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Santos VR, Tilelli CQ, Fernandes A, de Castro OW, Del-Vecchio F, Garcia-Cairasco N. Different types of Status Epilepticus may lead to similar hippocampal epileptogenesis processes. IBRO Neurosci Rep 2023; 15:68-76. [PMID: 37457787 PMCID: PMC10338355 DOI: 10.1016/j.ibneur.2023.06.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 06/05/2023] [Accepted: 06/05/2023] [Indexed: 07/18/2023] Open
Abstract
About 1-2% of people worldwide suffer from epilepsy, which is characterized by unpredictable and intermittent seizure occurrence. Despite the fact that the exact origin of temporal lobe epilepsy is frequently unknown, it is frequently linked to an early triggering insult like brain damage, tumors, or Status Epilepticus (SE). We used an experimental approach consisting of electrical stimulation of the amygdaloid complex to induce two behaviorally and structurally distinct SE states: Type I (fully convulsive), with more severe seizure behaviors and more extensive brain damage, and Type II (partial convulsive), with less severe seizure behaviors and brain damage. Our goal was to better understand how the various types of SE impact the hippocampus leading to the development of epilepsy. Despite clear variations between the two behaviors in terms of neurodegeneration, study of neurogenesis revealed a comparable rise in the number of Ki-67 + cells and an increase in Doublecortin (DCX) in both kinds of SE.
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Affiliation(s)
- Victor R. Santos
- Department of Physiology, Ribeirão Preto School of Medicine, University of São Paulo, Ribeirão Preto, SP, Brazil
- Department of Morphology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, MG, Brazil
| | - Cristiane Q. Tilelli
- Department of Physiology, Ribeirão Preto School of Medicine, University of São Paulo, Ribeirão Preto, SP, Brazil
- Campus Centro-Oeste Dona Lindu, Federal University of São João Del Rey, Divinópolis, MG, Brazil
| | - Artur Fernandes
- Department of Physiology, Ribeirão Preto School of Medicine, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Olagide Wagner de Castro
- Department of Physiology, Ribeirão Preto School of Medicine, University of São Paulo, Ribeirão Preto, SP, Brazil
- Department of Pharmacology and Physiology, Universidade Federal de Alagoas, Maceió, AL, Brazil
| | - Flávio Del-Vecchio
- Department of Physiology, Ribeirão Preto School of Medicine, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Norberto Garcia-Cairasco
- Department of Physiology, Ribeirão Preto School of Medicine, University of São Paulo, Ribeirão Preto, SP, Brazil
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2
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Loef D, Tendolkar I, van Eijndhoven PFP, Hoozemans JJM, Oudega ML, Rozemuller AJM, Lucassen PJ, Dols A, Dijkstra AA. Electroconvulsive therapy is associated with increased immunoreactivity of neuroplasticity markers in the hippocampus of depressed patients. Transl Psychiatry 2023; 13:355. [PMID: 37981649 PMCID: PMC10658169 DOI: 10.1038/s41398-023-02658-1] [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: 04/13/2023] [Revised: 10/23/2023] [Accepted: 11/07/2023] [Indexed: 11/21/2023] Open
Abstract
Electroconvulsive therapy (ECT) is an effective therapy for depression, but its cellular effects on the human brain remain elusive. In rodents, electroconvulsive shocks increase proliferation and the expression of plasticity markers in the hippocampal dentate gyrus (DG), suggesting increased neurogenesis. Furthermore, MRI studies in depressed patients have demonstrated increases in DG volume after ECT, that were notably paralleled by a decrease in depressive mood scores. Whether ECT also triggers cellular plasticity, inflammation or possibly injury in the human hippocampus, was unknown. We here performed a first explorative, anatomical study on the human post-mortem hippocampus of a unique, well-documented cohort of bipolar or unipolar depressed patients, who had received ECT in the 5 years prior to their death. They were compared to age-matched patients with a depressive disorder who had not received ECT and to matched healthy controls. Upon histopathological examination, no indications were observed for major hippocampal cell loss, overt cytoarchitectural changes or classic neuropathology in these 3 groups, nor were obvious differences present in inflammatory markers for astrocytes or microglia. Whereas the numbers of proliferating cells expressing Ki-67 was not different, we found a significantly higher percentage of cells positive for Doublecortin, a marker commonly used for young neurons and cellular plasticity, in the subgranular zone and CA4 / hilus of the hippocampus of ECT patients. Also, the percentage of positive Stathmin 1 cells was significantly higher in the subgranular zone of ECT patients, indicating neuroplasticity. These first post-mortem observations suggest that ECT has no damaging effects but may rather have induced neuroplasticity in the DG of depressed patients.
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Affiliation(s)
- Dore Loef
- Amsterdam UMC, location VUmc, Amsterdam, Department of Psychiatry, Amsterdam Neuroscience, Amsterdam, the Netherlands.
- GGZ inGeest Specialized Mental Health Care, Amsterdam, the Netherlands.
| | - Indira Tendolkar
- Department of Psychiatry, Radboud University Medical Center, Nijmegen, the Netherlands
- Donders Institute for Brain, Cognition and Behavior, Centre for Cognitive Neuroimaging, Nijmegen, the Netherlands
- Department of Psychiatry and Psychotherapy, University Hospital Essen, Essen, Germany
| | - Philip F P van Eijndhoven
- Department of Psychiatry, Radboud University Medical Center, Nijmegen, the Netherlands
- Donders Institute for Brain, Cognition and Behavior, Centre for Cognitive Neuroimaging, Nijmegen, the Netherlands
| | - Jeroen J M Hoozemans
- Department of Pathology, Amsterdam Neuroscience, Amsterdam University Medical Centre, Amsterdam, the Netherlands
| | - Mardien L Oudega
- Amsterdam UMC, location VUmc, Amsterdam, Department of Psychiatry, Amsterdam Neuroscience, Amsterdam, the Netherlands
- GGZ inGeest Specialized Mental Health Care, Amsterdam, the Netherlands
| | - Annemieke J M Rozemuller
- Department of Pathology, Amsterdam Neuroscience, Amsterdam University Medical Centre, Amsterdam, the Netherlands
| | - Paul J Lucassen
- Brain Plasticity Group, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, the Netherlands
| | - Annemiek Dols
- Amsterdam UMC, location VUmc, Amsterdam, Department of Psychiatry, Amsterdam Neuroscience, Amsterdam, the Netherlands
- Department of Psychiatry, UMC Utrecht Brain Center, University Utrecht, Utrecht, the Netherlands
| | - Anke A Dijkstra
- Molecular Neuroscience Group, Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, Amsterdam, the Netherlands
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3
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Stöber TM, Batulin D, Triesch J, Narayanan R, Jedlicka P. Degeneracy in epilepsy: multiple routes to hyperexcitable brain circuits and their repair. Commun Biol 2023; 6:479. [PMID: 37137938 PMCID: PMC10156698 DOI: 10.1038/s42003-023-04823-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 04/06/2023] [Indexed: 05/05/2023] Open
Abstract
Due to its complex and multifaceted nature, developing effective treatments for epilepsy is still a major challenge. To deal with this complexity we introduce the concept of degeneracy to the field of epilepsy research: the ability of disparate elements to cause an analogous function or malfunction. Here, we review examples of epilepsy-related degeneracy at multiple levels of brain organisation, ranging from the cellular to the network and systems level. Based on these insights, we outline new multiscale and population modelling approaches to disentangle the complex web of interactions underlying epilepsy and to design personalised multitarget therapies.
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Affiliation(s)
- Tristan Manfred Stöber
- Frankfurt Institute for Advanced Studies, 60438, Frankfurt am Main, Germany
- Institute for Neural Computation, Faculty of Computer Science, Ruhr University Bochum, 44801, Bochum, Germany
- Epilepsy Center Frankfurt Rhine-Main, Department of Neurology, Goethe University, 60590, Frankfurt, Germany
| | - Danylo Batulin
- Frankfurt Institute for Advanced Studies, 60438, Frankfurt am Main, Germany
- CePTER - Center for Personalized Translational Epilepsy Research, Goethe University, 60590, Frankfurt, Germany
- Faculty of Computer Science and Mathematics, Goethe University, 60486, Frankfurt, Germany
| | - Jochen Triesch
- Frankfurt Institute for Advanced Studies, 60438, Frankfurt am Main, Germany
| | - Rishikesh Narayanan
- Cellular Neurophysiology Laboratory, Molecular Biophysics Unit, Indian Institute of Science, Bangalore, 560012, India
| | - Peter Jedlicka
- ICAR3R - Interdisciplinary Centre for 3Rs in Animal Research, Faculty of Medicine, Justus Liebig University Giessen, 35390, Giessen, Germany.
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe University, 60590, Frankfurt am Main, Germany.
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4
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Garcia-Hernandez R, Cerdán Cerdá A, Trouve Carpena A, Drakesmith M, Koller K, Jones DK, Canals S, De Santis S. Mapping microglia and astrocyte activation in vivo using diffusion MRI. SCIENCE ADVANCES 2022; 8:eabq2923. [PMID: 35622913 PMCID: PMC9140964 DOI: 10.1126/sciadv.abq2923] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 04/13/2022] [Indexed: 05/04/2023]
Abstract
While glia are increasingly implicated in the pathophysiology of psychiatric and neurodegenerative disorders, available methods for imaging these cells in vivo involve either invasive procedures or positron emission tomography radiotracers, which afford low resolution and specificity. Here, we present a noninvasive diffusion-weighted magnetic resonance imaging (MRI) method to image changes in glia morphology. Using rat models of neuroinflammation, degeneration, and demyelination, we demonstrate that diffusion-weighted MRI carries a fingerprint of microglia and astrocyte activation and that specific signatures from each population can be quantified noninvasively. The method is sensitive to changes in glia morphology and proliferation, providing a quantitative account of neuroinflammation, regardless of the existence of a concomitant neuronal loss or demyelinating injury. We prove the translational value of the approach showing significant associations between MRI and histological microglia markers in humans. This framework holds the potential to transform basic and clinical research by clarifying the role of inflammation in health and disease.
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Affiliation(s)
| | | | | | - Mark Drakesmith
- CUBRIC, School of Psychology, Cardiff University, Cardiff, UK
| | - Kristin Koller
- CUBRIC, School of Psychology, Cardiff University, Cardiff, UK
| | - Derek K. Jones
- CUBRIC, School of Psychology, Cardiff University, Cardiff, UK
| | - Santiago Canals
- Instituto de Neurociencias, CSIC/UMH, San Juan de Alicante, Alicante, Spain
| | - Silvia De Santis
- Instituto de Neurociencias, CSIC/UMH, San Juan de Alicante, Alicante, Spain
- CUBRIC, School of Psychology, Cardiff University, Cardiff, UK
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5
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Santos VR, Melo IS, Pacheco ALD, Castro OWD. Life and death in the hippocampus: What's bad? Epilepsy Behav 2021; 121:106595. [PMID: 31759972 DOI: 10.1016/j.yebeh.2019.106595] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 09/30/2019] [Accepted: 10/01/2019] [Indexed: 01/13/2023]
Abstract
The hippocampal formation is crucial for the generation and regulation of several brain functions, including memory and learning processes; however, it is vulnerable to neurological disorders, such as epilepsy. Temporal lobe epilepsy (TLE), the most common type of epilepsy, changes the hippocampal circuitry and excitability, under the contribution of both neuronal degeneration and abnormal neurogenesis. Classically, neurodegeneration affects sensitive areas of the hippocampus, such as dentate gyrus (DG) hilus, as well as specific fields of the Ammon's horn, CA3, and CA1. In addition, the proliferation, migration, and abnormal integration of newly generated hippocampal granular cells (GCs) into the brain characterize TLE neurogenesis. Robust studies over the years have intensely discussed the effects of death and life in the hippocampus, though there are still questions to be answered about their possible benefits and risks. Here, we review the impacts of death and life in the hippocampus, discussing its influence on TLE, providing new perspectives or insights for the implementation of new possible therapeutic targets. This article is part of the Special Issue "NEWroscience 2018".
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Affiliation(s)
- Victor Rodrigues Santos
- Department of Morphology, Institute of Biological Sciences, Federal University of Minas Gerais (UFMG), Belo Horizonte, Brazil.
| | - Igor Santana Melo
- Institute of Biological Sciences and Health, Federal University of Alagoas (UFAL), Maceio, Brazil
| | | | - Olagide Wagner de Castro
- Institute of Biological Sciences and Health, Federal University of Alagoas (UFAL), Maceio, Brazil.
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6
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Lazarini-Lopes W, da Silva-Júnior RMP, Servilha-Menezes G, Do Val-da Silva RA, Garcia-Cairasco N. Cannabinoid Receptor Type 1 (CB1R) Expression in Limbic Brain Structures After Acute and Chronic Seizures in a Genetic Model of Epilepsy. Front Behav Neurosci 2020; 14:602258. [PMID: 33408620 PMCID: PMC7779524 DOI: 10.3389/fnbeh.2020.602258] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 11/23/2020] [Indexed: 01/25/2023] Open
Abstract
The endocannabinoid system (ECS) is related to several physiological processes, associated to the modulation of brain excitability, with impact in the expression of susceptibility and control of epileptic seizures. The cannabinoid receptor type 1 (CB1R) is widely expressed in the brain, especially in forebrain limbic structures. Changes in CB1R expression are associated with epileptic seizures in animal models and humans. The Wistar Audiogenic Rat (WAR) strain is a genetic model of epilepsy capable of mimicking tonic-clonic and limbic seizures in response to intense sound stimulation. The WAR strain presents several behavioral and physiological alterations associated with seizure susceptibility, but the ECS has never been explored in this strain. Therefore, the aim of the present study was to characterize CB1R expression in forebrain limbic structures important to limbic seizure expression in WARs. We used a detailed anatomical analysis to assess the effects of acute and chronic audiogenic seizures on CB1R expression in several layers and regions of hippocampus and amygdala. WARs showed increased CB1R immunostaining in the inner molecular layer of the hippocampus, when compared to control Wistar rats. Acute and chronic audiogenic seizures increased CB1R immunostaining in several regions of the dorsal hippocampus and amygdala of WARs. Also, changes in CB1R expression in the amygdala, but not in the hippocampus, were associated with limbic recruitment and limbic seizure severity in WARs. Our results suggest that endogenous alterations in CB1R immunostaining in WARs could be associated with genetic susceptibility to audiogenic seizures. We also demonstrated CB1R neuroplastic changes associated with acute and chronic seizures in the amygdala and hippocampus. Moreover, the present study brings important information regarding CB1R and seizure susceptibility in a genetic model of seizures and supports the relationship between ECS and epilepsy.
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Affiliation(s)
- Willian Lazarini-Lopes
- Neuroscience and Behavioral Sciences Department, Ribeirão Preto School of Medicine, University of São Paulo, Ribeirão Preto, Brazil.,Neurophysiology and Experimental Neuroethology Laboratory, Physiology Department, Ribeirão Preto School of Medicine, University of São Paulo, Ribeirão Preto, Brazil
| | - Rui M P da Silva-Júnior
- Neurophysiology and Experimental Neuroethology Laboratory, Physiology Department, Ribeirão Preto School of Medicine, University of São Paulo, Ribeirão Preto, Brazil.,Department of Internal Medicine, Ribeirão Preto School of Medicine, University of São Paulo, Ribeirão Preto, Brazil
| | - Gabriel Servilha-Menezes
- Neurophysiology and Experimental Neuroethology Laboratory, Physiology Department, Ribeirão Preto School of Medicine, University of São Paulo, Ribeirão Preto, Brazil
| | - Raquel A Do Val-da Silva
- Neuroscience and Behavioral Sciences Department, Ribeirão Preto School of Medicine, University of São Paulo, Ribeirão Preto, Brazil
| | - Norberto Garcia-Cairasco
- Neuroscience and Behavioral Sciences Department, Ribeirão Preto School of Medicine, University of São Paulo, Ribeirão Preto, Brazil.,Neurophysiology and Experimental Neuroethology Laboratory, Physiology Department, Ribeirão Preto School of Medicine, University of São Paulo, Ribeirão Preto, Brazil
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7
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Farhoodi R, Lansdell BJ, Kording KP. Quantifying How Staining Methods Bias Measurements of Neuron Morphologies. Front Neuroinform 2019; 13:36. [PMID: 31191283 PMCID: PMC6541099 DOI: 10.3389/fninf.2019.00036] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Accepted: 04/25/2019] [Indexed: 12/20/2022] Open
Abstract
The process through which neurons are labeled is a key methodological choice in measuring neuron morphology. However, little is known about how this choice may bias measurements. To quantify this bias we compare the extracted morphology of neurons collected from the same rodent species, experimental condition, gender distribution, age distribution, brain region and putative cell type, but obtained with 19 distinct staining methods. We found strong biases on measured features of morphology. These were largest in features related to the coverage of the dendritic tree (e.g., the total dendritic tree length). Understanding measurement biases is crucial for interpreting morphological data.
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Affiliation(s)
- Roozbeh Farhoodi
- Department of Mathematics, Sharif University of Technology, Tehran, Iran
| | | | - Konrad Paul Kording
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, United States.,Department of Neuroscience, University of Pennsylvania, Philadelphia, PA, United States
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8
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Restrained Dendritic Growth of Adult-Born Granule Cells Innervated by Transplanted Fetal GABAergic Interneurons in Mice with Temporal Lobe Epilepsy. eNeuro 2019; 6:ENEURO.0110-18.2019. [PMID: 31043461 PMCID: PMC6497906 DOI: 10.1523/eneuro.0110-18.2019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 03/11/2019] [Accepted: 03/15/2019] [Indexed: 12/16/2022] Open
Abstract
The dentate gyrus (DG) is a region of the adult rodent brain that undergoes continuous neurogenesis. Seizures and loss or dysfunction of GABAergic synapses onto adult-born dentate granule cells (GCs) alter their dendritic growth and migration, resulting in dysmorphic and hyperexcitable GCs. Additionally, transplants of fetal GABAergic interneurons in the DG of mice with temporal lobe epilepsy (TLE) result in seizure suppression, but it is unknown whether increasing interneurons with these transplants restores GABAergic innervation to adult-born GCs. Here, we address this question by birth-dating GCs with retrovirus at different times up to 12 weeks after pilocarpine-induced TLE in adult mice. Channelrhodopsin 2 (ChR2)-enhanced yellow fluorescent protein (EYFP)-expressing medial-ganglionic eminence (MGE)-derived GABAergic interneurons from embryonic day (E)13.5 mouse embryos were transplanted into the DG of the TLE mice and GCs with transplant-derived inhibitory post-synaptic currents (IPSCs) were identified by patch-clamp electrophysiology and optogenetic interrogation. Putative synaptic sites between GCs and GABAergic transplants were also confirmed by intracellular biocytin staining, immunohistochemistry, and confocal imaging. 3D reconstructions of dendritic arbors and quantitative morphometric analyses were carried out in >150 adult-born GCs. GABAergic inputs from transplanted interneurons correlated with markedly shorter GC dendrites, compared to GCs that were not innervated by the transplants. Moreover, these effects were confined to distal dendritic branches and a short time window of six to eight weeks. The effects were independent of seizures as they were also observed in naïve mice with MGE transplants. These findings are consistent with the hypothesis that increased inhibitory currents over a smaller dendritic arbor in adult-born GCs may reduce their excitability and lead to seizure suppression.
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9
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Umeoka EHL, Robinson EJ, Turimella SL, van Campen JS, Motta-Teixeira LC, Sarabdjitsingh RA, Garcia-Cairasco N, Braun K, de Graan PN, Joëls M. Hyperthermia-induced seizures followed by repetitive stress are associated with age-dependent changes in specific aspects of the mouse stress system. J Neuroendocrinol 2019; 31:e12697. [PMID: 30773738 DOI: 10.1111/jne.12697] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 02/04/2019] [Accepted: 02/13/2019] [Indexed: 11/28/2022]
Abstract
Stress is among the most frequently self-reported factors provoking epileptic seizures in children and adults. It is still unclear, however, why some people display stress-sensitive seizures and others do not. Recently, we showed that young epilepsy patients with stress-sensitive seizures exhibit a dysregulated hypothalamic-pituitary-adrenal (HPA)-axis. Most likely, this dysregulation gradually develops, and is triggered by stressors occurring early in life (early-life stress [ELS]). ELS may be particularly impactful when overlapping with the period of epileptogenesis. To examine this in a controlled and prospective manner, the present study investigated the effect of repetitive variable stressors or control treatment between postnatal day (PND) 12 and 24 in male mice exposed on PND10 to hyperthermia (HT)-induced prolonged seizures (control: normothermia). A number of peripheral and central indices of HPA-axis activity were evaluated at pre-adolescent and young adult age (ie, at PND25 and 90, respectively). At PND25 but not at PND90, body weight gain and absolute as well as relative (to body weight) thymus weight were reduced by ELS (vs control), whereas relative adrenal weight was enhanced, confirming the effectiveness of the stress treatment. Basal and stress-induced corticosterone levels were unaffected, though, by ELS at both ages. HT by itself did not affect any of these peripheral markers of HPA-axis activity, nor did it interact with ELS. However, centrally we did observe age-specific interaction effects of HT and ELS with regard to hippocampal glucocorticoid receptor mRNA expression, neurogenesis with the immature neurone marker doublecortin and the number of hilar (ectopic) granule cells using Prox1 staining. This lends some support to the notion that exposure to repetitive stress after HT-induced seizures may dysregulate central components of the stress system in an age-dependent manner. Such dysregulation could be one of the mechanisms conferring higher vulnerability of individuals with epilepsy to develop seizures in the face of stress.
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Affiliation(s)
- Eduardo H L Umeoka
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, University of Utrecht, Utrecht, The Netherlands
- Neuroscience and Behavioral Sciences Department, Ribeirão Preto School of Medicine, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Edward J Robinson
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, University of Utrecht, Utrecht, The Netherlands
- Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - Sada Lakshmi Turimella
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, University of Utrecht, Utrecht, The Netherlands
| | - Jolien S van Campen
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, University of Utrecht, Utrecht, The Netherlands
- Department of Pediatric Neurology, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Lívia C Motta-Teixeira
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
| | - R Angela Sarabdjitsingh
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, University of Utrecht, Utrecht, The Netherlands
| | - Norberto Garcia-Cairasco
- Neuroscience and Behavioral Sciences Department, Ribeirão Preto School of Medicine, University of São Paulo, Ribeirão Preto, SP, Brazil
- Physiology Department, Ribeirão Preto School of Medicine, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Kees Braun
- Department of Pediatric Neurology, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Pierre N de Graan
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, University of Utrecht, Utrecht, The Netherlands
| | - Marian Joëls
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, University of Utrecht, Utrecht, The Netherlands
- University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
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10
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Beamer EH, Jurado-Arjona J, Jimenez-Mateos EM, Morgan J, Reschke CR, Kenny A, de Leo G, Olivos-Oré LA, Arribas-Blázquez M, Madden SF, Merchán-Rubira J, Delanty N, Farrell MA, O'Brien DF, Avila J, Diaz-Hernandez M, Miras-Portugal MT, Artalejo AR, Hernandez F, Henshall DC, Engel T. MicroRNA-22 Controls Aberrant Neurogenesis and Changes in Neuronal Morphology After Status Epilepticus. Front Mol Neurosci 2018; 11:442. [PMID: 30618601 PMCID: PMC6298134 DOI: 10.3389/fnmol.2018.00442] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 11/16/2018] [Indexed: 12/12/2022] Open
Abstract
Prolonged seizures (status epilepticus, SE) may drive hippocampal dysfunction and epileptogenesis, at least partly, through an elevation in neurogenesis, dysregulation of migration and aberrant dendritic arborization of newly-formed neurons. MicroRNA-22 was recently found to protect against the development of epileptic foci, but the mechanisms remain incompletely understood. Here, we investigated the contribution of microRNA-22 to SE-induced aberrant adult neurogenesis. SE was induced by intraamygdala microinjection of kainic acid (KA) to model unilateral hippocampal neuropathology in mice. MicroRNA-22 expression was suppressed using specific oligonucleotide inhibitors (antagomir-22) and newly-formed neurons were visualized using the thymidine analog iodo-deoxyuridine (IdU) and a green fluorescent protein (GFP)-expressing retrovirus to visualize the dendritic tree and synaptic spines. Using this approach, we quantified differences in the rate of neurogenesis and migration, the structure of the apical dendritic tree and density and morphology of dendritic spines in newly-formed neurons.SE resulted in an increased rate of hippocampal neurogenesis, including within the undamaged contralateral dentate gyrus (DG). Newly-formed neurons underwent aberrant migration, both within the granule cell layer and into ectopic sites. Inhibition of microRNA-22 exacerbated these changes. The dendritic diameter and the density and average volume of dendritic spines were unaffected by SE, but these parameters were all elevated in mice in which microRNA-22 was suppressed. MicroRNA-22 inhibition also reduced the length and complexity of the dendritic tree, independently of SE. These data indicate that microRNA-22 is an important regulator of morphogenesis of newly-formed neurons in adults and plays a role in supressing aberrant neurogenesis associated with SE.
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Affiliation(s)
- Edward H Beamer
- Department of Physiology & Medical Physics, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Jeronimo Jurado-Arjona
- Institute of Physiological Chemistry, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany.,Department of Molecular Biology, Centro de Biología Molecular "Severo Ochoa", Consejo Superior de Investigaciones Científicas (CSIC), Universidad Autónoma de Madrid (UAM), Centro Investigación Biomédica en Red Enfermedades Neurodegenerativa (CIBERNED), Madrid, Spain
| | - Eva M Jimenez-Mateos
- Department of Physiology & Medical Physics, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - James Morgan
- Department of Physiology & Medical Physics, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Cristina R Reschke
- Department of Physiology & Medical Physics, Royal College of Surgeons in Ireland, Dublin, Ireland.,FutureNeuro Research Centre, RCSI, Dublin, Ireland
| | - Aidan Kenny
- Department of Physiology & Medical Physics, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Gioacchino de Leo
- Department of Physiology & Medical Physics, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Luis A Olivos-Oré
- Department of Pharmacology and Toxicology, Veterinary Faculty, Instituto Universitario de Investigación en Neuroquímica, Universidad Complutense de Madrid, Madrid, Spain
| | - Marina Arribas-Blázquez
- Department of Pharmacology and Toxicology, Veterinary Faculty, Instituto Universitario de Investigación en Neuroquímica, Universidad Complutense de Madrid, Madrid, Spain
| | - Stephen F Madden
- Data Science Centre, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Jesús Merchán-Rubira
- Department of Molecular Biology, Centro de Biología Molecular "Severo Ochoa", Consejo Superior de Investigaciones Científicas (CSIC), Universidad Autónoma de Madrid (UAM), Centro Investigación Biomédica en Red Enfermedades Neurodegenerativa (CIBERNED), Madrid, Spain
| | - Norman Delanty
- FutureNeuro Research Centre, RCSI, Dublin, Ireland.,Beaumont Hospital, Dublin, Ireland
| | | | | | - Jesus Avila
- Department of Molecular Biology, Centro de Biología Molecular "Severo Ochoa", Consejo Superior de Investigaciones Científicas (CSIC), Universidad Autónoma de Madrid (UAM), Centro Investigación Biomédica en Red Enfermedades Neurodegenerativa (CIBERNED), Madrid, Spain
| | - Miguel Diaz-Hernandez
- Department of Biochemistry and Molecular Biology, Veterinary Faculty, Universidad Complutense de Madrid, Madrid, Spain
| | - M Teresa Miras-Portugal
- Department of Biochemistry and Molecular Biology, Veterinary Faculty, Universidad Complutense de Madrid, Madrid, Spain
| | - Antonio R Artalejo
- Department of Pharmacology and Toxicology, Veterinary Faculty, Instituto Universitario de Investigación en Neuroquímica, Universidad Complutense de Madrid, Madrid, Spain
| | - Felix Hernandez
- Department of Molecular Biology, Centro de Biología Molecular "Severo Ochoa", Consejo Superior de Investigaciones Científicas (CSIC), Universidad Autónoma de Madrid (UAM), Centro Investigación Biomédica en Red Enfermedades Neurodegenerativa (CIBERNED), Madrid, Spain
| | - David C Henshall
- Department of Physiology & Medical Physics, Royal College of Surgeons in Ireland, Dublin, Ireland.,FutureNeuro Research Centre, RCSI, Dublin, Ireland
| | - Tobias Engel
- Department of Physiology & Medical Physics, Royal College of Surgeons in Ireland, Dublin, Ireland.,FutureNeuro Research Centre, RCSI, Dublin, Ireland
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11
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Godale CM, Danzer SC. Signaling Pathways and Cellular Mechanisms Regulating Mossy Fiber Sprouting in the Development of Epilepsy. Front Neurol 2018; 9:298. [PMID: 29774009 PMCID: PMC5943493 DOI: 10.3389/fneur.2018.00298] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 04/17/2018] [Indexed: 02/04/2023] Open
Abstract
The sprouting of hippocampal dentate granule cell axons, termed mossy fibers, into the dentate inner molecular layer is one of the most consistent findings in tissue from patients with mesial temporal lobe epilepsy. Decades of research in animal models have revealed that mossy fiber sprouting creates de novo recurrent excitatory connections in the hippocampus, fueling speculation that the pathology may drive temporal lobe epileptogenesis. Conducting definitive experiments to test this hypothesis, however, has been challenging due to the difficulty of dissociating this sprouting from the many other changes occurring during epileptogenesis. The field has been largely driven, therefore, by correlative data. Recently, the development of powerful transgenic mouse technologies and the discovery of novel drug targets has provided new tools to assess the role of mossy fiber sprouting in epilepsy. We can now selectively manipulate hippocampal granule cells in rodent epilepsy models, providing new insights into the granule cell subpopulations that participate in mossy fiber sprouting. The cellular pathways regulating this sprouting are also coming to light, providing new targets for pharmacological intervention. Surprisingly, many investigators have found that blocking mossy fiber sprouting has no effect on seizure occurrence, while seizure frequency can be reduced by treatments that have no effect on this sprouting. These results raise new questions about the role of mossy fiber sprouting in epilepsy. Here, we will review these findings with particular regard to the contributions of new granule cells to mossy fiber sprouting and the regulation of this sprouting by the mTOR signaling pathway.
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Affiliation(s)
- Christin M Godale
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States.,Neuroscience Graduate Program, University of Cincinnati, Cincinnati, OH, United States
| | - Steve C Danzer
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States.,Neuroscience Graduate Program, University of Cincinnati, Cincinnati, OH, United States.,Department of Anesthesia, University of Cincinnati, Cincinnati, OH, United States.,Department of Pediatrics, University of Cincinnati, Cincinnati, OH, United States
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12
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Jarero-Basulto JJ, Gasca-Martínez Y, Rivera-Cervantes MC, Ureña-Guerrero ME, Feria-Velasco AI, Beas-Zarate C. Interactions Between Epilepsy and Plasticity. Pharmaceuticals (Basel) 2018; 11:ph11010017. [PMID: 29414852 PMCID: PMC5874713 DOI: 10.3390/ph11010017] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Revised: 02/01/2018] [Accepted: 02/06/2018] [Indexed: 02/06/2023] Open
Abstract
Undoubtedly, one of the most interesting topics in the field of neuroscience is the ability of the central nervous system to respond to different stimuli (normal or pathological) by modifying its structure and function, either transiently or permanently, by generating neural cells and new connections in a process known as neuroplasticity. According to the large amount of evidence reported in the literature, many stimuli, such as environmental pressures, changes in the internal dynamic steady state of the organism and even injuries or illnesses (e.g., epilepsy) may induce neuroplasticity. Epilepsy and neuroplasticity seem to be closely related, as the two processes could positively affect one another. Thus, in this review, we analysed some neuroplastic changes triggered in the hippocampus in response to seizure-induced neuronal damage and how these changes could lead to the establishment of temporal lobe epilepsy, the most common type of focal human epilepsy.
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Affiliation(s)
- José J Jarero-Basulto
- Cellular Neurobiology Laboratory, Cell and Molecular Biology Department, CUCBA, University of Guadalajara, 45220 Zapopan, Jalisco, Mexico.
| | - Yadira Gasca-Martínez
- Cellular Neurobiology Laboratory, Cell and Molecular Biology Department, CUCBA, University of Guadalajara, 45220 Zapopan, Jalisco, Mexico.
| | - Martha C Rivera-Cervantes
- Cellular Neurobiology Laboratory, Cell and Molecular Biology Department, CUCBA, University of Guadalajara, 45220 Zapopan, Jalisco, Mexico.
| | - Mónica E Ureña-Guerrero
- Neurotransmission Biology Laboratory, Cell and Molecular Biology Department, CUCBA, University of Guadalajara, 45220 Zapopan, Jalisco, Mexico.
| | - Alfredo I Feria-Velasco
- Cellular Neurobiology Laboratory, Cell and Molecular Biology Department, CUCBA, University of Guadalajara, 45220 Zapopan, Jalisco, Mexico.
| | - Carlos Beas-Zarate
- Development and Neural Regeneration Laboratory, Cell and Molecular Biology Department, CUCBA, University of Guadalajara, 45220 Zapopan, Jalisco, Mexico.
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13
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Navidhamidi M, Ghasemi M, Mehranfard N. Epilepsy-associated alterations in hippocampal excitability. Rev Neurosci 2018; 28:307-334. [PMID: 28099137 DOI: 10.1515/revneuro-2016-0059] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Accepted: 11/03/2016] [Indexed: 11/15/2022]
Abstract
The hippocampus exhibits a wide range of epilepsy-related abnormalities and is situated in the mesial temporal lobe, where limbic seizures begin. These abnormalities could affect membrane excitability and lead to overstimulation of neurons. Multiple overlapping processes refer to neural homeostatic responses develop in neurons that work together to restore neuronal firing rates to control levels. Nevertheless, homeostatic mechanisms are unable to restore normal neuronal excitability, and the epileptic hippocampus becomes hyperexcitable or hypoexcitable. Studies show that there is hyperexcitability even before starting recurrent spontaneous seizures, suggesting although hippocampal hyperexcitability may contribute to epileptogenesis, it alone is insufficient to produce epileptic seizures. This supports the concept that the hippocampus is not the only substrate for limbic seizure onset, and a broader hyperexcitable limbic structure may contribute to temporal lobe epilepsy (TLE) seizures. Nevertheless, seizures also occur in conditions where the hippocampus shows a hypoexcitable phenotype. Since TLE seizures most often originate in the hippocampus, it could therefore be assumed that both hippocampal hypoexcitability and hyperexcitability are undesirable states that make the epileptic hippocampal network less stable and may, under certain conditions, trigger seizures.
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14
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Garcia-Cairasco N, Umeoka EHL, Cortes de Oliveira JA. The Wistar Audiogenic Rat (WAR) strain and its contributions to epileptology and related comorbidities: History and perspectives. Epilepsy Behav 2017; 71:250-273. [PMID: 28506440 DOI: 10.1016/j.yebeh.2017.04.001] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
In the context of modeling epilepsy and neuropsychiatric comorbidities, we review the Wistar Audiogenic Rat (WAR), first introduced to the neuroscience international community more than 25years ago. The WAR strain is a genetically selected reflex model susceptible to audiogenic seizures (AS), acutely mimicking brainstem-dependent tonic-clonic seizures and chronically (by audiogenic kindling), temporal lobe epilepsy (TLE). Seminal neuroethological, electrophysiological, cellular, and molecular protocols support the WAR strain as a suitable and reliable animal model to study the complexity and emergent functions typical of epileptogenic networks. Furthermore, since epilepsy comorbidities have emerged as a hot topic in epilepsy research, we discuss the use of WARs in fields such as neuropsychiatry, memory and learning, neuroplasticity, neuroendocrinology, and cardio-respiratory autonomic regulation. Last, but not least, we propose that this strain be used in "omics" studies, as well as with the most advanced molecular and computational modeling techniques. Collectively, pioneering and recent findings reinforce the complexity associated with WAR alterations, consequent to the combination of their genetically-dependent background and seizure profile. To add to previous studies, we are currently developing more powerful behavioral, EEG, and molecular methods, combined with computational neuroscience/network modeling tools, to further increase the WAR strain's contributions to contemporary neuroscience in addition to increasing knowledge in a wide array of neuropsychiatric and other comorbidities, given shared neural networks. During the many years that the WAR strain has been studied, a constantly expanding network of multidisciplinary collaborators has generated a growing research and knowledge network. Our current and major wish is to make the WARs available internationally to share our knowledge and to facilitate the planning and execution of multi-institutional projects, eagerly needed to contribute to paradigm shifts in epileptology. This article is part of a Special Issue entitled "Genetic and Reflex Epilepsies, Audiogenic Seizures and Strains: From Experimental Models to the Clinic".
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Affiliation(s)
- Norberto Garcia-Cairasco
- Physiology Department, Ribeirão Preto School of Medicine, University of São Paulo, Brazil; Neuroscience and Behavioral Sciences Department, Ribeirão Preto School of Medicine, University of São Paulo, Brazil.
| | - Eduardo H L Umeoka
- Physiology Department, Ribeirão Preto School of Medicine, University of São Paulo, Brazil; Neuroscience and Behavioral Sciences Department, Ribeirão Preto School of Medicine, University of São Paulo, Brazil
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15
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Salo RA, Miettinen T, Laitinen T, Gröhn O, Sierra A. Diffusion tensor MRI shows progressive changes in the hippocampus and dentate gyrus after status epilepticus in rat - histological validation with Fourier-based analysis. Neuroimage 2017; 152:221-236. [PMID: 28267625 DOI: 10.1016/j.neuroimage.2017.03.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 01/27/2017] [Accepted: 03/02/2017] [Indexed: 01/17/2023] Open
Abstract
Imaging markers for monitoring disease progression, recovery, and treatment efficacy are a major unmet need for many neurological diseases, including epilepsy. Recent evidence suggests that diffusion tensor imaging (DTI) provides high microstructural contrast even outside major white matter tracts. We hypothesized that in vivo DTI could detect progressive microstructural changes in the dentate gyrus and the hippocampal CA3bc in the rat brain after status epilepticus (SE). To test this hypothesis, we induced SE with systemic kainic acid or pilocarpine in adult male Wistar rats and subsequently scanned them using in vivo DTI at five time-points: prior to SE, and 10, 20, 34, and 79 days post SE. In order to tie the DTI findings to changes in the tissue microstructure, myelin- and glial fibrillary acidic protein (GFAP)-stained sections from the same animals underwent Fourier analysis. We compared the Fourier analysis parameters, anisotropy index and angle of myelinated axons or astrocyte processes, to corresponding DTI parameters, fractional anisotropy (FA) and the orientation angle of the principal eigenvector. We found progressive detectable changes in DTI parameters in both the dentate gyrus (FA, axial diffusivity [D||], linear anisotropy [CL] and spherical anisotropy [CS], p<0.001, linear mixed-effects model [LMEM]) and the CA3bc (FA, D||, CS, and angle, p<0.001, LMEM; CL and planar anisotropy [CP], p<0.01, LMEM) post SE. The Fourier analysis revealed that both myelinated axons and astrocyte processes played a role in the water diffusion anisotropy changes detected by DTI in individual portions of the dentate gyrus (suprapyramidal blade, mid-portion, and infrapyramidal blade). In the whole dentate gyrus, myelinated axons markedly contributed to the water diffusion changes. In CA3bc as well as in CA3b and CA3c, both myelinated axons and astrocyte processes contributed to water diffusion anisotropy and orientation. Our study revealed that DTI is a promising method for noninvasive detection of microstructural alterations in the hippocampus proper. These alterations may be potential imaging markers for epileptogenesis.
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Affiliation(s)
- Raimo A Salo
- Department of Neurobiology, A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, PO Box 1627, FI-70211 Kuopio, Finland
| | - Tuukka Miettinen
- Department of Neurobiology, A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, PO Box 1627, FI-70211 Kuopio, Finland
| | - Teemu Laitinen
- Department of Neurobiology, A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, PO Box 1627, FI-70211 Kuopio, Finland
| | - Olli Gröhn
- Department of Neurobiology, A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, PO Box 1627, FI-70211 Kuopio, Finland
| | - Alejandra Sierra
- Department of Neurobiology, A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, PO Box 1627, FI-70211 Kuopio, Finland.
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16
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Soares LM, De Vry J, Steinbusch HW, Milani H, Prickaerts J, Weffort de Oliveira RM. Rolipram improves cognition, reduces anxiety- and despair-like behaviors and impacts hippocampal neuroplasticity after transient global cerebral ischemia. Neuroscience 2016; 326:69-83. [DOI: 10.1016/j.neuroscience.2016.03.062] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 03/28/2016] [Accepted: 03/30/2016] [Indexed: 12/11/2022]
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17
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Up-regulated ephrinB3/EphB3 expression in intractable temporal lobe epilepsy patients and pilocarpine induced experimental epilepsy rat model. Brain Res 2016; 1639:1-12. [DOI: 10.1016/j.brainres.2016.02.035] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2015] [Revised: 01/31/2016] [Accepted: 02/21/2016] [Indexed: 02/01/2023]
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18
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Llorens-Martín M, Rábano A, Ávila J. The Ever-Changing Morphology of Hippocampal Granule Neurons in Physiology and Pathology. Front Neurosci 2016; 9:526. [PMID: 26834550 PMCID: PMC4717329 DOI: 10.3389/fnins.2015.00526] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 12/29/2015] [Indexed: 11/29/2022] Open
Abstract
Newborn neurons are continuously added to the hippocampal dentate gyrus throughout adulthood. In this review, we analyze the maturational stages that newborn granule neurons go through, with a focus on their unique morphological features during each stage under both physiological and pathological circumstances. In addition, the influence of deleterious (such as schizophrenia, stress, Alzheimer's disease, seizures, stroke, inflammation, dietary deficiencies, or the consumption of drugs of abuse or toxic substances) and neuroprotective (physical exercise and environmental enrichment) stimuli on the maturation of these cells will be examined. Finally, the regulation of this process by proteins involved in neurodegenerative and neurological disorders such as Glycogen synthase kinase 3β, Disrupted in Schizophrenia 1 (DISC-1), Glucocorticoid receptor, pro-inflammatory mediators, Presenilin-1, Amyloid precursor protein, Cyclin-dependent kinase 5 (CDK5), among others, will be evaluated. Given the recently acquired relevance of the dendritic branch as a functional synaptic unit required for memory storage, a full understanding of the morphological alterations observed in newborn neurons may have important consequences for the prevention and treatment of the cognitive and affective alterations that evolve in conjunction with impaired adult hippocampal neurogenesis.
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Affiliation(s)
- María Llorens-Martín
- Molecular Neurobiology, Function of Microtubular Proteins, Centro de Biología Molecular Severo Ochoa (Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid)Madrid, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (Instituto de Salud Carlos III)Madrid, Spain
| | - Alberto Rábano
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (Instituto de Salud Carlos III)Madrid, Spain; Neuropathology Department, CIEN FoundationMadrid, Spain
| | - Jesús Ávila
- Molecular Neurobiology, Function of Microtubular Proteins, Centro de Biología Molecular Severo Ochoa (Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid)Madrid, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (Instituto de Salud Carlos III)Madrid, Spain
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19
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Gao F, Song X, Zhu D, Wang X, Hao A, Nadler JV, Zhan RZ. Dendritic morphology, synaptic transmission, and activity of mature granule cells born following pilocarpine-induced status epilepticus in the rat. Front Cell Neurosci 2015; 9:384. [PMID: 26500490 PMCID: PMC4596052 DOI: 10.3389/fncel.2015.00384] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2015] [Accepted: 09/14/2015] [Indexed: 01/23/2023] Open
Abstract
To understand the potential role of enhanced hippocampal neurogenesis after pilocarpine-induced status epilepticus (SE) in the development of epilepsy, we quantitatively analyzed the geometry of apical dendrites, synaptic transmission, and activation levels of normotopically distributed mature newborn granule cells in the rat. SE in male Sprague-Dawley rats (between 6 and 7 weeks old) lasting for more than 2 h was induced by an intraperitoneal injection of pilocarpine. The complexity, spine density, miniature post-synaptic currents, and activity-regulated cytoskeleton-associated protein (Arc) expression of granule cells born 5 days after SE were studied between 10 and 17 weeks after CAG-GFP retroviral vector-mediated labeling. Mature granule cells born after SE had dendritic complexity similar to that of granule cells born naturally, but with denser mushroom-like spines in dendritic segments located in the outer molecular layer. Miniature inhibitory post-synaptic currents (mIPSCs) were similar between the controls and rats subjected to SE; however, smaller miniature excitatory post-synaptic current (mEPSC) amplitude with a trend toward less frequent was found in mature granule cells born after SE. After maturation, granule cells born after SE did not show denser Arc expression in the resting condition or 2 h after being activated by pentylenetetrazol-induced transient seizure activity than vicinal GFP-unlabeled granule cells. Thus our results suggest that normotopic granule cells born after pilocarpine-induced SE are no more active when mature than age-matched, naturally born granule cells.
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Affiliation(s)
- Fei Gao
- Department of Physiology, Shandong University School of Medicine Jinan, China
| | - Xueying Song
- Department of Physiology, Shandong University School of Medicine Jinan, China
| | - Dexiao Zhu
- Department of Physiology, Shandong University School of Medicine Jinan, China
| | - Xiaochen Wang
- Department of Physiology, Shandong University School of Medicine Jinan, China
| | - Aijun Hao
- Department of Histology and Embryology, Shandong University School of Medicine Jinan, China
| | - J Victor Nadler
- Departments of Pharmacology and Neurobiology, Duke University Medical Center Durham, NC, USA
| | - Ren-Zhi Zhan
- Department of Physiology, Shandong University School of Medicine Jinan, China
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20
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Latchney SE, Jiang Y, Petrik DP, Eisch AJ, Hsieh J. Inducible knockout of Mef2a, -c, and -d from nestin-expressing stem/progenitor cells and their progeny unexpectedly uncouples neurogenesis and dendritogenesis in vivo. FASEB J 2015; 29:5059-71. [PMID: 26286136 DOI: 10.1096/fj.15-275651] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2015] [Accepted: 08/13/2015] [Indexed: 12/11/2022]
Abstract
Myocyte enhancer factor (Mef)-2 transcription factors are implicated in activity-dependent neuronal processes during development, but the role of MEF2 in neural stem/progenitor cells (NSPCs) in the adult brain is unknown. We used a transgenic mouse in which Mef2a, -c, and -d were inducibly deleted in adult nestin-expressing NSPCs and their progeny. Recombined cells in the hippocampal granule cell layer were visualized and quantified by yellow fluorescent protein (YFP) expression. In control mice, postmitotic neurons expressed Mef2a, -c, and -d, whereas type 1 stem cells and proliferating progenitors did not. Based on this expression, we hypothesized that Mef2a, -c, and -d deletion in adult nestin-expressing NSPCs and their progeny would result in fewer mature neurons. Control mice revealed an increase in YFP(+) neurons and dendrite formation over time. Contrary to our hypothesis, inducible Mef2 KO mice also displayed an increase in YFP(+) neurons over time-but with significantly stunted dendrites-suggesting an uncoupling of neuron survival and dendritogenesis. We also found non-cell-autonomous effects after Mef2a, -c, and -d deletion. These in vivo findings indicate a surprising functional role for Mef2a, -c, and -d in cell- and non-cell-autonomous control of adult hippocampal neurogenesis that is distinct from its role during development.
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Affiliation(s)
- Sarah E Latchney
- *Department of Psychiatry and Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Yindi Jiang
- *Department of Psychiatry and Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - David P Petrik
- *Department of Psychiatry and Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Amelia J Eisch
- *Department of Psychiatry and Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Jenny Hsieh
- *Department of Psychiatry and Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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21
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Lima IVDA, Campos AC, Miranda AS, Vieira ÉLM, Amaral-Martins F, Vago JP, Santos RPDM, Sousa LP, Vieira LB, Teixeira MM, Fiebich BL, Moraes MFD, Teixeira AL, de Oliveira ACP. PI3Kγ deficiency enhances seizures severity and associated outcomes in a mouse model of convulsions induced by intrahippocampal injection of pilocarpine. Exp Neurol 2015; 267:123-34. [PMID: 25749189 DOI: 10.1016/j.expneurol.2015.02.021] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Revised: 01/22/2015] [Accepted: 02/18/2015] [Indexed: 11/16/2022]
Abstract
Phosphatidylinositol 3-kinase (PI3K) is an enzyme involved in different pathophysiological processes, including neurological disorders. However, its role in seizures and postictal outcomes is still not fully understood. We investigated the role of PI3Kγ on seizures, production of neurotrophic and inflammatory mediators, expression of a marker for microglia, neuronal death and hippocampal neurogenesis in mice (WT and PI3Kγ(-/-)) subjected to intrahippocampal microinjection of pilocarpine. PI3Kγ(-/-) mice presented a more severe status epilepticus (SE) than WT mice. In hippocampal synaptosomes, genetic or pharmacological blockade of PI3Kγ enhanced the release of glutamate and the cytosolic calcium concentration induced by KCl. There was an enhanced neuronal death and a decrease in the doublecortin positive cells in the dentate gyrus of PI3Kγ(-/-) animals after the induction of SE. Levels of BDNF were significantly increased in the hippocampus of WT and PI3Kγ(-/-) mice, although in the prefrontal cortex, only PI3Kγ(-/-) animals showed significant increase in the levels of this neurotrophic factor. Pilocarpine increased hippocampal microglial immunolabeling in both groups, albeit in the prelimbic, medial and motor regions of the prefrontal cortex this increase was observed only in PI3Kγ(-/-) mice. Regarding the levels of inflammatory mediators, pilocarpine injection increased interleukin (IL) 6 in the hippocampus of WT and PI3Kγ(-/-) animals and in the prefrontal cortex of PI3Kγ(-/-) animals 24h after the stimulus. Levels of TNFα were enhanced in the hippocampus and prefrontal cortex of only PI3Kγ(-/-) mice at this time point. On the other hand, PI3Kγ deletion impaired the increase in IL-10 in the hippocampus induced by pilocarpine. In conclusion, the lack of PI3Kγ revealed a deleterious effect in an animal model of convulsions induced by pilocarpine, suggesting that this enzyme may play a protective role in seizures and pathological outcomes associated with this condition.
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Affiliation(s)
- Isabel Vieira de Assis Lima
- Department of Pharmacology, Universidade Federal de Minas Gerais, Av. Antonio Carlos 6627, 31270-901, Belo Horizonte, Brazil
| | - Alline Cristina Campos
- Department of Internal Medicine, Universidade Federal de Minas Gerais, Av. Antonio Carlos 6627, 31270-901, Belo Horizonte, Brazil
| | - Aline Silva Miranda
- Department of Internal Medicine, Universidade Federal de Minas Gerais, Av. Antonio Carlos 6627, 31270-901, Belo Horizonte, Brazil
| | - Érica Leandro Marciano Vieira
- Department of Internal Medicine, Universidade Federal de Minas Gerais, Av. Antonio Carlos 6627, 31270-901, Belo Horizonte, Brazil
| | - Flávia Amaral-Martins
- Department of Pharmacology, Universidade Federal de Minas Gerais, Av. Antonio Carlos 6627, 31270-901, Belo Horizonte, Brazil
| | - Juliana Priscila Vago
- Department of Clinical and Toxicological Analysis, Universidade Federal de Minas Gerais, Av. Antonio Carlos 6627, 31270-901, Belo Horizonte, Brazil
| | - Rebeca Priscila de Melo Santos
- Department of Pharmacology, Universidade Federal de Minas Gerais, Av. Antonio Carlos 6627, 31270-901, Belo Horizonte, Brazil
| | - Lirlândia Pires Sousa
- Department of Clinical and Toxicological Analysis, Universidade Federal de Minas Gerais, Av. Antonio Carlos 6627, 31270-901, Belo Horizonte, Brazil
| | - Luciene Bruno Vieira
- Department of Pharmacology, Universidade Federal de Minas Gerais, Av. Antonio Carlos 6627, 31270-901, Belo Horizonte, Brazil
| | - Mauro Martins Teixeira
- Department of Biochemistry and Immunology, Universidade Federal de Minas Gerais, Av. Antonio Carlos 6627, 31270-901, Belo Horizonte, Brazil
| | - Bernd L Fiebich
- Department of Psychiatry, University of Freiburg Medical School, Hauptstr. 5, D-79104 Freiburg, Germany
| | - Márcio Flávio Dutra Moraes
- Department of Biophysics and Physiology, Universidade Federal de Minas Gerais, Av. Antonio Carlos 6627, 31270-901, Belo Horizonte, Brazil
| | - Antonio Lucio Teixeira
- Department of Internal Medicine, Universidade Federal de Minas Gerais, Av. Antonio Carlos 6627, 31270-901, Belo Horizonte, Brazil
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22
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Tejada J, Roque AC. Computational models of dentate gyrus with epilepsy-induced morphological alterations in granule cells. Epilepsy Behav 2014; 38:63-70. [PMID: 24613760 DOI: 10.1016/j.yebeh.2014.02.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Revised: 02/05/2014] [Accepted: 02/05/2014] [Indexed: 01/24/2023]
Abstract
Temporal lobe epilepsy provokes a number of different morphological alterations in granule cells of the hippocampus dentate gyrus. These alterations may be associated with the hyperactivity and hypersynchrony found in the epileptic dentate gyrus, and their study requires the use of different kinds of approaches including computational modeling. Conductance-based models of both normal and epilepsy-induced morphologically altered granule cells have been used in the construction of network models of dentate gyrus to study the effects of these alterations on epilepsy. Here, we review these models and discuss their contributions to the understanding of the association between alterations in neuronal morphology and epilepsy in the dentate gyrus.
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Affiliation(s)
- Julian Tejada
- Departamento de Física, FFCLRP, Universidade de Sao Paulo, Ribeirao Preto, SP 14040-901, Brazil; Departamento de Psicologia, DPS, Universidade Federal de Sergipe, SE 49100-000, Brazil.
| | - Antonio C Roque
- Departamento de Física, FFCLRP, Universidade de Sao Paulo, Ribeirao Preto, SP 14040-901, Brazil
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Quantitative Arbor Analytics: Unsupervised Harmonic Co-Clustering of Populations of Brain Cell Arbors Based on L-Measure. Neuroinformatics 2014; 13:47-63. [DOI: 10.1007/s12021-014-9237-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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Tejada J, Garcia-Cairasco N, Roque AC. Combined role of seizure-induced dendritic morphology alterations and spine loss in newborn granule cells with mossy fiber sprouting on the hyperexcitability of a computer model of the dentate gyrus. PLoS Comput Biol 2014; 10:e1003601. [PMID: 24811867 PMCID: PMC4014389 DOI: 10.1371/journal.pcbi.1003601] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Accepted: 03/20/2014] [Indexed: 11/18/2022] Open
Abstract
Temporal lobe epilepsy strongly affects hippocampal dentate gyrus granule cells morphology. These cells exhibit seizure-induced anatomical alterations including mossy fiber sprouting, changes in the apical and basal dendritic tree and suffer substantial dendritic spine loss. The effect of some of these changes on the hyperexcitability of the dentate gyrus has been widely studied. For example, mossy fiber sprouting increases the excitability of the circuit while dendritic spine loss may have the opposite effect. However, the effect of the interplay of these different morphological alterations on the hyperexcitability of the dentate gyrus is still unknown. Here we adapted an existing computational model of the dentate gyrus by replacing the reduced granule cell models with morphologically detailed models coming from three-dimensional reconstructions of mature cells. The model simulates a network with 10% of the mossy fiber sprouting observed in the pilocarpine (PILO) model of epilepsy. Different fractions of the mature granule cell models were replaced by morphologically reconstructed models of newborn dentate granule cells from animals with PILO-induced Status Epilepticus, which have apical dendritic alterations and spine loss, and control animals, which do not have these alterations. This complex arrangement of cells and processes allowed us to study the combined effect of mossy fiber sprouting, altered apical dendritic tree and dendritic spine loss in newborn granule cells on the excitability of the dentate gyrus model. Our simulations suggest that alterations in the apical dendritic tree and dendritic spine loss in newborn granule cells have opposing effects on the excitability of the dentate gyrus after Status Epilepticus. Apical dendritic alterations potentiate the increase of excitability provoked by mossy fiber sprouting while spine loss curtails this increase. Neurogenesis is currently a well known phenomenon in the adult brain, in special in some areas such as the subventricular zone and the dentate gyrus in the hippocampus, in which different endogenous and exogenous factors provoke cell proliferation. In the specific case of the dentate gyrus, granule cells proliferate exhibiting altered morphology after the induction of Status Epilepticus (SE) by pilocarpine (PILO). Several days after the injury the new cells show different morphological alterations, for example, in dendritic spines and branching patterns, as well as with the formation of axonal sprouting. The way in which these new cells are integrated into the hippocampus is still unknown with conflicting data in the literature. Here we used computer simulation to test if the activity of the dentate gyrus is affected by the presence of different proportions of new cells after PILO-induced SE. Our results show that the specific morphological alterations present in the granule cells in rats with PILO-induced SE may be responsible for increasing (mossy fiber sprouting) or decreasing (spine loss) the activity in the network. The imbalance between these effects may be manifest as an epileptiform network behavior.
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Affiliation(s)
- Julian Tejada
- Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brasil
- Departamento de Fisiologia, Faculdade de Medicina de Ribeirão Preto, Ribeirão Preto, São Paulo, Brasil
- * E-mail:
| | - Norberto Garcia-Cairasco
- Departamento de Fisiologia, Faculdade de Medicina de Ribeirão Preto, Ribeirão Preto, São Paulo, Brasil
| | - Antonio C. Roque
- Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brasil
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Khalil OS, Pisar M, Forrest CM, Vincenten MCJ, Darlington LG, Stone TW. Prenatal inhibition of the kynurenine pathway leads to structural changes in the hippocampus of adult rat offspring. Eur J Neurosci 2014; 39:1558-71. [PMID: 24646396 PMCID: PMC4368408 DOI: 10.1111/ejn.12535] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 01/28/2014] [Accepted: 01/30/2014] [Indexed: 12/13/2022]
Abstract
Glutamate receptors for N-methyl-d-aspartate (NMDA) are involved in early brain development. The kynurenine pathway of tryptophan metabolism includes the NMDA receptor agonist quinolinic acid and the antagonist kynurenic acid. We now report that prenatal inhibition of the pathway in rats with 3,4-dimethoxy-N-[4-(3-nitrophenyl)thiazol-2-yl]benzenesulphonamide (Ro61-8048) produces marked changes in hippocampal neuron morphology, spine density and the immunocytochemical localisation of developmental proteins in the offspring at postnatal day 60. Golgi–Cox silver staining revealed decreased overall numbers and lengths of CA1 basal dendrites and secondary basal dendrites, together with fewer basal dendritic spines and less overall dendritic complexity in the basal arbour. Fewer dendrites and less complexity were also noted in the dentate gyrus granule cells. More neurons containing the nuclear marker NeuN and the developmental protein sonic hedgehog were detected in the CA1 region and dentate gyrus. Staining for doublecortin revealed fewer newly generated granule cells bearing extended dendritic processes. The number of neuron terminals staining for vesicular glutamate transporter (VGLUT)-1 and VGLUT-2 was increased by Ro61-8048, with no change in expression of vesicular GABA transporter or its co-localisation with vesicle-associated membrane protein-1. These data support the view that constitutive kynurenine metabolism normally plays a role in early embryonic brain development, and that interfering with it has profound consequences for neuronal structure and morphology, lasting into adulthood.
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Affiliation(s)
- Omari S Khalil
- Institute of Neuroscience and Psychology, West Medical Building, University of Glasgow, Glasgow, G12 8QQ, UK
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Kim BK, Shin MS, Kim CJ, Baek SB, Ko YC, Kim YP. Treadmill exercise improves short-term memory by enhancing neurogenesis in amyloid beta-induced Alzheimer disease rats. J Exerc Rehabil 2014; 10:2-8. [PMID: 24678498 PMCID: PMC3952831 DOI: 10.12965/jer.140086] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Revised: 01/28/2014] [Accepted: 02/06/2014] [Indexed: 12/31/2022] Open
Abstract
Alzheimer's disease is one of the most devastating neurodegenerative disorders, and this disease is characterized by severe memory impairment and decline of cognition. Hippocampal neurons are vulnerable to injury induced by Alzheimer's disease. Physical exercise is known to promote cell survival and functional recovery after brain injuries. In the present study, we investigated the effects of treadmill exercise on short-term memory in relation with neurogenesis in the rats with amyloid β25-35 (Aβ25-35)-induced Alzheimer's disease. The rat model of Alzheimer's disease was induced by the intracerebroventricular (ICV) injection of Aβ25-35, using a stereotaxic instrument. The rats in the exercise group were forced to run on a treadmill for 30 min once daily for 4 consecutive weeks, starting 2 days after Aβ25-35 injection. Presently, short-term memory was deteriorated and apical dendritic length in the hippocampus was shortened in the hippocampus by Aβ25-35 injection. In contrast, treadmill exercise alleviated memory impairment and increased apical dendritic length in the Aβ25-35-injected rats. Neurogenesis and brain-derived neurotorphic factor (BDNF) and tyrosine kinase B (trkB) in the hippocampal dentate gyrus were decreased by Aβ25-35 injection. Treadmill exercise increased neurogenesis and expressions of BDNF and trkB expressions. The present study shows that treadmill exercise may provide therapeutic value for the alleviating symptoms of Alzheimer's disease.
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Affiliation(s)
- Bo-Kyun Kim
- Department of Physiology, College of Medicine, Kyung Hee University, Seoul, Korea
| | - Mal-Soon Shin
- Department of Physiology, College of Medicine, Kyung Hee University, Seoul, Korea
| | - Chang-Ju Kim
- Department of Physiology, College of Medicine, Kyung Hee University, Seoul, Korea
| | - Sang-Bin Baek
- Department of Psychiatry, Gangneung Asan Hospital, Ulsan University, Gangneung, Korea
| | - Yeong-Chan Ko
- Faculty of Exercise & Sports Science, Jeju National University, Jeju, Korea
| | - Young-Pyo Kim
- Faculty of Exercise & Sports Science, Jeju National University, Jeju, Korea
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Kandratavicius L, Rosa-Neto P, Monteiro MR, Guiot MC, Assirati JA, Carlotti CG, Kobayashi E, Leite JP. Distinct increased metabotropic glutamate receptor type 5 (mGluR5) in temporal lobe epilepsy with and without hippocampal sclerosis. Hippocampus 2013; 23:1212-30. [PMID: 23804486 PMCID: PMC4165311 DOI: 10.1002/hipo.22160] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/31/2013] [Indexed: 12/04/2022]
Abstract
Metabotropic glutamate receptor type 5 (mGluR5) upregulation in temporal lobe epilepsy (TLE) and the correlation of its expression with features of hippocampal sclerosis (HS) remains unclear. Here we characterized mGluR5 immunoreactivity in hippocampus, entorhinal cortex (EC), and subiculum of TLE specimens with confirmed HS, with neocortical TLE (non-HS) and necropsy controls. We correlated mGluR5 immunoreactivity with neuronal density, mossy fiber sprouting, astrogliosis (GFAP), and dendritic alterations (MAP2). TLE specimens showed increased mGluR5 expression, which was most pronounced in the EC, subiculum, CA2, and dentate gyrus outer molecular layer. Increased mGluR5 expression was seen in hippocampal head and body segments and was independent of neuronal density, astrogliosis, or dendritic alterations. Positive correlation between mGluR5 expression with mossy fiber sprouting and with MAP2 in CA3 and CA1 was found only in HS specimens. Negative correlation between mGluR5 expression with seizure frequency and epilepsy duration was found only in non-HS cases. Specimens from HS patients without previous history of febrile seizure (FS) showed higher mGluR5 and MAP2 expression in CA2. Our study suggests that mGluR5 upregulation is part of a repertoire of post-synaptic adaptations that might control overexcitation and excessive glutamate release rather than a dysfunction that leads to seizure facilitation. That would explain why non-HS cases, on which seizures are likely to originate outside the hippocampal formation, also exhibit upregulated mGluR5. On the other hand, lower mGluR5 expression was related to increased seizure frequency. In addition to its role in hyperexcitability, mGluR5 upregulation could play a role in counterbalance mechanisms along the hyperexcitable circuitry uniquely altered in sclerotic hippocampal formation. Inefficient post-synaptic compensatory morphological (dendritic branching) and glutamatergic (mGluR5 expression) mechanisms in CA2 subfield could potentially underlie the association of FS with HS and TLE. © 2013 Wiley Periodicals, Inc.
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Affiliation(s)
- Ludmyla Kandratavicius
- Department of Neurosciences and Behavior, Ribeirao Preto Medical School, University of Sao PauloBrazil
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill UniversityMontreal, Canada
| | - Pedro Rosa-Neto
- Translational Neuroimaging Laboratory, Department of Neurology and Neurosurgery, Douglas Research Institute, McGill UniversityMontreal, Canada
| | - Mariana Raquel Monteiro
- Department of Neurosciences and Behavior, Ribeirao Preto Medical School, University of Sao PauloBrazil
| | - Marie-Christine Guiot
- Department of Pathology, Montreal Neurological Institute, McGill UniversityMontreal, Canada
| | | | | | - Eliane Kobayashi
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill UniversityMontreal, Canada
| | - Joao Pereira Leite
- Department of Neurosciences and Behavior, Ribeirao Preto Medical School, University of Sao PauloBrazil
- *Correspondence to: Joao Pereira Leite, Ribeirao Preto Medical School, Department of Neurosciences and Behavior, University of Sao Paulo, Av Bandeirantes 3900, 14049-900, Ribeirao Preto, SP, Brazil. E-mail:
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Tejada J, Costa KM, Bertti P, Garcia-Cairasco N. The epilepsies: complex challenges needing complex solutions. Epilepsy Behav 2013; 26:212-28. [PMID: 23146364 DOI: 10.1016/j.yebeh.2012.09.029] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Accepted: 09/16/2012] [Indexed: 12/19/2022]
Abstract
It is widely accepted that epilepsies are complex syndromes due to their multi-factorial origins and manifestations. Different mathematical and computational descriptions use appropriate methods to address nonlinear relationships, chaotic behaviors and emergent properties. These theoretical approaches can be divided into two major categories: descriptive, such as flowcharts, graphs and other statistical analyses, and explicative, which include both realistic and abstract models. Although these modeling tools have brought great advances, a common framework to guide their design, implementation and evaluation, with the goal of future integration, is still needed. In the current review, we discuss two examples of complexity analysis that can be performed with epilepsy data: behavioral sequences of temporal lobe seizures and alterations in an experimental cellular model. We also highlight the importance of the creation of model repositories for the epileptology field and encourage the development of mathematical descriptions of complex systems, together with more accurate simulation techniques.
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Affiliation(s)
- Julián Tejada
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Brazil
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29
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Paus M, Kohl Z, Ben Abdallah NMB, Galter D, Gillardon F, Winkler J. Enhanced dendritogenesis and axogenesis in hippocampal neuroblasts of LRRK2 knockout mice. Brain Res 2012; 1497:85-100. [PMID: 23270607 DOI: 10.1016/j.brainres.2012.12.024] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Revised: 12/02/2012] [Accepted: 12/13/2012] [Indexed: 11/28/2022]
Abstract
Adult neurogenesis, the formation of new neurons in the mammalian forebrain, is one important mechanism maintaining lifelong neuronal plasticity. The generation and maturation of adult neural stem and progenitor cells is impaired in models of neurodegenerative diseases, in particular Parkinson's disease (PD). Monogenetic forms of PD were identified and associated with several genes including the leucine-rich-repeat kinase 2 (LRRK2). Some of the underlying mechanisms in neurodegenerative diseases are closely linked to neuronal plasticity, and induce changes in adult neurogenesis, neuritic maintenance, synaptic transmission, and neural connectivity. We investigated adult neurogenesis and neuritic development of newly formed neurons in the hippocampal dentate gyrus of LRRK2 knockout mice. Proliferation and survival of newly generated cells were unchanged. However, the expression profile of maturation markers in surviving newly generated cells was altered. While immature neuronal phenotypes were significantly increased, the mature neuronal phenotype of surviving cells remained unchanged. Importantly, the absolute number of immature doublecortin positive neuroblasts was significantly increased in the hippocampus of LRRK2 knockout mice. These neuroblasts presented extended dendritic length with a more complex arborization. Furthermore, LRRK2 deletion resulted in an increased volume of the axonal mossy fiber bundle projecting from dentate granule cells to CA3 pyramidal neurons. Our findings suggest that LRRK2 influences neurogenesis and particularly neuronal morphogenesis. As neurogenesis and the pre-/post- synaptic compartments are significantly altered in PD, our data advance LRRK2 as a potent candidate in addressing neuroregenerative processes.
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Affiliation(s)
- Marie Paus
- Department of Molecular Neurology, University Hospital Erlangen, Erlangen, Germany.
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30
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Tejada J, Garcia-Cairasco N, Roque AC. Role of morphological changes in newly born granule cells of hippocampus after status epilepticus induced by pilocarpine in hyperexcitability. BMC Neurosci 2012. [PMCID: PMC3403330 DOI: 10.1186/1471-2202-13-s1-p56] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Tejada J, Arisi GM, García-Cairasco N, Roque AC. Morphological alterations in newly born dentate gyrus granule cells that emerge after status epilepticus contribute to make them less excitable. PLoS One 2012; 7:e40726. [PMID: 22811762 PMCID: PMC3394725 DOI: 10.1371/journal.pone.0040726] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Accepted: 06/13/2012] [Indexed: 11/18/2022] Open
Abstract
Computer simulations of external current stimulations of dentate gyrus granule cells of rats with Status Epilepticus induced by pilocarpine and control rats were used to evaluate whether morphological differences alone between these cells have an impact on their electrophysiological behavior. The cell models were constructed using morphological information from tridimensional reconstructions with Neurolucida software. To evaluate the effect of morphology differences alone, ion channel conductances, densities and distributions over the dendritic trees of dentate gyrus granule cells were the same for all models. External simulated currents were injected in randomly chosen dendrites belonging to one of three different areas of dentate gyrus granule cell molecular layer: inner molecular layer, medial molecular layer and outer molecular layer. Somatic membrane potentials were recorded to determine firing frequencies and inter-spike intervals. The results show that morphologically altered granule cells from pilocarpine-induced epileptic rats are less excitable than control cells, especially when they are stimulated in the inner molecular layer, which is the target area for mossy fibers that sprout after pilocarpine-induced cell degeneration. This suggests that morphological alterations may act as a protective mechanism to allow dentate gyrus granule cells to cope with the increase of stimulation caused by mossy fiber sprouting.
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Affiliation(s)
- Julián Tejada
- Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
- Departamento de Fisiologia, Faculdade de Medicina de Ribeirão Preto, Ribeirão Preto, São Paulo, Brazil
| | - Gabriel M. Arisi
- Departamento de Fisiologia, Faculdade de Medicina de Ribeirão Preto, Ribeirão Preto, São Paulo, Brazil
| | - Norberto García-Cairasco
- Departamento de Fisiologia, Faculdade de Medicina de Ribeirão Preto, Ribeirão Preto, São Paulo, Brazil
- * E-mail: (AR); (NG-C)
| | - Antonio C. Roque
- Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
- * E-mail: (AR); (NG-C)
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32
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Petrik D, Jiang Y, Birnbaum SG, Powell CM, Kim MS, Hsieh J, Eisch AJ. Functional and mechanistic exploration of an adult neurogenesis-promoting small molecule. FASEB J 2012; 26:3148-62. [PMID: 22542682 DOI: 10.1096/fj.11-201426] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Adult neurogenesis occurs throughout life in the mammalian hippocampus and is essential for memory and mood control. There is significant interest in identifying ways to promote neurogenesis and ensure maintenance of these hippocampal functions. Previous work with a synthetic small molecule, isoxazole 9 (Isx-9), highlighted its neuronal-differentiating properties in vitro. However, the ability of Isx-9 to drive neurogenesis in vivo or improve hippocampal function was unknown. Here we show that Isx-9 promotes neurogenesis in vivo, enhancing the proliferation and differentiation of hippocampal subgranular zone (SGZ) neuroblasts, and the dendritic arborization of adult-generated dentate gyrus neurons. Isx-9 also improves hippocampal function, enhancing memory in the Morris water maze. Notably, Isx-9 enhances neurogenesis and memory without detectable increases in cellular or animal activity or vascularization. Molecular exploration of Isx-9-induced regulation of neurogenesis (via FACS and microarray of SGZ stem and progenitor cells) suggested the involvement of the myocyte-enhancer family of proteins (Mef2). Indeed, transgenic-mediated inducible knockout of all brain-enriched Mef2 isoforms (Mef2a/c/d) specifically from neural stem cells and their progeny confirmed Mef2's requirement for Isx-9-induced increase in hippocampal neurogenesis. Thus, Isx-9 enhances hippocampal neurogenesis and memory in vivo, and its effects are reliant on Mef2, revealing a novel cell-intrinsic molecular pathway regulating adult neurogenesis.
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Affiliation(s)
- David Petrik
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9070, USA
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Santos VR, de Castro OW, Pun RYK, Hester MS, Murphy BL, Loepke AW, Garcia-Cairasco N, Danzer SC. Contributions of mature granule cells to structural plasticity in temporal lobe epilepsy. Neuroscience 2011; 197:348-57. [PMID: 21963349 DOI: 10.1016/j.neuroscience.2011.09.034] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2011] [Revised: 09/13/2011] [Accepted: 09/13/2011] [Indexed: 01/04/2023]
Abstract
During the development of epilepsy in adult animals, newly generated granule cells integrate abnormally into the hippocampus. These new cells migrate to ectopic locations in the hilus, develop aberrant basal dendrites, contribute to mossy fiber sprouting, and exhibit changes in apical dendrite structure and dendritic spine number. Mature granule cells do not appear to exhibit migration defects, basal dendrites, and mossy fiber sprouting, but whether they exhibit apical dendrite abnormalities or spine changes is not known. To address these questions, we examined the apical dendritic structure of bromodeoxyuridine (Brdu)-birthdated, green fluorescent protein (GFP)-expressing granule cells born 2 months before pilocarpine-induced status epilepticus. In contrast to immature granule cells, exposing mature granule cells to status epilepticus did not significantly disrupt the branching structure of their apical dendrites. Mature granule cells did, however, exhibit significant reductions in spine density and spine number relative to age-matched cells from control animals. These data demonstrate that while mature granule cells are resistant to developing the gross structural abnormalities exhibited by younger granule cells, they show similar plastic rearrangement of their dendritic spines.
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Affiliation(s)
- V R Santos
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
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34
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Abstract
The functional impact of adult-generated granule cells in the epileptic brain is unclear, with data supporting both protective and maladaptive roles. These conflicting findings could be explained if new granule cells integrate heterogeneously, with some cells taking neutral or adaptive roles and others contributing to recurrent circuitry supporting seizures. Here, we tested this hypothesis by completing detailed morphological characterizations of age- and experience-defined cohorts of adult-generated granule cells from transgenic mice. The majority of newborn cells exposed to an epileptogenic insult exhibited reductions in dendritic spine number, suggesting reduced excitatory input to these cells. A significant subset, however, exhibited higher spine numbers. These latter cells tended to have enlarged cell bodies, long basal dendrites, or both. Moreover, cells with basal dendrites received significantly more recurrent mossy fiber input through their apical dendrites, indicating that these cells are robustly integrated into the pathological circuitry of the epileptic brain. These data imply that newborn cells play complex--and potentially conflicting--roles in epilepsy.
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Gitaí DLG, Fachin AL, Mello SS, Elias CF, Bittencourt JC, Leite JP, Passos GADS, Garcia-Cairasco N, Paçó-Larson ML. The non-coding RNA BC1 is down-regulated in the hippocampus of Wistar Audiogenic Rat (WAR) strain after audiogenic kindling. Brain Res 2010; 1367:114-21. [PMID: 20974111 DOI: 10.1016/j.brainres.2010.10.069] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2010] [Revised: 09/21/2010] [Accepted: 10/17/2010] [Indexed: 01/08/2023]
Abstract
The aim of this study was to identify molecular pathways involved in audiogenic seizures in the epilepsy-prone Wistar Audiogenic Rat (WAR). For this, we used a suppression-subtractive hybridization (SSH) library from the hippocampus of WARs coupled to microarray comparative gene expression analysis, followed by Northern blot validation of individual genes. We discovered that the levels of the non-protein coding (npc) RNA BC1 were significantly reduced in the hippocampus of WARs submitted to repeated audiogenic seizures (audiogenic kindling) when compared to Wistar resistant rats and to both naive WARs and Wistars. By quantitative in situ hybridization, we verified lower levels of BC1 RNA in the GD-hilus and significant signal ratio reduction in the stratum radiatum and stratum pyramidale of hippocampal CA3 subfield of audiogenic kindled animals. Functional results recently obtained in a BC1⁻/⁻ mouse model and our current data are supportive of a potential disruption in signaling pathways, upstream of BC1, associated with the seizure susceptibility of WARs.
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Affiliation(s)
- Daniel Leite Goes Gitaí
- Department of Cellular and Molecular Biology, Ribeirão Preto School of Medicine, University of São Paulo, Brazil
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Whole transcriptome analysis of the hippocampus: toward a molecular portrait of epileptogenesis. BMC Genomics 2010; 11:230. [PMID: 20377889 PMCID: PMC2859406 DOI: 10.1186/1471-2164-11-230] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2009] [Accepted: 04/08/2010] [Indexed: 01/12/2023] Open
Abstract
Background Uncovering the molecular mechanisms involved in epileptogenesis is critical to better understand the physiopathology of epilepsies and to help develop new therapeutic strategies for this prevalent and severe neurological condition that affects millions of people worldwide. Results Changes in the transcriptome of hippocampal cells from rats subjected to the pilocarpine model of epilepsy were evaluated by microarrays covering 34,000 transcripts representing all annotated rat genes to date. Using such genome-wide approach, differential expression of nearly 1,400 genes was detected during the course of epileptogenesis, from the early events post status epilepticus (SE) to the onset of recurrent spontaneous seizures. Most of these genes are novel and displayed an up-regulation after SE. Noteworthy, a group of 128 genes was found consistently hyper-expressed throughout epileptogenesis, indicating stable modulation of the p38MAPK, Jak-STAT, PI3K, and mTOR signaling pathways. In particular, up-regulation of genes from the TGF-beta and IGF-1 signaling pathways, with opposite effects on neurogenesis, correlate with the physiopathological changes reported in humans. Conclusions A consistent regulation of genes functioning in intracellular signal transduction regulating neurogenesis have been identified during epileptogenesis, some of which with parallel expression patterns reported in patients with epilepsy, strengthening the link between these processes and development of epilepsy. These findings reveal dynamic molecular changes occurring in the hippocampus that may serve as a starting point for designing alternative therapeutic strategies to prevent the development of epilepsy after acquired brain insults.
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Hattiangady B, Shetty AK. Decreased neuronal differentiation of newly generated cells underlies reduced hippocampal neurogenesis in chronic temporal lobe epilepsy. Hippocampus 2010; 20:97-112. [PMID: 19309040 DOI: 10.1002/hipo.20594] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Hippocampal neurogenesis declines substantially in chronic temporal lobe epilepsy (TLE). However, it is unclear whether this decline is linked to altered production of new cells and/or diminished survival and neuronal fate-choice decision of newly born cells. We quantified different components of hippocampal neurogenesis in rats exhibiting chronic TLE. Through intraperitoneal administration of 5'-bromodeoxyuridine (BrdU) for 12 days, we measured numbers of newly born cells in the subgranular zone-granule cell layer (SGZ-GCL) at 24 h and 2.5 months post-BrdU administration. Furthermore, the differentiation of newly added cells into neurons and glia was quantified via dual immunofluorescence for BrdU and various markers of neurons and glia. Addition of new cells to the SGZ-GCL over 12 days was comparable between the chronically epileptic hippocampus and the age-matched intact hippocampus. Furthermore, comparison of BrdU+ cells measured at 24 h and 2.5 months post-BrdU administration revealed similar survival of newly born cells between the two groups. However, only 4-5% of newly born cells (i.e., BrdU+ cells) differentiated into neurons in the chronically epileptic hippocampus, in comparison to 73-80% of such cells exhibiting neuronal differentiation in the intact hippocampus. Moreover, differentiation of newly born cells into S-100beta+ astrocytes or NG2+ oligodendrocyte progenitors increased to approximately 79% in the chronically epileptic hippocampus from approximately 25% observed in the intact hippocampus. Interestingly, the extent of proliferation of astrocytes and microglia (identified through Ki-67 and S-100beta and Ki-67 and OX-42 dual immunofluorescence) in the SGZ-GCL was similar between the chronically epileptic hippocampus and the age-matched intact hippocampus, implying that the proliferation of neural stem/progenitor cells in the SGZ-GCL of the chronically epileptic hippocampus was not obscured by an increased division of glia. Thus, severely diminished DG neurogenesis in chronic TLE is not associated with either decreased production of new cells or reduced survival of newly born cells in the SGZ-GCL. Rather, it is linked to a dramatic decline in the neuronal fate-choice decision of newly generated cells. Overall, the differentiation of newly born cells turns mainly into glia with chronic TLE from predominantly neuronal differentiation seen in control conditions.
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Affiliation(s)
- Bharathi Hattiangady
- Department of Surgery (Neurosurgery), Duke University Medical Center, Durham, North Carolina 27710, USA
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Down-regulation of APLP1 mRNA expression in hippocampus of pilocarpine-induced epileptic rats. Neurosci Bull 2009; 25:109-14. [PMID: 19448684 DOI: 10.1007/s12264-009-1229-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
OBJECTIVE To investigate the expression of amyloid beta precursor-like protein 1(APLP1) gene on the transcription level in hippocampus of pilocarpine-induced epileptic rats. METHODS Epileptic rats were developed by LiC1 (3 mmol/kg, i.p.) approximately 20 h prior to pilocarpine (30 mg/kg, i.p.) administration. The 3' end partial sequence of rat APLP1 gene was cloned, and the expression levels of APLP1 mRNA in hippocampus of epileptic rats at 6 h, 30 h, 7 d and 15 d were determined by semi-quantitative RT-PCR. RESULTS The 3'end partial sequence of rat APLP1 gene shared a 97% homology with that of mice, and 90% with that of human. The APLP1 amino acid sequence of rat was identical with that of mouse, but was different from that of human in 3 residues. Moreover, pilocarpine induced a significant down-regulation of APLP1 mRNA expression at 6 h after epilepsy initiation (P< 0.05), and at 30 h, this down-regulation became more dramatic (P< 0.01), which lasted till day 15 (P< 0.01). CONCLUSION The 3' end of APLP1 gene is highly conserved, and APLP1 mRNA expression is kept at low level in hippocampus of pilocarpine-induced epileptic rats.
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Puzzling challenges in contemporary neuroscience: insights from complexity and emergence in epileptogenic circuits. Epilepsy Behav 2009; 14 Suppl 1:54-63. [PMID: 18835370 DOI: 10.1016/j.yebeh.2008.09.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2008] [Revised: 09/02/2008] [Accepted: 09/03/2008] [Indexed: 11/24/2022]
Abstract
The brain is a complex system that, in the normal condition, has emergent properties like those associated with activity-dependent plasticity in learning and memory, and in pathological situations, manifests abnormal long-term phenomena like the epilepsies. Data from our laboratory and from the literature were classified qualitatively as sources of complexity and emergent properties from behavior to electrophysiological, cellular, molecular, and computational levels. We used such models as brainstem-dependent acute audiogenic seizures and forebrain-dependent kindled audiogenic seizures. Additionally we used chemical or electrical experimental models of temporal lobe epilepsy that induce status epilepticus with behavioral, anatomical, and molecular sequelae such as spontaneous recurrent seizures and long-term plastic changes. Current computational neuroscience tools will help the interpretation, storage, and sharing of the exponential growth of information derived from those studies. These strategies are considered solutions to deal with the complexity of brain pathologies such as the epilepsies.
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Kuruba R, Hattiangady B, Shetty AK. Hippocampal neurogenesis and neural stem cells in temporal lobe epilepsy. Epilepsy Behav 2009; 14 Suppl 1:65-73. [PMID: 18796338 PMCID: PMC2654382 DOI: 10.1016/j.yebeh.2008.08.020] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2008] [Revised: 08/28/2008] [Accepted: 08/29/2008] [Indexed: 12/12/2022]
Abstract
Virtually all mammals, including humans, exhibit neurogenesis throughout life in the hippocampus, a learning and memory center in the brain. Numerous studies in animal models imply that hippocampal neurogenesis is important for functions such as learning, memory, and mood. Interestingly, hippocampal neurogenesis is very sensitive to physiological and pathological stimuli. Certain pathological stimuli such as seizures alter both the amount and the pattern of neurogenesis, though the overall effect depends on the type of seizures. Acute seizures are classically associated with augmentation of neurogenesis and migration of newly born neurons into ectopic regions such as the hilus and the molecular layer of the dentate gyrus. Additional studies suggest that abnormally migrated newly born neurons play a role in the occurrence of epileptogenic hippocampal circuitry characteristically seen after acute seizures, status epilepticus, or head injury. Recurrent spontaneous seizures such as those typically observed in chronic temporal lobe epilepsy are associated with substantially reduced neurogenesis, which, interestingly, coexists with learning and memory impairments and depression. In this review, we discuss both the extent and the potential implications of abnormal hippocampal neurogenesis induced by acute seizures as well as recurrent spontaneous seizures. We also discuss the consequences of chronic spontaneous seizures on differentiation of neural stem cell progeny in the hippocampus and strategies that are potentially useful for normalizing neurogenesis in chronic temporal lobe epilepsy.
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Affiliation(s)
- Ramkumar Kuruba
- Department of Surgery (Neurosurgery) Duke University Medical Center, Durham, NC 27710,Medical Research and Surgery Services, Veterans Affairs Medical Center, Durham, NC 27705
| | - Bharathi Hattiangady
- Department of Surgery (Neurosurgery) Duke University Medical Center, Durham, NC 27710,Medical Research and Surgery Services, Veterans Affairs Medical Center, Durham, NC 27705
| | - Ashok K. Shetty
- Department of Surgery (Neurosurgery) Duke University Medical Center, Durham, NC 27710,Medical Research and Surgery Services, Veterans Affairs Medical Center, Durham, NC 27705,Correspondence should be addressed to: Ashok K. Shetty, M.Sc., Ph.D., Professor, Division of Neurosurgery, Box 3807, Duke University Medical Center, Durham NC 27710, Phone: 919-286-0411, Ext. 7096, E-mail:
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Garcia-Cairasco N. Learning about brain physiology and complexity from the study of the epilepsies. Braz J Med Biol Res 2009; 42:76-86. [DOI: 10.1590/s0100-879x2009000100012] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2008] [Accepted: 12/16/2008] [Indexed: 01/26/2023] Open
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Zhao CS, Overstreet-Wadiche L. Integration of adult generated neurons during epileptogenesis. Epilepsia 2008; 49 Suppl 5:3-12. [DOI: 10.1111/j.1528-1167.2008.01632.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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