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Bellingacci L, Canonichesi J, Sciaccaluga M, Megaro A, Mazzocchetti P, Di Mauro M, Costa C, Di Filippo M, Pettorossi VE, Tozzi A. Locally Synthetized 17-β-Estradiol Reverses Amyloid-β-42-Induced Hippocampal Long-Term Potentiation Deficits. Int J Mol Sci 2024; 25:1377. [PMID: 38338656 PMCID: PMC10855267 DOI: 10.3390/ijms25031377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2024] [Revised: 01/19/2024] [Accepted: 01/20/2024] [Indexed: 02/12/2024] Open
Abstract
Amyloid beta 1-42 (Aβ42) aggregates acutely impair hippocampal long-term potentiation (LTP) of synaptic transmission, and 17β-estradiol is crucial for hippocampal LTP. We tested whether boosting the synthesis of neural-derived 17β-estradiol (nE2) saves hippocampal LTP by the neurotoxic action of Aβ42. Electrophysiological recordings were performed to measure dentate gyrus (DG) LTP in rat hippocampal slices. Using a pharmacological approach, we tested the ability of nE2 to counteract the LTP impairment caused by acute exposure to soluble Aβ42 aggregates. nE2 was found to be required for LTP in DG under physiological conditions. Blockade of steroid 5α-reductase with finasteride, by increasing nE2 synthesis from testosterone (T), completely recovered LTP in slices treated with soluble Aβ42 aggregates. Modulation of the glutamate N-methyl-D aspartate receptor (NMDAR) by memantine effectively rescued the LTP deficit observed in slices exposed to Aβ42, and memantine prevented LTP reduction observed under the blocking of nE2 synthesis. nE2 is able to counteract Aβ42-induced synaptic dysfunction. This effect depends on a rapid, non-genomic mechanism of action of nE2, which may share a common pathway with glutamate NMDAR signaling.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Alessandro Tozzi
- Department of Medicine and Surgery, University of Perugia, 06156 Perugia, Italy; (L.B.); (J.C.); (M.S.)
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2
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Lewitus VJ, Blackwell KT. Estradiol Receptors Inhibit Long-Term Potentiation in the Dorsomedial Striatum. eNeuro 2023; 10:ENEURO.0071-23.2023. [PMID: 37487741 PMCID: PMC10405883 DOI: 10.1523/eneuro.0071-23.2023] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 05/25/2023] [Accepted: 06/19/2023] [Indexed: 07/26/2023] Open
Abstract
Estradiol, a female sex hormone and the predominant form of estrogen, has diverse effects throughout the brain including in learning and memory. Estradiol modulates several types of learning that depend on the dorsomedial striatum (DMS), a subregion of the basal ganglia involved in goal-directed learning, cued action-selection, and motor skills. A cellular basis of learning is synaptic plasticity, and the presence of extranuclear estradiol receptors ERα, ERβ, and G-protein-coupled estrogen receptor (GPER) throughout the DMS suggests that estradiol may influence rapid cellular actions including those involved in plasticity. To test whether estradiol affects synaptic plasticity in the DMS, corticostriatal long-term potentiation (LTP) was induced using theta-burst stimulation (TBS) in ex vivo brain slices from intact male and female C57BL/6 mice. Extracellular field recordings showed that female mice in the diestrous stage of the estrous cycle exhibited LTP similar to male mice, while female mice in estrus did not exhibit LTP. Furthermore, antagonists of ERα or GPER rescued LTP in estrous females and agonists of ERα or GPER reduced LTP in diestrous females. In males, activating ERα but not GPER reduced LTP. These results uncover an inhibitory action of estradiol receptors on cellular learning in the DMS and suggest a cellular mechanism underlying the impairment in certain types of DMS-based learning observed in the presence of high estradiol. Because of the dorsal striatum's role in substance use disorders, these findings may provide a mechanism underlying an estradiol-mediated progression from goal-directed to habitual drug use.
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Affiliation(s)
| | - Kim T Blackwell
- Interdisciplinary Neuroscience PhD Program
- Department of Bioengineering, George Mason University, Fairfax, VA 22030
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3
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Wang J, Pratap UP, Lu Y, Sareddy GR, Tekmal RR, Vadlamudi RK, Brann DW. Development and Characterization of Inducible Astrocyte-Specific Aromatase Knockout Mice. BIOLOGY 2023; 12:621. [PMID: 37106821 PMCID: PMC10135694 DOI: 10.3390/biology12040621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 04/04/2023] [Accepted: 04/14/2023] [Indexed: 04/29/2023]
Abstract
17β-estradiol (E2) is produced in the brain as a neurosteroid, in addition to being an endocrine signal in the periphery. The current animal models for studying brain-derived E2 include global and conditional non-inducible knockout mouse models. The aim of this study was to develop a tamoxifen (TMX)-inducible astrocyte-specific aromatase knockout mouse line (GFAP-ARO-iKO mice) to specifically deplete the E2 synthesis enzymes and aromatase in astrocytes after their development in adult mice. The characterization of the GFAP-ARO-iKO mice revealed a specific and robust depletion in the aromatase expressions of their astrocytes and a significant decrease in their hippocampal E2 levels after a GCI. The GFAP-ARO-iKO animals were alive and fertile and had a normal general brain anatomy, with a normal astrocyte shape, intensity, and distribution. In the hippocampus, after a GCI, the GFAP-ARO-iKO animals showed a major deficiency in their reactive astrogliosis, a dramatically increased neuronal loss, and increased microglial activation. These findings indicate that astrocyte-derived E2 (ADE2) regulates the ischemic induction of reactive astrogliosis and microglial activation and is neuroprotective in the ischemic brain. The GFAP-ARO-iKO mouse models thus provide an important new model to help elucidate the roles and functions of ADE2 in the brain.
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Affiliation(s)
- Jing Wang
- Department of Neurosurgery, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Uday P. Pratap
- Department of Obstetrics and Gynecology, University of Texas Health, San Antonio, TX 78229, USA
| | - Yujiao Lu
- Department of Neurosurgery, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Gangadhara R. Sareddy
- Department of Obstetrics and Gynecology, University of Texas Health, San Antonio, TX 78229, USA
| | - Rajeshwar R. Tekmal
- Department of Obstetrics and Gynecology, University of Texas Health, San Antonio, TX 78229, USA
| | - Ratna K. Vadlamudi
- Department of Obstetrics and Gynecology, University of Texas Health, San Antonio, TX 78229, USA
| | - Darrell W. Brann
- Department of Neurosurgery, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
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4
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G-protein coupled estrogen receptor (GPER1) activation promotes synaptic insertion of AMPA receptors and induction of chemical LTP at hippocampal temporoammonic-CA1 synapses. Mol Brain 2023; 16:16. [PMID: 36709268 PMCID: PMC9883958 DOI: 10.1186/s13041-023-01003-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Accepted: 01/12/2023] [Indexed: 01/30/2023] Open
Abstract
It is well documented that 17β estradiol (E2) regulates excitatory synaptic transmission at hippocampal Shaffer-collateral (SC)-CA1 synapses, via activation of the classical estrogen receptors (ERα and ERβ). Hippocampal CA1 pyramidal neurons are also innervated by the temporoammonic (TA) pathway, and excitatory TA-CA1 synapses are reported to be regulated by E2. Recent studies suggest a role for the novel G-protein coupled estrogen receptor (GPER1) at SC-CA1 synapses, however, the role of GPER1 in mediating the effects of E2 at juvenile TA-CA1 synapses is unclear. Here we demonstrate that the GPER1 agonist, G1 induces a persistent, concentration-dependent (1-10 nM) increase in excitatory synaptic transmission at TA-CA1 synapses and this effect is blocked by selective GPER1 antagonists. The ability of GPER1 to induce this novel form of chemical long-term potentiation (cLTP) was prevented following blockade of N-methyl-D-aspartate (NMDA) receptors, and it was not accompanied by any change in paired pulse facilitation ratio (PPR). GPER1-induced cLTP involved activation of ERK but was independent of phosphoinositide 3-kinase (PI3K) signalling. Prior treatment with philanthotoxin prevented the effects of G1, indicating that synaptic insertion of GluA2-lacking α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors underlies GPER1-induced cLTP. Furthermore, activity-dependent LTP occluded G1-induced cLTP and vice versa, indicating that these processes have overlapping expression mechanisms. Activity-dependent LTP was blocked by the GPER1 antagonist, G15, suggesting that GPER1 plays a role in NMDA-dependent LTP at juvenile TA-CA1 synapses. These findings add a new dimension to our understanding of GPER1 in modulating neuronal plasticity with relevance to age-related neurodegenerative conditions.
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5
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Fainanta T, Jaroenporn S, Wititsuwankul P, Malaivijitnond S. Comparison of neuroprotective effects of dihydrotestosterone, 17β-estradiol, and Pueraria mirifica herb extract on cognitive impairment in androgen deficient male rats. Horm Behav 2022; 143:105198. [PMID: 35609404 DOI: 10.1016/j.yhbeh.2022.105198] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 05/06/2022] [Accepted: 05/08/2022] [Indexed: 01/30/2023]
Abstract
This study investigated the neuroprotective effects of dihydrotestosterone (DHT), 17β-estradiol (E2), and Pueraria mirifica herb extract (PME; an alternative source of natural estrogens) on the (i) learning and memory in androgen-deficient male rats, and on the hippocampus expression levels of (ii) mRNA of genes associated with synaptic transmission and structure, neurofibrillary tangles, and amyloid plaques, and (iii) total and phosphorylated tau proteins. The four-month-old male rats were sham-operated or orchidectomized (ODX). The ODX rats were divided into four groups, and orally treated for 2 months with either 1 mL/d of distilled water or 100 mg/kg/d of PME; or subcutaneously injected with 1 mg/kg/d of DHT or 80 μg/kg/d of E2. The impairment of spatial learning behavior and memory capacity in the ODX rats was prevented by DHT, E2, and PME. Recovery of the orchidectomy-induced deterioration of the synaptic plasticity in the hippocampus of rats was ranked as E2 ≥ PME > DHT. Both DHT and PME mitigated the increased Tau3 and Tau4 mRNA levels, and Tau-5 and P-Tau Ser396 protein levels more than E2 (DHT ≥ PME > E2). Only DHT tended to decrease App mRNA expression level. In conclusion, DHT showed a stronger efficacy for mitigation of the impaired spatial learning behavior and memory capacity in androgen-deficient male rats compared to E2 and PME, and their mechanisms of action are slightly different.
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Affiliation(s)
- Taratorn Fainanta
- Biological Sciences Program, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand; Department of Biology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
| | - Sukanya Jaroenporn
- Department of Biology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand.
| | - Patteera Wititsuwankul
- Department of Biology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
| | - Suchinda Malaivijitnond
- Department of Biology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand.
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6
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Chen H, Zhang X, Xu C, An S, Ma XM, Qiao H. Endogenous Hippocampal Estrogen Is Involved in Stress-induced Depression-like Behaviors and Spine Plasticity in Male Rats. Neurosci Lett 2022; 785:136560. [DOI: 10.1016/j.neulet.2022.136560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 01/20/2022] [Accepted: 02/25/2022] [Indexed: 10/19/2022]
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7
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Perez-Rando M, Guirado R, Tellez-Merlo G, Carceller H, Nacher J. Estradiol Regulates Polysialylated Form of the Neural Cell Adhesion Molecule Expression and Connectivity of O-LM Interneurons in the Hippocampus of Adult Female Mice. Neuroendocrinology 2022; 112:51-67. [PMID: 33550289 DOI: 10.1159/000515052] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Accepted: 02/04/2021] [Indexed: 11/19/2022]
Abstract
The estrous cycle is caused by the changing concentration of ovarian hormones, particularly 17β-estradiol, a hormone whose effect on excitatory circuits has been extensively reported. However, fewer studies have tried to elucidate how this cycle, or this hormone, affects the plasticity of inhibitory networks and the structure of interneurons. Among these cells, somatostatin-expressing O-LM neurons of the hippocampus are especially interesting. They have a role in the modulation of theta oscillations, and they receive direct input from the entorhinal cortex, which place them in the center of hippocampal function. In this study, we report that the expression of polysialylated form of the neural cell adhesion molecule (PSA-NCAM) in the hippocampus, a molecule involved in the plasticity of somatostatin-expressing interneurons in the adult brain, fluctuated through the different stages of the estrous cycle. Likewise, these stages and the expression of PSA-NCAM affected the density of dendritic spines of O-LM cells. We also describe that 17β-estradiol replacement of adult ovariectomized female mice caused an increase in the perisomatic inhibitory puncta in O-LM interneurons as well as an increase in their axonal bouton density. Interestingly, this treatment also induced a decrease in their dendritic spine density, specifically in O-LM interneurons lacking PSA-NCAM expression. Finally, using an ex vivo real-time assay with entorhinal-hippocampal organotypic cultures, we show that this hormone decreased the dynamics in spinogenesis, altogether highlighting the modulatory effect that 17β-estradiol has on inhibitory circuits.
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Affiliation(s)
- Marta Perez-Rando
- Neurobiology Unit, Program in Neurosciences and BIOTECMED Institute, Universitat de València, Burjassot, Spain
- Fundación Investigación Hospital Clínico de Valencia, INCLIVA, Valencia, Spain
| | - Ramon Guirado
- Neurobiology Unit, Program in Neurosciences and BIOTECMED Institute, Universitat de València, Burjassot, Spain
- Fundación Investigación Hospital Clínico de Valencia, INCLIVA, Valencia, Spain
- Dirección General de Universidades, Gobierno de Aragón, Zaragoza, Spain
| | - Guillermina Tellez-Merlo
- Lab. Neuropsiquiatría, Instituto de Fisiología, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
- Departamento de Fisiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Ciudad de México, Mexico
| | - Hector Carceller
- Neurobiology Unit, Program in Neurosciences and BIOTECMED Institute, Universitat de València, Burjassot, Spain
| | - Juan Nacher
- Neurobiology Unit, Program in Neurosciences and BIOTECMED Institute, Universitat de València, Burjassot, Spain
- Fundación Investigación Hospital Clínico de Valencia, INCLIVA, Valencia, Spain
- CIBERSAM: Spanish National Network for Research in Mental Health, Valencia, Spain
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8
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Brann DW, Lu Y, Wang J, Sareddy GR, Pratap UP, Zhang Q, Tekmal RR, Vadlamudi RK. Neuron-Derived Estrogen-A Key Neuromodulator in Synaptic Function and Memory. Int J Mol Sci 2021; 22:ijms222413242. [PMID: 34948039 PMCID: PMC8706511 DOI: 10.3390/ijms222413242] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 11/29/2021] [Accepted: 12/04/2021] [Indexed: 01/31/2023] Open
Abstract
In addition to being a steroid hormone, 17β-estradiol (E2) is also a neurosteroid produced in neurons in various regions of the brain of many species, including humans. Neuron-derived E2 (NDE2) is synthesized from androgen precursors via the action of the biosynthetic enzyme aromatase, which is located at synapses and in presynaptic terminals in neurons in both the male and female brain. In this review, we discuss evidence supporting a key role for NDE2 as a neuromodulator that regulates synaptic plasticity and memory. Evidence supporting an important neuromodulatory role of NDE2 in the brain has come from studies using aromatase inhibitors, aromatase overexpression in neurons, global aromatase knockout mice, and the recent development of conditional forebrain neuron-specific knockout mice. Collectively, these studies demonstrate a key role of NDE2 in the regulation of synapse and spine density, efficacy of excitatory synaptic transmission and long-term potentiation, and regulation of hippocampal-dependent recognition memory, spatial reference memory, and contextual fear memory. NDE2 is suggested to achieve these effects through estrogen receptor-mediated regulation of rapid kinase signaling and CREB-BDNF signaling pathways, which regulate actin remodeling, as well as transcription, translation, and transport of synaptic proteins critical for synaptic plasticity and function.
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Affiliation(s)
- Darrell W. Brann
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA;
- Correspondence:
| | - Yujiao Lu
- Department of Neurosurgery, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA;
| | - Jing Wang
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA;
| | - Gangadhara R. Sareddy
- Department of Obstetrics and Gynecology, University of Texas Health, San Antonio, TX 78229, USA; (G.R.S.); (U.P.P.); (R.R.T.); (R.K.V.)
| | - Uday P. Pratap
- Department of Obstetrics and Gynecology, University of Texas Health, San Antonio, TX 78229, USA; (G.R.S.); (U.P.P.); (R.R.T.); (R.K.V.)
| | - Quanguang Zhang
- Department of Neurology, Louisiana State University Health, Shreveport, LA 71103, USA;
| | - Rajeshwar R. Tekmal
- Department of Obstetrics and Gynecology, University of Texas Health, San Antonio, TX 78229, USA; (G.R.S.); (U.P.P.); (R.R.T.); (R.K.V.)
| | - Ratna K. Vadlamudi
- Department of Obstetrics and Gynecology, University of Texas Health, San Antonio, TX 78229, USA; (G.R.S.); (U.P.P.); (R.R.T.); (R.K.V.)
- Audie L. Murphy Division, South Texas Veterans Health Care System, San Antonio, TX 78229, USA
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9
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Brann DW, Lu Y, Wang J, Zhang Q, Thakkar R, Sareddy GR, Pratap UP, Tekmal RR, Vadlamudi RK. Brain-derived estrogen and neural function. Neurosci Biobehav Rev 2021; 132:793-817. [PMID: 34823913 PMCID: PMC8816863 DOI: 10.1016/j.neubiorev.2021.11.014] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 10/26/2021] [Accepted: 11/12/2021] [Indexed: 01/02/2023]
Abstract
Although classically known as an endocrine signal produced by the ovary, 17β-estradiol (E2) is also a neurosteroid produced in neurons and astrocytes in the brain of many different species. In this review, we provide a comprehensive overview of the localization, regulation, sex differences, and physiological/pathological roles of brain-derived E2 (BDE2). Much of what we know regarding the functional roles of BDE2 has come from studies using specific inhibitors of the E2 synthesis enzyme, aromatase, as well as the recent development of conditional forebrain neuron-specific and astrocyte-specific aromatase knockout mouse models. The evidence from these studies support a critical role for neuron-derived E2 (NDE2) in the regulation of synaptic plasticity, memory, socio-sexual behavior, sexual differentiation, reproduction, injury-induced reactive gliosis, and neuroprotection. Furthermore, we review evidence that astrocyte-derived E2 (ADE2) is induced following brain injury/ischemia, and plays a key role in reactive gliosis, neuroprotection, and cognitive preservation. Finally, we conclude by discussing the key controversies and challenges in this area, as well as potential future directions for the field.
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Affiliation(s)
- Darrell W Brann
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA, 30912, USA.
| | - Yujiao Lu
- Department of Neurosurgery, Medical College of Georgia, Augusta University, Augusta, GA, 30912, USA
| | - Jing Wang
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA, 30912, USA
| | - Quanguang Zhang
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA, 30912, USA
| | - Roshni Thakkar
- Department of Neurology, Miller School of Medicine, University of Miami, Miami, FL, 33136, USA
| | - Gangadhara R Sareddy
- Department of Obstetrics and Gynecology, University of Texas Health, San Antoio TX, 78229, USA
| | - Uday P Pratap
- Department of Obstetrics and Gynecology, University of Texas Health, San Antoio TX, 78229, USA
| | - Rajeshwar R Tekmal
- Department of Obstetrics and Gynecology, University of Texas Health, San Antoio TX, 78229, USA
| | - Ratna K Vadlamudi
- Department of Obstetrics and Gynecology, University of Texas Health, San Antoio TX, 78229, USA; Audie L. Murphy Division, South Texas Veterans Health Care System, San Antonio, TX, 78229, USA.
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10
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Soutar CN, Grenier P, Patel A, Kabitsis PP, Olmstead MC, Bailey CDC, Dringenberg HC. Brain-Generated 17β-Estradiol Modulates Long-Term Synaptic Plasticity in the Primary Auditory Cortex of Adult Male Rats. Cereb Cortex 2021; 32:2140-2155. [PMID: 34628498 DOI: 10.1093/cercor/bhab345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Neuron-derived 17β-estradiol (E2) alters synaptic transmission and plasticity in brain regions with endocrine and non-endocrine functions. Investigations into a modulatory role of E2 in synaptic activity and plasticity have mainly focused on the rodent hippocampal formation. In songbirds, E2 is synthesized by auditory forebrain neurons and promotes auditory signal processing and memory for salient acoustic stimuli; however, the modulatory effects of E2 on memory-related synaptic plasticity mechanisms have not been directly examined in the auditory forebrain. We investigated the effects of bidirectional E2 manipulations on synaptic transmission and long-term potentiation (LTP) in the rat primary auditory cortex (A1). Immunohistochemistry revealed widespread neuronal expression of the E2 biosynthetic enzyme aromatase in multiple regions of the rat sensory and association neocortex, including A1. In A1, E2 application reduced the threshold for in vivo LTP induction at layer IV synapses, whereas pharmacological suppression of E2 production by aromatase inhibition abolished LTP induction at layer II/III synapses. In acute A1 slices, glutamate and γ-aminobutyric acid (GABA) receptor-mediated currents were sensitive to E2 manipulations in a layer-specific manner. These findings demonstrate that locally synthesized E2 modulates synaptic transmission and plasticity in A1 and suggest potential mechanisms by which E2 contributes to auditory signal processing and memory.
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Affiliation(s)
- Chloe N Soutar
- Centre for Neuroscience Studies, Queen's University, Kingston, Ontario K7L 3N6, Canada
| | - Patrick Grenier
- Department of Psychology, Queen's University, Kingston, Ontario K7L 3N6, Canada
| | - Ashutosh Patel
- Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Pauline P Kabitsis
- Department of Psychology, Queen's University, Kingston, Ontario K7L 3N6, Canada
| | - Mary C Olmstead
- Centre for Neuroscience Studies, Queen's University, Kingston, Ontario K7L 3N6, Canada.,Department of Psychology, Queen's University, Kingston, Ontario K7L 3N6, Canada
| | - Craig D C Bailey
- Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Hans C Dringenberg
- Centre for Neuroscience Studies, Queen's University, Kingston, Ontario K7L 3N6, Canada.,Department of Psychology, Queen's University, Kingston, Ontario K7L 3N6, Canada
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11
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Li X, Johann S, Rune GM, Bender RA. Sex-specific Regulation of Spine Density and Synaptic Proteins by G-protein-coupled Estrogen Receptor (GPER)1 in Developing Hippocampus. Neuroscience 2021; 472:35-50. [PMID: 34364953 DOI: 10.1016/j.neuroscience.2021.07.035] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Revised: 07/28/2021] [Accepted: 07/29/2021] [Indexed: 11/19/2022]
Abstract
G-protein-coupled-estrogen-receptor 1 (GPER1) is a membrane-bound receptor that mediates estrogen signaling via intracellular signaling cascades. We recently showed that GPER1 promotes the distal dendritic enrichment of hyperpolarization activated and cyclic nucleotide-gated (HCN)1 channels in CA1 stratum lacunosum-moleculare (SLM), suggesting a role of GPER1-mediated signaling in neuronal plasticity. Here we studied whether this role involves processes of structural plasticity, such as the regulation of spine and synapse density in SLM. In organotypic entorhino-hippocampal cultures from mice expressing eGFP, we analyzed spine densities in SLM after treatment with GPER1 agonist G1 (20 nM). G1 significantly increased the density of "non-stubby" spines (maturing spines with a spine head and a neck), but did so only in cultures from female mice. In support of this finding, the expression of synaptic proteins was sex-specifically altered in the cultures: G1 increased the protein (but not mRNA) expression of PSD95 and reduced the p-/n-cofilin ratio only in cultures from females. Application of E2 (2 nM) reproduced the sex-specific effect on spine density in SLM, but only partially on the expression of synaptic proteins. Spine synapse density was, however, not altered after G1-treatment, suggesting that the increased spine density did not translate into an increased spine synapse density in the culture model. Taken together, our results support a role of GPER1 in mediating structural plasticity in CA1 SLM, but suggest that in developing hippocampus, this role is sex-specific.
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Affiliation(s)
- Xiaoyu Li
- Institute of Neuroanatomy, University Medical Center Hamburg, 20246 Hamburg, Germany
| | - Sonja Johann
- Institute of Neuroanatomy, University Medical Center Hamburg, 20246 Hamburg, Germany
| | - Gabriele M Rune
- Institute of Neuroanatomy, University Medical Center Hamburg, 20246 Hamburg, Germany
| | - Roland A Bender
- Institute of Neuroanatomy, University Medical Center Hamburg, 20246 Hamburg, Germany.
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12
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Lan Z, Meng Z, Lian B, Liu M, Sun T, Sun H, Liu Z, Hu Z, Guo Q, Zhang J. Hippocampal Aromatase Knockdown Aggravates Ovariectomy-Induced Spatial Memory Impairment, Aβ Accumulation and Neural Plasticity Deficiency in Adult Female Mice. Neurochem Res 2021; 46:1188-1202. [PMID: 33559105 DOI: 10.1007/s11064-021-03258-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 01/12/2021] [Accepted: 01/22/2021] [Indexed: 12/23/2022]
Abstract
Ovarian estrogens (mainly 17β estradiol, E2) have been involved in the regulation of the structure of hippocampus, the center of spatial memory. In recent years, high levels of aromatase (AROM), the estrogen synthase, has been localized in hippocampus; and this hippocampus-derived E2 seems to be functional in synaptic plasticity and spatial memory as ovarian E2 does. However, the contribution of ovarian E2 and hippocampal E2 to spatial memory and neural plasticity remains unclear. In this study, AROM-specific RNA interference AAVs (shAROM) were constructed and injected into the hippocampus of control or ovariectomized (OVX) mice. Four weeks later the spatial learning and memory behavior was examined with Morris water maze, the expression of hippocampal Aβ related proteins, selected synaptic proteins and CA1 synapse density, actin polymerization related proteins and CA1 spine density were also examined. The results showed that while OVX and hippocampal shAROM contributed similarly to most of the parameters examined, shAROM induced more increase in BACE1 (amyloidogenic β-secretase), more decrease in neprilysin (Aβ remover) and Profilin-1 (actin polymerization inducer). More importantly, combined OVX and shAROM treatment displayed most significant impairment of spatial learning and memory as well as decrease in synaptic plasticity compared to OVX or shAROM alone. In conclusion, the above results clearly demonstrated the crucial role of hippocampal E2 in the regulation of the structure and function of hippocampus besides ovarian E2, indicating that hippocampal E2 content should also be taken into consideration during estrogenic replacement.
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Affiliation(s)
- Zhen Lan
- Department of Neurobiology, Army Medical University, Chongqing, China
| | - Zhaoyou Meng
- Department of Neurobiology, Army Medical University, Chongqing, China
| | - Biyao Lian
- Department of Neurobiology, Army Medical University, Chongqing, China
- Department of Pediatrics, the Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Mengying Liu
- Department of Neurobiology, Army Medical University, Chongqing, China
- The 305 Hospital of PLA, Beijing, China
| | - Tao Sun
- Department of Neurobiology, Army Medical University, Chongqing, China
- The 63650 Hospital of PLA, Malan, China
| | - Huan Sun
- Department of Neurobiology, Army Medical University, Chongqing, China
- Center for Brain Science, the First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Zhi Liu
- Department of Histology and Embryology, Army Medical University, Chongqing, China
| | - Zhenxin Hu
- Battalion One of Basic Medical Sciences, Army Medical University, Chongqing, China
| | - Qiang Guo
- Department of Basic Medicine, Chongqing Medical and Pharmaceutical College, Chongqing, China.
| | - Jiqiang Zhang
- Department of Neurobiology, Army Medical University, Chongqing, China.
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13
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Yang Q, Zhang Y, Zhang L, Li X, Dong R, Song C, Cheng L, Shi M, Zhao H. Combination of tea polyphenols and proanthocyanidins prevents menopause-related memory decline in rats via increased hippocampal synaptic plasticity by inhibiting p38 MAPK and TNF-α pathway. Nutr Neurosci 2021; 25:1909-1927. [PMID: 33871312 DOI: 10.1080/1028415x.2021.1913929] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
OBJECTIVE Many studies have examined the beneficial effects of tea polyphenols (TP) and proanthocyanidins (PC) on the memory impairment in different animal models. However, the combined effects of them on synaptic, memory dysfunction and molecular mechanisms have been poorly studied, especially in the menopause-related memory decline in rats. METHODS In this rat study, TP and PC were used to investigate their protective effects on memory decline caused by inflammation. We characterized the learning and memory abilities, synaptic plasticity, AMPAR, phosphorylation of the p38 protein, TNF-ɑ, structural synaptic plasticity-related indicators in the hippocampus. RESULTS The results showed that deficits of learning and memory in OVX + D-gal rats, which was accompanied by dendrites and synaptic morphology damage, and increased expression of Aβ1-42 and inflammation. The beneficial effects of TP and PC treatment were found to prevent memory loss and significantly improve synaptic structure and functional plasticity. TP+PC combination shows more obvious advantages than intervention alone. TP and PC treatment improved behavioral performance, the hippocampal LTP damage and the shape and number of dendrites, dendritic spines and synapses, reduced the burden of Aβ and decreased the inflammation in hippocampus. In addition, TP and PC treatment decreased the expressions of Iba-1, TNF-α, TNFR1, and TRAF2. CONCLUSIONS These results provided a novel evidence TP combined with PC inhibits p38 MAPK pathway, suppresses the inflammation in hippocampus, and increase the externalization of AMPAR, which may be one of the mechanisms to improve synaptic plasticity and memory in the menopause-related memory decline rats.
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Affiliation(s)
- Qian Yang
- Department of Nutrition and Food Hygiene, School of Public Health, Shanxi Medical University, Taiyuan, People's Republic of China
| | - Yusen Zhang
- Department of Nutrition and Food Hygiene, School of Public Health, Shanxi Medical University, Taiyuan, People's Republic of China
| | - Luping Zhang
- Department of Nutrition and Food Hygiene, School of Public Health, Shanxi Medical University, Taiyuan, People's Republic of China
| | - Xuemin Li
- Center for Disease Control and Prevention in Shanxi Province, Taiyuan, People's Republic of China
| | - Ruirui Dong
- Department of Nutrition and Food Hygiene, School of Public Health, Shanxi Medical University, Taiyuan, People's Republic of China
| | - Chenmeng Song
- Department of Nutrition and Food Hygiene, School of Public Health, Shanxi Medical University, Taiyuan, People's Republic of China
| | - Le Cheng
- Department of Nutrition and Food Hygiene, School of Public Health, Shanxi Medical University, Taiyuan, People's Republic of China
| | - Mengqian Shi
- Department of Nutrition and Food Hygiene, School of Public Health, Shanxi Medical University, Taiyuan, People's Republic of China
| | - Haifeng Zhao
- Department of Nutrition and Food Hygiene, School of Public Health, Shanxi Medical University, Taiyuan, People's Republic of China
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14
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Cao T, Tang M, Jiang P, Zhang B, Wu X, Chen Q, Zeng C, Li N, Zhang S, Cai H. A Potential Mechanism Underlying the Therapeutic Effects of Progesterone and Allopregnanolone on Ketamine-Induced Cognitive Deficits. Front Pharmacol 2021; 12:612083. [PMID: 33767621 PMCID: PMC7985688 DOI: 10.3389/fphar.2021.612083] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 01/29/2021] [Indexed: 11/13/2022] Open
Abstract
Ketamine exposure can model cognitive deficits associated with schizophrenia. Progesterone (PROG) and its active metabolite allopregnanolone (ALLO) have neuroprotective effects and the pathway involving progesterone receptor membrane component 1 (PGRMC1), epidermal growth factor receptor (EGFR), glucagon-like peptide-1 receptor (GLP-1R), phosphatidylinositol 3 kinase (PI3K), and protein kinase B (Akt) appears to play a key role in their neuroprotection. The present study aimed to investigate the effects of PROG (8,16 mg kg−1) and ALLO (8,16 mg kg−1) on the reversal of cognitive deficits induced by ketamine (30 mg kg−1) via the PGRMC1 pathway in rat brains, including hippocampus and prefrontal cortex (PFC). Cognitive performance was evaluated by Morris water maze (MWM) test. Western blot and real-time quantitative polymerase chain reaction were utilized to assess the expression changes of protein and mRNA. Additionally, concentrations of PROG and ALLO in plasma, hippocampus and PFC were measured by a liquid chromatography-tandem mass spectrometry method. We demonstrated that PROG or ALLO could reverse the impaired spatial learning and memory abilities induced by ketamine, accompanied with the upregulation of PGRMC1/EGFR/GLP-1R/PI3K/Akt pathway. Additionally, the coadministration of AG205 abolished their neuroprotective effects and induced cognitive deficits similar with ketamine. More importantly, PROG concentrations were markedly elevated in PROG-treated groups in hippocampus, PFC and plasma, so as for ALLO concentrations in ALLO-treated groups. Interestingly, ALLO (16 mg kg−1) significantly increased the levels of PROG. These findings suggest that PROG can exert its neuroprotective effects via activating the PGRMC1/EGFR/GLP-1R/PI3K/Akt pathway in the brain, whereas ALLO also restores cognitive deficits partially via increasing the level of PROG in the brain to activate the PGRMC1 pathway.
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Affiliation(s)
- Ting Cao
- Department of Pharmacy, Second Xiangya Hospital, Central South University, Changsha, China.,Institute of Clinical Pharmacy, Second Xiangya Hospital, Central South University, Changsha, China
| | - MiMi Tang
- Department of Pharmacy, Xiangya Hospital of Central South University, Changsha, China.,Institute of Hospital Pharmacy, Xiangya Hospital, Central South University, Changsha, China
| | - Pei Jiang
- Institute of Clinical Pharmacology, Jining First People's Hospital, Jining Medical University, Jining, China
| | - BiKui Zhang
- Department of Pharmacy, Second Xiangya Hospital, Central South University, Changsha, China.,Institute of Clinical Pharmacy, Second Xiangya Hospital, Central South University, Changsha, China
| | - XiangXin Wu
- Department of Pharmacy, Second Xiangya Hospital, Central South University, Changsha, China.,Institute of Clinical Pharmacy, Second Xiangya Hospital, Central South University, Changsha, China
| | - Qian Chen
- Department of Pharmacy, Second Xiangya Hospital, Central South University, Changsha, China.,Institute of Clinical Pharmacy, Second Xiangya Hospital, Central South University, Changsha, China
| | - CuiRong Zeng
- Department of Pharmacy, Second Xiangya Hospital, Central South University, Changsha, China.,Institute of Clinical Pharmacy, Second Xiangya Hospital, Central South University, Changsha, China
| | - NaNa Li
- Department of Pharmacy, Second Xiangya Hospital, Central South University, Changsha, China.,Institute of Clinical Pharmacy, Second Xiangya Hospital, Central South University, Changsha, China
| | - ShuangYang Zhang
- Department of Pharmacy, Second Xiangya Hospital, Central South University, Changsha, China.,Institute of Clinical Pharmacy, Second Xiangya Hospital, Central South University, Changsha, China
| | - HuaLin Cai
- Department of Pharmacy, Second Xiangya Hospital, Central South University, Changsha, China.,Institute of Clinical Pharmacy, Second Xiangya Hospital, Central South University, Changsha, China
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15
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Accioly NE, Guedes RCA. Topical cortical application of ovarian hormones and modulation of brain electrical activity: analysis of spreading depression in well-nourished and malnourished female rats. Nutr Neurosci 2020; 23:887-895. [DOI: 10.1080/1028415x.2019.1575574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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16
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Tozzi A, Bellingacci L, Pettorossi VE. Rapid Estrogenic and Androgenic Neurosteroids Effects in the Induction of Long-Term Synaptic Changes: Implication for Early Memory Formation. Front Neurosci 2020; 14:572511. [PMID: 33192257 PMCID: PMC7653679 DOI: 10.3389/fnins.2020.572511] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Accepted: 08/21/2020] [Indexed: 11/17/2022] Open
Abstract
Mounting experimental evidence demonstrate that sex neuroactive steroids (neurosteroids) are essential for memory formation. Neurosteroids have a profound impact on the function and structure of neural circuits and their local synthesis is necessary for the induction of both long-term potentiation (LTP) and long-term depression (LTD) of synaptic transmission and for neural spine formation in different areas of the central nervous system (CNS). Several studies demonstrated that in the hippocampus, 17β-estradiol (E2) is necessary for inducing LTP, while 5α-dihydrotestosterone (DHT) is necessary for inducing LTD. This contribution has been proven by administering sex neurosteroids in rodent models and by using blocking agents of their synthesis or of their specific receptors. The general opposite role of sex neurosteroids in synaptic plasticity appears to be dependent on their different local availability in response to low or high frequency of synaptic stimulation, allowing the induction of bidirectional synaptic plasticity. The relevant contribution of these neurosteroids to synaptic plasticity has also been described in other brain regions involved in memory processes such as motor learning, as in the case of the vestibular nuclei, the cerebellum, and the basal ganglia, or as the emotional circuit of the amygdala. The rapid effects of sex neurosteroids on neural synaptic plasticity need the maintenance of a tonic or phasic local steroid synthesis determined by neural activity but might also be influenced by circulating hormones, age, and gender. To disclose the exact mechanisms how sex neurosteroids participate in finely tuning long-term synaptic changes and spine remodeling, further investigation is required.
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Affiliation(s)
- Alessandro Tozzi
- Department of Experimental Medicine, University of Perugia, Perugia, Italy
| | - Laura Bellingacci
- Department of Experimental Medicine, University of Perugia, Perugia, Italy
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17
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Nicholson K, MacLusky NJ, Leranth C. Synaptic effects of estrogen. VITAMINS AND HORMONES 2020; 114:167-210. [PMID: 32723543 DOI: 10.1016/bs.vh.2020.06.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The concept that estradiol may act as a local neuromodulator in the brain, rapidly affecting connectivity and synaptic function, has been firmly established by research over the last 30 years. De novo synthesis of estradiol within the brain as well as signaling mechanisms mediating responses to the hormone have been demonstrated, along with morphological evidence indicating rapid changes in synaptic input following increases in local estradiol levels. These rapid synaptic effects may play important roles in both physiological and pathophysiological responses to changes in circulating hormone levels, as well as in neurodegenerative disease. How local effects of estradiol on synaptic plasticity are integrated into changes in the overall activity of neural networks in the brain, however, remains a subject that is only incompletely understood.
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Affiliation(s)
- Kate Nicholson
- Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada
| | - Neil J MacLusky
- Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada
| | - Csaba Leranth
- Department of Obstetrics, Gynecology and Reproductive Sciences, Yale University, School of Medicine, New Haven, CT, United States.
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18
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Proaño SB, Meitzen J. Estradiol decreases medium spiny neuron excitability in female rat nucleus accumbens core. J Neurophysiol 2020; 123:2465-2475. [PMID: 32432511 DOI: 10.1152/jn.00210.2020] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The menstrual cycle in humans and its analogous cycle in rodents, the estrous cycle, modulate brain function and behavior. Both cycles are characterized by the cyclical fluctuation of ovarian hormones including estrogens such as estradiol. Estradiol induces cycle- and sex-dependent differences in the phenotype and incidence of many behaviors, including those related to reward and motivation. The nucleus accumbens core (AcbC), a limbic and premotor system nexus region, directly regulates these behaviors. We previously showed that the estrous cycle modulates intrinsic excitability and excitatory synapse properties of medium spiny neurons (MSNs) in the AcbC. The identity of the underlying hormone mechanism is unknown, with estradiol being a prime candidate. The present study tests the hypothesis that estradiol induces estrous cycle-relevant differences in MSN electrophysiology. To accomplish this goal, a time- and dose-dependent estradiol replacement paradigm designed to simulate the rise of circulating estradiol levels across the estrous cycle was employed in ovariectomized adult female rats as well as a vehicle control group. Estradiol replacement decreased MSN excitability by modulating properties such as resting membrane potential, input resistance in both the linear and rectified ranges, and rheobase compared with vehicle-treated females. These differences in MSN excitability mimic those previously described regarding estrous cycle effects on MSN electrophysiology. Excitatory synapse properties were not modulated in response to this estradiol replacement paradigm. These data are the first to demonstrate that an estrous cycle-relevant estradiol exposure modulates MSN electrophysiology, providing evidence of the fundamental neuroendocrine mechanisms regulating the AcbC.NEW & NOTEWORTHY The present study shows, for the first time, that an estrous cycle-relevant estradiol exposure modulates nucleus accumbens neuron excitability. This evidence provides insight into the neuroendocrine mechanisms by which estradiol cyclically alters neuron properties during the estrous cycle. Overall, these data emphasize the significant influence of hormone action in the brain and especially individual neuron physiology.
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Affiliation(s)
- Stephanie B Proaño
- Graduate Program in Biology, North Carolina State University, Raleigh, North Carolina.,W. M. Keck Center for Behavioral Biology, North Carolina State University, Raleigh, North Carolina.,Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina
| | - John Meitzen
- W. M. Keck Center for Behavioral Biology, North Carolina State University, Raleigh, North Carolina.,Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina.,Center for Human Health and the Environment, North Carolina State University, Raleigh, North Carolina
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19
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Clements L, Harvey J. Activation of oestrogen receptor α induces a novel form of LTP at hippocampal temporoammonic-CA1 synapses. Br J Pharmacol 2020; 177:642-655. [PMID: 31637699 DOI: 10.1111/bph.14880] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 08/30/2019] [Accepted: 09/07/2019] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND AND PURPOSE 17β estradiol (E2) rapidly regulates excitatory synaptic transmission at the classical Schaffer collateral (SC) input to hippocampal CA1 neurons. However, the impact of E2 on excitatory synaptic transmission at the distinct temporoammonic (TA) input to CA1 neurons and the oestrogen receptors involved is less clear. EXPERIMENTAL APPROACH Extracellular recordings were used to monitor excitatory synaptic transmission in hippocampal slices from juvenile male (P11-24) Sprague Dawley rats. Immunocytochemistry combined with confocal microscopy was used to monitor the surface expression of the AMPA receptor (AMPAR) subunit, GluA1 in hippocampal neurons cultured from neonatal (P0-3) rats. KEY RESULTS Here, we show that E2 induces a novel form of LTP at TA-CA1 synapses, an effect mirrored by the ERα agonist, PPT, and blocked by an ERα antagonist. ERα-induced LTP is NMDA receptor (NMDAR)-dependent and involves a postsynaptic expression mechanism that requires PI 3-kinase signalling and synaptic insertion of GluA2-lacking AMPARs. ERα-induced LTP has overlapping expression mechanisms with classical Hebbian LTP, as HFS-induced LTP occluded PPT-induced LTP and vice versa. In addition, activity-dependent LTP was blocked by the ERα antagonist, suggesting that ERα activation is involved in NMDA-LTP at TA-CA1 synapses. CONCLUSION AND IMPLICATIONS ERα induces a novel form of LTP at juvenile male hippocampal TA-CA1 synapses. As TA-CA1 synapses are implicated in episodic memory processes and are an early target for neurodegeneration, these findings have important implications for the role of oestrogens in CNS health and neurodegenerative disease.
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Affiliation(s)
- Leigh Clements
- Division of Systems Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, UK
| | - Jenni Harvey
- Division of Systems Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, UK
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20
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Çalışkan G, Raza SA, Demiray YE, Kul E, Sandhu KV, Stork O. Depletion of dietary phytoestrogens reduces hippocampal plasticity and contextual fear memory stability in adult male mouse. Nutr Neurosci 2019; 24:951-962. [PMID: 31814540 DOI: 10.1080/1028415x.2019.1698826] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Introduction: Phytoestrogens are non-steroidal estrogen analogues and are found primarily in soy products. They have received increasing attention as dietary supplements for estrogen deficiency and as modulators of endogenous estrogen functions, including cognition and emotion. In addition to modifying the levels of circulating sex hormones, phytoestrogens also exert direct effects on estrogen and androgen receptors in the brain and thus effectively modulate the neural circuit functions.Objective: The aim of this study was to investigate the long-term effects of low phytoestrogen intake (∼6 weeks) on the hippocampal plasticity and hippocampus-dependent memory formation in the adult C57BL/6 male mice.Methods and Results: In comparison to mice on a diet with normal phytoestrogen content, mice on low phytoestrogen diet showed a significant reduction in the phosphorylation of NR2B subunit, a molecular correlate of plasticity in the Schaffer collateral-CA1 synapse. We observed a profound decrease in long-term potentiation (LTP) in the ventral hippocampus, whereas no effect on plasticity was evident in its dorsal portion. Furthermore, we demonstrated that acute perfusion of slices with an estrogen analogue equol, an isoflovane metabolized from daidzein produced by the bacterial flora in the gut, was able to rescue the observed LTP deficit. Examining potential behavioral correlates of the plasticity attenuation, we found that mice on phytoestrogen-free diet display decreased contextual fear memory at remote but not at recent time points after training.Conclusions: Our data suggests that nutritional phytoestrogens have profound effects on the plasticity in the ventral hippocampus and ventral hippocampus-dependent memory.
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Affiliation(s)
- Gürsel Çalışkan
- Institute of Biology, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany.,Center for Behavioral Brain Sciences (CBBS), Magdeburg, Germany
| | - Syed Ahsan Raza
- Institute of Biology, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany.,Center for Behavioral Brain Sciences (CBBS), Magdeburg, Germany
| | - Yunus E Demiray
- Institute of Biology, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany
| | - Emre Kul
- Institute of Biology, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany
| | - Kiran V Sandhu
- Institute of Biology, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany.,APC Microbiome Ireland, University College Cork, Cork, Ireland
| | - Oliver Stork
- Institute of Biology, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany.,Center for Behavioral Brain Sciences (CBBS), Magdeburg, Germany
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21
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Tozzi A, Durante V, Manca P, Di Mauro M, Blasi J, Grassi S, Calabresi P, Kawato S, Pettorossi VE. Bidirectional Synaptic Plasticity Is Driven by Sex Neurosteroids Targeting Estrogen and Androgen Receptors in Hippocampal CA1 Pyramidal Neurons. Front Cell Neurosci 2019; 13:534. [PMID: 31866827 PMCID: PMC6904272 DOI: 10.3389/fncel.2019.00534] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 11/18/2019] [Indexed: 11/23/2022] Open
Abstract
Neuroactive estrogenic and androgenic steroids influence synaptic transmission, finely modulating synaptic plasticity in several brain regions including the hippocampus. While estrogens facilitate long-term potentiation (LTP), androgens are involved in the induction of long-term depression (LTD) and depotentiation (DP) of synaptic transmission. To examine sex neurosteroid-dependent LTP and LTD in single cells, patch-clamp recordings from hippocampal CA1 pyramidal neurons of male rats and selective antagonists for estrogen receptors (ERs) and androgen (AR) receptors were used. LTP induced by high-frequency stimulation (HFS) depended on activation of ERs since it was prevented by the ER antagonist ICI 182,780 in most of the neurons. Application of the selective antagonists for ERα (MPP) or ERβ (PHTPP) caused a reduction of the LTP amplitude, while these antagonists in combination, prevented LTP completely. LTP was never affected by blocking AR with the specific antagonist flutamide. Conversely, LTD and DP, elicited by low-frequency stimulation (LFS), were impeded by flutamide, but not by ICI 182,780, in most neurons. In few cells, LTD was even reverted to LTP by flutamide. Moreover, the combined application of both ER and AR antagonists completely prevented both LTP and LTD/DP in the same neuron. The current study demonstrates that the activation of ERs is necessary for inducing LTP in hippocampal pyramidal neurons, whereas the activation of ARs is required for LTD and DP. Moreover, both estrogen- and androgen-dependent LTP and LTD can be expressed in the same pyramidal neurons, suggesting that the activation of sex neurosteroids signaling pathways is responsible for bidirectional synaptic plasticity.
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Affiliation(s)
- Alessandro Tozzi
- Department of Experimental Medicine, Section of Physiology and Biochemistry, University of Perugia, Perugia, Italy
| | - Valentina Durante
- Department of Medicine, Section of Neurological Clinic, "Santa Maria della Misericordia" Hospital, University of Perugia, Perugia, Italy
| | - Paolo Manca
- Department de Patologia i Terapèutica Experimental, Facultat de Medicina, Campus de Bellvitge, Universitat de Barcelona, Barcelona, Spain
| | - Michela Di Mauro
- Department of Experimental Medicine, Section of Physiology and Biochemistry, University of Perugia, Perugia, Italy
| | - Juan Blasi
- Department de Patologia i Terapèutica Experimental, Facultat de Medicina, Campus de Bellvitge, Universitat de Barcelona, Barcelona, Spain
| | - Silvarosa Grassi
- Department of Experimental Medicine, Section of Physiology and Biochemistry, University of Perugia, Perugia, Italy
| | - Paolo Calabresi
- Department of Medicine, Section of Neurological Clinic, "Santa Maria della Misericordia" Hospital, University of Perugia, Perugia, Italy
| | - Suguru Kawato
- Department of Cognitive Neuroscience, Faculty of Pharma-Science, Teikyo University, Tokyo, Japan.,Department of Biophysics and Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan
| | - Vito Enrico Pettorossi
- Department of Experimental Medicine, Section of Physiology and Biochemistry, University of Perugia, Perugia, Italy
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22
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Tu LL, Sun Q, Wei LL, Shi J, Li JP. Upregulation of GABA receptor promotes long-term potentiation and depotentiation in the hippocampal CA1 region of mice with type 2 diabetes mellitus. Exp Ther Med 2019; 18:2429-2436. [PMID: 31555354 PMCID: PMC6755275 DOI: 10.3892/etm.2019.7868] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Accepted: 04/18/2019] [Indexed: 12/13/2022] Open
Abstract
Type 2 diabetes mellitus (T2DM) is a long-term metabolic disorder characterized by high blood sugar levels, insulin resistance and a relative lack of insulin. A previous study has reported that an association exists between γ-aminobutyric acid (GABA) and the hippocampus. The current study therefore aimed to assess the effect of the GABA receptor (GABA-R) on the long-term potentiation (LTP) and depotentiation of the hippocampal CA1 region in mice with T2DM. Mice were divided into four groups: A normal group consisting of healthy mice and a GABA-R, negative control and blank group all comprising T2DM mice. The weight and blood glucose level of all mice were measured and GABA-R mRNA and protein expression were detected. A hydroxyl free radical (OH-) kit was used to determine the hippocampal OH-content. Using an electrophysiological experiment, the population spike (PS) slope was observed every 5 min. The results revealed that as GABA-R levels increased, the weight, blood glucose level and OH− content of the T2DM mice significantly decreased, and the neuron microstructures in the mice hippocampal tissue improved. The PS slope also significantly increased and the level of depotentiation improved. The results of the current study support the theory that the upregulation of GABA-R protects the neuronal ultrastructure and promotes LTP and depotentiation in the hippocampal CA1 region by inhibiting the accumulation of OH− in T2DM mice.
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Affiliation(s)
- Li-Li Tu
- Department of Geratology, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, Sichuan 610072, P.R. China
| | - Qin Sun
- Center of Diabetes Mellitus, School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan 610000, P.R. China
| | - Ling-Ling Wei
- Center of Diabetes Mellitus, School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan 610000, P.R. China
| | - Jing Shi
- Center of Diabetes Mellitus, School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan 610000, P.R. China
| | - Jian-Ping Li
- Department of Geratology, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, Sichuan 610072, P.R. China
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23
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Sex Differences in Neuropathology and Cognitive Behavior in APP/PS1/tau Triple-Transgenic Mouse Model of Alzheimer's Disease. Neurosci Bull 2018; 34:736-746. [PMID: 30099679 DOI: 10.1007/s12264-018-0268-9] [Citation(s) in RCA: 97] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Accepted: 06/16/2018] [Indexed: 10/28/2022] Open
Abstract
Alzheimer's disease (AD) is the most common form of dementia among the elderly, characterized by amyloid plaques, neurofibrillary tangles, and neuroinflammation in the brain, as well as impaired cognitive behaviors. A sex difference in the prevalence of AD has been noted, while sex differences in the cerebral pathology and relevant molecular mechanisms are not well clarified. In the present study, we systematically investigated the sex differences in pathological characteristics and cognitive behavior in 12-month-old male and female APP/PS1/tau triple-transgenic AD mice (3×Tg-AD mice) and examined the molecular mechanisms. We found that female 3×Tg-AD mice displayed more prominent amyloid plaques, neurofibrillary tangles, neuroinflammation, and spatial cognitive deficits than male 3×Tg-AD mice. Furthermore, the expression levels of hippocampal protein kinase A-cAMP response element-binding protein (PKA-CREB) and p38-mitogen-activated protein kinases (MAPK) also showed sex difference in the AD mice, with a significant increase in the levels of p-PKA/p-CREB and a decrease in the p-p38 in female, but not male, 3×Tg-AD mice. We suggest that an estrogen deficiency-induced PKA-CREB-MAPK signaling disorder in 12-month-old female 3×Tg-AD mice might be involved in the serious pathological and cognitive damage in these mice. Therefore, sex differences should be taken into account in investigating AD biomarkers and related target molecules, and estrogen supplementation or PKA-CREB-MAPK stabilization could be beneficial in relieving the pathological damage in AD and improving the cognitive behavior of reproductively-senescent females.
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Brocca ME, Garcia-Segura LM. Non-reproductive Functions of Aromatase in the Central Nervous System Under Physiological and Pathological Conditions. Cell Mol Neurobiol 2018; 39:473-481. [PMID: 30084008 DOI: 10.1007/s10571-018-0607-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 07/25/2018] [Indexed: 02/07/2023]
Abstract
The modulation of brain function and behavior by steroid hormones was classically associated with their secretion by peripheral endocrine glands. The discovery that the brain expresses the enzyme aromatase, which produces estradiol from testosterone, expanded this traditional concept. One of the best-studied roles of brain estradiol synthesis is the control of reproductive behavior. In addition, there is increasing evidence that estradiol from neural origin is also involved in a variety of non-reproductive functions. These include the regulation of neurogenesis, neuronal development, synaptic transmission, and plasticity in brain regions not directly related with the control of reproduction. Central aromatase is also involved in the modulation of cognition, mood, and non-reproductive behaviors. Furthermore, under pathological conditions aromatase is upregulated in the central nervous system. This upregulation represents a neuroprotective and likely also a reparative response by increasing local estradiol levels in order to maintain the homeostasis of the neural tissue. In this paper, we review the non-reproductive functions of neural aromatase and neural-derived estradiol under physiological and pathological conditions. We also consider the existence of sex differences in the role of the enzyme in both contexts.
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Affiliation(s)
- Maria Elvira Brocca
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain.
| | - Luis Miguel Garcia-Segura
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
- Centro de Investigación Biomédica en Red Fragilidad y Envejecimiento Saludable (CIBERFES), Instituto de Salud Carlos III, Madrid, Spain
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Soma M, Kim J, Kato A, Kawato S. Src Kinase Dependent Rapid Non-genomic Modulation of Hippocampal Spinogenesis Induced by Androgen and Estrogen. Front Neurosci 2018; 12:282. [PMID: 29765299 PMCID: PMC5938344 DOI: 10.3389/fnins.2018.00282] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Accepted: 04/10/2018] [Indexed: 11/13/2022] Open
Abstract
Dendritic spine is a small membranous protrusion from a neuron's dendrite that typically receives input from an axon terminal at the synapse. Memories are stored in synapses which consist of spines and presynapses. Rapid modulations of dendritic spines induced by hippocampal sex steroids, including dihydrotestosterone (DHT), testosterone (T), and estradiol (E2), are essential for synaptic plasticity. Molecular mechanisms underlying the rapid non-genomic modulation through synaptic receptors of androgen (AR) and estrogen (ER) as well as its downstream kinase signaling, however, have not been well understood. We investigated the possible involvement of Src tyrosine kinase in rapid changes of dendritic spines in response to androgen and estrogen, including DHT, T, and E2, using hippocampal slices from adult male rats. We found that the treatments with DHT (10 nM), T (10 nM), and E2 (1 nM) increased the total density of spines by ~1.22 to 1.26-fold within 2 h using super resolution confocal imaging of Lucifer Yellow-injected CA1 pyramidal neurons. We examined also morphological changes of spines in order to clarify differences between three sex steroids. From spine head diameter analysis, DHT increased middle- and large-head spines, whereas T increased small- and middle-head spines, and E2 increased small-head spines. Upon application of Src tyrosine kinase inhibitor, the spine increases induced through DHT, T, and E2 treatments were completely blocked. These results imply that Src kinase is essentially involved in sex steroid-induced non-genomic modulation of the spine density and morphology. These results also suggest that rapid effects of exogenously applied androgen and estrogen can occur in steroid-depleted conditions, including “acute” hippocampal slices and the hippocampus of gonadectomized animals.
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Affiliation(s)
- Mika Soma
- Department of Cognitive Neuroscience, Faculty of Pharma-Science, Teikyo University, Itabashi, Japan
| | - Jonghyuk Kim
- Department of Cognitive Neuroscience, Faculty of Pharma-Science, Teikyo University, Itabashi, Japan
| | - Asami Kato
- Department of Cognitive Neuroscience, Faculty of Pharma-Science, Teikyo University, Itabashi, Japan
| | - Suguru Kawato
- Department of Cognitive Neuroscience, Faculty of Pharma-Science, Teikyo University, Itabashi, Japan.,Department of Urology, Graduate School of Medicine, Juntendo University, Hongo, Japan.,Department of Biophysics and Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Meguro, Japan
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Munk AJL, Zoeller AC, Hennig J. Fluctuations of estradiol during women's menstrual cycle: Influences on reactivity towards erotic stimuli in the late positive potential. Psychoneuroendocrinology 2018. [PMID: 29518692 DOI: 10.1016/j.psyneuen.2018.02.028] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
BACKGROUND While several studies examined the reactivity towards negative emotional stimuli across women's menstrual cycle, only few investigated responses to positive emotional cues in association with sexual hormones on a neural level. Therefore, the aim of the current EEG-experiment was to study the differential reactivity towards positive (erotic) words during the menstrual cycle (i.e. with fluctuations in the steroids estradiol and progesterone) in the late positive potential (LPP). Regarding reactivity towards erotic stimuli, the LPP is seen as the most relevant ERP-component, as more positive amplitudes in the LPP reflect larger incentive salience and higher arousal. The LPP towards erotic words was expected to be more pronounced during fertile phases of the menstrual cycle (around ovulation). Furthermore, associations with hormonal concentrations of estradiol and progesterone were investigated. METHOD 19 young, free cycling women were tested in an Erotic Stroop paradigm during the follicular phase, ovulation, and the luteal phase in a balanced cross-over design, while electroencephalogram (EEG) was recorded. RESULTS LPPs in reaction to erotic compared to neutral words were larger in every phase. During the follicular phase and ovulation, higher estradiol-concentrations were associated with more positive LPP-amplitudes towards erotic- than to neutral words. No effects of progesterone, as well as no effects of cycle phase, were evident. Results are being discussed regarding implications for further research.
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Affiliation(s)
- Aisha J L Munk
- Department of Differential and Biological Psychology, University of Giessen, Germany.
| | - Aaron C Zoeller
- Department of General Psychology, University of Giessen, Germany
| | - Juergen Hennig
- Department of Differential and Biological Psychology, University of Giessen, Germany
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Neural-derived estradiol regulates brain plasticity. J Chem Neuroanat 2018; 89:53-59. [DOI: 10.1016/j.jchemneu.2017.04.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Revised: 03/16/2017] [Accepted: 04/12/2017] [Indexed: 01/12/2023]
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Murakami G, Hojo Y, Kato A, Komatsuzaki Y, Horie S, Soma M, Kim J, Kawato S. Rapid nongenomic modulation by neurosteroids of dendritic spines in the hippocampus: Androgen, oestrogen and corticosteroid. J Neuroendocrinol 2018; 30. [PMID: 29194818 DOI: 10.1111/jne.12561] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2017] [Revised: 11/24/2017] [Accepted: 11/27/2017] [Indexed: 12/22/2022]
Abstract
Memories are stored in synapses that consist of axon terminals and dendritic spines. Dendritic spines are postsynaptic structures of synapses and are essential for synaptic plasticity and cognition. Therefore, extensive investigations concerning the functions and structures of spines have been performed. Sex steroids and stress steroids have been shown to modulate hippocampal synapses. Although the rapid modulatory action of sex steroids on synapses has been studied in hippocampal neurones over several decades, the essential molecular mechanisms have not been fully understood. Here, a description of kinase-dependent signalling mechanisms is provided that can explain the rapid nongenomic modulation of dendritic spinogenesis in rat and mouse hippocampal slices by the application of sex steroids, including dihydrotestosterone, testosterone, oestradiol and progesterone. We also indicate the role of synaptic (classic) sex steroid receptors that trigger these rapid synaptic modulations. Moreover, we describe rapid nongenomic spine modulation by applying corticosterone, which is an acute stress model of the hippocampus. The explanations for the results obtained are mainly based on the optical imaging of dendritic spines. Comparisons are also performed with results obtained from other types of imaging, including electron microscopic imaging. Relationships between spine modulation and modulation of cognition are discussed. We recognise that most of rapid effects of exogenously applied oestrogen and androgen were observed in steroid-depleted conditions, including acute slices of the hippocampus, castrated male animals and ovariectomised female animals. Therefore, the previously observed effects can be considered as a type of recovery event, which may be essentially similar to hormone replacement therapy under hormone-decreased conditions. On the other hand, in gonadally intact young animals with high levels of endogenous sex hormones, further supplementation of sex hormones might not be effective, whereas the infusion of blockers for steroid receptors or kinases may be effective, with respect to suppressing sex hormone functions, thus providing useful information regarding molecular mechanisms.
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Affiliation(s)
- G Murakami
- Department of Liberal Arts, Faculty of Medicine, Saitama Medical University, Iruma, Saitama, Japan
| | - Y Hojo
- Department of Biochemistry, Faculty of Medicine, Saitama Medical University, Iruma, Saitama, Japan
| | - A Kato
- Department of Biophysics and Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, Meguro, Tokyo, Japan
| | - Y Komatsuzaki
- Department of Physics, College of Science and Technology, Nihon University, Chiyoda, Tokyo, Japan
| | - S Horie
- Department of Urology, Graduate School of Medicine, Juntendo University, Hongo, Tokyo, Japan
| | - M Soma
- Department of Cognitive Neuroscience, Faculty of Pharma-Science, Teikyo University, Itabashi, Tokyo, Japan
| | - J Kim
- Department of Cognitive Neuroscience, Faculty of Pharma-Science, Teikyo University, Itabashi, Tokyo, Japan
| | - S Kawato
- Department of Biophysics and Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, Meguro, Tokyo, Japan
- Department of Urology, Graduate School of Medicine, Juntendo University, Hongo, Tokyo, Japan
- Department of Cognitive Neuroscience, Faculty of Pharma-Science, Teikyo University, Itabashi, Tokyo, Japan
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Hojo Y, Kawato S. Neurosteroids in Adult Hippocampus of Male and Female Rodents: Biosynthesis and Actions of Sex Steroids. Front Endocrinol (Lausanne) 2018; 9:183. [PMID: 29740398 PMCID: PMC5925962 DOI: 10.3389/fendo.2018.00183] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Accepted: 04/04/2018] [Indexed: 12/13/2022] Open
Abstract
The brain is not only the target of steroid hormones but also is able to locally synthesize steroids de novo. Evidence of the local production of steroids in the brain has been accumulating in various vertebrates, including teleost fish, amphibia, birds, rodents, non-human primates, and humans. In this review, we mainly focus on the local production of sex steroids in the hippocampal neurons of adult rodents (rats and mice), a center for learning and memory. From the data of the hippocampus of adult male rats, hippocampal principal neurons [pyramidal cells in CA1-CA3 and granule cells in dentate gyrus (DG)] have a complete system for biosynthesis of sex steroids. Liquid chromatography with tandem-mass-spectrometry (LC-MS/MS) enabled us to accurately determine the levels of hippocampal sex steroids including 17β-estradiol (17β-E2), testosterone (T), and dihydrotestosterone (DHT), which are much higher than those in blood. Next, we review the steroid synthesis in the hippocampus of female rats, since previous knowledge had been biased toward the data from males. Recently, we clarified that the levels of hippocampal steroids fluctuate in adult female rats across the estrous cycle. Accurate determination of hippocampal steroids at each stage of the estrous cycle is of importance for providing the account for the fluctuation of female hippocampal functions, including spine density, long-term potentiation (LTP) and long-term depression (LTD), and learning and memory. These functional fluctuations in female had been attributed to the level of circulation-derived steroids. LC-MS/MS analysis revealed that the dendritic spine density in CA1 of adult female hippocampus correlates with the levels of hippocampal progesterone and 17β-E2. Finally, we introduce the direct evidence of the role of hippocampus-synthesized steroids in hippocampal function including neurogenesis, LTP, and memory consolidation. Mild exercise (2 week of treadmill running) elevated synthesis of DHT in the hippocampus, but not in the testis, of male rats, resulting in enhancement of neurogenesis in DG. Concerning synaptic plasticity, hippocampus-synthesized E2 is required for LTP induction, whereas hippocampus-synthesized DHT is required for LTD induction. Furthermore, hippocampus-synthesized E2 is involved in memory consolidation tested by object recognition and object placement tasks, both of which are hippocampus-dependent.
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Affiliation(s)
- Yasushi Hojo
- Department of Biochemistry, Faculty of Medicine, Saitama Medical University, Moroyama, Saitama, Japan
- *Correspondence: Yasushi Hojo,
| | - Suguru Kawato
- Department of Biophysics and Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan
- Department of Urology, Graduate School of Medicine, Juntendo University, Tokyo, Japan
- Department of Cognitive Neuroscience, Faculty of Pharma-Science, Teikyo University, Tokyo, Japan
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Zhao Y, Yu Y, Zhang Y, He L, Qiu L, Zhao J, Liu M, Zhang J. Letrozole regulates actin cytoskeleton polymerization dynamics in a SRC-1 dependent manner in the hippocampus of mice. J Steroid Biochem Mol Biol 2017; 167:86-97. [PMID: 27866972 DOI: 10.1016/j.jsbmb.2016.11.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Revised: 10/24/2016] [Accepted: 11/16/2016] [Indexed: 12/21/2022]
Abstract
In the hippocampus, local estrogens (E2) derived from testosterone that is catalyzed by aromatase play important roles in the regulation of hippocampal neural plasticity, but the underlying mechanisms remain unclear. The actin cytoskeleton contributes greatly to hippocampal synaptic plasticity; however, whether it is regulated by local E2 and the related mechanisms remain to be elucidated. In this study, we first examined the postnatal developmental profiles of hippocampal aromatase and specific proteins responsible for actin cytoskeleton dynamics. Then we used aromatase inhibitor letrozole (LET) to block local E2 synthesis and examined the changes of these proteins and steroid receptor coactivator-1 (SRC-1), the predominant coactivator for steroid nuclear receptors. Finally, SRC-1 specific RNA interference was used to examine the effects of SRC-1 on the expression of these actin remodeling proteins. The results showed a V-type profile for aromatase and increased profiles for actin cytoskeleton proteins in both male and female hippocampus without obvious sex differences. LET treatment dramatically decreased the F-actin/G-actin ratio, the expression of Rictor, phospho-AKT (ser473), Profilin-1, phospho-Cofilin (Ser3), and SRC-1 in a dose-dependent manner. In vitro studies demonstrated that LET induced downregulation of these proteins could be reversed by E2, and E2 induced increase of these proteins were significantly suppressed by SRC-1 shRNA interference. These results for the first time clearly demonstrated that local E2 inhibition could induce aberrant actin polymerization; they also showed an important role of SRC-1 in the mediation of local E2 action on hippocampal synaptic plasticity by regulation of actin cytoskeleton dynamics.
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Affiliation(s)
- Yangang Zhao
- Department of Neurobiology, Chongqing Key Laboratory of Neurobiology, Third Military Medical University, Chongqing 400038, China
| | - Yanlan Yu
- Student Brigade, Third Military Medical University, Chongqing 400038, China
| | - Yuanyuan Zhang
- Department of Neurobiology, Chongqing Key Laboratory of Neurobiology, Third Military Medical University, Chongqing 400038, China
| | - Li He
- School of Nursing, Third Military Medical University, Chongqing 400038, China
| | - Linli Qiu
- School of Nursing, Third Military Medical University, Chongqing 400038, China; Department of Nursing, Sichuan Nursing Vocational College, Chengdu 610100, China
| | - Jikai Zhao
- Department of Neurobiology, Chongqing Key Laboratory of Neurobiology, Third Military Medical University, Chongqing 400038, China
| | - Mengying Liu
- Department of Neurobiology, Chongqing Key Laboratory of Neurobiology, Third Military Medical University, Chongqing 400038, China
| | - Jiqiang Zhang
- Department of Neurobiology, Chongqing Key Laboratory of Neurobiology, Third Military Medical University, Chongqing 400038, China.
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Di Mauro M, Tozzi A, Calabresi P, Pettorossi VE, Grassi S. Different synaptic stimulation patterns influence the local androgenic and estrogenic neurosteroid availability triggering hippocampal synaptic plasticity in the male rat. Eur J Neurosci 2017; 45:499-509. [DOI: 10.1111/ejn.13455] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Revised: 10/21/2016] [Accepted: 10/27/2016] [Indexed: 01/01/2023]
Affiliation(s)
- Michela Di Mauro
- Dipartimento di Medicina Sperimentale Sezione di Fisiologia e Biochimica Università di Perugia Via Gambuli 06156 Perugia Italy
| | - Alessandro Tozzi
- Dipartimento di Medicina Sperimentale Sezione di Fisiologia e Biochimica Università di Perugia Via Gambuli 06156 Perugia Italy
- Fondazione Santa Lucia – I.R.C.C.S. Rome Italy
| | - Paolo Calabresi
- Fondazione Santa Lucia – I.R.C.C.S. Rome Italy
- Dipartimento di Medicina Clinica Neurologica Università di Perugia Perugia Italy
| | - Vito Enrico Pettorossi
- Dipartimento di Medicina Sperimentale Sezione di Fisiologia e Biochimica Università di Perugia Via Gambuli 06156 Perugia Italy
| | - Silvarosa Grassi
- Dipartimento di Medicina Sperimentale Sezione di Fisiologia e Biochimica Università di Perugia Via Gambuli 06156 Perugia Italy
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Qiu L, Zhao Y, Guo Q, Zhang Y, He L, Li W, Zhang J. Dose-dependent regulation of steroid receptor coactivator-1 and steroid receptors by testosterone propionate in the hippocampus of adult male mice. J Steroid Biochem Mol Biol 2016; 156:23-31. [PMID: 26607693 DOI: 10.1016/j.jsbmb.2015.11.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Revised: 11/13/2015] [Accepted: 11/16/2015] [Indexed: 01/08/2023]
Abstract
Androgens have been proposed to play important roles in the regulation of hippocampus function either directly, through the androgen receptor (AR), or indirectly, through estrogen receptors (ERs), after aromatization into estradiol. Steroid receptor coactivator-1 (SRC-1) is present in the hippocampus of several species, and its expression is regulated by development and aging, as well as by orchidectomy and aromatase inhibitor letrozole administration, while ovariectomy only transiently downregulated hippocampal SRC-1. However, whether the expression of hippocampal SRC-1 can be directly regulated by testosterone, the principal male sex hormone, remains unclear. In the present study, we investigated the expression of hippocampal SRC-1 after orchidectomy and testosterone treatment using immunohistochemistry and Western blot analysis. We found that while hippocampal SRC-1 was significantly downregulated by orchidectomy (ORX), its expression was rescued by treatment with testosterone in a dose-dependent manner. Furthermore, we noticed that the decreased expression of hippocampal AR, ERs and the synaptic proteins GluR-1 and PSD-95 induced by ORX was also rescued by testosterone treatment in a dose-dependent manner. However, we found that hippocampal membrane estrogen receptor GPR30 and dendritic spine marker spinophilin were not altered by ORX or testosterone treatment. Together, the above results provided the first direct evidence for the androgenic regulation on hippocampal SRC-1, indicating that SRC-1 may be a direct target of androgenic regulation on the hippocampus. Furthermore, because AR and ERs can be differentially regulated by testosterone, and the transcriptional activity requires the involvement of local SRC-1, and considering the complicated regulatory pathway of each individual receptor, the converged hub regulator SRC-1 of these nuclear receptor networks is worthy of further investigation.
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Affiliation(s)
- Linli Qiu
- Department of Neurobiology, Chongqing Key Laboratory of Neurobiology, Third Military Medical University, Chongqing 400038, China; Department of Filed Nursing, School of Nursing, Third Military Medical University, Chongqing 400038, China
| | - Yangang Zhao
- Department of Neurobiology, Chongqing Key Laboratory of Neurobiology, Third Military Medical University, Chongqing 400038, China
| | - Qiang Guo
- Department of Neurobiology, Chongqing Key Laboratory of Neurobiology, Third Military Medical University, Chongqing 400038, China
| | - Yuanyuan Zhang
- Department of Neurobiology, Chongqing Key Laboratory of Neurobiology, Third Military Medical University, Chongqing 400038, China
| | - Li He
- Department of Neurobiology, Chongqing Key Laboratory of Neurobiology, Third Military Medical University, Chongqing 400038, China; Department of Filed Nursing, School of Nursing, Third Military Medical University, Chongqing 400038, China
| | - Wei Li
- Department of Filed Nursing, School of Nursing, Third Military Medical University, Chongqing 400038, China.
| | - Jiqiang Zhang
- Department of Neurobiology, Chongqing Key Laboratory of Neurobiology, Third Military Medical University, Chongqing 400038, China.
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Di Mauro M, Tozzi A, Calabresi P, Pettorossi VE, Grassi S. Neo-synthesis of estrogenic or androgenic neurosteroids determine whether long-term potentiation or depression is induced in hippocampus of male rat. Front Cell Neurosci 2015; 9:376. [PMID: 26483631 PMCID: PMC4591489 DOI: 10.3389/fncel.2015.00376] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 09/08/2015] [Indexed: 11/17/2022] Open
Abstract
Estrogenic and androgenic steroids synthesized in the brain may rapidly modulate synaptic plasticity interacting with specific membrane receptors. We explored by electrophysiological recordings in hippocampal slices of male rat the influence of 17β-estradiol (E2) and 5α-dihydrotestosterone (DHT) neo-synthesis on the synaptic changes induced in the CA1 region. Induction of long-term depression (LTD) and depotentiation (DP) by low frequency stimulation (LFS, 15 min-1 Hz) and of long-term potentiation (LTP) by high frequency stimulation (HFS, 1 s-100 Hz), medium (MFS, 1 s-50 Hz), or weak (WFS, 1 s-25 Hz) frequency stimulation was assayed under inhibitors of enzymes converting testosterone (T) into DHT (5α-reductase) and T into E2 (P450-aromatase). We found that LFS-LTD depends on DHT synthesis, since it was fully prevented under finasteride, an inhibitor of DHT synthesis, and rescued by exogenous DHT, while the E2 synthesis was not involved. Conversely, the full development of HFS-LTP requires the synthesis of E2, as demonstrated by the LTP reduction observed under letrozole, an inhibitor of E2 synthesis, and its full rescue by exogenous E2. For intermediate stimulation protocols DHT, but not E2 synthesis, was involved in the production of a small LTP induced by WFS, while the E2 synthesis was required for the MFS-dependent LTP. Under the combined block of DHT and E2 synthesis all stimulation frequencies induced partial LTP. Overall, these results indicate that DHT is required for converting the partial LTP into LTD whereas E2 is needed for the full expression of LTP, evidencing a key role of the neo-synthesis of sex neurosteroids in determining the direction of synaptic long-term effects.
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Affiliation(s)
- Michela Di Mauro
- Dipartimento di Medicina Sperimentale, Sezione di Fisiologia e Biochimica, Università di Perugia Perugia, Italy
| | - Alessandro Tozzi
- Dipartimento di Medicina Sperimentale, Sezione di Fisiologia e Biochimica, Università di Perugia Perugia, Italy ; Fondazione Santa Lucia - I.R.C.C.S. Roma, Italy
| | - Paolo Calabresi
- Fondazione Santa Lucia - I.R.C.C.S. Roma, Italy ; Dipartimento di Medicina, Clinica Neurologica, Università di Perugia Perugia, Italy
| | - Vito Enrico Pettorossi
- Dipartimento di Medicina Sperimentale, Sezione di Fisiologia e Biochimica, Università di Perugia Perugia, Italy
| | - Silvarosa Grassi
- Dipartimento di Medicina Sperimentale, Sezione di Fisiologia e Biochimica, Università di Perugia Perugia, Italy
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Briz V, Liu Y, Zhu G, Bi X, Baudry M. A novel form of synaptic plasticity in field CA3 of hippocampus requires GPER1 activation and BDNF release. J Cell Biol 2015; 210:1225-37. [PMID: 26391661 PMCID: PMC4586750 DOI: 10.1083/jcb.201504092] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Accepted: 08/19/2015] [Indexed: 01/11/2023] Open
Abstract
Estrogen gates metabotropic glutamate receptor–dependent long-term depression at mossy fiber–CA3 synapses through a mechanism involving GPER1-mediated BDNF release, mTOR-dependent protein synthesis, and proteasome activity. Estrogen is an important modulator of hippocampal synaptic plasticity and memory consolidation through its rapid action on membrane-associated receptors. Here, we found that both estradiol and the G-protein–coupled estrogen receptor 1 (GPER1) specific agonist G1 rapidly induce brain-derived neurotrophic factor (BDNF) release, leading to transient stimulation of activity-regulated cytoskeleton-associated (Arc) protein translation and GluA1-containing AMPA receptor internalization in field CA3 of hippocampus. We also show that type-I metabotropic glutamate receptor (mGluR) activation does not induce Arc translation nor long-term depression (LTD) at the mossy fiber pathway, as opposed to its effects in CA1, and it only triggers LTD after GPER1 stimulation. Furthermore, this form of mGluR-dependent LTD is associated with ubiquitination and proteasome-mediated degradation of GluA1, and is prevented by proteasome inhibition. Overall, our study identifies a novel mechanism by which estrogen and BDNF regulate hippocampal synaptic plasticity in the adult brain.
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Affiliation(s)
- Victor Briz
- Graduate College of Biomedical Sciences, Western University of Health Sciences, Pomona, CA 91766 VIB Center for the Biology of Disease, Katholieke Universiteit Leuven, 3000 Leuven, Belgium
| | - Yan Liu
- Graduate College of Biomedical Sciences, Western University of Health Sciences, Pomona, CA 91766 College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, CA 91766
| | - Guoqi Zhu
- Graduate College of Biomedical Sciences, Western University of Health Sciences, Pomona, CA 91766 Key Laboratory of Xin'an Medicine, Ministry of Education, Anhui University of Traditional Chinese Medicine, Hefei 230038, China
| | - Xiaoning Bi
- College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, CA 91766
| | - Michel Baudry
- Graduate College of Biomedical Sciences, Western University of Health Sciences, Pomona, CA 91766
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Colciago A, Casati L, Negri-Cesi P, Celotti F. Learning and memory: Steroids and epigenetics. J Steroid Biochem Mol Biol 2015; 150:64-85. [PMID: 25766520 DOI: 10.1016/j.jsbmb.2015.02.008] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Revised: 02/11/2015] [Accepted: 02/12/2015] [Indexed: 12/19/2022]
Abstract
Memory formation and utilization is a complex process involving several brain structures in conjunction as the hippocampus, the amygdala and the adjacent cortical areas, usually defined as medial temporal lobe structures (MTL). The memory processes depend on the formation and modulation of synaptic connectivity affecting synaptic strength, synaptic plasticity and synaptic consolidation. The basic neurocognitive mechanisms of learning and memory are shortly recalled in the initial section of this paper. The effect of sex hormones (estrogens, androgens and progesterone) and of adrenocortical steroids on several aspects of memory processes are then analyzed on the basis of animal and human studies. A specific attention has been devoted to the different types of steroid receptors (membrane or nuclear) involved and on local metabolic transformations when required. The review is concluded by a short excursus on the steroid activated epigenetic mechanisms involved in memory formation.
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Affiliation(s)
- Alessandra Colciago
- Department of Pharmacological and Biomolecular Sciences, Section of Biomedicine and Endocrinology, Via Balzaretti 9, 20133 Milano, Italy
| | - Lavinia Casati
- Department of Medical Biotechnologies and Translational Medicine, Via Vanvitelli 32, 20129 Milano, Italy
| | - Paola Negri-Cesi
- Department of Pharmacological and Biomolecular Sciences, Section of Biomedicine and Endocrinology, Via Balzaretti 9, 20133 Milano, Italy
| | - Fabio Celotti
- Department of Pharmacological and Biomolecular Sciences, Section of Biomedicine and Endocrinology, Via Balzaretti 9, 20133 Milano, Italy
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Tozzi A, de Iure A, Tantucci M, Durante V, Quiroga-Varela A, Giampà C, Di Mauro M, Mazzocchetti P, Costa C, Di Filippo M, Grassi S, Pettorossi VE, Calabresi P. Endogenous 17β-estradiol is required for activity-dependent long-term potentiation in the striatum: interaction with the dopaminergic system. Front Cell Neurosci 2015; 9:192. [PMID: 26074768 PMCID: PMC4445326 DOI: 10.3389/fncel.2015.00192] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Accepted: 04/30/2015] [Indexed: 11/13/2022] Open
Abstract
17β-estradiol (E2), a neurosteroid synthesized by P450-aromatase (ARO), modulates various brain functions. We characterized the role of the locally synthesized E2 on striatal long-term synaptic plasticity and explored possible interactions between E2 receptors (ERs) and dopamine (DA) receptors in the dorsal striatum of adult male rats. Inhibition of E2 synthesis or antagonism of ERs prevented the induction of long-term potentiation (LTP) in both medium spiny neurons (MSNs) and cholinergic interneurons (ChIs). Activation of a D1-like DA receptor/cAMP/PKA-dependent pathway restored LTP. In MSNs exogenous E2 reversed the effect of ARO inhibition. Also antagonism of M1 muscarinic receptors prevented the D1-like receptor-mediated restoration of LTP confirming a role for ChIs in controlling the E2-mediated LTP of MSNs. A novel striatal interaction, occurring between ERs and D1-like receptors in both MSNs and ChIs, might be critical to regulate basal ganglia physiology and to compensate synaptic alterations in Parkinson’s disease.
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Affiliation(s)
- Alessandro Tozzi
- Department of Experimental Medicine, Section of Physiology and Biochemistry, University of Perugia Perugia, Italy ; Fondazione Santa Lucia, IRCCS Rome, Italy
| | - Antonio de Iure
- Clinica Neurologica, Dipartimento di Medicina, Università degli Studi di Perugia, Ospedale Santa Maria della Misericordia Perugia, Italy
| | - Michela Tantucci
- Clinica Neurologica, Dipartimento di Medicina, Università degli Studi di Perugia, Ospedale Santa Maria della Misericordia Perugia, Italy
| | - Valentina Durante
- Clinica Neurologica, Dipartimento di Medicina, Università degli Studi di Perugia, Ospedale Santa Maria della Misericordia Perugia, Italy
| | - Ana Quiroga-Varela
- Clinica Neurologica, Dipartimento di Medicina, Università degli Studi di Perugia, Ospedale Santa Maria della Misericordia Perugia, Italy
| | | | - Michela Di Mauro
- Department of Experimental Medicine, Section of Physiology and Biochemistry, University of Perugia Perugia, Italy
| | - Petra Mazzocchetti
- Clinica Neurologica, Dipartimento di Medicina, Università degli Studi di Perugia, Ospedale Santa Maria della Misericordia Perugia, Italy
| | - Cinzia Costa
- Clinica Neurologica, Dipartimento di Medicina, Università degli Studi di Perugia, Ospedale Santa Maria della Misericordia Perugia, Italy
| | - Massimiliano Di Filippo
- Clinica Neurologica, Dipartimento di Medicina, Università degli Studi di Perugia, Ospedale Santa Maria della Misericordia Perugia, Italy
| | - Silvarosa Grassi
- Department of Experimental Medicine, Section of Physiology and Biochemistry, University of Perugia Perugia, Italy
| | - Vito Enrico Pettorossi
- Department of Experimental Medicine, Section of Physiology and Biochemistry, University of Perugia Perugia, Italy
| | - Paolo Calabresi
- Fondazione Santa Lucia, IRCCS Rome, Italy ; Clinica Neurologica, Dipartimento di Medicina, Università degli Studi di Perugia, Ospedale Santa Maria della Misericordia Perugia, Italy
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Wefel JS, Kesler SR, Noll KR, Schagen SB. Clinical characteristics, pathophysiology, and management of noncentral nervous system cancer-related cognitive impairment in adults. CA Cancer J Clin 2015; 65:123-38. [PMID: 25483452 PMCID: PMC4355212 DOI: 10.3322/caac.21258] [Citation(s) in RCA: 320] [Impact Index Per Article: 35.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Answer questions and earn CME/CNE Over the past few decades, a body of research has emerged confirming what many adult patients with noncentral nervous system cancer have long reported-that cancer and its treatment are frequently associated with cancer-related cognitive impairment (CRCI). The severity of CRCI varies, and symptoms can emerge early or late in the disease course. Nonetheless, CRCI is typically mild to moderate in nature and primarily involves the domains of memory, attention, executive functioning, and processing speed. Animal models and novel neuroimaging techniques have begun to unravel the pathophysiologic mechanisms underlying CRCI, including the role of inflammatory cascades, direct neurotoxic effects, damage to progenitor cells, white matter abnormalities, and reduced functional connectivity, among others. Given the paucity of research on CRCI with other cancer populations, this review synthesizes the current literature with a deliberate focus on CRCI within the context of breast cancer. A hypothetical case-study approach is used to illustrate how CRCI often presents clinically and how current science can inform practice. While the literature regarding intervention for CRCI is nascent, behavioral and pharmacologic approaches are discussed.
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Affiliation(s)
- Jeffrey S. Wefel
- Associate Professor, Department of Neuro-Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX
- Corresponding author: Jeffrey S. Wefel, PhD, Department of Neuro-Oncology, The University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Boulevard, Unit 431, Houston, TX 77030;
| | - Shelli R. Kesler
- Associate Professor, Department of Neuro-Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - Kyle R. Noll
- Associate Professor, Department of Neuro-Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - Sanne B. Schagen
- Associate Professor, Division of Psychosocial Research and Epidemiology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
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39
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Hippocampal estradiol synthesis and its significance for hippocampal synaptic stability in male and female animals. Neuroscience 2014; 274:24-32. [DOI: 10.1016/j.neuroscience.2014.05.003] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Revised: 04/23/2014] [Accepted: 05/04/2014] [Indexed: 01/18/2023]
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40
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Zhang QG, Wang R, Tang H, Dong Y, Chan A, Sareddy GR, Vadlamudi RK, Brann DW. Brain-derived estrogen exerts anti-inflammatory and neuroprotective actions in the rat hippocampus. Mol Cell Endocrinol 2014; 389:84-91. [PMID: 24508637 PMCID: PMC4040313 DOI: 10.1016/j.mce.2013.12.019] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Revised: 12/30/2013] [Accepted: 12/31/2013] [Indexed: 12/26/2022]
Abstract
17β-estradiol (E2) has been implicated to play a critical role in neuroprotection, synaptic plasticity, and cognitive function. Classically, the role of gonadal-derived E2 in these events is well established, but the role of brain-derived E2 is less clear. To address this issue, we investigated the expression, localization, and modulation of aromatase and local E2 levels in the hippocampus following global cerebral ischemia (GCI) in adult ovariectomized rats. Immunohistochemistry (IHC) revealed that the hippocampal regions CA1, CA3 and dentate gyrus (DG) exhibited high levels of immunoreactive aromatase staining, with aromatase being co-localized primarily in neurons in non-ischemic animals. Following GCI, aromatase became highly expressed in GFAP-positive astrocytes in the hippocampal CA1 region at 2-3 days post GCI reperfusion. An ELISA for E2 and IHC for E2 confirmed the GCI-induced elevation of local E2 in the CA1 region and that the increase in local E2 occurred in astrocytes. Furthermore, central administration of aromatase antisense (AS) oligonucleotides, but not missense (MS) oligonucleotides, blocked the increase in aromatase and local E2 in astrocytes after GCI, and resulted in a significant increase in GCI-induced hippocampal CA1 region neuronal cell death and neuroinflammation. As a whole, these results suggest that brain-derived E2 exerts important neuroprotective and anti-inflammatory actions in the hippocampal CA1 region following GCI.
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Affiliation(s)
- Quan-Guang Zhang
- Institute of Molecular Medicine and Genetics, Medical College of Georgia at Georgia Regents University, Augusta, GA 30912, USA.
| | - Ruimin Wang
- Institute of Molecular Medicine and Genetics, Medical College of Georgia at Georgia Regents University, Augusta, GA 30912, USA; Neurobiology Institute of Medical Research Centre, Hebei United University, Tangshan, Hebei 063000, PR China
| | - Hui Tang
- Institute of Molecular Medicine and Genetics, Medical College of Georgia at Georgia Regents University, Augusta, GA 30912, USA; Neurobiology Institute of Medical Research Centre, Hebei United University, Tangshan, Hebei 063000, PR China
| | - Yan Dong
- Institute of Molecular Medicine and Genetics, Medical College of Georgia at Georgia Regents University, Augusta, GA 30912, USA
| | - Alice Chan
- Institute of Molecular Medicine and Genetics, Medical College of Georgia at Georgia Regents University, Augusta, GA 30912, USA
| | - Gangadhara Reddy Sareddy
- Department of Obstetrics and Gynecology, University of Texas Health Science Center, San Antonio, TX, USA
| | - Ratna K Vadlamudi
- Department of Obstetrics and Gynecology, University of Texas Health Science Center, San Antonio, TX, USA
| | - Darrell W Brann
- Institute of Molecular Medicine and Genetics, Medical College of Georgia at Georgia Regents University, Augusta, GA 30912, USA.
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41
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Bian C, Zhao Y, Guo Q, Xiong Y, Cai W, Zhang J. Aromatase inhibitor letrozole downregulates steroid receptor coactivator-1 in specific brain regions that primarily related to memory, neuroendocrine and integration. J Steroid Biochem Mol Biol 2014; 141:37-43. [PMID: 24434281 DOI: 10.1016/j.jsbmb.2013.12.020] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2013] [Revised: 11/26/2013] [Accepted: 12/27/2013] [Indexed: 01/15/2023]
Abstract
As one of the third generation of aromatase inhibitors, letrozole is a favored drug for the treatment of hormone receptor-positive breast cancer with some adverse effects on the nervous system, but the knowledge is limited and the results are controversial, the mechanism underlying its central action is also unclear. Accumulated evidences have demonstrated that estrogens derived from androgens by aromatase play profound roles in the brain through their receptors, which needs coactivator for the transcription regulation, among which steroid receptor coactivator-1 (SRC-1) has been shown to be multifunctional potentials in the brain, but whether it is regulated by letrozole is currently unknown. In this study, we examined letrozole regulation on SRC-1 expression in adult mice brain using immunohistochemistry. The results showed that letrozole induced dramatic decrease of SRC-1 in the medial septal, hippocampus, medial habenular nucleus, arcuate hypothalamic nucleus and superior colliculus (p<0.01). Significant decrease was detected in the dorsal lateral septal nucleus, bed nucleus of stria terminalis, ventral taenia tecta, dorsomedial and ventromedial hypothalamic nuclei, dorsomedial periaqueductal gray, superior paraolivary nucleus and pontine nucleus (p<0.05). In the hippocampus, levels of estradiol content, androgen receptor, estrogen receptor α and β also decreased significantly after letrozole injection. The above results demonstrated letrozole downregulation of SRC-1 in specific regions that are primarily related to learning and memory, cognition and mood, neuroendocrine as well as information integration, indicating that SRC-1 may be one important downstream central target of letrozole. Furthermore, these potential central adverse effects of letrozole should be taken into serious considerations.
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Affiliation(s)
- Chen Bian
- Department of Neurobiology, Chongqing Key Laboratory of Neurobiology, Third Military Medical University, Chongqing 400038, China
| | - Yangang Zhao
- Department of Neurobiology, Chongqing Key Laboratory of Neurobiology, Third Military Medical University, Chongqing 400038, China
| | - Qiang Guo
- Department of Neurobiology, Chongqing Key Laboratory of Neurobiology, Third Military Medical University, Chongqing 400038, China
| | - Ying Xiong
- Department of Neurobiology, Chongqing Key Laboratory of Neurobiology, Third Military Medical University, Chongqing 400038, China
| | - Wenqin Cai
- Department of Neurobiology, Chongqing Key Laboratory of Neurobiology, Third Military Medical University, Chongqing 400038, China.
| | - Jiqiang Zhang
- Department of Neurobiology, Chongqing Key Laboratory of Neurobiology, Third Military Medical University, Chongqing 400038, China.
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42
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Bian C, Zhu H, Zhao Y, Cai W, Zhang J. Intriguing roles of hippocampus-synthesized 17β-estradiol in the modulation of hippocampal synaptic plasticity. J Mol Neurosci 2014; 54:271-81. [PMID: 24729128 DOI: 10.1007/s12031-014-0285-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 03/06/2014] [Indexed: 10/25/2022]
Abstract
Accumulated studies have shown that 17β-estradiol (E2) can be de novo synthesized in the hippocampus, and its role in the regulation of hippocampal synaptic plasticity, which is the basis of learning and memory, has long been exploring. Steroidogenic enzymes (e.g., aromatase) that are essential to the hippocampus-synthesized synthesis of E2 have been detected in the hippocampus. Inhibition of E2 synthesis by aromatase inhibitors significantly reduces the density of hippocampal spine synapses, levels of some synaptic proteins such as spinopholin and synaptophysin. Moreover, the electrophysiological properties of hippocampal neurons are also changed in response to this inhibition. The influences of gonadal and hippocampal E2 on synaptic plasticity may exist some differences, since some reports showed that gonadal (or circulating) estrogens have no obvious effects in the modulation of hippocampal synaptic proteins as evidenced in some ovariectomized animals and postmenopausal women who suffered from Alzheimer's disease (AD). These evidences leads to a hypothesis that hippocampal E2 may play a more important role in modulation of synaptic plasticity than gonadal E2. The signaling pathways, whereby hippocampal E2 modulates synaptic plasticity, insist of classical chronic genomic pathway and rapid nongenomic pathway, which mediated by nonnuclear estrogen receptor (GPER) and/or nuclear or nonnuclear estrogen receptors, which require coactivators for their transcription activity. Among which steroid receptor coactivator-1 (SRC-1) is the predominant coactivator p160 family members in the brain. Several clues have shown that SRC-1 is expressed in hippocampus and is highly correlated with some key synaptic proteins developmentally or after orchidectomy but not ovariectomy, indicating SRC-1 may be regulated by hippocampus-synthesized E2 and profoundly involved in the mediation of hippocampal E2 regulation of hippocampal synaptic plasticity. Further studies about the exact roles of hippocampus-synthesized E2 and therefore SRC-1 are urgently needed in order to facilitate our understanding of hippocampal E2, which will be very important to the development of novel strategies of estrogen replacement therapy against neurodegenerative deficits such as Alzheimer's disease (AD).
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Affiliation(s)
- Chen Bian
- Department of Neurobiology, Chongqing Key Laboratory of Neurobiology, Third Military Medical University, Gaotanyan 30, Chongqing, 400038, China
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43
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Segarra AC, Torres-Díaz YM, Silva RD, Puig-Ramos A, Menéndez-Delmestre R, Rivera-Bermúdez JG, Amadeo W, Agosto-Rivera JL. Estrogen receptors mediate estradiol's effect on sensitization and CPP to cocaine in female rats: role of contextual cues. Horm Behav 2014; 65:77-87. [PMID: 24355096 PMCID: PMC3963412 DOI: 10.1016/j.yhbeh.2013.12.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Revised: 12/06/2013] [Accepted: 12/10/2013] [Indexed: 10/25/2022]
Abstract
Preclinical studies show that estradiol enhances sensitization to cocaine in females by mechanisms not fully understood. These studies consistently show that ovariectomized (OVX) rats exhibit little or no sensitization to cocaine compared to OVX rats administered estradiol. In this study we varied the dose of cocaine (10, 15, and 30mg/kg), the length of cocaine treatment (from 5 to 10days) and the context of cocaine injections to determine if these factors play a role on estradiol's effects on cocaine sensitization. Because OVX rats are hormonally compromised, they are not representative of the natural state of the animal, and thus the physiological context of these studies remains unclear. To address this issue, we blocked ERs in gonadally intact females by icv administration of the antiestrogen ICI-182,780. Varying the dose or length of exposure to cocaine does not alter estradiol's effect on cocaine sensitization. In contrast, a highly context-dependent sensitization protocol results in robust sensitization even in OVX rats. Interestingly, using this protocol, sensitization in OVX rats diminished with time, suggesting that estradiol is necessary for the maintenance of cocaine sensitization. Blocking brain ERs with ICI completely abolishes the development and expression of cocaine sensitization in gonadally intact female rats, even when tested in a highly context-dependent sensitization protocol. Given these findings, we propose that activation of brain ERs is required for the development and maintenance of sensitization and CPP.
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Affiliation(s)
- Annabell C Segarra
- University of Puerto Rico, Physiology Department, Medical Sciences Campus, P.O. Box 365067, San Juan 00936-5067, Puerto Rico.
| | - Yvonne M Torres-Díaz
- University of Puerto Rico, Physiology Department, Medical Sciences Campus, P.O. Box 365067, San Juan 00936-5067, Puerto Rico
| | - Richard D Silva
- Biology Department, Rio Piedras Campus, P.O. Box 23360, San Juan 00931, Puerto Rico
| | - Anabel Puig-Ramos
- University of Puerto Rico, Physiology Department, Medical Sciences Campus, P.O. Box 365067, San Juan 00936-5067, Puerto Rico
| | - Raissa Menéndez-Delmestre
- University of Puerto Rico, Physiology Department, Medical Sciences Campus, P.O. Box 365067, San Juan 00936-5067, Puerto Rico
| | | | - Waldo Amadeo
- University of Puerto Rico, Physiology Department, Medical Sciences Campus, P.O. Box 365067, San Juan 00936-5067, Puerto Rico
| | - José L Agosto-Rivera
- Biology Department, Rio Piedras Campus, P.O. Box 23360, San Juan 00931, Puerto Rico
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Pettorossi VE, Di Mauro M, Scarduzio M, Panichi R, Tozzi A, Calabresi P, Grassi S. Modulatory role of androgenic and estrogenic neurosteroids in determining the direction of synaptic plasticity in the CA1 hippocampal region of male rats. Physiol Rep 2013; 1:e00185. [PMID: 24744863 PMCID: PMC3970743 DOI: 10.1002/phy2.185] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Revised: 11/12/2013] [Accepted: 11/13/2013] [Indexed: 01/16/2023] Open
Abstract
Estrogenic and androgenic neurosteroids can rapidly modulate synaptic plasticity in the brain through interaction with membrane receptors for estrogens (ERs) and androgens (ARs). We used electrophysiological recordings in slices of young and adolescent male rats to explore the influence of sex neurosteroids on synaptic plasticity in the CA1 hippocampal region, by blocking ARs or ERs during induction of long‐term depression (LTD) and depotentiation (DP) by low‐frequency stimulation (LFS) and long‐term potentiation (LTP) by high‐frequency stimulation (HFS). We found that LTD and DP depend on ARs, while LTP on ERs in both age groups. Accordingly, the AR blocker flutamide affected induction of LTD reverting it into LTP, and prevented DP, while having no effect on HFS‐dependent LTP. Conversely, ER blockade with ICI 182,780 (ICI) markedly reduced LTP, but did not influence LTD and DP. However, the receptor blockade did not affect the maintenance of either LTD or LTP. Moreover, we found that similar to LTP and LTD induced in control condition, the LTP unveiled by flutamide during LFS and residual LTP induced by HFS under ICI depended on N‐methyl‐d aspartate receptor (NMDAR) activation. Furthermore, as the synaptic paired‐pulse facilitation (PPF) was not affected by either AR or ER blockade, we suggest that sex neurosteroids act primarily at a postsynaptic level. This study demonstrates for the first time the crucial role of estrogenic and androgenic neurosteroids in determining the sign of hippocampal synaptic plasticity in male rat and the activity‐dependent recruitment of androgenic and estrogenic pathways leading to LTD and LTP, respectively. This study shows a crucial and opposite role of estrogenic and androgenic neurosteroids in guiding the direction of synaptic plasticity in the hippocampus CA1 region of male rat, through activation of their specific receptors. In fact, by using selective antagonists for estrogen receptors (ICI 182,730) or androgen receptors (flutamide), we show that long‐term potentiation (LTP) induced by high‐frequency stimulation (HFS) depends on estrogenic signals, while long‐term depression (LTD) and depotentiation induced by low‐frequency stimulation (LFS) require activation of androgenic pathway. We suggest that different stimulation frequencies may lead to LTD or LTP depending on activation of specific neurosteroid pathway.
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Affiliation(s)
- Vito Enrico Pettorossi
- Dipartimento di Medicina Interna, Sezione di Fisiologia Umana, Università di Perugia, Polo Unico Sant'Andrea delle Fratte, Via Gambuli, Perugia, 106156, Italy
| | - Michela Di Mauro
- Dipartimento di Medicina Interna, Sezione di Fisiologia Umana, Università di Perugia, Polo Unico Sant'Andrea delle Fratte, Via Gambuli, Perugia, 106156, Italy
| | - Mariangela Scarduzio
- Dipartimento di Medicina Interna, Sezione di Fisiologia Umana, Università di Perugia, Polo Unico Sant'Andrea delle Fratte, Via Gambuli, Perugia, 106156, Italy
| | - Roberto Panichi
- Dipartimento di Medicina Interna, Sezione di Fisiologia Umana, Università di Perugia, Polo Unico Sant'Andrea delle Fratte, Via Gambuli, Perugia, 106156, Italy
| | - Alessandro Tozzi
- Clinica Neurologica, Ospedale S. Maria della Misericordia, Università di Perugia, Perugia, 06156, Italy ; Fondazione Santa Lucia, I.R.C.C.S, Roma, 00143, Italy
| | - Paolo Calabresi
- Clinica Neurologica, Ospedale S. Maria della Misericordia, Università di Perugia, Perugia, 06156, Italy ; Fondazione Santa Lucia, I.R.C.C.S, Roma, 00143, Italy
| | - Silvarosa Grassi
- Dipartimento di Medicina Interna, Sezione di Fisiologia Umana, Università di Perugia, Polo Unico Sant'Andrea delle Fratte, Via Gambuli, Perugia, 106156, Italy
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Scarduzio M, Panichi R, Pettorossi VE, Grassi S. Synaptic long-term potentiation and depression in the rat medial vestibular nuclei depend on neural activation of estrogenic and androgenic signals. PLoS One 2013; 8:e80792. [PMID: 24265837 PMCID: PMC3827183 DOI: 10.1371/journal.pone.0080792] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Accepted: 10/07/2013] [Indexed: 11/18/2022] Open
Abstract
Estrogenic and androgenic steroids can be synthesised in the brain and rapidly modulate synaptic transmission and plasticity through direct interaction with membrane receptors for estrogens (ERs) and androgens (ARs). We used whole cell patch clamp recordings in brainstem slices of male rats to explore the influence of ER and AR activation and local synthesis of 17β-estradiol (E2) and 5α-dihydrotestosterone (DHT) on the long-term synaptic changes induced in the neurons of the medial vestibular nucleus (MVN). Long-term depression (LTD) and long-term potentiation (LTP) caused by different patterns of high frequency stimulation (HFS) of the primary vestibular afferents were assayed under the blockade of ARs and ERs or in the presence of inhibitors for enzymes synthesizing DHT (5α-reductase) and E2 (P450-aromatase) from testosterone (T). We found that LTD is mediated by interaction of locally produced androgens with ARs and LTP by interaction of locally synthesized E2 with ERs. In fact, the AR block with flutamide prevented LTD while did not affect LTP, and the blockade of ERs with ICI 182,780 abolished LTP without influencing LTD. Moreover, the block of P450-aromatase with letrozole not only prevented the LTP induction, but inverted LTP into LTD. This LTD is likely due to the local activation of androgens, since it was abolished under blockade of ARs. Conversely, LTD was still induced in the presence of finasteride the inhibitor of 5α-reductase demonstrating that T is able to activate ARs and induce LTD even when DHT is not synthesized. This study demonstrates a key and opposite role of sex neurosteroids in the long-term synaptic changes of the MVN with a specific role of T-DHT for LTD and of E2 for LTP. Moreover, it suggests that different stimulation patterns can lead to LTD or LTP by specifically activating the enzymes involved in the synthesis of androgenic or estrogenic neurosteroids.
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Affiliation(s)
- Mariangela Scarduzio
- Dipartimento di Medicina Interna, Sezione di Fisiologia Umana, Facoltà di Medicina e Chirurgia, Università di Perugia, Perugia, Italy
| | - Roberto Panichi
- Dipartimento di Medicina Interna, Sezione di Fisiologia Umana, Facoltà di Medicina e Chirurgia, Università di Perugia, Perugia, Italy
| | - Vito Enrico Pettorossi
- Dipartimento di Medicina Interna, Sezione di Fisiologia Umana, Facoltà di Medicina e Chirurgia, Università di Perugia, Perugia, Italy
| | - Silvarosa Grassi
- Dipartimento di Medicina Interna, Sezione di Fisiologia Umana, Facoltà di Medicina e Chirurgia, Università di Perugia, Perugia, Italy
- * E-mail:
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46
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Grassi S, Scarduzio M, Panichi R, Dall'Aglio C, Boiti C, Pettorossi VE. Opposite long-term synaptic effects of 17β-estradiol and 5α-dihydrotestosterone and localization of their receptors in the medial vestibular nucleus of rats. Brain Res Bull 2013; 97:1-7. [PMID: 23701910 DOI: 10.1016/j.brainresbull.2013.05.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Revised: 05/09/2013] [Accepted: 05/13/2013] [Indexed: 10/26/2022]
Abstract
In brainstem slices of male rats, we examined in single neurons of the medial vestibular nucleus (MVN) the effect of exogenous administration of estrogenic (17β-estradiol, E2) and androgenic (5α-dihydrotestosterone, DHT) steroids on the synaptic response to vestibular afferent stimulation. By whole cell patch clamp recordings we showed that E2 induced synaptic long-term potentiation (LTP) that was cancelled by the subsequent administration of DHT. Conversely, DHT induced synaptic long-term depression (LTD) that was partially reversed by E2. The electrophysiological findings were supported by immunohistochemical analysis showing the presence of estrogen (ER: α and β) and androgen receptors (AR) in the MVN neurons. We found that a large number of neurons were immunoreactive for ERα, ERβ, and AR and most of them co-localized ERβ and AR. We also showed the presence of P450-aromatase (ARO) in the MVN neurons, clearly proving that E2 can be locally synthesized in the MVN. On the whole, these results demonstrate a role of estrogenic and androgenic signals in modulating vestibular synaptic plasticity and suggest that the enhancement or depression of vestibular synaptic response may depend on the local conversion of T into E2 or DHT.
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Affiliation(s)
- Silvarosa Grassi
- Dipartimento di Medicina Interna, Sezione di Fisiologia Umana, Università di Perugia, Via del Giochetto, I-06126 Perugia, Italy.
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Testosterone depletion in adult male rats increases mossy fiber transmission, LTP, and sprouting in area CA3 of hippocampus. J Neurosci 2013; 33:2338-55. [PMID: 23392664 DOI: 10.1523/jneurosci.3857-12.2013] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Androgens have dramatic effects on neuronal structure and function in hippocampus. However, androgen depletion does not always lead to hippocampal impairment. To address this apparent paradox, we evaluated the hippocampus of adult male rats after gonadectomy (Gdx) or sham surgery. Surprisingly, Gdx rats showed increased synaptic transmission and long-term potentiation of the mossy fiber (MF) pathway. Gdx rats also exhibited increased excitability and MF sprouting. We then addressed the possible underlying mechanisms and found that Gdx induced a long-lasting upregulation of MF BDNF immunoreactivity. Antagonism of Trk receptors, which bind neurotrophins, such as BDNF, reversed the increase in MF transmission, excitability, and long-term potentiation in Gdx rats, but there were no effects of Trk antagonism in sham controls. To determine which androgens were responsible, the effects of testosterone metabolites DHT and 5α-androstane-3α,17β-diol were examined. Exposure of slices to 50 nm DHT decreased the effects of Gdx on MF transmission, but 50 nm 5α-androstane-3α,17β-diol had no effect. Remarkably, there was no effect of DHT in control males. The data suggest that a Trk- and androgen receptor-sensitive form of MF transmission and synaptic plasticity emerges after Gdx. We suggest that androgens may normally be important in area CA3 to prevent hyperexcitability and aberrant axon outgrowth but limit MF synaptic transmission and some forms of plasticity. The results also suggest a potential explanation for the maintenance of hippocampal-dependent cognitive function after androgen depletion: a reduction in androgens may lead to compensatory upregulation of MF transmission and plasticity.
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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: 65] [Impact Index Per Article: 5.4] [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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Inagaki T, Kaneko N, Zukin RS, Castillo PE, Etgen AM. Estradiol attenuates ischemia-induced death of hippocampal neurons and enhances synaptic transmission in aged, long-term hormone-deprived female rats. PLoS One 2012; 7:e38018. [PMID: 22675505 PMCID: PMC3366987 DOI: 10.1371/journal.pone.0038018] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2012] [Accepted: 05/02/2012] [Indexed: 11/18/2022] Open
Abstract
Background Transient global forebrain ischemia causes selective, delayed death of hippocampal CA1 pyramidal neurons, and the ovarian hormone 17β-estradiol (E2) reduces neuronal loss in young and middle-aged females. The neuroprotective efficacy of E2 after a prolonged period of hormone deprivation is controversial, and few studies examine this issue in aged animals given E2 treatment after induction of ischemia. Methodology/Principal Findings The present study investigated the neuroprotective effects of E2 administered immediately after global ischemia in aged female rats (15–18 months) after 6 months of hormone deprivation. We also used electrophysiological methods to assess whether CA1 synapses in the aging hippocampus remain responsive to E2 after prolonged hormone withdrawal. Animals were ovariohysterectomized and underwent 10 min global ischemia 6 months later. A single dose of E2 (2.25 µg) infused intraventricularly after reperfusion significantly increased cell survival, with 45% of CA1 neurons surviving vs 15% in controls. Ischemia also induced moderate loss of CA3/CA4 pyramidal cells. Bath application of 1 nM E2 onto brain slices derived from non-ischemic aged females after 6 months of hormone withdrawal significantly enhanced excitatory transmission at CA1 synapses evoked by Schaffer collateral stimulation, and normal long-term potentiation (LTP) was induced. The magnitude of LTP and of E2 enhancement of field excitatory postsynaptic potentials was indistinguishable from that recorded in slices from young rats. Conclusions/Significance The data demonstrate that 1) acute post-ischemic infusion of E2 into the brain ventricles is neuroprotective in aged rats after 6 months of hormone deprivation; and 2) E2 enhances synaptic transmission in CA1 pyramidal neurons of aged long-term hormone deprived females. These findings provide evidence that the aging hippocampus remains responsive to E2 administered either in vivo or in vitro even after prolonged periods of hormone withdrawal.
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Affiliation(s)
- Tomoko Inagaki
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Naoki Kaneko
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - R. Suzanne Zukin
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Pablo E. Castillo
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Anne M. Etgen
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, United States of America
- * E-mail:
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Grassi S, Frondaroli A, Scarduzio M, Dieni CV, Brecchia G, Boiti C, Pettorossi VE. Influence of sex and estrous cycle on synaptic responses of the medial vestibular nuclei in rats: role of circulating 17β-estradiol. Brain Res Bull 2011; 87:319-27. [PMID: 22127323 DOI: 10.1016/j.brainresbull.2011.11.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2011] [Revised: 11/08/2011] [Accepted: 11/15/2011] [Indexed: 11/30/2022]
Abstract
We investigated the possible influence of sex and estrous cycle on the synaptic responses of neurons in the medial vestibular nucleus (MVN) and their long-term modifications. In brain stem slices of male and female rats during proestrus (PE) and diestrus (DE), we evaluated the field potential evoked in the MVN by vestibular afferent stimulation. Here we find that in PE females the field potential had a lower threshold and higher amplitude than in DE females and in males and also that the stimulus-response curve was shifted to the left. Such difference is related to the level and cyclic fluctuation of circulating 17β-estradiol (E(2)). This is supported by the exogenous administration of E(2) in DE females and males, with low levels of circulating E(2) that enhanced the field potential amplitude to values close to those of PE females. Sex and estrous cycle also influence the MVN synaptic plasticity. This has been shown by investigating the effect of testosterone (T) on the induction of long-term effects, since T is the precursor for the neural synthesis of E(2) (estrogenic pathway), which is involved in the induction of fast long-term potentiation (LTP), or of 5α-dihydrotestosterone (DHT, androgenic pathway) which mediates slow LTP and long-term depression (LTD). We found that T mostly induced LTD in PE females and no effect in DE females, while it only provoked fast LTP in males. We suggest that high level of circulating E(2) may interfere with the conversion of T, by inhibiting the neural estrogenic pathway and facilitating the androgenic one. On the whole these results demonstrate an influence of circulating E(2) on vestibular synaptic transmission and plasticity that in some cases may contribute to the sex and menstrual cycle dependence of symptoms in human vestibular pathology.
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Affiliation(s)
- Silvarosa Grassi
- Dipartimento di Medicina Interna, Sezione di Fisiologia Umana, Università di Perugia, Via del Giochetto, I-06126 Perugia, Italy.
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