] [Indexed: 03/23/2024]
Abstract
Letrozole, an aromatase inhibitor preventing estrogen synthesis from testosterone, is used as an adjuvant therapy in estrogen receptor-positive breast cancer patients. However, like other aromatase inhibitors, it induces many side effects, including impaired cognition. Despite its negative effect in humans, results from animal models are inconsistent and suggest that letrozole can either impair or improve cognition. Here, we studied the effects of chronic letrozole treatment on cognitive behavior of adult female BALB/c mice, a relevant animal model for breast cancer studies, to develop an appropriate animal model aimed at testing therapies to mitigate side effects of letrozole. In Morris water maze, letrozole 0.1 mg/kg impaired reference learning and memory. Interestingly, most of the letrozole 0.1 mg/kg-treated mice were able to learn the new platform position in reversal training and performed similar to control mice in a reversal probe test. Results of the reversal test suggest that letrozole did not completely disrupt spatial navigation, but rather delayed acquisition of spatial information. The delay might be related to increased anxiety as suggested by increased thigmotactic behavior during the reference memory training. The learning impairment was water maze-specific since we did not observe impairment in other spatial tasks such as in Y-maze or object location test. In contrast, the dose of 0.3 mg/kg did not have effect on water maze learning and facilitated locomotor habituation and recognition in novel object recognition test. The current study shows that letrozole dose-dependently modulates behavioral response and that its effects are task-dependent.
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Affiliation(s)
- Jacek Mamczarz
- Division of Translational Toxicology, Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, MD 21201, United States of America.
| | - Malcolm Lane
- Department of Anatomy & Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, United States of America
| | - Istvan Merchenthaler
- Division of Translational Toxicology, Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, MD 21201, United States of America; Department of Anatomy & Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, United States of America
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3
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Moors TE, Li S, McCaffery TD, Ho GP, Bechade PA, Pham LN, Ericsson M, Nuber S. Increased palmitoylation improves estrogen receptor alpha-dependent hippocampal synaptic deficits in a mouse model of synucleinopathy. SCIENCE ADVANCES 2023; 9:eadj1454. [PMID: 37976363 PMCID: PMC10957154 DOI: 10.1126/sciadv.adj1454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Accepted: 10/18/2023] [Indexed: 11/19/2023]
Abstract
Parkinson's disease (PD) is characterized by conversion of soluble α-synuclein (αS) into intraneuronal aggregates and degeneration of neurons and neuronal processes. Indications that women with early-stage PD display milder neurodegenerative features suggest that female sex partially protects against αS pathology. We previously reported that female sex and estradiol improved αS homeostasis and PD-like phenotypes in E46K-amplified (3K) αS mice. Here, we aimed to further dissect mechanisms that drive this sex dimorphism early in disease. We observed that synaptic abnormalities were delayed in females and improved by estradiol, mediated by local estrogen receptor alpha (ERα). Aberrant ERα distribution in 3K compared to wild-type mice was paired with its decreased palmitoylation. Treatment with ML348, a de-palmitoylation inhibitor, increased ERα availability and soluble αS homeostasis, ameliorating synaptic plasticity and cognitive and motor phenotypes. Our finding that sex differences in early-disease αS-induced synaptic impairment in 3KL mice are in part mediated by palmitoylated ERα may have functional and pathogenic implications for clinical PD.
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Affiliation(s)
- Tim E. Moors
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Shaomin Li
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Thomas D. McCaffery
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Gary P. H. Ho
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Pascal A. Bechade
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Luu N. Pham
- Laboratory for Drug Discovery in Neurodegeneration, Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Maria Ericsson
- Electron Microscopy Laboratory, Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Silke Nuber
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
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4
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Garcia-Segura LM, Méndez P, Arevalo MA, Azcoitia I. Neuroestradiol and neuronal development: Not an exclusive male tale anymore. Front Neuroendocrinol 2023; 71:101102. [PMID: 37689249 DOI: 10.1016/j.yfrne.2023.101102] [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: 07/26/2023] [Revised: 09/04/2023] [Accepted: 09/06/2023] [Indexed: 09/11/2023]
Abstract
The brain synthesizes a variety of neurosteroids, including neuroestradiol. Inhibition of neuroestradiol synthesis results in alterations in basic neurodevelopmental processes, such as neurogenesis, neuroblast migration, neuritogenesis and synaptogenesis. Although the neurodevelopmental actions of neuroestradiol are exerted in both sexes, some of them are sex-specific, such as the well characterized effects of neuroestradiol derived from the metabolism of testicular testosterone during critical periods of male brain development. In addition, recent findings have shown sex-specific actions of neuroestradiol on neuroblast migration, neuritic growth and synaptogenesis in females. Among other factors, the epigenetic regulation exerted by X linked genes, such as Kdm6a/Utx, may determine sex-specific actions of neuroestradiol in the female brain. This review evidences the impact of neuroestradiol on brain formation in both sexes and highlights the interaction of neural steriodogenesis, hormones and sex chromosomes in sex-specific brain development.
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Affiliation(s)
- Luis M Garcia-Segura
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC), Avenida Doctor Arce 37, 28002 Madrid, Spain; Centro de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable (CIBERFES), Instituto Nacional de Salud Carlos III, Madrid, Spain.
| | - Pablo Méndez
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC), Avenida Doctor Arce 37, 28002 Madrid, Spain
| | - M Angeles Arevalo
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC), Avenida Doctor Arce 37, 28002 Madrid, Spain; Centro de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable (CIBERFES), Instituto Nacional de Salud Carlos III, Madrid, Spain.
| | - Iñigo Azcoitia
- Centro de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable (CIBERFES), Instituto Nacional de Salud Carlos III, Madrid, Spain; Department of Cell Biology, Universidad Complutense de Madrid, C José Antonio Nováis 12, 28040 Madrid, Spain
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5
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Kim SR, Eom Y, Lee SH. Comprehensive analysis of sex differences in the function and ultrastructure of hippocampal presynaptic terminals. Neurochem Int 2023; 169:105570. [PMID: 37451344 DOI: 10.1016/j.neuint.2023.105570] [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: 01/25/2023] [Revised: 05/08/2023] [Accepted: 07/04/2023] [Indexed: 07/18/2023]
Abstract
Sex differences in the brain, encompassing variations in specific brain structures, size, cognitive function, and synaptic connections, have been identified across numerous species. While previous research has explored sex differences in postsynaptic structures, synaptic plasticity, and hippocampus-dependent functions, the hippocampal presynaptic terminals remain largely uninvestigated. The hippocampus is a critical structure responsible for multiple brain functions. This study examined presynaptic differences in cultured hippocampal neurons derived from male and female mice using a combination of biochemical assays, functional analyses measuring exocytosis and endocytosis of synaptic vesicle proteins, ultrastructural analyses via electron microscopy, and presynaptic Ca2+-specific optical probes. Our findings revealed that female neurons exhibited a higher number of synaptic vesicles at presynaptic terminals compared to male neurons. However, no significant differences were observed in presynaptic protein expression, presynaptic terminal ultrastructure, synaptic vesicle exocytosis and endocytosis, or presynaptic Ca2+ alterations between male and female neurons.
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Affiliation(s)
- Sung Rae Kim
- College of Pharmacy, Chung-Ang University, Seoul 06974, Republic of Korea; Brain Research Core Facilities of Korea Brain Research Institute (KBRI), Daegu 41068, Republic of Korea.
| | - Yunkyung Eom
- College of Pharmacy, Chung-Ang University, Seoul 06974, Republic of Korea.
| | - Sung Hoon Lee
- College of Pharmacy, Chung-Ang University, Seoul 06974, Republic of Korea.
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6
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Lewitus VJ, Blackwell KT. Estradiol Receptors Inhibit Long-Term Potentiation in the Dorsomedial Striatum. eNeuro 2023; 10:ENEURO.0071-23.2023. [PMID: 37487741 PMCID: PMC10405883 DOI: 10.1523/eneuro.0071-23.2023] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 05/25/2023] [Accepted: 06/19/2023] [Indexed: 07/26/2023] Open
Abstract
Estradiol, a female sex hormone and the predominant form of estrogen, has diverse effects throughout the brain including in learning and memory. Estradiol modulates several types of learning that depend on the dorsomedial striatum (DMS), a subregion of the basal ganglia involved in goal-directed learning, cued action-selection, and motor skills. A cellular basis of learning is synaptic plasticity, and the presence of extranuclear estradiol receptors ERα, ERβ, and G-protein-coupled estrogen receptor (GPER) throughout the DMS suggests that estradiol may influence rapid cellular actions including those involved in plasticity. To test whether estradiol affects synaptic plasticity in the DMS, corticostriatal long-term potentiation (LTP) was induced using theta-burst stimulation (TBS) in ex vivo brain slices from intact male and female C57BL/6 mice. Extracellular field recordings showed that female mice in the diestrous stage of the estrous cycle exhibited LTP similar to male mice, while female mice in estrus did not exhibit LTP. Furthermore, antagonists of ERα or GPER rescued LTP in estrous females and agonists of ERα or GPER reduced LTP in diestrous females. In males, activating ERα but not GPER reduced LTP. These results uncover an inhibitory action of estradiol receptors on cellular learning in the DMS and suggest a cellular mechanism underlying the impairment in certain types of DMS-based learning observed in the presence of high estradiol. Because of the dorsal striatum's role in substance use disorders, these findings may provide a mechanism underlying an estradiol-mediated progression from goal-directed to habitual drug use.
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Affiliation(s)
| | - Kim T Blackwell
- Interdisciplinary Neuroscience PhD Program
- Department of Bioengineering, George Mason University, Fairfax, VA 22030
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7
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Velasco ER, Florido A, Perez-Caballero L, Marin I, Andero R. The Impacts of Sex Differences and Sex Hormones on Fear Extinction. Curr Top Behav Neurosci 2023; 64:105-132. [PMID: 37528309 DOI: 10.1007/7854_2023_426] [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] [Indexed: 08/03/2023]
Abstract
Fear extinction memories are strongly modulated by sex and hormonal status, but the exact mechanisms are still being discovered. In humans, there are some basal and task-related features in which male and female individuals differ in fear conditioning paradigms. However, analyses considering the effects of sex hormones demonstrate a role for estradiol in fear extinction memory consolidation. Translational studies are taking advantage of the convergent findings between species to understand the brain structures implicated. Nevertheless, the human brain is complex and the transfer of these findings into the clinics remains a challenge. The promising advances in the field together with the standardization of fear extinction methodologies in humans will benefit the design of new personalized therapies.
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Affiliation(s)
- Eric Raul Velasco
- Institut de Neurociències, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Antonio Florido
- Institut de Neurociències, Universitat Autònoma de Barcelona, Barcelona, Spain
- Departament de Psicobiologia i de Metodologia de les Ciències de la Salut, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Laura Perez-Caballero
- Institut de Neurociències, Universitat Autònoma de Barcelona, Barcelona, Spain
- Departament de Psicobiologia i de Metodologia de les Ciències de la Salut, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Ignacio Marin
- Institut de Neurociències, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Raul Andero
- Institut de Neurociències, Universitat Autònoma de Barcelona, Barcelona, Spain.
- Departament de Psicobiologia i de Metodologia de les Ciències de la Salut, Universitat Autònoma de Barcelona, Barcelona, Spain.
- Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Instituto de Salud Carlos III, Madrid, Spain.
- Unitat de Neurociència Traslacional, Parc Taulí Hospital Universitari, Institut d'Investigació i Innovació Parc Taulí (I3PT), Institut de Neurociències, Universitat Autònoma de Barcelona, Bellaterra, Spain.
- ICREA, Pg. Lluís Companys 23, Barcelona, Spain.
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8
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Edwards M, Lam S, Ranjan R, Pereira M, Babbitt C, Lacreuse A. Letrozole treatment alters hippocampal gene expression in common marmosets (Callithrix jacchus). Horm Behav 2023; 147:105281. [PMID: 36434852 PMCID: PMC9839488 DOI: 10.1016/j.yhbeh.2022.105281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Revised: 10/28/2022] [Accepted: 11/09/2022] [Indexed: 11/25/2022]
Abstract
Aromatase inhibitors (AIs) are a class of drugs commonly given to patients with estrogen receptor (ER)-dependent breast cancers to reduce estrogenic stimulation. However, AIs like Letrozole are associated with negative side effects such as cognitive deficits, sleep disturbances and hot flashes. We have previously shown that these negative effects can be recapitulated in common marmosets (Callithrix jacchus) treated with Letrozole (20 μg daily) for 4 weeks and that marmosets treated with Letrozole show increased levels of estradiol in the hippocampus (Gervais et al., 2019). In order to better understand the mechanisms through which AIs affect cognitive function and increase steroid levels in the hippocampus, we used bulk, paired-end RNA-sequencing to examine differentially expressed genes among Letrozole-treated (LET; n = 8) and vehicle-treated (VEH; n = 8) male and female animals. Gene ontology results show significant reduction across hundreds of categories, some of the most significant being inflammatory response, stress response, MHC Class II protein complex binding, T-cell activation, carbohydrate binding and signaling receptor binding in LET animals. GSEA results indicate that LET females, but not LET males, show enrichment for hormonal gene sets. Based on the transcriptional changes observed, we conclude that AIs may differentially affect the sexes in part due to processes mediated by the CYP-450 superfamily. Ongoing studies will further investigate the longitudinal effects of AIs on behavior and whether AIs increase the risk of stress-induced neurodegeneration.
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Affiliation(s)
- Mélise Edwards
- University of Massachusetts Amherst, Department of Psychological & Brain Sciences, Amherst, MA 01003, USA; Neuroscience and Behavior Graduate Program, University of Massachusetts, Amherst, MA 01003, USA.
| | - Sam Lam
- University of Massachusetts Amherst, Department of Psychological & Brain Sciences, Amherst, MA 01003, USA
| | - Ravi Ranjan
- University of Massachusetts Amherst, Department of Psychological & Brain Sciences, Amherst, MA 01003, USA; Genomics Resource Laboratory, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Mariana Pereira
- University of Massachusetts Amherst, Department of Psychological & Brain Sciences, Amherst, MA 01003, USA; Neuroscience and Behavior Graduate Program, University of Massachusetts, Amherst, MA 01003, USA
| | - Courtney Babbitt
- University of Massachusetts Amherst, Department of Psychological & Brain Sciences, Amherst, MA 01003, USA; University of Massachusetts Amherst, Department of Biology, Amherst, MA 01003, USA
| | - Agnès Lacreuse
- University of Massachusetts Amherst, Department of Psychological & Brain Sciences, Amherst, MA 01003, USA; Neuroscience and Behavior Graduate Program, University of Massachusetts, Amherst, MA 01003, USA
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9
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Estradiol and Estrogen-like Alternative Therapies in Use: The Importance of the Selective and Non-Classical Actions. Biomedicines 2022; 10:biomedicines10040861. [PMID: 35453610 PMCID: PMC9029610 DOI: 10.3390/biomedicines10040861] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 04/03/2022] [Accepted: 04/04/2022] [Indexed: 12/17/2022] Open
Abstract
Estrogen is one of the most important female sex hormones, and is indispensable for reproduction. However, its role is much wider. Among others, due to its neuroprotective effects, estrogen protects the brain against dementia and complications of traumatic injury. Previously, it was used mainly as a therapeutic option for influencing the menstrual cycle and treating menopausal symptoms. Unfortunately, hormone replacement therapy might be associated with detrimental side effects, such as increased risk of stroke and breast cancer, raising concerns about its safety. Thus, tissue-selective and non-classical estrogen analogues have become the focus of interest. Here, we review the current knowledge about estrogen effects in a broader sense, and the possibility of using selective estrogen-receptor modulators (SERMs), selective estrogen-receptor downregulators (SERDs), phytoestrogens, and activators of non-genomic estrogen-like signaling (ANGELS) molecules as treatment.
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10
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Maksimovic S, Useinovic N, Quillinan N, Covey DF, Todorovic SM, Jevtovic-Todorovic V. General Anesthesia and the Young Brain: The Importance of Novel Strategies with Alternate Mechanisms of Action. Int J Mol Sci 2022; 23:ijms23031889. [PMID: 35163810 PMCID: PMC8836828 DOI: 10.3390/ijms23031889] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 02/04/2022] [Accepted: 02/05/2022] [Indexed: 12/10/2022] Open
Abstract
Over the past three decades, we have been grappling with rapidly accumulating evidence that general anesthetics (GAs) may not be as innocuous for the young brain as we previously believed. The growing realization comes from hundreds of animal studies in numerous species, from nematodes to higher mammals. These studies argue that early exposure to commonly used GAs causes widespread apoptotic neurodegeneration in brain regions critical to cognition and socio-emotional development, kills a substantial number of neurons in the young brain, and, importantly, results in lasting disturbances in neuronal synaptic communication within the remaining neuronal networks. Notably, these outcomes are often associated with long-term impairments in multiple cognitive-affective domains. Not only do preclinical studies clearly demonstrate GA-induced neurotoxicity when the exposures occur in early life, but there is a growing body of clinical literature reporting similar cognitive-affective abnormalities in young children who require GAs. The need to consider alternative GAs led us to focus on synthetic neuroactive steroid analogues that have emerged as effective hypnotics, and analgesics that are apparently devoid of neurotoxic effects and long-term cognitive impairments. This would suggest that certain steroid analogues with different cellular targets and mechanisms of action may be safe alternatives to currently used GAs. Herein we summarize our current knowledge of neuroactive steroids as promising novel GAs.
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Affiliation(s)
- Stefan Maksimovic
- Department of Anesthesiology, Anschutz Medical Campus, University of Colorado, Aurora, CO 80045, USA; (N.U.); (N.Q.); (S.M.T.); (V.J.-T.)
- Correspondence:
| | - Nemanja Useinovic
- Department of Anesthesiology, Anschutz Medical Campus, University of Colorado, Aurora, CO 80045, USA; (N.U.); (N.Q.); (S.M.T.); (V.J.-T.)
| | - Nidia Quillinan
- Department of Anesthesiology, Anschutz Medical Campus, University of Colorado, Aurora, CO 80045, USA; (N.U.); (N.Q.); (S.M.T.); (V.J.-T.)
- Neuronal Injury and Plasticity Program, Anschutz Medical Campus, University of Colorado, Aurora, CO 80045, USA
| | - Douglas F. Covey
- Department of Developmental Biology, Washington University in St. Louis School of Medicine, St. Louis, MO 63110, USA;
- Taylor Family Institute for Innovative Psychiatric Research, Washington University in St. Louis School of Medicine, St. Louis, MO 63110, USA
| | - Slobodan M. Todorovic
- Department of Anesthesiology, Anschutz Medical Campus, University of Colorado, Aurora, CO 80045, USA; (N.U.); (N.Q.); (S.M.T.); (V.J.-T.)
| | - Vesna Jevtovic-Todorovic
- Department of Anesthesiology, Anschutz Medical Campus, University of Colorado, Aurora, CO 80045, USA; (N.U.); (N.Q.); (S.M.T.); (V.J.-T.)
- Department of Pharmacology, Anschutz Medical Campus, University of Colorado, Aurora, CO 80045, USA
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11
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Manzella FM, Covey DF, Jevtovic-Todorovic V, Todorovic SM. Synthetic neuroactive steroids as new sedatives and anaesthetics: Back to the future. J Neuroendocrinol 2022; 34:e13086. [PMID: 35014105 PMCID: PMC8866223 DOI: 10.1111/jne.13086] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 12/03/2021] [Accepted: 12/22/2021] [Indexed: 02/03/2023]
Abstract
Since the 1990s, there has been waning interest in researching general anaesthetics (anaesthetics). Although currently used anaesthetics are mostly safe and effective, they are not without fault. In paediatric populations and neonatal animal models, they are associated with learning impairments and neurotoxicity. In an effort to research safer anaesthetics, we have gone back to re-examine neuroactive steroids as anaesthetics. Neuroactive steroids are steroids that have direct, local effects in the central nervous system. Since the discovery of their anaesthetic effects, neuroactive steroids have been consistently used in human or veterinary clinics as preferred anaesthetic agents. Although briefly abandoned for clinical use due to unwanted vehicle side effects, there has since been renewed interest in their therapeutic value. Neuroactive steroids are safe sedative/hypnotic and anaesthetic agents across various animal species. Importantly, unlike traditional anaesthetics, they do not cause extensive neurotoxicity in the developing rodent brain. Similar to traditional anaesthetics, neuroactive steroids are modulators of synaptic and extrasynaptic γ-aminobutyric acid type A (GABAA ) receptors and their interactions at the GABAA receptor are stereo- and enantioselective. Recent work has also shown that these agents act on other ion channels, such as high- and low-voltage-activated calcium channels. Through these mechanisms of action, neuroactive steroids modulate neuronal excitability, which results in characteristic burst suppression of the electroencephalogram, and a surgical plane of anaesthesia. However, in addition to their interactions with voltage and ligand gated ions channels, neuroactive steroids interact with membrane bound metabotropic receptors and xenobiotic receptors to facilitate signaling of prosurvival, antiapoptotic pathways. These pathways play a role in their neuroprotective effects in neuronal injury and may also prevent extensive apoptosis in the developing brain during anaesthesia. The current review explores the history of neuroactive steroids as anaesthetics in humans and animal models, their diverse mechanisms of action, and their neuroprotective properties.
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Affiliation(s)
- Francesca M Manzella
- Department of Anesthesiology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
- Neuroscience Graduate Program, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Douglas F Covey
- Department of Developmental Biology, Washington University in St. Louis School of Medicine, St. Louis, Missouri, USA
- Taylor Family Institute for Innovative Psychiatric Research, Washington University in St. Louis School of Medicine, St. Louis, Missouri, USA
| | - Vesna Jevtovic-Todorovic
- Department of Anesthesiology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Slobodan M Todorovic
- Department of Anesthesiology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
- Neuroscience Graduate Program, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
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12
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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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13
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Brann DW, Lu Y, Wang J, Sareddy GR, Pratap UP, Zhang Q, Tekmal RR, Vadlamudi RK. Neuron-Derived Estrogen-A Key Neuromodulator in Synaptic Function and Memory. Int J Mol Sci 2021; 22:ijms222413242. [PMID: 34948039 PMCID: PMC8706511 DOI: 10.3390/ijms222413242] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 11/29/2021] [Accepted: 12/04/2021] [Indexed: 01/31/2023] Open
Abstract
In addition to being a steroid hormone, 17β-estradiol (E2) is also a neurosteroid produced in neurons in various regions of the brain of many species, including humans. Neuron-derived E2 (NDE2) is synthesized from androgen precursors via the action of the biosynthetic enzyme aromatase, which is located at synapses and in presynaptic terminals in neurons in both the male and female brain. In this review, we discuss evidence supporting a key role for NDE2 as a neuromodulator that regulates synaptic plasticity and memory. Evidence supporting an important neuromodulatory role of NDE2 in the brain has come from studies using aromatase inhibitors, aromatase overexpression in neurons, global aromatase knockout mice, and the recent development of conditional forebrain neuron-specific knockout mice. Collectively, these studies demonstrate a key role of NDE2 in the regulation of synapse and spine density, efficacy of excitatory synaptic transmission and long-term potentiation, and regulation of hippocampal-dependent recognition memory, spatial reference memory, and contextual fear memory. NDE2 is suggested to achieve these effects through estrogen receptor-mediated regulation of rapid kinase signaling and CREB-BDNF signaling pathways, which regulate actin remodeling, as well as transcription, translation, and transport of synaptic proteins critical for synaptic plasticity and function.
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Affiliation(s)
- Darrell W. Brann
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA;
- Correspondence:
| | - Yujiao Lu
- Department of Neurosurgery, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA;
| | - Jing Wang
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA;
| | - Gangadhara R. Sareddy
- Department of Obstetrics and Gynecology, University of Texas Health, San Antonio, TX 78229, USA; (G.R.S.); (U.P.P.); (R.R.T.); (R.K.V.)
| | - Uday P. Pratap
- Department of Obstetrics and Gynecology, University of Texas Health, San Antonio, TX 78229, USA; (G.R.S.); (U.P.P.); (R.R.T.); (R.K.V.)
| | - Quanguang Zhang
- Department of Neurology, Louisiana State University Health, Shreveport, LA 71103, USA;
| | - Rajeshwar R. Tekmal
- Department of Obstetrics and Gynecology, University of Texas Health, San Antonio, TX 78229, USA; (G.R.S.); (U.P.P.); (R.R.T.); (R.K.V.)
| | - Ratna K. Vadlamudi
- Department of Obstetrics and Gynecology, University of Texas Health, San Antonio, TX 78229, USA; (G.R.S.); (U.P.P.); (R.R.T.); (R.K.V.)
- Audie L. Murphy Division, South Texas Veterans Health Care System, San Antonio, TX 78229, USA
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14
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Brann DW, Lu Y, Wang J, Zhang Q, Thakkar R, Sareddy GR, Pratap UP, Tekmal RR, Vadlamudi RK. Brain-derived estrogen and neural function. Neurosci Biobehav Rev 2021; 132:793-817. [PMID: 34823913 PMCID: PMC8816863 DOI: 10.1016/j.neubiorev.2021.11.014] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 10/26/2021] [Accepted: 11/12/2021] [Indexed: 01/02/2023]
Abstract
Although classically known as an endocrine signal produced by the ovary, 17β-estradiol (E2) is also a neurosteroid produced in neurons and astrocytes in the brain of many different species. In this review, we provide a comprehensive overview of the localization, regulation, sex differences, and physiological/pathological roles of brain-derived E2 (BDE2). Much of what we know regarding the functional roles of BDE2 has come from studies using specific inhibitors of the E2 synthesis enzyme, aromatase, as well as the recent development of conditional forebrain neuron-specific and astrocyte-specific aromatase knockout mouse models. The evidence from these studies support a critical role for neuron-derived E2 (NDE2) in the regulation of synaptic plasticity, memory, socio-sexual behavior, sexual differentiation, reproduction, injury-induced reactive gliosis, and neuroprotection. Furthermore, we review evidence that astrocyte-derived E2 (ADE2) is induced following brain injury/ischemia, and plays a key role in reactive gliosis, neuroprotection, and cognitive preservation. Finally, we conclude by discussing the key controversies and challenges in this area, as well as potential future directions for the field.
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Affiliation(s)
- Darrell W Brann
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA, 30912, USA.
| | - Yujiao Lu
- Department of Neurosurgery, Medical College of Georgia, Augusta University, Augusta, GA, 30912, USA
| | - Jing Wang
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA, 30912, USA
| | - Quanguang Zhang
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA, 30912, USA
| | - Roshni Thakkar
- Department of Neurology, Miller School of Medicine, University of Miami, Miami, FL, 33136, USA
| | - Gangadhara R Sareddy
- Department of Obstetrics and Gynecology, University of Texas Health, San Antoio TX, 78229, USA
| | - Uday P Pratap
- Department of Obstetrics and Gynecology, University of Texas Health, San Antoio TX, 78229, USA
| | - Rajeshwar R Tekmal
- Department of Obstetrics and Gynecology, University of Texas Health, San Antoio TX, 78229, USA
| | - Ratna K Vadlamudi
- Department of Obstetrics and Gynecology, University of Texas Health, San Antoio TX, 78229, USA; Audie L. Murphy Division, South Texas Veterans Health Care System, San Antonio, TX, 78229, USA.
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15
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Shaw GA, Hyer MM, Dustin E, Dyer SK, Targett IL, Neigh GN. Acute LPS exposure increases synaptosomal metabolism during estrus but not diestrus. Physiol Behav 2021; 239:113523. [PMID: 34229031 DOI: 10.1016/j.physbeh.2021.113523] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 06/09/2021] [Accepted: 06/30/2021] [Indexed: 11/15/2022]
Abstract
The hormones estrogen and progesterone alter physiological functions, including the estrus cycle and relevant neurological and synaptic activity. Here, we determined the extent to which estrus cycle stage interacts with an inflammatory stimulus, lipopolysaccharide (LPS), to alter synaptic mitochondrial respiration in female rats. LPS elevated synaptic mitochondrial respiration of rats in estrus, but not diestrus. Likewise, estrogen concentration correlated with multiple respiratory metrics in LPS treated females in estrus. These data suggest estrogen likely modulates synaptic mitochondrial respiration in a high progesterone environment.
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Affiliation(s)
- Gladys A Shaw
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, 1101 East Marshall Street, Box 980709, Richmond, VA 23298, United States
| | - Molly M Hyer
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, 1101 East Marshall Street, Box 980709, Richmond, VA 23298, United States
| | - Elizabeth Dustin
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, 1101 East Marshall Street, Box 980709, Richmond, VA 23298, United States
| | - Samya K Dyer
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, 1101 East Marshall Street, Box 980709, Richmond, VA 23298, United States
| | - Imogen L Targett
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, 1101 East Marshall Street, Box 980709, Richmond, VA 23298, United States
| | - Gretchen N Neigh
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, 1101 East Marshall Street, Box 980709, Richmond, VA 23298, United States.
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16
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Brandt N, Vierk R, Fester L, Anstötz M, Zhou L, Heilmann LF, Kind S, Steffen P, Rune GM. Sex-specific Difference of Hippocampal Synaptic Plasticity in Response to Sex Neurosteroids. Cereb Cortex 2021; 30:2627-2641. [PMID: 31800024 DOI: 10.1093/cercor/bhz265] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 08/23/2019] [Accepted: 09/17/2019] [Indexed: 12/14/2022] Open
Abstract
Numerous studies provide increasing evidence, which supports the ideas that every cell in the brain of males may differ from those in females due to differences in sex chromosome complement as well as in response to hormonal effects. In this study, we address the question as to whether actions of neurosteroids, thus steroids, which are synthesized and function within the brain, contribute to sex-specific hippocampal synaptic plasticity. We have previously shown that predominantly in the female hippocampus, does inhibition of the conversion of testosterone to estradiol affect synaptic transmission. In this study, we show that testosterone and its metabolite dihydrotestosterone are essential for hippocampal synaptic transmission specifically in males. This also holds true for the density of mushroom spines and of spine synapses. We obtained similar sex-dependent results using primary hippocampal cultures of male and female animals. Since these cultures originated from perinatal animals, our findings argue for sex-dependent differentiation of hippocampal neurons regarding their responsiveness to sex neurosteroids up to birth, which persist during adulthood. Hence, our in vitro findings may point to a developmental effect either directly induced by sex chromosomes or indirectly by fetal testosterone secretion during the perinatal critical period, when developmental sexual priming takes place.
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Affiliation(s)
- Nicola Brandt
- Institute of Neuroanatomy, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Ricardo Vierk
- Institute of Neuroanatomy, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Lars Fester
- Institute of Neuroanatomy, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Max Anstötz
- Institute of Neuroanatomy, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Lepu Zhou
- Institute of Neuroanatomy, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Lukas F Heilmann
- Institute of Neuroanatomy, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Simon Kind
- Institute of Neuroanatomy, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Paul Steffen
- Institute of Neuroanatomy, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Gabriele M Rune
- Institute of Neuroanatomy, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
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17
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Sex neurosteroids: Hormones made by the brain for the brain. Neurosci Lett 2021; 753:135849. [PMID: 33775739 DOI: 10.1016/j.neulet.2021.135849] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 03/09/2021] [Accepted: 03/22/2021] [Indexed: 11/21/2022]
Abstract
In general, hippocampal neurons are capable of synthesizing sex steroids de novo from cholesterol, since the brain is equipped with all the enzymes required for the synthesis of estradiol and testosterone, the end products of sex steroidogenesis. Regarding estradiol, its synthesis in hippocampal neurons is homeostatically controlled by Ca2+ transients and is regulated by GnRH. Locally synthesized estradiol and testosterone maintain synaptic transmission and synaptic connectivity. Remarkably, the neurosteroid estradiol is effective in females, but not in males, and vice versa dihydrotestosterone (DHT) is effective in males, but not in females. Experimentally induced inhibition of estradiol synthesis in females and DHT synthesis in males resp. results in synapse loss, impaired LTP, and downregulation of synaptic proteins. GnRH-induced increase in estradiol synthesis appears to provide a link between the hypothalamus and the hippocampus, which may underlie estrous cyclicity of spine density in the female hippocampus. Hippocampal neurons are sex-dependently differentiated with respect to the responsiveness of hippocampal neurons to sex neurosteroids.
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18
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Effects of oral contraceptive pills on mood and magnetic resonance imaging measures of prefrontal cortical thickness. Mol Psychiatry 2021; 26:917-926. [PMID: 33420480 PMCID: PMC7914152 DOI: 10.1038/s41380-020-00990-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 11/23/2020] [Accepted: 12/07/2020] [Indexed: 01/29/2023]
Abstract
Gonadal hormones influence neuronal organization and plasticity. Yet the consequences of altering their concentrations by administering contraceptive agents, which are used by most reproductive-age women in the United States, are unclear. Cross-sectional studies have found both larger and smaller cortical regions alongside a variety of mood alterations in women who use oral contraceptive pills (OCPs) compared to naturally-cycling women. The goal of this study, therefore, was to determine whether there is an effect of OCPs on MRI measures of prefrontal cortical brain structure that may influence regulation of mood. We performed a double-blind, placebo-controlled, randomized crossover study comparing effects of OCPs (0.15 mg levonorgestrel + 0.30 μg ethinyl estradiol) vs placebo (N = 26) on MRI measures of prefrontal cortical thickness and on mood, as indicated by self-report on the Daily Record of Severity of Problems, which also includes one item related to somatic symptoms. MRI measures that reflect cortical thickness were smaller bilaterally in the pars triangularis and in the pars opercularis and frontal pole of the right hemisphere during the OCP arm vs. placebo. Only the effect in the right pars triangularis survived multiple comparisons correction. Right pars triangularis MRI measures of cortical thickness were not related to mood symptoms, but negatively correlated across conditions with severity of somatic symptoms on the DSRP. The somatic symptoms and MRI measures may be independently related to the actions of steroid hormones in OCPs, with OCPs simultaneously inducing both more effects on MRI measures of cortical thickness and somatic symptoms.
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19
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Yap K, Drakew A, Smilovic D, Rietsche M, Paul MH, Vuksic M, Del Turco D, Deller T. The actin-modulating protein synaptopodin mediates long-term survival of dendritic spines. eLife 2020; 9:e62944. [PMID: 33275099 PMCID: PMC7717903 DOI: 10.7554/elife.62944] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Accepted: 11/14/2020] [Indexed: 12/15/2022] Open
Abstract
Large spines are stable and important for memory trace formation. The majority of large spines also contains synaptopodin (SP), an actin-modulating and plasticity-related protein. Since SP stabilizes F-actin, we speculated that the presence of SP within large spines could explain their long lifetime. Indeed, using 2-photon time-lapse imaging of SP-transgenic granule cells in mouse organotypic tissue cultures we found that spines containing SP survived considerably longer than spines of equal size without SP. Of note, SP-positive (SP+) spines that underwent pruning first lost SP before disappearing. Whereas the survival time courses of SP+ spines followed conditional two-stage decay functions, SP-negative (SP-) spines and all spines of SP-deficient animals showed single-phase exponential decays. This was also the case following afferent denervation. These results implicate SP as a major regulator of long-term spine stability: SP clusters stabilize spines, and the presence of SP indicates spines of high stability.
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Affiliation(s)
- Kenrick Yap
- Institute of Clinical Neuroanatomy, Dr. Senckenberg Anatomy, Neuroscience Center, Goethe University FrankfurtFrankfurtGermany
| | - Alexander Drakew
- Institute of Clinical Neuroanatomy, Dr. Senckenberg Anatomy, Neuroscience Center, Goethe University FrankfurtFrankfurtGermany
| | - Dinko Smilovic
- Institute of Clinical Neuroanatomy, Dr. Senckenberg Anatomy, Neuroscience Center, Goethe University FrankfurtFrankfurtGermany
- Croatian Institute for Brain Research, School of Medicine, University of ZagrebZagrebCroatia
| | - Michael Rietsche
- Institute of Clinical Neuroanatomy, Dr. Senckenberg Anatomy, Neuroscience Center, Goethe University FrankfurtFrankfurtGermany
| | - Mandy H Paul
- Institute of Clinical Neuroanatomy, Dr. Senckenberg Anatomy, Neuroscience Center, Goethe University FrankfurtFrankfurtGermany
| | - Mario Vuksic
- Institute of Clinical Neuroanatomy, Dr. Senckenberg Anatomy, Neuroscience Center, Goethe University FrankfurtFrankfurtGermany
- Croatian Institute for Brain Research, School of Medicine, University of ZagrebZagrebCroatia
| | - Domenico Del Turco
- Institute of Clinical Neuroanatomy, Dr. Senckenberg Anatomy, Neuroscience Center, Goethe University FrankfurtFrankfurtGermany
| | - Thomas Deller
- Institute of Clinical Neuroanatomy, Dr. Senckenberg Anatomy, Neuroscience Center, Goethe University FrankfurtFrankfurtGermany
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20
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Marbouti L, Zahmatkesh M, Riahi E, Sadr SS. Inhibition of brain 17β-estradiol synthesis by letrozole induces cognitive decline in male and female rats. Neurobiol Learn Mem 2020; 175:107300. [PMID: 32882397 DOI: 10.1016/j.nlm.2020.107300] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 08/17/2020] [Accepted: 08/24/2020] [Indexed: 10/23/2022]
Abstract
BACKGROUND Hippocampal aromatase is responsible for local synthesis of 17β-estradiol (E2) that has much higher concentrations than serum levels in males and females. Letrozole, an aromatase inhibitor, passes through the brain barriers, distributes to the brain, and affects local E2 synthesis. Here, the effects of intra-cerebroventricular (ICV) letrozole administration in the presence and absence of gonads were examined on the cognitive abilities of male and female rats. METHOD Animals received intra-ICV injection of letrozole or vehicle for 14 consecutive days. Spatial working memory, novel object recognition memory, and anxiety-related behavior, were evaluated using Y-maze, object recognition test, and elevated plus maze, respectively. The E2 levels in the serum and hippocampal tissue were measured by the ELISA technique. RT-PCR was performed to assess the hippocampal estrogen receptors (ER) expression. Moreover, letrozole effect on neuronal activity of CA1 pyramidal neurons was studied by in vivo single-unit recording. RESULTS Letrozole (0.2, 0.4, and 0.8 µg) significantly decreased the hippocampal E2 levels compared to the vehicle group. Letrozole caused cognitive impairments in a dose-dependent manner in male and female rats in the presence or absence of gonads. Dose-response analysis revealed that the minimum effective dose of letrozole on the behavioral measures was 0.4 μg. Letrozole also caused an up-regulation of ERα and ERβ and a down-regulation of GPR30 gene expression. The firing rate of pyramidal neurons was reduced by letrozole in gonadal-intact animals. CONCLUSION The detrimental effects of letrozole treatment on cognitive abilities in the presence and absence of gonads indicate that local E2 synthesis in the hippocampus is a crucial factor in normal cognitive performance. The suppressive effect of letrozole on hippocampal neuronal firing might alter synaptic plasticity that is critical for memory formation. These data potentially suggest that memory deficits following letrozole administration should be monitored.
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Affiliation(s)
- Ladan Marbouti
- Electrophysiology Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran; Neuroscience and Addiction Studies Department, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Maryam Zahmatkesh
- Electrophysiology Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran; Neuroscience and Addiction Studies Department, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran; Cognitive and Behavioral Sciences Research Center, Tehran University of Medical Sciences, Tehran, Iran.
| | - Esmail Riahi
- Physiology Department, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Seyed Shahabeddin Sadr
- Electrophysiology Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran; Physiology Department, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
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21
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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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22
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Brandt N, Fester L, Rune GM. Neural sex steroids and hippocampal synaptic plasticity. VITAMINS AND HORMONES 2020; 114:125-143. [PMID: 32723541 DOI: 10.1016/bs.vh.2020.06.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
It was a widely held belief that sex steroids, namely testosterone and 17β-estradiol (E2) of gonadal origin, control synaptic plasticity in the hippocampus. A new paradigm emerged when it was shown that these sex steroids are synthesized in the hippocampus. The inhibition of sex steroids in the hippocampus impairs synaptic plasticity sex-dependently in this region of the brain. In gonadectomized animals and in hippocampal cultures, inhibition of estradiol synthesis in female animals and in cultures from female animals, and inhibition of dihydrotestosterone synthesis in male animals and in cultures of male animals, cause synapse loss and impair LTP in the hippocampus, but not vice versa. Since the hippocampal cultures originated from perinatal animals, and due to the similarity of in vivo and in vitro findings, it appears that hippocampal neurons are differentiated in a sex-specific manner during the perinatal period when sexual imprinting takes place.
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Affiliation(s)
- N Brandt
- Center of Experimental Medicine, Institute of Neuroanatomy, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - L Fester
- Center of Experimental Medicine, Institute of Neuroanatomy, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - G M Rune
- Center of Experimental Medicine, Institute of Neuroanatomy, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
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23
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Vegeto E, Villa A, Della Torre S, Crippa V, Rusmini P, Cristofani R, Galbiati M, Maggi A, Poletti A. The Role of Sex and Sex Hormones in Neurodegenerative Diseases. Endocr Rev 2020; 41:5572525. [PMID: 31544208 PMCID: PMC7156855 DOI: 10.1210/endrev/bnz005] [Citation(s) in RCA: 99] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 09/20/2019] [Indexed: 12/11/2022]
Abstract
Neurodegenerative diseases (NDs) are a wide class of disorders of the central nervous system (CNS) with unknown etiology. Several factors were hypothesized to be involved in the pathogenesis of these diseases, including genetic and environmental factors. Many of these diseases show a sex prevalence and sex steroids were shown to have a role in the progression of specific forms of neurodegeneration. Estrogens were reported to be neuroprotective through their action on cognate nuclear and membrane receptors, while adverse effects of male hormones have been described on neuronal cells, although some data also suggest neuroprotective activities. The response of the CNS to sex steroids is a complex and integrated process that depends on (i) the type and amount of the cognate steroid receptor and (ii) the target cell type-either neurons, glia, or microglia. Moreover, the levels of sex steroids in the CNS fluctuate due to gonadal activities and to local metabolism and synthesis. Importantly, biochemical processes involved in the pathogenesis of NDs are increasingly being recognized as different between the two sexes and as influenced by sex steroids. The aim of this review is to present current state-of-the-art understanding on the potential role of sex steroids and their receptors on the onset and progression of major neurodegenerative disorders, namely, Alzheimer's disease, Parkinson's diseases, amyotrophic lateral sclerosis, and the peculiar motoneuron disease spinal and bulbar muscular atrophy, in which hormonal therapy is potentially useful as disease modifier.
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Affiliation(s)
- Elisabetta Vegeto
- Center of Excellence on Neurodegenerative Diseases, Università degli Studi di Milano, Italy.,Dipartimento di Scienze Farmaceutiche (DiSFarm), Università degli Studi di Milano, Italy
| | - Alessandro Villa
- Center of Excellence on Neurodegenerative Diseases, Università degli Studi di Milano, Italy.,Dipartimento di Scienze della Salute (DiSS), Università degli Studi di Milano, Italy
| | - Sara Della Torre
- Center of Excellence on Neurodegenerative Diseases, Università degli Studi di Milano, Italy.,Dipartimento di Scienze Farmaceutiche (DiSFarm), Università degli Studi di Milano, Italy
| | - Valeria Crippa
- Center of Excellence on Neurodegenerative Diseases, Università degli Studi di Milano, Italy.,Dipartimento di Eccellenza di Scienze Farmacologiche e Biomolecolari (DiSFeB), Università degli Studi di Milano, Italy
| | - Paola Rusmini
- Center of Excellence on Neurodegenerative Diseases, Università degli Studi di Milano, Italy.,Dipartimento di Eccellenza di Scienze Farmacologiche e Biomolecolari (DiSFeB), Università degli Studi di Milano, Italy
| | - Riccardo Cristofani
- Center of Excellence on Neurodegenerative Diseases, Università degli Studi di Milano, Italy.,Dipartimento di Eccellenza di Scienze Farmacologiche e Biomolecolari (DiSFeB), Università degli Studi di Milano, Italy
| | - Mariarita Galbiati
- Center of Excellence on Neurodegenerative Diseases, Università degli Studi di Milano, Italy.,Dipartimento di Eccellenza di Scienze Farmacologiche e Biomolecolari (DiSFeB), Università degli Studi di Milano, Italy
| | - Adriana Maggi
- Center of Excellence on Neurodegenerative Diseases, Università degli Studi di Milano, Italy.,Dipartimento di Scienze Farmaceutiche (DiSFarm), Università degli Studi di Milano, Italy
| | - Angelo Poletti
- Center of Excellence on Neurodegenerative Diseases, Università degli Studi di Milano, Italy.,Dipartimento di Eccellenza di Scienze Farmacologiche e Biomolecolari (DiSFeB), Università degli Studi di Milano, Italy
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24
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Vaillant C, Gueguen MM, Feat J, Charlier TD, Coumailleau P, Kah O, Brion F, Pellegrini E. Neurodevelopmental effects of natural and synthetic ligands of estrogen and progesterone receptors in zebrafish eleutheroembryos. Gen Comp Endocrinol 2020; 288:113345. [PMID: 31812531 DOI: 10.1016/j.ygcen.2019.113345] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 11/03/2019] [Accepted: 11/26/2019] [Indexed: 12/31/2022]
Abstract
Natural and synthetic estrogens and progestins are widely used in human and veterinary medicine and are detected in waste and surface waters. Our previous studies have clearly shown that a number of these substances targets the brain to induce the estrogen-regulated brain aromatase expression but the consequences on brain development remain virtually unexplored. The aim of the present study was therefore to investigate the effect of estradiol (E2), progesterone (P4) and norethindrone (NOR), a 19-nortestosterone progestin, on zebrafish larval neurogenesis. We first demonstrated using real-time quantitative PCR that nuclear estrogen and progesterone receptor brain expression is impacted by E2, P4 and NOR. We brought evidence that brain proliferative and apoptotic activities were differentially affected depending on the steroidal hormone studied, the concentration of steroids and the region investigated. Our findings demonstrate for the first time that steroid compounds released in aquatic environment have the capacity to disrupt key cellular events involved in brain development in zebrafish embryos further questioning the short- and long-term consequences of this disruption on the physiology and behavior of organisms.
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Affiliation(s)
- Colette Vaillant
- Univ Rennes, Inserm, EHESP, Irset (Institut de recherche en santé, environnement et travail) - UMR_S 1085, F-35000 Rennes, France
| | - Marie-Madeleine Gueguen
- Univ Rennes, Inserm, EHESP, Irset (Institut de recherche en santé, environnement et travail) - UMR_S 1085, F-35000 Rennes, France
| | - Justyne Feat
- Univ Rennes, Inserm, EHESP, Irset (Institut de recherche en santé, environnement et travail) - UMR_S 1085, F-35000 Rennes, France
| | - Thierry D Charlier
- Univ Rennes, Inserm, EHESP, Irset (Institut de recherche en santé, environnement et travail) - UMR_S 1085, F-35000 Rennes, France
| | - Pascal Coumailleau
- Univ Rennes, Inserm, EHESP, Irset (Institut de recherche en santé, environnement et travail) - UMR_S 1085, F-35000 Rennes, France
| | - Olivier Kah
- Univ Rennes, Inserm, EHESP, Irset (Institut de recherche en santé, environnement et travail) - UMR_S 1085, F-35000 Rennes, France
| | - François Brion
- Institut National de l'Environnement Industriel et des Risques INERIS, Unité d'Ecotoxicologie, 60550, Verneuil-en-Halatte, France
| | - Elisabeth Pellegrini
- Univ Rennes, Inserm, EHESP, Irset (Institut de recherche en santé, environnement et travail) - UMR_S 1085, F-35000 Rennes, France.
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25
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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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26
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The Impact of Estradiol on Neurogenesis and Cognitive Functions in Alzheimer's Disease. Cell Mol Neurobiol 2019; 40:283-299. [PMID: 31502112 DOI: 10.1007/s10571-019-00733-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 08/31/2019] [Indexed: 12/18/2022]
Abstract
Alzheimer's disease (AD) is described as cognitive and memory impairments with a sex-related epidemiological profile, affecting two times more women than men. There is emerging evidence that alternations in the hippocampal neurogenesis occur at the early stage of AD. Therapies that may effectively slow, stop, or regenerate the dying neurons in AD are being extensively investigated in the last few decades, but none has yet been found to be effective. The regulation of endogenous neurogenesis is one of the main therapeutic targets for AD. Mounting evidence indicates that the neurosteroid estradiol (17β-estradiol) plays a supporting role in neurogenesis, neuronal activity, and synaptic plasticity of AD. This effect may provide preventive and/or therapeutic approaches for AD. In this article, we discuss the molecular mechanism of potential estradiol modulatory action on endogenous neurogenesis, synaptic plasticity, and cognitive function in AD.
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27
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Brandt N, Rune GM. Sex-dependency of oestrogen-induced structural synaptic plasticity: Inhibition of aromatase versus application of estradiol in rodents. Eur J Neurosci 2019; 52:2548-2559. [PMID: 31403726 DOI: 10.1111/ejn.14541] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 07/19/2019] [Accepted: 08/01/2019] [Indexed: 12/21/2022]
Abstract
Sex-dependent differences in learning and memory formation in humans have been frequently shown. The mechanisms underlying the formation and retention of memories are assumed to involve synaptic plasticity in the hippocampus. Estradiol was shown to effect synaptic plasticity in the hippocampus of rodents. The effects after exogenous application of estradiol to animals frequently produce inconsistent results, in particular, if sex is not considered in the studies. Recently we provided evidence that locally synthesized estradiol plays an essential role on synaptic connectivity in the hippocampus of females but not of male mice. In females, inhibition of local estradiol synthesis leads to synapse loss, which results from impairment of long-term potentiation and dephosphorylation of cofilin, and thereby the destabilization of postsynaptic dendritic spines. This sex-dependency was also seen in the classical aromatase knock-out mouse. Intriguingly, no differences between sexes have been found in a conditional forebrain-specific aromatase knock-out mouse. Altogether, the findings underscore the necessity of including 'Sex as a Biological Variable' in studies of sex steroid-induced synaptic plasticity.
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Affiliation(s)
- Nicola Brandt
- Institute of Neuroanatomy, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Gabriele M Rune
- Institute of Neuroanatomy, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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28
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Jeon S, Kang JM, Seo S, Jeong HJ, Funck T, Lee SY, Park KH, Lee YB, Yeon BK, Ido T, Okamura N, Evans AC, Na DL, Noh Y. Topographical Heterogeneity of Alzheimer's Disease Based on MR Imaging, Tau PET, and Amyloid PET. Front Aging Neurosci 2019; 11:211. [PMID: 31481888 PMCID: PMC6710378 DOI: 10.3389/fnagi.2019.00211] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 07/26/2019] [Indexed: 11/13/2022] Open
Abstract
Alzheimer’s disease (AD) patients are known to have heterogeneous clinical presentation and pathologic patterns. We hypothesize that AD dementia can be categorized into subtypes based on multimodal imaging biomarkers such as magnetic resonance imaging (MRI), tau positron emission tomography (PET), and amyloid PET. We collected 3T MRI, 18F-THK5351 PET, and 18F-flutemetamol (FLUTE) PET data from 83 patients with AD dementia [Clinical Dementia Rating (CDR) ≤1] and 60 normal controls (NC), and applied surface-based analyses to measure cortical thickness, THK5351 standardized uptake value ratio (SUVR) and FLUTE SUVR for each participant. For the patient group, we performed an agglomerative hierarchical clustering analysis using the three multimodal imaging features on the vertices (n = 3 × 79,950). The identified AD subtypes were compared to NC using general linear models adjusting for age, sex, and years of education. We mapped the effect size within significant cortical regions reaching a corrected p-vertex <0.05 (random field theory). Our surface-based multimodal framework has revealed three distinct subtypes among AD patients: medial temporal-dominant subtype (MT, n = 44), parietal-dominant subtype (P, n = 19), and diffuse atrophy subtype (D, n = 20). The topography of cortical atrophy and THK5351 retention differentiates between the three subtypes. In the case of FLUTE, three subtypes did not show distinct topographical differences, although cortical composite retention was significantly higher in the P type than in the MT type. These three subtypes also differed in demographic and clinical features. In conclusion, AD patients may be clustered into three subtypes with distinct topographical features of cortical atrophy and tau deposition, although amyloid deposition may not differ across the subtypes in terms of topography.
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Affiliation(s)
- Seun Jeon
- McGill Centre for Integrative Neuroscience, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - Jae Myeong Kang
- Department of Psychiatry, Gil Medical Center, Gachon University College of Medicine, Incheon, South Korea
| | - Seongho Seo
- Department of Neuroscience, Gachon University College of Medicine, Incheon, South Korea
| | - Hye Jin Jeong
- Neuroscience Research Institute, Gachon University, Incheon, South Korea
| | - Thomas Funck
- McGill Centre for Integrative Neuroscience, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - Sang-Yoon Lee
- Department of Neuroscience, Gachon University College of Medicine, Incheon, South Korea
| | - Kee Hyung Park
- Department of Neurology, Gil Medical Center, Gachon University College of Medicine, Incheon, South Korea
| | - Yeong-Bae Lee
- Department of Neurology, Gil Medical Center, Gachon University College of Medicine, Incheon, South Korea
| | - Byeong Kil Yeon
- Department of Psychiatry, Gil Medical Center, Gachon University College of Medicine, Incheon, South Korea
| | - Tatsuo Ido
- Neuroscience Research Institute, Gachon University, Incheon, South Korea
| | - Nobuyuki Okamura
- Division of Pharmacology, Faculty of Medicine, Tohoku Medical and Pharmaceutical University, Sendai, Japan
| | - Alan C Evans
- McGill Centre for Integrative Neuroscience, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - Duk L Na
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.,Neuroscience Center, Samsung Medical Center, Seoul, South Korea
| | - Young Noh
- Department of Neurology, Gil Medical Center, Gachon University College of Medicine, Incheon, South Korea.,Department of Health Science and Technology, GAIHST, Gachon University, Incheon, South Korea
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29
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Trivino-Paredes JS, Nahirney PC, Pinar C, Grandes P, Christie BR. Acute slice preparation for electrophysiology increases spine numbers equivalently in the male and female juvenile hippocampus: a DiI labeling study. J Neurophysiol 2019; 122:958-969. [PMID: 31268808 DOI: 10.1152/jn.00332.2019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Hippocampal slices are widely used for in vitro electrophysiological experiments to study underlying mechanisms for synaptic transmission and plasticity, and there is a growing appreciation for sex differences in synaptic plasticity. To date, several studies have shown that the process of making slices from male animals can induce synaptogenesis in cornu ammonis area 1 (CA1) pyramidal cells, but there is a paucity of data for females and other brain regions. In the current study we use microcrystals of the lipophilic carbocyanine dye DiI (1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate) to stain individual neurons in the CA1 and dentate gyrus (DG) hippocampal subfields of postnatal day 21 male and female rats. We show that the preparation of sections for electrophysiology produces significant increases in spines in sections obtained from females, similar to that observed in males. We also show that the procedures used for in vitro electrophysiology also result in significant spine increases in the DG and CA1 subfields. These results demonstrate the utility of this refined DiI procedure for staining neuronal dendrites and spines. They also show, for the first time, that in vitro electrophysiology slice preparations enhance spine numbers on hippocampal cells equivalently in both juvenile females and males.NEW & NOTEWORTHY This study introduces a new DiI technique that elucidates differences in spine numbers in juvenile female and male hippocampus, and shows that slice preparations for hippocampal electrophysiology in vitro may mask these differences.
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Affiliation(s)
- J S Trivino-Paredes
- Division of Medical Sciences, University of Victoria, Victoria, British Columbia, Canada
| | - P C Nahirney
- Division of Medical Sciences, University of Victoria, Victoria, British Columbia, Canada.,Island Medical Program, University of British Columbia, Victoria, British Columbia, Canada.,Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - C Pinar
- Division of Medical Sciences, University of Victoria, Victoria, British Columbia, Canada
| | - P Grandes
- Division of Medical Sciences, University of Victoria, Victoria, British Columbia, Canada.,Department of Neurosciences, Faculty of Medicine and Nursing, University of the Basque Country UPV/EHU, Leioa, Vizcaya, Spain.,Achucarro Basque Center for Neuroscience, Science Park of the UPV/EHU, Leioa, Vizcaya, Spain
| | - B R Christie
- Division of Medical Sciences, University of Victoria, Victoria, British Columbia, Canada.,Island Medical Program, University of British Columbia, Victoria, British Columbia, Canada.,Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia, Canada
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30
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Possible Existence of the Hypothalamic-Pituitary-Hippocampal (HPH) Axis: A Reciprocal Relationship Between Hippocampal Specific Neuroestradiol Synthesis and Neuroblastosis in Ageing Brains with Special Reference to Menopause and Neurocognitive Disorders. Neurochem Res 2019; 44:1781-1795. [PMID: 31254250 DOI: 10.1007/s11064-019-02833-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 05/13/2019] [Accepted: 06/19/2019] [Indexed: 12/18/2022]
Abstract
The hippocampus-derived neuroestradiol plays a major role in neuroplasticity, independent of circulating estradiol that originates from gonads. The response of hypothalamus-pituitary regions towards the synthesis of neuroestradiol in the hippocampus is an emerging scientific concept in cognitive neuroscience. Hippocampal plasticity has been proposed to be regulated via neuroblasts, a major cellular determinant of functional neurogenesis in the adult brain. Defects in differentiation, integration and survival of neuroblasts in the hippocampus appear to be an underlying cause of neurocognitive disorders. Gonadotropin receptors and steroidogenic enzymes have been found to be expressed in neuroblasts in the hippocampus of the brain. However, the reciprocal relationship between hippocampal-specific neuroestradiol synthesis along neuroblastosis and response of pituitary based feedback regulation towards regulation of estradiol level in the hippocampus have not completely been ascertained. Therefore, this conceptual article revisits (1) the cellular basis of neuroestradiol synthesis (2) a potential relationship between neuroestradiol synthesis and neuroblastosis in the hippocampus (3) the possible involvement of aberrant neuroestradiol production with mitochondrial dysfunctions and dyslipidemia in menopause and adult-onset neurodegenerative disorders and (4) provides a hypothesis for the possible existence of the hypothalamic-pituitary-hippocampal (HPH) axis in the adult brain. Eventually, understanding the regulation of hippocampal neurogenesis by abnormal levels of neuroestradiol concentration in association with the feedback regulation of HPH axis might provide additional cues to establish a neuroregenerative therapeutic management for mood swings, depression and cognitive decline in menopause and neurocognitive disorders.
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31
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Koss WA, Frick KM. Activation of androgen receptors protects intact male mice from memory impairments caused by aromatase inhibition. Horm Behav 2019; 111:96-104. [PMID: 30653980 PMCID: PMC6527464 DOI: 10.1016/j.yhbeh.2019.01.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 12/21/2018] [Accepted: 01/10/2019] [Indexed: 12/17/2022]
Abstract
Although 17β-estradiol (E2) is known to regulate hippocampal function, the specific contributions of hippocampally-synthesized E2 remain unclear. Infusion of the aromatase inhibitor letrozole into the dorsal hippocampus (DH) of ovariectomized mice disrupts object recognition and object placement memory consolidation, suggesting that DH-synthesized E2 is essential for memory. However, the role of DH-synthesized E2 in memory among male rodents is unknown. Here, we examined effects of aromatase inhibition on memory consolidation in male mice. Intact and gonadectomized mice were infused with vehicle or letrozole into the DH immediately post-training in object placement and object recognition tasks. Letrozole blocked memory in both tasks among gonadectomized males only, suggesting that circulating androgens, or a rise in hippocampal androgens due to aromatase inhibition, may support memory consolidation in intact males. To test this hypothesis, intact males were infused with the androgen receptor antagonist flutamide into the DH after object training. A dose-dependent impairment was observed in both tasks, indicating that blocking androgen signaling can impair memory consolidation. To test if hippocampal androgen receptor activation protected intact males from the impairing effects of letrozole, a non-impairing dose of flutamide was co-infused with letrozole. Co-administration of both drugs blocked object placement and object recognition memory consolidation, demonstrating that letrozole impairs memory in intact males only if androgen receptors are blocked. Together, these data suggest that DH-synthesized E2 and androgen receptor activation may work in concert to mediate memory consolidation in intact males, such that androgen receptor activation protects against memory impairments caused by aromatase inhibition.
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Affiliation(s)
- Wendy A Koss
- Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, United States of America.
| | - Karyn M Frick
- Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, United States of America.
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32
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Additive neuroprotective effects of 24(S)-hydroxycholesterol and allopregnanolone in an ex vivo rat glaucoma model. Sci Rep 2018; 8:12851. [PMID: 30150786 PMCID: PMC6110753 DOI: 10.1038/s41598-018-31239-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Accepted: 08/15/2018] [Indexed: 11/25/2022] Open
Abstract
In a rat ex vivo acute glaucoma model, high pressure (75 mmHg) causes swelling of ganglion cell axons and elevates levels of the endogenous steroids 24(S)-hydroxycholesterol (24SH) and allopregnanolone (AlloP). Furthermore, 24SH (0.1 µM) alone elevates AlloP levels via NMDA receptors. With this model, we now investigate possible interactions between 24SH and AlloP. We found that inhibition of AlloP synthesis with dutasteride under high pressure results in severe excitotoxicity in addition to axonal swelling. The excitotoxicity is prevented by exogenous AlloP but not 24SH, indicating that endogenous AlloP is crucial for protection. However, inhibition of 24SH synthesis with voriconazole induces severe excitotoxicity under normal pressure. Paradoxically, the excitotoxicity by voriconazole is better prevented by AlloP than 24SH. These findings suggest that inhibition of 24SH synthesis becomes excitotoxic in the absence of AlloP. We also observed that co-administration of sub-micromolar 24SH (0.1 µM) and AlloP (0.1 µM), concentrations that are only partially effective when administered alone, prevents axonal swelling under high pressure. This apparent enhanced protection indicates strong interaction between the two neurosteroids to preserve neuronal integrity, with 24SH contributing to AlloP synthesis via NMDA receptors and with AlloP playing an essential role in neuroprotection via GABAA receptors.
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33
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Grković I, Mitrović N, Dragić M, Adžić M, Drakulić D, Nedeljković N. Spatial Distribution and Expression of Ectonucleotidases in Rat Hippocampus After Removal of Ovaries and Estradiol Replacement. Mol Neurobiol 2018; 56:1933-1945. [PMID: 29978426 DOI: 10.1007/s12035-018-1217-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Accepted: 06/29/2018] [Indexed: 01/14/2023]
Abstract
Purinergic signaling is the main synaptic and non-synaptic signaling system in brain. ATP acts as a fast excitatory transmitter, while adenosine sets a global inhibitory tone within hippocampal neuronal networks. ATP and adenosine are interconnected by ectonucleotidase enzymes, which convert ATP to adenosine. Existing data point to the converging roles of ovarian steroids and purinergic signaling in synapse formation and refinement and synapse activity in the hippocampus. Therefore, in the present study, we have used enzyme histochemistry and expression analysis to obtain data on spatial distribution and expression of ecto-enzymes NTPDase1, NTPDase2, and ecto-5'-nucleotidase (eN) after removal of ovaries (OVX) and estradiol replacement (E2) in female rat hippocampus. The results show that target ectonucleotidases are predominantly localized in synapse-rich hippocampal layers. The most represented NTPDase in the hippocampal tissue is NTPDase2, being at the same time the mostly affected ectonucleotidase by OVX and E2. Specifically, OVX decreases the expression of NTPDase2 and eN, whereas E2 restores their expression to control level. Impact of OVX and E2 on ectonucleotidase expression was also examined in purified synaptosome (SYN) and gliosome (GLIO) fractions. Data reveal that SYN expresses NTPDase1 and NTPDase2, both of which are reduced following OVX and restored with E2. GLIO exhibits NTPDase2-mediated ATP hydrolysis, which falls in OVX, and recovers by E2. These changes in the activity occur without parallel changes in NTPDase2-protein abundance. The same holds for eN. The lack of correlation between NTPDase2 and eN activities and their respective protein abundances suggest a non-genomic mode of E2 action, which is studied further in primary astrocyte culture. Since ovarian steroids shape hippocampal synaptic networks and regulate ectonucleotidase activities, it is possible that cognitive deficits seen after ovary removal may arise from the loss of E2 modulatory actions on ectonucleotidase expression in the hippocampus.
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Affiliation(s)
- Ivana Grković
- Department of Molecular Biology and Endocrinology, Vinča Institute of Nuclear Sciences, University of Belgrade, Mike Petrovića Alasa 12-14, Belgrade, 11001, Serbia.
| | - Nataša Mitrović
- Department of Molecular Biology and Endocrinology, Vinča Institute of Nuclear Sciences, University of Belgrade, Mike Petrovića Alasa 12-14, Belgrade, 11001, Serbia
| | - Milorad Dragić
- Department of Molecular Biology and Endocrinology, Vinča Institute of Nuclear Sciences, University of Belgrade, Mike Petrovića Alasa 12-14, Belgrade, 11001, Serbia
- Department for General Physiology and Biophysics, Faculty of Biology, University of Belgrade, Studentski trg 3, Belgrade, 11001, Serbia
| | - Marija Adžić
- Department for General Physiology and Biophysics, Faculty of Biology, University of Belgrade, Studentski trg 3, Belgrade, 11001, Serbia
| | - Dunja Drakulić
- Department of Molecular Biology and Endocrinology, Vinča Institute of Nuclear Sciences, University of Belgrade, Mike Petrovića Alasa 12-14, Belgrade, 11001, Serbia
| | - Nadežda Nedeljković
- Department for General Physiology and Biophysics, Faculty of Biology, University of Belgrade, Studentski trg 3, Belgrade, 11001, Serbia
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34
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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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35
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Neural-derived estradiol regulates brain plasticity. J Chem Neuroanat 2018; 89:53-59. [DOI: 10.1016/j.jchemneu.2017.04.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Revised: 03/16/2017] [Accepted: 04/12/2017] [Indexed: 01/12/2023]
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36
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Diotel N, Charlier TD, Lefebvre d'Hellencourt C, Couret D, Trudeau VL, Nicolau JC, Meilhac O, Kah O, Pellegrini E. Steroid Transport, Local Synthesis, and Signaling within the Brain: Roles in Neurogenesis, Neuroprotection, and Sexual Behaviors. Front Neurosci 2018; 12:84. [PMID: 29515356 PMCID: PMC5826223 DOI: 10.3389/fnins.2018.00084] [Citation(s) in RCA: 97] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Accepted: 02/02/2018] [Indexed: 01/18/2023] Open
Abstract
Sex steroid hormones are synthesized from cholesterol and exert pleiotropic effects notably in the central nervous system. Pioneering studies from Baulieu and colleagues have suggested that steroids are also locally-synthesized in the brain. Such steroids, called neurosteroids, can rapidly modulate neuronal excitability and functions, brain plasticity, and behavior. Accumulating data obtained on a wide variety of species demonstrate that neurosteroidogenesis is an evolutionary conserved feature across fish, birds, and mammals. In this review, we will first document neurosteroidogenesis and steroid signaling for estrogens, progestagens, and androgens in the brain of teleost fish, birds, and mammals. We will next consider the effects of sex steroids in homeostatic and regenerative neurogenesis, in neuroprotection, and in sexual behaviors. In a last part, we will discuss the transport of steroids and lipoproteins from the periphery within the brain (and vice-versa) and document their effects on the blood-brain barrier (BBB) permeability and on neuroprotection. We will emphasize the potential interaction between lipoproteins and sex steroids, addressing the beneficial effects of steroids and lipoproteins, particularly HDL-cholesterol, against the breakdown of the BBB reported to occur during brain ischemic stroke. We will consequently highlight the potential anti-inflammatory, anti-oxidant, and neuroprotective properties of sex steroid and lipoproteins, these latest improving cholesterol and steroid ester transport within the brain after insults.
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Affiliation(s)
- Nicolas Diotel
- Université de La Réunion, Institut National de la Santé et de la Recherche Médicale, UMR 1188, Diabète athérothrombose Thérapies Réunion Océan Indien, Saint-Denis de La Réunion, France
| | - Thierry D. Charlier
- Univ Rennes, Inserm, EHESP, Irset (Institut de recherche en santé, environnement et travail) - UMR_S 1085, Rennes, France
| | - Christian Lefebvre d'Hellencourt
- Université de La Réunion, Institut National de la Santé et de la Recherche Médicale, UMR 1188, Diabète athérothrombose Thérapies Réunion Océan Indien, Saint-Denis de La Réunion, France
| | - David Couret
- Université de La Réunion, Institut National de la Santé et de la Recherche Médicale, UMR 1188, Diabète athérothrombose Thérapies Réunion Océan Indien, Saint-Denis de La Réunion, France
- CHU de La Réunion, Saint-Denis, France
| | | | - Joel C. Nicolau
- Univ Rennes, Inserm, EHESP, Irset (Institut de recherche en santé, environnement et travail) - UMR_S 1085, Rennes, France
| | - Olivier Meilhac
- Université de La Réunion, Institut National de la Santé et de la Recherche Médicale, UMR 1188, Diabète athérothrombose Thérapies Réunion Océan Indien, Saint-Denis de La Réunion, France
- CHU de La Réunion, Saint-Denis, France
| | - Olivier Kah
- Univ Rennes, Inserm, EHESP, Irset (Institut de recherche en santé, environnement et travail) - UMR_S 1085, Rennes, France
| | - Elisabeth Pellegrini
- Univ Rennes, Inserm, EHESP, Irset (Institut de recherche en santé, environnement et travail) - UMR_S 1085, Rennes, France
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37
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Impact of aromatase absence on murine intraocular pressure and retinal ganglion cells. Sci Rep 2018; 8:3280. [PMID: 29459742 PMCID: PMC5818491 DOI: 10.1038/s41598-018-21475-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Accepted: 01/31/2018] [Indexed: 12/14/2022] Open
Abstract
We hypothesize that aromatase, an enzyme that regulates estrogen production, plays a significant role in the control of intraocular pressure (IOP) and retinal ganglion cells (RGCs). To begin to test our hypothesis, we examined the impact of aromatase absence, which completely eliminates estrogen synthesis, in male and female mice. Studies were performed with adult, age-matched wild type (WT) and aromatase knockout (ArKO) mice. IOP was measured in a masked fashion in both eyes of conscious mice at 12 and 24 weeks of age. Retinas were obtained and processed for RGC counting with a confocal microscope. IOP levels in both 12- and 24-week old female ArKO mice were significantly higher than those of age- and sex-matched WT controls. The mean increase in IOP was 7.9% in the 12-week-, and 19.7% in the 24-week-old mice, respectively. These changes were accompanied by significant 9% and 7% decreases in RGC numbers in the ArKO female mice, relative to controls, at 12- and 24-weeks, respectively. In contrast, aromatase deficiency did not lead to an increased IOP in male mice. There was a significant reduction in RGC counts in the 12-, but not 24-, week-old male ArKO mice, as compared to their age- and sex-matched WT controls. Overall, our findings show that aromatase inhibition in females is associated with elevated IOP and reduced RGC counts.
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38
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Hojo Y, Kawato S. Neurosteroids in Adult Hippocampus of Male and Female Rodents: Biosynthesis and Actions of Sex Steroids. Front Endocrinol (Lausanne) 2018; 9:183. [PMID: 29740398 PMCID: PMC5925962 DOI: 10.3389/fendo.2018.00183] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Accepted: 04/04/2018] [Indexed: 12/13/2022] Open
Abstract
The brain is not only the target of steroid hormones but also is able to locally synthesize steroids de novo. Evidence of the local production of steroids in the brain has been accumulating in various vertebrates, including teleost fish, amphibia, birds, rodents, non-human primates, and humans. In this review, we mainly focus on the local production of sex steroids in the hippocampal neurons of adult rodents (rats and mice), a center for learning and memory. From the data of the hippocampus of adult male rats, hippocampal principal neurons [pyramidal cells in CA1-CA3 and granule cells in dentate gyrus (DG)] have a complete system for biosynthesis of sex steroids. Liquid chromatography with tandem-mass-spectrometry (LC-MS/MS) enabled us to accurately determine the levels of hippocampal sex steroids including 17β-estradiol (17β-E2), testosterone (T), and dihydrotestosterone (DHT), which are much higher than those in blood. Next, we review the steroid synthesis in the hippocampus of female rats, since previous knowledge had been biased toward the data from males. Recently, we clarified that the levels of hippocampal steroids fluctuate in adult female rats across the estrous cycle. Accurate determination of hippocampal steroids at each stage of the estrous cycle is of importance for providing the account for the fluctuation of female hippocampal functions, including spine density, long-term potentiation (LTP) and long-term depression (LTD), and learning and memory. These functional fluctuations in female had been attributed to the level of circulation-derived steroids. LC-MS/MS analysis revealed that the dendritic spine density in CA1 of adult female hippocampus correlates with the levels of hippocampal progesterone and 17β-E2. Finally, we introduce the direct evidence of the role of hippocampus-synthesized steroids in hippocampal function including neurogenesis, LTP, and memory consolidation. Mild exercise (2 week of treadmill running) elevated synthesis of DHT in the hippocampus, but not in the testis, of male rats, resulting in enhancement of neurogenesis in DG. Concerning synaptic plasticity, hippocampus-synthesized E2 is required for LTP induction, whereas hippocampus-synthesized DHT is required for LTD induction. Furthermore, hippocampus-synthesized E2 is involved in memory consolidation tested by object recognition and object placement tasks, both of which are hippocampus-dependent.
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Affiliation(s)
- Yasushi Hojo
- Department of Biochemistry, Faculty of Medicine, Saitama Medical University, Moroyama, Saitama, Japan
- *Correspondence: Yasushi Hojo,
| | - Suguru Kawato
- Department of Biophysics and Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan
- Department of Urology, Graduate School of Medicine, Juntendo University, Tokyo, Japan
- Department of Cognitive Neuroscience, Faculty of Pharma-Science, Teikyo University, Tokyo, Japan
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39
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Scharfman HE, MacLusky NJ. Sex differences in hippocampal area CA3 pyramidal cells. J Neurosci Res 2017; 95:563-575. [PMID: 27870399 DOI: 10.1002/jnr.23927] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2016] [Revised: 08/14/2016] [Accepted: 08/24/2016] [Indexed: 11/07/2022]
Abstract
Numerous studies have demonstrated differences between males and females in hippocampal structure, function, and plasticity. There also are many studies about the different predisposition of a males and females for disorders where the hippocampus plays an important role. Many of these reports focus on area CA1, but other subfields are also very important, and unlikely to be the same as area CA1 based on what is known. Here we review basic studies of male and female structure, function, and plasticity of area CA3 pyramidal cells of adult rats. The data suggest that the CA3 pyramidal cells of males and females are distinct in structure, function, and plasticity. These sex differences cannot be simply explained by the effects of circulating gonadal hormones. This view agrees with previous studies showing that there are substantial sex differences in the brain that cannot be normalized by removing the gonads and depleting peripheral gonadal hormones. Implications of these comparisons for understanding sex differences in hippocampal function and dysfunction are discussed. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Helen E Scharfman
- Department of Child and Adolescent Psychiatry, Physiology and Neuroscience, and Psychiatry, New York University Langone Medical Center, New York, New York.,Department of Nathan S. Kline Institute for Psychiatric Research, Orangeburg, New York
| | - Neil J MacLusky
- Department of Biomedical Sciences, University of Guelph, Guelph, Ontario, Canada
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40
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Dachtler J, Fox K. Do cortical plasticity mechanisms differ between males and females? J Neurosci Res 2017; 95:518-526. [PMID: 27870449 PMCID: PMC5111614 DOI: 10.1002/jnr.23850] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Revised: 06/20/2016] [Accepted: 07/06/2016] [Indexed: 12/24/2022]
Abstract
The difference between male and female behavior and male and female susceptibility to a number of neuropsychiatric conditions is not controversial. From a biological perspective, one might expect to see at least some of these differences underpinned by identifiable physical differences in the brain. This Mini‐Review focuses on evidence that plasticity mechanisms differ between males and females and ask at what scale of organization the differences might exist, at the systems level, the circuits level, or the synaptic level. Emerging evidence suggests that plasticity differences may extend to the scale of synaptic mechanisms. In particular, the CaMKK, NOS1 and estrogen receptor pathways show sexual dimorphisms with implications for plasticity in the hippocampus and cerebral cortex. © 2016 The Authors. Journal of Neuroscience Research Published by Wiley Periodicals, Inc.
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Affiliation(s)
- James Dachtler
- Department of Psychology, Durham University, Durham, United Kingdom
| | - Kevin Fox
- School of Biosciences, Cardiff University, Cardiff, United Kingdom
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41
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Bao J, Mahaman YAR, Liu R, Wang JZ, Zhang Z, Zhang B, Wang X. Sex Differences in the Cognitive and Hippocampal Effects of Streptozotocin in an Animal Model of Sporadic AD. Front Aging Neurosci 2017; 9:347. [PMID: 29163130 PMCID: PMC5671606 DOI: 10.3389/fnagi.2017.00347] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 10/16/2017] [Indexed: 01/07/2023] Open
Abstract
More than 95% of Alzheimer's disease (AD) belongs to sporadic AD (sAD), and related animal models are the important research tools for investigating the pathogenesis and developing new drugs for sAD. An intracerebroventricular infusion of streptozotocin (ICV-STZ) is commonly employed to generate sporadic AD animal model. Moreover, the potential impact of sex on brain function is now emphasized in the field of AD. However, whether sex differences exist in AD animal models remains unknown. Here we reported that ICV-STZ remarkably resulted in learning and memory impairment in the Sprague-Dawley male rats, but not in the female rats. We also found tau hyperphosphorylation, an increase of Aβ40/42 as well as increase in both GSK-3β and BACE1 activities, while a loss of dendritic and synaptic plasticity was observed in the male STZ rats. However, STZ did not induce above alterations in the female rats. Furthermore, estradiol levels of serum and hippocampus of female rats were much higher than that of male rats. In conclusion, sex differences exist in this sporadic AD animal model (Sprague-Dawley rats induced by STZ), and this should be considered in future AD research.
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Affiliation(s)
- Jian Bao
- Key Laboratory of Ministry of Education of China for Neurological Disorders, Department of Pathophysiology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yacoubou A R Mahaman
- Key Laboratory of Ministry of Education of China for Neurological Disorders, Department of Pathophysiology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Rong Liu
- Key Laboratory of Ministry of Education of China for Neurological Disorders, Department of Pathophysiology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jian-Zhi Wang
- Key Laboratory of Ministry of Education of China for Neurological Disorders, Department of Pathophysiology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Zhiguo Zhang
- School of Medicine and Health Management, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Bin Zhang
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Xiaochuan Wang
- Key Laboratory of Ministry of Education of China for Neurological Disorders, Department of Pathophysiology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
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42
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Kim JI, Jeon SG, Kim KA, Kim JJ, Song EJ, Jeon Y, Kim E, Lee KB, Kwak JH, Moon M. Platycodon grandiflorus Root Extract Improves Learning and Memory by Enhancing Synaptogenesis in Mice Hippocampus. Nutrients 2017; 9:nu9070794. [PMID: 28737698 PMCID: PMC5537907 DOI: 10.3390/nu9070794] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 07/17/2017] [Accepted: 07/20/2017] [Indexed: 12/17/2022] Open
Abstract
Platycodon grandiflorus (Jacq.) A.DC. (PG) has long been used as an ingredient of foods and is known to have beneficial effects on cognitive functions as well. The present study examined the effect of each PG extract (PGE) from root, aerial part, and seeds on cognitive functions in mice. Changes in spatial learning and memory using a Y-maze test, and markers of adult hippocampal neurogenesis and synaptogenesis were examined. Moreover, changes in neuritogenesis and activation of the ERK1/2 pathway were investigated. Results indicated that mice administered PGE (root) showed increased spontaneous alternation in the Y-maze test and synaptogenesis in the hippocampus. In addition, PGE (root) and platycodin D, the major bioactive compound from the PG root, significantly stimulated neuritic outgrowth by phosphorylation of the ERK1/2 signaling pathway in vitro. These results indicate that the PGE (root), containing platycodin D, enhances cognitive function through synaptogenesis via activation of the ERK1/2 signaling pathway.
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Affiliation(s)
- Jin-Il Kim
- Department of Nursing, College of Nursing, Jeju National University, Jeju-si 63243, Korea.
| | - Seong Gak Jeon
- Department of Biochemistry, College of Medicine, Konyang University, Daejeon 35365, Korea.
| | - Kyoung Ah Kim
- Department of Biochemistry, College of Medicine, Konyang University, Daejeon 35365, Korea.
| | - Jwa-Jin Kim
- Department of Biomedical Science, Jungwon University, Goesan-gun, Chungbuk 28024, Korea.
- Department of Anatomy, School of Medicine, Chungnam National University, Daejeon 34134, Korea.
- LES Corporation Inc., 4 Munhwawon-ro 46beon-gil Yuseong-gu, Daejeon 34167, Korea.
| | - Eun Ji Song
- Department of Biochemistry, College of Medicine, Konyang University, Daejeon 35365, Korea.
| | - Yukyoung Jeon
- School of Pharmacy, Sungkyunkwan University, Suwon-si, Gyeonggi-do 16419, Korea.
| | - Eunbin Kim
- School of Pharmacy, Sungkyunkwan University, Suwon-si, Gyeonggi-do 16419, Korea.
| | - Kyung Bok Lee
- Department of Biochemistry, College of Medicine, Konyang University, Daejeon 35365, Korea.
| | - Jong Hwan Kwak
- School of Pharmacy, Sungkyunkwan University, Suwon-si, Gyeonggi-do 16419, Korea.
| | - Minho Moon
- Department of Biochemistry, College of Medicine, Konyang University, Daejeon 35365, Korea.
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43
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Bravo Durán DA, Silva Gómez AB, Gutiérrez Rosas AC, Trujillo A. Hemi-ovariectomies promote a decrease in the dendritic lengths of CA1 and CA3 neurons: A dimorphic effect of the cerebral hemispheres. Brain Res 2017; 1662:102-109. [PMID: 28267433 DOI: 10.1016/j.brainres.2017.03.001] [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: 10/01/2016] [Revised: 02/24/2017] [Accepted: 03/01/2017] [Indexed: 11/17/2022]
Abstract
Certain structures of the central nervous system (CNS) are morphologically and functionally related to the ovaries. Ovariectomy has been used to study the functional role of the ovaries in the CNS, as well as the role of the CNS on the reproductive system. In the present study, the effects of left and right hemi-ovariectomy on the morphology of pyramidal neurons from the CA1 and CA3 regions of the ventral hippocampus were studied. During the estrus phase, female Long-Evans rats underwent either left and right hemi-ovariectomies or left and right sham surgeries. Three estrous cycles later, the animals were sacrificed, and their brains were processed in Golgi-Cox stain and analyzed by the Sholl method to calculate the dendritic length of the CA1 and CA3 neurons of the left and right hemispheres. The results indicate that the dendritic lengths of the basilar and apical arbors of the CA1 neurons from the left hemisphere were shorter after both left and right hemi-ovariectomy, while the CA1 neurons from the right hemisphere were not affected by either procedure. However, the basilar dendritic arbors of the CA3 neurons from both hemispheres were affected by right hemi-ovariectomy. The spine density only decreased in the apical arbors in the CA3 neurons from the left hemisphere of rats that underwent right hemi-ovariectomy. This study's results indicate that hemi-ovariectomy in adult rats changes in the morphology of the CA1 and CA3 pyramidal neurons in the ventral hippocampus and that there are dimorphic responses between the hemispheres.
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Affiliation(s)
- Dolores Adriana Bravo Durán
- Laboratorio de Neurofisiología Experimental, Escuela de Biología, Universidad Autónoma de Puebla, Edificio 112A, Ciudad Universitaria, CP 72520 Puebla, Puebla, Mexico
| | - Adriana Berenice Silva Gómez
- Laboratorio de Neurofisiología Experimental, Escuela de Biología, Universidad Autónoma de Puebla, Edificio 112A, Ciudad Universitaria, CP 72520 Puebla, Puebla, Mexico.
| | - Ana Coral Gutiérrez Rosas
- Laboratorio de Neurofisiología Experimental, Escuela de Biología, Universidad Autónoma de Puebla, Edificio 112A, Ciudad Universitaria, CP 72520 Puebla, Puebla, Mexico
| | - Angélica Trujillo
- Laboratorio de Neuroendocrinología, Escuela de Biología, Universidad Autónoma de Puebla, Edificio 112A, Ciudad Universitaria, CP 72520 Puebla, Puebla, Mexico
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44
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Bundy JL, Vied C, Nowakowski RS. Sex differences in the molecular signature of the developing mouse hippocampus. BMC Genomics 2017; 18:237. [PMID: 28302071 PMCID: PMC5356301 DOI: 10.1186/s12864-017-3608-7] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 03/04/2017] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND A variety of neurological disorders, including Alzheimer's disease, Parkinson's disease, major depressive disorder, dyslexia and autism, are differentially prevalent between females and males. To better understand the possible molecular basis for the sex-biased nature of neurological disorders, we used a developmental series of female and male mice at 1, 2, and 4 months of age to assess both mRNA and protein in the hippocampus with RNA-sequencing and mass-spectrometry, respectively. RESULTS The transcriptomic analysis identifies 2699 genes that are differentially expressed between animals of different ages. The bulk of these differentially expressed genes are changed in both sexes at one or more ages, but a total of 198 transcripts are differentially expressed between females and males at one or more ages. The number of transcripts that are differentially expressed between females and males is greater in adult animals than in younger animals. Additionally, we identify 69 transcripts that show complex and sex-specific patterns of temporal regulation through postnatal development, 8 of which are heat-shock proteins. We also find a modest correlation between levels of mRNA and protein in the mouse hippocampus (Rho = 0.53). CONCLUSION This study adds to the substantial body of evidence for transcriptomic regulation in the hippocampus during postnatal development. Additionally, this analysis reveals sex differences in the transcriptome of the developing mouse hippocampus, and further clarifies the need to include both female and male mice in longitudinal studies involving molecular changes in the hippocampus.
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Affiliation(s)
- Joseph L Bundy
- Department of Biomedical Sciences, Florida State University College of Medicine, 1115 West Call Street, Tallahassee, FL, 32306, USA
| | - Cynthia Vied
- Department of Biomedical Sciences, Florida State University College of Medicine, 1115 West Call Street, Tallahassee, FL, 32306, USA.,Translational Science Laboratory, Florida State University College of Medicine, 1115 West Call Street, Tallahassee, FL, 32306, USA
| | - Richard S Nowakowski
- Department of Biomedical Sciences, Florida State University College of Medicine, 1115 West Call Street, Tallahassee, FL, 32306, USA.
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45
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Arbo BD, Vieira-Marques C, Ruiz-Palmero I, Ortiz-Rodriguez A, Arevalo MA, Garcia-Segura LM, Ribeiro MF. 4'-Chlorodiazepam modulates the development of primary hippocampal neurons in a sex-dependent manner. Neurosci Lett 2016; 639:98-102. [PMID: 28041963 DOI: 10.1016/j.neulet.2016.12.067] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 12/16/2016] [Accepted: 12/27/2016] [Indexed: 12/12/2022]
Abstract
The translocator protein 18kDa (TSPO) is located in the outer mitochondrial membrane and is involved in the cholesterol transport into the mitochondria and in the regulation of steroidogenesis and other mitochondrial functions. It is known that steroid hormones, such as estradiol, testosterone and dihydrotestosterone are neuroprotective and regulate neuritogenesis in the CNS by different mechanisms. However, the developmental effects of TSPO ligands in the CNS are not known. Therefore, the aim of this study was to identify the developmental effects of 4'-chlorodiazepam (4'-CD), a TSPO ligand, in primary cultures of male and female mouse hippocampal neurons. We observed that female neurons showed an advanced neuritogenesis compared to male neurons after 2days in vitro. Moreover, it was shown that 4'-CD administration accelerated the maturation of male hippocampal neurons, without changing the development of female neurons. These findings, showing that 4'-CD modulates the development of hippocampal neurons in a sex-dependent manner, suggest that TSPO may be involved in the regulation of neuritogenesis.
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Affiliation(s)
- B D Arbo
- Laboratório de Interação Neuro-Humoral, Department of Physiology, ICBS - Universidade Federal do Rio Grande do Sul (UFRGS), Rua Sarmento Leite, 500 (90050-170), Porto Alegre, RS, Brazil; Instituto Cajal, CSIC, Avenida Doctor Arce, 37 (28002), Madrid, Spain.
| | - C Vieira-Marques
- Laboratório de Interação Neuro-Humoral, Department of Physiology, ICBS - Universidade Federal do Rio Grande do Sul (UFRGS), Rua Sarmento Leite, 500 (90050-170), Porto Alegre, RS, Brazil; Instituto Cajal, CSIC, Avenida Doctor Arce, 37 (28002), Madrid, Spain
| | - I Ruiz-Palmero
- Instituto Cajal, CSIC, Avenida Doctor Arce, 37 (28002), Madrid, Spain
| | - A Ortiz-Rodriguez
- Instituto Cajal, CSIC, Avenida Doctor Arce, 37 (28002), Madrid, Spain
| | - M A Arevalo
- Instituto Cajal, CSIC, Avenida Doctor Arce, 37 (28002), Madrid, Spain
| | - L M Garcia-Segura
- Instituto Cajal, CSIC, Avenida Doctor Arce, 37 (28002), Madrid, Spain
| | - M F Ribeiro
- Laboratório de Interação Neuro-Humoral, Department of Physiology, ICBS - Universidade Federal do Rio Grande do Sul (UFRGS), Rua Sarmento Leite, 500 (90050-170), Porto Alegre, RS, Brazil
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46
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Circulating Estradiol Regulates Brain-Derived Estradiol via Actions at GnRH Receptors to Impact Memory in Ovariectomized Rats. eNeuro 2016; 3:eN-NWR-0321-16. [PMID: 28032117 PMCID: PMC5172373 DOI: 10.1523/eneuro.0321-16.2016] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2016] [Accepted: 11/14/2016] [Indexed: 01/09/2023] Open
Abstract
Systemic estradiol treatment enhances hippocampus-dependent memory in ovariectomized rats. Although these enhancements are traditionally thought to be due to circulating estradiol, recent data suggest these changes are brought on by hippocampus-derived estradiol, the synthesis of which depends on gonadotropin-releasing hormone (GnRH) activity. The goal of the current work is to test the hypothesis that peripheral estradiol affects hippocampus-dependent memory through brain-derived estradiol regulated via hippocampal GnRH receptor activity. In the first experiment, intracerebroventricular infusion of letrozole, which prevents the synthesis of estradiol, blocked the ability of peripheral estradiol administration in ovariectomized rats to enhance hippocampus-dependent memory in a radial-maze task. In the second experiment, hippocampal infusion of antide, a long-lasting GnRH receptor antagonist, blocked the ability of peripheral estradiol administration in ovariectomized rats to enhance hippocampus-dependent memory. In the third experiment, hippocampal infusion of GnRH enhanced hippocampus-dependent memory, the effects of which were blocked by letrozole infusion. Results indicate that peripheral estradiol-induced enhancement of cognition is mediated by brain-derived estradiol via hippocampal GnRH receptor activity.
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47
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Koss WA, Frick KM. Sex differences in hippocampal function. J Neurosci Res 2016; 95:539-562. [DOI: 10.1002/jnr.23864] [Citation(s) in RCA: 99] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Revised: 06/28/2016] [Accepted: 07/11/2016] [Indexed: 12/25/2022]
Affiliation(s)
- Wendy A. Koss
- Department of Psychology; University of Wisconsin-Milwaukee; Milwaukee Wisconsin
| | - Karyn M. Frick
- Department of Psychology; University of Wisconsin-Milwaukee; Milwaukee Wisconsin
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48
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Tuscher JJ, Szinte JS, Starrett JR, Krentzel AA, Fortress AM, Remage-Healey L, Frick KM. Inhibition of local estrogen synthesis in the hippocampus impairs hippocampal memory consolidation in ovariectomized female mice. Horm Behav 2016; 83:60-67. [PMID: 27178577 PMCID: PMC4915975 DOI: 10.1016/j.yhbeh.2016.05.001] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Accepted: 05/02/2016] [Indexed: 01/29/2023]
Abstract
The potent estrogen 17β-Estradiol (E2) plays a critical role in mediating hippocampal function, yet the precise mechanisms through which E2 enhances hippocampal memory remain unclear. In young adult female rodents, the beneficial effects of E2 on memory are generally attributed to ovarian-synthesized E2. However, E2 is also synthesized in the adult brain in numerous species, where it regulates synaptic plasticity and is synthesized in response to experiences such as exposure to females or conspecific song. Although de novo E2 synthesis has been demonstrated in rodent hippocampal cultures, little is known about the functional role of local E2 synthesis in mediating hippocampal memory function. Therefore, the present study examined the role of hippocampal E2 synthesis in hippocampal memory consolidation. Using bilateral dorsal hippocampal infusions of the aromatase inhibitor letrozole, we first found that blockade of dorsal hippocampal E2 synthesis impaired hippocampal memory consolidation. We next found that elevated levels of E2 in the dorsal hippocampus observed 30min after object training were blocked by dorsal hippocampal infusion of letrozole, suggesting that behavioral experience increases acute and local E2 synthesis. Finally, aromatase inhibition did not prevent exogenous E2 from enhancing hippocampal memory consolidation, indicating that hippocampal E2 synthesis is not necessary for exogenous E2 to enhance hippocampal memory. Combined, these data are consistent with the hypothesis that hippocampally-synthesized E2 is necessary for hippocampus-dependent memory consolidation in rodents.
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Affiliation(s)
- Jennifer J Tuscher
- Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, United States
| | - Julia S Szinte
- Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, United States
| | - Joseph R Starrett
- Department of Psychological and Brain Sciences and Neuroscience and Behavior Program, Center for Neuroendocrine Studies, University of Massachusetts Amherst, Amherst, MA, United States
| | - Amanda A Krentzel
- Department of Psychological and Brain Sciences and Neuroscience and Behavior Program, Center for Neuroendocrine Studies, University of Massachusetts Amherst, Amherst, MA, United States
| | - Ashley M Fortress
- Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, United States
| | - Luke Remage-Healey
- Department of Psychological and Brain Sciences and Neuroscience and Behavior Program, Center for Neuroendocrine Studies, University of Massachusetts Amherst, Amherst, MA, United States
| | - Karyn M Frick
- Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, United States.
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49
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Hamson DK, Roes MM, Galea LAM. Sex Hormones and Cognition: Neuroendocrine Influences on Memory and Learning. Compr Physiol 2016; 6:1295-337. [DOI: 10.1002/cphy.c150031] [Citation(s) in RCA: 118] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Fester L, Brandt N, Windhorst S, Pröls F, Bläute C, Rune GM. Control of aromatase in hippocampal neurons. J Steroid Biochem Mol Biol 2016; 160:9-14. [PMID: 26472556 DOI: 10.1016/j.jsbmb.2015.10.009] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Revised: 10/01/2015] [Accepted: 10/08/2015] [Indexed: 10/22/2022]
Abstract
Our knowledge on estradiol-induced modulation of synaptic function in the hippocampus is widely based on results following the application of the steroid hormone to either cell cultures, or after the treatment of gonadectomized animals, thus ignoring local neuronal estrogen synthesis. We and others, however, have shown that hippocampus-derived estradiol also controls synaptic plasticity in the hippocampus. Estradiol synthesis in the hippocampus is regulated by several mechanisms, which are reviewed in this report. The regulation of the activity of aromatase, the final enzyme of estrogen biosynthesis, by Ca(2+) transients, is of particular interest. Aromatase becomes inactivated as soon as it is phosphorylated by Ca(2+)-dependent kinases upon calcium release from internal stores. Accordingly, thapsigargin dephosphorylates aromatase and stimulates estradiol synthesis by depletion of internal Ca(2+) stores. Vice versa, letrozole, an aromatase inhibitor, phosphorylates aromatase and reduces estradiol synthesis. Treatment of the cultures with 17β-estradiol results in phosphorylation of the enzyme and increased aromatase protein expression, which suggests that estradiol synthesis in hippocampal neurons is regulated in an autocrine manner.
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Affiliation(s)
- Lars Fester
- University Medical Center Hamburg Eppendorf, Institute of Neuroanatomy, Martinistr. 52, 20246 Hamburg, Germany
| | - Nicola Brandt
- University Medical Center Hamburg Eppendorf, Institute of Neuroanatomy, Martinistr. 52, 20246 Hamburg, Germany
| | - Sabine Windhorst
- Department of Biochemistry and Signal Transduction, Martinistr. 52, 20246 Hamburg, Germany
| | - Felicitas Pröls
- University Medical Center Hamburg Eppendorf, Institute of Neuroanatomy, Martinistr. 52, 20246 Hamburg, Germany
| | - Corinna Bläute
- University Medical Center Hamburg Eppendorf, Institute of Neuroanatomy, Martinistr. 52, 20246 Hamburg, Germany
| | - Gabriele M Rune
- University Medical Center Hamburg Eppendorf, Institute of Neuroanatomy, Martinistr. 52, 20246 Hamburg, Germany.
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