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Dezsi G, Ozturk E, Wong D, Hudson MR, Martello G, Gomes FMM, Salzberg MR, Morris MJ, O'Brien TJ, Jones NC. Fluoxetine accelerates epileptogenesis and magnifies disease severity in a rat model of acquired epilepsy. Epilepsia 2024. [PMID: 39102253 DOI: 10.1111/epi.18080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 07/17/2024] [Accepted: 07/22/2024] [Indexed: 08/06/2024]
Abstract
OBJECTIVE Many people with epilepsy experience comorbid anxiety and depression, and antidepressants remain a primary treatment for this. Emerging evidence suggests that these agents may modulate epileptogenesis to influence disease severity. Here, we assessed how treatment with the selective serotonin reuptake inhibitor (SSRI) antidepressant fluoxetine impacts epileptogenic, behavioral, and pathological sequelae following status epilepticus. METHODS Male Wistar rats received kainic acid to induce status epilepticus (SE) or vehicle (sham). Animals then received either fluoxetine (10 mg/kg/day) or vehicle for 8 weeks via subcutaneous osmotic pump. Video-electroencephalography was recorded continuously until behavioral testing at day 56, including assessments of anxiety- and depression-like behavior and spatial cognition. Postmortem immunocytochemistry studies examined mossy fiber sprouting. RESULTS Fluoxetine treatment significantly accelerated epileptogenesis following SE, reducing the average period to the first spontaneous seizure (from 32 days [vehicle] to 6 days [fluoxetine], p < .01). Also, fluoxetine exposure magnified the severity of the resultant epilepsy, increasing seizure frequency compared to vehicle (p < .01). Exposure to fluoxetine was associated with improved anxiety- and depression-like behaviors but significantly worsened cognition. Mossy fiber sprouting was more pronounced in fluoxetine-treated rats compared to vehicle (p < .0001). SIGNIFICANCE Our studies demonstrate that, using a model exhibiting spontaneous seizures, epileptogenesis is accelerated and magnified by fluoxetine, an effect that may be related to more severe pathological neuroplasticity. The differential influence of fluoxetine on behavior indicates that different circuitry and mechanisms are responsible for these comorbidities. These findings suggest that caution should be exercised when prescribing SSRI antidepressants to people at risk of developing epilepsy.
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Affiliation(s)
- Gabi Dezsi
- Department of Neuroscience, School of Translational Medicine, Monash University and Department of Neurology, Alfred Hospital, Melbourne, Victoria, Australia
- Department of Medicine (Royal Melbourne Hospital), University of Melbourne, Melbourne Brain Centre, Parkville, Victoria, Australia
| | - Ezgi Ozturk
- Department of Neuroscience, School of Translational Medicine, Monash University and Department of Neurology, Alfred Hospital, Melbourne, Victoria, Australia
- Department of Medicine (Royal Melbourne Hospital), University of Melbourne, Melbourne Brain Centre, Parkville, Victoria, Australia
| | - Davy Wong
- Department of Medicine (Royal Melbourne Hospital), University of Melbourne, Melbourne Brain Centre, Parkville, Victoria, Australia
| | - Matthew R Hudson
- Department of Neuroscience, School of Translational Medicine, Monash University and Department of Neurology, Alfred Hospital, Melbourne, Victoria, Australia
| | - Gabriella Martello
- Department of Neuroscience, School of Translational Medicine, Monash University and Department of Neurology, Alfred Hospital, Melbourne, Victoria, Australia
| | - Flavia M M Gomes
- Department of Neuroscience, School of Translational Medicine, Monash University and Department of Neurology, Alfred Hospital, Melbourne, Victoria, Australia
| | - Michael R Salzberg
- Department of Medicine (Royal Melbourne Hospital), University of Melbourne, Melbourne Brain Centre, Parkville, Victoria, Australia
| | - Margaret J Morris
- Department of Pharmacology, School of Biomedical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Terence J O'Brien
- Department of Neuroscience, School of Translational Medicine, Monash University and Department of Neurology, Alfred Hospital, Melbourne, Victoria, Australia
- Department of Medicine (Royal Melbourne Hospital), University of Melbourne, Melbourne Brain Centre, Parkville, Victoria, Australia
| | - Nigel C Jones
- Department of Neuroscience, School of Translational Medicine, Monash University and Department of Neurology, Alfred Hospital, Melbourne, Victoria, Australia
- Department of Medicine (Royal Melbourne Hospital), University of Melbourne, Melbourne Brain Centre, Parkville, Victoria, Australia
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Guo D, Han L, Godale CM, Rensing NR, Danzer SC, Wong M. A role of dentate gyrus mechanistic target of rapamycin activation in epileptogenesis in a mouse model of posttraumatic epilepsy. Epilepsia 2024; 65:2127-2137. [PMID: 38761065 PMCID: PMC11251851 DOI: 10.1111/epi.18011] [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: 01/28/2024] [Revised: 04/30/2024] [Accepted: 04/30/2024] [Indexed: 05/20/2024]
Abstract
OBJECTIVE The mechanistic target of rapamycin (mTOR) pathway has been implicated in promoting epileptogenesis in animal models of acquired epilepsy, such as posttraumatic epilepsy (PTE) following traumatic brain injury (TBI). However, the specific anatomical regions and neuronal populations mediating mTOR's role in epileptogenesis are not well defined. In this study, we tested the hypothesis that mTOR activation in dentate gyrus granule cells promotes neuronal death, mossy fiber sprouting, and PTE in the controlled cortical impact (CCI) model of TBI. METHODS An adeno-associated virus (AAV)-Cre viral vector was injected into the hippocampus of Rptorflox/flox (regulatory-associated protein of mTOR) mutant mice to inhibit mTOR activation in dentate gyrus granule cells. Four weeks after AAV-Cre or AAV-vehicle injection, mice underwent CCI injury and were subsequently assessed for mTOR pathway activation by Western blotting, neuronal death, and mossy fiber sprouting by immunopathological analysis, and posttraumatic seizures by video-electroencephalographic monitoring. RESULTS AAV-Cre injection primarily affected the dentate gyrus and inhibited hippocampal mTOR activation following CCI injury. AAV-Cre-injected mice had reduced neuronal death in dentate gyrus detected by Fluoro-Jade B staining and decreased mossy fiber sprouting by ZnT3 immunostaining. Finally, AAV-Cre-injected mice exhibited a decrease in incidence of PTE. SIGNIFICANCE mTOR pathway activation in dentate gyrus granule cells may at least partly mediate pathological abnormalities and epileptogenesis in models of TBI and PTE. Targeted modulation of mTOR activity in this hippocampal network may represent a focused therapeutic approach for antiepileptogenesis and prevention of PTE.
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Affiliation(s)
- Dongjun Guo
- Department of Neurology and the Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, USA 63110
| | - Lirong Han
- Department of Neurology and the Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, USA 63110
| | - Christin M. Godale
- Department of Anesthesia, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229
| | - Nicholas R. Rensing
- Department of Neurology and the Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, USA 63110
| | - Steve C. Danzer
- Department of Anesthesia, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229
| | - Michael Wong
- Department of Neurology and the Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, USA 63110
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Ali NH, Al-Kuraishy HM, Al-Gareeb AI, Alnaaim SA, Hetta HF, Saad HM, Batiha GES. A Mutual Nexus Between Epilepsy and α-Synuclein: A Puzzle Pathway. Mol Neurobiol 2024:10.1007/s12035-024-04204-6. [PMID: 38703341 DOI: 10.1007/s12035-024-04204-6] [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: 07/01/2023] [Accepted: 04/12/2024] [Indexed: 05/06/2024]
Abstract
Alpha-synuclein (α-Syn) is a specific neuronal protein that regulates neurotransmitter release and trafficking of synaptic vesicles. Exosome-associated α-Syn which is specific to the central nervous system (CNS) is involved in the pathogenesis of epilepsy. Therefore, this review aimed to elucidate the possible link between α-Syn and epilepsy, and how it affects the pathophysiology of epilepsy. A neurodegenerative protein such as α-Syn is implicated in the pathogenesis of epilepsy. Evidence from preclinical and clinical studies revealed that upregulation of α-Syn induces progressive neuronal dysfunctions through induction of oxidative stress, neuroinflammation, and inhibition of autophagy in a vicious cycle with subsequent development of severe epilepsy. In addition, accumulation of α-Syn in epilepsy could be secondary to the different cellular alterations including oxidative stress, neuroinflammation, reduction of brain-derived neurotrophic factor (BDNF) and progranulin (PGN), and failure of the autophagy pathway. However, the mechanism of α-Syn-induced-epileptogenesis is not well elucidated. Therefore, α-Syn could be a secondary consequence of epilepsy. Preclinical and clinical studies are warranted to confirm this causal relationship.
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Affiliation(s)
- Naif H Ali
- Department of Internal Medicine, Medical College, Najran University, Najran, Kingdom of Saudi Arabia
| | - Hayder M Al-Kuraishy
- Department of Clinical Pharmacology and Medicine, College of Medicine, Mustansiriyah University, M.B.Ch.B, FRCP, P.O. Box 14132, Baghdad, Iraq
| | - Ali I Al-Gareeb
- Jabir Ibn Hayyan Medical University, Al-Ameer Qu, P.O. Box 13, Kufa, Najaf, Iraq
| | - Saud A Alnaaim
- Clinical Neurosciences Department, College of Medicine, King Faisal University, Hofuf, Saudi Arabia
| | - Helal F Hetta
- Department of Medical Microbiology and Immunology, Faculty of Medicine, Assiut University, Assiut, 71515, Egypt
| | - Hebatallah M Saad
- Department of Pathology, Faculty of Veterinary Medicine, Matrouh University, Matrouh, 51744, Egypt.
| | - Gaber El-Saber Batiha
- Department of Pharmacology and Therapeutics, Faculty of Veterinary Medicine, Damanhour University, Damanhour, 22511, AlBeheira, Egypt.
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Blair RE, Hawkins E, Pinchbeck LR, DeLorenzo RJ, Deshpande LS. Chronic Epilepsy and Mossy Fiber Sprouting Following Organophosphate-Induced Status Epilepticus in Rats. J Pharmacol Exp Ther 2024; 388:325-332. [PMID: 37643794 PMCID: PMC10801751 DOI: 10.1124/jpet.123.001739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 07/20/2023] [Accepted: 07/24/2023] [Indexed: 08/31/2023] Open
Abstract
Organophosphate (OP) compounds are highly toxic and include pesticides and chemical warfare nerve agents. OP exposure inhibits the acetylcholinesterase enzyme, causing cholinergic overstimulation that can evolve into status epilepticus (SE) and produce lethality. Furthermore, OP-induced SE survival is associated with mood and memory dysfunction and spontaneous recurrent seizures (SRS). In male Sprague-Dawley rats, we assessed hippocampal pathology and chronic SRS following SE induced by administration of OP agents paraoxon (2 mg/kg, s.c.), diisopropyl fluorophosphate (4 mg/kg, s.c.), or O-isopropyl methylphosphonofluoridate (GB; sarin) (2 mg/kg, s.c.), immediately followed by atropine and 2-PAM. At 1-hour post-OP-induced SE onset, midazolam was administered to control SE. Approximately 6 months after OP-induced SE, SRS were evaluated using video and electroencephalography monitoring. Histopathology was conducted using hematoxylin and eosin (H&E), while silver sulfide (Timm) staining was used to assess mossy fiber sprouting (MFS). Across all the OP agents, over 60% of rats that survived OP-induced SE developed chronic SRS. H&E staining revealed a significant hippocampal neuronal loss, while Timm staining revealed extensive MFS within the inner molecular region of the dentate gyrus. This study demonstrates that OP-induced SE is associated with hippocampal neuronal loss, extensive MFS, and the development of SRS, all hallmarks of chronic epilepsy. SIGNIFICANCE STATEMENT: Models of organophosphate (OP)-induced SE offer a unique resource to identify molecular mechanisms contributing to neuropathology and the development of chronic OP morbidities. These models could allow the screening of targeted therapeutics for efficacious treatment strategies for OP toxicities.
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Affiliation(s)
- Robert E Blair
- Departments of Neurology (R.E.B., E.H., R.J.D., L.S.D.) and Pharmacology and Toxicology (R.J.D., L.S.D.) School of Medicine, and Department of Biology, College of Humanities & Sciences (L.R.P.), Virginia Commonwealth University, Richmond, Virginia
| | - Elisa Hawkins
- Departments of Neurology (R.E.B., E.H., R.J.D., L.S.D.) and Pharmacology and Toxicology (R.J.D., L.S.D.) School of Medicine, and Department of Biology, College of Humanities & Sciences (L.R.P.), Virginia Commonwealth University, Richmond, Virginia
| | - Lauren R Pinchbeck
- Departments of Neurology (R.E.B., E.H., R.J.D., L.S.D.) and Pharmacology and Toxicology (R.J.D., L.S.D.) School of Medicine, and Department of Biology, College of Humanities & Sciences (L.R.P.), Virginia Commonwealth University, Richmond, Virginia
| | - Robert J DeLorenzo
- Departments of Neurology (R.E.B., E.H., R.J.D., L.S.D.) and Pharmacology and Toxicology (R.J.D., L.S.D.) School of Medicine, and Department of Biology, College of Humanities & Sciences (L.R.P.), Virginia Commonwealth University, Richmond, Virginia
| | - Laxmikant S Deshpande
- Departments of Neurology (R.E.B., E.H., R.J.D., L.S.D.) and Pharmacology and Toxicology (R.J.D., L.S.D.) School of Medicine, and Department of Biology, College of Humanities & Sciences (L.R.P.), Virginia Commonwealth University, Richmond, Virginia
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Sri Hari A, Banerji R, Liang LP, Fulton RE, Huynh CQ, Fabisiak T, McElroy PB, Roede JR, Patel M. Increasing glutathione levels by a novel posttranslational mechanism inhibits neuronal hyperexcitability. Redox Biol 2023; 67:102895. [PMID: 37769522 PMCID: PMC10539966 DOI: 10.1016/j.redox.2023.102895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 09/14/2023] [Accepted: 09/18/2023] [Indexed: 10/02/2023] Open
Abstract
Glutathione (GSH) depletion, and impaired redox homeostasis have been observed in experimental animal models and patients with epilepsy. Pleiotropic strategies that elevate GSH levels via transcriptional regulation have been shown to significantly decrease oxidative stress and seizure frequency, increase seizure threshold, and rescue certain cognitive deficits. Whether elevation of GSH per se alters neuronal hyperexcitability remains unanswered. We previously showed that thiols such as dimercaprol (DMP) elevate GSH via post-translational activation of glutamate cysteine ligase (GCL), the rate limiting GSH biosynthetic enzyme. Here, we asked if elevation of cellular GSH by DMP altered neuronal hyperexcitability in-vitro and in-vivo. Treatment of primary neuronal-glial cerebrocortical cultures with DMP elevated GSH and inhibited a voltage-gated potassium channel blocker (4-aminopyridine, 4AP) induced neuronal hyperexcitability. DMP increased GSH in wildtype (WT) zebrafish larvae and significantly attenuated convulsant pentylenetetrazol (PTZ)-induced acute 'seizure-like' swim behavior. DMP treatment increased GSH and inhibited convulsive, spontaneous 'seizure-like' swim behavior in the Dravet Syndrome (DS) zebrafish larvae (scn1Lab). Furthermore, DMP treatment significantly decreased spontaneous electrographic seizures and associated seizure parameters in scn1Lab zebrafish larvae. We investigated the role of the redox-sensitive mammalian target of rapamycin (mTOR) pathway due to the presence of several cysteine-rich proteins and their involvement in regulating neuronal excitability. Treatment of primary neuronal-glial cerebrocortical cultures with 4AP or l-buthionine-(S,R)-sulfoximine (BSO), an irreversible inhibitor of GSH biosynthesis, significantly increased mTOR complex I (mTORC1) activity which was rescued by pre-treatment with DMP. Furthermore, BSO-mediated GSH depletion oxidatively modified the tuberous sclerosis protein complex (TSC) consisting of hamartin (TSC1), tuberin (TSC2), and TBC1 domain family member 7 (TBC1D7) which are critical negative regulators of mTORC1. In summary, our results suggest that DMP-mediated GSH elevation by a novel post-translational mechanism can inhibit neuronal hyperexcitability both in-vitro and in-vivo and a plausible link is the redox sensitive mTORC1 pathway.
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Affiliation(s)
- Ashwini Sri Hari
- Department of Pharmaceutical Sciences, University of Colorado, Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Rajeswari Banerji
- Department of Pharmaceutical Sciences, University of Colorado, Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Li-Ping Liang
- Department of Pharmaceutical Sciences, University of Colorado, Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Ruth E Fulton
- Department of Pharmaceutical Sciences, University of Colorado, Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Christopher Quoc Huynh
- Department of Pharmaceutical Sciences, University of Colorado, Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Timothy Fabisiak
- Department of Pharmaceutical Sciences, University of Colorado, Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Pallavi Bhuyan McElroy
- The Janssen Pharmaceutical Companies of Johnson & Johnson, Greater Philadelphia Area, Horsham, PA, 19044, USA
| | - James R Roede
- Department of Pharmaceutical Sciences, University of Colorado, Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Manisha Patel
- Department of Pharmaceutical Sciences, University of Colorado, Anschutz Medical Campus, Aurora, CO, 80045, USA.
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Łukasiuk K, Lasoń W. Emerging Molecular Targets for Anti-Epileptogenic and Epilepsy Modifying Drugs. Int J Mol Sci 2023; 24:ijms24032928. [PMID: 36769250 PMCID: PMC9917847 DOI: 10.3390/ijms24032928] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 01/27/2023] [Accepted: 01/31/2023] [Indexed: 02/05/2023] Open
Abstract
The pharmacological treatment of epilepsy is purely symptomatic. Despite many decades of intensive research, causal treatment of this common neurologic disorder is still unavailable. Nevertheless, it is expected that advances in modern neuroscience and molecular biology tools, as well as improved animal models may accelerate designing antiepileptogenic and epilepsy-modifying drugs. Epileptogenesis triggers a vast array of genomic, epigenomic and transcriptomic changes, which ultimately lead to morphological and functional transformation of specific neuronal circuits resulting in the occurrence of spontaneous convulsive or nonconvulsive seizures. Recent decades unraveled molecular processes and biochemical signaling pathways involved in the proepileptic transformation of brain circuits including oxidative stress, apoptosis, neuroinflammatory and neurotrophic factors. The "omics" data derived from both human and animal epileptic tissues, as well as electrophysiological, imaging and neurochemical analysis identified a plethora of possible molecular targets for drugs, which could interfere with various stages of epileptogenetic cascade, including inflammatory processes and neuroplastic changes. In this narrative review, we briefly present contemporary views on the neurobiological background of epileptogenesis and discuss the advantages and disadvantages of some more promising molecular targets for antiepileptogenic pharmacotherapy.
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Affiliation(s)
- Katarzyna Łukasiuk
- The Nencki Institute of Experimental Biology, Polish Academy of Sciences, 3 Pasteur St., 02-093 Warsaw, Poland
| | - Władysław Lasoń
- Maj Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343 Kraków, Poland
- Correspondence:
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Ots HD, Anderson T, Sherrerd-Smith W, DelBianco J, Rasic G, Chuprin A, Toor Z, Fitch E, Ahuja K, Reid F, Musto AE. Scoping review of disease-modifying effect of drugs in experimental epilepsy. Front Neurol 2023; 14:1097473. [PMID: 36908628 PMCID: PMC9997527 DOI: 10.3389/fneur.2023.1097473] [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: 11/13/2022] [Accepted: 02/02/2023] [Indexed: 02/25/2023] Open
Abstract
Objective Epilepsy affects ~50 million people worldwide causing significant medical, financial, and sociologic concerns for affected patients and their families. To date, treatment of epilepsy is primarily symptomatic management because few effective preventative or disease-modifying interventions exist. However, recent research has identified neurobiological mechanisms of epileptogenesis, providing new pharmacologic targets to investigate. The current scientific evidence remains scattered across multiple studies using different model and experimental designs. The review compiles different models of anti-epileptogenic investigation and highlights specific compounds with potential epileptogenesis-modifying experimental drugs. It provides a platform for standardization of future epilepsy research to allow a more robust compound analysis of compounds with potential for epilepsy prevention. Methods PubMed, Ovid MEDLINE, and Web of Science were searched from 2007 to 2021. Studies with murine models of epileptogenesis and explicitly detailed experimental procedures were included in the scoping review. In total, 51 articles were selected from 14,983 and then grouped by five core variables: (1) seizure frequency, (2) seizure severity, (3) spontaneous recurrent seizures (SRS), (4) seizure duration, and (5) mossy fiber sprouting (MFS). The variables were differentiated based on experimental models including methods of seizure induction, treatment schedule and timeline of data collection. Data was categorized by the five core variables and analyzed by converting original treatment values to units of percent of its respective control. Results Discrepancies in current epileptogenesis models significantly complicate inter-study comparison of potential anti-epileptogenic interventions. With our analysis, many compounds showed a potential to reduce epileptogenic characteristics defined by the five core variables. WIN55,212-2, aspirin, rapamycin, 1400W, and LEV + BQ788 were identified compounds with the potential of effective anti-epileptic properties. Significance Our review highlights the need for consistent methodology in epilepsy research and provides a novel approach for future research. Inconsistent experimental designs hinder study comparison, slowing the progression of treatments for epilepsy. If the research community can optimize and standardize parameters such as methods of seizure induction, administration schedule, sampling time, and aniMal models, more robust meta-analysis and collaborative research would follow. Additionally, some compounds such as rapamycin, WIN 55,212-2, aspirin, 1400W, and LEV + BQ788 showed anti-epileptogenic modulation across multiple variables. We believe they warrant further study both individually and synergistically.
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Affiliation(s)
- Heather D Ots
- School of Medicine, Eastern Virginia Medical School, Norfolk, VA, United States
| | - Taylor Anderson
- School of Medicine, Eastern Virginia Medical School, Norfolk, VA, United States
| | | | - John DelBianco
- School of Medicine, Eastern Virginia Medical School, Norfolk, VA, United States
| | - Gordana Rasic
- School of Medicine, Eastern Virginia Medical School, Norfolk, VA, United States
| | - Anthony Chuprin
- School of Medicine, Eastern Virginia Medical School, Norfolk, VA, United States
| | - Zeeshan Toor
- School of Medicine, Eastern Virginia Medical School, Norfolk, VA, United States
| | - Elizabeth Fitch
- School of Medicine, Eastern Virginia Medical School, Norfolk, VA, United States
| | - Kripa Ahuja
- School of Medicine, Eastern Virginia Medical School, Norfolk, VA, United States
| | - Faith Reid
- School of Medicine, Eastern Virginia Medical School, Norfolk, VA, United States
| | - Alberto E Musto
- Department of Pathology and Anatomy, Eastern Virginia Medical School, Norfolk, VA, United States.,Department of Neurology, Eastern Virginia Medical School, Norfolk, VA, United States
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Pacheco ALD, de Melo IS, de Araujo Costa M, Amaral MMC, de Gusmão Taveiros Silva NK, Santos YMO, Gitaí DLG, Duzzioni M, Borbely AU, Silva RS, Donatti ALF, Mestriner L, Fuzo CA, Cummings RD, Garcia-Cairasco N, Dias-Baruffi M, de Castro OW. Neuroprotective Effect of Exogenous Galectin-1 in Status Epilepticus. Mol Neurobiol 2022; 59:7354-7369. [PMID: 36171480 DOI: 10.1007/s12035-022-03038-4] [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: 03/30/2022] [Accepted: 09/19/2022] [Indexed: 10/14/2022]
Abstract
Intrahippocampal pilocarpine microinjection (H-PILO) induces status epilepticus (SE) that can lead to spontaneous recurrent seizures (SRS) and neurodegeneration in rodents. Studies using animal models have indicated that lectins mediate a variety of biological activities with neuronal benefits, especially galectin-1 (GAL-1), which has been identified as an effective neuroprotective compound. GAL-1 is associated with the regulation of cell adhesion, proliferation, programmed cell death, and immune responses, as well as attenuating neuroinflammation. Here, we administrated GAL-1 to Wistar rats and evaluated the severity of the SE, neurodegenerative and inflammatory patterns in the hippocampal formation. Administration of GAL-1 caused a reduction in the number of class 2 and 4 seizures, indicating a decrease in seizure severity. Furthermore, we observed a reduction in inflammation and neurodegeneration 24 h and 15 days after SE. Overall, these results suggest that GAL-1 has a neuroprotective effect in the early stage of epileptogenesis and provides new insights into the roles of exogenous lectins in temporal lobe epilepsy (TLE).
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Affiliation(s)
- Amanda Larissa Dias Pacheco
- Institute of Biological Sciences and Health, Federal University of Alagoas (UFAL), Av. Lourival de Melo Mota, km 14, Campus A. C. Simões, Cidade Universitária, Maceió, AL, CEP 57072-970, Brazil
| | - Igor Santana de Melo
- Institute of Biological Sciences and Health, Federal University of Alagoas (UFAL), Av. Lourival de Melo Mota, km 14, Campus A. C. Simões, Cidade Universitária, Maceió, AL, CEP 57072-970, Brazil
| | - Maisa de Araujo Costa
- Institute of Biological Sciences and Health, Federal University of Alagoas (UFAL), Av. Lourival de Melo Mota, km 14, Campus A. C. Simões, Cidade Universitária, Maceió, AL, CEP 57072-970, Brazil
| | - Mariah Morais Celestino Amaral
- Institute of Biological Sciences and Health, Federal University of Alagoas (UFAL), Av. Lourival de Melo Mota, km 14, Campus A. C. Simões, Cidade Universitária, Maceió, AL, CEP 57072-970, Brazil
| | - Nívea Karla de Gusmão Taveiros Silva
- Institute of Biological Sciences and Health, Federal University of Alagoas (UFAL), Av. Lourival de Melo Mota, km 14, Campus A. C. Simões, Cidade Universitária, Maceió, AL, CEP 57072-970, Brazil
| | - Yngrid Mickaelli Oliveira Santos
- Institute of Biological Sciences and Health, Federal University of Alagoas (UFAL), Av. Lourival de Melo Mota, km 14, Campus A. C. Simões, Cidade Universitária, Maceió, AL, CEP 57072-970, Brazil
| | - Daniel Leite Góes Gitaí
- Institute of Biological Sciences and Health, Federal University of Alagoas (UFAL), Av. Lourival de Melo Mota, km 14, Campus A. C. Simões, Cidade Universitária, Maceió, AL, CEP 57072-970, Brazil
| | - Marcelo Duzzioni
- Institute of Biological Sciences and Health, Federal University of Alagoas (UFAL), Av. Lourival de Melo Mota, km 14, Campus A. C. Simões, Cidade Universitária, Maceió, AL, CEP 57072-970, Brazil
| | - Alexandre Urban Borbely
- Institute of Biological Sciences and Health, Federal University of Alagoas (UFAL), Av. Lourival de Melo Mota, km 14, Campus A. C. Simões, Cidade Universitária, Maceió, AL, CEP 57072-970, Brazil
| | - Robinson Sabino Silva
- Department of Physiology, Institute of Biomedical Sciences, Federal University of Uberlândia (UFU), Uberlândia, MG, Brazil
| | - Ana Luiza Ferreira Donatti
- Department of Physiology, Medical School of Ribeirão Preto, University of São Paulo (USP), Ribeirão Preto, São Paulo, Brazil.,Department of Neuroscience and Behavioral Sciences, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Luisa Mestriner
- Department of Clinical Analyses, Toxicology, and Food Sciences, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo (USP), Ribeirão Preto, São Paulo, Brazil
| | - Carlos Alessandro Fuzo
- Department of Clinical Analyses, Toxicology, and Food Sciences, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo (USP), Ribeirão Preto, São Paulo, Brazil
| | - Richard D Cummings
- Beth Israel Deaconess Medical Center, Department of Surgery, Harvard Glycomics Center, Harvard Medical School, CLS 11087 - 3 Blackfan Circle, Boston, MA, 02115, USA
| | - Norberto Garcia-Cairasco
- Department of Physiology, Medical School of Ribeirão Preto, University of São Paulo (USP), Ribeirão Preto, São Paulo, Brazil.,Department of Neuroscience and Behavioral Sciences, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Marcelo Dias-Baruffi
- Department of Clinical Analyses, Toxicology, and Food Sciences, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo (USP), Ribeirão Preto, São Paulo, Brazil.
| | - Olagide Wagner de Castro
- Institute of Biological Sciences and Health, Federal University of Alagoas (UFAL), Av. Lourival de Melo Mota, km 14, Campus A. C. Simões, Cidade Universitária, Maceió, AL, CEP 57072-970, Brazil.
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9
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A review on role of metformin as a potential drug for epilepsy treatment and modulation of epileptogenesis. Seizure 2022; 101:253-261. [PMID: 36116284 DOI: 10.1016/j.seizure.2022.09.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2022] [Revised: 09/01/2022] [Accepted: 09/03/2022] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Available anti-seizure medications (ASMs) target the symptomatology of the disease rather than any significant disease/epileptogenesis modifying actions. There are critical concerns of drug resistance and seizure recurrence during epilepsy management. So, drug repurposing is evolving as a paradigm change in the quest for novel epilepsy treatment strategies. Metformin, a well-known anti-diabetic drug has shown multiple pieces of evidence of its potential antiepileptic action. OBJECTIVE This review elucidates various mechanisms underlying the beneficial role of metformin in seizure control and modulation of the epileptogenesis process. METHODS Preclinical and clinical evidence involving metformin's role in epilepsy and special conditions like tuberous sclerosis have been reviewed in this paper. The putative mechanisms of epileptogenesis modulation through the use of metformin are also summarised. RESULTS This review found the efficacy of metformin in different seizure models including genetic knockout model, chemical induced, and kindling models. Only one clinical study of metformin in tuberous sclerosis has shown a reduction in seizure frequency and tumor volume compared to placebo. The suggested mechanisms of metformin relevant to epileptogenesis modulation mainly encompass AMPK activation, mTOR inhibition, protection against blood-brain-barrier disruption, inhibition of neuronal apoptosis, and reduction of oxidative stress. In addition to seizure protection, metformin has a potential role in attenuating adverse effects associated with epilepsy and ASMs such as cognition and memory impairment. CONCLUSION Metformin has shown promising utility in epilepsy management and epileptogenesis modulation. The evidence in this review substantiates the need for a robust clinical trial to explore the efficacy and safety of metformin in persons with epilepsy.
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10
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mTOR and HDAC2 are simultaneously activated during electrically induced kindling of seizures. Epilepsy Res 2022; 185:106991. [DOI: 10.1016/j.eplepsyres.2022.106991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 07/27/2022] [Accepted: 07/28/2022] [Indexed: 11/23/2022]
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11
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Adenosine A 2A receptors control synaptic remodeling in the adult brain. Sci Rep 2022; 12:14690. [PMID: 36038626 PMCID: PMC9424208 DOI: 10.1038/s41598-022-18884-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 08/22/2022] [Indexed: 01/04/2023] Open
Abstract
The molecular mechanisms underlying circuit re-wiring in the mature brain remains ill-defined. An eloquent example of adult circuit remodelling is the hippocampal mossy fiber (MF) sprouting found in diseases such as temporal lobe epilepsy. The molecular determinants underlying this retrograde re-wiring remain unclear. This may involve signaling system(s) controlling axon specification/growth during neurodevelopment reactivated during epileptogenesis. Since adenosine A2A receptors (A2AR) control axon formation/outgrowth and synapse stabilization during development, we now examined the contribution of A2AR to MF sprouting. A2AR blockade significantly attenuated status epilepticus(SE)-induced MF sprouting in a rat pilocarpine model. This involves A2AR located in dentate granule cells since their knockdown selectively in dentate granule cells reduced MF sprouting, most likely through the ability of A2AR to induce the formation/outgrowth of abnormal secondary axons found in rat hippocampal neurons. These A2AR should be activated by extracellular ATP-derived adenosine since a similar prevention/attenuation of SE-induced hippocampal MF sprouting was observed in CD73 knockout mice. These findings demonstrate that A2AR contribute to epilepsy-related MF sprouting, most likely through the reactivation of the ability of A2AR to control axon formation/outgrowth observed during neurodevelopment. These results frame the CD73-A2AR axis as a regulator of circuit remodeling in the mature brain.
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12
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Molecular Mechanism and Regulation of Autophagy and Its Potential Role in Epilepsy. Cells 2022; 11:cells11172621. [PMID: 36078029 PMCID: PMC9455075 DOI: 10.3390/cells11172621] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 08/14/2022] [Accepted: 08/22/2022] [Indexed: 01/18/2023] Open
Abstract
Autophagy is an evolutionally conserved degradation mechanism for maintaining cell homeostasis whereby cytoplasmic components are wrapped in autophagosomes and subsequently delivered to lysosomes for degradation. This process requires the concerted actions of multiple autophagy-related proteins and accessory regulators. In neurons, autophagy is dynamically regulated in different compartments including soma, axons, and dendrites. It determines the turnover of selected materials in a spatiotemporal control manner, which facilitates the formation of specialized neuronal functions. It is not surprising, therefore, that dysfunctional autophagy occurs in epilepsy, mainly caused by an imbalance between excitation and inhibition in the brain. In recent years, much attention has been focused on how autophagy may cause the development of epilepsy. In this article, we overview the historical landmarks and distinct types of autophagy, recent progress in the core machinery and regulation of autophagy, and biological roles of autophagy in homeostatic maintenance of neuronal structures and functions, with a particular focus on synaptic plasticity. We also discuss the relevance of autophagy mechanisms to the pathophysiology of epileptogenesis.
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13
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Wu X, Sosunov AA, Lado W, Teoh JJ, Ham A, Li H, Al-Dalahmah O, Gill BJA, Arancio O, Schevon CA, Frankel WN, McKhann GM, Sulzer D, Goldman JE, Tang G. Synaptic hyperexcitability of cytomegalic pyramidal neurons contributes to epileptogenesis in tuberous sclerosis complex. Cell Rep 2022; 40:111085. [PMID: 35858542 PMCID: PMC9376014 DOI: 10.1016/j.celrep.2022.111085] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 02/15/2022] [Accepted: 06/22/2022] [Indexed: 11/27/2022] Open
Abstract
Tuberous sclerosis complex (TSC) is a developmental disorder associated with epilepsy, autism, and cognitive impairment. Despite inactivating mutations in the TSC1 or TSC2 genes and hyperactive mechanistic target of rapamycin (mTOR) signaling, the mechanisms underlying TSC-associated neurological symptoms remain incompletely understood. Here we generate a Tsc1 conditional knockout (CKO) mouse model in which Tsc1 inactivation in late embryonic radial glia causes social and cognitive impairment and spontaneous seizures. Tsc1 depletion occurs in a subset of layer 2/3 cortical pyramidal neurons, leading to development of cytomegalic pyramidal neurons (CPNs) that mimic dysplastic neurons in human TSC, featuring abnormal dendritic and axonal overgrowth, enhanced glutamatergic synaptic transmission, and increased susceptibility to seizure-like activities. We provide evidence that enhanced synaptic excitation in CPNs contributes to cortical hyperexcitability and epileptogenesis. In contrast, astrocytic regulation of synapse formation and synaptic transmission remains unchanged after late embryonic radial glial Tsc1 inactivation, and astrogliosis evolves secondary to seizures. Wu et al. demonstrate that Tsc1 inactivation in late embryonic radial glial cells (RGCs) produces cytomegalic pyramidal neurons that mimic TSC-like dysplastic neurons. They find that enhanced excitatory synaptic transmission in Tsc1-null cytomegalic pyramidal neurons contributes to cortical hyperexcitability and epileptogenesis.
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Affiliation(s)
- Xiaoping Wu
- Department of Neurological Surgery, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Alexander A Sosunov
- Department of Neurological Surgery, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Wudu Lado
- Department of Neurology, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Jia Jie Teoh
- Institute for Genomic Medicine, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Ahrom Ham
- Department of Neurology, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Hongyu Li
- Department of Neurology, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Osama Al-Dalahmah
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Brian J A Gill
- Department of Neurological Surgery, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Ottavio Arancio
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY 10032, USA; Department of Medicine, Columbia University Irving Medical Center, New York, NY 10032, USA; The Taub Institute, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Catherine A Schevon
- Department of Neurology, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Wayne N Frankel
- Institute for Genomic Medicine, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Guy M McKhann
- Department of Neurological Surgery, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - David Sulzer
- Department of Psychiatry, Columbia University Irving Medical Center, New York, NY 10032, USA; Department of Pharmacology, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - James E Goldman
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY 10032, USA; The Taub Institute, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Guomei Tang
- Department of Neurology, Columbia University Irving Medical Center, New York, NY 10032, USA.
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14
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Salaka RJ, Nair KP, Sasibhushana RB, Udayakumar D, Kutty BM, Srikumar BN, Shankaranarayana Rao BS. Differential effects of levetiracetam on hippocampal CA1 synaptic plasticity and molecular changes in the dentate gyrus in epileptic rats. Neurochem Int 2022; 158:105378. [PMID: 35753511 DOI: 10.1016/j.neuint.2022.105378] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 05/27/2022] [Accepted: 06/12/2022] [Indexed: 11/25/2022]
Abstract
Temporal lobe epilepsy (TLE) is the most common form of focal epilepsies. Pharmacological treatment with anti-seizure drugs (ASDs) remains the mainstay in epilepsy management. Levetiracetam (LEV) is a second-generation ASD with a novel SV2A protein target and is indicated for treating focal epilepsies. While there is considerable literature in acute models, its effect in chronic epilepsy is less clear. Particularly, its effects on neuronal excitability, synaptic plasticity, adult hippocampal neurogenesis, and histological changes in chronic epilepsy have not been evaluated thus far, which formed the basis of the present study. Six weeks post-lithium-pilocarpine-induced status epilepticus (SE), epileptic rats were injected with levetiracetam (54mg/kg b.w. i.p.) once daily for two weeks. Following LEV treatment, Schaffer collateral - CA1 (CA3-CA1) synaptic plasticity and structural changes in hippocampal subregions CA3 and CA1 were evaluated. The number of doublecortin (DCX+) and reelin (RLN+) positive neurons was estimated. Further, mossy fiber sprouting was evaluated in DG by Timm staining, and splash test was performed to assess the anxiety-like behavior. Chronic epilepsy resulted in decreased basal synaptic transmission and increased paired-pulse facilitation without affecting post-tetanic potentiation and long-term potentiation. Moreover, chronic epilepsy decreased hippocampal subfields volume, adult hippocampal neurogenesis, and increased reelin expression and mossy fiber sprouting with increased anxiety-like behavior. LEV treatment restored basal synaptic transmission and paired-pulse facilitation ratio in CA3-CA1 synapses. LEV also restored the CA1 subfield volume in chronic epilepsy. LEV did not affect epilepsy-induced abnormal adult hippocampal neurogenesis, ectopic migration of newborn granule cells, mossy fiber sprouting in DG, and anxiety-like behavior. Our results indicate that in addition to reducing seizures, LEV has favorable effects on synaptic transmission and structural plasticity in chronic epilepsy. These findings add new dimensions to the use of LEV in chronic epilepsy and paves way for further research into its effects on cognition and affective behavior.
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Affiliation(s)
- Raghava Jagadeesh Salaka
- Department of Neurophysiology, National Institute of Mental Health and Neuro Sciences, Bengaluru, India
| | - Kala P Nair
- Department of Neurophysiology, National Institute of Mental Health and Neuro Sciences, Bengaluru, India
| | | | - Deepashree Udayakumar
- Department of Neurophysiology, National Institute of Mental Health and Neuro Sciences, Bengaluru, India
| | - Bindu M Kutty
- Department of Neurophysiology, National Institute of Mental Health and Neuro Sciences, Bengaluru, India
| | - Bettadapura N Srikumar
- Department of Neurophysiology, National Institute of Mental Health and Neuro Sciences, Bengaluru, India
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15
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Seelman A, Vu K, Buckmaster P, Mackie K, Field C, Johnson S, Wyeth M. Cannabinoid receptor 1-labeled boutons in the sclerotic dentate gyrus of epileptic sea lions. Epilepsy Res 2022; 184:106965. [PMID: 35724601 DOI: 10.1016/j.eplepsyres.2022.106965] [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: 12/27/2021] [Revised: 05/13/2022] [Accepted: 06/10/2022] [Indexed: 11/03/2022]
Abstract
Pathology in the dentate gyrus, including sclerosis, is a hallmark of temporal lobe epilepsy, and reduced inhibition to dentate granule cells may contribute to epileptogenesis. The perisomatic-targeting axonal boutons of parvalbumin-expressing interneurons decrease in proportion with granule cells in temporal lobe epilepsy. In contrast, dendrite-targeting axonal boutons of somatostatin-expressing interneurons sprout exuberantly in temporal lobe epilepsy. A third major class of GABAergic interneurons expresses cannabinoid receptor type 1 (CB1) on their terminal boutons, but there is conflicting evidence as to whether these boutons are increased or decreased in temporal lobe epilepsy. Naturally occurring temporal lobe epilepsy in California sea lions, with unilateral or bilateral sclerosis, offers the benefit of neuroanatomy and neuropathology akin to humans, but with the advantage that the entirety of both hippocampi from control and epileptic brains can be studied. Stereological quantification in the dentate gyrus revealed that sclerotic hippocampi from epileptic sea lions had fewer CB1-labeled boutons than controls. However, the reduction in the number of granule cells was greater, resulting in increased CB1-labeled boutons per granule cell in sclerotic hippocampi at temporal levels. This suggests that although CB1-expressing boutons are decreased in sclerotic dentate gyri, surviving cells have enhanced innervation from these boutons in epileptic sea lions.
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Affiliation(s)
- Amanda Seelman
- Department of Comparative Medicine, School of Medicine, Stanford University, 300 Pasteur Drive, Stanford, CA 94305, USA; College of Veterinary Medicine, Western University of Health Sciences, East 2nd Street, Pomona, CA 91766, USA
| | - Kristina Vu
- Department of Comparative Medicine, School of Medicine, Stanford University, 300 Pasteur Drive, Stanford, CA 94305, USA; College of Veterinary Medicine, Cornell University, 602 Tower Rd, Ithaca, NY 14853, USA
| | - Paul Buckmaster
- Department of Comparative Medicine, School of Medicine, Stanford University, 300 Pasteur Drive, Stanford, CA 94305, USA
| | - Ken Mackie
- Department of Psychological & Brain Sciences, Indiana University, 1101 E 10th Street, Bloomington, IN 47405, USA; Gill Centre for Biomolecular Science, Indiana University, 702 North Walnut Grove Avenue, Bloomington, IN 47405, USA
| | - Cara Field
- The Marine Mammal Center, 2000 Bunker Road, Sausalito, CA 94965, USA
| | - Shawn Johnson
- The Marine Mammal Center, 2000 Bunker Road, Sausalito, CA 94965, USA
| | - Megan Wyeth
- Department of Comparative Medicine, School of Medicine, Stanford University, 300 Pasteur Drive, Stanford, CA 94305, USA.
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16
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Drion CM, Kooijman L, Chan D, Berkhout J, van Vliet EA, Wadman WJ, Gorter JA. No persistent effects of intracerebral curcumin administration on seizure progression and neuropathology in the kindling rat model for temporal lobe epilepsy. Epilepsy Res 2022; 181:106873. [DOI: 10.1016/j.eplepsyres.2022.106873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 01/19/2022] [Accepted: 02/03/2022] [Indexed: 11/03/2022]
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17
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Sun L, Liu R, Yang H, Yu T, Wu J, Wang Q. Characteristics of Epileptiform Spike-wave Discharges and Chronic Histopathology in Controlled Cortical Impact Model of Sprague-Dawley Rats. Neurochem Res 2022; 47:3615-3626. [PMID: 35103912 DOI: 10.1007/s11064-022-03542-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Revised: 01/17/2022] [Accepted: 01/24/2022] [Indexed: 10/19/2022]
Abstract
Post-traumatic epilepsy (PTE) is a serious complication that can occur following traumatic brain injury (TBI). Sustained secondary changes after TBI promote the process of PTE. Here, we aim to evaluate changes in behavior, electrocorticogram, and histomorphology in rats following chronic TBI models. We observed intensive 7-8 Hz spike-wave-discharges (SWDs) at frontal recording sites and quantified them in SD rats with different degrees of TBI and compared them with age-matched sham rats to evaluate the association between SWDs and injury severity. Notably, although SWDs were even presented in the sham group, the number and duration of events were much lower than those in the TBI groups. SWDs have numerous similarities to absence seizures, such as abrupt onset, termination, and lack of postictal suppression, which may be the nonconvulsive characteristics of PTE. Retigabine, a novel antiepileptic drug, is ineffective in reducing SWDs. In addition, we examined chronic histopathological changes in TBI rats. Rats subjected to moderate and severe TBI exhibited significantly impaired neurological function, which was accompanied by marked cortical injury, hippocampus deformation, reactive gliosis, and mossy fiber sprouting. Long-term progressive structural changes in the brain are one of the characteristics of epileptogenesis after TBI. Our study provided the potential value of epileptiform SWDs in reflecting the nonconvulsive characteristic of PTE and highlighted the vital role of chronic pathological changes, such as reactive gliosis, in promoting the epileptogenesis following TBI.
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Affiliation(s)
- Lei Sun
- Beijing Tiantan Hospital, Capital Medical University, Beijing, 100070, China.,Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing, 100070, China.,China National Clinical Research Center for Neurological Diseases, Beijing, 100070, China
| | - Ru Liu
- Beijing Tiantan Hospital, Capital Medical University, Beijing, 100070, China.,Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing, 100070, China.,China National Clinical Research Center for Neurological Diseases, Beijing, 100070, China
| | - Huajun Yang
- Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing, 100070, China.,Beijing Friendship Hospital, Capital Medical University, Beijing, 100050, China
| | - Tingting Yu
- Beijing Tiantan Hospital, Capital Medical University, Beijing, 100070, China.,Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing, 100070, China.,China National Clinical Research Center for Neurological Diseases, Beijing, 100070, China
| | - Jianping Wu
- Beijing Tiantan Hospital, Capital Medical University, Beijing, 100070, China. .,Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing, 100070, China. .,China National Clinical Research Center for Neurological Diseases, Beijing, 100070, China. .,School of Chemistry, Chemical Engineering and Life Sciences, Wuhan University of Technology, Wuhan, 430070, China.
| | - Qun Wang
- Beijing Tiantan Hospital, Capital Medical University, Beijing, 100070, China. .,China National Clinical Research Center for Neurological Diseases, Beijing, 100070, China. .,Beijing Institute for Brain Disorders, Beijing, 100069, China.
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18
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Fernandez AM, Gutekunst CA, Grogan DP, Pedersen NP, Gross RE. Loss of efferent projections of the hippocampal formation in the mouse intrahippocampal kainic acid model. Epilepsy Res 2022; 180:106863. [PMID: 35114430 DOI: 10.1016/j.eplepsyres.2022.106863] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 12/15/2021] [Accepted: 01/17/2022] [Indexed: 11/16/2022]
Abstract
Unilateral intrahippocampal injection of kainic acid is used as a model of medial temporal lobe epilepsy and provides a platform to study the mechanisms of epilepsy. Here, we used an AAV-9 EYFP-tagged viral vector as an anterograde tracer, injected into the dorsal and ventral hippocampus after kainic acid injection, to map out the efferent hippocampal projections after the development of spontaneous seizures in this model. The purpose of the study was to identify the extent of changes in hippocampal efferent system in several brain regions that receive significant inputs from the hippocampus. Loss of efferent hippocampal fibers was greatest in the retrosplenial cortex where neuronal loss was also observed. Loss of fibers was also observed in the fornix without any specific effect in the lateral mammillary nuclei. Although expected, these observations provide further evidence of the broader network effects as a result of hippocampal cell loss.
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Affiliation(s)
- Alejandra M Fernandez
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Claire-Anne Gutekunst
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, GA, 30322, USA.
| | - Dayton P Grogan
- Department of Neurosurgery, Augusta University Hospital, Augusta, GA, 30912, USA
| | - Nigel P Pedersen
- Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, 30332, USA; Department of Neurology, Emory University, Atlanta, GA, 30322, USA
| | - Robert E Gross
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, GA, 30322, USA; Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, 30332, USA; Department of Neurology, Emory University, Atlanta, GA, 30322, USA.
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19
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Ma KG, Hu HB, Zhou JS, Ji C, Yan QS, Peng SM, Ren LD, Yang BN, Xiao XL, Ma YB, Wu F, Si KW, Wu XL, Liu JX. Neuronal Glypican4 promotes mossy fiber sprouting through the mTOR pathway after pilocarpine-induced status epilepticus in mice. Exp Neurol 2021; 347:113918. [PMID: 34748756 DOI: 10.1016/j.expneurol.2021.113918] [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: 05/11/2021] [Revised: 10/27/2021] [Accepted: 11/02/2021] [Indexed: 02/07/2023]
Abstract
In temporal lobe epilepsy (TLE), abnormal axon guidance and synapse formation lead to sprouting of mossy fibers in the hippocampus, which is one of the most consistent pathological findings in patients and animal models with TLE. Glypican 4 (Gpc4) belongs to the heparan sulfate proteoglycan family, which play an important role in axon guidance and excitatory synapse formation. However, the role of Gpc4 in the development of mossy fibers sprouting (MFS) and its underlying mechanism remain unknown. Using a pilocarpine-induced mice model of epilepsy, we showed that Gpc4 expression was significantly increased in the stratum granulosum of the dentate gyrus at 1 week after status epilepticus (SE). Using Gpc4 overexpression or Gpc4 shRNA lentivirus to regulate the Gpc4 level in the dentate gyrus, increased or decreased levels of netrin-1, SynI, PSD-95, and Timm score were observed in the dentate gyrus, indicating a crucial role of Gpc4 in modulating the development of functional MFS. The observed effects of Gpc4 on MFS were significantly antagonized when mice were treated with L-leucine or rapamycin, an agonist or antagonist of the mammalian target of rapamycin (mTOR) signal, respectively, demonstrating that mTOR pathway is an essential requirement for Gpc4-regulated MFS. Additionally, the attenuated spontaneous recurrent seizures (SRSs) were observed during chronic stage of the disease by suppressing the Gpc4 expression after SE. Altogether, our findings demonstrate a novel control of neuronal Gpc4 on the development of MFS through the mTOR pathway after pilocarpine-induced SE. Our results also strongly suggest that Gpc4 may serve as a promising target for antiepileptic studies.
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Affiliation(s)
- Kai-Ge Ma
- Institute of Neurobiology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, Xi'an 710061, China
| | - Hai-Bo Hu
- Department of Human Anatomy, Histology and Embryology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, Xi'an 710061, China
| | - Jin-Song Zhou
- Department of Human Anatomy, Histology and Embryology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, Xi'an 710061, China
| | - Chao Ji
- Qide College, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, Xi'an 710061, China
| | - Qi-Sheng Yan
- Qide College, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, Xi'an 710061, China
| | - Si-Ming Peng
- Zonglian College, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, Xi'an 710061, China
| | - Lan-Dong Ren
- Zonglian College, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, Xi'an 710061, China
| | - Bing-Nan Yang
- Institute of Neuroscience, Translational Medicine Institute, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, Xi'an 710061, China
| | - Xin-Li Xiao
- Department of Human Anatomy, Histology and Embryology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, Xi'an 710061, China; Institute of Neuroscience, Translational Medicine Institute, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, Xi'an 710061, China
| | - Yan-Bing Ma
- Department of Human Anatomy, Histology and Embryology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, Xi'an 710061, China
| | - Feng Wu
- Center of Teaching and Experiment for Medical Post Graduates, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, Xi'an 710061, China
| | - Kai-Wei Si
- Department of Pathogenic Biology and Immunology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, Xi'an 710061, China
| | - Xiao-Lin Wu
- Department of Human Anatomy, Histology and Embryology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, Xi'an 710061, China; Institute of Neuroscience, Translational Medicine Institute, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, Xi'an 710061, China.
| | - Jian-Xin Liu
- Institute of Neurobiology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, Xi'an 710061, China; Institute of Neuroscience, Translational Medicine Institute, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, Xi'an 710061, China.
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20
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Twible C, Abdo R, Zhang Q. Astrocyte Role in Temporal Lobe Epilepsy and Development of Mossy Fiber Sprouting. Front Cell Neurosci 2021; 15:725693. [PMID: 34658792 PMCID: PMC8514632 DOI: 10.3389/fncel.2021.725693] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 09/02/2021] [Indexed: 11/13/2022] Open
Abstract
Epilepsy affects approximately 50 million people worldwide, with 60% of adult epilepsies presenting an onset of focal origin. The most common focal epilepsy is temporal lobe epilepsy (TLE). The role of astrocytes in the presentation and development of TLE has been increasingly studied and discussed within the literature. The most common histopathological diagnosis of TLE is hippocampal sclerosis. Hippocampal sclerosis is characterized by neuronal cell loss within the Cornu ammonis and reactive astrogliosis. In some cases, mossy fiber sprouting may be observed. Mossy fiber sprouting has been controversial in its contribution to epileptogenesis in TLE patients, and the mechanisms surrounding the phenomenon have yet to be elucidated. Several studies have reported that mossy fiber sprouting has an almost certain co-existence with reactive astrogliosis within the hippocampus under epileptic conditions. Astrocytes are known to play an important role in the survival and axonal outgrowth of central and peripheral nervous system neurons, pointing to a potential role of astrocytes in TLE and associated cellular alterations. Herein, we review the recent developments surrounding the role of astrocytes in the pathogenic process of TLE and mossy fiber sprouting, with a focus on proposed signaling pathways and cellular mechanisms, histological observations, and clinical correlations in human patients.
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Affiliation(s)
- Carolyn Twible
- Department of Pathology and Lab Medicine, Western University, London, ON, Canada
| | - Rober Abdo
- Department of Pathology and Lab Medicine, Western University, London, ON, Canada.,Department of Anatomy and Cell Biology, Western University, London, ON, Canada
| | - Qi Zhang
- Department of Pathology and Lab Medicine, Western University, London, ON, Canada.,Department of Pathology and Lab Medicine, London Health Sciences Centre, University Hospital, London, ON, Canada
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21
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Selected Molecular Targets for Antiepileptogenesis. Int J Mol Sci 2021; 22:ijms22189737. [PMID: 34575901 PMCID: PMC8466306 DOI: 10.3390/ijms22189737] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 09/02/2021] [Accepted: 09/02/2021] [Indexed: 02/07/2023] Open
Abstract
The term epileptogenesis defines the usually durable process of converting normal brain into an epileptic one. The resistance of a significant proportion of patients with epilepsy to the available pharmacotherapy prompted the concept of a causative treatment option consisting in stopping or modifying the progress of epileptogenesis. Most antiepileptic drugs possess only a weak or no antiepileptogenic potential at all, but a few of them appear promising in this regard; these include, for example, eslicarbazepine (a sodium and T-type channel blocker), lamotrigine (a sodium channel blocker and glutamate antagonist) or levetiracetam (a ligand of synaptic vehicle protein SV2A). Among the approved non-antiepileptic drugs, antiepileptogenic potential seems to reside in losartan (a blocker of angiotensin II type 1 receptors), biperiden (an antiparkinsonian drug), nonsteroidal anti-inflammatory drugs, antioxidative drugs and minocycline (a second-generation tetracycline with anti-inflammatory and antioxidant properties). Among other possible antiepileptogenic compounds, antisense nucleotides have been considered, among these an antagomir targeting microRNA-134. The drugs and agents mentioned above have been evaluated in post-status epilepticus models of epileptogenesis, so their preventive efficacy must be verified. Limited clinical data indicate that biperiden in patients with brain injuries is well-tolerated and seems to reduce the incidence of post-traumatic epilepsy. Exceptionally, in this regard, our own original data presented here point to c-Fos as an early seizure duration, but not seizure intensity-related, marker of early epileptogenesis. Further research of reliable markers of early epileptogenesis is definitely needed to improve the process of designing adequate antiepileptogenic therapies.
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A Warburg-like metabolic program coordinates Wnt, AMPK, and mTOR signaling pathways in epileptogenesis. PLoS One 2021; 16:e0252282. [PMID: 34358226 PMCID: PMC8345866 DOI: 10.1371/journal.pone.0252282] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 05/12/2021] [Indexed: 02/06/2023] Open
Abstract
Epilepsy is a complex neurological condition characterized by repeated spontaneous seizures and can be induced by initiating seizures known as status epilepticus (SE). Elaborating the critical molecular mechanisms following SE are central to understanding the establishment of chronic seizures. Here, we identify a transient program of molecular and metabolic signaling in the early epileptogenic period, centered on day five following SE in the pre-clinical kainate or pilocarpine models of temporal lobe epilepsy. Our work now elaborates a new molecular mechanism centered around Wnt signaling and a growing network comprised of metabolic reprogramming and mTOR activation. Biochemical, metabolomic, confocal microscopy and mouse genetics experiments all demonstrate coordinated activation of Wnt signaling, predominantly in neurons, and the ensuing induction of an overall aerobic glycolysis (Warburg-like phenomenon) and an altered TCA cycle in early epileptogenesis. A centerpiece of the mechanism is the regulation of pyruvate dehydrogenase (PDH) through its kinase and Wnt target genes PDK4. Intriguingly, PDH is a central gene in certain genetic epilepsies, underscoring the relevance of our elaborated mechanisms. While sharing some features with cancers, the Warburg-like metabolism in early epileptogenesis is uniquely split between neurons and astrocytes to achieve an overall novel metabolic reprogramming. This split Warburg metabolic reprogramming triggers an inhibition of AMPK and subsequent activation of mTOR, which is a signature event of epileptogenesis. Interrogation of the mechanism with the metabolic inhibitor 2-deoxyglucose surprisingly demonstrated that Wnt signaling and the resulting metabolic reprogramming lies upstream of mTOR activation in epileptogenesis. To augment the pre-clinical pilocarpine and kainate models, aspects of the proposed mechanisms were also investigated and correlated in a genetic model of constitutive Wnt signaling (deletion of the transcriptional repressor and Wnt pathway inhibitor HBP1). The results from the HBP1-/- mice provide a genetic evidence that Wnt signaling may set the threshold of acquired seizure susceptibility with a similar molecular framework. Using biochemistry and genetics, this paper outlines a new molecular framework of early epileptogenesis and advances a potential molecular platform for refining therapeutic strategies in attenuating recurrent seizures.
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Scopolamine prevents aberrant mossy fiber sprouting and facilitates remission of epilepsy after brain injury. Neurobiol Dis 2021; 158:105446. [PMID: 34280524 DOI: 10.1016/j.nbd.2021.105446] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 07/01/2021] [Accepted: 07/13/2021] [Indexed: 11/21/2022] Open
Abstract
Prevention or modification of acquired epilepsy in patients at risk is an urgent, yet unmet, clinical need. Following acute brain insults, there is an increased risk of mesial temporal lobe epilepsy (mTLE), which is often associated with debilitating comorbidities and reduced life expectancy. The latent period between brain injury and the onset of epilepsy may offer a therapeutic window for interfering with epileptogenesis. The pilocarpine model of mTLE is widely used in the search for novel antiepileptogenic treatments. Recent biochemical studies indicated that cholinergic mechanisms play a role in the epileptogenic alterations induced by status epilepticus (SE) in this and other models of mTLE, which prompted us to evaluate whether treatment with the muscarinic antagonist scopolamine during the latent period after SE is capable of preventing or modifying epilepsy and associated behavioral and cognitive alterations in female Sprague-Dawley rats. First, in silico pharmacokinetic modeling was used to select a dosing protocol by which M-receptor inhibitory brain levels of scopolamine are maintained during prolonged treatment. This protocol was verified by drug analysis in vivo. Rats were then treated twice daily with scopolamine over 17 days after SE, followed by drug wash-out and behavioral and video/EEG monitoring up to ~6 months after SE. Compared to vehicle controls, rats that were treated with scopolamine during the latent period exhibited a significantly lower incidence of spontaneous recurrent seizures during periods of intermittent recording in the chronic phase of epilepsy, less behavioral excitability, less cognitive impairment, and significantly reduced aberrant mossy fiber sprouting in the hippocampus. The present data may indicate that scopolamine exerts antiepileptogenic/disease-modifying activity in the lithium-pilocarpine rat model, possibly involving increased remission of epilepsy as a new mechanism of disease-modification. For evaluating the rigor of the present data, we envision a study that more thoroughly addresses the gender bias and video-EEG recording limitations of the present study.
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Littlejohn EL, DeSana AJ, Williams HC, Chapman RT, Joseph B, Juras JA, Saatman KE. IGF1-Stimulated Posttraumatic Hippocampal Remodeling Is Not Dependent on mTOR. Front Cell Dev Biol 2021; 9:663456. [PMID: 34095131 PMCID: PMC8174097 DOI: 10.3389/fcell.2021.663456] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 04/26/2021] [Indexed: 01/29/2023] Open
Abstract
Adult hippocampal neurogenesis is stimulated acutely following traumatic brain injury (TBI). However, many hippocampal neurons born after injury develop abnormally and the number that survive long-term is debated. In experimental TBI, insulin-like growth factor-1 (IGF1) promotes hippocampal neuronal differentiation, improves immature neuron dendritic arbor morphology, increases long-term survival of neurons born after TBI, and improves cognitive function. One potential downstream mediator of the neurogenic effects of IGF1 is mammalian target of rapamycin (mTOR), which regulates proliferation as well as axonal and dendritic growth in the CNS. Excessive mTOR activation is posited to contribute to aberrant plasticity related to posttraumatic epilepsy, spurring preclinical studies of mTOR inhibitors as therapeutics for TBI. The degree to which pro-neurogenic effects of IGF1 depend upon upregulation of mTOR activity is currently unknown. Using immunostaining for phosphorylated ribosomal protein S6, a commonly used surrogate for mTOR activation, we show that controlled cortical impact TBI triggers mTOR activation in the dentate gyrus in a time-, region-, and injury severity-dependent manner. Posttraumatic mTOR activation in the granule cell layer (GCL) and dentate hilus was amplified in mice with conditional overexpression of IGF1. In contrast, delayed astrocytic activation of mTOR signaling within the dentate gyrus molecular layer, closely associated with proliferation, was not affected by IGF1 overexpression. To determine whether mTOR activation is necessary for IGF1-mediated stimulation of posttraumatic hippocampal neurogenesis, wildtype and IGF1 transgenic mice received the mTOR inhibitor rapamycin daily beginning at 3 days after TBI, following pulse labeling with bromodeoxyuridine. Compared to wildtype mice, IGF1 overexpressing mice exhibited increased posttraumatic neurogenesis, with a higher density of posttrauma-born GCL neurons at 10 days after injury. Inhibition of mTOR did not abrogate IGF1-stimulated enhancement of posttraumatic neurogenesis. Rather, rapamycin treatment in IGF1 transgenic mice, but not in WT mice, increased numbers of cells labeled with BrdU at 3 days after injury that survived to 10 days, and enhanced the proportion of posttrauma-born cells that differentiated into neurons. Because beneficial effects of IGF1 on hippocampal neurogenesis were maintained or even enhanced with delayed inhibition of mTOR, combination therapy approaches may hold promise for TBI.
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Affiliation(s)
| | | | | | | | | | | | - Kathryn E. Saatman
- Department of Physiology, Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY, United States
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Basu T, Maguire J, Salpekar JA. Hypothalamic-pituitary-adrenal axis targets for the treatment of epilepsy. Neurosci Lett 2021; 746:135618. [PMID: 33429002 DOI: 10.1016/j.neulet.2020.135618] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 12/25/2020] [Accepted: 12/29/2020] [Indexed: 12/20/2022]
Abstract
Stress is a common seizure trigger in persons with epilepsy. The body's physiological response to stress is mediated by the hypothalamic-pituitary-adrenal (HPA) axis and involves a hormonal cascade that includes corticotropin releasing hormone (CRH), adrenocorticotropin releasing hormone (ACTH) and the release of cortisol (in humans and primates) or corticosterone (in rodents). The prolonged exposure to stress hormones may not only exacerbate pre-existing medical conditions including epilepsy, but may also increase the predisposition to psychiatric comorbidities. Hyperactivity of the HPA axis negatively impacts the structure and function of the temporal lobe of the brain, a region that is heavily involved in epilepsy and mood disorders like anxiety and depression. Seizures themselves damage temporal lobe structures, further disinhibiting the HPA axis, setting off a vicious cycle of neuronal damage and increasing susceptibility for subsequent seizures and psychiatric comorbidity. Treatments targeting the HPA axis may be beneficial both for epilepsy and for associated stress-related comorbidities such as anxiety or depression. This paper will highlight the evidence demonstrating dysfunction in the HPA axis associated with epilepsy which may contribute to the comorbidity of psychiatric disorders and epilepsy, and propose treatment strategies that may dually improve seizure control as well as alleviate stress related psychiatric comorbidities.
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Affiliation(s)
- Trina Basu
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA 02111, United States
| | - Jamie Maguire
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA 02111, United States
| | - Jay A Salpekar
- Kennedy Krieger Institute, Johns Hopkins University Medical School, Baltimore, MD 21205, United States.
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26
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Huo Y, Gao Y, Zheng Q, Zhao D, Guo T, Zhang S, Zeng Y, Cheng Y, Gu H, Zhang L, Zhu B, Luo H, Zhang X, Zhou Y, Zhang YW, Sun H, Xu H, Wang X. Overexpression of Human SNX27 Enhances Learning and Memory Through Modulating Synaptic Plasticity in Mice. Front Cell Dev Biol 2020; 8:595357. [PMID: 33330482 PMCID: PMC7729021 DOI: 10.3389/fcell.2020.595357] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Accepted: 11/11/2020] [Indexed: 11/13/2022] Open
Abstract
Abnormal synaptic transmission leads to learning and memory disorders and is the main feature of neurological diseases. Sorting nexin 27 (SNX27) is an endosomal adaptor protein associated with a variety of nervous system diseases, and it is mainly responsible for the trafficking of postsynaptic membrane receptors. However, the roles of SNX27 in regulating synaptic and cognitive function are not fully understood. Here, we first generated a neuron-specific human-SNX27 transgenic mouse model (hSNX27 Tg) that exhibited enhanced excitatory synaptic transmission and long-term potentiation (LTP). In addition, we found that the hSNX27 Tg mice displayed enhanced learning and memory, lower-level anxiety-like behavior, and increased social interaction. Furthermore, we found that SNX27 overexpression upregulated the expression of glutamate receptors in the cortex and hippocampus of hSNX27 Tg mice. Together, these results indicate that SNX27 overexpression promotes synaptic function and cognition through modulating glutamate receptors.
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Affiliation(s)
- Yuanhui Huo
- State Key Laboratory of Cellular Stress Biology, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, China
| | - Yue Gao
- State Key Laboratory of Cellular Stress Biology, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, China
| | - Qiuyang Zheng
- State Key Laboratory of Cellular Stress Biology, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, China
| | - Dongdong Zhao
- State Key Laboratory of Cellular Stress Biology, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, China
| | - Tiantian Guo
- State Key Laboratory of Cellular Stress Biology, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, China
| | - Shuo Zhang
- State Key Laboratory of Cellular Stress Biology, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, China
| | - Yuzhe Zeng
- State Key Laboratory of Cellular Stress Biology, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, China
| | - Yiyun Cheng
- State Key Laboratory of Cellular Stress Biology, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, China
| | - Huaping Gu
- State Key Laboratory of Cellular Stress Biology, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, China
| | - Lishan Zhang
- State Key Laboratory of Cellular Stress Biology, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, China
| | - Bin Zhu
- State Key Laboratory of Cellular Stress Biology, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, China
| | - Hong Luo
- State Key Laboratory of Cellular Stress Biology, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, China
| | - Xian Zhang
- State Key Laboratory of Cellular Stress Biology, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, China
| | - Ying Zhou
- National Institute for Data Science in Health and Medicine, School of Medicine, Xiamen University, Xiamen, China
| | - Yun-Wu Zhang
- State Key Laboratory of Cellular Stress Biology, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, China
| | - Hao Sun
- State Key Laboratory of Cellular Stress Biology, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, China
| | - Huaxi Xu
- State Key Laboratory of Cellular Stress Biology, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, China
| | - Xin Wang
- State Key Laboratory of Cellular Stress Biology, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, China
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Insights into Potential Targets for Therapeutic Intervention in Epilepsy. Int J Mol Sci 2020; 21:ijms21228573. [PMID: 33202963 PMCID: PMC7697405 DOI: 10.3390/ijms21228573] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 11/04/2020] [Accepted: 11/11/2020] [Indexed: 02/06/2023] Open
Abstract
Epilepsy is a chronic brain disease that affects approximately 65 million people worldwide. However, despite the continuous development of antiepileptic drugs, over 30% patients with epilepsy progress to drug-resistant epilepsy. For this reason, it is a high priority objective in preclinical research to find novel therapeutic targets and to develop effective drugs that prevent or reverse the molecular mechanisms underlying epilepsy progression. Among these potential therapeutic targets, we highlight currently available information involving signaling pathways (Wnt/β-catenin, Mammalian Target of Rapamycin (mTOR) signaling and zinc signaling), enzymes (carbonic anhydrase), proteins (erythropoietin, copine 6 and complement system), channels (Transient Receptor Potential Vanilloid Type 1 (TRPV1) channel) and receptors (galanin and melatonin receptors). All of them have demonstrated a certain degree of efficacy not only in controlling seizures but also in displaying neuroprotective activity and in modifying the progression of epilepsy. Although some research with these specific targets has been done in relation with epilepsy, they have not been fully explored as potential therapeutic targets that could help address the unsolved issue of drug-resistant epilepsy and develop new antiseizure therapies for the treatment of epilepsy.
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28
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Cannabidiol anticonvulsant effect is mediated by the PI3Kγ pathway. Neuropharmacology 2020; 176:108156. [DOI: 10.1016/j.neuropharm.2020.108156] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 05/19/2020] [Accepted: 05/20/2020] [Indexed: 12/21/2022]
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Novel brain permeant mTORC1/2 inhibitors are as efficacious as rapamycin or everolimus in mouse models of acquired partial epilepsy and tuberous sclerosis complex. Neuropharmacology 2020; 180:108297. [PMID: 32890589 DOI: 10.1016/j.neuropharm.2020.108297] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 08/27/2020] [Accepted: 09/01/2020] [Indexed: 12/24/2022]
Abstract
Mechanistic target of rapamycin (mTOR) regulates cell proliferation, growth and survival, and is activated in cancer and neurological disorders, including epilepsy. The rapamycin derivative ("rapalog") everolimus, which allosterically inhibits the mTOR pathway, is approved for the treatment of partial epilepsy with spontaneous recurrent seizures (SRS) in individuals with tuberous sclerosis complex (TSC). In contrast to the efficacy in TSC, the efficacy of rapalogs on SRS in other types of epilepsy is equivocal. Furthermore, rapalogs only poorly penetrate into the brain and are associated with peripheral adverse effects, which may compromise their therapeutic efficacy. Here we compare the antiseizure efficacy of two novel, brain-permeable ATP-competitive and selective mTORC1/2 inhibitors, PQR620 and PQR626, and the selective dual pan-PI3K/mTORC1/2 inhibitor PQR530 in two mouse models of chronic epilepsy with SRS, the intrahippocampal kainate (IHK) mouse model of acquired temporal lobe epilepsy and Tsc1GFAP CKO mice, a well-characterized mouse model of epilepsy in TSC. During prolonged treatment of IHK mice with rapamycin, everolimus, PQR620, PQR626, or PQR530; only PQR620 exerted a transient antiseizure effect on SRS, at well tolerated doses whereas the other compounds were ineffective. In contrast, all of the examined compounds markedly suppressed SRS in Tsc1GFAP CKO mice during chronic treatment at well tolerated doses. Thus, against our expectation, no clear differences in antiseizure efficacy were found across the three classes of mTOR inhibitors examined in mouse models of genetic and acquired epilepsies. The main advantage of the novel 1,3,5-triazine derivatives is their excellent tolerability compared to rapalogs, which would favor their development as new therapies for TORopathies such as TSC.
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Casillas‐Espinosa PM, Ali I, O'Brien TJ. Neurodegenerative pathways as targets for acquired epilepsy therapy development. Epilepsia Open 2020; 5:138-154. [PMID: 32524040 PMCID: PMC7278567 DOI: 10.1002/epi4.12386] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 02/13/2020] [Accepted: 02/24/2020] [Indexed: 12/16/2022] Open
Abstract
There is a growing body of clinical and experimental evidence that neurodegenerative diseases and epileptogenesis after an acquired brain insult may share common etiological mechanisms. Acquired epilepsy commonly develops as a comorbid condition in patients with neurodegenerative diseases such as Alzheimer's disease, although it is likely much under diagnosed in practice. Progressive neurodegeneration has also been described after traumatic brain injury, stroke, and other forms of brain insults. Moreover, recent evidence has shown that acquired epilepsy is often a progressive disorder that is associated with the development of drug resistance, cognitive decline, and worsening of other neuropsychiatric comorbidities. Therefore, new pharmacological therapies that target neurobiological pathways that underpin neurodegenerative diseases have potential to have both an anti-epileptogenic and disease-modifying effect on the seizures in patients with acquired epilepsy, and also mitigate the progressive neurocognitive and neuropsychiatric comorbidities. Here, we review the neurodegenerative pathways that are plausible targets for the development of novel therapies that could prevent the development or modify the progression of acquired epilepsy, and the supporting published experimental and clinical evidence.
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Affiliation(s)
- Pablo M. Casillas‐Espinosa
- Departments of Neuroscience and MedicineCentral Clinical SchoolMonash UniversityMelbourneVic.Australia
- Department of MedicineThe Royal Melbourne HospitalThe University of MelbourneMelbourneVic.Australia
| | - Idrish Ali
- Departments of Neuroscience and MedicineCentral Clinical SchoolMonash UniversityMelbourneVic.Australia
- Department of MedicineThe Royal Melbourne HospitalThe University of MelbourneMelbourneVic.Australia
| | - Terence J. O'Brien
- Departments of Neuroscience and MedicineCentral Clinical SchoolMonash UniversityMelbourneVic.Australia
- Department of MedicineThe Royal Melbourne HospitalThe University of MelbourneMelbourneVic.Australia
- Department of NeurologyThe Alfred HospitalMelbourneVic.Australia
- Department of NeurologyThe Royal Melbourne HospitalParkvilleVic.Australia
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31
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Yue J, Wei YJ, Yang XL, Liu SY, Yang H, Zhang C‐Q. NLRP3 inflammasome and endoplasmic reticulum stress in the epileptogenic zone in temporal lobe epilepsy: molecular insights into their interdependence. Neuropathol Appl Neurobiol 2020; 46:770-785. [PMID: 32311777 DOI: 10.1111/nan.12621] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 03/25/2020] [Accepted: 04/09/2020] [Indexed: 02/06/2023]
Affiliation(s)
- J. Yue
- Epilepsy Research Center of PLA Department of Neurosurgery Xinqiao Hospital Army Medical University Chongqing China
| | - Y. J. Wei
- Epilepsy Research Center of PLA Department of Neurosurgery Xinqiao Hospital Army Medical University Chongqing China
| | - X. L. Yang
- Epilepsy Research Center of PLA Department of Neurosurgery Xinqiao Hospital Army Medical University Chongqing China
| | - S. Y. Liu
- Epilepsy Research Center of PLA Department of Neurosurgery Xinqiao Hospital Army Medical University Chongqing China
| | - H. Yang
- Epilepsy Research Center of PLA Department of Neurosurgery Xinqiao Hospital Army Medical University Chongqing China
| | - C. ‐Q. Zhang
- Epilepsy Research Center of PLA Department of Neurosurgery Xinqiao Hospital Army Medical University Chongqing China
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Miziak B, Konarzewska A, Ułamek-Kozioł M, Dudra-Jastrzębska M, Pluta R, Czuczwar SJ. Anti-Epileptogenic Effects of Antiepileptic Drugs. Int J Mol Sci 2020; 21:ijms21072340. [PMID: 32231010 PMCID: PMC7178140 DOI: 10.3390/ijms21072340] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2020] [Revised: 03/23/2020] [Accepted: 03/25/2020] [Indexed: 12/12/2022] Open
Abstract
Generally, the prevalence of epilepsy does not exceed 0.9% of the population and approximately 70% of epilepsy patients may be adequately controlled with antiepileptic drugs (AEDs). Moreover, status epilepticus (SE) or even a single seizure may produce neurodegeneration within the brain and SE has been recognized as one of acute brain insults leading to acquired epilepsy via the process of epileptogenesis. Two questions thus arise: (1) Are AEDs able to inhibit SE-induced neurodegeneration? and (2) if so, can a probable neuroprotective potential of particular AEDs stop epileptogenesis? An affirmative answer to the second question would practically point to the preventive potential of a given neuroprotective AED following acute brain insults. The available experimental data indicate that diazepam (at low and high doses), gabapentin, pregabalin, topiramate and valproate exhibited potent or moderate neuroprotective effects in diverse models of SE in rats. However, only diazepam (at high doses), gabapentin and pregabalin exerted some protective activity against acquired epilepsy (spontaneous seizures). As regards valproate, its effects on spontaneous seizures were equivocal. With isobolography, some supra-additive combinations of AEDs have been delineated against experimental seizures. One of such combinations, levetiracetam + topiramate proved highly synergistic in two models of seizures and this particular combination significantly inhibited epileptogenesis in rats following status SE. Importantly, no neuroprotection was evident. It may be strikingly concluded that there is no correlation between neuroprotection and antiepileptogenesis. Probably, preclinically verified combinations of AEDs may be considered for an anti-epileptogenic therapy.
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Affiliation(s)
- Barbara Miziak
- Department of Pathophysiology, Medical University of Lublin, 20-090 Lublin, Poland; (B.M.); (A.K.); (M.D.-J.)
| | - Agnieszka Konarzewska
- Department of Pathophysiology, Medical University of Lublin, 20-090 Lublin, Poland; (B.M.); (A.K.); (M.D.-J.)
| | - Marzena Ułamek-Kozioł
- Laboratory of Ischemic and Neurodegenerative Brain Research, Mossakowski Medical Research Centre, Polish Academy of Sciences, 02-106 Warsaw, Poland;
| | - Monika Dudra-Jastrzębska
- Department of Pathophysiology, Medical University of Lublin, 20-090 Lublin, Poland; (B.M.); (A.K.); (M.D.-J.)
| | - Ryszard Pluta
- Laboratory of Ischemic and Neurodegenerative Brain Research, Mossakowski Medical Research Centre, Polish Academy of Sciences, 02-106 Warsaw, Poland;
- Correspondence: (R.P.); (S.J.C.); Tel.: +48-22-6086-540 (ext. 6086-469) (R.P.); +48-81-448-65-00 (S.J.C.); Fax: +48-81-448-65-01 (S.J.C.); +48-22-6086-627/668-55-32 (R.P.)
| | - Stanisław J. Czuczwar
- Department of Pathophysiology, Medical University of Lublin, 20-090 Lublin, Poland; (B.M.); (A.K.); (M.D.-J.)
- Correspondence: (R.P.); (S.J.C.); Tel.: +48-22-6086-540 (ext. 6086-469) (R.P.); +48-81-448-65-00 (S.J.C.); Fax: +48-81-448-65-01 (S.J.C.); +48-22-6086-627/668-55-32 (R.P.)
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Hodges SL, Lugo JN. Therapeutic role of targeting mTOR signaling and neuroinflammation in epilepsy. Epilepsy Res 2020; 161:106282. [DOI: 10.1016/j.eplepsyres.2020.106282] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 01/03/2020] [Accepted: 01/29/2020] [Indexed: 02/08/2023]
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Crino PB. Mechanistic target of rapamycin (mTOR) signaling in status epilepticus. Epilepsy Behav 2019; 101:106550. [PMID: 31732331 DOI: 10.1016/j.yebeh.2019.106550] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2019] [Revised: 09/06/2019] [Accepted: 09/07/2019] [Indexed: 10/25/2022]
Abstract
The mechanistic target of rapamycin (mTOR) pathway plays a critical role in brain development, neuronal shape and size, and synaptic plasticity, as well as learning and memory. Mutations in mTOR pathway genes (MPG) cause malformations of cortical development (MCDs) that are highly associated with often intractable epilepsy, thus highlighting an association between the mTOR pathway and establishment of the epileptic network. A growing body of preclinical evidence in in vitro and rodent model systems suggests that mTOR signaling may be altered in status epilepticus (SE) and that modulation of mTOR activation with mTOR inhibitors such as rapamycin (sirolimus) could provide new therapeutic avenues for treatment of both refractory epilepsy and SE. Rapamycin may have ubiquitous effects on all neuronal subtypes as well as astrocytes and seems to prevent the development of seizures following experimentally induced SE. To date, there have been no human studies focused on mTOR signaling in SE, but clearly, preclinical data support investigation into this pivotal cell signaling pathway. Thus, modulation of the mTOR pathway may provide a new strategy for treatment of SE and could have implications for the prevention of epilepsy in patients with SE. This article is part of the Special Issue "Proceedings of the 7th London-Innsbruck Colloquium on Status Epilepticus and Acute Seizures".
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Affiliation(s)
- Peter B Crino
- Department of Neurology, University of Maryland School of Medicine, 110 S. Paca St., Baltimore, MD 21201, United States of America.
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35
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Soares JI, Da Costa C, Ferreira MH, Andrade PA, Maia GH, Lukoyanov NV. Partial depletion of septohippocampal cholinergic cells reduces seizure susceptibility, but does not mitigate hippocampal neurodegeneration in the kainate model of epilepsy. Brain Res 2019; 1717:235-246. [DOI: 10.1016/j.brainres.2019.04.027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2019] [Revised: 04/22/2019] [Accepted: 04/23/2019] [Indexed: 02/06/2023]
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Shiono S, Williamson J, Kapur J, Joshi S. Progesterone receptor activation regulates seizure susceptibility. Ann Clin Transl Neurol 2019; 6:1302-1310. [PMID: 31353848 PMCID: PMC6649646 DOI: 10.1002/acn3.50830] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 06/06/2019] [Accepted: 06/06/2019] [Indexed: 12/21/2022] Open
Abstract
OBJECTIVE Progesterone is a potent neuromodulator that exerts effects on the brain through neurosteroids, progesterone receptors (PRs), and other molecules. Whether PR activation regulates seizures is not known. We determined whether PR activation increased seizure susceptibility. METHODS Adult female rats that developed epilepsy following lithium-pilocarpine-induced status epilepticus (SE) were used. Seizures were recorded by continuous-video EEG and read by an individual blinded to the treatment of the animals. The animals were treated for a week with progesterone (50 mg/kg per day), and the effect of progesterone withdrawal on seizure frequency was assessed during the subsequent week. During the week of progesterone treatment, the animals were treated with PR antagonist RU-486 (10 mg/kg per day) or a vehicle control, which was administered 30 min before progesterone. In another set of animals, we determined the effect of the PR agonist Nestorone (3 mg/kg per day) on seizure frequency. The animals were treated with Nestorone or vehicle for a week, and seizure frequencies at baseline and during the treatment week were compared. RESULTS Progesterone withdrawal induced twofold increase in seizures in 57% of animals (n = 14). RU-486 treatment in combination with progesterone, prevented this increase, and a smaller fraction of animals (17%) experienced withdrawal seizures (n = 13). The specific activation of PRs by Nestorone also increased the seizure frequency. Forty-six percent (n = 14) of Nestorone-treated animals experienced at least a 50% increase in seizures compared to only 9% of the vehicle-treated animals (n = 11). INTERPRETATION PR activation increased seizure frequency in epileptic animals. Thus, PRs may be novel targets for treating catamenial epilepsy.
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Affiliation(s)
- Shinnosuke Shiono
- Department of NeurologyUniversity of VirginiaCharlottesvilleVirginia22908
| | - John Williamson
- Department of NeurologyUniversity of VirginiaCharlottesvilleVirginia22908
| | - Jaideep Kapur
- Department of NeurologyUniversity of VirginiaCharlottesvilleVirginia22908
- Department of NeuroscienceUniversity of VirginiaCharlottesvilleVirginia22908
- UVA Brain Institute, University of VirginiaCharlottesvilleVirginia22908
| | - Suchitra Joshi
- Department of NeurologyUniversity of VirginiaCharlottesvilleVirginia22908
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Cameron S, Lopez A, Glabman R, Abrams E, Johnson S, Field C, Gulland FMD, Buckmaster PS. Proportional loss of parvalbumin-immunoreactive synaptic boutons and granule cells from the hippocampus of sea lions with temporal lobe epilepsy. J Comp Neurol 2019; 527:2341-2355. [PMID: 30861128 DOI: 10.1002/cne.24680] [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: 12/19/2018] [Revised: 02/18/2019] [Accepted: 03/02/2019] [Indexed: 01/10/2023]
Abstract
One in 26 people develop epilepsy and in these temporal lobe epilepsy (TLE) is common. Many patients display a pattern of neuron loss called hippocampal sclerosis. Seizures usually start in the hippocampus but underlying mechanisms remain unclear. One possibility is insufficient inhibition of dentate granule cells. Normally parvalbumin-immunoreactive (PV) interneurons strongly inhibit granule cells. Humans with TLE display loss of PV interneurons in the dentate gyrus but questions persist. To address this, we evaluated PV interneuron and bouton numbers in California sea lions (Zalophus californianus) that naturally develop TLE after exposure to domoic acid, a neurotoxin that enters the marine food chain during harmful algal blooms. Sclerotic hippocampi were identified by the loss of Nissl-stained hilar neurons. Stereological methods were used to estimate the number of granule cells and PV interneurons per dentate gyrus. Sclerotic hippocampi contained fewer granule cells, fewer PV interneurons, and fewer PV synaptic boutons, and the ratio of granule cells to PV interneurons was higher than in controls. To test whether fewer boutons was attributable to loss versus reduced immunoreactivity, expression of synaptotagmin-2 (syt2) was evaluated. Syt2 is also expressed in boutons of PV interneurons. Sclerotic hippocampi displayed proportional losses of syt2-immunoreactive boutons, PV boutons, and granule cells. There was no significant difference in the average numbers of PV- or syt2-positive boutons per granule cell between control and sclerotic hippocampi. These findings do not address functionality of surviving synapses but suggest reduced granule cell inhibition in TLE is not attributable to anatomical loss of PV boutons.
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Affiliation(s)
- Starr Cameron
- Department of Comparative Medicine, Stanford University, Stanford, California
| | - Ariana Lopez
- Department of Comparative Medicine, Stanford University, Stanford, California.,College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina
| | - Raisa Glabman
- Department of Comparative Medicine, Stanford University, Stanford, California.,School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Emily Abrams
- Department of Comparative Medicine, Stanford University, Stanford, California
| | | | - Cara Field
- The Marine Mammal Center, Sausalito, California
| | | | - Paul S Buckmaster
- Department of Comparative Medicine, Stanford University, Stanford, California.,Department of Neurology & Neurological Sciences, Stanford University, Stanford, California
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Sears SMS, Hewett JA, Hewett SJ. Decreased epileptogenesis in mice lacking the System x c - transporter occurs in association with a reduction in AMPA receptor subunit GluA1. Epilepsia Open 2019; 4:133-143. [PMID: 30868123 PMCID: PMC6398109 DOI: 10.1002/epi4.12307] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Accepted: 01/19/2019] [Indexed: 12/18/2022] Open
Abstract
OBJECTIVE Although the cystine/glutamate antiporter System xc - (Sxc -) plays a permissive role in glioma-associated seizures, its contribution to other acquired epilepsies has not been determined. As such, the present study investigates whether and how Sxc - contributes to the pentylenetetrazole (PTZ) chemical kindling model of epileptogenesis. METHODS Male Sxc - null (sut/sut) mice and their wild-type littermates were administered PTZ (i.p.) daily for up to 21 days (kindling paradigm). Seizure severity was scored on a 5-point behavioral scale. Mossy fiber sprouting, cellular degeneration, and Sxc - light chain (xCT) messenger RNA (mRNA) were explored using Timm staining, thionin staining, and real-time quantitative polymerase chain reaction (qPCR), respectively. Levels of reduced and oxidized glutathione and cysteine were determined via high-performance liquid chromatography (HPLC). Plasma membrane protein levels of glutamate and γ-aminobutyric acid (GABA) receptor subunits as well as the K+/Cl- co-transporter KCC2 were quantified via western blot analysis. RESULTS Repeated administration of PTZ produced chemical kindling in only 50% of Sxc - null mice as compared to 82% of wild-type littermate control mice. Kindling did not result in any changes in xCT mRNA levels assessed in wild-type mice. No cellular degeneration or mossy fiber sprouting was discernible in either genotype. Except for a small, but significant, decrease in oxidized cysteine in the hippocampus, no other change in measured redox couples was determined in Sxc - null mice. Cortical levels of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor subunit GluA1 were decreased in Sxc - null mice as compared to wild-type littermates, whereas all other proteins tested showed no difference between genotypes. SIGNIFICANCE This study provides the first evidence that Sxc - signaling contributes to epileptogenesis in the PTZ kindling model of acquired epilepsy. Further data indicate that a reduction in AMPA receptor signaling could underlie the resistance to PTZ kindling uncovered in Sxc - null mice.
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Affiliation(s)
- Sheila M. S. Sears
- Department of BiologyProgram in NeuroscienceSyracuse UniversitySyracuseNew York
| | - James A. Hewett
- Department of BiologyProgram in NeuroscienceSyracuse UniversitySyracuseNew York
| | - Sandra J. Hewett
- Department of BiologyProgram in NeuroscienceSyracuse UniversitySyracuseNew York
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Zhu G, Meng D, Chen Y, Du T, Liu Y, Liu D, Shi L, Jiang Y, Zhang X, Zhang J. Anterior nucleus of thalamus stimulation inhibited abnormal mossy fiber sprouting in kainic acid-induced epileptic rats. Brain Res 2018; 1701:28-35. [DOI: 10.1016/j.brainres.2018.07.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 06/25/2018] [Accepted: 07/12/2018] [Indexed: 12/11/2022]
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40
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Cavarsan CF, Malheiros J, Hamani C, Najm I, Covolan L. Is Mossy Fiber Sprouting a Potential Therapeutic Target for Epilepsy? Front Neurol 2018; 9:1023. [PMID: 30555406 PMCID: PMC6284045 DOI: 10.3389/fneur.2018.01023] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 11/13/2018] [Indexed: 11/13/2022] Open
Abstract
Mesial temporal lobe epilepsy (MTLE) caused by hippocampal sclerosis is one of the most frequent focal epilepsies in adults. It is characterized by focal seizures that begin in the hippocampus, sometimes spread to the insulo-perisylvian regions and may progress to secondary generalized seizures. Morphological alterations in hippocampal sclerosis are well defined. Among them, hippocampal sclerosis is characterized by prominent cell loss in the hilus and CA1, and abnormal mossy fiber sprouting (granular cell axons) into the dentate gyrus inner molecular layer. In this review, we highlight the role of mossy fiber sprouting in seizure generation and hippocampal excitability and discuss the response of alternative treatment strategies in terms of MFS and spontaneous recurrent seizures in models of TLE (temporal lobe epilepsy).
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Affiliation(s)
- Clarissa F Cavarsan
- Department of Physiology, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Jackeline Malheiros
- Department of Physiology, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Clement Hamani
- Department of Physiology, Universidade Federal de São Paulo, São Paulo, Brazil.,Harquail Centre for Neuromodulation, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, ON, Canada
| | - Imad Najm
- Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, OH, United States
| | - Luciene Covolan
- Department of Physiology, Universidade Federal de São Paulo, São Paulo, Brazil.,Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, OH, United States
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Lalitha S, Minz RW, Medhi B. Understanding the controversial drug targets in epilepsy and pharmacoresistant epilepsy. Rev Neurosci 2018; 29:333-345. [PMID: 29211683 DOI: 10.1515/revneuro-2017-0043] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 08/11/2017] [Indexed: 12/18/2022]
Abstract
Accumulating experimental data suggests a number of successful drug targets against epilepsy which eventually failed in the clinical setup. Mammalian target of rapamycin inhibitors, multi-drug resistance transporter inhibitors, cyclo-oxygenase-2 inhibitors, statins, etc. are the most promising and well studied among them. Drugs aiming at these targets produced beneficial response in most of the in vitro and in vivo seizure models. However, in certain situations, they have produced differential rather controversial results. Their effects varied with the seizure model, species, time and route of administration, different drugs from the same class, etc. This review emphasises on such drugs which presented with variability in their beneficial effects against seizures and epilepsy. This review critically summarises the preclinical evidence of these targets in the context of seizures and the probable reasons for their variability and clinical failures.
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Affiliation(s)
- Sree Lalitha
- Department of Immunopathology, Postgraduate Institute of Medical Education and Research, Chandigarh 160012, India
| | - Ranjana W Minz
- Department of Immunopathology, Postgraduate Institute of Medical Education and Research, Chandigarh 160012, India
| | - Bikash Medhi
- Department of Pharmacology, Postgraduate Institute of Medical Education and Research, Chandigarh 160012, India
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42
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Targeting the Mouse Ventral Hippocampus in the Intrahippocampal Kainic Acid Model of Temporal Lobe Epilepsy. eNeuro 2018; 5:eN-NWR-0158-18. [PMID: 30131968 PMCID: PMC6102375 DOI: 10.1523/eneuro.0158-18.2018] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 06/08/2018] [Accepted: 06/29/2018] [Indexed: 11/21/2022] Open
Abstract
Here we describe a novel mouse model of temporal lobe epilepsy (TLE) that moves the site of kainate injection from the rodent dorsal hippocampus (corresponding to the human posterior hippocampus) to the ventral hippocampus (corresponding to the human anterior hippocampus). We compare the phenotypes of this new model—with respect to seizures, cognitive impairment, affective deficits, and histopathology—to the standard dorsal intrahippocampal kainate model. Our results demonstrate that histopathological measures of granule cell dispersion and mossy fiber sprouting maximize near the site of kainate injection. Somewhat surprisingly, both the dorsal and ventral models exhibit similar spatial memory impairments in addition to similar electrographic and behavioral seizure burdens. In contrast, we find a more pronounced affective (anhedonic) phenotype specifically in the ventral model. These results demonstrate that the ventral intrahippocampal kainic acid model recapitulates critical pathologies of the dorsal model while providing a means to further study affective phenotypes such as depression in TLE.
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Zhu X, Li X, Zhu M, Xu K, Yang L, Han B, Huang R, Zhang A, Yao H. Metalloprotease Adam10 suppresses epilepsy through repression of hippocampal neuroinflammation. J Neuroinflammation 2018; 15:221. [PMID: 30075790 PMCID: PMC6091106 DOI: 10.1186/s12974-018-1260-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 07/19/2018] [Indexed: 12/16/2022] Open
Abstract
Background Mice with pilocarpine-induced temporal lobe epilepsy (TLE) are characterized by intense hippocampal neuroinflammation, a prominent pathological hallmark of TLE that is known to contribute to neuronal hyperexcitability. Recent studies indicate that Adam10, a member of a disintegrin and metalloproteinase domain-containing protein (Adam) family, has been involved in the neuroinflammation response. However, it remains unclear whether and how Adam10 modulates neuroinflammation responses in the context of an epileptic brain or whether Adam10 affects epileptogenesis via the neuroinflammation pathway. Methods Adult male C57BL/6J mice were subjected to intraperitoneal injection of pilocarpine to induce TLE. Adeno-associated viral (AAV) vectors carrying Adam10 (AAV-Adam10) or lentiviral vectors carrying short hairpin RNA, which is specific to the mouse Adam10 mRNA (shRNA-Adam10), were bilaterally injected into the hippocampus to induce overexpression or knockdown of Adam10, respectively. The specific anti-inflammatory agent minocycline was administered following status epilepticus (SE) to block hippocampal neuroinflammation. Continuous video EEG recording was performed to analyze epileptic behavior. Western blot, immunofluorescence staining, and ELISA were performed to determine Adam10 expression as well as hippocampal neuroinflammation. Results In this study, we demonstrate that overexpression of Adam10 in the hippocampus suppresses neuroinflammation and reduces seizure activity in TLE mice, whereas knockdown of Adam10 exacerbates hippocampal neuroinflammation and increases seizure activity. Furthermore, increased seizure activity in Adam10 knockdown TLE mice is dependent on hippocampal neuroinflammation. Conclusion These results suggest that Adam10 suppresses epilepsy through repression of hippocampal neuroinflammation. Our findings provide new insights into the Adam10 regulation of development of epilepsy via the neuroinflammation pathway and identify a potential therapeutic target for epilepsy.
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Affiliation(s)
- Xinjian Zhu
- Department of Pharmacology, Medical School of Southeast University, Dingjiaqiao 87th, Nanjing, 210009, China.
| | - Xiaolin Li
- Department of Geriatrics, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Mengyi Zhu
- Department of Pharmacology, Medical School of Southeast University, Dingjiaqiao 87th, Nanjing, 210009, China
| | - Kangni Xu
- Department of Pharmacology, Medical School of Southeast University, Dingjiaqiao 87th, Nanjing, 210009, China
| | - Li Yang
- Department of Pharmacology, Medical School of Southeast University, Dingjiaqiao 87th, Nanjing, 210009, China
| | - Bing Han
- Department of Pharmacology, Medical School of Southeast University, Dingjiaqiao 87th, Nanjing, 210009, China
| | - Rongrong Huang
- Department of Pharmacology, Medical School of Southeast University, Dingjiaqiao 87th, Nanjing, 210009, China
| | - Aifeng Zhang
- Department of Pathology, Medical School of Southeast University, Nanjing, China
| | - Honghong Yao
- Department of Pharmacology, Medical School of Southeast University, Dingjiaqiao 87th, Nanjing, 210009, China
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Brandt C, Hillmann P, Noack A, Römermann K, Öhler LA, Rageot D, Beaufils F, Melone A, Sele AM, Wymann MP, Fabbro D, Löscher W. The novel, catalytic mTORC1/2 inhibitor PQR620 and the PI3K/mTORC1/2 inhibitor PQR530 effectively cross the blood-brain barrier and increase seizure threshold in a mouse model of chronic epilepsy. Neuropharmacology 2018; 140:107-120. [PMID: 30081001 DOI: 10.1016/j.neuropharm.2018.08.002] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Revised: 07/09/2018] [Accepted: 08/02/2018] [Indexed: 12/13/2022]
Abstract
The mTOR signaling pathway has emerged as a possible therapeutic target for epilepsy. Clinical trials have shown that mTOR inhibitors such as everolimus reduce seizures in tuberous sclerosis complex patients with intractable epilepsy. Furthermore, accumulating preclinical data suggest that mTOR inhibitors may have anti-seizure or anti-epileptogenic actions in other types of epilepsy. However, the chronic use of rapalogs such as everolimus is limited by poor tolerability, particularly by immunosuppression, poor brain penetration and induction of feedback loops which might contribute to their limited therapeutic efficacy. Here we describe two novel, brain-permeable and well tolerated small molecule 1,3,5-triazine derivatives, the catalytic mTORC1/C2 inhibitor PQR620 and the dual pan-PI3K/mTOR inhibitor PQR530. These derivatives were compared with the mTORC1 inhibitors rapamycin and everolimus as well as the anti-seizure drugs phenobarbital and levetiracetam. The anti-seizure potential of these compounds was determined by evaluating the electroconvulsive seizure threshold in normal and epileptic mice. Rapamycin and everolimus only poorly penetrated into the brain (brain:plasma ratio 0.0057 for rapamycin and 0.016 for everolimus). In contrast, the novel compounds rapidly entered the brain, reaching brain:plasma ratios of ∼1.6. Furthermore, they significantly decreased phosphorylation of S6 ribosomal protein in the hippocampus of normal and epileptic mice, demonstrating effective mTOR inhibition. PQR620 and PQR530 significantly increased seizure threshold at tolerable doses. The effect of PQR620 was more marked in epileptic vs. nonepileptic mice, matching the efficacy of levetiracetam. Overall, the novel compounds described here have the potential to overcome the disadvantages of rapalogs for treatment of epilepsy and mTORopathies directly connected to mutations in the mTOR signaling cascade.
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Affiliation(s)
- Claudia Brandt
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany; Center for Systems Neuroscience, Hannover, Germany
| | | | - Andreas Noack
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany; Center for Systems Neuroscience, Hannover, Germany
| | - Kerstin Römermann
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany; Center for Systems Neuroscience, Hannover, Germany
| | - Leon A Öhler
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany
| | - Denise Rageot
- Department of Biomedicine, University of Basel, Basel, Switzerland
| | | | - Anna Melone
- Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Alexander M Sele
- Department of Biomedicine, University of Basel, Basel, Switzerland
| | | | | | - Wolfgang Löscher
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany; Center for Systems Neuroscience, Hannover, Germany.
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Godale CM, Danzer SC. Signaling Pathways and Cellular Mechanisms Regulating Mossy Fiber Sprouting in the Development of Epilepsy. Front Neurol 2018; 9:298. [PMID: 29774009 PMCID: PMC5943493 DOI: 10.3389/fneur.2018.00298] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 04/17/2018] [Indexed: 02/04/2023] Open
Abstract
The sprouting of hippocampal dentate granule cell axons, termed mossy fibers, into the dentate inner molecular layer is one of the most consistent findings in tissue from patients with mesial temporal lobe epilepsy. Decades of research in animal models have revealed that mossy fiber sprouting creates de novo recurrent excitatory connections in the hippocampus, fueling speculation that the pathology may drive temporal lobe epileptogenesis. Conducting definitive experiments to test this hypothesis, however, has been challenging due to the difficulty of dissociating this sprouting from the many other changes occurring during epileptogenesis. The field has been largely driven, therefore, by correlative data. Recently, the development of powerful transgenic mouse technologies and the discovery of novel drug targets has provided new tools to assess the role of mossy fiber sprouting in epilepsy. We can now selectively manipulate hippocampal granule cells in rodent epilepsy models, providing new insights into the granule cell subpopulations that participate in mossy fiber sprouting. The cellular pathways regulating this sprouting are also coming to light, providing new targets for pharmacological intervention. Surprisingly, many investigators have found that blocking mossy fiber sprouting has no effect on seizure occurrence, while seizure frequency can be reduced by treatments that have no effect on this sprouting. These results raise new questions about the role of mossy fiber sprouting in epilepsy. Here, we will review these findings with particular regard to the contributions of new granule cells to mossy fiber sprouting and the regulation of this sprouting by the mTOR signaling pathway.
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Affiliation(s)
- Christin M Godale
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States.,Neuroscience Graduate Program, University of Cincinnati, Cincinnati, OH, United States
| | - Steve C Danzer
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States.,Neuroscience Graduate Program, University of Cincinnati, Cincinnati, OH, United States.,Department of Anesthesia, University of Cincinnati, Cincinnati, OH, United States.,Department of Pediatrics, University of Cincinnati, Cincinnati, OH, United States
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Abstract
Epilepsy affects all age groups and is one of the most common and most disabling neurological disorders. The accurate diagnosis of seizures is essential as some patients will be misdiagnosed with epilepsy, whereas others will receive an incorrect diagnosis. Indeed, errors in diagnosis are common, and many patients fail to receive the correct treatment, which often has severe consequences. Although many patients have seizure control using a single medication, others require multiple medications, resective surgery, neuromodulation devices or dietary therapies. In addition, one-third of patients will continue to have uncontrolled seizures. Epilepsy can substantially impair quality of life owing to seizures, comorbid mood and psychiatric disorders, cognitive deficits and adverse effects of medications. In addition, seizures can be fatal owing to direct effects on autonomic and arousal functions or owing to indirect effects such as drowning and other accidents. Deciphering the pathophysiology of epilepsy has advanced the understanding of the cellular and molecular events initiated by pathogenetic insults that transform normal circuits into epileptic circuits (epileptogenesis) and the mechanisms that generate seizures (ictogenesis). The discovery of >500 genes associated with epilepsy has led to new animal models, more precise diagnoses and, in some cases, targeted therapies.
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Affiliation(s)
- Orrin Devinsky
- Departments of Neurology, Neuroscience, Neurosurgery and Psychiatry, NYU School of Medicine, New York, NY, USA
| | - Annamaria Vezzani
- Laboratory of Experimental Neurology, Department of Neuroscience, IRCCS 'Mario Negri' Institute for Pharmacological Research, Milan, Italy
| | - Terence J O'Brien
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Victoria, Australia.,Department of Neurology, Alfred Health, Melbourne, Victoria, Australia.,Departments of Neurology and Medicine, The Royal Melbourne Hospital, The University of Melbourne, Melbourne, Victoria, Australia
| | - Nathalie Jette
- Department of Neurology and Department of Population Health Science and Policy, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Ingrid E Scheffer
- Epilepsy Research Centre, Department of Medicine, Austin Health, The University of Melbourne, Melbourne, Victoria, Australia.,The Florey Institute of Neuroscience and Mental Health, Melbourne, Victoria, Australia.,Department of Paediatrics, The University of Melbourne, and Department of Neurology, The Royal Children's Hospital, Melbourne, Victoria, Australia
| | - Marco de Curtis
- Epilepsy Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Piero Perucca
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Victoria, Australia.,Department of Neurology, Alfred Health, Melbourne, Victoria, Australia.,Departments of Neurology and Medicine, The Royal Melbourne Hospital, The University of Melbourne, Melbourne, Victoria, Australia
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Demars F, Clark K, Wyeth MS, Abrams E, Buckmaster PS. A single subconvulsant dose of domoic acid at mid-gestation does not cause temporal lobe epilepsy in mice. Neurotoxicology 2018; 66:128-137. [PMID: 29625197 PMCID: PMC5940543 DOI: 10.1016/j.neuro.2018.04.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Revised: 03/28/2018] [Accepted: 04/02/2018] [Indexed: 11/19/2022]
Abstract
Harmful blooms of domoic acid (DA)-producing algae are a problem in oceans worldwide. DA is a potent glutamate receptor agonist that can cause status epilepticus and in survivors, temporal lobe epilepsy. In mice, one-time low-dose in utero exposure to DA was reported to cause hippocampal damage and epileptiform activity, leading to the hypothesis that unrecognized exposure to DA from contaminated seafood in pregnant women can damage the fetal hippocampus and initiate temporal lobe epileptogenesis. However, development of epilepsy (i.e., spontaneous recurrent seizures) has not been tested. In the present study, long-term seizure monitoring and histology was used to test for temporal lobe epilepsy following prenatal exposure to DA. In Experiment One, the previous study's in utero DA treatment protocol was replicated, including use of the CD-1 mouse strain. Afterward, mice were video-monitored for convulsive seizures from 2 to 6 months old. None of the CD-1 mice treated in utero with vehicle or DA was observed to experience spontaneous convulsive seizures. After seizure monitoring, mice were evaluated for pathological evidence of temporal lobe epilepsy. None of the mice treated in utero with DA displayed the hilar neuron loss that occurs in patients with temporal lobe epilepsy and in the mouse pilocarpine model of temporal lobe epilepsy. In Experiment Two, a higher dose of DA was administered to pregnant FVB mice. FVB mice were tested as a potentially more sensitive strain, because they have a lower seizure threshold, and some females spontaneously develop epilepsy. Female offspring were monitored with continuous video and telemetric bilateral hippocampal local field potential recording at 1-11 months old. A similar proportion of vehicle- and DA-treated female FVB mice spontaneously developed epilepsy, beginning in the fourth month of life. Average seizure frequency and duration were similar in both groups. Seizure frequency was lower than that of positive-control pilocarpine-treated mice, but seizure duration was similar. None of the mice treated in utero with vehicle or DA displayed hilar neuron loss or intense mossy fiber sprouting, a form of aberrant synaptic reorganization that develops in patients with temporal lobe epilepsy and in pilocarpine-treated mice. FVB mice that developed epilepsy (vehicle- and DA-treated) displayed mild mossy fiber sprouting. Results of this study suggest that a single subconvulsive dose of DA at mid-gestation does not cause temporal lobe epilepsy in mice.
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Affiliation(s)
- Fanny Demars
- Department of Comparative Medicine, School of Medicine, Stanford University, Stanford, CA, United States; VetAgro Sup, School of Veterinary Medicine, Lyon, France; Paris Descartes University, Paris, France
| | - Kristen Clark
- Department of Comparative Medicine, School of Medicine, Stanford University, Stanford, CA, United States; College of Veterinary Medicine, Oklahoma State University, Stillwater, OK, United States
| | - Megan S Wyeth
- Department of Comparative Medicine, School of Medicine, Stanford University, Stanford, CA, United States
| | - Emily Abrams
- Department of Comparative Medicine, School of Medicine, Stanford University, Stanford, CA, United States
| | - Paul S Buckmaster
- Department of Comparative Medicine, School of Medicine, Stanford University, Stanford, CA, United States; Department of Neurology & Neurological Sciences, School of Medicine, Stanford University, Stanford, CA, United States.
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RNA Polymerase 1 Is Transiently Regulated by Seizures and Plays a Role in a Pharmacological Kindling Model of Epilepsy. Mol Neurobiol 2018; 55:8374-8387. [PMID: 29546592 DOI: 10.1007/s12035-018-0989-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Accepted: 03/06/2018] [Indexed: 12/21/2022]
Abstract
Ribosome biogenesis, including the RNA polymerase 1 (Pol1)-mediated transcription of rRNA, is regulated by the pro-epileptogenic mTOR pathway. Therefore, hippocampal Pol1 activity was examined in mouse models of epilepsy including kainic acid- and pilocarpine-induced status epilepticus (SE) as well as a single seizure in response to pentylenetetrazole (PTZ). Elevated 47S pre-rRNA levels were present acutely after induction of SE suggesting activation of Pol1. Conversely, after a single seizure, 47S pre-rRNA was transiently downregulated with increased levels of unprocessed 18S rRNA precursors in the cornu Ammonis (CA) region. At least in the dentate gyrus (DG), the pilocarpine SE-mediated transient activation of Pol1 did not translate into long-term changes of pre-rRNA levels or total ribosome content. Unaltered hippocampal ribosome content was also found after a 20-day PTZ kindling paradigm with increasing pro-convulsive effects of low dose PTZ that was injected every other day. However, after selectively deleting the essential Pol1 co-activator, transcription initiation factor-1A (Tif1a/Rrn3) from excitatory neurons, PTZ kindling was impaired while DG total ribosome content was moderately reduced and no major neurodegeneration was observed throughout the hippocampus. Therefore, Pol1 activity of excitatory neurons is required for PTZ kindling. As seizures affect ribosome biogenesis without long-term effects on the total ribosome content, such a requirement may be associated with a need to produce specialized ribosomes that promote pro-epileptic plasticity.
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49
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Yan S, Zhang H, Xie W, Meng F, Zhang K, Jiang Y, Zhang X, Zhang J. Altered microRNA profiles in plasma exosomes from mesial temporal lobe epilepsy with hippocampal sclerosis. Oncotarget 2018; 8:4136-4146. [PMID: 27926529 PMCID: PMC5354818 DOI: 10.18632/oncotarget.13744] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 11/23/2016] [Indexed: 12/24/2022] Open
Abstract
Mesial temporal lobe epilepsy with hippocampal sclerosis (mTLE-HS) is the most common type of focal epilepsy. The present study aimed to explore the expression and functions of exosomal microRNAs in mTLE-HS. A total of 50 microRNAs were found to be differentially expressed in mTLE-HS compared with healthy controls. Among them, 2 were increased and 48 were decreased. The 6 significant differentially expressed candidate microRNAs (miR-3613-5p, miR-4668-5p, miR-8071, miR-197-5p, miR-4322, and miR-6781-5p ) in exosome were validated. The bioinformatics analysis showed that the potential target genes of these microRNAs were involved in biological processes, molecular functions, and cellular components. Similarly, these microRNAs also affected axon guidance, pathways in cancer, regulation of the actin cytoskeleton, focal adhesion, the calcium signaling pathway, the MAPK signaling pathway, and the PI3K-Akt signaling pathway. Among 6 candidate microRNAs, miR-8071 had the best diagnostic value for mTLE-HS with 83.33% sensitivity and 96.67% specificity, and was associated with seizure severity. This study indicated that exosomal microRNAs, may be regulators for the seizure development in mTLE-HS, and can be used as potential therapeutic targets and biomarker for diagnosis in mTLE-HS.
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Affiliation(s)
- Shaofeng Yan
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Hua Zhang
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Wenyan Xie
- Department of Clinical Laboratory, Qian Fo Shan Hospital of Shandong Province, Jinan, Shandong Province, China
| | - Fangang Meng
- Department of Functional Neurosurgery, Beijing Neurosurgical Institute, Capital Medical University, Beijing, China
| | - Kai Zhang
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Yin Jiang
- Department of Functional Neurosurgery, Beijing Neurosurgical Institute, Capital Medical University, Beijing, China
| | - Xin Zhang
- Department of Functional Neurosurgery, Beijing Neurosurgical Institute, Capital Medical University, Beijing, China
| | - Jianguo Zhang
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.,Department of Functional Neurosurgery, Beijing Neurosurgical Institute, Capital Medical University, Beijing, China
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50
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Becker AJ. Review: Animal models of acquired epilepsy: insights into mechanisms of human epileptogenesis. Neuropathol Appl Neurobiol 2018; 44:112-129. [DOI: 10.1111/nan.12451] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 10/27/2017] [Indexed: 02/06/2023]
Affiliation(s)
- A. J. Becker
- Section for Translational Epilepsy Research; Department of Neuropathology; University of Bonn Medical Center; Bonn Germany
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