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Colmers PLW, Arshad MN, Mukherjee J, Lin S, Ng SFJ, Sarmiere P, Davies PA, Moss SJ. Sustained Inhibition of GABA-AT by OV329 Enhances Neuronal Inhibition and Prevents Development of Benzodiazepine Refractory Seizures. eNeuro 2024; 11:ENEURO.0137-24.2024. [PMID: 38937107 PMCID: PMC11236575 DOI: 10.1523/eneuro.0137-24.2024] [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: 03/28/2024] [Revised: 06/18/2024] [Accepted: 06/24/2024] [Indexed: 06/29/2024] Open
Abstract
γ-Aminobutyric acid (GABA) is the principal inhibitory neurotransmitter in the adult brain which mediates its rapid effects on neuronal excitability via ionotropic GABAA receptors. GABA levels in the brain are critically dependent upon GABA-aminotransferase (GABA-AT) which promotes its degradation. Vigabatrin, a low-affinity GABA-AT inhibitor, exhibits anticonvulsant efficacy, but its use is limited due to cumulative ocular toxicity. OV329 is a rationally designed, next-generation GABA-AT inhibitor with enhanced potency. We demonstrate that sustained exposure to OV329 in mice reduces GABA-AT activity and subsequently elevates GABA levels in the brain. Parallel increases in the efficacy of GABAergic inhibition were evident, together with elevations in electroencephalographic delta power. Consistent with this, OV329 exposure reduced the severity of status epilepticus and the development of benzodiazepine refractory seizures. Thus, OV329 may be of utility in treating seizure disorders and associated pathologies that result from neuronal hyperexcitability.
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Affiliation(s)
- Phillip L W Colmers
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts 02111
| | - Muhammad Nauman Arshad
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts 02111
| | | | | | - Shu Fun Josephine Ng
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts 02111
| | | | - Paul A Davies
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts 02111
| | - Stephen J Moss
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts 02111
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1 6BT, United Kingdom
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2
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Rodriguez S, Sharma S, Tiarks G, Peterson Z, Jackson K, Thedens D, Wong A, Keffala-Gerhard D, Mahajan VB, Ferguson PJ, Newell EA, Glykys J, Nickl-Jockschat T, Bassuk AG. Neuroprotective effects of naltrexone in a mouse model of post-traumatic seizures. Sci Rep 2024; 14:13507. [PMID: 38867062 PMCID: PMC11169394 DOI: 10.1038/s41598-024-63942-8] [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: 01/30/2024] [Accepted: 06/03/2024] [Indexed: 06/14/2024] Open
Abstract
Traumatic Brain Injury (TBI) induces neuroinflammatory response that can initiate epileptogenesis, which develops into epilepsy. Recently, we identified anti-convulsive effects of naltrexone, a mu-opioid receptor (MOR) antagonist, used to treat drug addiction. While blocking opioid receptors can reduce inflammation, it is unclear if post-TBI seizures can be prevented by blocking MORs. Here, we tested if naltrexone prevents neuroinflammation and/or seizures post-TBI. TBI was induced by a modified Marmarou Weight-Drop (WD) method on 4-week-old C57BL/6J male mice. Mice were placed in two groups: non-telemetry assessing the acute effects or in telemetry monitoring for interictal events and spontaneous seizures both following TBI and naltrexone. Molecular, histological and neuroimaging techniques were used to evaluate neuroinflammation, neurodegeneration and fiber track integrity at 8 days and 3 months post-TBI. Peripheral immune responses were assessed through serum chemokine/cytokine measurements. Our results show an increase in MOR expression, nitro-oxidative stress, mRNA expression of inflammatory cytokines, microgliosis, neurodegeneration, and white matter damage in the neocortex of TBI mice. Video-EEG revealed increased interictal events in TBI mice, with 71% mice developing post-traumatic seizures (PTS). Naltrexone treatment ameliorated neuroinflammation, neurodegeneration, reduced interictal events and prevented seizures in all TBI mice, which makes naltrexone a promising candidate against PTS, TBI-associated neuroinflammation and epileptogenesis in a WD model of TBI.
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Affiliation(s)
- Saul Rodriguez
- Stead Family Department of Pediatrics , Carver College of Medicine, University of Iowa, 25 South Grand Ave, 2040 MedLabs, Iowa City, IA, 52242, USA
| | - Shaunik Sharma
- Stead Family Department of Pediatrics , Carver College of Medicine, University of Iowa, 25 South Grand Ave, 2040 MedLabs, Iowa City, IA, 52242, USA
| | - Grant Tiarks
- Stead Family Department of Pediatrics , Carver College of Medicine, University of Iowa, 25 South Grand Ave, 2040 MedLabs, Iowa City, IA, 52242, USA
| | - Zeru Peterson
- Department of Psychiatry, University of Iowa, Iowa City, IA, USA
| | - Kyle Jackson
- Stead Family Department of Pediatrics , Carver College of Medicine, University of Iowa, 25 South Grand Ave, 2040 MedLabs, Iowa City, IA, 52242, USA
| | - Daniel Thedens
- Department of Radiology, University of Iowa, Iowa City, IA, USA
| | - Angela Wong
- Stead Family Department of Pediatrics , Carver College of Medicine, University of Iowa, 25 South Grand Ave, 2040 MedLabs, Iowa City, IA, 52242, USA
| | - David Keffala-Gerhard
- Stead Family Department of Pediatrics , Carver College of Medicine, University of Iowa, 25 South Grand Ave, 2040 MedLabs, Iowa City, IA, 52242, USA
| | - Vinit B Mahajan
- Department of Ophthalmology, Stanford University, Palo Alto, CA, USA
| | - Polly J Ferguson
- Stead Family Department of Pediatrics , Carver College of Medicine, University of Iowa, 25 South Grand Ave, 2040 MedLabs, Iowa City, IA, 52242, USA
| | - Elizabeth A Newell
- Stead Family Department of Pediatrics , Carver College of Medicine, University of Iowa, 25 South Grand Ave, 2040 MedLabs, Iowa City, IA, 52242, USA
| | - Joseph Glykys
- Stead Family Department of Pediatrics , Carver College of Medicine, University of Iowa, 25 South Grand Ave, 2040 MedLabs, Iowa City, IA, 52242, USA
- Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, USA
- Department of Neurology, University of Iowa, Iowa City, IA, USA
| | - Thomas Nickl-Jockschat
- Department of Psychiatry, University of Iowa, Iowa City, IA, USA
- Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, USA
- Department of Psychiatry and Psychotherapy, Otto-von-Guericke University, Magdeburg, Germany German Center for Mental Health (DZPG), partner site Halle-Jena-Magdeburg, Germany Center for Intervention and Research on adaptive and maladaptive brain Circuits underlying mental health (C-I-R-C), Halle-Jena-Magdeburg, Germany
| | - Alexander G Bassuk
- Stead Family Department of Pediatrics , Carver College of Medicine, University of Iowa, 25 South Grand Ave, 2040 MedLabs, Iowa City, IA, 52242, USA.
- Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, USA.
- Department of Neurology, University of Iowa, Iowa City, IA, USA.
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3
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Liu Z, Deng C, Zhou Z, Xiao Y, Jiang S, Zhu B, Naler LB, Jia X, Yao DD, Lu C. Epigenomic tomography for probing spatially defined chromatin state in the brain. CELL REPORTS METHODS 2024; 4:100738. [PMID: 38508188 PMCID: PMC10985265 DOI: 10.1016/j.crmeth.2024.100738] [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: 04/24/2023] [Revised: 12/24/2023] [Accepted: 02/27/2024] [Indexed: 03/22/2024]
Abstract
Spatially resolved epigenomic profiling is critical for understanding biology in the mammalian brain. Single-cell spatial epigenomic assays were developed recently for this purpose, but they remain costly and labor intensive for examining brain tissues across substantial dimensions and surveying a collection of brain samples. Here, we demonstrate an approach, epigenomic tomography, that maps spatial epigenomes of mouse brain at the scale of centimeters. We individually profiled neuronal and glial fractions of mouse neocortex slices with 0.5 mm thickness. Tri-methylation of histone 3 at lysine 27 (H3K27me3) or acetylation of histone 3 at lysine 27 (H3K27ac) features across these slices were grouped into clusters based on their spatial variation patterns to form epigenomic brain maps. As a proof of principle, our approach reveals striking dynamics in the frontal cortex due to kainic-acid-induced seizure, linked with transmembrane ion transporters, exocytosis of synaptic vesicles, and secretion of neurotransmitters. Epigenomic tomography provides a powerful and cost-effective tool for characterizing brain disorders based on the spatial epigenome.
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Affiliation(s)
- Zhengzhi Liu
- Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, VA, USA
| | - Chengyu Deng
- Department of Chemical Engineering, Virginia Tech, Blacksburg, VA, USA
| | - Zirui Zhou
- Department of Chemical Engineering, Virginia Tech, Blacksburg, VA, USA
| | - Ya Xiao
- Department of Computer Science, Virginia Tech, Blacksburg, VA, USA
| | - Shan Jiang
- Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, VA, USA
| | - Bohan Zhu
- Department of Chemical Engineering, Virginia Tech, Blacksburg, VA, USA
| | - Lynette B Naler
- Department of Chemical Engineering, Virginia Tech, Blacksburg, VA, USA
| | - Xiaoting Jia
- Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, VA, USA
| | | | - Chang Lu
- Department of Chemical Engineering, Virginia Tech, Blacksburg, VA, USA.
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Chen F, Dong X, Wang Z, Wu T, Wei L, Li Y, Zhang K, Ma Z, Tian C, Li J, Zhao J, Zhang W, Liu A, Shen H. Regulation of specific abnormal calcium signals in the hippocampal CA1 and primary cortex M1 alleviates the progression of temporal lobe epilepsy. Neural Regen Res 2024; 19:425-433. [PMID: 37488907 PMCID: PMC10503629 DOI: 10.4103/1673-5374.379048] [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: 02/06/2023] [Revised: 03/15/2023] [Accepted: 05/04/2023] [Indexed: 07/26/2023] Open
Abstract
Temporal lobe epilepsy is a multifactorial neurological dysfunction syndrome that is refractory, resistant to antiepileptic drugs, and has a high recurrence rate. The pathogenesis of temporal lobe epilepsy is complex and is not fully understood. Intracellular calcium dynamics have been implicated in temporal lobe epilepsy. However, the effect of fluctuating calcium activity in CA1 pyramidal neurons on temporal lobe epilepsy is unknown, and no longitudinal studies have investigated calcium activity in pyramidal neurons in the hippocampal CA1 and primary motor cortex M1 of freely moving mice. In this study, we used a multi-channel fiber photometry system to continuously record calcium signals in CA1 and M1 during the temporal lobe epilepsy process. We found that calcium signals varied according to the grade of temporal lobe epilepsy episodes. In particular, cortical spreading depression, which has recently been frequently used to represent the continuously and substantially increased calcium signals, was found to correspond to complex and severe behavioral characteristics of temporal lobe epilepsy ranging from grade II to grade V. However, vigorous calcium oscillations and highly synchronized calcium signals in CA1 and M1 were strongly related to convulsive motor seizures. Chemogenetic inhibition of pyramidal neurons in CA1 significantly attenuated the amplitudes of the calcium signals corresponding to grade I episodes. In addition, the latency of cortical spreading depression was prolonged, and the above-mentioned abnormal calcium signals in CA1 and M1 were also significantly reduced. Intriguingly, it was possible to rescue the altered intracellular calcium dynamics. Via simultaneous analysis of calcium signals and epileptic behaviors, we found that the progression of temporal lobe epilepsy was alleviated when specific calcium signals were reduced, and that the end-point behaviors of temporal lobe epilepsy were improved. Our results indicate that the calcium dynamic between CA1 and M1 may reflect specific epileptic behaviors corresponding to different grades. Furthermore, the selective regulation of abnormal calcium signals in CA1 pyramidal neurons appears to effectively alleviate temporal lobe epilepsy, thereby providing a potential molecular mechanism for a new temporal lobe epilepsy diagnosis and treatment strategy.
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Affiliation(s)
- Feng Chen
- Laboratory of Neurobiology, School of Biomedical Engineering, Tianjin Medical University, Tianjin, China
- Institute for Translational Neuroscience, the Second Affiliated Hospital of Nantong University, Nantong, Jiangsu Province, China
| | - Xi Dong
- Laboratory of Neurobiology, School of Biomedical Engineering, Tianjin Medical University, Tianjin, China
- Institute for Translational Brain Research, Fudan University, Shanghai, China
| | - Zhenhuan Wang
- Laboratory of Neurobiology, School of Biomedical Engineering, Tianjin Medical University, Tianjin, China
| | - Tongrui Wu
- Laboratory of Neurobiology, School of Biomedical Engineering, Tianjin Medical University, Tianjin, China
| | - Liangpeng Wei
- Laboratory of Neurobiology, School of Biomedical Engineering, Tianjin Medical University, Tianjin, China
- Department of Radiology, the Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, Jiangsu Province, China
| | - Yuanyuan Li
- Innovative Institute of Chinese Medicine and Pharmacy, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Kai Zhang
- Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin, China
| | - Zengguang Ma
- Laboratory of Neurobiology, School of Biomedical Engineering, Tianjin Medical University, Tianjin, China
| | - Chao Tian
- Laboratory of Neurobiology, School of Biomedical Engineering, Tianjin Medical University, Tianjin, China
| | - Jing Li
- Department of Orthopaedics, Tianjin Medical University General Hospital, Tianjin, China
| | - Jingyu Zhao
- Laboratory of Neurobiology, School of Biomedical Engineering, Tianjin Medical University, Tianjin, China
| | - Wei Zhang
- Tianjin Eye Hospital, Tianjin Eye Institute, Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin, China
| | - Aili Liu
- Laboratory of Neurobiology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China
| | - Hui Shen
- Innovative Institute of Chinese Medicine and Pharmacy, Shandong University of Traditional Chinese Medicine, Jinan, China
- Laboratory of Neurobiology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China
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Lawande NV, Conklin EA, Christian‐Hinman CA. Sex and gonadectomy modify behavioral seizure susceptibility and mortality in a repeated low-dose kainic acid systemic injection paradigm in mice. Epilepsia Open 2023; 8:1512-1522. [PMID: 37715318 PMCID: PMC10690657 DOI: 10.1002/epi4.12828] [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: 08/02/2023] [Accepted: 09/12/2023] [Indexed: 09/17/2023] Open
Abstract
OBJECTIVE Sex differences in epilepsy appear driven in part due to effects of gonadal steroids, with varying results in experimental models based on species, strain, and method of seizure induction. Furthermore, removing the main source of these steroids via gonadectomy may impact seizure characteristics differently in males and females. Repeated low-dose kainic acid (RLDKA) systemic injection paradigms were recently shown to reliably induce status epilepticus (SE) and hippocampal histopathology in C57BL/6J mice. Here, we investigated whether seizure susceptibility in a RLDKA injection protocol exhibits a sex difference and whether gonadectomy differentially influences response to this seizure induction paradigm in males and females. METHODS Adult C57BL/6J mice were left gonad-intact as controls or gonadectomized (females: ovariectomized, OVX; males: orchidectomized, ORX). At least 2 weeks later, KA was injected ip, every 30 minutes at 7.5 mg/kg or less until the animal reached SE, defined by at least 5 generalized seizures (GS, Racine stage 3 or higher). Parameters of susceptibility to GS induction, SE development, and mortality rates were quantified. RESULTS No differences in seizure susceptibility or mortality were observed between control males and control females. Gonadectomized mice exhibited increased susceptibility and reduced latency to both GS and SE in comparison to corresponding controls of the same sex, but the effects were stronger in males. In addition, ORX males, but not OVX females, exhibited strongly increased seizure-induced mortality. SIGNIFICANCE The RLDKA protocol is notable for its efficacy in inducing SE and seizure-induced histopathology in C57BL/6J mice, the background for many transgenic strains in current use in epilepsy research. The present results indicate that this protocol may be beneficial for investigating the effects of gonadal hormone replacement on seizure susceptibility, mortality, and seizure-induced histopathology, and that gonadectomy unmasks sex differences in susceptibility to seizures and mortality not observed in gonad-intact controls.
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Affiliation(s)
- Niraj V. Lawande
- Department of Molecular and Integrative PhysiologyUniversity of Illinois Urbana‐ChampaignUrbanaIllinoisUSA
| | | | - Catherine A. Christian‐Hinman
- Department of Molecular and Integrative PhysiologyUniversity of Illinois Urbana‐ChampaignUrbanaIllinoisUSA
- Neuroscience ProgramUniversity of Illinois Urbana‐ChampaignUrbanaIllinoisUSA
- Beckman Institute for Advanced Science and TechnologyUniversity of Illinois Urbana‐ChampaignUrbanaIllinoisUSA
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McGann AM, Westerkamp GC, Chalasani A, Danzer CSK, Parkins EV, Rajathi V, Horn PS, Pedapati EV, Tiwari D, Danzer SC, Gross C. MiR-324-5p inhibition after intrahippocampal kainic acid-induced status epilepticus does not prevent epileptogenesis in mice. Front Neurol 2023; 14:1280606. [PMID: 38033777 PMCID: PMC10687438 DOI: 10.3389/fneur.2023.1280606] [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: 08/20/2023] [Accepted: 10/20/2023] [Indexed: 12/02/2023] Open
Abstract
Background Acquired epilepsies are caused by an initial brain insult that is followed by epileptogenesis and finally the development of spontaneous recurrent seizures. The mechanisms underlying epileptogenesis are not fully understood. MicroRNAs regulate mRNA translation and stability and are frequently implicated in epilepsy. For example, antagonism of a specific microRNA, miR-324-5p, before brain insult and in a model of chronic epilepsy decreases seizure susceptibility and frequency, respectively. Here, we tested whether antagonism of miR-324-5p during epileptogenesis inhibits the development of epilepsy. Methods We used the intrahippocampal kainic acid (IHpKa) model to initiate epileptogenesis in male wild type C57BL/6 J mice aged 6-8 weeks. Twenty-four hours after IHpKa, we administered a miR-324-5p or scrambled control antagomir intracerebroventricularly and implanted cortical surface electrodes for EEG monitoring. EEG data was collected for 28 days and analyzed for seizure frequency and duration, interictal spike activity, and EEG power. Brains were collected for histological analysis. Results Histological analysis of brain tissue showed that IHpKa caused characteristic hippocampal damage in most mice regardless of treatment. Antagomir treatment did not affect latency to, frequency, or duration of spontaneous recurrent seizures or interictal spike activity but did alter the temporal development of frequency band-specific EEG power. Conclusion These results suggest that miR-324-5p inhibition during epileptogenesis induced by status epilepticus does not convey anti-epileptogenic effects despite having subtle effects on EEG frequency bands. Our results highlight the importance of timing of intervention across epilepsy development and suggest that miR-324-5p may act primarily as a proconvulsant rather than a pro-epileptogenic regulator.
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Affiliation(s)
- Amanda M. McGann
- Medical Scientist Training Program, University of Cincinnati College of Medicine, Cincinnati, OH, United States
- Neuroscience Graduate Program, University of Cincinnati College of Medicine, Cincinnati, OH, United States
- Division of Neurology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, United States
| | - Grace C. Westerkamp
- Division of Child and Adolescent Psychiatry, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, United States
| | - Alisha Chalasani
- Division of Neurology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, United States
| | - Cole S. K. Danzer
- Division of Neurology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, United States
| | - Emma V. Parkins
- Neuroscience Graduate Program, University of Cincinnati College of Medicine, Cincinnati, OH, United States
- Division of Neurology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, United States
| | - Valerine Rajathi
- Division of Neurology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, United States
| | - Paul S. Horn
- Division of Neurology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, United States
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Ernest V. Pedapati
- Division of Neurology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, United States
- Division of Child and Adolescent Psychiatry, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, United States
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Durgesh Tiwari
- Division of Neurology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, United States
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Steve C. Danzer
- Medical Scientist Training Program, University of Cincinnati College of Medicine, Cincinnati, OH, United States
- Neuroscience Graduate Program, University of Cincinnati College of Medicine, Cincinnati, OH, United States
- Division of Anesthesia, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, United States
- Department of Anesthesia, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Christina Gross
- Medical Scientist Training Program, University of Cincinnati College of Medicine, Cincinnati, OH, United States
- Neuroscience Graduate Program, University of Cincinnati College of Medicine, Cincinnati, OH, United States
- Division of Neurology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, United States
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, United States
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Rao NS, Putra M, Meyer C, Almanza A, Thippeswamy T. The effects of Src tyrosine kinase inhibitor, saracatinib, on the markers of epileptogenesis in a mixed-sex cohort of adult rats in the kainic acid model of epilepsy. Front Mol Neurosci 2023; 16:1294514. [PMID: 38025259 PMCID: PMC10665569 DOI: 10.3389/fnmol.2023.1294514] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Accepted: 10/25/2023] [Indexed: 12/01/2023] Open
Abstract
Neurodegeneration and neuroinflammation are key processes of epileptogenesis in temporal lobe epilepsy (TLE). A considerable number (∼30%) of patients with epilepsy are resistant to currently available antiseizure drugs and thus there is a need to develop adjunct therapies to modify disease progression. A vast majority of interventional strategies to treat TLE have utilized males which limits the translational nature of the studies. In this study, we investigated the effects of repeated low-dose kainic acid (KA) injection on the initial status epilepticus (SE) and the effects of Src kinase inhibitor, saracatinib (SAR/AZD0530; 20 mg/kg, oral, daily for 7 days), in a mixed-sex cohort of adult Sprague Dawley rats during early epileptogenesis. There were no sex differences in response to KA-induced SE, and neither did the stage of estrus influence SE severity. KA-induced SE caused significant astrogliosis and microgliosis across the hippocampus, piriform cortex, and amygdala. SAR treatment resulted in a significant reduction of microgliosis across brain regions. Microglial morphometrics such as branch length and the endpoints strongly correlated with CD68 expression in the vehicle-treated group but not in the SAR-treated group, indicating mitigation by SAR. KA-induced SE caused significant neuronal loss, including parvalbumin-positive inhibitory neurons, in both vehicle (VEH) and SAR-treated groups. SAR treatment significantly mitigated FJB-positive neuronal counts as compared to the VEH group. There was an increase in C3-positive reactive astrocytes in the VEH-treated group, and SAR treatment significantly reduced the increase in the piriform cortex. C3-positive astrogliosis significantly correlated with CD68 expression in the amygdala (AMY) of VEH-treated rats, and SAR treatment mitigated this relationship. There was a significant increase of pSrc(Y419)-positive microglia in both KA-treated groups with a statistically insignificant reduction by SAR. KA-induced SE caused the development of classical glial scars in the piriform cortex (PIR) in both KA-treated groups, while SAR treatment led to a 42.17% reduction in the size of glial scars. We did not observe sex differences in any of the parameters in this study. SAR, at the dose tested in the rat kainate model for a week in this study mitigated some of the markers of epileptogenesis in both sexes.
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Affiliation(s)
| | | | | | | | - Thimmasettappa Thippeswamy
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, United States
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Chen C, Zhu T, Gong L, Hu Z, Wei H, Fan J, Lin D, Wang X, Xu J, Dong X, Wang Y, Xia N, Zeng L, Jiang P, Xie Y. Trpm2 deficiency in microglia attenuates neuroinflammation during epileptogenesis by upregulating autophagy via the AMPK/mTOR pathway. Neurobiol Dis 2023; 186:106273. [PMID: 37648036 DOI: 10.1016/j.nbd.2023.106273] [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: 05/19/2023] [Revised: 08/15/2023] [Accepted: 08/27/2023] [Indexed: 09/01/2023] Open
Abstract
Epilepsy is one of the most common neurological disorders. Neuroinflammation involving the activation of microglia and astrocytes constitutes an important and common mechanism in epileptogenesis. Transient receptor potential melastatin 2 (TRPM2) is a calcium-permeable, non-selective cation channel that plays pathological roles in various inflammation-related diseases. Our previous study demonstrated that Trpm2 knockout exhibits therapeutic effects on pilocarpine-induced glial activation and neuroinflammation. However, whether TRPM2 in microglia and astrocytes plays a common pathogenic role in this process and the underlying molecular mechanisms remained undetermined. Here, we demonstrate a previously unknown role for microglial TRPM2 in epileptogenesis. Trpm2 knockout in microglia attenuated kainic acid (KA)-induced glial activation, inflammatory cytokines production and hippocampal paroxysmal discharges, whereas Trpm2 knockout in astrocytes exhibited no significant effects. Furthermore, we discovered that these therapeutic effects were mediated by upregulated autophagy via the adenosine monophosphate activated protein kinase (AMPK)/mammalian target of rapamycin (mTOR) pathway in microglia. Thus, our findings highlight an important deleterious role of microglial TRPM2 in temporal lobe epilepsy.
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Affiliation(s)
- Chen Chen
- Department of Neurology, Department of Neurobiology and Department of Rehabilitation, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center For Child Health, Hangzhou 310052, China
| | - Tao Zhu
- Department of Critical Care Medicine, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou 310030, China
| | - Lifen Gong
- Department of Neurology, Department of Neurobiology and Department of Rehabilitation, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center For Child Health, Hangzhou 310052, China
| | - Zhe Hu
- Department of Neurology, Department of Neurobiology and Department of Rehabilitation, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center For Child Health, Hangzhou 310052, China
| | - Hao Wei
- Department of Pharmacy, Xuzhou Medical University, 221004 Xuzhou, China
| | - Jianchen Fan
- Key Laboratory of Novel Targets and Drug Study for Neural Repair of Zhejiang Province, School of Medicine, Hangzhou City University, Hangzhou 310015, China
| | - Donghui Lin
- Department of Neurology, Department of Neurobiology and Department of Rehabilitation, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center For Child Health, Hangzhou 310052, China
| | - Xiaojun Wang
- Department of Neurology, Department of Neurobiology and Department of Rehabilitation, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center For Child Health, Hangzhou 310052, China
| | - Junyu Xu
- Department of Neurology, Department of Neurobiology and Department of Rehabilitation, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center For Child Health, Hangzhou 310052, China
| | - Xinyan Dong
- Department of Neurology, Department of Neurobiology and Department of Rehabilitation, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center For Child Health, Hangzhou 310052, China
| | - Yifan Wang
- Department of Neurology, Department of Neurobiology and Department of Rehabilitation, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center For Child Health, Hangzhou 310052, China
| | - Ningxiao Xia
- Department of Neurology, Department of Neurobiology and Department of Rehabilitation, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center For Child Health, Hangzhou 310052, China
| | - Linghui Zeng
- Key Laboratory of Novel Targets and Drug Study for Neural Repair of Zhejiang Province, School of Medicine, Hangzhou City University, Hangzhou 310015, China
| | - Peifang Jiang
- Department of Neurology, Department of Neurobiology and Department of Rehabilitation, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center For Child Health, Hangzhou 310052, China.
| | - Yicheng Xie
- Department of Neurology, Department of Neurobiology and Department of Rehabilitation, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center For Child Health, Hangzhou 310052, China.
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Lawande NV, Conklin EA, Christian-Hinman CA. Sex and gonadectomy modify behavioral seizure susceptibility and mortality in a repeated low-dose kainic acid systemic injection paradigm in mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.22.541824. [PMID: 37292790 PMCID: PMC10245840 DOI: 10.1101/2023.05.22.541824] [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
Objective Sex differences in epilepsy appear driven in part due to effects of gonadal steroids, with varying results in experimental models based on species, strain, and method of seizure induction. Furthermore, removing a main source of these steroids via gonadectomy may impact seizure characteristics differently in males and females. Repeated low-dose kainic acid (RLDKA) systemic injection paradigms were recently shown to reliably induce status epilepticus (SE) and hippocampal histopathology in C57BL/6J mice. Here, we investigated whether seizure susceptibility in a RLDKA injection protocol exhibits a sex difference, and whether gonadectomy differentially influences response to this seizure induction paradigm in males and females. Methods Adult C57BL/6J mice were left gonad-intact as controls or gonadectomized (females: ovariectomized, OVX; males: orchidectomized, ORX). At least 2 weeks later, KA was injected i.p. every 30 minutes at 7.5 mg/kg or less until the animal reached SE, defined by at least 5 generalized seizures (GS, Racine stage 3 or higher). Parameters of susceptibility to GS induction, SE development, and mortality rates were quantified. Results No differences in seizure susceptibility or mortality were observed between control males and control females. ORX males exhibited increased susceptibility and reduced latency to both GS and SE, but OVX females exhibited increased susceptibility and reduced latency to SE only. However, ORX males, but not OVX females, exhibited strongly increased seizure-induced mortality. Significance The RLDKA protocol is notable for its efficacy in inducing SE and seizure-induced histopathology in C57BL/6J mice, the background for many transgenic strains in current use in epilepsy research. The present results indicate that this protocol may be beneficial for investigating the effects of gonadal hormone replacement on seizure susceptibility, mortality, and seizure-induced histopathology, and that gonadectomy unmasks sex differences in susceptibility to seizures and mortality not observed in gonad-intact controls.
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Affiliation(s)
- Niraj V. Lawande
- Department of Molecular and Integrative Physiology, University of Illinois Urbana-Champaign, Urbana, IL, 61801 USA
| | - Elisabeth A. Conklin
- Neuroscience Program, University of Illinois Urbana-Champaign, Urbana, IL, 61801 USA
| | - Catherine A. Christian-Hinman
- Department of Molecular and Integrative Physiology, University of Illinois Urbana-Champaign, Urbana, IL, 61801 USA
- Neuroscience Program, University of Illinois Urbana-Champaign, Urbana, IL, 61801 USA
- Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, Urbana, IL, 61801 USA
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10
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Vasanthi SS, Rao NS, Samidurai M, Massey N, Meyer C, Gage M, Kharate M, Almanza A, Wachter L, Mafuta C, Trevino L, Carlo AM, Bryant E, Corson BE, Wohlgemuth M, Ostrander M, Showman L, Wang C, Thippeswamy T. Disease-modifying effects of a glial-targeted inducible nitric oxide synthase inhibitor (1400W) in mixed-sex cohorts of a rat soman (GD) model of epilepsy. J Neuroinflammation 2023; 20:163. [PMID: 37438764 PMCID: PMC10337207 DOI: 10.1186/s12974-023-02847-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Accepted: 07/05/2023] [Indexed: 07/14/2023] Open
Abstract
BACKGROUND Acute exposure to seizurogenic organophosphate (OP) nerve agents (OPNA) such as diisopropylfluorophosphate (DFP) or soman (GD), at high concentrations, induce immediate status epilepticus (SE), reactive gliosis, neurodegeneration, and epileptogenesis as a consequence. Medical countermeasures (MCMs-atropine, oximes, benzodiazepines), if administered in < 20 min of OPNA exposure, can control acute symptoms and mortality. However, MCMs alone are inadequate to prevent OPNA-induced brain injury and behavioral dysfunction in survivors. We have previously shown that OPNA exposure-induced SE increases the production of inducible nitric oxide synthase (iNOS) in glial cells in both short- and long- terms. Treating with a water soluble and highly selective iNOS inhibitor, 1400W, for 3 days significantly reduced OPNA-induced brain changes in those animals that had mild-moderate SE in the rat DFP model. However, such mitigating effects and the mechanisms of 1400W are unknown in a highly volatile nerve agent GD exposure. METHODS Mixed-sex cohort of adult Sprague Dawley rats were exposed to GD (132 μg/kg, s.c.) and immediately treated with atropine (2 mg/kg, i.m) and HI-6 (125 mg/kg, i.m.). Severity of seizures were quantified for an hour and treated with midazolam (3 mg/kg, i.m.). An hour post-midazolam, 1400W (20 mg/kg, i.m.) or vehicle was administered daily for 2 weeks. After behavioral testing and EEG acquisition, animals were euthanized at 3.5 months post-GD. Brains were processed for neuroinflammatory and neurodegeneration markers. Serum and CSF were used for nitrooxidative and proinflammatory cytokines assays. RESULTS We demonstrate a significant long-term (3.5 months post-soman) disease-modifying effect of 1400W in animals that had severe SE for > 20 min of continuous convulsive seizures. 1400W significantly reduced GD-induced motor and cognitive dysfunction; nitrooxidative stress (nitrite, ROS; increased GSH: GSSG); proinflammatory cytokines in the serum and some in the cerebrospinal fluid (CSF); epileptiform spikes and spontaneously recurring seizures (SRS) in males; reactive gliosis (GFAP + C3 and IBA1 + CD68-positive glia) as a measure of neuroinflammation, and neurodegeneration (especially parvalbumin-positive neurons) in some brain regions. CONCLUSION These findings demonstrate the long-term disease-modifying effects of a glial-targeted iNOS inhibitor, 1400W, in a rat GD model by modulating reactive gliosis, neurodegeneration (parvalbumin-positive neurons), and neuronal hyperexcitability.
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Affiliation(s)
- Suraj S. Vasanthi
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, 50011 USA
| | - Nikhil S. Rao
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, 50011 USA
| | - Manikandan Samidurai
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, 50011 USA
| | - Nyzil Massey
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, 50011 USA
| | - Christina Meyer
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, 50011 USA
| | - Meghan Gage
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, 50011 USA
| | - Mihir Kharate
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, 50011 USA
| | - Aida Almanza
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, 50011 USA
| | - Logan Wachter
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, 50011 USA
| | - Candide Mafuta
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, 50011 USA
| | - Lily Trevino
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, 50011 USA
| | - Adriana M. Carlo
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, 50011 USA
| | - Elijah Bryant
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, 50011 USA
| | - Brooke E. Corson
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, 50011 USA
| | - Morgan Wohlgemuth
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, 50011 USA
| | - Morgan Ostrander
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, 50011 USA
| | - Lucas Showman
- W.M. Keck Metabolomics Research Laboratory, College of Veterinary Medicine, Iowa State University, Ames, 50011 USA
| | - Chong Wang
- Department of Veterinary Diagnostic and Production Animal Medicine and Statistics, College of Veterinary Medicine, Iowa State University, Ames, 50011 USA
| | - Thimmasettappa Thippeswamy
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, 50011 USA
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11
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Vasanthi SS, Rao NS, Samidurai M, Massey N, Meyer C, Gage M, Kharate M, Almanza A, Wachter L, Mafuta C, Trevino L, Carlo AM, Bryant E, Corson BE, Wohlgemuth M, Ostrander M, Wang C, Thippeswamy T. Disease-Modifying Effects of a Glial-targeted Inducible Nitric Oxide Synthase Inhibitor (1400W) in Mixed-sex Cohorts of a Rat Soman (GD) Model of Epilepsy. RESEARCH SQUARE 2023:rs.3.rs-2883247. [PMID: 37214912 PMCID: PMC10197763 DOI: 10.21203/rs.3.rs-2883247/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Background Acute exposure to seizurogenic organophosphate (OP) nerve agents (OPNA) such as diisopropylfluorophosphate (DFP) or soman (GD), at high concentrations, induce immediate status epilepticus (SE), reactive gliosis, neurodegeneration, and epileptogenesis as a consequence. Medical countermeasures (MCMs- atropine, oximes, benzodiazepines), if administered in < 20 minutes of OPNA exposure, can control acute symptoms and mortality. However, MCMs alone are inadequate to prevent OPNA-induced brain injury and behavioral dysfunction in survivors. We have previously shown that OPNA exposure-induced SE increases the production of inducible nitric oxide synthase (iNOS) in glial cells in both short- and long- terms. Treating with a water soluble and highly selective iNOS inhibitor, 1400W, for three days significantly reduced OPNA-induced brain changes in those animals that had mild-moderate SE in the rat DFP model. However, such mitigating effects and the mechanisms of 1400W are unknown in a highly volatile nerve agent GD exposure. Methods Mixed-sex cohort of adult Sprague Dawley rats were exposed to GD (132µg/kg, s.c.) and immediately treated with atropine (2mg/kg, i.m) and HI-6 (125mg/kg, i.m.). Severity of seizures were quantified for an hour and treated with midazolam (3mg/kg, i.m.). An hour post-midazolam, 1400W (20mg/kg, i.m.) or vehicle was administered daily for two weeks. After behavioral testing and EEG acquisition, animals were euthanized at 3.5 months post-GD. Brains were processed for neuroinflammatory and neurodegeneration markers. Serum and CSF were used for nitrooxidative and proinflammatory cytokines assays. Results We demonstrate a significant long-term (3.5 months post-soman) disease-modifying effect of 1400W in animals that had severe SE for > 20min of continuous convulsive seizures. 1400W significantly reduced GD-induced motor and cognitive dysfunction; nitrooxidative stress (nitrite, ROS; increased GSH: GSSG); proinflammatory cytokines in the serum and some in the cerebrospinal fluid (CSF); epileptiform spikes and spontaneously recurring seizures (SRS) in males; reactive gliosis (GFAP + C3 and IBA1 + CD68 positive glia) as a measure of neuroinflammation, and neurodegeneration (including parvalbumin positive neurons) in some brain regions. Conclusion These findings demonstrate the long-term disease-modifying effects of a glial-targeted iNOS inhibitor, 1400W, in a rat GD model by modulating reactive gliosis, neurodegeneration, and neuronal hyperexcitability.
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12
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Kyle JJ, Sharma S, Tiarks G, Rodriguez S, Bassuk AG. Fast Detection and Quantification of Interictal Spikes and Seizures in a Rodent Model of Epilepsy Using an Automated Algorithm. Bio Protoc 2023; 13:e4632. [PMID: 36968440 PMCID: PMC10031526 DOI: 10.21769/bioprotoc.4632] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Revised: 11/12/2022] [Accepted: 02/13/2023] [Indexed: 03/19/2023] Open
Abstract
The electroencephalogram (EEG) is a powerful tool for analyzing neural activity in various neurological disorders, both in animals and in humans. This technology has enabled researchers to record the brain's abrupt changes in electrical activity with high resolution, thus facilitating efforts to understand the brain's response to internal and external stimuli. The EEG signal acquired from implanted electrodes can be used to precisely study the spiking patterns that occur during abnormal neural discharges. These patterns can be analyzed in conjunction with behavioral observations and serve as an important means for accurate asses sment and quantification of behavioral and electrographic seizures. Numerous algorithms have been developed for the automated quantification of EEG data; however, many of these algorithms were developed with outdated programming languages and require robust computational hardware to run effectively. Additionally, some of these programs require substantial computation time, reducing the relative benefits of automation. Thus, we sought to develop an automated EEG algorithm that was programmed using a familiar programming language (MATLAB), and that could run efficiently without extensive computational demands. This algorithm was developed to quantify interictal spikes and seizures in mice that were subjected to traumatic brain injury. Although the algorithm was designed to be fully automated, it can be operated manually, and all the parameters for EEG activity detection can be easily modified for broad data analysis. Additionally, the algorithm is capable of processing months of lengthy EEG datasets in the order of minutes to hours, reducing both analysis time and errors introduced through manual-based processing.
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Affiliation(s)
- Jackson J. Kyle
- Traumatic Brain Injury and Epilepsy Research Laboratory, Department of Pediatrics, 2040 Medical Laboratories, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242, United States
| | - Shaunik Sharma
- Traumatic Brain Injury and Epilepsy Research Laboratory, Department of Pediatrics, 2040 Medical Laboratories, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242, United States
| | - Grant Tiarks
- Traumatic Brain Injury and Epilepsy Research Laboratory, Department of Pediatrics, 2040 Medical Laboratories, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242, United States
| | - Saul Rodriguez
- Traumatic Brain Injury and Epilepsy Research Laboratory, Department of Pediatrics, 2040 Medical Laboratories, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242, United States
| | - Alexander G. Bassuk
- Traumatic Brain Injury and Epilepsy Research Laboratory, Department of Pediatrics, 2040 Medical Laboratories, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242, United States
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13
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George AG, Farrell JS, Colangeli R, Wall AK, Gom RC, Kesler MT, Rodriguez de la Hoz C, Villa BR, Perera T, Rho JM, Kurrasch D, Teskey GC. Sudden unexpected death in epilepsy is prevented by blocking postictal hypoxia. Neuropharmacology 2023; 231:109513. [PMID: 36948357 DOI: 10.1016/j.neuropharm.2023.109513] [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: 10/19/2022] [Revised: 02/21/2023] [Accepted: 03/18/2023] [Indexed: 03/24/2023]
Abstract
Epilepsy is at times a fatal disease. Sudden unexpected death in epilepsy (SUDEP) is the leading cause of epilepsy-related mortality in people with intractable epilepsy and is defined by exclusion; non-accidental, non-toxicologic, and non-anatomic causes of death. While SUDEP often follows a bilateral tonic-clonic seizure, the mechanisms that ultimately lead to terminal apnea and then asystole remain elusive and there is a lack of preventative treatments. Based on the observation that discrete seizures lead to local and postictal vasoconstriction, resulting in hypoperfusion, hypoxia and behavioural disturbances in the forebrain we reasoned those similar mechanisms may play a role in SUDEP when seizures invade the brainstem. Here we tested this neurovascular-based hypothesis of SUDEP in awake non-anesthetized mice by pharmacologically preventing seizure-induced vasoconstriction, with cyclooxygenase-2 or L-type calcium channel antagonists. In both acute and chronic mouse models of seizure-induced premature mortality, ibuprofen and nicardipine extended life while systemic drug levels remained high enough to be effective. We also examined the potential role of spreading depolarization in the acute model of seizure-induced premature mortality. These data provide a proof-of-principle for the neurovascular hypothesis of SUDEP rather than spreading depolarization and the use of currently available drugs to prevent it.
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Affiliation(s)
- Antis G George
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, T2N 4N1, Canada; Department of Cell Biology and Anatomy, University of Calgary, Calgary, Alberta, Canada
| | - Jordan S Farrell
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, T2N 4N1, Canada; Department of Neurosurgery, Stanford University, Palo Alto, CA, 94305, USA
| | - Roberto Colangeli
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, T2N 4N1, Canada; Department of Cell Biology and Anatomy, University of Calgary, Calgary, Alberta, Canada; Department of Experimental and Clinical Medicine, Section of Neuroscience and Cell Biology, Marche Polytechnic University, Ancona, Italy
| | - Alexandra K Wall
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, T2N 4N1, Canada; Department of Cell Biology and Anatomy, University of Calgary, Calgary, Alberta, Canada
| | - Renaud C Gom
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, T2N 4N1, Canada; Department of Cell Biology and Anatomy, University of Calgary, Calgary, Alberta, Canada
| | - Mitchell T Kesler
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, T2N 4N1, Canada
| | | | - Bianca R Villa
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, T2N 4N1, Canada; Department of Cell Biology and Anatomy, University of Calgary, Calgary, Alberta, Canada
| | - Tefani Perera
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, T2N 4N1, Canada; Department of Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada
| | - Jong M Rho
- Department of Pediatrics, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada; Department of Neurosciences, Pediatrics and Pharmacology, University of California, San Diego and Rady Children's Hospital, San Diego, CA, USA
| | - Deborah Kurrasch
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, T2N 4N1, Canada; Department of Medical Genetics, University of Calgary, Calgary, Alberta, Canada; Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - G Campbell Teskey
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, T2N 4N1, Canada; Department of Cell Biology and Anatomy, University of Calgary, Calgary, Alberta, Canada; Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.
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14
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Wickham J, Ledri M, Andersson M, Kokaia M. Cell-specific switch for epileptiform activity: critical role of interneurons in the mouse subicular network. Cereb Cortex 2023; 33:6171-6183. [PMID: 36611229 PMCID: PMC10183737 DOI: 10.1093/cercor/bhac493] [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: 08/13/2021] [Revised: 11/17/2022] [Accepted: 11/18/2022] [Indexed: 01/09/2023] Open
Abstract
During epileptic seizures, neuronal network activity is hyper synchronized whereby GABAergic parvalbumin-interneurons may have a key role. Previous studies have mostly utilized 4-aminopyridine to induce epileptiform discharges in brain slices from healthy animals. However, it is not clear if the seizure-triggering ability of parvalbumin-interneurons also holds true without the use of external convulsive agents. Here, we investigate whether synchronized activation of parvalbumin-interneurons or principal cells can elicit epileptiform discharges in subiculum slices of epileptic mice. We found that selective synchronized activation of parvalbumin-interneurons or principal cells with optogenetics do not result in light-induced epileptiform discharges (LIEDs) neither in epileptic nor in normal brain slices. Adding 4-aminopyridine to slices, activation of parvalbumin-interneurons still failed to trigger LIEDs. In contrast, such activation of principal neurons readily generated LIEDs with features resembling afterdischarges. When GABAA receptor blocker was added to the perfusion medium, the LIEDs were abolished. These results demonstrate that in subiculum, selective synchronized activation of principal excitatory neurons can trigger epileptiform discharges by recruiting a large pool of downstream interneurons. This study also suggests region-specific role of principal neurons and interneurons in ictogenesis, opening towards differential targeting of specific brain areas for future treatment strategies tailored for individual patients with epilepsy.
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Affiliation(s)
- J Wickham
- Epilepsy Center, Department of Clinical Sciences, Lund University, Sölvegatan 17, 223 62 Lund, Sweden
| | - M Ledri
- Epilepsy Center, Department of Clinical Sciences, Lund University, Sölvegatan 17, 223 62 Lund, Sweden
| | - M Andersson
- Epilepsy Center, Department of Clinical Sciences, Lund University, Sölvegatan 17, 223 62 Lund, Sweden
| | - M Kokaia
- Epilepsy Center, Department of Clinical Sciences, Lund University, Sölvegatan 17, 223 62 Lund, Sweden
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15
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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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16
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Saadi A, Sandouka S, Grad E, Singh PK, Shekh-Ahmad T. Spatial, temporal, and cell-type-specific expression of NADPH Oxidase isoforms following seizure models in rats. Free Radic Biol Med 2022; 190:158-168. [PMID: 35964838 DOI: 10.1016/j.freeradbiomed.2022.08.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 08/02/2022] [Accepted: 08/05/2022] [Indexed: 11/16/2022]
Abstract
The NADPH Oxidase (NOX) enzymes are key producers of reactive oxygen species (ROS) and consist of seven different isoforms, distributed across the tissues and cell types. The increasing level of ROS induces oxidative stress playing a crucial role in neuronal death and the development of epilepsy. Recently, NOX2 was reported as a primary source of ROS production, activated by NMDA receptor, a crucial marker of epilepsy development. Here, we demonstrate spatial, temporal, and cellular expression of NOX2 and NOX4 complexes in in-vitro and in-vivo seizure models. We showed that the expression of NOX2 and NOX4 was increased in the initial 24 h following a brief seizure induced by pentylenetetrazol. Interestingly, while this elevated level returns to baseline 48 h following seizure in the cortex, in the hippocampus these levels remain elevated up to one week following the seizure. Moreover, we showed that 1- and 2- weeks following status epilepticus (SE), expression of NOX2 and NOX4 remains significantly elevated both in the cortex and the hippocampus. Furthermore, in in-vitro seizure model, NOX2 and NOX4 isoforms were overexpressed in neurons and astrocytes following seizures. These results suggest that NOX2 and NOX4 in the brain have a transient response to seizures, and these responses temporally vary depending on, seizure duration, brain region (cortex or hippocampus), and cell types.
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Affiliation(s)
- Aseel Saadi
- The Institute for Drug Research, The School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, 91120, Israel
| | - Sereen Sandouka
- The Institute for Drug Research, The School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, 91120, Israel
| | - Etty Grad
- The Institute for Drug Research, The School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, 91120, Israel
| | - Prince Kumar Singh
- The Institute for Drug Research, The School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, 91120, Israel
| | - Tawfeeq Shekh-Ahmad
- The Institute for Drug Research, The School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, 91120, Israel.
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Liu Y, Tian X, Ke P, Gu J, Ma Y, Guo Y, Xu X, Chen Y, Yang M, Wang X, Xiao F. KIF17 Modulates Epileptic Seizures and Membrane Expression of the NMDA Receptor Subunit NR2B. Neurosci Bull 2022; 38:841-856. [PMID: 35678994 PMCID: PMC9352834 DOI: 10.1007/s12264-022-00888-9] [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: 09/12/2021] [Accepted: 04/01/2022] [Indexed: 10/18/2022] Open
Abstract
Epilepsy is a common and severe brain disease affecting >65 million people worldwide. Recent studies have shown that kinesin superfamily motor protein 17 (KIF17) is expressed in neurons and is involved in regulating the dendrite-targeted transport of N-methyl-D-aspartate receptor subtype 2B (NR2B). However, the effect of KIF17 on epileptic seizures remains to be explored. We found that KIF17 was mainly expressed in neurons and that its expression was increased in epileptic brain tissue. In the kainic acid (KA)-induced epilepsy mouse model, KIF17 overexpression increased the severity of epileptic activity, whereas KIF17 knockdown had the opposite effect. In electrophysiological tests, KIF17 regulated excitatory synaptic transmission, potentially due to KIF17-mediated NR2B membrane expression. In addition, this report provides the first demonstration that KIF17 is modified by SUMOylation (SUMO, small ubiquitin-like modifier), which plays a vital role in the stabilization and maintenance of KIF17 in epilepsy.
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Affiliation(s)
- Yan Liu
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing, 400016, China
| | - Xin Tian
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing, 400016, China
| | - Pingyang Ke
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing, 400016, China
| | - Juan Gu
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing, 400016, China
| | - Yuanlin Ma
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing, 400016, China
| | - Yi Guo
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing, 400016, China
| | - Xin Xu
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing, 400016, China
| | - Yuanyuan Chen
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing, 400016, China
| | - Min Yang
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing, 400016, China
| | - Xuefeng Wang
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing, 400016, China.
| | - Fei Xiao
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing, 400016, China.
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18
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Rao NS, Meyer C, Vasanthi SS, Massey N, Samidurai M, Gage M, Putra M, Almanza AN, Wachter L, Thippeswamy T. DFP-Induced Status Epilepticus Severity in Mixed-Sex Cohorts of Adult Rats Housed in the Same Room: Behavioral and EEG Comparisons. Front Cell Dev Biol 2022; 10:895092. [PMID: 35620057 PMCID: PMC9127803 DOI: 10.3389/fcell.2022.895092] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Accepted: 04/19/2022] [Indexed: 11/26/2022] Open
Abstract
Sex is a biological variable in experimental models. In our previous diisopropylfluorophosphate (DFP) studies, female rats required a higher dose of DFP to achieve a somewhat similar severity of status epilepticus (SE) as males. In those studies, male and female rats were bought separately from the same vendor, housed in different rooms, and the DFP used was from different batches. We had also shown that surgery for epidural electrodes implantation reduces the threshold for SE. Our recent study in the soman (GD) model using a mixed-sex cohort of rats housed individually but in the same room showed that females achieved significantly higher SE severity than males for the same dose of GD. In this study, we demonstrate that housing the mixed-sex cohorts in the same room and treating them with DFP (4 mg/kg, s.c.) from the same pool, though from different batches, yielded reproducible SE severity in both sexes and both telemetry (surgery) and non-telemetry (non-surgery) groups. We conducted experiments in four mixed-sex cohorts of adult Sprague-Dawley rats. In females, the surgery for implanting the telemetry devices reduced the latency to convulsive seizure (CS) and increased SE severity compared to non-telemetry females. However, there were no sex differences in latency or SE severity within telemetry or non-telemetry groups. Once animals reached CS stage ≥3, they remained in CS stage in both sexes until midazolam was administered. Midazolam (3 mg/kg, i.m.) treatment 1-one-hour post-DFP significantly reduced epileptiform spikes in both sexes. The mortality was only 2% in 24 h. Irrespective of sex or stage of estrous cycle or surgery, the animals had continuous convulsive SE for ∼40 min. In telemetry rats, electrographic changes correlated with behavioral seizures. However, there was a significant difference in SE severity and the latency between directly-observed behavioral CS and EEG-based CS quantification in both sexes. Overall, these results suggest that housing both sexes in the same room and treating with DFP in a mixed-sex cohort from the same pool of reagents will minimize variability in SE severity. Such rigorous experiments will yield better outcomes while testing disease-modifying agents in epilepsy models.
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Affiliation(s)
- Nikhil S Rao
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, United States
| | - Christina Meyer
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, United States
| | - Suraj S Vasanthi
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, United States
| | - Nyzil Massey
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, United States
| | - Manikandan Samidurai
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, United States
| | - Meghan Gage
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, United States
| | - Marson Putra
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, United States
| | - Aida N Almanza
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, United States
| | - Logan Wachter
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, United States
| | - Thimmasettappa Thippeswamy
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, United States
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19
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GABA A Receptor Autoantibodies Decrease GABAergic Synaptic Transmission in the Hippocampal CA3 Network. Int J Mol Sci 2022; 23:ijms23073707. [PMID: 35409067 PMCID: PMC8998798 DOI: 10.3390/ijms23073707] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2022] [Revised: 03/19/2022] [Accepted: 03/23/2022] [Indexed: 12/04/2022] Open
Abstract
Autoimmune encephalitis associated with antibodies (Abs) against α1, β3, and γ2 subunits of γ-aminobutyric acid receptor A (GABAAR) represents a severe form of encephalitis with refractory seizures and status epilepticus. Reduction in inhibitory GABAergic synaptic activity is linked to dysfunction of neuronal networks, hyperexcitability, and seizures. The aim in this study was to investigate the direct pathogenic effect of a recombinant GABAAR autoantibody (rAb-IP2), derived from the cerebrospinal fluid (CSF) of a patient with autoimmune GABAAR encephalitis, on hippocampal CA1 and CA3 networks. Acute brain slices from C57BL/6 mice were incubated with rAb-IP2. The spontaneous synaptic GABAergic transmission was measured using electrophysiological recordings in voltage-clamp mode. The GABAAR autoantibody rAb-IP2 reduced inhibitory postsynaptic signaling in the hippocampal CA1 pyramidal neurons with regard to the number of spontaneous inhibitory postsynaptic currents (sIPSCs) but did not affect their amplitude. In the hippocampal CA3 network, decreased number and amplitude of sIPSCs were detected, leading to decreased GABAergic synaptic transmission. Immunohistochemical staining confirmed the rAb-IP2 bound to hippocampal tissue. These findings suggest that GABAAR autoantibodies exert direct functional effects on both hippocampal CA1 and CA3 pyramidal neurons and play a crucial role in seizure generation in GABAAR autoimmune encephalitis.
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20
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Yin L, Gao DS, Hu JM, Zhong C, Xi W. Long-term development of dynamic changes in neurovascular coupling after acute temporal lobe epilepsy. Brain Res 2022; 1784:147858. [PMID: 35245486 DOI: 10.1016/j.brainres.2022.147858] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 02/23/2022] [Accepted: 02/27/2022] [Indexed: 12/25/2022]
Abstract
Epilepsy is an abnormal brain state that may be induced by synchronous neuronal activation and also abnormalities in energy metabolism or the oxygen supply vascular system. Neurovascular coupling (NVC), the relationship between neuron, capillary, and penetrating artery, remains unexplored on a fine-scale with respect to the pathology process after acute temporal lobe epilepsy (TLE). Here we use two-photon microscopy (TPM) to provide high temporal-spatial resolution imaging to identify changes in NVC during spontaneous and electro-stimulated (ES) states in awake mice. Implantation of a long-term craniotomy window allowed TPM recording of the pathological development after the acute Kainic Acid temporal lobe epilepsy model. Our results provide direct evidence that the capillary and penetrating artery are not correlated to rhythmic neuronal activity during acute epilepsy. During the CSD period, NVC shows a strong correlation. We demonstrate that NVC exhibits nonlinear dynamics after status epilepticus. Furthermore, the vascular correlation to neuronal signals in spontaneous and ES states shows dynamic changes which correlate to the evolution after acute TLE. Understanding NVC in all TLE stages, from the acute through the TLE pathological development, may provide new therapeutic pathways.
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Affiliation(s)
- Liu Yin
- Interdisciplinary Institute of Neuroscience and Technology, Department of Anesthesiology, the Second Affiliated Hospital, School of Medicine, Zhejiang University, Kaixuan Road 258th, Hangzhou, 310020, PR China
| | - Dave Schwinn Gao
- Department of Anesthesiology, the Second Affiliated Hospital, School of Medicine, Zhejiang University, Jiefang Road 88th, Hangzhou, 310016, PR China
| | - Jia Ming Hu
- Interdisciplinary Institute of Neuroscience and Technology, Department of Anesthesiology, the Second Affiliated Hospital, School of Medicine, Zhejiang University, Kaixuan Road 258th, Hangzhou, 310020, PR China
| | - Chen Zhong
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, College of Pharmaceutical Science, Zhejiang Chinese Medical University, Hangzhou, China. Institute of Pharmacology and Toxicology, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China. Epilepsy Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China.
| | - Wang Xi
- Interdisciplinary Institute of Neuroscience and Technology, Department of Anesthesiology, the Second Affiliated Hospital, School of Medicine, Zhejiang University, Kaixuan Road 258th, Hangzhou, 310020, PR China; Key Laboratory of Biomedical Engineering of Ministry of Education, College of Biomedical Engineering and instrument Science, Zhejiang University, Hangzhou 310027, PR China.
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21
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Gage M, Rao NS, Samidurai M, Putra M, Vasanthi SS, Meyer C, Wang C, Thippeswamy T. Soman (GD) Rat Model to Mimic Civilian Exposure to Nerve Agent: Mortality, Video-EEG Based Status Epilepticus Severity, Sex Differences, Spontaneously Recurring Seizures, and Brain Pathology. Front Cell Neurosci 2022; 15:798247. [PMID: 35197823 PMCID: PMC8859837 DOI: 10.3389/fncel.2021.798247] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 12/27/2021] [Indexed: 12/14/2022] Open
Abstract
Modeling a real-world scenario of organophosphate nerve agent (OPNA) exposure is challenging. Military personnel are premedicated with pyridostigmine, which led to the development of OPNA models with pyridostigmine/oxime pretreatment to investigate novel therapeutics for acute and chronic effects. However, civilians are not premedicated with pyridostigmine/oxime. Therefore, experimental models without pyridostigmine were developed by other laboratories though often only in males. Following OPNA exposure, prolonged convulsive seizures (CS) or status epilepticus (SE) are concerning. The duration and severity of CS/SE determine the extent of brain injury in survivors even after treating with medical countermeasures (MCM)/antidotes such as atropine, an oxime, and an anticonvulsant such as diazepam/midazolam. In this study, using a large mixed sex cohort of adult male and female rats, without pretreatment, we demonstrate severe SE lasting for >20 min in 82% of the animals in response to soman (GD,132 μg/kg, s.c.). Atropine sulfate (2 mg/kg, i.m.) and HI-6 (125 mg/kg, i.m.) were administered immediately following soman, and midazolam (3 mg/kg, i.m.) 1 h post-exposure. Immediate MCM treatment is impractical in civilian exposure to civilians, but this approach reduces mortality in experimental models. Interestingly, female rats, irrespective of estrous stages, had an average of 44 min CS (stage ≥ 3), while males had an average of 32 min CS during SE, starting from soman exposure to midazolam treatment. However, in telemetry device implanted groups, there were no significant sex differences in SE severity; males had 40 min and females 43 min of continuous CS until midazolam was administered. No animals died prior to midazolam administration and less than 5% died in the first week after soman intoxication. In telemetered animals, there was a direct correlation between EEG changes and behavioral seizures in real-time. In the long-term, convulsive spontaneously recurring seizures (SRS) were observed in 85% of randomly chosen animals. At 4-months post-soman, the brain histology confirmed reactive gliosis and neurodegeneration. The novel findings of this study are that, in non-telemetered animals, the SE severity following soman intoxication was significantly greater in females compared to males and that the estrous cycle did not influence the response.
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Affiliation(s)
- Meghan Gage
- Neuroscience Interdepartmental Program, Iowa State University, Ames, IA, United States.,Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, United States
| | - Nikhil S Rao
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, United States
| | - Manikandan Samidurai
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, United States
| | - Marson Putra
- Neuroscience Interdepartmental Program, Iowa State University, Ames, IA, United States.,Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, United States
| | - Suraj S Vasanthi
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, United States
| | - Christina Meyer
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, United States
| | - Chong Wang
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, United States
| | - Thimmasettappa Thippeswamy
- Neuroscience Interdepartmental Program, Iowa State University, Ames, IA, United States.,Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, United States
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22
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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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23
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Gage M, Putra M, Gomez-Estrada C, Golden M, Wachter L, Gard M, Thippeswamy T. Differential Impact of Severity and Duration of Status Epilepticus, Medical Countermeasures, and a Disease-Modifier, Saracatinib, on Brain Regions in the Rat Diisopropylfluorophosphate Model. Front Cell Neurosci 2021; 15:772868. [PMID: 34720886 PMCID: PMC8555467 DOI: 10.3389/fncel.2021.772868] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Accepted: 09/28/2021] [Indexed: 11/29/2022] Open
Abstract
Acute organophosphate (OP) toxicity poses a significant threat to both military and civilian personnel as it can lead to a variety of cholinergic symptoms including the development of status epilepticus (SE). Depending on its severity, SE can lead to a spectrum of neurological changes including neuroinflammation and neurodegeneration. In this study, we determined the impact of SE severity and duration on disease promoting parameters such as gliosis and neurodegeneration and the efficacy of a disease modifier, saracatinib (AZD0530), a Src/Fyn tyrosine kinase inhibitor. Animals were exposed to 4 mg/kg diisopropylfluorophosphate (DFP, s.c.) followed by medical countermeasures. We had five experimental groups: controls (no DFP), animals with no continuous convulsive seizures (CS), animals with ∼20-min continuous CS, 31-60-min continuous CS, and > 60-min continuous CS. These groups were then assessed for astrogliosis, microgliosis, and neurodegeneration 8 days after DFP exposure. The 31-60-min and > 60-min groups, but not ∼20-min group, had significantly upregulated gliosis and neurodegeneration in the hippocampus compared to controls. In the piriform cortex and amygdala, however, all three continuous CS groups had significant upregulation in both gliosis and neurodegeneration. In a separate cohort of animals that had ∼20 and > 60-min of continuous CS, we administered saracatinib for 7 days beginning three hours after DFP. There was bodyweight loss and mortality irrespective of the initial SE severity and duration. However, in survived animals, saracatinib prevented spontaneous recurrent seizures (SRS) during the first week in both severity groups. In the ∼20-min CS group, compared to the vehicle, saracatinib significantly reduced neurodegeneration in the piriform cortex and amygdala. There were no significant differences in the measured parameters between the naïve control and saracatinib on its own (without DFP) groups. Overall, this study demonstrates the differential effects of the initial SE severity and duration on the localization of gliosis and neurodegeneration. We have also demonstrated the disease-modifying potential of saracatinib. However, its’ dosing regimen should be optimized based on initial severity and duration of CS during SE to maximize therapeutic effects and minimize toxicity in the DFP model as well as in other OP models such as soman.
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Affiliation(s)
- Meghan Gage
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, United States.,Neuroscience Interdepartmental Program, Iowa State University, Ames, IA, United States
| | - Marson Putra
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, United States.,Neuroscience Interdepartmental Program, Iowa State University, Ames, IA, United States
| | - Crystal Gomez-Estrada
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, United States
| | - Madison Golden
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, United States
| | - Logan Wachter
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, United States
| | - Megan Gard
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, United States
| | - Thimmasettappa Thippeswamy
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, United States.,Neuroscience Interdepartmental Program, Iowa State University, Ames, IA, United States
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24
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Kreye J, Wright SK, van Casteren A, Stöffler L, Machule ML, Reincke SM, Nikolaus M, van Hoof S, Sanchez-Sendin E, Homeyer MA, Cordero Gómez C, Kornau HC, Schmitz D, Kaindl AM, Boehm-Sturm P, Mueller S, Wilson MA, Upadhya MA, Dhangar DR, Greenhill S, Woodhall G, Turko P, Vida I, Garner CC, Wickel J, Geis C, Fukata Y, Fukata M, Prüss H. Encephalitis patient-derived monoclonal GABAA receptor antibodies cause epileptic seizures. THE JOURNAL OF EXPERIMENTAL MEDICINE 2021; 218:212650. [PMID: 34546336 PMCID: PMC8480667 DOI: 10.1084/jem.20210012] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 06/30/2021] [Accepted: 08/17/2021] [Indexed: 11/04/2022]
Abstract
Autoantibodies targeting the GABAA receptor (GABAAR) hallmark an autoimmune encephalitis presenting with frequent seizures and psychomotor abnormalities. Their pathogenic role is still not well-defined, given the common overlap with further autoantibodies and the lack of patient-derived mAbs. Five GABAAR mAbs from cerebrospinal fluid cells bound to various epitopes involving the α1 and γ2 receptor subunits, with variable binding strength and partial competition. mAbs selectively reduced GABAergic currents in neuronal cultures without causing receptor internalization. Cerebroventricular infusion of GABAAR mAbs and Fab fragments into rodents induced a severe phenotype with seizures and increased mortality, reminiscent of encephalitis patients' symptoms. Our results demonstrate direct pathogenicity of autoantibodies on GABAARs independent of Fc-mediated effector functions and provide an animal model for GABAAR encephalitis. They further provide the scientific rationale for clinical treatments using antibody depletion and can serve as tools for the development of antibody-selective immunotherapies.
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Affiliation(s)
- Jakob Kreye
- German Center for Neurodegenerative Diseases (DZNE) Berlin, Berlin, Germany.,Helmholtz Innovation Lab BaoBab (Brain antibody-omics and B-cell Lab), Berlin, Germany.,Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Neurology and Experimental Neurology, Berlin, Germany.,Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Pediatric Neurology, Berlin, Germany.,Berlin Institute of Health, Berlin, Germany
| | - Sukhvir K Wright
- Institute of Health and Neurodevelopment, College of Health and Life Sciences, Aston University, Birmingham, UK.,Department of Paediatric Neurology, The Birmingham Women's and Children's Hospital National Health Service Foundation Trust, Birmingham, UK
| | | | - Laura Stöffler
- German Center for Neurodegenerative Diseases (DZNE) Berlin, Berlin, Germany.,Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Neurology and Experimental Neurology, Berlin, Germany
| | - Marie-Luise Machule
- German Center for Neurodegenerative Diseases (DZNE) Berlin, Berlin, Germany.,Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Neurology and Experimental Neurology, Berlin, Germany
| | - S Momsen Reincke
- German Center for Neurodegenerative Diseases (DZNE) Berlin, Berlin, Germany.,Helmholtz Innovation Lab BaoBab (Brain antibody-omics and B-cell Lab), Berlin, Germany.,Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Neurology and Experimental Neurology, Berlin, Germany.,Berlin Institute of Health, Berlin, Germany
| | - Marc Nikolaus
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Pediatric Neurology, Berlin, Germany.,Department of Paediatric Neurology, The Birmingham Women's and Children's Hospital National Health Service Foundation Trust, Birmingham, UK.,Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Center for Chronically Sick Children, Berlin, Germany
| | - Scott van Hoof
- German Center for Neurodegenerative Diseases (DZNE) Berlin, Berlin, Germany.,Helmholtz Innovation Lab BaoBab (Brain antibody-omics and B-cell Lab), Berlin, Germany.,Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Neurology and Experimental Neurology, Berlin, Germany
| | - Elisa Sanchez-Sendin
- German Center for Neurodegenerative Diseases (DZNE) Berlin, Berlin, Germany.,Helmholtz Innovation Lab BaoBab (Brain antibody-omics and B-cell Lab), Berlin, Germany.,Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Neurology and Experimental Neurology, Berlin, Germany
| | - Marie A Homeyer
- German Center for Neurodegenerative Diseases (DZNE) Berlin, Berlin, Germany.,Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Neurology and Experimental Neurology, Berlin, Germany
| | - César Cordero Gómez
- German Center for Neurodegenerative Diseases (DZNE) Berlin, Berlin, Germany.,Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Neurology and Experimental Neurology, Berlin, Germany
| | - Hans-Christian Kornau
- German Center for Neurodegenerative Diseases (DZNE) Berlin, Berlin, Germany.,Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Neuroscience Research Center, Cluster NeuroCure, Berlin, Germany
| | - Dietmar Schmitz
- German Center for Neurodegenerative Diseases (DZNE) Berlin, Berlin, Germany.,Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Neuroscience Research Center, Cluster NeuroCure, Berlin, Germany
| | - Angela M Kaindl
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Pediatric Neurology, Berlin, Germany.,Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Center for Chronically Sick Children, Berlin, Germany.,Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Cell Biology and Neurobiology, Berlin, Germany
| | - Philipp Boehm-Sturm
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Neurology and Experimental Neurology, Berlin, Germany.,Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Neuroscience Research Center, Cluster NeuroCure, Berlin, Germany
| | - Susanne Mueller
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Neurology and Experimental Neurology, Berlin, Germany.,Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Neuroscience Research Center, Cluster NeuroCure, Berlin, Germany
| | - Max A Wilson
- Institute of Health and Neurodevelopment, College of Health and Life Sciences, Aston University, Birmingham, UK
| | - Manoj A Upadhya
- Institute of Health and Neurodevelopment, College of Health and Life Sciences, Aston University, Birmingham, UK
| | - Divya R Dhangar
- Institute of Health and Neurodevelopment, College of Health and Life Sciences, Aston University, Birmingham, UK
| | - Stuart Greenhill
- Institute of Health and Neurodevelopment, College of Health and Life Sciences, Aston University, Birmingham, UK
| | - Gavin Woodhall
- Institute of Health and Neurodevelopment, College of Health and Life Sciences, Aston University, Birmingham, UK
| | - Paul Turko
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität Berlin, Department of Integrative Neuroanatomy, Berlin, Germany
| | - Imre Vida
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität Berlin, Department of Integrative Neuroanatomy, Berlin, Germany
| | - Craig C Garner
- German Center for Neurodegenerative Diseases (DZNE) Berlin, Berlin, Germany
| | - Jonathan Wickel
- Section of Translational Neuroimmunology, Department of Neurology, Jena University Hospital, Jena, Germany
| | - Christian Geis
- Section of Translational Neuroimmunology, Department of Neurology, Jena University Hospital, Jena, Germany
| | - Yuko Fukata
- Division of Membrane Physiology, Department of Molecular and Cellular Physiology, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki, Japan.,Department of Physiological Sciences, School of Life Science, SOKENDAI, The Graduate University for Advanced Studies, Okazaki, Japan
| | - Masaki Fukata
- Division of Membrane Physiology, Department of Molecular and Cellular Physiology, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki, Japan.,Department of Physiological Sciences, School of Life Science, SOKENDAI, The Graduate University for Advanced Studies, Okazaki, Japan
| | - Harald Prüss
- German Center for Neurodegenerative Diseases (DZNE) Berlin, Berlin, Germany.,Helmholtz Innovation Lab BaoBab (Brain antibody-omics and B-cell Lab), Berlin, Germany.,Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Neurology and Experimental Neurology, Berlin, Germany
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25
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Broekaart DW, Bertran A, Jia S, Korotkov A, Senkov O, Bongaarts A, Mills JD, Anink JJ, Seco J, Baayen JC, Idema S, Chabrol E, Becker AJ, Wadman WJ, Tarragó T, Gorter JA, Aronica E, Prades R, Dityatev A, van Vliet EA. The matrix metalloproteinase inhibitor IPR-179 has antiseizure and antiepileptogenic effects. J Clin Invest 2021; 131:138332. [PMID: 33141761 DOI: 10.1172/jci138332] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 10/29/2020] [Indexed: 12/17/2022] Open
Abstract
Matrix metalloproteinases (MMPs) are synthesized by neurons and glia and released into the extracellular space, where they act as modulators of neuroplasticity and neuroinflammatory agents. Development of epilepsy (epileptogenesis) is associated with increased expression of MMPs, and therefore, they may represent potential therapeutic drug targets. Using quantitative PCR (qPCR) and immunohistochemistry, we studied the expression of MMPs and their endogenous inhibitors tissue inhibitors of metalloproteinases (TIMPs) in patients with status epilepticus (SE) or temporal lobe epilepsy (TLE) and in a rat TLE model. Furthermore, we tested the MMP2/9 inhibitor IPR-179 in the rapid-kindling rat model and in the intrahippocampal kainic acid mouse model. In both human and experimental epilepsy, MMP and TIMP expression were persistently dysregulated in the hippocampus compared with in controls. IPR-179 treatment reduced seizure severity in the rapid-kindling model and reduced the number of spontaneous seizures in the kainic acid model (during and up to 7 weeks after delivery) without side effects while improving cognitive behavior. Moreover, our data suggest that IPR-179 prevented an MMP2/9-dependent switch-off normally restraining network excitability during the activity period. Since increased MMP expression is a prominent hallmark of the human epileptogenic brain and the MMP inhibitor IPR-179 exhibits antiseizure and antiepileptogenic effects in rodent epilepsy models and attenuates seizure-induced cognitive decline, it deserves further investigation in clinical trials.
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Affiliation(s)
- Diede Wm Broekaart
- Amsterdam UMC, University of Amsterdam, Department of (Neuro)Pathology, Amsterdam Neuroscience, Amsterdam, Netherlands
| | | | - Shaobo Jia
- Molecular Neuroplasticity Group, German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Germany
| | - Anatoly Korotkov
- Amsterdam UMC, University of Amsterdam, Department of (Neuro)Pathology, Amsterdam Neuroscience, Amsterdam, Netherlands
| | - Oleg Senkov
- Molecular Neuroplasticity Group, German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Germany
| | - Anika Bongaarts
- Amsterdam UMC, University of Amsterdam, Department of (Neuro)Pathology, Amsterdam Neuroscience, Amsterdam, Netherlands
| | - James D Mills
- Amsterdam UMC, University of Amsterdam, Department of (Neuro)Pathology, Amsterdam Neuroscience, Amsterdam, Netherlands
| | - Jasper J Anink
- Amsterdam UMC, University of Amsterdam, Department of (Neuro)Pathology, Amsterdam Neuroscience, Amsterdam, Netherlands
| | - Jesús Seco
- Accure Therapeutics S.L., Barcelona, Spain
| | - Johannes C Baayen
- Amsterdam UMC, Vrije Universiteit Amsterdam, Department of Neurosurgery, Amsterdam Neuroscience, Amsterdam, Netherlands
| | - Sander Idema
- Amsterdam UMC, Vrije Universiteit Amsterdam, Department of Neurosurgery, Amsterdam Neuroscience, Amsterdam, Netherlands
| | - Elodie Chabrol
- UCL Institute of Neurology, University College London, London, United Kingdom
| | - Albert J Becker
- Section for Translational Epilepsy Research, Department of Neuropathology, University of Bonn Medical Center, Bonn, Germany
| | - Wytse J Wadman
- Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, Amsterdam, Netherlands
| | | | - Jan A Gorter
- Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, Amsterdam, Netherlands
| | - Eleonora Aronica
- Amsterdam UMC, University of Amsterdam, Department of (Neuro)Pathology, Amsterdam Neuroscience, Amsterdam, Netherlands.,Stichting Epilepsie Instellingen Nederland (SEIN), Heemstede, Netherlands
| | | | - Alexander Dityatev
- Molecular Neuroplasticity Group, German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Germany.,Medical Faculty, Otto von Guericke University Magdeburg, Magdeburg, Germany.,Center for Behavioral Brain Sciences (CBBS) Magdeburg, Magdeburg, Germany
| | - Erwin A van Vliet
- Amsterdam UMC, University of Amsterdam, Department of (Neuro)Pathology, Amsterdam Neuroscience, Amsterdam, Netherlands.,Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, Amsterdam, Netherlands
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Sturgeon ML, Langton R, Sharma S, Cornell RA, Glykys J, Bassuk AG. The opioid antagonist naltrexone decreases seizure-like activity in genetic and chemically induced epilepsy models. Epilepsia Open 2021; 6:528-538. [PMID: 34664432 PMCID: PMC8408599 DOI: 10.1002/epi4.12512] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 04/23/2021] [Accepted: 05/18/2021] [Indexed: 12/23/2022] Open
Abstract
OBJECTIVE A significant number of epileptic patients fail to respond to available anticonvulsive medications. To find new anticonvulsive medications, we evaluated FDA-approved drugs not known to be anticonvulsants. Using zebrafish larvae as an initial model system, we found that the opioid antagonist naltrexone exhibited an anticonvulsant effect. We validated this effect in three other epilepsy models and present naltrexone as a promising anticonvulsive candidate. METHODS Candidate anticonvulsant drugs, determined by our prior transcriptomics analysis of hippocampal tissue, were evaluated in a larval zebrafish model of human Dravet syndrome (scn1Lab mutants), in wild-type zebrafish larvae treated with the pro-convulsant drug pentylenetetrazole (PTZ), in wild-type C57bl/6J acute brain slices exposed to PTZ, and in wild-type mice treated with PTZ in vivo. Abnormal locomotion was determined behaviorally in zebrafish and mice and by field potential in neocortex layer IV/V and CA1 stratum pyramidale in the hippocampus. RESULTS The opioid antagonist naltrexone decreased abnormal locomotion in the larval zebrafish model of human Dravet syndrome (scn1Lab mutants) and wild-type larvae treated with the pro-convulsant drug PTZ. Naltrexone also decreased seizure-like events in acute brain slices of wild-type mice, and the duration and number of seizures in adult mice injected with PTZ. SIGNIFICANCE Our data reveal that naltrexone has anticonvulsive properties and is a candidate drug for seizure treatment.
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Affiliation(s)
| | - Rachel Langton
- Department of PediatricsDivision of Child NeurologyUniversity of IowaIowa CityIAUSA
- Iowa Neuroscience InstituteUniversity of IowaIowa CityIAUSA
| | | | - Robert A. Cornell
- Department of Anatomy and Cell BiologyUniversity of IowaIowa CityIAUSA
| | - Joseph Glykys
- Department of PediatricsDivision of Child NeurologyUniversity of IowaIowa CityIAUSA
- Iowa Neuroscience InstituteUniversity of IowaIowa CityIAUSA
- Department of NeurologyUniversity of IowaIowa CityIAUSA
| | - Alexander G. Bassuk
- Department of PediatricsDivision of Child NeurologyUniversity of IowaIowa CityIAUSA
- Iowa Neuroscience InstituteUniversity of IowaIowa CityIAUSA
- Department of NeurologyUniversity of IowaIowa CityIAUSA
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Sharma S, Carlson S, Gregory-Flores A, Hinojo-Perez A, Olson A, Thippeswamy T. Mechanisms of disease-modifying effect of saracatinib (AZD0530), a Src/Fyn tyrosine kinase inhibitor, in the rat kainate model of temporal lobe epilepsy. Neurobiol Dis 2021; 156:105410. [PMID: 34087381 PMCID: PMC8325782 DOI: 10.1016/j.nbd.2021.105410] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 05/16/2021] [Accepted: 05/30/2021] [Indexed: 02/07/2023] Open
Abstract
We have recently demonstrated the role of the Fyn-PKCδ signaling pathway in status epilepticus (SE)-induced neuroinflammation and epileptogenesis in experimental models of temporal lobe epilepsy (TLE). In this study, we show a significant disease-modifying effect and the mechanisms of a Fyn/Src tyrosine kinase inhibitor, saracatinib (SAR, also known as AZD0530), in the rat kainate (KA) model of TLE. SAR treatment for a week, starting the first dose (25 mg/kg, oral) 4 h after the onset of SE, significantly reduced spontaneously recurring seizures and epileptiform spikes during the four months of continuous video-EEG monitoring. Immunohistochemistry of brain sections and Western blot analyses of hippocampal lysates at 8-day (8d) and 4-month post-SE revealed a significant reduction of SE-induced astrogliosis, microgliosis, neurodegeneration, phosphorylated Fyn/Src-419 and PKCδ-tyr311, in SAR-treated group when compared with the vehicle control. We also found the suppression of nitroxidative stress markers such as iNOS, 3-NT, 4-HNE, and gp91phox in the hippocampus, and nitrite and ROS levels in the serum of the SAR-treated group at 8d post-SE. The qRT-PCR (hippocampus) and ELISA (serum) revealed a significant reduction of key proinflammatory cytokines TNFα and IL-1β mRNA in the hippocampus and their protein levels in serum, in addition to IL-6 and IL-12, in the SAR-treated group at 8d in contrast to the vehicle-treated group. These findings suggest that SAR targets some of the key biomarkers of epileptogenesis and modulates neuroinflammatory and nitroxidative pathways that mediate the development of epilepsy. Therefore, SAR can be developed as a potential disease-modifying agent to prevent the development and progression of TLE.
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Affiliation(s)
- Shaunik Sharma
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames 50011, USA
| | - Steven Carlson
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames 50011, USA
| | - Adriana Gregory-Flores
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames 50011, USA
| | - Andy Hinojo-Perez
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames 50011, USA
| | - Ashley Olson
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames 50011, USA
| | - Thimmasettappa Thippeswamy
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames 50011, USA.
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28
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Tse K, Beamer E, Simpson D, Beynon RJ, Sills GJ, Thippeswamy T. The Impacts of Surgery and Intracerebral Electrodes in C57BL/6J Mouse Kainate Model of Epileptogenesis: Seizure Threshold, Proteomics, and Cytokine Profiles. Front Neurol 2021; 12:625017. [PMID: 34322075 PMCID: PMC8312573 DOI: 10.3389/fneur.2021.625017] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 06/07/2021] [Indexed: 01/01/2023] Open
Abstract
Intracranial electroencephalography (EEG) is commonly used to study epileptogenesis and epilepsy in experimental models. Chronic gliosis and neurodegeneration at the injury site are known to be associated with surgically implanted electrodes in both humans and experimental models. Currently, however, there are no reports on the impact of intracerebral electrodes on proteins in the hippocampus and proinflammatory cytokines in the cerebral cortex and plasma in experimental models. We used an unbiased, label-free proteomics approach to identify the altered proteins in the hippocampus, and multiplex assay for cytokines in the cerebral cortex and plasma of C57BL/6J mice following bilateral surgical implantation of electrodes into the cerebral hemispheres. Seven days following surgery, a repeated low dose kainate (KA) regimen was followed to induce status epilepticus (SE). Surgical implantation of electrodes reduced the amount of KA necessary to induce SE by 50%, compared with mice without surgery. Tissues were harvested 7 days post-SE (i.e., 14 days post-surgery) and compared with vehicle-treated mice. Proteomic profiling showed more proteins (103, 6.8% of all proteins identified) with significantly changed expression (p < 0.01) driven by surgery than by KA treatment itself without surgery (27, 1.8% of all proteins identified). Further, electrode implantation approximately doubled the number of KA-induced changes in protein expression (55, 3.6% of all identified proteins). Further analysis revealed that intracerebral electrodes and KA altered the expression of proteins associated with epileptogenesis such as inflammation (C1q system), neurodegeneration (cystatin-C, galectin-1, cathepsin B, heat-shock protein 25), blood–brain barrier dysfunction (fibrinogen-α, serum albumin, α2 macroglobulin), and gliosis (vimentin, GFAP, filamin-A). The multiplex assay revealed a significant increase in key cytokines such as TNFα, IL-1β, IL-4, IL-5, IL-6, IL-10, IL12p70, IFN-γ, and KC/GRO in the cerebral cortex and some in the plasma in the surgery group. Overall, these findings demonstrate that surgical implantation of depth electrodes alters some of the molecules that may have a role in epileptogenesis in experimental models.
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Affiliation(s)
- Karen Tse
- Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, United Kingdom.,Department of Molecular and Clinical Pharmacology, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Edward Beamer
- Department of Molecular and Clinical Pharmacology, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Deborah Simpson
- Centre for Proteome Research, Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Robert J Beynon
- Centre for Proteome Research, Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Graeme J Sills
- Department of Molecular and Clinical Pharmacology, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Thimmasettappa Thippeswamy
- Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, United Kingdom
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29
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The Kainic Acid Models of Temporal Lobe Epilepsy. eNeuro 2021; 8:ENEURO.0337-20.2021. [PMID: 33658312 PMCID: PMC8174050 DOI: 10.1523/eneuro.0337-20.2021] [Citation(s) in RCA: 74] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 01/14/2021] [Accepted: 01/24/2021] [Indexed: 12/14/2022] Open
Abstract
Experimental models of epilepsy are useful to identify potential mechanisms of epileptogenesis, seizure genesis, comorbidities, and treatment efficacy. The kainic acid (KA) model is one of the most commonly used. Several modes of administration of KA exist, each producing different effects in a strain-, species-, gender-, and age-dependent manner. In this review, we discuss the advantages and limitations of the various forms of KA administration (systemic, intrahippocampal, and intranasal), as well as the histologic, electrophysiological, and behavioral outcomes in different strains and species. We attempt a personal perspective and discuss areas where work is needed. The diversity of KA models and their outcomes offers researchers a rich palette of phenotypes, which may be relevant to specific traits found in patients with temporal lobe epilepsy.
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30
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Chen KD, Hall AM, Garcia-Curran MM, Sanchez GA, Daglian J, Luo R, Baram TZ. Augmented seizure susceptibility and hippocampal epileptogenesis in a translational mouse model of febrile status epilepticus. Epilepsia 2021; 62:647-658. [PMID: 33475157 DOI: 10.1111/epi.16814] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Revised: 12/22/2020] [Accepted: 12/23/2020] [Indexed: 12/31/2022]
Abstract
OBJECTIVE Prolonged fever-induced seizures (febrile status epilepticus [FSE]) during early childhood increase the risk for later epilepsy, but the underlying mechanisms are incompletely understood. Experimental FSE (eFSE) in rats successfully models human FSE, recapitulating the resulting epileptogenesis in a subset of affected individuals. However, the powerful viral and genetic tools that may enhance mechanistic insights into epileptogenesis and associated comorbidities, are better-developed for mice. Therefore, we aimed to determine if eFSE could be generated in mice and if it provoked enduring changes in hippocampal-network excitability and the development of spontaneous seizures. METHODS We employed C57BL/6J male mice, the strain used most commonly in transgenic manipulations, and examined if early life eFSE could be sustained and if it led to hyperexcitability of hippocampal networks and to epilepsy. Outcome measures included vulnerability to the subsequent administration of the limbic convulsant kainic acid (KA) and the development of spontaneous seizures. In the first mouse cohort, adult naive and eFSE-experiencing mice were exposed to KA. A second cohort of control and eFSE-experiencing young adult mice was implanted with bilateral hippocampal electrodes and recorded using continuous video-electroencephalography (EEG) for 2 to 3 months to examine for spontaneous seizures (epileptogenesis). RESULTS Induction of eFSE was feasible and eFSE increased the susceptibility of adult C57BL/6J mice to KA, thereby reducing latency to seizure onset and increasing seizure severity. Of 24 chronically recorded eFSE mice, 4 (16.5%) developed hippocampal epilepsy with a latent period of ~3 months, significantly different from the expectation by chance (P = .04). The limbic epilepsy that followed eFSE was progressive. SIGNIFICANCE eFSE promotes pro-epileptogenic network changes in a majority of C57BL/6J male mice and frank "temporal lobe-like" epilepsy in one sixth of the cohort. Mouse eFSE may thus provide a useful tool for investigating molecular, cellular, and circuit changes during the development of temporal lobe epilepsy and its comorbidities.
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Affiliation(s)
- Kevin D Chen
- Department of Pediatrics, University of California-Irvine, Irvine, CA, USA
| | - Alicia M Hall
- Department of Pediatrics, University of California-Irvine, Irvine, CA, USA
| | - Megan M Garcia-Curran
- Department of Anatomy & Neurobiology, University of California-Irvine, Irvine, CA, USA
| | - Gissell A Sanchez
- Department of Pediatrics, University of California-Irvine, Irvine, CA, USA
| | - Jennifer Daglian
- Department of Pediatrics, University of California-Irvine, Irvine, CA, USA
| | - Renhao Luo
- Department of Pediatrics, University of California-Irvine, Irvine, CA, USA
| | - Tallie Z Baram
- Department of Pediatrics, University of California-Irvine, Irvine, CA, USA.,Department of Anatomy & Neurobiology, University of California-Irvine, Irvine, CA, USA.,Department of Neurology, University of California-Irvine, Irvine, CA, USA
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31
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Joshi S, Goodkin HP. The Need to Intervene Before Time Point 2: Evidence From Clinical and Animal Data That Status Epilepticus Damages the Brain. J Clin Neurophysiol 2020; 37:375-380. [PMID: 32890057 DOI: 10.1097/wnp.0000000000000711] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Status epilepticus, a condition characterized by abnormally prolonged seizures, has the potential to cause irreversible, structural or functional, injury to the brain. Unfavorable consequences of these seizures include mortality, the risk of developing epilepsy, and cognitive impairment. We highlight key findings of clinical and laboratory studies that have provided insights into aspects of cell death, and anatomical and functional alterations triggered by status epilepticus that support the need to intervene before time point 2, the time after which the risk of these long-term consequences increases.
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Affiliation(s)
- Suchitra Joshi
- Department of Neurology, UVA Health, Charlottesville, Virginia, U.S.A
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Tiwari D, Schaefer TL, Schroeder-Carter LM, Krzeski JC, Bunk AT, Parkins EV, Snider A, Danzer R, Williams MT, Vorhees CV, Danzer SC, Gross C. The potassium channel Kv4.2 regulates dendritic spine morphology, electroencephalographic characteristics and seizure susceptibility in mice. Exp Neurol 2020; 334:113437. [PMID: 32822706 PMCID: PMC7642025 DOI: 10.1016/j.expneurol.2020.113437] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 08/13/2020] [Accepted: 08/17/2020] [Indexed: 01/21/2023]
Abstract
The voltage-gated potassium channel Kv4.2 is a critical regulator of dendritic excitability in the hippocampus and is crucial for dendritic signal integration. Kv4.2 mRNA and protein expression as well as function are reduced in several genetic and pharmacologically induced rodent models of epilepsy and autism. It is not known, however, whether reduced Kv4.2 is just an epiphenomenon or a disease-contributing cause of neuronal hyperexcitability and behavioral impairments in these neurological disorders. To address this question, we used male and female mice heterozygous for a Kv.2 deletion and adult-onset manipulation of hippocampal Kv4.2 expression in male mice to assess the role of Kv4.2 in regulating neuronal network excitability, morphology and anxiety-related behaviors. We observed a reduction in dendritic spine density and reduced proportions of thin and stubby spines but no changes in anxiety, overall activity, or retention of conditioned freezing memory in Kv4.2 heterozygous mice compared with wildtype littermates. Using EEG analyses, we showed elevated theta power and increased spike frequency in Kv4.2 heterozygous mice under basal conditions. In addition, the latency to onset of kainic acid-induced seizures was significantly shortened in Kv4.2 heterozygous mice compared with wildtype littermates, which was accompanied by a significant increase in theta power. By contrast, overexpressing Kv4.2 in wildtype mice through intrahippocampal injection of Kv4.2-expressing lentivirus delayed seizure onset and reduced EEG power. These results suggest that Kv4.2 is an important regulator of neuronal network excitability and dendritic spine morphology, but not anxiety-related behaviors. In the future, manipulation of Kv4.2 expression could be used to alter seizure susceptibility in epilepsy.
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Affiliation(s)
- Durgesh Tiwari
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA
| | - Tori L Schaefer
- Division of Psychiatry, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | | | - Joseph C Krzeski
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Alexander T Bunk
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Emma V Parkins
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Andrew Snider
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Reese Danzer
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Michael T Williams
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA
| | - Charles V Vorhees
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA
| | - Steve C Danzer
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA; Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA; Department of Anesthesiology, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
| | - Christina Gross
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA.
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Umpierre AD, Bystrom LL, Ying Y, Liu YU, Worrell G, Wu LJ. Microglial calcium signaling is attuned to neuronal activity in awake mice. eLife 2020; 9:56502. [PMID: 32716294 PMCID: PMC7402678 DOI: 10.7554/elife.56502] [Citation(s) in RCA: 102] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Accepted: 07/14/2020] [Indexed: 12/14/2022] Open
Abstract
Microglial calcium signaling underlies a number of key physiological and pathological processes in situ, but has not been studied in vivo in awake mice. Using multiple GCaMP6 variants targeted to microglia, we assessed how microglial calcium signaling responds to alterations in neuronal activity across a wide range. We find that only a small subset of microglial somata and processes exhibited spontaneous calcium transients in a chronic window preparation. However, hyperactive shifts in neuronal activity (kainate status epilepticus and CaMKIIa Gq DREADD activation) triggered increased microglial process calcium signaling, often concomitant with process extension. Additionally, hypoactive shifts in neuronal activity (isoflurane anesthesia and CaMKIIa Gi DREADD activation) also increased microglial process calcium signaling. Under hypoactive neuronal conditions, microglia also exhibited process extension and outgrowth with greater calcium signaling. Our work reveals that microglia have highly distinct microdomain signaling, and that processes specifically respond to bi-directional shifts in neuronal activity through increased calcium signaling.
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Affiliation(s)
| | | | - Yanlu Ying
- Department of Neurology, Mayo Clinic, Rochester, United States
| | - Yong U Liu
- Department of Neurology, Mayo Clinic, Rochester, United States
| | - Gregory Worrell
- Department of Neurology, Mayo Clinic, Rochester, United States
| | - Long-Jun Wu
- Department of Neurology, Mayo Clinic, Rochester, United States.,Department of Neuroscience, Mayo Clinic, Jacksonville, United States.,Department of Immunology, Mayo Clinic, Rochester, United States
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Gage M, Golden M, Putra M, Sharma S, Thippeswamy T. Sex as a biological variable in the rat model of diisopropylfluorophosphate-induced long-term neurotoxicity. Ann N Y Acad Sci 2020; 1479:44-64. [PMID: 32090337 DOI: 10.1111/nyas.14315] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 01/24/2020] [Accepted: 01/25/2020] [Indexed: 01/13/2023]
Abstract
Sex differences in response to neurotoxicant exposure that initiates epileptogenesis are understudied. We used telemetry-implanted male and female adult rats exposed to an organophosphate (OP) neurotoxicant, diisopropylflourophosphate (DFP), to test sex differences in the severity of status epilepticus (SE) and the development of spontaneous recurrent seizures (SRS). Females had significantly less severe SE and decreased epileptiform spikes compared with males, although females received a higher dose of DFP than males. The estrous stages had no impact on seizure susceptibility, but rats with severe SE had a significantly prolonged diestrus. A previously demonstrated disease-modifying agent, an inducible nitric oxide synthase inhibitor, 1400W, was tested in both sexes. None of the eight males treated with 1400W developed convulsive SRS during 4 weeks post-DFP exposure, while two of seven females developed convulsive SRS. Concerning gliosis and neurodegeneration, there were region-specific differences in the interaction between sex and SE severity. As SE severity influences epileptogenesis, and as females had significantly less severe SE, sex as a biological variable should be factored into the design of future OP nerve agent experiments while evaluating neurotoxicity and optimizing potential disease-modifying agents.
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Affiliation(s)
- Meghan Gage
- Epilepsy Research Laboratory, Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, Iowa
| | - Madison Golden
- Epilepsy Research Laboratory, Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, Iowa
| | - Marson Putra
- Epilepsy Research Laboratory, Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, Iowa
| | - Shaunik Sharma
- Epilepsy Research Laboratory, Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, Iowa
| | - Thimmasettappa Thippeswamy
- Epilepsy Research Laboratory, Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, Iowa
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Ibhazehiebo K, Rho JM, Kurrasch DM. Metabolism-based drug discovery in zebrafish: An emerging strategy to uncover new anti-seizure therapies. Neuropharmacology 2020; 167:107988. [PMID: 32070912 DOI: 10.1016/j.neuropharm.2020.107988] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Revised: 02/01/2020] [Accepted: 02/03/2020] [Indexed: 12/20/2022]
Abstract
As one of the most common neurological disorders, epilepsy can occur throughout the lifespan and from a multiplicity of causes, including genetic mutations, inflammation, neurotrauma, or brain malformations. Although pharmacological agents are the mainstay of treatment for seizure control, an unyielding 30-40% of patients remain refractory to these medications and continue to experience spontaneous recurrent seizures with attendant life-long cognitive, behavioural, and mental health issues, as well as an increased risk for sudden unexpected death. Despite over eight decades of antiseizure drug (ASD) discovery and the approval of dozens of new medications, the percentage of this refractory population remains virtually unchanged, suggesting that drugs with new and unexpected mechanisms of action are needed. In this brief review, we discuss the need for new animal models of epilepsy, with a particular focus on the advantages and disadvantages of zebrafish. We also outline the evidence that epilepsy is characterized by derangements in mitochondrial function and introduce the rationale and promise of bioenergetics as a functional readout assay to uncover novel ASDs. We also consider limitations of a zebrafish metabolism-based drug screening approach. Our goal is to discuss the opportunities and challenges of further development of mitochondrial screening strategies for the development of novel ASDs. This article is part of the special issue entitled 'New Epilepsy Therapies for the 21st Century - From Antiseizure Drugs to Prevention, Modification and Cure of Epilepsy'.
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Affiliation(s)
- Kingsley Ibhazehiebo
- Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Canada; Alberta Children's Hospital Research Institute, University of Calgary, Canada
| | - Jong M Rho
- Alberta Children's Hospital Research Institute, University of Calgary, Canada; Department of Pediatrics, Cumming School of Medicine, University of Calgary, Canada; Department of Neurosciences and Pediatrics, University of California San Diego, Rady Children's Hospital San Diego, California, USA
| | - Deborah M Kurrasch
- Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Canada; Alberta Children's Hospital Research Institute, University of Calgary, Canada.
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Upadhya D, Kodali M, Gitai D, Castro OW, Zanirati G, Upadhya R, Attaluri S, Mitra E, Shuai B, Hattiangady B, Shetty AK. A Model of Chronic Temporal Lobe Epilepsy Presenting Constantly Rhythmic and Robust Spontaneous Seizures, Co-morbidities and Hippocampal Neuropathology. Aging Dis 2019; 10:915-936. [PMID: 31595192 PMCID: PMC6764729 DOI: 10.14336/ad.2019.0720] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2019] [Accepted: 07/20/2019] [Indexed: 12/18/2022] Open
Abstract
Many animal prototypes illustrating the various attributes of human temporal lobe epilepsy (TLE) are available. These models have been invaluable for comprehending multiple epileptogenic processes, modifications in electrophysiological properties, neuronal hyperexcitability, neurodegeneration, neural plasticity, and chronic neuroinflammation in TLE. Some models have also uncovered the efficacy of new antiepileptic drugs or biologics for alleviating epileptogenesis, cognitive impairments, or spontaneous recurrent seizures (SRS). Nonetheless, the suitability of these models for testing candidate therapeutics in conditions such as chronic TLE is debatable because of a lower frequency of SRS and an inconsistent pattern of SRS activity over days, weeks or months. An ideal prototype of chronic TLE for investigating novel therapeutics would need to display a large number of SRS with a dependable frequency and severity and related co-morbidities. This study presents a new kainic acid (KA) model of chronic TLE generated through induction of status epilepticus (SE) in 6-8 weeks old male F344 rats. A rigorous characterization in the chronic epilepsy period validated that the animal prototype mimicked the most salient features of robust chronic TLE. Animals displayed a constant frequency and intensity of SRS across weeks and months in the 5th and 6th month after SE, as well as cognitive and mood impairments. Moreover, SRS frequency displayed a rhythmic pattern with 24-hour periodicity and a consistently higher number of SRS in the daylight period. Besides, the model showed many neuropathological features of chronic TLE, which include a partial loss of inhibitory interneurons, reduced neurogenesis with persistent aberrant migration of newly born neurons, chronic neuroinflammation typified by hypertrophied astrocytes and rod-shaped microglia, and a significant aberrant mossy fiber sprouting in the hippocampus. This consistent chronic seizure model is ideal for investigating the efficacy of various antiepileptic drugs and biologics as well as understanding multiple pathophysiological mechanisms underlying chronic epilepsy.
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Affiliation(s)
- Dinesh Upadhya
- Institute for Regenerative Medicine, Department of Molecular and Cellular Medicine, Texas A&M Health Science Center College of Medicine, College Station, TX, USA
| | - Maheedhar Kodali
- Institute for Regenerative Medicine, Department of Molecular and Cellular Medicine, Texas A&M Health Science Center College of Medicine, College Station, TX, USA
| | - Daniel Gitai
- Institute for Regenerative Medicine, Department of Molecular and Cellular Medicine, Texas A&M Health Science Center College of Medicine, College Station, TX, USA
| | - Olagide W Castro
- Institute for Regenerative Medicine, Department of Molecular and Cellular Medicine, Texas A&M Health Science Center College of Medicine, College Station, TX, USA
| | - Gabriele Zanirati
- Institute for Regenerative Medicine, Department of Molecular and Cellular Medicine, Texas A&M Health Science Center College of Medicine, College Station, TX, USA
| | - Raghavendra Upadhya
- Institute for Regenerative Medicine, Department of Molecular and Cellular Medicine, Texas A&M Health Science Center College of Medicine, College Station, TX, USA
| | - Sahithi Attaluri
- Institute for Regenerative Medicine, Department of Molecular and Cellular Medicine, Texas A&M Health Science Center College of Medicine, College Station, TX, USA
| | - Eeshika Mitra
- Institute for Regenerative Medicine, Department of Molecular and Cellular Medicine, Texas A&M Health Science Center College of Medicine, College Station, TX, USA
| | - Bing Shuai
- Institute for Regenerative Medicine, Department of Molecular and Cellular Medicine, Texas A&M Health Science Center College of Medicine, College Station, TX, USA
| | - Bharathi Hattiangady
- Institute for Regenerative Medicine, Department of Molecular and Cellular Medicine, Texas A&M Health Science Center College of Medicine, College Station, TX, USA
| | - Ashok K Shetty
- Institute for Regenerative Medicine, Department of Molecular and Cellular Medicine, Texas A&M Health Science Center College of Medicine, College Station, TX, USA
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Liu DC, Eagleman DE, Tsai NP. Novel roles of ER stress in repressing neural activity and seizures through Mdm2- and p53-dependent protein translation. PLoS Genet 2019; 15:e1008364. [PMID: 31557161 PMCID: PMC6762060 DOI: 10.1371/journal.pgen.1008364] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 08/08/2019] [Indexed: 12/30/2022] Open
Abstract
Seizures can induce endoplasmic reticulum (ER) stress, and sustained ER stress contributes to neuronal death after epileptic seizures. Despite the recent debate on whether inhibiting ER stress can reduce neuronal death after seizures, whether and how ER stress impacts neural activity and seizures remain unclear. In this study, we discovered that the acute ER stress response functions to repress neural activity through a protein translation-dependent mechanism. We found that inducing ER stress promotes the expression and distribution of murine double minute-2 (Mdm2) in the nucleus, leading to ubiquitination and down-regulation of the tumor suppressor p53. Reduction of p53 subsequently maintains protein translation, before the onset of translational repression seen during the latter phase of the ER stress response. Disruption of Mdm2 in an Mdm2 conditional knockdown (cKD) mouse model impairs ER stress-induced p53 down-regulation, protein translation, and reduction of neural activity and seizure severity. Importantly, these defects in Mdm2 cKD mice were restored by both pharmacological and genetic inhibition of p53 to mimic the inactivation of p53 seen during ER stress. Altogether, our study uncovered a novel mechanism by which neurons respond to acute ER stress. Further, this mechanism plays a beneficial role in reducing neural activity and seizure severity. These findings caution against inhibition of ER stress as a neuroprotective strategy for seizures, epilepsies, and other pathological conditions associated with excessive neural activity. One-third of epilepsy patients respond poorly to current anti-epileptic drugs. Thus, there is an urgent need to characterize cellular behavior during seizures, and the corresponding molecular mechanisms in order to develop better therapies. Seizures are known to induce ER stress but how the ER stress response functions to modulate seizure activity is unknown. Our study provides evidence to demonstrate a novel and beneficial role for the ER stress response in reducing neural activity and seizure severity. Mechanistically, we found that these beneficial effects are mediated by elevated protein translation, which is triggered by the activation of Mdm2-p53 signaling, during the early ER stress response. Our findings suggest that therapeutic attempts to reduce ER stress in epilepsies may result in worsening seizure activity and therefore caution against inhibition of ER stress as a neuroprotective strategy for epilepsies.
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Affiliation(s)
- Dai-Chi Liu
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Daphne E. Eagleman
- Department of Molecular and Integrative Physiology, School of Molecular and Cellular Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Nien-Pei Tsai
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
- Department of Molecular and Integrative Physiology, School of Molecular and Cellular Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
- * E-mail:
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Tiwari D, Brager DH, Rymer JK, Bunk AT, White AR, Elsayed NA, Krzeski JC, Snider A, Schroeder Carter LM, Danzer SC, Gross C. MicroRNA inhibition upregulates hippocampal A-type potassium current and reduces seizure frequency in a mouse model of epilepsy. Neurobiol Dis 2019; 130:104508. [PMID: 31212067 DOI: 10.1016/j.nbd.2019.104508] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 06/12/2019] [Accepted: 06/13/2019] [Indexed: 12/13/2022] Open
Abstract
Epilepsy is often associated with altered expression or function of ion channels. One example of such a channelopathy is the reduction of A-type potassium currents in the hippocampal CA1 region. The underlying mechanisms of reduced A-type channel function in epilepsy are unclear. Here, we show that inhibiting a single microRNA, miR-324-5p, which targets the pore-forming A-type potassium channel subunit Kv4.2, selectively increased A-type potassium currents in hippocampal CA1 pyramidal neurons in mice. Resting membrane potential, input resistance and other potassium currents were not altered. In a mouse model of acquired chronic epilepsy, inhibition of miR-324-5p reduced the frequency of spontaneous seizures and interictal epileptiform spikes supporting the physiological relevance of miR-324-5p-mediated control of A-type currents in regulating neuronal excitability. Mechanistic analyses demonstrated that microRNA-induced silencing of Kv4.2 mRNA is increased in epileptic mice leading to reduced Kv4.2 protein levels, which is mitigated by miR-324-5p inhibition. By contrast, other targets of miR-324-5p were unchanged. These results suggest a selective miR-324-5p-dependent mechanism in epilepsy regulating potassium channel function, hyperexcitability and seizures.
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Affiliation(s)
- Durgesh Tiwari
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Darrin H Brager
- Center for Learning and Memory, Department of Neuroscience, The University of Texas at Austin, Austin, TX 78712, USA
| | - Jeffrey K Rymer
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Alexander T Bunk
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Angela R White
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Nada A Elsayed
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Joseph C Krzeski
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Andrew Snider
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | | | - Steve C Danzer
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA; Department of Anesthesia, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA
| | - Christina Gross
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA.
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Tse K, Hammond D, Simpson D, Beynon RJ, Beamer E, Tymianski M, Salter MW, Sills GJ, Thippeswamy T. The impact of postsynaptic density 95 blocking peptide (Tat-NR2B9c) and an iNOS inhibitor (1400W) on proteomic profile of the hippocampus in C57BL/6J mouse model of kainate-induced epileptogenesis. J Neurosci Res 2019; 97:1378-1392. [PMID: 31090233 DOI: 10.1002/jnr.24441] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 04/23/2019] [Accepted: 04/24/2019] [Indexed: 12/22/2022]
Abstract
Antiepileptogenic agents that prevent the development of epilepsy following a brain insult remain the holy grail of epilepsy therapeutics. We have employed a label-free proteomic approach that allows quantification of large numbers of brain-expressed proteins in a single analysis in the mouse (male C57BL/6J) kainate (KA) model of epileptogenesis. In addition, we have incorporated two putative antiepileptogenic drugs, postsynaptic density protein-95 blocking peptide (PSD95BP or Tat-NR2B9c) and a highly selective inducible nitric oxide synthase inhibitor, 1400W, to give an insight into how such agents might ameliorate epileptogenesis. The test drugs were administered after the induction of status epilepticus (SE) and the animals were euthanized at 7 days, their hippocampi removed, and subjected to LC-MS/MS analysis. A total of 2,579 proteins were identified; their normalized abundance was compared between treatment groups using ANOVA, with correction for multiple testing by false discovery rate. Significantly altered proteins were subjected to gene ontology and KEGG pathway enrichment analyses. KA-induced SE was most robustly associated with an alteration in the abundance of proteins involved in neuroinflammation, including heat shock protein beta-1 (HSP27), glial fibrillary acidic protein, and CD44 antigen. Treatment with PSD95BP or 1400W moderated the abundance of several of these proteins plus that of secretogranin and Src substrate cortactin. Pathway analysis identified the glutamatergic synapse as a key target for both drugs. Our observations require validation in a larger-scale investigation, with candidate proteins explored in more detail. Nevertheless, this study has identified several mechanisms by which epilepsy might develop and several targets for novel drug development. OPEN PRACTICES: This article has been awarded Open Data. All materials and data are publicly accessible as supporting information. Learn more about the Open Practices badges from the Center for Open Science: https://osf.io/tvyxz/wiki.
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Affiliation(s)
- Karen Tse
- Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK
- Department of Molecular and Clinical Pharmacology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| | - Dean Hammond
- Department of Molecular and Cellular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| | - Deborah Simpson
- Centre for Proteome Research, Institute of Integrative Biology, University of Liverpool, Liverpool, UK
| | - Robert J Beynon
- Centre for Proteome Research, Institute of Integrative Biology, University of Liverpool, Liverpool, UK
| | - Edward Beamer
- Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK
| | - Michael Tymianski
- Department of Physiology and Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Michael W Salter
- Department of Physiology and Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Graeme J Sills
- Department of Molecular and Clinical Pharmacology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| | - Thimmasettappa Thippeswamy
- Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK
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40
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Putra M, Sharma S, Gage M, Gasser G, Hinojo-Perez A, Olson A, Gregory-Flores A, Puttachary S, Wang C, Anantharam V, Thippeswamy T. Inducible nitric oxide synthase inhibitor, 1400W, mitigates DFP-induced long-term neurotoxicity in the rat model. Neurobiol Dis 2019; 133:104443. [PMID: 30940499 DOI: 10.1016/j.nbd.2019.03.031] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 02/22/2019] [Accepted: 03/28/2019] [Indexed: 11/26/2022] Open
Abstract
Chemical nerve agents (CNA) are increasingly becoming a threat to both civilians and military personnel. CNA-induced acute effects on the nervous system have been known for some time and the long-term consequences are beginning to emerge. In this study, we used diisopropylfluorophosphate (DFP), a seizurogenic CNA to investigate the long-term impact of its acute exposure on the brain and its mitigation by an inducible nitric oxide synthase (iNOS) inhibitor, 1400W as a neuroprotectant in the rat model. Several experimental studies have demonstrated that DFP-induced seizures and/or status epilepticus (SE) causes permanent brain injury, even after the countermeasure medication (atropine, oxime, and diazepam). In the present study, DFP-induced SE caused a significant increase in iNOS and 3-nitrotyrosine (3-NT) at 24 h, 48 h, 7d, and persisted for a long-term (12 weeks post-exposure), which led to the hypothesis that iNOS is a potential therapeutic target in DFP-induced brain injury. To test the hypothesis, we administered 1400W (20 mg/kg, i.m.) or the vehicle twice daily for the first three days of post-exposure. 1400W significantly reduced DFP-induced iNOS and 3-NT upregulation in the hippocampus and piriform cortex, and the serum nitrite levels at 24 h post-exposure. 1400W also prevented DFP-induced mortality in <24 h. The brain immunohistochemistry (IHC) at 7d post-exposure revealed a significant reduction in gliosis and neurodegeneration (NeuN+ FJB positive cells) in the 1400W-treated group. 1400W, in contrast to the vehicle, caused a significant reduction in the epileptiform spiking and spontaneous recurrent seizures (SRS) during 12 weeks of continuous video-EEG study. IHC of brain sections from the same animals revealed a significant reduction in reactive gliosis (both microgliosis and astrogliosis) and neurodegeneration across various brain regions in the 1400W-treated group when compared to the vehicle-treated group. A multiplex assay from hippocampal lysates at 6 weeks post-exposure showed a significant increase in several key pro-inflammatory cytokines/chemokines such as IL-1α, TNFα, IL-1β, IL-2, IL-6, IL-12, IL-17a, MCP-1, LIX, and Eotaxin, and a growth factor, VEGF in the vehicle-treated animals. 1400W significantly suppressed IL-1α, TNFα, IL-2, IL-12, and MCP-1 levels. It also suppressed DFP-induced serum nitrite levels at 6 weeks post-exposure. In the Morris water maze, the vehicle-treated animals spent significantly less time in the target quadrant in a probe trial at 9d post-exposure compared to their time spent in the same quadrant 11 days previously (i.e., 2 days prior to DFP exposure). Such a difference was not observed in the 1400W and control groups. However, learning and short-term memory were unaffected when tested at 10-16d and 28-34d post-exposure. Accelerated rotarod, horizontal bar test, and the forced swim test revealed no significant changes between groups. Overall, the findings from this study suggest that 1400W may be considered as a potential therapeutic agent as a follow-on therapy for CNA exposure, after controlling the acute symptoms, to prevent mortality and some of the long-term neurotoxicity parameters such as epileptiform spiking, SRS, neurodegeneration, reactive gliosis in some brain regions, and certain key proinflammatory cytokines and chemokine.
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Affiliation(s)
- Marson Putra
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, United States
| | - Shaunik Sharma
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, United States
| | - Meghan Gage
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, United States
| | | | - Andy Hinojo-Perez
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, United States
| | - Ashley Olson
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, United States
| | - Adriana Gregory-Flores
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, United States
| | - Sreekanth Puttachary
- Department of Biomedical Sciences, Carlson College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331, United States
| | - Chong Wang
- Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, United States
| | | | - Thimmasettappa Thippeswamy
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, United States.
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Stereotypical patterns of epileptiform calcium signal in hippocampal CA1, CA3, dentate gyrus and entorhinal cortex in freely moving mice. Sci Rep 2019; 9:4518. [PMID: 30872744 PMCID: PMC6418290 DOI: 10.1038/s41598-019-41241-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Accepted: 03/04/2019] [Indexed: 11/08/2022] Open
Abstract
Epilepsy is a multi-etiological brain dysfunction syndrome. Hippocampal neuronal damage induced by seizures may be one of the causes leading to cognitive impairment, but the underlying mechanism remains to be further elucidated. The kainic acid (KA) model of temporal lobe epilepsy is widely used in understanding of the epileptogenesis. Fiber photometry is a signal detection technology suitable for recording calcium activity of neurons in the deep brain of freely moving animal. Here, we used the optical fiber-based method to monitor the real-time neuronal population activities of freely moving mice after subcutaneous injection of KA. We observed that KA administration led to one to three kinds of stereotypical patterns of epileptiform calcium activity in CA1, CA3, and dentate gyrus (DG) of the hippocampus, as well as the entorhinal cortex (EC). There were three kinds of waves in the hippocampal CA1, which we named wave 1, wave 2 and slow flash. Wave 1 and wave 2 appeared in both the CA3 and DG regions, but the EC only showed wave 1. In these epileptiform calcium signals, we observed a high amplitude and long duration calcium wave as a part of wave 2, which resembled cortical spreading depression (CSD) and always appeared at or after the end of seizure. Because the same characteristic of epileptiform calcium signal appeared in different brain regions, calcium signal may not exist with region specificity, but may exhibit a cell type specific manner. Thus, our work provides a support for the pathogenesis of epilepsy and epileptiform signal transmission research.
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Transition from status epilepticus to interictal spiking in a rodent model of mesial temporal epilepsy. Epilepsy Res 2019; 152:73-76. [PMID: 30913455 DOI: 10.1016/j.eplepsyres.2019.03.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 02/15/2019] [Accepted: 03/09/2019] [Indexed: 11/19/2022]
Abstract
Status epilepticus (SE) is a serious, life-threatening condition requiring immediate care to prevent neuronal injury and long-term functional deficits. SE is modeled in rodents by systemic injection of chemoconvulsants such as pilocarpine, which induces EEG and behavioral activities similar to what seen in humans. Combined injection of diazepam and ketamine is commonly used to terminate SE in rodents but, to date, no study has analysed the EEG activity and behavior during SE and after diazepam + ketamine administration. We therefore performed EEG recordings from the hippocampal CA3 region of mice before and during pilocarpine-induced SE as well as for 24 h after injection of diazepam + ketamine. We found that although convulsive behavior disappeared within 5.5 min ( ± 1.12 min; n = 5) after diazepam + ketamine treatment, EEG epileptiform activity resembling what seen during SE persisted up to 278.8 min ( ± 262.0 min). The end of this SE-like EEG pattern was characterised by transition to high amplitude, persisting interictal spikes. Our findings show that (i) administration of diazepam and ketamine stops behavioral but not EEG epileptiform activity associated to pilocarpine-induced SE; and (ii) such SE-like EEG pattern persists for approx. 4 h to be replaced by interictal spikes that predominate during the so called latent period in this model of mesial temporal lobe epilepsy.
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Marrero-Rosado B, de Araujo Furtado M, Schultz CR, Stone M, Kundrick E, Walker K, O'Brien S, Du F, Lumley LA. Soman-induced status epilepticus, epileptogenesis, and neuropathology in carboxylesterase knockout mice treated with midazolam. Epilepsia 2018; 59:2206-2218. [PMID: 30368799 PMCID: PMC6334636 DOI: 10.1111/epi.14582] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2018] [Revised: 09/21/2018] [Accepted: 09/24/2018] [Indexed: 12/31/2022]
Abstract
Objective Exposure to chemical warfare nerve agents (CWNAs), such as soman (GD), can induce status epilepticus (SE) that becomes refractory to benzodiazepines when treatment is delayed, leading to increased risk of epileptogenesis, severe neuropathology, and long‐term behavioral and cognitive deficits. Rodent models, widely used to evaluate novel medical countermeasures (MCMs) against CWNA exposure, normally express plasma carboxylesterase, an enzyme involved in the metabolism of certain organophosphorus compounds. To better predict the efficacy of novel MCMs against CWNA exposure in human casualties, it is crucial to use appropriate animal models that mirror the human condition. We present a comprehensive characterization of the seizurogenic, epileptogenic, and neuropathologic effects of GD exposure with delayed anticonvulsant treatment in the plasma carboxylesterase knockout (ES1−/−) mouse. Methods Electroencephalography (EEG) electrode‐implanted ES1−/− and wild‐type (C57BL/6) mice were exposed to various seizure‐inducing doses of GD, treated with atropine sulfate and the oxime HI‐6 at 1 minute after exposure, and administered midazolam at 15‐30 minutes following the onset of seizure activity. The latency of acute seizure onset and spontaneous recurrent seizures (SRS) was assessed, as were changes in EEG power spectra. At 2 weeks after GD exposure, neurodegeneration and neuroinflammation were assessed. Results GD‐exposed ES1−/− mice displayed a dose‐dependent response in seizure severity. Only ES1−/− mice exposed to the highest tested dose of GD developed SE, subchronic alterations in EEG power spectra, and SRS. Degree of neuronal cell loss and neuroinflammation were dose‐dependent; no significant neuropathology was observed in C57BL/6 mice or ES1−/− mice exposed to lower GD doses. Significance The US Food and Drug Administration (FDA) animal rule requires the use of relevant animal models for the advancement of MCMs against CWNAs. We present evidence that argues for the use of the ES1−/− mouse model to screen anticonvulsant, antiepileptic, and/or neuroprotective drugs against GD‐induced toxicity, as well as to identify mechanisms of GD‐induced epileptogenesis.
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Affiliation(s)
- Brenda Marrero-Rosado
- US Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland
| | | | - Caroline R Schultz
- US Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland
| | - Michael Stone
- US Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland
| | - Erica Kundrick
- US Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland
| | - Katie Walker
- US Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland
| | - Sean O'Brien
- US Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland
| | - Fu Du
- FD NeuroTechnologies, Columbia, Maryland
| | - Lucille A Lumley
- US Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland
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Valle-Dorado MG, Santana-Gómez CE, Orozco-Suárez SA, Rocha L. Sodium cromoglycate reduces short- and long-term consequences of status epilepticus in rats. Epilepsy Behav 2018; 87:200-206. [PMID: 30115604 DOI: 10.1016/j.yebeh.2018.06.021] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Revised: 05/18/2018] [Accepted: 06/14/2018] [Indexed: 01/03/2023]
Abstract
Several studies indicate that sodium cromoglycate (CG) induces neuroprotective effects in acute neurological conditions. The present study focused on investigating if the use of CG in rats during the post-status epilepticus (post-SE) period reduces the acute and long-term consequences of seizure activity. Our results revealed that animals that received a single dose of CG (50 mg/kg s.c.: subcutaneously) during the post-SE period showed a lower number of neurons in the process of dying in the dentate gyrus, hilus, cornu ammonis 1 (CA1), and CA3 of the dorsal hippocampus than the rats that received the vehicle. However, this effect was not evident in layers V-VI of the sensorimotor cortex or the lateral-posterior thalamic nucleus. A second experiment showed that animals that received CG subchronically (50 mg/kg s.c. every 12 h for 5 days followed by 24 mg/kg/day s.c. for 14 days using osmotic minipumps) after SE presented fewer generalized convulsive seizures and less neuronal damage in the lateral-posterior thalamic nucleus but not in the hippocampus or cortex. Our data indicate that CG can be used as a therapeutic strategy to reduce short- and long-term neuronal damage in the hippocampus and thalamus, respectively. The data also indicate that CG can reduce the expression of generalized convulsive spontaneous seizures when it is given during the latent period of epileptogenesis.
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Affiliation(s)
| | | | | | - Luisa Rocha
- Department of Pharmacobiology, Center of Research and Advanced Studies, Mexico City, Mexico.
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Barker-Haliski M, Harte-Hargrove LC, Ravizza T, Smolders I, Xiao B, Brandt C, Löscher W. A companion to the preclinical common data elements for pharmacologic studies in animal models of seizures and epilepsy. A Report of the TASK3 Pharmacology Working Group of the ILAE/AES Joint Translational Task Force. Epilepsia Open 2018; 3:53-68. [PMID: 30450485 PMCID: PMC6210039 DOI: 10.1002/epi4.12254] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Preclinical pharmacology studies in animal models of seizures and epilepsy have provided a platform to identify more than 20 antiseizure drugs in recent decades. To minimize variability in lab‐to‐lab studies and to harmonize approaches to data collection and reporting methodology in pharmacologic evaluations of the next generation of therapies, we present common data elements (CDEs), case report forms (CRFs), and this companion manuscript to help with the implementation of methods for studies in established preclinical seizure and epilepsy models in adult rodents. The development of and advocacy for CDEs in preclinical research has been encouraged previously by both clinical and preclinical groups. It is anticipated that adoption and implementation of these CDEs in preclinical studies may help standardize approaches to minimize variability and increase the reproducibility of preclinical studies. Moreover, they may provide a methodologic framework for pharmacology studies in atypical animal models or models in development, which may ultimately promote novel therapy development. In the present document, we refer selectively to animal models that have a long history of preclinical use, and in some cases, are clinically validated.
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Affiliation(s)
- Melissa Barker-Haliski
- Department of Pharmacy School of Pharmacy University of Washington Seattle Washington U.S.A
| | - Lauren C Harte-Hargrove
- ILAE/AES Joint Translational Task Force International League Against Epilepsy West Hartford Connecticut U.S.A
| | - Teresa Ravizza
- Department of Neuroscience IRCCS-Institute for Pharmacological Research Mario Negri Milan Italy
| | - Ilse Smolders
- Department of Pharmaceutical Chemistry Drug Analysis and Drug Information Center for Neurosciences Vrije Universiteit Brussel Brussels Belgium
| | - Bo Xiao
- Department of Neurology Xiangya Hospital Central South University Changsha China
| | - Claudia Brandt
- Department of Pharmacology, Toxicology, and Pharmacy University of Veterinary Medicine Hannover Hannover Germany.,Center for Systems Neuroscience Hannover Germany
| | - Wolfgang Löscher
- Department of Pharmacology, Toxicology, and Pharmacy University of Veterinary Medicine Hannover Hannover Germany.,Center for Systems Neuroscience Hannover Germany
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Chemaly N, Nehlig A, Chiron C, Nabbout R. Electrocorticographic telemetric recording in unrestrained mouse pups. J Neurosci Methods 2018; 305:17-27. [DOI: 10.1016/j.jneumeth.2018.04.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Revised: 04/30/2018] [Accepted: 04/30/2018] [Indexed: 10/17/2022]
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Smith ZZ, Benison AM, Bercum FM, Dudek FE, Barth DS. Progression of convulsive and nonconvulsive seizures during epileptogenesis after pilocarpine-induced status epilepticus. J Neurophysiol 2018; 119:1818-1835. [PMID: 29442558 DOI: 10.1152/jn.00721.2017] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Although convulsive seizures occurring during pilocarpine-induced epileptogenesis have received considerable attention, nonconvulsive seizures have not been closely examined, even though they may reflect the earliest signs of epileptogenesis and potentially guide research on antiepileptogenic interventions. The definition of nonconvulsive seizures based on brain electrical activity alone has been controversial. Here we define and quantify electrographic properties of convulsive and nonconvulsive seizures in the context of the acquired epileptogenesis that occurs after pilocarpine-induced status epilepticus (SE). Lithium-pilocarpine was used to induce the prolonged repetitive seizures characteristic of SE; when SE was terminated with paraldehyde, seizures returned during the 2-day period after pilocarpine treatment. A distinct latent period ranging from several days to >2 wk was then measured with continuous, long-term video-EEG. Nonconvulsive seizures dominated the onset of epileptogenesis and consistently preceded the first convulsive seizures but were still present later. Convulsive and nonconvulsive seizures had similar durations. Postictal depression (background suppression of the EEG) lasted for >100 s after both convulsive and nonconvulsive seizures. Principal component analysis was used to quantify the spectral evolution of electrical activity that characterized both types of spontaneous recurrent seizures. These studies demonstrate that spontaneous nonconvulsive seizures have electrographic properties similar to convulsive seizures and confirm that nonconvulsive seizures link the latent period and the onset of convulsive seizures during post-SE epileptogenesis in an animal model. Nonconvulsive seizures may also reflect the earliest signs of epileptogenesis in human acquired epilepsy, when intervention could be most effective. NEW & NOTEWORTHY Nonconvulsive seizures usually represent the first bona fide seizure following a latent period, dominate the early stages of epileptogenesis, and change in severity in a manner consistent with the progressive nature of epileptogenesis. This analysis demonstrates that nonconvulsive and convulsive seizures have different behavioral outcomes but similar electrographic signatures. Alternatively, epileptiform spike-wave discharges fail to recapitulate several key seizure features and represent a category of electrical activity separate from nonconvulsive seizures in this model.
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Affiliation(s)
- Zachariah Z Smith
- Department of Psychology and Neuroscience, University of Colorado , Boulder, Colorado
| | - Alexander M Benison
- Department of Psychology and Neuroscience, University of Colorado , Boulder, Colorado
| | - Florencia M Bercum
- Department of Psychology and Neuroscience, University of Colorado , Boulder, Colorado
| | - F Edward Dudek
- Department of Neurosurgery, University of Utah School of Medicine , Salt Lake City, Utah
| | - Daniel S Barth
- Department of Psychology and Neuroscience, University of Colorado , Boulder, Colorado
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Sharma S, Carlson S, Puttachary S, Sarkar S, Showman L, Putra M, Kanthasamy AG, Thippeswamy T. Role of the Fyn-PKCδ signaling in SE-induced neuroinflammation and epileptogenesis in experimental models of temporal lobe epilepsy. Neurobiol Dis 2018; 110:102-121. [PMID: 29197620 PMCID: PMC5753797 DOI: 10.1016/j.nbd.2017.11.008] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2017] [Revised: 11/08/2017] [Accepted: 11/27/2017] [Indexed: 02/07/2023] Open
Abstract
Status epilepticus (SE) induces neuroinflammation and epileptogenesis, but the mechanisms are not yet fully delineated. The Fyn, a non-receptor Src family tyrosine kinase (SFK), and its immediate downstream target, PKCδ are emerging as potential mediators of neuroinflammation. In order to first determine the role of Fyn kinase signaling in SE, we tested the efficacy of a SFK inhibitor, saracatinib (25mg/kg, oral) in C57BL/6J mouse kainate model of acute seizures. Saracatinib pretreatment dampened SE severity and completely prevented mortality. We further utilized fyn-/- and fyn+/+ mice (wildtype control for the fyn-/- mice on same genetic background), and the rat kainate model, treated with saracatinib post-SE, to validate the role of Fyn/SFK in SE and epileptogenesis. We observed significant reduction in SE severity, epileptiform spikes, and electrographic non-convulsive seizures in fyn-/- mice when compared to fyn+/+ mice. Interestingly, significant reductions in phosphorylated pSrc-416 and PKCδ (pPKCδ-507) and naive PKCδ were observed in fyn-/- mice as compared to fyn+/+ mice suggesting that PKCδ signaling is a downstream mediator of Fyn in SE and epileptogenesis. Notably, fyn-/- mice also showed a reduction in key proinflammatory mediators TNF-α, IL-1β, and iNOS mRNA expression; serum IL-6 and IL-12 levels; and nitro-oxidative stress markers such as 4-HNE, gp91phox, and 3-NT in the hippocampus. Immunohistochemistry revealed a significant increase in reactive microgliosis and neurodegeneration in the hippocampus and hilus of dentate gyrus in fyn+/+ mice in contrast to fyn-/- mice. Interestingly, we did not observe upregulation of Fyn in pyramidal neurons of the hippocampus during post-SE in fyn+/+ mice, but it was upregulated in hilar neurons of the dentate gyrus when compared to naïve control. In reactive microglia, both Fyn and PKCδ were persistently upregulated during post-SE suggesting that Fyn-PKCδ may drive neuroinflammation during epileptogenesis. Since disabling the Fyn kinase prior to SE, either by treating with saracatinib or fyn gene knockout, suppressed seizures and the subsequent epileptogenic events, we further tested whether Fyn/SFK inhibition during post-SE modifies epileptogenesis. Telemetry-implanted, SE-induced, rats were treated with saracatinib and continuously monitored for a month. At 2h post-diazepam, the saracatinib (25mg/kg) or the vehicle was administered orally and repeated twice daily for first three days followed by a single dose/day for the next four days. The saracatinib post-treatment prevented epileptogenesis in >50% of the rats and significantly reduced spontaneous seizures and epileptiform spikes in the rest (one animal did not respond) when compared to the vehicle treated group, which had >24 seizures in a month. Collectively, the findings suggest that Fyn/SFK is a potential mediator of epileptogenesis and a therapeutic target to prevent/treat seizures and epileptogenesis.
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Affiliation(s)
- Shaunik Sharma
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames 50011, USA
| | - Steven Carlson
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames 50011, USA
| | - Sreekanth Puttachary
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames 50011, USA
| | - Souvarish Sarkar
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames 50011, USA
| | - Lucas Showman
- W.M. Keck Metabolomics Research Laboratory, Iowa State University, Ames 50011, USA
| | - Marson Putra
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames 50011, USA
| | - Anumantha G Kanthasamy
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames 50011, USA
| | - Thimmasettappa Thippeswamy
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames 50011, USA.
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Sharma S, Puttachary S, Thippeswamy A, Kanthasamy AG, Thippeswamy T. Status Epilepticus: Behavioral and Electroencephalography Seizure Correlates in Kainate Experimental Models. Front Neurol 2018; 9:7. [PMID: 29410648 PMCID: PMC5787145 DOI: 10.3389/fneur.2018.00007] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 01/03/2018] [Indexed: 01/11/2023] Open
Abstract
Various etiological factors, such as head injury, chemical intoxication, tumors, and gene mutation, can induce epileptogenesis. In animal models, status epilepticus (SE) triggers epileptogenesis. In humans, convulsive SE for >30 min can be a life-threatening medical emergency. The duration and severity of convulsive SE are highly variable in chemoconvulsant animal models. A continuous video-electroencephalography (EEG) recording, and/or diligent direct observation, facilitates quantification of exact duration of different stages of convulsive seizures (Racine stages 3–5) to determine the severity of SE. A continuous convulsive SE for >30 min usually causes high mortality in some rodents and results in widespread brain damage in the surviving animals, in spite of treating with antiepileptic drugs (AEDs). AEDs control behavioral seizures but not EEG seizures. The severity of initial SE impacts epileptogenesis and cognitive function; therefore, quantitative assessment of behavioral SE and EEG in animal models will help to understand the impact of SE severity on epileptogenesis. There are several excellent reviews on experimental models of seizure/SE/epilepsy. This review focusses on the comparison of induction and characterization of behavioral SE and EEG correlates in mice and rats induced by kainate. We also discuss the advantages of repeated low dose of kainate (i.p. route), which minimizes variability in the initial SE severity between animals and reduces mortality rate. A refined approach to induce SE with kainate also addresses the two of the 3Rs (i.e., refinement and reduction), the guiding principles for ethical and scientific standpoint of animal research.
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Affiliation(s)
- Shaunik Sharma
- Epilepsy Research Laboratory, Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, United States
| | - Sreekanth Puttachary
- Veterinary Biomedical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, OR, United States
| | - Achala Thippeswamy
- Epilepsy Research Laboratory, Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, United States
| | - Anumantha G Kanthasamy
- Parkinson's Research Laboratory, Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, United States
| | - Thimmasettappa Thippeswamy
- Epilepsy Research Laboratory, Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, United States
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Sharma S, Puttachary S, Thippeswamy T. Glial source of nitric oxide in epileptogenesis: A target for disease modification in epilepsy. J Neurosci Res 2017; 97:1363-1377. [PMID: 29230865 DOI: 10.1002/jnr.24205] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 10/31/2017] [Accepted: 11/20/2017] [Indexed: 12/11/2022]
Abstract
Epileptogenesis is the process of developing an epileptic condition and/or its progression once it is established. The molecules that initiate, promote, and propagate remarkable changes in the brain during epileptogenesis are emerging as targets for prevention/treatment of epilepsy. Epileptogenesis is a continuous process that follows immediately after status epilepticus (SE) in animal models of acquired temporal lobe epilepsy (TLE). Both SE and epileptogenesis are potential therapeutic targets for the discovery of anticonvulsants and antiepileptogenic or disease-modifying agents. For translational studies, SE targets are appropriate for screening anticonvulsive drugs prior to their advancement as therapeutic agents, while targets of epileptogenesis are relevant for identification and development of therapeutic agents that can either prevent or modify the disease or its onset. The acute seizure models do not reveal antiepileptogenic properties of anticonvulsive drugs. This review highlights the important components of epileptogenesis and the long-term impact of intervening one of these components, nitric oxide (NO), in rat and mouse kainate models of TLE. NO is a putative pleotropic gaseous neurotransmitter and an important contributor of nitro-oxidative stress that coexists with neuroinflammation and epileptogenesis. The long-term impact of inhibiting the glial source of NO during early epileptogenesis in the rat model of TLE is reviewed. The importance of sex as a biological variable in disease modification strategies in epilepsy is also briefly discussed.
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Affiliation(s)
- Shaunik Sharma
- Epilepsy Research Laboratory, Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, Iowa
| | | | - Thimmasettappa Thippeswamy
- Epilepsy Research Laboratory, Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, Iowa
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