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Abstract
Regenerative therapeutics hold the promise of self-renewal and repair. Ageing and age-associated neurodegenerative diseases are marked by a decline in self-renewal and repair, but a capacity for regeneration is retained. The challenge faced by researchers developing molecular therapeutics to promote self-renewal in the nervous system is to activate regenerative and repair pathways often in the context of progressive degeneration. Neurosteroids regulate both regeneration and repair systems in the brain, and among this class of molecules, allopregnanolone has been broadly investigated for its role to promote regeneration in both the central and peripheral nervous systems. In the brain, allopregnanolone induced generation and survival of new neurons in the hippocampus of both aged mice and mice with Alzheimer disease, accompanied by restoration of associative learning and memory function. In the brain of mice with Alzheimer disease, allopregnanolone increased liver X receptor and pregnane X receptor expression, reduced amyloid-β and microglial activation, and increased markers of myelin and white matter generation. Therapeutic windows for efficacy of allopregnanolone were evident in the brains of mice with both normal ageing and Alzheimer disease. Allopregnanolone dose and a regenerative treatment regimen of intermittent allopregnanolone exposure were determining factors regulating therapeutic efficacy. Allopregnanolone serves as proof of concept for therapeutics that target endogenous regeneration, windows of therapeutic opportunity for regeneration, and critical system biology factors that will determine the efficacy of regeneration.
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Affiliation(s)
- Roberta D Brinton
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 90033, USA.
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152
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Marin SE, Mesterman R, Robinson B, Rodenburg RJ, Smeitink J, Tarnopolsky MA. Leigh syndrome associated with mitochondrial complex I deficiency due to novel mutations In NDUFV1 and NDUFS2. Gene 2013; 516:162-7. [DOI: 10.1016/j.gene.2012.12.024] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Revised: 10/08/2012] [Accepted: 12/02/2012] [Indexed: 11/28/2022]
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153
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Yao J, Zhao L, Mao Z, Chen S, Wong KC, To J, Brinton RD. Potentiation of brain mitochondrial function by S-equol and R/S-equol estrogen receptor β-selective phytoSERM treatments. Brain Res 2013; 1514:128-41. [PMID: 23428542 DOI: 10.1016/j.brainres.2013.02.021] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Revised: 01/26/2013] [Accepted: 02/09/2013] [Indexed: 12/23/2022]
Abstract
Previously we developed an estrogen receptor β-selective phytoestrogenic (phytoSERM) combination, which contains a mixture of genistein, daidzein, and racemic R/S-equol. The phytoSERM combination was found neuroprotective and non-feminizing both in vitro and in vivo. Further, it prevented or alleviated physical and neurological changes associated with human menopause and Alzheimer's disease. In the current study, we conducted translational analyses to compare the effects of racemic R/S-equol-containing with S-equol-containing phytoSERM therapeutic combinations on mitochondrial markers in rat hippocampal neuronal cultures and in a female mouse ovariectomy (OVX) model. Data revealed that both the S-equol and R/S-equol phytoSERM treatments regulated mitochondrial function, with S-equol phytoSERM combination eliciting greater response in mitochondrial potentiation. Both phytoSERM combination treatments increased expression of key proteins and enzymes involved in energy production, restored the OVX-induced decrease in activity of key bioenergetic enzymes, and reduced OVX-induced increase in lipid peroxidation. Comparative analyses on gene expression profile revealed similar regulation between S-equol phytoSERM and R/S-equol phytoSERM treatments with minimal differences. Both combinations regulated genes involved in essential bioenergetic pathways, including glucose metabolism and energy sensing, lipid metabolism, cholesterol trafficking, redox homeostasis and β-amyloid production and clearance. Further, no uterotrophic response was induced by either of the phytoSERM combinations. These findings indicate translational validity for development of an ER β selective S-equol phytoSERM combination as a nutraceutical to prevent menopause-associated symptoms and to promote brain metabolic activity. This article is part of a Special Issue entitled Hormone Therapy.
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Affiliation(s)
- Jia Yao
- University of Southern California, Pharmacology and Pharmaceutical Sciences, School of Pharmacy, 1985 Zonal Avenue, PSC-502, Los Angeles, CA 90033, United States
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154
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Raval AP, Borges-Garcia R, Diaz F, Sick TJ, Bramlett H. Oral contraceptives and nicotine synergistically exacerbate cerebral ischemic injury in the female brain. Transl Stroke Res 2013; 4:402-12. [PMID: 24323338 DOI: 10.1007/s12975-013-0253-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Revised: 01/24/2013] [Accepted: 01/28/2013] [Indexed: 02/06/2023]
Abstract
Oral contraceptives (OC) and smoking-derived nicotine (N) are known to synergistically increase the risk and severity of cerebral ischemia in women. Although it has been known for some time that long-term use of OC and nicotine will have an increased risk of peripheral thrombus formation, little is known about how the combination of OC and nicotine increases severity of brain ischemia. Recent laboratory studies simulating the conditions of nicotine exposure produced by cigarette smoking and OC regimen of women in female rats confirms that the severity of ischemic hippocampal damage is far greater in female rats simultaneously exposed to OC than to nicotine alone. These studies also demonstrated that the concurrent exposure of OC and nicotine reduces endogenous 17β-estradiol levels and inhibits estrogen signaling in the brain of female rats. The endogenous 17β-estradiol plays a key role in cerebrovascular protection in women during their pre-menopausal life and loss of circulating estrogen at reproductive senescence increases both the incidence and severity of cerebrovascular diseases. Therefore, OC and nicotine induced severe post-ischemic damage might be a consequence of lack of estrogen signaling in the brain. In the present review we highlight possible mechanisms by which OC and nicotine inhibits estrogen signaling that could be responsible for severe ischemic damage in females.
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Affiliation(s)
- Ami P Raval
- Cerebral Vascular Disease Research Center, Department of Neurology, Leonard M. Miller School of Medicine, University of Miami, Two Story Lab (TSL), Room # 230A, 1420 NW 9th Avenue, Miami, FL, 33101, USA,
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155
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Diotel N, Vaillant C, Gabbero C, Mironov S, Fostier A, Gueguen MM, Anglade I, Kah O, Pellegrini E. Effects of estradiol in adult neurogenesis and brain repair in zebrafish. Horm Behav 2013; 63:193-207. [PMID: 22521210 DOI: 10.1016/j.yhbeh.2012.04.003] [Citation(s) in RCA: 118] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2011] [Revised: 04/03/2012] [Accepted: 04/04/2012] [Indexed: 12/21/2022]
Abstract
The brain of the adult teleost fish exhibits intense neurogenic activity and an outstanding capability for brain repair. Remarkably, the brain estrogen-synthesizing enzyme, aromatase B, is strongly expressed, particularly in adult fishes, in radial glial cells, which act as progenitors. Using zebrafish, we tested the hypothesis that estrogens affect adult neurogenesis and brain regeneration by modulating the neurogenic activity of radial glial cells. To investigate this, the estrogenic environment was modified through inhibition of aromatase activity, blockade of nuclear estrogen receptors, or estrogenic treatments. Estrogens significantly decreased cell proliferation and migration at the olfactory bulbs/telencephalon junction and in the mediobasal hypothalamus. It also appears that cell survival is reduced at the olfactory bulbs/telencephalon junction. We also developed a model of telencephalic lesion to assess the role of aromatase and estrogens in brain repair. Proliferation increased rapidly immediately after the lesion in the parenchyma of the injured telencephalon, while proliferation at the ventricular surface appeared after 48 h and peaked at 7 days. At this time, most proliferative cells express Sox2, however, none of these Sox2 positive cells correspond to aromatase B-positive radial glial cells. Interestingly, aromatase B expression was significantly reduced 48 h and 7 days after the injury, but surprisingly, at 72 h after lesion, aromatase B expression appeared de novo expressed in parenchyma cells, suggesting a role for this ectopic expression of aromatase in brain repair mechanisms. Altogether these data suggest that estrogens modulate adult, but not reparative neurogenesis, in zebrafish.
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Affiliation(s)
- Nicolas Diotel
- Neuroendocrine Effects of Endocrine Disruptors, Inserm, IRSET, U1085, Université de Rennes 1, Rennes, France
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156
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Schmidt PJ, Keenan PA, Schenkel LA, Berlin K, Gibson C, Rubinow DR. Cognitive performance in healthy women during induced hypogonadism and ovarian steroid addback. Arch Womens Ment Health 2013; 16:47-58. [PMID: 23188540 PMCID: PMC3547128 DOI: 10.1007/s00737-012-0316-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Accepted: 10/23/2012] [Indexed: 01/15/2023]
Abstract
Gynecology clinic-based studies have consistently demonstrated that induced hypogonadism is accompanied by a decline in cognitive test performance. However, a recent study in healthy asymptomatic controls observed that neither induced hypogonadism nor estradiol replacement influenced cognitive performance. Thus, the effects of induced hypogonadism on cognition might not be uniformly experienced across individual women. Moreover, discrepancies in the effects of hypogonadism on cognition also could suggest the existence of specific risk phenotypes that predict a woman's symptomatic experience during menopause. In this study, we examined the effects of induced hypogonadism and ovarian steroid replacement on cognitive performance in healthy premenopausal women. Ovarian suppression was induced with a GnRH agonist (Lupron) and then physiologic levels of estradiol and progesterone were reintroduced in 23 women. Cognitive tests were administered during each hormone condition. To evaluate possible practice effects arising during repeated testing, an identical battery of tests was administered at the same time intervals in 11 untreated women. With the exception of an improved performance on mental rotation during estradiol, we observed no significant effects of estradiol or progesterone on measures of attention, concentration, or memory compared with hypogonadism. In contrast to studies in which a decline in cognitive performance was observed in women receiving ovarian suppression therapy for an underlying gynecologic condition, we confirm a prior report demonstrating that short-term changes in gonadal steroids have a limited effect on cognition in young, healthy women. Differences in the clinical characteristics of the women receiving GnRH agonists could predict a risk for ovarian steroid-related changes in cognitive performance during induced, and possibly, natural menopause.
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Affiliation(s)
- Peter J Schmidt
- Section on Behavioral Endocrinology, National Institute of Mental Health, National Institutes of Health, Department of Health & Human Services, Bethesda, MD 20892-1277, USA.
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157
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Cui J, Shen Y, Li R. Estrogen synthesis and signaling pathways during aging: from periphery to brain. Trends Mol Med 2013; 19:197-209. [PMID: 23348042 DOI: 10.1016/j.molmed.2012.12.007] [Citation(s) in RCA: 461] [Impact Index Per Article: 41.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2012] [Revised: 12/18/2012] [Accepted: 12/27/2012] [Indexed: 01/05/2023]
Abstract
Estrogens are the primary female sex hormones and play important roles in both reproductive and non-reproductive systems. Estrogens can be synthesized in non-reproductive tissues such as liver, heart, muscle, bone and brain, and tissue-specific estrogen synthesis is consistent with a diversity of estrogen actions. In this article we review tissue and cell-specific estrogen synthesis and estrogen receptor signaling in three parts: (i) synthesis and metabolism, (ii) the distribution of estrogen receptors and signaling, and (iii) estrogen functions and related disorders, including cardiovascular diseases, osteoporosis, Alzheimer's disease (AD), and Parkinson disease (PD). This comprehensive review provides new insights into estrogens by giving a better understanding of the tissue-specific estrogen effects and their roles in various diseases.
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Affiliation(s)
- Jie Cui
- Center for Hormone Advanced Science and Education (CHASE), Roskamp Institute, Sarasota, FL 34243, USA
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158
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Ishunina TA, Sluiter AA, Swaab DF, Verwer RWH. Transcriptional activity of human brain estrogen receptor-α splice variants: evidence for cell type-specific regulation. Brain Res 2013; 1500:1-9. [PMID: 23333800 DOI: 10.1016/j.brainres.2012.12.050] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Revised: 12/19/2012] [Accepted: 12/27/2012] [Indexed: 12/19/2022]
Abstract
Estrogen receptor α (ERα) isoforms with complex types of alternative splicing are naturally present in the human brain and may affect canonical receptor signaling. In the present study we investigated transcriptional activity of common ERα splice variants from this group with different molecular defects: MB1 (intron retention), TADDI (small deletion between exons 3 and 4 with an insert), the Δ (deletion) 3(⁎)-7(*)/819 (complete skipping of exons 4, 5 and 6 and partial deletion of exons 3 and 7) and the Δ3-6 (lacking exons 3, 4, 5 and 6) in HeLa and M17 cells upon stimulation with (17β)estradiol or insulin-like growth factor 1 (IGF-1). In HeLa cells, all these splice variants showed the dominant negative function that was more pronounced for the TADDI. In M17 cells the dominant negative variants appeared to be the MB1 and the Δ3-6, whereas TADDI turned out to be a clearly dominant positive variant. In M17 cells mRNA levels of Δ3-6 and Δ3(*)-7(*)/819 variants increased following (17β)estradiol administration. In Hela cells (17β)estradiol up-regulated the IGF-1 receptor mRNA levels in cultures transfected with MB1, TADDI and Δ3(*)-7(*)/819. Our data demonstrate that ERα splice variants show differential levels of the transcriptional activity in a cell type-specific way and that IGF-1 signaling pathways are differentially employed in a cell-type specific manner depending on the level of the discrete ERα splice variants expressed. Functional properties of various ERα splice variants and their cell type-specificity should, thus, be considered as potential confounders of estrogen therapy effects on the brain.
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Affiliation(s)
- T A Ishunina
- Netherlands Institute for Neuroscience, an Institute of the Royal Netherlands Academy of Arts and Sciences, Meibergdreef 47, 1105 BA Amsterdam, The Netherlands.
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159
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Estrogen enhances the retention of spatial reference memory in the open field tower task, but disrupts the expression of spatial memory following a novel start position. Neurobiol Learn Mem 2013. [DOI: 10.1016/j.nlm.2012.11.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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160
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Srivastava DP, Woolfrey KM, Evans PD. Mechanisms underlying the interactions between rapid estrogenic and BDNF control of synaptic connectivity. Neuroscience 2012; 239:17-33. [PMID: 23246844 DOI: 10.1016/j.neuroscience.2012.12.004] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Revised: 12/03/2012] [Accepted: 12/04/2012] [Indexed: 12/14/2022]
Abstract
The effects of the steroid hormone 17β-estradiol and the neurotrophin brain-derived neurotrophic factor (BDNF) on neuronal physiology have been well investigated. Numerous studies have demonstrated that each signal can exert powerful influences on the structure and function of synapses, and specifically on dendritic spines, both within short and long time frames. Moreover, it has been suggested that BDNF is required for the long-term, or genomic, actions of 17β-estradiol on dendritic spines, via its ability to regulate the expression of neurotrophins. Here we focus on the acute, or rapid effects, of 17β-estradiol and BDNF, and their ability to activate specific signalling cascades, resulting in alterations in dendritic spine morphology. We first review recent literature describing the mechanisms by which 17β-estradiol activates these pathways, and the resulting alterations in dendritic spine number. We then describe the molecular mechanisms underlying acute modulation of dendritic spine morphology by BDNF. Finally, we consider how this new evidence may suggest that the temporal interactions of 17β-estradiol and BDNF can occur more rapidly than previously reported. Building on these new data, we propose a novel model for the interactions of this steroid and neurotrophin, whereby rapid, non-genomic 17β-estradiol and acute BDNF signal in a co-operative manner, resulting in dendritic spine formation and subsequent stabilization in support of synapse and circuit plasticity. This extended hypothesis suggests an additional mechanism by which these two signals may modulate dendritic spines in a time-specific manner.
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Affiliation(s)
- D P Srivastava
- Department of Neuroscience & Centre for the Cellular Basis of Behaviour, The James Black Centre, Institute of Psychiatry, King's College London, London SE5 9NU, UK.
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161
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Kramár EA, Babayan AH, Gall CM, Lynch G. Estrogen promotes learning-related plasticity by modifying the synaptic cytoskeleton. Neuroscience 2012; 239:3-16. [PMID: 23103216 DOI: 10.1016/j.neuroscience.2012.10.038] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Revised: 10/11/2012] [Accepted: 10/18/2012] [Indexed: 01/04/2023]
Abstract
Estrogen's acute, facilitatory effects on glutamatergic transmission and long-term potentiation (LTP) provide a potential explanation for the steroid's considerable influence on behavior. Recent work has identified mechanisms underlying these synaptic actions. Brief infusion of 17ß-estradiol (E2) into adult male rat hippocampal slices triggers actin polymerization within dendritic spines via a signaling cascade beginning with the GTPase RhoA and ending with inactivation of the filament-severing protein cofilin. Blocking this sequence, or actin polymerization itself, eliminates E2's effects on synaptic physiology. Notably, the theta burst stimulation used to induce LTP activates the same signaling pathway as E2 plus events that stabilize the reorganization of the sub-synaptic cytoskeleton. These observations suggest that E2 elicits a partial form of LTP, resulting in an increase of fast excitatory postsynaptic potentials (EPSPs) and a reduction in the threshold for lasting synaptic changes. While E2's effects on the cytoskeleton could be direct, results described here indicate that the hormone activates synaptic tropomyosin-related kinase B (TrkB) receptors for brain-derived neurotrophic factor (BDNF), a releasable neurotrophin that stimulates the RhoA to cofilin pathway. It is therefore possible that E2 acts via transactivation of neighboring receptors to modify the composition and structure of excitatory contacts. Finally, there is the question of whether a loss of acute synaptic actions contributes to the memory problems associated with estrogen depletion. Initial tests found that ovariectomy in middle-aged rats disrupts RhoA signaling, actin polymerization, and LTP consolidation. Acute applications of E2 reversed these defects, a result consistent with the idea that disturbances to actin management are one cause of behavioral effects that emerge with reductions in steroid levels.
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Affiliation(s)
- E A Kramár
- Department of Anatomy and Neurobiology, University of California, Irvine, CA 92697, USA.
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162
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Jeng SR, Yueh WS, Pen YT, Gueguen MM, Pasquier J, Dufour S, Chang CF, Kah O. Expression of aromatase in radial glial cells in the brain of the Japanese eel provides insight into the evolution of the cyp191a gene in Actinopterygians. PLoS One 2012; 7:e44750. [PMID: 22957105 PMCID: PMC3434150 DOI: 10.1371/journal.pone.0044750] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Accepted: 08/06/2012] [Indexed: 11/23/2022] Open
Abstract
The cyp19a1 gene that encodes aromatase, the only enzyme permitting conversion of C19 aromatizable androgens into estrogens, is present as a single copy in the genome of most vertebrate species, except in teleosts in which it has been duplicated. This study aimed at investigating the brain expression of a cyp19a1 gene expressed in both gonad and brain of Japanese eel, a basal teleost. By means of immunohistochemistry and in situ hybridization, we show that cyp19a1 is expressed only in radial glial cells of the brain and in pituitary cells. Treatments with salmon pituitary homogenates (female) or human chorionic gonadotrophin (male), known to turn on steroid production in immature eels, strongly stimulated cyp19a1 messenger and protein expression in radial glial cells and pituitary cells. Using double staining studies, we also showed that aromatase-expressing radial glial cells exhibit proliferative activity in both the brain and the pituitary. Altogether, these data indicate that brain and pituitary expression of Japanese eel cyp19a1 exhibits characteristics similar to those reported for the brain specific cyp19a1b gene in teleosts having duplicated cyp19a1 genes. This supports the hypothesis that, despite the fact that eels also underwent the teleost specific genome duplication, they have a single cyp19a1 expressed in both brain and gonad. Such data also suggest that the intriguing features of brain aromatase expression in teleost fishes were not gained after the whole genome duplication and may reflect properties of the cyp19a1 gene of ancestral Actinopterygians.
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Affiliation(s)
- Shan-Ru Jeng
- Department of Aquaculture, National Kaohsiung Marine University, Kaohsiung, Taiwan
- Team NEED, Institut de Recherche en Santé, Environnement et Travail, INSERM U1085, IFR140, Université de Rennes 1, Rennes, France
| | - Wen-Shiun Yueh
- Department of Aquaculture, National Kaohsiung Marine University, Kaohsiung, Taiwan
| | - Yi-Ting Pen
- Department of Aquaculture, National Kaohsiung Marine University, Kaohsiung, Taiwan
| | - Marie-Madeleine Gueguen
- Team NEED, Institut de Recherche en Santé, Environnement et Travail, INSERM U1085, IFR140, Université de Rennes 1, Rennes, France
| | - Jérémy Pasquier
- Research Unit BOREA, Biology of Aquatic Organisms and Ecosystems, CNRS 7208/IRD 207/UPMC, Muséum National d'Histoire Naturelle, Paris, France
| | - Sylvie Dufour
- Research Unit BOREA, Biology of Aquatic Organisms and Ecosystems, CNRS 7208/IRD 207/UPMC, Muséum National d'Histoire Naturelle, Paris, France
| | - Ching-Fong Chang
- Research Unit BOREA, Biology of Aquatic Organisms and Ecosystems, CNRS 7208/IRD 207/UPMC, Muséum National d'Histoire Naturelle, Paris, France
- Department of Aquaculture, Center of Excellence for Marine Bioenvironment and Biotechnology, National Taiwan Ocean University, Keelung, Taiwan
| | - Olivier Kah
- Team NEED, Institut de Recherche en Santé, Environnement et Travail, INSERM U1085, IFR140, Université de Rennes 1, Rennes, France
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163
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Pompili A, Arnone B, Gasbarri A. Estrogens and memory in physiological and neuropathological conditions. Psychoneuroendocrinology 2012; 37:1379-96. [PMID: 22309827 DOI: 10.1016/j.psyneuen.2012.01.007] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2011] [Revised: 01/13/2012] [Accepted: 01/13/2012] [Indexed: 12/22/2022]
Abstract
Ovarian hormones can influence brain regions crucial to higher cognitive functions, such as learning and memory, acting at structural, cellular and functional levels, and modulating neurotransmitter systems. Among the main effects of estrogens, the protective role that they may play against the deterioration of cognitive functions occurring with normal aging is of essential importance. In fact, during the last century, there has been a 30 years increase in female life expectancy, from 50 to 83 years; however, the mean age of spontaneous menopause remains stable, 50-51 years, with variability related to race and ethnicity. Therefore, women are now spending a greater fraction of their lives in a hypoestrogenic state. Although many cognitive functions seem to be unaffected by normal aging, age-related impairments are particularly evident in tasks involving working memory (WM), whose deficits are a recognized feature of Alzheimer's disease (AD). Many studies conducted over the past two decades showed that the female gonadal hormone estradiol can influence performance of learning and memory tasks, both in animal and humans. There is a great deal of evidence, mostly from animal models, that estrogens can facilitate or enhance performance on WM tasks; therefore, it is very important to clarify their role on this type of memory. To this aim, in this review we briefly describe the most relevant neurobiological bases of estrogens, that can explain their effects on cognitive functioning, and then we summarize the results of works conducted in our laboratory, both on animals and humans, utilizing the menstrual/estrous cycle as a useful noninvasive model. Finally, we review the possible role of estrogens in neuropathological conditions, such as AD and schizophrenia.
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Affiliation(s)
- Assunta Pompili
- Department of Biomedical Sciences and Technologies, University of L'Aquila, L'Aquila, Italy.
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164
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Charitidi K, Meltser I, Canlon B. Estradiol treatment and hormonal fluctuations during the estrous cycle modulate the expression of estrogen receptors in the auditory system and the prepulse inhibition of acoustic startle response. Endocrinology 2012; 153:4412-21. [PMID: 22778224 DOI: 10.1210/en.2012-1416] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Estrogens' effects on hearing are documented across species, but the responsible molecular mechanisms remain unknown. The presence of estrogen receptors (ER) throughout the auditory system offers a potential pathway of direct estrogenic effects on auditory function, but little is known about how each ER's expression is regulated by the overall hormonal status of the body. In the present study, we determined the effects of ovariectomy and chronic 17β-estradiol treatment on mRNA and protein expression of ERα and ERβ in peripheral (cochlea) and central (inferior colliculus) auditory structures of mice, as well as on auditory-related behavior using the acoustic startle response (ASR), prepulse inhibition (PPI), and habituation of the startle response. 17β-Estradiol treatment down-regulated ERα but not ERβ and increased PPI and latency of the ASR. Neither the magnitude nor the habituation of ASR was affected. Furthermore, ER's mRNA and protein expression in the inner ear were analyzed throughout the estrous cycle (proestrus, estrus, metestrus, and diestrus), revealing a negative correlation of circulating estrogens with ERα expression, whereas ERβ was stable. Our findings show that ER not only are present in both the peripheral and central auditory system but also that circulating estrogen levels down-regulate ERα expression in the auditory system and affect PPI and the latency of ASR, suggesting a key role of ERα as a hormone-induced modulator of the auditory system and behavior.
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Affiliation(s)
- Konstantina Charitidi
- Department of Physiology and Pharmacology, Karolinska Institutet, von Eulers Väg 8, Stockholm 17177, Sweden
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165
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Wharton W, Gleason CE, Olson SRMS, Carlsson CM, Asthana S. Neurobiological Underpinnings of the Estrogen - Mood Relationship. CURRENT PSYCHIATRY REVIEWS 2012; 8:247-256. [PMID: 23990808 PMCID: PMC3753111 DOI: 10.2174/157340012800792957] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Women are at a higher risk than men to develop mood disorders and depression. The increased risk is associated with fluctuating estrogen levels that occur during reproductive cycle events, particularly during the menopausal transition, a time characterized by drastic fluctuations in estrogen levels and increases in new onset and recurrent depression. Conversely, recent data show that hormone therapy, particularly transdermal estradiol formulations, may prevent mood disorders or even serve as a treatment regimen for women with diagnosed mood disturbances via estrogen regulation. While the exact mechanism is unknown, there is compelling scientific evidence indicating the neuromodulatory and neuroprotective effects of estrogen, which are directly relevant to mood symptomotology. Specifically, affective regulation has been linked to neural structures rich in estrogen receptors and estrogenic regulation of neurotransmitters. While a wealth of basic science, observational and clinical research support this rationale, potential mediating variables, such as estrogen formulation, proximity of administration to menopause, and the addition of progestins should be considered. Furthermore, the nature of postmenopausal exogenous hormone formulations in relation to premenopausal endogenous levels, as well as the ratio of estrone to estradiol warrant consideration.
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Affiliation(s)
- Whitney Wharton
- University of Wisconsin, Alzheimer’s Disease Research Center
- University of Wisconsin, School of Medicine and Public Health, Madison, Wisconsin
- Geriatric Research Education and Clinical Center, William S. Middleton Memorial Veterans Hospital, Madison, Wisconsin
| | - Carey E. Gleason
- University of Wisconsin, Alzheimer’s Disease Research Center
- University of Wisconsin, School of Medicine and Public Health, Madison, Wisconsin
- Geriatric Research Education and Clinical Center, William S. Middleton Memorial Veterans Hospital, Madison, Wisconsin
| | - Sandra R. M. S. Olson
- University of Wisconsin, Alzheimer’s Disease Research Center
- University of Wisconsin, School of Medicine and Public Health, Madison, Wisconsin
- Geriatric Research Education and Clinical Center, William S. Middleton Memorial Veterans Hospital, Madison, Wisconsin
| | - Cynthia M. Carlsson
- University of Wisconsin, Alzheimer’s Disease Research Center
- University of Wisconsin, School of Medicine and Public Health, Madison, Wisconsin
- Geriatric Research Education and Clinical Center, William S. Middleton Memorial Veterans Hospital, Madison, Wisconsin
| | - Sanjay Asthana
- University of Wisconsin, Alzheimer’s Disease Research Center
- University of Wisconsin, School of Medicine and Public Health, Madison, Wisconsin
- Geriatric Research Education and Clinical Center, William S. Middleton Memorial Veterans Hospital, Madison, Wisconsin
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166
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Yao J, Irwin R, Chen S, Hamilton R, Cadenas E, Brinton RD. Ovarian hormone loss induces bioenergetic deficits and mitochondrial β-amyloid. Neurobiol Aging 2012; 33:1507-21. [PMID: 21514693 PMCID: PMC3181273 DOI: 10.1016/j.neurobiolaging.2011.03.001] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2010] [Revised: 02/15/2011] [Accepted: 03/01/2011] [Indexed: 01/08/2023]
Abstract
Previously, we demonstrated that reproductive senescence was associated with mitochondrial deficits comparable to those of female triple-transgenic Alzheimer's mice (3xTgAD). Herein, we investigated the impact of chronic ovarian hormone deprivation and 17β-estradiol (E2) replacement on mitochondrial function in nontransgenic (nonTg) and 3xTgAD female mouse brain. Depletion of ovarian hormones by ovariectomy (OVX) in nontransgenic mice significantly decreased brain bioenergetics, and induced mitochondrial dysfunction and oxidative stress. In 3xTgAD mice, OVX significantly exacerbated mitochondrial dysfunction and induced mitochondrial β-amyloid and β-amyloid (Aβ)-binding-alcohol-dehydrogenase (ABAD) expression. Treatment with E2 at OVX prevented OVX-induced mitochondrial deficits, sustained mitochondrial bioenergetic function, decreased oxidative stress, and prevented mitochondrial β-amyloid and ABAD accumulation. In vitro, E2 increased maximal mitochondrial respiration in neurons and basal and maximal respiration in glia. Collectively, these data demonstrate that ovarian hormone loss induced a mitochondrial phenotype comparable to a transgenic female model of Alzheimer's disease (AD), which was prevented by E2. These findings provide a plausible mechanism for increased risk of Alzheimer's disease in premenopausally oophorectomized women while also suggesting a therapeutic strategy for prevention.
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Affiliation(s)
- Jia Yao
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, California 90033
| | - Ronald Irwin
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, California 90033
| | - Shuhua Chen
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, California 90033
| | - Ryan Hamilton
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, California 90033
| | - Enrique Cadenas
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, California 90033
| | - Roberta Diaz Brinton
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, California 90033
- Department of Neurology, Keck School of Medicine, University of Southern California, Los Angeles, California 90033
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167
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Diaz Brinton R. Minireview: translational animal models of human menopause: challenges and emerging opportunities. Endocrinology 2012; 153:3571-8. [PMID: 22778227 PMCID: PMC3404353 DOI: 10.1210/en.2012-1340] [Citation(s) in RCA: 173] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2012] [Accepted: 05/31/2012] [Indexed: 02/02/2023]
Abstract
Increasing importance is placed on the translational validity of animal models of human menopause to discern risk vs. benefit for prediction of outcomes after therapeutic interventions and to develop new therapeutic strategies to promote health. Basic discovery research conducted over many decades has built an extensive body of knowledge regarding reproductive senescence across mammalian species upon which to advance animal models of human menopause. Modifications to existing animal models could rapidly address translational gaps relevant to clinical issues in human menopausal health, which include the impact of 1) chronic ovarian hormone deprivation and hormone therapy, 2) clinically relevant hormone therapy regimens (cyclic vs. continuous combined), 3) clinically relevant hormone therapy formulations, and 4) windows of opportunity and optimal duration of interventions. Modifications in existing animal models to more accurately represent human menopause and clinical interventions could rapidly provide preclinical translational data to predict outcomes regarding unresolved clinical issues relevant to women's menopausal health. Development of the next generation of animal models of human menopause could leverage advances in identifying genotypic variations in estrogen and progesterone receptors to develop personalized menopausal care and to predict outcomes of interventions for protection against or vulnerability to disease. Key to the success of these models is the close coupling between the translational target and the range of predictive validity. Preclinical translational animal models of human menopause need to keep pace with changes in clinical practice. With focus on predictive validity and strategic use of advances in genetic and epigenetic science, new animal models of human menopause have the opportunity to set new directions for menopausal clinical care for women worldwide.
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Affiliation(s)
- Roberta Diaz Brinton
- Pharmacology and Pharmaceutical Sciences, University of Southern California, School of Pharmacy, 1985 Zonal Avenue, PSC-502, Los Angeles, California 90033, USA.
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168
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Srivastava DP. Two-step wiring plasticity--a mechanism for estrogen-induced rewiring of cortical circuits. J Steroid Biochem Mol Biol 2012; 131:17-23. [PMID: 22349412 DOI: 10.1016/j.jsbmb.2012.01.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2011] [Revised: 10/20/2011] [Accepted: 01/15/2012] [Indexed: 12/18/2022]
Abstract
Estrogens have been shown to exert powerful effects on cognitive behaviors mediated by several areas of the brain including the cortex. Remodeling of spiny synapses is a key step in the rewiring of neuronal circuitry thought to underlie the processing and storage of information in the forebrain. Whereas estrogen has been shown to regulate synapse structure and function, we are only just starting to understand the molecular and cellular underpinnings of how estrogens can modulate neuronal circuits. Here I will review recent molecular and cellular work that offers a potential mechanism of how estrogen may modulate synapse structure and function of cortical neurons. This mechanism allows cortical neurons to respond to activity-dependent stimuli with greater efficacy in a cellular model termed "Two-Step Wiring Plasticity". This novel form of spine plasticity thus provides insight into how estrogens may modulate the rewiring of neuronal circuits, underlying its ability to influencing cortically based behaviors. This article is part of a Special Issue entitled 'Neurosteroids'.
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Affiliation(s)
- Deepak P Srivastava
- Department of Neuroscience & Centre for the Cellular Basis of Behaviour, The James Black Centre, King's College London, Institute of Psychiatry, London, UK.
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169
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Singh C, Liu L, Wang JM, Irwin RW, Yao J, Chen S, Henry S, Thompson RF, Brinton RD. Allopregnanolone restores hippocampal-dependent learning and memory and neural progenitor survival in aging 3xTgAD and nonTg mice. Neurobiol Aging 2012; 33:1493-506. [PMID: 21803451 PMCID: PMC3232295 DOI: 10.1016/j.neurobiolaging.2011.06.008] [Citation(s) in RCA: 102] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2010] [Revised: 04/24/2011] [Accepted: 06/08/2011] [Indexed: 12/20/2022]
Abstract
We previously demonstrated that allopregnanolone (APα) increased proliferation of neural progenitor cells and reversed neurogenic and cognitive deficits prior to Alzheimer's disease (AD) pathology (Wang, J.M., Johnston, P.B., Ball, B.G., Brinton, R.D., 2005. The neurosteroid allopregnanolone promotes proliferation of rodent and human neural progenitor cells and regulates cell-cycle gene and protein expression. J. Neurosci. 25, 4706-4718; Wang, J.M., Singh, C., Liu, L., Irwin, R.W., Chen, S., Chung, E.J., Thompson, R.F., Brinton, R.D., 2010. Allopregnanolone reverses neurogenic and cognitive deficits in mouse model of Alzheimer's disease. Proc. Natl. Acad. Sci. U. S. A. 107, 6498-6503). Herein, we determined efficacy of APα to restore neural progenitor cell survival and associative learning and memory subsequent to AD pathology in male 3xTgAD mice and their nontransgenic (nonTg) counterparts. APα significantly increased survival of bromodeoxyuridine positive (BrdU+) cells and hippocampal-dependent associative learning and memory in 3xTgAD mice in the presence of intraneuronal amyloid beta (Aβ) whereas APα was ineffective subsequent to development of extraneuronal Aβ plaques. Restoration of hippocampal-dependent associative learning was maximal by the first day and sustained throughout behavioral training. Learning and memory function in APα-treated 3xTgAD mice was 100% greater than vehicle-treated and comparable to maximal normal nonTg performance. In aged 15-month-old nonTg mice, APα significantly increased survival of bromodeoxyuridine-positive cells and hippocampal-dependent associative learning and memory. Results provide preclinical evidence that APα promoted survival of newly generated cells and restored cognitive performance in the preplaque phase of AD pathology and in late-stage normal aging.
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Affiliation(s)
- Chanpreet Singh
- Neuroscience Program, University of Southern California, Los Angeles, CA 90089, USA
| | - Lifei Liu
- Neuroscience Program, University of Southern California, Los Angeles, CA 90089, USA
| | - Jun Ming Wang
- Department of Pathology, University of Mississippi Medical Center, 2500 N State St. Jackson, MS 39216
| | - Ronald W. Irwin
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 900089, USA
| | - Jia Yao
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 900089, USA
| | - Shuhua Chen
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 900089, USA
| | - Sherry Henry
- Department of Pathology, University of Mississippi Medical Center, 2500 N State St. Jackson, MS 39216
| | - Richard F. Thompson
- Neuroscience Program, University of Southern California, Los Angeles, CA 90089, USA
| | - Roberta Diaz Brinton
- Neuroscience Program, University of Southern California, Los Angeles, CA 90089, USA
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 900089, USA
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170
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Cory-Slechta DA, Virgolini MB, Liu S, Weston D. Enhanced stimulus sequence-dependent repeated learning in male offspring after prenatal stress alone or in conjunction with lead exposure. Neurotoxicology 2012; 33:1188-202. [PMID: 22796262 DOI: 10.1016/j.neuro.2012.06.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Revised: 06/29/2012] [Accepted: 06/29/2012] [Indexed: 10/28/2022]
Abstract
Both lead (Pb) exposure and prenatal stress (PS) can produce cognitive deficits, and in a prior study we demonstrated enhanced cognitive deficits in repeated learning of female rats exposed to both of these developmental insults (Cory-Slechta et al., 2010). However, PS can also lead to improved cognitive outcomes that are both gender- and context-dependent. Thus, the current study examined whether Pb ± PS likewise produced repeated learning deficits in males, either after maternal or lifetime Pb exposure. Repeated learning was evaluated using a multiple schedule of repeated learning and performance that required learning 3-response sequences in male offspring that had been subjected to either maternal Pb (0 or 150 ppm) or lifetime Pb exposure (0 or 50 ppm) beginning two months prior to dam breeding, to prenatal immobilization restraint stress (gestational days 16-17), or to both Pb and PS. Blood Pb, corticosterone, hippocampal glucocorticoid receptor density and brain monoamines were also measured. In contrast to outcomes in females, sequence-specific enhancements of repeated learning accuracy were produced by PS, particularly when combined with Pb, results that appeared to be more robust in combination with lifetime than maternal Pb exposure. A common behavioral mechanism of these improvements appears to be an increased reinforcement density associated with increased response rates and shorter session times seen with PS ± Pb that could shorten time to reinforcement. Trends toward lower levels of nucleus accumbens dopamine activity seen after both maternal Pb and lifetime Pb combined with PS suggest a possible role for this region/neurotransmitter in enhanced accuracy, whereas PS ± Pb-induced corticosterone changes did not exhibit an obvious systematic relationship to accuracy enhancements. While PS ± Pb-based increases in accuracy appear to be an improved outcome, the benefits of increased response rate are by no means universal, but highly context-dependent and can lead to adverse behavioral effects in other conditions.
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Affiliation(s)
- D A Cory-Slechta
- Department of Environmental Medicine, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA.
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171
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Genzel L, Kiefer T, Renner L, Wehrle R, Kluge M, Grözinger M, Steiger A, Dresler M. Sex and modulatory menstrual cycle effects on sleep related memory consolidation. Psychoneuroendocrinology 2012; 37:987-98. [PMID: 22153362 DOI: 10.1016/j.psyneuen.2011.11.006] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2011] [Revised: 11/14/2011] [Accepted: 11/14/2011] [Indexed: 10/14/2022]
Abstract
The benefit of sleep in general for memory consolidation is well known. The relevance of sleep characteristics and the influence of hormones are not well studied. We explored the effects of a nap on memory consolidation of motor (finger-tapping-task) and verbal (associated-word-pairs) tasks in following settings: A: young, healthy males and females during early-follicular phase (n=40) and B: females during mid-luteal and early-follicular phase in the menstrual cycle (n=15). We found a sex and in women a menstrual cycle effect on memory performance following a nap. Men performed significantly better after a nap and women did so only in the mid-luteal phase of their menstrual cycle. Only the men and the women in their mid-luteal phase experienced a significant increase in spindle activity after learning. Furthermore, in women estrogen correlated significantly with the offline change in declarative learning and progesterone with motor learning. The ratio of the 2nd and 4th digit, which has been associated to fetal sex hormones and cognitive sex differences, significantly predicted the average performance of the female subjects in the learning tasks. Our results demonstrate that sleep-related memory consolidation has a higher complexity and more influencing factors than previously assumed. There is a sex and menstrual cycle effect, which seems to be mediated by female hormones and sleep spindles. Further, contrary to previous reports, consolidation of a simple motor task can be induced by a 45 min NREM sleep nap, thus not dependent on REM sleep.
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Affiliation(s)
- Lisa Genzel
- Max Planck Institute of Psychiatry, Kreapelinstr.2-10, 80804 Munich, Germany.
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172
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Reiman EM, Brinton RD, Katz R, Petersen RC, Negash S, Mungas D, Aisen PS. Considerations in the design of clinical trials for cognitive aging. J Gerontol A Biol Sci Med Sci 2012; 67:766-72. [PMID: 22573913 PMCID: PMC3391068 DOI: 10.1093/gerona/gls124] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Accepted: 03/29/2012] [Indexed: 12/25/2022] Open
Abstract
What will it take to develop interventions for the treatment of age-related cognitive decline? Session V of the Summit provided perspectives on the design of clinical trials to evaluate promising but unproven interventions, and some of the steps needed to accelerate the discovery and evaluation of promising treatments. It considered strategies to further characterize the biological and cognitive changes associated with normal aging and their translation into the development of new treatments. It provided regulatory, scientific, and clinical perspectives about neurocognitive aging treatments, their potential benefits and risks, and the strategies and endpoints needed to evaluate them in the most rapid, rigorous, and clinically meaningful way. It considered lessons learned from the study of Alzheimer's disease, the promising roles of biomarkers in neurocognitive aging research, and ways to help galvanize the scientific study and treatment of neurocognitive aging.
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Affiliation(s)
- Eric M Reiman
- Banner Alzheimer's Institute, Banner Research, Translational Genomics Research Institute, University of Arizona College of Medicine, and Arizona Alzheimer's Consortium, Phoenix AZ 85006, USA.
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173
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Screening estrogenic activities of chemicals or mixtures in vivo using transgenic (cyp19a1b-GFP) zebrafish embryos. PLoS One 2012; 7:e36069. [PMID: 22586461 PMCID: PMC3346763 DOI: 10.1371/journal.pone.0036069] [Citation(s) in RCA: 141] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2012] [Accepted: 03/30/2012] [Indexed: 11/19/2022] Open
Abstract
The tg(cyp19a1b-GFP) transgenic zebrafish expresses GFP (green fluorescent protein) under the control of the cyp19a1b gene, encoding brain aromatase. This gene has two major characteristics: (i) it is only expressed in radial glial progenitors in the brain of fish and (ii) it is exquisitely sensitive to estrogens. Based on these properties, we demonstrate that natural or synthetic hormones (alone or in binary mixture), including androgens or progestagens, and industrial chemicals induce a concentration-dependent GFP expression in radial glial progenitors. As GFP expression can be quantified by in vivo imaging, this model presents a very powerful tool to screen and characterize compounds potentially acting as estrogen mimics either directly or after metabolization by the zebrafish embryo. This study also shows that radial glial cells that act as stem cells are direct targets for a large panel of endocrine disruptors, calling for more attention regarding the impact of environmental estrogens and/or certain pharmaceuticals on brain development. Altogether these data identify this in vivo bioassay as an interesting alternative to detect estrogen mimics in hazard and risk assessment perspective.
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174
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Hormone replacement therapy and risk for neurodegenerative diseases. Int J Alzheimers Dis 2012; 2012:258454. [PMID: 22548198 PMCID: PMC3324889 DOI: 10.1155/2012/258454] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Revised: 01/17/2012] [Accepted: 01/18/2012] [Indexed: 02/02/2023] Open
Abstract
Over the past two decades, there has been a significant amount of research investigating the risks and benefits of hormone replacement therapy (HRT) with regards to neurodegenerative disease. Here, we review basic science studies, randomized clinical trials, and epidemiological studies, and discuss the putative neuroprotective effects of HRT in the context of Alzheimer's disease, Parkinson's disease, frontotemporal dementia, and HIV-associated neurocognitive disorder. Findings to date suggest a reduced risk of Alzheimer's disease and improved cognitive functioning of postmenopausal women who use 17β-estradiol. With regards to Parkinson's disease, there is consistent evidence from basic science studies for a neuroprotective effect of 17β-estradiol; however, results of clinical and epidemiological studies are inconclusive at this time, and there is a paucity of research examining the association between HRT and Parkinson's-related neurocognitive impairment. Even less understood are the effects of HRT on risk for frontotemporal dementia and HIV-associated neurocognitive disorder. Limits to the existing research are discussed, along with proposed future directions for the investigation of HRT and neurodegenerative diseases.
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175
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Foster TC. Role of estrogen receptor alpha and beta expression and signaling on cognitive function during aging. Hippocampus 2012; 22:656-69. [PMID: 21538657 PMCID: PMC3704216 DOI: 10.1002/hipo.20935] [Citation(s) in RCA: 182] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/06/2011] [Indexed: 12/24/2022]
Abstract
This review presents evidence for the idea that the expression of estrogen receptor alpha and beta (ERα and ERβ) interacts with the level of estradiol (E2) to influence the etiology of age-related cognitive decline and responsiveness to E2 treatments. There is a nonmonotonic dose response curve for E2 influences on behavior and transcription. Evidence is mounting to indicate that the dose response curve is shifted according to the relative expression of ERα and ERβ. Recent work characterizing age-related changes in the expression of ERα and ERβ in the hippocampus, as well as studies using mutant mice, and viral mediated delivery of estrogen receptors indicate that an age-related shift in ERα/ERβ expression, combined with declining gonadal E2 can impact transcription, cell signaling, neuroprotection, and neuronal growth. Finally, the role of ERα/ERβ on rapid E2 signaling and synaptogenesis as it relates to hippocampal aging is discussed.
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Affiliation(s)
- Thomas C Foster
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, Florida 32610-0244, USA.
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176
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Benmansour S, Weaver RS, Barton AK, Adeniji OS, Frazer A. Comparison of the effects of estradiol and progesterone on serotonergic function. Biol Psychiatry 2012; 71:633-41. [PMID: 22225849 PMCID: PMC3307822 DOI: 10.1016/j.biopsych.2011.11.023] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2011] [Revised: 11/29/2011] [Accepted: 11/30/2011] [Indexed: 12/27/2022]
Abstract
BACKGROUND Ovarian hormones may contribute to the vulnerability to depression, as well as to the response to antidepressants (ADs). Previously, we reported that acute systemic treatment with estradiol or progesterone blocked the ability of the selective serotonin reuptake inhibitor, fluvoxamine, to inhibit serotonin transporter function in ovariectomized rats. In this study, behavioral consequences, as well as receptor mechanisms underlying these hormonal effects, were investigated. METHODS Using the forced swimming test, the acute effect of estradiol and/or progesterone on fluvoxamine's AD-like effects was investigated. Using in vivo chronoamperometry, the effect of local application of estradiol or progesterone into the hippocampus of ovariectomized rats on serotonin (5-HT) clearance, as well as on the ability of fluvoxamine to slow 5-HT clearance, were investigated. RESULTS The decreased immobility and increased swimming caused by fluvoxamine in the forced swimming test was blocked in rats treated with estradiol and/or progesterone. Local application of estradiol, but not progesterone, slowed 5-HT clearance and both hormones blocked the ability of fluvoxamine to slow 5-HT clearance. Use of hormone receptor agonists and antagonists, revealed that the effects of estradiol are mediated by activation of membrane, as well as nuclear estrogen receptors (ER). The AD-like effect of estradiol involved ER beta and G-protein coupled receptor 30, whereas its blockade of fluvoxamine's effects was ER alpha-mediated. The effects of progesterone occurred solely by activation of intracellular progesterone receptors. CONCLUSIONS Targeting of ER beta or G-protein coupled receptor 30 might reveal a strategy to permit beneficial effects of estrogen without its deleterious effect on selective serotonin reuptake inhibitor efficacy.
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Affiliation(s)
- Saloua Benmansour
- Department of Pharmacology, University of Texas Health Science Center at San Antonio, 78229-3900, USA.
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177
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Wang JM, Hou X, Adeosun S, Hill R, Henry S, Paul I, Irwin RW, Ou XM, Bigler S, Stockmeier C, Brinton RD, Gomez-Sanchez E. A dominant negative ERβ splice variant determines the effectiveness of early or late estrogen therapy after ovariectomy in rats. PLoS One 2012; 7:e33493. [PMID: 22428062 PMCID: PMC3302771 DOI: 10.1371/journal.pone.0033493] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Accepted: 02/14/2012] [Indexed: 11/18/2022] Open
Abstract
The molecular mechanisms for the discrepancy in outcome of initiating estrogen therapy (ET) around peri-menopause or several years after menopause in women are unknown. We hypothesize that the level of expression of a dominant negative estrogen receptor (ER) β variant, ERβ2, may be a key factor determining the effectiveness of ET in post-menopausal women. We tested this hypothesis in ovariectomized nine month-old (an age when irregular estrous cycles occur) female Sprague Dawley rats. Estradiol treatment was initiated either 6 days (Early ET, analogous to 4 months post-menopause in humans), or 180 days (Late ET, analogous to 11 years post-menopause in humans) after ovariectomy. Although ERβ2 expression increased in all OVX rats, neurogenic and neuroprotective responses to estradiol differed in Early and Late ET. Early ET reduced ERβ2 expression in both hippocampus and white blood cells, increased the hippocampal cell proliferation as assessed by Ki-67 expression, and improved mobility in the forced swim test. Late ET resulted in either no or modest effects on these parameters. There was a close correlation between the degree of ERβ2 expression and the preservation of neural effects by ET after OVX in rats, supporting the hypothesis that persistent elevated levels of ERβ2 are a molecular basis for the diminished effectiveness of ET in late post-menopausal women. The correlation between the expression of ERβ2 in circulating white blood cells and brain cells suggests that ERβ2 expression in peripheral blood cells may be an easily accessible marker to predict the effective window for ET in the brain.
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Affiliation(s)
- Jun Ming Wang
- Department of Pathology, University of Mississippi Medical Center, Jackson, Mississippi, United States of America.
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178
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The ageing cortical synapse: hallmarks and implications for cognitive decline. Nat Rev Neurosci 2012; 13:240-50. [PMID: 22395804 DOI: 10.1038/nrn3200] [Citation(s) in RCA: 640] [Impact Index Per Article: 53.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Normal ageing is associated with impairments in cognitive function, including memory. These impairments are linked, not to a loss of neurons in the forebrain, but to specific and relatively subtle synaptic alterations in the hippocampus and prefrontal cortex. Here, we review studies that have shed light on the cellular and synaptic changes observed in these brain structures during ageing that can be directly related to cognitive decline in young and aged animals. We also discuss the influence of the hormonal status on these age-related alterations and recent progress in the development of therapeutic strategies to limit the impact of ageing on memory and cognition in humans.
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179
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Manaye KF, Allard JS, Kalifa S, Drew AC, Xu G, Ingram DK, de Cabo R, Mouton PR. 17α-estradiol attenuates neuron loss in ovariectomized Dtg AβPP/PS1 mice. J Alzheimers Dis 2012; 23:629-39. [PMID: 21157032 DOI: 10.3233/jad-2010-100993] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Quantitative microanalysis of brains from patients with Alzheimer's disease (AD) find neuronal loss and neuroinflammation in structures that control cognitive function. Though historically difficult to recapitulate in experimental models, several groups have recently reported that by middle-age, transgenic mice that co-express high levels of two AD-associated mutations, amyloid-β protein precursor (AβPP(swe)) and presenilin 1 (PS1(ΔE9)), undergo significant AD-type neuron loss in sub-cortical nuclei with heavy catecholaminergic projections to the hippocampal formation. Here we report that by 13 months of age these dtg AβPP(swe)/PS1(ΔE9) mice also show significant loss of pyramidal neuron in a critical region for learning and memory, the CA1 subregion of hippocampus, as a direct function of amyloid-β (Aβ) aggregation. We used these mice to test whether 17α-estradiol (17αE2), a less feminizing and non-carcinogenic enantiomer of 17β-estradiol, protects against this CA1 neuron loss. Female dtg AβPP(swe)/PS1(ΔE9) mice were ovariectomized at 8-9 months of age and treated for 60 days with either 17αE2 or placebo via subcutaneous pellets. Computerized stereology revealed that 17αE2 ameliorated the loss of neurons in CA1 and reduced microglial activation in the hippocampus. These findings support the view that 17αE2, which may act through non-genomic mechanisms independent of traditional estrogen receptors, could prevent or delay the progression of AD in older men and women.
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Affiliation(s)
- Kebreten F Manaye
- Department of Physiology & Biophysics, College of Medicine, Howard University, Washington, DC 20059, USA.
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180
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Abstract
Sex steroids exert actions of paramount importance on brain cells. They contribute to shape the central nervous system during embryo development. They modulate the formation and the turnover of the interconnections between neurons. They control the function of glial cells. And they do it through a signaling machinery that is apparently simple, but that hides a level of complexity that has been unveiled only in part. Different receptor isoforms, different interactions between receptors and co-regulators, chains of events originating at the cell membrane and leading to effects in the nucleus (or the other way around) all interact to determine selective modulations of brain cells. All these actions end up in phenomenal effects on brain function that change through adolescence, pregnancy, adulthood, up to menopause and ageing. Many of these actions are relevant for degenerative processes and research may offer soon new strategies to counteract these diseases.
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Affiliation(s)
- Paolo Mannella
- Department of Reproductive Medicine and Child Development, Division of Obstetrics and Gynecology, University of Pisa, Pisa, Italy
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181
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Irwin RW, Yao J, To J, Hamilton RT, Cadenas E, Brinton RD. Selective oestrogen receptor modulators differentially potentiate brain mitochondrial function. J Neuroendocrinol 2012; 24:236-48. [PMID: 22070562 PMCID: PMC3264398 DOI: 10.1111/j.1365-2826.2011.02251.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The mitochondrial energy-transducing capacity of the brain is important for long-term neurological health and is influenced by endocrine hormone responsiveness. The present study aimed to determine the role of oestrogen receptor (ER) subtypes in regulating mitochondrial function using selective agonists for ERα (propylpyrazoletriol; PPT) and ERβ (diarylpropionitrile; DPN). Ovariectomised female rats were treated with 17β-oestradiol (E(2) ), PPT, DPN or vehicle control. Both ER selective agonists significantly increased the mitochondrial respiratory control ratio and cytochrome oxidase (COX) activity relative to vehicle. Western blots of purified whole brain mitochondria detected ERα and, to a greater extent, ERβ localisation. Pre-treatment with DPN, an ERβ agonist, significantly increased ERβ association with mitochondria. In the hippocampus, DPN activated mitochondrial DNA-encoded COX I expression, whereas PPT was ineffective, indicating that mechanistically ERβ, and not ERα, activated mitochondrial transcriptional machinery. Both selective ER agonists increased protein expression of nuclear DNA-encoded COX IV, suggesting that activation of ERβ or ERα is sufficient. Selective ER agonists up-regulated a panel of bioenergetic enzymes and antioxidant defence proteins. Up-regulated proteins included pyruvate dehydrogenase, ATP synthase, manganese superoxide dismutase and peroxiredoxin V. In vitro, whole cell metabolism was assessed in live primary cultured hippocampal neurones and mixed glia. The results of analyses conducted in vitro were consistent with data obtained in vivo. Furthermore, lipid peroxides, accumulated as a result of hormone deprivation, were significantly reduced by E(2) , PPT and DPN. These findings suggest that the activation of both ERα and ERβ is differentially required to potentiate mitochondrial function in brain. As active components in hormone therapy, synthetically designed oestrogens as well as natural phyto-oestrogen cocktails can be tailored to improve brain mitochondrial endpoints.
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Affiliation(s)
- Ronald W. Irwin
- Department of Pharmacology and Pharmaceutical Sciences, University of Southern California, Pharmaceutical Sciences Center, Los Angeles, California, 90033
| | - Jia Yao
- Department of Pharmacology and Pharmaceutical Sciences, University of Southern California, Pharmaceutical Sciences Center, Los Angeles, California, 90033
| | - Jimmy To
- Department of Pharmacology and Pharmaceutical Sciences, University of Southern California, Pharmaceutical Sciences Center, Los Angeles, California, 90033
| | - Ryan T. Hamilton
- Department of Pharmacology and Pharmaceutical Sciences, University of Southern California, Pharmaceutical Sciences Center, Los Angeles, California, 90033
| | - Enrique Cadenas
- Department of Pharmacology and Pharmaceutical Sciences, University of Southern California, Pharmaceutical Sciences Center, Los Angeles, California, 90033
| | - Roberta Diaz Brinton
- Department of Pharmacology and Pharmaceutical Sciences, University of Southern California, Pharmaceutical Sciences Center, Los Angeles, California, 90033
- Program in Neuroscience, University of Southern California, Los Angeles, California, 90033
- Address correspondence to: Roberta Diaz Brinton, Ph.D., Department of Pharmacology and Pharmaceutical Sciences, University of Southern California, Pharmaceutical Sciences Center, 1985 Zonal Avenue, Los Angeles, California, 90089, Tel. 323-442-1428; Fax. 323-442-1489;
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182
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Stolp H, Neuhaus A, Sundramoorthi R, Molnár Z. The Long and the Short of it: Gene and Environment Interactions During Early Cortical Development and Consequences for Long-Term Neurological Disease. Front Psychiatry 2012; 3:50. [PMID: 22701439 PMCID: PMC3372875 DOI: 10.3389/fpsyt.2012.00050] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2011] [Accepted: 05/01/2012] [Indexed: 01/21/2023] Open
Abstract
Cortical development is a complex amalgamation of proliferation, migration, differentiation, and circuit formation. These processes follow defined timescales and are controlled by a combination of intrinsic and extrinsic factors. It is currently unclear how robust and flexible these processes are and whether the developing brain has the capacity to recover from disruptions. What is clear is that there are a number of cognitive disorders or conditions that are elicited as a result of disrupted cortical development, although it may take a long time for the full pathophysiology of the conditions to be realized clinically. The critical window for the manifestation of a neurodevelopmental disorder is prolonged, and there is the potential for a complex interplay between genes and environment. While there have been extended investigations into the genetic basis of a number of neurological and mental disorders, limited definitive associations have been discovered. Many environmental factors, including inflammation and stress, have been linked to neurodevelopmental disorders, and it may be that a better understanding of the interplay between genes and environment will speed progress in this field. In particular, the development of the brain needs to be considered in the context of the whole materno-fetal unit as the degree of the metabolic, endocrine, or inflammatory responses, for example, will greatly influence the environment in which the brain develops. This review will emphasize the importance of extending neurodevelopmental studies to the contribution of the placenta, vasculature, cerebrospinal fluid, and to maternal and fetal immune response. These combined investigations are more likely to reveal genetic and environmental factors that influence the different stages of neuronal development and potentially lead to the better understanding of the etiology of neurological and mental disorders such as autism, epilepsy, cerebral palsy, and schizophrenia.
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Affiliation(s)
- Helen Stolp
- Department of Physiology, Anatomy and Genetics, University of Oxford Oxford, UK
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183
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Abstract
Oestradiol exerts a profound influence upon multiple brain circuits. For the most part, these effects are mediated by oestrogen receptor (ER)α. We review here the roles of ERβ, the other ER isoform, in mediating rodent oestradiol-regulated anxiety, aggressive and sexual behaviours, the control of gonadotrophin secretion, and adult neurogenesis. Evidence exists for: (i) ERβ located in the paraventricular nucleus underpinning the suppressive influence of oestradiol on the stress axis and anxiety-like behaviour; (ii) ERβ expressed in gonadotrophin-releasing hormone neurones contributing to oestrogen negative-feedback control of gonadotrophin secretion; (iii) ERβ controlling the offset of lordosis behaviour; (iv) ERβ suppressing aggressive behaviour in males; (v) ERβ modulating responses to social stimuli; and (vi) ERβ in controlling adult neurogenesis. This review highlights two major themes; first, ERβ and ERα are usually tightly inter-related in the oestradiol-dependent control of a particular brain function. For example, even though oestradiol feedback to control reproduction occurs principally through ERα-dependent mechanisms, modulatory roles for ERβ also exist. Second, the roles of ERα and ERβ within a particular neural network may be synergistic or antagonistic. Examples of the latter include the role of ERα to enhance, and ERβ to suppress, anxiety-like and aggressive behaviours. Splice variants such as ERβ2, acting as dominant negative receptors, are of further particular interest because their expression levels may reflect preceeding oestradiol exposure of relevance to oestradiol replacement therapy. Together, this review highlights the predominant modulatory, but nonetheless important, roles of ERβ in mediating the many effects of oestradiol upon adult brain function.
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Affiliation(s)
- R. J. Handa
- Department of Basic Medical Sciences, University of Arizona College of Medicine - Phoenix, Phoenix, AZ, USA
| | - S. Ogawa
- Laboratory of Behavioral Neuroendocrinology, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - J. M. Wang
- Department of Pathology, Pharmacology and Toxicology, Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS, USA
| | - A. E. Herbison
- Centre for Neuroendocrinology and Department of Physiology, University of Otago, Dunedin, New Zealand
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184
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Brion F, Le Page Y, Piccini B, Cardoso O, Tong SK, Chung BC, Kah O. Screening estrogenic activities of chemicals or mixtures in vivo using transgenic (cyp19a1b-GFP) zebrafish embryos. PLoS One 2012. [PMID: 22586461 DOI: 10.1372/journal.pone.0036069] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/22/2023] Open
Abstract
The tg(cyp19a1b-GFP) transgenic zebrafish expresses GFP (green fluorescent protein) under the control of the cyp19a1b gene, encoding brain aromatase. This gene has two major characteristics: (i) it is only expressed in radial glial progenitors in the brain of fish and (ii) it is exquisitely sensitive to estrogens. Based on these properties, we demonstrate that natural or synthetic hormones (alone or in binary mixture), including androgens or progestagens, and industrial chemicals induce a concentration-dependent GFP expression in radial glial progenitors. As GFP expression can be quantified by in vivo imaging, this model presents a very powerful tool to screen and characterize compounds potentially acting as estrogen mimics either directly or after metabolization by the zebrafish embryo. This study also shows that radial glial cells that act as stem cells are direct targets for a large panel of endocrine disruptors, calling for more attention regarding the impact of environmental estrogens and/or certain pharmaceuticals on brain development. Altogether these data identify this in vivo bioassay as an interesting alternative to detect estrogen mimics in hazard and risk assessment perspective.
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Affiliation(s)
- François Brion
- Unité d'Ecotoxicologie in vitro et in vivo, Direction des Risques Chroniques, Institut National de l'Environnement Industriel et des Risques (INERIS), Verneuil-en-Halatte, France
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185
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Srivastava DP, Waters EM, Mermelstein PG, Kramár EA, Shors TJ, Liu F. Rapid estrogen signaling in the brain: implications for the fine-tuning of neuronal circuitry. J Neurosci 2011; 31:16056-63. [PMID: 22072656 PMCID: PMC3245715 DOI: 10.1523/jneurosci.4097-11.2011] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2011] [Revised: 09/26/2011] [Accepted: 09/27/2011] [Indexed: 12/17/2022] Open
Abstract
Rapid actions of estrogens were first described >40 years ago. However, the importance of rapid estrogen-mediated actions in the CNS is only now becoming apparent. Several lines of evidence demonstrate that rapid estrogen-mediated signaling elicits potent effects on molecular and cellular events, resulting in the "fine-tuning" of neuronal circuitry. At an ultrastructural level, the details of estrogen receptor localization and how these are regulated by the circulating hormone and age are now becoming evident. Furthermore, the mechanisms that allow membrane-associated estrogen receptors to couple with intracellular signaling pathways are also now being revealed. Elucidation of complex actions of rapid estrogen-mediated signaling on synaptic proteins, connectivity, and synaptic function in pyramidal neurons has demonstrated that this neurosteroid engages specific mechanisms in different areas of the brain. The regulation of synaptic properties most likely underlies the fine-tuning of neuronal circuitry. This in turn may influence how learned behaviors are encoded by different circuitry in male and female subjects. Importantly, as estrogens have been suggested as potential treatments of a number of disorders of the CNS, advancements in our understanding of rapid estrogen signaling in the brain will serve to aid in the development of potential novel estrogen-based treatments.
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Affiliation(s)
- Deepak P. Srivastava
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611
- Department of Neuroscience and Centre for the Cellular Basis of Behaviour, The James Black Centre, King's College London, Institute of Psychiatry, London SE5 8AF, United Kingdom
| | - Elizabeth M. Waters
- Laboratory of Neuroendocrinology, The Rockefeller University, New York, New York 10065
| | - Paul G. Mermelstein
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455
| | - Enikö A. Kramár
- Department of Psychiatry and Human Behavior, Irvine, California 92697
| | - Tracey J. Shors
- Department of Psychology and Center for Collaborative Neuroscience, Rutgers University, Piscataway, New Jersey 08854, and
| | - Feng Liu
- Neuroscience Research Unit, Pfizer Global Research and Development, Groton, Connecticut 06340
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186
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Zhao L, Yao J, Mao Z, Chen S, Wang Y, Brinton RD. 17β-Estradiol regulates insulin-degrading enzyme expression via an ERβ/PI3-K pathway in hippocampus: relevance to Alzheimer's prevention. Neurobiol Aging 2011; 32:1949-63. [PMID: 20053478 PMCID: PMC2889185 DOI: 10.1016/j.neurobiolaging.2009.12.010] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2009] [Revised: 11/13/2009] [Accepted: 12/11/2009] [Indexed: 01/11/2023]
Abstract
Insulin-degrading enzyme (IDE), an enzyme that primarily degrades insulin, has recently been demonstrated to play a significant role in the catabolism of amyloid β (Aβ) protein in the brain. Reduced IDE expression and/or activity have been associated with the etiology and development of Alzheimer's disease (AD). Using three model systems, the present investigation provides the first documentation indicating that estrogen robustly regulates the expression of IDE in normal, menopausal and early-stage AD brains. In vitro analyses in primary cultures of rat hippocampal neurons revealed that 17β-estradiol (17β-E2) increased IDE in both mRNA and protein levels in a time-dependent manner. Further pharmacological analyses indicated that 17β-E2-induced IDE expression was dependent upon estrogen receptor (ER) β and required activation of phosphatidylinositol 3-kinase (PI3-K). In vivo analyses in adult female rats revealed a brain region-specific responsive profile. Ovariectomy (OVX) induced a significant decline in IDE expression in the hippocampus, which was prevented by 17β-E2. Neither OVX nor 17β-E2 affected IDE expression in the cerebellum. In vivo analyses in triple transgenic AD (3xTg-AD) female mice revealed an inverse correlation between the age-related increase in Aβ load and the decrease in IDE expression in the hippocampal formation. Treatment with 17β-E2 attenuated Aβ accumulation/plaque formation and elevated hippocampal IDE expression in 12-month-old 3xTg-AD OVX mice. Collectively, these findings indicate that 17β-E2 regulates IDE expression in a brain region-specific manner and such a regulatory role in the hippocampus, mediated by an ERβ/PI3-K pathway, could serve as a direct mechanism underlying estrogen-mediated preventative effect against AD when initiated at the onset of menopause.
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Affiliation(s)
- Liqin Zhao
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 90033, United States
| | - Jia Yao
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 90033, United States
| | - Zisu Mao
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 90033, United States
| | - Shuhua Chen
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 90033, United States
| | - Yan Wang
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 90033, United States
| | - Roberta Diaz Brinton
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 90033, United States
- Program in Neuroscience, University of Southern California, Los Angeles, CA 90033, United States
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187
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Latimer CS, Searcy JL, Bridges MT, Brewer LD, Popović J, Blalock EM, Landfield PW, Thibault O, Porter NM. Reversal of glial and neurovascular markers of unhealthy brain aging by exercise in middle-aged female mice. PLoS One 2011; 6:e26812. [PMID: 22046366 PMCID: PMC3201977 DOI: 10.1371/journal.pone.0026812] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2011] [Accepted: 10/04/2011] [Indexed: 01/14/2023] Open
Abstract
Healthy brain aging and cognitive function are promoted by exercise. The benefits of exercise are attributed to several mechanisms, many which highlight its neuroprotective role via actions that enhance neurogenesis, neuronal morphology and/or neurotrophin release. However, the brain is also composed of glial and vascular elements, and comparatively less is known regarding the effects of exercise on these components in the aging brain. Here, we show that aerobic exercise at mid-age decreased markers of unhealthy brain aging including astrocyte hypertrophy, a hallmark of brain aging. Middle-aged female mice were assigned to a sedentary group or provided a running wheel for six weeks. Exercise decreased hippocampal astrocyte and myelin markers of aging but increased VEGF, a marker of angiogenesis. Brain vascular casts revealed exercise-induced structural modifications associated with improved endothelial function in the periphery. Our results suggest that age-related astrocyte hypertrophy/reactivity and myelin dysregulation are aggravated by a sedentary lifestyle and accompanying reductions in vascular function. However, these effects appear reversible with exercise initiated at mid-age. As this period of the lifespan coincides with the appearance of multiple markers of brain aging, including initial signs of cognitive decline, it may represent a window of opportunity for intervention as the brain appears to still possess significant vascular plasticity. These results may also have particular implications for aging females who are more susceptible than males to certain risk factors which contribute to vascular aging.
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Affiliation(s)
- Caitlin S. Latimer
- Department of Molecular and Biomedical Pharmacology, University of Kentucky College of Medicine, Lexington, Kentucky, United States of America
| | - James L. Searcy
- Department of Molecular and Biomedical Pharmacology, University of Kentucky College of Medicine, Lexington, Kentucky, United States of America
| | - Michael T. Bridges
- Department of Molecular and Biomedical Pharmacology, University of Kentucky College of Medicine, Lexington, Kentucky, United States of America
| | - Lawrence D. Brewer
- Department of Molecular and Biomedical Pharmacology, University of Kentucky College of Medicine, Lexington, Kentucky, United States of America
| | - Jelena Popović
- Department of Molecular and Biomedical Pharmacology, University of Kentucky College of Medicine, Lexington, Kentucky, United States of America
| | - Eric M. Blalock
- Department of Molecular and Biomedical Pharmacology, University of Kentucky College of Medicine, Lexington, Kentucky, United States of America
| | - Philip W. Landfield
- Department of Molecular and Biomedical Pharmacology, University of Kentucky College of Medicine, Lexington, Kentucky, United States of America
| | - Olivier Thibault
- Department of Molecular and Biomedical Pharmacology, University of Kentucky College of Medicine, Lexington, Kentucky, United States of America
| | - Nada M. Porter
- Department of Molecular and Biomedical Pharmacology, University of Kentucky College of Medicine, Lexington, Kentucky, United States of America
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188
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Grassi S, Tozzi A, Costa C, Tantucci M, Colcelli E, Scarduzio M, Calabresi P, Pettorossi VE. Neural 17β-estradiol facilitates long-term potentiation in the hippocampal CA1 region. Neuroscience 2011; 192:67-73. [PMID: 21749911 DOI: 10.1016/j.neuroscience.2011.06.078] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2011] [Revised: 06/23/2011] [Accepted: 06/28/2011] [Indexed: 10/18/2022]
Abstract
In the hippocampal formation many neuromodulators are possibly implied in the synaptic plasticity such as the long-term potentiation (LTP) induced by high-frequency stimulation (HFS) of afferent fibers. We investigated the involvement of locally synthesized neural 17β-estradiol (nE(2)) in the induction of HFS-LTP in hippocampal slices from male rats by stimulating the Schaffer collateral fibers and recording the evoked field excitatory postsynaptic potential (fEPSP) in the CA1 region. We demonstrated that either the blockade of nE(2) synthesis by the aromatase inhibitor letrozole, or the antagonism of E(2) receptors (ERs) by ICI 182,780 did not prevent the induction of HFS-LTP, but reduced its amplitude by ∼60%, without influencing its maintenance. Moreover, letrozole and ICI 182,780 did not affect the first short-term post-tetanic component of LTP and the paired-pulse facilitation (PPF). These findings demonstrate that nE(2) plays an important role in the induction phase of HFS-dependent LTP. Since the basal responses were not affected by the blocking agents, we suggest that the synthesis of nE(2) is induced or enhanced by HFS through aromatase activation. In this context, the local production of nE(2) seems to be a very effective mechanism to modulate the amplitude of LTP.
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Affiliation(s)
- S Grassi
- Dipartimento di Medicina Interna, Sezione di Fisiologia Umana, Università di Perugia, Via del Giochetto, I-06126 Perugia, Italy.
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189
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Clarkson TB, Utian WH, Barnes S, Gold EB, Basaria SS, Aso T, Kronenberg F, Frankenfeld CL, Cline JM, Landgren BM, Gallagher JC, Weaver CM, Hodis HN, Brinton RD, Maki PM. The role of soy isoflavones in menopausal health: report of The North American Menopause Society/Wulf H. Utian Translational Science Symposium in Chicago, IL (October 2010). Menopause 2011; 18:732-53. [PMID: 21685820 DOI: 10.1097/gme.0b013e31821fc8e0] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
OBJECTIVES If and to what extent soy protein, soy isoflavones, and their metabolites, including S(--)-equol, have beneficial effects on women's health is currently unclear. The North American Menopause Society (NAMS)/Utian Translational Science Symposium on Soy and Soy Isoflavones convened October 9-10, 2010, to clarify basic and clinical research findings as they relate to the risk and benefits of soy products for peri- and postmenopausal women. METHODS A working group of faculty and panelists composed of clinical and research experts in the fields of women's health and botanicals met during a 2-day translational symposium to cover the latest evidence-based science on isoflavones as they affect menopausal symptoms, breast and endometrial cancer, atherosclerosis, bone loss, and cognition. Full descriptions of the bioavailability and pharmacokinetics of isoflavones were also presented. Subspecialty groups then broke off with the goal of translating the information into a report for general medical practice and identifying further research areas. All faculty and panelists reviewed the final report, which was then approved by the NAMS Board of Trustees. RESULTS From the hundreds of studies reviewed in this report, there are mixed results of the effects on midlife women. Soy-based isoflavones are modestly effective in relieving menopausal symptoms; supplements providing higher proportions of genistein or increased in S(--)-equol may provide more benefits. Soy food consumption is associated with lower risk of breast and endometrial cancer in observational studies. The efficacy of isoflavones on bone has not been proven, and the clinical picture of whether soy has cardiovascular benefits is still evolving. Preliminary findings on cognitive benefit from isoflavone therapy support a "critical window" hypothesis wherein younger postmenopausal women derive more than older women. CONCLUSIONS Several areas for further research have been identified on soy and midlife women. More clinical studies are needed that compare outcomes among women whose intestinal bacteria have the ability to convert daidzein to equol (equol producers) with those that lack that ability (equol nonproducers) in order to determine if equol producers derive greater benefits from soy supplementation. Larger studies are needed in younger postmenopausal women, and more research is needed to understand the modes of use of soy isoflavone supplements in women. The interrelations of other dietary components on soy isoflavones consumed as a part of diet or by supplement on equol production also require further study, as do potential interactions with prescription and over-the-counter medications. And finally, greater standardization and documentation of clinical trial data of soy are needed.
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190
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Numakawa T, Matsumoto T, Numakawa Y, Richards M, Yamawaki S, Kunugi H. Protective Action of Neurotrophic Factors and Estrogen against Oxidative Stress-Mediated Neurodegeneration. J Toxicol 2011; 2011:405194. [PMID: 21776259 PMCID: PMC3135156 DOI: 10.1155/2011/405194] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2011] [Revised: 02/28/2011] [Accepted: 03/29/2011] [Indexed: 01/01/2023] Open
Abstract
Oxidative stress is involved in the pathogenesis of neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease, and Huntington's disease. Low levels of reactive oxygen species (ROS) and reactive nitrogen species (RNS) are important for maintenance of neuronal function, though elevated levels lead to neuronal cell death. A complex series of events including excitotoxicity, Ca(2+) overload, and mitochondrial dysfunction contributes to oxidative stress-mediated neurodegeneration. As expected, many antioxidants like phytochemicals and vitamins are known to reduce oxidative toxicity. Additionally, growing evidence indicates that neurotrophic factors such as brain-derived neurotrophic factor (BDNF) and estrogens significantly prevent neuronal damage caused by oxidative stress. Here, we review and discuss recent studies addressing the protective mechanisms of neurotrophic factors and estrogen within this system.
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Affiliation(s)
- Tadahiro Numakawa
- Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo 187-8502, Japan
- Core Research for Evolutional Science and Technology Program (CREST), Japan Science and Technology Agency (JST), Saitama 332-0012, Japan
| | - Tomoya Matsumoto
- Core Research for Evolutional Science and Technology Program (CREST), Japan Science and Technology Agency (JST), Saitama 332-0012, Japan
- Department of Psychiatry and Neurosciences, Division of Frontier Medical Science, Graduate School of Biomedical Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan
| | - Yumiko Numakawa
- Peptide-prima Co., Ltd., 1-25-81, Nuyamazu, Kumamoto 861-2102, Japan
| | - Misty Richards
- Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo 187-8502, Japan
- The Center for Neuropharmacology and Neuroscience, Albany Medical College, Albany, NY 12208, USA
| | - Shigeto Yamawaki
- Core Research for Evolutional Science and Technology Program (CREST), Japan Science and Technology Agency (JST), Saitama 332-0012, Japan
- Department of Psychiatry and Neurosciences, Division of Frontier Medical Science, Graduate School of Biomedical Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan
| | - Hiroshi Kunugi
- Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo 187-8502, Japan
- Core Research for Evolutional Science and Technology Program (CREST), Japan Science and Technology Agency (JST), Saitama 332-0012, Japan
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191
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Luchetti S, Huitinga I, Swaab DF. Neurosteroid and GABA-A receptor alterations in Alzheimer's disease, Parkinson's disease and multiple sclerosis. Neuroscience 2011; 191:6-21. [PMID: 21514366 DOI: 10.1016/j.neuroscience.2011.04.010] [Citation(s) in RCA: 112] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Revised: 04/03/2011] [Accepted: 04/05/2011] [Indexed: 01/17/2023]
Abstract
Steroid hormones (e.g. estrogens, androgens, progestagens) which are synthesized de novo or metabolized within the CNS are called neurosteroids. There is substantial evidence from animal studies suggesting that these steroids can affect brain function by modulating neurotransmission, and influence neuronal survival, neuronal and glial differentiation and myelination in the CNS by regulating gene expression of neurotrophic factors and anti-inflammatory molecules. Indeed, evidence is emerging that expression of the enzymes responsible for the synthesis of neurosteroids changes in neurodegenerative diseases. Some of these changes may contribute to the pathology, while others, conversely, may represent an attempted rescue program in the diseased brain. Here we review the data on changes in neurosteroid levels and neurosteroid synthesis pathways in the human brain in three neurodegenerative conditions, Alzheimers's (AD) and Parkinson's (PD) diseases and Multiple Sclerosis (MS) and the extent to which these findings may implicate protective or pathological roles for neurosteroids in the course of these diseases.Some neurosteroids can modulate neurotransmitter activity, for example, the pregnane steroids allopregnanolone and 3α5α-tetrahydro-deoxycorticosterone which are potent positive allosteric modulators of ionotropic GABA-A receptors. Therefore, neurosteroid-modulated GABA-A receptor subunit alterations found in AD and PD will also be discussed. These data imply an involvement of neurosteroid changes in the neurodegenerative and neuroinflammatory processes and suggest that they may deserve further investigation as potential therapeutic agents in AD, PD and MS. Finally, suggestions for therapeutic strategies will be included. This article is part of a Special Issue entitled: Neuroactive Steroids: Focus on Human Brain.
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Affiliation(s)
- S Luchetti
- Netherlands Institute for Neuroscience (NIN), an Institute of the Royal Netherlands Academy of Arts and Sciences, Meibergdreef 47, 1105 BA, Amsterdam, The Netherlands.
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192
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Rosati F, Sturli N, Cungi MC, Morello M, Villanelli F, Bartolucci G, Finocchi C, Peri A, Serio M, Danza G. Gonadotropin-releasing hormone modulates cholesterol synthesis and steroidogenesis in SH-SY5Y cells. J Steroid Biochem Mol Biol 2011; 124:77-83. [PMID: 21296663 DOI: 10.1016/j.jsbmb.2011.01.012] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Revised: 01/26/2011] [Accepted: 01/27/2011] [Indexed: 11/28/2022]
Abstract
Neurosteroids are involved in Central Nervous System development, brain functionality and neuroprotection but little is known about regulators of their biosynthesis. Recently gonadotropins, Gonadotropin-releasing Hormone (GnRH) and their receptors have been localized in different brain regions, such as hippocampus and cortex. Using human neuronal-like cells we found that GnRH up-regulates the expression of key genes of cholesterol and steroid synthesis when used in a narrow range around 1.0 nM. The expression of Hydroxysterol D24-reductase (seladin-1/DHCR24), that catalyzes the last step of cholesterol biosynthesis, is increased by 50% after 90 min of incubation with GnRH. StAR protein and P450 side chain cleavage (P450scc) are up-regulated by 3.3 times after 90 min and by 3.5 times after 3 h, respectively. GnRH action is mediated by LH and 1.0 nM GnRH enhances the expression of LHβ as well. A two fold increase of cell cholesterol is induced after 90 min of GnRH incubation and 17β-estradiol (E2) production is increased after 24, 48 and 72 h. These data indicate for the first time that GnRH regulates both cholesterol and steroid biosynthesis in human neuronal-like cells and suggest a new physiological role for GnRH in the brain.
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Affiliation(s)
- Fabiana Rosati
- Endocrine Unit, Department of Clinical Physiopathology, University of Florence, Viale G. Pieraccini 6, 50139 Firenze, Italy
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193
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Hamilton RT, Rettberg JR, Mao Z, To J, Zhao L, Appt SE, Register TC, Kaplan JR, Brinton RD. Hippocampal responsiveness to 17β-estradiol and equol after long-term ovariectomy: implication for a therapeutic window of opportunity. Brain Res 2011; 1379:11-22. [PMID: 21241683 PMCID: PMC3081673 DOI: 10.1016/j.brainres.2011.01.029] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2010] [Revised: 01/08/2011] [Accepted: 01/10/2011] [Indexed: 11/28/2022]
Abstract
A 'critical window of opportunity' has been proposed for the efficacy of ovarian hormone intervention in peri- and post-menopausal women. We sought to address this hypothesis using a long-term ovariectomized non-human primate (NHP) model, the cynomolgus macaque (Macaca fascicularis). In these studies, we assessed the ability of 17β-estradiol and equol to regulate markers of hippocampal bioenergetic capacity. Results indicated that 17β-estradiol treatment significantly increased expression of mitochondrial respiratory chain proteins complex-I and -III in the hippocampus when compared to non-hormone-treated animals. Expression of the TCA cycle protein succinate dehydrogenase α was decreased in animals treated with equol compared to those treated with 17β-estradiol. There were no significant effects of either 17β-estradiol or equol treatment on glycolytic protein expression in the hippocampus, nor were there significant effects of treatment on expression levels of antioxidant enzymes. Similarly, 17β-estradiol and equol treatment had no effect on mitochondrial fission and fusion protein expression. In summary, findings indicate that while 17β-estradiol induced a significant increase in several proteins, the overall profile of bioenergetic system proteins was neutral to slightly positively responsive. The profile of responses with the ERβ-preferring molecule equol was consistent with overall nonresponsiveness. Collectively, the data indicate that long-term ovariectomy is associated with a decline in response to estrogens and estrogen-like compounds. By extension, the data are consistent with a primary tenet of the critical window hypothesis, i.e., that the brains of post-menopausal women ultimately lose their ability to respond positively to estrogenic stimulation.
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Affiliation(s)
- Ryan T. Hamilton
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 90089
| | - Jamaica R. Rettberg
- Department of Neuroscience, University of Southern California, Los Angeles, CA 90089
| | - Zisu Mao
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 90089
| | - Jimmy To
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 90089
| | - Liqin Zhao
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 90089
| | - Susan E. Appt
- Department of Comparative Medicine, Wake Forest University, Winston-Salem, NC 27106
| | - Thomas C. Register
- Department of Comparative Medicine, Wake Forest University, Winston-Salem, NC 27106
| | - Jay R. Kaplan
- Department of Comparative Medicine, Wake Forest University, Winston-Salem, NC 27106
| | - Roberta Diaz Brinton
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 90089
- Department of Neuroscience, University of Southern California, Los Angeles, CA 90089
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194
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Yao J, Chen S, Cadenas E, Brinton RD. Estrogen protection against mitochondrial toxin-induced cell death in hippocampal neurons: antagonism by progesterone. Brain Res 2011; 1379:2-10. [PMID: 21134358 PMCID: PMC3200366 DOI: 10.1016/j.brainres.2010.11.090] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2010] [Revised: 11/06/2010] [Accepted: 11/29/2010] [Indexed: 02/06/2023]
Abstract
Previously we demonstrated that mitochondrial dysfunction plays a critical role in the pathogenesis of Alzheimer's disease. Further, we have shown that the neuroprotective effects of 17β-estradiol (E2) are dependent upon mitochondrial function. In the current study, we sought to identify mitochondrial sites of E2 action that mediate neuroprotection by assessing the efficacy of E2 to protect neurons against inhibitors of mitochondrial respiration which target specific complexes within the respiratory chain. Subsequently, the impact of progesterone (P4) on E2-induced prevention against mitochondrial toxins was investigated. Mitochondrial inhibitors, rotenone, 3-NPA, antimycin, KCN, and oligomycin, exhibited concentration dependent toxicity in primary hippocampal neurons. The concentration inducing 30% cell death (LD30) was selected for analyses assessing the neuroprotective efficacy of ovarian hormones (E2 and P4). Pretreatment of hippocampal neurons with E2 significantly protected against 3-NPA (7.5mM) and antimycin (125 μM) induced cell death and was moderately neuroprotective against rotenone (3 μM). E2 was ineffective against KCN and oligomycin-induced cell death. Pretreatment with P4 was without effect against these mitochondrial inhibitors. Co-administration of P4 with E2 abolished E2 induced neuroprotection against 3-NPA and antimycin. Additional metabolic analyses indicated that E2 and P4 separately increased mitochondrial respiratory capacity whereas the co-administration of E2 and P4 resulted in diminished mitochondrial respiration. These findings indicate that E2 protects against mitochondrial toxins that target complexes I, II and III whereas P4 was without effect. The data also predict that continuous combined co-administration of estrogen and progesterone common to many hormone therapy regimens is unlikely to prevent the deficits in mitochondrial function.
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Affiliation(s)
- Jia Yao
- Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 90033, USA
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195
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Irwin RW, Yao J, Ahmed SS, Hamilton RT, Cadenas E, Brinton RD. Medroxyprogesterone acetate antagonizes estrogen up-regulation of brain mitochondrial function. Endocrinology 2011; 152:556-67. [PMID: 21159850 PMCID: PMC3157324 DOI: 10.1210/en.2010-1061] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2010] [Accepted: 11/04/2010] [Indexed: 01/22/2023]
Abstract
The impact of clinical progestins used in contraception and hormone therapies on the metabolic capacity of the brain has long-term implications for neurological health in pre- and postmenopausal women. Previous analyses indicated that progesterone and 17β-estradiol (E2) sustain and enhance brain mitochondrial energy-transducing capacity. Herein we determined the impact of the clinical progestin, medroxyprogesterone acetate (MPA), on glycolysis, oxidative stress, and mitochondrial function in brain. Ovariectomized female rats were treated with MPA, E2, E2+MPA, or vehicle with ovary-intact rats serving as a positive control. MPA alone and MPA plus E2 resulted in diminished mitochondrial protein levels for pyruvate dehydrogenase, cytochrome oxidase, ATP synthase, manganese-superoxide dismutase, and peroxiredoxin V. MPA alone did not rescue the ovariectomy-induced decrease in mitochondrial bioenergetic function, whereas the coadministration of E2 and MPA exhibited moderate efficacy. However, the coadministration of MPA was detrimental to antioxidant defense, including manganese-superoxide dismutase activity/expression and peroxiredoxin V expression. Accumulated lipid peroxides were cleared by E2 treatment alone but not in combination with MPA. Furthermore, MPA abolished E2-induced enhancement of mitochondrial respiration in primary cultures of the hippocampal neurons and glia. Collectively these findings indicate that the effects of MPA differ significantly from the bioenergetic profile induced by progesterone and that, overall, MPA induced a decline in glycolytic and oxidative phosphorylation protein and activity. These preclinical findings on the basis of acute exposure to MPA raise concerns regarding neurological health after chronic use of MPA in contraceptive and hormone therapy.
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Affiliation(s)
- Ronald W Irwin
- Department of Pharmacology and Pharmaceutical Sciences, Pharmaceutical Sciences Center, University of Southern California, Los Angeles, California 90089, USA
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196
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Rettberg JR, Hamilton RT, Mao Z, To J, Zhao L, Appt SE, Register TC, Kaplan JR, Brinton RD. The effect of dietary soy isoflavones before and after ovariectomy on hippocampal protein markers of mitochondrial bioenergetics and antioxidant activity in female monkeys. Brain Res 2011; 1379:23-33. [PMID: 21238431 DOI: 10.1016/j.brainres.2011.01.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2010] [Revised: 01/06/2011] [Accepted: 01/07/2011] [Indexed: 12/20/2022]
Abstract
Estrogen therapy can promote cognitive function if initiated within a 'critical window' during the menopausal transition. However, in the absence of a progestogen, estrogens increase endometrial cancer risk which has spurred research into developing estrogenic alternatives that have the beneficial effects of estrogen but which are clinically safer. Soy protein is rich in isoflavones, which are a class of potential estrogenic alternatives. We sought to determine the effects of two diets, one with casein-lactalbumin as the main protein source and the other with soy protein containing isoflavones, on protein markers of hippocampal bioenergetic capacity in adult female cynomolgus macaques (Macaca fascicularis). Further, we assessed the effects of dietary soy isoflavones before or after ovariectomy. Animals receiving soy diet premenopausally then casein/lactalbumin post-ovariectomy had higher relative hippocampal content of glycolytic enzymes glyceraldehyde 3-phosphate dehydrogenase and pyruvate dehydrogenase subunit e1α. Post-ovariectomy consumption of soy was associated with higher succinate dehydrogenase α levels and lower levels of isocitrate dehydrogenase, both proteins involved in the tricarboxylic acid cycle, significantly decreased expression of the antioxidant enzyme peroxiredoxin-V, and a non-significant trend towards decreased manganese superoxide dismutase expression. None of the diet paradigms significantly affected expression levels of oxidative phosphorylation enzyme complexes, or of mitochondrial fission and fusion proteins. Together, these data suggest that long-term soy diet produces minimal effects on hippocampal expression of proteins involved in bioenergetics, but that switching between a diet containing primarily animal protein and one containing soy isoflavones before and after menopause may result in complex effects on brain chemistry.
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Affiliation(s)
- Jamaica R Rettberg
- Program in Neuroscience, University of Southern California, Los Angeles, CA 90089, USA
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197
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Srivastava DP, Penzes P. Rapid estradiol modulation of neuronal connectivity and its implications for disease. Front Endocrinol (Lausanne) 2011; 2:77. [PMID: 22654827 PMCID: PMC3356153 DOI: 10.3389/fendo.2011.00077] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2011] [Accepted: 11/04/2011] [Indexed: 12/05/2022] Open
Abstract
Estrogens have multiple actions in the brain including modulating synaptic plasticity, connectivity, and cognitive behaviors. While the classical view of estrogens are as endocrine signals, whose effects manifest via the regulation of gene transcription, mounting evidence has been presented demonstrating that estrogens have rapid effects within specific areas of the brain. The emergence that 17 β-estradiol can be produced locally in the brain which can elicit rapid (within minutes) cellular responses has led to its classification as a neurosteroid. Moreover, recent studies have also begun to detail the molecular and cellular underpinnings of how 17 β-estradiol can rapidly modulate spiny synapses (dendritic spines). Remodeling of dendritic spines is a key step in the rewiring of neuronal circuitry thought to underlie the processing and storage of information in the forebrain. Conversely, abnormal remodeling of dendritic spines is thought to contribute to a number of psychiatric and neurodevelopmental disorders. Here we review recent molecular and cellular work that offers a potential mechanism of how 17 β-estradiol may modulate synapse structure and function of cortical neurons. This mechanism allows cortical neurons to respond to activity-dependent stimuli with greater efficacy. In turn this form of plasticity may provide an insight into how 17 β-estradiol can modulate the rewiring of neuronal circuits, underlying its ability to influencing cortically based behaviors. We will then go on to discuss the potential role of 17 β-estradiol modulation of neural circuits and its potential relevance for the treatment of psychiatric and neurodevelopmental disorders.
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Affiliation(s)
- Deepak P. Srivastava
- Department of Physiology, Feinberg School of Medicine, Northwestern UniversityChicago, IL, USA
- Department of Neuroscience and Centre for the Cellular Basis of Behaviour, The James Black Centre, Institute of Psychiatry, King’s College LondonLondon, UK
- *Correspondence: Deepak P. Srivastava, Department of Physiology, Feinberg School of Medicine, Northwestern University, 303 E. Chicago Avenue, Chicago, IL 60611, USA. e-mail:
| | - Peter Penzes
- Department of Physiology, Feinberg School of Medicine, Northwestern UniversityChicago, IL, USA
- Department of Psychiatry and Behavioral Sciences, Feinberg School of Medicine, Northwestern UniversityChicago, IL, USA
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198
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Irwin RW, Wang JM, Chen S, Brinton RD. Neuroregenerative mechanisms of allopregnanolone in Alzheimer's disease. Front Endocrinol (Lausanne) 2011; 2:117. [PMID: 22654847 PMCID: PMC3356095 DOI: 10.3389/fendo.2011.00117] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2011] [Accepted: 12/27/2011] [Indexed: 11/25/2022] Open
Abstract
The proliferative pool and regenerative potential of neural stem cells diminishes with age, a phenomenon that may be exacerbated in prodromal and mild Alzheimer's disease (AD) brains. In parallel, the neuroactive progesterone metabolite, allopregnanolone (APα), along with a host of other factors, is decreased in the AD brain. Results of preclinical analyses demonstrate that APα is a potent inducer of neural progenitor proliferation of both rodent and human derived neural progenitor cells in vitro. In vivo, APα significantly increased neurogenesis within the subgranular zone of the dentate gyrus and subventricular zone of the 3xTgAD mouse model. Functionally, APα reversed the learning and memory deficits of 3xTgAD mice prior to and following the onset of AD pathology and was comparably efficacious in aged normal mice. In addition to inducing regenerative responses in mouse models of AD, APα significantly reduced beta-amyloid burden, beta-amyloid binding alcohol dehydrogenase load, and microglial activation. In parallel, APα increased markers of white matter generation and cholesterol homeostasis. Analyses to determine the optimal treatment regimen in the 3xTgAD mouse brain indicated that a treatment regimen of APα once per week was optimal for both inducing neurogenesis and reducing AD pathology. Pharmacokinetic analyses indicated that APα is rapidly increased in both plasma and brain following a single dose. APα is most efficacious when administered once per week which will contribute to its margin of safety. Further, analyses in both animals and humans have provided parameters for safe APα dosage exposure in humans. From a translational perspective, APα is a small molecular weight, blood brain barrier penetrant molecule with substantial preclinical efficacy data as a potential Alzheimer's therapeutic with existing safety data in animals and humans. To our knowledge, APα is the only small molecule that both promotes neural progenitor regeneration in brain and simultaneously reduces AD pathology burden.
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Affiliation(s)
- Ronald W. Irwin
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern CaliforniaLos Angeles, CA, USA
| | - Jun Ming Wang
- Department of Pathology, University of Mississippi Medical CenterJackson, MS, USA
| | - Shuhua Chen
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern CaliforniaLos Angeles, CA, USA
| | - Roberta Diaz Brinton
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern CaliforniaLos Angeles, CA, USA
- Department of Neurology, Keck School of Medicine, University of Southern CaliforniaLos Angeles, CA, USA
- *Correspondence: Roberta Diaz Brinton, Department of Pharmacology and Pharmaceutical Sciences, Pharmaceutical Sciences Center, University of Southern California, 1985 Zonal Avenue, Los Angeles, CA 90089-9121, USA. e-mail:
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199
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Liu L, Zhao L, She H, Chen S, Wang JM, Wong C, McClure K, Sitruk-Ware R, Brinton RD. Clinically relevant progestins regulate neurogenic and neuroprotective responses in vitro and in vivo. Endocrinology 2010; 151:5782-94. [PMID: 20943809 PMCID: PMC2999493 DOI: 10.1210/en.2010-0005] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Previously, we demonstrated that progesterone (P(4)) promoted adult rat neural progenitor cell (rNPC) proliferation with concomitant regulation of cell-cycle gene expression via the P(4) receptor membrane component/ERK pathway. Here, we report the efficacy of seven clinically relevant progestins alone or in combination with 17β-estradiol (E(2)) on adult rNPC proliferation and hippocampal cell viability in vitro and in vivo. In vitro analyses indicated that P(4), norgestimate, Nestorone, norethynodrel, norethindrone, and levonorgestrel (LNG) significantly increased in rNPC proliferation, whereas norethindrone acetate was without effect, and medroxyprogesterone acetate (MPA) inhibited rNPC proliferation. Proliferative progestins in vitro were also neuroprotective. Acute in vivo exposure to P(4) and Nestorone significantly increased proliferating cell nuclear antigen and cell division cycle 2 expression and total number of hippocampal 5-bromo-2-deoxyuridine (BrdU)-positive cells, whereas LNG and MPA were without effect. Mechanistically, neurogenic progestins required activation of MAPK to promote proliferation. P(4), Nestorone, and LNG significantly increased ATP synthase subunit α (complex V, subunit α) expression, whereas MPA was without effect. In combination with E(2), P(4), Nestorone, LNG, and MPA significantly increased BrdU incorporation. However, BrdU incorporation induced by E(2) plus LNG or MPA was paralleled by a significant increase in apoptosis. A rise in Bax/Bcl-2 ratio paralleled apoptosis induced by LNG and MPA. With the exception of P(4), clinical progestins antagonized E(2)-induced rise in complex V, subunit α. These preclinical translational findings indicate that the neurogenic response to clinical progestins varies dramatically. Progestin impact on the regenerative capacity of the brain has clinical implications for contraceptive and hormone therapy formulations prescribed for pre- and postmenopausal women.
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Affiliation(s)
- Lifei Liu
- Program in Neuroscience, University of Southern California, School of Pharmacy Pharmaceutical Sciences Center, Los Angeles, California 90033, USA
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200
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Synaptic estrogen receptor-alpha levels in prefrontal cortex in female rhesus monkeys and their correlation with cognitive performance. J Neurosci 2010; 30:12770-6. [PMID: 20861381 DOI: 10.1523/jneurosci.3192-10.2010] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
In rat hippocampus, estrogen receptor-α (ER-α) can initiate nongenomic signaling mechanisms that modulate synaptic plasticity in response to either circulating or locally synthesized estradiol (E). Here we report quantitative electron microscopic data demonstrating that ER-α is present within excitatory synapses in dorsolateral prefrontal cortex (dlPFC) of young and aged ovariectomized female rhesus monkeys with and without E treatment. There were no treatment or age effects on the percentage of excitatory synapses containing ER-α, nor were there any group differences in distribution of ER-α within the synapse. However, the mean size of synapses containing ER-α was larger than that of unlabeled excitatory synapses. All monkeys were tested on delayed response (DR), a cognitive test of working memory that requires dlPFC. In young ovariectomized monkeys without E treatment, presynaptic ER-α correlated with DR accuracy across memory delays. In aged monkeys that received E treatment, ER-α within the postsynaptic density (30-60 nm from the synaptic membrane) positively correlated with DR performance. Thus, although the lack of group effects suggests that ER-α is primarily in synapses that are stable across age and treatment, synaptic abundance of ER-α is correlated with individual performance in two key age/treatment groups. These data have important implications for individual differences in the cognitive outcome among menopausal women and promote a focus on cortical estrogen receptors for therapeutic efficacy with respect to cognition.
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