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Wang SH, Lee DS, Kim TH, Kim JE, Kang TC. Reciprocal regulation of oxidative stress and mitochondrial fission augments parvalbumin downregulation through CDK5-DRP1- and GPx1-NF-κB signaling pathways. Cell Death Dis 2024; 15:707. [PMID: 39349423 PMCID: PMC11443148 DOI: 10.1038/s41419-024-07050-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2024] [Revised: 09/01/2024] [Accepted: 09/03/2024] [Indexed: 10/02/2024]
Abstract
Loss of parvalbumin (PV) expressing neurons (PV neurons) is relevant to the underlying mechanisms of the pathogenesis of neurological and psychiatric diseases associated with the dysregulation of neuronal excitatory networks and brain metabolism. Although PV modulates mitochondrial morphology, volume and dynamics, it is largely unknown whether mitochondrial dynamics affect PV expression and what the molecular events are responsible for PV neuronal degeneration. In the present study, L-buthionine sulfoximine (BSO, an inhibitor of glutathione synthesis) did not degenerate PV neurons under physiological condition. However, BSO-induced oxidative stress decreased PV expression and facilitated cyclin-dependent kinase 5 (CDK5) tyrosine (Y) 15 phosphorylation, dynamin-related protein 1 (DRP1)-mediated mitochondrial fission and glutathione peroxidase-1 (GPx1) downregulation in PV neurons. Co-treatment of roscovitine (a CDK5 inhibitor) or mitochondrial division inhibitor-1 (Mdivi-1, an inhibitor of mitochondrial fission) attenuated BSO-induced PV downregulation. WY14643 (an inducer of mitochondrial fission) reduced PV expression without affecting CDK5 Y15 phosphorylation. Following status epilepticus (SE), CDK5 Y15 phosphorylation and mitochondrial fission were augmented in PV neurons. These were accompanied by reduced GPx1-mediated inhibition of NF-κB p65 serine (S) 536 phosphorylation. N-acetylcysteine (NAC), roscovitine and Mdivi-1 ameliorated SE-induced PV neuronal degeneration by mitigating CDK5 Y15 hyperphosphorylation, aberrant mitochondrial fragmentation and reduced GPx1-mediated NF-κB inhibition. Furthermore, SN50 (a NF-κB inhibitor) alleviated SE-induced PV neuronal degeneration, independent of dysregulation of mitochondrial fission, CDK5 hyperactivation and GPx1 downregulation. These findings provide an evidence that oxidative stress may activate CDK5-DRP1- and GPx1-NF-κB-mediated signaling pathways, which would be possible therapeutic targets for preservation of PV neurons in various diseases.
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Affiliation(s)
- Su Hyeon Wang
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, 24252, South Korea
| | - Duk-Shin Lee
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, 24252, South Korea
| | - Tae-Hyun Kim
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, 24252, South Korea
| | - Ji-Eun Kim
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, 24252, South Korea.
| | - Tae-Cheon Kang
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, 24252, South Korea.
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2
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Junghans K, Wyeth M, Buckmaster PS. Rat strain differences in seizure frequency and hilar neuron loss after systemic treatment with pilocarpine. Epilepsy Res 2024; 204:107384. [PMID: 38879905 PMCID: PMC11253724 DOI: 10.1016/j.eplepsyres.2024.107384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Revised: 05/13/2024] [Accepted: 05/29/2024] [Indexed: 06/18/2024]
Abstract
At least 3 months after systemic treatment with pilocarpine to induce status epilepticus, Long-Evans and Sprague-Dawley rats were video-EEG monitored for seizures continuously for 1 month. Rats were then perfused, hippocampi were processed for Nissl staining, and hilar neurons were quantified. Seizure frequency in Long-Evans rats was 1/10th of that in Sprague-Dawley rats, and more variable. Hilar neuron loss was also less severe in Long-Evans rats. However, there was no correlation between hilar neuron loss and seizure frequency in either strain. The low and variable seizure frequency suggests limited usefulness of pilocarpine-treated Long-Evans rats for some epilepsy experiments.
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Affiliation(s)
- Kristina Junghans
- Departments of Comparative Medicine, Stanford University, 3172 Porter Drive, Palo Alto, CA 94304-5475, USA
| | - Megan Wyeth
- Departments of Comparative Medicine, Stanford University, 3172 Porter Drive, Palo Alto, CA 94304-5475, USA.
| | - Paul S Buckmaster
- Departments of Comparative Medicine, Stanford University, 3172 Porter Drive, Palo Alto, CA 94304-5475, USA; Departments of Neurology & Neurological Sciences, Stanford University, 3172 Porter Drive, Palo Alto, CA 94304-5475, USA
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3
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Pereira MF, Shyti R, Testa G. In and out: Benchmarking in vitro, in vivo, ex vivo, and xenografting approaches for an integrative brain disease modeling pipeline. Stem Cell Reports 2024; 19:767-795. [PMID: 38865969 PMCID: PMC11390705 DOI: 10.1016/j.stemcr.2024.05.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2022] [Revised: 05/09/2024] [Accepted: 05/11/2024] [Indexed: 06/14/2024] Open
Abstract
Human cellular models and their neuronal derivatives have afforded unprecedented advances in elucidating pathogenic mechanisms of neuropsychiatric diseases. Notwithstanding their indispensable contribution, animal models remain the benchmark in neurobiological research. In an attempt to harness the best of both worlds, researchers have increasingly relied on human/animal chimeras by xenografting human cells into the animal brain. Despite the unparalleled potential of xenografting approaches in the study of the human brain, literature resources that systematically examine their significance and advantages are surprisingly lacking. We fill this gap by providing a comprehensive account of brain diseases that were thus far subjected to all three modeling approaches (transgenic rodents, in vitro human lineages, human-animal xenografting) and provide a critical appraisal of the impact of xenografting approaches for advancing our understanding of those diseases and brain development. Next, we give our perspective on integrating xenografting modeling pipeline with recent cutting-edge technological advancements.
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Affiliation(s)
- Marlene F Pereira
- Department of Experimental Oncology, European Institute of Oncology IRCCS, Via Adamello 16, 20139 Milan, Italy; Department of Oncology and Hemato-Oncology, University of Milan, Via Santa Sofia 9, 20122 Milan, Italy; Neurogenomics Centre, Human Technopole, Viale Rita Levi-Montalcini 1, 20157 Milan, Italy.
| | - Reinald Shyti
- Department of Experimental Oncology, European Institute of Oncology IRCCS, Via Adamello 16, 20139 Milan, Italy; Neurogenomics Centre, Human Technopole, Viale Rita Levi-Montalcini 1, 20157 Milan, Italy.
| | - Giuseppe Testa
- Department of Experimental Oncology, European Institute of Oncology IRCCS, Via Adamello 16, 20139 Milan, Italy; Department of Oncology and Hemato-Oncology, University of Milan, Via Santa Sofia 9, 20122 Milan, Italy; Neurogenomics Centre, Human Technopole, Viale Rita Levi-Montalcini 1, 20157 Milan, Italy.
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4
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Bertram EH. The case against secondary epileptogenesis. Epilepsy Res 2023; 198:107179. [PMID: 37336709 DOI: 10.1016/j.eplepsyres.2023.107179] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2023] [Revised: 05/11/2023] [Accepted: 06/08/2023] [Indexed: 06/21/2023]
Abstract
Secondary epileptogenesis is a theory that hypothesizes that uncontrolled seizures in people with epilepsy lead to the development of new sites of seizure onset. This process has often been cited when people experience a new seizure type after a period of poor seizure control. The theory proposes that repeated seizures induce changes in regions of the brain that are regularly recruited into the seizure. These hypothetical changes can then lead to a new, independent seizure onset zone. The concept is based on a number of clinical observations which secondary epileptogenesis could explain. However there are alternative explanations from the clinic as well as from the laboratory that call the process into question. In this review some of the observations that have been used to support the theory will be reviewed, and the many counterarguments will be presented. At this time there is little evidence to support secondary epileptogenesis and much to refute it.
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Di Sapia R, Rizzi M, Moro F, Lisi I, Caccamo A, Ravizza T, Vezzani A, Zanier ER. ECoG spiking activity and signal dimension are early predictive measures of epileptogenesis in a translational mouse model of traumatic brain injury. Neurobiol Dis 2023; 185:106251. [PMID: 37536383 DOI: 10.1016/j.nbd.2023.106251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 07/19/2023] [Accepted: 07/31/2023] [Indexed: 08/05/2023] Open
Abstract
The latency between traumatic brain injury (TBI) and the onset of epilepsy (PTE) represents an opportunity for counteracting epileptogenesis. Antiepileptogenesis trials are hampered by the lack of sensitive biomarkers that allow to enrich patient's population at-risk for PTE. We aimed to assess whether specific ECoG signals predict PTE in a clinically relevant mouse model with ∼60% epilepsy incidence. TBI was provoked in adult CD1 male mice by controlled cortical impact on the left parieto-temporal cortex, then mice were implanted with two perilesional cortical screw electrodes and two similar electrodes in the hemisphere contralateral to the lesion site. Acute seizures and spikes/sharp waves were ECoG-recorded during 1 week post-TBI. These early ECoG events were analyzed according to PTE incidence as assessed by measuring spontaneous recurrent seizures (SRS) at 5 months post-TBI. We found that incidence, number and duration of acute seizures during 3 days post-TBI were similar in PTE mice and mice not developing epilepsy (No SRS mice). Control mice with cortical electrodes (naïve, n = 5) or with electrodes and craniotomy (sham, n = 5) exhibited acute seizures but did not develop epilepsy. The daily number of spikes/sharp waves at the perilesional electrodes was increased similarly in PTE (n = 15) and No SRS (n = 8) mice vs controls (p < 0.05, n = 10) from day 2 post-injury. Differently, the daily number of spikes/sharp waves at both contralateral electrodes showed a progressive increase in PTE mice vs No SRS and control mice. In particular, spikes number was higher in PTE vs No SRS mice (p < 0.05) at 6 and 7 days post-TBI, and this measure predicted epilepsy development with high accuracy (AUC = 0.77, p = 0.03; CI 0.5830-0.9670). The cut-off value was validated in an independent cohort of TBI mice (n = 12). The daily spike number at the contralateral electrodes showed a circadian distribution in PTE mice which was not observed in No SRS mice. Analysis of non-linear dynamics at each electrode site showed changes in dimensionality during 4 days post-TBI. This measure yielded the best discrimination between PTE and No SRS mice (p < 0.01) at the cortical electrodes contralateral to injury. Data show that epileptiform activity contralateral to the lesion site has the the highest predictive value for PTE in this model reinforcing the hypothesis that the hemisphere contralateral to the lesion core may drive epileptogenic networks after TBI.
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Affiliation(s)
- Rossella Di Sapia
- Department of Acute Brain and Cardiovascular Injury, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milano, Italy
| | - Massimo Rizzi
- Department of Acute Brain and Cardiovascular Injury, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milano, Italy
| | - Federico Moro
- Department of Acute Brain and Cardiovascular Injury, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milano, Italy
| | - Ilaria Lisi
- Department of Acute Brain and Cardiovascular Injury, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milano, Italy
| | - Alessia Caccamo
- Department of Acute Brain and Cardiovascular Injury, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milano, Italy
| | - Teresa Ravizza
- Department of Acute Brain and Cardiovascular Injury, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milano, Italy
| | - Annamaria Vezzani
- Department of Acute Brain and Cardiovascular Injury, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milano, Italy.
| | - Elisa R Zanier
- Department of Acute Brain and Cardiovascular Injury, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milano, Italy.
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Komoltsev I, Salyp O, Volkova A, Bashkatova D, Shirobokova N, Frankevich S, Shalneva D, Kostyunina O, Chizhova O, Kostrukov P, Novikova M, Gulyaeva N. Posttraumatic and Idiopathic Spike-Wave Discharges in Rats: Discrimination by Morphology and Thalamus Involvement. Neurol Int 2023; 15:609-621. [PMID: 37218977 DOI: 10.3390/neurolint15020038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2023] [Revised: 04/22/2023] [Accepted: 04/25/2023] [Indexed: 05/24/2023] Open
Abstract
The possibility of epileptiform activity generation by the thalamocortical neuronal network after focal brain injuries, including traumatic brain injury (TBI), is actively debated. Presumably, posttraumatic spike-wave discharges (SWDs) involve a cortico-thalamocortical neuronal network. Differentiation of posttraumatic and idiopathic (i.e., spontaneously generated) SWDs is imperative for understanding posttraumatic epileptogenic mechanisms. Experiments were performed on male Sprague-Dawley rats with electrodes implanted into the somatosensory cortex and the thalamic ventral posterolateral nucleus. Local field potentials were recorded for 7 days before and 7 days after TBI (lateral fluid percussion injury, 2.5 atm). The morphology of 365 SWDs (89 idiopathic before craniotomy, and 262 posttraumatic that appeared only after TBI) and their appearance in the thalamus were analyzed. The occurrence of SWDs in the thalamus determined their spike-wave form and bilateral lateralization in the neocortex. Posttraumatic discharges were characterized by more "mature" characteristics as compared to spontaneously generated discharges: higher proportions of bilateral spreading, well-defined spike-wave form, and thalamus involvement. Based on SWD parameters, the etiology could be established with an accuracy of 75% (AUC 0.79). Our results support the hypothesis that the formation of posttraumatic SWDs involves a cortico-thalamocortical neuronal network. The results form a basis for further research of mechanisms associated with posttraumatic epileptiform activity and epileptogenesis.
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Affiliation(s)
- Ilia Komoltsev
- Department of Functional Biochemistry of the Nervous System, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow 117485, Russia
- Moscow Research and Clinical Center for Neuropsychiatry, Moscow 115419, Russia
| | - Olga Salyp
- Department of Functional Biochemistry of the Nervous System, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow 117485, Russia
| | - Aleksandra Volkova
- Department of Functional Biochemistry of the Nervous System, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow 117485, Russia
| | - Daria Bashkatova
- Department of Functional Biochemistry of the Nervous System, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow 117485, Russia
| | - Natalia Shirobokova
- Department of Functional Biochemistry of the Nervous System, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow 117485, Russia
| | - Stepan Frankevich
- Department of Functional Biochemistry of the Nervous System, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow 117485, Russia
- Moscow Research and Clinical Center for Neuropsychiatry, Moscow 115419, Russia
| | - Daria Shalneva
- Department of Functional Biochemistry of the Nervous System, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow 117485, Russia
| | - Olga Kostyunina
- Department of Functional Biochemistry of the Nervous System, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow 117485, Russia
| | - Olesya Chizhova
- Department of Functional Biochemistry of the Nervous System, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow 117485, Russia
| | - Pavel Kostrukov
- Department of Functional Biochemistry of the Nervous System, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow 117485, Russia
| | - Margarita Novikova
- Department of Functional Biochemistry of the Nervous System, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow 117485, Russia
| | - Natalia Gulyaeva
- Department of Functional Biochemistry of the Nervous System, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow 117485, Russia
- Moscow Research and Clinical Center for Neuropsychiatry, Moscow 115419, Russia
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Zahra A, Sun Y, Aloysius N, Zhang L. Convulsive behaviors of spontaneous recurrent seizures in a mouse model of extended hippocampal kindling. Front Behav Neurosci 2022; 16:1076718. [PMID: 36620863 PMCID: PMC9816810 DOI: 10.3389/fnbeh.2022.1076718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Accepted: 12/12/2022] [Indexed: 12/24/2022] Open
Abstract
Growing studies indicate that vigilance states and circadian rhythms can influence seizure occurrence in patients with epilepsy and rodent models of epilepsy. Electrical kindling, referred to brief, repeated stimulations of a limbic structure, is a commonly used model of temporal lobe epilepsy. Kindling via the classic protocol lasting a few weeks does not generally induce spontaneous recurrent seizures (SRS), but extended kindling that applies over the course of a few months has shown to induce SRS in several animal species. Kindling-induced SRS in monkeys and cats were observed mainly during resting wakefulness or sleep, but the behavioral activities associated with SRS in rodent models of extended kindling remain unknown. We aimed to add information in this area using a mouse model of extended hippocampal kindling. Middle-aged C57 black mice experienced ≥80 hippocampal stimulations (delivered twice daily) and then underwent continuous 24 h electroencephalography (EEG)-video monitoring for SRS detection. SRS were recognized by EEG discharges and associated motor seizures. The five stages of the modified Racine scale for mice were used to score motor seizure severities. Seizure-preceding behaviors were assessed in a 3 min period prior to seizure onset and categorized as active and inactive. Three main observations emerged from the present analysis. (1) SRS were found to predominantly manifest as generalized (stage 3-5) motor seizures in association with tail erection or Straub tail. (2) SRS occurrences were not significantly altered by the light on/off cycle. (3) Generalized (stage 3-5) motor seizures were mainly preceded by inactive behaviors such as immobility, standing still, or apparent sleep without evident volitional movement. Considering deeper subcortical structures implicated in genesis of tail erection in other seizure models, we postulate that genesis of generalized motor seizures in extended kindled mice may involve deeper subcortical structures. Our present data together with previous findings from post-status epilepticus models support the notion that ambient cage behaviors are strong influencing factors of SRS occurrence in rodent models of temporal lobe epilepsy.
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Affiliation(s)
- Anya Zahra
- Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | - Yuqing Sun
- Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | - Nancy Aloysius
- Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | - Liang Zhang
- Krembil Research Institute, University Health Network, Toronto, ON, Canada,Division of Neurology, Department of Medicine, University of Toronto, Toronto, ON, Canada,*Correspondence: Liang Zhang,
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Dohm-Hansen S, Donoso F, Lucassen PJ, Clarke G, Nolan YM. The gut microbiome and adult hippocampal neurogenesis: A new focal point for epilepsy? Neurobiol Dis 2022; 170:105746. [DOI: 10.1016/j.nbd.2022.105746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2021] [Revised: 04/13/2022] [Accepted: 04/29/2022] [Indexed: 02/07/2023] Open
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Gage M, Putra M, Wachter L, Dishman K, Gard M, Gomez-Estrada C, Thippeswamy T. Saracatinib, a Src Tyrosine Kinase Inhibitor, as a Disease Modifier in the Rat DFP Model: Sex Differences, Neurobehavior, Gliosis, Neurodegeneration, and Nitro-Oxidative Stress. Antioxidants (Basel) 2021; 11:61. [PMID: 35052568 PMCID: PMC8773289 DOI: 10.3390/antiox11010061] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Revised: 12/17/2021] [Accepted: 12/23/2021] [Indexed: 12/13/2022] Open
Abstract
Diisopropylfluorophosphate (DFP), an organophosphate nerve agent (OPNA), exposure causes status epilepticus (SE) and epileptogenesis. In this study, we tested the protective effects of saracatinib (AZD0530), a Src kinase inhibitor, in mixed-sex or male-only Sprague Dawley rats exposed to 4-5 mg/kg DFP followed by 2 mg/kg atropine and 25 mg/kg 2-pralidoxime. Midazolam (3 mg/kg) was given to the mixed-sex cohort (1 h post-DFP) and male-only cohort (~30 min post-DFP). Saracatinib (20 mg/kg, oral, daily for 7 days) or vehicle was given two hours later and euthanized eight days or ten weeks post-DFP. Brain immunohistochemistry (IHC) showed increased microgliosis, astrogliosis, and neurodegeneration in DFP-treated animals. In the 10-week post-DFP male-only group, there were no significant differences between groups in the novel object recognition, Morris water maze, rotarod, or forced swim test. Brain IHC revealed significant mitigation by saracatinib in contrast to vehicle-treated DFP animals in microgliosis, astrogliosis, neurodegeneration, and nitro-oxidative stressors, such as inducible nitric oxide synthase, GP91phox, and 3-Nitrotyrosine. These findings suggest the protective effects of saracatinib on brain pathology seem to depend on the initial SE severity. Further studies on dose optimization, including extended treatment regimen depending on the SE severity, are required to determine its disease-modifying potential in OPNA models.
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Affiliation(s)
| | | | | | | | | | | | - Thimmasettappa Thippeswamy
- Department of Biomedical Sciences and Interdepartmental Neuroscience Program, Iowa State University, Ames, IA 50011, USA; (M.G.); (M.P.); (L.W.); (K.D.); (M.G.); (C.G.-E.)
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Perulli M, Battista A, Sivo S, Turrini I, Musto E, Quintiliani M, Gambardella ML, Contaldo I, Veredice C, Mercuri EM, Lanza GA, Dravet C, Delogu AB, Battaglia DI. Heart rate variability alterations in Dravet Syndrome: The role of status epilepticus and a possible association with mortality risk. Seizure 2021; 94:129-135. [PMID: 34896816 DOI: 10.1016/j.seizure.2021.11.023] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 11/02/2021] [Accepted: 11/26/2021] [Indexed: 11/15/2022] Open
Abstract
PURPOSE Preliminary data suggest that patients with Dravet Syndrome (DS) have a reduced heart rate variability (HRV). This seems particularly evident in patients who experienced sudden unexpected death in epilepsy (SUDEP). This study aims at confirming these findings in a larger cohort and at defining clinical, genetic or electroencephalographic predictors of HRV impairment in DS patients. METHODS DS patients followed at our Institution performed a 24h-ECG Holter to derive HRV parameters. We used as control population patients with epilepsy (PWEs) and healthy controls (HCs). In DS patients, we assessed the impact of different clinical, neurophysiological and genetic features on HRV alterations through multiple linear regression. After a mean follow-up of 7.4 ± 3.2 years since the HRV assessment, all DS patients were contacted to record death or life-threatening events. RESULTS 56 DS patients had a significantly reduced HRV compared to both HCs and PWEs. A recent history of status epilepticus (SE) was the only significant predictor of lower HRV in the multivariate analysis. At follow-up, only one patient died; her HRV was lower than that of all the controls and was in the low range for DS patients. CONCLUSION We describe for the first time an association between SE and HRV alterations in DS. Further studies on other SCN1A-related phenotypes and other epilepsies with frequent SE will help clarify this finding. Compared to the literature, our cohort showed better HRV and lower mortality. Although limited, this observation reinforces the role of HRV as a biomarker for mortality risk in DS.
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Affiliation(s)
- Marco Perulli
- Pediatric Neurology, Dipartimento di Scienze della Salute della Donna, del Bambino e di Sanità Pubblica, Fondazione, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy; Dipartimento di Scienze della Vita e Sanità Pubblica, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Andrea Battista
- Pediatrics, Dipartimento di Scienze della Salute della Donna, del Bambino e di Sanità Pubblica, Fondazione, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy; Dipartimento di Scienze della Vita e Sanità Pubblica, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Serena Sivo
- Pediatric Neurology, Dipartimento di Scienze della Salute della Donna, del Bambino e di Sanità Pubblica, Fondazione, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy; Dipartimento di Scienze della Vita e Sanità Pubblica, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Ida Turrini
- Pediatric Neurology, Dipartimento di Scienze della Salute della Donna, del Bambino e di Sanità Pubblica, Fondazione, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy; Dipartimento di Scienze della Vita e Sanità Pubblica, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Elisa Musto
- Pediatric Neurology, Dipartimento di Scienze della Salute della Donna, del Bambino e di Sanità Pubblica, Fondazione, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy; Dipartimento di Scienze della Vita e Sanità Pubblica, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Michela Quintiliani
- Pediatric Neurology, Dipartimento di Scienze della Salute della Donna, del Bambino e di Sanità Pubblica, Fondazione, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy; Dipartimento di Scienze della Vita e Sanità Pubblica, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Maria Luigia Gambardella
- Pediatric Neurology, Dipartimento di Scienze della Salute della Donna, del Bambino e di Sanità Pubblica, Fondazione, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy; Dipartimento di Scienze della Vita e Sanità Pubblica, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Ilaria Contaldo
- Pediatric Neurology, Dipartimento di Scienze della Salute della Donna, del Bambino e di Sanità Pubblica, Fondazione, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
| | - Chiara Veredice
- Pediatric Neurology, Dipartimento di Scienze della Salute della Donna, del Bambino e di Sanità Pubblica, Fondazione, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy; Dipartimento di Scienze della Vita e Sanità Pubblica, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Eugenio Maria Mercuri
- Pediatric Neurology, Dipartimento di Scienze della Salute della Donna, del Bambino e di Sanità Pubblica, Fondazione, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy; Dipartimento di Scienze della Vita e Sanità Pubblica, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Gaetano Antonio Lanza
- Cardiology, Dipartimento di Scienze Cardiovascolari e Toraciche, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy; Dipartimento di Scienze cardiovascolari e pneumologiche, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Charlotte Dravet
- Pediatric Neurology, Dipartimento di Scienze della Salute della Donna, del Bambino e di Sanità Pubblica, Fondazione, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
| | - Angelica Bibiana Delogu
- Pediatrics, Dipartimento di Scienze della Salute della Donna, del Bambino e di Sanità Pubblica, Fondazione, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy; Dipartimento di Scienze della Vita e Sanità Pubblica, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Domenica Immacolata Battaglia
- Pediatric Neurology, Dipartimento di Scienze della Salute della Donna, del Bambino e di Sanità Pubblica, Fondazione, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy; Dipartimento di Scienze della Vita e Sanità Pubblica, Università Cattolica del Sacro Cuore, Rome, Italy.
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11
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Zimmer TS, David B, Broekaart DWM, Schidlowski M, Ruffolo G, Korotkov A, van der Wel NN, van Rijen PC, Mühlebner A, van Hecke W, Baayen JC, Idema S, François L, van Eyll J, Dedeurwaerdere S, Kessels HW, Surges R, Rüber T, Gorter JA, Mills JD, van Vliet EA, Aronica E. Seizure-mediated iron accumulation and dysregulated iron metabolism after status epilepticus and in temporal lobe epilepsy. Acta Neuropathol 2021; 142:729-759. [PMID: 34292399 PMCID: PMC8423709 DOI: 10.1007/s00401-021-02348-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 07/02/2021] [Accepted: 07/12/2021] [Indexed: 12/12/2022]
Abstract
Neuronal dysfunction due to iron accumulation in conjunction with reactive oxygen species (ROS) could represent an important, yet underappreciated, component of the epileptogenic process. However, to date, alterations in iron metabolism in the epileptogenic brain have not been addressed in detail. Iron-related neuropathology and antioxidant metabolic processes were investigated in resected brain tissue from patients with temporal lobe epilepsy and hippocampal sclerosis (TLE-HS), post-mortem brain tissue from patients who died after status epilepticus (SE) as well as brain tissue from the electrically induced SE rat model of TLE. Magnetic susceptibility of the presumed seizure-onset zone from three patients with focal epilepsy was compared during and after seizure activity. Finally, the cellular effects of iron overload were studied in vitro using an acute mouse hippocampal slice preparation and cultured human fetal astrocytes. While iron-accumulating neurons had a pyknotic morphology, astrocytes appeared to acquire iron-sequestrating capacity as indicated by prominent ferritin expression and iron retention in the hippocampus of patients with SE or TLE. Interictal to postictal comparison revealed increased magnetic susceptibility in the seizure-onset zone of epilepsy patients. Post-SE rats had consistently higher hippocampal iron levels during the acute and chronic phase (when spontaneous recurrent seizures are evident). In vitro, in acute slices that were exposed to iron, neurons readily took up iron, which was exacerbated by induced epileptiform activity. Human astrocyte cultures challenged with iron and ROS increased their antioxidant and iron-binding capacity, but simultaneously developed a pro-inflammatory phenotype upon chronic exposure. These data suggest that seizure-mediated, chronic neuronal iron uptake might play a role in neuronal dysfunction/loss in TLE-HS. On the other hand, astrocytes sequester iron, specifically in chronic epilepsy. This function might transform astrocytes into a highly resistant, pro-inflammatory phenotype potentially contributing to pro-epileptogenic inflammatory processes.
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Affiliation(s)
- Till S Zimmer
- Department of (Neuro)Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam Neuroscience, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
| | - Bastian David
- Department of Epileptology, University Hospital Bonn, Bonn, Germany
| | - Diede W M Broekaart
- Department of (Neuro)Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam Neuroscience, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
| | - Martin Schidlowski
- Department of Epileptology, University Hospital Bonn, Bonn, Germany
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Gabriele Ruffolo
- Laboratory affiliated to Istituto Pasteur Italia, Department of Physiology and Pharmacology, University of Rome Sapienza, Rome, Italy
| | - Anatoly Korotkov
- Department of (Neuro)Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam Neuroscience, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
| | - Nicole N van der Wel
- Department Cell Biology and Histology, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
- Department Electron Microscopy Center Amsterdam, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Peter C van Rijen
- Department of Neurosurgery, Brain Centre, Rudolf Magnus Institute for Neuroscience, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Angelika Mühlebner
- Department of (Neuro)Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam Neuroscience, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
- Department of Pathology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Wim van Hecke
- Department of Pathology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Johannes C Baayen
- Department of Neurosurgery, Amsterdam Neuroscience, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Sander Idema
- Department of Neurosurgery, Amsterdam Neuroscience, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Liesbeth François
- Neurosciences Therapeutic Area, UCB Pharma, Braine-l'Alleud, Belgium
| | - Jonathan van Eyll
- Neurosciences Therapeutic Area, UCB Pharma, Braine-l'Alleud, Belgium
| | | | - Helmut W Kessels
- Center for Neuroscience, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - Rainer Surges
- Department of Epileptology, University Hospital Bonn, Bonn, Germany
| | - Theodor Rüber
- Department of Epileptology, University Hospital Bonn, Bonn, Germany
| | - Jan A Gorter
- Center for Neuroscience, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - James D Mills
- Department of (Neuro)Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam Neuroscience, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
- Department of Clinical and Experimental Epilepsy, UCL, London, UK
- Chalfont Centre for Epilepsy, Chalfont St Peter, UK
| | - Erwin A van Vliet
- Department of (Neuro)Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam Neuroscience, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
- Center for Neuroscience, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - Eleonora Aronica
- Department of (Neuro)Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam Neuroscience, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands.
- Stichting Epilepsie Instellingen Nederland (SEIN), Heemstede, The Netherlands.
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12
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de Curtis M, Rossetti AO, Verde DV, van Vliet EA, Ekdahl CT. Brain pathology in focal status epilepticus: evidence from experimental models. Neurosci Biobehav Rev 2021; 131:834-846. [PMID: 34517036 DOI: 10.1016/j.neubiorev.2021.09.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 09/02/2021] [Accepted: 09/05/2021] [Indexed: 12/01/2022]
Abstract
Status Epilepticus (SE) is often a neurological emergency characterized by abnormally sustained, longer than habitual seizures. The new ILAE classification reports that SE "…can have long-term consequences including neuronal death, neuronal injury…depending on the type and duration of seizures". While it is accepted that generalized convulsive SE exerts detrimental effects on the brain, it is not clear if other forms of SE, such as focal non-convulsive SE, leads to brain pathology and contributes to long-term deficits in patients. With the available clinical and experimental data, it is hard to discriminate the specific action of the underlying SE etiologies from that exerted by epileptiform activity. This information is highly relevant in the clinic for better treatment stratification, which may include both medical and surgical intervention for seizure control. Here we review experimental studies of focal SE, with an emphasis on focal non-convulsive SE. We present a repertoire of brain pathologies observed in the most commonly used animal models and attempt to establish a link between experimental findings and human condition(s). The extensive literature on focal SE animal models suggest that the current approaches have significant limitations in terms of translatability of the findings to the clinic. We highlight the need for a more stringent description of SE features and brain pathology in experimental studies in animal models, to improve the accuracy in predicting clinical translation.
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Affiliation(s)
- Marco de Curtis
- Epilepsy Unit, Fondazione IRCCS Istituto NeurologicoCarlo Besta, Milano, Italy.
| | - Andrea O Rossetti
- Department of Clinical Neuroscience, University Hospital (CHUV) and University of Lausanne, Lausanne, Switzerland
| | - Diogo Vila Verde
- Epilepsy Unit, Fondazione IRCCS Istituto NeurologicoCarlo Besta, Milano, Italy
| | - Erwin A van Vliet
- Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, Science Park 904, P.O. Box 94246, 1090 GE, Amsterdam, the Netherlands; Amsterdam UMC, University of Amsterdam, Department of (Neuro)Pathology, Amsterdam Neuroscience, Meibergdreef 9, Amsterdam, the Netherlands
| | - Christine T Ekdahl
- Division of Clinical Neurophysiology, Lund University, Sweden; Lund Epilepsy Center, Dept Clinical Sciences, Lund University, Sweden
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13
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Pitkänen A, Paananen T, Kyyriäinen J, Das Gupta S, Heiskanen M, Vuokila N, Bañuelos-Cabrera I, Lapinlampi N, Kajevu N, Andrade P, Ciszek R, Lara-Valderrábano L, Ekolle Ndode-Ekane X, Puhakka N. Biomarkers for posttraumatic epilepsy. Epilepsy Behav 2021; 121:107080. [PMID: 32317161 DOI: 10.1016/j.yebeh.2020.107080] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 03/26/2020] [Accepted: 03/30/2020] [Indexed: 12/17/2022]
Abstract
A biomarker is a characteristic that can be objectively measured as an indicator of normal biologic processes, pathogenic processes, or responses to an exposure or intervention, including therapeutic interventions. Biomarker modalities include molecular, histologic, radiographic, or physiologic characteristics. To improve the understanding and use of biomarker terminology in biomedical research, clinical practice, and medical product development, the Food and Drug Administration (FDA)-National Institutes of Health (NIH) Joint Leadership Council developed the BEST Resource (Biomarkers, EndpointS, and other Tools). The seven BEST biomarker categories include the following: (a) susceptibility/risk biomarkers, (b) diagnostic biomarkers, (c) monitoring biomarkers, (d) prognostic biomarkers, (e) predictive biomarkers, (f) pharmacodynamic/response biomarkers, and (g) safety biomarkers. We hypothesize some potential overlap between the reported biomarkers of traumatic brain injury (TBI), epilepsy, and posttraumatic epilepsy (PTE). Here, we tested this hypothesis by reviewing studies focusing on biomarker discovery for posttraumatic epileptogenesis and epilepsy. The biomarker modalities reviewed here include plasma/serum and cerebrospinal fluid molecular biomarkers, imaging biomarkers, and electrophysiologic biomarkers. Most of the reported biomarkers have an area under the receiver operating characteristic curve greater than 0.800, suggesting both high sensitivity and high specificity. Our results revealed little overlap in the biomarker candidates between TBI, epilepsy, and PTE. In addition to using single parameters as biomarkers, machine learning approaches have highlighted the potential for utilizing patterns of markers as biomarkers. Although published data suggest the possibility of identifying biomarkers for PTE, we are still in the early phase of the development curve. Many of the seven biomarker categories lack PTE-related biomarkers. Thus, further exploration using proper, statistically powered, and standardized study designs with validation cohorts, and by developing and applying novel analytical methods, is needed for PTE biomarker discovery.
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Affiliation(s)
- Asla Pitkänen
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, PO Box 1627, FIN-70211 Kuopio, Finland.
| | - Tomi Paananen
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, PO Box 1627, FIN-70211 Kuopio, Finland
| | - Jenni Kyyriäinen
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, PO Box 1627, FIN-70211 Kuopio, Finland
| | - Shalini Das Gupta
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, PO Box 1627, FIN-70211 Kuopio, Finland
| | - Mette Heiskanen
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, PO Box 1627, FIN-70211 Kuopio, Finland
| | - Niina Vuokila
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, PO Box 1627, FIN-70211 Kuopio, Finland
| | - Ivette Bañuelos-Cabrera
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, PO Box 1627, FIN-70211 Kuopio, Finland
| | - Niina Lapinlampi
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, PO Box 1627, FIN-70211 Kuopio, Finland
| | - Natallie Kajevu
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, PO Box 1627, FIN-70211 Kuopio, Finland
| | - Pedro Andrade
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, PO Box 1627, FIN-70211 Kuopio, Finland
| | - Robert Ciszek
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, PO Box 1627, FIN-70211 Kuopio, Finland
| | - Leonardo Lara-Valderrábano
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, PO Box 1627, FIN-70211 Kuopio, Finland
| | - Xavier Ekolle Ndode-Ekane
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, PO Box 1627, FIN-70211 Kuopio, Finland
| | - Noora Puhakka
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, PO Box 1627, FIN-70211 Kuopio, Finland
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14
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Carulli D, de Winter F, Verhaagen J. Semaphorins in Adult Nervous System Plasticity and Disease. Front Synaptic Neurosci 2021; 13:672891. [PMID: 34045951 PMCID: PMC8148045 DOI: 10.3389/fnsyn.2021.672891] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 04/12/2021] [Indexed: 12/13/2022] Open
Abstract
Semaphorins, originally discovered as guidance cues for developing axons, are involved in many processes that shape the nervous system during development, from neuronal proliferation and migration to neuritogenesis and synapse formation. Interestingly, the expression of many Semaphorins persists after development. For instance, Semaphorin 3A is a component of perineuronal nets, the extracellular matrix structures enwrapping certain types of neurons in the adult CNS, which contribute to the closure of the critical period for plasticity. Semaphorin 3G and 4C play a crucial role in the control of adult hippocampal connectivity and memory processes, and Semaphorin 5A and 7A regulate adult neurogenesis. This evidence points to a role of Semaphorins in the regulation of adult neuronal plasticity. In this review, we address the distribution of Semaphorins in the adult nervous system and we discuss their function in physiological and pathological processes.
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Affiliation(s)
- Daniela Carulli
- Laboratory for Neuroregeneration, Netherlands Institute for Neuroscience, Royal Academy of Arts and Sciences, Amsterdam, Netherlands
- Department of Neuroscience Rita Levi-Montalcini and Neuroscience Institute Cavalieri Ottolenghi, University of Turin, Turin, Italy
| | - Fred de Winter
- Laboratory for Neuroregeneration, Netherlands Institute for Neuroscience, Royal Academy of Arts and Sciences, Amsterdam, Netherlands
| | - Joost Verhaagen
- Laboratory for Neuroregeneration, Netherlands Institute for Neuroscience, Royal Academy of Arts and Sciences, Amsterdam, Netherlands
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15
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Kohek SRB, Foresti ML, Blanco MM, Cavarsan CF, da Silva CS, Mello LE. Anxious Profile Influences Behavioral and Immunohistological Findings in the Pilocarpine Model of Epilepsy. Front Pharmacol 2021; 12:640715. [PMID: 34025410 PMCID: PMC8132119 DOI: 10.3389/fphar.2021.640715] [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: 12/11/2020] [Accepted: 03/22/2021] [Indexed: 12/01/2022] Open
Abstract
Anxiety and epilepsy have a complex bidirectional relationship, where a depressive/anxious condition is a factor that can trigger seizures which in turn can aggravate the depressive/anxious condition. In addition, brain structures such as the hippocampus and amygdala might have a critical relevance in both epilepsy and anxiety. The aim of the present work was to investigate the influence of different anxious profiles to epileptogenesis. Initially, animals were screened through the elevated plus-maze anxiety test, and then seizure development was evaluated using the pilocarpine model of epilepsy. There were no differences in the susceptibility to status epilepticus, mortality rate or frequency of spontaneous recurrent seizures between animals characterized as anxious as compared to the non-anxious animals. Next, we evaluated immunohistological patterns related to seizures and anxiety in various related brain areas. Despite a decrease in the density of neuropeptide Y and parvalbumin expression in epileptic animals, those presenting greater neuropeptide Y immunoreactivity in various brain regions, also showed higher spontaneous recurrent seizures frequency. Differences on the anxious profile showed to interfere with some of these findings in some regions. In addition, animals that were injected with pilocarpine, but did not develop status epilepticus, had behavioral and neuroanatomical alterations as compared to control animals, indicating its importance as an additional tool for investigating the heterogeneity of the epileptogenic response after an initial insult. This study allowed to better understand the association between anxiety and temporal lobe epilepsy and might allow for therapeutic targets to be developed to minimize the negative impacts associated with it.
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Affiliation(s)
| | | | | | - Clarissa Fantin Cavarsan
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI, United States.,George and Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI, United States
| | | | - Luiz E Mello
- Physiology Department, Universidade Federal de São Paulo, São Paulo, Brazil.,Instituto D' Or de Pesquisa e Ensino, Rio de Janeiro, Brazil
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16
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The Kainic Acid Models of Temporal Lobe Epilepsy. eNeuro 2021; 8:ENEURO.0337-20.2021. [PMID: 33658312 PMCID: PMC8174050 DOI: 10.1523/eneuro.0337-20.2021] [Citation(s) in RCA: 74] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 01/14/2021] [Accepted: 01/24/2021] [Indexed: 12/14/2022] Open
Abstract
Experimental models of epilepsy are useful to identify potential mechanisms of epileptogenesis, seizure genesis, comorbidities, and treatment efficacy. The kainic acid (KA) model is one of the most commonly used. Several modes of administration of KA exist, each producing different effects in a strain-, species-, gender-, and age-dependent manner. In this review, we discuss the advantages and limitations of the various forms of KA administration (systemic, intrahippocampal, and intranasal), as well as the histologic, electrophysiological, and behavioral outcomes in different strains and species. We attempt a personal perspective and discuss areas where work is needed. The diversity of KA models and their outcomes offers researchers a rich palette of phenotypes, which may be relevant to specific traits found in patients with temporal lobe epilepsy.
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17
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Wyeth M, Nagendran M, Buckmaster PS. Ictal onset sites and γ-aminobutyric acidergic neuron loss in epileptic pilocarpine-treated rats. Epilepsia 2020; 61:856-867. [PMID: 32242932 DOI: 10.1111/epi.16490] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 02/28/2020] [Accepted: 03/04/2020] [Indexed: 01/07/2023]
Abstract
OBJECTIVE The present study tested whether ictal onset sites are regions of more severe interneuron loss in epileptic pilocarpine-treated rats, a model of human temporal lobe epilepsy. METHODS Local field potential recordings were evaluated to identify ictal onset sites. Electrode sites were visualized in Nissl-stained sections. Adjacent sections were processed with proximity ligation in situ hybridization for glutamic acid decarboxylase 2 (Gad2). Gad2 neuron profile numbers at ictal onset sites were compared to contralateral regions. Other sections were processed with immunocytochemistry for reelin or nitric oxide synthase (NOS), which labeled major subtypes of granule cell layer-associated interneurons. Stereology was used to estimate numbers of reelin and NOS granule cell layer-associated interneurons per hippocampus. RESULTS Ictal onset sites varied between and within rats but were mostly in the ventral hippocampus and were frequently bilateral. There was no conclusive evidence of more severe Gad2 neuron profile loss at sites of earliest seizure activity compared to contralateral regions. Numbers of granule cell layer-associated NOS neurons were reduced in the ventral hippocampus. SIGNIFICANCE In epileptic pilocarpine-treated rats, ictal onset sites were mostly in the ventral hippocampus, where there was loss of granule cell layer-associated NOS interneurons. These findings suggest the hypothesis that loss of granule cell layer-associated NOS interneurons in the ventral hippocampus is a mechanism of temporal lobe epilepsy.
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Affiliation(s)
- Megan Wyeth
- Department of Comparative Medicine, Stanford University, Stanford, California
| | - Monica Nagendran
- Department of Medicine-Pulmonary and Critical Care, Stanford University, Stanford, California
| | - Paul S Buckmaster
- Department of Comparative Medicine, Stanford University, Stanford, California.,Department of Neurology & Neurological Sciences, Stanford University, Stanford, California
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18
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Chauvière L. Potential causes of cognitive alterations in temporal lobe epilepsy. Behav Brain Res 2020; 378:112310. [DOI: 10.1016/j.bbr.2019.112310] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 10/15/2019] [Accepted: 10/15/2019] [Indexed: 12/11/2022]
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19
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Korotkov A, Broekaart DWM, Banchaewa L, Pustjens B, van Scheppingen J, Anink JJ, Baayen JC, Idema S, Gorter JA, van Vliet EA, Aronica E. microRNA-132 is overexpressed in glia in temporal lobe epilepsy and reduces the expression of pro-epileptogenic factors in human cultured astrocytes. Glia 2019; 68:60-75. [PMID: 31408236 PMCID: PMC6899748 DOI: 10.1002/glia.23700] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2019] [Revised: 07/29/2019] [Accepted: 07/30/2019] [Indexed: 12/26/2022]
Abstract
Temporal lobe epilepsy (TLE) is a chronic neurological disease in humans, which is refractory to pharmacological treatment in about 30% of the patients. Reactive glial cells are thought to play a major role during the development of epilepsy (epileptogenesis) via regulation of brain inflammation and remodeling of the extracellular matrix (ECM). These processes can be regulated by microRNAs (miRs), a class of small non‐coding RNAs, which can control entire gene networks at a post‐transcriptional level. The expression of miRs is known to change dynamically during epileptogenesis. miR‐132 is one of the most commonly upregulated miRs in animal TLE models with important roles shown in neurons. However, the possible role of miR‐132 in glia remains largely unknown. The aim of this study was to characterize the cell‐type specific expression of miR‐132 in the hippocampus of patients with TLE and during epileptogenesis in a rat TLE model. Furthermore, the potential role of miR‐132 was investigated by transfection of human primary cultured astrocytes that were stimulated with the cytokines IL‐1β or TGF‐β1. We showed an increased expression of miR‐132 in the human and rat epileptogenic hippocampus, particularly in glial cells. Transfection of miR‐132 in human primary astrocytes reduced the expression of pro‐epileptogenic COX‐2, IL‐1β, TGF‐β2, CCL2, and MMP3. This suggests that miR‐132, particularly in astrocytes, represents a potential therapeutic target that warrants further in vivo investigation.
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Affiliation(s)
- Anatoly Korotkov
- Amsterdam UMC, University of Amsterdam, Department of (Neuro)Pathology, Amsterdam Neuroscience, Meibergdreef 9, Amsterdam, the Netherlands
| | - Diede W M Broekaart
- Amsterdam UMC, University of Amsterdam, Department of (Neuro)Pathology, Amsterdam Neuroscience, Meibergdreef 9, Amsterdam, the Netherlands
| | - Leyla Banchaewa
- Amsterdam UMC, University of Amsterdam, Department of (Neuro)Pathology, Amsterdam Neuroscience, Meibergdreef 9, Amsterdam, the Netherlands
| | - Ben Pustjens
- Amsterdam UMC, University of Amsterdam, Department of (Neuro)Pathology, Amsterdam Neuroscience, Meibergdreef 9, Amsterdam, the Netherlands
| | - Jackelien van Scheppingen
- Amsterdam UMC, University of Amsterdam, Department of (Neuro)Pathology, Amsterdam Neuroscience, Meibergdreef 9, Amsterdam, the Netherlands
| | - Jasper J Anink
- Amsterdam UMC, University of Amsterdam, Department of (Neuro)Pathology, Amsterdam Neuroscience, Meibergdreef 9, Amsterdam, the Netherlands
| | - Johannes C Baayen
- Amsterdam UMC, Vrije Universiteit Amsterdam, Department of Neurosurgery, Amsterdam Neuroscience, De Boelelaan 1117, Amsterdam, the Netherlands
| | - Sander Idema
- Amsterdam UMC, Vrije Universiteit Amsterdam, Department of Neurosurgery, Amsterdam Neuroscience, De Boelelaan 1117, Amsterdam, the Netherlands
| | - Jan A Gorter
- Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, Amsterdam, the Netherlands
| | - Erwin A van Vliet
- Amsterdam UMC, University of Amsterdam, Department of (Neuro)Pathology, Amsterdam Neuroscience, Meibergdreef 9, Amsterdam, the Netherlands.,Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, Amsterdam, the Netherlands
| | - Eleonora Aronica
- Amsterdam UMC, University of Amsterdam, Department of (Neuro)Pathology, Amsterdam Neuroscience, Meibergdreef 9, Amsterdam, the Netherlands.,Stichting Epilepsie Instellingen Nederland (SEIN), Heemstede, the Netherlands
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20
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Targeting Seizure-Induced Neurogenesis in a Clinically Relevant Time Period Leads to Transient But Not Persistent Seizure Reduction. J Neurosci 2019; 39:7019-7028. [PMID: 31308098 DOI: 10.1523/jneurosci.0920-19.2019] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 06/18/2019] [Accepted: 06/20/2019] [Indexed: 11/21/2022] Open
Abstract
Mesial temporal lobe epilepsy (mTLE), the most common form of medically refractory epilepsy in adults, is usually associated with hippocampal pathophysiology. Using rodent models of mTLE, many studies including work from our laboratory have shown that new neurons born around the onset of severe acute seizures known as status epilepticus (SE) are crucial for the process of epileptogenesis and targeting seizure-induced neurogenesis either genetically or pharmacologically can impact the frequency of chronic seizures. However, these studies are limited in their clinical relevance as none of them determines the potential of blocking new neurons generated after the epileptogenic insult to alleviate the development of chronic seizures. Therefore, using a pilocarpine-induced SE model of mTLE in mice of either sex, we show that >4 weeks of continuous and concurrent ablation of seizure-induced neurogenesis after SE can reduce the formation of spontaneous recurrent seizures by 65%. We also found that blocking post-SE neurogenesis does not lead to long-term seizure reduction as the effect was observed only transiently for 10 d with >4 weeks of continuous and concurrent ablation of seizure-induced neurogenesis. Thus, these findings provide evidence that seizure-induced neurogenesis when adequately reduced in a clinically relevant time period has the potential to transiently suppress recurrent seizures, but additional mechanisms need to be targeted to permanently prevent epilepsy development.SIGNIFICANCE STATEMENT Consistent with morphological and electrophysiological studies suggesting aberrant adult-generated neurons contribute to epilepsy development, ablation of seizure-induced new neurons at the time of the initial insult reduces the frequency of recurrent seizures. In this study, we show that continuous targeting of post-insult new neurons in a therapeutically relevant time period reduces chronic seizures; however, this effect does not persist suggesting possible additional mechanisms.
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21
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Pauletti A, Terrone G, Shekh-Ahmad T, Salamone A, Ravizza T, Rizzi M, Pastore A, Pascente R, Liang LP, Villa BR, Balosso S, Abramov AY, van Vliet EA, Del Giudice E, Aronica E, Patel M, Walker MC, Vezzani A. Targeting oxidative stress improves disease outcomes in a rat model of acquired epilepsy. Brain 2019; 142:e39. [PMID: 31145451 PMCID: PMC6598637 DOI: 10.1093/brain/awz130] [Citation(s) in RCA: 132] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 03/17/2017] [Accepted: 03/26/2017] [Indexed: 01/07/2023] Open
Abstract
Epilepsy therapy is based on antiseizure drugs that treat the symptom, seizures, rather than the disease and are ineffective in up to 30% of patients. There are no treatments for modifying the disease-preventing seizure onset, reducing severity or improving prognosis. Among the potential molecular targets for attaining these unmet therapeutic needs, we focused on oxidative stress since it is a pathophysiological process commonly occurring in experimental epileptogenesis and observed in human epilepsy. Using a rat model of acquired epilepsy induced by electrical status epilepticus, we show that oxidative stress occurs in both neurons and astrocytes during epileptogenesis, as assessed by measuring biochemical and histological markers. This evidence was validated in the hippocampus of humans who died following status epilepticus. Oxidative stress was reduced in animals undergoing epileptogenesis by a transient treatment with N-acetylcysteine and sulforaphane, which act to increase glutathione levels through complementary mechanisms. These antioxidant drugs are already used in humans for other therapeutic indications. This drug combination transiently administered for 2 weeks during epileptogenesis inhibited oxidative stress more efficiently than either drug alone. The drug combination significantly delayed the onset of epilepsy, blocked disease progression between 2 and 5 months post-status epilepticus and drastically reduced the frequency of spontaneous seizures measured at 5 months without modifying the average seizure duration or the incidence of epilepsy in animals. Treatment also decreased hippocampal neuron loss and rescued cognitive deficits. Oxidative stress during epileptogenesis was associated with de novo brain and blood generation of high mobility group box 1 (HMGB1), a neuroinflammatory molecule implicated in seizure mechanisms. Drug-induced reduction of oxidative stress prevented HMGB1 generation, thus highlighting a potential novel mechanism contributing to therapeutic effects. Our data show that targeting oxidative stress with clinically used drugs for a limited time window starting early after injury significantly improves long-term disease outcomes. This intervention may be considered for patients exposed to potential epileptogenic insults.
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Affiliation(s)
- Alberto Pauletti
- 1 Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche
Mario Negri, Milan, Italy
| | - Gaetano Terrone
- 1 Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche
Mario Negri, Milan, Italy
| | - Tawfeeq Shekh-Ahmad
- 2 Department of Clinical and Experimental Epilepsy, University College
London, UK
| | - Alessia Salamone
- 1 Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche
Mario Negri, Milan, Italy
| | - Teresa Ravizza
- 1 Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche
Mario Negri, Milan, Italy
| | - Massimo Rizzi
- 1 Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche
Mario Negri, Milan, Italy
| | - Anna Pastore
- 3 Metabolomics and Proteomics Unit, ‘Bambino Gesù’ Children’s Hospital,
IRCCS, Rome, Italy
| | - Rosaria Pascente
- 1 Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche
Mario Negri, Milan, Italy
| | - Li-Ping Liang
- 4 Department of Pharmaceutical Sciences, University of Colorado Denver,
Aurora, Colorado, USA
| | - Bianca R Villa
- 1 Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche
Mario Negri, Milan, Italy
| | - Silvia Balosso
- 1 Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche
Mario Negri, Milan, Italy
| | - Andrey Y Abramov
- 2 Department of Clinical and Experimental Epilepsy, University College
London, UK
| | - Erwin A van Vliet
- 5 Department of (Neuro)Pathology, Academic Medical Center, University of
Amsterdam, The Netherlands
| | - Ennio Del Giudice
- 6 Department of Translational Medical Sciences, Section of Pediatrics,
Federico II University, Naples, Italy
| | - Eleonora Aronica
- 5 Department of (Neuro)Pathology, Academic Medical Center, University of
Amsterdam, The Netherlands
- 7 Stichting Epilepsie Instellingen Nederland, Amsterdam, The
Netherlands
| | - Manisha Patel
- 4 Department of Pharmaceutical Sciences, University of Colorado Denver,
Aurora, Colorado, USA
| | - Matthew C Walker
- 2 Department of Clinical and Experimental Epilepsy, University College
London, UK
| | - Annamaria Vezzani
- 1 Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche
Mario Negri, Milan, Italy
- Correpondence to: Annamaria Vezzani, PhD Department of Neuroscience
IRCCS-Istituto di Ricerche Farmacologiche Mario Negri Via G. La Masa 19, 20156 Milano,
Italy E-mail:
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22
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Seiffert I, van Dijk RM, Koska I, Di Liberto V, Möller C, Palme R, Hellweg R, Potschka H. Toward evidence-based severity assessment in rat models with repeated seizures: III. Electrical post-status epilepticus model. Epilepsia 2019; 60:1539-1551. [PMID: 31247135 DOI: 10.1111/epi.16095] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 06/03/2019] [Accepted: 06/03/2019] [Indexed: 12/30/2022]
Abstract
OBJECTIVE Ethical approval of experiments in chronic epilepsy models requires a careful balancing of the expected gain-in-knowledge with the level of distress. Thus recommendations for evidence-based severity assessment and classification are urgently needed for preclinical epilepsy research. METHODS Therefore, we have completed a comprehensive analysis of alterations in behavioral, biochemical, and physiological parameters in a rat electrical post-status epilepticus model. Selected parameters were repeatedly analyzed during different experimental phases to obtain information about the level of distress throughout the course of the model. RESULTS Behavioral patterns comprised an increase in activity along with a reduction in risk assessment behavior, active social interaction, saccharin preference as well as nonessential, but evolutionary-determined behavior such as nest building and burrowing. Among the biochemical parameters, fecal corticosterone metabolites proved to be increased in different phases of the experiment. In the early post-insult phase, this increase was reflected by elevated serum corticosterone concentrations. Telemetric recordings demonstrated increases in home cage activity and heart rate in selected experimental phases but argued against relevant changes in heart rate variability. Comparison between animals with tethered or telemetric recordings including a principal component analysis revealed differences between both groups. SIGNIFICANCE The present findings further confirm that burrowing behavior and saccharin preference might serve as valid parameters for severity assessment in chronic epilepsy models. Considering the course of alterations providing evidence for a more pronounced level of distress in the early phase following status epilepticus (SE), we suggest a classification of the electrical post-SE model as severe. This suggestion may serve as a guidance for laboratory-specific evaluations. Comparison between data from animals with tethered and telemetric recordings indicated an impact of the mode of recordings. However, further research is necessary to analyze the validity of telemetry as a putative refinement measure.
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Affiliation(s)
- Isabel Seiffert
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Roelof Maarten van Dijk
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Ines Koska
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Valentina Di Liberto
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig-Maximilians-University Munich, Munich, Germany.,Department of Experimental Biomedicine and Clinical Neurosciences, University of Palermo, Palermo, Italy
| | - Christina Möller
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Rupert Palme
- Department of Biomedical Sciences, University of Veterinary Medicine, Vienna, Austria
| | - Rainer Hellweg
- Department of Psychiatry and Psychotherapy, Charité, Berlin, Germany
| | - Heidrun Potschka
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig-Maximilians-University Munich, Munich, Germany
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23
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In vivo measurement of brain network connectivity reflects progression and intrinsic disease severity in a model of temporal lobe epilepsy. Neurobiol Dis 2019; 127:45-52. [PMID: 30798008 DOI: 10.1016/j.nbd.2019.02.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2018] [Revised: 01/30/2019] [Accepted: 02/20/2019] [Indexed: 12/23/2022] Open
Abstract
Different types of brain injury, such as status epilepticus (SE), trauma, or stroke may initiate the process of epileptogenesis and lead to the development of temporal lobe epilepsy. Epileptogenesis is characterized by an initial latent period during which impaired network communication and synaptic circuit alterations are occurring. Ultimately, these modifications result in the development of spontaneous recurrent seizures (SRS). Current knowledge on the functional connectivity network changes during epileptogenesis and how network alterations relate to seizure is very limited. To investigate these underlying network connectivity modifications, we imaged epileptic and control rats by means of resting-state functional MRI (rsfMRI) during epileptogenesis. A cohort of animals was video-electroencephalography (video-EEG) monitored continuously over 12 weeks to determine disease severity during the course of disease, with the first SRS appearing around 2 weeks post-SE for most of the animals. Epileptic animals displayed a significant wide-spread hyposynchrony at 2 weeks post-SE, followed by a significant increase in network synchronicity from 2 to 4 weeks post-SE. Interestingly, subjects with a delayed epilepsy onset demonstrated significantly lower synchronicity compared to controls and the epileptic group at 4 weeks post-SE. Finally, network connectivity at 4 weeks post-SE was found to correlate with seizure onset (r = 0.858, p < .0001) and disease severity measured over 12 weeks (e.g. cingulate cortex: r = 0.863, p = .002), suggesting a possible network strengthening upon seizure reoccurrence. Our findings indicate that epileptogenesis is characterized by an initial hyposynchrony of brain networks and the disease-associated progression reflects disease severity.
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24
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Cavarsan CF, Malheiros J, Hamani C, Najm I, Covolan L. Is Mossy Fiber Sprouting a Potential Therapeutic Target for Epilepsy? Front Neurol 2018; 9:1023. [PMID: 30555406 PMCID: PMC6284045 DOI: 10.3389/fneur.2018.01023] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 11/13/2018] [Indexed: 11/13/2022] Open
Abstract
Mesial temporal lobe epilepsy (MTLE) caused by hippocampal sclerosis is one of the most frequent focal epilepsies in adults. It is characterized by focal seizures that begin in the hippocampus, sometimes spread to the insulo-perisylvian regions and may progress to secondary generalized seizures. Morphological alterations in hippocampal sclerosis are well defined. Among them, hippocampal sclerosis is characterized by prominent cell loss in the hilus and CA1, and abnormal mossy fiber sprouting (granular cell axons) into the dentate gyrus inner molecular layer. In this review, we highlight the role of mossy fiber sprouting in seizure generation and hippocampal excitability and discuss the response of alternative treatment strategies in terms of MFS and spontaneous recurrent seizures in models of TLE (temporal lobe epilepsy).
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Affiliation(s)
- Clarissa F Cavarsan
- Department of Physiology, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Jackeline Malheiros
- Department of Physiology, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Clement Hamani
- Department of Physiology, Universidade Federal de São Paulo, São Paulo, Brazil.,Harquail Centre for Neuromodulation, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, ON, Canada
| | - Imad Najm
- Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, OH, United States
| | - Luciene Covolan
- Department of Physiology, Universidade Federal de São Paulo, São Paulo, Brazil.,Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, OH, United States
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25
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Lam PM, González MI. Calpain activation and neuronal death during early epileptogenesis. Neurobiol Dis 2018; 124:141-151. [PMID: 30423475 DOI: 10.1016/j.nbd.2018.11.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2018] [Revised: 11/02/2018] [Accepted: 11/09/2018] [Indexed: 12/21/2022] Open
Abstract
Epilepsy is a brain disorder characterized by a predisposition to suffer epileptic seizures. Acquired epilepsy might be the result of brain insults like head trauma, stroke, brain infection, or status epilepticus (SE) when one of these triggering injuries starts a transformative process known as epileptogenesis. There is some data to suggest that, during epileptogenesis, seizures themselves damage the brain but there is no conclusive evidence to demonstrate that spontaneous recurrent seizures themselves injure the brain. Our recent evidence indicates that calpain overactivation might be relevant for epileptogenesis. Here, we investigated if spontaneous recurrent seizures that occur during an early period of epileptogenesis show any correlation with the levels of calpain activation and/or expression. In addition, we also investigated a possible association between the occurrence of spontaneous seizures and increased levels of cell death, gliosis and inflammation (typical markers associated with epileptogenesis). We found that the number of spontaneous seizures detected prior to sample collection was correlated with altered calpain activity and expression. Moreover, the levels of hippocampal neurodegeneration were also correlated with seizure occurrence. Our findings suggest that, at least during early epileptogenesis, there is a correlation between seizure occurrence, calpain activity and neurodegeneration. Thus, this study opens the possibility that aberrant calpain reactivation by spontaneous seizures might contribute to the manifestation of future spontaneous seizures.
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Affiliation(s)
- Philip M Lam
- Department of Pediatrics, Division of Neurology and Translational Epilepsy Research Program, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Marco I González
- Department of Pediatrics, Division of Neurology and Translational Epilepsy Research Program, University of Colorado School of Medicine, Aurora, CO 80045, USA.
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26
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Rutland JW, Feldman RE, Delman BN, Panov F, Fields MC, Marcuse LV, Hof PR, Lin HM, Balchandani P. Subfield-specific tractography of the hippocampus in epilepsy patients at 7 Tesla. Seizure 2018; 62:3-10. [PMID: 30245458 PMCID: PMC6221989 DOI: 10.1016/j.seizure.2018.09.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 08/29/2018] [Accepted: 09/12/2018] [Indexed: 10/28/2022] Open
Abstract
PURPOSE MRI-negative epilepsy patients could benefit from advanced imaging techniques such as high-resolution diffusion magnetic resonance imaging (dMRI). Our aim was to perform hippocampal subfield-specific tractography and quantify connectivity of the subfields in MRI-negative patients. Abnormal connectivity of the hippocampal subfields may help inform seizure focus hypothesis and provide information to guide surgical intervention. METHODS Hippocampal structural imaging and dMRI was acquired in 25 drug resistant MRI-negative patients and 25 healthy volunteers. The hippocampi of each subject was segmented on high-resolution structural images and dMRI-based probabilistic tractography was performed in each subfield. The degrees of connectivity and fiber densities of the hippocampal subfields were quantified and compared between epilepsy patients and healthy volunteers. RESULTS We were able to perform subfield-specific hippocampal tractography in each subject that participated in this study. These methods identified some hippocampal subfields that are abnormally connected in MRI-negative patients. In particular patients suspected of left temporal seizure focus exhibited increased connectivity of certain ipsilateral subfields, especially the subiculum, presubiculum, and parasubiculum, and reduced connectivity of some contralateral subfields, such as CA1 and subiculum. CONCLUSIONS Our data suggest that the hippocampal subfields are connected in distinct ways in different types of epilepsy. These results may provide important information that could help inform seizure focus hypothesis and in the surgical treatment of MRI-negative patients. These observations suggest that high-resolution dMRI-based tractography of the hippocampal subfields can detect subtle abnormalities in otherwise normal-appearing MRI-negative patients.
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Affiliation(s)
- John W Rutland
- Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States; Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, NY, United States.
| | - Rebecca E Feldman
- Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States; Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Bradley N Delman
- Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Fedor Panov
- Department of Neurosurgery, Mount Sinai Hospital, New York, NY, United States
| | - Madeline C Fields
- Department of Neurology, Mount Sinai Hospital, New York, NY, United States
| | - Lara V Marcuse
- Department of Neurology, Mount Sinai Hospital, New York, NY, United States
| | - Patrick R Hof
- Department of Neuroscience, Mount Sinai Hospital, New York, NY, United States
| | - Hung-Mo Lin
- Department of Population Health Science and Policy, Mount Sinai Hospital, New York, NY, United States
| | - Priti Balchandani
- Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States; Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, NY, United States
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27
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Korotkov A, Broekaart DWM, van Scheppingen J, Anink JJ, Baayen JC, Idema S, Gorter JA, Aronica E, van Vliet EA. Increased expression of matrix metalloproteinase 3 can be attenuated by inhibition of microRNA-155 in cultured human astrocytes. J Neuroinflammation 2018; 15:211. [PMID: 30031401 PMCID: PMC6054845 DOI: 10.1186/s12974-018-1245-y] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2018] [Accepted: 07/02/2018] [Indexed: 12/21/2022] Open
Abstract
Background Temporal lobe epilepsy (TLE) is a chronic neurological disease, in which about 30% of patients cannot be treated adequately with anti-epileptic drugs. Brain inflammation and remodeling of the extracellular matrix (ECM) seem to play a major role in TLE. Matrix metalloproteinases (MMPs) are proteolytic enzymes largely responsible for the remodeling of the ECM. The inhibition of MMPs has been suggested as a novel therapy for epilepsy; however, available MMP inhibitors lack specificity and cause serious side effects. We studied whether MMPs could be modulated via microRNAs (miRNAs). Several miRNAs mediate inflammatory responses in the brain, which are known to control MMP expression. The aim of this study was to investigate whether an increased expression of MMPs after interleukin-1β (IL-1β) stimulation can be attenuated by inhibition of the inflammation-associated miR-155. Methods We investigated the expression of MMP2, MMP3, MMP9, and MMP14 in cultured human fetal astrocytes after stimulation with the pro-inflammatory cytokine IL-1β. The cells were transfected with miR-155 antagomiR, and the effect on MMP3 expression was investigated using real-time quantitative PCR and Western blotting. Furthermore, we characterized MMP3 and miR-155 expression in brain tissue of TLE patients with hippocampal sclerosis (TLE-HS) and during epileptogenesis in a rat TLE model. Results Inhibition of miR-155 by the antagomiR attenuated MMP3 overexpression after IL-1β stimulation in astrocytes. Increased expression of MMP3 and miR-155 was also evident in the hippocampus of TLE-HS patients and throughout epileptogenesis in the rat TLE model. Conclusions Our experiments showed that MMP3 is dynamically regulated by seizures as shown by increased expression in TLE tissue and during different phases of epileptogenesis in the rat TLE model. MMP3 can be induced by the pro-inflammatory cytokine IL-1β and is regulated by miR-155, suggesting a possible strategy to prevent epilepsy via reduction of inflammation. Electronic supplementary material The online version of this article (10.1186/s12974-018-1245-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Anatoly Korotkov
- Department of (Neuro) Pathology, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
| | - Diede W M Broekaart
- Department of (Neuro) Pathology, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
| | - Jackelien van Scheppingen
- Department of (Neuro) Pathology, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
| | - Jasper J Anink
- Department of (Neuro) Pathology, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
| | - Johannes C Baayen
- Department of Neurosurgery, Amsterdam UMC, Vrije Universiteit Amsterdam, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands
| | - Sander Idema
- Department of Neurosurgery, Amsterdam UMC, Vrije Universiteit Amsterdam, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands
| | - Jan A Gorter
- Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands
| | - Eleonora Aronica
- Department of (Neuro) Pathology, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands.,Stichting Epilepsie Instellingen Nederland (SEIN), Heemstede, The Netherlands
| | - Erwin A van Vliet
- Department of (Neuro) Pathology, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands. .,Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands.
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28
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Khan AA, Shekh-Ahmad T, Khalil A, Walker MC, Ali AB. Cannabidiol exerts antiepileptic effects by restoring hippocampal interneuron functions in a temporal lobe epilepsy model. Br J Pharmacol 2018; 175:2097-2115. [PMID: 29574880 PMCID: PMC5979781 DOI: 10.1111/bph.14202] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 12/13/2017] [Accepted: 02/27/2018] [Indexed: 12/29/2022] Open
Abstract
Background and Purpose A non‐psychoactive phytocannabinoid, cannabidiol (CBD), shows promising results as an effective potential antiepileptic drug in some forms of refractory epilepsy. To elucidate the mechanisms by which CBD exerts its anti‐seizure effects, we investigated its effects at synaptic connections and on the intrinsic membrane properties of hippocampal CA1 pyramidal cells and two major inhibitory interneurons: fast spiking, parvalbumin (PV)‐expressing and adapting, cholecystokinin (CCK)‐expressing interneurons. We also investigated whether in vivo treatment with CBD altered the fate of CCK and PV interneurons using immunohistochemistry. Experimental Approach Electrophysiological intracellular whole‐cell recordings combined with neuroanatomy were performed in acute brain slices of rat temporal lobe epilepsy in in vivo (induced by kainic acid) and in vitro (induced by Mg2+‐free solution) epileptic seizure models. For immunohistochemistry experiments, CBD was administered in vivo (100 mg·kg−1) at zero time and 90 min post status epilepticus, induced with kainic acid. Key Results Bath application of CBD (10 μM) dampened excitability at unitary synapses between pyramidal cells but enhanced inhibitory synaptic potentials elicited by fast spiking and adapting interneurons at postsynaptic pyramidal cells. Furthermore, CBD restored impaired membrane excitability of PV, CCK and pyramidal cells in a cell type‐specific manner. These neuroprotective effects of CBD were corroborated by immunohistochemistry experiments that revealed a significant reduction in atrophy and death of PV‐ and CCK‐expressing interneurons after CBD treatment. Conclusions and Implications Our data suggest that CBD restores excitability and morphological impairments in epileptic models to pre‐epilepsy control levels through multiple mechanisms to reinstate normal network function.
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Affiliation(s)
| | | | | | | | - Afia B Ali
- UCL School of Pharmacy, London, WC1N 1AX, UK
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29
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Nirwan N, Vyas P, Vohora D. Animal models of status epilepticus and temporal lobe epilepsy: a narrative review. Rev Neurosci 2018; 29:757-770. [DOI: 10.1515/revneuro-2017-0086] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 01/26/2018] [Indexed: 11/15/2022]
Abstract
Abstract
Temporal lobe epilepsy (TLE) is the chronic and pharmacoresistant form of epilepsy observed in humans. The current literature is insufficient in explicating the comprehensive mechanisms underlying its pathogenesis and advancement. Consequently, the development of a suitable animal model mimicking the clinical characteristics is required. Further, the relevance of status epilepticus (SE) to animal models is dubious. SE occurs rarely in people; most epilepsy patients never experience it. The present review summarizes the established animal models of SE and TLE, along with a brief discussion of the animal models that have the distinctiveness and carries the possibility to be developed as effective models for TLE. The review not only covers the basic requirements, mechanisms, and methods of induction of each model but also focuses upon their major limitations and possible modifications for their future use. A detailed discussion on chemical, electrical, and hypoxic/ischemic models as well as a brief explanation on the genetic models, most of which are characterized by development of SE followed by neurodegeneration, is presented.
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Affiliation(s)
- Nikita Nirwan
- Neurobehavioral Pharmacology Laboratory , Department of Pharmacology , School of Pharmaceutical Education and Research, Jamia Hamdard , New Delhi 110062 , India
| | - Preeti Vyas
- Neurobehavioral Pharmacology Laboratory , Department of Pharmacology , School of Pharmaceutical Education and Research, Jamia Hamdard , New Delhi 110062 , India
| | - Divya Vohora
- Neurobehavioral Pharmacology Laboratory , Department of Pharmacology , School of Pharmaceutical Education and Research, Jamia Hamdard , New Delhi 110062 , India
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30
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Abstract
Epilepsy, characterized by spontaneous recurrent seizures (SRS), is a serious and common neurological disorder afflicting an estimated 1% of the population worldwide. Animal experiments, especially those utilizing small laboratory rodents, remain essential to understanding the fundamental mechanisms underlying epilepsy and to prevent, diagnose, and treat this disease. While much attention has been focused on epileptogenesis in animal models of epilepsy, there is little discussion on SRS, the hallmark of epilepsy. This is in part due to the technical difficulties of rigorous SRS detection. In this review, we comprehensively summarize both genetic and acquired models of SRS and discuss the methodology used to monitor and detect SRS in mice and rats.
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Affiliation(s)
- Bin Gu
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC 27599, USA.
| | - Katherine A Dalton
- Psychology & Neuroscience Program, University of North Carolina, Chapel Hill, NC 27599, USA
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31
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32
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Neumann AR, Raedt R, Steenland HW, Sprengers M, Bzymek K, Navratilova Z, Mesina L, Xie J, Lapointe V, Kloosterman F, Vonck K, Boon PAJM, Soltesz I, McNaughton BL, Luczak A. Involvement of fast-spiking cells in ictal sequences during spontaneous seizures in rats with chronic temporal lobe epilepsy. Brain 2017; 140:2355-2369. [PMID: 29050390 PMCID: PMC6248724 DOI: 10.1093/brain/awx179] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 05/25/2017] [Accepted: 06/08/2017] [Indexed: 11/14/2022] Open
Abstract
See Lenck-Santini (doi:10.1093/awx205) for a scientific commentary on this article. Epileptic seizures represent altered neuronal network dynamics, but the temporal evolution and cellular substrates of the neuronal activity patterns associated with spontaneous seizures are not fully understood. We used simultaneous recordings from multiple neurons in the hippocampus and neocortex of rats with chronic temporal lobe epilepsy to demonstrate that subsets of cells discharge in a highly stereotypical sequential pattern during ictal events, and that these stereotypical patterns were reproducible across consecutive seizures. In contrast to the canonical view that principal cell discharges dominate ictal events, the ictal sequences were predominantly composed of fast-spiking, putative inhibitory neurons, which displayed unusually strong coupling to local field potential even before seizures. The temporal evolution of activity was characterized by unique dynamics where the most correlated neuronal pairs before seizure onset displayed the largest increases in correlation strength during the seizures. These results demonstrate the selective involvement of fast spiking interneurons in structured temporal sequences during spontaneous ictal events in hippocampal and neocortical circuits in experimental models of chronic temporal lobe epilepsy.
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Affiliation(s)
- Adam R Neumann
- Department of Neuroscience, Canadian Centre for Behavioural
Neuroscience, University of Lethbridge, 4401 University Dr W, Lethbridge, AB, T1K 3M4,
Canada
| | - Robrecht Raedt
- Department of Neurology, Ghent University, Gent, Belgium
| | - Hendrik W Steenland
- Department of Neuroscience, Canadian Centre for Behavioural
Neuroscience, University of Lethbridge, 4401 University Dr W, Lethbridge, AB, T1K 3M4,
Canada
| | | | - Katarzyna Bzymek
- Department of Neuroscience, Canadian Centre for Behavioural
Neuroscience, University of Lethbridge, 4401 University Dr W, Lethbridge, AB, T1K 3M4,
Canada
| | - Zaneta Navratilova
- Department of Neuroscience, Canadian Centre for Behavioural
Neuroscience, University of Lethbridge, 4401 University Dr W, Lethbridge, AB, T1K 3M4,
Canada
- Neuro-Electronics Research Flanders, Leuven, Belgium
| | - Lilia Mesina
- Department of Neuroscience, Canadian Centre for Behavioural
Neuroscience, University of Lethbridge, 4401 University Dr W, Lethbridge, AB, T1K 3M4,
Canada
| | - Jeanne Xie
- Department of Neuroscience, Canadian Centre for Behavioural
Neuroscience, University of Lethbridge, 4401 University Dr W, Lethbridge, AB, T1K 3M4,
Canada
| | - Valerie Lapointe
- Department of Neuroscience, Canadian Centre for Behavioural
Neuroscience, University of Lethbridge, 4401 University Dr W, Lethbridge, AB, T1K 3M4,
Canada
| | - Fabian Kloosterman
- Neuro-Electronics Research Flanders, Leuven, Belgium
- VIB, Leuven, Belgium
- Brain and Cognition Research unit, KU Leuven, Leuven, Belgium
| | - Kristl Vonck
- Department of Neurology, Ghent University, Gent, Belgium
| | | | - Ivan Soltesz
- Department of Neurosurgery, and Stanford Neurosciences Institute,
Stanford University, Stanford, CA, USA
| | - Bruce L McNaughton
- Department of Neuroscience, Canadian Centre for Behavioural
Neuroscience, University of Lethbridge, 4401 University Dr W, Lethbridge, AB, T1K 3M4,
Canada
- Department of Neurobiology and Behavior, University of California at
Irvine, Center for the Neurobiology of Learning and Memory, Irvine, CA, USA
| | - Artur Luczak
- Department of Neuroscience, Canadian Centre for Behavioural
Neuroscience, University of Lethbridge, 4401 University Dr W, Lethbridge, AB, T1K 3M4,
Canada
- Department of Neurosurgery, and Stanford Neurosciences Institute,
Stanford University, Stanford, CA, USA
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33
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Pauletti A, Terrone G, Shekh-Ahmad T, Salamone A, Ravizza T, Rizzi M, Pastore A, Pascente R, Liang LP, Villa BR, Balosso S, Abramov AY, van Vliet EA, Del Giudice E, Aronica E, Antoine DJ, Patel M, Walker MC, Vezzani A. Targeting oxidative stress improves disease outcomes in a rat model of acquired epilepsy. Brain 2017; 140:1885-1899. [PMID: 28575153 DOI: 10.1093/brain/awx117] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 03/26/2017] [Indexed: 12/31/2022] Open
Abstract
Epilepsy therapy is based on antiseizure drugs that treat the symptom, seizures, rather than the disease and are ineffective in up to 30% of patients. There are no treatments for modifying the disease-preventing seizure onset, reducing severity or improving prognosis. Among the potential molecular targets for attaining these unmet therapeutic needs, we focused on oxidative stress since it is a pathophysiological process commonly occurring in experimental epileptogenesis and observed in human epilepsy. Using a rat model of acquired epilepsy induced by electrical status epilepticus, we show that oxidative stress occurs in both neurons and astrocytes during epileptogenesis, as assessed by measuring biochemical and histological markers. This evidence was validated in the hippocampus of humans who died following status epilepticus. Oxidative stress was reduced in animals undergoing epileptogenesis by a transient treatment with N-acetylcysteine and sulforaphane, which act to increase glutathione levels through complementary mechanisms. These antioxidant drugs are already used in humans for other therapeutic indications. This drug combination transiently administered for 2 weeks during epileptogenesis inhibited oxidative stress more efficiently than either drug alone. The drug combination significantly delayed the onset of epilepsy, blocked disease progression between 2 and 5 months post-status epilepticus and drastically reduced the frequency of spontaneous seizures measured at 5 months without modifying the average seizure duration or the incidence of epilepsy in animals. Treatment also decreased hippocampal neuron loss and rescued cognitive deficits. Oxidative stress during epileptogenesis was associated with de novo brain and blood generation of disulfide high mobility group box 1 (HMGB1), a neuroinflammatory molecule implicated in seizure mechanisms. Drug-induced reduction of oxidative stress prevented disulfide HMGB1 generation, thus highlighting a potential novel mechanism contributing to therapeutic effects. Our data show that targeting oxidative stress with clinically used drugs for a limited time window starting early after injury significantly improves long-term disease outcomes. This intervention may be considered for patients exposed to potential epileptogenic insults.
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Affiliation(s)
- Alberto Pauletti
- Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy
| | - Gaetano Terrone
- Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy
| | - Tawfeeq Shekh-Ahmad
- Department of Clinical and Experimental Epilepsy, University College London, UK
| | - Alessia Salamone
- Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy
| | - Teresa Ravizza
- Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy
| | - Massimo Rizzi
- Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy
| | - Anna Pastore
- Metabolomics and Proteomics Unit, 'Bambino Gesù' Children's Hospital, IRCCS, Rome, Italy
| | - Rosaria Pascente
- Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy
| | - Li-Ping Liang
- Department of Pharmaceutical Sciences, University of Colorado Denver, Aurora, Colorado, USA
| | - Bianca R Villa
- Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy
| | - Silvia Balosso
- Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy
| | - Andrey Y Abramov
- Department of Clinical and Experimental Epilepsy, University College London, UK
| | - Erwin A van Vliet
- Department of (Neuro)Pathology, Academic Medical Center, University of Amsterdam, The Netherlands
| | - Ennio Del Giudice
- Department of Translational Medical Sciences, Section of Pediatrics, Federico II University, Naples, Italy
| | - Eleonora Aronica
- Department of (Neuro)Pathology, Academic Medical Center, University of Amsterdam, The Netherlands.,Stichting Epilepsie Instellingen Nederland, Amsterdam, The Netherlands
| | - Daniel J Antoine
- MRC Centre for Drug Safety Science, Department of Molecular and Clinical Pharmacology, University of Liverpool, Liverpool, UK
| | - Manisha Patel
- Department of Pharmaceutical Sciences, University of Colorado Denver, Aurora, Colorado, USA
| | - Matthew C Walker
- Department of Clinical and Experimental Epilepsy, University College London, UK
| | - Annamaria Vezzani
- Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy
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34
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Buckmaster PS, Abrams E, Wen X. Seizure frequency correlates with loss of dentate gyrus GABAergic neurons in a mouse model of temporal lobe epilepsy. J Comp Neurol 2017; 525:2592-2610. [PMID: 28425097 PMCID: PMC5963263 DOI: 10.1002/cne.24226] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 04/11/2017] [Accepted: 04/12/2017] [Indexed: 01/19/2023]
Abstract
Epilepsy occurs in one of 26 people. Temporal lobe epilepsy is common and can be difficult to treat effectively. It can develop after brain injuries that damage the hippocampus. Multiple pathophysiological mechanisms involving the hippocampal dentate gyrus have been proposed. This study evaluated a mouse model of temporal lobe epilepsy to test which pathological changes in the dentate gyrus correlate with seizure frequency and help prioritize potential mechanisms for further study. FVB mice (n = 127) that had experienced status epilepticus after systemic treatment with pilocarpine 31-61 days earlier were video-monitored for spontaneous, convulsive seizures 9 hr/day every day for 24-36 days. Over 4,060 seizures were observed. Seizure frequency ranged from an average of one every 3.6 days to one every 2.1 hr. Hippocampal sections were processed for Nissl stain, Prox1-immunocytochemistry, GluR2-immunocytochemistry, Timm stain, glial fibrillary acidic protein-immunocytochemistry, glutamic acid decarboxylase in situ hybridization, and parvalbumin-immunocytochemistry. Stereological methods were used to measure hilar ectopic granule cells, mossy cells, mossy fiber sprouting, astrogliosis, and GABAergic interneurons. Seizure frequency was not significantly correlated with the generation of hilar ectopic granule cells, the number of mossy cells, the extent of mossy fiber sprouting, the extent of astrogliosis, or the number of GABAergic interneurons in the molecular layer or hilus. Seizure frequency significantly correlated with the loss of GABAergic interneurons in or adjacent to the granule cell layer, but not with the loss of parvalbumin-positive interneurons. These findings prioritize the loss of granule cell layer interneurons for further testing as a potential cause of temporal lobe epilepsy.
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Affiliation(s)
- Paul S. Buckmaster
- Department of Comparative Medicine, Stanford University, Stanford, California
- Department of Neurology & Neurological Sciences, Stanford University, Stanford, California
| | - Emily Abrams
- Department of Comparative Medicine, Stanford University, Stanford, California
| | - Xiling Wen
- Department of Comparative Medicine, Stanford University, Stanford, California
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35
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Dhamne SC, Silverman JL, Super CE, Lammers SHT, Hameed MQ, Modi ME, Copping NA, Pride MC, Smith DG, Rotenberg A, Crawley JN, Sahin M. Replicable in vivo physiological and behavioral phenotypes of the Shank3B null mutant mouse model of autism. Mol Autism 2017. [PMID: 28638591 PMCID: PMC5472997 DOI: 10.1186/s13229-017-0142-z] [Citation(s) in RCA: 107] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Autism spectrum disorder (ASD) is a clinically and biologically heterogeneous condition characterized by social, repetitive, and sensory behavioral abnormalities. No treatments are approved for the core diagnostic symptoms of ASD. To enable the earliest stages of therapeutic discovery and development for ASD, robust and reproducible behavioral phenotypes and biological markers are essential to establish in preclinical animal models. The goal of this study was to identify electroencephalographic (EEG) and behavioral phenotypes that are replicable between independent cohorts in a mouse model of ASD. The larger goal of our strategy is to empower the preclinical biomedical ASD research field by generating robust and reproducible behavioral and physiological phenotypes in animal models of ASD, for the characterization of mechanistic underpinnings of ASD-relevant phenotypes, and to ensure reliability for the discovery of novel therapeutics. Genetic disruption of the SHANK3 gene, a scaffolding protein involved in the stability of the postsynaptic density in excitatory synapses, is thought to be responsible for a relatively large number of cases of ASD. Therefore, we have thoroughly characterized the robustness of ASD-relevant behavioral phenotypes in two cohorts, and for the first time quantified translational EEG activity in Shank3B null mutant mice. METHODS In vivo physiology and behavioral assays were conducted in two independently bred and tested full cohorts of Shank3B null mutant (Shank3B KO) and wildtype littermate control (WT) mice. EEG was recorded via wireless implanted telemeters for 7 days of baseline followed by 20 min of recording following pentylenetetrazol (PTZ) challenge. Behaviors relevant to the diagnostic and associated symptoms of ASD were tested on a battery of established behavioral tests. Assays were designed to reproduce and expand on the original behavioral characterization of Shank3B KO mice. Two or more corroborative tests were conducted within each behavioral domain, including social, repetitive, cognitive, anxiety-related, sensory, and motor categories of assays. RESULTS Relative to WT mice, Shank3B KO mice displayed a dramatic resistance to PTZ seizure induction and an enhancement of gamma band oscillatory EEG activity indicative of enhanced inhibitory tone. These findings replicated in two separate cohorts. Behaviorally, Shank3B KO mice exhibited repetitive grooming, deficits in aspects of reciprocal social interactions and vocalizations, and reduced open field activity, as well as variable deficits in sensory responses, anxiety-related behaviors, learning and memory. CONCLUSIONS Robust animal models and quantitative, replicable biomarkers of neural dysfunction are needed to decrease risk and enable successful drug discovery and development for ASD and other neurodevelopmental disorders. Complementary to the replicated behavioral phenotypes of the Shank3B mutant mouse is the new identification of a robust, translational in vivo neurophysiological phenotype. Our findings provide strong evidence for robustness and replicability of key translational phenotypes in Shank3B mutant mice and support the usefulness of this mouse model of ASD for therapeutic discovery.
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Affiliation(s)
- Sameer C Dhamne
- F.M. Kirby Neurobiology Center, Translational Neuroscience Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115 USA
| | - Jill L Silverman
- MIND Institute, Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine, Sacramento, CA 95821 USA
| | - Chloe E Super
- F.M. Kirby Neurobiology Center, Translational Neuroscience Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115 USA
| | - Stephen H T Lammers
- F.M. Kirby Neurobiology Center, Translational Neuroscience Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115 USA
| | - Mustafa Q Hameed
- F.M. Kirby Neurobiology Center, Translational Neuroscience Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115 USA
| | - Meera E Modi
- F.M. Kirby Neurobiology Center, Translational Neuroscience Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115 USA
| | - Nycole A Copping
- MIND Institute, Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine, Sacramento, CA 95821 USA
| | - Michael C Pride
- MIND Institute, Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine, Sacramento, CA 95821 USA
| | - Daniel G Smith
- Autism Speaks, Inc., Boston, MA USA.,Present address: BlackThorn Therapeutics, Inc., Cambridge, MA USA
| | - Alexander Rotenberg
- F.M. Kirby Neurobiology Center, Translational Neuroscience Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115 USA
| | - Jacqueline N Crawley
- MIND Institute, Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine, Sacramento, CA 95821 USA
| | - Mustafa Sahin
- F.M. Kirby Neurobiology Center, Translational Neuroscience Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115 USA
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36
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Soares JI, Valente MC, Andrade PA, Maia GH, Lukoyanov NV. Reorganization of the septohippocampal cholinergic fiber system in experimental epilepsy. J Comp Neurol 2017; 525:2690-2705. [PMID: 28472854 DOI: 10.1002/cne.24235] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Revised: 04/11/2017] [Accepted: 04/24/2017] [Indexed: 12/28/2022]
Abstract
The septohippocampal cholinergic neurotransmission has long been implicated in seizures, but little is known about the structural features of this projection system in epileptic brain. We evaluated the effects of experimental epilepsy on the areal density of cholinergic terminals (fiber varicosities) in the dentate gyrus. For this purpose, we used two distinct post-status epilepticus rat models, in which epilepsy was induced with injections of either kainic acid or pilocarpine. To visualize the cholinergic fibers, we used brain sections immunostained for the vesicular acetylcholine transporter. It was found that the density of cholinergic fiber varicosities was higher in epileptic rats versus control rats in the inner and outer zones of the dentate molecular layer, but it was reduced in the dentate hilus. We further evaluated the effects of kainate treatment on the total number, density, and soma volume of septal cholinergic cells, which were visualized in brain sections stained for either vesicular acetylcholine transporter or choline acetyltransferase (ChAT). Both the number of septal cells with cholinergic phenotype and their density were increased in epileptic rats when compared to control rats. The septal cells stained for vesicular acetylcholine transporter, but not for ChAT, have enlarged perikarya in epileptic rats. These results revealed previously unknown details of structural reorganization of the septohippocampal cholinergic system in experimental epilepsy, involving fiber sprouting into the dentate molecular layer and a parallel fiber retraction from the dentate hilus. We hypothesize that epilepsy-related neuroplasticity of septohippocampal cholinergic neurons is capable of increasing neuronal excitability of the dentate gyrus.
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Affiliation(s)
- Joana I Soares
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Portugal.,Neuronal Networks Group, Instituto de Biologia Molecular e Celular da Universidade do Porto, Porto, Portugal.,Departamento de Biologia Experimental, Faculdade de Medicina da Universidade do Porto, Porto, Portugal.,Programa Doutoral em Neurociências, Universidade do Porto, Porto, Portugal
| | - Maria C Valente
- Departamento de Biologia Experimental, Faculdade de Medicina da Universidade do Porto, Porto, Portugal
| | - Pedro A Andrade
- Programa Doutoral em Neurociências, Universidade do Porto, Porto, Portugal.,Department of Neurobiology, A.I. Virtanen Institute, University of Eastern Finland, Kuopio, Finland
| | - Gisela H Maia
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Portugal.,Neuronal Networks Group, Instituto de Biologia Molecular e Celular da Universidade do Porto, Porto, Portugal.,Departamento de Biologia Experimental, Faculdade de Medicina da Universidade do Porto, Porto, Portugal.,Programa Doutoral em Neurociências, Universidade do Porto, Porto, Portugal
| | - Nikolai V Lukoyanov
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Portugal.,Neuronal Networks Group, Instituto de Biologia Molecular e Celular da Universidade do Porto, Porto, Portugal.,Departamento de Anatomia, Faculdade de Medicina da Universidade do Porto, Porto, Portugal
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37
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Walker LE, Frigerio F, Ravizza T, Ricci E, Tse K, Jenkins RE, Sills GJ, Jorgensen A, Porcu L, Thippeswamy T, Alapirtti T, Peltola J, Brodie MJ, Park BK, Marson AG, Antoine DJ, Vezzani A, Pirmohamed M. Molecular isoforms of high-mobility group box 1 are mechanistic biomarkers for epilepsy. J Clin Invest 2017; 127:2118-2132. [PMID: 28504645 PMCID: PMC5451237 DOI: 10.1172/jci92001] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 03/16/2017] [Indexed: 01/09/2023] Open
Abstract
Approximately 30% of epilepsy patients do not respond to antiepileptic drugs, representing an unmet medical need. There is evidence that neuroinflammation plays a pathogenic role in drug-resistant epilepsy. The high-mobility group box 1 (HMGB1)/TLR4 axis is a key initiator of neuroinflammation following epileptogenic injuries, and its activation contributes to seizure generation in animal models. However, further work is required to understand the role of HMGB1 and its isoforms in epileptogenesis and drug resistance. Using a combination of animal models and sera from clinically well-characterized patients, we have demonstrated that there are dynamic changes in HMGB1 isoforms in the brain and blood of animals undergoing epileptogenesis. The pathologic disulfide HMGB1 isoform progressively increased in blood before epilepsy onset and prospectively identified animals that developed the disease. Consistent with animal data, we observed early expression of disulfide HMGB1 in patients with newly diagnosed epilepsy, and its persistence was associated with subsequent seizures. In contrast with patients with well-controlled epilepsy, patients with chronic, drug-refractory epilepsy persistently expressed the acetylated, disulfide HMGB1 isoforms. Moreover, treatment of animals with antiinflammatory drugs during epileptogenesis prevented both disease progression and blood increase in HMGB1 isoforms. Our data suggest that HMGB1 isoforms are mechanistic biomarkers for epileptogenesis and drug-resistant epilepsy in humans, necessitating evaluation in larger-scale prospective studies.
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Affiliation(s)
- Lauren Elizabeth Walker
- Department of Molecular and Clinical Pharmacology, University of Liverpool, Liverpool, United Kingdom
| | | | | | - Emanuele Ricci
- Department of Molecular and Clinical Pharmacology, University of Liverpool, Liverpool, United Kingdom
| | - Karen Tse
- Department of Molecular and Clinical Pharmacology, University of Liverpool, Liverpool, United Kingdom
| | - Rosalind E Jenkins
- Department of Molecular and Clinical Pharmacology, University of Liverpool, Liverpool, United Kingdom
| | - Graeme John Sills
- Department of Molecular and Clinical Pharmacology, University of Liverpool, Liverpool, United Kingdom
| | - Andrea Jorgensen
- Department of Molecular and Clinical Pharmacology, University of Liverpool, Liverpool, United Kingdom
| | - Luca Porcu
- Department of Oncology, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Milano, Italy
| | - Thimmasettappa Thippeswamy
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, Iowa, USA
| | - Tiina Alapirtti
- Department of Neurology and Rehabilitation, Tampere University Hospital, Tampere, Finland
| | - Jukka Peltola
- Department of Neurology and Rehabilitation, Tampere University Hospital, Tampere, Finland
| | | | - Brian Kevin Park
- Department of Molecular and Clinical Pharmacology, University of Liverpool, Liverpool, United Kingdom
| | - Anthony Guy Marson
- Department of Molecular and Clinical Pharmacology, University of Liverpool, Liverpool, United Kingdom
| | - Daniel James Antoine
- Department of Molecular and Clinical Pharmacology, University of Liverpool, Liverpool, United Kingdom
| | | | - Munir Pirmohamed
- Department of Molecular and Clinical Pharmacology, University of Liverpool, Liverpool, United Kingdom
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38
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He F, Liu B, Meng Q, Sun Y, Wang W, Wang C. Modulation of miR-146a/complement factor H-mediated inflammatory responses in a rat model of temporal lobe epilepsy. Biosci Rep 2016; 36:e00433. [PMID: 27852797 PMCID: PMC5180253 DOI: 10.1042/bsr20160290] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Revised: 11/13/2016] [Accepted: 11/15/2016] [Indexed: 12/12/2022] Open
Abstract
Increasing evidence supports the involvement of inflammatory and immune processes in temporal lobe epilepsy (TLE). miRNAs represent small regulatory RNA molecules that have been shown to act as negative regulators of gene expression controlling different biological processes, including immune system homoeostasis and function. We investigated the expression and cellular distribution of miRNA-146a (miR-146a) in a rat model of TLE. Prominent up-regulation of miR-146a activation was evident in 1 week after status epilepticus (SE) and persisted in the chronic phase. The predicted miR-146a's target complement factor H (CFH) mRNA and protein expression was also down-regulated in TLE rat model. Furthermore, transfection of miR-146a mimics in neuronal and glial cells down-regulated CFH mRNA and protein levels respectively. Luciferase reporter assays demonstrated that miR-146a down-regulated CFH mRNA expression via 3'-UTR pairing. Down-regulating miR-146a by intracerebroventricular injection of antagomir-146a enhanced the hippocampal expression of CFH in TLE model and decreased seizure susceptibility. These findings suggest that immunopathological deficits associated with TLE can in part be explained by a generalized miR-146a-mediated down-regulation of CFH that may contribute to epileptogenesis in a rat model of TLE.
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Affiliation(s)
- Fang He
- Outpatient Department, The 316 Military Hospital, Beijing 100093, China
| | - Bei Liu
- Department of Neurosurgery, Tangdu Hospital, Fourth Military Medical University, Xi'an, Shaanxi 710038, China
| | - Qiang Meng
- Department of Neurosurgery, Tangdu Hospital, Fourth Military Medical University, Xi'an, Shaanxi 710038, China
| | - Yang Sun
- Department of Neurosurgery, Tangdu Hospital, Fourth Military Medical University, Xi'an, Shaanxi 710038, China
| | - Weiwen Wang
- Department of Neurosurgery, Tangdu Hospital, Fourth Military Medical University, Xi'an, Shaanxi 710038, China
| | - Chao Wang
- Department of Neurosurgery, Tangdu Hospital, Fourth Military Medical University, Xi'an, Shaanxi 710038, China
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39
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Schipper S, Aalbers MW, Rijkers K, Lagiere M, Bogaarts JG, Blokland A, Klinkenberg S, Hoogland G, Vles JSH. Accelerated cognitive decline in a rodent model for temporal lobe epilepsy. Epilepsy Behav 2016; 65:33-41. [PMID: 27865173 DOI: 10.1016/j.yebeh.2016.08.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 08/20/2016] [Accepted: 08/25/2016] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Cognitive impairment is frequently observed in patients with temporal lobe epilepsy. It is hypothesized that cumulative seizure exposure causes accelerated cognitive decline in patients with epilepsy. We investigated the influence of seizure frequency on cognitive decline in a rodent model for temporal lobe epilepsy. METHODS Neurobehavioral assessment was performed before and after surgery, after the induction of self-sustaining limbic status epilepticus (SSLSE), and in the chronic phase in which rats experienced recurrent seizures. Furthermore, we assessed potential confounders of memory performance. RESULTS Rats showed a deficit in spatial working memory after the induction of the SSLSE, which endured in the chronic phase. A progressive decline in recognition memory developed in SSLSE rats. Confounding factors were absent. Seizure frequency and also the severity of the status epilepticus were not correlated with the severity of cognitive deficits. SIGNIFICANCE The effect of the seizure frequency on cognitive comorbidity in epilepsy has long been debated, possibly because of confounders such as antiepileptic medication and the heterogeneity of epileptic etiologies. In an animal model of temporal lobe epilepsy, we showed that a decrease in spatial working memory does not relate to the seizure frequency. This suggests for other mechanisms are responsible for memory decline and potentially a common pathophysiology of cognitive deterioration and the occurrence and development of epileptic seizures. Identifying this common denominator will allow development of more targeted interventions treating cognitive decline in patients with epilepsy. The treatment of interictal symptoms will increase the quality of life of many patients with epilepsy.
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Affiliation(s)
- Sandra Schipper
- Department of Clinical Neuroscience, Maastricht University Medical Center, Maastricht, The Netherlands; Faculty of Health Medicine & Life Sciences, School of Mental Health and Neuroscience, Maastricht University Medical Center, Maastricht, The Netherlands.
| | - Marlien W Aalbers
- Faculty of Health Medicine & Life Sciences, School of Mental Health and Neuroscience, Maastricht University Medical Center, Maastricht, The Netherlands; University of Groningen, University Medical Center Groningen, Department of Neurosurgery, The Netherlands
| | - Kim Rijkers
- Faculty of Health Medicine & Life Sciences, School of Mental Health and Neuroscience, Maastricht University Medical Center, Maastricht, The Netherlands; Department of Neurosurgery, Zuyderland Medical Center, Heerlen, The Netherlands
| | - Melanie Lagiere
- Faculty of Health Medicine & Life Sciences, School of Mental Health and Neuroscience, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Jan G Bogaarts
- Department of Clinical Neurophysiology, Maastricht University Medical Center, Maastricht, The Netherlands; Department of Neurosurgery, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Arjan Blokland
- Department of Neuropsychology & Psychopharmacology, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands
| | - Sylvia Klinkenberg
- Department of Clinical Neuroscience, Maastricht University Medical Center, Maastricht, The Netherlands; Faculty of Health Medicine & Life Sciences, School of Mental Health and Neuroscience, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Govert Hoogland
- Faculty of Health Medicine & Life Sciences, School of Mental Health and Neuroscience, Maastricht University Medical Center, Maastricht, The Netherlands; Department of Neurosurgery, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Johan S H Vles
- Department of Clinical Neuroscience, Maastricht University Medical Center, Maastricht, The Netherlands; Faculty of Health Medicine & Life Sciences, School of Mental Health and Neuroscience, Maastricht University Medical Center, Maastricht, The Netherlands
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40
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Brandt C, Rankovic V, Töllner K, Klee R, Bröer S, Löscher W. Refinement of a model of acquired epilepsy for identification and validation of biomarkers of epileptogenesis in rats. Epilepsy Behav 2016; 61:120-131. [PMID: 27343814 DOI: 10.1016/j.yebeh.2016.05.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Revised: 05/09/2016] [Accepted: 05/12/2016] [Indexed: 01/23/2023]
Abstract
In rodent models in which status epilepticus (SE) is used to induce epilepsy, typically most animals develop spontaneous recurrent seizures (SRS). The SE duration for induction of epileptogenesis depends on the type of SE induction. In models with electrical SE induction, the minimum duration of SE to induce epileptogenesis in >90% of animals ranges from 3-4h. A high incidence of epilepsy is an advantage in the search of antiepileptogenic treatments, whereas it is a disadvantage in the search for biomarkers of epileptogenesis, because it does not allow a comparison of potential biomarkers in animals that either develop or do not develop epilepsy. The aim of this project was the refinement of an established SE rat model so that only ~50% of the animals develop epilepsy. For this purpose, we used an electrical model of SE induction, in which a self-sustained SE develops after prolonged stimulation of the basolateral amygdala. Previous experiments had shown that the majority of rats develop SRS after 4-h SE in this model so that the SE reduced duration to 2.5h by administering diazepam. This resulted in epilepsy development in only 50% of rats, thus reaching the goal of the project. The latent period to onset of SRS wa s >2weeks in most rats. Development of epilepsy could be predicted in most rats by behavioral hyperexcitability, whereas seizure threshold did not differentiate rats that did and did not develop SRS. The refined SE model may offer a platform to identify and validate biomarkers of epileptogenesis.
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Affiliation(s)
- Claudia Brandt
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, 30559 Hannover, Germany; Center for Systems Neuroscience, 30559 Hannover, Germany
| | - Vladan Rankovic
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, 30559 Hannover, Germany; Center for Systems Neuroscience, 30559 Hannover, Germany
| | - Kathrin Töllner
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, 30559 Hannover, Germany; Center for Systems Neuroscience, 30559 Hannover, Germany
| | - Rebecca Klee
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, 30559 Hannover, Germany; Center for Systems Neuroscience, 30559 Hannover, Germany
| | - Sonja Bröer
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, 30559 Hannover, Germany; Center for Systems Neuroscience, 30559 Hannover, Germany
| | - Wolfgang Löscher
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, 30559 Hannover, Germany; Center for Systems Neuroscience, 30559 Hannover, Germany.
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41
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Sharma AK, Reams RY, Jordan WH, Miller MA, Thacker HL, Snyder PW. Mesial Temporal Lobe Epilepsy: Pathogenesis, Induced Rodent Models and Lesions. Toxicol Pathol 2016; 35:984-99. [PMID: 18098044 DOI: 10.1080/01926230701748305] [Citation(s) in RCA: 195] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Mesial temporal lobe epilepsy (MTLE), the most common epilepsy in adults, is generally intractable and is suspected to be the result of recurrent excitation or inhibition circuitry. Recurrent excitation and the development of seizures have been associated with aberrant mossy fiber sprouting in the hippocampus. Of the animal models developed to investigate the pathogenesis of MTLE, post-status epilepticus models have received the greatest acceptance because they are characterized by a latency period, the development of spontaneous motor seizures, and a spectrum of lesions like those of MTLE. Among post-status epilepticus models, induction of systemic kainic acid or pilocarpine-induced epilepsy is less labor-intensive than electrical-stimulation models and these models mirror the clinicopathologic features of MTLE more closely than do kindling, tetanus toxin, hyperthermia, post-traumatic, and perinatal hypoxia/ischemia models. Unfortunately, spontaneous motor seizures do not develop in kindling or adult hyperthermia models and are not a consistent finding in tetanus toxin-induced or perinatal hypoxia/ischemia models. This review presents the mechanistic hypotheses for seizure induction, means of model induction, and associated pathology, especially as compared to MTLE patients. Animal models are valuable tools not only to study the pathogenesis of MTLE, but also to evaluate potential antiepileptogenic drugs.
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Affiliation(s)
- Alok K. Sharma
- Department of Comparative Pathobiology, Purdue University, West Lafayette, IN 47907, USA
- Department of Pathology, Covance Laboratories Inc., Madison, WI, 53704, USA
| | - Rachel Y. Reams
- Department of Pathology, Lilly Research Laboratories, Division of Eli Lilly and Co., Greenfield, IN, 46140, USA
| | - William H. Jordan
- Department of Pathology, Lilly Research Laboratories, Division of Eli Lilly and Co., Greenfield, IN, 46140, USA
| | - Margaret A. Miller
- Department of Comparative Pathobiology, Purdue University, West Lafayette, IN 47907, USA
| | - H. Leon Thacker
- Department of Comparative Pathobiology, Purdue University, West Lafayette, IN 47907, USA
| | - Paul W. Snyder
- Department of Comparative Pathobiology, Purdue University, West Lafayette, IN 47907, USA
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42
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Hong S, Lee P, Baraban SC, Lee LP. A Novel Long-term, Multi-Channel and Non-invasive Electrophysiology Platform for Zebrafish. Sci Rep 2016; 6:28248. [PMID: 27305978 PMCID: PMC4910293 DOI: 10.1038/srep28248] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 06/01/2016] [Indexed: 01/03/2023] Open
Abstract
Zebrafish are a popular vertebrate model for human neurological disorders and drug discovery. Although fecundity, breeding convenience, genetic homology and optical transparency have been key advantages, laborious and invasive procedures are required for electrophysiological studies. Using an electrode-integrated microfluidic system, here we demonstrate a novel multichannel electrophysiology unit to record multiple zebrafish. This platform allows spontaneous alignment of zebrafish and maintains, over days, close contact between head and multiple surface electrodes, enabling non-invasive long-term electroencephalographic recording. First, we demonstrate that electrographic seizure events, induced by pentylenetetrazole, can be reliably distinguished from eye or tail movement artifacts, and quantifiably identified with our unique algorithm. Second, we show long-term monitoring during epileptogenic progression in a scn1lab mutant recapitulating human Dravet syndrome. Third, we provide an example of cross-over pharmacology antiepileptic drug testing. Such promising features of this integrated microfluidic platform will greatly facilitate high-throughput drug screening and electrophysiological characterization of epileptic zebrafish.
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Affiliation(s)
- SoonGweon Hong
- Department of Bioengineering Engineering, University of California, Berkeley, CA 94720, USA.,Berkeley Sensor and Actuator Center, University of California, Berkeley, CA 94720, USA
| | - Philip Lee
- Department of Bioengineering Engineering, University of California, Berkeley, CA 94720, USA
| | - Scott C Baraban
- Epilepsy Research Laboratory, Department of Neurological Surgery, University of California at San Francisco, USA, CA 94143, USA.,Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California at San Francisco, USA, CA 94143, USA
| | - Luke P Lee
- Department of Bioengineering Engineering, University of California, Berkeley, CA 94720, USA.,Berkeley Sensor and Actuator Center, University of California, Berkeley, CA 94720, USA.,Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, CA 94720, USA.,Biophysics Graduate Program, University of California, Berkeley, CA 94720, USA
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43
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Alexander A, Maroso M, Soltesz I. Organization and control of epileptic circuits in temporal lobe epilepsy. PROGRESS IN BRAIN RESEARCH 2016; 226:127-54. [PMID: 27323941 PMCID: PMC5140277 DOI: 10.1016/bs.pbr.2016.04.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
When studying the pathological mechanisms of epilepsy, there are a seemingly endless number of approaches from the ultrastructural level-receptor expression by EM-to the behavioral level-comorbid depression in behaving animals. Epilepsy is characterized as a disorder of recurrent seizures, which are defined as "a transient occurrence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain" (Fisher et al., 2005). Such abnormal activity typically does not occur in a single isolated neuron; rather, it results from pathological activity in large groups-or circuits-of neurons. Here we choose to focus on two aspects of aberrant circuits in temporal lobe epilepsy: their organization and potential mechanisms to control these pathological circuits. We also look at two scales: microcircuits, ie, the relationship between individual neurons or small groups of similar neurons, and macrocircuits, ie, the organization of large-scale brain regions. We begin by summarizing the large body of literature that describes the stereotypical anatomical changes in the temporal lobe-ie, the anatomical basis of alterations in microcircuitry. We then offer a brief introduction to graph theory and describe how this type of mathematical analysis, in combination with computational neuroscience techniques and using parameters obtained from experimental data, can be used to postulate how microcircuit alterations may lead to seizures. We then zoom out and look at the changes which are seen over large whole-brain networks in patients and animal models, and finally we look to the future.
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Affiliation(s)
- A Alexander
- Stanford University, Stanford, CA, United States
| | - M Maroso
- Stanford University, Stanford, CA, United States
| | - I Soltesz
- Stanford University, Stanford, CA, United States.
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Wang X, Song X, Wu L, Nadler JV, Zhan RZ. Persistent Hyperactivity of Hippocampal Dentate Interneurons After a Silent Period in the Rat Pilocarpine Model of Epilepsy. Front Cell Neurosci 2016; 10:94. [PMID: 27092056 PMCID: PMC4824773 DOI: 10.3389/fncel.2016.00094] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 03/24/2016] [Indexed: 12/15/2022] Open
Abstract
Profile of GABAergic interneuron activity after pilocarpine-induced status epilepticus (SE) was examined in the rat hippocampal dentate gyrus by analyzing immediate early gene expression and recording spontaneous firing at near resting membrane potential (REM). SE for exact 2 h or more than 2 h was induced in the male Sprague-Dawley rats by an intraperitoneal injection of pilocarpine. Expression of immediate early genes (IEGs) was examined at 1 h, 1 week, 2 weeks or more than 10 weeks after SE. For animals to be examined at 1 h after SE, SE lasted for exact 2 h was terminated by an intraperitoneal injection of diazepam. Spontaneous firing at near the REM was recorded in interneurons located along the border between the granule cell layer and the hilus more than 10 weeks after SE. Results showed that both c-fos and activity-regulated cytoskeleton associated protein (Arc) in hilar GABAergic interneurons were up-regulated after SE in a biphasic manner; they were increased at 1 h and more than 2 weeks, but not at 1 week after SE. Ten weeks after SE, nearly 60% of hilar GABAergic cells expressed c-fos. With the exception of calretinin (CR)-positive cells, percentages of hilar neuronal nitric oxide synthase (nNOS)-, neuropeptide Y (NPY)-, parvalbumin (PV)-, and somatostatin (SOM)-positive cells with c-fos expression are significantly higher than those of controls more than 10 weeks after SE. Without the REM to be more depolarizing and changed threshold potential level in SE-induced rats, cell-attached recording revealed that nearly 90% of hilar interneurons fired spontaneously at near the REM while only 22% of the same cell population did so in the controls. In conclusion, pilocarpine-induced SE eventually leads to a state in which surviving dentate GABAergic interneurons become hyperactive with a subtype-dependent manner; this implies that a fragile balance between excitation and inhibition exists in the dentate gyrus and in addition, the activity-dependent up-regulation of IEGs may underlie plastic changes seen in some types of GABAergic cells in the pilocarpine model of epilepsy.
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Affiliation(s)
- Xiaochen Wang
- Department of Physiology, Shandong University School of Medicine Jinan, China
| | - Xinyu Song
- Department of Respiratory Medicine, Affiliated Hospital of Binzhou Medical University Binzhou, Shandong, China
| | - Lin Wu
- Department of Physiology, Shandong University School of Medicine Jinan, China
| | - J Victor Nadler
- Department of Pharmacology and Cancer Biology, Duke University Medical Center Durham, NC, USA
| | - Ren-Zhi Zhan
- Department of Physiology, Shandong University School of Medicine Jinan, China
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Abstract
Pathological high-frequency oscillations (HFOs) (80-800 Hz) are considered biomarkers of epileptogenic tissue, but the underlying complex neuronal events are not well understood. Here, we identify and discuss several outstanding issues or conundrums in regards to the recording, analysis, and interpretation of HFOs in the epileptic brain to critically highlight what is known and what is not about these enigmatic events. High-frequency oscillations reflect a range of neuronal processes contributing to overlapping frequencies from the lower 80 Hz to the very fast spectral frequency bands. Given their complex neuronal nature, HFOs are extremely sensitive to recording conditions and analytical approaches. We provide a list of recommendations that could help to obtain comparable HFO signals in clinical and basic epilepsy research. Adopting basic standards will facilitate data sharing and interpretation that collectively will aid in understanding the role of HFOs in health and disease for translational purpose.
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Umpierre AD, Bennett IV, Nebeker LD, Newell TG, Tian BB, Thomson KE, White HS, White JA, Wilcox KS. Repeated low-dose kainate administration in C57BL/6J mice produces temporal lobe epilepsy pathology but infrequent spontaneous seizures. Exp Neurol 2016; 279:116-126. [PMID: 26896834 DOI: 10.1016/j.expneurol.2016.02.014] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Revised: 01/29/2016] [Accepted: 02/15/2016] [Indexed: 12/31/2022]
Abstract
More efficient or translationally relevant approaches are needed to model acquired temporal lobe epilepsy (TLE) in genetically tractable mice. The high costs associated with breeding and maintaining transgenic, knock-in, or knock-out lines place a high value on the efficiency of induction and animal survivability. Herein, we describe our approaches to model acquired epilepsy in C57BL/6J mice using repeated, low-dose kainate (KA) administration paradigms. Four paradigms (i.p.) were tested for their ability to induce status epilepticus (SE), temporal lobe pathology, and the development of epilepsy. All four paradigms reliably induce behavioral and/or electrographic SE without mortality over a 7d period. Two of the four paradigms investigated produce features indicative of TLE pathology, including hippocampal cell death, widespread astrogliosis, and astrocyte expression of mGluR5, a feature commonly reported in TLE models. Three of the investigated paradigms were able to produce aberrant electrographic features, such as interictal spiking in cortex. However, only one paradigm, previously published by others, produces spontaneous recurrent seizures over an eight week period. Presentation of spontaneous seizures is rare (N=2/14), with epilepsy preferentially developing in animals having a high number of seizures during SE. Overall, repeated, low-dose KA administration improves the efficiency and pathological relevance of a systemic KA insult, but does not produce a robust epilepsy phenotype under the experimental paradigms described herein.
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Affiliation(s)
- Anthony D Umpierre
- Interdepartmental Program in Neuroscience, University of Utah, 401 MREB, 20N. 1900E, Salt Lake City, UT 84132, United States.
| | - Isaiah V Bennett
- Dept. of Pharmacology & Toxicology, University of Utah, College of Pharmacy, 30N. 1900E, Salt Lake City, UT 84112, United States.
| | - Lismore D Nebeker
- Dept. of Pharmacology & Toxicology, University of Utah, College of Pharmacy, 30N. 1900E, Salt Lake City, UT 84112, United States.
| | - Thomas G Newell
- Anticonvulsant Drug Development Program, University of Utah, 417 Wakara Way, Suite 3211, Salt Lake City, UT 84108, United States; Dept. of Bioengineering, University of Utah, 36S. Wasatch Drive, Rm. 3100, Salt Lake City, UT 84112, United States.
| | - Bruce B Tian
- Dept. of Pharmacology & Toxicology, University of Utah, College of Pharmacy, 30N. 1900E, Salt Lake City, UT 84112, United States.
| | - Kyle E Thomson
- Anticonvulsant Drug Development Program, University of Utah, 417 Wakara Way, Suite 3211, Salt Lake City, UT 84108, United States; Dept. of Bioengineering, University of Utah, 36S. Wasatch Drive, Rm. 3100, Salt Lake City, UT 84112, United States.
| | - H Steve White
- Dept. of Pharmacology & Toxicology, University of Utah, College of Pharmacy, 30N. 1900E, Salt Lake City, UT 84112, United States; Anticonvulsant Drug Development Program, University of Utah, 417 Wakara Way, Suite 3211, Salt Lake City, UT 84108, United States; Department of Pharmacy, University of Washington, Box 357630, H375 Health Science Building, Seattle, WA 98195, United States.
| | - John A White
- Dept. of Biomedical Engineering, Boston University, 44 Cummington Mall, Rm. 403, Boston, MA 02215, United States.
| | - Karen S Wilcox
- Interdepartmental Program in Neuroscience, University of Utah, 401 MREB, 20N. 1900E, Salt Lake City, UT 84132, United States; Dept. of Pharmacology & Toxicology, University of Utah, College of Pharmacy, 30N. 1900E, Salt Lake City, UT 84112, United States; Anticonvulsant Drug Development Program, University of Utah, 417 Wakara Way, Suite 3211, Salt Lake City, UT 84108, United States.
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47
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Collins SA, Huff C, Chiaia N, Gudelsky GA, Yamamoto BK. 3,4-methylenedioxymethamphetamine increases excitability in the dentate gyrus: role of 5HT2A receptor-induced PGE2 signaling. J Neurochem 2016; 136:1074-84. [PMID: 26670377 DOI: 10.1111/jnc.13493] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Revised: 12/04/2015] [Accepted: 12/10/2015] [Indexed: 12/12/2022]
Abstract
3,4-methylenedioxymethamphetamine (MDMA) is a widely abused psychostimulant, which causes release of serotonin in various forebrain regions. Recently, we reported that MDMA increases extracellular glutamate concentrations in the dentate gyrus, via activation of 5HT2A receptors. We examined the role of prostaglandin signaling in mediating the effects of 5HT2A receptor activation on the increases in extracellular glutamate and the subsequent long-term loss of parvalbumin interneurons in the dentate gyrus caused by MDMA. Administration of MDMA into the dentate gyrus of rats increased PGE2 concentrations which was prevented by coadministration of MDL100907, a 5HT2A receptor antagonist. MDMA-induced increases in extracellular glutamate were inhibited by local administration of SC-51089, an inhibitor of the EP1 prostaglandin receptor. Systemic administration of SC-51089 during injections of MDMA prevented the decreases in parvalbumin interneurons observed 10 days later. The loss of parvalbumin immunoreactivity after MDMA exposure coincided with a decrease in paired-pulse inhibition and afterdischarge threshold in the dentate gyrus. These changes were prevented by inhibition of EP1 and 5HT2A receptors during MDMA. Additional experiments revealed an increased susceptibility to kainic acid-induced seizures in MDMA-treated rats, which could be prevented with SC51089 treatments during MDMA exposure. Overall, these findings suggest that 5HT2A receptors mediate MDMA-induced PGE2 signaling and subsequent increases in glutamate. This signaling mediates parvalbumin cell losses as well as physiologic changes in the dentate gyrus, suggesting that the lack of the inhibition provided by these neurons increases the excitability within the dentate gyrus of MDMA-treated rats. We hypothesized that the widely abused psychostimulant MDMA causes a loss of parvalbumin (PV) cells and increases excitability in the dentate gyrus. MDMA increases serotonin (5HT) release and activates 5HT2A receptors. The increased activation of 5HT2A receptors promotes the production of prostaglandin E2 (PGE2) and subsequent activation of EP1 receptors in the dentate gyrus. EP1 receptor activation leads to eventual excitotoxicity and loss of PV interneurons resulting in reduced inhibition and lowered seizure threshold resulting in increased seizure susceptibility.
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Affiliation(s)
- Stuart A Collins
- Department of Neurosciences, The University of Toledo, Toledo, Ohio, USA
| | - Courtney Huff
- James Winkle College of Pharmacy, University of Cincinnati, Cincinnati, Ohio, USA
| | - Nicolas Chiaia
- Department of Neurosciences, The University of Toledo, Toledo, Ohio, USA
| | - Gary A Gudelsky
- James Winkle College of Pharmacy, University of Cincinnati, Cincinnati, Ohio, USA
| | - Bryan K Yamamoto
- Department of Neurosciences, The University of Toledo, Toledo, Ohio, USA.,Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, Indiana, USA
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48
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Temporal progression of evoked field potentials in neocortical slices after unilateral hypoxia-ischemia in perinatal rats: Correlation with cortical epileptogenesis. Neuroscience 2015; 316:232-48. [PMID: 26724579 DOI: 10.1016/j.neuroscience.2015.12.029] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Revised: 12/14/2015] [Accepted: 12/14/2015] [Indexed: 11/20/2022]
Abstract
Infarcts of the neonatal cerebral cortex can lead to progressive epilepsy, which is characterized by time-dependent increases in seizure frequency after the infarct and by shifts in seizure-onset zones from focal to multi-focal. Using a rat model of unilateral perinatal hypoxia-ischemia (PHI), where long-term seizure monitoring had previously demonstrated progressive epilepsy, evoked field potentials (EFPs) were recorded in layers II/III of coronal neocortical slices to analyze the underlying time-dependent, network-level alterations ipsilateral vs. contralateral to the infarct. At 3weeks after PHI, EFPs ipsilateral to the infarct were normal in artificial cerebrospinal fluid (ACSF); however, after blocking GABAA receptors with bicuculline methiodide (BMI, 30μM), the slices with an infarct were more hyperexcitable than slices without an infarct. At 3weeks, contralateral PHI slices had responses indistinguishable from controls. Six months after PHI in normal ACSF, both ipsi- and contralateral slices from rats with cortical infarcts showed prolonged afterdischarges, which were only slightly augmented in BMI. These data suggest that the early changes after PHI are localized to the ipsilateral infarcted cortex and masked by GABA-mediated inhibition; however, after 6months, progressive epileptogenesis results in generation of robust bilateral hyperexcitability. Because these afterdischarges were only slightly prolonged by BMI, a time-dependent reduction of GABAergic transmission is hypothesized to contribute to the pronounced hyperexcitability at 6months. These changes in the EFPs coincide with the seizure semiology of the epilepsy and therefore offer an opportunity to study the mechanisms underlying this form of progressive pediatric epilepsy.
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49
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Shen HY, van Vliet EA, Bright KA, Hanthorn M, Lytle NK, Gorter J, Aronica E, Boison D. Glycine transporter 1 is a target for the treatment of epilepsy. Neuropharmacology 2015; 99:554-65. [PMID: 26302655 PMCID: PMC4655139 DOI: 10.1016/j.neuropharm.2015.08.031] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 07/27/2015] [Accepted: 08/19/2015] [Indexed: 11/17/2022]
Abstract
Glycine is the major inhibitory neurotransmitter in brainstem and spinal cord, whereas in hippocampus glycine exerts dual modulatory roles on strychnine-sensitive glycine receptors and on the strychnine-insensitive glycineB site of the N-methyl-D-aspartate receptor (NMDAR). In hippocampus, the synaptic availability of glycine is largely under control of glycine transporter 1 (GlyT1). Since epilepsy is a disorder of disrupted network homeostasis affecting the equilibrium of various neurotransmitters and neuromodulators, we hypothesized that changes in hippocampal GlyT1 expression and resulting disruption of glycine homeostasis might be implicated in the pathophysiology of epilepsy. Using two different rodent models of temporal lobe epilepsy (TLE)--the intrahippocampal kainic acid model of TLE in mice, and the rat model of tetanic stimulation-induced TLE--we first demonstrated robust overexpression of GlyT1 in the hippocampal formation, suggesting dysfunctional glycine signaling in epilepsy. Overexpression of GlyT1 in the hippocampal formation was corroborated in human TLE samples by quantitative real time PCR. In support of a role of dysfunctional glycine signaling in the pathophysiology of epilepsy, both the genetic deletion of GlyT1 in hippocampus and the GlyT1 inhibitor LY2365109 increased seizure thresholds in mice. Importantly, chronic seizures in the mouse model of TLE were robustly suppressed by systemic administration of the GlyT1 inhibitor LY2365109. We conclude that GlyT1 overexpression in the epileptic brain constitutes a new target for therapeutic intervention, and that GlyT1 inhibitors constitute a new class of antiictogenic drugs. These findings are of translational value since GlyT1 inhibitors are already in clinical development to treat cognitive symptoms in schizophrenia.
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Affiliation(s)
- Hai-Ying Shen
- Robert Stone Dow Neurobiology Laboratories, Legacy Research Institute, Portland, OR 97232, USA
| | - Erwin A van Vliet
- Department of (Neuro)Pathology, Academic Medical Center, University of Amsterdam, The Netherlands
| | - Kerry-Ann Bright
- Robert Stone Dow Neurobiology Laboratories, Legacy Research Institute, Portland, OR 97232, USA
| | - Marissa Hanthorn
- Robert Stone Dow Neurobiology Laboratories, Legacy Research Institute, Portland, OR 97232, USA
| | - Nikki K Lytle
- Robert Stone Dow Neurobiology Laboratories, Legacy Research Institute, Portland, OR 97232, USA
| | - Jan Gorter
- Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, The Netherlands
| | - Eleonora Aronica
- Department of (Neuro)Pathology, Academic Medical Center, University of Amsterdam, The Netherlands; Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, The Netherlands; SEIN - Stichting Epilepsie Instellingen Nederland, Heemstede, The Netherlands
| | - Detlev Boison
- Robert Stone Dow Neurobiology Laboratories, Legacy Research Institute, Portland, OR 97232, USA.
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50
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Löscher W, Hirsch LJ, Schmidt D. The enigma of the latent period in the development of symptomatic acquired epilepsy - Traditional view versus new concepts. Epilepsy Behav 2015; 52:78-92. [PMID: 26409135 DOI: 10.1016/j.yebeh.2015.08.037] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Accepted: 08/30/2015] [Indexed: 01/21/2023]
Abstract
A widely accepted hypothesis holds that there is a seizure-free, pre-epileptic state, termed the "latent period", between a brain insult, such as traumatic brain injury or stroke, and the onset of symptomatic epilepsy, during which a cascade of structural, molecular, and functional alterations gradually mediates the process of epileptogenesis. This review, based on recent data from both animal models and patients with different types of brain injury, proposes that epileptogenesis and often subclinical epilepsy can start immediately after brain injury without any appreciable latent period. Even though the latent period has traditionally been the cornerstone concept representing epileptogenesis, we suggest that the evidence for the existence of a latent period is spotty both for animal models and human epilepsy. Knowing whether a latent period exists or not is important for our understanding of epileptogenesis and for the discovery and the trial design of antiepileptogenic agents. The development of antiepileptogenic treatments to prevent epilepsy in patients at risk from a brain insult is a major unmet clinical need.
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Affiliation(s)
- Wolfgang Löscher
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine, 30559 Hannover, Germany; Center for Systems Neuroscience, 30559 Hannover, Germany.
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