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Yonan JM, Chen KD, Baram TZ, Steward O. PTEN DELETION IN THE ADULT DENTATE GYRUS INDUCES EPILEPSY. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.07.606938. [PMID: 39149280 PMCID: PMC11326251 DOI: 10.1101/2024.08.07.606938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 08/17/2024]
Abstract
Embryonic and early postnatal promotor-driven deletion of the phosphatase and tensin homolog (PTEN) gene results in neuronal hypertrophy, hyperexcitable circuitry and development of spontaneous seizures in adulthood. We previously documented that focal, vector-mediated PTEN deletion in mature granule cells of adult dentate gyrus triggers dramatic growth of cell bodies, dendrites, and axons, similar to that seen with early postnatal PTEN deletion. Here, we assess the functional consequences of focal, adult PTEN deletion, focusing on its pro-epileptogenic potential. PTEN deletion was accomplished by injecting AAV-Cre either bilaterally or unilaterally into the dentate gyrus of double transgenic PTEN-floxed, ROSA-reporter mice. Hippocampal recording electrodes were implanted for continuous digital EEG with concurrent video recordings in the home cage. Electrographic seizures and epileptiform spikes were assessed manually by two investigators, and corelated with concurrent videos. Spontaneous electrographic and behavioral seizures appeared after focal PTEN deletion in adult dentate granule cells, commencing around 2 months post-AAV-Cre injection. Seizures occurred in the majority of mice with unilateral or bilateral PTEN deletion and led to death in several cases. PTEN-deletion provoked epilepsy was not associated with apparent hippocampal neuron death; supra-granular mossy fiber sprouting was observed in a few mice. In summary, focal, unilateral deletion of PTEN in the adult dentate gyrus suffices to provoke time-dependent emergence of a hyperexcitable circuit generating hippocampus-origin, generalizing spontaneous seizures, providing a novel model for studies of adult-onset epileptogenesis.
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Affiliation(s)
- Jennifer M Yonan
- Reeve-Irvine Research Center, Departments of Anatomy & Neurobiology, Neurobiology & Behavior, Neurosurgery, Pediatrics and Neurology, Center for the Neurobiology of Learning and Memory, University of California at Irvine, Irvine, CA 92697
| | - Kevin D Chen
- Reeve-Irvine Research Center, Departments of Anatomy & Neurobiology, Neurobiology & Behavior, Neurosurgery, Pediatrics and Neurology, Center for the Neurobiology of Learning and Memory, University of California at Irvine, Irvine, CA 92697
| | - Tallie Z Baram
- Reeve-Irvine Research Center, Departments of Anatomy & Neurobiology, Neurobiology & Behavior, Neurosurgery, Pediatrics and Neurology, Center for the Neurobiology of Learning and Memory, University of California at Irvine, Irvine, CA 92697
| | - Oswald Steward
- Reeve-Irvine Research Center, Departments of Anatomy & Neurobiology, Neurobiology & Behavior, Neurosurgery, Pediatrics and Neurology, Center for the Neurobiology of Learning and Memory, University of California at Irvine, Irvine, CA 92697
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2
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Wu C, Xie J, Yao Q, Song Y, Yang G, Zhao J, Zhang R, Wang T, Jiang X, Cai X, Gao Y. Intrahippocampal Supramolecular Assemblies Directed Bioorthogonal Liberation of Neurotransmitters to Suppress Seizures in Freely Moving Mice. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2314310. [PMID: 38655719 DOI: 10.1002/adma.202314310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 04/22/2024] [Indexed: 04/26/2024]
Abstract
The precise delivery of anti-seizure medications (ASM) to epileptic loci remains the major challenge to treat epilepsy without causing adverse drug reactions. The unprovoked nature of epileptic seizures raises the additional need to release ASMs in a spatiotemporal controlled manner. Targeting the oxidative stress in epileptic lesions, here the reactive oxygen species (ROS) induced in situ supramolecular assemblies that synergized bioorthogonal reactions to deliver inhibitory neurotransmitter (GABA) on-demand, are developed. Tetrazine-bearing assembly precursors undergo oxidation and selectively self-assemble under pathological conditions inside primary neurons and mice brains. Assemblies induce local accumulation of tetrazine in the hippocampus CA3 region, which allows the subsequent bioorthogonal release of inhibitory neurotransmitters. For induced acute seizures, the sustained release of GABA extends the suppression than the direct supply of GABA. In the model of permanent damage of CA3, bioorthogonal ligation on assemblies provides a reservoir of GABA that behaves prompt release upon 365 nm irradiation. Incorporated with the state-of-the-art microelectrode arrays, it is elucidated that the bioorthogonal release of GABA shifts the neuron spike waveforms to suppress seizures at the single-neuron precision. The strategy of in situ supramolecular assemblies-directed bioorthogonal prodrug activation shall be promising for the effective delivery of ASMs to treat epilepsy.
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Affiliation(s)
- Chengling Wu
- State Key Laboratory of Chemical Resource Engineering, Beijing Laboratory of Biomedical Materials, College of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing, 100029, China
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, China
- CAS Key Laboratory of Biomedical Effects of Nanomaterials and Nanosafety, National Center for Nanoscience and Technology, Beijing, 100190, China
| | - Jingyu Xie
- State Key Laboratory of Transducer Technology, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing, 100190, China
- School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Qingxin Yao
- State Key Laboratory of Chemical Resource Engineering, Beijing Laboratory of Biomedical Materials, College of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing, 100029, China
- CAS Key Laboratory of Biomedical Effects of Nanomaterials and Nanosafety, National Center for Nanoscience and Technology, Beijing, 100190, China
| | - Yilin Song
- State Key Laboratory of Transducer Technology, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing, 100190, China
- School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Gucheng Yang
- State Key Laboratory of Transducer Technology, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing, 100190, China
- School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jie Zhao
- CAS Key Laboratory of Biomedical Effects of Nanomaterials and Nanosafety, National Center for Nanoscience and Technology, Beijing, 100190, China
| | - Ruijia Zhang
- State Key Laboratory of Chemical Resource Engineering, Beijing Laboratory of Biomedical Materials, College of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing, 100029, China
- CAS Key Laboratory of Biomedical Effects of Nanomaterials and Nanosafety, National Center for Nanoscience and Technology, Beijing, 100190, China
| | - Ting Wang
- CAS Key Laboratory of Biomedical Effects of Nanomaterials and Nanosafety, National Center for Nanoscience and Technology, Beijing, 100190, China
| | - Xingyu Jiang
- Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
| | - Xinxia Cai
- State Key Laboratory of Transducer Technology, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing, 100190, China
- School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yuan Gao
- State Key Laboratory of Chemical Resource Engineering, Beijing Laboratory of Biomedical Materials, College of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing, 100029, China
- CAS Key Laboratory of Biomedical Effects of Nanomaterials and Nanosafety, National Center for Nanoscience and Technology, Beijing, 100190, China
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Patel DC, Swift N, Tewari BP, Browning JL, Prim C, Chaunsali L, Kimbrough IF, Olsen ML, Sontheimer H. Increased expression of chondroitin sulfate proteoglycans in dentate gyrus and amygdala causes postinfectious seizures. Brain 2024; 147:1856-1870. [PMID: 38146224 PMCID: PMC11068111 DOI: 10.1093/brain/awad430] [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: 06/27/2023] [Revised: 10/05/2023] [Accepted: 12/08/2023] [Indexed: 12/27/2023] Open
Abstract
Alterations in the extracellular matrix are common in patients with epilepsy and animal models of epilepsy, yet whether they are the cause or consequence of seizures and epilepsy development is unknown. Using Theiler's murine encephalomyelitis virus (TMEV) infection-induced model of acquired epilepsy, we found de novo expression of chondroitin sulfate proteoglycans (CSPGs), a major extracellular matrix component, in dentate gyrus (DG) and amygdala exclusively in mice with acute seizures. Preventing the synthesis of CSPGs specifically in DG and amygdala by deletion of the major CSPG aggrecan reduced seizure burden. Patch-clamp recordings from dentate granule cells revealed enhanced intrinsic and synaptic excitability in seizing mice that was significantly ameliorated by aggrecan deletion. In situ experiments suggested that dentate granule cell hyperexcitability results from negatively charged CSPGs increasing stationary cations on the membrane, thereby depolarizing neurons, increasing their intrinsic and synaptic excitability. These results show increased expression of CSPGs in the DG and amygdala as one of the causal factors for TMEV-induced acute seizures. We also show identical changes in CSPGs in pilocarpine-induced epilepsy, suggesting that enhanced CSPGs in the DG and amygdala may be a common ictogenic factor and potential therapeutic target.
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Affiliation(s)
- Dipan C Patel
- Department of Neuroscience, School of Medicine, University of Virginia, Charlottesville, VA 22903, USA
| | - Nathaniel Swift
- School of Neuroscience, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
| | - Bhanu P Tewari
- Department of Neuroscience, School of Medicine, University of Virginia, Charlottesville, VA 22903, USA
| | - Jack L Browning
- School of Neuroscience, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
| | - Courtney Prim
- Department of Neuroscience, School of Medicine, University of Virginia, Charlottesville, VA 22903, USA
| | - Lata Chaunsali
- Department of Neuroscience, School of Medicine, University of Virginia, Charlottesville, VA 22903, USA
| | - Ian F Kimbrough
- Department of Neuroscience, School of Medicine, University of Virginia, Charlottesville, VA 22903, USA
| | - Michelle L Olsen
- School of Neuroscience, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
| | - Harald Sontheimer
- Department of Neuroscience, School of Medicine, University of Virginia, Charlottesville, VA 22903, USA
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Feng Y, Diego KS, Dong Z, Wick ZC, Page-Harley L, Page-Harley V, Schnipper J, Lamsifer SI, Pennington ZT, Vetere LM, Philipsberg PA, Soler I, Jurkowski A, Rosado CJ, Khan NN, Cai DJ, Shuman T. Distinct changes to hippocampal and medial entorhinal circuits emerge across the progression of cognitive deficits in epilepsy. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.12.584697. [PMID: 38559224 PMCID: PMC10979962 DOI: 10.1101/2024.03.12.584697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Temporal lobe epilepsy (TLE) causes pervasive and progressive memory impairments, yet the specific circuit changes that drive these deficits remain unclear. To investigate how hippocampal-entorhinal dysfunction contributes to progressive memory deficits in epilepsy, we performed simultaneous in vivo electrophysiology in hippocampus (HPC) and medial entorhinal cortex (MEC) of control and epileptic mice 3 or 8 weeks after pilocarpine-induced status epilepticus (Pilo-SE). We found that HPC synchronization deficits (including reduced theta power, coherence, and altered interneuron spike timing) emerged within 3 weeks of Pilo-SE, aligning with early-onset, relatively subtle memory deficits. In contrast, abnormal synchronization within MEC and between HPC-MEC emerged later, by 8 weeks after Pilo-SE, when spatial memory impairment was more severe. Furthermore, a distinct subpopulation of MEC layer 3 excitatory neurons (active at theta troughs) was specifically impaired in epileptic mice. Together, these findings suggest that hippocampal-entorhinal circuit dysfunction accumulates and shifts as cognitive impairment progresses in TLE.
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Affiliation(s)
- Yu Feng
- Icahn School of Medicine at Mount Sinai, New York, NY
| | | | - Zhe Dong
- Icahn School of Medicine at Mount Sinai, New York, NY
| | | | | | | | | | | | | | | | | | - Ivan Soler
- Icahn School of Medicine at Mount Sinai, New York, NY
| | | | | | - Nadia N Khan
- Icahn School of Medicine at Mount Sinai, New York, NY
| | - Denise J Cai
- Icahn School of Medicine at Mount Sinai, New York, NY
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Luna-Munguia H, Gasca-Martinez D, Garay-Cortes A, Coutiño D, Regalado M, de Los Rios E, Villaseñor P, Hidalgo-Flores F, Flores-Guapo K, Benito BY, Concha L. Selective Medial Septum Lesions in Healthy Rats Induce Longitudinal Changes in Microstructure of Limbic Regions, Behavioral Alterations, and Increased Susceptibility to Status Epilepticus. Mol Neurobiol 2024:10.1007/s12035-024-04069-9. [PMID: 38443731 DOI: 10.1007/s12035-024-04069-9] [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: 09/25/2023] [Accepted: 02/26/2024] [Indexed: 03/07/2024]
Abstract
Septo-hippocampal pathway, crucial for physiological functions and involved in epilepsy. Clinical monitoring during epileptogenesis is complicated. We aim to evaluate tissue changes after lesioning the medial septum (MS) of normal rats and assess how the depletion of specific neuronal populations alters the animals' behavior and susceptibility to establishing a pilocarpine-induced status epilepticus. Male Sprague-Dawley rats were injected into the MS with vehicle or saporins (to deplete GABAergic or cholinergic neurons; n = 16 per group). Thirty-two animals were used for diffusion tensor imaging (DTI); scanned before surgery and 14 and 49 days post-injection. Fractional anisotropy and apparent diffusion coefficient were evaluated in the fimbria, dorsal hippocampus, ventral hippocampus, dorso-medial thalamus, and amygdala. Between scans 2 and 3, animals were submitted to diverse behavioral tasks. Stainings were used to analyze tissue alterations. Twenty-four different animals received pilocarpine to evaluate the latency and severity of the status epilepticus 2 weeks after surgery. Additionally, eight different animals were only used to evaluate the neuronal damage inflicted on the MS 1 week after the molecular surgery. Progressive changes in DTI parameters in both white and gray matter structures of the four evaluated groups were observed. Behaviorally, the GAT1-saporin injection impacted spatial memory formation, while 192-IgG-saporin triggered anxiety-like behaviors. Histologically, the GABAergic toxin also induced aberrant mossy fiber sprouting, tissue damage, and neuronal death. Regarding the pilocarpine-induced status epilepticus, this agent provoked an increased mortality rate. Selective septo-hippocampal modulation impacts the integrity of limbic regions crucial for certain behavioral skills and could represent a precursor for epilepsy development.
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Affiliation(s)
- Hiram Luna-Munguia
- Departamento de Neurobiologia Conductual y Cognitiva, Instituto de Neurobiologia, Universidad Nacional Autonoma de Mexico, Campus UNAM-Juriquilla, 76230, Queretaro, Mexico.
| | - Deisy Gasca-Martinez
- Departamento de Neurobiologia Conductual y Cognitiva, Instituto de Neurobiologia, Universidad Nacional Autonoma de Mexico, Campus UNAM-Juriquilla, 76230, Queretaro, Mexico
- Unidad de Analisis Conductual, Instituto de Neurobiologia, Universidad Nacional Autonoma de Mexico, Campus UNAM-Juriquilla, 76230, Queretaro, Mexico
| | - Alejandra Garay-Cortes
- Departamento de Neurobiologia Conductual y Cognitiva, Instituto de Neurobiologia, Universidad Nacional Autonoma de Mexico, Campus UNAM-Juriquilla, 76230, Queretaro, Mexico
| | - Daniela Coutiño
- Departamento de Neurobiologia Conductual y Cognitiva, Instituto de Neurobiologia, Universidad Nacional Autonoma de Mexico, Campus UNAM-Juriquilla, 76230, Queretaro, Mexico
| | - Mirelta Regalado
- Departamento de Neurobiologia Conductual y Cognitiva, Instituto de Neurobiologia, Universidad Nacional Autonoma de Mexico, Campus UNAM-Juriquilla, 76230, Queretaro, Mexico
| | - Ericka de Los Rios
- Departamento de Neurobiologia Conductual y Cognitiva, Instituto de Neurobiologia, Universidad Nacional Autonoma de Mexico, Campus UNAM-Juriquilla, 76230, Queretaro, Mexico
- Unidad de Microscopia, Instituto de Neurobiologia, Universidad Nacional Autonoma de Mexico, Campus UNAM-Juriquilla, 76230, Queretaro, Mexico
| | - Paulina Villaseñor
- Departamento de Neurobiologia Conductual y Cognitiva, Instituto de Neurobiologia, Universidad Nacional Autonoma de Mexico, Campus UNAM-Juriquilla, 76230, Queretaro, Mexico
| | - Fernando Hidalgo-Flores
- Departamento de Neurobiologia Conductual y Cognitiva, Instituto de Neurobiologia, Universidad Nacional Autonoma de Mexico, Campus UNAM-Juriquilla, 76230, Queretaro, Mexico
| | - Karen Flores-Guapo
- Departamento de Neurobiologia Conductual y Cognitiva, Instituto de Neurobiologia, Universidad Nacional Autonoma de Mexico, Campus UNAM-Juriquilla, 76230, Queretaro, Mexico
| | - Brandon Yair Benito
- Departamento de Neurobiologia Conductual y Cognitiva, Instituto de Neurobiologia, Universidad Nacional Autonoma de Mexico, Campus UNAM-Juriquilla, 76230, Queretaro, Mexico
| | - Luis Concha
- Departamento de Neurobiologia Conductual y Cognitiva, Instituto de Neurobiologia, Universidad Nacional Autonoma de Mexico, Campus UNAM-Juriquilla, 76230, Queretaro, Mexico
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Smith J, Richerson G, Kouchi H, Duprat F, Mantegazza M, Bezin L, Rheims S. Are we there yet? A critical evaluation of sudden and unexpected death in epilepsy models. Epilepsia 2024; 65:9-25. [PMID: 37914406 DOI: 10.1111/epi.17812] [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: 08/04/2023] [Revised: 10/11/2023] [Accepted: 10/31/2023] [Indexed: 11/03/2023]
Abstract
Although animal models have helped to elaborate meaningful hypotheses about the pathophysiology of sudden and unexpected death in epilepsy (SUDEP), specific prevention strategies are still lacking, potentially reflecting the limitations of these models and the intrinsic difficulties of investigating SUDEP. The interpretation of preclinical data and their translation to diagnostic and therapeutic developments in patients thus require a high level of confidence in their relevance to model the human situation. Preclinical models of SUDEP are heterogeneous and include rodent and nonrodent species. A critical aspect is whether the animals have isolated seizures exclusively induced by a specific trigger, such as models where seizures are elicited by electrical stimulation, pharmacological intervention, or DBA mouse strains, or whether they suffer from epilepsy with spontaneous seizures, with or without spontaneous SUDEP, either of nongenetic epilepsy etiology or from genetically based developmental and epileptic encephalopathies. All these models have advantages and potential disadvantages, but it is important to be aware of these limitations to interpret data appropriately in a translational perspective. The majority of models with spontaneous seizures are of a genetic basis, whereas SUDEP cases with a genetic basis represent only a small proportion of the total number. In almost all models, cardiorespiratory arrest occurs during the course of the seizure, contrary to that in patients observed at the time of death, potentially raising the issue of whether we are studying models of SUDEP or models of periseizure death. However, some of these limitations are impossible to avoid and can in part be dependent on specific features of SUDEP, which may be difficult to model. Several preclinical tools are available to address certain gaps in SUDEP pathophysiology, which can be used to further validate current preclinical models.
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Affiliation(s)
- Jonathon Smith
- Lyon Neuroscience Research Center (CRNL, INSERM U1028/CNRS UMR 5292, Lyon 1 University), Lyon, France
| | - George Richerson
- Department of Neurology, University of Iowa, Iowa City, Iowa, USA
| | - Hayet Kouchi
- Lyon Neuroscience Research Center (CRNL, INSERM U1028/CNRS UMR 5292, Lyon 1 University), Lyon, France
| | - Fabrice Duprat
- University Cote d'Azur, Valbonne-Sophia Antipolis, France
- CNRS UMR 7275, Institute of Molecular and Cellular Pharmacology, Valbonne-Sophia Antipolis, France
- Inserm, Valbonne-Sophia Antipolis, France
| | - Massimo Mantegazza
- University Cote d'Azur, Valbonne-Sophia Antipolis, France
- CNRS UMR 7275, Institute of Molecular and Cellular Pharmacology, Valbonne-Sophia Antipolis, France
- Inserm, Valbonne-Sophia Antipolis, France
| | - Laurent Bezin
- Lyon Neuroscience Research Center (CRNL, INSERM U1028/CNRS UMR 5292, Lyon 1 University), Lyon, France
| | - Sylvain Rheims
- Lyon Neuroscience Research Center (CRNL, INSERM U1028/CNRS UMR 5292, Lyon 1 University), Lyon, France
- Department of Functional Neurology and Epileptology, Hospices Civils de Lyon and Lyon 1 University, Lyon, France
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Bhandare AM, Dale N. Neural correlate of reduced respiratory chemosensitivity during chronic epilepsy. Front Cell Neurosci 2023; 17:1288600. [PMID: 38193031 PMCID: PMC10773801 DOI: 10.3389/fncel.2023.1288600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Accepted: 11/27/2023] [Indexed: 01/10/2024] Open
Abstract
While central autonomic, cardiac, and/or respiratory dysfunction underlies sudden unexpected death in epilepsy (SUDEP), the specific neural mechanisms that lead to SUDEP remain to be determined. In this study, we took advantage of single-cell neuronal Ca2+ imaging and intrahippocampal kainic acid (KA)-induced chronic epilepsy in mice to investigate progressive changes in key cardiorespiratory brainstem circuits during chronic epilepsy. Weeks after induction of status epilepticus (SE), when mice were experiencing recurrent spontaneous seizures (chronic epilepsy), we observed that the adaptive ventilatory responses to hypercapnia were reduced for 5 weeks after SE induction with its partial recovery at week 7. These changes were paralleled by alterations in the chemosensory responses of neurons in the retrotrapezoid nucleus (RTN). Neurons that displayed adapting responses to hypercapnia were less prevalent and exhibited smaller responses over weeks 3-5, whereas neurons that displayed graded responses to hypercapnia became more prevalent by week 7. Over the same period, chemosensory responses of the presympathetic rostral ventrolateral medullary (RVLM) neurons showed no change. Mice with chronic epilepsy showed enhanced sensitivity to seizures, which invade the RTN and possibly put the chemosensory circuits at further risk of impairment. Our findings establish a dysfunctional breathing phenotype with its RTN neuronal correlate in mice with chronic epilepsy and suggest that the assessment of respiratory chemosensitivity may have the potential for identifying people at risk of SUDEP.
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Affiliation(s)
- Amol M. Bhandare
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
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Rawat K, Gautam V, Sandhu A, Bhatia A, Saha L. Differential Regulation of Wnt/β-catenin Signaling in Acute and Chronic Epilepsy in Repeated Low Dose Lithium-Pilocarpine Rat Model of Status Epilepticus. Neuroscience 2023; 535:36-49. [PMID: 37913863 DOI: 10.1016/j.neuroscience.2023.10.019] [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: 05/26/2023] [Revised: 10/19/2023] [Accepted: 10/23/2023] [Indexed: 11/03/2023]
Abstract
Epilepsy is a chronic neurological complication characterized by unprovoked seizure episodes due to the imbalance between excitatory and inhibitory neurons. The epileptogenesis process has been reported to be involved in chronic epilepsy however, the mechanism underlying epileptogenesis remains unclear. Recent studies have shown the possible involvement of Wnt/β-catenin signaling in the neurogenesis and neuronal reorganization in epileptogenesis. In this study, we used repeated low dose lithium-pilocarpine model of status epilepsy (SE) to study the involvement of Wnt/β-catenin signaling at acute and chronic stages post SE induction. The acute study ranged from day 0 to day 28 post SE induction and the chronic study ranged from day 0 to day 56 post SE induction. Several neurobehavioral parameters and seizure score and seizure frequency was analysed until the end of the study. The proteins involved in the regulation of Wnt/β-catenin signaling and downstream cascading were analysed using western blot and quantitative real-time PCR analysis. The Wnt/β-catenin pathway was found inactive in acute SE, while the same was found activated at the chronic stage. Our findings suggest that the activated Wnt/β-catenin signaling in chronic epilepsy might be the possible mechanism underlying epileptogenesis as indicated by increased neuronal count, increased synaptic density, astrogliosis and apoptosis in chronic epilepsy. These findings can help target the Wnt/β-catenin pathway differentially depending upon the type of epilepsy. The acute stage characterized by SE can be improved by targeting GSK-3β levels and the chronic stage characterized by temporal lobe epilepsy can be improved by targeting β-catenin and disheveled proteins.
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Affiliation(s)
- Kajal Rawat
- Department of Pharmacology, Research Block B, Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh 160012, India
| | - Vipasha Gautam
- Department of Pharmacology, Research Block B, Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh 160012, India
| | - Arushi Sandhu
- Department of Pharmacology, Research Block B, Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh 160012, India
| | - Alka Bhatia
- Department of Experimental Medicine and Biotechnology, Research Block B, Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh 160012, India
| | - Lekha Saha
- Department of Pharmacology, Research Block B, Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh 160012, India.
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Bernard C, Frauscher B, Gelinas J, Timofeev I. Sleep, oscillations, and epilepsy. Epilepsia 2023; 64 Suppl 3:S3-S12. [PMID: 37226640 PMCID: PMC10674035 DOI: 10.1111/epi.17664] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 04/27/2023] [Accepted: 05/23/2023] [Indexed: 05/26/2023]
Abstract
Sleep and wake are defined through physiological and behavioral criteria and can be typically separated into non-rapid eye movement (NREM) sleep stages N1, N2, and N3, rapid eye movement (REM) sleep, and wake. Sleep and wake states are not homogenous in time. Their properties vary during the night and day cycle. Given that brain activity changes as a function of NREM, REM, and wake during the night and day cycle, are seizures more likely to occur during NREM, REM, or wake at a specific time? More generally, what is the relationship between sleep-wake cycles and epilepsy? We will review specific examples from clinical data and results from experimental models, focusing on the diversity and heterogeneity of these relationships. We will use a top-down approach, starting with the general architecture of sleep, followed by oscillatory activities, and ending with ionic correlates selected for illustrative purposes, with respect to seizures and interictal spikes. The picture that emerges is that of complexity; sleep disruption and pathological epileptic activities emerge from reorganized circuits. That different circuit alterations can occur across patients and models may explain why sleep alterations and the timing of seizures during the sleep-wake cycle are patient-specific.
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Affiliation(s)
| | - Birgit Frauscher
- Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada
| | - Jennifer Gelinas
- Institute for Genomic Medicine, Columbia University Medical Center, New York, NY, USA
- Department of Neurology, Columbia University Medical Center, New York, NY, USA
| | - Igor Timofeev
- Faculté de Médecine, Département de Psychiatrie et de Neurosciences, Centre de Recherche CERVO, Université Laval, Québec, QC G1J2G3, Canada
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Schartz ND, Aroor A, Li Y, Pinzón-Hoyos N, Brewster AL. Mice deficient in complement C3 are protected against recognition memory deficits and astrogliosis induced by status epilepticus. Front Mol Neurosci 2023; 16:1265944. [PMID: 38035266 PMCID: PMC10682718 DOI: 10.3389/fnmol.2023.1265944] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 10/23/2023] [Indexed: 12/02/2023] Open
Abstract
Introduction Status epilepticus (SE) can significantly increase the risk of temporal lobe epilepsy (TLE) and cognitive comorbidities. A potential candidate mechanism underlying memory defects in epilepsy may be the immune complement system. The complement cascade, part of the innate immune system, modulates inflammatory and phagocytosis signaling, and has been shown to contribute to learning and memory dysfunctions in neurodegenerative disorders. We previously reported that complement C3 is elevated in brain biopsies from human drug-resistant epilepsy and in experimental rodent models. We also found that SE-induced increases in hippocampal C3 levels paralleled the development of hippocampal-dependent spatial learning and memory deficits in rats. Thus, we hypothesized that SE-induced C3 activation contributes to this pathophysiology in a mouse model of SE and acquired TLE. Methods In this study C3 knockout (KO) and wild type (WT) mice were subjected to one hour of pilocarpine-induced SE or sham conditions (control; C). Following a latent period of two weeks, recognition memory was assessed utilizing the novel object recognition (NOR) test. Western blotting was utilized to determine the protein levels of C3 in hippocampal lysates. In addition, we assessed the protein levels and distribution of the astrocyte marker glial fibrillary acidic protein (GFAP). Results In the NOR test, control WT + C or C3 KO + C mice spent significantly more time exploring the novel object compared to the familiar object. In contrast, WT+SE mice did not show preference for either object, indicating a memory defect. This deficit was prevented in C3 KO + SE mice, which performed similarly to controls. In addition, we found that SE triggered significant increases in the protein levels of GFAP in hippocampi of WT mice but not in C3 KO mice. Discussion These findings suggest that ablation of C3 prevents SE-induced recognition memory deficits and that a C3-astrocyte interplay may play a role. Therefore, it is possible that enhanced C3 signaling contributes to SE-associated cognitive decline during epileptogenesis and may serve as a potential therapeutic target for treating cognitive comorbidities in acquired TLE.
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Affiliation(s)
- Nicole D. Schartz
- Department of Psychological Sciences, Purdue University, West Lafayette, IN, United States
- Department of Geriatrics, University of Arkansas for Medical Sciences, Little Rock, AR, United States
| | - Alisha Aroor
- Department of Psychological Sciences, Purdue University, West Lafayette, IN, United States
| | - Yibo Li
- Department of Biological Sciences, Southern Methodist University, Dallas, TX, United States
| | - Nicole Pinzón-Hoyos
- Department of Biological Sciences, Southern Methodist University, Dallas, TX, United States
| | - Amy L. Brewster
- Department of Biological Sciences, Southern Methodist University, Dallas, TX, United States
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11
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Whitebirch AC, Santoro B, Barnett A, Lisgaras CP, Scharfman HE, Siegelbaum SA. Reduced Cholecystokinin-Expressing Interneuron Input Contributes to Disinhibition of the Hippocampal CA2 Region in a Mouse Model of Temporal Lobe Epilepsy. J Neurosci 2023; 43:6930-6949. [PMID: 37643861 PMCID: PMC10573827 DOI: 10.1523/jneurosci.2091-22.2023] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 08/04/2023] [Accepted: 08/15/2023] [Indexed: 08/31/2023] Open
Abstract
A significant proportion of temporal lobe epilepsy (TLE) patients experience drug-resistant seizures associated with mesial temporal sclerosis, in which there is extensive cell loss in the hippocampal CA1 and CA3 subfields, with a relative sparing of dentate gyrus granule cells and CA2 pyramidal neurons (PNs). A role for CA2 in seizure generation was suggested based on findings of a reduction in CA2 synaptic inhibition (Williamson and Spencer, 1994) and the presence of interictal-like spike activity in CA2 in resected hippocampal tissue from TLE patients (Wittner et al., 2009). We recently found that in the pilocarpine-induced status epilepticus (PILO-SE) mouse model of TLE there was an increase in CA2 intrinsic excitability associated with a loss of CA2 synaptic inhibition. Furthermore, chemogenetic silencing of CA2 significantly reduced seizure frequency, consistent with a role of CA2 in promoting seizure generation and/or propagation (Whitebirch et al., 2022). In the present study, we explored the cellular basis of this inhibitory deficit using immunohistochemical and electrophysiological approaches in PILO-SE male and female mice. We report a widespread decrease in the density of pro-cholecystokinin-immunopositive (CCK+) interneurons and a functional impairment of CCK+ interneuron-mediated inhibition of CA2 PNs. We also found a disruption in the perisomatic perineuronal net in the CA2 stratum pyramidale. Such pathologic alterations may contribute to an enhanced excitation of CA2 PNs and CA2-dependent seizure activity in the PILO-SE mouse model.SIGNIFICANCE STATEMENT Impaired synaptic inhibition in hippocampal circuits has been identified as a key feature that contributes to the emergence and propagation of seizure activity in human patients and animal models of temporal lobe epilepsy (TLE). Among the hippocampal subfields, the CA2 region is particularly resilient to seizure-associated neurodegeneration and has been suggested to play a key role in seizure activity in TLE. Here we report that perisomatic inhibition of CA2 pyramidal neurons mediated by cholecystokinin-expressing interneurons is selectively reduced in acute hippocampal slices from epileptic mice. Parvalbumin-expressing interneurons, in contrast, appear relatively conserved in epileptic mice. These findings advance our understanding of the cellular mechanisms underlying inhibitory disruption in hippocampal circuits in a mouse model of spontaneous recurring seizures.
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Affiliation(s)
- Alexander C Whitebirch
- Departments of Neuroscience and Pharmacology, Kavli Institute for Brain Science, Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University Irving Medical Center, New York, New York 10027
| | - Bina Santoro
- Departments of Neuroscience and Pharmacology, Kavli Institute for Brain Science, Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University Irving Medical Center, New York, New York 10027
| | - Anastasia Barnett
- Departments of Neuroscience and Pharmacology, Kavli Institute for Brain Science, Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University Irving Medical Center, New York, New York 10027
| | - Christos Panagiotis Lisgaras
- Department of Child & Adolescent Psychiatry, New York University Langone Health, New York, New York 10016
- Department of Neuroscience & Physiology, New York University Langone Health, New York, New York 10016
- Department of Psychiatry, New York University Langone Health, New York, New York 10016
- The Nathan S. Kline Institute for Psychiatric Research, Orangeburg, New York 10962
| | - Helen E Scharfman
- Department of Child & Adolescent Psychiatry, New York University Langone Health, New York, New York 10016
- Department of Neuroscience & Physiology, New York University Langone Health, New York, New York 10016
- Department of Psychiatry, New York University Langone Health, New York, New York 10016
- The Nathan S. Kline Institute for Psychiatric Research, Orangeburg, New York 10962
| | - Steven A Siegelbaum
- Departments of Neuroscience and Pharmacology, Kavli Institute for Brain Science, Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University Irving Medical Center, New York, New York 10027
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12
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Guignet M, Campbell A, Vuong J, Whittington D, White HS. Perampanel's forgiveness factor in a variable medication adherence paradigm in a rat model of chronic epilepsy. J Transl Med 2023; 21:642. [PMID: 37730661 PMCID: PMC10510183 DOI: 10.1186/s12967-023-04490-z] [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: 04/14/2023] [Accepted: 08/30/2023] [Indexed: 09/22/2023] Open
Abstract
BACKGROUND Poor medication adherence contributes to increased morbidity and mortality in patients with epilepsy and may be under-addressed in clinical practice. Ethical concerns make it impossible to study the impact of medication nonadherence in clinical trials, but our previous work emphasizes the importance of using preclinical approaches to address these questions. With over 30 clinically available antiseizure medicines (ASM's), it remains an important question to understand the relationship between poor adherence and seizure incidence across mechanistically distinct ASM's, including the broad-spectrum ASM, perampanel (PER). METHODS We formulated PER into chow pellets to deliver to rats in a 100% fully adherent or 50% variable nonadherent paradigm via our novel automated medication-in-food delivery system. Chronic oral dosing was initiated in male rats with chronic epilepsy while monitoring 24/7 for videoEEG evidence of seizures during a 4-week placebo baseline and 4-week treatment phase. PER concentrations were monitored in plasma at 1-week intervals and correlated with degree of seizure control. The relationship between missed doses and extended patterns of nonadherence were correlated with breakthrough seizures. RESULTS Fully adherent rats demonstrated a median reduction in seizure frequency of 50%, whereas nonadherent rats had a median increase of 54%. Plasma concentrations of PER were stable over the 4-week treatment period in both fully adherent and nonadherent groups, with levels being twice as high in fully adherent animals. There was no correlation between a single missed dose or series of missed doses and the incidence of breakthrough seizures. However, those animals in the nonadherent group that received PER for every meal during a 24-h period had a reduced likelihood of seizure incidence. CONCLUSIONS If our preclinical data is supported in the clinic, PER's favorable pharmacokinetic profile in humans, combined with a lowered risk of breakthrough seizures suggests that it may provide a certain forgiveness factor if a dose is missed within a 24-h window.
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Affiliation(s)
- Michelle Guignet
- School of Pharmacy Seattle, University of Washington, Seattle, WA, USA.
| | - Amanda Campbell
- Center for Epilepsy Drug Discovery, Department of Pharmacy, School of Pharmacy, University of Washington, Health Sciences Building F563, 1959 NE Pacific Street, Box 357630, Seattle, WA, 98195-7630, USA
| | - Jonathan Vuong
- Center for Epilepsy Drug Discovery, Department of Pharmacy, School of Pharmacy, University of Washington, Health Sciences Building F563, 1959 NE Pacific Street, Box 357630, Seattle, WA, 98195-7630, USA
| | - Dale Whittington
- Department of Medicinal Chemistry, School of Pharmacy, University of Washington, Seattle, WA, 98159, USA
| | - H Steve White
- Center for Epilepsy Drug Discovery, Department of Pharmacy, School of Pharmacy, University of Washington, Health Sciences Building F563, 1959 NE Pacific Street, Box 357630, Seattle, WA, 98195-7630, USA
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13
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Che Has AT. The applications of the pilocarpine animal model of status epilepticus: 40 years of progress (1983-2023). Behav Brain Res 2023; 452:114551. [PMID: 37348654 DOI: 10.1016/j.bbr.2023.114551] [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: 04/30/2023] [Revised: 06/02/2023] [Accepted: 06/18/2023] [Indexed: 06/24/2023]
Abstract
Status epilepticus is a neurological disorder that can result in various neuropathological conditions and presentations. Various studies involving animal models have been accomplished to understand and replicating its prominent manifestations including characteristics of related clinical cases. Up to these days, there are variety of methods and techniques to be utilized in inducing this disorder that can be chemically or electrically applied which depending on the experimental designs and targets of the studies. In particular, the chemically induced pilocarpine animal model of status epilepticus is a reliable choice which has evolved for 40 years from its initial discovery back in 1983. Although the development of the model can be considered as a remarkable breakthrough in understanding status epilepticus, several aspects of the model have been improved, throughout the years. Among the major issues in developing this model are the morbidity and mortality rates during induction process. Several modifications have been introduced in the process by different studies to tackle the related problems including application of dose fractionation, adaptation of pilocarpine to lithium-pilocarpine model and utilization of various drugs. Despite all challenges and drawbacks, this model has proven its pertinent and relevance with improvements that have been adapted since it was introduced 40 years ago. In this review, we emphasize on the evolution of this animal model from the beginning until now (1983 - 2023) and the related issues that have made this model still a popular choice in status epilepticus studies.
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Affiliation(s)
- Ahmad Tarmizi Che Has
- Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia Health Campus Kubang Kerian, 16150, Kota Bharu, Kelantan, Malaysia.
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14
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Bosco F, Guarnieri L, Leo A, Tallarico M, Gallelli L, Rania V, Citraro R, De Sarro G. Audiogenic epileptic DBA/2 mice strain as a model of genetic reflex seizures and SUDEP. Front Neurol 2023; 14:1223074. [PMID: 37681009 PMCID: PMC10481168 DOI: 10.3389/fneur.2023.1223074] [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: 05/15/2023] [Accepted: 07/14/2023] [Indexed: 09/09/2023] Open
Abstract
Epilepsy is a chronic neurological disease characterized by abnormal brain activity, which results in repeated spontaneous seizures. Sudden unexpected death in epilepsy (SUDEP) is the leading cause of seizure-related premature death, particularly in drug-resistant epilepsy patients. The etiology of SUDEP is a structural injury to the brain that is not fully understood, but it is frequently associated with poorly controlled and repeated generalized tonic-clonic seizures (GTCSs) that cause cardiorespiratory and autonomic dysfunctions, indicating the involvement of the brainstem. Both respiratory and cardiac abnormalities have been observed in SUDEP, but not much progress has been made in their prevention. Owing to the complexity of SUDEP, experimental animal models have been used to investigate cardiac and/or respiratory dysregulation due to or associated with epileptic seizures that may contribute to death in humans. Numerous rodent models, especially mouse models, have been developed to better understand epilepsy and SUDEP physiopathology. This review synthesizes the current knowledge about dilute brown agouti coat color (DBA/2) mice as a possible SUDEP model because respiratory arrest (RA) and sudden death induced by audiogenic generalized seizures (AGSs) have been observed in these animals. Respiratory/cardiac dysfunction, brainstem arousal system dysfunction, and alteration of the neurotransmitter systems, which are observed in human SUDEP, have also been observed in these mice. In particular, serotonin (5-HT) alteration and adenosine neurotransmission appear to contribute to not only the pathophysiological mechanisms of medication but also seizure-related respiratory dysfunctions in this animal model. These neurotransmitter systems could be the relevant targets for medication development for chronic epilepsy and SUDEP prevention. We reviewed data on AGSs in DBA/2 mice and the relevance of this model of generalized tonic-clonic epilepsy to human SUDEP. Furthermore, the advantages of using this strain prone to AGSs for the identification of possible new therapeutic targets and treatment options have also been assessed.
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Affiliation(s)
- Francesca Bosco
- Section of Pharmacology, Science of Health Department, School of Medicine, University “Magna Graecia” of Catanzaro, Catanzaro, Italy
| | - Lorenza Guarnieri
- Section of Pharmacology, Science of Health Department, School of Medicine, University “Magna Graecia” of Catanzaro, Catanzaro, Italy
| | - Antonio Leo
- Section of Pharmacology, Science of Health Department, School of Medicine, University “Magna Graecia” of Catanzaro, Catanzaro, Italy
- Research Center FAS@UMG, Department of Health Science, University “Magna Graecia” of Catanzaro, Catanzaro, Italy
| | - Martina Tallarico
- Section of Pharmacology, Science of Health Department, School of Medicine, University “Magna Graecia” of Catanzaro, Catanzaro, Italy
| | - Luca Gallelli
- Section of Pharmacology, Science of Health Department, School of Medicine, University “Magna Graecia” of Catanzaro, Catanzaro, Italy
- Research Center FAS@UMG, Department of Health Science, University “Magna Graecia” of Catanzaro, Catanzaro, Italy
| | - Vincenzo Rania
- Section of Pharmacology, Science of Health Department, School of Medicine, University “Magna Graecia” of Catanzaro, Catanzaro, Italy
| | - Rita Citraro
- Section of Pharmacology, Science of Health Department, School of Medicine, University “Magna Graecia” of Catanzaro, Catanzaro, Italy
- Research Center FAS@UMG, Department of Health Science, University “Magna Graecia” of Catanzaro, Catanzaro, Italy
| | - Giovambattista De Sarro
- Section of Pharmacology, Science of Health Department, School of Medicine, University “Magna Graecia” of Catanzaro, Catanzaro, Italy
- Research Center FAS@UMG, Department of Health Science, University “Magna Graecia” of Catanzaro, Catanzaro, Italy
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15
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Wu J, Liu P, Geng C, Liu C, Li J, Zhu Q, Li A. Principal neurons in the olfactory cortex mediate bidirectional modulation of seizures. J Physiol 2023; 601:3557-3584. [PMID: 37384845 DOI: 10.1113/jp284731] [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: 03/22/2023] [Accepted: 06/15/2023] [Indexed: 07/01/2023] Open
Abstract
Although the piriform cortex (PC) has been previously implicated as a critical node for seizure generation and propagation, the underlying neural mechanism has remained unclear. Here, we found increased excitability in PC neurons during amygdala kindling acquisition. Optogenetic or chemogenetic activation of PC pyramidal neurons promoted kindling progression, whereas inhibition of these neurons retarded seizure activities induced by electrical kindling in the amygdala. Furthermore, chemogenetic inhibition of PC pyramidal neurons alleviated the severity of kainic acid-induced acute seizures. These results demonstrate that PC pyramidal neurons bidirectionally modulate seizures in temporal lobe epilepsy, providing evidence for the efficacy of PC pyramidal neurons as a potential therapeutic target for epileptogenesis. KEY POINTS: While the piriform cortex (PC) is an important olfactory centre critically involved in olfactory processing and plays a crucial role in epilepsy due to its close connection with the limbic system, how the PC regulates epileptogenesis is largely unknown. In this study, we evaluated the neuronal activity and the role of pyramidal neurons in the PC in the mouse amygdala kindling model of epilepsy. PC pyramidal neurons are hyperexcited during epileptogenesis. Optogenetic and chemogenetic activation of PC pyramidal neurons significantly promoted seizures in the amygdala kindling model, whereas selective inhibition of these neurons produced an anti-epileptic effect for both electrical kindling and kainic acid-induced acute seizures. The results of the present study indicate that PC pyramidal neurons bidirectionally modulate seizure activity.
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Affiliation(s)
- Jing Wu
- Jiangsu Key Laboratory of Brain Disease and Bioinformation, Research Center for Biochemistry and Molecular Biology, Xuzhou Medical University, Xuzhou, China
| | - Penglai Liu
- Jiangsu Key Laboratory of Brain Disease and Bioinformation, Research Center for Biochemistry and Molecular Biology, Xuzhou Medical University, Xuzhou, China
| | - Chi Geng
- Jiangsu Key Laboratory of Brain Disease and Bioinformation, Research Center for Biochemistry and Molecular Biology, Xuzhou Medical University, Xuzhou, China
| | - Changyu Liu
- Jiangsu Key Laboratory of Brain Disease and Bioinformation, Research Center for Biochemistry and Molecular Biology, Xuzhou Medical University, Xuzhou, China
| | - Jiaxin Li
- Jiangsu Key Laboratory of Brain Disease and Bioinformation, Research Center for Biochemistry and Molecular Biology, Xuzhou Medical University, Xuzhou, China
| | - Qiuju Zhu
- Jiangsu Key Laboratory of Brain Disease and Bioinformation, Research Center for Biochemistry and Molecular Biology, Xuzhou Medical University, Xuzhou, China
| | - Anan Li
- Jiangsu Key Laboratory of Brain Disease and Bioinformation, Research Center for Biochemistry and Molecular Biology, Xuzhou Medical University, Xuzhou, China
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16
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Patel DC, Swift N, Tewari BP, Browning JL, Prim C, Chaunsali L, Kimbrough I, Olsen ML, Sontheimer H. Infection-induced epilepsy is caused by increased expression of chondroitin sulfate proteoglycans in hippocampus and amygdala. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.16.541066. [PMID: 37292901 PMCID: PMC10245664 DOI: 10.1101/2023.05.16.541066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Alterations in the extracellular matrix (ECM) are common in epilepsy, yet whether they are cause or consequence of disease is unknow. Using Theiler's virus infection model of acquired epilepsy we find de novo expression of chondroitin sulfate proteoglycans (CSPGs), a major ECM component, in dentate gyrus (DG) and amygdala exclusively in mice with seizures. Preventing synthesis of CSPGs specifically in DG and amygdala by deletion of major CSPG aggrecan reduced seizure burden. Patch-clamp recordings from dentate granule cells (DGCs) revealed enhanced intrinsic and synaptic excitability in seizing mice that was normalized by aggrecan deletion. In situ experiments suggest that DGCs hyperexcitability results from negatively charged CSPGs increasing stationary cations (K+, Ca2+) on the membrane thereby depolarizing neurons, increasing their intrinsic and synaptic excitability. We show similar changes in CSPGs in pilocarpine-induced epilepsy suggesting enhanced CSPGs in the DG and amygdala may be a common ictogenic factor and novel therapeutic potential.
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Affiliation(s)
- Dipan C Patel
- Department of Neuroscience, School of Medicine, University of Virginia, Charlottesville, VA 22903, USA
| | - Nathaniel Swift
- Department of Internal Medicine, Gerontology and Geriatric Medicine, School of Medicine, Wake Forest University, Winston-Salem, NC 27157, USA
| | - Bhanu P Tewari
- Department of Neuroscience, School of Medicine, University of Virginia, Charlottesville, VA 22903, USA
| | - Jack L Browning
- School of Neuroscience, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
| | - Courtney Prim
- Department of Neuroscience, School of Medicine, University of Virginia, Charlottesville, VA 22903, USA
| | - Lata Chaunsali
- Department of Neuroscience, School of Medicine, University of Virginia, Charlottesville, VA 22903, USA
| | - Ian Kimbrough
- Department of Neuroscience, School of Medicine, University of Virginia, Charlottesville, VA 22903, USA
| | - Michelle L Olsen
- School of Neuroscience, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
| | - Harald Sontheimer
- Department of Neuroscience, School of Medicine, University of Virginia, Charlottesville, VA 22903, USA
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17
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Löscher W, White HS. Animal Models of Drug-Resistant Epilepsy as Tools for Deciphering the Cellular and Molecular Mechanisms of Pharmacoresistance and Discovering More Effective Treatments. Cells 2023; 12:cells12091233. [PMID: 37174633 PMCID: PMC10177106 DOI: 10.3390/cells12091233] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 02/28/2023] [Accepted: 04/18/2023] [Indexed: 05/15/2023] Open
Abstract
In the last 30 years, over 20 new anti-seizure medicines (ASMs) have been introduced into the market for the treatment of epilepsy using well-established preclinical seizure and epilepsy models. Despite this success, approximately 20-30% of patients with epilepsy have drug-resistant epilepsy (DRE). The current approach to ASM discovery for DRE relies largely on drug testing in various preclinical model systems that display varying degrees of ASM drug resistance. In recent years, attempts have been made to include more etiologically relevant models in the preclinical evaluation of a new investigational drug. Such models have played an important role in advancing a greater understanding of DRE at a mechanistic level and for hypothesis testing as new experimental evidence becomes available. This review provides a critical discussion of the pharmacology of models of adult focal epilepsy that allow for the selection of ASM responders and nonresponders and those models that display a pharmacoresistance per se to two or more ASMs. In addition, the pharmacology of animal models of major genetic epilepsies is discussed. Importantly, in addition to testing chemical compounds, several of the models discussed here can be used to evaluate other potential therapies for epilepsy such as neurostimulation, dietary treatments, gene therapy, or cell transplantation. This review also discusses the challenges associated with identifying novel therapies in the absence of a greater understanding of the mechanisms that contribute to DRE. Finally, this review discusses the lessons learned from the profile of the recently approved highly efficacious and broad-spectrum ASM cenobamate.
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Affiliation(s)
- Wolfgang Löscher
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine, Bünteweg 17, 30559 Hannover, Germany
- Center for Systems Neuroscience, 30559 Hannover, Germany
| | - H Steve White
- Department of Pharmacy, School of Pharmacy, University of Washington, Seattle, WA 98195, USA
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18
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Cumbres-Vargas IM, Zamudio SR, Pichardo-Macías LA, Ramírez-San Juan E. Thalidomide Attenuates Epileptogenesis and Seizures by Decreasing Brain Inflammation in Lithium Pilocarpine Rat Model. Int J Mol Sci 2023; 24:ijms24076488. [PMID: 37047461 PMCID: PMC10094940 DOI: 10.3390/ijms24076488] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 03/23/2023] [Accepted: 03/28/2023] [Indexed: 04/14/2023] Open
Abstract
Thalidomide (TAL) has shown potential therapeutic effects in neurological diseases like epilepsy. Both clinical and preclinical studies show that TAL may act as an antiepileptic drug and as a possible treatment against disease development. However, the evidence for these effects is limited. Therefore, the antiepileptogenic and anti-inflammatory effects of TAL were evaluated herein. Sprague Dawley male rats were randomly allocated to one of five groups (n = 18 per group): control (C); status epilepticus (SE); SE-TAL (25 mg/kg); SE-TAL (50 mg/kg); and SE-topiramate (TOP; 60mg/kg). The lithium-pilocarpine model was used, and one day after SE induction the rats received pharmacological treatment for one week. The brain was obtained, and the hippocampus was micro-dissected 8, 18, and 28 days after SE. TNF-α, IL-6, and IL-1β concentrations were quantified. TOP and TAL (50 mg/kg) increased the latency to the first of many spontaneous recurrent seizures (SRS) and decreased SRS frequency, as well as decreasing TNF-α and IL-1β concentrations in the hippocampus. In conclusion, the results showed that both TAL (50 mg/kg) and TOP have anti-ictogenic and antiepileptogenic effects, possibly by decreasing neuroinflammation.
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Affiliation(s)
- Irán M Cumbres-Vargas
- Departamento de Fisiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City 07738, Mexico
| | - Sergio R Zamudio
- Departamento de Fisiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City 07738, Mexico
| | - Luz A Pichardo-Macías
- Departamento de Fisiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City 07738, Mexico
| | - Eduardo Ramírez-San Juan
- Departamento de Fisiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City 07738, Mexico
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19
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Avoli M, Chen LY, Di Cristo G, Librizzi L, Scalmani P, Shiri Z, Uva L, de Curtis M, Lévesque M. Ligand-gated mechanisms leading to ictogenesis in focal epileptic disorders. Neurobiol Dis 2023; 180:106097. [PMID: 36967064 DOI: 10.1016/j.nbd.2023.106097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 03/14/2023] [Accepted: 03/22/2023] [Indexed: 04/03/2023] Open
Abstract
We review here the neuronal mechanisms that cause seizures in focal epileptic disorders and, specifically, those involving limbic structures that are known to be implicated in human mesial temporal lobe epilepsy. In both epileptic patients and animal models, the initiation of focal seizures - which are most often characterized by a low-voltage fast onset EEG pattern - is presumably dependent on the synchronous firing of GABA-releasing interneurons that, by activating post-synaptic GABAA receptors, cause large increases in extracellular [K+] through the activation of the co-transporter KCC2. A similar mechanism may contribute to seizure maintenance; accordingly, inhibiting KCC2 activity transforms seizure activity into a continuous pattern of short-lasting epileptiform discharges. It has also been found that interactions between different areas of the limbic system modulate seizure occurrence by controlling extracellular [K+] homeostasis. In line with this view, low-frequency electrical or optogenetic activation of limbic networks restrain seizure generation, an effect that may also involve the activation of GABAB receptors and activity-dependent changes in epileptiform synchronization. Overall, these findings highlight the paradoxical role of GABAA signaling in both focal seizure generation and maintenance, emphasize the efficacy of low-frequency activation in abating seizures, and provide experimental evidence explaining the poor efficacy of antiepileptic drugs designed to augment GABAergic function in controlling seizures in focal epileptic disorders.
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Affiliation(s)
- Massimo Avoli
- Montreal Neurological Institute-Hospital, Departments of Neurology, Canada; Neurology & Neurosurgery and of Physiology, McGill University, Montreal H3A 2B4, Que, Canada.
| | - Li-Yuan Chen
- Montreal Neurological Institute-Hospital, Departments of Neurology, Canada
| | - Graziella Di Cristo
- Neurosciences Department, Université de Montréal, Montréal, Québec H3T 1N8, Canada; CHU Sainte-Justine Research Center, Montréal, Québec H3T 1C5, Canada
| | - Laura Librizzi
- Epilepsy Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milano, Italy
| | - Paolo Scalmani
- Epilepsy Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milano, Italy
| | - Zahra Shiri
- Montreal Neurological Institute-Hospital, Departments of Neurology, Canada
| | - Laura Uva
- Epilepsy Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milano, Italy
| | - Marco de Curtis
- Epilepsy Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milano, Italy
| | - Maxime Lévesque
- Montreal Neurological Institute-Hospital, Departments of Neurology, Canada
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20
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Lévesque M, Wang S, Macey-Dare ADB, Salami P, Avoli M. Evolution of interictal activity in models of mesial temporal lobe epilepsy. Neurobiol Dis 2023; 180:106065. [PMID: 36907521 DOI: 10.1016/j.nbd.2023.106065] [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: 01/23/2023] [Revised: 02/22/2023] [Accepted: 03/02/2023] [Indexed: 03/12/2023] Open
Abstract
Interictal activity and seizures are the hallmarks of focal epileptic disorders (which include mesial temporal lobe epilepsy, MTLE) in humans and in animal models. Interictal activity, which is recorded with cortical and intracerebral EEG recordings, comprises spikes, sharp waves and high-frequency oscillations, and has been used in clinical practice to identify the epileptic zone. However, its relation with seizures remains debated. Moreover, it is unclear whether specific EEG changes in interictal activity occur during the time preceding the appearance of spontaneous seizures. This period, which is termed "latent", has been studied in rodent models of MTLE in which spontaneous seizures start to occur following an initial insult (most often a status epilepticus induced by convulsive drugs such as kainic acid or pilocarpine) and may mirror epileptogenesis, i.e., the process leading the brain to develop an enduring predisposition to seizure generation. Here, we will address this topic by reviewing experimental studies performed in MTLE models. Specifically, we will review data highlighting the dynamic changes in interictal spiking activity and high-frequency oscillations occurring during the latent period, and how optogenetic stimulation of specific cell populations can modulate them in the pilocarpine model. These findings indicate that interictal activity: (i) is heterogeneous in its EEG patterns and thus, presumably, in its underlying neuronal mechanisms; and (ii) can pinpoint to the epileptogenic processes occurring in focal epileptic disorders in animal models and, perhaps, in epileptic patients.
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Affiliation(s)
- Maxime Lévesque
- Montreal Neurological Institute-Hospital and Departments of Neurology & Neurosurgery, McGill University, 3801 Rue University, Montreal, H3A 2B4, QC, Canada.
| | - Siyan Wang
- Montreal Neurological Institute-Hospital and Departments of Neurology & Neurosurgery, McGill University, 3801 Rue University, Montreal, H3A 2B4, QC, Canada
| | - Anežka D B Macey-Dare
- Montreal Neurological Institute-Hospital and Departments of Neurology & Neurosurgery, McGill University, 3801 Rue University, Montreal, H3A 2B4, QC, Canada; Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK
| | - Pariya Salami
- Montreal Neurological Institute-Hospital and Departments of Neurology & Neurosurgery, McGill University, 3801 Rue University, Montreal, H3A 2B4, QC, Canada; Department of Neurology, Massachusetts General Hospital and Harvard Medical School, 55 Fruit St., Boston, MA 02114, USA
| | - Massimo Avoli
- Montreal Neurological Institute-Hospital and Departments of Neurology & Neurosurgery, McGill University, 3801 Rue University, Montreal, H3A 2B4, QC, Canada; Department of Physiology, McGill University, 3655 Promenade Sir William Osler, Montreal, H3G 1Y6, QC, Canada
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21
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Naylor DE. In the fast lane: Receptor trafficking during status epilepticus. Epilepsia Open 2023; 8 Suppl 1:S35-S65. [PMID: 36861477 PMCID: PMC10173858 DOI: 10.1002/epi4.12718] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Accepted: 02/23/2023] [Indexed: 03/03/2023] Open
Abstract
Status epilepticus (SE) remains a significant cause of morbidity and mortality and often is refractory to standard first-line treatments. A rapid loss of synaptic inhibition and development of pharmacoresistance to benzodiazepines (BZDs) occurs early during SE, while NMDA and AMPA receptor antagonists remain effective treatments after BZDs have failed. Multimodal and subunit-selective receptor trafficking within minutes to an hour of SE involves GABA-A, NMDA, and AMPA receptors and contributes to shifts in the number and subunit composition of surface receptors with differential impacts on the physiology, pharmacology, and strength of GABAergic and glutamatergic currents at synaptic and extrasynaptic sites. During the first hour of SE, synaptic GABA-A receptors containing γ2 subunits move to the cell interior while extrasynaptic GABA-A receptors with δ subunits are preserved. Conversely, NMDA receptors containing N2B subunits are increased at synaptic and extrasynaptic sites, and homomeric GluA1 ("GluA2-lacking") calcium permeant AMPA receptor surface expression also is increased. Molecular mechanisms, largely driven by NMDA receptor or calcium permeant AMPA receptor activation early during circuit hyperactivity, regulate subunit-specific interactions with proteins involved with synaptic scaffolding, adaptin-AP2/clathrin-dependent endocytosis, endoplasmic reticulum (ER) retention, and endosomal recycling. Reviewed here is how SE-induced shifts in receptor subunit composition and surface representation increase the excitatory to inhibitory imbalance that sustains seizures and fuels excitotoxicity contributing to chronic sequela such as "spontaneous recurrent seizures" (SRS). A role for early multimodal therapy is suggested both for treatment of SE and for prevention of long-term comorbidities.
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Affiliation(s)
- David E Naylor
- VA Greater Los Angeles Healthcare System, Department of Neurology, David Geffen School of Medicine at UCLA, and The Lundquist Institute at Harbor-UCLA Medical Center, Los Angeles, California, USA
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22
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Yang Y, Zhang F, Gao X, Feng L, Xu K. Progressive alterations in electrophysiological and epileptic network properties during the development of temporal lobe epilepsy in rats. Epilepsy Behav 2023; 141:109120. [PMID: 36868167 DOI: 10.1016/j.yebeh.2023.109120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 01/28/2023] [Accepted: 01/29/2023] [Indexed: 03/05/2023]
Abstract
OBJECTIVE Refractory temporal lobe epilepsy (TLE) with recurring seizures causing continuing pathological changes in neural reorganization. There is an incomplete understanding of how spatiotemporal electrophysiological characteristics changes during the development of TLE. Long-term multi-site epilepsy patients' data is hard to obtain. Thus, our study relied on animal models to reveal the changes in electrophysiological and epileptic network characteristics systematically. METHODS Long-term local field potentials (LFPs) were recorded over a period of 1 to 4 months from 6 pilocarpine-treated TLE rats. We compared variations of seizure onset zone (SOZ), seizure onset pattern (SOP), the latency of seizure onsets, and functional connectivity network from 10-channel LFPs between the early and late stages. Moreover, three machine learning classifiers trained by early-stage data were used to test seizure detection performance in the late stage. RESULTS Compared to the early stage, the earliest seizure onset was more frequently detected in hippocampus areas in the late stage. The latency of seizure onsets between electrodes became shorter. Low-voltage fast activity (LVFA) was the most common SOP and the proportion of it increased in the late stage. Different brain states were observed during seizures using Granger causality (GC). Moreover, seizure detection classifiers trained by early-stage data were less accurate when tested in late-stage data. SIGNIFICANCE Neuromodulation especially closed-loop deep brain stimulation (DBS) is effective in the treatment of refractory TLE. Although the frequency or amplitude of the stimulation is generally adjusted in existing closed-loop DBS devices in clinical usage, the adjustment rarely considers the pathological progression of chronic TLE. This suggests that an important factor affecting the therapeutic effect of neuromodulation may have been overlooked. The present study reveals time-varying electrophysiological and epileptic network properties in chronic TLE rats and indicates that classifiers of seizure detection and neuromodulation parameters might be designed to adapt to the current state dynamically with the progression of epilepsy.
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Affiliation(s)
- Yufang Yang
- Qiushi Academy for Advanced Studies, Zhejiang University, Hangzhou, China; Zhejiang Provincial Key Laboratory of Cardio-Cerebral Vascular Detection Technology and Medicinal Effectiveness Appraisal, Key Laboratory of Biomedical Engineering of Education Ministry, Department of Biomedical Engineering, Zhejiang University, Hangzhou, China.
| | - Fang Zhang
- Qiushi Academy for Advanced Studies, Zhejiang University, Hangzhou, China; Zhejiang Provincial Key Laboratory of Cardio-Cerebral Vascular Detection Technology and Medicinal Effectiveness Appraisal, Key Laboratory of Biomedical Engineering of Education Ministry, Department of Biomedical Engineering, Zhejiang University, Hangzhou, China.
| | - Xiang Gao
- Zhejiang Provincial Key Laboratory of Cardio-Cerebral Vascular Detection Technology and Medicinal Effectiveness Appraisal, Key Laboratory of Biomedical Engineering of Education Ministry, Department of Biomedical Engineering, Zhejiang University, Hangzhou, China; Institute of Advanced Digital Technology and Instrument, Zhejiang University, Hangzhou, China.
| | | | - Kedi Xu
- Qiushi Academy for Advanced Studies, Zhejiang University, Hangzhou, China; Zhejiang Provincial Key Laboratory of Cardio-Cerebral Vascular Detection Technology and Medicinal Effectiveness Appraisal, Key Laboratory of Biomedical Engineering of Education Ministry, Department of Biomedical Engineering, Zhejiang University, Hangzhou, China; The MOE Frontier Science Center for Brain Science and Brain-machine Integration, Hangzhou, China.
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23
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Yi TT, Zhang LM, Huang XN. Glycyrrhizic acid protects against temporal lobe epilepsy in young rats by regulating neuronal ferroptosis through the miR-194-5p/PTGS2 axis. Kaohsiung J Med Sci 2023; 39:154-165. [PMID: 36647717 DOI: 10.1002/kjm2.12642] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Revised: 08/29/2022] [Accepted: 09/15/2022] [Indexed: 01/18/2023] Open
Abstract
Temporal lobe epilepsy (TLE) leads to extensive degradation of the quality of life of patients. Glycyrrhizic acid (GA) has been reported to exert neuroprotective effects on status epilepticus. Herein, the current study set out to explore the functional mechanism of GA in TLE young rats. Firstly, TLE young rat models were established using the lithium chloride and pilocarpine regimen and then subjected to treatment with different doses of GA, miR-194-5p-antagomir, or/and sh-prostaglandin-endoperoxide synthase 2 (PTGS2) to observe changes in iron content, glutathione and malondialdehyde levels, and GPX4 (glutathione peroxidase 4) and PTGS2 protein levels in the hippocampus. Neuronal injury and apoptosis were assessed through HE, Nissl, and TUNEL staining. Additionally, the expression patterns of miR-194-5p were detected. The binding site of miR-194-5p and PTGS2 was verified with a dual-luciferase assay. Briefly, different doses of GA (20, 40, and 60 mg/kg) reduced the epileptic score, frequency, and duration in TLE young rats, along with reductions in iron content, lipid peroxidation, neuronal injury, and apoptosis in the hippocampus. Silencing of miR-194-5p partly annulled the action of GA on inhibiting ferroptosis and attenuating neuronal injury in TLE young rats. Additionally, PTGS2 was validated as a target of miR-194-5p. GA inhibited ferroptosis and ameliorated neuronal injury in TLE young rats via the miR-194-5p/PTGS2 axis. Overall, our findings indicated that GA exerts protective effects on TLE young rats against neuronal injury by inhibiting ferroptosis through the miR-194-5p/PTGS2 axis.
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Affiliation(s)
- Ting-Ting Yi
- Department of Neurology, The Second Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China
| | - Li-Mei Zhang
- Department of Neurology, The Second Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China
| | - Xiang-Nan Huang
- Department of Neurology, The Second Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China
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24
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Löscher W, Stafstrom CE. Epilepsy and its neurobehavioral comorbidities: Insights gained from animal models. Epilepsia 2023; 64:54-91. [PMID: 36197310 DOI: 10.1111/epi.17433] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 10/04/2022] [Accepted: 10/04/2022] [Indexed: 01/21/2023]
Abstract
It is well established that epilepsy is associated with numerous neurobehavioral comorbidities, with a bidirectional relationship; people with epilepsy have an increased incidence of depression, anxiety, learning and memory difficulties, and numerous other psychosocial challenges, and the occurrence of epilepsy is higher in individuals with those comorbidities. Although the cause-and-effect relationship is uncertain, a fuller understanding of the mechanisms of comorbidities within the epilepsies could lead to improved therapeutics. Here, we review recent data on epilepsy and its neurobehavioral comorbidities, discussing mainly rodent models, which have been studied most extensively, and emphasize that clinically relevant information can be gained from preclinical models. Furthermore, we explore the numerous potential factors that may confound the interpretation of emerging data from animal models, such as the specific seizure induction method (e.g., chemical, electrical, traumatic, genetic), the role of species and strain, environmental factors (e.g., laboratory environment, handling, epigenetics), and the behavioral assays that are chosen to evaluate the various aspects of neural behavior and cognition. Overall, the interplay between epilepsy and its neurobehavioral comorbidities is undoubtedly multifactorial, involving brain structural changes, network-level differences, molecular signaling abnormalities, and other factors. Animal models are well poised to help dissect the shared pathophysiological mechanisms, neurological sequelae, and biomarkers of epilepsy and its comorbidities.
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Affiliation(s)
- Wolfgang Löscher
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine, Hannover, Germany.,Center for Systems Neuroscience, Hannover, Germany
| | - Carl E Stafstrom
- Division of Pediatric Neurology, Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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25
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Kang W, Ju C, Joo J, Lee J, Shon YM, Park SM. Closed-loop direct control of seizure focus in a rodent model of temporal lobe epilepsy via localized electric fields applied sequentially. Nat Commun 2022; 13:7805. [PMID: 36528681 PMCID: PMC9759546 DOI: 10.1038/s41467-022-35540-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 12/09/2022] [Indexed: 12/23/2022] Open
Abstract
Direct electrical stimulation of the seizure focus can achieve the early termination of epileptic oscillations. However, direct intervention of the hippocampus, the most prevalent seizure focus in temporal lobe epilepsy is thought to be not practicable due to its large size and elongated shape. Here, in a rat model, we report a sequential narrow-field stimulation method for terminating seizures, while focusing stimulus energy at the spatially extensive hippocampal structure. The effects and regional specificity of this method were demonstrated via electrophysiological and biological responses. Our proposed modality demonstrates spatiotemporal preciseness and selectiveness for modulating the pathological target region which may have potential for further investigation as a therapeutic approach.
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Affiliation(s)
- Wonok Kang
- School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
- Medical Device Innovation Center, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
| | - Chanyang Ju
- Medical Device Innovation Center, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
- Department of Convergence IT Engineering, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
| | - Jaesoon Joo
- Biomedical Engineering Research Center, Samsung Medical Center, School of Medicine, Sungkyunkwan University, Seoul, 06351, South Korea
| | - Jiho Lee
- Medical Device Innovation Center, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
- Department of Convergence IT Engineering, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
| | - Young-Min Shon
- Biomedical Engineering Research Center, Samsung Medical Center, School of Medicine, Sungkyunkwan University, Seoul, 06351, South Korea.
- Department of Neurology, Samsung Medical Center, School of Medicine, Sungkyunkwan University, Seoul, 06351, Republic of Korea.
| | - Sung-Min Park
- School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea.
- Medical Device Innovation Center, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea.
- Department of Convergence IT Engineering, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea.
- Department of Electrical Engineering, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea.
- Department of Mechanical Engineering, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea.
- Institute of Convergence Science, Yonsei University, Seoul, 03722, Republic of Korea.
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26
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Doublet T, Ghestem A, Bernard C. Deficit in observational learning in experimental epilepsy. Epilepsia 2022; 63:e150-e155. [PMID: 36197904 PMCID: PMC10092486 DOI: 10.1111/epi.17421] [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: 06/27/2022] [Revised: 09/26/2022] [Accepted: 09/26/2022] [Indexed: 01/11/2023]
Abstract
Individuals use the observation of a conspecific to learn new behaviors and skills in many species. Whether observational learning is affected in epilepsy is not known. Using the pilocarpine rat model of epilepsy, we assessed learning by observation in a spatial task. The task involves a naive animal observing a demonstrator animal seeking a reward at a specific spatial location. After five observational sessions, the observer is allowed to explore the rewarded space and look for the reward. Although control observer rats succeed in finding the reward when allowed to explore the rewarded space, epileptic animals fail. However, epileptic animals are able to successfully learn the location of the reward through their own experience after several trial sessions. Thus, epileptic animals show a clear deficit in learning by observation. This result may be clinically relevant, in particular in children who strongly rely on observational learning.
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Affiliation(s)
- Thomas Doublet
- Institute of Systems Neuroscience, Aix-Marseille University, Marseille, France
| | - Antoine Ghestem
- Institute of Systems Neuroscience, Aix-Marseille University, Marseille, France
| | - Christophe Bernard
- Institute of Systems Neuroscience, Aix-Marseille University, Marseille, France
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27
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Mohammadi E, Nikbakht F, Barati M, Roghani M, Vazifekhah S, Khanizadeh AM, Heidari Z. Protective effect of N-acetyl cysteine on the mitochondrial dynamic imbalance in temporal lobe epilepsy: Possible role of mTOR. Neuropeptides 2022; 96:102294. [PMID: 36270032 DOI: 10.1016/j.npep.2022.102294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 10/05/2022] [Accepted: 10/05/2022] [Indexed: 11/07/2022]
Abstract
Understanding the underlying molecular mechanisms involved in epilepsy is critical for the development of more effective therapies. It is believed that mTOR (Mechanistic Target of Rapamycin kinases) activity and the mitochondrial dynamic balance change during epilepsy. mTOR affects mitochondrial fission by stimulating the translation of mitochondrial fission process 1 (MTFP1). In This study, the protective role of N-acetylcysteine was studied in temporal lobe epilepsy (TLE) through the regulation of mTOR and mitochondrial dynamic proteins. Rats received N-acetylcysteine (oral administration) seven days before induction of epilepsy, followed by one day after epilepsy. TLE was induced by microinjection of kainite into the left lateral ventricle. The total mTOR and Drp1 levels in the hippocampus were evaluated by western blotting. MFN1 was assessed using immunohistochemistry, and the expression of Fis.1 and MTFP1 (fission-related proteins) and OPA (fusion-related protein) were detected by real-time PCR. The mitochondrial membrane potential was measured by Rhodamin 123. The results showed that 72 h after induction of epilepsy, the mTOR protein level increased, and the balance of the mitochondrial dynamic was disturbed; however, oral administration of NAC decreased the mTOR protein level and improved the mitochondrial dynamic. These findings indicate that NAC plays a neuroprotective role in temporal lobe epilepsy, probably through decreasing the mTOR protein level, which can improve the imbalance in the mitochondrial dynamic.
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Affiliation(s)
- Ekram Mohammadi
- Cellular and Molecular Research Center and Department of Physiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Farnaz Nikbakht
- Cellular and Molecular Research Center and Department of Physiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran.
| | - Mahmoud Barati
- Department of Medical Biotechnology, School of Allied Medical Sciences, Iran University of Medical Sciences, Iran
| | - Mehrdad Roghani
- Neurophysiology Research Center, Shahed University, Tehran, Iran
| | - Somayeh Vazifekhah
- Cellular and Molecular Research Center and Department of Physiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Ali Mohammad Khanizadeh
- Cellular and Molecular Research Center and Department of Physiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Zahra Heidari
- Cellular and Molecular Research Center and Department of Physiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
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28
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Differential Levels of Tryptophan-Kynurenine Pathway Metabolites in the Hippocampus, Anterior Temporal Lobe, and Neocortex in an Animal Model of Temporal Lobe Epilepsy. Cells 2022; 11:cells11223560. [PMID: 36428989 PMCID: PMC9688794 DOI: 10.3390/cells11223560] [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: 09/30/2022] [Revised: 11/07/2022] [Accepted: 11/08/2022] [Indexed: 11/12/2022] Open
Abstract
Glutamate-receptor-mediated hyperexcitability contributes to seizure generation in temporal lobe epilepsy (TLE). Tryptophan-kynurenine pathway (TKP) metabolites regulate glutamate receptor activity under physiological conditions. This study was designed to investigate alterations in the levels of TKP metabolites and the differential regulation of glutamatergic activity by TKP metabolites in the hippocampus, anterior temporal lobe (ATL), and neocortex samples of a lithium-pilocarpine rat model of TLE. We observed that levels of tryptophan were reduced in the hippocampus and ATL samples but unaltered in the neocortex samples. The levels of kynurenic acid were reduced in the hippocampus samples and unaltered in the ATL and neocortex samples of the TLE rats. The levels of kynurenine were unaltered in all three regions of the TLE rats. The magnitude of reduction in these metabolites in all regions was unaltered in the TLE rats. The frequency and amplitude of spontaneous excitatory postsynaptic currents were enhanced in hippocampus ATL samples but not in the neocortex samples of the TLE rats. The exogenous application of kynurenic acid inhibited glutamatergic activity in the slice preparations of all these regions in both the control and the TLE rats. However, the magnitude of reduction in the frequency of kynurenic acid was higher in the hippocampus (18.44 ± 2.6% in control vs. 30.02 ± 1.5 in TLE rats) and ATL (16.31 ± 0.91% in control vs. 29.82 ± 3.08% in TLE rats) samples of the TLE rats. These findings suggest the differential regulation of glutamatergic activity by TKP metabolites in the hippocampus, ATL, and neocortex of TLE rats.
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29
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Wang R, Zhu W, Liang G, Xu J, Guo J, Wang L. Animal models for epileptic foci localization, seizure detection, and prediction by electrical impedance tomography. WILEY INTERDISCIPLINARY REVIEWS. COGNITIVE SCIENCE 2022; 13:e1619. [PMID: 36093634 DOI: 10.1002/wcs.1619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 07/08/2022] [Accepted: 07/14/2022] [Indexed: 06/15/2023]
Abstract
Surgical resection of lesions and closed-loop suppression are the two main treatment options for patients with refractory epilepsy whose symptoms cannot be managed with medicines. Unfortunately, failures in foci localization and seizure prediction are constraining these treatments. Electrical impedance tomography (EIT), sensitive to impedance changes caused by blood flow or cell swelling, is a potential new way to locate epileptic foci and predict seizures. Animal validation is a necessary research process before EIT can be used in clinical practice, but it is unclear which among the many animal epilepsy models is most suited to this task. The selection of an animal model of epilepsy that is similar to human seizures and can be adapted to EIT is important for the accuracy and reliability of EIT research results. This study provides an overview of the animal models of epilepsy that have been used in research on the use of EIT to locate the foci or predict seizures; discusses the advantages and disadvantages of these models regarding inducement by chemical convulsant and electrical stimulation; and finally proposes optimal animal models of epilepsy to obtain more convincing research results for foci localization and seizure prediction by EIT. The ultimate goal of this study is to facilitate the development of new treatments for patients with refractory epilepsy. This article is categorized under: Neuroscience > Clinical Neuroscience Psychology > Brain Function and Dysfunction.
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Affiliation(s)
- Rong Wang
- Institute of Medical Research, Northwestern Polytechnical University, Xi'an, China
| | - Wenjing Zhu
- Institute of Medical Research, Northwestern Polytechnical University, Xi'an, China
| | - Guohua Liang
- Institute of Medical Research, Northwestern Polytechnical University, Xi'an, China
| | - Jiaming Xu
- Institute of Medical Research, Northwestern Polytechnical University, Xi'an, China
| | - Jie Guo
- Institute of Medical Research, Northwestern Polytechnical University, Xi'an, China
| | - Lei Wang
- Institute of Medical Research, Northwestern Polytechnical University, Xi'an, China
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30
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Kandeda AK, Nodeina S, Mabou ST. An aqueous extract of Syzygium cumini protects against kainate-induced status epilepticus and amnesia: evidence for antioxidant and anti-inflammatory intervention. Metab Brain Dis 2022; 37:2581-2602. [PMID: 35916986 DOI: 10.1007/s11011-022-01052-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 07/12/2022] [Indexed: 10/16/2022]
Abstract
Temporal lobe epilepsy is the most common drug-resistant epilepsy. To cure epilepsy, drugs must target the mechanisms at the origin of seizures. Thus, the present investigation aimed to evaluate the antiepileptic- and anti-amnesic-like effects of an aqueous extract of Syzygium cumini against kainate-induced status epilepticus in mice, and possible mechanisms of action. Mice were divided into 7 groups and treated as follows: normal group or kainate group received po distilled water (10 mL/kg), four test groups received Syzygium cumini (28.8, 72, 144, and 288 mg/kg, po), and the positive control group treated intraperitoneally (ip) with sodium valproate (300 mg/kg). An extra group of normal mice was treated with piracetam (200 mg/kg, po). Treatments were administered 60 min before the induction of status epilepticus with kainate (15 mg/kg, ip), and continued daily throughout behavioral testing. Twenty-four hours after the induction, T-maze and Morris water maze tasks were successively performed. The animals were then sacrificed and some markers of oxidative stress and neuroinflammation were estimated in the hippocampus. The extract significantly prevented status epilepticus and mortality. In the T-maze, the aqueous extract markedly increased the time spent and the number of entries in the discriminated arm. In the Morris water maze, the extract significantly increased the time spent in the target quadrant during the retention phase. Furthermore, the aqueous extract induced a significant reduction of oxidative stress and neuroinflammation. These results suggest that the aqueous extract of Syzygium cumini has antiepileptic- and anti-amnesic-like effects, likely mediated in part by antioxidant and anti-inflammatory activities.
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Affiliation(s)
- Antoine Kavaye Kandeda
- Department of Animal Biology and Physiology, Faculty of Science, University of Yaoundé I, P.O. Box 812, Yaoundé, Cameroon.
- Department of Animal Biology and Physiology, University of Yaoundé I, P.O. Box 812, Yaoundé, Cameroon.
| | - Saleh Nodeina
- Department of Biological Sciences, Faculty of Science, University of Ngaoundéré, P.O. Box 454, Ngaoundéré, Cameroon
| | - Symphorien Talom Mabou
- Department of Animal Biology and Physiology, Faculty of Science, University of Yaoundé I, P.O. Box 812, Yaoundé, Cameroon
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31
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Chakraborty S, Parayil R, Mishra S, Nongthomba U, Clement JP. Epilepsy Characteristics in Neurodevelopmental Disorders: Research from Patient Cohorts and Animal Models Focusing on Autism Spectrum Disorder. Int J Mol Sci 2022; 23:ijms231810807. [PMID: 36142719 PMCID: PMC9501968 DOI: 10.3390/ijms231810807] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Revised: 08/31/2022] [Accepted: 09/05/2022] [Indexed: 11/24/2022] Open
Abstract
Epilepsy, a heterogeneous group of brain-related diseases, has continued to significantly burden society and families. Epilepsy comorbid with neurodevelopmental disorders (NDDs) is believed to occur due to multifaceted pathophysiological mechanisms involving disruptions in the excitation and inhibition (E/I) balance impeding widespread functional neuronal circuitry. Although the field has received much attention from the scientific community recently, the research has not yet translated into actionable therapeutics to completely cure epilepsy, particularly those comorbid with NDDs. In this review, we sought to elucidate the basic causes underlying epilepsy as well as those contributing to the association of epilepsy with NDDs. Comprehensive emphasis is put on some key neurodevelopmental genes implicated in epilepsy, such as MeCP2, SYNGAP1, FMR1, SHANK1-3 and TSC1, along with a few others, and the main electrophysiological and behavioral deficits are highlighted. For these genes, the progress made in developing appropriate and valid rodent models to accelerate basic research is also detailed. Further, we discuss the recent development in the therapeutic management of epilepsy and provide a briefing on the challenges and caveats in identifying and testing species-specific epilepsy models.
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Affiliation(s)
- Sukanya Chakraborty
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru 560064, India
| | - Rrejusha Parayil
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru 560064, India
| | - Shefali Mishra
- Molecular Reproduction, Development and Genetics (MRDG), Indian Institute of Science, Bengaluru 560012, India
| | - Upendra Nongthomba
- Molecular Reproduction, Development and Genetics (MRDG), Indian Institute of Science, Bengaluru 560012, India
| | - James P. Clement
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru 560064, India
- Correspondence: ; Tel.: +91-08-2208-2613
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Dynamics of neurodegeneration in the hippocampus of Krushinsky-Molodkina rats correlates with the progression of limbic seizures. Epilepsy Behav 2022; 134:108846. [PMID: 35849865 DOI: 10.1016/j.yebeh.2022.108846] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 06/17/2022] [Accepted: 07/04/2022] [Indexed: 11/21/2022]
Abstract
Audiogenic seizures (AGS) (audiogenic kindling) in genetically selected audiogenic rodents are a reliable model of temporal lobe epilepsy (TLE). Temporal lobe epilepsy is accompanied with neurodegeneration in the hippocampus, but how the cells die is not fully understood. We analyzed the dynamics and mechanisms of cell loss in the hippocampus of audiogenic Krushinsky-Molodkina (KM) rats during the development of TLE. Audiogenic kindling of different durations was carried out to reproduce TLE progression in KM rats. Behavioral analysis showed the development of post-tonic clonus, the main indicator of TLE, by the 14th AGS. The severity and duration of post-tonic clonus positively correlated with the increase in the number of AGS. Temporal lobe epilepsy development was accompanied with two peaks of cell loss. The first peak was detected after 7 AGS in the dentate gyrus (DG) granular layer and associated with activation of p53- and mitochondria-dependent apoptosis. After a 7-day rest period, activation of autophagy and restoration of cell number were revealed. The second peak occurred after 14 AGS, affected both granular and hilar mossy cells and persisted further after 21 AGS, but no compensation was observed. Thus, activation of autophagy probably plays a neuroprotective role and supports survival of hippocampal cells at the beginning of epileptogenesis, but exacerbation of limbic seizures during TLE development causes irreversible neurodegeneration.
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Gorlewicz A, Barthet G, Zucca S, Vincent P, Griguoli M, Grosjean N, Wilczynski G, Mulle C. The Deletion of GluK2 Alters Cholinergic Control of Neuronal Excitability. Cereb Cortex 2022; 32:2907-2923. [PMID: 34730179 DOI: 10.1093/cercor/bhab390] [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: 05/29/2020] [Revised: 09/28/2021] [Accepted: 09/29/2021] [Indexed: 11/14/2022] Open
Abstract
Kainate receptors (KARs) are key regulators of synaptic circuits by acting at pre- and postsynaptic sites through either ionotropic or metabotropic actions. KARs can be activated by kainate, a potent neurotoxin, which induces acute convulsions. Here, we report that the acute convulsive effect of kainate mostly depends on GluK2/GluK5 containing KARs. By contrast, the acute convulsive activity of pilocarpine and pentylenetetrazol is not alleviated in the absence of KARs. Unexpectedly, the genetic inactivation of GluK2 rather confers increased susceptibility to acute pilocarpine-induced seizures. The mechanism involves an enhanced excitability of GluK2-/- CA3 pyramidal cells compared with controls upon pilocarpine application. Finally, we uncover that the absence of GluK2 increases pilocarpine modulation of Kv7/M currents. Taken together, our findings reveal that GluK2-containing KARs can control the excitability of hippocampal circuits through interaction with the neuromodulatory cholinergic system.
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Affiliation(s)
- Adam Gorlewicz
- Interdisciplinary Institute for Neuroscience, UMR 5297, Centre National de la Recherche Scientifique, F-33000 Bordeaux, France
- Interdisciplinary Institute for Neuroscience, UMR 5297, University of Bordeaux, F-33000 Bordeaux, France
- Laboratory of Molecular and Systemic Neuromorphology, Nencki Institute of Experimental Biology, 02-093 Warsaw, Poland
| | - Gael Barthet
- Interdisciplinary Institute for Neuroscience, UMR 5297, Centre National de la Recherche Scientifique, F-33000 Bordeaux, France
- Interdisciplinary Institute for Neuroscience, UMR 5297, University of Bordeaux, F-33000 Bordeaux, France
| | - Stefano Zucca
- Interdisciplinary Institute for Neuroscience, UMR 5297, Centre National de la Recherche Scientifique, F-33000 Bordeaux, France
- Interdisciplinary Institute for Neuroscience, UMR 5297, University of Bordeaux, F-33000 Bordeaux, France
| | - Peggy Vincent
- Interdisciplinary Institute for Neuroscience, UMR 5297, Centre National de la Recherche Scientifique, F-33000 Bordeaux, France
- Interdisciplinary Institute for Neuroscience, UMR 5297, University of Bordeaux, F-33000 Bordeaux, France
| | - Marilena Griguoli
- Interdisciplinary Institute for Neuroscience, UMR 5297, Centre National de la Recherche Scientifique, F-33000 Bordeaux, France
- Interdisciplinary Institute for Neuroscience, UMR 5297, University of Bordeaux, F-33000 Bordeaux, France
| | - Noëlle Grosjean
- Interdisciplinary Institute for Neuroscience, UMR 5297, Centre National de la Recherche Scientifique, F-33000 Bordeaux, France
- Interdisciplinary Institute for Neuroscience, UMR 5297, University of Bordeaux, F-33000 Bordeaux, France
| | - Grzegorz Wilczynski
- Laboratory of Molecular and Systemic Neuromorphology, Nencki Institute of Experimental Biology, 02-093 Warsaw, Poland
| | - Christophe Mulle
- Interdisciplinary Institute for Neuroscience, UMR 5297, Centre National de la Recherche Scientifique, F-33000 Bordeaux, France
- Interdisciplinary Institute for Neuroscience, UMR 5297, University of Bordeaux, F-33000 Bordeaux, France
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Respiratory dysfunction in two rodent models of chronic epilepsy and acute seizures and its link with the brainstem serotonin system. Sci Rep 2022; 12:10248. [PMID: 35715469 PMCID: PMC9205882 DOI: 10.1038/s41598-022-14153-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 06/02/2022] [Indexed: 11/22/2022] Open
Abstract
Patients with drug-resistant epilepsy can experience respiratory alterations, notably during seizures. The mechanisms underlying long-term alterations in respiratory function remain unclear. As the brainstem 5-HT system is a prominent modulator of respiratory function, this study aimed at determining whether epilepsy is associated with alterations in both the respiratory function and brainstem serotonin (5-HT) system in rats. Epilepsy was triggered by pilocarpine-induced status epilepticus in rats. Our results showed that 30–50% of epileptic (EPI) rats exhibited a sharp decrease in oxygen consumption (SDOC), low metabolic rate of oxygen, and slow regular ventilation (EPI/SDOC + rats). These alterations were detected only in rats with chronic epilepsy, independent of behavioral seizures, were persistent over time, and not associated with death. In these rats, 5-HT fiber density in the nucleus tractus solitarius was lower than that in the control and EPI/SDOC− rats. Both EPI/SDOC + rats and DBA/2 mice that present with audiogenic-induced seizure followed by fatal respiratory arrest—a model of sudden and expected death in epilepsy—had increased transcript levels of tryptophan hydroxylase 2 and 5-HT presynaptic transporter. Thus, our data support that 5-HT alterations are associated with chronic and acute epilepsy-related respiratory dysfunction.
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SCN1A overexpression, associated with a genomic region marked by a risk variant for a common epilepsy, raises seizure susceptibility. Acta Neuropathol 2022; 144:107-127. [PMID: 35551471 PMCID: PMC9217876 DOI: 10.1007/s00401-022-02429-0] [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: 03/16/2022] [Revised: 04/29/2022] [Accepted: 04/30/2022] [Indexed: 11/01/2022]
Abstract
Mesial temporal lobe epilepsy with hippocampal sclerosis and a history of febrile seizures is associated with common variation at rs7587026, located in the promoter region of SCN1A. We sought to explore possible underlying mechanisms. SCN1A expression was analysed in hippocampal biopsy specimens of individuals with mesial temporal lobe epilepsy with hippocampal sclerosis who underwent surgical treatment, and hippocampal neuronal cell loss was quantitatively assessed using immunohistochemistry. In healthy individuals, hippocampal volume was measured using MRI. Analyses were performed stratified by rs7587026 type. To study the functional consequences of increased SCN1A expression, we generated, using transposon-mediated bacterial artificial chromosome transgenesis, a zebrafish line expressing exogenous scn1a, and performed EEG analysis on larval optic tecta at 4 day post-fertilization. Finally, we used an in vitro promoter analysis to study whether the genetic motif containing rs7587026 influences promoter activity. Hippocampal SCN1A expression differed by rs7587026 genotype (Kruskal-Wallis test P = 0.004). Individuals homozygous for the minor allele showed significantly increased expression compared to those homozygous for the major allele (Dunn's test P = 0.003), and to heterozygotes (Dunn's test P = 0.035). No statistically significant differences in hippocampal neuronal cell loss were observed between the three genotypes. Among 597 healthy participants, individuals homozygous for the minor allele at rs7587026 displayed significantly reduced mean hippocampal volume compared to major allele homozygotes (Cohen's D = - 0.28, P = 0.02), and to heterozygotes (Cohen's D = - 0.36, P = 0.009). Compared to wild type, scn1lab-overexpressing zebrafish larvae exhibited more frequent spontaneous seizures [one-way ANOVA F(4,54) = 6.95 (P < 0.001)]. The number of EEG discharges correlated with the level of scn1lab overexpression [one-way ANOVA F(4,15) = 10.75 (P < 0.001]. Finally, we showed that a 50 bp promoter motif containing rs7587026 exerts a strong regulatory role on SCN1A expression, though we could not directly link this to rs7587026 itself. Our results develop the mechanistic link between rs7587026 and mesial temporal lobe epilepsy with hippocampal sclerosis and a history of febrile seizures. Furthermore, we propose that quantitative precision may be important when increasing SCN1A expression in current strategies aiming to treat seizures in conditions involving SCN1A haploinsufficiency, such as Dravet syndrome.
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An aqueous extract of Khaya senegalensis (Desv.) A. Juss. (Meliaceae) prevents seizures and reduces anxiety in kainate-treated rats: modulation of GABA neurotransmission, oxidative stress, and neuronal loss in the hippocampus. Heliyon 2022; 8:e09549. [PMID: 35663738 PMCID: PMC9160348 DOI: 10.1016/j.heliyon.2022.e09549] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 03/28/2022] [Accepted: 05/23/2022] [Indexed: 11/22/2022] Open
Abstract
Ethnopharmacological relevance Temporal lobe epilepsy is the most common form of drug-resistant epilepsy. Therefore, medicinal plants provide an alternative source for the discovery of new antiepileptic drugs. Aim of the study This study was aimed at investigating the antiepileptic- and anxiolytic-like effects of an aqueous extract of Khaya senegalensis (K. senegalensis) in kainate-treated rats. Methods Seventy-two rats received a single dose of kainate (12 mg/kg) intraperitoneally. Those that exhibited two hours of status epilepticus were selected and monitored for the first spontaneous seizure. Then, animals that developed seizures were divided into 6 groups of 8 rats each and treated twice daily for 14 days as follows: negative control group received per os (p.o.) distilled water (10 ml/kg); two positive control groups received either sodium valproate (300 mg/kg, p.o.) or phenobarbital (20 mg/kg, p.o.); and three test groups received different doses of the extract (50, 100, and 200 mg/kg, p.o.). In addition, a group of 8 normal rats (normal control group) received distilled water (10 ml/kg, p.o.). During the treatment period, the animals were video-monitored 12 h/day for behavioral seizures. At the end of the treatment period, animals were subjected to elevated plus-maze and open field tests. Thereafter, rats were euthanized for the analysis of γ-aminobutyric acid (GABA) concentration, oxidative stress status, and neuronal loss in the hippocampus. Results The aqueous extract of K. senegalensis significantly reduced spontaneous recurrent seizures (generalized tonic-clonic seizures) and anxiety-like behavior compared to the negative control group. These effects were more marked than those of sodium valproate or phenobarbital. Furthermore, the extract significantly increased GABA concentration, alleviated oxidative stress, and mitigated neuronal loss in the dentate gyrus of the hippocampus. Conclusion These findings suggest that the aqueous extract of K. senegalensis possesses antiepileptic- and anxiolytic-like effects. These effects were greater than those of sodium valproate or phenobarbital, standard antiepileptic drugs. Furthermore, these effects are accompanied by neuromodulatory and antioxidant activities that may be related to their behavioral effects. These data justify further studies to identify the bioactive molecules present in the extract for possible future therapeutic development and to unravel their mechanisms of action.
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Cao Y, Sun C, Huang J, Sun P, Wang L, He S, Liao J, Lu Z, Lu Y, Zhong C. Dysfunction of the Hippocampal-Lateral Septal Circuit Impairs Risk Assessment in Epileptic Mice. Front Mol Neurosci 2022; 15:828891. [PMID: 35571372 PMCID: PMC9103201 DOI: 10.3389/fnmol.2022.828891] [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: 12/04/2021] [Accepted: 03/29/2022] [Indexed: 11/16/2022] Open
Abstract
Temporal lobe epilepsy, a chronic disease of the brain characterized by degeneration of the hippocampus, has impaired risk assessment. Risk assessment is vital for survival in complex environments with potential threats. However, the underlying mechanisms remain largely unknown. The intricate balance of gene regulation and expression across different brain regions is related to the structure and function of specific neuron subtypes. In particular, excitation/inhibition imbalance caused by hyperexcitability of glutamatergic neurons and/or dysfunction of GABAergic neurons, have been implicated in epilepsy. First, we estimated the risk assessment (RA) by evaluating the behavior of mice in the center of the elevated plus maze, and found that the kainic acid-induced temporal lobe epilepsy mice were specifically impaired their RA. This experiment evaluated approach-RA, with a forthcoming approach to the open arm, and avoid-RA, with forthcoming avoidance of the open arm. Next, results from free-moving electrophysiological recordings showed that in the hippocampus, ∼7% of putative glutamatergic neurons and ∼15% of putative GABAergic neurons were preferentially responsive to either approach-risk assessment or avoid-risk assessment, respectively. In addition, ∼12% and ∼8% of dorsal lateral septum GABAergic neurons were preferentially responsive to approach-risk assessment and avoid-risk assessment, respectively. Notably, during the impaired approach-risk assessment, the favorably activated dorsal dentate gyrus and CA3 glutamatergic neurons increased (∼9%) and dorsal dentate gyrus and CA3 GABAergic neurons decreased (∼7%) in the temporal lobe epilepsy mice. Then, we used RNA sequencing and immunohistochemical staining to investigate which subtype of GABAergic neuron loss may contribute to excitation/inhibition imbalance. The results show that temporal lobe epilepsy mice exhibit significant neuronal loss and reorganization of neural networks. In particular, the dorsal dentate gyrus and CA3 somatostatin-positive neurons and dorsal lateral septum cholecystokinin-positive neurons are selectively vulnerable to damage after temporal lobe epilepsy. Optogenetic activation of the hippocampal glutamatergic neurons or chemogenetic inhibition of the hippocampal somatostatin neurons directly disrupts RA, suggesting that an excitation/inhibition imbalance in the dHPC dorsal lateral septum circuit results in the impairment of RA behavior. Taken together, this study provides insight into epilepsy and its comorbidity at different levels, including molecular, cell, neural circuit, and behavior, which are expected to decrease injury and premature mortality in patients with epilepsy.
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Affiliation(s)
- Yi Cao
- Guangdong Provincial Key Laboratory of Brain Connectome and Behavior, CAS Key Laboratory of Brain Connectome and Manipulation, The Brain Cognition and Brain Disease Institute, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, China
- Division of Life Sciences and Medicine, School of Life Sciences, University of Science and Technology of China, Hefei, China
| | - Chongyang Sun
- Guangdong Provincial Key Laboratory of Brain Connectome and Behavior, CAS Key Laboratory of Brain Connectome and Manipulation, The Brain Cognition and Brain Disease Institute, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, China
| | - Jianyu Huang
- Guangdong Provincial Key Laboratory of Brain Connectome and Behavior, CAS Key Laboratory of Brain Connectome and Manipulation, The Brain Cognition and Brain Disease Institute, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, China
- Key Laboratory of Industrial Microbiology, College of Biotechnology, Tianjin University of Science and Technology, Tianjin, China
| | - Peng Sun
- Guangdong Provincial Key Laboratory of Brain Connectome and Behavior, CAS Key Laboratory of Brain Connectome and Manipulation, The Brain Cognition and Brain Disease Institute, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, China
- College of Electronic and Information Engineering, Hebei University, Baoding, China
| | - Lulu Wang
- Guangdong Provincial Key Laboratory of Brain Connectome and Behavior, CAS Key Laboratory of Brain Connectome and Manipulation, The Brain Cognition and Brain Disease Institute, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, China
| | - Shuyu He
- Shenzhen Children’s Hospital, China Medical University, Shenzhen, China
| | - Jianxiang Liao
- Epilepsy Center, Shenzhen Children’s Hospital, Shenzhen, China
| | - Zhonghua Lu
- Guangdong Provincial Key Laboratory of Brain Connectome and Behavior, CAS Key Laboratory of Brain Connectome and Manipulation, The Brain Cognition and Brain Disease Institute, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, China
| | - Yi Lu
- Guangdong Provincial Key Laboratory of Brain Connectome and Behavior, CAS Key Laboratory of Brain Connectome and Manipulation, The Brain Cognition and Brain Disease Institute, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, China
| | - Cheng Zhong
- Guangdong Provincial Key Laboratory of Brain Connectome and Behavior, CAS Key Laboratory of Brain Connectome and Manipulation, The Brain Cognition and Brain Disease Institute, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, China
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Wang Y, Wei P, Yan F, Luo Y, Zhao G. Animal Models of Epilepsy: A Phenotype-oriented Review. Aging Dis 2022; 13:215-231. [PMID: 35111370 PMCID: PMC8782545 DOI: 10.14336/ad.2021.0723] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Accepted: 07/23/2021] [Indexed: 12/26/2022] Open
Abstract
Epilepsy is a serious neurological disorder characterized by abnormal, recurrent, and synchronous discharges in the brain. Long-term recurrent seizure attacks can cause serious damage to brain function, which is usually observed in patients with temporal lobe epilepsy. Controlling seizure attacks is vital for the treatment and prognosis of epilepsy. Animal models, such as the kindling model, which was the most widely used model in the past, allow the understanding of the potential epileptogenic mechanisms and selection of antiepileptic drugs. In recent years, various animal models of epilepsy have been established to mimic different seizure types, without clear merits and demerits. Accordingly, this review provides a summary of the views mentioned above, aiming to provide a reference for animal model selection.
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Affiliation(s)
- Yilin Wang
- 2Institute of Cerebrovascular Diseases Research and Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Penghu Wei
- 1Department of Neurosurgery, Xuanwu Hospital of Capital Medical University, Beijing, China.,4Clinical Research Center for Epilepsy Capital Medical University, Beijing, China
| | - Feng Yan
- 2Institute of Cerebrovascular Diseases Research and Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Yumin Luo
- 2Institute of Cerebrovascular Diseases Research and Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China.,3Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China.,4Clinical Research Center for Epilepsy Capital Medical University, Beijing, China
| | - Guoguang Zhao
- 1Department of Neurosurgery, Xuanwu Hospital of Capital Medical University, Beijing, China.,3Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China.,4Clinical Research Center for Epilepsy Capital Medical University, Beijing, China
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Irannejad A, Chaitanya G, Toth E, Pizarro D, Pati S. Direct Cortical Stimulation to Probe the Ictogenicity of the Epileptogenic Nodes in Temporal Lobe Epilepsy. Front Neurol 2022; 12:761412. [PMID: 35095721 PMCID: PMC8793936 DOI: 10.3389/fneur.2021.761412] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 12/09/2021] [Indexed: 11/13/2022] Open
Abstract
Accurate mapping of the seizure onset zone (SOZ) is critical to the success of epilepsy surgery outcomes. Epileptogenicity index (EI) is a statistical method that delineates hyperexcitable brain regions involved in the generation and early propagation of seizures. However, EI can overestimate the SOZ for particular electrographic seizure onset patterns. Therefore, using direct cortical stimulation (DCS) as a probing tool to identify seizure generators, we systematically evaluated the causality of the high EI nodes (>0.3) in replicating the patient's habitual seizures. Specifically, we assessed the diagnostic yield of high EI nodes, i.e., the proportion of high EI nodes that evoked habitual seizures. A retrospective single-center study that included post-stereo encephalography (SEEG) confirmed TLE patients (n = 37) that had all high EI nodes stimulated, intending to induce a seizure. We evaluated the nodal responses (true and false responder rate) to stimulation and correlated with electrographic seizure onset patterns (hypersynchronous-HYP and low amplitude fast activity patterns-LAFA) and clinically defined SOZ. The ictogenicity (i.e., the propensity to induce the patient's habitual seizure) of a high EI node was only 44.5%. The LAFA onset pattern had a significantly higher response rate to DCS (i.e., higher evoked seizures). The concordance of an evoked habitual seizure with a clinically defined SOZ with good outcomes was over 50% (p = 0.0025). These results support targeted mapping of SOZ in LAFA onset patterns by performing DCS in high EI nodes to distinguish seizure generators (true responders) from hyperexcitable nodes that may be involved in early propagation.
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Affiliation(s)
- Auriana Irannejad
- Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, United States
- Epilepsy and Cognitive Neurophysiology Laboratory, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Ganne Chaitanya
- Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, United States
- Epilepsy and Cognitive Neurophysiology Laboratory, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Emilia Toth
- Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, United States
- Epilepsy and Cognitive Neurophysiology Laboratory, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Diana Pizarro
- Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, United States
- Epilepsy and Cognitive Neurophysiology Laboratory, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Sandipan Pati
- Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, United States
- Epilepsy and Cognitive Neurophysiology Laboratory, University of Alabama at Birmingham, Birmingham, AL, United States
- *Correspondence: Sandipan Pati
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Alvarado CD, Brewster AL. Hit by a Smooth CD8: T-Cell Attack on Hippocampal Neurons Triggers Limbic Encephalitis and Epilepsy. Epilepsy Curr 2021; 21:369-371. [PMID: 34924839 PMCID: PMC8655268 DOI: 10.1177/15357597211030175] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Breton VL, Aquilino MS, Repudi S, Saleem A, Mylvaganam S, Abu-Swai S, Bardakjian BL, Aqeilan RI, Carlen PL. Altered neocortical oscillations and cellular excitability in an in vitro Wwox knockout mouse model of epileptic encephalopathy. Neurobiol Dis 2021; 160:105529. [PMID: 34634460 PMCID: PMC8609180 DOI: 10.1016/j.nbd.2021.105529] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 09/24/2021] [Accepted: 10/07/2021] [Indexed: 12/02/2022] Open
Abstract
Loss of function mutations of the WW domain-containing oxidoreductase (WWOX) gene are associated with severe and fatal drug-resistant pediatric epileptic encephalopathy. Epileptic seizures are typically characterized by neuronal hyperexcitability; however, the specific contribution of WWOX to that hyperexcitability has yet to be investigated. Using a mouse model of neuronal Wwox-deletion that exhibit spontaneous seizures, in vitro whole-cell and field potential electrophysiological characterization identified spontaneous bursting activity in the neocortex, a marker of the underlying network hyperexcitability. Spectral analysis of the neocortical bursting events highlighted increased phase-amplitude coupling, and a propagation from layer II/III to layer V. These bursts were NMDAR and gap junction dependent. In layer II/III pyramidal neurons, Wwox knockout mice demonstrated elevated amplitude of excitatory post-synaptic currents, whereas the frequency and amplitude of inhibitory post-synaptic currents were reduced, as compared to heterozygote and wild-type littermate controls. Furthermore, these neurons were depolarized and demonstrated increased action potential frequency, sag current, and post-inhibitory rebound. These findings suggest WWOX plays an essential role in balancing neocortical excitability and provide insight towards developing therapeutics for those suffering from WWOX disorders.
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Affiliation(s)
- Vanessa L Breton
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Ontario M5S 1A8, Canada; Krembil Research Institute, Division of Fundamental Neurobiology, Toronto Western Hospital, Toronto, Ontario M5T 0S8, Canada.
| | - Mark S Aquilino
- Krembil Research Institute, Division of Fundamental Neurobiology, Toronto Western Hospital, Toronto, Ontario M5T 0S8, Canada; Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 3G9, Canada.
| | - Srinivasarao Repudi
- The Concern Foundation Laboratories, The Lautenberg Center for Immunology and Cancer Research, Immunology and Cancer Research-IMRIC, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Afifa Saleem
- Krembil Research Institute, Division of Fundamental Neurobiology, Toronto Western Hospital, Toronto, Ontario M5T 0S8, Canada; Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 3G9, Canada
| | - Shanthini Mylvaganam
- Krembil Research Institute, Division of Fundamental Neurobiology, Toronto Western Hospital, Toronto, Ontario M5T 0S8, Canada
| | - Sara Abu-Swai
- The Concern Foundation Laboratories, The Lautenberg Center for Immunology and Cancer Research, Immunology and Cancer Research-IMRIC, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Berj L Bardakjian
- Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 3G9, Canada; Edward S. Rogers Sr. Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario M5S 3G4, Canada
| | - Rami I Aqeilan
- The Concern Foundation Laboratories, The Lautenberg Center for Immunology and Cancer Research, Immunology and Cancer Research-IMRIC, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Peter L Carlen
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Ontario M5S 1A8, Canada; Krembil Research Institute, Division of Fundamental Neurobiology, Toronto Western Hospital, Toronto, Ontario M5T 0S8, Canada; Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 3G9, Canada; Department of Medicine (Neurology), University Health Network, Toronto, Ontario M5G 2C4, Canada
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42
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NRM 2021 Abstract Booklet. J Cereb Blood Flow Metab 2021; 41:11-309. [PMID: 34905986 PMCID: PMC8851538 DOI: 10.1177/0271678x211061050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Drysdale ND, Matthews E, Schuetz E, Pan E, McNamara JO. Intravenous kainic acid induces status epilepticus and late onset seizures in mice. Epilepsy Res 2021; 178:106816. [PMID: 34808484 DOI: 10.1016/j.eplepsyres.2021.106816] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 10/14/2021] [Accepted: 11/11/2021] [Indexed: 11/19/2022]
Abstract
We set out to establish a novel model of temporal lobe epilepsy (TLE) in a mouse. We sought to induce TLE through the injection of kainic acid (KA) into the tail vein with subsequent development of status epilepticus (SE). Using C57BL/6 mice, we implanted hippocampal EEG recording electrodes before or after injection of KA or phosphate buffered saline (PBS). Video and EEG analysis were conducted to evaluate for SE and development of recurrent seizures, the hallmark of TLE. All mice injected with KA developed SE while those who were injected with PBS did not. Of the animals injected with KA monitored for recurrent seizures following SE, 33% developed spontaneous recurrent seizures while those injected with PBS did not. Injection of KA through the tail vein of a mouse reliably and rapidly induces SE which remits spontaneously and leads to the development of TLE in a subset of mice.
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Affiliation(s)
| | | | | | | | - James O McNamara
- Department of Neurobiology, USA; Department of Neurology, USA; Department of Pharmacology and Molecular Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA.
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Deficits in Behavioral and Neuronal Pattern Separation in Temporal Lobe Epilepsy. J Neurosci 2021; 41:9669-9686. [PMID: 34620720 PMCID: PMC8612476 DOI: 10.1523/jneurosci.2439-20.2021] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 09/09/2021] [Accepted: 09/21/2021] [Indexed: 11/21/2022] Open
Abstract
In temporal lobe epilepsy, the ability of the dentate gyrus to limit excitatory cortical input to the hippocampus breaks down, leading to seizures. The dentate gyrus is also thought to help discriminate between similar memories by performing pattern separation, but whether epilepsy leads to a breakdown in this neural computation, and thus to mnemonic discrimination impairments, remains unknown. Here we show that temporal lobe epilepsy is characterized by behavioral deficits in mnemonic discrimination tasks, in both humans (females and males) and mice (C57Bl6 males, systemic low-dose kainate model). Using a recently developed assay in brain slices of the same epileptic mice, we reveal a decreased ability of the dentate gyrus to perform certain forms of pattern separation. This is because of a subset of granule cells with abnormal bursting that can develop independently of early EEG abnormalities. Overall, our results linking physiology, computation, and cognition in the same mice advance our understanding of episodic memory mechanisms and their dysfunction in epilepsy.SIGNIFICANCE STATEMENT People with temporal lobe epilepsy (TLE) often have learning and memory impairments, sometimes occurring earlier than the first seizure, but those symptoms and their biological underpinnings are poorly understood. We focused on the dentate gyrus, a brain region that is critical to avoid confusion between similar memories and is anatomically disorganized in TLE. We show that both humans and mice with TLE experience confusion between similar situations. This impairment coincides with a failure of the dentate gyrus to disambiguate similar input signals because of pathologic bursting in a subset of neurons. Our work bridges seizure-oriented and memory-oriented views of the dentate gyrus function, suggests a mechanism for cognitive symptoms in TLE, and supports a long-standing hypothesis of episodic memory theories.
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Vigier A, Partouche N, Michel FJ, Crépel V, Marissal T. Substantial outcome improvement using a refined pilocarpine mouse model of temporal lobe epilepsy. Neurobiol Dis 2021; 161:105547. [PMID: 34752924 DOI: 10.1016/j.nbd.2021.105547] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 09/20/2021] [Accepted: 11/02/2021] [Indexed: 11/25/2022] Open
Abstract
Systemic pilocarpine treatment is one of the most reliable means of inducing temporal lobe epilepsy (TLE). However, the traditional pilocarpine injection protocol using mice was associated with a high death rate, possibly because of cardiorespiratory collapse following status epilepticus (SE). To prevent this, we developed a modified procedure of pilocarpine SE induction, which included a single injection of a moderate dose of caffeine during the induction phase. That new protocol was based on the use of young male mice as well as on a refined Racine's scale. Using that protocol, we report a substantially increased survival rate, thus enabling the generation of a large cohort of mice that exhibited cardinal histological (e.g., mossy fiber sprouting) and electrophysiological (e.g., chronic interictal events and ictal seizures) characteristics associated with TLE. In conclusion, our refined caffeine- and pilocarpine-based protocol substantially improves the outcome of the reliable pilocarpine mouse model of TLE.
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Dubey V, Dey S, Dixit AB, Tripathi M, Chandra PS, Banerjee J. Differential glutamate receptor expression and function in the hippocampus, anterior temporal lobe and neocortex in a pilocarpine model of temporal lobe epilepsy. Exp Neurol 2021; 347:113916. [PMID: 34752784 DOI: 10.1016/j.expneurol.2021.113916] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 10/04/2021] [Accepted: 11/01/2021] [Indexed: 12/14/2022]
Abstract
Temporal lobe epilepsy (TLE) is the most common form of intractable epilepsy where hyperactive glutamate receptors may contribute to the complex epileptogenic network hubs distributed among different regions. This study was designed to investigate the region-specific molecular alterations of the glutamate receptors and associated excitatory synaptic transmission in pilocarpine rat model of TLE. We recorded spontaneous excitatory postsynaptic currents (EPSCs) from pyramidal neurons in resected rat brain slices of the hippocampus, anterior temporal lobe (ATL) and neocortex. We also performed mRNA and protein expression of the glutamate receptor subunits (NR1, NR2A, NR2B, and GLUR1-4) by qPCR and immunohistochemistry. We observed significant increase in the frequency and amplitude of spontaneous EPSCs in the hippocampal and ATL samples of TLE rats than in control rats. Additionally, the magnitude of the frequency and amplitude was increased in ATL samples compared to that of the hippocampal samples of TLE rats. The mRNA level of NR1 was upregulated in both the hippocampal as well as ATL samples and that of NR2A, NR2B were upregulated only in the hippocampal samples of TLE rats than in control rats. The mRNA level of GLUR4 was upregulated in both the hippocampal as well as ATL samples of TLE rats than in control rats. Immunohistochemical analysis demonstrated that the number of NR1, NR2A, NR2B, and GLUR4 immuno-positive cells were significantly higher in the hippocampal samples whereas number of NR1 and GLUR4 immuno-positive cells were significantly higher in the ATL samples of the TLE rats than in control rats. This study demonstrated the region-specific alterations of glutamate receptor subunits in pilocarpine model of TLE, suggesting possible cellular mechanisms contributing to generation of independent epileptogenic networks in different temporal lobe structures.
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Affiliation(s)
- Vivek Dubey
- Department of Biophysics, All India Institute of Medical Sciences, New Delhi, India
| | - Soumil Dey
- Department of Neurosurgery, All India Institute of Medical Sciences, New Delhi, India
| | | | - Manjari Tripathi
- Department of Neurology, All India Institute of Medical Sciences, New Delhi, India
| | - P Sarat Chandra
- Department of Neurosurgery, All India Institute of Medical Sciences, New Delhi, India
| | - Jyotirmoy Banerjee
- Department of Biophysics, All India Institute of Medical Sciences, New Delhi, India.
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Akyuz E, Koklu B, Uner A, Angelopoulou E, Paudel YN. Envisioning the role of inwardly rectifying potassium (Kir) channel in epilepsy. J Neurosci Res 2021; 100:413-443. [PMID: 34713909 DOI: 10.1002/jnr.24985] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2021] [Revised: 09/23/2021] [Accepted: 10/01/2021] [Indexed: 01/29/2023]
Abstract
Epilepsy is a devastating neurological disorder characterized by recurrent seizures attributed to the disruption of the dynamic excitatory and inhibitory balance in the brain. Epilepsy has emerged as a global health concern affecting about 70 million people worldwide. Despite recent advances in pre-clinical and clinical research, its etiopathogenesis remains obscure, and there are still no treatment strategies modifying disease progression. Although the precise molecular mechanisms underlying epileptogenesis have not been clarified yet, the role of ion channels as regulators of cellular excitability has increasingly gained attention. In this regard, emerging evidence highlights the potential implication of inwardly rectifying potassium (Kir) channels in epileptogenesis. Kir channels consist of seven different subfamilies (Kir1-Kir7), and they are highly expressed in both neuronal and glial cells in the central nervous system. These channels control the cell volume and excitability. In this review, we discuss preclinical and clinical evidence on the role of the several subfamilies of Kir channels in epileptogenesis, aiming to shed more light on the pathogenesis of this disorder and pave the way for future novel therapeutic approaches.
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Affiliation(s)
- Enes Akyuz
- Faculty of International Medicine, Department of Biophysics, University of Health Sciences, Istanbul, Turkey
| | - Betul Koklu
- Faculty of Medicine, Namık Kemal University, Tekirdağ, Turkey
| | - Arda Uner
- Faculty of Medicine, Yozgat Bozok University, Yozgat, Turkey
| | - Efthalia Angelopoulou
- Department of Biological Chemistry, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Yam Nath Paudel
- Neuropharmacology Research Strength, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Bandar Sunway, Malaysia
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Twible C, Abdo R, Zhang Q. Astrocyte Role in Temporal Lobe Epilepsy and Development of Mossy Fiber Sprouting. Front Cell Neurosci 2021; 15:725693. [PMID: 34658792 PMCID: PMC8514632 DOI: 10.3389/fncel.2021.725693] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 09/02/2021] [Indexed: 11/13/2022] Open
Abstract
Epilepsy affects approximately 50 million people worldwide, with 60% of adult epilepsies presenting an onset of focal origin. The most common focal epilepsy is temporal lobe epilepsy (TLE). The role of astrocytes in the presentation and development of TLE has been increasingly studied and discussed within the literature. The most common histopathological diagnosis of TLE is hippocampal sclerosis. Hippocampal sclerosis is characterized by neuronal cell loss within the Cornu ammonis and reactive astrogliosis. In some cases, mossy fiber sprouting may be observed. Mossy fiber sprouting has been controversial in its contribution to epileptogenesis in TLE patients, and the mechanisms surrounding the phenomenon have yet to be elucidated. Several studies have reported that mossy fiber sprouting has an almost certain co-existence with reactive astrogliosis within the hippocampus under epileptic conditions. Astrocytes are known to play an important role in the survival and axonal outgrowth of central and peripheral nervous system neurons, pointing to a potential role of astrocytes in TLE and associated cellular alterations. Herein, we review the recent developments surrounding the role of astrocytes in the pathogenic process of TLE and mossy fiber sprouting, with a focus on proposed signaling pathways and cellular mechanisms, histological observations, and clinical correlations in human patients.
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Affiliation(s)
- Carolyn Twible
- Department of Pathology and Lab Medicine, Western University, London, ON, Canada
| | - Rober Abdo
- Department of Pathology and Lab Medicine, Western University, London, ON, Canada.,Department of Anatomy and Cell Biology, Western University, London, ON, Canada
| | - Qi Zhang
- Department of Pathology and Lab Medicine, Western University, London, ON, Canada.,Department of Pathology and Lab Medicine, London Health Sciences Centre, University Hospital, London, ON, Canada
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Cheng L, Xing Y, Zhang H, Liu R, Lai H, Piao Y, Wang W, Yan X, Li X, Wang J, Li D, Loh HH, Yu T, Zhang G, Yang X. Mechanistic Analysis of Micro-Neurocircuits Underlying the Epileptogenic Zone in Focal Cortical Dysplasia Patients. Cereb Cortex 2021; 32:2216-2230. [PMID: 34664065 DOI: 10.1093/cercor/bhab350] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2021] [Revised: 08/22/2021] [Accepted: 08/23/2021] [Indexed: 11/13/2022] Open
Abstract
We aim to explore the microscopic neurophysiology of focal cortical dysplasia (FCD) induced epileptogenesis in specific macroscopic brain regions, therefore mapping a micro-macro neuronal network that potentially indicates the epileptogenic mechanism. Epileptic and relatively non-epileptic temporal neocortex specimens were resected from FCD and mesial temporal lobe epilepsy (mTLE) patients, respectively. Whole-cell patch-clamping was performed on cells from the seizure onset zone (SOZ) and non-SOZ inside the epileptogenic zone (EZ) of FCD patients, as well as the non-epileptic neocortex of mTLE patients. Microscopic data were recorded, including membrane characteristics, spontaneous synaptic activities, and evoked action potentials. Immunohistochemistry was also performed on parvalbumin-positive (PV+) interneurons. We found that SOZ interneurons exhibited abnormal neuronal expression and distribution as well as reduced overall function compared with non-SOZ and mTLE interneurons. The SOZ pyramidal cells experienced higher excitation but lower inhibition than the mTLE controls, whereas the non-SOZ pyramidal cells exhibited intermediate excitability. Action potential properties of both types of neurons also suggested more synchronized neuronal activity inside the EZ, particularly inside the SOZ. Together, our research provides evidence for a potential neurocircuit underlying SOZ epileptogenesis and non-SOZ seizure susceptibility. Further investigation of this microscopic network may promote understanding of the mechanism of FCD-induced epileptogenesis.
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Affiliation(s)
- Lipeng Cheng
- Center of Epilepsy, Beijing Institute of Brain Disorders, Capital Medical University, Beijing 100069, China.,Fundamental Research Department, Guangzhou Laboratory, Guangzhou 510700, China.,Neuroelectrophysiological Laboratory, Xuanwu Hospital, Capital Medical University, Beijing 100053, China
| | - Yue Xing
- Center of Epilepsy, Beijing Institute of Brain Disorders, Capital Medical University, Beijing 100069, China.,Fundamental Research Department, Guangzhou Laboratory, Guangzhou 510700, China.,Neuroelectrophysiological Laboratory, Xuanwu Hospital, Capital Medical University, Beijing 100053, China
| | - Herui Zhang
- Fundamental Research Department, Guangzhou Laboratory, Guangzhou 510700, China
| | - Ru Liu
- Center of Epilepsy, Beijing Institute of Brain Disorders, Capital Medical University, Beijing 100069, China.,Fundamental Research Department, Guangzhou Laboratory, Guangzhou 510700, China.,Neuroelectrophysiological Laboratory, Xuanwu Hospital, Capital Medical University, Beijing 100053, China
| | - Huanling Lai
- Fundamental Research Department, Guangzhou Laboratory, Guangzhou 510700, China
| | - Yueshan Piao
- Department of Pathology, Xuanwu Hospital, Capital Medical University, Beijing 100053, China
| | - Wei Wang
- Center of Epilepsy, Beijing Institute of Brain Disorders, Capital Medical University, Beijing 100069, China.,Fundamental Research Department, Guangzhou Laboratory, Guangzhou 510700, China.,Neuroelectrophysiological Laboratory, Xuanwu Hospital, Capital Medical University, Beijing 100053, China
| | - Xiaoming Yan
- Department of Functional Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing 100053, China
| | - Xiaonan Li
- Center of Epilepsy, Beijing Institute of Brain Disorders, Capital Medical University, Beijing 100069, China.,Fundamental Research Department, Guangzhou Laboratory, Guangzhou 510700, China.,Neuroelectrophysiological Laboratory, Xuanwu Hospital, Capital Medical University, Beijing 100053, China
| | - Jiaoyang Wang
- Center of Epilepsy, Beijing Institute of Brain Disorders, Capital Medical University, Beijing 100069, China.,Fundamental Research Department, Guangzhou Laboratory, Guangzhou 510700, China.,Neuroelectrophysiological Laboratory, Xuanwu Hospital, Capital Medical University, Beijing 100053, China
| | - Donghong Li
- Center of Epilepsy, Beijing Institute of Brain Disorders, Capital Medical University, Beijing 100069, China.,Fundamental Research Department, Guangzhou Laboratory, Guangzhou 510700, China.,Neuroelectrophysiological Laboratory, Xuanwu Hospital, Capital Medical University, Beijing 100053, China.,Department of Neurology, The Third Affiliated Hospital of Sun Yat-sen University, Guangdong 510635, China
| | - Horace H Loh
- Fundamental Research Department, Guangzhou Laboratory, Guangzhou 510700, China
| | - Tao Yu
- Department of Functional Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing 100053, China
| | - Guojun Zhang
- Department of Functional Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing 100053, China.,Functional Neurosurgery Department, Beijing Children's Hospital, Capital Medical University, Beijing 100045, China
| | - Xiaofeng Yang
- Center of Epilepsy, Beijing Institute of Brain Disorders, Capital Medical University, Beijing 100069, China.,Fundamental Research Department, Guangzhou Laboratory, Guangzhou 510700, China.,Neuroelectrophysiological Laboratory, Xuanwu Hospital, Capital Medical University, Beijing 100053, China
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Characterization of metabolic activity induced by kainic acid in adult rat whole brain at the early stage: A 18FDG-PET study. Brain Res 2021; 1769:147621. [PMID: 34403661 DOI: 10.1016/j.brainres.2021.147621] [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: 04/21/2021] [Revised: 07/08/2021] [Accepted: 08/10/2021] [Indexed: 11/23/2022]
Abstract
OBJECTIVE Brain metabolic processes are not fully characterized in the kainic acid (KA)-induced Status Epilepticus (KASE). Thus, we evaluated the usefulness of 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) as an experimental strategy to evaluate in vivo, in a non-invasive way, the glucose consumption in several brain regions, in a semi-quantitative study to compare and to correlate with data from electroencephalography and histology studies. METHODS Sixteen male Wistar rats underwent FDG-PET scans at basal state and after KA injection. FDG-PET images were normalized to an MRI-based atlas and segmented to locate regions. Standardized uptake values (SUV) were obtained at several time points. EEGs and cell viability by histological analysis, were also evaluated. RESULTS FDG-PET data showed changes in regions such as: amygdala, hippocampus, accumbens, entorhinal cortex, motor cortex and hypothalamus. Remarkably, hippocampal hypermetabolism was found (mean SUV = 2.66 ± 0.057) 2 h after KA administration, while hypometabolism at 24 h (mean SUV = 1.83 ± 0.056) vs basal values (mean SUV = 2.19 ± 0.057). EEG showed increased spectral power values 2 h post-KA administration. Hippocampal viable-cell counting 24 h after KA was decreased, while Fluoro-Jade B-positive cells were increased, as compared to control rats, coinciding with the hypometabolism detected in the same region by semi-quantitative FDG-PET at 24 h after KASE. CONCLUSIONS PET is suitable to measure metabolic brain changes in the rat model of status epilepticus induced by KA (KASE) at the first 24 h, compared to that of EEG; PET data may also be sensitive to cell viability.
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