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Culig L, Chu X, Bohr VA. Neurogenesis in aging and age-related neurodegenerative diseases. Ageing Res Rev 2022; 78:101636. [PMID: 35490966 PMCID: PMC9168971 DOI: 10.1016/j.arr.2022.101636] [Citation(s) in RCA: 39] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 04/14/2022] [Accepted: 04/25/2022] [Indexed: 12/11/2022]
Abstract
Adult neurogenesis, the process by which neurons are generated in certain areas of the adult brain, declines in an age-dependent manner and is one potential target for extending cognitive healthspan. Aging is a major risk factor for neurodegenerative diseases and, as lifespans are increasing, these health challenges are becoming more prevalent. An age-associated loss in neural stem cell number and/or activity could cause this decline in brain function, so interventions that reverse aging in stem cells might increase the human cognitive healthspan. In this review, we describe the involvement of adult neurogenesis in neurodegenerative diseases and address the molecular mechanistic aspects of neurogenesis that involve some of the key aggregation-prone proteins in the brain (i.e., tau, Aβ, α-synuclein, …). We summarize the research pertaining to interventions that increase neurogenesis and regulate known targets in aging research, such as mTOR and sirtuins. Lastly, we share our outlook on restoring the levels of neurogenesis to physiological levels in elderly individuals and those with neurodegeneration. We suggest that modulating neurogenesis represents a potential target for interventions that could help in the fight against neurodegeneration and cognitive decline.
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Affiliation(s)
- Luka Culig
- Section on DNA Repair, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Xixia Chu
- Section on DNA Repair, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Vilhelm A Bohr
- Section on DNA Repair, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA.
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2
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Leschik J, Lutz B, Gentile A. Stress-Related Dysfunction of Adult Hippocampal Neurogenesis-An Attempt for Understanding Resilience? Int J Mol Sci 2021; 22:7339. [PMID: 34298958 PMCID: PMC8305135 DOI: 10.3390/ijms22147339] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 07/02/2021] [Accepted: 07/05/2021] [Indexed: 12/16/2022] Open
Abstract
Newborn neurons in the adult hippocampus are regulated by many intrinsic and extrinsic cues. It is well accepted that elevated glucocorticoid levels lead to downregulation of adult neurogenesis, which this review discusses as one reason why psychiatric diseases, such as major depression, develop after long-term stress exposure. In reverse, adult neurogenesis has been suggested to protect against stress-induced major depression, and hence, could serve as a resilience mechanism. In this review, we will summarize current knowledge about the functional relation of adult neurogenesis and stress in health and disease. A special focus will lie on the mechanisms underlying the cascades of events from prolonged high glucocorticoid concentrations to reduced numbers of newborn neurons. In addition to neurotransmitter and neurotrophic factor dysregulation, these mechanisms include immunomodulatory pathways, as well as microbiota changes influencing the gut-brain axis. Finally, we discuss recent findings delineating the role of adult neurogenesis in stress resilience.
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Affiliation(s)
- Julia Leschik
- Institute of Physiological Chemistry, University Medical Center of the Johannes Gutenberg University Mainz, 55128 Mainz, Germany;
| | - Beat Lutz
- Institute of Physiological Chemistry, University Medical Center of the Johannes Gutenberg University Mainz, 55128 Mainz, Germany;
- Leibniz Institute for Resilience Research (LIR), 55122 Mainz, Germany
| | - Antonietta Gentile
- Synaptic Immunopathology Lab, IRCCS San Raffaele Pisana, 00166 Rome, Italy;
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3
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Brennan GP, Garcia-Curran MM, Patterson KP, Luo R, Baram TZ. Multiple Disruptions of Glial-Neuronal Networks in Epileptogenesis That Follows Prolonged Febrile Seizures. Front Neurol 2021; 12:615802. [PMID: 33679583 PMCID: PMC7930821 DOI: 10.3389/fneur.2021.615802] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 01/25/2021] [Indexed: 12/26/2022] Open
Abstract
Background and Rationale: Bi-directional neuronal-glial communication is a critical mediator of normal brain function and is disrupted in the epileptic brain. The potential role of aberrant microglia and astrocyte function during epileptogenesis is important because the mediators involved provide tangible targets for intervention and prevention of epilepsy. Glial activation is intrinsically involved in the generation of childhood febrile seizures (FS), and prolonged FS (febrile status epilepticus, FSE) antecede a proportion of adult temporal lobe epilepsy (TLE). Because TLE is often refractory to treatment and accompanied by significant memory and emotional difficulties, we probed the role of disruptions of glial-neuronal networks in the epileptogenesis that follows experimental FSE (eFSE). Methods: We performed a multi-pronged examination of neuronal-glia communication and the resulting activation of molecular signaling cascades in these cell types following eFSE in immature mice and rats. Specifically, we examined pathways involving cytokines, microRNAs, high mobility group B-1 (HMGB1) and the prostaglandin E2 signaling. We aimed to block epileptogenesis using network-specific interventions as well as via a global anti-inflammatory approach using dexamethasone. Results: (A) eFSE elicited a strong inflammatory response with rapid and sustained upregulation of pro-inflammatory cytokines. (B) Within minutes of the end of the eFSE, HMGB1 translocated from neuronal nuclei to dendrites, en route to the extracellular space and glial Toll-like receptors. Administration of an HMGB1 blocker to eFSE rat pups did not decrease expression of downstream inflammatory cascades and led to unacceptable side effects. (C) Prolonged seizure-like activity caused overall microRNA-124 (miR-124) levels to plunge in hippocampus and release of this microRNA from neurons via extra-cellular vesicles. (D) Within hours of eFSE, structural astrocyte and microglia activation was associated not only with cytokine production, but also with activation of the PGE2 cascade. However, administration of TG6-10-1, a blocker of the PGE2 receptor EP2 had little effect on spike-series provoked by eFSE. (E) In contrast to the failure of selective interventions, a 3-day treatment of eFSE–experiencing rat pups with the broad anti-inflammatory drug dexamethasone attenuated eFSE-provoked pro-epileptogenic EEG changes. Conclusions: eFSE, a provoker of TLE-like epilepsy in rodents leads to multiple and rapid disruptions of interconnected glial-neuronal networks, with a likely important role in epileptogenesis. The intricate, cell-specific and homeostatic interplays among these networks constitute a serious challenge to effective selective interventions that aim to prevent epilepsy. In contrast, a broad suppression of glial-neuronal dysfunction holds promise for mitigating FSE-induced hyperexcitability and epileptogenesis in experimental models and in humans.
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Affiliation(s)
- Gary P Brennan
- Departments of Anatomy/Neurobiology, Pediatrics, and Neurology, University of California, Irvine, Irvine, CA, United States.,School of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland.,FutureNeuro Research Centre, Royal College of Surgeons Ireland, Dublin, Ireland
| | - Megan M Garcia-Curran
- Departments of Anatomy/Neurobiology, Pediatrics, and Neurology, University of California, Irvine, Irvine, CA, United States
| | - Katelin P Patterson
- Departments of Anatomy/Neurobiology, Pediatrics, and Neurology, University of California, Irvine, Irvine, CA, United States
| | - Renhao Luo
- Departments of Anatomy/Neurobiology, Pediatrics, and Neurology, University of California, Irvine, Irvine, CA, United States
| | - Tallie Z Baram
- Departments of Anatomy/Neurobiology, Pediatrics, and Neurology, University of California, Irvine, Irvine, CA, United States
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4
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Schouten M, Bielefeld P, Garcia-Corzo L, Passchier EMJ, Gradari S, Jungenitz T, Pons-Espinal M, Gebara E, Martín-Suárez S, Lucassen PJ, De Vries HE, Trejo JL, Schwarzacher SW, De Pietri Tonelli D, Toni N, Mira H, Encinas JM, Fitzsimons CP. Circadian glucocorticoid oscillations preserve a population of adult hippocampal neural stem cells in the aging brain. Mol Psychiatry 2020; 25:1382-1405. [PMID: 31222184 PMCID: PMC7303016 DOI: 10.1038/s41380-019-0440-2] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Revised: 04/09/2019] [Accepted: 04/29/2019] [Indexed: 12/17/2022]
Abstract
A decrease in adult hippocampal neurogenesis has been linked to age-related cognitive impairment. However, the mechanisms involved in this age-related reduction remain elusive. Glucocorticoid hormones (GC) are important regulators of neural stem/precursor cells (NSPC) proliferation. GC are released from the adrenal glands in ultradian secretory pulses that generate characteristic circadian oscillations. Here, we investigated the hypothesis that GC oscillations prevent NSPC activation and preserve a quiescent NSPC pool in the aging hippocampus. We found that hippocampal NSPC populations lacking expression of the glucocorticoid receptor (GR) decayed exponentially with age, while GR-positive populations decayed linearly and predominated in the hippocampus from middle age onwards. Importantly, GC oscillations controlled NSPC activation and GR knockdown reactivated NSPC proliferation in aged mice. When modeled in primary hippocampal NSPC cultures, GC oscillations control cell cycle progression and induce specific genome-wide DNA methylation profiles. GC oscillations induced lasting changes in the methylation state of a group of gene promoters associated with cell cycle regulation and the canonical Wnt signaling pathway. Finally, in a mouse model of accelerated aging, we show that disruption of GC oscillations induces lasting changes in dendritic complexity, spine numbers and morphology of newborn granule neurons. Together, these results indicate that GC oscillations preserve a population of GR-expressing NSPC during aging, preventing their activation possibly by epigenetic programming through methylation of specific gene promoters. Our observations suggest a novel mechanism mediated by GC that controls NSPC proliferation and preserves a dormant NSPC pool, possibly contributing to a neuroplasticity reserve in the aging brain.
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Affiliation(s)
- M Schouten
- Neuroscience Collaboration, Swammerdam Institute for Life Sciences, Faculty of Sciences, Amsterdam Neuroscience, University of Amsterdam, Amsterdam, The Netherlands
- Department of Molecular Cell Biology and Immunology, VU University Medical Center, Amsterdam Neuroscience, Amsterdam, The Netherlands
| | - P Bielefeld
- Neuroscience Collaboration, Swammerdam Institute for Life Sciences, Faculty of Sciences, Amsterdam Neuroscience, University of Amsterdam, Amsterdam, The Netherlands
| | - L Garcia-Corzo
- Biomedicine Institute of Valencia (IBV), Consejo Superior de Investigaciones Científicas (CSIC), Valencia, Spain
| | - E M J Passchier
- Neuroscience Collaboration, Swammerdam Institute for Life Sciences, Faculty of Sciences, Amsterdam Neuroscience, University of Amsterdam, Amsterdam, The Netherlands
| | - S Gradari
- Cajal Institute, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
| | - T Jungenitz
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe-University Frankfurt, Frankfurt am Main, Germany
| | - M Pons-Espinal
- Neurobiology of miRNA Lab, Neuroscience and Brain Technologies Department, Istituto Italiano di Tecnologia, Genoa, Italy
| | - E Gebara
- Center for Psychiatric Neuroscience, Department of Psychiatry, Lausanne University Hospital (CHUV), Lausanne, Switzerland
| | | | - P J Lucassen
- Neuroscience Collaboration, Swammerdam Institute for Life Sciences, Faculty of Sciences, Amsterdam Neuroscience, University of Amsterdam, Amsterdam, The Netherlands
| | - H E De Vries
- Department of Molecular Cell Biology and Immunology, VU University Medical Center, Amsterdam Neuroscience, Amsterdam, The Netherlands
| | - J L Trejo
- Cajal Institute, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
| | - S W Schwarzacher
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe-University Frankfurt, Frankfurt am Main, Germany
| | - D De Pietri Tonelli
- Neurobiology of miRNA Lab, Neuroscience and Brain Technologies Department, Istituto Italiano di Tecnologia, Genoa, Italy
| | - N Toni
- Center for Psychiatric Neuroscience, Department of Psychiatry, Lausanne University Hospital (CHUV), Lausanne, Switzerland
| | - H Mira
- Biomedicine Institute of Valencia (IBV), Consejo Superior de Investigaciones Científicas (CSIC), Valencia, Spain
| | - J M Encinas
- Achucarro Basque Center for Neuroscience, Leioa, Spain
- Ikerbasque, The Basque Foundation for Science, Bilbao, Spain
- University of the Basque Country (UPV/EHU), Leioa, Spain
| | - C P Fitzsimons
- Neuroscience Collaboration, Swammerdam Institute for Life Sciences, Faculty of Sciences, Amsterdam Neuroscience, University of Amsterdam, Amsterdam, The Netherlands.
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5
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Lee TK, Kim H, Song M, Lee JC, Park JH, Ahn JH, Yang GE, Kim H, Ohk TG, Shin MC, Cho JH, Won MH. Time-course pattern of neuronal loss and gliosis in gerbil hippocampi following mild, severe, or lethal transient global cerebral ischemia. Neural Regen Res 2019; 14:1394-1403. [PMID: 30964065 PMCID: PMC6524495 DOI: 10.4103/1673-5374.253524] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Transient ischemia in the whole brain leads to neuronal loss/death in vulnerable brain regions. The striatum, neocortex and hippocampus selectively loose specific neurons after transient ischemia. Just 5 minutes of transient ischemia can cause pyramidal neuronal death in the hippocampal cornu ammonis (CA) 1 field at 4 days after transient ischemia. In this study, we investigated the effects of 5-minute (mild), 15-minute (severe), and 20-minute (lethal) transient ischemia by bilateral common carotid artery occlusion (BCCAO) on behavioral change and neuronal death and gliosis (astrocytosis and microgliosis) in gerbil hippocampal subregions (CA1–3 region and dentate gyrus). We performed spontaneous motor activity test to evaluate gerbil locomotor activity, cresyl violet staining to detect cellular distribution, neuronal nuclei immunohistochemistry to detect neuronal distribution, and Fluoro-Jade B histofluorescence to evaluate neuronal death. We also conducted immunohistochemical staining for glial fibrillary acidic protein and ionized calcium-binding adapter molecule 1 (Iba1) to evaluate astrocytosis and microgliosis, respectively. Animals subjected to 20-minute BCCAO died in at least 2 days. BCCAO for 15 minutes led to pyramidal cell death in hippocampal CA1–3 region 2 days later and granule cell death in hippocampal dentate gyrus 5 days later. Similar results were not found in animals subjected to 5-minute BCCAO. Gliosis was much more rapidly and severely progressed in animals subjected to 15-minute BCCAO than in those subjected to 5-minute BCCAO. Our results indicate that neuronal loss in the hippocampal formation following transient ischemia is significantly different according to regions and severity of transient ischemia. The experimental protocol was approved by Institutional Animal Care and Use Committee (AICUC) of Kangwon National University (approval No. KW-180124-1) on May 22, 2018.
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Affiliation(s)
- Tae-Kyeong Lee
- Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon, Gangwon, Republic of Korea
| | - Hyunjung Kim
- Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon, Gangwon, Republic of Korea
| | - Minah Song
- Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon, Gangwon, Republic of Korea
| | - Jae-Chul Lee
- Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon, Gangwon, Republic of Korea
| | - Joon Ha Park
- Department of Biomedical Science and Research Institute for Bioscience and Biotechnology, Hallym University, Chuncheon, Gangwon, Republic of Korea
| | - Ji Hyeon Ahn
- Department of Biomedical Science and Research Institute for Bioscience and Biotechnology, Hallym University, Chuncheon, Gangwon, Republic of Korea
| | - Go Eun Yang
- Department of Radiology, Kangwon National University Hospital, Chuncheon, Gangwon, Republic of Korea
| | - Hyeyoung Kim
- Department of Anesthesiology and Pain Medicine, Chungju Hospital, Konkuk University School of Medicine, Chungju Chungcheongbuk; Department of Emergency Medicine, School of Medicine, Kangwon National University, Chuncheon, Gangwon, Republic of Korea
| | - Taek Geun Ohk
- Department of Emergency Medicine, School of Medicine, Kangwon National University, Chuncheon, Gangwon, Republic of Korea
| | - Myoung Cheol Shin
- Department of Emergency Medicine, School of Medicine, Kangwon National University, Chuncheon, Gangwon, Republic of Korea
| | - Jun Hwi Cho
- Department of Emergency Medicine, School of Medicine, Kangwon National University, Chuncheon, Gangwon, Republic of Korea
| | - Moo-Ho Won
- Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon, Gangwon, Republic of Korea
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6
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Fitzsimons CP, Herbert J, Schouten M, Meijer OC, Lucassen PJ, Lightman S. Circadian and ultradian glucocorticoid rhythmicity: Implications for the effects of glucocorticoids on neural stem cells and adult hippocampal neurogenesis. Front Neuroendocrinol 2016; 41:44-58. [PMID: 27234350 DOI: 10.1016/j.yfrne.2016.05.001] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Revised: 05/01/2016] [Accepted: 05/03/2016] [Indexed: 01/01/2023]
Abstract
Psychosocial stress, and within the neuroendocrine reaction to stress specifically the glucocorticoid hormones, are well-characterized inhibitors of neural stem/progenitor cell proliferation in the adult hippocampus, resulting in a marked reduction in the production of new neurons in this brain area relevant for learning and memory. However, the mechanisms by which stress, and particularly glucocorticoids, inhibit neural stem/progenitor cell proliferation remain unclear and under debate. Here we review the literature on the topic and discuss the evidence for direct and indirect effects of glucocorticoids on neural stem/progenitor cell proliferation and adult neurogenesis. Further, we discuss the hypothesis that glucocorticoid rhythmicity and oscillations originating from the activity of the hypothalamus-pituitary-adrenal axis, may be crucial for the regulation of neural stem/progenitor cells in the hippocampus, as well as the implications of this hypothesis for pathophysiological conditions in which glucocorticoid oscillations are affected.
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Affiliation(s)
- Carlos P Fitzsimons
- Neuroscience Program, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098XH Amsterdam, The Netherlands.
| | - Joe Herbert
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, United Kingdom
| | - Marijn Schouten
- Neuroscience Program, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098XH Amsterdam, The Netherlands
| | - Onno C Meijer
- Leiden University Medical Centre, Department of Endocrinology, Leiden, The Netherlands
| | - Paul J Lucassen
- Neuroscience Program, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098XH Amsterdam, The Netherlands.
| | - Stafford Lightman
- Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, School of Clinical Sciences, Faculty of Medicine and Dentistry, University of Bristol, United Kingdom
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7
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Hoeijmakers L, Lucassen PJ, Korosi A. The interplay of early-life stress, nutrition, and immune activation programs adult hippocampal structure and function. Front Mol Neurosci 2015; 7:103. [PMID: 25620909 PMCID: PMC4288131 DOI: 10.3389/fnmol.2014.00103] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 12/16/2014] [Indexed: 01/08/2023] Open
Abstract
Early-life adversity increases the vulnerability to develop psychopathologies and cognitive decline later in life. This association is supported by clinical and preclinical studies. Remarkably, experiences of stress during this sensitive period, in the form of abuse or neglect but also early malnutrition or an early immune challenge elicit very similar long-term effects on brain structure and function. During early-life, both exogenous factors like nutrition and maternal care, as well as endogenous modulators, including stress hormones and mediator of immunological activity affect brain development. The interplay of these key elements and their underlying molecular mechanisms are not fully understood. We discuss here the hypothesis that exposure to early-life adversity (specifically stress, under/malnutrition and infection) leads to life-long alterations in hippocampal-related cognitive functions, at least partly via changes in hippocampal neurogenesis. We further discuss how these different key elements of the early-life environment interact and affect one another and suggest that it is a synergistic action of these elements that shapes cognition throughout life. Finally, we consider different intervention studies aiming to prevent these early-life adversity induced consequences. The emerging evidence for the intriguing interplay of stress, nutrition, and immune activity in the early-life programming calls for a more in depth understanding of the interaction of these elements and the underlying mechanisms. This knowledge will help to develop intervention strategies that will converge on a more complete set of changes induced by early-life adversity.
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Affiliation(s)
- Lianne Hoeijmakers
- Center for Neuroscience, Swammerdam Institute for Life Sciences, University of Amsterdam Amsterdam, Netherlands
| | - Paul J Lucassen
- Center for Neuroscience, Swammerdam Institute for Life Sciences, University of Amsterdam Amsterdam, Netherlands
| | - Aniko Korosi
- Center for Neuroscience, Swammerdam Institute for Life Sciences, University of Amsterdam Amsterdam, Netherlands
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8
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Perinatal programming of adult hippocampal structure and function; emerging roles of stress, nutrition and epigenetics. Trends Neurosci 2013; 36:621-31. [PMID: 23998452 DOI: 10.1016/j.tins.2013.08.002] [Citation(s) in RCA: 129] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Revised: 08/05/2013] [Accepted: 08/06/2013] [Indexed: 11/22/2022]
Abstract
Early-life stress lastingly affects adult cognition and increases vulnerability to psychopathology, but the underlying mechanisms remain elusive. In this Opinion article, we propose that early nutritional input together with stress hormones and sensory stimuli from the mother during the perinatal period act synergistically to program the adult brain, possibly via epigenetic mechanisms. We hypothesize that stress during gestation or lactation affects the intake of macro- and micronutrients, including dietary methyl donors, and/or impairs the dam's metabolism, thereby altering nutrient composition and intake by the offspring. In turn, this may persistently modulate gene expression via epigenetic programming, thus altering hippocampal structure and cognition. Understanding how the combination of stress, nutrition, and epigenetics shapes the adult brain is essential for effective therapies.
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9
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Time-course of hippocampal granule cell degeneration and changes in adult neurogenesis after adrenalectomy in rats. Neuroscience 2011; 190:166-76. [DOI: 10.1016/j.neuroscience.2011.06.023] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2010] [Revised: 05/27/2011] [Accepted: 06/07/2011] [Indexed: 12/30/2022]
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10
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Marrone DF, Ramirez-Amaya V, Barnes CA. Neurons generated in senescence maintain capacity for functional integration. Hippocampus 2011; 22:1134-42. [PMID: 21695743 DOI: 10.1002/hipo.20959] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/31/2011] [Indexed: 12/19/2022]
Abstract
Adult-born neurons in the dentate gyrus (DG) can survive for long periods, are capable of integrating into neuronal networks, and are important for hippocampus-dependent learning. Neurogenesis is dramatically reduced during senescence, and it remains unknown whether those few neurons that are produced remain capable of network integration. The expression of Arc, a protein coupled to neuronal activity, was used to measure activity among granule cells that were labeled with BrdU 4 months earlier in young (9 months) and aged (25 months) Fischer344 rats. The results indicate that while fewer cells are generated in the senescent DG, those that survive are (a) more likely to respond to spatial processing by expressing Arc relative to the remainder of the granule cell population and (b) equally responsive to spatial exploration as granule cells of the same age from young animals. These findings provide compelling evidence that newborn granule cells in the aged DG retain the capacity for participation in functional hippocampal networks.
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Affiliation(s)
- Diano F Marrone
- Department of Psychology, Wilfrid Laurier University, Waterloo, Ontario, Canada
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11
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Brooks-Kayal A. Molecular mechanisms of cognitive and behavioral comorbidities of epilepsy in children. Epilepsia 2011; 52 Suppl 1:13-20. [PMID: 21214535 DOI: 10.1111/j.1528-1167.2010.02906.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Intellectual and developmental disabilities (IDDs) such as autistic spectrum disorders (ASDs) and epilepsies are heterogeneous disorders that have diverse etiologies and pathophysiologies. The high rate of co-occurrence of these disorders, however, suggests potentially shared underlying mechanisms. A number of well-known genetic disorders share epilepsy, intellectual disability, and autism as prominent phenotypic features, including tuberous sclerosis complex, Rett syndrome, and fragile X syndrome. In addition, mutations of several genes involved in neurodevelopment, including ARX, DCX, neuroligins, and neuropilin 2 have been identified in children with epilepsy, IDDs, ASDs, or a combination of thereof. Finally, in animal models, early life seizures can result in cellular and molecular changes that could contribute to learning and behavioral disabilities. Increased understanding of the common genetic, molecular, and cellular mechanisms of IDDs, ASDs, and epilepsy may provide insight into their underlying pathophysiology and elucidate new therapeutic approaches for these conditions.
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Affiliation(s)
- Amy Brooks-Kayal
- Department of Pediatrics, University of Colorado Denver School of Medicine, Aurora, USA.
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12
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Brooks-Kayal A. Epilepsy and autism spectrum disorders: are there common developmental mechanisms? Brain Dev 2010; 32:731-8. [PMID: 20570072 DOI: 10.1016/j.braindev.2010.04.010] [Citation(s) in RCA: 104] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2010] [Accepted: 04/27/2010] [Indexed: 12/12/2022]
Abstract
Autistic spectrum disorders (ASD) and epilepsies are heterogeneous disorders that have diverse etiologies and pathophysiologies. The high rate of co-occurrence of these disorders suggest potentially shared underlying mechanisms. A number of well-known genetic disorders share epilepsy and autism as prominent phenotypic features, including tuberous sclerosis, Rett syndrome, and fragile X. In addition, mutations of several genes involved in neurodevelopment, including ARX, DCX, neuroligins and neuropilin2 have been identified in children with epilepsy, ASD or often both. Finally, in animal models, early-life seizures can result in cellular and molecular changes that could contribute to learning and behavioral disabilities as seen in ASD. Increased understanding of the common genetic, molecular and cellular mechanisms of ASD and epilepsy may provide insight into their underlying pathophysiology and elucidate new therapeutic approaches of both conditions.
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Affiliation(s)
- Amy Brooks-Kayal
- Department of Pediatrics, University of Colorado Denver School of Medicine, The Children's Hospital Denver, 13123 E 16th Avenue, B155, Aurora, CO 80045, United States.
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13
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Epp JR, Barker JM, Galea LAM. Running wild: Neurogenesis in the hippocampus across the lifespan in wild and laboratory-bred Norway rats. Hippocampus 2009; 19:1040-9. [DOI: 10.1002/hipo.20546] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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14
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McKernan DP, Dinan TG, Cryan JF. “Killing the Blues”: A role for cellular suicide (apoptosis) in depression and the antidepressant response? Prog Neurobiol 2009; 88:246-63. [DOI: 10.1016/j.pneurobio.2009.04.006] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2008] [Revised: 03/19/2009] [Accepted: 04/29/2009] [Indexed: 01/15/2023]
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15
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Wolf SA, Steiner B, Wengner A, Lipp M, Kammertoens T, Kempermann G. Adaptive peripheral immune response increases proliferation of neural precursor cells in the adult hippocampus. FASEB J 2009; 23:3121-8. [PMID: 19433626 DOI: 10.1096/fj.08-113944] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
To understand the link between peripheral immune activation and neuronal precursor biology, we investigated the effect of T-cell activation on adult hippocampal neurogenesis in female C57Bl/6 mice. A peripheral adaptive immune response triggered by adjuvant-induced rheumatoid arthritis (2 microg/microl methylated BSA) or staphylococcus enterotoxin B (EC(50) of 0.25 microg/ml per 20 g body weight) was associated with a transient increase in hippocampal precursor cell proliferation and neurogenesis as assessed by immunohistochemistry and confocal microscopy. Both treatments were paralleled by an increase in corticosterone levels in the hippocampus 1- to 2-fold over the physiological amount measured by quantitative radioimmunoassay. In contrast, intraperitoneal administration of the innate immune response activator lipopolysaccaride (EC(50) of 0.5 microg/ml per 20 g body weight) led to a chronic 5-fold increase of hippocampal glucocorticoid levels and a decrease of adult neurogenesis. In vitro exposure of murine neuronal progenitor cells to corticosterone triggered either cell death at high (1.5 nM) or proliferation at low (0.25 nM) concentrations. This effect could be blocked using a viral vector system expressing a transdomain of the glucocorticoid receptor. We suggest an evolutionary relevant communication route for the brain to respond to environmental stressors like inflammation mediated by glucocorticoid levels in the hippocampus.
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Affiliation(s)
- Susanne A Wolf
- Neuronal Stem Cells Research Group, Max Delbrück Centre for Molecular Medicine, Berlin-Buch, Germany
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16
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Lin TC, Huang LT, Huang YN, Chen GS, Wang JY. Neonatal status epilepticus alters prefrontal-striatal circuitry and enhances methamphetamine-induced behavioral sensitization in adolescence. Epilepsy Behav 2009; 14:316-23. [PMID: 19126440 DOI: 10.1016/j.yebeh.2008.12.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2008] [Revised: 11/30/2008] [Accepted: 12/13/2008] [Indexed: 11/24/2022]
Abstract
Neonatal seizures may alter the developing neurocircuitry and cause behavioral abnormalities in adulthood. We found that rats previously subjected to lithium-pilocarpine (LiPC)-induced neonatal status epilepticus (NeoSE) exhibited enhanced behavioral sensitization to methamphetamine (MA) in adolescence. Neurochemically, dopamine (DA) and metabolites were markedly decreased in prefrontal cortex (PFC) and insignificantly changed in striatum by NeoSE, but were increased in both PFC and striatum by NeoSE+MA. Glutamate levels were increased in both PFC and striatum in the NeoSE+MA group. DA turnover, an index of utilization and activity, was increased by NeoSE but reversed by MA in PFC. Gene expression of the regulator of G-protein signaling 4 (RGS4) was downregulated in PFC and striatum by NeoSE and further suppressed by MA. These findings suggest NeoSE affects both dopaminergic and glutamatergic systems in the prefrontal-striatal circuitry that manifests as enhanced behavioral sensitization to MA in adolescence.
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Affiliation(s)
- Tzu-Chao Lin
- Graduate Institute of Medical Sciences, National Defense Medical Center, Taipei, Taiwan, ROC
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17
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Kim K, Son TG, Park HR, Kim SJ, Kim HS, Kim HS, Kim TS, Jung KK, Han SY, Lee J. Potencies of bisphenol A on the neuronal differentiation and hippocampal neurogenesis. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2009; 72:1343-51. [PMID: 20077206 DOI: 10.1080/15287390903212501] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Endocrine-disrupting chemicals (EDC) produce adverse effects on reproductive and immune function or neurological behavior, and may also induce cancer. The environmental EDC bisphenol A (BPA) is widely used in the manufacture of plastics and epoxy resins. BPA affects reproductive organ growth and development, but the potential adverse effects of BPA on neuronal development are not fully understood. Here, BPA concentration-dependently decreased proliferation of murine-derived multipotent neural progenitor cells (NPC), and high concentrations produced cytotoxicity. In contrast, low concentrations of BPA, which possess estrogenic activity, stimulated NPC differentiation into a neuronal phenotype. BPA treatment did not affect neonatal brain development in F1 mice. However, BPA treatment (20 mg/kg) accelerated formation of the dentate gyrus in postnatal day 1 mice. Prenatal and postnatal BPA treatment did not affect adult hippocampal neurogenesis in the dentate gyrus in 8-wk-old mice. Data indicate that BPA stimulates neuronal differentiation and might disrupt neonatal brain development.
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Affiliation(s)
- Keunho Kim
- Department of Pharmacy, College of Pharmacy and Longevity Life Science and Technology Institutes, Pusan National University, Geumjeong-gu, Busan, Korea
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18
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Yi SS, Hwang IK, Chun MS, Kim YN, Kim IY, Lee IS, Seong JK, Yoon YS. Glucocorticoid receptor changes associate with age in the paraventricular nucleus of type II diabetic rat model. Neurochem Res 2008; 34:851-8. [PMID: 18758953 DOI: 10.1007/s11064-008-9836-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2008] [Accepted: 08/12/2008] [Indexed: 12/25/2022]
Abstract
Diabetes is a metabolic disorder that is associated with the dysregulation of a number of systems within the body. In the present study, we investigated glucocorticoid receptor (GR) immunoreactivity and its protein levels in the paraventricular nuclei of 4-, 12-, 20- and 30-week-old Zucker diabetic fatty (fa/fa, ZDF) and in Zucker lean control (fa/+ or +/+, ZLC) rats, because the progressive induction of diabetes is detectable in this model after 7 weeks of age and chronic diabetic conditions are maintained after 12 weeks of age. GR immunoreactivity was detected in parvocellular paraventricular nuclei and this and GR protein levels were exponentially increased according to the ages. In particular, GR immunoreactivities and protein levels were markedly more increased in 30-week-old ZDF rats than in age-matched ZLC group and in younger ZDF group. The present study suggests that GR immunoreactivity and its protein level is associated with a degenerative phenotype in the hypothalamus of from 12-weeks old in the ZDF rat type II diabetes model.
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Affiliation(s)
- Sun Shin Yi
- Department of Anatomy and Cell Biology, College of Veterinary Medicine and BK21 Program for Veterinary Science, Seoul National University, Seoul, South Korea
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19
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Drapeau E, Nora Abrous D. Stem cell review series: role of neurogenesis in age-related memory disorders. Aging Cell 2008; 7:569-89. [PMID: 18221417 PMCID: PMC2990912 DOI: 10.1111/j.1474-9726.2008.00369.x] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/28/2007] [Indexed: 02/06/2023] Open
Abstract
Neuroplasticity is characterized by growth and branching of dendrites, remodeling of synaptic contacts, and neurogenesis, thus allowing the brain to adapt to changes over time. It is maintained in adulthood but strongly repressed during aging. An age-related decline in neurogenesis is particularly pronounced in the two adult neurogenic areas, the subventricular zone and the dentate gyrus. This age-related decline seems to be attributable mainly to limited proliferation, associated with an age-dependent increase in quiescence and/or a lengthening of the cell cycle, and is closely dependent on environmental changes. Indeed, when triggered by appropriate signals, neurogenesis can be reactivated in senescent brains, thus confirming the idea that the age-related decrease in new neuron production is not an irreversible, cell-intrinsic process. The coevolution of neurogenesis and age-related memory deficits--especially regarding spatial memory--during senescence supports the idea that new neurons in the adult brain participate in memory processing, and that a reduction in the ability to generate new neurons contributes to the appearance of memory deficits with advanced age. Furthermore, the age-related changes in hippocampal plasticity and function are under environmental influences that can favor successful or pathological aging. A better understanding of the mechanisms that regulate neurogenesis is necessary to develop new therapeutic tools to cure or prevent the development of memory disorders that may appear during the course of aging in some individuals.
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Affiliation(s)
- Elodie Drapeau
- Doetsch's Laboratory, Columbia University, Department of PathologyP&S 14-511, 630 W 168th Street, New York, NY 10032, USA
| | - Djoher Nora Abrous
- INSERM U862, Bordeaux Neuroscience Research Center, University of Bordeaux 2Bordeaux Cedex 33077, France
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20
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YANAI SHUICHI, OKAICHI HIROSHIGE, SUGIOKA KOZO. Dietary restriction inhibits spatial learning ability and hippocampal cell proliferation in rats. JAPANESE PSYCHOLOGICAL RESEARCH 2008. [DOI: 10.1111/j.1468-5884.2007.00360.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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21
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Shi XY, Wang JW, Lei GF, Sun RP. Morphological and behavioral consequences of recurrent seizures in neonatal rats are associated with glucocorticoid levels. Neurosci Bull 2007; 23:83-91. [PMID: 17592530 PMCID: PMC5550591 DOI: 10.1007/s12264-007-0012-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
OBJECTIVE It is well documented that epilepsy can increase neurogenesis in certain brain regions and cause behavioral alternations in patients and different epileptic animal models. A series of experimental studies have demonstrated that neurogenesis is regulated by various factors including glucocorticoid (CORT), which can reduce neurogenesis. Most of studies in animal have been focused on adulthood stage, while the effect of recurrent seizures to immature brain in neonatal period has not been well established. This study was designed to investigate how the recurrent seizures occurred in the neonatal period affected the immature brain and how CORT regulated neurogenesis in immature animals. METHODS Neonatal rats were subjected to 3 pilocarpine-induced seizures from postnatal day 1 to day 7. Then neurogenesis at different postnatal ages (i.e. P8, P12, P22, P50) was observed. Behavioral performance was tested when the rats were mature (P40), and plasma CORT levels following recurrent seizures were simultaneously monitored. RESULTS Rats with neonatal seizures had a significant reduction in the number of Bromodeoxyuridine (BrdU) labeled cells in the dentate gyrus compared with the control groups when the animals were euthanized on P8 or P12 (P<0.05); whereas there was no difference between the two groups on P22. Until P50, rats with neonatal seizures had increased number of BrdU-labeled cells compared with the control group (P<0.05). In Morris water maze task, pilocarpine-treated rats were significantly slower than the control rats at the first and second day, and there were no differences at other days. In probe trial, there was no significant difference in time spent in the goal quadrant between the two groups. Endocrine studies showed a correlation between the number of BrdU positive cells and the CORT level. Sustained increase in circulating CORT levels was observed following neonatal seizures on P8 and P12. CONCLUSION Neonatal recurrent seizures can biphasely modulate neurogenesis over different time windows with a down-regulation at early time and up-regulation afterwards, cause persistent deficits in cognitive functions of adults, and increase the circulating CORT levels. CORT levels are related with the morphological and behavioral consequences of recurrent seizures.
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Affiliation(s)
- Xiu-Yu Shi
- Department of Pediatrics, Qilu Hospital, Shandong University, Jinan, 250012 China
| | - Ji-Wen Wang
- Department of Pediatrics, Qilu Hospital, Shandong University, Jinan, 250012 China
| | - Ge-Fei Lei
- Department of Pediatrics, Qilu Hospital, Shandong University, Jinan, 250012 China
| | - Ruo-Peng Sun
- Department of Pediatrics, Qilu Hospital, Shandong University, Jinan, 250012 China
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22
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Joëls M, Karst H, Krugers HJ, Lucassen PJ. Chronic stress: implications for neuronal morphology, function and neurogenesis. Front Neuroendocrinol 2007; 28:72-96. [PMID: 17544065 DOI: 10.1016/j.yfrne.2007.04.001] [Citation(s) in RCA: 277] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2007] [Revised: 04/12/2007] [Accepted: 04/20/2007] [Indexed: 12/19/2022]
Abstract
In normal life, organisms are repeatedly exposed to brief periods of stress, most of which can be controlled and adequately dealt with. The presently available data indicate that such brief periods of stress have little influence on the shape of neurons or adult neurogenesis, yet change the physiological function of cells in two time-domains. Shortly after stress excitability in limbic areas is rapidly enhanced, but also in brainstem neurons which produce catecholamines; collectively, during this phase the stress hormones promote focused attention, alertness, vigilance and the initial steps in encoding of information linked to the event. Later on, when the hormone concentrations are back to their pre-stress level, gene-mediated actions by corticosteroids reverse and normalize the enhanced excitability, an adaptive response meant to curtail defense reactions against stressors and to enable further storage of relevant information. When stress is experienced repetitively in an uncontrollable and unpredictable manner, a cascade of processes in brain is started which eventually leads to profound, region-specific alterations in dendrite and spine morphology, to suppression of adult neurogenesis and to inappropriate functional responses to a brief stress exposure including a sensitized activation phase and inadequate normalization of brain activity. Although various compounds can effectively prevent these cellular changes by chronic stress, the exact mechanism by which the effects are accomplished is poorly understood. One of the challenges for future research is to link the cellular changes seen in animal models for chronic stress to behavioral effects and to understand the risks they can impose on humans for the precipitation of stress-related disorders.
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Affiliation(s)
- Marian Joëls
- SILS-CNS, University of Amsterdam, Kruislaan 320, 1098 SM Amsterdam, The Netherlands.
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23
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Marsh ED, Brooks-Kayal AR, Porter BE. Seizures and Antiepileptic Drugs: Does Exposure Alter Normal Brain Development? Epilepsia 2006; 47:1999-2010. [PMID: 17201696 DOI: 10.1111/j.1528-1167.2006.00894.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Seizures and antiepileptic drugs (AEDs) affect brain development and have long-term neurological consequences. The specific molecular and cellular changes, the precise timing of their influence during brain development, and the full extent of the long-term consequences of seizures and AEDs exposure have not been established. This review critically assesses both the basic and clinical science literature on the effects of seizures and AEDs on the developing brain and finds that evidence exists to support the hypothesis that both seizures and antiepileptic drugs influence a variety of biological process, at specific times during development, which alter long-term cognition and epilepsy susceptibility. More research, both clinical and experimental, is needed before changes in current clinical practice, based on the scientific data, can be recommended.
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Affiliation(s)
- Eric D Marsh
- Division of Child Neurology and Pediatric Regional Epilepsy Program, Children's Hospital of Philadelphia, and Department of Neurology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
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24
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Lagace DC, Yee JK, Bolaños CA, Eisch AJ. Juvenile administration of methylphenidate attenuates adult hippocampal neurogenesis. Biol Psychiatry 2006; 60:1121-30. [PMID: 16893528 DOI: 10.1016/j.biopsych.2006.04.009] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2006] [Revised: 03/31/2006] [Accepted: 04/04/2006] [Indexed: 12/31/2022]
Abstract
BACKGROUND The neural consequences of early-life exposure to methylphenidate (MPH; Ritalin) are of great interest given the widespread, and sometimes inappropriate, use in children. Here we examine the impact of juvenile MPH exposure on adult hippocampal neurogenesis. METHODS Rats received MPH (2.0 mg/kg, intraperitoneal, twice daily) or saline (SAL) during preadolescence (postnatal days 20-35). Hippocampal cell proliferation (Experiment 1), neurogenesis (Experiment 2), and stress-induced changes in cell proliferation (Experiment 3) were assessed at several developmental stages including adulthood. RESULTS Juvenile exposure to MPH did not alter proliferation at any developmental time point relative to control rats; however, exposure to MPH significantly decreased the long-term survival of newborn cells in adult rats, particularly in the temporal hippocampus. Although MPH-treated rats had higher levels of corticosterone after restraint stress, they did not show the expected greater decrease in hippocampal cell proliferation relative to control animals. CONCLUSIONS Early-life exposure to MPH inhibits the survival of adult-generated neurons in the temporal hippocampus and may reduce progenitor sensitivity to corticosterone-induced decreases in proliferation. These findings suggest that decreased adult neurogenesis is an enduring consequence of early-life exposure to MPH and are discussed for their relevance to humans.
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Affiliation(s)
- Diane C Lagace
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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25
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Hattiangady B, Shetty AK. Aging does not alter the number or phenotype of putative stem/progenitor cells in the neurogenic region of the hippocampus. Neurobiol Aging 2006; 29:129-47. [PMID: 17092610 PMCID: PMC3612500 DOI: 10.1016/j.neurobiolaging.2006.09.015] [Citation(s) in RCA: 186] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2006] [Revised: 08/09/2006] [Accepted: 09/13/2006] [Indexed: 12/20/2022]
Abstract
To investigate whether dramatically waned dentate neurogenesis during aging is linked to diminution in neural stem/progenitor cell (NSC) number, we counted cells immunopositive for Sox-2 (a putative marker of NSCs) in the subgranular zone (SGZ) of young, middle-aged and aged F344 rats. The young SGZ comprised approximately 50,000 Sox-2+ cells and this amount did not diminish with aging. Quantity of GFAP+ cells and vimentin+ radial glia also remained stable during aging in this region. Besides, in all age groups, analogous fractions of Sox-2+ cells expressed GFAP (astrocytes/NSCs), NG-2 (oligodendrocyte-progenitors/NSCs), vimentin (radial glia), S-100beta (astrocytes) and doublecortin (new neurons). Nevertheless, analyses of Sox-2+ cells with proliferative markers insinuated an increased quiescence of NSCs with aging. Moreover, the volume of rat-endothelial-cell-antigen-1+ capillaries (vascular-niches) within the SGZ exhibited an age-related decline, resulting in an increased expanse between NSCs and capillaries. Thus, decreased dentate neurogenesis during aging is not attributable to altered number or phenotype of NSCs. Instead, it appears to be an outcome of increased quiescence of NSCs due to changes in NSC milieu.
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Affiliation(s)
- Bharathi Hattiangady
- Department of Surgery (Neurosurgery), Duke University Medical Center, Durham, NC 27710, United States
- Medical Research and Surgery Services, Veterans Affairs Medical Center, Durham, NC 27705, United States
| | - Ashok K. Shetty
- Department of Surgery (Neurosurgery), Duke University Medical Center, Durham, NC 27710, United States
- Medical Research and Surgery Services, Veterans Affairs Medical Center, Durham, NC 27705, United States
- Corresponding author at: Division of Neurosurgery, DUMC Box 3807, Duke University Medical Center, Durham, NC 27710, United States. Tel.: +1 919 286 0411x7096; fax: +1 919 286 4662., (A.K. Shetty)
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26
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Schauwecker PE. Genetic influence on neurogenesis in the dentate gyrus of two strains of adult mice. Brain Res 2006; 1120:83-92. [PMID: 16999941 DOI: 10.1016/j.brainres.2006.08.086] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2006] [Revised: 08/04/2006] [Accepted: 08/22/2006] [Indexed: 10/24/2022]
Abstract
Previous studies have suggested that there is a genetic influence on the regulation of cell proliferation and survival within the hippocampus. However, the links between perturbations in neurogenesis and genomic control remain unclear. Here, we examined the impact of mouse strain on four parameters of the neurogenic program, proliferation, migration, differentiation and survival in the dentate gyrus of the hippocampus as a means of determining whether allelic variation of two independently derived mouse strains, FVB/NJ and C57BL/6J, modulates basal adult murine dentate gyrus neurogenesis. New cells were labeled with the thymidine analogue 5-bromo-2'-deoxyuridine (BrdU) and their identity was determined immunocytochemically with various phenotypic markers. Consistent with previous studies in other strains of mice, we observed a strain-dependent difference in hippocampal proliferation. Hippocampal cell proliferation in FVB/NJ mice was reduced as compared to animals of the C57BL/6J strain. In contrast, the number of surviving cells in C57BL/6J mice was not significantly different from FVB/NJ mice. Regardless of mouse strain, the majority of surviving BrdU-labeled cells migrated into the granule cell layer and was of a neuronal phenotype. However, fewer surviving cells were located within the granule cell layer of FVB/NJ mice as compared to C57BL/6J mice. Overall, regardless of strain, no significant differences in the relative ratio of neurogenesis versus gliagenesis were observed. These results suggest that genetic background primarily influences newborn cell proliferation and migration, but not differentiation or survival.
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Affiliation(s)
- Paula Elyse Schauwecker
- Department of Cell and Neurobiology, University of Southern California, Keck School of Medicine, 1333 San Pablo Street, BMT 403, Los Angeles, CA 90089-9112, USA.
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27
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Buckwalter MS, Yamane M, Coleman BS, Ormerod BK, Chin JT, Palmer T, Wyss-Coray T. Chronically increased transforming growth factor-beta1 strongly inhibits hippocampal neurogenesis in aged mice. THE AMERICAN JOURNAL OF PATHOLOGY 2006; 169:154-64. [PMID: 16816369 PMCID: PMC1698757 DOI: 10.2353/ajpath.2006.051272] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
There is increasing evidence that hippocampal learning correlates strongly with neurogenesis in the adult brain. Increases in neurogenesis after brain injury also correlate with improved outcomes. With aging the capacity to generate new neurons decreases dramatically, both under normal conditions and after injury. How this decrease occurs is not fully understood, but we hypothesized that transforming growth factor (TGF)-beta1, a cell cycle regulator that rapidly increases after injury and with age, might play a role. We found that chronic overproduction of TGF-beta1 from astrocytes almost completely blocked the generation of new neurons in aged transgenic mice. Even young adult TGF-beta1 mice had 60% fewer immature, doublecortin-positive, hippocampal neurons than wild-type littermate controls. Bromodeoxyuridine labeling of dividing cells in 2-month-old TGF-beta1 mice confirmed this decrease in neuro-genesis and revealed a similar decrease in astrogenesis. Treatment of early neural progenitor cells with TGF-beta1 inhibited their proliferation. This strongly suggests that TGF-beta1 directly affects these cells before their differentiation into neurons and astrocytes. Together, these data show that TGF-beta1 is a potent inhibitor of hippocampal neural progenitor cell proliferation in adult mice and suggest that it plays a key role in limiting injury and age-related neurogenesis.
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Affiliation(s)
- Marion S Buckwalter
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, SUMC Rm. 343A, Stanford, CA 94305-5235, USA
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