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Zuloaga DG, Lafrican JJ, Zuloaga KL. Androgen regulation of behavioral stress responses and the hypothalamic-pituitary-adrenal axis. Horm Behav 2024; 162:105528. [PMID: 38503191 PMCID: PMC11144109 DOI: 10.1016/j.yhbeh.2024.105528] [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: 12/11/2023] [Revised: 02/02/2024] [Accepted: 03/06/2024] [Indexed: 03/21/2024]
Abstract
Testosterone is a powerful steroid hormone that can impact the brain and behavior in various ways, including regulating behavioral and neuroendocrine (hypothalamic-pituitary-adrenal (HPA) axis) stress responses. Early in life androgens can act to alter development of brain regions associated with stress regulation, which ultimately impacts the display of stress responses later in life. Adult circulating androgens can also influence the expression of distinct genes and proteins that regulate stress responses. These changes in the brain are hypothesized to underlie the potent effects of androgens in regulating behaviors related to stress and stress-induced activation of the HPA axis. Androgens can induce alterations in these functions through direct binding to the androgen receptor (AR) or following conversion to estrogens and subsequent binding to estrogen receptors including estrogen receptor alpha (ERα), beta (ERβ), and G protein-coupled estrogen receptor 1 (GPER1). In this review, we focus on the role of androgens in regulating behavioral and neuroendocrine stress responses at different stages of the lifespan and the sex hormone receptors involved in regulating these effects. We also review the specific brain regions and cell phenotypes upon which androgens are proposed to act to regulate stress responses with an emphasis on hypothalamic and extended amygdala subregions. This knowledge of androgen effects on these neural systems is critical for understanding how sex hormones regulate stress responses.
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Affiliation(s)
- Damian G Zuloaga
- Department of Psychology, University at Albany, Albany, NY, USA.
| | | | - Kristen L Zuloaga
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, NY, USA
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2
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Edwards M, Lam S, Ranjan R, Pereira M, Babbitt C, Lacreuse A. Letrozole treatment alters hippocampal gene expression in common marmosets (Callithrix jacchus). Horm Behav 2023; 147:105281. [PMID: 36434852 PMCID: PMC9839488 DOI: 10.1016/j.yhbeh.2022.105281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Revised: 10/28/2022] [Accepted: 11/09/2022] [Indexed: 11/25/2022]
Abstract
Aromatase inhibitors (AIs) are a class of drugs commonly given to patients with estrogen receptor (ER)-dependent breast cancers to reduce estrogenic stimulation. However, AIs like Letrozole are associated with negative side effects such as cognitive deficits, sleep disturbances and hot flashes. We have previously shown that these negative effects can be recapitulated in common marmosets (Callithrix jacchus) treated with Letrozole (20 μg daily) for 4 weeks and that marmosets treated with Letrozole show increased levels of estradiol in the hippocampus (Gervais et al., 2019). In order to better understand the mechanisms through which AIs affect cognitive function and increase steroid levels in the hippocampus, we used bulk, paired-end RNA-sequencing to examine differentially expressed genes among Letrozole-treated (LET; n = 8) and vehicle-treated (VEH; n = 8) male and female animals. Gene ontology results show significant reduction across hundreds of categories, some of the most significant being inflammatory response, stress response, MHC Class II protein complex binding, T-cell activation, carbohydrate binding and signaling receptor binding in LET animals. GSEA results indicate that LET females, but not LET males, show enrichment for hormonal gene sets. Based on the transcriptional changes observed, we conclude that AIs may differentially affect the sexes in part due to processes mediated by the CYP-450 superfamily. Ongoing studies will further investigate the longitudinal effects of AIs on behavior and whether AIs increase the risk of stress-induced neurodegeneration.
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Affiliation(s)
- Mélise Edwards
- University of Massachusetts Amherst, Department of Psychological & Brain Sciences, Amherst, MA 01003, USA; Neuroscience and Behavior Graduate Program, University of Massachusetts, Amherst, MA 01003, USA.
| | - Sam Lam
- University of Massachusetts Amherst, Department of Psychological & Brain Sciences, Amherst, MA 01003, USA
| | - Ravi Ranjan
- University of Massachusetts Amherst, Department of Psychological & Brain Sciences, Amherst, MA 01003, USA; Genomics Resource Laboratory, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Mariana Pereira
- University of Massachusetts Amherst, Department of Psychological & Brain Sciences, Amherst, MA 01003, USA; Neuroscience and Behavior Graduate Program, University of Massachusetts, Amherst, MA 01003, USA
| | - Courtney Babbitt
- University of Massachusetts Amherst, Department of Psychological & Brain Sciences, Amherst, MA 01003, USA; University of Massachusetts Amherst, Department of Biology, Amherst, MA 01003, USA
| | - Agnès Lacreuse
- University of Massachusetts Amherst, Department of Psychological & Brain Sciences, Amherst, MA 01003, USA; Neuroscience and Behavior Graduate Program, University of Massachusetts, Amherst, MA 01003, USA
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3
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Colettis NC, Habif M, Oberholzer MV, Filippin F, Jerusalinsky DA. Differences in learning and memory between middle-aged female and male rats. Learn Mem 2022; 29:120-125. [PMID: 35428728 PMCID: PMC9053109 DOI: 10.1101/lm.053578.122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 03/23/2022] [Indexed: 11/24/2022]
Abstract
We observed differences in cognitive functions between middle-aged female and male Wistar rats. Both (like youngsters) discriminated new versus familiar objects, showing similar short- and long-term memory (STM and LTM, respectively). Only females show robust LTM for new location of an object. Both successfully form LTM of inhibitory avoidance, though males appeared to be amnesic for memory persistence. Habituation, locomotion, horizontal exploration, "stereotypies," fear, and anxiety-like behavior were similar for both, while vertical exploration was significantly higher in middle-aged and younger females. Therefore, sex-dependent differences in some cognitive functions and behaviors must be considered when designing and interpreting learning and memory studies.
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Affiliation(s)
- Natalia Claudia Colettis
- Laboratorio de Neuroplasticidad y Neurotoxinas (LaN&N), Instituto de Biología Celular y Neurociencia (IBCN) "Prof. Eduardo De Robertis" (Universidad de Buenos Aires-Consejo Nacional de Investigaciones Científicas y Técnicas), Facultad de Medicina, Buenos Aires C1121ABG, Argentina.,Instituto de Química y Fisicoquímica Biológicas Prof. Dr. Alejandro C. Paladini, (Universidad de Buenos Aires-Consejo Nacional de Investigaciones Científicas y Técnicas), Facultad de Farmacia y Bioquímica. Buenos Aires C1113AAD, Argentina
| | - Martín Habif
- Laboratorio de Neuroplasticidad y Neurotoxinas (LaN&N), Instituto de Biología Celular y Neurociencia (IBCN) "Prof. Eduardo De Robertis" (Universidad de Buenos Aires-Consejo Nacional de Investigaciones Científicas y Técnicas), Facultad de Medicina, Buenos Aires C1121ABG, Argentina
| | - María Victoria Oberholzer
- Laboratorio de Neuroplasticidad y Neurotoxinas (LaN&N), Instituto de Biología Celular y Neurociencia (IBCN) "Prof. Eduardo De Robertis" (Universidad de Buenos Aires-Consejo Nacional de Investigaciones Científicas y Técnicas), Facultad de Medicina, Buenos Aires C1121ABG, Argentina
| | - Federico Filippin
- Laboratorio de Neuroplasticidad y Neurotoxinas (LaN&N), Instituto de Biología Celular y Neurociencia (IBCN) "Prof. Eduardo De Robertis" (Universidad de Buenos Aires-Consejo Nacional de Investigaciones Científicas y Técnicas), Facultad de Medicina, Buenos Aires C1121ABG, Argentina
| | - Diana Alicia Jerusalinsky
- Laboratorio de Neuroplasticidad y Neurotoxinas (LaN&N), Instituto de Biología Celular y Neurociencia (IBCN) "Prof. Eduardo De Robertis" (Universidad de Buenos Aires-Consejo Nacional de Investigaciones Científicas y Técnicas), Facultad de Medicina, Buenos Aires C1121ABG, Argentina
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4
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Spool JA, Bergan JF, Remage-Healey L. A neural circuit perspective on brain aromatase. Front Neuroendocrinol 2022; 65:100973. [PMID: 34942232 PMCID: PMC9667830 DOI: 10.1016/j.yfrne.2021.100973] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 12/14/2021] [Accepted: 12/16/2021] [Indexed: 12/23/2022]
Abstract
This review explores the role of aromatase in the brain as illuminated by a set of conserved network-level connections identified in several vertebrate taxa. Aromatase-expressing neurons are neurochemically heterogeneous but the brain regions in which they are found are highly-conserved across the vertebrate lineage. During development, aromatase neurons have a prominent role in sexual differentiation of the brain and resultant sex differences in behavior and human brain diseases. Drawing on literature primarily from birds and rodents, we delineate brain regions that express aromatase and that are strongly interconnected, and suggest that, in many species, aromatase expression essentially defines the Social Behavior Network. Moreover, in several cases the inputs to and outputs from this core Social Behavior Network also express aromatase. Recent advances in molecular and genetic tools for neuroscience now enable in-depth and taxonomically diverse studies of the function of aromatase at the neural circuit level.
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Affiliation(s)
- Jeremy A Spool
- Center for Neuroendocrine Studies, Neuroscience and Behavior Graduate Program, University of Massachusetts, Amherst, MA 01003, United States
| | - Joseph F Bergan
- Center for Neuroendocrine Studies, Neuroscience and Behavior Graduate Program, University of Massachusetts, Amherst, MA 01003, United States
| | - Luke Remage-Healey
- Center for Neuroendocrine Studies, Neuroscience and Behavior Graduate Program, University of Massachusetts, Amherst, MA 01003, United States.
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5
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Ellis SN, Honeycutt JA. Sex Differences in Affective Dysfunction and Alterations in Parvalbumin in Rodent Models of Early Life Adversity. Front Behav Neurosci 2021; 15:741454. [PMID: 34803622 PMCID: PMC8600234 DOI: 10.3389/fnbeh.2021.741454] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 10/13/2021] [Indexed: 01/08/2023] Open
Abstract
The early life environment markedly influences brain and behavioral development, with adverse experiences associated with increased risk of anxiety and depressive phenotypes, particularly in females. Indeed, early life adversity (ELA) in humans (i.e., caregiver deprivation, maltreatment) and rodents (i.e., maternal separation, resource scarcity) is associated with sex-specific emergence of anxious and depressive behaviors. Although these disorders show clear sex differences in humans, little attention has been paid toward evaluating sex as a biological variable in models of affective dysfunction; however, recent rodent work suggests sex-specific effects. Two widely used rodent models of ELA approximate caregiver deprivation (i.e., maternal separation) and resource scarcity (i.e., limited bedding). While these approaches model aspects of ELA experienced in humans, they span different portions of the pre-weaning developmental period and may therefore differentially contribute to underlying mechanistic risk. This is borne out in the literature, where evidence suggests differences in trajectories of behavior depending on the type of ELA and/or sex; however, the neural underpinning of these differences is not well understood. Because anxiety and depression are thought to involve dysregulation in the balance of excitatory and inhibitory signaling in ELA-vulnerable brain regions (e.g., prefrontal cortex, amygdala, hippocampus), outcomes are likely driven by alterations in local and/or circuit-specific inhibitory activity. The most abundant GABAergic subtypes in the brain, accounting for approximately 40% of inhibitory neurons, contain the calcium-binding protein Parvalbumin (PV). As PV-expressing neurons have perisomatic and proximal dendritic targets on pyramidal neurons, they are well-positioned to regulate excitatory/inhibitory balance. Recent evidence suggests that PV outcomes following ELA are sex, age, and region-specific and may be influenced by the type and timing of ELA. Here, we suggest the possibility of a combined role of PV and sex hormones driving differences in behavioral outcomes associated with affective dysfunction following ELA. This review evaluates the literature across models of ELA to characterize neural (PV) and behavioral (anxiety- and depressive-like) outcomes as a function of sex and age. Additionally, we detail a putative mechanistic role of PV on ELA-related outcomes and discuss evidence suggesting hormone influences on PV expression/function which may help to explain sex differences in ELA outcomes.
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Affiliation(s)
- Seneca N Ellis
- Program in Neuroscience, Bowdoin College, Brunswick, ME, United States
| | - Jennifer A Honeycutt
- Program in Neuroscience, Bowdoin College, Brunswick, ME, United States.,Department of Psychology, Bowdoin College, Brunswick, ME, United States
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6
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Renczés E, Borbélyová V, Steinhardt M, Höpfner T, Stehle T, Ostatníková D, Celec P. The Role of Estrogen in Anxiety-Like Behavior and Memory of Middle-Aged Female Rats. Front Endocrinol (Lausanne) 2020; 11:570560. [PMID: 33117285 PMCID: PMC7575693 DOI: 10.3389/fendo.2020.570560] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 09/02/2020] [Indexed: 12/21/2022] Open
Abstract
Aging in women is associated with low estrogen, but also with cognitive decline and affective disorders. Whether low estrogen is causally responsible for these behavioral symptoms is not clear. Thus, we aimed to examine the role of estradiol in anxiety-like behavior and memory in rats at middle age. Twelve-month old female rats underwent ovariectomy (OVX) or were treated with 1 mg/kg of letrozole-an aromatase inhibitor. In half of the OVX females, 10 μg/kg of 17β-estradiol was supplemented daily for 4 weeks. Vehicle-treated sham-operated and OVX females served as controls. For behavioral assessment open field, elevated plus maze and novel object recognition tests were performed. Interaction between ovarian condition and additional treatment had the main effect on anxiety-like behavior of rats in the open field test. In comparison to control females, OVX females entered less frequently into the center zone of the open field (p < 0.01) and showed lower novel object discrimination (p = 0.05). However, estradiol-supplemented OVX rats had higher number of center-zone entries (p < 0.01), spent more time in the center zone (p < 0.05), and showed lower thigmotaxis (p < 0.01) when compared to OVX group. None of the hormonal manipulations affected anxiety-like behavior in the elevated plus maze test significantly, but a mild effect of interaction between ovarian condition and treatment was shown (p = 0.05). In conclusion, ovariectomy had slight negative effect on open-field ambulation and short-term recognition memory in middle-aged rats. In addition, a test-specific anxiolytic effect of estradiol supplementation was found. In contrast, letrozole treatment neither affected anxiety-like behavior nor memory.
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Affiliation(s)
- Emese Renczés
- Institute of Molecular Biomedicine, Faculty of Medicine, Comenius University in Bratislava, Bratislava, Slovakia
| | - Veronika Borbélyová
- Institute of Molecular Biomedicine, Faculty of Medicine, Comenius University in Bratislava, Bratislava, Slovakia
| | - Manuel Steinhardt
- Institute of Molecular Biomedicine, Faculty of Medicine, Comenius University in Bratislava, Bratislava, Slovakia
| | - Tim Höpfner
- Institute of Molecular Biomedicine, Faculty of Medicine, Comenius University in Bratislava, Bratislava, Slovakia
| | - Thomas Stehle
- Institute of Molecular Biomedicine, Faculty of Medicine, Comenius University in Bratislava, Bratislava, Slovakia
| | - Daniela Ostatníková
- Institute of Physiology, Faculty of Medicine, Comenius University in Bratislava, Bratislava, Slovakia
| | - Peter Celec
- Institute of Molecular Biomedicine, Faculty of Medicine, Comenius University in Bratislava, Bratislava, Slovakia
- Institute of Pathophysiology, Faculty of Medicine, Comenius University in Bratislava, Bratislava, Slovakia
- Department of Molecular Biology, Faculty of Natural Sciences, Comenius University in Bratislava, Bratislava, Slovakia
- *Correspondence: Peter Celec
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7
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Azcoitia I, Barreto GE, Garcia-Segura LM. Molecular mechanisms and cellular events involved in the neuroprotective actions of estradiol. Analysis of sex differences. Front Neuroendocrinol 2019; 55:100787. [PMID: 31513774 DOI: 10.1016/j.yfrne.2019.100787] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 08/27/2019] [Accepted: 09/07/2019] [Indexed: 12/12/2022]
Abstract
Estradiol, either from peripheral or central origin, activates multiple molecular neuroprotective and neuroreparative responses that, being mediated by estrogen receptors or by estrogen receptor independent mechanisms, are initiated at the membrane, the cytoplasm or the cell nucleus of neural cells. Estrogen-dependent signaling regulates a variety of cellular events, such as intracellular Ca2+ levels, mitochondrial respiratory capacity, ATP production, mitochondrial membrane potential, autophagy and apoptosis. In turn, these molecular and cellular actions of estradiol are integrated by neurons and non-neuronal cells to generate different tissue protective responses, decreasing blood-brain barrier permeability, oxidative stress, neuroinflammation and excitotoxicity and promoting synaptic plasticity, axonal growth, neurogenesis, remyelination and neuroregeneration. Recent findings indicate that the neuroprotective and neuroreparative actions of estradiol are different in males and females and further research is necessary to fully elucidate the causes for this sex difference.
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Affiliation(s)
- Iñigo Azcoitia
- Department of Cell Biology, Faculty of Biology, Universidad Complutense de Madrid, 28040 Madrid, Spain; Centro de Investigación Biomédica en Red Fragilidad y Envejecimiento Saludables (CIBERFES), Instituto de Salud Carlos III, Avenida Monforte de Lemos, 3-5, 28029 Madrid, Spain.
| | - George E Barreto
- Department of Biological Sciences, School of Natural Sciences, University of Limerick, Limerick, Ireland.
| | - Luis M Garcia-Segura
- Centro de Investigación Biomédica en Red Fragilidad y Envejecimiento Saludables (CIBERFES), Instituto de Salud Carlos III, Avenida Monforte de Lemos, 3-5, 28029 Madrid, Spain; Instituto Cajal, CSIC, Avenida Doctor Arce 37, 28002 Madrid, Spain.
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8
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Chronic aromatase inhibition increases ventral hippocampal neurogenesis in middle-aged female mice. Psychoneuroendocrinology 2019; 106:111-116. [PMID: 30974324 DOI: 10.1016/j.psyneuen.2019.04.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 04/02/2019] [Indexed: 12/21/2022]
Abstract
Letrozole, a third-generation aromatase inhibitor, prevents the production of estrogens in the final step in conversion from androgens. Due to its efficacy at suppressing estrogens, letrozole has recently taken favor as a first-line adjuvant treatment for hormone-responsive breast cancer in middle-aged women. Though patient response to letrozole has generally been positive, there is conflicting evidence surrounding its effects on the development of depression. It is possible that the potential adverse effects of letrozole on mood are a result of the impact of hormonal fluctuations on neurogenesis in the hippocampus. Thus, to clarify the effects of letrozole on the hippocampus and behavior, we examined how chronic administration affects hippocampal neurogenesis and depressive-like behavior in middle-aged, intact female mice. Mice were given either letrozole (1 mg/kg) or vehicle by injection (i.p.) daily for 3 weeks. Depressive-like behavior was assessed during the last 3 days of treatment using the forced swim test, tail suspension test, and sucrose preference test. The production of new neurons was quantified using the immature neuronal marker doublecortin (DCX), and cell proliferation was quantified using the endogenous marker Ki67. We found that letrozole increased DCX and Ki67 expression and maturation in the dentate gyrus, but had no significant effect on depressive-like behavior. Our findings suggest that a reduction in estrogens in middle-aged females increases hippocampal neurogenesis without any adverse impact on depressive-like behavior; as such, this furthers our understanding of how estrogens modulate neurogenesis, and to the rationale for the utilization of letrozole in the clinical management of breast cancer.
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Liu JP. Aging mechanisms and intervention targets. Clin Exp Pharmacol Physiol 2019; 44 Suppl 1:3-8. [PMID: 29178613 DOI: 10.1111/1440-1681.12896] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 11/21/2017] [Indexed: 01/01/2023]
Abstract
Premature aging occurs frequently to various tissues and organs resulting in the tissue-specific chronic diseases. The mechanisms of tissue-specific premature aging are largely unknown. In response to environmental cues, aging may originate from cytoplasm or the nucleus of a cell with cytoplasm aging in association with organelle degeneration in terminally differentiated cells and nuclear aging with dysfunctional telomeres and irreversible cell cycle arrest in stem and cancer cells. Either cytoplasm aging or nuclear aging may cause extracellular senescence-associated low-grade inflammation to spread aging. Referring to the recent findings in this special issue of Healthy Aging in CEPP and beyond, we describe the molecular and cellular mechanisms of physiological aging and tissue-specific pathological aging in chronic diseases.
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Affiliation(s)
- Jun-Ping Liu
- School of Medicine, Institute of Ageing Research, Hangzhou Normal University, Hangzhou, Zhejiang Province, China.,Department of Immunology, Faculty of Medicine, Central Clinical School, Monash University, Prahran, VIC, Australia.,Hudson Institute of Medical Research and Department of Molecular and Translational Science, Faculty of Medicine, Monash University, Clayton, VIC, Australia
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10
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Shay DA, Vieira-Potter VJ, Rosenfeld CS. Sexually Dimorphic Effects of Aromatase on Neurobehavioral Responses. Front Mol Neurosci 2018; 11:374. [PMID: 30374289 PMCID: PMC6196265 DOI: 10.3389/fnmol.2018.00374] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2018] [Accepted: 09/21/2018] [Indexed: 01/16/2023] Open
Abstract
Aromatase is the enzyme responsible for converting testosterone to estradiol. In mammals, aromatase is expressed in the testes, ovaries, brain, and other tissues. While estrogen is traditionally associated with reproduction and sexual behavior in females, our current understanding broadens this perspective to include such biological functions as metabolism and cognition. It is now well-recognized that aromatase plays a vital lifetime role in brain development and neurobehavioral function in both sexes. Thus, ongoing investigations seek to highlight potentially vital sex differences in the role of aromatase, particularly regarding its centrally mediated effects. To characterize the role of aromatase in mediating such functions, effects of aromatase inhibitor (AI) treatments on humans and animal models have been determined. Aromatase knockout (ArKO) mice that systemically lack the enzyme have also been employed. Humans possessing mutations in the gene encoding aromatase, CYP19, have also provided critical insight into how aromatase affects brain function in a possible sex-dependent manner. A better understanding of how AIs, used to treat breast cancer and other clinical conditions, may detrimentally affect neurobehavioral responses will likely promote development of future therapies to combat these effects. Herein, we will provide a critical review of the current knowledge of sex differences in aromatase regulation of various neurobehavioral functions. Although many species have been used to better understand the functions of aromatase, this review focuses on rodent models and humans. Critical gaps in our present understanding of this area will be considered, and important future research directions will be discussed.
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Affiliation(s)
- Dusti A Shay
- Nutrition and Exercise Physiology, University of Missouri Columbia, MO, United States
| | | | - Cheryl S Rosenfeld
- Bond Life Sciences Center, University of Missouri Columbia, MO, United States.,Thompson Center for Autism and Neurobehavioral Disorders, University of Missouri Columbia, MO, United States.,Department of Biomedical Sciences, University of Missouri Columbia, MO, United States
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Brocca ME, Garcia-Segura LM. Non-reproductive Functions of Aromatase in the Central Nervous System Under Physiological and Pathological Conditions. Cell Mol Neurobiol 2018; 39:473-481. [PMID: 30084008 DOI: 10.1007/s10571-018-0607-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 07/25/2018] [Indexed: 02/07/2023]
Abstract
The modulation of brain function and behavior by steroid hormones was classically associated with their secretion by peripheral endocrine glands. The discovery that the brain expresses the enzyme aromatase, which produces estradiol from testosterone, expanded this traditional concept. One of the best-studied roles of brain estradiol synthesis is the control of reproductive behavior. In addition, there is increasing evidence that estradiol from neural origin is also involved in a variety of non-reproductive functions. These include the regulation of neurogenesis, neuronal development, synaptic transmission, and plasticity in brain regions not directly related with the control of reproduction. Central aromatase is also involved in the modulation of cognition, mood, and non-reproductive behaviors. Furthermore, under pathological conditions aromatase is upregulated in the central nervous system. This upregulation represents a neuroprotective and likely also a reparative response by increasing local estradiol levels in order to maintain the homeostasis of the neural tissue. In this paper, we review the non-reproductive functions of neural aromatase and neural-derived estradiol under physiological and pathological conditions. We also consider the existence of sex differences in the role of the enzyme in both contexts.
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Affiliation(s)
- Maria Elvira Brocca
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain.
| | - Luis Miguel Garcia-Segura
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
- Centro de Investigación Biomédica en Red Fragilidad y Envejecimiento Saludable (CIBERFES), Instituto de Salud Carlos III, Madrid, Spain
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