1
|
Mitchnick KA, Nicholson K, Wideman C, Jardine K, Jamieson-Williams R, Creighton SD, Lacoursiere A, Milite C, Castellano S, Sbardella G, MacLusky NJ, Choleris E, Winters BD. The Lysine Acetyltransferase PCAF Functionally Interacts with Estrogen Receptor Alpha in the Hippocampus of Gonadally Intact Male-But Not Female-Rats to Enhance Short-Term Memory. J Neurosci 2024; 44:e1574232024. [PMID: 39138001 PMCID: PMC11376336 DOI: 10.1523/jneurosci.1574-23.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2023] [Revised: 07/05/2024] [Accepted: 07/15/2024] [Indexed: 08/15/2024] Open
Abstract
Acetylation of histone proteins by histone acetyltransferases (HATs), and the resultant change in gene expression, is a well-established mechanism necessary for long-term memory (LTM) consolidation, which is not required for short-term memory (STM). However, we previously demonstrated that the HAT p300/CBP-associated factor (PCAF) also influences hippocampus (HPC)-dependent STM in male rats. In addition to their epigenetic activity, HATs acetylate nonhistone proteins involved in nongenomic cellular processes, such as estrogen receptors (ERs). Given that ERs have rapid, nongenomic effects on HPC-dependent STM, we investigated the potential interaction between ERs and PCAF for STM mediated by the dorsal hippocampus (dHPC). Using a series of pharmacological agents administered directly into the dHPC, we reveal a functional interaction between PCAF and ERα in the facilitation of short-term object-in-place memory in male but not female rats. This interaction was specific to ERα, while ERβ agonism did not enhance STM. It was further specific to dHPC STM, as the effect was not present in the dHPC for LTM or in the perirhinal cortex. Further, while STM required local (i.e., dHPC) estrogen synthesis, the facilitatory interaction effect appeared independent of estrogens. Finally, western blot analyses demonstrated that PCAF activation in the dHPC rapidly (5 min) activated downstream estrogen-related cell signaling kinases (c-Jun N-terminal kinase and extracellular signal-related kinase). Collectively, these findings indicate that PCAF, which is typically implicated in LTM through epigenetic processes, also influences STM in the dHPC, possibly via nongenomic ER activity. Critically, this novel PCAF-ER interaction might exist as a male-specific mechanism supporting STM.
Collapse
Affiliation(s)
- Krista A Mitchnick
- Department of Psychology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
- Collaborative Neuroscience Program, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Kate Nicholson
- Collaborative Neuroscience Program, University of Guelph, Guelph, Ontario N1G 2W1, Canada
- Department of Biomedical Sciences, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Cassidy Wideman
- Department of Psychology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
- Collaborative Neuroscience Program, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Kristen Jardine
- Department of Psychology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
- Collaborative Neuroscience Program, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | | | - Samantha D Creighton
- Department of Psychology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
- Collaborative Neuroscience Program, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Allison Lacoursiere
- Department of Psychology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Ciro Milite
- Department of Pharmacy, Epigenetic Med Chem Lab, University of Salerno, Fisciano I-84084, Italy
| | - Sabrina Castellano
- Department of Pharmacy, Epigenetic Med Chem Lab, University of Salerno, Fisciano I-84084, Italy
| | - Gianluca Sbardella
- Department of Pharmacy, Epigenetic Med Chem Lab, University of Salerno, Fisciano I-84084, Italy
| | - Neil J MacLusky
- Collaborative Neuroscience Program, University of Guelph, Guelph, Ontario N1G 2W1, Canada
- Department of Biomedical Sciences, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Elena Choleris
- Department of Psychology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
- Collaborative Neuroscience Program, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Boyer D Winters
- Department of Psychology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
- Collaborative Neuroscience Program, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| |
Collapse
|
2
|
Mamczarz J, Lane M, Merchenthaler I. Letrozole delays acquisition of water maze task in female BALB/c mice: Possible involvement of anxiety. Horm Behav 2024; 162:105524. [PMID: 38513526 DOI: 10.1016/j.yhbeh.2024.105524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 02/25/2024] [Accepted: 02/28/2024] [Indexed: 03/23/2024]
Abstract
Letrozole, an aromatase inhibitor preventing estrogen synthesis from testosterone, is used as an adjuvant therapy in estrogen receptor-positive breast cancer patients. However, like other aromatase inhibitors, it induces many side effects, including impaired cognition. Despite its negative effect in humans, results from animal models are inconsistent and suggest that letrozole can either impair or improve cognition. Here, we studied the effects of chronic letrozole treatment on cognitive behavior of adult female BALB/c mice, a relevant animal model for breast cancer studies, to develop an appropriate animal model aimed at testing therapies to mitigate side effects of letrozole. In Morris water maze, letrozole 0.1 mg/kg impaired reference learning and memory. Interestingly, most of the letrozole 0.1 mg/kg-treated mice were able to learn the new platform position in reversal training and performed similar to control mice in a reversal probe test. Results of the reversal test suggest that letrozole did not completely disrupt spatial navigation, but rather delayed acquisition of spatial information. The delay might be related to increased anxiety as suggested by increased thigmotactic behavior during the reference memory training. The learning impairment was water maze-specific since we did not observe impairment in other spatial tasks such as in Y-maze or object location test. In contrast, the dose of 0.3 mg/kg did not have effect on water maze learning and facilitated locomotor habituation and recognition in novel object recognition test. The current study shows that letrozole dose-dependently modulates behavioral response and that its effects are task-dependent.
Collapse
Affiliation(s)
- Jacek Mamczarz
- Division of Translational Toxicology, Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, MD 21201, United States of America.
| | - Malcolm Lane
- Department of Anatomy & Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, United States of America
| | - Istvan Merchenthaler
- Division of Translational Toxicology, Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, MD 21201, United States of America; Department of Anatomy & Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, United States of America
| |
Collapse
|
3
|
Hernández-Vivanco A, Cano-Adamuz N, Sánchez-Aguilera A, González-Alonso A, Rodríguez-Fernández A, Azcoitia Í, de la Prida LM, Méndez P. Sex-specific regulation of inhibition and network activity by local aromatase in the mouse hippocampus. Nat Commun 2022; 13:3913. [PMID: 35798748 PMCID: PMC9262915 DOI: 10.1038/s41467-022-31635-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 06/27/2022] [Indexed: 11/15/2022] Open
Abstract
Cognitive function relies on a balanced interplay between excitatory and inhibitory neurons (INs), but the impact of estradiol on IN function is not fully understood. Here, we characterize the regulation of hippocampal INs by aromatase, the enzyme responsible for estradiol synthesis, using a combination of molecular, genetic, functional and behavioral tools. The results show that CA1 parvalbumin-expressing INs (PV-INs) contribute to brain estradiol synthesis. Brain aromatase regulates synaptic inhibition through a mechanism that involves modification of perineuronal nets enwrapping PV-INs. In the female brain, aromatase modulates PV-INs activity, the dynamics of network oscillations and hippocampal-dependent memory. Aromatase regulation of PV-INs and inhibitory synapses is determined by the gonads and independent of sex chromosomes. These results suggest PV-INs are mediators of estrogenic regulation of behaviorally-relevant activity. Using a combination of molecular, genetic, functional and behavioural tools, this study describes the impact of brain synthesized estrogen in inhibitory neuronal function, network oscillations and hippocampal dependent memory.
Collapse
Affiliation(s)
| | | | - Alberto Sánchez-Aguilera
- Instituto Cajal (CSIC), Av Dr. Arce 37, 28002, Madrid, Spain.,Department of Physiology, Faculty of Medicine, Universidad Complutense de Madrid IdISSC, Avda Complutense s/n, 28040, Madrid, Spain
| | | | | | - Íñigo Azcoitia
- Department of Cell Biology, Universidad Complutense de Madrid, C José Antonio Nováis 12, 28040, Madrid, Spain.,Centro de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable (CIBERFES), Instituto de Salud Carlos III, Madrid, Spain
| | | | - Pablo Méndez
- Instituto Cajal (CSIC), Av Dr. Arce 37, 28002, Madrid, Spain.
| |
Collapse
|
4
|
Scene memory and hippocampal volume in middle-aged women with early hormone loss. Neurobiol Aging 2022; 117:97-106. [DOI: 10.1016/j.neurobiolaging.2022.05.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 04/20/2022] [Accepted: 05/06/2022] [Indexed: 11/22/2022]
|
5
|
Uhl M, Schmeisser MJ, Schumann S. The Sexual Dimorphic Synapse: From Spine Density to Molecular Composition. Front Mol Neurosci 2022; 15:818390. [PMID: 35250477 PMCID: PMC8894598 DOI: 10.3389/fnmol.2022.818390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 01/20/2022] [Indexed: 11/13/2022] Open
Abstract
A synaptic sexual dimorphism is relevant in the context of multiple neurodevelopmental, neurodegenerative, and neuropsychiatric disorders. Many of these disorders show a different prevalence and progression in woman and man. A similar variance is also present in corresponding animal models. To understand and characterize this dimorphism in pathologies it is important to first understand sex differences in unaffected individuals. Therefore, sexual differences have been studied since 1788, first focusing on brain weight, size, and volume. But as these measures are not directly related to brain function, the investigation of sexual dimorphism also expanded to other organizational levels of the brain. This review is focused on sexual dimorphism at the synaptic level, as these specialized structures are the smallest functional units of the brain, determining cell communication, connectivity, and plasticity. Multiple differences between males and females can be found on the levels of spine density, synaptic morphology, and molecular synapse composition. These differences support the importance of sex-disaggregated data. The specificity of changes to a particular brain region or circuit might support the idea of a mosaic brain, in which each tile individually lies on a continuum from masculinization to feminization. Moreover, synapses can be seen as the smallest tiles of the mosaic determining the classification of larger areas.
Collapse
Affiliation(s)
- Mara Uhl
- Institute for Microscopic Anatomy and Neurobiology, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
- Focus Program Translational Neurosciences, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Michael J. Schmeisser
- Institute for Microscopic Anatomy and Neurobiology, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
- Focus Program Translational Neurosciences, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
- *Correspondence: Michael J. Schmeisser,
| | - Sven Schumann
- Institute for Microscopic Anatomy and Neurobiology, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
- Sven Schumann,
| |
Collapse
|
6
|
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.
Collapse
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
| |
Collapse
|
7
|
Azcoitia I, Mendez P, Garcia-Segura LM. Aromatase in the Human Brain. ANDROGENS: CLINICAL RESEARCH AND THERAPEUTICS 2021; 2:189-202. [PMID: 35024691 PMCID: PMC8744447 DOI: 10.1089/andro.2021.0007] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Accepted: 06/20/2021] [Indexed: 11/30/2022]
Abstract
The aromatase cytochrome P450 (P450arom) enzyme, or estrogen synthase, which is coded by the CYP19A1 gene, is widely expressed in a subpopulation of excitatory and inhibitory neurons, astrocytes, and other cell types in the human brain. Experimental studies in laboratory animals indicate a prominent role of brain aromatization of androgens to estrogens in regulating different brain functions. However, the consequences of aromatase expression in the human brain remain poorly understood. Here, we summarize the current knowledge about aromatase expression in the human brain, abundant in the thalamus, amygdala, hypothalamus, cortex, and hippocampus and discuss its role in the regulation of sensory integration, body homeostasis, social behavior, cognition, language, and integrative functions. Since brain aromatase is affected by neurodegenerative conditions and may participate in sex-specific manifestations of autism spectrum disorders, major depressive disorder, multiple sclerosis, stroke, and Alzheimer's disease, we discuss future avenues for research and potential clinical and therapeutic implications of the expression of aromatase in the human brain.
Collapse
Affiliation(s)
- Iñigo Azcoitia
- Department of Cell Biology, Faculty of Biology, Universidad Complutense de Madrid and Centro de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable (CIBERFES), Instituto de Salud Carlos III, Madrid, Spain
| | - Pablo Mendez
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
| | - Luis M. Garcia-Segura
- Department of Cell Biology, Faculty of Biology, Universidad Complutense de Madrid and Centro de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable (CIBERFES), Instituto de Salud Carlos III, Madrid, Spain
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
| |
Collapse
|
8
|
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: 53] [Impact Index Per Article: 17.7] [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.
Collapse
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.
| |
Collapse
|
9
|
Sommer T, Schröter R, Bayer J. Probing emotional recognition memory: how different response formats affect response behaviour. Memory 2021; 29:1216-1231. [PMID: 34486950 DOI: 10.1080/09658211.2021.1974049] [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: 10/20/2022]
Abstract
Receiver-operating characteristic curves from confidence ratings and remember/know (R/K) judgments are often used to estimate the contribution of familiarity and recollection to recognition memory. Both coming with specific advantages and disadvantages, which could be reduced by their combination. Little is known how the combination of both methods impacts response behaviour. This could be particularly important for emotional memory research, which is susceptible to variation in meta-mnemonic processes. We obtained reference performance indices from the two methods, instructing individuals to give confidence ratings or R/K judgments in one step. Against these, we contrasted R/K judgments in a two-step format and two combined formats, confidence ratings followed by R/K judgments and vice versa. Regarding reference formats, confidence ratings resulted in more liberal response criteria and false alarm rates than R/K judgments. Two-step R/K judgments and confidence ratings followed by R/K judgments resulted in patterns similar to one-step R/K judgments. Reversing the order resulted in more liberal response biases, higher hit and false alarms rates. Recollection and familiarity were unaffected by response formats. Valence effects did not vary with response formats. The present results suggest that confidence ratings followed by R/K judgments provide the advantages of both without biasing response behaviour.
Collapse
Affiliation(s)
- Tobias Sommer
- Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Romy Schröter
- Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Janine Bayer
- Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| |
Collapse
|
10
|
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.
Collapse
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.
| |
Collapse
|
11
|
Meng L, Liu J, Wang C, Ouyang Z, Kuang J, Pang Q, Fan R. Sex-specific oxidative damage effects induced by BPA and its analogs on primary hippocampal neurons attenuated by EGCG. CHEMOSPHERE 2021; 264:128450. [PMID: 33007573 DOI: 10.1016/j.chemosphere.2020.128450] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 08/31/2020] [Accepted: 09/24/2020] [Indexed: 06/11/2023]
Abstract
BPA analogs, including bisphenol S (BPS) and bisphenol B (BPB), have been used to replace BPA since it was banned to be added. To investigate whether BPA and its analogs cause oxidative damage effects on primary hippocampal neurons of rats, reactive oxygen species (ROS), malondialdehyde (MDA), superoxide dismutase (SOD), mitochondrial membrane potential (MMP), apoptosis and cell viability assays were conducted after hippocampal neurons exposure to different concentrations of BPA, BPS, and BPB (1, 10, 100 nM and 1, 10, 100 μM). Moreover, the effects of EGCG (5 and 6 μM for male and female, respectively) added on neurons exposed to BPA were assessed. Results showed that 24 h exposure to these bisphenols (BPs) could increase the levels of ROS and contents of MDA, but reduce the activity of SOD significantly. A decline of cell viabilities accompanied with the increasing of apoptosis rates was observed after 7 d exposure to BPs and the reduction of MMP was also observed after 7 d exposure to BPA. Interestingly, BPS has the lower toxicity to hippocampal neurons compared with BPA and BPB. Non-monotonic dose-effect relationships between the concentrations of BPs and the cytotoxic effects were observed, and the effects of BPs on male hippocampal neurons are greater than those of female ones in general. While EGCG can protect neurons free of oxidative damages. In conclusion, the results suggest that BPs may induce sex-specific neurotoxic effects involving oxidative stress, which can be attenuated by EGCG, and males are more sensitive to BPs than females.
Collapse
Affiliation(s)
- Lingxue Meng
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, School of Life Sciences, South China Normal University, Guangzhou, 510631, China
| | - Jian Liu
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, School of Life Sciences, South China Normal University, Guangzhou, 510631, China
| | - Congcong Wang
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, School of Life Sciences, South China Normal University, Guangzhou, 510631, China
| | - Zedong Ouyang
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, School of Life Sciences, South China Normal University, Guangzhou, 510631, China
| | - Jiahua Kuang
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, School of Life Sciences, South China Normal University, Guangzhou, 510631, China
| | - Qihua Pang
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, School of Life Sciences, South China Normal University, Guangzhou, 510631, China.
| | - Ruifang Fan
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, School of Life Sciences, South China Normal University, Guangzhou, 510631, China; Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety, South China Normal University, Guangzhou, 510006, China.
| |
Collapse
|
12
|
Baumgartner NE, Daniel JM. Estrogen receptor α: a critical role in successful female cognitive aging. Climacteric 2021; 24:333-339. [PMID: 33522313 DOI: 10.1080/13697137.2021.1875426] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Due to potential health risks, current recommendations are that individuals who wish to use hormone therapy to treat menopausal symptoms do so for the shortest period of time possible. In our investigation into how short-term use of estrogens in midlife following loss of ovarian function exerts long-term effects on female cognitive aging in rodents, we discovered a link between the ability of previous exposure to estradiol to enhance memory in the long term and its ability to increase estrogen receptor α (ERα) levels in the hippocampus, a brain area important for memory. Follow-up studies in model systems implicate a role for ERα in enhanced cognitive function independent of ovarian or exogenously administered estrogens. Results are consistent with clinical studies in which brain ERα levels in older women and men are related to cognitive functioning and risk of cognitive decline is associated with polymorphisms in the gene that transcribes ERα. Research in preclinical models reveals mechanisms through which ERα can be activated and affect cognition in the absence of ovarian estrogens, including ligand-independent activation via insulin-like growth factor-1 signaling and activation by brain-derived neuroestrogens. This report reviews preclinical and clinical data that collectively point to the importance of ERα in cognition and highlights the need to differentiate the role of estrogen receptors from their classical ligands as we seek approaches to facilitate successful cognitive aging.
Collapse
Affiliation(s)
- N E Baumgartner
- Neuroscience Program, Tulane University, New Orleans, LA, USA.,Brain Institute, Tulane University, New Orleans, LA, USA
| | - J M Daniel
- Neuroscience Program, Tulane University, New Orleans, LA, USA.,Brain Institute, Tulane University, New Orleans, LA, USA.,Department of Psychology, Tulane University, New Orleans, LA, USA
| |
Collapse
|
13
|
Abstract
Letrozole, an aromatase inhibitor that blocks estrogen synthesis by inhibiting the final step of the estrogen biosynthetic pathway, has been used in the applications of a wide range of infertility settings. It has been more than 20 years since the initial clinical trial of letrozole for ovulation induction. In light of the accumulating clinical and basic evidence, the efficacy and safety of letrozole have been identified. This mini review focuses on our current knowledge of the applications and mechanisms of letrozole for female infertility and various questions are put forward about how letrozole could be more effectively used.
Collapse
|
14
|
Meeker TJ, Veldhuijzen DS, Keaser ML, Gullapalli RP, Greenspan JD. Menstrual Cycle Variations in Gray Matter Volume, White Matter Volume and Functional Connectivity: Critical Impact on Parietal Lobe. Front Neurosci 2020; 14:594588. [PMID: 33414702 PMCID: PMC7783210 DOI: 10.3389/fnins.2020.594588] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Accepted: 11/25/2020] [Indexed: 12/13/2022] Open
Abstract
The role of gonadal hormones in neural plasticity remains unclear. This study aimed to examine the effects of naturally fluctuating hormone levels over the menstrual cycle in healthy females. Gray matter, functional connectivity (FC) and white matter changes over the cycle were assessed by using functional magnetic resonance imaging (fMRI), resting state fMRI, and structural MRIs, respectively, and associated with serum gonadal hormone levels. Moreover, electrocutaneous sensitivity was evaluated in 14 women in four phases of their menstrual cycle (menstrual, follicular, ovulatory, and luteal). Electrocutaneous sensitivity was greater during follicular compared to menstrual phase. Additionally, pain unpleasantness was lower in follicular phase than other phases while pain intensity ratings did not change over the cycle. Significant variations in cycle phase effects on gray matter volume were found in the left inferior parietal lobule (IPL) using voxel-based morphometry. Subsequent Freesurfer analysis revealed greater thickness of left IPL during the menstrual phase when compared to other phases. Also, white matter volume fluctuated across phases in left IPL. Blood estradiol was positively correlated with white matter volume both in left parietal cortex and whole cortex. Seed-driven FC between left IPL and right secondary visual cortex was enhanced during ovulatory phase. A seed placed in right IPL revealed enhanced FC between left and right IPL during the ovulatory phase. Additionally, we found that somatosensory cortical gray matter was thinner during follicular compared to menstrual phase. We discuss these results in the context of likely evolutionary pressures selecting for enhanced perceptual sensitivity across modalities specifically during ovulation.
Collapse
Affiliation(s)
- Timothy J. Meeker
- Department of Neurosurgery, Johns Hopkins University, Baltimore, MD, United States
- Department of Neural and Pain Sciences, University of Maryland School of Dentistry, Baltimore, MD, United States
- Center to Advance Chronic Pain Research, University of Maryland Baltimore, Baltimore, MD, United States
| | - Dieuwke S. Veldhuijzen
- Institute of Psychology, Health, Medical and Neuropsychology Unit, Leiden University, Leiden, Netherlands
- Leiden Institute for Brain and Cognition, Leiden, Netherlands
| | - Michael L. Keaser
- Department of Neural and Pain Sciences, University of Maryland School of Dentistry, Baltimore, MD, United States
- Center to Advance Chronic Pain Research, University of Maryland Baltimore, Baltimore, MD, United States
| | - Rao P. Gullapalli
- Department of Diagnostic Radiology and Nuclear Imaging, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Joel D. Greenspan
- Department of Neural and Pain Sciences, University of Maryland School of Dentistry, Baltimore, MD, United States
- Center to Advance Chronic Pain Research, University of Maryland Baltimore, Baltimore, MD, United States
| |
Collapse
|
15
|
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.
Collapse
Affiliation(s)
- Alessandro Tozzi
- Department of Experimental Medicine, University of Perugia, Perugia, Italy
| | - Laura Bellingacci
- Department of Experimental Medicine, University of Perugia, Perugia, Italy
| | | |
Collapse
|
16
|
Taxier LR, Gross KS, Frick KM. Oestradiol as a neuromodulator of learning and memory. Nat Rev Neurosci 2020; 21:535-550. [PMID: 32879508 PMCID: PMC8302223 DOI: 10.1038/s41583-020-0362-7] [Citation(s) in RCA: 95] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/31/2020] [Indexed: 12/24/2022]
Abstract
Although hormones such as glucocorticoids have been broadly accepted in recent decades as general neuromodulators of memory processes, sex steroid hormones such as the potent oestrogen 17β-oestradiol have been less well recognized by the scientific community in this capacity. The predominance of females in studies of oestradiol and memory and the general (but erroneous) perception that oestrogens are 'female' hormones have probably prevented oestradiol from being more widely considered as a key memory modulator in both sexes. Indeed, although considerable evidence supports a crucial role for oestradiol in regulating learning and memory in females, a growing body of literature indicates a similar role in males. This Review discusses the mechanisms of oestradiol signalling and provides an overview of the effects of oestradiol on spatial, object recognition, social and fear memories. Although the primary focus is on data collected in females, effects of oestradiol on memory in males will be discussed, as will sex differences in the molecular mechanisms that regulate oestrogenic modulation of memory, which may have important implications for the development of future cognitive therapeutics.
Collapse
Affiliation(s)
- Lisa R Taxier
- Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
| | - Kellie S Gross
- Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
| | - Karyn M Frick
- Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, WI, USA.
| |
Collapse
|
17
|
Tao X, Yan M, Wang L, Zhou Y, Wang Z, Xia T, Liu X, Pan R, Chang Q. Effects of estrogen deprivation on memory and expression of related proteins in ovariectomized mice. ANNALS OF TRANSLATIONAL MEDICINE 2020; 8:356. [PMID: 32355800 PMCID: PMC7186664 DOI: 10.21037/atm.2020.02.57] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Background The ovariectomized (OVX) rodent model is most widely used for studying the influence of estrogen deprivation on memory. However, the results of these studies are inconsistent, in that the memory of OVX rodents shows either impairment or no change. These inconsistent outcomes increase the difficulty of researching neurochemical mechanisms and evaluating drug efficacy. One possible explanation for these discrepancies might be that the time point for memory examination after OVX varies considerably among studies. The aim of our study was to investigate the effects of estrogen deprivation on memory and the expression of memory-related proteins at different times after OVX. Methods Novel object recognition (NOR), step-through passive avoidance (STPA) and the Morris water maze (MWM) were performed to evaluate the memory performance of mice at different times after OVX. The expressions of BDNF, TrkB, ULK1 and LC3II/LC3I in the hippocampus were also assessed to explore the relevant mechanisms. Results After OVX, a significant memory impairment was found in the STPA test at 4 weeks. In the NOR and MWM tests, however, memory deficits were not observed until 8 weeks post-OVX. Interestingly, at 8 weeks, a memory rebound was found in the STPA test. In the hippocampus, the levels of BDNF and TrkB in OVX mice were markedly decreased at 4 and 8 weeks. Subsequently, a significant decrease in the ULK1 and LC3II/LC3I level in OVX mice was observed at 8 weeks. Conclusions Memory impairment in mice was observed as early as 4 weeks after OVX, although there was a possibility of memory rebound with the prolongation of estrogen deprivation. Eight weeks of estrogen deprivation would be more likely to induce hippocampus-dependent memory impairment. This progressive impairment of memory might be due to the downregulation of the BDNF/TrkB signaling pathway at the early post-OVX stage, while the decrease of autophagy level in the later stage might also contribute to these progressive alterations. The underlying relationship between the BDNF/TrkB signaling pathway and autophagy in this progressive impairment of memory requires further study.
Collapse
Affiliation(s)
- Xue Tao
- Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100193, China
| | - Mingzhu Yan
- Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100193, China
| | - Lisha Wang
- Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100193, China
| | - Yunfeng Zhou
- Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100193, China
| | - Zhi Wang
- Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100193, China
| | - Tianji Xia
- Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100193, China
| | - Xinmin Liu
- Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100193, China.,National Key Laboratory of Human Factors Engineering and the State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing 100094, China
| | - Ruile Pan
- Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100193, China
| | - Qi Chang
- Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100193, China
| |
Collapse
|
18
|
Postmenopausal hormone treatment alters neural pathways but does not improve verbal cognitive function. Menopause 2019; 25:1424-1431. [PMID: 29994967 DOI: 10.1097/gme.0000000000001157] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
OBJECTIVE Cognitive outcomes in trials of postmenopausal hormone treatment have been inconsistent. Differing outcomes may be attributed to hormone formulation, treatment duration and timing, and differential cognitive domain effects. We previously demonstrated treatment benefits on visual cognitive function. In the present study, we describe the effects of hormone treatment on verbal outcomes in the same women, seeking to understand the effects of prior versus current hormone treatment on verbal function. METHODS This is a cross-sectional evaluation of 57 women (38 hormone users [25 prior long-term users and 13 current users] and 19 never-users). Hormone users took identical formulations of estrogen or estrogen + progestin (0.625 mg/d conjugated equine estrogens with or without medroxyprogesterone acetate) for at least 10 years, beginning within 2 years of menopause. Women were evaluated with tests of verbal function and functional magnetic resonance imaging (fMRI) of a verbal discrimination task. RESULTS All women scored similarly on assessments of verbal function (Hopkins Verbal Learning Test and a verbal discrimination task performed during the fMRI scanning session); however, women ever treated with hormones had more left inferior frontal (T = 3.72; P < 0.001) and right prefrontal cortex (T = 3.53; P < 0.001) activation during the verbal task. Hormone-treated women performed slightly worse on the verbal discrimination task (mean accuracy 81.72 ± 11.57 ever-treated, 85.30 ± 5.87 never-treated, P = 0.14), took longer to respond (mean reaction time 1.10 ± 0.17 s ever-treated, 1.02 ± 0.11 never-treated, P = 0.03), and remembered fewer previously viewed words (mean accuracy 62.21 ± 8.73 ever-treated, 65.45 ± 7.49 never-treated, P = 0.18). Increased posterior cingulate activity was associated with longer response times (R = 0.323, P = 0.015) and worse delayed verbal recall (R = -0.328, P = 0.048), suggesting that increased activation was associated with less efficient cognitive processing. We did not detect between group differences in activation in the left prefrontal cortex, superior frontal cortex, thalamus, or occipital/parietal junction. CONCLUSIONS Although current and past hormone treatment was associated with differences in neural pathways used during verbal discrimination, verbal function was not higher than never-users.
Collapse
|
19
|
Baumgartner NE, Grissom EM, Pollard KJ, McQuillen SM, Daniel JM. Neuroestrogen-Dependent Transcriptional Activity in the Brains of ERE-Luciferase Reporter Mice following Short- and Long-Term Ovariectomy. eNeuro 2019; 6:ENEURO.0275-19.2019. [PMID: 31575604 PMCID: PMC6795557 DOI: 10.1523/eneuro.0275-19.2019] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 09/03/2019] [Accepted: 09/22/2019] [Indexed: 12/22/2022] Open
Abstract
Previous work has demonstrated that estrogen receptors are transcriptionally active in the absence of ovarian estrogens. The current work aims to determine whether brain-derived estrogens influence estrogen receptor-dependent transcription after short- or long-term loss of ovarian function. Experiments were conducted using estrogen response element (ERE)-Luciferase reporter mice, which express the gene for luciferase driven by consensus ERE, allowing for the quantification of ERE-dependent transcription. Brain regions examined were hippocampus, cortex, and hypothalamus. In Experiment 1, short-term (10 d) ovariectomy had no impact on ERE-dependent transcription across brain regions compared with sham surgery. In Experiment 2, chronic intracerebroventricular administration of the aromatase inhibitor letrozole significantly decreased transcriptional activity in 10-d-old ovariectomized mice across brain regions, indicating that the sustained transcription in short-term ovariectomized mice is mediated at least in part via actions of neuroestrogens. Additionally, intracerebroventricular administration of estrogen receptor antagonist ICI-182,780 blocked transcription in 10-d-old ovariectomized mice across brain regions, providing evidence that sustained transcription in ovariectomized mice is estrogen receptor dependent. In Experiment 3, long-term (70 d) ovariectomy significantly decreased ERE-dependent transcription across brain regions, though some residual activity remained. In Experiment 4, chronic intracerebroventricular letrozole administration had no impact on transcription in 70 d ovariectomized mice across brain regions, indicating that the residual ERE-dependent transcription in long-term ovariectomized mice is not mediated by neuroestrogens. Overall, the results indicate that ERE-dependent transcription in the brain continues after ovariectomy and that the actions of neuroestrogens contribute to the maintenance of ERE-dependent transcription in the brain following short-term, but not long-term, loss of ovarian function.
Collapse
Affiliation(s)
| | - Elin M Grissom
- Neuroscience Program
- Department of Psychology, Tulane University, New Orleans, Louisiana 70118
| | | | | | - Jill M Daniel
- Neuroscience Program
- Tulane Brain Institute
- Department of Psychology, Tulane University, New Orleans, Louisiana 70118
| |
Collapse
|
20
|
Hillerer KM, Slattery DA, Pletzer B. Neurobiological mechanisms underlying sex-related differences in stress-related disorders: Effects of neuroactive steroids on the hippocampus. Front Neuroendocrinol 2019; 55:100796. [PMID: 31580837 PMCID: PMC7115954 DOI: 10.1016/j.yfrne.2019.100796] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 09/26/2019] [Accepted: 09/27/2019] [Indexed: 12/19/2022]
Abstract
Men and women differ in their vulnerability to a variety of stress-related illnesses, but the underlying neurobiological mechanisms are not well understood. This is likely due to a comparative dearth of neurobiological studies that assess male and female rodents at the same time, while human neuroimaging studies often don't model sex as a variable of interest. These sex differences are often attributed to the actions of sex hormones, i.e. estrogens, progestogens and androgens. In this review, we summarize the results on sex hormone actions in the hippocampus and seek to bridge the gap between animal models and findings in humans. However, while effects of sex hormones on the hippocampus are largely consistent in animals and humans, methodological differences challenge the comparability of animal and human studies on stress effects. We summarise our current understanding of the neurobiological mechanisms that underlie sex-related differences in behavior and discuss implications for stress-related illnesses.
Collapse
Affiliation(s)
- Katharina M Hillerer
- Department of Obstetrics and Gynaecology, Salzburger Landeskrankenhaus (SALK), Paracelsus Medical University (PMU), Clinical Research Center Salzburg (CRCS), Salzburg, Austria.
| | - David A Slattery
- Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, University Hospital, Goethe University, Frankfurt, Germany
| | - Belinda Pletzer
- Department of Psychology, University of Salzburg, Salzburg, Austria; Centre for Cognitive Neuroscience, University of Salzburg, Salzburg, Austria
| |
Collapse
|
21
|
Mitchnick KA, Mendell AL, Wideman CE, Jardine KH, Creighton SD, Muller AM, Choleris E, MacLusky NJ, Winters BD. Dissociable involvement of estrogen receptors in perirhinal cortex-mediated object-place memory in male rats. Psychoneuroendocrinology 2019; 107:98-108. [PMID: 31125759 DOI: 10.1016/j.psyneuen.2019.05.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 03/21/2019] [Accepted: 05/09/2019] [Indexed: 12/11/2022]
Abstract
Estrogens and the estrogen receptors (ER) - ERα, ERβ, and the G-protein coupled estrogen receptor (GPER) - are implicated in various forms of hippocampus (HPC)-dependent memory. However, the involvement of ER-related mechanisms in perirhinal cortex (PRh), which is necessary for object memory, remains much less clear. Moreover, there is a paucity of data assessing ER contributions to cognition in males,despite documented sex differences at the cellular level.We hypothesized that estrogens in PRh are important for object memory in males, assessingthe role of 17-βestradiol (E2), ERα, ERβ, GPER, and their downstream signaling pathways, in PRh-mediated object-in-place (OiP) memory in gonadally-intact male rats. Intra-PRh administration of E2 enhanced both long-term memory (LTM; 24 h) and short-term memory (STM; 20 min). Conversely, aromatase inhibition with letrozole impaired LTM and STM. The semi-selective ER inhibitor ICI 182780 impaired LTM, but not STM. This effect may be due to inhibition of ERβ, as the ERβagonist DPN, but not ERαagonist PPT, enhanced LTM. GPER was also found to be necessary in PRh, as the antagonist G15 impaired both LTM and STM. Western blot analyses demonstrated that phosphorylation levels of the extracellular signal-related kinase (ERK2 isoform), awell-establisheddownstream signaling pathway activated by estrogens through ERα/ERβ, was elevated in PRh 5 min following OiP learning.We also reportincreased levels of c-Jun N-terminal kinase (JNK; p46 and p54 isoforms) phosphorylation in PRh 5 min following learning,consistent with recent research linking GPER activation and JNK signaling in the HPC. This effect was abolished by intra-PRh administration of G15, but not letrozole, suggesting that JNK signaling is triggered via GPER activation during OiP learning, and is possibly E2-independent, similar to findings in the HPC. These results, therefore, reveal interesting dissociations between the roles of various ERs, possibly involving both estrogen-dependent and independent mechanisms, in PRh-mediated object-place learning in male rats.
Collapse
Affiliation(s)
- Krista A Mitchnick
- Department of Psychology, University of Guelph, Canada; Collaborative Neuroscience Program, University of Guelph, Canada.
| | - Ari L Mendell
- Collaborative Neuroscience Program, University of Guelph, Canada; Department of Biomedical Sciences, University of Guelph, Canada
| | - Cassidy E Wideman
- Department of Psychology, University of Guelph, Canada; Collaborative Neuroscience Program, University of Guelph, Canada
| | - Kristen H Jardine
- Department of Psychology, University of Guelph, Canada; Collaborative Neuroscience Program, University of Guelph, Canada
| | - Samantha D Creighton
- Department of Psychology, University of Guelph, Canada; Collaborative Neuroscience Program, University of Guelph, Canada
| | | | - Elena Choleris
- Department of Psychology, University of Guelph, Canada; Collaborative Neuroscience Program, University of Guelph, Canada
| | - Neil J MacLusky
- Collaborative Neuroscience Program, University of Guelph, Canada; Department of Biomedical Sciences, University of Guelph, Canada
| | - Boyer D Winters
- Department of Psychology, University of Guelph, Canada; Collaborative Neuroscience Program, University of Guelph, Canada.
| |
Collapse
|
22
|
Tsyglakova M, McDaniel D, Hodes GE. Immune mechanisms of stress susceptibility and resilience: Lessons from animal models. Front Neuroendocrinol 2019; 54:100771. [PMID: 31325456 DOI: 10.1016/j.yfrne.2019.100771] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 06/17/2019] [Accepted: 07/09/2019] [Indexed: 12/12/2022]
Abstract
Stress has an impact on the brain and the body. A growing literature demonstrates that feedback between the peripheral immune system and the brain contributes to individual differences in the behavioral response to stress. Here we examine preclinical literature to demonstrate a holistic vision of risk and resilience to stress. We identify a variety of cellular, cytokine and molecular mechanisms in adult animals that act in concert to produce a stress susceptible individual response. We discuss how cross talk between immune cells in the brain and in the periphery act together to increase permeability across the blood brain barrier or block it, resulting in susceptible or stress resilient phenotype. These preclinical studies have importance for understanding how individual differences in the immune response to stress may be contributing to mood related disorders such as depression, anxiety and posttraumatic stress disorders.
Collapse
Affiliation(s)
- Mariya Tsyglakova
- School of Neuroscience, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA; Graduate Program in Translational Biology, Medicine and Health, Virginia Tech, Blacksburg, VA, USA
| | - Dylan McDaniel
- School of Neuroscience, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| | - Georgia E Hodes
- School of Neuroscience, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA.
| |
Collapse
|
23
|
Pollard KJ, Daniel JM. Nuclear estrogen receptor activation by insulin-like growth factor-1 in Neuro-2A neuroblastoma cells requires endogenous estrogen synthesis and is mediated by mutually repressive MAPK and PI3K cascades. Mol Cell Endocrinol 2019; 490:68-79. [PMID: 30986444 PMCID: PMC6520186 DOI: 10.1016/j.mce.2019.04.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 04/10/2019] [Accepted: 04/10/2019] [Indexed: 02/01/2023]
Abstract
Non-canonical mechanisms of estrogen receptor activation may continue to support women's cognitive health long after cessation of ovarian function. These mechanisms of estrogen receptor activation may include ligand-dependent actions via locally synthesized neuroestrogens and ligand-independent actions via growth factor-dependent activation of intracellular kinase cascades. We tested the hypothesis that ligand-dependent and ligand-independent mechanisms interact to activate nuclear estrogen receptors in the Neuro-2A neuroblastoma cell line in the absence of exogenous estrogens. Transcriptional output of estrogen receptors was measured following treatment with insulin-like growth factor-1 (IGF-1) in the presence of specific inhibitors for mitogen-activated protein kinase (MAPK), phosphoinositde-3 kinase (PI3K), and neuroestrogen synthesis. Results indicate that IGF-1-dependent activation of nuclear estrogen receptors is mediated by MAPK, is opposed PI3K, and requires concomitant endogenous neuroestrogen synthesis. We conclude that both cellular signaling context and endogenous ligand availability are important modulators of ligand-independent nuclear estrogen receptor activation.
Collapse
Affiliation(s)
- Kevin J Pollard
- Tulane Brain Institute, Tulane University, 200 Flower Hall, New Orleans, LA, 70118, USA; Neuroscience Program, Tulane University, 200 Flower Hall, New Orleans, LA, 70118, USA.
| | - Jill M Daniel
- Tulane Brain Institute, Tulane University, 200 Flower Hall, New Orleans, LA, 70118, USA; Neuroscience Program, Tulane University, 200 Flower Hall, New Orleans, LA, 70118, USA; Department of Psychology, Tulane University, 2007 Percival Stern Hall, New Orleans, LA, 70118, USA
| |
Collapse
|
24
|
Liu M, Xing F, Bian C, Zhao Y, Zhao J, Liu Y, Zhang J. Letrozole induces worse hippocampal synaptic and dendritic changes and spatial memory impairment than ovariectomy in adult female mice. Neurosci Lett 2019; 706:61-67. [PMID: 31077740 DOI: 10.1016/j.neulet.2019.05.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2018] [Revised: 04/28/2019] [Accepted: 05/07/2019] [Indexed: 01/11/2023]
Abstract
Estrogens (E2) derived from ovaries and/or local de novo synthesis in the hippocampus profoundly regulate hippocampal structure and function, but the importance of local E2 versus ovarian E2 on hippocampal synaptic plasticity and spatial memory has not been well elucidated. The present study used ovariectomy (OVX) and intraperitoneal injection of an E2 synthase inhibitor, letrozole (LET), in adult female mice to investigate changes in hippocampal steroid receptor coactivator-1 (SRC-1), postsynaptic proteins, and actin polymerization dynamics with these treatments. Changes in the CA1 spine density, synapse density and spatial learning and memory after OVX and LET were also investigated. As a result, OVX and LET showed similar regulation of the expression of GluR1, spinophilin and p-Cofilin, but LET tended to induce more significant changes in SRC-1, PSD95, Rictor, Cofilin and actin depolymerization. More significant decreases in F-actin/G-actin, CA1 spine density and synapse density were also observed after LET than after OVX. Notably, LET-treated mice showed worse learning and memory impairment than OVX mice. Taken together, these results demonstrated that circulating E2 played a limited role and that hippocampus-derived E2 played a more important role in the regulation of hippocampal synaptic plasticity and hippocampus-based spatial learning and memory.
Collapse
Affiliation(s)
- Mengying Liu
- Department of Neurobiology, Chongqing Key Laboratory of Neurobiology, Third Military Medical University, Chongqing, 400038, China
| | - Fangzhou Xing
- School of Life Sciences, Southwest University, Chongqing, 400715, China
| | - Chen Bian
- Department of Military Psychology, College of Psychology, Third Military Medical University, Chongqing, 400038, China
| | - Yangang Zhao
- Department of Neurobiology, Chongqing Key Laboratory of Neurobiology, Third Military Medical University, Chongqing, 400038, China
| | - Jikai Zhao
- Department of Neurobiology, Chongqing Key Laboratory of Neurobiology, Third Military Medical University, Chongqing, 400038, China
| | - Yan Liu
- School of Life Sciences, Southwest University, Chongqing, 400715, China.
| | - Jiqiang Zhang
- Department of Neurobiology, Chongqing Key Laboratory of Neurobiology, Third Military Medical University, Chongqing, 400038, China.
| |
Collapse
|
25
|
Koss WA, Frick KM. Activation of androgen receptors protects intact male mice from memory impairments caused by aromatase inhibition. Horm Behav 2019; 111:96-104. [PMID: 30653980 PMCID: PMC6527464 DOI: 10.1016/j.yhbeh.2019.01.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 12/21/2018] [Accepted: 01/10/2019] [Indexed: 12/17/2022]
Abstract
Although 17β-estradiol (E2) is known to regulate hippocampal function, the specific contributions of hippocampally-synthesized E2 remain unclear. Infusion of the aromatase inhibitor letrozole into the dorsal hippocampus (DH) of ovariectomized mice disrupts object recognition and object placement memory consolidation, suggesting that DH-synthesized E2 is essential for memory. However, the role of DH-synthesized E2 in memory among male rodents is unknown. Here, we examined effects of aromatase inhibition on memory consolidation in male mice. Intact and gonadectomized mice were infused with vehicle or letrozole into the DH immediately post-training in object placement and object recognition tasks. Letrozole blocked memory in both tasks among gonadectomized males only, suggesting that circulating androgens, or a rise in hippocampal androgens due to aromatase inhibition, may support memory consolidation in intact males. To test this hypothesis, intact males were infused with the androgen receptor antagonist flutamide into the DH after object training. A dose-dependent impairment was observed in both tasks, indicating that blocking androgen signaling can impair memory consolidation. To test if hippocampal androgen receptor activation protected intact males from the impairing effects of letrozole, a non-impairing dose of flutamide was co-infused with letrozole. Co-administration of both drugs blocked object placement and object recognition memory consolidation, demonstrating that letrozole impairs memory in intact males only if androgen receptors are blocked. Together, these data suggest that DH-synthesized E2 and androgen receptor activation may work in concert to mediate memory consolidation in intact males, such that androgen receptor activation protects against memory impairments caused by aromatase inhibition.
Collapse
Affiliation(s)
- Wendy A Koss
- Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, United States of America.
| | - Karyn M Frick
- Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, United States of America.
| |
Collapse
|
26
|
Neuron-Derived Estrogen Regulates Synaptic Plasticity and Memory. J Neurosci 2019; 39:2792-2809. [PMID: 30728170 PMCID: PMC6462452 DOI: 10.1523/jneurosci.1970-18.2019] [Citation(s) in RCA: 132] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 12/28/2018] [Accepted: 01/18/2019] [Indexed: 01/27/2023] Open
Abstract
17β-estradiol (E2) is produced from androgens via the action of the enzyme aromatase. E2 is known to be made in neurons in the brain, but its precise functions in the brain are unclear. Here, we used a forebrain-neuron-specific aromatase knock-out (FBN-ARO-KO) mouse model to deplete neuron-derived E2 in the forebrain of mice and thereby elucidate its functions. FBN-ARO-KO mice showed a 70–80% decrease in aromatase and forebrain E2 levels compared with FLOX controls. Male and female FBN-ARO-KO mice exhibited significant deficits in forebrain spine and synaptic density, as well as hippocampal-dependent spatial reference memory, recognition memory, and contextual fear memory, but had normal locomotor function and anxiety levels. Reinstating forebrain E2 levels via exogenous in vivo E2 administration was able to rescue both the molecular and behavioral defects in FBN-ARO-KO mice. Furthermore, in vitro studies using FBN-ARO-KO hippocampal slices revealed that, whereas induction of long-term potentiation (LTP) was normal, the amplitude was significantly decreased. Intriguingly, the LTP defect could be fully rescued by acute E2 treatment in vitro. Mechanistic studies revealed that FBN-ARO-KO mice had compromised rapid kinase (AKT, ERK) and CREB-BDNF signaling in the hippocampus and cerebral cortex. In addition, acute E2 rescue of LTP in hippocampal FBN-ARO-KO slices could be blocked by administration of a MEK/ERK inhibitor, further suggesting a key role for rapid ERK signaling in neuronal E2 effects. In conclusion, the findings provide evidence of a critical role for neuron-derived E2 in regulating synaptic plasticity and cognitive function in the male and female brain. SIGNIFICANCE STATEMENT The steroid hormone 17β-estradiol (E2) is well known to be produced in the ovaries in females. Intriguingly, forebrain neurons also express aromatase, the E2 biosynthetic enzyme, but the precise functions of neuron-derived E2 is unclear. Using a novel forebrain-neuron-specific aromatase knock-out mouse model to deplete neuron-derived E2, the current study provides direct genetic evidence of a critical role for neuron-derived E2 in the regulation of rapid AKT-ERK and CREB-BDNF signaling in the mouse forebrain and demonstrates that neuron-derived E2 is essential for normal expression of LTP, synaptic plasticity, and cognitive function in both the male and female brain. These findings suggest that neuron-derived E2 functions as a novel neuromodulator in the forebrain to control synaptic plasticity and cognitive function.
Collapse
|
27
|
Burke SN, Foster TC. Animal models of cognitive aging and circuit-specific vulnerability. HANDBOOK OF CLINICAL NEUROLOGY 2019; 167:19-36. [PMID: 31753133 DOI: 10.1016/b978-0-12-804766-8.00002-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Medial temporal lobe and prefrontal cortical structures are particularly vulnerable to dysfunction in advanced age and neurodegenerative diseases. This review focuses on cognitive aging studies in animals to illustrate the important aspects of the animal model paradigm for investigation of age-related memory and executive function loss. Particular attention is paid to the discussion of the face, construct, and predictive validity of animal models for determining the possible mechanisms of regional vulnerability in aging and for identifying novel therapeutic strategies. Aging is associated with a host of regionally specific neurobiologic alterations. Thus, targeted interventions that restore normal activity in one brain region may exacerbate aberrant activity in another, hindering the restoration of function at the behavioral level. As such, interventions that target the optimization of "cognitive networks" rather than discrete brain regions may be more effective for improving functional outcomes in the elderly.
Collapse
Affiliation(s)
- Sara N Burke
- Department of Neuroscience, William L. and Evelyn F. McKnight Brain Institute, University of Florida, Gainesville, FL, United States
| | - Thomas C Foster
- Department of Neuroscience, William L. and Evelyn F. McKnight Brain Institute, University of Florida, Gainesville, FL, United States.
| |
Collapse
|
28
|
Adverse Effects of Aromatase Inhibition on the Brain and Behavior in a Nonhuman Primate. J Neurosci 2018; 39:918-928. [PMID: 30587540 PMCID: PMC6382974 DOI: 10.1523/jneurosci.0353-18.2018] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 11/12/2018] [Accepted: 11/17/2018] [Indexed: 01/12/2023] Open
Abstract
Breast cancer patients using aromatase inhibitors (AIs) as an adjuvant therapy often report side effects, including hot flashes, mood changes, and cognitive impairment. Despite long-term use in humans, little is known about the effects of continuous AI administration on the brain and cognition. We used a primate model of human cognitive aging, the common marmoset, to examine the effects of a 4-week daily administration of the AI letrozole (20 μg, p.o.) on cognition, anxiety, thermoregulation, brain estrogen content, and hippocampal pyramidal cell physiology. Letrozole treatment was administered to both male and female marmosets and reduced peripheral levels of estradiol (E2), but unexpectedly increased E2 levels in the hippocampus. Spatial working memory and intrinsic excitability of hippocampal neurons were negatively affected by the treatment possibly due to increased hippocampal E2. While no changes in hypothalamic E2 were observed, thermoregulation was disrupted by letrozole in females only, indicating some impact on hypothalamic activity. These findings suggest adverse effects of AIs on the primate brain and call for new therapies that effectively prevent breast cancer recurrence while minimizing side effects that further compromise quality of life.SIGNIFICANCE STATEMENT Aromatase inhibitors (AIs) are used as an adjuvant therapy for estrogen-receptor-positive breast cancer and are associated with side effects, including hot flashes, depression/anxiety, and memory deficits severe enough for many women to discontinue this life-saving treatment. AIs are also used by men, yet sex differences in the reported side effects have not been systematically studied. We show that AI-treated male and female marmosets exhibit behavioral changes consistent with these CNS symptoms, as well as elevated hippocampal estradiol and compromised hippocampal physiology. These findings illustrate the need for (1) a greater understanding of the precise mechanisms by which AIs impact brain function and (2) the development of new treatment approaches for breast cancer patients that minimize adverse effects on the brain.
Collapse
|
29
|
Latent Sex Differences in Molecular Signaling That Underlies Excitatory Synaptic Potentiation in the Hippocampus. J Neurosci 2018; 39:1552-1565. [PMID: 30578341 DOI: 10.1523/jneurosci.1897-18.2018] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 11/27/2018] [Accepted: 12/13/2018] [Indexed: 01/25/2023] Open
Abstract
Excitatory synapses can be potentiated by chemical neuromodulators, including 17β-estradiol (E2), or patterns of synaptic activation, as in long-term potentiation (LTP). Here, we investigated kinases and calcium sources required for acute E2-induced synaptic potentiation in the hippocampus of each sex and tested whether sex differences in kinase signaling extend to LTP. We recorded EPSCs from CA1 pyramidal cells in hippocampal slices from adult rats and used specific inhibitors of kinases and calcium sources. This revealed that, although E2 potentiates synapses to the same degree in each sex, cAMP-activated protein kinase (PKA) is required to initiate potentiation only in females. In contrast, mitogen-activated protein kinase, Src tyrosine kinase, and rho-associated kinase are required for initiation in both sexes; similarly, Ca2+/calmodulin-activated kinase II is required for expression/maintenance of E2-induced potentiation in both sexes. Calcium source experiments showed that L-type calcium channels and calcium release from internal stores are both required for E2-induced potentiation in females, whereas in males, either L-type calcium channel activation or calcium release from stores is sufficient to permit potentiation. To investigate the generalizability of a sex difference in the requirement for PKA in synaptic potentiation, we tested how PKA inhibition affects LTP. This showed that, although the magnitude of both high-frequency stimulation-induced and pairing-induced LTP is the same between sexes, PKA is required for LTP in females but not males. These results demonstrate latent sex differences in mechanisms of synaptic potentiation in which distinct molecular signaling converges to common functional endpoints in males and females.SIGNIFICANCE STATEMENT Chemical- and activity-dependent neuromodulation alters synaptic strength in both male and female brains, yet few studies have compared mechanisms of neuromodulation between the sexes. Here, we studied molecular signaling that underlies estrogen-induced and activity-dependent potentiation of excitatory synapses in the hippocampus. We found that, despite similar magnitude increases in synaptic strength in males and females, the roles of cAMP-regulated protein kinase, internal calcium stores, and L-type calcium channels differ between the sexes. Therefore, latent sex differences in which the same outcome is achieved through distinct underlying mechanisms in males and females include kinase and calcium signaling involved in synaptic potentiation, demonstrating that sex is an important factor in identification of molecular targets for therapeutic development based on mechanisms of neuromodulation.
Collapse
|
30
|
Seitz J, Kubicki M, Jacobs EG, Cherkerzian S, Weiss BK, Papadimitriou G, Mouradian P, Buka S, Goldstein JM, Makris N. Impact of sex and reproductive status on memory circuitry structure and function in early midlife using structural covariance analysis. Hum Brain Mapp 2018; 40:1221-1233. [PMID: 30548738 DOI: 10.1002/hbm.24441] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Revised: 10/11/2018] [Accepted: 10/13/2018] [Indexed: 01/13/2023] Open
Abstract
Research on age-related memory alterations traditionally targets individuals aged ≥65 years. However, recent studies emphasize the importance of early aging processes. We therefore aimed to characterize variation in brain gray matter structure in early midlife as a function of sex and menopausal status. Subjects included 94 women (33 premenopausal, 29 perimenopausal, and 32 postmenopausal) and 99 demographically comparable men from the New England Family Study. Subjects were scanned with a high-resolution T1 sequence on a 3 T whole body scanner. Sex and reproductive-dependent structural differences were evaluated using Box's M test and analysis of covariances (ANCOVAs) for gray matter volumes. Brain regions of interest included dorsolateral prefrontal cortex (DLPFC), inferior parietal lobule (iPAR), anterior cingulate cortex (ACC), hippocampus (HIPP), and parahippocampus. While we observed expected significant sex differences in volume of hippocampus with women of all groups having higher volumes than men relative to cerebrum size, we also found significant differences in the covariance matrices of perimenopausal women compared with postmenopausal women. Associations between ACC and HIPP/iPAR/DLPFC were higher in postmenopausal women and correlated with better memory performance. Findings in this study underscore the importance of sex and reproductive status in early midlife for understanding memory function with aging.
Collapse
Affiliation(s)
- Johanna Seitz
- Psychiatry Neuroimaging Laboratory, Department of Psychiatry, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Marek Kubicki
- Psychiatry Neuroimaging Laboratory, Department of Psychiatry, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts.,Departments of Psychiatry, Neurology and Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Center for Morphometric Analysis, Center for Neural Systems Investigations, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts.,Department of Psychiatry, Obstetrics and Gynecology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts
| | - Emily G Jacobs
- Department of Medicine, Harvard Medical School, Boston, Massachusetts.,Division of Women's Health, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Sara Cherkerzian
- Department of Psychiatry, Obstetrics and Gynecology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts.,Department of Medicine, Harvard Medical School, Boston, Massachusetts.,Division of Women's Health, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Blair K Weiss
- Department of Medicine, Harvard Medical School, Boston, Massachusetts.,Division of Women's Health, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - George Papadimitriou
- Departments of Psychiatry, Neurology and Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Center for Morphometric Analysis, Center for Neural Systems Investigations, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts
| | - Palig Mouradian
- Departments of Psychiatry, Neurology and Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Center for Morphometric Analysis, Center for Neural Systems Investigations, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts
| | - Stephen Buka
- Department of Community Health, Brown University, Providence, Rhode Island
| | - Jill M Goldstein
- Departments of Psychiatry, Neurology and Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Center for Morphometric Analysis, Center for Neural Systems Investigations, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts.,Department of Psychiatry, Obstetrics and Gynecology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts.,Department of Medicine, Harvard Medical School, Boston, Massachusetts.,Division of Women's Health, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Nikos Makris
- Psychiatry Neuroimaging Laboratory, Department of Psychiatry, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts.,Departments of Psychiatry, Neurology and Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Center for Morphometric Analysis, Center for Neural Systems Investigations, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts
| |
Collapse
|
31
|
Effects of the experimental administration of oral estrogen on prefrontal functions in healthy young women. Psychopharmacology (Berl) 2018; 235:3465-3477. [PMID: 30306229 DOI: 10.1007/s00213-018-5061-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 10/02/2018] [Indexed: 01/01/2023]
Abstract
17-Beta-estradiol (E2) stimulates neural plasticity and dopaminergic transmission in the prefrontal cortex, which is critically involved in attentional control, working memory, and other executive functions. Studies investigating E2's actions on prefrontally mediated behavior in the course of the menstrual cycle or during hormone replacement therapy are inconclusive, with numerous null findings as well as beneficial and detrimental effects. The current study focused on the effect of E2 on attentional performance, as animal studies indicate that supraphysiological doses (i.e., above estrous cycle levels) of E2 have beneficial effects on measures of attention in female rodents. To translate these findings to humans, we administered 12 mg E2-valerate or placebo orally to 34 naturally cycling women in the low-hormone early follicular phase using a randomized, double-blinded, pre-post design. Behavioral performance was tested twice during baseline and E2 peak, where E2 levels reached mildly supraphysiological levels in the E2 group. Aside from mainly prefrontally mediated tasks of attention, working memory, and other executive functions, we employed tasks of affectively modulated attention, emotion recognition, and verbal memory. E2 administration had a significant, but subtle negative impact on general processing speed and working memory performance. These effects could be related to an overstimulation of dopaminergic transmission. The negative effect of supraphysiological E2 on working memory connects well to animal literature. There were no effects on attentional performance or any other measure. This could be explained by different E2 levels being optimal for changing behavioral performance in specific tasks, which likely depends on the brain regions involved.
Collapse
|
32
|
Van Dyk K, Crespi CM, Bower JE, Castellon SA, Petersen L, Ganz PA. The cognitive effects of endocrine therapy in survivors of breast cancer: A prospective longitudinal study up to 6 years after treatment. Cancer 2018; 125:681-689. [PMID: 30485399 DOI: 10.1002/cncr.31858] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 09/10/2018] [Accepted: 10/22/2018] [Indexed: 12/30/2022]
Abstract
BACKGROUND After treatment of primary breast cancer, endocrine therapy (ET) is prescribed for patients with hormone receptor-positive cancers. Despite ET recommendations of 5 to 10 years of treatment, to the authors' knowledge there is little prospective study of its impact on cognitive function over an extended period of time. ET has known pharmacologic effects on the brain. Cognitive side effects are a concern for many women, with mixed findings reported in various studies. The current prospective longitudinal study examined the neuropsychological effects of ET over time, up to 6 years after treatment. METHODS A total of 189 survivors of early-stage breast cancer enrolled in the study prior to initiating ET if prescribed, and were followed at 6 months (175 patients), 12 months (173 patients), and for 3 to 6 years (102 patients) with self-report and neuropsychological assessments. Using linear mixed models, the authors examined whether neuropsychological performance or impairment rates differed over time based on whether or not ET was received. RESULTS The authors did not find any effect of ET on neuropsychological performance or impairment at any time point among survivors who received it compared with women who did not. However, those who participated in the 3-year to 6-year year visit demonstrated better executive function at baseline. CONCLUSIONS In the current observational cohort study, no detrimental effect of ET on cognitive function was identified in survivors of early-stage breast cancer receiving treatment with ET compared with those who were not.
Collapse
Affiliation(s)
- Kathleen Van Dyk
- Department of Psychiatry and Biobehavioral Sciences, Semel Institute for Neuroscience and Human Behavior, University of California at Los Angeles, Los Angeles, California.,Jonsson Comprehensive Cancer Center, University of California at Los Angeles, Los Angeles, California
| | - Catherine M Crespi
- Department of Psychiatry and Biobehavioral Sciences, Semel Institute for Neuroscience and Human Behavior, University of California at Los Angeles, Los Angeles, California.,Jonsson Comprehensive Cancer Center, University of California at Los Angeles, Los Angeles, California.,Department of Biostatistics, Fielding School of Public Health, University of California at Los Angeles, Los Angeles, California
| | - Julienne E Bower
- Department of Psychiatry and Biobehavioral Sciences, Semel Institute for Neuroscience and Human Behavior, University of California at Los Angeles, Los Angeles, California.,Jonsson Comprehensive Cancer Center, University of California at Los Angeles, Los Angeles, California.,Department of Psychology, University of California at Los Angeles, Los Angeles, California
| | - Steven A Castellon
- Department of Psychiatry and Biobehavioral Sciences, Semel Institute for Neuroscience and Human Behavior, University of California at Los Angeles, Los Angeles, California.,VA Greater Los Angeles Healthcare System, Los Angeles, California
| | - Laura Petersen
- Jonsson Comprehensive Cancer Center, University of California at Los Angeles, Los Angeles, California
| | - Patricia A Ganz
- Jonsson Comprehensive Cancer Center, University of California at Los Angeles, Los Angeles, California.,David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California.,Department of Health Policy and Management, Fielding School of Public Health, University of California at Los Angeles, Los Angeles, California
| |
Collapse
|
33
|
Women with high estradiol status are protected against declarative memory impairment by pre-learning stress. Neurobiol Learn Mem 2018; 155:403-411. [PMID: 30172954 DOI: 10.1016/j.nlm.2018.08.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 07/26/2018] [Accepted: 08/29/2018] [Indexed: 11/21/2022]
Abstract
Stress is a potent modulator of learning and memory. Factors contributing to whether stress aids or impairs memory are timing of the stressor, memory stage, form of memory studied, and sex of the subjects. The female sex hormone 17-beta-estradiol (E2) has widespread effects in the brain and affects hippocampus-dependent memory in animals. In humans, the interaction between stress effects and E2 has not been widely studied. We report data from a healthy sample divided into 3 hormone-status groups: free-cycling women in the early follicular phase (EF: low E2, low progesterone [P4]), or during midcycle (MC: high E2, low P4), and men. Participants within each hormone-status group were randomly assigned to a psychosocial stressor or a control treatment 37 min before encoding a short story of neutral content. We found a Hormone status × Stress × Time (immediate, 35-min, 24-h delayed recall) interaction. Irrespective of time, hormone status mattered only after stress treatment: stressed early follicular women had poorer recall compared to stressed men and midcycle women. Only in the early follicular group, recall was negatively correlated with increases in salivary cortisol, but not with blood levels of E2 and P4. To uncover changes beyond immediate recall, we computed the individual percent change relative to immediate recall and repeated the analysis for these adjusted 35-min and 24-h data. Despite the lack of a stress effect in raw data, memory in stressed men was more stable over time (35-min and 24-h delay) than in unstressed men. In contrast, stressed EF-women (vs. control) recalled less at the 35-min and (as a trend) at the 24-h delay. Stressed MC-women (vs. control) showed less recall only at the 35-min delay while compensating this stress effect after a 24-h consolidation interval. Overall, results suggest that women in high-E2 midcycle phase could be less vulnerable to effects of pre-learning stress on declarative memory encoding and consolidation.
Collapse
|
34
|
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.
Collapse
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
| |
Collapse
|
35
|
Pollard KJ, Wartman HD, Daniel JM. Previous estradiol treatment in ovariectomized mice provides lasting enhancement of memory and brain estrogen receptor activity. Horm Behav 2018; 102:76-84. [PMID: 29742445 PMCID: PMC6004337 DOI: 10.1016/j.yhbeh.2018.05.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 04/18/2018] [Accepted: 05/03/2018] [Indexed: 12/17/2022]
Affiliation(s)
| | | | - Jill M Daniel
- Tulane University, Tulane Brain Institute, United States; Tulane University, Department of Psychology, United States
| |
Collapse
|
36
|
Zhao J, Bian C, Liu M, Zhao Y, Sun T, Xing F, Zhang J. Orchiectomy and letrozole differentially regulate synaptic plasticity and spatial memory in a manner that is mediated by SRC-1 in the hippocampus of male mice. J Steroid Biochem Mol Biol 2018; 178:354-368. [PMID: 29452160 DOI: 10.1016/j.jsbmb.2018.02.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Revised: 02/07/2018] [Accepted: 02/12/2018] [Indexed: 11/23/2022]
Abstract
Hippocampal synaptic plasticity is the basis of spatial memory and cognition and is strongly regulated by both testicular androgens (testosterone, T) and hippocampal estrogens (17β-estradiol, E2) converted from T by aromatase, which is inhibited by letrozole (LET), but the contribution of each pathway to spatial memory and the associated mechanisms are unclear. In this study, we first used orchiectomy (ORX) and LET injection to investigate the effects of T and hippocampal E2 on spatial memory and hippocampal synaptic plasticity. Next, we examined the changes in steroid receptors and steroid receptor coactivator-1 (SRC-1) under these treatments. Finally, we constructed an SRC-1 RNA interference lentivirus and an AROM overexpression lentivirus to explore the roles of SRC-1 under T replacement and AROM overexpression. The results revealed spatial memory impairment only after LET. LET induced more actin depolymerization and greater losses of spines, synapses, and postsynaptic proteins compared with ORX. Moreover, although ERα and ERβ were affected by LET and ORX at similar levels, AR, GPR30, and SRC-1 were dramatically decreased by LET compared with ORX. Finally, the T and AROM overexpression-induced changes in synaptic proteins and actin polymerization were blocked by SRC-1 inhibition. These results demonstrate that testicular androgens play a limited role, whereas local E2 is more important for cognition, which may explain why castrated men such as eunuchs usually do not have cognitive disorders. These results also suggest a pivotal role of SRC-1 in the action of steroids; thus, SRC-1 may serve as a novel therapeutic target for cognitive disorders.
Collapse
Affiliation(s)
- Jikai Zhao
- Department of Neurobiology, Chongqing Key Laboratory of Neurobiology, Third Military Medical University, Chongqing, 400038, China
| | - Chen Bian
- Department of Military Psychology, College of Psychology, Third Military Medical University, Chongqing, 400038, China
| | - Mengying Liu
- 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
| | - Tao Sun
- Department of Neurobiology, Chongqing Key Laboratory of Neurobiology, Third Military Medical University, Chongqing, 400038, China
| | - Fangzhou Xing
- Department of Neurobiology, Chongqing Key Laboratory of Neurobiology, Third Military Medical University, Chongqing, 400038, China; School of Life Sciences, Southwest University, Chongqing, 400715, China
| | - Jiqiang Zhang
- Department of Neurobiology, Chongqing Key Laboratory of Neurobiology, Third Military Medical University, Chongqing, 400038, China.
| |
Collapse
|
37
|
Linear and inverted U-shaped dose-response functions describe estrogen effects on hippocampal activity in young women. Nat Commun 2018; 9:1220. [PMID: 29572476 PMCID: PMC5865215 DOI: 10.1038/s41467-018-03679-x] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Accepted: 03/02/2018] [Indexed: 01/07/2023] Open
Abstract
In animals, 17-beta-estradiol (E2) enhances hippocampal plasticity in a dose-dependent, monotonically increasing manner, but this relationship can also exhibit an inverted U-shaped function. To investigate E2’s dose-response function in the human hippocampus, we pharmacologically increased E2 levels in 125 naturally cycling women (who were in their low-hormone menstruation phase) to physiological (equivalent to menstrual cycle peak) and supraphysiological (equivalent to levels during early pregnancy) concentrations in a placebo-controlled design. Twenty-four hours after first E2 intake, we measured brain activity during encoding of neutral and negative pictures and then tested recognition memory 24 h after encoding. Here we report that E2 exhibits both a monotonically increasing relationship with hippocampal activity as well as an inverted U-shaped relationship, depending on the hippocampal region. Hippocampal activity exhibiting a U-shaped relationship inflects at supraphysiological E2 levels, suggesting that while E2 within physiological ranges stimulates hippocampal activity, supraphysiological ranges show opposite effects. While estrogen is known to change hippocampal activity in animals, it is not known if this effect extends to humans. Here, authors vary the doses of estrogen in young women and show that the effects on hippocampal activity can be described by linear and inverted-U shaped dose-response functions.
Collapse
|
38
|
Blaustein JD. Treatments for Breast Cancer That Affect Cognitive Function in Postmenopausal Women. ACTA ACUST UNITED AC 2017. [DOI: 10.1177/2372732217717271] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
About one of every eight women will develop breast cancer during her lifetime. Approximately a quarter of a million new cancer cases are expected in 2017. Of those breast cancers, 60% to 75% will have characteristics suggesting that estrogens are likely to promote growth of those tumors. Consequently, inhibiting estrogen synthesis is one of the main treatments of choice. Therefore, women must understand the potential adverse effects of those treatments on quality of life. This review discusses (a) the role of estrogens locally synthesized in the brain in laboratory animals and women, (b) the effects of estrogens and blockers of estrogen synthesis on cognitive function, and (c) the limitations in experiments on women taking inhibitors. This article aims to provide women and oncologists with information that will encourage them to consider side effects of aromatase inhibitors (AIs) treatment on the brain.
Collapse
|
39
|
Diaz A, Treviño S, Vázquez-Roque R, Venegas B, Espinosa B, Flores G, Fernández-G JM, Montaño LF, Guevara J. The aminoestrogen prolame increases recognition memory and hippocampal neuronal spine density in aged mice. Synapse 2017; 71:e21987. [PMID: 28545157 DOI: 10.1002/syn.21987] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 05/18/2017] [Accepted: 05/19/2017] [Indexed: 12/24/2022]
Abstract
The aging brain shows biochemical and morphological changes in the dendrites of pyramidal neurons from the limbic system associated with memory loss. Prolame (N-(3-hydroxy-1,3,5 (10)-estratrien-17β-yl)-3-hydroxypropylamine) is a non-feminizing aminoestrogen with antithrombotic activity that prevents neuronal deterioration, oxidative stress, and neuroinflammation. Our aim was to evaluate the effect of prolame on motor and cognitive processes, as well as its influence on the dendritic morphology of neurons at the CA1, CA3, and granule cells of the dentate gyrus (DG) regions of hippocampus (HP), and medium spiny neurons of the nucleus accumbens (NAcc) of aged mice. Dendritic morphology was assessed with the Golgi-Cox stain procedure followed by Sholl analysis. Prolame (60 µg/kg) was subcutaneously injected daily for 60 days in 18-month-old mice. Immediately after treatment, locomotor activity in a new environment and recognition memory using the Novel Object Recognition Task (NORT) were evaluated. Prolame-treated mice showed a significant increase in the long-term exploration quotient, but locomotor activity was not modified in comparison to control animals. Prolame-treated mice showed a significant increase in dendritic spines density and dendritic length in neurons of the CA1, CA3, and DG regions of the HP, whereas dendrites of neurons in the NAcc remained unmodified. In conclusion, prolame administration promotes hippocampal plasticity processes but not in the NAcc neurons of aged mice, thus improving long-term recognition memory. Prolame could become a pharmacological alternative to prevent or delay the brain aging process, and thus the emergence of neurodegenerative diseases that affect memory.
Collapse
Affiliation(s)
- Alfonso Diaz
- Facultad de Ciencias Químicas, Benemérita Universidad Autónoma de Puebla, Pue, Mexico
| | - Samuel Treviño
- Facultad de Ciencias Químicas, Benemérita Universidad Autónoma de Puebla, Pue, Mexico
| | - Rubén Vázquez-Roque
- Instituto de Fisiología, Benemérita Universidad Autónoma de Puebla, Pue, Mexico
| | - Berenice Venegas
- Facultad de Ciencias Biológicas, Benemérita Universidad Autónoma de Puebla, Pue, Mexico
| | - Blanca Espinosa
- Departamento de Bioquímica, Instituto Nacional de Enfermedades Respiratorias INER, Ciudad de México, Mexico
| | - Gonzalo Flores
- Instituto de Fisiología, Benemérita Universidad Autónoma de Puebla, Pue, Mexico
| | | | - Luis F Montaño
- Departamento de Biología Celular y Tisular, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Jorge Guevara
- Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| |
Collapse
|
40
|
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.
Collapse
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.
| |
Collapse
|
41
|
Sex-Dependent Regulation of Aromatase-Mediated Synaptic Plasticity in the Basolateral Amygdala. J Neurosci 2016; 37:1532-1545. [PMID: 28028198 DOI: 10.1523/jneurosci.1532-16.2016] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 11/11/2016] [Accepted: 12/11/2016] [Indexed: 02/01/2023] Open
Abstract
The basolateral amygdala (BLA) integrates sensory input from cortical and subcortical regions, a function that requires marked synaptic plasticity. Here we provide evidence that cytochrome P450 aromatase (AROM), the enzyme converting testosterone to 17β-estradiol (E2), contributes to the regulation of this plasticity in a sex-specific manner. We show that AROM is expressed in the BLA, particularly in the basolateral nucleus (BL), in male and female rodents. Systemic administration of the AROM inhibitor letrozole reduced spine synapse density in the BL of adult female mice but not in the BL of male mice. Similarly, in organotypic corticoamygdalar slice cultures from immature rats, treatment with letrozole significantly reduced spine synapses in the BL only in cultures derived from females. In addition, letrozole sex-specifically altered synaptic properties in the BL: in acute slices from juvenile (prepubertal) female rats, wash-in of letrozole virtually abolished long-term potentiation (LTP), whereas it did not prevent the generation of LTP in the slices from males. Together, these data indicate that neuron-derived E2 modulates synaptic plasticity in rodent BLA sex-dependently. As protein expression levels of AROM, estrogen and androgen receptors did not differ between males and females and were not sex-specifically altered by letrozole, the findings suggest sex-specific mechanisms of E2 signaling.SIGNIFICANCE STATEMENT The basolateral amygdala (BLA) is a key structure of the fear circuit. This research reveals a sexually dimorphic regulation of synaptic plasticity in the BLA involving neuronal aromatase, which produces the neurosteroid 17β-estradiol (E2). As male and female neurons in rodent BLA responded differently to aromatase inhibition both in vivo and in vitro, our findings suggest that E2 signaling in BLA neurons is regulated sex-dependently, presumably via mechanisms that have been established during sexual determination. These findings could be relevant for the understanding of sex differences in mood disorders and of the side effects of cytochrome P450 aromatase inhibitors, which are frequently used for breast cancer therapy.
Collapse
|
42
|
Fester L, Zhou L, Ossig C, Labitzke J, Bläute C, Bader M, Vollmer G, Jarry H, Rune GM. Synaptopodin is regulated by aromatase activity. J Neurochem 2016; 140:126-139. [PMID: 27861893 DOI: 10.1111/jnc.13889] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Revised: 10/17/2016] [Accepted: 10/28/2016] [Indexed: 01/25/2023]
Abstract
Locally synthesized estradiol plays an important role in synaptic plasticity in the hippocampus. We have previously shown that in hippocampal neurons, activity of the enzyme aromatase, which converts testosterone into estradiol, is reduced via Ca2+ -dependent phosphorylation. Synaptopodin is a highly estrogen responsive protein, and it has been shown that it is an important regulator of synaptic plasticity, mediated by its close association with internal calcium stores. In this study, we show that the expression of synaptopodin is stronger in the hippocampus of female animals than in that of male animals. Phosphorylation of aromatase, using letrozole, however, down-regulates synaptopodin immunohistochemistry in the hippocampus of both male and females. Similarly, in aromatase knock-out mice synaptopodin expression in the hippocampus is reduced sex independently. Using primary-dissociated hippocampal neurons, we found that evoked release of Ca2+ from internal stores down-regulates aromatase activity, which is paralleled by reduced expression of synaptopodin. Opposite effects were achieved after inhibition of the release. Calcium-dependent regulation of synaptopodin expression was abolished when the control of aromatase activity by the Ca2+ transients was disrupted. Our data suggest that the regulation of aromatase activity by Ca2+ transients in neurons contributes to synaptic plasticity in the hippocampus of male and female animals as an on-site regulatory mechanism.
Collapse
Affiliation(s)
- Lars Fester
- Institute of Neuroanatomy, University Medical Center, Hamburg, Germany
| | - Lepu Zhou
- Institute of Neuroanatomy, University Medical Center, Hamburg, Germany
| | - Christiana Ossig
- Institute of Neuroanatomy, University Medical Center, Hamburg, Germany
| | - Jan Labitzke
- Institute of Neuroanatomy, University Medical Center, Hamburg, Germany
| | - Corinna Bläute
- Institute of Neuroanatomy, University Medical Center, Hamburg, Germany
| | - Manuela Bader
- Department of Biology, Technische Universität Dresden, Dresden, Germany
| | - Günter Vollmer
- Department of Biology, Technische Universität Dresden, Dresden, Germany
| | - Hubertus Jarry
- Department of Experimental Endocrinology, University of Goettingen, Goettingen, Germany
| | - Gabriele M Rune
- Institute of Neuroanatomy, University Medical Center, Hamburg, Germany
| |
Collapse
|
43
|
Koss WA, Frick KM. Sex differences in hippocampal function. J Neurosci Res 2016; 95:539-562. [DOI: 10.1002/jnr.23864] [Citation(s) in RCA: 99] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Revised: 06/28/2016] [Accepted: 07/11/2016] [Indexed: 12/25/2022]
Affiliation(s)
- Wendy A. Koss
- Department of Psychology; University of Wisconsin-Milwaukee; Milwaukee Wisconsin
| | - Karyn M. Frick
- Department of Psychology; University of Wisconsin-Milwaukee; Milwaukee Wisconsin
| |
Collapse
|
44
|
Fester L, Brandt N, Windhorst S, Pröls F, Bläute C, Rune GM. Control of aromatase in hippocampal neurons. J Steroid Biochem Mol Biol 2016; 160:9-14. [PMID: 26472556 DOI: 10.1016/j.jsbmb.2015.10.009] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Revised: 10/01/2015] [Accepted: 10/08/2015] [Indexed: 10/22/2022]
Abstract
Our knowledge on estradiol-induced modulation of synaptic function in the hippocampus is widely based on results following the application of the steroid hormone to either cell cultures, or after the treatment of gonadectomized animals, thus ignoring local neuronal estrogen synthesis. We and others, however, have shown that hippocampus-derived estradiol also controls synaptic plasticity in the hippocampus. Estradiol synthesis in the hippocampus is regulated by several mechanisms, which are reviewed in this report. The regulation of the activity of aromatase, the final enzyme of estrogen biosynthesis, by Ca(2+) transients, is of particular interest. Aromatase becomes inactivated as soon as it is phosphorylated by Ca(2+)-dependent kinases upon calcium release from internal stores. Accordingly, thapsigargin dephosphorylates aromatase and stimulates estradiol synthesis by depletion of internal Ca(2+) stores. Vice versa, letrozole, an aromatase inhibitor, phosphorylates aromatase and reduces estradiol synthesis. Treatment of the cultures with 17β-estradiol results in phosphorylation of the enzyme and increased aromatase protein expression, which suggests that estradiol synthesis in hippocampal neurons is regulated in an autocrine manner.
Collapse
Affiliation(s)
- Lars Fester
- University Medical Center Hamburg Eppendorf, Institute of Neuroanatomy, Martinistr. 52, 20246 Hamburg, Germany
| | - Nicola Brandt
- University Medical Center Hamburg Eppendorf, Institute of Neuroanatomy, Martinistr. 52, 20246 Hamburg, Germany
| | - Sabine Windhorst
- Department of Biochemistry and Signal Transduction, Martinistr. 52, 20246 Hamburg, Germany
| | - Felicitas Pröls
- University Medical Center Hamburg Eppendorf, Institute of Neuroanatomy, Martinistr. 52, 20246 Hamburg, Germany
| | - Corinna Bläute
- University Medical Center Hamburg Eppendorf, Institute of Neuroanatomy, Martinistr. 52, 20246 Hamburg, Germany
| | - Gabriele M Rune
- University Medical Center Hamburg Eppendorf, Institute of Neuroanatomy, Martinistr. 52, 20246 Hamburg, Germany.
| |
Collapse
|
45
|
Daulatzai MA. Evidence of neurodegeneration in obstructive sleep apnea: Relationship between obstructive sleep apnea and cognitive dysfunction in the elderly. J Neurosci Res 2015; 93:1778-94. [DOI: 10.1002/jnr.23634] [Citation(s) in RCA: 114] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 08/02/2015] [Accepted: 08/04/2015] [Indexed: 02/06/2023]
Affiliation(s)
- Mak Adam Daulatzai
- Sleep Disorders Group, EEE/Melbourne School of Engineering, The University of Melbourne; Parkville Victoria Australia
| |
Collapse
|
46
|
Vierk R, Bayer J, Freitag S, Muhia M, Kutsche K, Wolbers T, Kneussel M, Sommer T, Rune GM. Structure-function-behavior relationship in estrogen-induced synaptic plasticity. Horm Behav 2015; 74:139-48. [PMID: 26012713 DOI: 10.1016/j.yhbeh.2015.05.008] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Revised: 04/23/2015] [Accepted: 05/17/2015] [Indexed: 01/06/2023]
Abstract
This article is part of a Special Issue "Estradiol and Cognition". In estrogen-induced synaptic plasticity, a correlation of structure, function and behavior in the hippocampus has been widely established. 17ß-estradiol has been shown to increase dendritic spine density on hippocampal neurons and is accompanied by enhanced long-term potentiation and improved performance of animals in hippocampus-dependent memory tests. After inhibition of aromatase, the final enzyme of estradiol synthesis, with letrozole we consistently found a strong and significant impairment of long-term potentiation (LTP) in female mice as early as after six hours of treatment. LTP impairment was followed by loss of hippocampal spine synapses in the hippocampal CA1 area. Interestingly, these effects were not found in male animals. In the Morris water maze test, chronic administration of letrozole did not alter spatial learning and memory in either female or male mice. In humans, analogous effects of estradiol on hippocampal morphology and physiology were observed using neuroimaging techniques. However, similar to our findings in mice, an effect of estradiol on memory performance has not been consistently observed.
Collapse
Affiliation(s)
- R Vierk
- Institute of Neuroanatomy, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany
| | - J Bayer
- Institute for Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany
| | - S Freitag
- Department of Molecular Neurogenetics, Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf, Falkenried 94, 20151 Hamburg, Germany
| | - M Muhia
- Department of Molecular Neurogenetics, Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf, Falkenried 94, 20151 Hamburg, Germany
| | - K Kutsche
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany
| | - T Wolbers
- Center for Behavioral Brain Sciences, Leipziger Str. 44, 39120 Magdeburg, Germany
| | - M Kneussel
- Department of Molecular Neurogenetics, Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf, Falkenried 94, 20151 Hamburg, Germany
| | - T Sommer
- Institute for Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany.
| | - G M Rune
- Institute of Neuroanatomy, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany.
| |
Collapse
|