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Dell'isola GB, Verrotti A, Sciaccaluga M, Roberti R, Parnetti L, Russo E, Costa C. Evaluating bexicaserin for the treatment of developmental epileptic encephalopathies. Expert Opin Pharmacother 2024; 25:1121-1130. [PMID: 38916481 DOI: 10.1080/14656566.2024.2373350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2024] [Accepted: 06/24/2024] [Indexed: 06/26/2024]
Abstract
INTRODUCTION Developmental epileptic encephalopathies (DEEs) pose significant challenges due to their refractory nature and limited treatment options. Despite advancements in genetic understanding, effective therapies targeting underlying pathophysiology are lacking. Serotoninergic dysfunction has been implicated in epilepsy, sparking interest in serotonin as a therapeutic target. AREA COVERED This article explores the potential of bexicaserin, a selective 5-HT2C receptor agonist, as an adjunctive antiseizure medication in DEEs. Bexicaserin is thought to modulate GABAergic neurotransmission, suppressing central hyperexcitability. Preclinical studies demonstrate its efficacy across various seizure models. Clinical trials, including the Pacific Study, reveal promising results in reducing motor seizures. However, challenges such as adverse effects and treatment discontinuation underscore the need for further investigation. EXPERT OPINION The efficacy of 5-HT2C serotoninergic agonists, validated in preclinical and clinical studies, highlights serotonin's role in DEEs. Bexicaserin offers new therapeutic possibilities, potentially synergizing with existing antiseizure medications. Polypharmacotherapy, targeting distinct pathways, may enhance therapeutic outcomes. Monitoring pharmacological interactions and addressing central nervous system comorbidities are crucial for optimizing treatment strategies. Further research is needed to elucidate bexicaserin's mechanisms and potential antiepileptogenic effects.
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Affiliation(s)
| | | | - Miriam Sciaccaluga
- Section of Neurology, Laboratory of Experimental Neurology, Department of Medicine and Surgery, University of Perugia, Perugia, Italy
- Mauro Baschirotto Rare Disease Foundation BIRD Onlus, Longare, VI, Italy
| | - Roberta Roberti
- Science of Health Department, University Magna Grecia of Catanzaro, Catanzaro, Italy
| | - Lucilla Parnetti
- Section of Neurology, Laboratory of Experimental Neurology, Department of Medicine and Surgery, University of Perugia, Perugia, Italy
| | - Emilio Russo
- Science of Health Department, University Magna Grecia of Catanzaro, Catanzaro, Italy
| | - Cinzia Costa
- Section of Neurology, Laboratory of Experimental Neurology, Department of Medicine and Surgery, University of Perugia, Perugia, Italy
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Brenet A, Somkhit J, Csaba Z, Ciura S, Kabashi E, Yanicostas C, Soussi-Yanicostas N. Microglia Mitigate Neuronal Activation in a Zebrafish Model of Dravet Syndrome. Cells 2024; 13:684. [PMID: 38667299 PMCID: PMC11049242 DOI: 10.3390/cells13080684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Revised: 04/05/2024] [Accepted: 04/07/2024] [Indexed: 04/28/2024] Open
Abstract
It has been known for a long time that epileptic seizures provoke brain neuroinflammation involving the activation of microglial cells. However, the role of these cells in this disease context and the consequences of their inflammatory activation on subsequent neuron network activity remain poorly understood so far. To fill this gap of knowledge and gain a better understanding of the role of microglia in the pathophysiology of epilepsy, we used an established zebrafish Dravet syndrome epilepsy model based on Scn1Lab sodium channel loss-of-function, combined with live microglia and neuronal Ca2+ imaging, local field potential (LFP) recording, and genetic microglia ablation. Data showed that microglial cells in scn1Lab-deficient larvae experiencing epileptiform seizures displayed morphological and biochemical changes characteristic of M1-like pro-inflammatory activation; i.e., reduced branching, amoeboid-like morphology, and marked increase in the number of microglia expressing pro-inflammatory cytokine Il1β. More importantly, LFP recording, Ca2+ imaging, and swimming behavior analysis showed that microglia-depleted scn1Lab-KD larvae displayed an increase in epileptiform seizure-like neuron activation when compared to that seen in scn1Lab-KD individuals with microglia. These findings strongly suggest that despite microglia activation and the synthesis of pro-inflammatory cytokines, these cells provide neuroprotective activities to epileptic neuronal networks, making these cells a promising therapeutic target in epilepsy.
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Affiliation(s)
- Alexandre Brenet
- NeuroDiderot, INSERM U1141, Université Paris Cité, Robert Debré Hospital, 75019 Paris, France
| | - Julie Somkhit
- NeuroDiderot, INSERM U1141, Université Paris Cité, Robert Debré Hospital, 75019 Paris, France
| | - Zsolt Csaba
- NeuroDiderot, INSERM U1141, Université Paris Cité, Robert Debré Hospital, 75019 Paris, France
| | - Sorana Ciura
- Institut Imagine, University Paris Descartes, Necker-Enfants Malades Hospital, 75015 Paris, France
| | - Edor Kabashi
- Institut Imagine, University Paris Descartes, Necker-Enfants Malades Hospital, 75015 Paris, France
| | - Constantin Yanicostas
- NeuroDiderot, INSERM U1141, Université Paris Cité, Robert Debré Hospital, 75019 Paris, France
- INSERM, T3S, Department of Biochemistry, Université Paris Cité, 75006 Paris, France
| | - Nadia Soussi-Yanicostas
- NeuroDiderot, INSERM U1141, Université Paris Cité, Robert Debré Hospital, 75019 Paris, France
- INSERM, T3S, Department of Biochemistry, Université Paris Cité, 75006 Paris, France
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Del Pozo A, Knox KM, Lehmann LM, Davidson S, Rho SL, Jayadev S, Barker-Haliski M. Chronic evoked seizures in young pre-symptomatic APP/PS1 mice induce serotonin changes and accelerate onset of Alzheimer's disease-related neuropathology. Prog Neurobiol 2024; 235:102591. [PMID: 38484965 PMCID: PMC11015961 DOI: 10.1016/j.pneurobio.2024.102591] [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: 10/31/2023] [Revised: 02/29/2024] [Accepted: 03/05/2024] [Indexed: 03/18/2024]
Abstract
OBJECTIVE Hyperexcitability is intimately linked to Alzheimer's disease (AD) pathology, but the precise timing and contributions of neuronal hyperexcitability to disease progression is unclear. Seizure induction in rodent AD models can uncover new therapeutic targets. Further, investigator-evoked seizures can directly establish how hyperexcitability and AD-associated risk factors influence neuropathological hallmarks and disease course at presymptomatic stages. METHODS Corneal kindling is a well-characterized preclinical epilepsy model that allows for precise control of seizure history to pair to subsequent behavioral assessments. 2-3-month-old APP/PS1, PSEN2-N141I, and transgenic control male and female mice were thus sham or corneal kindled for 2 weeks. Seizure-induced changes in glia, serotonin pathway proteins, and amyloid β levels in hippocampus and prefrontal cortex were quantified. RESULTS APP/PS1 females were more susceptible to corneal kindling. However, regardless of sex, APP/PS1 mice experienced extensive seizure-induced mortality versus kindled Tg- controls. PSEN2-N141I mice were not negatively affected by corneal kindling. Mortality correlated with a marked downregulation of hippocampal tryptophan hydroxylase 2 and monoamine oxidase A protein expression versus controls; these changes were not detected in PSEN2-N141I mice. Kindled APP/PS1 mice also exhibited soluble amyloid β upregulation and glial reactivity without plaque deposition. SIGNIFICANCE Evoked convulsive seizures and neuronal hyperexcitability in pre-symptomatic APP/PS1 mice promoted premature mortality without pathological Aβ plaque deposition, whereas PSEN2-N141I mice were unaffected. Disruptions in serotonin pathway metabolism in APP/PS1 mice was associated with increased glial reactivity without Aβ plaque deposition, demonstrating that neuronal hyperexcitability in early AD causes pathological Aβ overexpression and worsens long-term outcomes through a serotonin-related mechanism.
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Affiliation(s)
- Aaron Del Pozo
- Center for Epilepsy Drug Discovery (CEDD), Department of Pharmacy, University of Washington, Seattle, WA 98195, USA
| | - Kevin M Knox
- Center for Epilepsy Drug Discovery (CEDD), Department of Pharmacy, University of Washington, Seattle, WA 98195, USA
| | - Leanne M Lehmann
- Center for Epilepsy Drug Discovery (CEDD), Department of Pharmacy, University of Washington, Seattle, WA 98195, USA
| | - Stephanie Davidson
- Center for Epilepsy Drug Discovery (CEDD), Department of Pharmacy, University of Washington, Seattle, WA 98195, USA
| | - Seongheon Leo Rho
- Center for Epilepsy Drug Discovery (CEDD), Department of Pharmacy, University of Washington, Seattle, WA 98195, USA
| | - Suman Jayadev
- Department of Neurology, University of Washington, Seattle, WA 98195, USA
| | - Melissa Barker-Haliski
- Center for Epilepsy Drug Discovery (CEDD), Department of Pharmacy, University of Washington, Seattle, WA 98195, USA.
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Locubiche S, Ordóñez V, Abad E, Scotto di Mase M, Di Donato V, De Santis F. A Zebrafish-Based Platform for High-Throughput Epilepsy Modeling and Drug Screening in F0. Int J Mol Sci 2024; 25:2991. [PMID: 38474238 DOI: 10.3390/ijms25052991] [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: 11/20/2023] [Revised: 02/22/2024] [Accepted: 02/29/2024] [Indexed: 03/14/2024] Open
Abstract
The zebrafish model has emerged as a reference tool for phenotypic drug screening. An increasing number of molecules have been brought from bench to bedside thanks to zebrafish-based assays over the last decade. The high homology between the zebrafish and the human genomes facilitates the generation of zebrafish lines carrying loss-of-function mutations in disease-relevant genes; nonetheless, even using this alternative model, the establishment of isogenic mutant lines requires a long generation time and an elevated number of animals. In this study, we developed a zebrafish-based high-throughput platform for the generation of F0 knock-out (KO) models and the screening of neuroactive compounds. We show that the simultaneous inactivation of a reporter gene (tyrosinase) and a second gene of interest allows the phenotypic selection of F0 somatic mutants (crispants) carrying the highest rates of mutations in both loci. As a proof of principle, we targeted genes associated with neurodevelopmental disorders and we efficiently generated de facto F0 mutants in seven genes involved in childhood epilepsy. We employed a high-throughput multiparametric behavioral analysis to characterize the response of these KO models to an epileptogenic stimulus, making it possible to employ kinematic parameters to identify seizure-like events. The combination of these co-injection, screening and phenotyping methods allowed us to generate crispants recapitulating epilepsy features and to test the efficacy of compounds already during the first days post fertilization. Since the strategy can be applied to a wide range of indications, this study paves the ground for high-throughput drug discovery and promotes the use of zebrafish in personalized medicine and neurotoxicity assessment.
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Affiliation(s)
- Sílvia Locubiche
- ZeClinics S.L., Carrer de Laureà Miró, 408-410, 08980 Sant Feliu de Llobregat, Spain
- Faculty of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, 08036 Barcelona, Spain
| | - Víctor Ordóñez
- ZeClinics S.L., Carrer de Laureà Miró, 408-410, 08980 Sant Feliu de Llobregat, Spain
| | - Elena Abad
- ZeClinics S.L., Carrer de Laureà Miró, 408-410, 08980 Sant Feliu de Llobregat, Spain
| | | | - Vincenzo Di Donato
- ZeClinics S.L., Carrer de Laureà Miró, 408-410, 08980 Sant Feliu de Llobregat, Spain
| | - Flavia De Santis
- ZeClinics S.L., Carrer de Laureà Miró, 408-410, 08980 Sant Feliu de Llobregat, Spain
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Auvin S, Galanopoulou AS, Moshé SL, Potschka H, Rocha L, Walker MC. Revisiting the concept of drug-resistant epilepsy: A TASK1 report of the ILAE/AES Joint Translational Task Force. Epilepsia 2023; 64:2891-2908. [PMID: 37676719 PMCID: PMC10836613 DOI: 10.1111/epi.17751] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 08/08/2023] [Accepted: 08/16/2023] [Indexed: 09/08/2023]
Abstract
Despite progress in the development of anti-seizure medications (ASMs), one third of people with epilepsy have drug-resistant epilepsy (DRE). The working definition of DRE, proposed by the International League Against Epilepsy (ILAE) in 2010, helped identify individuals who might benefit from presurgical evaluation early on. As the incidence of DRE remains high, the TASK1 workgroup on DRE of the ILAE/American Epilepsy Society (AES) Joint Translational Task Force discussed the heterogeneity and complexity of its presentation and mechanisms, the confounders in drawing mechanistic insights when testing treatment responses, and barriers in modeling DRE across the lifespan and translating across species. We propose that it is necessary to revisit the current definition of DRE, in order to transform the preclinical and clinical research of mechanisms and biomarkers, to identify novel, effective, precise, pharmacologic treatments, allowing for earlier recognition of drug resistance and individualized therapies.
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Affiliation(s)
- Stéphane Auvin
- Institut Universitaire de France, Paris, France
- Paediatric Neurology, Assistance Publique - Hôpitaux de Paris, EpiCARE ERN Member, Robert-Debré Hospital, Paris, France
- University Paris-Cité, Paris, France
| | - Aristea S Galanopoulou
- Saul R. Korey Department of Neurology, Isabelle Rapin Division of Child Neurology, Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, and Montefiore/Einstein Epilepsy Center, Bronx, New York, USA
| | - Solomon L Moshé
- Saul R. Korey Department of Neurology, Isabelle Rapin Division of Child Neurology, Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, and Montefiore/Einstein Epilepsy Center, Bronx, New York, USA
- Department of Pediatrics, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Heidrun Potschka
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig-Maximilians-University (LMU), Munich, Germany
| | - Luisa Rocha
- Pharmacobiology Department, Center for Research and Advanced Studies (CINVESTAV), Mexico City, Mexico
| | - Matthew C Walker
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK
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Dini G, Di Cara G, Ferrara P, Striano P, Verrotti A. Reintroducing Fenfluramine as a Treatment for Seizures: Current Knowledge, Recommendations and Gaps in Understanding. Neuropsychiatr Dis Treat 2023; 19:2013-2025. [PMID: 37790801 PMCID: PMC10543412 DOI: 10.2147/ndt.s417676] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Accepted: 09/19/2023] [Indexed: 10/05/2023] Open
Abstract
Despite the introduction of new anti-seizure medications in recent years, approximately one-third of the epileptic population continues to experience seizures. Recently, the anti-obesity medication fenfluramine (FFA) has been successfully repurposed, and it has received approval from various regulatory agencies for the treatment of seizures associated with Dravet syndrome and Lennox-Gastaut syndrome. The potential antiseizure effects of FFA were initially observed in patients with photosensitive epilepsy in the 1980s but it was not rigorously explored as a treatment option until 30 years later. This narrative review aims to provide an overview of the historical progression of FFA's use, starting from initial clinical observations to preclinical studies and, ultimately, successful clinical trials in the field of epilepsy.
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Affiliation(s)
- Gianluca Dini
- Department of Pediatrics, University of Perugia, Perugia, Italy
| | | | - Pietro Ferrara
- Department of Pediatrics, Campus Bio-Medico University, Rome, Italy
| | - Pasquale Striano
- Pediatric Neurology and Muscular Diseases Unit, IRCCS Istituto “G. Gaslini”, Genoa, Italy
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Bartoszek A, Trzpil A, Kozub A, Fornal E. Optimization of the Zebrafish Larvae Pentylenetetrazol-Induced Seizure Model for the Study of Caffeine and Topiramate Interactions. Int J Mol Sci 2023; 24:12723. [PMID: 37628904 PMCID: PMC10454524 DOI: 10.3390/ijms241612723] [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: 07/27/2023] [Revised: 08/07/2023] [Accepted: 08/10/2023] [Indexed: 08/27/2023] Open
Abstract
Epilepsy is a common neurological disorder characterized by seizures that cause neurobiological and behavioral impairment. Caffeine (CAF), which is the most widely consumed stimulant in the world, is reported to influence epileptic seizures and antiepileptic drugs, especially topiramate (TPM). The aim of the study was to optimize the zebrafish larvae pentylenetetrazol-induced seizure model for the study of CAF and TPM interactions, which include the determination of dose space, and the delivery of an analytical method for monitoring CAF, TPM, and CAF metabolite paraxanthine (PAR) in Zebrafish larvae. Methods: The zebrafish larvae, 4 days post-fertilization, were incubated for 18 h with CAF, TPM, or CAF + TPM, with subsequent locomotor activity assessment. Seizures were evoked by adding PTZ solution to obtain a final concentration of 20 mM. Subsequently, the liquid chromatography-mass spectrometry (LC-MS/MS) analytical method was used to simultaneously assess the levels of both CAF and TPM in the larvae. CAF (50 mg/L) and TPM (75 μM) given separately decreased the average larvae locomotor activity compared to the PTZ group but, however, were not able to lower it to the control level. Co-administration of 25 mg/L CAF and 50 μM TPM suppressed the activity to the same level. Adding 25 μM TPM to 50 mg/L CAF decrease the measured CAF level in the larvae. Until proven otherwise, CAF consumption should be regarded as a potential determinant in the modulation of TPM's efficacy in the management of epileptic seizures. The optimized model will contribute to the standardization of studying CAF and TPM interactions and building the understanding of the molecular bases of the interaction.
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Affiliation(s)
- Adrian Bartoszek
- Department of Bioanalytics, Medical University of Lublin, ul. Jaczewskiego 8b, 20-090 Lublin, Poland (E.F.)
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Del Pozo A, Knox KM, Lehmann L, Davidson S, Rho S, Jayadev S, Barker-Haliski M. Chronic evoked seizures in young pre-symptomatic APP/PS1 mice induce serotonin changes and accelerate onset on Alzheimer's disease-related neurpathology. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.05.522897. [PMID: 36711965 PMCID: PMC9881977 DOI: 10.1101/2023.01.05.522897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
OBJECTIVE People with early-onset Alzheimer's disease (AD) are at elevated seizure risk. Further, chronic seizures in pre-symptomatic stages may disrupt serotonin pathway-related protein expression, precipitating the onset of AD-related pathology and burden of neuropsychiatric comorbidities. METHODS 2-3-month-old APP/PS1, PSEN2-N141I, and transgenic control mice were sham or corneal kindled for 2 weeks to model chronic seizures. Seizure-induced changes in glia, serotonin pathway proteins, and amyloid beta; levels in hippocampus and prefrontal cortex were quantified. RESULTS APP/PS1 mice experienced worsened mortality versus kindled Tg- controls. APP/PS1 females were also more susceptible to chronic kindled seizures. These changes correlated with a marked downregulation of hippocampal tryptophan hydroxylase 2 and monoamine oxidase A protein expression compared to controls; these changes were not detected in PSEN2-N141I mice. Kindled APP/PS1 mice exhibited amyloid beta; overexpression and glial overactivity without plaque deposition. PSEN2 protein expression was AD model-dependent. SIGNIFICANCE Seizures evoked in pre-symptomatic APP/PS1 mice promotes premature mortality in the absence of pathological amyloid deposition. Disruptions in serotonin pathway metabolism are associated with increased glial reactivity and PSEN2 downregulation without amyloid beta; deposition. This study provides the first direct evidence that seizures occurring prior to amyloid beta, plaque accumulation worsen disease burden in an AD genotype-specific manner.
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Skiba A, Pellegata D, Morozova V, Kozioł E, Budzyńska B, Lee SMY, Gertsch J, Skalicka-Woźniak K. Pharmacometabolic Effects of Pteryxin and Valproate on Pentylenetetrazole-Induced Seizures in Zebrafish Reveal Vagus Nerve Stimulation. Cells 2023; 12:1540. [PMID: 37296660 PMCID: PMC10252891 DOI: 10.3390/cells12111540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 05/31/2023] [Accepted: 06/01/2023] [Indexed: 06/12/2023] Open
Abstract
Zebrafish (Danio rerio) assays provide a versatile pharmacological platform to test compounds on a wide range of behaviors in a whole organism. A major challenge lies in the lack of knowledge about the bioavailability and pharmacodynamic effects of bioactive compounds in this model organism. Here, we employed a combined methodology of LC-ESI-MS/MS analytics and targeted metabolomics with behavioral experiments to evaluate the anticonvulsant and potentially toxic effects of the angular dihydropyranocoumarin pteryxin (PTX) in comparison to the antiepileptic drug sodium valproate (VPN) in zebrafish larvae. PTX occurs in different Apiaceae plants traditionally used in Europe to treat epilepsy but has not been investigated so far. To compare potency and efficacy, the uptake of PTX and VPN into zebrafish larvae was quantified as larvae whole-body concentrations together with amino acids and neurotransmitters as proxy pharmacodynamic readout. The convulsant agent pentylenetetrazole (PTZ) acutely reduced the levels of most metabolites, including acetylcholine and serotonin. Conversely, PTX strongly reduced neutral essential amino acids in a LAT1 (SLCA5)-independent manner, but, similarly to VPN specifically increased the levels of serotonin, acetylcholine, and choline, but also ethanolamine. PTX dose and time-dependent manner inhibited PTZ-induced seizure-like movements resulting in a ~70% efficacy after 1 h at 20 µM (the equivalent of 4.28 ± 0.28 µg/g in larvae whole-body). VPN treated for 1 h with 5 mM (the equivalent of 18.17 ± 0.40 µg/g in larvae whole-body) showed a ~80% efficacy. Unexpectedly, PTX (1-20 µM) showed significantly higher bioavailability than VPN (0.1-5 mM) in immersed zebrafish larvae, possibly because VPN in the medium dissociated partially to the readily bioavailable valproic acid. The anticonvulsive effect of PTX was confirmed by local field potential (LFP) recordings. Noteworthy, both substances specifically increased and restored whole-body acetylcholine, choline, and serotonin levels in control and PTZ-treated zebrafish larvae, indicative of vagus nerve stimulation (VNS), which is an adjunctive therapeutic strategy to treat refractory epilepsy in humans. Our study demonstrates the utility of targeted metabolomics in zebrafish assays and shows that VPN and PTX pharmacologically act on the autonomous nervous system by activating parasympathetic neurotransmitters.
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Affiliation(s)
- Adrianna Skiba
- Department of Chemistry of Natural Products, Medical University of Lublin, 20-093 Lublin, Poland
| | - Daniele Pellegata
- Institute of Biochemistry and Molecular Medicine, University of Bern, 3012 Bern, Switzerland (V.M.)
| | - Veronika Morozova
- Institute of Biochemistry and Molecular Medicine, University of Bern, 3012 Bern, Switzerland (V.M.)
| | - Ewelina Kozioł
- Department of Chemistry of Natural Products, Medical University of Lublin, 20-093 Lublin, Poland
| | - Barbara Budzyńska
- Independent Laboratory of Behavioral Studies, Medical University of Lublin, 20-093 Lublin, Poland;
| | - Simon Ming-Yuen Lee
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao 519020, China;
| | - Jürg Gertsch
- Institute of Biochemistry and Molecular Medicine, University of Bern, 3012 Bern, Switzerland (V.M.)
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D'Amora M, Galgani A, Marchese M, Tantussi F, Faraguna U, De Angelis F, Giorgi FS. Zebrafish as an Innovative Tool for Epilepsy Modeling: State of the Art and Potential Future Directions. Int J Mol Sci 2023; 24:ijms24097702. [PMID: 37175408 PMCID: PMC10177843 DOI: 10.3390/ijms24097702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 04/20/2023] [Accepted: 04/20/2023] [Indexed: 05/15/2023] Open
Abstract
This article discusses the potential of Zebrafish (ZF) (Danio Rerio), as a model for epilepsy research. Epilepsy is a neurological disorder affecting both children and adults, and many aspects of this disease are still poorly understood. In vivo and in vitro models derived from rodents are the most widely used for studying both epilepsy pathophysiology and novel drug treatments. However, researchers have recently obtained several valuable insights into these two fields of investigation by studying ZF. Despite the relatively simple brain structure of these animals, researchers can collect large amounts of data in a much shorter period and at lower costs compared to classical rodent models. This is particularly useful when a large number of candidate antiseizure drugs need to be screened, and ethical issues are minimized. In ZF, seizures have been induced through a variety of chemoconvulsants, primarily pentylenetetrazol (PTZ), kainic acid (KA), and pilocarpine. Furthermore, ZF can be easily genetically modified to test specific aspects of monogenic forms of human epilepsy, as well as to discover potential convulsive phenotypes in monogenic mutants. The article reports on the state-of-the-art and potential new fields of application of ZF research, including its potential role in revealing epileptogenic mechanisms, rather than merely assessing iatrogenic acute seizure modulation.
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Affiliation(s)
- Marta D'Amora
- Istituto Italiano di Tecnologia, 16163 Genova, Italy
- Department of Biology, University of Pisa, 56125 Pisa, Italy
| | - Alessandro Galgani
- Department of Translational Research and of New Surgical and Medical Technologies, University of Pisa, 56126 Pisa, Italy
| | - Maria Marchese
- Molecular Medicine and Neurobiology-ZebraLab, IRCCS Fondazione Stella Maris, 56128 Pisa, Italy
| | | | - Ugo Faraguna
- Department of Translational Research and of New Surgical and Medical Technologies, University of Pisa, 56126 Pisa, Italy
- Department of Developmental Neuroscience, IRCCS Fondazione Stella Maris, 56128 Pisa, Italy
| | | | - Filippo Sean Giorgi
- Department of Translational Research and of New Surgical and Medical Technologies, University of Pisa, 56126 Pisa, Italy
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Gao C, Pielas M, Jiao F, Mei D, Wang X, Kotulska K, Jozwiak S. Epilepsy in Dravet Syndrome—Current and Future Therapeutic Opportunities. J Clin Med 2023; 12:jcm12072532. [PMID: 37048615 PMCID: PMC10094968 DOI: 10.3390/jcm12072532] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 03/17/2023] [Accepted: 03/23/2023] [Indexed: 03/30/2023] Open
Abstract
Dravet Syndrome (DS) is a developmental epileptic encephalopathy characterized by drug-resistant seizures and other clinical features, including intellectual disability and behavioral, sleep, and gait problems. The pathogenesis is strongly connected to voltage-gated sodium channel dysfunction. The current consensus of seizure management in DS consists of a combination of conventional and recently approved drugs such as stiripentol, cannabidiol, and fenfluramine. Despite promising results in randomized clinical trials and extension studies, the prognosis of the developmental outcomes of patients with DS remains unfavorable. The article summarizes recent changes in the therapeutic approach to DS and discusses ongoing clinical research directions. Serotonergic agents under investigation show promising results and may replace less DS-specific medicines. The use of antisense nucleotides and gene therapy is focused not only on symptom relief but primarily addresses the underlying cause of the syndrome. Novel compounds, after expected safe and successful implementation in clinical practice, will open a new era for patients with DS. The main goal of causative treatment is to modify the natural course of the disease and provide the best neurodevelopmental outcome with minimum neurological deficit.
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Abstract
The ability to develop effective new treatments for epilepsy may depend on improved understanding of seizure pathophysiology, about which many questions remain. Dynamic fluorescence imaging of activity at single-neuron resolution with fluorescent indicators in experimental model systems in vivo has revolutionized basic neuroscience and has the potential to do so for epilepsy research as well. Here, we review salient issues as they pertain to experimental imaging in basic epilepsy research, including commonly used imaging technologies, data processing and analysis, interpretation of results, and selected examples of how imaging-based approaches have revealed new insight into mechanisms of seizures and epilepsy.
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Affiliation(s)
- Patrick N. Lawlor
- Division of Neurology, Department of Pediatrics, The Children’s Hospital of Philadelphia, Philadelphia, PA
| | - Ethan M. Goldberg
- Division of Neurology, Department of Pediatrics, The Children’s Hospital of Philadelphia, Philadelphia, PA
- The Epilepsy Neurogenetics Initiative, The Children’s Hospital of Philadelphia, Philadelphia
- Department of Neurology, The University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Department of Neuroscience, The University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
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13
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Fenfluramine for the Treatment of Dravet Syndrome and Lennox Gastaut Syndrome: A Review. Curr Treat Options Neurol 2022. [DOI: 10.1007/s11940-022-00741-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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14
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Samanta D. Fenfluramine: A Review of Pharmacology, Clinical Efficacy, and Safety in Epilepsy. CHILDREN 2022; 9:children9081159. [PMID: 36010049 PMCID: PMC9406381 DOI: 10.3390/children9081159] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 07/30/2022] [Accepted: 08/01/2022] [Indexed: 11/29/2022]
Abstract
Despite the availability of more than 30 antiseizure medications (ASMs), the proportion of patients who remain refractory to ASMs remains static. Refractory seizures are almost universal in patients with epileptic encephalopathies. Since many of these patients are not candidates for curative surgery, there is always a need for newer ASMs with better efficacy and safety profile. Recently, the anti-obesity medication fenfluramine (FFA) has been successfully repurposed, and various regulatory agencies approved it for seizures associated with Dravet and Lennox–Gastaut syndromes. However, there is a limited in-depth critical review of FFA to facilitate its optimal use in a clinical context. This narrative review discusses and summarizes the antiseizure mechanism of action of FFA, clinical pharmacology, and clinical studies related to epilepsy, focusing on efficacy and adverse effects.
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Affiliation(s)
- Debopam Samanta
- Child Neurology Section, Department of Pediatrics, University of Arkansas for Medical Sciences, 1 Children's Way, Little Rock, AR 72202, USA
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15
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del Pozo A, Lehmann L, Knox KM, Barker-Haliski M. Can Old Animals Reveal New Targets? The Aging and Degenerating Brain as a New Precision Medicine Opportunity for Epilepsy. Front Neurol 2022; 13:833624. [PMID: 35572927 PMCID: PMC9096090 DOI: 10.3389/fneur.2022.833624] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Accepted: 04/07/2022] [Indexed: 02/02/2023] Open
Abstract
Older people represent the fastest growing group with epilepsy diagnosis. For example, cerebrovascular disease may underlie roughly 30-50% of epilepsy in older adults and seizures are also an underrecognized comorbidity of Alzheimer's disease (AD). As a result, up to 10% of nursing home residents may take antiseizure medicines (ASMs). Despite the greater incidence of epilepsy in older individuals and increased risk of comorbid seizures in people with AD, aged animals with seizures are strikingly underrepresented in epilepsy drug discovery practice. Increased integration of aged animals into preclinical epilepsy drug discovery could better inform the potential tolerability and pharmacokinetic interactions in aged individuals as the global population becomes increasingly older. Quite simply, the ASMs on the market today were brought forth based on efficacy in young adult, neurologically intact rodents; preclinical information concerning the efficacy and safety of promising ASMs is not routinely evaluated in aged animals. Integrating aged animals more often into basic epilepsy research may also uncover novel treatments for hyperexcitability. For example, cannabidiol and fenfluramine demonstrated clear efficacy in syndrome-specific pediatric models that led to a paradigm shift in the perceived value of pediatric models for ASM discovery practice; aged rodents with seizures or rodents with aging-related neuropathology represent an untapped resource that could similarly change epilepsy drug discovery. This review, therefore, summarizes how aged rodent models have thus far been used for epilepsy research, what studies have been conducted to assess ASM efficacy in aged rodent seizure and epilepsy models, and lastly to identify remaining gaps to engage aging-related neurological disease models for ASM discovery, which may simultaneously reveal novel mechanisms associated with epilepsy.
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Affiliation(s)
| | | | | | - Melissa Barker-Haliski
- Department of Pharmacy, School of Pharmacy, University of Washington, Seattle, WA, United States
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16
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Bialer M, Perucca E. Lorcaserin for Dravet Syndrome: A Potential Advance Over Fenfluramine? CNS Drugs 2022; 36:113-122. [PMID: 35094259 DOI: 10.1007/s40263-022-00896-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/09/2022] [Indexed: 12/12/2022]
Abstract
Lorcaserin, a selective serotonin 5-HT2C receptor agonist, was developed as an appetite suppressant with the rationale of minimizing the risk of cardiovascular toxicity associated with non-selective serotoninergic agents such as fenfluramine. Eight years after FDA approval, however, it was withdrawn from the market, when a large safety study suggested a potential cancer risk. Following in the fenfluramine footsteps and utilizing the repurposing approach coupled with the regulatory orphan drug designation, lorcaserin is currently in clinical development for the treatment of epilepsy. This potential novel indication builds on the evidence that 5-HT2C receptor stimulation can protect against seizures, and accounts at least in part for fenfluramine's antiseizure effects in Dravet syndrome models. In animal models, lorcaserin shows a narrower range of antiseizure activity than fenfluramine. In particular, lorcaserin is inactive in classical acute seizure tests such as maximal electroshock and subcutaneous pentylenetetrazole in mice and rats, and the 6-Hz stimulation model in mice. However, it is active in the GAERS absence seizure model, and in mutant zebrafish models of Dravet syndrome. Preliminary uncontrolled studies in patients with Dravet syndrome have yielded promising results, and a phase III, double-blind, placebo-controlled, parallel group trial is currently ongoing to assess its efficacy and safety in children and adults with Dravet syndrome.
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Affiliation(s)
- Meir Bialer
- Institute of Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel. .,David R. Bloom Center for Pharmacy, The Hebrew University of Jerusalem, Jerusalem, Israel.
| | - Emilio Perucca
- Department of Medicine, Austin Health, University of Melbourne, Melbourne, VIC, Australia.,Department of Neuroscience, Monash University, Melbourne, VIC, Australia
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17
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Genetic and Functional Differences between Duplicated Zebrafish Genes for Human SCN1A. Cells 2022; 11:cells11030454. [PMID: 35159264 PMCID: PMC8834172 DOI: 10.3390/cells11030454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 01/21/2022] [Accepted: 01/26/2022] [Indexed: 02/04/2023] Open
Abstract
There are currently seven different zebrafish strains that model Dravet Syndrome, a severe childhood form of epilepsy. These models are based on a set of duplicated genes, scn1laa and scn1lab, which are the homologs for human SCN1A. Disrupting one of the genes would mimic a heterozygous disease state in humans, as the paralog gene is still present. While this ‘disease-state model’ is widely accepted, there is also evidence that the function of these genes might not be completely the same. By analyzing the functional domains, we discovered several hotspots in the protein that are not conserved, indicating a functional difference. Based on this, we generated scn1Laa knockout zebrafish and compared their phenotype to scn1lab knockouts. The genetic and functional differences we discovered can have implications for the use of zebrafish as a model for Dravet Syndrome.
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Crouzier L, Richard EM, Sourbron J, Lagae L, Maurice T, Delprat B. Use of Zebrafish Models to Boost Research in Rare Genetic Diseases. Int J Mol Sci 2021; 22:13356. [PMID: 34948153 PMCID: PMC8706563 DOI: 10.3390/ijms222413356] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 12/09/2021] [Accepted: 12/10/2021] [Indexed: 02/06/2023] Open
Abstract
Rare genetic diseases are a group of pathologies with often unmet clinical needs. Even if rare by a single genetic disease (from 1/2000 to 1/more than 1,000,000), the total number of patients concerned account for approximatively 400 million peoples worldwide. Finding treatments remains challenging due to the complexity of these diseases, the small number of patients and the challenge in conducting clinical trials. Therefore, innovative preclinical research strategies are required. The zebrafish has emerged as a powerful animal model for investigating rare diseases. Zebrafish combines conserved vertebrate characteristics with high rate of breeding, limited housing requirements and low costs. More than 84% of human genes responsible for diseases present an orthologue, suggesting that the majority of genetic diseases could be modelized in zebrafish. In this review, we emphasize the unique advantages of zebrafish models over other in vivo models, particularly underlining the high throughput phenotypic capacity for therapeutic screening. We briefly introduce how the generation of zebrafish transgenic lines by gene-modulating technologies can be used to model rare genetic diseases. Then, we describe how zebrafish could be phenotyped using state-of-the-art technologies. Two prototypic examples of rare diseases illustrate how zebrafish models could play a critical role in deciphering the underlying mechanisms of rare genetic diseases and their use to identify innovative therapeutic solutions.
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Affiliation(s)
- Lucie Crouzier
- MMDN, University of Montpellier, EPHE, INSERM, 34095 Montpellier, France; (L.C.); (E.M.R.); (T.M.)
| | - Elodie M. Richard
- MMDN, University of Montpellier, EPHE, INSERM, 34095 Montpellier, France; (L.C.); (E.M.R.); (T.M.)
| | - Jo Sourbron
- Department of Development and Regeneration, Section Pediatric Neurology, University Hospital KU Leuven, 3000 Leuven, Belgium; (J.S.); (L.L.)
| | - Lieven Lagae
- Department of Development and Regeneration, Section Pediatric Neurology, University Hospital KU Leuven, 3000 Leuven, Belgium; (J.S.); (L.L.)
| | - Tangui Maurice
- MMDN, University of Montpellier, EPHE, INSERM, 34095 Montpellier, France; (L.C.); (E.M.R.); (T.M.)
| | - Benjamin Delprat
- MMDN, University of Montpellier, EPHE, INSERM, 34095 Montpellier, France; (L.C.); (E.M.R.); (T.M.)
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19
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Hotz AL, Jamali A, Rieser NN, Niklaus S, Aydin E, Myren‐Svelstad S, Lalla L, Jurisch‐Yaksi N, Yaksi E, Neuhauss SCF. Loss of glutamate transporter eaat2a leads to aberrant neuronal excitability, recurrent epileptic seizures, and basal hypoactivity. Glia 2021; 70:196-214. [PMID: 34716961 PMCID: PMC9297858 DOI: 10.1002/glia.24106] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 10/05/2021] [Accepted: 10/06/2021] [Indexed: 11/13/2022]
Abstract
Astroglial excitatory amino acid transporter 2 (EAAT2, GLT‐1, and SLC1A2) regulates the duration and extent of neuronal excitation by removing glutamate from the synaptic cleft. Hence, an impairment in EAAT2 function could lead to an imbalanced brain network excitability. Here, we investigated the functional alterations of neuronal and astroglial networks associated with the loss of function in the astroglia predominant eaat2a gene in zebrafish. We observed that eaat2a−/− mutant zebrafish larvae display recurrent spontaneous and light‐induced seizures in neurons and astroglia, which coincide with an abrupt increase in extracellular glutamate levels. In stark contrast to this hyperexcitability, basal neuronal and astroglial activity was surprisingly reduced in eaat2a−/− mutant animals, which manifested in decreased overall locomotion. Our results reveal an essential and mechanistic contribution of EAAT2a in balancing brain excitability, and its direct link to epileptic seizures.
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Affiliation(s)
- Adriana L. Hotz
- Department of Molecular Life SciencesUniversity of ZurichZurichSwitzerland
- Life Science Zürich Graduate School ‐ NeuroscienceUniversity of Zurich and ETH ZurichZurichSwitzerland
| | - Ahmed Jamali
- Kavli Institute for Systems Neuroscience and Centre for Neural ComputationFaculty of Medicine and Health Sciences, Norwegian University of Science and TechnologyTrondheimNorway
| | - Nicolas N. Rieser
- Department of Molecular Life SciencesUniversity of ZurichZurichSwitzerland
- Life Science Zürich Graduate School ‐ NeuroscienceUniversity of Zurich and ETH ZurichZurichSwitzerland
| | - Stephanie Niklaus
- Department of Molecular Life SciencesUniversity of ZurichZurichSwitzerland
- Present address:
EraCal TherapeuticsSchlierenSwitzerland
| | - Ecem Aydin
- Kavli Institute for Systems Neuroscience and Centre for Neural ComputationFaculty of Medicine and Health Sciences, Norwegian University of Science and TechnologyTrondheimNorway
| | - Sverre Myren‐Svelstad
- Kavli Institute for Systems Neuroscience and Centre for Neural ComputationFaculty of Medicine and Health Sciences, Norwegian University of Science and TechnologyTrondheimNorway
- Department of Neurology and Clinical NeurophysiologySt. Olav's University HospitalTrondheimNorway
- Department of Neuromedicine and Movement Science, Faculty of Medicine and Health SciencesNorwegian University of Science and TechnologyTrondheimNorway
| | - Laetitia Lalla
- Kavli Institute for Systems Neuroscience and Centre for Neural ComputationFaculty of Medicine and Health Sciences, Norwegian University of Science and TechnologyTrondheimNorway
| | - Nathalie Jurisch‐Yaksi
- Kavli Institute for Systems Neuroscience and Centre for Neural ComputationFaculty of Medicine and Health Sciences, Norwegian University of Science and TechnologyTrondheimNorway
- Department of Neurology and Clinical NeurophysiologySt. Olav's University HospitalTrondheimNorway
- Department of Clinical and Molecular Medicine, Faculty of Medicine and Health SciencesNorwegian University of Science and TechnologyTrondheimNorway
| | - Emre Yaksi
- Kavli Institute for Systems Neuroscience and Centre for Neural ComputationFaculty of Medicine and Health Sciences, Norwegian University of Science and TechnologyTrondheimNorway
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20
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Gogou M, Cross JH. Fenfluramine as antiseizure medication for epilepsy. Dev Med Child Neurol 2021; 63:899-907. [PMID: 33565102 DOI: 10.1111/dmcn.14822] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/05/2021] [Indexed: 12/11/2022]
Abstract
Fenfluramine hydrochloride has classically been described as acting pharmacologically through a serotonergic mechanism. Therefore, it was initially used as an anorectic drug, given that impaired serotonin homeostasis may be associated with increased food intake. Although positive results were documented, cardiovascular concerns resulted in its temporary withdrawal. Nevertheless, a novel role in patients with epilepsy was later suggested by isolated clinical observations. The wide application of genetic testing allowed the classification (predominantly as Dravet syndrome) of patients in whom benefit was seen, while with the development of zebrafish models, its antiepileptic properties were confirmed at a molecular level. Data from randomized clinical trials have shown a beneficial effect of fenfluramine, as an adjunct therapy, on seizure control for children with Dravet syndrome, though there is still uncertainty about the impact on neurodevelopment in these patients. No signs of heart valve disease have been documented to date. Long-term and appropriately designed clinical studies will verify whether fenfluramine is a therapeutic agent of high importance, living up to the promise shown so far. What this paper adds Fenfluramine is a very promising repurposed therapy specifically for seizures in Dravet syndrome. The long-term effect of fenfluramine on neurodevelopmental prognosis requires further investigation.
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Affiliation(s)
- Maria Gogou
- Department of Neurology, Great Ormond Street Hospital for Children NHS Trust, London, UK
| | - J Helen Cross
- Department of Neurology, Great Ormond Street Hospital for Children NHS Trust, London, UK.,Developmental Neurosciences, University College London NIHR BRC Great Ormond Street Institute of Child Health, London, UK
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21
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Weuring WJ, Dilevska I, Hoekman J, van de Vondervoort J, Koetsier M, van 't Slot RH, Braun KPJ, Koeleman BPC. CRISPRa-Mediated Upregulation of scn1laa During Early Development Causes Epileptiform Activity and dCas9-Associated Toxicity. CRISPR J 2021; 4:575-582. [PMID: 34406040 DOI: 10.1089/crispr.2021.0013] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
Dravet syndrome (DS) is a monogenic epileptic encephalopathy caused by loss-of-function mutations in the voltage-gated sodium channel (VGSC) gene SCN1A. DS has an age of onset within the first year of life and severe disease prognosis. In the past years, it has been shown that upregulation of endogenous SCN1A can be beneficial in animal models for DS, but a complete rescue was not observed. We hypothesized that upregulation during early development that precedes onset of first symptoms might improve disease outcome. To test this hypothesis, we first evaluated the CRISPR activating method for early upregulation of voltage gated sodium channels during early development. We injected CRISPRa components, which target the proximal or distal promoter region of the VGSC gene scn1Laa in the yolk of one-cell stage zebrafish embryos. The effect of both dCas9-VPR and dCas9-VP64 was evaluated. Both CRISPRa fusions showed toxicity in the majority of embryos, with or without guide RNAs. The few embryos that survived developed normally, and dCas9-VPR induces an upregulation of scn1Laa mRNA until 24 hours after fertilization. At 5 days post fertilization, CRISPRa-injected embryos showed an epileptic phenotype, including locomotor burst movements, hyperactivity, and epileptiform activity originating from the brain. In addition to previously published scn1Laa and scn1Lab loss-of-function models, we conclude that gain of scn1Laa function can have an equally severe phenotype. Upregulation of scn1Laa in the current zebrafish model for DS, scn1Lab-KO, aggravated the disease phenotype, highlighting that early-stage upregulation using CRISPRa can lead to both toxicity and a worsening of the disease phenotype.
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Affiliation(s)
- Wout J Weuring
- Department of Genetics, University Medical Center Utrecht Brain Center, University Medical Centre Utrecht, Utrecht, The Netherlands; and University Medical Centre Utrecht, Utrecht, The Netherlands; member of the ERN EpiCARE
| | - Ivana Dilevska
- Department of Genetics, University Medical Center Utrecht Brain Center, University Medical Centre Utrecht, Utrecht, The Netherlands; and University Medical Centre Utrecht, Utrecht, The Netherlands; member of the ERN EpiCARE
| | - Jos Hoekman
- Department of Genetics, University Medical Center Utrecht Brain Center, University Medical Centre Utrecht, Utrecht, The Netherlands; and University Medical Centre Utrecht, Utrecht, The Netherlands; member of the ERN EpiCARE
| | - Joep van de Vondervoort
- Department of Genetics, University Medical Center Utrecht Brain Center, University Medical Centre Utrecht, Utrecht, The Netherlands; and University Medical Centre Utrecht, Utrecht, The Netherlands; member of the ERN EpiCARE
| | - Martijn Koetsier
- Department of Genetics, University Medical Center Utrecht Brain Center, University Medical Centre Utrecht, Utrecht, The Netherlands; and University Medical Centre Utrecht, Utrecht, The Netherlands; member of the ERN EpiCARE
| | - Ruben H van 't Slot
- Department of Genetics, University Medical Center Utrecht Brain Center, University Medical Centre Utrecht, Utrecht, The Netherlands; and University Medical Centre Utrecht, Utrecht, The Netherlands; member of the ERN EpiCARE
| | - Kees P J Braun
- Department of Neurology and Neurosurgery, University Medical Centre Utrecht, Utrecht, The Netherlands; member of the ERN EpiCARE
| | - Bobby P C Koeleman
- Department of Genetics, University Medical Center Utrecht Brain Center, University Medical Centre Utrecht, Utrecht, The Netherlands; and University Medical Centre Utrecht, Utrecht, The Netherlands; member of the ERN EpiCARE
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22
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Galanopoulou AS, Löscher W, Lubbers L, O’Brien TJ, Staley K, Vezzani A, D’Ambrosio R, White HS, Sontheimer H, Wolf JA, Twyman R, Whittemore V, Wilcox KS, Klein B. Antiepileptogenesis and disease modification: Progress, challenges, and the path forward-Report of the Preclinical Working Group of the 2018 NINDS-sponsored antiepileptogenesis and disease modification workshop. Epilepsia Open 2021; 6:276-296. [PMID: 34033232 PMCID: PMC8166793 DOI: 10.1002/epi4.12490] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 04/04/2021] [Accepted: 04/12/2021] [Indexed: 12/12/2022] Open
Abstract
Epilepsy is one of the most common chronic brain diseases and is often associated with cognitive, behavioral, or other medical conditions. The need for therapies that would prevent, ameliorate, or cure epilepsy and the attendant comorbidities is a priority for both epilepsy research and public health. In 2018, the National Institute of Neurological Disease and Stroke (NINDS) convened a workshop titled "Accelerating the Development of Therapies for Antiepileptogenesis and Disease Modification" that brought together preclinical and clinical investigators and industry and regulatory bodies' representatives to discuss and propose a roadmap to accelerate the development of antiepileptogenic (AEG) and disease-modifying (DM) new therapies. This report provides a summary of the discussions and proposals of the Preclinical Science working group. Highlights of the progress of collaborative preclinical research projects on AEG/DM of ongoing research initiatives aiming to improve infrastructure and translation to clinical trials are presented. Opportunities and challenges of preclinical epilepsy research, vis-à-vis clinical research, were extensively discussed, as they pertain to modeling of specific epilepsy types across etiologies and ages, the utilization of preclinical models in AG/DM studies, and the strategies and study designs, as well as on matters pertaining to transparency, data sharing, and reporting research findings. A set of suggestions on research initiatives, infrastructure, workshops, advocacy, and opportunities for expanding the borders of epilepsy research were discussed and proposed as useful initiatives that could help create a roadmap to accelerate and optimize preclinical translational AEG/DM epilepsy research.
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Affiliation(s)
- Aristea S. Galanopoulou
- Saul R. Korey Department of NeurologyDominick P. Purpura Department of NeuroscienceIsabelle Rapin Division of Child NeurologyAlbert Einstein College of MedicineBronxNYUSA
| | - Wolfgang Löscher
- Department of Pharmacology, Toxicology, and PharmacyUniversity of Veterinary Medicine HannoverHannoverGermany
| | | | - Terence J. O’Brien
- Department of NeuroscienceCentral Clinical SchoolAlfred HealthMonash UniversityMelbourneVic.Australia
| | - Kevin Staley
- Department of NeurologyMassachusetts General HospitalBostonMAUSA
| | - Annamaria Vezzani
- Department of NeuroscienceIRCCS‐Mario Negri Institute for Pharmacological ResearchMilanoItaly
| | | | - H. Steve White
- Department of PharmacySchool of PharmacyUniversity of WashingtonSeattleWAUSA
| | | | - John A. Wolf
- Center for Brain Injury and RepairDepartment of NeurosurgeryUniversity of PennsylvaniaPhiladelphiaPAUSA
- Corporal Michael J. Crescenz Veterans Affairs Medical CenterPhiladelphiaPAUSA
| | | | - Vicky Whittemore
- National Institute of Neurological Disorders and StrokeNational Institutes of HealthBethesdaMDUSA
| | - Karen S. Wilcox
- Department of Pharmacology & ToxicologyUniversity of UtahSalt Lake CityUTUSA
| | - Brian Klein
- National Institute of Neurological Disorders and StrokeNational Institutes of HealthBethesdaMDUSA
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23
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Schoonjans AS, Ceulemans B. Dravet syndrome—toward an optimal and disease-specific treatment. ZEITSCHRIFT FÜR EPILEPTOLOGIE 2021. [DOI: 10.1007/s10309-021-00399-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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24
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Zebrafish Models of Autosomal Recessive Ataxias. Cells 2021; 10:cells10040836. [PMID: 33917666 PMCID: PMC8068028 DOI: 10.3390/cells10040836] [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: 03/09/2021] [Revised: 04/01/2021] [Accepted: 04/06/2021] [Indexed: 12/11/2022] Open
Abstract
Autosomal recessive ataxias are much less well studied than autosomal dominant ataxias and there are no clearly defined systems to classify them. Autosomal recessive ataxias, which are characterized by neuronal and multisystemic features, have significant overlapping symptoms with other complex multisystemic recessive disorders. The generation of animal models of neurodegenerative disorders increases our knowledge of their cellular and molecular mechanisms and helps in the search for new therapies. Among animal models, the zebrafish, which shares 70% of its genome with humans, offer the advantages of being small in size and demonstrating rapid development, making them optimal for high throughput drug and genetic screening. Furthermore, embryo and larval transparency allows to visualize cellular processes and central nervous system development in vivo. In this review, we discuss the contributions of zebrafish models to the study of autosomal recessive ataxias characteristic phenotypes, behavior, and gene function, in addition to commenting on possible treatments found in these models. Most of the zebrafish models generated to date recapitulate the main features of recessive ataxias.
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25
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Abstract
PURPOSE OF REVIEW The serotonergic system is implicated in multiple aspects of epilepsy, including seizure susceptibility, sudden unexpected death in epilepsy (SUDEP), and comorbid depression. Despite the complexity of serotonin's effects on various neuronal networks, ongoing research provides considerable insight into the role of serotonin in human epilepsy. This review explores the potential roles of serotonergic therapies to improve clinical outcomes in epilepsy. RECENT FINDINGS In recent decades, research has markedly increased our knowledge of the diverse effects of serotonin on brain function. Animal models of epilepsy have identified the influence of serotonin on seizure threshold in specific brain regions, serotoninergic augmentation's protective effects on terminal apnea and mortality in SUDEP, and mechanisms underlying behavioral improvement in some models of comorbid depression. Human clinical studies are largely consistent with animal data but the translation into definitive treatment decisions has moved less rapidly. SUMMARY Evidence for serotonergic therapy is promising for improvement in seizure control and prevention of SUDEP. For some epilepsies, such as Dravet syndrome, basic research on serotonin receptor agonists has translated into a positive clinical trial for fenfluramine. The cumulative results of safety and efficacy studies support the routine use of SSRIs for comorbid depression in epilepsy.
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Affiliation(s)
| | | | - Matthew S. Gentry
- Department of Molecular and Cellular Biochemistry, University of Kentucky
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26
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Schoonjans AS, Ceulemans B. A critical evaluation of fenfluramine hydrochloride for the treatment of Dravet syndrome. Expert Rev Neurother 2021; 22:351-364. [PMID: 33455486 DOI: 10.1080/14737175.2021.1877540] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Introduction: Dravet Syndrome (DS) is a severe developmental and epileptic encephalopathy. Fenfluramine recently demonstrated to be a highly efficacious and safe treatment option for DS patients. Fenfluramine has been recently approved by the FDA and EMA and is marketed as Fintepla®.Areas covered: DS and the need for additional anticonvulsive treatment options is discussed. The results of three placebo-controlled phase III studies (1 with and 2 without stiripentol) and 2 open label (extension) studies are reviewed. All studies demonstrate a consistent and impressive seizure reduction, confirming the results of two smaller investigator-initiated trials. The mechanism of action of fenfluramine is discussed. Finally, the place of fenfluramine in the future treatment of DS is outlined.Expert opinion: Fenfluramine has a potent anticonvulsive effect in DS. Although not yet fully elucidated, the anticonvulsive mechanism of fenfluramine seems to be mainly serotonergic. Fenfluramine is generally well tolerated. A dose reduction is necessary in combination with stiripentol. Considering new competitors, efficacy seems lower for cannabidiol and is comparable with stiripentol. Preclinical studies indicate a disease specific action and possible disease modification in DS. The latter would support the use of fenfluramine above its anticonvulsive effect and needs to be further elaborated.
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Affiliation(s)
- An-Sofie Schoonjans
- Department of Pediatrics and Pediatric Neurology, Antwerp University Hospital, Edegem, Belgium.,Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
| | - Berten Ceulemans
- Department of Pediatrics and Pediatric Neurology, Antwerp University Hospital, Edegem, Belgium.,Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
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27
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Quelle-Regaldie A, Sobrido-Cameán D, Barreiro-Iglesias A, Sobrido MJ, Sánchez L. Zebrafish Models of Autosomal Dominant Ataxias. Cells 2021; 10:421. [PMID: 33671313 PMCID: PMC7922657 DOI: 10.3390/cells10020421] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 02/11/2021] [Accepted: 02/12/2021] [Indexed: 12/13/2022] Open
Abstract
Hereditary dominant ataxias are a heterogeneous group of neurodegenerative conditions causing cerebellar dysfunction and characterized by progressive motor incoordination. Despite many efforts put into the study of these diseases, there are no effective treatments yet. Zebrafish models are widely used to characterize neuronal disorders due to its conserved vertebrate genetics that easily support genetic edition and their optic transparency that allows observing the intact CNS and its connections. In addition, its small size and external fertilization help to develop high throughput assays of candidate drugs. Here, we discuss the contributions of zebrafish models to the study of dominant ataxias defining phenotypes, genetic function, behavior and possible treatments. In addition, we review the zebrafish models created for X-linked repeat expansion diseases X-fragile/fragile-X tremor ataxia. Most of the models reviewed here presented neuronal damage and locomotor deficits. However, there is a generalized lack of zebrafish adult heterozygous models and there are no knock-in zebrafish models available for these diseases. The models created for dominant ataxias helped to elucidate gene function and mechanisms that cause neuronal damage. In the future, the application of new genetic edition techniques would help to develop more accurate zebrafish models of dominant ataxias.
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Affiliation(s)
- Ana Quelle-Regaldie
- Department of Zoology, Genetics and Physical Anthropology, Faculty of Veterinary Science, Universidade of Santiago de Compostela, 27002 Lugo, Spain; (A.Q.-R.); (L.S.)
| | - Daniel Sobrido-Cameán
- Department of Functional Biology, CIBUS, Faculty of Biology, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain;
| | - Antón Barreiro-Iglesias
- Department of Functional Biology, CIBUS, Faculty of Biology, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain;
| | - María Jesús Sobrido
- Instituto de Investigación Biomédica de A Coruña (INIBIC), Servicio Galego de Saúde, 15006 Coruña, Spain;
| | - Laura Sánchez
- Department of Zoology, Genetics and Physical Anthropology, Faculty of Veterinary Science, Universidade of Santiago de Compostela, 27002 Lugo, Spain; (A.Q.-R.); (L.S.)
- Preclinical Animal Models Group, Health Research Institute of Santiago de Compostela (IDIS), 15706 Santiago de Compostela, Spain
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28
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Prentzell MT, Rehbein U, Cadena Sandoval M, De Meulemeester AS, Baumeister R, Brohée L, Berdel B, Bockwoldt M, Carroll B, Chowdhury SR, von Deimling A, Demetriades C, Figlia G, de Araujo MEG, Heberle AM, Heiland I, Holzwarth B, Huber LA, Jaworski J, Kedra M, Kern K, Kopach A, Korolchuk VI, van 't Land-Kuper I, Macias M, Nellist M, Palm W, Pusch S, Ramos Pittol JM, Reil M, Reintjes A, Reuter F, Sampson JR, Scheldeman C, Siekierska A, Stefan E, Teleman AA, Thomas LE, Torres-Quesada O, Trump S, West HD, de Witte P, Woltering S, Yordanov TE, Zmorzynska J, Opitz CA, Thedieck K. G3BPs tether the TSC complex to lysosomes and suppress mTORC1 signaling. Cell 2021; 184:655-674.e27. [PMID: 33497611 PMCID: PMC7868890 DOI: 10.1016/j.cell.2020.12.024] [Citation(s) in RCA: 64] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 11/03/2020] [Accepted: 12/14/2020] [Indexed: 12/22/2022]
Abstract
Ras GTPase-activating protein-binding proteins 1 and 2 (G3BP1 and G3BP2, respectively) are widely recognized as core components of stress granules (SGs). We report that G3BPs reside at the cytoplasmic surface of lysosomes. They act in a non-redundant manner to anchor the tuberous sclerosis complex (TSC) protein complex to lysosomes and suppress activation of the metabolic master regulator mechanistic target of rapamycin complex 1 (mTORC1) by amino acids and insulin. Like the TSC complex, G3BP1 deficiency elicits phenotypes related to mTORC1 hyperactivity. In the context of tumors, low G3BP1 levels enhance mTORC1-driven breast cancer cell motility and correlate with adverse outcomes in patients. Furthermore, G3bp1 inhibition in zebrafish disturbs neuronal development and function, leading to white matter heterotopia and neuronal hyperactivity. Thus, G3BPs are not only core components of SGs but also a key element of lysosomal TSC-mTORC1 signaling.
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Affiliation(s)
- Mirja Tamara Prentzell
- Brain Cancer Metabolism Group, German Consortium of Translational Cancer Research (DKTK) & German Cancer Research Center (DKFZ), Heidelberg 69120, Germany; Department of Pediatrics, Section Systems Medicine of Metabolism and Signaling, University of Groningen, University Medical Center Groningen, Groningen 9700 RB, The Netherlands; Department of Bioinformatics and Molecular Genetics (Faculty of Biology), University of Freiburg, Freiburg 79104, Germany; Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, Freiburg 79104, Germany
| | - Ulrike Rehbein
- Department of Pediatrics, Section Systems Medicine of Metabolism and Signaling, University of Groningen, University Medical Center Groningen, Groningen 9700 RB, The Netherlands; Department for Neuroscience, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, Oldenburg 26129, Germany; Institute of Biochemistry and Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck 6020, Austria
| | - Marti Cadena Sandoval
- Department of Pediatrics, Section Systems Medicine of Metabolism and Signaling, University of Groningen, University Medical Center Groningen, Groningen 9700 RB, The Netherlands; Institute of Biochemistry and Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck 6020, Austria
| | - Ann-Sofie De Meulemeester
- Laboratory for Molecular Biodiscovery, Department of Pharmaceutical and Pharmacological Sciences, University of Leuven, Leuven BE-3000, Belgium
| | - Ralf Baumeister
- Department of Bioinformatics and Molecular Genetics (Faculty of Biology), University of Freiburg, Freiburg 79104, Germany; Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, Freiburg 79104, Germany; Signalling Research Centres BIOSS and CIBSS & ZBMZ Center for Biochemistry and Molecular Cell Research (Faculty of Medicine), University of Freiburg, Freiburg 79104, Germany
| | - Laura Brohée
- Cell Growth Control in Health and Age-Related Disease Group, Max Planck Institute for Biology of Ageing (MPI-AGE), Cologne 50931, Germany
| | - Bianca Berdel
- Brain Cancer Metabolism Group, German Consortium of Translational Cancer Research (DKTK) & German Cancer Research Center (DKFZ), Heidelberg 69120, Germany
| | - Mathias Bockwoldt
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Tromsø 9037, Norway
| | - Bernadette Carroll
- School of Biochemistry, Biomedical Sciences Building, University Walk, Bristol BS8 1TD, UK
| | - Suvagata Roy Chowdhury
- Cell Signaling and Metabolism Group, German Cancer Research Center (DKFZ), Heidelberg 69120, Germany
| | - Andreas von Deimling
- German Consortium of Translational Cancer Research (DKTK), Clinical Cooperation Unit Neuropathology, German Cancer Research Center (DKFZ), Heidelberg 69120, Germany; Department of Neuropathology, Institute of Pathology, Heidelberg University, Heidelberg 69120, Germany
| | - Constantinos Demetriades
- Cell Growth Control in Health and Age-Related Disease Group, Max Planck Institute for Biology of Ageing (MPI-AGE), Cologne 50931, Germany; CECAD Cluster of Excellence, University of Cologne, Cologne 50931, Germany
| | - Gianluca Figlia
- Signal Transduction in Cancer and Metabolism, German Cancer Research Center (DKFZ), Heidelberg 69120, Germany; Heidelberg University, Heidelberg 69120, Germany
| | | | - Alexander M Heberle
- Department of Pediatrics, Section Systems Medicine of Metabolism and Signaling, University of Groningen, University Medical Center Groningen, Groningen 9700 RB, The Netherlands; Institute of Biochemistry and Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck 6020, Austria
| | - Ines Heiland
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Tromsø 9037, Norway
| | - Birgit Holzwarth
- Department of Bioinformatics and Molecular Genetics (Faculty of Biology), University of Freiburg, Freiburg 79104, Germany
| | - Lukas A Huber
- Institute of Cell Biology, Biocenter, Medical University of Innsbruck, Innsbruck 6020, Austria; Austrian Drug Screening Institute (ADSI), Innsbruck 6020, Austria
| | - Jacek Jaworski
- Laboratory of Molecular and Cellular Neurobiology, International Institute of Molecular and Cell Biology in Warsaw, Warsaw 02-109, Poland
| | - Magdalena Kedra
- Laboratory of Molecular and Cellular Neurobiology, International Institute of Molecular and Cell Biology in Warsaw, Warsaw 02-109, Poland
| | - Katharina Kern
- Brain Cancer Metabolism Group, German Consortium of Translational Cancer Research (DKTK) & German Cancer Research Center (DKFZ), Heidelberg 69120, Germany
| | - Andrii Kopach
- Laboratory of Molecular and Cellular Neurobiology, International Institute of Molecular and Cell Biology in Warsaw, Warsaw 02-109, Poland
| | - Viktor I Korolchuk
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Ineke van 't Land-Kuper
- Department of Pediatrics, Section Systems Medicine of Metabolism and Signaling, University of Groningen, University Medical Center Groningen, Groningen 9700 RB, The Netherlands; Department for Neuroscience, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, Oldenburg 26129, Germany
| | - Matylda Macias
- Laboratory of Molecular and Cellular Neurobiology, International Institute of Molecular and Cell Biology in Warsaw, Warsaw 02-109, Poland
| | - Mark Nellist
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam 3015 GD, The Netherlands
| | - Wilhelm Palm
- Cell Signaling and Metabolism Group, German Cancer Research Center (DKFZ), Heidelberg 69120, Germany
| | - Stefan Pusch
- German Consortium of Translational Cancer Research (DKTK), Clinical Cooperation Unit Neuropathology, German Cancer Research Center (DKFZ), Heidelberg 69120, Germany; Department of Neuropathology, Institute of Pathology, Heidelberg University, Heidelberg 69120, Germany
| | - Jose Miguel Ramos Pittol
- Institute of Biochemistry and Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck 6020, Austria
| | - Michèle Reil
- Brain Cancer Metabolism Group, German Consortium of Translational Cancer Research (DKTK) & German Cancer Research Center (DKFZ), Heidelberg 69120, Germany
| | - Anja Reintjes
- Institute of Biochemistry and Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck 6020, Austria
| | - Friederike Reuter
- Brain Cancer Metabolism Group, German Consortium of Translational Cancer Research (DKTK) & German Cancer Research Center (DKFZ), Heidelberg 69120, Germany
| | - Julian R Sampson
- Institute of Medical Genetics, Division of Cancer and Genetics, Cardiff University Medical School, Cardiff CF14 4AY, UK
| | - Chloë Scheldeman
- Laboratory for Molecular Biodiscovery, Department of Pharmaceutical and Pharmacological Sciences, University of Leuven, Leuven BE-3000, Belgium; Neurogenetics Research Group, VUB, Brussels 1090, Belgium
| | - Aleksandra Siekierska
- Laboratory for Molecular Biodiscovery, Department of Pharmaceutical and Pharmacological Sciences, University of Leuven, Leuven BE-3000, Belgium
| | - Eduard Stefan
- Institute of Biochemistry and Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck 6020, Austria
| | - Aurelio A Teleman
- Signal Transduction in Cancer and Metabolism, German Cancer Research Center (DKFZ), Heidelberg 69120, Germany; Heidelberg University, Heidelberg 69120, Germany
| | - Laura E Thomas
- Institute of Life Science, Swansea University, Swansea SA2 8PP, UK
| | - Omar Torres-Quesada
- Institute of Biochemistry and Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck 6020, Austria
| | - Saskia Trump
- Molecular Epidemiology Unit, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health (BIH), Berlin 13353, Germany
| | - Hannah D West
- Institute of Medical Genetics, Division of Cancer and Genetics, Cardiff University Medical School, Cardiff CF14 4AY, UK
| | - Peter de Witte
- Laboratory for Molecular Biodiscovery, Department of Pharmaceutical and Pharmacological Sciences, University of Leuven, Leuven BE-3000, Belgium
| | - Sandra Woltering
- Brain Cancer Metabolism Group, German Consortium of Translational Cancer Research (DKTK) & German Cancer Research Center (DKFZ), Heidelberg 69120, Germany
| | - Teodor E Yordanov
- Institute of Cell Biology, Biocenter, Medical University of Innsbruck, Innsbruck 6020, Austria; Division of Cell and Developmental Biology, Institute for Molecular Bioscience, University of Queensland, St Lucia QLD 4072, Australia
| | - Justyna Zmorzynska
- Laboratory of Molecular and Cellular Neurobiology, International Institute of Molecular and Cell Biology in Warsaw, Warsaw 02-109, Poland
| | - Christiane A Opitz
- Brain Cancer Metabolism Group, German Consortium of Translational Cancer Research (DKTK) & German Cancer Research Center (DKFZ), Heidelberg 69120, Germany; Department of Neurology, University Hospital Heidelberg and National Center for Tumor Diseases, Heidelberg 69120, Germany.
| | - Kathrin Thedieck
- Department of Pediatrics, Section Systems Medicine of Metabolism and Signaling, University of Groningen, University Medical Center Groningen, Groningen 9700 RB, The Netherlands; Department for Neuroscience, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, Oldenburg 26129, Germany; Institute of Biochemistry and Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck 6020, Austria.
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29
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Banono NS, Gawel K, De Witte L, Esguerra CV. Zebrafish Larvae Carrying a Splice Variant Mutation in cacna1d: A New Model for Schizophrenia-Like Behaviours? Mol Neurobiol 2021; 58:877-894. [PMID: 33057948 PMCID: PMC7843589 DOI: 10.1007/s12035-020-02160-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 10/02/2020] [Indexed: 12/16/2022]
Abstract
Persons with certain single nucleotide polymorphisms (SNPs) in the CACNA1D gene (encoding voltage-gated calcium channel subunit alpha 1-D) have increased risk of developing neuropsychiatric disorders such as bipolar, schizophrenia and autism. The molecular consequences of SNPs on gene expression and protein function are not well understood. Thus, the use of animal models to determine genotype-phenotype correlations is critical to understanding disease pathogenesis. Here, we describe the behavioural changes in larval zebrafish carrying an essential splice site mutation (sa17298) in cacna1da. Heterozygous mutation resulted in 50% reduction of splice variants 201 and 202 (haploinsufficiency), while homozygosity increased transcript levels of variant 201 above wild type (WT; gain-of-function, GOF). Due to low homozygote viability, we focused primarily on performing the phenotypic analysis on heterozygotes. Indeed, cacna1dasa17298/WT larvae displayed hyperlocomotion-a behaviour characterised in zebrafish as a surrogate phenotype for epilepsy, anxiety or psychosis-like behaviour. Follow-up tests ruled out anxiety or seizures, however, as neither thigmotaxis defects nor epileptiform-like discharges in larval brains were observed. We therefore focused on testing for potential "psychosis-like" behaviour by assaying cacna1dasa17298/WT larval locomotor activity under constant light, during light-dark transition and in startle response to dark flashes. Furthermore, exposure of larvae to the antipsychotics, risperidone and haloperidol reversed cacna1da-induced hyperactivity to WT levels while valproate decreased but did not reverse hyperactivity. Together, these findings demonstrate that cacna1da haploinsufficiency induces behaviours in larval zebrafish analogous to those observed in rodent models of psychosis. Future studies on homozygous mutants will determine how cacna1d GOF alters behaviour in this context.
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Affiliation(s)
- Nancy Saana Banono
- Chemical Neuroscience Group, Centre for Molecular Medicine Norway (NCMM), Faculty of Medicine, University of Oslo, Gaustadalléen 21, Forskningsparken, 0349, Oslo, Norway
| | - Kinga Gawel
- Chemical Neuroscience Group, Centre for Molecular Medicine Norway (NCMM), Faculty of Medicine, University of Oslo, Gaustadalléen 21, Forskningsparken, 0349, Oslo, Norway
- Department of Experimental and Clinical Pharmacology, Medical University of Lublin, Jaczewskiego Str. 8b, 20-090, Lublin, Poland
| | - Linus De Witte
- Pharmaceutical and Biological Sciences, AP Hogeschool Antwerpen, Antwerp, Belgium
| | - Camila V Esguerra
- Chemical Neuroscience Group, Centre for Molecular Medicine Norway (NCMM), Faculty of Medicine, University of Oslo, Gaustadalléen 21, Forskningsparken, 0349, Oslo, Norway.
- School of Pharmacy, Faculty of Mathematics and Natural Sciences, University of Oslo, Sem Sælandsvei 24, 0371, Oslo, Norway.
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30
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Yaksi E, Jamali A, Diaz Verdugo C, Jurisch-Yaksi N. Past, present and future of zebrafish in epilepsy research. FEBS J 2021; 288:7243-7255. [PMID: 33394550 DOI: 10.1111/febs.15694] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 12/17/2020] [Accepted: 12/31/2020] [Indexed: 12/17/2022]
Abstract
Animal models contribute greatly to our understanding of brain development and function as well as its dysfunction in neurological diseases. Epilepsy research is a very good example of how animal models can provide us with a mechanistic understanding of the genes, molecules, and pathophysiological processes involved in disease. Over the course of the last two decades, zebrafish came in as a new player in epilepsy research, with an expanding number of laboratories using this animal to understand epilepsy and to discover new strategies for preventing seizures. Yet, zebrafish as a model offers a lot more for epilepsy research. In this viewpoint, we aim to highlight some key contributions of zebrafish to epilepsy research, and we want to emphasize the great untapped potential of this animal model for expanding these contributions. We hope that our suggestions will trigger further discussions between clinicians and researchers with a common goal to understand and cure epilepsy.
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Affiliation(s)
- Emre Yaksi
- Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway
| | - Ahmed Jamali
- Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway.,Department of Neurology and Clinical Neurophysiology, St Olav University Hospital, Trondheim, Norway
| | - Carmen Diaz Verdugo
- Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway
| | - Nathalie Jurisch-Yaksi
- Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway.,Department of Neurology and Clinical Neurophysiology, St Olav University Hospital, Trondheim, Norway.,Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway
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31
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Balagura G, Cacciatore M, Grasso EA, Striano P, Verrotti A. Fenfluramine for the Treatment of Dravet Syndrome and Lennox-Gastaut Syndrome. CNS Drugs 2020; 34:1001-1007. [PMID: 32875491 DOI: 10.1007/s40263-020-00755-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The last 50 years has seen the introduction of a great number of antiepileptic drugs, relieving the burden of seizures for many patients. However, some conditions remain a challenge for epileptologists, especially Dravet syndrome and Lennox-Gastaut syndrome, which are severe epileptic and developmental encephalopathies characterized by multiple seizure types and electroencephalographic abnormalities that are often unresponsive to combinations of antiepileptic drugs. The re-purposing of an old drug such as fenfluramine could provide an indispensable tool for clinicians, especially because only a few drugs have been tested in relatively homogeneous populations, like Dravet syndrome. It could also provide insights into precision medicine approaches to the treatment of epileptic syndromes. We searched for relevant papers within MEDLINE, EMBASE, and the Clinical Trial Database, considering publications through July 2020. Pre-clinical studies show a mechanism of action for fenfluramine that goes beyond its pro-serotoninergic activity and that is at the intersection of several pathways involved in excitation/inhibition balance. From the ongoing clinical trial data, it is evident that fenfluramine is proving to be a promising antiepileptic drug with very favorable pharmacokinetics and with a good overall safety profile when used at a lower dosage (0.2-0.7 mg/kg/day), despite its previously link to major cardiac adverse events that prompted its withdrawal from the market in 1997. Here, we review the experimental and clinical evidence of the efficacy of fenfluramine, including the latest results from ongoing clinical trials, and critically discuss the future potential of fenfluramine in terms of safety and precision medicine. Available data from the literature suggest a very good efficacy for both epileptic syndromes with a reduction in seizure burden and a longer seizure-free interval. We note the higher prevalence of evidence in patients with Dravet syndrome. Fenfluramine has been used in association with both first- and second-line medications, while its use in monotherapy still needs to be assessed.
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Affiliation(s)
- Ganna Balagura
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, and Maternal and Child Health, University of Genoa, Genoa, Italy.,Pediatric Neurology and Muscular Diseases Unit, IRCCS 'G. Gaslini' Institute, Genoa, Italy
| | - Marta Cacciatore
- Department of Pediatrics, University of L'Aquila, Via Vetoio 1, 67100, Coppito, L'Aquila, Italy.,Department of Pediatrics, University of Chieti, Chieti, Italy
| | - Eleonora A Grasso
- Department of Pediatrics, University of L'Aquila, Via Vetoio 1, 67100, Coppito, L'Aquila, Italy.,Department of Pediatrics, University of Chieti, Chieti, Italy
| | - Pasquale Striano
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, and Maternal and Child Health, University of Genoa, Genoa, Italy.,Pediatric Neurology and Muscular Diseases Unit, IRCCS 'G. Gaslini' Institute, Genoa, Italy
| | - Alberto Verrotti
- Department of Pediatrics, University of L'Aquila, Via Vetoio 1, 67100, Coppito, L'Aquila, Italy.
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32
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Takai A, Yamaguchi M, Yoshida H, Chiyonobu T. Investigating Developmental and Epileptic Encephalopathy Using Drosophila melanogaster. Int J Mol Sci 2020; 21:ijms21176442. [PMID: 32899411 PMCID: PMC7503973 DOI: 10.3390/ijms21176442] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Revised: 08/30/2020] [Accepted: 09/01/2020] [Indexed: 12/16/2022] Open
Abstract
Developmental and epileptic encephalopathies (DEEs) are the spectrum of severe epilepsies characterized by early-onset, refractory seizures occurring in the context of developmental regression or plateauing. Early infantile epileptic encephalopathy (EIEE) is one of the earliest forms of DEE, manifesting as frequent epileptic spasms and characteristic electroencephalogram findings in early infancy. In recent years, next-generation sequencing approaches have identified a number of monogenic determinants underlying DEE. In the case of EIEE, 85 genes have been registered in Online Mendelian Inheritance in Man as causative genes. Model organisms are indispensable tools for understanding the in vivo roles of the newly identified causative genes. In this review, we first present an overview of epilepsy and its genetic etiology, especially focusing on EIEE and then briefly summarize epilepsy research using animal and patient-derived induced pluripotent stem cell (iPSC) models. The Drosophila model, which is characterized by easy gene manipulation, a short generation time, low cost and fewer ethical restrictions when designing experiments, is optimal for understanding the genetics of DEE. We therefore highlight studies with Drosophila models for EIEE and discuss the future development of their practical use.
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Affiliation(s)
- Akari Takai
- Department of Pediatrics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan;
| | - Masamitsu Yamaguchi
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 603-8585, Japan; (M.Y.); (H.Y.)
- Kansai Gakken Laboratory, Kankyo Eisei Yakuhin Co. Ltd., Kyoto 619-0237, Japan
| | - Hideki Yoshida
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 603-8585, Japan; (M.Y.); (H.Y.)
| | - Tomohiro Chiyonobu
- Department of Pediatrics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan;
- Correspondence:
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33
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Gawel K, Kukula-Koch W, Nieoczym D, Stepnik K, van der Ent W, Banono NS, Tarabasz D, Turski WA, Esguerra CV. The Influence of Palmatine Isolated from Berberis sibirica Radix on Pentylenetetrazole-Induced Seizures in Zebrafish. Cells 2020; 9:cells9051233. [PMID: 32429356 PMCID: PMC7290958 DOI: 10.3390/cells9051233] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 05/11/2020] [Accepted: 05/14/2020] [Indexed: 12/15/2022] Open
Abstract
Palmatine (PALM) and berberine (BERB) are widely identified isoquinoline alkaloids among the representatives of the Berberidaceae botanical family. The antiseizure activity of BERB was shown previously in experimental epilepsy models. We assessed the effect of PALM in a pentylenetetrazole (PTZ)-induced seizure assay in zebrafish, with BERB as an active reference compound. Both alkaloids were isolated from the methanolic root extract of Berberis sibirica by counter-current chromatography, and their ability to cross the blood–brain barrier was determined via quantitative structure–activity relationship assay. PALM exerted antiseizure activity, as confirmed by electroencephalographic analysis, and decreased c-fos and bdnf levels in PTZ-treated larvae. In a behavioral assay, PALM dose-dependently decreased PTZ-induced hyperlocomotion. The combination of PALM and BERB in ED16 doses revealed hyperadditive activity towards PTZ-induced hyperlocomotion. Notably, we have indicated that both alkaloids may exert their anticonvulsant activity through different mechanisms of action. Additionally, the combination of both alkaloids in a 1:2.17 ratio (PALM: BERB) mimicked the activity of the pure extract, which indicates that these two active compounds are responsible for its anticonvulsive activity. In conclusion, our study reveals for the first time the anticonvulsant activity of PALM and suggests the combination of PALM and BERB may have higher therapeutic value than separate usage of these compounds.
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Affiliation(s)
- Kinga Gawel
- Chemical Neuroscience Group, Faculty of Medicine, Centre for Molecular Medicine Norway, University of Oslo, Gaustadalléen 21, 0349 Oslo, Norway; (W.v.d.E.); (N.S.B.); (C.V.E.)
- Department of Experimental and Clinical Pharmacology, Medical University of Lublin, Jaczewskiego Str. 8b, 20-090 Lublin, Poland;
- Correspondence: ; Tel.: +48-81448-6454
| | - Wirginia Kukula-Koch
- Chair and Department of Pharmacognosy, Medical University of Lublin, 1, Chodzki Str. 1, 20-093 Lublin, Poland; (W.K.-K.); (D.T.)
| | - Dorota Nieoczym
- Department of Animal Physiology and Pharmacology, Institute of Biology and Biochemistry, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, Akademicka Str. 19, 20-033 Lublin, Poland;
| | - Katarzyna Stepnik
- Department of Physical Chemistry, Institute of Chemical Sciences, Faculty of Chemistry, Maria Curie-Skłodowska University, Pl. M. Curie-Skłodowskiej 3/243, 20-031 Lublin, Poland;
| | - Wietske van der Ent
- Chemical Neuroscience Group, Faculty of Medicine, Centre for Molecular Medicine Norway, University of Oslo, Gaustadalléen 21, 0349 Oslo, Norway; (W.v.d.E.); (N.S.B.); (C.V.E.)
| | - Nancy Saana Banono
- Chemical Neuroscience Group, Faculty of Medicine, Centre for Molecular Medicine Norway, University of Oslo, Gaustadalléen 21, 0349 Oslo, Norway; (W.v.d.E.); (N.S.B.); (C.V.E.)
| | - Dominik Tarabasz
- Chair and Department of Pharmacognosy, Medical University of Lublin, 1, Chodzki Str. 1, 20-093 Lublin, Poland; (W.K.-K.); (D.T.)
| | - Waldemar A. Turski
- Department of Experimental and Clinical Pharmacology, Medical University of Lublin, Jaczewskiego Str. 8b, 20-090 Lublin, Poland;
| | - Camila V. Esguerra
- Chemical Neuroscience Group, Faculty of Medicine, Centre for Molecular Medicine Norway, University of Oslo, Gaustadalléen 21, 0349 Oslo, Norway; (W.v.d.E.); (N.S.B.); (C.V.E.)
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Auvin S, Avbersek A, Bast T, Chiron C, Guerrini R, Kaminski RM, Lagae L, Muglia P, Cross JH. Drug Development for Rare Paediatric Epilepsies: Current State and Future Directions. Drugs 2020; 79:1917-1935. [PMID: 31734883 DOI: 10.1007/s40265-019-01223-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Rare diseases provide a challenge in the evaluation of new therapies. However, orphan drug development is of increasing interest because of the legislation enabling facilitated support by regulatory agencies through scientific advice, and the protection of the molecules with orphan designation. In the landscape of the rare epilepsies, very few syndromes, namely Dravet syndrome, Lennox-Gastaut syndrome and West syndrome, have been subject to orphan drug development. Despite orphan designations for rare epilepsies having dramatically increased in the past 10 years, the number of approved drugs remains limited and restricted to a handful of epilepsy syndromes. In this paper, we describe the current state of orphan drug development for rare epilepsies. We identified a large number of compounds currently under investigation, but mostly in the same rare epilepsy syndromes as in the past. A rationale for further development in rare epilepsies could be based on the match between the drug mechanisms of action and the knowledge of the causative gene mutation or by evidence from animal models. In case of the absence of strong pathophysiological hypotheses, exploratory/basket clinical studies could be helpful to identify a subpopulation that may benefit from the new drug. We provide some suggestions for future improvements in orphan drug development such as promoting paediatric drug investigations, better evaluation of the incidence and the prevalence, together with the natural history data, and the development of new primary outcomes.
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Affiliation(s)
- Stéphane Auvin
- PROTECT, INSERM U1141, Université de Paris, Paris, France. .,Service de Neurologie Pédiatrique, AP-HP, Hôpital Universitaire Robert-Debré, 48, Boulevard Sérurier, 75935, Paris Cedex 19, France.
| | | | - Thomas Bast
- The Kork Epilepsy Center, Kehl-Kork, Germany.,Medical Faculty of the University of Freiburg, Freiburg, Germany
| | - Catherine Chiron
- PROTECT, INSERM U1141, Université de Paris, Paris, France.,Service de Neurologie Pédiatrique, AP-HP, Hôpital Necker-Enfanst Malades, Paris, France
| | - Renzo Guerrini
- Neuroscience Department, Children's Hospital Anna Meyer-University of Florence, Florence, Italy
| | - Rafal M Kaminski
- UCB Pharma, Braine-l'Alleud, Belgium.,Roche Pharma Research and Early Development (pRED), Roche Innovation Center, Basel, Switzerland
| | - Lieven Lagae
- Department Development and Regeneration, Section Paediatric Neurology, University Hospitals, University of Leuven, Leuven, Belgium
| | | | - J Helen Cross
- UCL NIHR BRC Great Ormond Street Institute of Child Health, London, UK
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Specchio N, Pietrafusa N, Ferretti A, Trivisano M, Vigevano F. Successful use of fenfluramine in nonconvulsive status epilepticus of Dravet syndrome. Epilepsia 2020; 61:831-833. [DOI: 10.1111/epi.16474] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 02/17/2020] [Accepted: 02/20/2020] [Indexed: 11/28/2022]
Affiliation(s)
- Nicola Specchio
- Rare and Complex Epilepsy Unit Department of Neuroscience Bambino Gesù Children’s Hospital, Scientific Institute for Research and Health Care RomeItaly
| | - Nicola Pietrafusa
- Rare and Complex Epilepsy Unit Department of Neuroscience Bambino Gesù Children’s Hospital, Scientific Institute for Research and Health Care RomeItaly
| | - Alessandro Ferretti
- Rare and Complex Epilepsy Unit Department of Neuroscience Bambino Gesù Children’s Hospital, Scientific Institute for Research and Health Care RomeItaly
| | - Marina Trivisano
- Rare and Complex Epilepsy Unit Department of Neuroscience Bambino Gesù Children’s Hospital, Scientific Institute for Research and Health Care RomeItaly
| | - Federico Vigevano
- Department of Neuroscience Bambino Gesù Children’s Hospital, Scientific Institute for Research and Health Care Rome, Italy
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36
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Weuring WJ, Singh S, Volkers L, Rook MB, van ‘t Slot RH, Bosma M, Inserra M, Vetter I, Verhoeven-Duif NM, Braun KPJ, Rivara M, Koeleman BPC. NaV1.1 and NaV1.6 selective compounds reduce the behavior phenotype and epileptiform activity in a novel zebrafish model for Dravet Syndrome. PLoS One 2020; 15:e0219106. [PMID: 32134913 PMCID: PMC7058281 DOI: 10.1371/journal.pone.0219106] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Accepted: 02/04/2020] [Indexed: 12/03/2022] Open
Abstract
Dravet syndrome is caused by dominant loss-of-function mutations in SCN1A which cause reduced activity of Nav1.1 leading to lack of neuronal inhibition. On the other hand, gain-of-function mutations in SCN8A can lead to a severe epileptic encephalopathy subtype by over activating NaV1.6 channels. These observations suggest that Nav1.1 and Nav1.6 represent two opposing sides of the neuronal balance between inhibition and activation. Here, we hypothesize that Dravet syndrome may be treated by either enhancing Nav1.1 or reducing Nav1.6 activity. To test this hypothesis we generated and characterized a novel DS zebrafish model and tested new compounds that selectively activate or inhibit the human NaV1.1 or NaV1.6 channel respectively. We used CRISPR/Cas9 to generate two separate Scn1Lab knockout lines as an alternative to previous zebrafish models generated by random mutagenesis or morpholino oligomers. Using an optimized locomotor assay, spontaneous burst movements were detected that were unique to Scn1Lab knockouts and disappear when introducing human SCN1A mRNA. Besides the behavioral phenotype, Scn1Lab knockouts show sudden, electrical discharges in the brain that indicate epileptic seizures in zebrafish. Scn1Lab knockouts showed increased sensitivity to the GABA antagonist pentylenetetrazole and a reduction in whole organism GABA levels. Drug screenings further validated a Dravet syndrome phenotype. We tested the NaV1.1 activator AA43279 and two novel NaV1.6 inhibitors MV1369 and MV1312 in the Scn1Lab knockouts. Both type of compounds significantly reduced the number of spontaneous burst movements and seizure activity. Our results show that selective inhibition of NaV1.6 could be just as efficient as selective activation of NaV1.1 and these approaches could prove to be novel potential treatment strategies for Dravet syndrome and other (genetic) epilepsies. Compounds tested in zebrafish however, should always be further validated in other model systems for efficacy in mammals and to screen for potential side effects.
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Affiliation(s)
- Wout J. Weuring
- Department of Genetics, Center for Molecular Medicine, UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Sakshi Singh
- Department of Genetics, Center for Molecular Medicine, UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Linda Volkers
- Department of Cardiology, Laboratory of Experimental Cardiology, University Medical Centre Leiden, Leiden, the Netherlands
| | - Martin B. Rook
- Department of Medical Physiology, University Medical Centre Utrecht, Utrecht, the Netherlands
| | - Ruben H. van ‘t Slot
- Department of Genetics, Center for Molecular Medicine, UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Marjolein Bosma
- Department of Genetics, Center for Molecular Medicine, UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Marco Inserra
- Centre for Pain Research & School of Pharmacy, University of Queensland, Brisbane, Australia
| | - Irina Vetter
- Centre for Pain Research & School of Pharmacy, University of Queensland, Brisbane, Australia
| | - Nanda M. Verhoeven-Duif
- Department of Genetics, Center for Molecular Medicine, UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Kees P. J. Braun
- Department of Neurology, University Medical Centre Utrecht, Utrecht, the Netherlands
| | - Mirko Rivara
- Food and Drug Department, University of Parma, Parma, Italy
| | - Bobby P. C. Koeleman
- Department of Genetics, Center for Molecular Medicine, UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
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Tiraboschi E, Martina S, van der Ent W, Grzyb K, Gawel K, Cordero-Maldonado ML, Poovathingal SK, Heintz S, Satheesh SV, Brattespe J, Xu J, Suster M, Skupin A, Esguerra CV. New insights into the early mechanisms of epileptogenesis in a zebrafish model of Dravet syndrome. Epilepsia 2020; 61:549-560. [PMID: 32096222 DOI: 10.1111/epi.16456] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 02/03/2020] [Accepted: 02/03/2020] [Indexed: 12/17/2022]
Abstract
OBJECTIVE To pinpoint the earliest cellular defects underlying seizure onset (epileptogenic period) during perinatal brain development in a new zebrafish model of Dravet syndrome (DS) and to investigate potential disease-modifying activity of the 5HT2 receptor agonist fenfluramine. METHODS We used CRISPR/Cas9 mutagenesis to introduce a missense mutation, designed to perturb ion transport function in all channel isoforms, into scn1lab, the zebrafish orthologue of SCN1A (encoding voltage-gated sodium channel alpha subunit 1). We performed behavioral analysis and electroencephalographic recordings to measure convulsions and epileptiform discharges, followed by single-cell RNA-Seq, morphometric analysis of transgenic reporter-labeled γ-aminobutyric acidergic (GABAergic) neurons, and pharmacological profiling of mutant larvae. RESULTS Homozygous mutant (scn1labmut/mut ) larvae displayed spontaneous seizures with interictal, preictal, and ictal discharges (mean = 7.5 per 20-minute recording; P < .0001; one-way analysis of variance). Drop-Seq analysis revealed a 2:1 shift in the ratio of glutamatergic to GABAergic neurons in scn1labmut/mut larval brains versus wild type (WT), with dynamic changes in neuronal, glial, and progenitor cell populations. To explore disease pathophysiology further, we quantified dendritic arborization in GABAergic neurons and observed a 40% reduction in arbor number compared to WT (P < .001; n = 15 mutant, n = 16 WT). We postulate that the significant reduction in inhibitory arbors causes an inhibitory to excitatory neurotransmitter imbalance that contributes to seizures and enhanced electrical brain activity in scn1labmut/mut larvae (high-frequency range), with subsequent GABAergic neuronal loss and astrogliosis. Chronic fenfluramine administration completely restored dendritic arbor numbers to normal in scn1labmut/mut larvae, whereas similar treatment with the benzodiazepine diazepam attenuated seizures, but was ineffective in restoring neuronal cytoarchitecture. BrdU labeling revealed cell overproliferation in scn1labmut/mut larval brains that were rescued by fenfluramine but not diazepam. SIGNIFICANCE Our findings provide novel insights into early mechanisms of DS pathogenesis, describe dynamic cell population changes in the scn1labmut/mut brain, and present first-time evidence for potential disease modification by fenfluramine.
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Affiliation(s)
- Ettore Tiraboschi
- Chemical Neuroscience Group, Center for Molecular Medicine Norway, University of Oslo, Oslo, Norway
| | - Silvia Martina
- Integrative Cell Signaling Group, Luxembourg Center for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Wietske van der Ent
- Chemical Neuroscience Group, Center for Molecular Medicine Norway, University of Oslo, Oslo, Norway
| | - Kamil Grzyb
- Integrative Cell Signaling Group, Luxembourg Center for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Kinga Gawel
- Chemical Neuroscience Group, Center for Molecular Medicine Norway, University of Oslo, Oslo, Norway.,Department of Experimental and Clinical Pharmacology, Medical University of Lublin, Lublin, Poland
| | - Maria Lorena Cordero-Maldonado
- Integrative Cell Signaling Group, Luxembourg Center for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Suresh Kumar Poovathingal
- Integrative Cell Signaling Group, Luxembourg Center for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Sarah Heintz
- Chemical Neuroscience Group, Center for Molecular Medicine Norway, University of Oslo, Oslo, Norway
| | | | - Jarle Brattespe
- Department of Biological Sciences, University of Bergen, Bergen, Norway
| | - Ju Xu
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | | | - Alexander Skupin
- Integrative Cell Signaling Group, Luxembourg Center for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Camila V Esguerra
- Chemical Neuroscience Group, Center for Molecular Medicine Norway, University of Oslo, Oslo, Norway.,Department of Pharmacy, University of Oslo, Oslo, Norway
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38
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Cheresiz SV, Volgin AD, Kokorina Evsyukova A, Bashirzade AAO, Demin KA, de Abreu MS, Amstislavskaya TG, Kalueff AV. Understanding neurobehavioral genetics of zebrafish. J Neurogenet 2020; 34:203-215. [PMID: 31902276 DOI: 10.1080/01677063.2019.1698565] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Due to its fully sequenced genome, high genetic homology to humans, external fertilization, fast development, transparency of embryos, low cost and active reproduction, the zebrafish (Danio rerio) has become a novel promising model organism in biomedicine. Zebrafish are a useful tool in genetic and neuroscience research, including linking various genetic mutations to brain mechanisms using forward and reverse genetics. These approaches have produced novel models of rare genetic CNS disorders and common brain illnesses, such as addiction, aggression, anxiety and depression. Genetically modified zebrafish also foster neuroanatomical studies, manipulating neural circuits and linking them to different behaviors. Here, we discuss recent advances in neurogenetics of zebrafish, and evaluate their unique strengths, inherent limitations and the rapidly growing potential for elucidating the conserved roles of genes in neuropsychiatric disorders.
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Affiliation(s)
- Sergey V Cheresiz
- Scientific Research Institute of Physiology and Basic Medicine, Novosibirsk, Russia.,Institute of Medicine and Psychology, Novosibirsk State University, Novosibirsk, Russia
| | - Andrey D Volgin
- Scientific Research Institute of Physiology and Basic Medicine, Novosibirsk, Russia.,Institute of Medicine and Psychology, Novosibirsk State University, Novosibirsk, Russia
| | - Alexandra Kokorina Evsyukova
- Scientific Research Institute of Physiology and Basic Medicine, Novosibirsk, Russia.,Institute of Medicine and Psychology, Novosibirsk State University, Novosibirsk, Russia
| | - Alim A O Bashirzade
- Scientific Research Institute of Physiology and Basic Medicine, Novosibirsk, Russia.,Institute of Medicine and Psychology, Novosibirsk State University, Novosibirsk, Russia
| | - Konstantin A Demin
- Institute of Experimental Medicine, Almazov National Medical Research Centre, St. Petersburg, Russia.,Institute of Translational Biomedicine, St. Petersburg State University, St. Petersburg, Russia
| | - Murilo S de Abreu
- Bioscience Institute, University of Passo Fundo, Passo Fundo, Brazil.,The International Zebrafish Neuroscience Research Consortium (ZNRC), Slidell, LA, USA
| | - Tamara G Amstislavskaya
- Scientific Research Institute of Physiology and Basic Medicine, Novosibirsk, Russia.,Institute of Medicine and Psychology, Novosibirsk State University, Novosibirsk, Russia.,The International Zebrafish Neuroscience Research Consortium (ZNRC), Slidell, LA, USA
| | - Allan V Kalueff
- School of Pharmacy, Southwest University, Chongqing, China.,Ural Federal University, Ekaterinburg, Russia.,Laboratory of Biological Psychiatry, Institute of Translational Biomedicine, St. Petersburg State University, St. Petersburg, Russia.,Russian Scientific Center of Radiology and Surgical Technologies, Ministry of Healthcare of Russian Federation, St. Petersburg, Russia
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39
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Burrows DRW, Samarut É, Liu J, Baraban SC, Richardson MP, Meyer MP, Rosch RE. Imaging epilepsy in larval zebrafish. Eur J Paediatr Neurol 2020; 24:70-80. [PMID: 31982307 PMCID: PMC7035958 DOI: 10.1016/j.ejpn.2020.01.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 01/03/2020] [Accepted: 01/04/2020] [Indexed: 12/19/2022]
Abstract
Our understanding of the genetic aetiology of paediatric epilepsies has grown substantially over the last decade. However, in order to translate improved diagnostics to personalised treatments, there is an urgent need to link molecular pathophysiology in epilepsy to whole-brain dynamics in seizures. Zebrafish have emerged as a promising new animal model for epileptic seizure disorders, with particular relevance for genetic and developmental epilepsies. As a novel model organism for epilepsy research they combine key advantages: the small size of larval zebrafish allows high throughput in vivo experiments; the availability of advanced genetic tools allows targeted modification to model specific human genetic disorders (including genetic epilepsies) in a vertebrate system; and optical access to the entire central nervous system has provided the basis for advanced microscopy technologies to image structure and function in the intact larval zebrafish brain. There is a growing body of literature describing and characterising features of epileptic seizures and epilepsy in larval zebrafish. Recently genetically encoded calcium indicators have been used to investigate the neurobiological basis of these seizures with light microscopy. This approach offers a unique window into the multiscale dynamics of epileptic seizures, capturing both whole-brain dynamics and single-cell behaviour concurrently. At the same time, linking observations made using calcium imaging in the larval zebrafish brain back to an understanding of epileptic seizures largely derived from cortical electrophysiological recordings in human patients and mammalian animal models is non-trivial. In this review we briefly illustrate the state of the art of epilepsy research in zebrafish with particular focus on calcium imaging of epileptic seizures in the larval zebrafish. We illustrate the utility of a dynamic systems perspective on the epileptic brain for providing a principled approach to linking observations across species and identifying those features of brain dynamics that are most relevant to epilepsy. In the following section we survey the literature for imaging features associated with epilepsy and epileptic seizures and link these to observations made from humans and other more traditional animal models. We conclude by identifying the key challenges still facing epilepsy research in the larval zebrafish and indicate strategies for future research to address these and integrate more directly with the themes and questions that emerge from investigating epilepsy in other model systems and human patients.
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Affiliation(s)
- D R W Burrows
- MRC Centre for Neurodevelopmental Disorders, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - É Samarut
- Department of Neurosciences, Research Center of the University of Montreal Hospital Center, Montreal, Quebec, Canada
| | - J Liu
- Department of Neurological Surgery and Weill Institute for Neuroscience, University of California, San Francisco, San Francisco, CA, USA
| | - S C Baraban
- Department of Neurological Surgery and Weill Institute for Neuroscience, University of California, San Francisco, San Francisco, CA, USA
| | - M P Richardson
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - M P Meyer
- MRC Centre for Neurodevelopmental Disorders, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK; Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - R E Rosch
- MRC Centre for Neurodevelopmental Disorders, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK; Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Department of Paediatric Neurology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK.
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40
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Gawel K, Turski WA, van der Ent W, Mathai BJ, Kirstein-Smardzewska KJ, Simonsen A, Esguerra CV. Phenotypic Characterization of Larval Zebrafish (Danio rerio) with Partial Knockdown of the cacna1a Gene. Mol Neurobiol 2019; 57:1904-1916. [PMID: 31875924 PMCID: PMC7118054 DOI: 10.1007/s12035-019-01860-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 12/15/2019] [Indexed: 12/18/2022]
Abstract
The CACNA1A gene encodes the pore-forming α1 subunit of voltage-gated P/Q type Ca2+ channels (Cav2.1). Mutations in this gene, among others, have been described in patients and rodents suffering from absence seizures and episodic ataxia type 2 with/without concomitant seizures. In this study, we aimed for the first time to assess phenotypic and behavioral alterations in larval zebrafish with partial cacna1aa knockdown, placing special emphasis on changes in epileptiform-like electrographic discharges in larval brains. Whole-mount in situ hybridization analysis revealed expression of cacna1aa in the optic tectum and medulla oblongata of larval zebrafish at 4 and 5 days post-fertilization. Next, microinjection of two antisense morpholino oligomers (individually or in combination) targeting all splice variants of cacna1aa into fertilized zebrafish eggs resulted in dose-dependent mortality and decreased or absent touch response. Over 90% knockdown of cacna1aa on protein level induced epileptiform-like discharges in the optic tectum of larval zebrafish brains. Incubation of morphants with antiseizure drugs (sodium valproate, ethosuximide, lamotrigine, topiramate) significantly decreased the number and, in some cases, cumulative duration of epileptiform-like discharges. In this context, sodium valproate seemed to be the least effective. Carbamazepine did not affect the number and duration of epileptiform-like discharges. Altogether, our data indicate that cacna1aa loss-of-function zebrafish may be considered a new model of absence epilepsy and may prove useful both for the investigation of Cacna1a-mediated epileptogenesis and for in vivo drug screening.
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Affiliation(s)
- Kinga Gawel
- Chemical Neuroscience Group, Centre for Molecular Medicine Norway, Faculty of Medicine, University of Oslo, Gaustadalléen 21, Forskningsparken, 0349, Oslo, Norway.,Department of Experimental and Clinical Pharmacology, Medical University of Lublin, Jaczewskiego St. 8b, 20-090, Lublin, Poland
| | - Waldemar A Turski
- Department of Experimental and Clinical Pharmacology, Medical University of Lublin, Jaczewskiego St. 8b, 20-090, Lublin, Poland
| | - Wietske van der Ent
- Chemical Neuroscience Group, Centre for Molecular Medicine Norway, Faculty of Medicine, University of Oslo, Gaustadalléen 21, Forskningsparken, 0349, Oslo, Norway
| | - Benan J Mathai
- Faculty of Medicine, Institute of Basic Medical Sciences and Centre for Cancer Cell Reprogramming, Institute of Clinical Medicine, University of Oslo, 1112 Blindern, 0317, Oslo, Norway
| | - Karolina J Kirstein-Smardzewska
- Chemical Neuroscience Group, Centre for Molecular Medicine Norway, Faculty of Medicine, University of Oslo, Gaustadalléen 21, Forskningsparken, 0349, Oslo, Norway
| | - Anne Simonsen
- Faculty of Medicine, Institute of Basic Medical Sciences and Centre for Cancer Cell Reprogramming, Institute of Clinical Medicine, University of Oslo, 1112 Blindern, 0317, Oslo, Norway
| | - Camila V Esguerra
- Chemical Neuroscience Group, Centre for Molecular Medicine Norway, Faculty of Medicine, University of Oslo, Gaustadalléen 21, Forskningsparken, 0349, Oslo, Norway. .,School of Pharmacy, Faculty of Mathematics and Natural Sciences, University of Oslo, Sem Sælandsvei 24, 0371, Oslo, Norway.
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41
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Brenet A, Hassan-Abdi R, Somkhit J, Yanicostas C, Soussi-Yanicostas N. Defective Excitatory/Inhibitory Synaptic Balance and Increased Neuron Apoptosis in a Zebrafish Model of Dravet Syndrome. Cells 2019; 8:cells8101199. [PMID: 31590334 PMCID: PMC6829503 DOI: 10.3390/cells8101199] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 09/04/2019] [Accepted: 10/03/2019] [Indexed: 12/22/2022] Open
Abstract
Dravet syndrome is a type of severe childhood epilepsy that responds poorly to current anti-epileptic drugs. In recent years, zebrafish disease models with Scn1Lab sodium channel deficiency have been generated to seek novel anti-epileptic drug candidates, some of which are currently undergoing clinical trials. However, the spectrum of neuronal deficits observed following Scn1Lab depletion in zebrafish larvae has not yet been fully explored. To fill this gap and gain a better understanding of the mechanisms underlying neuron hyperexcitation in Scn1Lab-depleted larvae, we analyzed neuron activity in vivo using combined local field potential recording and transient calcium uptake imaging, studied the distribution of excitatory and inhibitory synapses and neurons as well as investigated neuron apoptosis. We found that Scn1Lab-depleted larvae displayed recurrent epileptiform seizure events, associating massive synchronous calcium uptakes and ictal-like local field potential bursts. Scn1Lab-depletion also caused a dramatic shift in the neuronal and synaptic balance toward excitation and increased neuronal death. Our results thus provide in vivo evidence suggesting that Scn1Lab loss of function causes neuron hyperexcitation as the result of disturbed synaptic balance and increased neuronal apoptosis.
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Affiliation(s)
- Alexandre Brenet
- Université de Paris, NeuroDiderot, Inserm, F-75019 Paris, France.
| | | | - Julie Somkhit
- Université de Paris, NeuroDiderot, Inserm, F-75019 Paris, France.
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42
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Abstract
Dravet syndrome is a rare but severe epilepsy syndrome that begins in the first year of life with recurrent seizures triggered by fever that are typically prolonged and hemiclonic. The epilepsy is highly drug resistant. Although development is normal at onset, over time, most patients develop moderate-to-severe intellectual disability, behavior disorders, and a characteristic crouch gait. There is a significant mortality, predominantly owing to sudden unexpected death in epilepsy. Complete seizure control is rarely attainable. Initial therapy includes valproic acid and clobazam, but response is typically inadequate. The results of new drugs for Dravet syndrome, including stiripentol, cannabidiol, and fenfluramine, are very promising. Stiripentol was associated with a greater than 50% reduction in convulsive seizure frequency in 71% of cases, when added to valproic acid and clobazam, and also markedly reduced status epilepticus. Pharmaceutical-grade cannabidiol resulted in a median change in monthly motor seizures from baseline of - 36.5%. Fenfluramine was associated with a greater than 50% reduction in seizures of 70%, with one quarter of cases achieving near seizure freedom over the duration of the trial. These agents are generally well tolerated, with few patients discontinuing for adverse effects. There is limited evidence to date regarding improvement in cognition with these newer agents; however, a meaningful change is challenging to assess over short trial periods and requires longer follow-up studies. While current treatments focus predominantly on seizure control, newer therapies including genetic treatments and antisense oligonucleotides can target the SCN1A channelopathy, and thus, may also significantly impact the important co-morbidities associated with this syndrome.
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Affiliation(s)
- Elaine C Wirrell
- Child and Adolescent Neurology, Mayo Clinic, 200 First St SW, Rochester, MN, 55905, USA.
| | - Rima Nabbout
- Hôpital Necker Enfants Malades, Université Paris Descartes, Paris, France
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43
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Silenieks LB, Carroll NK, Van Niekerk A, Van Niekerk E, Taylor C, Upton N, Higgins GA. Evaluation of Selective 5-HT 2C Agonists in Acute Seizure Models. ACS Chem Neurosci 2019; 10:3284-3295. [PMID: 31082204 DOI: 10.1021/acschemneuro.8b00739] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The 5-HT releaser/reuptake inhibitor fenfluramine has been recently reported to provide benefit as an adjunctive treatment for Dravet and Lennox-Gastaut syndromes, two types of severe childhood epilepsy. Despite its enhancement of 5-HT function, many effects of fenfluramine have been demonstrated to be dependent on 5-HT2C receptor activation, suggesting that 5-HT2C receptor activation may have an anticonvulsant property. The present study was designed to evaluate fenfluramine and 5-HT agonists of varying 5-HT2C agonist selectivity, the relatively nonselective mCPP and Ro 60-0175, and the selective 5-HT2C agonists lorcaserin and CP-809101 across a variety of acute seizure tests conducted in adult rats and mice, which have been instrumental in identifying the majority of clinically efficacious antiepileptic drugs. Tests included the maximal electroshock seizure (MES), MES threshold, and 6 Hz electrical convulsive seizure models and the chemoconvulsant pentylenetetrazole test. The effect of mCPP, lorcaserin, and CP-809101 against electrically evoked seizures in amygdala kindled rats was also investigated. Overall, at doses known to interact with 5-HT2CR, there was no clear class-related effect of these agonists in any test. The only notable antiseizure effect of fenfluramine was inhibition of MES-induced tonic seizures in the rat. The current preclinical studies using the classical acute seizure tests and an amygdala kindling model do not identify a reliable antiseizure effect of fenfluramine, an agent now used in the treatment of human epilepsies, including Dravet syndrome and Lennox-Gastaut syndrome. Given the nature of these epilepsies, early life and/or genetic models may have better construct validity and be more appropriate for further study.
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Affiliation(s)
- Leonardo B. Silenieks
- Intervivo Solutions Inc, Toronto, ON M5A 4K2, Canada
- Vivocore, Toronto, ON N1M 2W4, Canada
| | | | | | | | | | - Neil Upton
- Transpharmation Ltd, London NW10NH, United Kingdom
| | - Guy A. Higgins
- Intervivo Solutions Inc, Toronto, ON M5A 4K2, Canada
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON ON M5S, Canada
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de Witte P, Lagae L. Serotonergic modulation as a pharmacological modality in the treatment of Dravet syndrome. Brain 2019; 140:e35. [PMID: 28402511 PMCID: PMC5445252 DOI: 10.1093/brain/awx090] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Accepted: 02/24/2017] [Indexed: 11/12/2022] Open
Affiliation(s)
- Peter de Witte
- Molecular Biodiscovery, Department of Pharmaceutical and Pharmacological Sciences, University of Leuven, Belgium
| | - Lieven Lagae
- Molecular Biodiscovery, Department of Pharmaceutical and Pharmacological Sciences, University of Leuven, Belgium
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45
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Bialer M, Johannessen SI, Koepp MJ, Levy RH, Perucca E, Tomson T, White HS. Progress report on new antiepileptic drugs: A summary of the Fourteenth Eilat Conference on New Antiepileptic Drugs and Devices (EILAT XIV). II. Drugs in more advanced clinical development. Epilepsia 2019; 59:1842-1866. [PMID: 30368788 DOI: 10.1111/epi.14555] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2018] [Revised: 08/05/2018] [Accepted: 08/06/2018] [Indexed: 12/24/2022]
Abstract
The Fourteenth Eilat Conference on New Antiepileptic Drugs and Devices (EILAT XIV) took place in Madrid, Spain, on May 13-16, 2018 and was attended by 168 delegates from 28 countries. The conference provided a forum for professionals involved in basic science, clinical research, regulatory affairs, and clinical care to meet and discuss the latest advances related to discovery and development of drugs and devices aimed at improving the management of people with epilepsy. This progress report provides a summary of findings on investigational compounds for which data from both preclinical studies and studies in patients were presented. The compounds reviewed include anakinra, cannabidiol, cannabidivarin, fenfluramine, ganaxolone, medium-chain fatty acids, padsevonil, and the valproic derivatives valnoctamide and sec-butylpropylacetamide. On June 25, 2018, the US Food and Drug Administration approved a standardized formulation of cannabidiol oral solution for the treatment of seizures associated with Lennox-Gastaut syndrome and Dravet syndrome in patients 2 years and older. The report shows that there continues to be a steady flow of potential antiepileptic drugs progressing to clinical development. Many of these compounds show innovative mechanisms of action, and some have already been tested in placebo-controlled randomized controlled trials, with promising efficacy and safety results.
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Affiliation(s)
- Meir Bialer
- Faculty of Medicine, School of Pharmacy and David R. Bloom Center for Pharmacy, Institute for Drug Research, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Svein I Johannessen
- National Center for Epilepsy, Sandvika, Norway.,Department of Pharmacology, Oslo University Hospital, Oslo, Norway
| | - Matthias J Koepp
- Department of Clinical and Experimental Epilepsy, University College London Institute of Neurology, London, United Kingdom
| | - René H Levy
- Department of Pharmaceutics and Neurological Surgery, University of Washington, Seattle, Washington
| | - Emilio Perucca
- Department of Internal Medicine and Therapeutics, University of Pavia, Pavia, Italy.,IRCCS Mondino Foundation, Pavia, Italy
| | - Torbjörn Tomson
- Department of Clinical Neuroscience, Karolinska Institute, Stockholm, Sweden
| | - H Steve White
- Department of Pharmacy, School of Pharmacy, University of Washington, Seattle, Washington
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Tupal S, Faingold CL. Fenfluramine, a serotonin-releasing drug, prevents seizure-induced respiratory arrest and is anticonvulsant in the DBA/1 mouse model of SUDEP. Epilepsia 2019; 60:485-494. [PMID: 30719703 DOI: 10.1111/epi.14658] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 01/02/2019] [Accepted: 01/07/2019] [Indexed: 02/06/2023]
Abstract
OBJECTIVE Prevention of sudden unexpected death in epilepsy (SUDEP) is a critical goal for epilepsy therapy. The DBA/1 mouse model of SUDEP exhibits an elevated susceptibility to seizure-induced death in response to electroconvulsive shock, hyperthermia, convulsant drug, and acoustic stimulation. The serotonin hypothesis of SUDEP is based on findings that treatments which modify serotonergic function significantly alter susceptibility to seizure-induced sudden death in several epilepsy models, including DBA/1 mice. Serotonergic abnormalities have also recently been observed in human SUDEP. Fenfluramine is a drug that enhances serotonin release in the brain. Recent studies have found that the addition of fenfluramine improved seizure control in patients with Dravet syndrome, which has a high incidence of SUDEP. Therefore, we investigated the effects of fenfluramine on seizures and seizure-induced respiratory arrest (S-IRA) in DBA/1 mice. METHODS The dose and time course of the effects of fenfluramine (i.p.) on audiogenic seizures (Sz) induced by an electric bell in DBA/1 mice were determined. Videos of Sz-induced behaviors were recorded for analysis. Statistical significance (P < 0.05) was evaluated using the chi-square test. RESULTS Sixteen hours after administration of 15 mg/kg of fenfluramine, a high incidence of selective block of S-IRA susceptibility (P < 0.001) occurred in DBA/1 mice without blocking any convulsive behavior. Thirty minutes after 20-40 mg/kg of fenfluramine, significant reductions of seizure incidence and severity, as well as S-IRA susceptibility occurred, which were long-lasting (≥48 hours). The median effective dose (ED50 ) of fenfluramine for significantly reducing Sz at 30 minutes was 21 mg/kg. SIGNIFICANCE This study presents the first evidence for the effectiveness of fenfluramine in reducing seizure incidence, severity, and S-IRA susceptibility in a mammalian SUDEP model. The ability of fenfluramine to block S-IRA selectively suggests the potential usefulness of fenfluramine in prophylaxis of SUDEP. These results further confirm and extend the serotonin hypothesis of SUDEP.
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Affiliation(s)
- Srinivasan Tupal
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, Illinois
| | - Carl L Faingold
- Departments of Pharmacology and Neurology, Southern Illinois University School of Medicine, Springfield, Illinois
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Nieoczym D, Socała K, Gawel K, Esguerra CV, Wyska E, Wlaź P. Anticonvulsant Activity of Pterostilbene in Zebrafish and Mouse Acute Seizure Tests. Neurochem Res 2019; 44:1043-1055. [PMID: 30689162 PMCID: PMC6482291 DOI: 10.1007/s11064-019-02735-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 01/19/2019] [Indexed: 12/29/2022]
Abstract
Pterostilbene (PTE), a natural dimethylated analog of resveratrol, possesses numerous health-beneficial properties. The ability of PTE to cross the blood–brain barrier raised the possibility that this compound may modulate central nervous system functions, including seizure activity. The aim of our study was to investigate the activity of PTE in the larval zebrafish pentylenetetrazole (PTZ) seizure assay and three acute seizure tests in mice, i.e., in the maximal electroshock seizure threshold (MEST), 6 Hz-induced psychomotor seizure threshold and intravenous (iv) PTZ tests. Additionally, potential antidepressant activity of PTE was estimated in the forced swim test in mice. The chimney test was used to determine the influence of PTE on motor coordination in mice, while its influence on neuromuscular strength was assessed in the grip strength test in mice. Locomotor activity was determined to verify the results from the forced swim test. PTE revealed an evident anticonvulsant effect both in zebrafish larvae (10 µM; 2 h-incubation) and mice (at doses of 100 and 200 mg/kg, intraperitoneally) but it did not exhibit antidepressant potential in the forced swim test. Furthermore, it did not cause any statistically significant changes in motor coordination, neuromuscular strength and locomotor activity in mice. In conclusion, our present findings demonstrate for the first time the anticonvulsant potential of PTE. The aforementioned results suggest that it might be employed in epilepsy treatment, however, further precise studies are required to verify its activity in other experimental seizure and epilepsy models and its precise mechanism of action should be determined.
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Affiliation(s)
- Dorota Nieoczym
- Department of Animal Physiology, Institute of Biology and Biochemistry, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, Akademicka 19, 20-033, Lublin, Poland.
| | - Katarzyna Socała
- Department of Animal Physiology, Institute of Biology and Biochemistry, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, Akademicka 19, 20-033, Lublin, Poland
| | - Kinga Gawel
- Chemical Neuroscience Group, Centre for Molecular Medicine Norway, University of Oslo, Gaustadalléen 21, 0349, Oslo, Norway
- Department of Experimental and Clinical Pharmacology, Medical University of Lublin, Jaczewskiego 8b, 20-090, Lublin, Poland
| | - Camila V Esguerra
- Chemical Neuroscience Group, Centre for Molecular Medicine Norway, University of Oslo, Gaustadalléen 21, 0349, Oslo, Norway
| | - Elżbieta Wyska
- Department of Pharmacokinetics and Physical Pharmacy, Collegium Medicum, Jagiellonian University, Kraków, Poland
| | - Piotr Wlaź
- Department of Animal Physiology, Institute of Biology and Biochemistry, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, Akademicka 19, 20-033, Lublin, Poland
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48
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Sakai C, Ijaz S, Hoffman EJ. Zebrafish Models of Neurodevelopmental Disorders: Past, Present, and Future. Front Mol Neurosci 2018; 11:294. [PMID: 30210288 PMCID: PMC6123572 DOI: 10.3389/fnmol.2018.00294] [Citation(s) in RCA: 86] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 08/03/2018] [Indexed: 12/21/2022] Open
Abstract
Zebrafish are increasingly being utilized as a model system to investigate the function of the growing list of risk genes associated with neurodevelopmental disorders. This is due in large part to the unique features of zebrafish that make them an optimal system for this purpose, including rapid, external development of transparent embryos, which enable the direct visualization of the developing nervous system during early stages, large progenies, which provide considerable tractability for performing high-throughput pharmacological screens to identify small molecule suppressors of simple behavioral phenotypes, and ease of genetic manipulation, which has been greatly facilitated by the advent of CRISPR/Cas9 gene editing technologies. This review article focuses on studies that have harnessed these advantages of the zebrafish system for the functional analysis of genes that are strongly associated with the following neurodevelopmental disorders: autism spectrum disorders (ASD), epilepsy, intellectual disability (ID) and schizophrenia. We focus primarily on studies describing early morphological and behavioral phenotypes during embryonic and larval stages resulting from loss of risk gene function. We highlight insights into basic mechanisms of risk gene function gained from these studies as well as limitations of studies to date. Finally, we discuss advances in in vivo neural circuit imaging in zebrafish, which promise to transform research using the zebrafish model by illuminating novel circuit-level mechanisms with relevance to neurodevelopmental disorders.
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Affiliation(s)
- Catalina Sakai
- Child Study Center, Program on Neurogenetics, Yale School of Medicine, Yale University, New Haven, CT, United States
| | - Sundas Ijaz
- Child Study Center, Program on Neurogenetics, Yale School of Medicine, Yale University, New Haven, CT, United States
| | - Ellen J Hoffman
- Child Study Center, Program on Neurogenetics, Yale School of Medicine, Yale University, New Haven, CT, United States.,Department of Neuroscience, Yale School of Medicine, Yale University, New Haven, CT, United States
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49
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Griffin A, Hamling KR, Hong S, Anvar M, Lee LP, Baraban SC. Preclinical Animal Models for Dravet Syndrome: Seizure Phenotypes, Comorbidities and Drug Screening. Front Pharmacol 2018; 9:573. [PMID: 29915537 PMCID: PMC5994396 DOI: 10.3389/fphar.2018.00573] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 05/14/2018] [Indexed: 12/18/2022] Open
Abstract
Epilepsy is a common chronic neurological disease affecting almost 3 million people in the United States and 50 million people worldwide. Despite availability of more than two dozen FDA-approved anti-epileptic drugs (AEDs), one-third of patients fail to receive adequate seizure control. Specifically, pediatric genetic epilepsies are often the most severe, debilitating and pharmaco-resistant forms of epilepsy. Epileptic syndromes share a common symptom of unprovoked seizures. While some epilepsies/forms of epilepsy are the result of acquired insults such as head trauma, febrile seizure, or viral infection, others have a genetic basis. The discovery of epilepsy associated genes suggests varied underlying pathologies and opens the door for development of new "personalized" treatment options for each genetic epilepsy. Among these, Dravet syndrome (DS) has received substantial attention for both the pre-clinical and early clinical development of novel therapeutics. Despite these advances, there is no FDA-approved treatment for DS. Over 80% of patients diagnosed with DS carry a de novo mutation within the voltage-gated sodium channel gene SCN1A and these patients suffer with drug resistant and life-threatening seizures. Here we will review the preclinical animal models for DS featuring inactivation of SCN1A (including zebrafish and mice) with an emphasis on seizure phenotypes and behavioral comorbidities. Because many drugs fail somewhere between initial preclinical discovery and clinical trials, it is equally important that we understand how these models respond to known AEDs. As such, we will also review the available literature and recent drug screening efforts using these models with a focus on assay protocols and predictive pharmacological profiles. Validation of these preclinical models is a critical step in our efforts to efficiently discover new therapies for these patients. The behavioral and electrophysiological drug screening assays in zebrafish will be discussed in detail including specific examples from our laboratory using a zebrafish scn1 mutant and a summary of the nearly 3000 drugs screened to date. As the discovery and development phase rapidly moves from the lab-to-the-clinic for DS, it is hoped that this preclinical strategy offers a platform for how to approach any genetic epilepsy.
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Affiliation(s)
- Aliesha Griffin
- Epilepsy Research Laboratory Department of Neurological Surgery and Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, United States
| | - Kyla R Hamling
- Epilepsy Research Laboratory Department of Neurological Surgery and Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, United States
| | - SoonGweon Hong
- Department of Bioengineering, University of California, Berkeley, Berkeley, CA, United States
| | - Mana Anvar
- Epilepsy Research Laboratory Department of Neurological Surgery and Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, United States
| | - Luke P Lee
- Department of Bioengineering, University of California, Berkeley, Berkeley, CA, United States
| | - Scott C Baraban
- Epilepsy Research Laboratory Department of Neurological Surgery and Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, United States
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50
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Rodríguez-Muñoz M, Sánchez-Blázquez P, Garzón J. Fenfluramine diminishes NMDA receptor-mediated seizures via its mixed activity at serotonin 5HT2A and type 1 sigma receptors. Oncotarget 2018; 9:23373-23389. [PMID: 29805740 PMCID: PMC5955088 DOI: 10.18632/oncotarget.25169] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Accepted: 04/03/2018] [Indexed: 10/27/2022] Open
Abstract
Fenfluramine exhibits antiepileptic properties and thus diminishes epileptiform discharges in experimental animal models of Dravet syndrome. Fenfluramine is metabolized into norfenfluramine in vivo, which shows greater affinity and agonist activity at serotonin 5HT2 receptors (5HT2R) than fenfluramine. In this study, we found that fenfluramine and norfenfluramine disrupted the regulatory association of the sigma 1 receptor (σ1R) with NR1 subunits of glutamate N-methyl-D-aspartate receptors (NMDAR), an effect that was also produced by σ1R antagonists such as S1RA and prevented by σ1R agonists such as PPCC. The antagonists removed σ1R bound to NMDAR NR1 subunits enabling calcium-regulated calmodulin (CaM) to bind to those subunits. As a result, CaM may inhibit calcium permeation through NMDARs. The serotoninergic activity of fenfluramine at 5HT2AR, and likely also at 5HT2CR, collaborated with its activity at σ1Rs to prevent the convulsive syndrome promoted by NMDAR overactivation. Notably, fenfluramine enhanced the inhibitory coupling of G protein-coupled receptors such as 5HT1AR and cannabinoid type 1 receptor with NMDARs, thus allowing the more effective restrain of NMDAR activity. Thus, fenfluramine circumvents the negative side effects of direct NMDAR antagonists and may improve the quality of life of subjects affected by such proconvulsant dysfunctions.
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Affiliation(s)
- María Rodríguez-Muñoz
- Neuropharmacology, Department of Translational Neurosciences, Cajal Institute, CSIC, Madrid E-28002, Spain
| | - Pilar Sánchez-Blázquez
- Neuropharmacology, Department of Translational Neurosciences, Cajal Institute, CSIC, Madrid E-28002, Spain
| | - Javier Garzón
- Neuropharmacology, Department of Translational Neurosciences, Cajal Institute, CSIC, Madrid E-28002, Spain
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