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van Campen JS, Hessel EVS, Bohmbach K, Rizzi G, Lucassen PJ, Lakshmi Turimella S, Umeoka EHL, Meerhoff GF, Braun KPJ, de Graan PNE, Joëls M. Stress and Corticosteroids Aggravate Morphological Changes in the Dentate Gyrus after Early-Life Experimental Febrile Seizures in Mice. Front Endocrinol (Lausanne) 2018; 9:3. [PMID: 29434572 PMCID: PMC5790804 DOI: 10.3389/fendo.2018.00003] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2017] [Accepted: 01/05/2018] [Indexed: 12/17/2022] Open
Abstract
Stress is the most frequently self-reported seizure precipitant in patients with epilepsy. Moreover, a relation between ear stress and epilepsy has been suggested. Although ear stress and stress hormones are known to influence seizure threshold in rodents, effects on the development of epilepsy (epileptogenesis) are still unclear. Therefore, we studied the consequences of ear corticosteroid exposure for epileptogenesis, under highly controlled conditions in an animal model. Experimental febrile seizures (eFS) were elicited in 10-day-old mice by warm-air induced hyperthermia, while a control group was exposed to a normothermic condition. In the following 2 weeks, mice received either seven corticosterone or vehicle injections or were left undisturbed. Specific measures indicative for epileptogenesis were examined at 25 days of age and compared with vehicle injected or untreated mice. We examined structural [neurogenesis, dendritic morphology, and mossy fiber sprouting (MFS)] and functional (glutamatergic postsynaptic currents and long-term potentiation) plasticity in the dentate gyrus (DG). We found that differences in DG morphology induced by eFS were aggravated by repetitive (mildly stressful) vehicle injections and corticosterone exposure. In the injected groups, eFS were associated with decreases in neurogenesis, and increases in cell proliferation, dendritic length, and spine density. No group differences were found in MFS. Despite these changes in DG morphology, no effects of eFS were found on functional plasticity. We conclude that corticosterone exposure during early epileptogenesis elicited by eFS aggravates morphological, but not functional, changes in the DG, which partly supports the hypothesis that ear stress stimulates epileptogenesis.
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Affiliation(s)
- Jolien S. van Campen
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, Netherlands
- Department of Child Neurology, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, Netherlands
| | - Ellen V. S. Hessel
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, Netherlands
| | - Kirsten Bohmbach
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, Netherlands
| | - Giorgio Rizzi
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, Netherlands
| | - Paul J. Lucassen
- Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, Amsterdam, Netherlands
| | - Sada Lakshmi Turimella
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, Netherlands
| | - Eduardo H. L. Umeoka
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, Netherlands
- Neursocience and Behavioral Sciences Department, Ribeirão Preto School of Medicine, University of São Paulo, Ribeirão Preto, Brazil
| | - Gideon F. Meerhoff
- Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, Amsterdam, Netherlands
| | - Kees P. J. Braun
- Department of Child Neurology, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, Netherlands
| | - Pierre N. E. de Graan
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, Netherlands
| | - Marian Joëls
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, Netherlands
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Hessel EVS, van Lith HA, Wolterink-Donselaar IG, de Wit M, Groot Koerkamp MJA, Holstege FCP, Kas MJH, Fernandes C, de Graan PNE. Mapping of aFEB3homologous febrile seizure locus on mouse chromosome 2 containing candidate genesScn1aandScn3a. Eur J Neurosci 2016; 44:2950-2957. [DOI: 10.1111/ejn.13420] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Revised: 07/10/2016] [Accepted: 08/09/2016] [Indexed: 01/05/2023]
Affiliation(s)
- Ellen V. S. Hessel
- Brain Center Rudolf Magnus; Department of Translational Neuroscience; University Medical Center Utrecht; Universiteitsweg 100 3584 CG Utrecht The Netherlands
| | - Hein A. van Lith
- Division of Animal Welfare & Laboratory Animal Science; Department of Animals in Science & Society; Faculty of Veterinary Medicine and Brain Center Rudolf Magnus; Utrecht University; Utrecht The Netherlands
| | - Inge G. Wolterink-Donselaar
- Brain Center Rudolf Magnus; Department of Translational Neuroscience; University Medical Center Utrecht; Universiteitsweg 100 3584 CG Utrecht The Netherlands
| | - Marina de Wit
- Brain Center Rudolf Magnus; Department of Translational Neuroscience; University Medical Center Utrecht; Universiteitsweg 100 3584 CG Utrecht The Netherlands
| | | | - Frank C. P. Holstege
- Department of Molecular Cancer Research; University Medical Center Utrecht; Utrecht The Netherlands
| | - Martien J. H. Kas
- Brain Center Rudolf Magnus; Department of Translational Neuroscience; University Medical Center Utrecht; Universiteitsweg 100 3584 CG Utrecht The Netherlands
- Groningen Institute for Evolutionary Life Sciences; University of Groningen; Groningen The Netherlands
| | - Cathy Fernandes
- Social, Genetic & Developmental Psychiatry Centre; Institute of Psychiatry; Psychology and Neuroscience; King's College London; London UK
| | - Pierre N. E. de Graan
- Brain Center Rudolf Magnus; Department of Translational Neuroscience; University Medical Center Utrecht; Universiteitsweg 100 3584 CG Utrecht The Netherlands
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Jongbloets BC, van Gassen KLI, Kan AA, Olde Engberink AHO, de Wit M, Wolterink-Donselaar IG, Groot Koerkamp MJA, van Nieuwenhuizen O, Holstege FCP, de Graan PNE. Expression Profiling after Prolonged Experimental Febrile Seizures in Mice Suggests Structural Remodeling in the Hippocampus. PLoS One 2015; 10:e0145247. [PMID: 26684451 PMCID: PMC4684321 DOI: 10.1371/journal.pone.0145247] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 11/30/2015] [Indexed: 12/11/2022] Open
Abstract
Febrile seizures are the most prevalent type of seizures among children up to 5 years of age (2–4% of Western-European children). Complex febrile seizures are associated with an increased risk to develop temporal lobe epilepsy. To investigate short- and long-term effects of experimental febrile seizures (eFS), we induced eFS in highly febrile convulsion-susceptible C57BL/6J mice at post-natal day 10 by exposure to hyperthermia (HT) and compared them to normotherm-exposed (NT) mice. We detected structural re-organization in the hippocampus 14 days after eFS. To identify molecular candidates, which entrain this structural re-organization, we investigated temporal changes in mRNA expression profiles eFS 1 hour to 56 days after eFS. We identified 931 regulated genes and profiled several candidates using in situ hybridization and histology at 3 and 14 days after eFS. This is the first study to report genome-wide transcriptome analysis after eFS in mice. We identify temporal regulation of multiple processes, such as stress-, immune- and inflammatory responses, glia activation, glutamate-glutamine cycle and myelination. Identification of the short- and long-term changes after eFS is important to elucidate the mechanisms contributing to epileptogenesis.
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Affiliation(s)
- Bart C Jongbloets
- Brain Center Rudolf Magnus, Department of Translational Neuroscience, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Koen L I van Gassen
- Brain Center Rudolf Magnus, Department of Translational Neuroscience, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Anne A Kan
- Brain Center Rudolf Magnus, Department of Translational Neuroscience, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Anneke H O Olde Engberink
- Brain Center Rudolf Magnus, Department of Translational Neuroscience, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Marina de Wit
- Brain Center Rudolf Magnus, Department of Translational Neuroscience, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Inge G Wolterink-Donselaar
- Brain Center Rudolf Magnus, Department of Translational Neuroscience, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Marian J A Groot Koerkamp
- Molecular Cancer Research, Division Biomedical Genetics, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Onno van Nieuwenhuizen
- Brain Center Rudolf Magnus, Department of Pediatric Neurology, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Frank C P Holstege
- Molecular Cancer Research, Division Biomedical Genetics, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Pierre N E de Graan
- Brain Center Rudolf Magnus, Department of Translational Neuroscience, University Medical Center Utrecht, Utrecht, the Netherlands
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van der Hel WS, Hessel EVS, Bos IWM, Mulder SD, Verlinde SAMW, van Eijsden P, de Graan PNE. Persistent reduction of hippocampal glutamine synthetase expression after status epilepticus in immature rats. Eur J Neurosci 2014; 40:3711-9. [PMID: 25350774 DOI: 10.1111/ejn.12756] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Revised: 09/13/2014] [Accepted: 09/22/2014] [Indexed: 01/16/2023]
Abstract
Mesiotemporal sclerosis (MTS), the most frequent form of drug-resistant temporal lobe epilepsy, often develops after an initial precipitating injury affecting the immature brain. To analyse early processes in epileptogenesis we used the juvenile pilocarpine model to study status epilepticus (SE)-induced changes in expression of key components in the glutamate-glutamine cycle, known to be affected in MTS patients. SE was induced by Li(+) /pilocarpine injection in 21-day-old rats. At 2-19 weeks after SE hippocampal protein expression was analysed by immunohistochemistry and neuron damage by FluoroJade staining. Spontaneous seizures occurred in at least 44% of animals 15-18 weeks after SE. As expected in this model, we did not observe loss of principal hippocampal neurons. Neuron damage was most pronounced in the hilus, where we also detected progressive loss of parvalbumin-positive GABAergic interneurons. Hilar neuron loss (or end-folium sclerosis), a common feature in patients with MTS, was accompanied by a progressively decreased glutamine synthetase (GS)-immunoreactivity from 2 (-15%) to 19 weeks (-33.5%) after SE. Immunoreactivity for excitatory amino-acid transporters, vesicular glutamate transporter 1 and glial fibrillary acidic protein was unaffected. Our data show that SE elicited in 21-day-old rats induces a progressive reduction in hilar GS expression without affecting other key components of the glutamate-glutamine cycle. Reduced expression of glial enzyme GS was first detected 2 weeks after SE, and thus clearly before spontaneous recurrent seizures occurred. These results support the hypothesis that reduced GS expression is an early event in the development of hippocampal sclerosis in MTS patients and emphasize the importance of astrocytes in early epileptogenesis.
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Affiliation(s)
- W Saskia van der Hel
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Universiteitsweg 100, 3584CG, Utrecht, The Netherlands; Division of Surgical Specialties, Department of Anatomy, University Medical Center Utrecht, Utrecht, The Netherlands
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van Campen JS, Jansen FE, de Graan PNE, Braun KPJ, Joels M. Early life stress in epilepsy: a seizure precipitant and risk factor for epileptogenesis. Epilepsy Behav 2014; 38:160-71. [PMID: 24144618 DOI: 10.1016/j.yebeh.2013.09.029] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Revised: 09/17/2013] [Accepted: 09/19/2013] [Indexed: 10/26/2022]
Abstract
Stress can influence epilepsy in multiple ways. A relation between stress and seizures is often experienced by patients with epilepsy. Numerous questionnaire and diary studies have shown that stress is the most often reported seizure-precipitating factor in epilepsy. Acute stress can provoke epileptic seizures, and chronic stress increases seizure frequency. In addition to its effects on seizure susceptibility in patients with epilepsy, stress might also increase the risk of epilepsy development, especially when the stressors are severe, prolonged, or experienced early in life. Although the latter has not been fully resolved in humans, various preclinical epilepsy models have shown increased seizure susceptibility in naïve rodents after prenatal and early postnatal stress exposure. In the current review, we first provide an overview of the effects of stress on the brain. Thereafter, we discuss human as well as preclinical studies evaluating the relation between stress, epileptic seizures, and epileptogenesis, focusing on the epileptogenic effects of early life stress. Increased knowledge on the interaction between early life stress, seizures, and epileptogenesis could improve patient care and provide a basis for new treatment strategies for epilepsy.
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Affiliation(s)
- Jolien S van Campen
- Department of Pediatric Neurology, Brain Center Rudolf Magnus, University Medical Center Utrecht, The Netherlands; Department of Neuroscience & Pharmacology, Brain Center Rudolf Magnus, University Medical Center Utrecht, The Netherlands.
| | - Floor E Jansen
- Department of Pediatric Neurology, Brain Center Rudolf Magnus, University Medical Center Utrecht, The Netherlands
| | - Pierre N E de Graan
- Department of Neuroscience & Pharmacology, Brain Center Rudolf Magnus, University Medical Center Utrecht, The Netherlands
| | - Kees P J Braun
- Department of Pediatric Neurology, Brain Center Rudolf Magnus, University Medical Center Utrecht, The Netherlands
| | - Marian Joels
- Department of Neuroscience & Pharmacology, Brain Center Rudolf Magnus, University Medical Center Utrecht, The Netherlands
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Hessel EVS, de Wit M, Wolterink-Donselaar IG, Karst H, de Graaff E, van Lith HA, de Bruijn E, de Sonnaville S, Verbeek NE, Lindhout D, de Kovel CGF, Koeleman BPC, van Kempen M, Brilstra E, Cuppen E, Loos M, Spijker SS, Kan AA, Baars SE, van Rijen PC, Gosselaar PH, Groot Koerkamp MJA, Holstege FCP, van Duijn C, Vergeer J, Moll HA, Taubøll E, Heuser K, Ramakers GMJ, Pasterkamp RJ, van Nieuwenhuizen O, Hoogenraad CC, Kas MJH, de Graan PNE. Identification of Srp9 as a febrile seizure susceptibility gene. Ann Clin Transl Neurol 2014; 1:239-50. [PMID: 25590037 PMCID: PMC4292741 DOI: 10.1002/acn3.48] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Accepted: 02/07/2014] [Indexed: 12/16/2022] Open
Abstract
OBJECTIVE Febrile seizures (FS) are the most common seizure type in young children. Complex FS are a risk factor for mesial temporal lobe epilepsy (mTLE). To identify new FS susceptibility genes we used a forward genetic strategy in mice and subsequently analyzed candidate genes in humans. METHODS We mapped a quantitative trait locus (QTL1) for hyperthermia-induced FS on mouse chromosome 1, containing the signal recognition particle 9 (Srp9) gene. Effects of differential Srp9 expression were assessed in vivo and in vitro. Hippocampal SRP9 expression and genetic association were analyzed in FS and mTLE patients. RESULTS Srp9 was differentially expressed between parental strains C57BL/6J and A/J. Chromosome substitution strain 1 (CSS1) mice exhibited lower FS susceptibility and Srp9 expression than C57BL/6J mice. In vivo knockdown of brain Srp9 reduced FS susceptibility. Mice with reduced Srp9 expression and FS susceptibility, exhibited reduced hippocampal AMPA and NMDA currents. Downregulation of neuronal Srp9 reduced surface expression of AMPA receptor subunit GluA1. mTLE patients with antecedent FS had higher SRP9 expression than patients without. SRP9 promoter SNP rs12403575(G/A) was genetically associated with FS and mTLE. INTERPRETATION Our findings identify SRP9 as a novel FS susceptibility gene and indicate that SRP9 conveys its effects through endoplasmic reticulum (ER)-dependent synthesis and trafficking of membrane proteins, such as glutamate receptors. Discovery of this new FS gene and mechanism may provide new leads for early diagnosis and treatment of children with complex FS at risk for mTLE.
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Affiliation(s)
- Ellen V S Hessel
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center UtrechtUtrecht, The Netherlands
| | - Marina de Wit
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center UtrechtUtrecht, The Netherlands
| | - Inge G Wolterink-Donselaar
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center UtrechtUtrecht, The Netherlands
| | - Henk Karst
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center UtrechtUtrecht, The Netherlands
| | - Esther de Graaff
- Cell Biology, Faculty of Science, Utrecht UniversityUtrecht, The Netherlands
| | - Hein A van Lith
- Program Emotion and Cognition, Division of Animal Welfare and Laboratory Animal Science, Department of Animals in Science and Society, Faculty of Veterinary Medicine, Utrecht University and Brain Center Rudolf Magnus, University Medical Center UtrechtUtrecht, The Netherlands
| | - Ewart de Bruijn
- Hubrecht Institute-KNAW and University Medical Center UtrechtUtrecht, The Netherlands
| | - Sophietje de Sonnaville
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center UtrechtUtrecht, The Netherlands
| | - Nienke E Verbeek
- Department of Medical Genetics, University Medical Center UtrechtUtrecht, The Netherlands
| | - Dick Lindhout
- Department of Medical Genetics, University Medical Center UtrechtUtrecht, The Netherlands
- SEIN Epilepsy Institute in the NetherlandsHeemstede, The Netherlands
| | - Carolien G F de Kovel
- Department of Medical Genetics, University Medical Center UtrechtUtrecht, The Netherlands
| | - Bobby P C Koeleman
- Department of Medical Genetics, University Medical Center UtrechtUtrecht, The Netherlands
| | - Marjan van Kempen
- Department of Medical Genetics, University Medical Center UtrechtUtrecht, The Netherlands
| | - Eva Brilstra
- Department of Medical Genetics, University Medical Center UtrechtUtrecht, The Netherlands
| | - Edwin Cuppen
- Hubrecht Institute-KNAW and University Medical Center UtrechtUtrecht, The Netherlands
- Department of Medical Genetics, University Medical Center UtrechtUtrecht, The Netherlands
| | - Maarten Loos
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU UniversityAmsterdam, The Netherlands
| | - Sabine S Spijker
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU UniversityAmsterdam, The Netherlands
| | - Anne A Kan
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center UtrechtUtrecht, The Netherlands
| | - Susanne E Baars
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center UtrechtUtrecht, The Netherlands
- Master program Neuroscience and Cognition, Utrecht UniversityUtrecht, The Netherlands
| | - Peter C van Rijen
- Department of Neurosurgery, Brain Center Rudolf Magnus, University Medical Center UtrechtUtrecht, The Netherlands
| | - Peter H Gosselaar
- Department of Neurosurgery, Brain Center Rudolf Magnus, University Medical Center UtrechtUtrecht, The Netherlands
| | | | - Frank C P Holstege
- Department of Molecular Cancer Research, University Medical Center UtrechtUtrecht, The Netherlands
| | - Cornelia van Duijn
- Department of Epidemiology, Erasmus University Medical CenterRotterdam, The Netherlands
| | - Jeanette Vergeer
- Department of Epidemiology, Erasmus University Medical CenterRotterdam, The Netherlands
| | - Henriette A Moll
- Department of Pediatrics, Erasmus Medical CenterRotterdam, The Netherlands
| | - Erik Taubøll
- Department of Neurology, Oslo University HospitalOslo, Norway
| | - Kjell Heuser
- Department of Neurology, Oslo University HospitalOslo, Norway
| | - Geert M J Ramakers
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center UtrechtUtrecht, The Netherlands
| | - R Jeroen Pasterkamp
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center UtrechtUtrecht, The Netherlands
| | - Onno van Nieuwenhuizen
- Department of Child Neurology, Brain Center Rudolf Magnus, University Medical Center UtrechtUtrecht, The Netherlands
| | - Casper C Hoogenraad
- Cell Biology, Faculty of Science, Utrecht UniversityUtrecht, The Netherlands
| | - Martien J H Kas
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center UtrechtUtrecht, The Netherlands
| | - Pierre N E de Graan
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center UtrechtUtrecht, The Netherlands
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Noorlander CW, Tijsseling D, Hessel EVS, de Vries WB, Derks JB, Visser GHA, de Graan PNE. Antenatal glucocorticoid treatment affects hippocampal development in mice. PLoS One 2014; 9:e85671. [PMID: 24465645 PMCID: PMC3899077 DOI: 10.1371/journal.pone.0085671] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Accepted: 11/29/2013] [Indexed: 11/18/2022] Open
Abstract
Synthetic glucocorticoids are administered to pregnant women at risk for preterm delivery, to enhance fetal lung maturation. The benefit of this treatment is well established, however caution is necessary because of possible unwanted side effects on development of different organ systems, including the brain. Actions of glucocorticoids are mediated by corticosteroid receptors, which are highly expressed in the hippocampus, a brain structure involved in cognitive functions. Therefore, we analyzed the effects of a single antenatal dexamethasone treatment on the development of the mouse hippocampus. A clinically relevant dose of dexamethasone (0.4 mg/kg) was administered to pregnant mice at embryonic day 15.5 and the hippocampus was analyzed from embryonic day 16 until adulthood. We investigated the effects of dexamethasone treatment on anatomical changes, apoptosis and proliferation in the hippocampus, hippocampal volume and on total body weight. Our results show that dexamethasone treatment reduced body weight and hippocampal volume transiently during development, but these effects were no longer detected at adulthood. Dexamethasone treatment increased the number of apoptotic cells in the hippocampus until birth, but postnatally no effects of dexamethasone treatment on apoptosis were found. During the phase with increased apoptosis, dexamethasone treatment reduced the number of proliferating cells in the subgranular zone of the dentate gyrus. The number of proliferative cells was increased at postnatal day 5 and 10, but was decreased again at the adult stage. This latter long-term and negative effect of antenatal dexamethasone treatment on the number of proliferative cells in the hippocampus may have important implications for hippocampal network function.
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Affiliation(s)
- Cornelle W. Noorlander
- Brain Center Rudolf Magnus, Department of Neuroscience and Pharmacology, University Medical Center Utrecht, Utrecht, The Netherlands
- Department of Obstetrics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Deodata Tijsseling
- Department of Obstetrics, University Medical Center Utrecht, Utrecht, The Netherlands
- * E-mail:
| | - Ellen V. S. Hessel
- Brain Center Rudolf Magnus, Department of Neuroscience and Pharmacology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Willem B. de Vries
- Department of Neonatology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Jan B. Derks
- Department of Obstetrics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Gerard H. A. Visser
- Department of Obstetrics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Pierre N. E. de Graan
- Brain Center Rudolf Magnus, Department of Neuroscience and Pharmacology, University Medical Center Utrecht, Utrecht, The Netherlands
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Kasperavičiūtė D, Catarino CB, Matarin M, Leu C, Novy J, Tostevin A, Leal B, Hessel EVS, Hallmann K, Hildebrand MS, Dahl HHM, Ryten M, Trabzuni D, Ramasamy A, Alhusaini S, Doherty CP, Dorn T, Hansen J, Krämer G, Steinhoff BJ, Zumsteg D, Duncan S, Kälviäinen RK, Eriksson KJ, Kantanen AM, Pandolfo M, Gruber-Sedlmayr U, Schlachter K, Reinthaler EM, Stogmann E, Zimprich F, Théâtre E, Smith C, O’Brien TJ, Meng Tan K, Petrovski S, Robbiano A, Paravidino R, Zara F, Striano P, Sperling MR, Buono RJ, Hakonarson H, Chaves J, Costa PP, Silva BM, da Silva AM, de Graan PNE, Koeleman BPC, Becker A, Schoch S, von Lehe M, Reif PS, Rosenow F, Becker F, Weber Y, Lerche H, Rössler K, Buchfelder M, Hamer HM, Kobow K, Coras R, Blumcke I, Scheffer IE, Berkovic SF, Weale ME, Delanty N, Depondt C, Cavalleri GL, Kunz WS, Sisodiya SM. Epilepsy, hippocampal sclerosis and febrile seizures linked by common genetic variation around SCN1A. Brain 2013; 136:3140-50. [PMID: 24014518 PMCID: PMC3784283 DOI: 10.1093/brain/awt233] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Revised: 06/28/2013] [Accepted: 07/02/2013] [Indexed: 01/01/2023] Open
Abstract
Epilepsy comprises several syndromes, amongst the most common being mesial temporal lobe epilepsy with hippocampal sclerosis. Seizures in mesial temporal lobe epilepsy with hippocampal sclerosis are typically drug-resistant, and mesial temporal lobe epilepsy with hippocampal sclerosis is frequently associated with important co-morbidities, mandating the search for better understanding and treatment. The cause of mesial temporal lobe epilepsy with hippocampal sclerosis is unknown, but there is an association with childhood febrile seizures. Several rarer epilepsies featuring febrile seizures are caused by mutations in SCN1A, which encodes a brain-expressed sodium channel subunit targeted by many anti-epileptic drugs. We undertook a genome-wide association study in 1018 people with mesial temporal lobe epilepsy with hippocampal sclerosis and 7552 control subjects, with validation in an independent sample set comprising 959 people with mesial temporal lobe epilepsy with hippocampal sclerosis and 3591 control subjects. To dissect out variants related to a history of febrile seizures, we tested cases with mesial temporal lobe epilepsy with hippocampal sclerosis with (overall n = 757) and without (overall n = 803) a history of febrile seizures. Meta-analysis revealed a genome-wide significant association for mesial temporal lobe epilepsy with hippocampal sclerosis with febrile seizures at the sodium channel gene cluster on chromosome 2q24.3 [rs7587026, within an intron of the SCN1A gene, P = 3.36 × 10(-9), odds ratio (A) = 1.42, 95% confidence interval: 1.26-1.59]. In a cohort of 172 individuals with febrile seizures, who did not develop epilepsy during prospective follow-up to age 13 years, and 6456 controls, no association was found for rs7587026 and febrile seizures. These findings suggest SCN1A involvement in a common epilepsy syndrome, give new direction to biological understanding of mesial temporal lobe epilepsy with hippocampal sclerosis with febrile seizures, and open avenues for investigation of prognostic factors and possible prevention of epilepsy in some children with febrile seizures.
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Affiliation(s)
- Dalia Kasperavičiūtė
- 1 NIHR University College London Hospitals Biomedical Research Centre, Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Claudia B. Catarino
- 1 NIHR University College London Hospitals Biomedical Research Centre, Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
- 2 Epilepsy Society, Chalfont-St-Peter, SL9 0RJ, UK
| | - Mar Matarin
- 1 NIHR University College London Hospitals Biomedical Research Centre, Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Costin Leu
- 1 NIHR University College London Hospitals Biomedical Research Centre, Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Jan Novy
- 1 NIHR University College London Hospitals Biomedical Research Centre, Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
- 2 Epilepsy Society, Chalfont-St-Peter, SL9 0RJ, UK
| | - Anna Tostevin
- 1 NIHR University College London Hospitals Biomedical Research Centre, Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
- 2 Epilepsy Society, Chalfont-St-Peter, SL9 0RJ, UK
| | - Bárbara Leal
- 3 Immunogenetics Laboratory, University of Porto, 4050-313 Porto, Portugal
- 4 UMIB - Instituto Ciências Biomédicas Abel Salazar, University of Porto, 4099-003 Porto, Portugal
| | - Ellen V. S. Hessel
- 5 Rudolf Magnus Institute of Neuroscience, Department of Neuroscience and Pharmacology, University Medical Centre Utrecht, 3584 CG Utrecht, The Netherlands
| | - Kerstin Hallmann
- 6 Department of Epileptology, University of Bonn, 53105 Bonn, Germany
- 7 Life & Brain Centre, University of Bonn, 53105 Bonn, Germany
| | - Michael S. Hildebrand
- 8 Epilepsy Research Centre, Austin Health, University of Melbourne, Melbourne VIC 3084, Australia
| | - Hans-Henrik M. Dahl
- 8 Epilepsy Research Centre, Austin Health, University of Melbourne, Melbourne VIC 3084, Australia
| | - Mina Ryten
- 9 Department of Molecular Neuroscience, UCL Institute of Neurology, London, WC1N 3BG, UK
- 10 Reta Lila Weston Institute, UCL Institute of Neurology, London, WC1N 3BG, UK
| | - Daniah Trabzuni
- 9 Department of Molecular Neuroscience, UCL Institute of Neurology, London, WC1N 3BG, UK
- 10 Reta Lila Weston Institute, UCL Institute of Neurology, London, WC1N 3BG, UK
- 11 Department of Genetics, King Faisal Specialist Hospital and Research Centre, Riyadh, 11211, Saudi Arabia
| | - Adaikalavan Ramasamy
- 9 Department of Molecular Neuroscience, UCL Institute of Neurology, London, WC1N 3BG, UK
- 10 Reta Lila Weston Institute, UCL Institute of Neurology, London, WC1N 3BG, UK
- 12 Department of Medical and Molecular Genetics, King’s College London, Guy's Hospital, London, SE1 9RT, UK
| | - Saud Alhusaini
- 13 Molecular and Cellular Therapeutics Department, Royal College of Surgeons in Ireland, Dublin 2, Ireland
- 14 Brain Morphometry Laboratory, Neurophysics Department, Beaumont Hospital, Dublin 9, Ireland
| | - Colin P. Doherty
- 15 Department of Neurology, St James’ Hospital, Dublin 8, Ireland
| | - Thomas Dorn
- 16 Swiss Epilepsy Centre, 8008 Zurich, Switzerland
| | - Jörg Hansen
- 16 Swiss Epilepsy Centre, 8008 Zurich, Switzerland
| | | | | | - Dominik Zumsteg
- 18 Department of Neurology, University Hospital Zurich, 8091 Zurich, Switzerland
| | - Susan Duncan
- 19 Edinburgh and South East Scotland Epilepsy Service, Western General Hospital Edinburgh, EH4 2XU, Scotland, UK
| | - Reetta K. Kälviäinen
- 20 Kuopio Epilepsy Centre, Kuopio University Hospital, 70211 Kuopio, Finland
- 21 Department of Neurology, Institute of Clinical Medicine, University of Eastern Finland, 70211 Kuopio, Finland
| | - Kai J. Eriksson
- 22 Paediatric Neurology Unit, Tampere University Hospital and Paediatric Research Centre, University of Tampere, 33521 Tampere, Finland
| | - Anne-Mari Kantanen
- 20 Kuopio Epilepsy Centre, Kuopio University Hospital, 70211 Kuopio, Finland
| | - Massimo Pandolfo
- 23 Department of Neurology, Hôpital Erasme, Université Libre de Bruxelles, 1070 Brussels, Belgium
| | | | - Kurt Schlachter
- 25 Department of Paediatrics, LKH Bregenz, 6900 Bregenz, Austria
| | - Eva M. Reinthaler
- 26 Department of Clinical Neurology, Medical University of Vienna, 1090 Vienna, Austria
| | - Elisabeth Stogmann
- 26 Department of Clinical Neurology, Medical University of Vienna, 1090 Vienna, Austria
| | - Fritz Zimprich
- 26 Department of Clinical Neurology, Medical University of Vienna, 1090 Vienna, Austria
| | - Emilie Théâtre
- 27 Groupe Interdisciplinaire de Génoprotéomique Appliquée (GIGA-R) and Faculty of Veterinary Medicine, University of Liège, 4000 Liège, Belgium
- 28 Unit of Gastroenterology, Centre Hospitalier Universitaire, University of Liège, 4000 Liège, Belgium
| | - Colin Smith
- 29 Department of Neuropathology, MRC Sudden Death Brain Bank Project, University of Edinburgh, Wilkie Building, Edinburgh, EH8 9AG, UK
| | - Terence J. O’Brien
- 30 Departments of Medicine and Neurology, Royal Melbourne Hospital, University of Melbourne, Melbourne VIC 3050, Australia
- 31 Melbourne Brain Centre, University of Melbourne, Melbourne VIC 3084, Australia
| | - K. Meng Tan
- 30 Departments of Medicine and Neurology, Royal Melbourne Hospital, University of Melbourne, Melbourne VIC 3050, Australia
- 31 Melbourne Brain Centre, University of Melbourne, Melbourne VIC 3084, Australia
| | - Slave Petrovski
- 30 Departments of Medicine and Neurology, Royal Melbourne Hospital, University of Melbourne, Melbourne VIC 3050, Australia
- 31 Melbourne Brain Centre, University of Melbourne, Melbourne VIC 3084, Australia
- 32 Department of Medicine, Austin Health, University of Melbourne, Melbourne VIC 3084, Australia
| | - Angela Robbiano
- 33 Department of Neurosciences, Laboratory of Neurogenetics, University of Genoa, ‘G. Gaslini’ Institute, 16147 Genova, Italy
| | - Roberta Paravidino
- 33 Department of Neurosciences, Laboratory of Neurogenetics, University of Genoa, ‘G. Gaslini’ Institute, 16147 Genova, Italy
| | - Federico Zara
- 33 Department of Neurosciences, Laboratory of Neurogenetics, University of Genoa, ‘G. Gaslini’ Institute, 16147 Genova, Italy
| | - Pasquale Striano
- 34 Paediatric Neurology and Muscular Diseases Unit, Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, ‘G. Gaslini’ Institute, 16147 Genova, Italy
| | - Michael R. Sperling
- 35 Department of Neurology, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Russell J. Buono
- 36 Department of Biomedical Science, Cooper Medical School of Rowan University, Camden, NJ 08103, USA
| | - Hakon Hakonarson
- 37 Centre for Applied Genomics, The Children’s Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-4318, USA
| | - João Chaves
- 38 Department of Neurological Disorders and Senses, Hospital Santo António / Centro Hospitalar do Porto, 4099-001 Porto, Portugal
| | - Paulo P. Costa
- 3 Immunogenetics Laboratory, University of Porto, 4050-313 Porto, Portugal
- 4 UMIB - Instituto Ciências Biomédicas Abel Salazar, University of Porto, 4099-003 Porto, Portugal
- 39 Instituto Nacional de Saúde Dr. Ricardo Jorge (INSA), 4049-019 Porto, Portugal
| | - Berta M. Silva
- 3 Immunogenetics Laboratory, University of Porto, 4050-313 Porto, Portugal
- 4 UMIB - Instituto Ciências Biomédicas Abel Salazar, University of Porto, 4099-003 Porto, Portugal
| | - António M. da Silva
- 4 UMIB - Instituto Ciências Biomédicas Abel Salazar, University of Porto, 4099-003 Porto, Portugal
- 38 Department of Neurological Disorders and Senses, Hospital Santo António / Centro Hospitalar do Porto, 4099-001 Porto, Portugal
| | - Pierre N. E. de Graan
- 5 Rudolf Magnus Institute of Neuroscience, Department of Neuroscience and Pharmacology, University Medical Centre Utrecht, 3584 CG Utrecht, The Netherlands
| | - Bobby P. C. Koeleman
- 40 Department of Medical Genetics, University Medical Centre Utrecht, 3584 CG Utrecht, The Netherlands
| | - Albert Becker
- 41 Department of Neuropathology, University of Bonn, 53105 Bonn, Germany
| | - Susanne Schoch
- 41 Department of Neuropathology, University of Bonn, 53105 Bonn, Germany
| | - Marec von Lehe
- 42 Department of Neurosurgery, University of Bochum, 44892 Bochum, Germany
| | - Philipp S. Reif
- 43 Epilepsy-Centre Hessen, Department of Neurology, University Hospitals and Philipps-University Marburg, 35043 Marburg, Germany
| | - Felix Rosenow
- 43 Epilepsy-Centre Hessen, Department of Neurology, University Hospitals and Philipps-University Marburg, 35043 Marburg, Germany
| | - Felicitas Becker
- 44 Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, 72076 Tübingen, Germany
| | - Yvonne Weber
- 44 Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, 72076 Tübingen, Germany
| | - Holger Lerche
- 44 Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, 72076 Tübingen, Germany
| | - Karl Rössler
- 45 Department of Neurosurgery, University Hospital Erlangen, 91054 Erlangen, Germany
| | - Michael Buchfelder
- 45 Department of Neurosurgery, University Hospital Erlangen, 91054 Erlangen, Germany
| | - Hajo M. Hamer
- 46 Department of Neurology, Epilepsy Centre, University Hospital Erlangen, 91054 Erlangen, Germany
| | - Katja Kobow
- 47 Department of Neuropathology, University Hospital Erlangen, 91054 Erlangen, Germany
| | - Roland Coras
- 47 Department of Neuropathology, University Hospital Erlangen, 91054 Erlangen, Germany
| | - Ingmar Blumcke
- 47 Department of Neuropathology, University Hospital Erlangen, 91054 Erlangen, Germany
| | - Ingrid E. Scheffer
- 8 Epilepsy Research Centre, Austin Health, University of Melbourne, Melbourne VIC 3084, Australia
- 48 Florey Institute of Neuroscience and Mental Health, Melbourne VIC 3010, Australia
- 49 Department of Paediatrics, University of Melbourne, Royal Children’s Hospital, Melbourne VIC 3052, Australia
| | - Samuel F. Berkovic
- 8 Epilepsy Research Centre, Austin Health, University of Melbourne, Melbourne VIC 3084, Australia
| | - Michael E. Weale
- 12 Department of Medical and Molecular Genetics, King’s College London, Guy's Hospital, London, SE1 9RT, UK
| | - UK Brain Expression Consortium
- 9 Department of Molecular Neuroscience, UCL Institute of Neurology, London, WC1N 3BG, UK
- 10 Reta Lila Weston Institute, UCL Institute of Neurology, London, WC1N 3BG, UK
| | - Norman Delanty
- 13 Molecular and Cellular Therapeutics Department, Royal College of Surgeons in Ireland, Dublin 2, Ireland
- 50 Department of Neurology, Beaumont Hospital, Dublin 9, Ireland
| | - Chantal Depondt
- 23 Department of Neurology, Hôpital Erasme, Université Libre de Bruxelles, 1070 Brussels, Belgium
| | - Gianpiero L. Cavalleri
- 13 Molecular and Cellular Therapeutics Department, Royal College of Surgeons in Ireland, Dublin 2, Ireland
| | - Wolfram S. Kunz
- 6 Department of Epileptology, University of Bonn, 53105 Bonn, Germany
- 7 Life & Brain Centre, University of Bonn, 53105 Bonn, Germany
| | - Sanjay M. Sisodiya
- 1 NIHR University College London Hospitals Biomedical Research Centre, Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
- 2 Epilepsy Society, Chalfont-St-Peter, SL9 0RJ, UK
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9
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van der Hel WS, van Eijsden P, Bos IWM, de Graaf RA, Behar KL, van Nieuwenhuizen O, de Graan PNE, Braun KPJ. In vivo MRS and histochemistry of status epilepticus-induced hippocampal pathology in a juvenile model of temporal lobe epilepsy. NMR Biomed 2013; 26:132-140. [PMID: 22806932 DOI: 10.1002/nbm.2828] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Revised: 05/16/2012] [Accepted: 05/21/2012] [Indexed: 06/01/2023]
Abstract
Childhood status epilepticus (SE) initiates an epileptogenic process that leads to spontaneous seizures and hippocampal pathology characterized by neuronal loss, gliosis and an imbalance between excitatory and inhibitory neurotransmission. It remains unclear whether these changes are a cause or consequence of chronic epilepsy. In this study, in vivo MRS was used in a post-SE juvenile rat model of temporal lobe epilepsy (TLE) to establish the temporal evolution of hippocampal injury and neurotransmitter imbalance. SE was induced in P21 rats by injection of lithium and pilocarpine. Four and eight weeks after SE, in vivo (1) H and γ-aminobutyric acid (GABA)-edited MRS of the hippocampus was performed in combination with dedicated ex vivo immunohistochemistry for the interpretation and validation of MRS findings. MRS showed a 12% decrease (p<0.0001) in N-acetylaspartate and a 15% increase (p=0.0226) in choline-containing compound concentrations, indicating neuronal death and gliosis, respectively. These results were confirmed by FluoroJade and vimentin staining. Furthermore, severe and progressive decreases in GABA (-41%, p<0.001) and glutamate (Glu) (-17%, p<0.001) were found. The specific severity of GABAergic cell death was confirmed by parvalbumin immunoreactivity (-68%, p<0.001). Unexpectedly, we found changes in glutamine (Gln), the metabolic precursor of both GABA and Glu. Gln increased at 4 weeks (+36%, p<0.001), but returned to control levels at 8 weeks. This decrease was consistent with the simultaneous decrease in glutamine synthase immunoreactivity (-32%, p=0.037). In vivo MRS showed gliosis and (predominantly GABAergic) neuronal loss. In addition, an increase in Gln was detected, accompanied by a decrease in glutamine synthase immunoreactivity. This may reflect glutamine synthase downregulation in order to normalize Gln levels. These changes occurred before spontaneous recurrent seizures were present but, by creating a pre-epileptic state, may play a role in epileptogenesis. MRS can be applied in a clinical setting and may be used as a noninvasive tool to monitor the development of TLE.
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Affiliation(s)
- W Saskia van der Hel
- Rudolf Magnus Institute of Neuroscience, Department of Neuroscience and Pharmacology, University Medical Center Utrecht, the Netherlands
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10
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Kan AA, de Jager W, de Wit M, Heijnen C, van Zuiden M, Ferrier C, van Rijen P, Gosselaar P, Hessel E, van Nieuwenhuizen O, de Graan PNE. Protein expression profiling of inflammatory mediators in human temporal lobe epilepsy reveals co-activation of multiple chemokines and cytokines. J Neuroinflammation 2012; 9:207. [PMID: 22935090 PMCID: PMC3489559 DOI: 10.1186/1742-2094-9-207] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Accepted: 07/30/2012] [Indexed: 11/25/2022] Open
Abstract
Mesial temporal lobe epilepsy (mTLE) is a chronic and often treatment-refractory brain disorder characterized by recurrent seizures originating from the hippocampus. The pathogenic mechanisms underlying mTLE remain largely unknown. Recent clinical and experimental evidence supports a role of various inflammatory mediators in mTLE. Here, we performed protein expression profiling of 40 inflammatory mediators in surgical resection material from mTLE patients with and without hippocampal sclerosis, and autopsy controls using a multiplex bead-based immunoassay. In mTLE patients we identified 21 upregulated inflammatory mediators, including 10 cytokines and 7 chemokines. Many of these upregulated mediators have not previously been implicated in mTLE (for example, CCL22, IL-7 and IL-25). Comparing the three patient groups, two main hippocampal expression patterns could be distinguished, pattern I (for example, IL-10 and IL-25) showing increased expression in mTLE + HS patients compared to mTLE-HS and controls, and pattern II (for example, CCL4 and IL-7) showing increased expression in both mTLE groups compared to controls. Upregulation of a subset of inflammatory mediators (for example, IL-25 and IL-7) could not only be detected in the hippocampus of mTLE patients, but also in the neocortex. Principle component analysis was used to cluster the inflammatory mediators into several components. Follow-up analyses of the identified components revealed that the three patient groups could be discriminated based on their unique expression profiles. Immunocytochemistry showed that IL-25 IR (pattern I) and CCL4 IR (pattern II) were localized in astrocytes and microglia, whereas IL-25 IR was also detected in neurons. Our data shows co-activation of multiple inflammatory mediators in hippocampus and neocortex of mTLE patients, indicating activation of multiple pro- and anti-epileptogenic immune pathways in this disease.
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Affiliation(s)
- Anne A Kan
- Department of Neuroscience and Pharmacology, Rudolf Magnus Institute of Neuroscience, Universiteitsweg 100, 3584 CG, Utrecht, The Netherlands
| | - Wilco de Jager
- Department of Pediatric Immunology, University Medical Center Utrecht, Heidelberglaan 100, Utrecht, The Netherlands
| | - Marina de Wit
- Department of Neuroscience and Pharmacology, Rudolf Magnus Institute of Neuroscience, Universiteitsweg 100, 3584 CG, Utrecht, The Netherlands
| | - Cobi Heijnen
- Laboratory of Neuroimmunology and Developmental Origins of Disease, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands
| | - Mirjam van Zuiden
- Laboratory of Neuroimmunology and Developmental Origins of Disease, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands
| | - Cyrill Ferrier
- Department of Neurology and Neurosurgery, University Medical Center Utrecht, Heidelberglaan 100, Utrecht, The Netherlands
| | - Peter van Rijen
- Department of Neurology and Neurosurgery, University Medical Center Utrecht, Heidelberglaan 100, Utrecht, The Netherlands
| | - Peter Gosselaar
- Department of Neurology and Neurosurgery, University Medical Center Utrecht, Heidelberglaan 100, Utrecht, The Netherlands
| | - Ellen Hessel
- Department of Neuroscience and Pharmacology, Rudolf Magnus Institute of Neuroscience, Universiteitsweg 100, 3584 CG, Utrecht, The Netherlands
| | - Onno van Nieuwenhuizen
- Department of Child Neurology, University Medical Center Utrecht, Heidelberglaan 100, Utrecht, The Netherlands
| | - Pierre N E de Graan
- Department of Neuroscience and Pharmacology, Rudolf Magnus Institute of Neuroscience, Universiteitsweg 100, 3584 CG, Utrecht, The Netherlands
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11
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Hessel EVS, van Lith HA, Wolterink-Donselaar IG, de Wit M, Hendrickx DAE, Kas MJH, de Graan PNE. Mapping an X-linked locus that influences heat-induced febrile seizures in mice. Epilepsia 2012; 53:1399-410. [PMID: 22780306 DOI: 10.1111/j.1528-1167.2012.03575.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
PURPOSE Febrile seizures (FS) are the most common seizure type in children between the age of 6 months and 5 years. Although FS are largely benign, recurrent FS are a major risk factor for developing temporal lobe epilepsy (TLE) later in life. The mechanisms underlying FS are largely unknown; however, family and twin studies indicate that FS susceptibility is under complex genetic control. We have recently developed a phenotypic screen to study the genetics of FS susceptibility in mice. Using this screen in a phenotype-driven genetic strategy we analyzed the C57BL/6J-Chr #(A)/NaJ chromosome substitution strain (CSS) panel. In each CSS line one chromosome of the A/J strain is substituted in a genetically homogeneous C57BL/6J background. The analysis of the CSS panel revealed that A/J chromosomes 1, 2, 6, 10, 13, and X carry at least one quantitative trait locus (QTL) for heat-induced FS susceptibility. The fact that many X-linked genes are highly expressed in the brain and have been implicated in human developmental disorders often presenting with seizures (like fragile X mental retardation) prompted us to map the chromosome X QTL. METHODS C57BL/6J mice were mated with C57BL/6J-Chr X(A) /NaJ (CSSX) to generate F(2)-generations-CXBL6 and BL6CX-originating from CSSX or C57BL/6J mothers, respectively. Heat-induced FS were elicited on postnatal day 14 by exposure to a controlled warm airstream of 50°C. The latency to heat-induced FS is our phenotype. This phenotype has previously been validated by video-electroencephalography (EEG) monitoring. After phenotyping and genotyping the F(2)-population, QTL analysis was performed using R/QTL software. KEY FINDINGS QTL analysis revealed a significant peak with an LOD-score of 3.25. The 1-LOD confidence interval (149,886,866-158,836,462 bp) comprises 52 protein coding genes, of which 34 are known to be brain expressed. Two of these brain-expressed genes have previously been linked to X-linked epilepsies, namely Cdkl5 and Pdha1. SIGNIFICANCE Our results show that the mouse genetics of X-linked FS susceptibility is complex, and that our heat-induced FS-driven genetic approach is a powerful tool for use in unraveling the complexities of this trait in mice. Fine-mapping and functional studies will be required to further identify the X-linked FS susceptibility genes.
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Affiliation(s)
- Ellen V S Hessel
- Rudolf Magnus Institute of Neuroscience, Department of Neuroscience and Pharmacology, University Medical Center Utrecht, Utrecht, The Netherlands
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12
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Kan AA, van Erp S, Derijck AAHA, de Wit M, Hessel EVS, O'Duibhir E, de Jager W, Van Rijen PC, Gosselaar PH, de Graan PNE, Pasterkamp RJ. Genome-wide microRNA profiling of human temporal lobe epilepsy identifies modulators of the immune response. Cell Mol Life Sci 2012; 69:3127-45. [PMID: 22535415 PMCID: PMC3428527 DOI: 10.1007/s00018-012-0992-7] [Citation(s) in RCA: 147] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Revised: 03/22/2012] [Accepted: 04/02/2012] [Indexed: 10/28/2022]
Abstract
Mesial temporal lobe epilepsy (mTLE) is a chronic neurological disorder characterized by recurrent seizures. The pathogenic mechanisms underlying mTLE may involve defects in the post-transcriptional regulation of gene expression. MicroRNAs (miRNAs) are non-coding RNAs that control the expression of genes at the post-transcriptional level. Here, we performed a genome-wide miRNA profiling study to examine whether miRNA-mediated mechanisms are affected in human mTLE. miRNA profiles of the hippocampus of autopsy control patients and two mTLE patient groups were compared. This revealed segregated miRNA signatures for the three different patient groups and 165 miRNAs with up- or down-regulated expression in mTLE. miRNA in situ hybridization detected cell type-specific changes in miRNA expression and an abnormal nuclear localization of select miRNAs in neurons and glial cells of mTLE patients. Of several cellular processes implicated in mTLE, the immune response was most prominently targeted by deregulated miRNAs. Enhanced expression of inflammatory mediators was paralleled by a reduction in miRNAs that were found to target the 3'-untranslated regions of these genes in reporter assays. miR-221 and miR-222 were shown to regulate endogenous ICAM1 expression and were selectively co-expressed with ICAM1 in astrocytes in mTLE patients. Our findings suggest that miRNA changes in mTLE affect the expression of immunomodulatory proteins thereby further facilitating the immune response. This mechanism may have broad implications given the central role of astrocytes and the immune system in human neurological disease. Overall, this work extends the current concepts of human mTLE pathogenesis to the level of miRNA-mediated gene regulation.
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Affiliation(s)
- Anne A Kan
- Department of Neuroscience and Pharmacology, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG, Utrecht, The Netherlands
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13
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Notenboom RGE, Ramakers GMJ, Kamal A, Spruijt BM, de Graan PNE. Long-lasting modulation of synaptic plasticity in rat hippocampus after early-life complex febrile seizures. Eur J Neurosci 2010; 32:749-58. [PMID: 20646062 DOI: 10.1111/j.1460-9568.2010.07321.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
A small fraction of children with febrile seizures appears to develop cognitive impairments. Recent studies in a rat model of hyperthermia-induced febrile seizures indicate that prolonged febrile seizures early in life have long-lasting effects on the hippocampus and induce cognitive deficits. However, data on network plasticity and the nature of cognitive deficits are conflicting. We examined three specific measures of hippocampal plasticity in adult rats with a prior history of experimental febrile seizures: (i) activity-dependent synaptic plasticity (long-term potentiation and depression) by electrophysiological recordings of Schaffer collateral/commissural-evoked field excitatory synaptic potentials in CA1 of acute hippocampal slices; (ii) Morris water maze spatial learning and memory; and (iii) hippocampal mossy fiber plasticity by Timm histochemistry and quantification of terminal sprouting in CA3 and the dentate gyrus. We found enhanced hippocampal CA1 long-term potentiation and reduced long-term depression but normal spatial learning and memory in adult rats that were subjected to experimental febrile seizures on postnatal day 10. Furthermore, rats with experimental febrile seizures showed modest but significant sprouting of mossy fiber collaterals into the inner molecular layer of the dentate gyrus in adulthood. We conclude that enhanced CA1 long-term potentiation and mild mossy fiber sprouting occur after experimental febrile seizures, without affecting spatial learning and memory in the Morris water maze. These long-term functional and structural alterations in hippocampal plasticity are likely to play a role in the enhanced seizure susceptibility in this model of prolonged human febrile seizures but do not correlate with overt cognitive deficits.
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Affiliation(s)
- Robbert G E Notenboom
- Rudolf Magnus Institute of Neuroscience, Department of Neuroscience & Pharmacology, University Medical Center Utrecht, Utrecht, The Netherlands.
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14
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van Gassen KLI, de Wit M, van Kempen M, van der Hel WS, van Rijen PC, Jackson AP, Lindhout D, de Graan PNE. Hippocampal Nabeta3 expression in patients with temporal lobe epilepsy. Epilepsia 2009; 50:957-62. [PMID: 19385982 DOI: 10.1111/j.1528-1167.2008.02015.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Voltage-dependent sodium channels consist of a pore-forming alpha-subunit and regulatory beta-subunits. Alterations in these channels have been implicated in temporal lobe epilepsy (TLE) and several genetic epilepsy syndromes. Recently we identified Na(v)beta3 as a TLE-regulated gene. Here we performed a detailed analysis of the hippocampal expression of Na(v)beta3 in TLE patients with hippocampal sclerosis (HS) and without HS (non-HS) and compared expression with autopsy controls (ACs). Immunoblot analysis showed that Na(v)beta3 levels were dramatically reduced in the hippocampus, but not in the cortex of non-HS patients when compared to HS patients. This was confirmed by immunohistochemistry showing reduced Na(v)beta3 expression in all principal neurons of the hippocampus proper. Sequence analysis revealed no Na(v)beta3 mutations. The functional consequences of the reduced Na(v)beta3 expression in non-HS patients are unknown. Altered Na(v)beta3 expression might influence microcircuitry in the hippocampus, affecting excitability and contributing to epileptogenesis in non-HS patients. Further experiments are required to elucidate these functional possibilities.
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Affiliation(s)
- Koen L I van Gassen
- Department of Neuroscience and Pharmacology, Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht, Utrecht, The Netherlands
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15
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van Gassen KLI, de Wit M, Koerkamp MJAG, Rensen MGA, van Rijen PC, Holstege FCP, Lindhout D, de Graan PNE. Possible role of the innate immunity in temporal lobe epilepsy. Epilepsia 2007; 49:1055-65. [PMID: 18076643 DOI: 10.1111/j.1528-1167.2007.01470.x] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
PURPOSE Temporal lobe epilepsy (TLE) is a multifactorial disease often involving the hippocampus. So far the etiology of the disease has remained elusive. In some pharmacoresistant TLE patients the hippocampus is surgically resected as treatment. To investigate the involvement of the immune system in human TLE, we performed large-scale gene expression profiling on this human hippocampal tissue. METHODS Microarray analysis was performed on hippocampal specimen from TLE patients with and without hippocampal sclerosis and from autopsy controls (n = 4 per group). We used a common reference pool design to perform an unbiased three-way comparison between the two patient groups and the autopsy controls. Differentially expressed genes were statistically analyzed for significant overrepresentation of gene ontology (GO) classes. RESULTS Three-way analysis identified 618 differentially expressed genes. GO analysis identified immunity and defense genes as most affected in TLE. Particularly, the chemokines CCL3 and CCL4 were highly (>10-fold) upregulated. Other highly affected gene classes include neuropeptides, chaperonins (protein protection), and the ubiquitin/proteasome system (protein degradation). DISCUSSION The strong upregulation of CCL3 and CCL4 implicates these chemokines in the etiology and pathogenesis of TLE. These chemokines, which are mainly expressed by glia, may directly or indirectly affect neuronal excitability. Genes and gene clusters identified here may provide targets for developing new TLE therapies and candidates for genetic research.
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Affiliation(s)
- Koen L I van Gassen
- Department of Neuroscience and Pharmacology, Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht, Utrecht, The Netherlands
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16
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Abstract
There is now considerable evidence that the level of expression of the proinflammatory cytokine, interleukin-6 (IL-6), is increased in the central nervous system (CNS) during neuroinflammatory conditions such as occurs in neurological disorders and in disease and injury. However, our understanding of the consequences of increased expression of IL-6 on the CNS is still limited, especially with respect to the developing nervous system, which is known to be particularly vulnerable to environmental factors. To address this issue, we investigated the properties of cultured hippocampal neurons exposed chronically to IL-6 during the main period of morphological and physiological development, which occurs during the first 2 weeks of culture. IL-6 was tested at 500 U/mL, considered to reflect a pathophysiologic concentration. The morphological features of neuronal development in the control and IL-6-treated cultures appeared similar. However, Western blot analysis showed a significant reduction in the level of Group-II metabotropic receptors (mGluR2/3) and L-type Ca(2+) channels in the IL-6-treated cultures. A similar reduction in mGluR2/3 and L-type Ca(2+) channel protein was observed in transgenic mice that over-express IL-6 in the CNS through astrocyte production starting early in development. Analysis of Ca(2+) signals produced by spontaneous synaptic network activity in the hippocampal cultures and effects of a mGluR2/3 agonist and antagonist showed that the reduced levels of mGluR2/3 impact on the functional properties of hippocampal synaptic network activity. These results have important implications relative to the mechanisms responsible for altered CNS function during conditions associated with increased levels of IL-6 in the CNS.
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Affiliation(s)
- Elly J F Vereyken
- Department Pharmacology & Anatomy, Rudolf Magnus Institute of Neuroscience, UMCU, Utrecht, The Netherlands
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17
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Kamal A, Notenboom RGE, de Graan PNE, Ramakers GMJ. Persistent changes in action potential broadening and the slow afterhyperpolarization in rat CA1 pyramidal cells after febrile seizures. Eur J Neurosci 2006; 23:2230-4. [PMID: 16630069 DOI: 10.1111/j.1460-9568.2006.04732.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Febrile (fever-induced) seizures (FS) are the most common form of seizures during childhood and have been associated with an increased risk of epilepsy later in life. The relationship of FS to subsequent epilepsy is, however, still controversial. Insights from animal models do indicate that especially complex FS are harmful to the developing brain and contribute to a hyperexcitable state that may persist for life. Here, we determined long-lasting changes in neuronal excitability of rat hippocampal CA1 pyramidal cells after prolonged (complex) FS induced by hyperthermia on postnatal day 10. We show that hyperthermia-induced seizures at postnatal day 10 induce a long-lasting increase in the hyperpolarization-activated current I(h). Furthermore, we show that a reduction in the amount of spike broadening and in the amplitude of the slow afterhyperpolarization following FS are also likely to contribute to the hyperexcitability of the hippocampus long term.
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Affiliation(s)
- Amer Kamal
- Rudolf Magnus Institute of Neuroscience, Department of Pharmacology and Anatomy, University Medical Centre Utrecht, PO Box 85060, 3508 AB Utrecht, The Netherlands
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18
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Notenboom RGE, Hampson DR, Jansen GH, van Rijen PC, van Veelen CWM, van Nieuwenhuizen O, de Graan PNE. Up-regulation of hippocampal metabotropic glutamate receptor 5 in temporal lobe epilepsy patients. ACTA ACUST UNITED AC 2005; 129:96-107. [PMID: 16311265 DOI: 10.1093/brain/awh673] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Metabotropic glutamate receptors (mGluRs) are G protein-coupled receptors involved in the regulation of glutamatergic transmission. Recent studies indicate that excitatory group I mGluRs (mGluR1 and mGluR5) contribute to neurotoxicity and hyperexcitability during epileptogenesis. In this study, we examined the distribution of mGluR1alpha and mGluR5 immunoreactivity (IR) in hippocampal resection tissue from pharmaco-resistant temporal lobe epilepsy (TLE) patients. IR was detected with panels of receptor subtype specific antisera in hippocampi from TLE patients without (non-HS group) and with hippocampal sclerosis (HS group) and was compared with that of non-epileptic autopsy controls (control group). By immunohistochemistry and immunoblot analysis, we found a marked increase of mGluR5 IR in hippocampi from the non-HS compared with the control group. High mGluR5 IR was most prominent in the cell bodies and apical dendrites of hippocampal principal neurons and in the dentate gyrus molecular layer. In the HS group, this increase in neuronal mGluR5 IR was even more pronounced, but owing to neuronal loss the number of mGluR5-immunoreactive neurons was reduced compared with the non-HS group. IR for mGluR1alpha was found in the cell bodies of principal neurons in all hippocampal subfields and in stratum oriens and hilar interneurons. No difference in mGluR1alpha IR was observed between neurons in both TLE groups and the control group. However, owing to neuronal loss, the number of mGluR1alpha-positive neurons was markedly reduced in the HS group. The up-regulation of mGluR5 in surviving neurons is probably a consequence rather than a cause of the epileptic seizures and may contribute to the hyperexcitability of the hippocampus in pharmaco-resistant TLE patients. Thus, our data point to a prominent role of mGluR5 in human TLE and indicate mGluR5 signalling as potential target for new anti-epileptic drugs.
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Affiliation(s)
- Robbert G E Notenboom
- Rudolf Magnus Institute of Neuroscience, Department of Pharmacology and Anatomy, University Medical Center Utrecht, Utrecht, The Netherlands.
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19
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van Eijsden P, Notenboom RGE, Wu O, de Graan PNE, van Nieuwenhuizen O, Nicolay K, Braun KPJ. In vivo 1H magnetic resonance spectroscopy, T2-weighted and diffusion-weighted MRI during lithium–pilocarpine-induced status epilepticus in the rat. Brain Res 2004; 1030:11-8. [PMID: 15567333 DOI: 10.1016/j.brainres.2004.09.025] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/24/2004] [Indexed: 10/26/2022]
Abstract
Temporal lobe epilepsy (TLE) is associated with febrile convulsions and childhood status epilepticus (SE). Since the initial precipitating injury, triggering epileptogenesis, occurs during this SE, we aimed to examine the metabolic and morphological cerebral changes during the acute phase of experimental SE noninvasively. In the rat lithium-pilocarpine model of SE, we performed quantified T(2)- and isotropic-diffusion-weighted (DW) magnetic resonance imaging (MRI) at 3 and 5 h of SE and acquired single-voxel (1)H MR spectra at 2, 4 and 6 h of SE. T(2) was globally decreased, most pronounced in the amygdala (Am) and piriformic cortex (Pi), in which also a significant decrease in apparent diffusion coefficient (ADC) was found. In contrast, ADC values increased transiently in the hippocampus (HC) and thalamus (Th). MR spectra showed a decrease in N-acetylaspartate (NAA) and choline (Cho) and an increase of lactate in a hippocampal voxel. The T(2) decrease, attributed to raised deoxyhemoglobin, and the presence of lactate both indicate a mismatch between oxygen demand and delivery. The ADC decrease, indicative of excitotoxicity, confirms that the amygdala and piriformic cortex are particularly vulnerable to lithium-pilocarpine-induced seizures. The transient ADC increase in the thalamus may reflect the breakdown of the blood-brain barrier (BBB), which is shown to occur in this region at these time points. Neuronal damage and failure of energy-dependent formation of NAA are likely causes of an observed decrease in NAA, while the decrease in Cho is possibly due to depletion of the cholinergic system. This study illustrates that relative hypoxia, excitotoxicity and concomitant neuronal damage associated with SE can be probed noninvasively with MR. These pathological phenomena are the first to contribute to the pathophysiology of spontaneous recurrent seizures in a later stage in this animal model.
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Affiliation(s)
- Pieter van Eijsden
- Department of Neurology and Neurosurgery, Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht, Utrecht, The Netherlands.
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20
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Abstract
Amyotrophic lateral sclerosis is an incurable disease in which cerebral and spinal motoneurons degenerate, causing paralysis and death within 2-5 years. One of the pathogenic factors of motoneuron death is a chronic excess of glutamate, which exceeds its removal by astrocytes, i.e. excitotoxicity. Extra glutamate uptake in the spinal cord may slow down or prevent motoneuron death. We have engineered cells over-expressing the main glutamate transporter and tested their potential to rescue motoneurons exposed to high levels of glutamate in vitro. The engineered cells protected motoneurons in a motoneuron-astrocyte co-culture at glutamate concentrations when astrocytes were no longer capable of removing glutamate. This suggests that engineered cells, introduced into the spinal column, can help remove glutamate, thereby preventing motoneuron death.
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Affiliation(s)
- Liselijn A B Wisman
- Department of Neurology, University Medical Center Utrecht, Utrecht, The Netherlands.
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21
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van Dam EJM, Kamal A, Artola A, de Graan PNE, Gispen WH, Ramakers GMJ. Group I metabotropic glutamate receptors regulate the frequency-response function of hippocampal CA1 synapses for the induction of LTP and LTD. Eur J Neurosci 2004; 19:112-8. [PMID: 14750969 DOI: 10.1111/j.1460-9568.2004.03103.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Synaptically released glutamate binds to ionotropic or metabotropic glutamate receptors. Metabotropic glutamate receptors (mGluRs) are G-protein-coupled receptors and can be divided into three subclasses (Group I-III) depending on their pharmacology and coupling to signal transduction cascades. Group I mGluRs are coupled to phospholipase C and are implicated in several important physiological processes, including activity-dependent synaptic plasticity, but their exact role in synaptic plasticity remains unclear. Synaptic plasticity can manifest itself as an increase or decrease of synaptic efficacy, referred to as long-term potentiation (LTP) and long-term depression (LTD). The likelihood, degree and direction of the change in synaptic efficacy depends on the history of the synapse and is referred to as 'metaplasticity'. We provide direct experimental evidence for an involvement of group I mGluRs in metaplasticity in CA1 hippocampal synapses. Bath application of a low concentration of the specific group I agonist 3,5-dihydroxyphenylglycine (DHPG), which does not affect basal synaptic transmission, resulted in a leftward shift of the frequency-response function for the induction of LTD and LTP in naïve synapses. DHPG resulted in the induction of LTP at frequencies which induced LTD in control slices. These alterations in the induction of LTD and LTP resemble the metaplastic changes observed in previously depressed synapses. In addition, in the presence of DHPG additional potentiation could be induced after LTP had apparently been saturated. These findings provide strong evidence for an involvement of group I mGluRs in the regulation of metaplasticity in the CA1 field of the hippocampus.
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Affiliation(s)
- Els J M van Dam
- Rudolf Magnus Institute of Neuroscience, UMC Utrecht, Universiteitsweg 100, 3584 CG Utrecht, The Netherlands
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22
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Abstract
RC3 is a neuronal calmodulin-binding protein and protein kinase C substrate that is thought to play an important regulatory role in synaptic transmission and neuronal plasticity. Two molecules known to regulate synaptic transmission and neuronal plasticity are Ca(2+) and calmodulin, and proposed mechanisms of RC3 action involve both molecules. However, physiological evidence for a role of RC3 in neuronal Ca(2+) dynamics is limited. In the current study we utilized cultured cortical neurons obtained from RC3 knockout (RC3-/-) and wildtype mice (RC3+/+) and fura-2-based microscopic Ca(2+) imaging to investigate a role for RC3 in neuronal Ca(2+) dynamics. Immunocytochemical characterization showed that the RC3-/- cultures lack RC3 immunoreactivity, whereas cultures prepared from wildtype mice showed RC3 immunoreactivity at all ages studied. RC3+/+ and RC3-/- cultures were indistinguishable with respect to neuron density, neuronal morphology, the formation of extensive neuritic networks and the presence of glial fibrillary acidic protein (GFAP)-positive astrocytes and gamma-aminobutyric acid (GABA)ergic neurons. However, the absence of RC3 in the RC3-/- neurons was found to alter neuronal Ca(2+) dynamics including baseline Ca(2+) levels measured under normal physiological conditions or after blockade of synaptic transmission, spontaneous intracellular Ca(2+) oscillations generated by network synaptic activity, and Ca(2+) responses elicited by exogenous application of N-methyl-D-aspartate (NMDA) or class I metabotropic glutamate receptor agonists. Thus, significant changes in Ca(2+) dynamics occur in cortical neurons when RC3 is absent and these changes do not involve changes in gross neuronal morphology or neuronal maturation. These data provide direct physiological evidence for a regulatory role of RC3 in neuronal Ca(2+) dynamics.
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Affiliation(s)
- Jacqueline J W van Dalen
- Division of Pharmacology and Anatomy, Rudolf Magnus Institute for Neurosciences, University Medical Center, Utrecht, The Netherlands
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23
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van Dam EJM, Ruiter B, Kamal A, Ramakers GMJ, Gispen WH, de Graan PNE. N-methyl-D-aspartate-induced long-term depression is associated with a decrease in postsynaptic protein kinase C substrate phosphorylation in rat hippocampal slices. Neurosci Lett 2002; 320:129-32. [PMID: 11852179 DOI: 10.1016/s0304-3940(02)00037-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Incubation of rat hippocampal slices with a low concentration of N-methyl-D-aspartate (NMDA; 20 microM; 3 min) elicits a form of long-term depression (LTD). We used this chemical protocol to study the involvement of pre- and postsynaptic protein kinase/phosphatase activity in NMDA receptor-dependent LTD. We determined the phosphorylation states of a pre- and a postsynaptic protein kinase C substrate, B-50/growth-associated protein 43 (GAP43) and RC3, respectively, using quantitative immunoprecipitation. NMDA incubation resulted in a 2-amino-5-phosphonovalerate-sensitive long-lasting (>60 min) decrease in synaptic efficacy and a concomitant reduction in RC3 phosphorylation. B-50/GAP43 phosphorylation was unaffected. This suggests that NMDA-LTD, in contrast to low frequency-LTD, is only associated with activation of postsynaptic protein phosphatases.
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Affiliation(s)
- Els J M van Dam
- Department of Pharmacology and Anatomy, Rudolf Magnus Institute for Neurosciences, University Medical Center Utrecht, P.O. Box 85060, 3508 AB Utrecht, The Netherlands
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