1
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Puri TA, Lieblich SE, Ibrahim M, Galea LAM. Pregnancy history and estradiol influence spatial memory, hippocampal plasticity, and inflammation in middle-aged rats. Horm Behav 2024; 165:105616. [PMID: 39168073 DOI: 10.1016/j.yhbeh.2024.105616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2024] [Revised: 07/28/2024] [Accepted: 08/07/2024] [Indexed: 08/23/2024]
Abstract
Pregnancy and motherhood can have long-term effects on cognition and brain aging in both humans and rodents. Estrogens are related to cognitive function and neuroplasticity. Estrogens can improve cognition in postmenopausal women, but the evidence is mixed, partly due to differences in age of initiation, type of menopause, dose, formulation and route of administration. Additionally, past pregnancy influences brain aging and cognition as a younger age of first pregnancy in humans is associated with poorer aging outcomes. However, few animal studies have examined specific features of pregnancy history or the possible mechanisms underlying these changes. We examined whether maternal age at first pregnancy and estradiol differentially affected hippocampal neuroplasticity, inflammation, spatial reference cognition, and immediate early gene activation in response to spatial memory retrieval in middle-age. Thirteen-month-old rats (who were nulliparous (never mothered) or previously primiparous (had a litter) at three or seven months) received daily injections of estradiol (or vehicle) for sixteen days and were tested on the Morris Water Maze. An older age of first pregnancy was associated with impaired spatial memory but improved performance on reversal training, and increased number of new neurons in the ventral hippocampus. Estradiol decreased activation of new neurons in the dorsal hippocampus, regardless of parity history. Estradiol also decreased the production of anti-inflammatory cytokines based on age of first pregnancy. This work suggests that estradiol affects neuroplasticity and neuroinflammation in middle age, and that age of first pregnancy can have long lasting effects on hippocampus structure and function.
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Affiliation(s)
- Tanvi A Puri
- Graduate Program in Neuroscience, University of British Columbia, Vancouver, BC, Canada; Djavad Mowafaghian Center for Brain Health, University of British Columbia, Vancouver, BC, Canada
| | - Stephanie E Lieblich
- Djavad Mowafaghian Center for Brain Health, University of British Columbia, Vancouver, BC, Canada
| | - Muna Ibrahim
- Djavad Mowafaghian Center for Brain Health, University of British Columbia, Vancouver, BC, Canada
| | - Liisa A M Galea
- Djavad Mowafaghian Center for Brain Health, University of British Columbia, Vancouver, BC, Canada; Center for Addiction and Mental Health, Toronto, ON, Canada; Department of Psychiatry, University of Toronto, Toronto, ON, Canada.
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2
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Breeze B, Connell E, Wileman T, Muller M, Vauzour D, Pontifex MG. Menopause and Alzheimer's disease susceptibility: Exploring the potential mechanisms. Brain Res 2024; 1844:149170. [PMID: 39163895 DOI: 10.1016/j.brainres.2024.149170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2024] [Revised: 08/15/2024] [Accepted: 08/17/2024] [Indexed: 08/22/2024]
Abstract
Alzheimer's Disease (AD), responsible for 62% of all dementia cases, is a progressive neurodegenerative condition that leads to cognitive dysfunction. The prevalence of AD is consistently higher in women suggesting they are disproportionately affected by this disease. Despite this, our understanding of this female AD vulnerability remains limited. Menopause has been identified as a potential contributing factor to AD in women, with earlier menopause onset associated with greater AD risk. However, the underlying mechanisms responsible for this increased risk are not fully understood. This review examines the potential role of menopause in the development of Alzheimer's Disease providing a mechanistic overview of the available literature from hormones to pathology. While literature is now emerging that indicates a role of hormonal shifts, gut dysbiosis, lipid dysregulation and inflammation, more research is needed to fully elucidate the mechanisms involved.
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Affiliation(s)
- Bernadette Breeze
- Norwich Medical School, Faculty of Medicine and Health Sciences, University of East Anglia, Norwich NR4 7TJ, United Kingdom
| | - Emily Connell
- Norwich Medical School, Faculty of Medicine and Health Sciences, University of East Anglia, Norwich NR4 7TJ, United Kingdom
| | - Tom Wileman
- Norwich Medical School, Faculty of Medicine and Health Sciences, University of East Anglia, Norwich NR4 7TJ, United Kingdom; Quadram Institute Biosciences, Norwich NR4 7UQ, United Kingdom
| | - Michael Muller
- Norwich Medical School, Faculty of Medicine and Health Sciences, University of East Anglia, Norwich NR4 7TJ, United Kingdom
| | - David Vauzour
- Norwich Medical School, Faculty of Medicine and Health Sciences, University of East Anglia, Norwich NR4 7TJ, United Kingdom
| | - Matthew G Pontifex
- Norwich Medical School, Faculty of Medicine and Health Sciences, University of East Anglia, Norwich NR4 7TJ, United Kingdom.
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3
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Lymer J, Bergman H, Yang S, Mallick R, Galea LAM, Choleris E, Fergusson D. The effects of estrogens on spatial learning and memory in female rodents - A systematic review and meta-analysis. Horm Behav 2024; 164:105598. [PMID: 38968677 DOI: 10.1016/j.yhbeh.2024.105598] [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: 11/16/2023] [Revised: 06/01/2024] [Accepted: 06/19/2024] [Indexed: 07/07/2024]
Abstract
Estrogens have inconsistent effects on learning and memory in both the clinical and preclinical literature. Preclinical literature has the advantage of investigating an array of potentially important factors contributing to the varied effects of estrogens on learning and memory, with stringently controlled studies. This study set out to identify specific factors in the animal literature that influence the effects of estrogens on cognition, for possible translation back to clinical practice. The literature was screened and studies meeting strict inclusion criteria were included in the analysis. Eligible studies included female ovariectomized rodents with an adequate vehicle for the estrogen treatment, with an outcome of spatial learning and memory in the Morris water maze. Training days of the Morris water maze were used to assess acquisition of spatial learning, and the probe trial was used to evaluate spatial memory recall. Continuous outcomes were pooled using a random effects inverse variance method and reported as standardized mean differences with 95 % confidence intervals. Subgroup analyses were developed a priori to assess important factors. The overall analysis favoured treatment for the later stages of training and for the probe trial. Factors including the type of estrogen, route, schedule of administration, age of animals, timing relative to ovariectomy, and duration of treatment were all found to be important. The subgroup analyses showed that chronic treatment with 17β-estradiol, either cyclically or continuously, to young animals improved spatial recall. These results, observed in animals, can inform and guide further clinical research on hormone replacement therapy for cognitive benefits.
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Affiliation(s)
- Jennifer Lymer
- Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada; Division of Neurology, Department of Medicine, The Ottawa Hospital, Ottawa, ON, Canada.
| | - Hailey Bergman
- Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada.
| | - Sabrina Yang
- Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada.
| | | | - Liisa A M Galea
- Department of Psychiatry, University of Toronto, ON, Canada; Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada.
| | - Elena Choleris
- Department of Psychology and Neuroscience Program, University of Guelph, Guelph, ON, Canada.
| | - Dean Fergusson
- Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada; Department of Medicine, University of Ottawa, Ottawa, ON, Canada.
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4
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Koszałka A, Lustyk K, Pytka K. Sex-dependent differences in animal cognition. Neurosci Biobehav Rev 2023; 153:105374. [PMID: 37634555 DOI: 10.1016/j.neubiorev.2023.105374] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 08/17/2023] [Accepted: 08/23/2023] [Indexed: 08/29/2023]
Abstract
The differences in cognitive processes driven by biological sex are the issues that have gotten growing attention recently. Considering the increasing population suffering from various cognitive impairments and the development of therapeutic strategies, it is essential that we recognize the mechanisms responsible for discrepancies observed in male and female learning and memory functions. In this review, we discuss recent reports from preclinical studies on rodents regarding selected cognitive domains to explore the state of knowledge on sex-dependent differences and point to challenges encountered during such research. We focus on spatial, recognition, and emotional memory, as well as on executive functions, such as attention, cognitive flexibility, and working memory. This review will help to acknowledge sex-related differences in cognition and indicate some fields that lack sufficient data.
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Affiliation(s)
- Aleksandra Koszałka
- Jagiellonian University Medical College, Faculty of Pharmacy, Department of Pharmacodynamics, Medyczna 9, 30-688 Krakow, Poland; Jagiellonian University Medical College, Doctoral School of Medical and Health Sciences, Św. Łazarza 16, 31-530 Krakow, Poland
| | - Klaudia Lustyk
- Jagiellonian University Medical College, Faculty of Pharmacy, Department of Pharmacodynamics, Medyczna 9, 30-688 Krakow, Poland
| | - Karolina Pytka
- Jagiellonian University Medical College, Faculty of Pharmacy, Department of Pharmacodynamics, Medyczna 9, 30-688 Krakow, Poland.
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5
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Yagi S, Lieblich SE, Galea LAM. High estradiol reduces adult neurogenesis but strengthens functional connectivity within the hippocampus during spatial pattern separation in adult female rats. Horm Behav 2023; 155:105409. [PMID: 37567060 DOI: 10.1016/j.yhbeh.2023.105409] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 07/19/2023] [Accepted: 07/20/2023] [Indexed: 08/13/2023]
Abstract
Adult neurogenesis in the dentate gyrus plays an important role for pattern separation, the process of separating similar inputs and forming distinct neural representations. Estradiol modulates neurogenesis and hippocampus function, but to date no examination of estradiol's effects on pattern separation have been conducted. Here, we examined estrogenic regulation of adult neurogenesis and functional connectivity in the hippocampus after the spatial pattern separation task in female rats. Ovariectomized Sprague-Dawley rats received daily injections of vehicle, 0.32 μg (Low) or 5 μg (High) of estradiol benzoate until the end of experiment. A single bromodeoxyuridine (BrdU) was injected one day after initiation of hormone or vehicle treatment and rats were tested in the delayed nonmatching to position spatial pattern separation task in the 8-arm radial maze for 12 days beginning two weeks after BrdU injection. Rats were perfused 90 min after the final trial and brain sections were immunohistochemically stained for BrdU/neuronal nuclei (NeuN) (new neurons), Ki67 (cell proliferation), and the immediate early gene, zif268 (activation). Results showed that high, but not low, estradiol reduced the density of BrdU/NeuN-ir cells and had significant inter-regional correlations of zif268-ir cell density in the hippocampus following pattern separation. Estradiol treatment did not influence pattern separation performance or strategy use. These results show that higher doses of estradiol can reduce neurogenesis but at the same time increases correlations of activity of neurons within the hippocampus during spatial pattern separation.
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Affiliation(s)
- Shunya Yagi
- Graduate Program in Neuroscience, University of British Columbia, Vancouver, Canada
| | | | - Liisa A M Galea
- Graduate Program in Neuroscience, University of British Columbia, Vancouver, Canada; Department of Psychology, University of British Columbia, Vancouver, Canada; Djavad Mowifaghian Centre for Brain Health, University of British Columbia, Vancouver, Canada.
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6
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Boueid MJ, El-Hage O, Schumacher M, Degerny C, Tawk M. Zebrafish as an emerging model to study estrogen receptors in neural development. Front Endocrinol (Lausanne) 2023; 14:1240018. [PMID: 37664862 PMCID: PMC10469878 DOI: 10.3389/fendo.2023.1240018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Accepted: 07/27/2023] [Indexed: 09/05/2023] Open
Abstract
Estrogens induce several regulatory signals in the nervous system that are mainly mediated through estrogen receptors (ERs). ERs are largely expressed in the nervous system, yet the importance of ERs to neural development has only been elucidated over the last decades. Accumulating evidence shows a fundamental role for estrogens in the development of the central and peripheral nervous systems, hence, the contribution of ERs to neural function is now a growing area of research. The conservation of the structure of the ERs and their response to estrogens make the zebrafish an interesting model to dissect the role of estrogens in the nervous system. In this review, we highlight major findings of ER signaling in embryonic zebrafish neural development and compare the similarities and differences to research in rodents. We also discuss how the recent generation of zebrafish ER mutants, coupled with the availability of several transgenic reporter lines, its amenability to pharmacological studies and in vivo live imaging, could help us explore ER function in embryonic neural development.
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Affiliation(s)
| | | | | | | | - Marcel Tawk
- *Correspondence: Cindy Degerny, ; Marcel Tawk,
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7
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Hormonal Agents for the Treatment of Depression Associated with the Menopause. Drugs Aging 2022; 39:607-618. [PMID: 35908135 PMCID: PMC9355926 DOI: 10.1007/s40266-022-00962-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/14/2022] [Indexed: 11/29/2022]
Abstract
Perimenopause marks the transition from a woman’s reproductive stage to menopause. Usually occurring between 42 and 52 years of age, it is determined clinically by the onset of irregular menstrual cycles or variable cycle lengths. Women are at an increased risk of depression and anxiety during perimenopause and the menopausal transition. Depressive symptoms experienced in perimenopause are often more severe compared to pre- and post-menopause. During menopausal transition, the impact of fluctuating estrogen in the central nervous system (CNS) can have negative psychological effects for some women. Traditional first-line management of menopausal depression involves antidepressants, with modest outcomes. The positive effects of estrogen treatment in the CNS are becoming increasingly recognised, and hormonal therapy (HT) with estrogen may have a role in the treatment of menopausal depression. In this review we will outline the prevalence, impact and neurochemical basis of menopausal-associated depression, as well as hormone-based approaches that have increasing promise as effective treatments.
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8
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Tomm RJ, Seib DR, Kachkovski GV, Schweitzer HR, Tobiansky DJ, Floresco SB, Soma KK. Androgen synthesis inhibition increases behavioural flexibility and mPFC tyrosine hydroxylase in gonadectomized male rats. J Neuroendocrinol 2022; 34:e13128. [PMID: 35583989 DOI: 10.1111/jne.13128] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 02/15/2022] [Accepted: 03/11/2022] [Indexed: 11/26/2022]
Abstract
Behavioural flexibility is essential to adapt to a changing environment and depends on the medial prefrontal cortex (mPFC). Testosterone administration decreases behavioural flexibility. It is well known that testosterone is produced in the gonads, but testosterone is also produced in the brain, including the mPFC and other nodes of the mesocorticolimbic system. It is unclear how testosterone produced in the brain versus the gonads influences behavioural flexibility. Here, in adult male rats, we assessed the effects of the androgen synthesis inhibitor abiraterone acetate (ABI) and long-term gonadectomy (GDX) on behavioural flexibility in two paradigms. In Experiment 1, ABI but not GDX reduced the number of errors to criterion and perseverative errors in a strategy set-shifting task. In Experiment 2, with a separate cohort of rats, ABI but not GDX reduced perseverative errors in a reversal learning task. In Experiment 1, we also examined tyrosine hydroxylase immunoreactivity (TH-ir), and ABI but not GDX increased TH-ir in the mPFC. Our findings suggest that neurally-produced androgens modulate behavioural flexibility via modification of dopamine signalling in the mesocorticolimbic system. These results indicate that neurosteroids regulate executive functions and that ABI treatment for prostate cancer might affect cognition.
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Affiliation(s)
- Ryan J Tomm
- Department of Psychology and Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, Canada
| | - Désirée R Seib
- Department of Psychology and Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, Canada
| | - George V Kachkovski
- Department of Psychology and Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, Canada
| | - Helen R Schweitzer
- Department of Psychology and Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, Canada
| | - Daniel J Tobiansky
- Department of Psychology and Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, Canada
| | - Stan B Floresco
- Department of Psychology and Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, Canada
| | - Kiran K Soma
- Department of Psychology and Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, Canada
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9
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Hodges TE, Puri TA, Blankers SA, Qiu W, Galea LAM. Steroid hormones and hippocampal neurogenesis in the adult mammalian brain. VITAMINS AND HORMONES 2021; 118:129-170. [PMID: 35180925 DOI: 10.1016/bs.vh.2021.11.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Hippocampal neurogenesis persists across the lifespan in many species, including rodents and humans, and is associated with cognitive performance and the pathogenesis of neurodegenerative disease and psychiatric disorders. Neurogenesis is modulated by steroid hormones that change across development and differ between the sexes in rodents and humans. Here, we discuss the effects of stress and glucocorticoid exposure from gestation to adulthood as well as the effects of androgens and estrogens in adulthood on neurogenesis in the hippocampus. Throughout the review we highlight sex differences in the effects of steroid hormones on neurogenesis and how they may relate to hippocampal function and disease. These data highlight the importance of examining age and sex when evaluating the effects of steroid hormones on hippocampal neurogenesis.
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Affiliation(s)
- Travis E Hodges
- Graduate Program in Neuroscience, University of British Columbia, Vancouver, BC, Canada; Department of Psychology, University of British Columbia, Vancouver, BC, Canada; Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
| | - Tanvi A Puri
- Graduate Program in Neuroscience, University of British Columbia, Vancouver, BC, Canada; Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
| | - Samantha A Blankers
- Graduate Program in Neuroscience, University of British Columbia, Vancouver, BC, Canada; Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
| | - Wansu Qiu
- Graduate Program in Neuroscience, University of British Columbia, Vancouver, BC, Canada; Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
| | - Liisa A M Galea
- Graduate Program in Neuroscience, University of British Columbia, Vancouver, BC, Canada; Department of Psychology, University of British Columbia, Vancouver, BC, Canada; Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada.
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10
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Wan L, Huang RJ, Luo ZH, Gong JE, Pan A, Manavis J, Yan XX, Xiao B. Reproduction-Associated Hormones and Adult Hippocampal Neurogenesis. Neural Plast 2021; 2021:3651735. [PMID: 34539776 PMCID: PMC8448607 DOI: 10.1155/2021/3651735] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 08/17/2021] [Indexed: 11/18/2022] Open
Abstract
The levels of reproduction-associated hormones in females, such as estrogen, progesterone, prolactin, and oxytocin, change dramatically during pregnancy and postpartum. Reproduction-associated hormones can affect adult hippocampal neurogenesis (AHN), thereby regulating mothers' behavior after delivery. In this review, we first briefly introduce the overall functional significance of AHN and the methods commonly used to explore this front. Then, we attempt to reconcile the changes of reproduction-associated hormones during pregnancy. We further update the findings on how reproduction-related hormones influence adult hippocampal neurogenesis. This review is aimed at emphasizing a potential role of AHN in reproduction-related brain plasticity and its neurobiological relevance to motherhood behavior.
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Affiliation(s)
- Lily Wan
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Rou-Jie Huang
- Medical Doctor Program, Xiangya School of Medicine, Central South University, Changsha, China
| | - Zhao-Hui Luo
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Jiao-e Gong
- Department of Neurology, Hunan Children's Hospital, Changsha 410007, China
| | - Aihua Pan
- Department of Anatomy and Neurobiology, Central South University Xiangya School of Medicine, Changsha, Hunan 410013, China
| | - Jim Manavis
- Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, SA, Australia 5000
| | - Xiao-Xin Yan
- Department of Anatomy and Neurobiology, Central South University Xiangya School of Medicine, Changsha, Hunan 410013, China
| | - Bo Xiao
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
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11
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Huckleberry KA, Shansky RM. The unique plasticity of hippocampal adult-born neurons: Contributing to a heterogeneous dentate. Hippocampus 2021; 31:543-556. [PMID: 33638581 DOI: 10.1002/hipo.23318] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 01/15/2021] [Accepted: 02/09/2021] [Indexed: 12/14/2022]
Abstract
The dentate gyrus (DG) of the hippocampus is evolutionarily conserved as one of the few sites of adult neurogenesis in mammals. Although there is clear evidence that neurogenesis is necessary for healthy hippocampal function, whether adult-born neurons are simply integrated into existing hippocampal networks to serve a similar purpose to that of developmentally born neurons or whether they represent a discrete cell population with unique functions remains less clear. In this review, we consider evidence for discrete cellular, synaptic, and structural features of adult-born DG neurons, suggesting that neurogenesis contributes to the formation of a heterogeneous DG. We therefore propose that hippocampal neurogenesis creates a specialized neuronal subpopulation that may play a key role in hippocampal functions like episodic memory. We note critical gaps in this extensive body of work, including a general failure to include female animals in relevant research and a need for more precise consideration of intrahippocampal neuroanatomy.
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Affiliation(s)
- Kylie A Huckleberry
- Behavioral Neuroscience Program, Department of Psychology, Northeastern University, Boston, Massachusetts, USA
| | - Rebecca M Shansky
- Behavioral Neuroscience Program, Department of Psychology, Northeastern University, Boston, Massachusetts, USA
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12
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Adult-Born Neurons in the Hippocampus Are Essential for Social Memory Maintenance. eNeuro 2020; 7:ENEURO.0182-20.2020. [PMID: 33060182 PMCID: PMC7768285 DOI: 10.1523/eneuro.0182-20.2020] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 08/18/2020] [Accepted: 09/30/2020] [Indexed: 01/02/2023] Open
Abstract
Throughout adulthood, the dentate gyrus continues to produce new granule cells, which integrate into the hippocampal circuitry. New neurons have been linked to several known functions of the hippocampus, including learning and memory, anxiety and stress regulation, and social behavior. We explored whether transgenic reduction of adult-born neurons in mice would impair social memory and the formation of social dominance hierarchies. We used a conditional transgenic mouse strain [thymidine kinase (TK) mice] that selectively reduces adult neurogenesis by treatment with the antiviral drug valganciclovir (VGCV). TK mice treated with VGCV were unable to recognize conspecifics as familiar 24 h after initial exposure. We then explored whether reducing new neurons completely impaired their ability to acquire or retrieve a social memory and found that TK mice treated with VGCV were able to perform at control levels when the time between exposure (acquisition) and reexposure (retrieval) was brief. We next explored whether adult-born neurons are involved in dominance hierarchy formation by analyzing their home cage behavior as well as their performance in the tube test, a social hierarchy test, and did not find any consistent alterations in behavior between control and TK mice treated with VGCV. These data suggest that adult neurogenesis is essential for social memory maintenance, but not for acquisition nor retrieval over a short time frame, with no effect on social dominance hierarchy. Future work is needed to explore whether the influence of new neurons on social memory is mediated through connections with the CA2, an area involved in social recognition.
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13
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Martino PL, Cervigni MA, Pulopulos MM, Audisio EO, Bonet JL, De Bortoli MA, Politis DG. Reproductive aging and executive functions in healthy women. AGING NEUROPSYCHOLOGY AND COGNITION 2020; 29:181-196. [PMID: 33307979 DOI: 10.1080/13825585.2020.1859083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
The aim of this study was to analyze the influence of reproductive aging on executive functions. We assessed executive functions in three groups of healthy women in the premenopausal (n = 45, mean age = 30.89, SD = 10.5), perimenopausal (n = 31, mean age = 50.06, SD = 3.6) and postmenopausal (n = 24, mean age = 63.39, SD = 6.5) phase. No differences between groups were observed in working memory, verbal fluency, inhibitory control, planning, and cognitive flexibility. However, when the analyses were repeated with participants with occupations with lower intellectual demands, perimenopausal and postmenopausal women performed worse than premenopausal women in semantic verbal fluency. This study provides important evidence to understand the effects of reproductive aging on cognitive performance in healthy women. Our findings indicate that cognitive reserve-related factors may be important to understand the differences in executive functions associated with reproductive aging.
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Affiliation(s)
- Pablo L Martino
- Rosario Neuroscience Research Center, National University of Rosario, Rosario, Argentina.,National Scientific and Technical Research Council (CONICET), Argentina
| | - Mauricio A Cervigni
- Rosario Neuroscience Research Center, National University of Rosario, Rosario, Argentina.,National Scientific and Technical Research Council (CONICET), Argentina
| | - Matias M Pulopulos
- Department of Experimental Clinical and Health Psychology, Ghent University, Ghent, Belgium.,Department of Psychobiology, National Distance Education University (UNED), Madrid, Spain.,Department of Psychology and Sociology, University of Zaragoza, Zaragoza, Spain
| | - Eduardo O Audisio
- Faculty of Psychology, National University of Rosario, Rosario, Argentina
| | - José L Bonet
- Faculty of Human and Behavioral Sciences, Favaloro University, Buenos Aires, Argentina
| | | | - Daniel G Politis
- National Scientific and Technical Research Council (CONICET), Argentina.,Faculty of Psychology, University of Buenos Aires, Buenos Aires, Argentina
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14
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Hill RA, Kouremenos K, Tull D, Maggi A, Schroeder A, Gibbons A, Kulkarni J, Sundram S, Du X. Bazedoxifene - a promising brain active SERM that crosses the blood brain barrier and enhances spatial memory. Psychoneuroendocrinology 2020; 121:104830. [PMID: 32858306 DOI: 10.1016/j.psyneuen.2020.104830] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Accepted: 08/11/2020] [Indexed: 12/21/2022]
Abstract
Over 20 years of accumulated evidence has shown that the major female sex hormone 17β-estradiol can enhance cognitive functioning. However, the utility of estradiol as a therapeutic cognitive enhancer is hindered by its unwanted peripheral effects (carcinogenic). Selective estrogen receptor modulators (SERMs) avoid the unwanted effects of estradiol by acting as estrogen receptor antagonists in some tissues such as breast and uterus, but as agonists in others such as bone, and are currently used for the treatment of osteoporosis. However, understanding of their actions in the brain are limited. The third generation SERM bazedoxifene has recently been FDA approved for clinical use with an improved biosafety profile. However, whether bazedoxifene can enter the brain and enhance cognition is unknown. Using mice, the current study aimed to explore if bazedoxifene can 1) cross the blood-brain barrier, 2) rescue ovariectomy-induced hippocampal-dependent spatial memory deficit, and 3) activate neural estrogen response element (ERE)-dependent gene transcription. Using liquid chromatography-mass spectrometry (LC-MS), we firstly demonstrate that a peripheral injection of bazedoxifene can enter the brain. Secondly, we show that an acute intraperitoneal injection of bazedoxifene can rescue ovariectomy-induced spatial memory deficits. And finally, using the ERE-luciferase reporter mouse, we show in vivo that bazedoxifene can activate the ERE in the brain. The evidence shown here suggest bazedoxifene could be a viable cognitive enhancer with promising clinical applicability.
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Affiliation(s)
- R A Hill
- Department of Psychiatry, Monash University, Clayton, VIC, 3168, Australia; Florey Institute for Neuroscience and Mental Health, Parkville, VIC, 3052, Australia.
| | - K Kouremenos
- Metabolomics Australia, Bio21 Molecular Science & Biotechnology Institute, Parkville, VIC, 3052, Australia
| | - D Tull
- Metabolomics Australia, Bio21 Molecular Science & Biotechnology Institute, Parkville, VIC, 3052, Australia
| | - A Maggi
- Department of Pharmacological and Biomolecular Sciences, University of Milan, Milan, 20133, Italy
| | - A Schroeder
- Department of Psychiatry, Monash University, Clayton, VIC, 3168, Australia
| | - A Gibbons
- Department of Psychiatry, Monash University, Clayton, VIC, 3168, Australia
| | - J Kulkarni
- Monash Alfred Psychiatry Research Centre, Monash University, St Kilda, VIC, 3004, Australia
| | - S Sundram
- Department of Psychiatry, Monash University, Clayton, VIC, 3168, Australia
| | - X Du
- Department of Psychiatry, Monash University, Clayton, VIC, 3168, Australia; Florey Institute for Neuroscience and Mental Health, Parkville, VIC, 3052, Australia
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15
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Jorgensen C, Wang Z. Hormonal Regulation of Mammalian Adult Neurogenesis: A Multifaceted Mechanism. Biomolecules 2020; 10:biom10081151. [PMID: 32781670 PMCID: PMC7465680 DOI: 10.3390/biom10081151] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Revised: 07/27/2020] [Accepted: 08/01/2020] [Indexed: 02/07/2023] Open
Abstract
Adult neurogenesis—resulting in adult-generated functioning, integrated neurons—is still one of the most captivating research areas of neuroplasticity. The addition of new neurons in adulthood follows a seemingly consistent multi-step process. These neurogenic stages include proliferation, differentiation, migration, maturation/survival, and integration of new neurons into the existing neuronal network. Most studies assessing the impact of exogenous (e.g., restraint stress) or endogenous (e.g., neurotrophins) factors on adult neurogenesis have focused on proliferation, survival, and neuronal differentiation. This review will discuss the multifaceted impact of hormones on these various stages of adult neurogenesis. Specifically, we will review the evidence for hormonal facilitation (via gonadal hormones), inhibition (via glucocorticoids), and neuroprotection (via recruitment of other neurochemicals such as neurotrophin and neuromodulators) on newly adult-generated neurons in the mammalian brain.
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Affiliation(s)
- Claudia Jorgensen
- Behavioral Science Department, Utah Valley University, Orem, UT 84058, USA
- Correspondence:
| | - Zuoxin Wang
- Psychology Department and Program in Neuroscience, Florida State University, Tallahassee, FL 32306, USA;
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16
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Loss of Estrogen Efficacy Against Hippocampus Damage in Long-Term OVX Mice Is Related to the Reduction of Hippocampus Local Estrogen Production and Estrogen Receptor Degradation. Mol Neurobiol 2020; 57:3540-3551. [PMID: 32542593 DOI: 10.1007/s12035-020-01960-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 05/28/2020] [Indexed: 10/24/2022]
Abstract
Postmenopausal women experience a higher risk for neurodegenerative diseases, including cognitive impairment and ischemic stroke. Many preclinical studies have indicated that estrogen replacement therapy (ERT) may provide protective effects against these neurological diseases. However, the results of Women's Health Initiative (WHI) studies have led to the proposal of "critical period hypothesis," which states that there is a precise window of opportunity for administering beneficial hormone therapy following menopause. However, the underlying molecular mechanisms require further characterization. Here, we explored the effects of ERT on cognition decline and global cerebral ischemia (GCI)-induced hippocampal neuronal damage in mice that had experienced both short-term (ovariectomized (OVX) 1 week) and long-term (OVX 10 weeks) estrogen deprivation. We also further explored the concentration of 17β-estradiol (E2) in the circulation and hippocampus and the expression of aromatase and estrogen receptors (ERα, ERα-Ser118, and ERβ). We found that the neuroprotective effectiveness of ERT against hippocampus damage exhibited in OVX1w mice was totally absent in OVX10w mice. Interestingly, the concentration of hippocampal E2 was irreversibly reduced in OVX10w mice, which was related to the decrease of aromatase expression in the hippocampus. In addition, long-term estrogen deprivation (LTED) led to a decrease in estrogen receptor proteins in the hippocampus. Thus, we concluded that the loss of ERT neuroprotection against hippocampus injury in LTED mice was related to the reduction in hippocampus E2 production and estrogen receptor degradation. These results provide several intervention targets to restore the effectiveness of ERT neuroprotection in elderly post-menopausal women.
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17
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Duarte-Guterman P, Lieblich SE, Qiu W, Splinter JEJ, Go KA, Casanueva-Reimon L, Galea LAM. Oxytocin has sex-specific effects on social behaviour and hypothalamic oxytocin immunoreactive cells but not hippocampal neurogenesis in adult rats. Horm Behav 2020; 122:104734. [PMID: 32169583 DOI: 10.1016/j.yhbeh.2020.104734] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 02/06/2020] [Accepted: 02/28/2020] [Indexed: 10/24/2022]
Abstract
Oxytocin regulates social behaviours, pair bonding and hippocampal neurogenesis but most studies have used adult males. Our study investigated the effects of oxytocin on social investigation and adult hippocampal neurogenesis in male and female rats. Oxytocin has poor penetration of the blood-brain barrier, therefore we tested a nanoparticle drug, TRIOZAN™ (Ovensa Inc.), which permits greater blood-brain-barrier penetration. Adult male and female rats were injected daily (i.p.) for 10 days with either: oxytocin in PBS (0.5 or 1.0 mg/kg), oxytocin in TRIOZAN™ (0.5 or 1.0 mg/kg), or vehicle (PBS) and tested for social investigation. Oxytocin decreased body mass and increased social investigation and number of oxytocin-immunoreactive cells in the supraoptic nucleus (SON) of the hypothalamus in male rats only. In both sexes, oxytocin decreased the number of immature neurons (doublecortin+ cells) in the ventral hippocampus and reduced plasma 17β-estradiol levels in a dose- and delivery-dependent way. Oxytocin in TRIOZAN™ reduced "sedation" observed post-injection and increased certain central effects (oxytocin levels in the hypothalamus and neurogenesis in the ventral hippocampus) relative to oxytocin in PBS, indicating that the nanoparticle may be used as an alternative brain delivery system. We showed that oxytocin has sex-specific effects on social investigation, body mass, "sedation", and the oxytocin system. In contrast, similar effects were observed in both sexes in neurogenesis and plasma 17β-estradiol. Our work suggests that sex differences in oxytocin regulation of brain endpoints is region-specific (hypothalamus versus hippocampus) and that oxytocin does not promote social investigation in females.
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Affiliation(s)
- Paula Duarte-Guterman
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada; Department of Psychology, University of British Columbia, Vancouver, BC, Canada
| | - Stephanie E Lieblich
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada; Department of Psychology, University of British Columbia, Vancouver, BC, Canada
| | - Wansu Qiu
- Graduate Program in Neuroscience, University of British Columbia, Vancouver, BC, Canada
| | - Jared E J Splinter
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada; Department of Psychology, University of British Columbia, Vancouver, BC, Canada
| | - Kimberly A Go
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada; Department of Psychology, University of British Columbia, Vancouver, BC, Canada
| | - Laura Casanueva-Reimon
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada; Department of Psychology, University of British Columbia, Vancouver, BC, Canada
| | - Liisa A M Galea
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada; Department of Psychology, University of British Columbia, Vancouver, BC, Canada.
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18
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Eid RS, Lieblich SE, Duarte-Guterman P, Chaiton JA, Mah AG, Wong SJ, Wen Y, Galea LAM. Selective activation of estrogen receptors α and β: Implications for depressive-like phenotypes in female mice exposed to chronic unpredictable stress. Horm Behav 2020; 119:104651. [PMID: 31790664 DOI: 10.1016/j.yhbeh.2019.104651] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2019] [Revised: 11/06/2019] [Accepted: 11/26/2019] [Indexed: 01/19/2023]
Abstract
The estrogen receptor (ER) mechanisms by which 17β-estradiol influences depressive-like behaviour have primarily been investigated acutely and not within an animal model of depression. Therefore, the current study aimed to dissect the contribution of ERα and ERβ to the effects of 17β-estradiol under non-stress and chronic stress conditions. Ovariectomized (OVX) or sham-operated mice were treated chronically (47 days) with 17β-estradiol (E2), the ERβ agonist diarylpropionitrile (DPN), the ERα agonist propylpyrazole-triol (PPT), or vehicle. On day 15 of treatment, mice from each group were assigned to chronic unpredictable stress (CUS; 28 days) or non-CUS conditions. Mice were assessed for anxiety- and depressive-like behaviour and hypothalamic-pituitary-adrenal (HPA) axis function. Cytokine and chemokine levels, and postsynaptic density protein 95 were measured in the hippocampus and frontal cortex, and adult hippocampal neurogenesis was assessed. Overall, the effects of CUS were more robust that those of estrogenic treatments, as seen by increased immobility in the tail suspension test (TST), reduced PSD-95 expression, reduced neurogenesis in the ventral hippocampus, and HPA axis negative feedback dysregulation. However, we also observe CUS-dependent and -independent effects of ovarian status and estrogenic treatments. The effects of CUS on PSD-95 expression, the cytokine milieu, and in TST were largely driven by PPT and DPN, indicating that these treatments were not protective. Independent of CUS, estradiol increased neurogenesis in the dorsal hippocampus, blunted the corticosterone response to an acute stressor, and increased anxiety-like behaviour. These findings provide insights into the complexities of estrogen signaling in modulating depressive-like phenotypes under non-stress and chronic stress conditions.
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Affiliation(s)
- Rand S Eid
- Graduate program in Neuroscience, University of British Columbia, Vancouver, BC, Canada; Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
| | - Stephanie E Lieblich
- Department of Psychology, University of British Columbia, Vancouver, BC, Canada; Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
| | - Paula Duarte-Guterman
- Department of Psychology, University of British Columbia, Vancouver, BC, Canada; Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
| | - Jessica A Chaiton
- Department of Psychology, University of British Columbia, Vancouver, BC, Canada; Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
| | - Amanda G Mah
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
| | - Sarah J Wong
- Department of Psychology, University of British Columbia, Vancouver, BC, Canada; Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
| | - Yanhua Wen
- Department of Psychology, University of British Columbia, Vancouver, BC, Canada; Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
| | - Liisa A M Galea
- Graduate program in Neuroscience, University of British Columbia, Vancouver, BC, Canada; Department of Psychology, University of British Columbia, Vancouver, BC, Canada; Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada.
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19
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Spritzer MD, Roy EA. Testosterone and Adult Neurogenesis. Biomolecules 2020; 10:biom10020225. [PMID: 32028656 PMCID: PMC7072323 DOI: 10.3390/biom10020225] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 01/22/2020] [Accepted: 01/28/2020] [Indexed: 12/16/2022] Open
Abstract
It is now well established that neurogenesis occurs throughout adulthood in select brain regions, but the functional significance of adult neurogenesis remains unclear. There is considerable evidence that steroid hormones modulate various stages of adult neurogenesis, and this review provides a focused summary of the effects of testosterone on adult neurogenesis. Initial evidence came from field studies with birds and wild rodent populations. Subsequent experiments with laboratory rodents have tested the effects of testosterone and its steroid metabolites upon adult neurogenesis, as well as the functional consequences of induced changes in neurogenesis. These experiments have provided clear evidence that testosterone increases adult neurogenesis within the dentate gyrus region of the hippocampus through an androgen-dependent pathway. Most evidence indicates that androgens selectively enhance the survival of newly generated neurons, while having little effect on cell proliferation. Whether this is a result of androgens acting directly on receptors of new neurons remains unclear, and indirect routes involving brain-derived neurotrophic factor (BDNF) and glucocorticoids may be involved. In vitro experiments suggest that testosterone has broad-ranging neuroprotective effects, which will be briefly reviewed. A better understanding of the effects of testosterone upon adult neurogenesis could shed light on neurological diseases that show sex differences.
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Affiliation(s)
- Mark D. Spritzer
- Department of Biology, Middlebury College, Middlebury, VT 05753, USA
- Correspondence: ; Tel.: 802-443-5676
| | - Ethan A. Roy
- Graduate School of Education, Stanford University, Stanford, CA 94305, USA;
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20
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Prolactin, Estradiol and Testosterone Differentially Impact Human Hippocampal Neurogenesis in an In Vitro Model. Neuroscience 2020; 454:15-39. [PMID: 31930958 PMCID: PMC7839971 DOI: 10.1016/j.neuroscience.2019.12.021] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 12/11/2019] [Accepted: 12/12/2019] [Indexed: 12/20/2022]
Abstract
Human hippocampal progenitor cells (HPCs) and tissue express classical sex hormone receptors. Prolactin does not impact human HPCs maintained in a proliferative state. Prolactin increases neuronal differentiation of human HPCs only in the short term. Estradiol and testosterone both increase the cell density of proliferating HPCs. Estradiol and testosterone have no observed effect on differentiating HPCs.
Previous studies have indicated that sex hormones such as prolactin, estradiol and testosterone may play a role in the modulation of adult hippocampal neurogenesis (AHN) in rodents and non-human primates, but so far there has been no investigation of their impact on human hippocampal neurogenesis. Here, we quantify the expression levels of the relevant receptors in human post-mortem hippocampal tissue and a human hippocampal progenitor cell (HPC) line. Secondly, we investigate how these hormones modulate hippocampal neurogenesis using a human in vitro cellular model. Human female HPCs were cultured with biologically relevant concentrations of either prolactin, estradiol or testosterone. Bromodeoxyuridine (BrdU) incorporation, immunocytochemistry (ICC) and high-throughput analyses were used to quantify markers determining cell fate after HPCs were either maintained in a proliferative state or allowed to differentiate in the presence of these hormones. In proliferating cells, estrogen and testosterone increased cell density but had no clear effect on markers of proliferation or cell death to account for this. In differentiating cells, a 3-day treatment of prolactin elicited a transient effect, whereby it increased the proportion of microtubule-associated protein 2 (MAP2)-positive and Doublecortin (DCX)-positive cells, but this effect was not apparent after 7-days. At this timepoint we instead observe a decrease in proliferation. Overall, our study demonstrates relatively minor, and possibly short-term effects of sex hormones on hippocampal neurogenesis in human cells. Further work will be needed to understand if our results differ to previous animal research due to species-specific differences, or whether it relates to limitations of our in vitro model.
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21
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Yare K, Woodward M. Hormone Therapy and Effects on Sporadic Alzheimer’s Disease in Postmenopausal Women: Importance of Nomenclature. J Alzheimers Dis 2020; 73:23-37. [DOI: 10.3233/jad-190896] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Katrine Yare
- Austin Health, Heidelberg Repatriation Hospital, Victoria, Australia
| | - Michael Woodward
- Austin Health, Heidelberg Repatriation Hospital, Victoria, Australia
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22
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Bakhti-Suroosh A, Nesil T, Lynch WJ. Tamoxifen Blocks the Development of Motivational Features of an Addiction-Like Phenotype in Female Rats. Front Behav Neurosci 2019; 13:253. [PMID: 31780909 PMCID: PMC6856674 DOI: 10.3389/fnbeh.2019.00253] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Accepted: 10/23/2019] [Indexed: 12/22/2022] Open
Abstract
Women become addicted sooner after initiating cocaine use as compared to men. Preclinical studies reveal a similar vulnerability in females, with findings from ovariectomized rats suggesting that estradiol mediates the enhanced vulnerability. However, since ovariectomy depletes not only estradiol, but all ovarian hormones, its role in a physiological context is not clear. Thus, the goal of this study was to determine the role of estradiol in the development of an addiction-like phenotype in ovary-intact females treated chronically with the selective estrogen receptor (ER) modulator tamoxifen. We hypothesized that tamoxifen, by antagonizing ERs, would block the development of an addiction-like phenotype as defined by an enhanced motivation for cocaine (assessed under a progressive-ratio schedule), and a heightened vulnerability to relapse (assessed under an extinction/cue-induced reinstatement procedure). Effects were examined following extended access cocaine self-administration (24-h/day; 4-discrete trials/h; 1.5 mg/kg/infusion) and 14-days of abstinence, conditions optimized for inducing an addiction-like phenotype. As predicted, motivation for cocaine was increased following extended-access self-administration and protracted abstinence in the vehicle (sesame oil) and no-injection control groups, but not in the tamoxifen group indicating that ER signaling is critical for the development of this feature of an addiction-like phenotype. Surprisingly, the increase in motivation for cocaine following abstinence was also attenuated in the vehicle group as compared to no-injection controls suggesting that oil/injections also affected its development. Contrary to our hypothesis, tamoxifen did not decrease vulnerability to relapse as this group responded at similar levels during initial extinction sessions and cue-induced reinstatement testing as compared to controls. Tamoxifen did, however, impair extinction learning as this group took longer to extinguish as compared to controls. Taken together, these findings indicate that estradiol is critical for the extinction of drug-associated cues and the development of motivational features of addiction.
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Affiliation(s)
- Anousheh Bakhti-Suroosh
- Department of Psychiatry and Neurobehavioral Sciences, University of Virginia, Charlottesville, VA, United States
| | - Tanseli Nesil
- Department of Psychiatry and Neurobehavioral Sciences, University of Virginia, Charlottesville, VA, United States
| | - Wendy J Lynch
- Department of Psychiatry and Neurobehavioral Sciences, University of Virginia, Charlottesville, VA, United States
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23
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Dorsal Hippocampal Actin Polymerization Is Necessary for Activation of G-Protein-Coupled Estrogen Receptor (GPER) to Increase CA1 Dendritic Spine Density and Enhance Memory Consolidation. J Neurosci 2019; 39:9598-9610. [PMID: 31628182 DOI: 10.1523/jneurosci.2687-18.2019] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 09/03/2019] [Accepted: 10/13/2019] [Indexed: 11/21/2022] Open
Abstract
Activation of the membrane estrogen receptor G-protein-coupled estrogen receptor (GPER) in ovariectomized mice via the GPER agonist G-1 mimics the beneficial effects of 17β-estradiol (E2) on hippocampal CA1 spine density and memory consolidation, yet the cell-signaling mechanisms mediating these effects remain unclear. The present study examined the role of actin polymerization and c-Jun N-terminal kinase (JNK) phosphorylation in mediating effects of dorsal hippocampally infused G-1 on CA1 dendritic spine density and consolidation of object recognition and spatial memories in ovariectomized mice. We first showed that object learning increased apical CA1 spine density in the dorsal hippocampus (DH) within 40 min. We then found that DH infusion of G-1 increased both CA1 spine density and phosphorylation of the actin polymerization regulator cofilin, suggesting that activation of GPER may increase spine morphogenesis through actin polymerization. As with memory consolidation in our previous work (Kim et al., 2016), effects of G-1 on CA1 spine density and cofilin phosphorylation depended on JNK phosphorylation in the DH. Also consistent with our previous findings, E2-induced cofilin phosphorylation was not dependent on GPER activation. Finally, we found that infusion of the actin polymerization inhibitor, latrunculin A, into the DH prevented G-1 from increasing apical CA1 spine density and enhancing both object recognition and spatial memory consolidation. Collectively, these data demonstrate that GPER-mediated hippocampal spinogenesis and memory consolidation depend on JNK and cofilin signaling, supporting a critical role for actin polymerization in the GPER-induced regulation of hippocampal function in female mice.SIGNIFICANCE STATEMENT Emerging evidence suggests that G-protein-coupled estrogen receptor (GPER) activation mimics effects of 17β-estradiol on hippocampal memory consolidation. Unlike canonical estrogen receptors, GPER activation is associated with reduced cancer cell proliferation; thus, understanding the molecular mechanisms through which GPER regulates hippocampal function may provide new avenues for the development of drugs that provide the cognitive benefits of estrogens without harmful side effects. Here, we demonstrate that GPER increases CA1 dendritic spine density and hippocampal memory consolidation in a manner dependent on actin polymerization and c-Jun N-terminal kinase phosphorylation. These findings provide novel insights into the role of GPER in mediating hippocampal morphology and memory consolidation, and may suggest first steps toward new therapeutics that more safely and effectively reduce memory decline in menopausal women.
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24
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Hillerer KM, Slattery DA, Pletzer B. Neurobiological mechanisms underlying sex-related differences in stress-related disorders: Effects of neuroactive steroids on the hippocampus. Front Neuroendocrinol 2019; 55:100796. [PMID: 31580837 PMCID: PMC7115954 DOI: 10.1016/j.yfrne.2019.100796] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [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.
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Affiliation(s)
- Katharina M Hillerer
- Department of Obstetrics and Gynaecology, Salzburger Landeskrankenhaus (SALK), Paracelsus Medical University (PMU), Clinical Research Center Salzburg (CRCS), Salzburg, Austria.
| | - David A Slattery
- Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, University Hospital, Goethe University, Frankfurt, Germany
| | - Belinda Pletzer
- Department of Psychology, University of Salzburg, Salzburg, Austria; Centre for Cognitive Neuroscience, University of Salzburg, Salzburg, Austria
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25
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The Impact of Estradiol on Neurogenesis and Cognitive Functions in Alzheimer's Disease. Cell Mol Neurobiol 2019; 40:283-299. [PMID: 31502112 DOI: 10.1007/s10571-019-00733-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 08/31/2019] [Indexed: 12/18/2022]
Abstract
Alzheimer's disease (AD) is described as cognitive and memory impairments with a sex-related epidemiological profile, affecting two times more women than men. There is emerging evidence that alternations in the hippocampal neurogenesis occur at the early stage of AD. Therapies that may effectively slow, stop, or regenerate the dying neurons in AD are being extensively investigated in the last few decades, but none has yet been found to be effective. The regulation of endogenous neurogenesis is one of the main therapeutic targets for AD. Mounting evidence indicates that the neurosteroid estradiol (17β-estradiol) plays a supporting role in neurogenesis, neuronal activity, and synaptic plasticity of AD. This effect may provide preventive and/or therapeutic approaches for AD. In this article, we discuss the molecular mechanism of potential estradiol modulatory action on endogenous neurogenesis, synaptic plasticity, and cognitive function in AD.
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26
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Taxier LR, Philippi SM, Fortress AM, Frick KM. Dickkopf-1 blocks 17β-estradiol-enhanced object memory consolidation in ovariectomized female mice. Horm Behav 2019; 114:104545. [PMID: 31228421 PMCID: PMC6732224 DOI: 10.1016/j.yhbeh.2019.06.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Revised: 06/15/2019] [Accepted: 06/16/2019] [Indexed: 01/05/2023]
Abstract
The memory-enhancing effects of 17β-estradiol (E2) depend upon rapid activation of several cell-signaling cascades within the dorsal hippocampus (DH). Among the many cell-signaling pathways that mediate memory processes, Wnt/β-catenin signaling has emerged as a potential key player because of its importance to hippocampal development and synaptic plasticity. However, whether E2 interacts with Wnt/β-catenin signaling to promote memory consolidation is unknown. Therefore, the present study examined whether Wnt/β-catenin signaling within the DH is necessary for E2-induced memory consolidation in ovariectomized mice tested in the object recognition and object placement tasks. Ovariectomized C57BL/6 mice received immediate post-training infusions of E2 or vehicle into the dorsal third ventricle plus the endogenous Wnt/β-catenin antagonist Dickkopf-1 (Dkk-1) or vehicle into the DH to assess whether the memory-enhancing effects of E2 depend on activation of Wnt/β-catenin signaling. Our results suggest that Dkk-1 blocks E2-induced memory enhancement as hypothesized, but may do so by only moderately blunting Wnt/β-catenin signaling while concurrently activating Wnt/JNK signaling. The current study provides novel insights into the mechanisms through which E2 enhances memory consolidation in the DH, as well as critical information about the mechanistic actions of Dkk-1.
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Affiliation(s)
- Lisa R Taxier
- Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, United States.
| | - Sarah M Philippi
- Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, United States.
| | - Ashley M Fortress
- V.A. Pittsburgh Healthcare System, Pittsburgh, PA 15216, United States.
| | - Karyn M Frick
- Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, United States.
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27
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Lambert K, Eisch AJ, Galea LAM, Kempermann G, Merzenich M. Optimizing brain performance: Identifying mechanisms of adaptive neurobiological plasticity. Neurosci Biobehav Rev 2019; 105:60-71. [PMID: 31356835 DOI: 10.1016/j.neubiorev.2019.06.033] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 06/18/2019] [Accepted: 06/24/2019] [Indexed: 01/19/2023]
Abstract
Although neuroscience research has debunked the late 19th century claims suggesting that large portions of the brain are typically unused, recent evidence indicates that an enhanced understanding of neural plasticity may lead to greater insights related to the functional capacity of brains. Continuous and real-time neural modifications in concert with dynamic environmental contexts provide opportunities for targeted interventions for maintaining healthy brain functions throughout the lifespan. Neural design, however, is far from simplistic, requiring close consideration of context-specific and other relevant variables from both species and individual perspectives to determine the functional gains from increased and decreased markers of neuroplasticity. Caution must be taken in the interpretation of any measurable change in neurobiological responses or behavioral outcomes, as definitions of optimal functions are extremely complex. Even so, current behavioral neuroscience approaches offer unique opportunities to evaluate adaptive functions of various neural responses in an attempt to enhance the functional capacity of neural systems.
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Affiliation(s)
- Kelly Lambert
- Dept of Psychology, B326 Gottwald Science Center, University of Richmond, VA, 23173, USA.
| | - Amelia J Eisch
- Dept of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104-4399, USA.
| | - Liisa A M Galea
- Dept of Psychology, University of British Columbia, 2136 West Mall, Vancouver, BC V6T, Canada.
| | - Gerd Kempermann
- German Center for Neurodegenerative Diseases (DZNE) Dresden and CRTD-Center for Regenerative Therapies Dresden at Technische Universität Dresden, 01307 Dresden, Germany.
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28
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Sheppard PAS, Choleris E, Galea LAM. Structural plasticity of the hippocampus in response to estrogens in female rodents. Mol Brain 2019; 12:22. [PMID: 30885239 PMCID: PMC6423800 DOI: 10.1186/s13041-019-0442-7] [Citation(s) in RCA: 105] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 03/11/2019] [Indexed: 01/05/2023] Open
Abstract
It is well established that estrogens affect neuroplasticity in a number of brain regions. In particular, estrogens modulate and mediate spine and synapse formation as well as neurogenesis in the hippocampal formation. In this review, we discuss current research exploring the effects of estrogens on dendritic spine plasticity and neurogenesis with a focus on the modulating factors of sex, age, and pregnancy. Hormone levels, including those of estrogens, fluctuate widely across the lifespan from early life to puberty, through adulthood and into old age, as well as with pregnancy and parturition. Dendritic spine formation and modulation are altered both by rapid (likely non-genomic) and classical (genomic) actions of estrogens and have been suggested to play a role in the effects of estrogens on learning and memory. Neurogenesis in the hippocampus is influenced by age, the estrous cycle, pregnancy, and parity in female rodents. Furthermore, sex differences exist in hippocampal cellular and molecular responses to estrogens and are briefly discussed throughout. Understanding how structural plasticity in the hippocampus is affected by estrogens and how these effects can influence function and be influenced by other factors, such as experience and sex, is critical and can inform future treatments in conditions involving the hippocampus.
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Affiliation(s)
- Paul A. S. Sheppard
- Department of Psychology, Graduate Program in Neuroscience, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC V6T 1Z3 Canada
| | - Elena Choleris
- Department of Psychology & Neuroscience Program, University of Guelph, Guelph, ON N1G 2W1 Canada
| | - Liisa A. M. Galea
- Department of Psychology, Graduate Program in Neuroscience, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC V6T 1Z3 Canada
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29
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Atwood CS, Ekstein SF. Human versus non-human sex steroid use in hormone replacement therapies part 1: Preclinical data. Mol Cell Endocrinol 2019; 480:12-35. [PMID: 30308266 DOI: 10.1016/j.mce.2018.10.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Revised: 03/12/2018] [Accepted: 10/04/2018] [Indexed: 11/24/2022]
Abstract
Prior to 2002, hormone replacement therapy (HRT) was considered to be an important component of postmenopausal healthcare. This was based on a plethora of basic, epidemiological and clinical studies demonstrating the health benefits of supplementation with human sex steroids. However, adverse findings from the Women's Health Initiative (WHI) studies that examined the 2 major forms of HRT in use in the US at that time - Premarin (conjugated equine estrogens; CEE) and Prempro (CEE + medroxyprogesterone acetate; MPA), cast a shadow over the use of any form of HRT. Here we review the biochemical and physiological differences between the non-human WHI study hormones - CEE and MPA, and their respective human counterparts 17β-estradiol (E2) and progesterone (P4). Preclinical data from the last 30 years demonstrate clear differences between human and non-human sex steroids on numerous molecular, physiological and functional parameters in brain, heart and reproductive tissue. In contrast to CEE supplementation, which is not always detrimental although certainly not as optimal as E2 supplementation, MPA is clearly not equivalent to P4, having detrimental effects on cognitive, cardiac and reproductive function. Moreover, unlike P4, MPA is clearly antagonistic of the positive effects of E2 and CEE on tissue function. These data indicate that minor chemical changes to human sex steroids result in physiologically distinct actions that are not optimal for tissue health and functioning.
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Affiliation(s)
- Craig S Atwood
- Division of Geriatrics and Gerontology, Department of Medicine, University of Wisconsin-Madison School of Medicine and Public Health, USA; Geriatric Research, Education and Clinical Center, Veterans Administration Hospital, Madison, WI, 53705, USA; School of Exercise, Biomedical and Health Sciences, Edith Cowan University, Joondalup, 6027, WA, Australia.
| | - Samuel F Ekstein
- Division of Geriatrics and Gerontology, Department of Medicine, University of Wisconsin-Madison School of Medicine and Public Health, USA
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30
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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.
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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
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31
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Galea LA, Roes MM, Dimech CJ, Chow C, Mahmoud R, Lieblich SE, Duarte-Guterman P. Premarin has opposing effects on spatial learning, neural activation, and serum cytokine levels in middle-aged female rats depending on reproductive history. Neurobiol Aging 2018; 70:291-307. [DOI: 10.1016/j.neurobiolaging.2018.06.030] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 06/23/2018] [Accepted: 06/24/2018] [Indexed: 01/28/2023]
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ERα and/or ERβ activation ameliorates cognitive impairment, neurogenesis and apoptosis in type 2 diabetes mellitus mice. Exp Neurol 2018; 311:33-43. [PMID: 30201537 DOI: 10.1016/j.expneurol.2018.09.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 08/30/2018] [Accepted: 09/05/2018] [Indexed: 12/17/2022]
Abstract
Estrogen receptors (ERs) are thought to be associated with the onset and progression of neurodegenerative injuries and diseases, but the relationship and mechanisms underlying between ERs and cognition in type 2 diabetes remain elusive. In the current study, we investigated the effects of ERα and ERβ on the cognition, neurogenesis and apoptosis in high-fat diet and streptozocin-induced diabetic mice. We found that ERα and/or ERβ activation using their agonists (0.5 mg/kg E2, PPT or DPN) ameliorate memory impairment in the Morris water maze and Y-maze tests, increase hippocampal neurogenesis and prevent hippocampal apoptotic responses. Importantly, treatment with the pharmacologic ERs agonists caused significant increases in the membrane ERα and ERβ expression and subsequent PI3K/Akt, CREB and BDNF activation in the hippocampus of type 2 diabetes mellitus mice. Our data indicate that ERα and ERβ are involved in the cognitive impairment in type 2 diabetes, and that activated ERs, such as application of ERs agonists, could be a novel and promising strategy for the treatment of diabetic cognitive impairment.
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33
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Nemeth VL, Must A, Horvath S, Király A, Kincses ZT, Vécsei L. Gender-Specific Degeneration of Dementia-Related Subcortical Structures Throughout the Lifespan. J Alzheimers Dis 2018; 55:865-880. [PMID: 27792015 DOI: 10.3233/jad-160812] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Age-related changes in brain structure are a question of interest to a broad field of research. Structural decline has been consistently, but not unambiguously, linked to functional consequences, including cognitive impairment and dementia. One of the areas considered of crucial importance throughout this process is the medial temporal lobe, and primarily the hippocampal region. Gender also has a considerable effect on volume deterioration of subcortical grey matter (GM) structures, such as the hippocampus. The influence of age×gender interaction on disproportionate GM volume changes might be mediated by hormonal effects on the brain. Hippocampal volume loss appears to become accelerated in the postmenopausal period. This decline might have significant influences on neuroplasticity in the CA1 region of the hippocampus highly vulnerable to pathological influences. Additionally, menopause has been associated with critical pathobiochemical changes involved in neurodegeneration. The micro- and macrostructural alterations and consequent functional deterioration of critical hippocampal regions might result in clinical cognitive impairment-especially if there already is a decline in the cognitive reserve capacity. Several lines of potential vulnerability factors appear to interact in the menopausal period eventually leading to cognitive decline, mild cognitive impairment, or Alzheimer's disease. This focused review aims to delineate the influence of unmodifiable risk factors of neurodegenerative processes, i.e., age and gender, on critical subcortical GM structures in the light of brain derived estrogen effects. The menopausal period appears to be of key importance for the risk of cognitive decline representing a time of special vulnerability for molecular, structural, and functional influences and offering only a narrow window for potential protective effects.
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Affiliation(s)
- Viola Luca Nemeth
- Department of Neurology, Albert Szent-Györgyi Clinical Center, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Anita Must
- Department of Neurology, Albert Szent-Györgyi Clinical Center, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Szatmar Horvath
- Department of Psychiatry, Albert Szent-Györgyi Clinical Center, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Andras Király
- Department of Neurology, Albert Szent-Györgyi Clinical Center, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Zsigmond Tamas Kincses
- Department of Neurology, Albert Szent-Györgyi Clinical Center, Faculty of Medicine, University of Szeged, Szeged, Hungary.,International Clinical Research Center, St. Anne's University Hospital Brno, Brno, Czech Republic
| | - László Vécsei
- Department of Neurology, Albert Szent-Györgyi Clinical Center, Faculty of Medicine, University of Szeged, Szeged, Hungary.,MTA-SZTE Neuroscience Research Group, Szeged, Hungary
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34
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Gheorghe A, Qiu W, Galea LAM. Hormonal Regulation of Hippocampal Neurogenesis: Implications for Depression and Exercise. Curr Top Behav Neurosci 2018; 43:379-421. [PMID: 30414016 DOI: 10.1007/7854_2018_62] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Adult hippocampal neurogenesis exists in all mammalian species, including humans, and although there has been considerable research investigating the function and regulation of neurogenesis, there remain many open questions surrounding the complexity of this phenomenon. This stems partially from the fact that neurogenesis is a multistage process that involves proliferation, differentiation, migration, survival, and eventual integration of new cells into the existing hippocampal circuitry, each of which can be independently influenced. The function of adult neurogenesis in the hippocampus is related to stress regulation, behavioral efficacy of antidepressants, long-term spatial memory, forgetting, and pattern separation. Steroid hormones influence the regulation of hippocampal neurogenesis, stress regulation, and cognition and differently in males and females. In this chapter, we will briefly tap into the complex network of steroid hormone modulation of neurogenesis in the hippocampus with specific emphasis on stress, testosterone, and estrogen. We examine the possible role of neurogenesis in the etiology of depression and influencing treatment by examining the influence of both pharmacological (selective serotonin reuptake inhibitors, tricyclic antidepressants) treatments and non-pharmacological (exercise) remedies.
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Affiliation(s)
- Ana Gheorghe
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada.,Graduate Program in Neuroscience, University of British Columbia, Vancouver, BC, Canada
| | - Wansu Qiu
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada.,Graduate Program in Neuroscience, University of British Columbia, Vancouver, BC, Canada
| | - Liisa A M Galea
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada. .,Graduate Program in Neuroscience, University of British Columbia, Vancouver, BC, Canada. .,Department of Psychology, University of British Columbia, Vancouver, BC, Canada.
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35
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Engler-Chiurazzi EB, Brown CM, Povroznik JM, Simpkins JW. Estrogens as neuroprotectants: Estrogenic actions in the context of cognitive aging and brain injury. Prog Neurobiol 2017; 157:188-211. [PMID: 26891883 PMCID: PMC4985492 DOI: 10.1016/j.pneurobio.2015.12.008] [Citation(s) in RCA: 136] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 11/06/2015] [Accepted: 12/10/2015] [Indexed: 12/30/2022]
Abstract
There is ample empirical evidence to support the notion that the biological impacts of estrogen extend beyond the gonads to other bodily systems, including the brain and behavior. Converging preclinical findings have indicated a neuroprotective role for estrogen in a variety of experimental models of cognitive function and brain insult. However, the surprising null or even detrimental findings of several large clinical trials evaluating the ability of estrogen-containing hormone treatments to protect against age-related brain changes and insults, including cognitive aging and brain injury, led to hesitation by both clinicians and patients in the use of exogenous estrogenic treatments for nervous system outcomes. That estrogen-containing therapies are used by tens of millions of women for a variety of health-related applications across the lifespan has made identifying conditions under which benefits with estrogen treatment will be realized an important public health issue. Here we provide a summary of the biological actions of estrogen and estrogen-containing formulations in the context of aging, cognition, stroke, and traumatic brain injury. We have devoted special attention to highlighting the notion that estrogen appears to be a conditional neuroprotectant whose efficacy is modulated by several interacting factors. By developing criteria standards for desired beneficial peripheral and neuroprotective outcomes among unique patient populations, we can optimize estrogen treatments for attenuating the consequences of, and perhaps even preventing, cognitive aging and brain injury.
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Affiliation(s)
- E B Engler-Chiurazzi
- Center for Basic and Translational Stroke Research, West Virginia University, Morgantown, WV 26506, United States; Department of Physiology and Pharmacology, West Virginia University, Morgantown, WV 26506, United States.
| | - C M Brown
- Center for Basic and Translational Stroke Research, West Virginia University, Morgantown, WV 26506, United States; Department of Neurobiology and Anatomy, West Virginia University, Morgantown, WV 26506, United States.
| | - J M Povroznik
- Center for Basic and Translational Stroke Research, West Virginia University, Morgantown, WV 26506, United States; Department of Pediatrics, West Virginia University, Morgantown, WV 26506, United States.
| | - J W Simpkins
- Center for Basic and Translational Stroke Research, West Virginia University, Morgantown, WV 26506, United States; Department of Physiology and Pharmacology, West Virginia University, Morgantown, WV 26506, United States.
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36
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Urbanski HF, Sorwell KG, Prokai L, Kohama SG. Effect of short-term DHEA supplementation on serum and hippocampal estrogen concentrations in perimenopausal female rhesus macaques. Neurobiol Aging 2017; 55:172-174. [PMID: 28431754 PMCID: PMC5443113 DOI: 10.1016/j.neurobiolaging.2017.03.026] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 03/21/2017] [Accepted: 03/23/2017] [Indexed: 11/30/2022]
Abstract
The hippocampus of rhesus macaques expresses genes that encode key enzymes involved in the intracrine conversion of dehydroepiandrosterone (DHEA) to estradiol. Therefore, it is plausible that supplementary DHEA may enhance hippocampal estradiol concentrations and help to compensate for the marked postmenopausal attenuation of circulating estrogen levels. To test this hypothesis, we used LC-MS/MS to measure estradiol and estrone concentrations in the serum and hippocampus of young and old perimenopausal female rhesus macaques, as well as old perimenopausal females that received daily DHEA (5 mg) oral supplementation for 1 week. Despite lower concentrations of these estrogens in the serum of the older animals, their concentrations in the hippocampus did not show any obvious differences due to age or to DHEA supplementation. The results suggest that de novo estrogen synthesis in the brain may compensate for the perimenopausal loss of estrogens in the circulation even without supplemental DHEA.
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Affiliation(s)
- Henryk F Urbanski
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR, USA; Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR, USA; Department of Physiology & Pharmacology, Oregon Health & Science University, Portland, OR, USA; Division of Reproductive & Developmental Sciences, Oregon National Primate Research Center, Beaverton, OR, USA.
| | - Krystina G Sorwell
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR, USA; Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR, USA
| | - Laszlo Prokai
- Center for Neuroscience Discovery, Institute for Healthy Aging, University of North Texas Health Science Center, Fort Worth, TX, USA
| | - Steven G Kohama
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR, USA
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37
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Yagi S, Drewczynski D, Wainwright SR, Barha CK, Hershorn O, Galea LAM. Sex and estrous cycle differences in immediate early gene activation in the hippocampus and the dorsal striatum after the cue competition task. Horm Behav 2017; 87:69-79. [PMID: 27984032 DOI: 10.1016/j.yhbeh.2016.10.019] [Citation(s) in RCA: 28] [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: 05/13/2016] [Revised: 09/29/2016] [Accepted: 10/28/2016] [Indexed: 12/28/2022]
Abstract
The hippocampus and dorsal striatum are important structures involved in place and response learning strategies respectively. Both sex and estrous cycle phase differences in learning strategy preference exist following cue competition paradigms. Furthermore, significant effects of sex and learning strategy on hippocampal neural plasticity have been reported. However, associations between learning strategy and immediate early gene (IEG) expression in the hippocampus and dorsal striatum are not completely understood. In the current study we investigated the effects of sex and estrous cycle phase on strategy choice and IEG expression in the hippocampus and dorsal striatum of rats following cue competition training in the Morris water maze. We found that proestrous rats were more likely to choose a place strategy than non-proestrous or male rats. Although male cue strategy users travelled greater distances than the other groups on the first day of training, there were no other sex or strategy differences in the ability to reach a hidden or a visible platform. Female place strategy users exhibited greater zif268 expression and male place strategy users exhibited greater cFos expression compared to all other groups in CA3. Furthermore, cue strategy users had greater expression of cFos in the dorsal striatum than place strategy users. Shorter distances to reach a visible platform were associated with less activation of cFos in CA3 and CA1 of male place strategy users. Our findings indicate multiple differences in brain activation with sex and strategy use, despite limited behavioral differences between the sexes on this cue competition paradigm.
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Affiliation(s)
- Shunya Yagi
- Graduate Program in Neuroscience, University of British Columbia, Vancouver, Canada
| | - Dimka Drewczynski
- Department of Psychology, University of British Columbia, Vancouver, Canada
| | - Steven R Wainwright
- Graduate Program in Neuroscience, University of British Columbia, Vancouver, Canada
| | - Cindy K Barha
- Department of Psychology, University of British Columbia, Vancouver, Canada
| | - Olivia Hershorn
- Department of Psychology, University of British Columbia, Vancouver, Canada
| | - Liisa A M Galea
- Graduate Program in Neuroscience, University of British Columbia, Vancouver, Canada; Department of Psychology, University of British Columbia, Vancouver, Canada; Centre for Brain Health, University of British Columbia, Vancouver, Canada.
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38
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Koss WA, Frick KM. Sex differences in hippocampal function. J Neurosci Res 2016; 95:539-562. [DOI: 10.1002/jnr.23864] [Citation(s) in RCA: 99] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Revised: 06/28/2016] [Accepted: 07/11/2016] [Indexed: 12/25/2022]
Affiliation(s)
- Wendy A. Koss
- Department of Psychology; University of Wisconsin-Milwaukee; Milwaukee Wisconsin
| | - Karyn M. Frick
- Department of Psychology; University of Wisconsin-Milwaukee; Milwaukee Wisconsin
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39
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Brus M, Trouillet AC, Hellier V, Bakker J. Estradiol-induced neurogenesis in the female accessory olfactory bulb is required for the learning of the male odor. J Neurochem 2016; 138:457-68. [PMID: 27216894 DOI: 10.1111/jnc.13677] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Revised: 04/20/2016] [Accepted: 05/12/2016] [Indexed: 01/05/2023]
Abstract
Odors processed by the main and accessory olfactory bulbs (MOB, AOB) are important for sexual behavior. Interestingly, both structures continue to receive new neurons during adulthood. A role for olfactory neurogenesis in sexual behavior in female mice has recently been shown and gonadal hormones such as estradiol can modulate adult neurogenesis. Therefore, we wanted to determine the role of estradiol in learning the odors of sexual partners and in the adult neurogenesis of female aromatase knockout mice (ArKO), unable to produce estradiol. Female wild-type (WT) and ArKO mice were exposed to male odors during 7 days, and olfactory preferences, cell proliferation, cell survival and functional involvement of newborn neurons were analyzed, using BrdU injections, in combination with a marker of cell activation (Zif268) and neuronal fate (doublecortin, NeuN). Behavioral tasks indicated that both WT and ArKO females were able to discriminate between the odors of two different males, but ArKO mice failed to learn the familiar male odor. Proliferation of newborn cells was reduced in ArKO mice only in the dentate gyrus of the hippocampus. Olfactory exposure decreased cell survival in the AOB in WT females, suggesting a role for estradiol in a structure involved in sexual behavior. Finally, newborn neurons do not seem to be functionally involved in the AOB of ArKO mice compared with WT, when females were exposed to the odor of a familiar male, suggesting that estradiol-induced neurogenesis in the AOB is required for the learning of the male odor in female mice. Aromatase knockout mice (ArKO) presented deficits in olfactory preferences without affecting their olfactory discrimination abilities, and showed no functional involvement of newborn neurons in the accessory olfactory bulb (AOB) in response to the odor of a familiar male. These results suggest that estradiol-induced neurogenesis in the female AOB is required for the learning of the male odor.
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Affiliation(s)
- Maïna Brus
- Laboratory of Neuroendocrinology, Groupe Interdisciplinaire de Génoprotéomique Appliquée (GIGA) Neurosciences, University of Liège, Liège, Belgium
| | - Anne-Charlotte Trouillet
- Laboratory of Neuroendocrinology, Groupe Interdisciplinaire de Génoprotéomique Appliquée (GIGA) Neurosciences, University of Liège, Liège, Belgium
| | - Vincent Hellier
- Laboratory of Neuroendocrinology, Groupe Interdisciplinaire de Génoprotéomique Appliquée (GIGA) Neurosciences, University of Liège, Liège, Belgium
| | - Julie Bakker
- Laboratory of Neuroendocrinology, Groupe Interdisciplinaire de Génoprotéomique Appliquée (GIGA) Neurosciences, University of Liège, Liège, Belgium
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40
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Hamson DK, Roes MM, Galea LAM. Sex Hormones and Cognition: Neuroendocrine Influences on Memory and Learning. Compr Physiol 2016; 6:1295-337. [DOI: 10.1002/cphy.c150031] [Citation(s) in RCA: 118] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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41
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Schiller CE, Johnson SL, Abate AC, Schmidt PJ, Rubinow DR. Reproductive Steroid Regulation of Mood and Behavior. Compr Physiol 2016; 6:1135-60. [PMID: 27347888 PMCID: PMC6309888 DOI: 10.1002/cphy.c150014] [Citation(s) in RCA: 108] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
In this article, we examine evidence supporting the role of reproductive steroids in the regulation of mood and behavior in women and the nature of that role. In the first half of the article, we review evidence for the following: (i) the reproductive system is designed to regulate behavior; (ii) from the subcellular to cellular to circuit to behavior, reproductive steroids are powerful neuroregulators; (iii) affective disorders are disorders of behavioral state; and (iv) reproductive steroids affect virtually every system implicated in the pathophysiology of depression. In the second half of the article, we discuss the diagnosis of the three reproductive endocrine-related mood disorders (premenstrual dysphoric disorder, postpartum depression, and perimenopausal depression) and present evidence supporting the relevance of reproductive steroids to these conditions. Existing evidence suggests that changes in reproductive steroid levels during specific reproductive states (i.e., the premenstrual phase of the menstrual cycle, pregnancy, parturition, and the menopause transition) trigger affective dysregulation in susceptible women, thus suggesting the etiopathogenic relevance of these hormonal changes in reproductive mood disorders. Understanding the source of individual susceptibility is critical to both preventing the onset of illness and developing novel, individualized treatments for reproductive-related affective dysregulation. © 2016 American Physiological Society. Compr Physiol 6:1135-1160, 2016e.
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Affiliation(s)
- Crystal Edler Schiller
- Psychiatry Department, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Sarah L. Johnson
- Psychiatry Department, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Anna C. Abate
- Psychiatry Department, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Peter J. Schmidt
- Section on Behavioral Endocrinology, National Institute of Mental Health, Department of Health and Human Services, Bethesda, Maryland, USA
| | - David R. Rubinow
- Psychiatry Department, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
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42
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The effects of hormones and physical exercise on hippocampal structural plasticity. Front Neuroendocrinol 2016; 41:23-43. [PMID: 26989000 DOI: 10.1016/j.yfrne.2016.03.001] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 03/02/2016] [Accepted: 03/08/2016] [Indexed: 01/22/2023]
Abstract
The hippocampus plays an integral role in certain aspects of cognition. Hippocampal structural plasticity and in particular adult hippocampal neurogenesis can be influenced by several intrinsic and extrinsic factors. Here we review how hormones (i.e., intrinsic modulators) and physical exercise (i.e., an extrinsic modulator) can differentially modulate hippocampal plasticity in general and adult hippocampal neurogenesis in particular. Specifically, we provide an overview of the effects of sex hormones, stress hormones, and metabolic hormones on hippocampal structural plasticity and adult hippocampal neurogenesis. In addition, we also discuss how physical exercise modulates these forms of hippocampal plasticity, giving particular emphasis on how this modulation can be affected by variables such as exercise regime, duration, and intensity. Understanding the neurobiological mechanisms underlying the modulation of hippocampal structural plasticity by intrinsic and extrinsic factors will impact the design of new therapeutic approaches aimed at restoring hippocampal plasticity following brain injury or neurodegeneration.
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43
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Mahmoud R, Wainwright SR, Galea LAM. Sex hormones and adult hippocampal neurogenesis: Regulation, implications, and potential mechanisms. Front Neuroendocrinol 2016; 41:129-52. [PMID: 26988999 DOI: 10.1016/j.yfrne.2016.03.002] [Citation(s) in RCA: 127] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 03/12/2016] [Accepted: 03/14/2016] [Indexed: 11/16/2022]
Abstract
Neurogenesis within the adult hippocampus is modulated by endogenous and exogenous factors. Here, we review the role of sex hormones in the regulation of adult hippocampal neurogenesis in males and females. The review is framed around the potential functional implications of sex hormone regulation of adult hippocampal neurogenesis, with a focus on cognitive function and mood regulation, which may be related to sex differences in incidence and severity of dementia and depression. We present findings from preclinical studies of endogenous fluctuations in sex hormones relating to reproductive function and ageing, and from studies of exogenous hormone manipulations. In addition, we discuss the modulating roles of sex, age, and reproductive history on the relationship between sex hormones and neurogenesis. Because sex hormones have diverse targets in the central nervous system, we overview potential mechanisms through which sex hormones may influence hippocampal neurogenesis. Lastly, we advocate for a more systematic consideration of sex and sex hormones in studying the functional implications of adult hippocampal neurogenesis.
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Affiliation(s)
- Rand Mahmoud
- Graduate Program in Neuroscience, University of British Columbia, Vancouver, Canada
| | - Steven R Wainwright
- Graduate Program in Neuroscience, University of British Columbia, Vancouver, Canada
| | - Liisa A M Galea
- Department of Psychology, University of British Columbia, Vancouver, Canada; Centre for Brain Health, University of British Columbia, Vancouver, Canada.
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44
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Slattery DA, Hillerer KM. The maternal brain under stress: Consequences for adaptive peripartum plasticity and its potential functional implications. Front Neuroendocrinol 2016; 41:114-28. [PMID: 26828151 DOI: 10.1016/j.yfrne.2016.01.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Revised: 01/22/2016] [Accepted: 01/27/2016] [Indexed: 12/25/2022]
Abstract
The peripartum period represents a time during which all mammalian species undergo substantial physiological and behavioural changes, which prepare the female for the demands of motherhood. In addition to behavioural and physiological alterations, numerous brain regions, such as the medial prefrontal cortex, olfactory bulb, medial amygdala and hippocampus are subject to substantial peripartum-associated neuronal, dendritic and synaptic plasticity. These changes, which are temporally- and spatially-distinct, are strongly influenced by gonadal and adrenal hormones, such as estrogen and cortisol/corticosterone, which undergo dramatic fluctuations across this period. In this review, we describe our current knowledge regarding these plasticity changes and describe how stress affects such normal adaptations. Finally, we discuss the mechanisms potentially underlying these neuronal, dendritic and synaptic changes and their functional relevance for the mother and her offspring.
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Affiliation(s)
- David A Slattery
- Department of Behavioural and Molecular Neurobiology, University of Regensburg, Regensburg, Germany
| | - Katharina M Hillerer
- Department of Obstetrics and Gynaecology, Salzburger Landeskrankenhaus (SALK), Paracelsus Medical University, Salzburg, Austria
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45
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Social behavior, hormones and adult neurogenesis. Front Neuroendocrinol 2016; 41:71-86. [PMID: 26996817 DOI: 10.1016/j.yfrne.2016.02.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Revised: 02/08/2016] [Accepted: 02/11/2016] [Indexed: 01/31/2023]
Abstract
A variety of experiences have been shown to affect the production of neurons in the adult hippocampus. These effects may be mediated by experience-driven hormonal changes, which, in turn, interact with factors such as sex, age and life history to alter brain plasticity. Although the effects of physical experience and stress have been extensively characterized, various types of social experience across the lifespan trigger profound neuroendocrine changes in parallel with changes in adult neurogenesis. This review article focuses on the influence of specific social experiences on adult neurogenesis in the dentate gyrus and the potential role of hormones in these effects.
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Galea LAM, Frick KM, Hampson E, Sohrabji F, Choleris E. Why estrogens matter for behavior and brain health. Neurosci Biobehav Rev 2016; 76:363-379. [PMID: 27039345 PMCID: PMC5045786 DOI: 10.1016/j.neubiorev.2016.03.024] [Citation(s) in RCA: 110] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Revised: 03/21/2016] [Accepted: 03/29/2016] [Indexed: 12/22/2022]
Abstract
The National Institutes of Health (NIH) has required the inclusion of women in clinical studies since 1993, which has enhanced our understanding of how biological sex affects certain medical conditions and allowed the development of sex-specific treatment protocols. However, NIH's policy did not previously apply to basic research, and the NIH recently introduced a new policy requiring all new grant applications to explicitly address sex as a biological variable. The policy itself is grounded in the results of numerous investigations in animals and humans illustrating the existence of sex differences in the brain and behavior, and the importance of sex hormones, particularly estrogens, in regulating physiology and behavior. Here, we review findings from our laboratories, and others, demonstrating how estrogens influence brain and behavior in adult females. Research from subjects throughout the adult lifespan on topics ranging from social behavior, learning and memory, to disease risk will be discussed to frame an understanding of why estrogens matter to behavioral neuroscience.
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Affiliation(s)
- Liisa A M Galea
- Department of Psychology, Centre for Brain Health, University of British Columbia, Vancouver, BC V6T1Z4, Canada.
| | - Karyn M Frick
- Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, United States
| | - Elizabeth Hampson
- Department of Psychology, University of Western Ontario, London, ON N6A 5C2, Canada
| | - Farida Sohrabji
- Department of Neuroscience and Experimental Therapeutics, Texas A&M HSC College of Medicine, Bryan, TX 77807, United States
| | - Elena Choleris
- Department of Psychology and Neuroscience Program, University of Guelph, Guelph, ON N1G 2W1, Canada
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47
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Gender Differences in the Neurobiology of Anxiety: Focus on Adult Hippocampal Neurogenesis. Neural Plast 2016; 2016:5026713. [PMID: 26885403 PMCID: PMC4738969 DOI: 10.1155/2016/5026713] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Revised: 11/30/2015] [Accepted: 12/06/2015] [Indexed: 12/14/2022] Open
Abstract
Although the literature reports a higher incidence of anxiety disorders in women, the majority of basic research has focused on male rodents, thus resulting in a lack of knowledge on the neurobiology of anxiety in females. Bridging this gap is crucial for the design of effective translational interventions in women. One of the key brain mechanisms likely to regulate anxious behavior is adult hippocampal neurogenesis (AHN). This review paper aims to discuss the evidence on the differences between male and female rodents with regard to anxiety-related behavior and physiology, with a special focus on AHN. The differences between male and female physiologies are greatly influenced by hormonal differences. Gonadal hormones and their fluctuations during the estrous cycle have often been identified as agents responsible for sexual dimorphism in behavior and AHN. During sexual maturity, hormone levels fluctuate cyclically in females more than in males, increasing the stress response and the susceptibility to anxiety. It is therefore of great importance that future research investigates anxiety and other neurophysiological aspects in the female model, so that results can be more accurately applicable to the female population.
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48
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BE360, a new selective estrogen receptor modulator, produces antidepressant and antidementia effects through the enhancement of hippocampal cell proliferation in olfactory bulbectomized mice. Behav Brain Res 2016; 297:315-22. [DOI: 10.1016/j.bbr.2015.10.033] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2015] [Revised: 09/02/2015] [Accepted: 10/15/2015] [Indexed: 02/08/2023]
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49
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Frick KM, Kim J, Tuscher JJ, Fortress AM. Sex steroid hormones matter for learning and memory: estrogenic regulation of hippocampal function in male and female rodents. Learn Mem 2015; 22:472-93. [PMID: 26286657 PMCID: PMC4561402 DOI: 10.1101/lm.037267.114] [Citation(s) in RCA: 137] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Accepted: 07/09/2015] [Indexed: 01/24/2023]
Abstract
Ample evidence has demonstrated that sex steroid hormones, such as the potent estrogen 17β-estradiol (E2), affect hippocampal morphology, plasticity, and memory in male and female rodents. Yet relatively few investigators who work with male subjects consider the effects of these hormones on learning and memory. This review describes the effects of E2 on hippocampal spinogenesis, neurogenesis, physiology, and memory, with particular attention paid to the effects of E2 in male rodents. The estrogen receptors, cell-signaling pathways, and epigenetic processes necessary for E2 to enhance memory in female rodents are also discussed in detail. Finally, practical considerations for working with female rodents are described for those investigators thinking of adding females to their experimental designs.
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Affiliation(s)
- Karyn M Frick
- Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53211, USA
| | - Jaekyoon Kim
- Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53211, USA
| | - Jennifer J Tuscher
- Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53211, USA
| | - Ashley M Fortress
- Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53211, USA
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50
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Yagi S, Chow C, Lieblich SE, Galea LAM. Sex and strategy use matters for pattern separation, adult neurogenesis, and immediate early gene expression in the hippocampus. Hippocampus 2015; 26:87-101. [PMID: 26179150 DOI: 10.1002/hipo.22493] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/06/2015] [Indexed: 12/12/2022]
Abstract
Adult neurogenesis in the dentate gyrus (DG) plays a crucial role for pattern separation, and there are sex differences in the regulation of neurogenesis. Although sex differences, favoring males, in spatial navigation have been reported, it is not known whether there are sex differences in pattern separation. The current study was designed to determine whether there are sex differences in the ability for separating similar or distinct patterns, learning strategy choice, adult neurogenesis, and immediate early gene (IEG) expression in the DG in response to pattern separation training. Male and female Sprague-Dawley rats received a single injection of the DNA synthesis marker, bromodeoxyuridine (BrdU), and were tested for the ability of separating spatial patterns in a spatial pattern separation version of delayed nonmatching to place task using the eight-arm radial arm maze. Twenty-seven days following BrdU injection, rats received a probe trial to determine whether they were idiothetic or spatial strategy users. We found that male spatial strategy users outperformed female spatial strategy users only when separating similar, but not distinct, patterns. Furthermore, male spatial strategy users had greater neurogenesis in response to pattern separation training than all other groups. Interestingly, neurogenesis was positively correlated with performance on similar pattern trials during pattern separation in female spatial strategy users but negatively correlated with performance in male idiothetic strategy users. These results suggest that the survival of new neurons may play an important positive role for pattern separation of similar patterns in females. Furthermore, we found sex and strategy differences in IEG expression in the CA1 and CA3 regions in response to pattern separation. These findings emphasize the importance of studying biological sex on hippocampal function and neural plasticity.
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Affiliation(s)
- Shunya Yagi
- Graduate Program in Neuroscience, University of British Columbia, Vancouver, British Columbia, Canada
| | - Carmen Chow
- Department of Psychology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Stephanie E Lieblich
- Department of Psychology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Liisa A M Galea
- Graduate Program in Neuroscience, University of British Columbia, Vancouver, British Columbia, Canada.,Department of Psychology, University of British Columbia, Vancouver, British Columbia, Canada.,Centre for Brain Health, University of British Columbia, Vancouver, British Columbia, Canada
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