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Almog Y, Mavashov A, Brusel M, Rubinstein M. Functional Investigation of a Neuronal Microcircuit in the CA1 Area of the Hippocampus Reveals Synaptic Dysfunction in Dravet Syndrome Mice. Front Mol Neurosci 2022; 15:823640. [PMID: 35370551 PMCID: PMC8966673 DOI: 10.3389/fnmol.2022.823640] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2021] [Accepted: 02/21/2022] [Indexed: 02/05/2023] Open
Abstract
Dravet syndrome is severe childhood-onset epilepsy, caused by loss of function mutations in the SCN1A gene, encoding for the voltage-gated sodium channel NaV1.1. The leading hypothesis is that Dravet is caused by selective reduction in the excitability of inhibitory neurons, due to hampered activity of NaV1.1 channels in these cells. However, these initial neuronal changes can lead to further network alterations. Here, focusing on the CA1 microcircuit in hippocampal brain slices of Dravet syndrome (DS, Scn1aA1783V/WT) and wild-type (WT) mice, we examined the functional response to the application of Hm1a, a specific NaV1.1 activator, in CA1 stratum-oriens (SO) interneurons and CA1 pyramidal excitatory neurons. DS SO interneurons demonstrated reduced firing and depolarized threshold for action potential (AP), indicating impaired activity. Nevertheless, Hm1a induced a similar AP threshold hyperpolarization in WT and DS interneurons. Conversely, a smaller effect of Hm1a was observed in CA1 pyramidal neurons of DS mice. In these excitatory cells, Hm1a application resulted in WT-specific AP threshold hyperpolarization and increased firing probability, with no effect on DS neurons. Additionally, when the firing of SO interneurons was triggered by CA3 stimulation and relayed via activation of CA1 excitatory neurons, the firing probability was similar in WT and DS interneurons, also featuring a comparable increase in the firing probability following Hm1a application. Interestingly, a similar functional response to Hm1a was observed in a second DS mouse model, harboring the nonsense Scn1aR613X mutation. Furthermore, we show homeostatic synaptic alterations in both CA1 pyramidal neurons and SO interneurons, consistent with reduced excitation and inhibition onto CA1 pyramidal neurons and increased release probability in the CA1-SO synapse. Together, these results suggest global neuronal alterations within the CA1 microcircuit extending beyond the direct impact of NaV1.1 dysfunction.
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Affiliation(s)
- Yael Almog
- Goldschleger Eye Research Institute, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- The Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Anat Mavashov
- Goldschleger Eye Research Institute, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Marina Brusel
- Goldschleger Eye Research Institute, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Moran Rubinstein
- Goldschleger Eye Research Institute, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- The Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
- *Correspondence: Moran Rubinstein,
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102
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Weng OY, Li Y, Wang LY. Modeling Epilepsy Using Human Induced Pluripotent Stem Cells-Derived Neuronal Cultures Carrying Mutations in Ion Channels and the Mechanistic Target of Rapamycin Pathway. Front Mol Neurosci 2022; 15:810081. [PMID: 35359577 PMCID: PMC8960276 DOI: 10.3389/fnmol.2022.810081] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2021] [Accepted: 02/02/2022] [Indexed: 11/17/2022] Open
Abstract
Epilepsy is a neurological disorder that affects over 65 million people globally. It is characterized by periods of seizure activity of the brain as a result of excitation and inhibition (E/I) imbalance, which is regarded as the core underpinning of epileptic activity. Both gain- and loss-of-function (GOF and LOF) mutations of ion channels, synaptic proteins and signaling molecules along the mechanistic target of rapamycin (mTOR) pathway have been linked to this imbalance. The pathogenesis of epilepsy often has its roots in the early stage of brain development. It remains a major challenge to extrapolate the findings from many animal models carrying these GOF or LOF mutations to the understanding of disease mechanisms in the developing human brain. Recent advent of the human pluripotent stem cells (hPSCs) technology opens up a new avenue to recapitulate patient conditions and to identify druggable molecular targets. In the following review, we discuss the progress, challenges and prospects of employing hPSCs-derived neural cultures to study epilepsy. We propose a tentative working model to conceptualize the possible impact of these GOF and LOF mutations in ion channels and mTOR signaling molecules on the morphological and functional remodeling of intrinsic excitability, synaptic transmission and circuits, ultimately E/I imbalance and behavioral phenotypes in epilepsy.
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Affiliation(s)
- Octavia Yifang Weng
- Program in Developmental and Stem Cell Biology, Sick Kids Research Institutes, Toronto, ON, Canada
- Program in Neuroscience and Mental Health, Sick Kids Research Institutes, Toronto, ON, Canada
- Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Yun Li
- Program in Developmental and Stem Cell Biology, Sick Kids Research Institutes, Toronto, ON, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
- *Correspondence: Yun Li,
| | - Lu-Yang Wang
- Program in Neuroscience and Mental Health, Sick Kids Research Institutes, Toronto, ON, Canada
- Department of Physiology, University of Toronto, Toronto, ON, Canada
- Lu-Yang Wang,
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103
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Mattis J, Somarowthu A, Goff KM, Jiang E, Yom J, Sotuyo N, Mcgarry LM, Feng H, Kaneko K, Goldberg EM. Corticohippocampal circuit dysfunction in a mouse model of Dravet syndrome. eLife 2022; 11:e69293. [PMID: 35212623 PMCID: PMC8920506 DOI: 10.7554/elife.69293] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Accepted: 02/24/2022] [Indexed: 11/13/2022] Open
Abstract
Dravet syndrome (DS) is a neurodevelopmental disorder due to pathogenic variants in SCN1A encoding the Nav1.1 sodium channel subunit, characterized by treatment-resistant epilepsy, temperature-sensitive seizures, developmental delay/intellectual disability with features of autism spectrum disorder, and increased risk of sudden death. Convergent data suggest hippocampal dentate gyrus (DG) pathology in DS (Scn1a+/-) mice. We performed two-photon calcium imaging in brain slice to uncover a profound dysfunction of filtering of perforant path input by DG in young adult Scn1a+/- mice. This was not due to dysfunction of DG parvalbumin inhibitory interneurons (PV-INs), which were only mildly impaired at this timepoint; however, we identified enhanced excitatory input to granule cells, suggesting that circuit dysfunction is due to excessive excitation rather than impaired inhibition. We confirmed that both optogenetic stimulation of entorhinal cortex and selective chemogenetic inhibition of DG PV-INs lowered seizure threshold in vivo in young adult Scn1a+/- mice. Optogenetic activation of PV-INs, on the other hand, normalized evoked responses in granule cells in vitro. These results establish the corticohippocampal circuit as a key locus of pathology in Scn1a+/- mice and suggest that PV-INs retain powerful inhibitory function and may be harnessed as a potential therapeutic approach toward seizure modulation.
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Affiliation(s)
- Joanna Mattis
- Department of Neurology, The Perelman School of Medicine at The University of PennsylvaniaPhiladelphiaUnited States
| | - Ala Somarowthu
- Division of Neurology, Department of Pediatrics, The Children’s Hospital of PhiladelphiaPhiladelphiaUnited States
| | - Kevin M Goff
- Neuroscience Graduate Group, The University of Pennsylvania Perelman School of MedicinePhiladelphiaUnited States
| | - Evan Jiang
- Division of Neurology, Department of Pediatrics, The Children’s Hospital of PhiladelphiaPhiladelphiaUnited States
| | - Jina Yom
- College of Arts and Sciences, The University of PennsylvaniaPhiladelphiaUnited States
| | - Nathaniel Sotuyo
- Neuroscience Graduate Group, The University of Pennsylvania Perelman School of MedicinePhiladelphiaUnited States
| | - Laura M Mcgarry
- Division of Neurology, Department of Pediatrics, The Children’s Hospital of PhiladelphiaPhiladelphiaUnited States
| | - Huijie Feng
- Division of Neurology, Department of Pediatrics, The Children’s Hospital of PhiladelphiaPhiladelphiaUnited States
| | - Keisuke Kaneko
- Division of Neurology, Department of Pediatrics, The Children’s Hospital of PhiladelphiaPhiladelphiaUnited States
| | - Ethan M Goldberg
- Department of Neurology, The Perelman School of Medicine at The University of PennsylvaniaPhiladelphiaUnited States
- Division of Neurology, Department of Pediatrics, The Children’s Hospital of PhiladelphiaPhiladelphiaUnited States
- Department of Neuroscience, The Perelman School of Medicine at The University of PennsylvaniaPhiladelphiaUnited States
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104
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Godoy LD, Prizon T, Rossignoli MT, Leite JP, Liberato JL. Parvalbumin Role in Epilepsy and Psychiatric Comorbidities: From Mechanism to Intervention. Front Integr Neurosci 2022; 16:765324. [PMID: 35250498 PMCID: PMC8891758 DOI: 10.3389/fnint.2022.765324] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 01/24/2022] [Indexed: 12/22/2022] Open
Abstract
Parvalbumin is a calcium-binding protein present in inhibitory interneurons that play an essential role in regulating many physiological processes, such as intracellular signaling and synaptic transmission. Changes in parvalbumin expression are deeply related to epilepsy, which is considered one of the most disabling neuropathologies. Epilepsy is a complex multi-factor group of disorders characterized by periods of hypersynchronous activity and hyperexcitability within brain networks. In this scenario, inhibitory neurotransmission dysfunction in modulating excitatory transmission related to the loss of subsets of parvalbumin-expressing inhibitory interneuron may have a prominent role in disrupted excitability. Some studies also reported that parvalbumin-positive interneurons altered function might contribute to psychiatric comorbidities associated with epilepsy, such as depression, anxiety, and psychosis. Understanding the epileptogenic process and comorbidities associated with epilepsy have significantly advanced through preclinical and clinical investigation. In this review, evidence from parvalbumin altered function in epilepsy and associated psychiatric comorbidities were explored with a translational perspective. Some advances in potential therapeutic interventions are highlighted, from current antiepileptic and neuroprotective drugs to cutting edge modulation of parvalbumin subpopulations using optogenetics, designer receptors exclusively activated by designer drugs (DREADD) techniques, transcranial magnetic stimulation, genome engineering, and cell grafting. Creating new perspectives on mechanisms and therapeutic strategies is valuable for understanding the pathophysiology of epilepsy and its psychiatric comorbidities and improving efficiency in clinical intervention.
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Affiliation(s)
- Lívea Dornela Godoy
- Department of Psychology, Faculty of Philosophy, Sciences and Letters of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil
| | - Tamiris Prizon
- Department of Neuroscience and Behavioral Sciences, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Matheus Teixeira Rossignoli
- Department of Neuroscience and Behavioral Sciences, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - João Pereira Leite
- Department of Neuroscience and Behavioral Sciences, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
- João Pereira Leite,
| | - José Luiz Liberato
- Department of Neuroscience and Behavioral Sciences, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
- *Correspondence: José Luiz Liberato,
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105
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Chronic partial TrkB activation reduces seizures and mortality in a mouse model of Dravet syndrome. Proc Natl Acad Sci U S A 2022; 119:2022726119. [PMID: 35165147 PMCID: PMC8851461 DOI: 10.1073/pnas.2022726119] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/29/2021] [Indexed: 12/03/2022] Open
Abstract
Dravet syndrome (DS) is a severe childhood epileptic encephalopathy characterized by intractable seizures and comorbidities, including a high rate of premature mortality. DS is mainly caused by loss-of-function mutations of the Scn1a gene encoding sodium channel Nav1.1 that is predominantly expressed in inhibitory parvalbumin-containing (PV) interneurons. Decreased Nav1.1 impairs PV cell function, causing DS phenotypes. Effective pharmacological therapy targeting defective PV interneurons is currently not available. This study demonstrated that early treatment with a partial TrkB receptor agonist, LM22A-4, increased Nav1.1 expression, improved PV interneuron function, and reduced seizure occurrence and mortality rate in DS mice, suggesting a potential therapy for DS. Dravet syndrome (DS) is one of the most severe childhood epilepsies, characterized by intractable seizures and comorbidities including cognitive and social dysfunction and high premature mortality. DS is mainly caused by loss-of-function mutations in the Scn1a gene encoding Nav1.1 that is predominantly expressed in inhibitory parvalbumin-containing (PV) interneurons. Decreased Nav1.1 impairs PV cell function, contributing to DS phenotypes. Effective pharmacological therapy that targets defective PV interneurons is not available. The known role of brain-derived neurotrophic factor (BDNF) in the development and maintenance of interneurons, together with our previous results showing improved PV interneuronal function and antiepileptogenic effects of a TrkB receptor agonist in a posttraumatic epilepsy model, led to the hypothesis that early treatment with a TrkB receptor agonist might prevent or reduce seizure activity in DS mice. To test this hypothesis, we treated DS mice with LM22A-4 (LM), a partial agonist at the BDNF TrkB receptor, for 7 d starting at postnatal day 13 (P13), before the onset of spontaneous seizures. Results from immunohistochemistry, Western blot, whole-cell patch-clamp recording, and in vivo seizure monitoring showed that LM treatment increased the number of perisomatic PV interneuronal synapses around cortical pyramidal cells in layer V, upregulated Nav1.1 in PV neurons, increased inhibitory synaptic transmission, and decreased seizures and the mortality rate in DS mice. The results suggest that early treatment with a partial TrkB receptor agonist may be a promising therapeutic approach to enhance PV interneuron function and reduce epileptogenesis and premature death in DS.
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106
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Studtmann C, Ladislav M, Topolski MA, Safari M, Swanger SA. NaV1.1 haploinsufficiency impairs glutamatergic and GABAergic neuron function in the thalamus. Neurobiol Dis 2022; 167:105672. [DOI: 10.1016/j.nbd.2022.105672] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 02/08/2022] [Accepted: 02/22/2022] [Indexed: 11/16/2022] Open
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Panagiotakos G, Pasca SP. A matter of space and time: Emerging roles of disease-associated proteins in neural development. Neuron 2022; 110:195-208. [PMID: 34847355 PMCID: PMC8776599 DOI: 10.1016/j.neuron.2021.10.035] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 10/11/2021] [Accepted: 10/25/2021] [Indexed: 01/21/2023]
Abstract
Recent genetic studies of neurodevelopmental disorders point to synaptic proteins and ion channels as key contributors to disease pathogenesis. Although many of these proteins, such as the L-type calcium channel Cav1.2 or the postsynaptic scaffolding protein SHANK3, have well-studied functions in mature neurons, new evidence indicates that they may subserve novel, distinct roles in immature cells as the nervous system is assembled in prenatal development. Emerging tools and technologies, including single-cell sequencing and human cellular models of disease, are illuminating differential isoform utilization, spatiotemporal expression, and subcellular localization of ion channels and synaptic proteins in the developing brain compared with the adult, providing new insights into the regulation of developmental processes. We propose that it is essential to consider the temporally distinct and cell-specific roles of these proteins during development and maturity in our framework for understanding neuropsychiatric disorders.
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Affiliation(s)
- Georgia Panagiotakos
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA; Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, CA, USA; Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, CA, USA.
| | - Sergiu P Pasca
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA; Stanford Brain Organogenesis, Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA, USA.
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108
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Tao E, Corry B. Characterizing fenestration size in sodium channel subtypes and their accessibility to inhibitors. Biophys J 2022; 121:193-206. [PMID: 34958776 PMCID: PMC8790208 DOI: 10.1016/j.bpj.2021.12.025] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2021] [Revised: 12/07/2021] [Accepted: 12/16/2021] [Indexed: 01/21/2023] Open
Abstract
Voltage-gated sodium channels (Nav) underlie the electrical activity of nerve and muscle cells. Humans have nine different subtypes of these channels, which are the target of small-molecule inhibitors commonly used to treat a range of conditions. Structural studies have identified four lateral fenestrations within the Nav pore module that have been shown to influence Nav pore blocker access during resting-state inhibition. However, the structural differences among the nine subtypes are still unclear. In particular, the dimensions of the four individual fenestrations across the Nav subtypes and their differential accessibility to pore blockers is yet to be characterized. To address this, we applied classical molecular dynamics simulations to study the recently published structures of Nav1.1, Nav1.2, Nav1.4, Nav1.5, and Nav1.7. Although there is significant variability in the bottleneck sizes of the Nav fenestrations, the subtypes follow a common pattern, with wider DI-II and DIII-IV fenestrations, a more restricted DII-III fenestration, and the most restricted DI-IV fenestration. We further identify the key bottleneck residues in each fenestration and show that the motions of aromatic residue sidechains govern the bottleneck radii. Well-tempered metadynamics simulations of Nav1.4 and Nav1.5 in the presence of the pore blocker lidocaine also support the DI-II fenestration being the most likely access route for drugs. Our computational results provide a foundation for future in vitro experiments examining the route of drug access to sodium channels. Understanding the fenestrations and their accessibility to drugs is critical for future analyses of diseases mutations across different sodium channel subtypes, with the potential to inform pharmacological development of resting-state inhibitors and subtype-selective drug design.
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Affiliation(s)
- Elaine Tao
- Research School of Biology, Australian National University, Canberra, Australia
| | - Ben Corry
- Research School of Biology, Australian National University, Canberra, Australia.
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109
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Scn1a gene reactivation after symptom onset rescues pathological phenotypes in a mouse model of Dravet syndrome. Nat Commun 2022; 13:161. [PMID: 35013317 PMCID: PMC8748984 DOI: 10.1038/s41467-021-27837-w] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2021] [Accepted: 12/14/2021] [Indexed: 01/02/2023] Open
Abstract
Dravet syndrome is a severe epileptic encephalopathy caused primarily by haploinsufficiency of the SCN1A gene. Repetitive seizures can lead to endurable and untreatable neurological deficits. Whether this severe pathology is reversible after symptom onset remains unknown. To address this question, we generated a Scn1a conditional knock-in mouse model (Scn1a Stop/+) in which Scn1a expression can be re-activated on-demand during the mouse lifetime. Scn1a gene disruption leads to the development of seizures, often associated with sudden unexpected death in epilepsy (SUDEP) and behavioral alterations including hyperactivity, social interaction deficits and cognitive impairment starting from the second/third week of age. However, we showed that Scn1a gene re-activation when symptoms were already manifested (P30) led to a complete rescue of both spontaneous and thermic inducible seizures, marked amelioration of behavioral abnormalities and normalization of hippocampal fast-spiking interneuron firing. We also identified dramatic gene expression alterations, including those associated with astrogliosis in Dravet syndrome mice, that, accordingly, were rescued by Scn1a gene expression normalization at P30. Interestingly, regaining of Nav1.1 physiological level rescued seizures also in adult Dravet syndrome mice (P90) after months of repetitive attacks. Overall, these findings represent a solid proof-of-concept highlighting that disease phenotype reversibility can be achieved when Scn1a gene activity is efficiently reconstituted in brain cells. Dravet syndrome is a devastating epileptic encephalopathy caused by Scn1a gene haploinsufficiency. Exploiting a novel knock-in mouse model, here the authors show that restoring Scn1a expression after symptom onset is sufficient to rescue main phenotypic manifestations of the syndrome.
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110
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Beretta S, Gritti L, Ponzoni L, Scalmani P, Mantegazza M, Sala M, Verpelli C, Sala C. Rescuing epileptic and behavioral alterations in a Dravet syndrome mouse model by inhibiting eukaryotic elongation factor 2 kinase (eEF2K). Mol Autism 2022; 13:1. [PMID: 34980259 PMCID: PMC8722032 DOI: 10.1186/s13229-021-00484-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 12/23/2021] [Indexed: 11/30/2022] Open
Abstract
Background Dravet Syndrome is a severe childhood pharmaco-resistant epileptic disorder mainly caused by mutations in the SCN1A gene, which encodes for the α1 subunit of the type I voltage-gated sodium channel (NaV1.1), that causes imbalance between excitation and inhibition in the brain. We recently found that eEF2K knock out mice displayed enhanced GABAergic transmission and tonic inhibition and were less susceptible to epileptic seizures. Thus, we investigated the effect of inhibition of eEF2K on the epileptic and behavioral phenotype of Scn1a ± mice, a murine model of Dravet Syndrome. Methods To elucidate the role of eEF2K pathway in the etiopathology of Dravet syndrome we generated a new mouse model deleting the eEF2K gene in Scn1a ± mice. By crossing Scn1a ± mice with eEF2K−/− mice we obtained the three main genotypes needed for our studies, Scn1a+/+ eEF2K+/+ (WT mice), Scn1a ± eEF2K+/+ mice (Scn1a ± mice) and Scn1a ± eEF2K−/− mice, that were fully characterized for EEG and behavioral phenotype. Furthermore, we tested the ability of a pharmacological inhibitor of eEF2K in rescuing EEG alterations of the Scn1a ± mice. Results We showed that the activity of eEF2K/eEF2 pathway was enhanced in Scn1a ± mice. Then, we demonstrated that both genetic deletion and pharmacological inhibition of eEF2K were sufficient to ameliorate the epileptic phenotype of Scn1a ± mice. Interestingly we also found that motor coordination defect, memory impairments, and stereotyped behavior of the Scn1a ± mice were reverted by eEF2K deletion. The analysis of spontaneous inhibitory postsynaptic currents (sIPSCs) suggested that the rescue of the pathological phenotype was driven by the potentiation of GABAergic synapses. Limitations Even if we found that eEF2K deletion was able to increase inhibitory synapses function, the molecular mechanism underlining the inhibition of eEF2K/eEF2 pathway in rescuing epileptic and behavioral alterations in the Scn1a ± needs further investigations. Conclusions Our data indicate that pharmacological inhibition of eEF2K could represent a novel therapeutic intervention for treating epilepsy and related comorbidities in the Dravet syndrome. Supplementary Information The online version contains supplementary material available at 10.1186/s13229-021-00484-0.
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Affiliation(s)
- Stefania Beretta
- CNR Neuroscience Institute, Milan, and NeuroMi Milan Center for Neuroscience, Via Raoul Follereau 3, 20854, Vedano al Lambro, MB, Italy
| | - Laura Gritti
- CNR Neuroscience Institute, Milan, and NeuroMi Milan Center for Neuroscience, Via Raoul Follereau 3, 20854, Vedano al Lambro, MB, Italy
| | - Luisa Ponzoni
- CNR Neuroscience Institute, Milan, and NeuroMi Milan Center for Neuroscience, Via Raoul Follereau 3, 20854, Vedano al Lambro, MB, Italy
| | - Paolo Scalmani
- L'Unità Operativa Complessa di Epilettologia Clinica e Sperimentale, Foundation Istituto di Ricerca e Cura a Carattere Scientifico (IRCCS), Neurological Institute Carlo Besta, 20133, Milan, Italy
| | - Massimo Mantegazza
- CNRS UMR 7275, Institut National de La Santé Et de La Recherche Médicale, LabEx ICST, Institute of Molecular and Cellular Pharmacology (IPMC), Université Côte d'Azur (UCA), 06560, Valbonne-Sophia Antipolis, France
| | - Mariaelvina Sala
- CNR Neuroscience Institute, Milan, and NeuroMi Milan Center for Neuroscience, Via Raoul Follereau 3, 20854, Vedano al Lambro, MB, Italy
| | - Chiara Verpelli
- CNR Neuroscience Institute, Milan, and NeuroMi Milan Center for Neuroscience, Via Raoul Follereau 3, 20854, Vedano al Lambro, MB, Italy.
| | - Carlo Sala
- CNR Neuroscience Institute, Milan, and NeuroMi Milan Center for Neuroscience, Via Raoul Follereau 3, 20854, Vedano al Lambro, MB, Italy.
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111
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Teran FA, Bravo E, Richerson GB. Sudden unexpected death in epilepsy: Respiratory mechanisms. HANDBOOK OF CLINICAL NEUROLOGY 2022; 189:153-176. [PMID: 36031303 PMCID: PMC10191258 DOI: 10.1016/b978-0-323-91532-8.00012-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Epilepsy is one of the most common chronic neurologic diseases, with a prevalence of 1% in the US population. Many people with epilepsy live normal lives, but are at risk of sudden unexpected death in epilepsy (SUDEP). This mysterious comorbidity of epilepsy causes premature death in 17%-50% of those with epilepsy. Most SUDEP occurs after a generalized seizure, and patients are typically found in bed in the prone position. Until recently, it was thought that SUDEP was due to cardiovascular failure, but patients who died while being monitored in hospital epilepsy units revealed that most SUDEP is due to postictal central apnea. Some cases may occur when seizures invade the amygdala and activate projections to the brainstem. Evidence suggests that the pathophysiology is linked to defects in the serotonin system and central CO2 chemoreception, and that there is considerable overlap with mechanisms thought to be involved in sudden infant death syndrome (SIDS). Future work is needed to identify biomarkers for patients at highest risk, improve ascertainment, develop methods to alert caregivers when SUDEP is imminent, and find effective approaches to prevent these fatal events.
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Affiliation(s)
- Frida A Teran
- Department of Neurology, University of Iowa, Iowa City, IA, United States; Medical Scientist Training Program, University of Iowa, Iowa City, IA, United States.
| | - Eduardo Bravo
- Department of Neurology, University of Iowa, Iowa City, IA, United States
| | - George B Richerson
- Department of Neurology, University of Iowa, Iowa City, IA, United States; Department of Molecular Physiology & Biophysics, University of Iowa, Iowa City, IA, United States
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112
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Juarez P, Martínez Cerdeño V. Parvalbumin and parvalbumin chandelier interneurons in autism and other psychiatric disorders. Front Psychiatry 2022; 13:913550. [PMID: 36311505 PMCID: PMC9597886 DOI: 10.3389/fpsyt.2022.913550] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 09/22/2022] [Indexed: 11/13/2022] Open
Abstract
Parvalbumin (PV) is a calcium binding protein expressed by inhibitory fast-spiking interneurons in the cerebral cortex. By generating a fast stream of action potentials, PV+ interneurons provide a quick and stable inhibitory input to pyramidal neurons and contribute to the generation of gamma oscillations in the cortex. Their fast-firing rates, while advantageous for regulating cortical signaling, also leave them vulnerable to metabolic stress. Chandelier (Ch) cells are a type of PV+ interneuron that modulate the output of pyramidal neurons and synchronize spikes within neuron populations by directly innervating the pyramidal axon initial segment. Changes in the morphology and/or function of PV+ interneurons, mostly of Ch cells, are linked to neurological disorders. In ASD, the number of PV+ Ch cells is decreased across several cortical areas. Changes in the morphology and/or function of PV+ interneurons have also been linked to schizophrenia, epilepsy, and bipolar disorder. Herein, we review the role of PV and PV+ Ch cell alterations in ASD and other psychiatric disorders.
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Affiliation(s)
- Pablo Juarez
- Institute for Pediatric Regenerative Medicine (IPRM), Shriners Hospital for Children and UC Davis School of Medicine, Sacramento, CA, United States.,Department of Pathology and Laboratory Medicine, UC Davis School of Medicine, Sacramento, CA, United States
| | - Verónica Martínez Cerdeño
- Institute for Pediatric Regenerative Medicine (IPRM), Shriners Hospital for Children and UC Davis School of Medicine, Sacramento, CA, United States.,Department of Pathology and Laboratory Medicine, UC Davis School of Medicine, Sacramento, CA, United States.,MIND Institute, UC Davis School of Medicine, Sacramento, CA, United States
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113
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Sparber P, Mikhaylova S, Galkina V, Itkis Y, Skoblov M. Case Report: Functional Investigation of an Undescribed Missense Variant Affecting Splicing in a Patient With Dravet Syndrome. Front Neurol 2021; 12:761892. [PMID: 34938262 PMCID: PMC8686832 DOI: 10.3389/fneur.2021.761892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 11/02/2021] [Indexed: 11/22/2022] Open
Abstract
Pathogenic variants in the SCN1A gene are associated with a spectrum of epileptic disorders ranging in severity from familial febrile seizures to Dravet syndrome. Large proportions of reported pathogenic variants in SCN1A are annotated as missense variants and are often classified as variants of uncertain significance when no functional data are available. Although loss-of-function variants are associated with a more severe phenotype in SCN1A, the molecular mechanism of single nucleotide variants is often not clear, and genotype-phenotype correlations in SCN1A-related epilepsy remain uncertain. Coding variants can affect splicing by creating novel cryptic splicing sites in exons or by disrupting exonic cis-regulation elements crucial for proper pre-mRNA splicing. Here, we report a novel case of Dravet syndrome caused by an undescribed missense variant, c.4852G>A (p.(Gly1618Ser)). By midigene splicing assay, we demonstrated that the identified variant is in fact splice-affecting. To our knowledge, this is the first report on the functional investigation of a missense variant affecting splicing in Dravet syndrome.
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Affiliation(s)
- Peter Sparber
- Laboratory of Functional Genomics, Research Centre for Medical Genetics, Moscow, Russia
| | - Svetlana Mikhaylova
- Medical Genetics Department, Russian Children's Clinical Hospital, Moscow, Russia
| | - Varvara Galkina
- Clinical Department, Research Centre for Medical Genetics, Moscow, Russia
| | - Yulia Itkis
- Laboratory of Inherited Metabolic Disorders, Research Centre for Medical Genetics, Moscow, Russia
| | - Mikhail Skoblov
- Laboratory of Functional Genomics, Research Centre for Medical Genetics, Moscow, Russia
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114
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Xu C, Zhang Y, Gozal D, Carney P. Channelopathy of Dravet Syndrome and Potential Neuroprotective Effects of Cannabidiol. J Cent Nerv Syst Dis 2021; 13:11795735211048045. [PMID: 34992485 PMCID: PMC8724990 DOI: 10.1177/11795735211048045] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Dravet syndrome (DS) is a channelopathy, neurodevelopmental, epileptic encephalopathy characterized by seizures, developmental delay, and cognitive impairment that includes susceptibility to thermally induced seizures, spontaneous seizures, ataxia, circadian rhythm and sleep disorders, autistic-like behaviors, and premature death. More than 80% of DS cases are linked to mutations in genes which encode voltage-gated sodium channel subunits, SCN1A and SCN1B, which encode the Nav1.1α subunit and Nav1.1β1 subunit, respectively. There are other gene mutations encoding potassium, calcium, and hyperpolarization-activated cyclic nucleotide-gated (HCN) channels related to DS. One-third of patients have pharmacoresistance epilepsy. DS is unresponsive to standard therapy. Cannabidiol (CBD), a non-psychoactive phytocannabinoid present in Cannabis, has been introduced for treating DS because of its anticonvulsant properties in animal models and humans, especially in pharmacoresistant patients. However, the etiological channelopathiological mechanism of DS and action mechanism of CBD on the channels are unclear. In this review, we summarize evidence of the direct and indirect action mechanism of sodium, potassium, calcium, and HCN channels in DS, especially sodium subunits. Some channels' loss-of-function or gain-of-function in inhibitory or excitatory neurons determine the balance of excitatory and inhibitory are associated with DS. A great variety of mechanisms of CBD anticonvulsant effects are focused on modulating these channels, especially sodium, calcium, and potassium channels, which will shed light on ionic channelopathy of DS and the precise molecular treatment of DS in the future.
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Affiliation(s)
- Changqing Xu
- Department of Child Health and the Child Health Research Institute, School of Medicine, University of Missouri, Columbia, MO, USA
| | - Yumin Zhang
- Department of Anatomy, Physiology and Genetics; Department of Neuroscience, Uniformed Services University School of Medicine, Bethesda, MD, USA
| | - David Gozal
- Department of Child Health and the Child Health Research Institute, School of Medicine, University of Missouri, Columbia, MO, USA
| | - Paul Carney
- Departments of Child Health and Neurology, School of Medicine, University of Missouri, Columbia, MO, USA
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115
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Dvorak NM, Tapia CM, Singh AK, Baumgartner TJ, Wang P, Chen H, Wadsworth PA, Zhou J, Laezza F. Pharmacologically Targeting the Fibroblast Growth Factor 14 Interaction Site on the Voltage-Gated Na + Channel 1.6 Enables Isoform-Selective Modulation. Int J Mol Sci 2021; 22:ijms222413541. [PMID: 34948337 PMCID: PMC8708424 DOI: 10.3390/ijms222413541] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Revised: 12/15/2021] [Accepted: 12/15/2021] [Indexed: 01/05/2023] Open
Abstract
Voltage-gated Na+ (Nav) channels are the primary molecular determinant of the action potential. Among the nine isoforms of the Nav channel α subunit that have been described (Nav1.1-Nav1.9), Nav1.1, Nav1.2, and Nav1.6 are the primary isoforms expressed in the central nervous system (CNS). Crucially, these three CNS Nav channel isoforms display differential expression across neuronal cell types and diverge with respect to their subcellular distributions. Considering these differences in terms of their localization, the CNS Nav channel isoforms could represent promising targets for the development of targeted neuromodulators. However, current therapeutics that target Nav channels lack selectivity, which results in deleterious side effects due to modulation of off-target Nav channel isoforms. Among the structural components of the Nav channel α subunit that could be pharmacologically targeted to achieve isoform selectivity, the C-terminal domains (CTD) of Nav channels represent promising candidates on account of displaying appreciable amino acid sequence divergence that enables functionally unique protein–protein interactions (PPIs) with Nav channel auxiliary proteins. In medium spiny neurons (MSNs) of the nucleus accumbens (NAc), a critical brain region of the mesocorticolimbic circuit, the PPI between the CTD of the Nav1.6 channel and its auxiliary protein fibroblast growth factor 14 (FGF14) is central to the generation of electrical outputs, underscoring its potential value as a site for targeted neuromodulation. Focusing on this PPI, we previously developed a peptidomimetic derived from residues of FGF14 that have an interaction site on the CTD of the Nav1.6 channel. In this work, we show that whereas the compound displays dose-dependent effects on the activity of Nav1.6 channels in heterologous cells, the compound does not affect Nav1.1 or Nav1.2 channels at comparable concentrations. In addition, we show that the compound correspondingly modulates the action potential discharge and the transient Na+ of MSNs of the NAc. Overall, these results demonstrate that pharmacologically targeting the FGF14 interaction site on the CTD of the Nav1.6 channel is a strategy to achieve isoform-selective modulation, and, more broadly, that sites on the CTDs of Nav channels interacted with by auxiliary proteins could represent candidates for the development of targeted therapeutics.
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116
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Marco Hernández AV, Tomás Vila M, Caro Llopis A, Monfort S, Martinez F. Case Report: Novel Homozygous Likely Pathogenic SCN1A Variant With Autosomal Recessive Inheritance and Review of the Literature. Front Neurol 2021; 12:784892. [PMID: 34917021 PMCID: PMC8669891 DOI: 10.3389/fneur.2021.784892] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 10/20/2021] [Indexed: 11/17/2022] Open
Abstract
Dominant pathogenic variations in the SCN1A gene are associated with several neuro developmental disorders with or without epilepsy, including Dravet syndrome (DS). Conversely, there are few published cases with homozygous or compound heterozygous variations in the SCN1A gene. Here, we describe two siblings from a consanguineous pedigree with epilepsy phenotype compatible with genetic epilepsy with febrile seizures plus (GEFS+) associated with the homozygous likely pathogenic variant (NM_001165963.1): c.4513A > C (p.Lys1505Gln). Clinical and genetic data were compared to those of other 10 previously published patients with epilepsy and variants in compound heterozygosity or homozygosity in the SCN1A gene. Most patients (11/12) had missense variants. Patients in whom the variants were located at the cytoplasmic or the extracellular domains frequently presented a less severe phenotype than those in whom they are located at the pore-forming domains. Five of the patients (41.7%) meet clinical criteria for Dravet syndrome (DS), one of them associated acute encephalopathy. Other five patients (41.7%) had a phenotype of epilepsy with febrile seizures plus familial origin, while the two remaining (17%) presented focal epileptic seizures. SCN1A-related epilepsies present in most cases an autosomal dominant inheritance; however, there is growing evidence that some genetic variants only manifest clinical symptoms when they are present in both alleles, following an autosomal recessive inheritance.
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Affiliation(s)
- Ana Victoria Marco Hernández
- Neuropediatrics Section, Hospital Universitari i Politècnic La Fe, Valencia, Spain
- Genetics Unit, Hospital Universitari i Politècnic La Fe, Valencia, Spain
| | - Miguel Tomás Vila
- Neuropediatrics Section, Hospital Universitari i Politècnic La Fe, Valencia, Spain
| | - Alfonso Caro Llopis
- Genetics Unit, Hospital Universitari i Politècnic La Fe, Valencia, Spain
- Genomics Unit, La Fe Health Research Institute, Valencia, Spain
| | - Sandra Monfort
- Genomics Unit, La Fe Health Research Institute, Valencia, Spain
| | - Francisco Martinez
- Genetics Unit, Hospital Universitari i Politècnic La Fe, Valencia, Spain
- Genomics Unit, La Fe Health Research Institute, Valencia, Spain
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117
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Tapia A, Giachello CN, Palomino-Schätzlein M, Baines RA, Galindo MI. Generation and Characterization of the Drosophila melanogaster paralytic Gene Knock-Out as a Model for Dravet Syndrome. Life (Basel) 2021; 11:life11111261. [PMID: 34833136 PMCID: PMC8619338 DOI: 10.3390/life11111261] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 11/11/2021] [Accepted: 11/17/2021] [Indexed: 12/13/2022] Open
Abstract
Dravet syndrome is a severe rare epileptic disease caused by mutations in the SCN1A gene coding for the Nav1.1 protein, a voltage-gated sodium channel alpha subunit. We have made a knock-out of the paralytic gene, the single Drosophila melanogaster gene encoding this type of protein, by homologous recombination. These flies showed a heat-induced seizing phenotype, and sudden death in long term seizures. In addition to seizures, neuromuscular alterations were observed in climbing, flight, and walking tests. Moreover, they also manifested some cognitive alterations, such as anxiety and problems in learning. Electrophysiological analyses from larval motor neurons showed a decrease in cell capacitance and membrane excitability, while persistent sodium current increased. To detect alterations in metabolism, we performed an NMR metabolomic profiling of heads, which revealed higher levels in some amino acids, succinate, and lactate; and also an increase in the abundance of GABA, which is the main neurotransmitter implicated in Dravet syndrome. All these changes in the paralytic knock-out flies indicate that this is a good model for epilepsy and specifically for Dravet syndrome. This model could be a new tool to understand the pathophysiology of the disease and to find biomarkers, genetic modifiers and new treatments.
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Affiliation(s)
- Andrea Tapia
- Centro de Investigación Príncipe Felipe, 46012 Valencia, Spain; (A.T.); (M.P.-S.)
| | - Carlo N. Giachello
- Manchester Academic Health Science Centre, Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PL, UK; (C.N.G.); (R.A.B.)
| | | | - Richard A. Baines
- Manchester Academic Health Science Centre, Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PL, UK; (C.N.G.); (R.A.B.)
| | - Máximo Ibo Galindo
- Centro de Investigación Príncipe Felipe, 46012 Valencia, Spain; (A.T.); (M.P.-S.)
- Instituto Interuniversitario de Investigación de Reconocimiento Molecular y Desarrollo Tecnológico (IDM), Universitat Politècnica de València, Universitat de València, 46022 Valencia, Spain
- UPV-CIPF Joint Unit Disease Mechanisms and Nanomedicine, 46012 Valencia, Spain
- Correspondence:
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118
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Layer N, Sonnenberg L, Pardo González E, Benda J, Hedrich UBS, Lerche H, Koch H, Wuttke TV. Dravet Variant SCN1A A1783V Impairs Interneuron Firing Predominantly by Altered Channel Activation. Front Cell Neurosci 2021; 15:754530. [PMID: 34776868 PMCID: PMC8581729 DOI: 10.3389/fncel.2021.754530] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 09/28/2021] [Indexed: 11/23/2022] Open
Abstract
Dravet syndrome (DS) is a developmental epileptic encephalopathy mainly caused by functional NaV1.1 haploinsufficiency in inhibitory interneurons. Recently, a new conditional mouse model expressing the recurrent human p.(Ala1783Val) missense variant has become available. In this study, we provided an electrophysiological characterization of this variant in tsA201 cells, revealing both altered voltage-dependence of activation and slow inactivation without reduced sodium peak current density. Based on these data, simulated interneuron (IN) firing properties in a conductance-based single-compartment model suggested surprisingly similar firing deficits for NaV1.1A1783V and full haploinsufficiency as caused by heterozygous truncation variants. Impaired NaV1.1A1783V channel activation was predicted to have a significantly larger impact on channel function than altered slow inactivation and is therefore proposed as the main mechanism underlying IN dysfunction. The computational model was validated in cortical organotypic slice cultures derived from conditional Scn1aA1783V mice. Pan-neuronal activation of the p.Ala1783V in vitro confirmed a predicted IN firing deficit and revealed an accompanying reduction of interneuronal input resistance while demonstrating normal excitability of pyramidal neurons. Altered input resistance was fed back into the model for further refinement. Taken together these data demonstrate that primary loss of function (LOF) gating properties accompanied by altered membrane characteristics may match effects of full haploinsufficiency on the neuronal level despite maintaining physiological peak current density, thereby causing DS.
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Affiliation(s)
- Nikolas Layer
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Lukas Sonnenberg
- Institute for Neurobiology, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Emilio Pardo González
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Jan Benda
- Institute for Neurobiology, Eberhard Karls University Tübingen, Tübingen, Germany.,Bernstein Center for Computational Neuroscience, Eberhard Karls Universitat, Tübingen, Germany
| | - Ulrike B S Hedrich
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Holger Lerche
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Henner Koch
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany.,Department of Epileptology, Neurology, Rheinisch-Westfälische Technische Hochschule Aachen, Aachen, Germany
| | - Thomas V Wuttke
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany.,Department of Neurosurgery, University of Tübingen, Tübingen, Germany
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119
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Cheah CS, Beckman MA, Catterall WA, Oakley JC. Sharp-Wave Ripple Frequency and Interictal Epileptic Discharges Increase in Tandem During Thermal Induction of Seizures in a Mouse Model of Genetic Epilepsy. Front Cell Neurosci 2021; 15:751762. [PMID: 34733140 PMCID: PMC8558377 DOI: 10.3389/fncel.2021.751762] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 09/28/2021] [Indexed: 11/13/2022] Open
Abstract
Dravet Syndrome (DS) is a genetic, infantile-onset epilepsy with refractory seizures and severe cognitive impairment. While network level pathophysiology is poorly understood, work in genetic mouse models of DS reveals selective reduction of inhibitory interneuron excitability, a likely mechanism of seizures and comorbidities. Consistent with the critical role of interneurons in timing and recruitment of network activity, hippocampal sharp wave ripples (SPW-R)—interneuron dependent compound brain rhythms essential for spatial learning and memory—are less frequent and ripple frequency is slower in DS mice, both likely to impair cognitive performance. Febrile seizures are characteristic of DS, reflecting a temperature-dependent shift in excitation–inhibition balance. DS interneurons are sensitive to depolarization block and may fall silent with increased excitation precipitating epileptic transformation of ripples. To determine the temperature dependence of SWP-R features and relationship of SPW-R to hippocampal interictal activity, we recorded hippocampal local field potentials in a DS mouse model and wildtype littermate controls while increasing core body temperature. In both genotypes, temperature elevation speeds ripple frequency, although DS ripples remain consistently slower. The rate of SPW-R also increases in both genotypes but subsequently falls in DS mice as interictal epileptic activity simultaneously increases preceding a thermally-evoked seizure. Epileptic events occur intermixed with SPW-R, some during SPW-R burst complexes, and transiently suppress SPW-R occurrence suggesting shared network elements. Together these data demonstrate a temperature dependence of SPW-R rate and ripple frequency and suggest a pathophysiologic mechanism by which elevated temperature transforms a normal brain rhythm into epileptic event.
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Affiliation(s)
- Christine S Cheah
- Department of Neurology, University of Washington, Seattle, WA, United States
| | - Megan A Beckman
- Department of Pharmacology, University of Washington, Seattle, WA, United States
| | - William A Catterall
- Department of Pharmacology, University of Washington, Seattle, WA, United States
| | - John C Oakley
- Department of Neurology, University of Washington, Seattle, WA, United States.,Department of Pharmacology, University of Washington, Seattle, WA, United States
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120
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Auffenberg E, Hedrich UB, Barbieri R, Miely D, Groschup B, Wuttke TV, Vogel N, Lührs P, Zanardi I, Bertelli S, Spielmann N, Gailus-Durner V, Fuchs H, Hrabě de Angelis M, Pusch M, Dichgans M, Lerche H, Gavazzo P, Plesnila N, Freilinger T. Hyperexcitable interneurons trigger cortical spreading depression in an Scn1a migraine model. J Clin Invest 2021; 131:142202. [PMID: 34546973 PMCID: PMC8553559 DOI: 10.1172/jci142202] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 09/02/2021] [Indexed: 12/12/2022] Open
Abstract
Cortical spreading depression (CSD), a wave of depolarization followed by depression of cortical activity, is a pathophysiological process implicated in migraine with aura and various other brain pathologies, such as ischemic stroke and traumatic brain injury. To gain insight into the pathophysiology of CSD, we generated a mouse model for a severe monogenic subtype of migraine with aura, familial hemiplegic migraine type 3 (FHM3). FHM3 is caused by mutations in SCN1A, encoding the voltage-gated Na+ channel NaV1.1 predominantly expressed in inhibitory interneurons. Homozygous Scn1aL1649Q knock-in mice died prematurely, whereas heterozygous mice had a normal lifespan. Heterozygous Scn1aL1649Q knock-in mice compared with WT mice displayed a significantly enhanced susceptibility to CSD. We found L1649Q to cause a gain-of-function effect with an impaired Na+-channel inactivation and increased ramp Na+ currents leading to hyperactivity of fast-spiking inhibitory interneurons. Brain slice recordings using K+-sensitive electrodes revealed an increase in extracellular K+ in the early phase of CSD in heterozygous mice, likely representing the mechanistic link between interneuron hyperactivity and CSD initiation. The neuronal phenotype and premature death of homozygous Scn1aL1649Q knock-in mice was partially rescued by GS967, a blocker of persistent Na+ currents. Collectively, our findings identify interneuron hyperactivity as a mechanism to trigger CSD.
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Affiliation(s)
- Eva Auffenberg
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany.,Institute for Stroke and Dementia Research (ISD), University Hospital, LMU Munich, Munich, Germany
| | - Ulrike Bs Hedrich
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Raffaella Barbieri
- Biophysics Institute, Consiglio Nazionale delle Ricerche (CNR), Genoa, Italy
| | - Daniela Miely
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Bernhard Groschup
- Institute for Stroke and Dementia Research (ISD), University Hospital, LMU Munich, Munich, Germany
| | - Thomas V Wuttke
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany.,Department of Neurosurgery, University of Tübingen, Tübingen, Germany
| | - Niklas Vogel
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Philipp Lührs
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Ilaria Zanardi
- Biophysics Institute, Consiglio Nazionale delle Ricerche (CNR), Genoa, Italy
| | - Sara Bertelli
- Biophysics Institute, Consiglio Nazionale delle Ricerche (CNR), Genoa, Italy
| | - Nadine Spielmann
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
| | - Valerie Gailus-Durner
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
| | - Helmut Fuchs
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
| | - Martin Hrabě de Angelis
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany.,Chair of Experimental Genetics, School of Life Science Weihenstephan, Technische Universität München, Freising, Germany.,German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Michael Pusch
- Biophysics Institute, Consiglio Nazionale delle Ricerche (CNR), Genoa, Italy
| | - Martin Dichgans
- Institute for Stroke and Dementia Research (ISD), University Hospital, LMU Munich, Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Holger Lerche
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Paola Gavazzo
- Biophysics Institute, Consiglio Nazionale delle Ricerche (CNR), Genoa, Italy
| | - Nikolaus Plesnila
- Institute for Stroke and Dementia Research (ISD), University Hospital, LMU Munich, Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Tobias Freilinger
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany.,Department of Neurology, Klinikum Passau, Passau, Germany
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121
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Chever O, Zerimech S, Scalmani P, Lemaire L, Pizzamiglio L, Loucif A, Ayrault M, Krupa M, Desroches M, Duprat F, Léna I, Cestèle S, Mantegazza M. Initiation of migraine-related cortical spreading depolarization by hyperactivity of GABAergic neurons and NaV1.1 channels. J Clin Invest 2021; 131:e142203. [PMID: 34491914 PMCID: PMC8553565 DOI: 10.1172/jci142203] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 09/02/2021] [Indexed: 01/24/2023] Open
Abstract
Spreading depolarizations (SDs) are involved in migraine, epilepsy, stroke, traumatic brain injury, and subarachnoid hemorrhage. However, the cellular origin and specific differential mechanisms are not clear. Increased glutamatergic activity is thought to be the key factor for generating cortical spreading depression (CSD), a pathological mechanism of migraine. Here, we show that acute pharmacological activation of NaV1.1 (the main Na+ channel of interneurons) or optogenetic-induced hyperactivity of GABAergic interneurons is sufficient to ignite CSD in the neocortex by spiking-generated extracellular K+ build-up. Neither GABAergic nor glutamatergic synaptic transmission were required for CSD initiation. CSD was not generated in other brain areas, suggesting that this is a neocortex-specific mechanism of CSD initiation. Gain-of-function mutations of NaV1.1 (SCN1A) cause familial hemiplegic migraine type-3 (FHM3), a subtype of migraine with aura, of which CSD is the neurophysiological correlate. Our results provide the mechanism linking NaV1.1 gain of function to CSD generation in FHM3. Thus, we reveal the key role of hyperactivity of GABAergic interneurons in a mechanism of CSD initiation, which is relevant as a pathological mechanism of Nav1.1 FHM3 mutations, and possibly also for other types of migraine and diseases in which SDs are involved.
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Affiliation(s)
- Oana Chever
- Université Côte d'Azur and.,CNRS UMR7275, Institute of Molecular and Cellular Pharmacology (IPMC), Valbonne-Sophia Antipolis, France
| | - Sarah Zerimech
- Université Côte d'Azur and.,CNRS UMR7275, Institute of Molecular and Cellular Pharmacology (IPMC), Valbonne-Sophia Antipolis, France
| | - Paolo Scalmani
- Unità Operativa VII Clinical and Experimental Epileptology, Foundation IRCCS Neurological Institute Carlo Besta, Milan, Italy
| | - Louisiane Lemaire
- Inria Sophia Antipolis Méditerranée, MathNeuro Project Team, Valbonne-Sophia Antipolis, France
| | - Lara Pizzamiglio
- Université Côte d'Azur and.,CNRS UMR7275, Institute of Molecular and Cellular Pharmacology (IPMC), Valbonne-Sophia Antipolis, France
| | - Alexandre Loucif
- Université Côte d'Azur and.,CNRS UMR7275, Institute of Molecular and Cellular Pharmacology (IPMC), Valbonne-Sophia Antipolis, France
| | - Marion Ayrault
- Université Côte d'Azur and.,CNRS UMR7275, Institute of Molecular and Cellular Pharmacology (IPMC), Valbonne-Sophia Antipolis, France
| | - Martin Krupa
- Université Côte d'Azur, Laboratoire Jean-Alexandre Dieudonné, Nice, France
| | - Mathieu Desroches
- Inria Sophia Antipolis Méditerranée, MathNeuro Project Team, Valbonne-Sophia Antipolis, France
| | - Fabrice Duprat
- Université Côte d'Azur and.,CNRS UMR7275, Institute of Molecular and Cellular Pharmacology (IPMC), Valbonne-Sophia Antipolis, France.,INSERM, Valbonne-Sophia Antipolis, France
| | - Isabelle Léna
- Université Côte d'Azur and.,CNRS UMR7275, Institute of Molecular and Cellular Pharmacology (IPMC), Valbonne-Sophia Antipolis, France
| | - Sandrine Cestèle
- Université Côte d'Azur and.,CNRS UMR7275, Institute of Molecular and Cellular Pharmacology (IPMC), Valbonne-Sophia Antipolis, France
| | - Massimo Mantegazza
- Université Côte d'Azur and.,CNRS UMR7275, Institute of Molecular and Cellular Pharmacology (IPMC), Valbonne-Sophia Antipolis, France.,INSERM, Valbonne-Sophia Antipolis, France
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Jancovski N, Baldwin T, Orford M, Li M, Jones GD, Burbano LE, Rutherford T, Reid C, Heales S, Eaton S, Petrou S. Protective effects of medium chain triglyceride diet in a mouse model of Dravet syndrome. Epilepsia 2021; 62:3131-3142. [PMID: 34713469 DOI: 10.1111/epi.17101] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 09/27/2021] [Accepted: 10/05/2021] [Indexed: 01/10/2023]
Abstract
OBJECTIVE Dravet syndrome (DS) is a severe developmental and epileptic encephalopathy with early childhood onset. Patients with DS do not respond well to antiepileptic drugs and have only a few treatment options available. Here, we evaluated the effect of medium chain triglyceride (MCT) diet therapy in a mouse model of DS. METHODS Scn1aR1407X/+ DS mice were given diets supplemented with MCTs with varying ratios of decanoic (C10) and octanoic (C8) acid or a control diet for 4 weeks. Video monitoring was performed to evaluate spontaneous convulsive seizure frequency. Susceptibility to hyperthermia-induced seizures was also examined. Medium chain fatty acids, and mitochondrial and antioxidant markers were assessed in brain homogenate. RESULTS Dietary intervention with MCTs significantly prolonged survival and reduced convulsive seizure frequency during the critical period of highest seizure occurrence in the Scn1aR1407X/+ DS mice. Moreover, MCT diet therapy showed protective effects against hyperthermia-induced seizures. We demonstrated that coadministration of C10/C8 was effective at reducing both seizures and mortality, whereas C10 alone only reduced mortality, suggesting that the ratio of C10 to C8 in the MCT is an important factor for efficacy. When C10 and C8 are supplemented at an 80:20 ratio in the diet, C10 accumulates in the brain in high enough concentrations to enhance brain energy metabolism by both stimulating mitochondrial enrichment and increasing its antioxidant status. SIGNIFICANCE The results from this study indicate that MCT diet therapy may provide therapeutic benefits in DS. Future clinical studies would elucidate whether these positive effects are mirrored in human patients.
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Affiliation(s)
- Nikola Jancovski
- Florey Institute for Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | - Tomas Baldwin
- Developmental Biology and Cancer University College London Great Ormond Street Institute of Child Health, London, UK
| | - Michael Orford
- Developmental Biology and Cancer University College London Great Ormond Street Institute of Child Health, London, UK
| | - Melody Li
- Florey Institute for Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | - Gabriel Davis Jones
- Florey Institute for Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | - Lisseth Estefania Burbano
- Florey Institute for Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | | | - Christopher Reid
- Florey Institute for Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | - Simon Heales
- Inborn Errors of Metabolism, Chemical Pathology, University College London Metabolism, Great Ormond Street for Children Hospital, Chemical Pathology, Great Ormond Street Hospital, London, UK.,Neurometabolic Unit, National Hospital, London, UK
| | - Simon Eaton
- Developmental Biology and Cancer University College London Great Ormond Street Institute of Child Health, London, UK
| | - Steven Petrou
- Florey Institute for Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
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Duba-Kiss R, Niibori Y, Hampson DR. GABAergic Gene Regulatory Elements Used in Adeno-Associated Viral Vectors. Front Neurol 2021; 12:745159. [PMID: 34671313 PMCID: PMC8521139 DOI: 10.3389/fneur.2021.745159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 09/06/2021] [Indexed: 11/13/2022] Open
Abstract
Several neurological and psychiatric disorders have been associated with impairments in GABAergic inhibitory neurons in the brain. Thus, in the current era of accelerated development of molecular medicine and biologically-based drugs, there is a need to identify gene regulatory sequences that can be utilized for selectively manipulating the expression of nucleic acids and proteins in GABAergic neurons. This is particularly important for the use of viral vectors in gene therapy. In this Mini Review, we discuss the use of various gene regulatory elements for targeting GABAergic neurons, with an emphasis on adeno-associated viral vectors, the most widely used class of viral vectors for treating brain diseases.
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Affiliation(s)
- Robert Duba-Kiss
- Department of Pharmacology and Toxicology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Yosuke Niibori
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON, Canada
| | - David R Hampson
- Department of Pharmacology and Toxicology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada.,Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON, Canada
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124
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Bagheri S, Haddadi R, Saki S, Kourosh-Arami M, Komaki A. The effect of sodium channels on neurological/neuronal disorders: A systematic review. Int J Dev Neurosci 2021; 81:669-685. [PMID: 34687079 DOI: 10.1002/jdn.10153] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 10/06/2021] [Accepted: 10/19/2021] [Indexed: 12/19/2022] Open
Abstract
Neurological and neuronal disorders are associated with structural, biochemical, or electrical abnormalities in the nervous system. Many neurological diseases have not yet been discovered. Interventions used for the treatment of these disorders include avoidance measures, lifestyle changes, physiotherapy, neurorehabilitation, pain management, medication, and surgery. In the sodium channelopathies, alterations in the structure, expression, and function of voltage-gated sodium channels (VGSCs) are considered as the causes of neurological and neuronal diseases. Online databases, including Scopus, Science Direct, Google Scholar, and PubMed were assessed for studies published between 1977 and 2020 using the keywords of review, sodium channels blocker, neurological diseases, and neuronal diseases. VGSCs consist of one α subunit and two β subunits. These subunits are known to regulate the gating kinetics, functional characteristics, and localization of the ion channel. These channels are involved in cell migration, cellular connections, neuronal pathfinding, and neurite outgrowth. Through the VGSC, the action potential is triggered and propagated in the neurons. Action potentials are physiological functions and passage of impermeable ions. The electrophysiological properties of these channels and their relationship with neurological and neuronal disorders have been identified. Subunit mutations are involved in the development of diseases, such as epilepsy, multiple sclerosis, autism, and Alzheimer's disease. Accordingly, we conducted a review of the link between VGSCs and neurological and neuronal diseases. Also, novel therapeutic targets were introduced for future drug discoveries.
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Affiliation(s)
- Shokufeh Bagheri
- Neurophysiology Research Center, Hamadan University of Medical Sciences, Hamadan, Iran.,Department of Neuroscience, School of Science and Advanced Technologies in Medicine, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Rasool Haddadi
- Department of Pharmacology, School of Pharmacy, Hamadan University of Medical Science, Hamadan, Iran
| | - Sahar Saki
- Vice-Chancellor for Research and Technology, Hamadan University of Medical Science, Hamadan, Iran
| | - Masoumeh Kourosh-Arami
- Department of Neuroscience, School of Advanced Technologies in Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Alireza Komaki
- Neurophysiology Research Center, Hamadan University of Medical Sciences, Hamadan, Iran.,Department of Neuroscience, School of Science and Advanced Technologies in Medicine, Hamadan University of Medical Sciences, Hamadan, Iran
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Huang CH, Hung PL, Fan PC, Lin KL, Hsu TR, Chou IJ, Ho CS, Chou IC, Lin WS, Lee IC, Fan HC, Chen SJ, Liang JS, Tu YF, Chang TM, Hu SC, Wong LC, Hung KL, Lee WT. Clinical spectrum and the comorbidities of Dravet syndrome in Taiwan and the possible molecular mechanisms. Sci Rep 2021; 11:20242. [PMID: 34642351 PMCID: PMC8511137 DOI: 10.1038/s41598-021-98517-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 09/03/2021] [Indexed: 11/09/2022] Open
Abstract
Dravet syndrome (DS) is an uncommon epilepsy syndrome that may negatively affect the patients and their caregivers. However, reliable and valid measures of its impact on caregivers and the characteristics of patients with DS in Taiwan are lacking. This study aimed to describe the characteristics of patients with DS and concerns of their caregivers and establish a baseline frequency of disease characteristics using a cross-sectional survey in Taiwan. We assessed the caregivers of patients with DS using an online anonymous questionnaire. The seizure frequency decreased with age, although lacking statistical significance. Vaccines show no influence on the condition of patients with DS. Our findings revealed the highest impact on the domains affecting the caregivers’ daily life, including additional household tasks, symptom observation, further medical plan, and financial issues. Caregivers also expressed concerns regarding the lack of independence/constant care, seizure control, speech/communication, and impacts on siblings because of long-term care of the patients in parents’ absence. Our findings highlight the significant effects of caring for a child with DS on the lives of their caregivers in Taiwan; these findings will help raise awareness regarding the needs of these families. Furthermore, we discussed the possible pathophysiological mechanisms of associated comorbidities.
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Affiliation(s)
- Chia-Hsuan Huang
- Division of Pediatric Neurology, Department of Pediatrics, National Taiwan University Hospital Yunlin Branch, Yunlin County, Taiwan
| | - Pi-Lien Hung
- Department of Pediatric Neurology, Chang Gung Memorial Hospital-Kaohsiung, Kaohsiung, Taiwan
| | - Pi-Chuan Fan
- Department of Pediatrics, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan
| | - Kuang-Lin Lin
- Division of Pediatric Neurology, Chang Gung Children's Hospital and Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taoyuan, Taiwan
| | - Ting-Rong Hsu
- Department of Pediatrics, Taipei Veterans General Hospital, Taipei, Taiwan
| | - I-Jun Chou
- Division of Pediatric Neurology, Chang Gung Children's Hospital and Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taoyuan, Taiwan
| | - Che-Sheng Ho
- Department of Pediatrics, Mackay Memorial Hospital, Taipei, Taiwan
| | - I-Ching Chou
- Division of Pediatrics Neurology, China Medical University Children's Hospital, Taichung, Taiwan
| | - Wei-Sheng Lin
- Department of Pediatrics, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Inn-Chi Lee
- Institute of Medicine, School of Medicine, Chung Shan Medical University, Taichung, Taiwan
| | - Hueng-Chuen Fan
- Department of Pediatrics, Tungs' Taichung Metroharbor Hospital, Taichung, Taiwan
| | - Shyi-Jou Chen
- Department of Pediatrics, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Jao-Shwann Liang
- Department of Pediatrics, Far Eastern Memorial Hospital, New Taipei City, Taiwan
| | - Yi-Fang Tu
- Department of Pediatrics, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Tung-Ming Chang
- Department of Pediatric Neurology, Changhua Christian Children's Hospital, Changhua, Taiwan
| | - Su-Ching Hu
- Department of Pediatrics, Cathay General Hospital, Taipei, Taiwan
| | - Lee-Chin Wong
- Department of Pediatrics, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan.,Department of Pediatrics, Cathay General Hospital, Taipei, Taiwan
| | - Kun-Long Hung
- Department of Pediatrics, Fu-Jen Catholic University Hospital, Fu-Jen Catholic University, New Taipei City, Taiwan
| | - Wang-Tso Lee
- Department of Pediatrics, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan. .,Department of Pediatric Neurology, National Taiwan University Children's Hospital, 8, Chung-Shan South Road, Taipei, 100, Taiwan.
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Crotts MS, Kim Y, Bravo E, Richerson GB, Teran FA. A ketogenic diet protects DBA/1 and Scn1a R1407X/+ mice against seizure-induced respiratory arrest independent of ketosis. Epilepsy Behav 2021; 124:108334. [PMID: 34600281 PMCID: PMC8960470 DOI: 10.1016/j.yebeh.2021.108334] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 09/02/2021] [Accepted: 09/07/2021] [Indexed: 10/20/2022]
Abstract
Patients with uncontrolled epilepsy have a high risk of sudden unexpected death in epilepsy (SUDEP). Seizure-induced respiratory arrest (S-IRA) is thought to be the determining cause of death in many cases of SUDEP. The goal of the present study was to use Scn1aR1407X/+ (Dravet Syndrome, DS) and DBA/1 mice to determine: (1) the effect of a ketogenic diet (KD) on S-IRA and (2) the relationship between serum ketones and the protective effect of a KD. Ketogenic diet treatment significantly decreased spontaneous seizure-induced mortality in DS mice compared to control (8% vs 39%, p = 0.0021). This protective effect was not abolished when ketosis was prevented by supplementing the KD with glucose (10% mortality, p = 0.0007). In DBA/1 mice, the latency to onset of S-IRA due to audiogenic seizures was delayed from 7.6 to 20.8 seconds by a KD on treatment day (TD) 7 compared to control (p < 0.0001), an effect that was reversed on TD14 when mice were crossed over to a control diet on TD7. β-Hydroxybutyrate (BHB) levels were significantly decreased in DBA/1 mice on a KD supplemented with glucose (p = 0.0038), but the protective effect was maintained. Our findings show that a KD decreases SUDEP in DS mice and increases the latency to audiogenic S-IRA in DBA/1 mice. In both mouse models, a KD was protective against S-IRA. This effect may be due in part to specific dietary components rather than generation of ketone bodies.
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Affiliation(s)
- Megan S Crotts
- Department of Neurology, University of Iowa, Iowa City, IA 52242, United States; Iowa Neuroscience Institute, University of Iowa, Iowa City, IA 52242, United States
| | - YuJaung Kim
- Department of Neurology, University of Iowa, Iowa City, IA 52242, United States
| | - Eduardo Bravo
- Department of Neurology, University of Iowa, Iowa City, IA 52242, United States
| | - George B Richerson
- Department of Neurology, University of Iowa, Iowa City, IA 52242, United States; Iowa Neuroscience Institute, University of Iowa, Iowa City, IA 52242, United States; Department of Molecular Physiology & Biophysics, University of Iowa, Iowa City, IA 52242, United States; Neurology, Veterans Affairs Medical Center, Iowa City, IA 52242, United States
| | - Frida A Teran
- Department of Neurology, University of Iowa, Iowa City, IA 52242, United States; Iowa Neuroscience Institute, University of Iowa, Iowa City, IA 52242, United States; Medical Scientist Training Program, University of Iowa, Iowa City, IA 52242, United States.
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127
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Hawkins NA, Jurado M, Thaxton TT, Duarte SE, Barse L, Tatsukawa T, Yamakawa K, Nishi T, Kondo S, Miyamoto M, Abrahams BS, During MJ, Kearney JA. Soticlestat, a novel cholesterol 24-hydroxylase inhibitor, reduces seizures and premature death in Dravet syndrome mice. Epilepsia 2021; 62:2845-2857. [PMID: 34510432 PMCID: PMC9291096 DOI: 10.1111/epi.17062] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 08/23/2021] [Accepted: 08/23/2021] [Indexed: 02/06/2023]
Abstract
OBJECTIVE Dravet syndrome is a severe developmental and epileptic encephalopathy (DEE) most often caused by de novo pathogenic variants in SCN1A. Individuals with Dravet syndrome rarely achieve seizure control and have significantly elevated risk for sudden unexplained death in epilepsy (SUDEP). Heterozygous deletion of Scn1a in mice (Scn1a+/- ) recapitulates several core phenotypes, including temperature-dependent and spontaneous seizures, SUDEP, and behavioral abnormalities. Furthermore, Scn1a+/- mice exhibit a similar clinical response to standard anticonvulsants. Cholesterol 24-hydroxlase (CH24H) is a brain-specific enzyme responsible for cholesterol catabolism. Recent research has indicated the therapeutic potential of CH24H inhibition for diseases associated with neural excitation, including seizures. METHODS In this study, the novel compound soticlestat, a CH24H inhibitor, was administered to Scn1a+/- mice to investigate its ability to improve Dravet-like phenotypes in this preclinical model. RESULTS Soticlestat treatment reduced seizure burden, protected against hyperthermia-induced seizures, and completely prevented SUDEP in Scn1a+/- mice. Video-electroencephalography (EEG) analysis confirmed the ability of soticlestat to reduce occurrence of electroclinical seizures. SIGNIFICANCE This study demonstrates that soticlestat-mediated inhibition of CH24H provides therapeutic benefit for the treatment of Dravet syndrome in mice and has the potential for treatment of DEEs.
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Affiliation(s)
- Nicole A Hawkins
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Manuel Jurado
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Tyler T Thaxton
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Samantha E Duarte
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Levi Barse
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Tetsuya Tatsukawa
- Laboratory for Neurogenetics, RIKEN Brain Science Institute, Wako, Japan
| | - Kazuhiro Yamakawa
- Laboratory for Neurogenetics, RIKEN Brain Science Institute, Wako, Japan
| | - Toshiya Nishi
- Neuroscience Drug Discovery Unit, Takeda Pharmaceutical Ltd, Fujisawa, Japan
| | - Shinichi Kondo
- Neuroscience Drug Discovery Unit, Takeda Pharmaceutical Ltd, Fujisawa, Japan
| | - Maki Miyamoto
- Neuroscience Drug Discovery Unit, Takeda Pharmaceutical Ltd, Fujisawa, Japan
| | | | | | - Jennifer A Kearney
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
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128
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Seizure Phenotype and Underlying Cellular Defects in Drosophila Knock-In Models of DS (R1648C) and GEFS+ (R1648H) SCN1A Epilepsy. eNeuro 2021; 8:ENEURO.0002-21.2021. [PMID: 34475263 PMCID: PMC8454921 DOI: 10.1523/eneuro.0002-21.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2021] [Revised: 08/05/2021] [Accepted: 08/14/2021] [Indexed: 11/21/2022] Open
Abstract
Mutations in the voltage-gated sodium channel gene SCN1A are associated with human epilepsy disorders, but how most of these mutations alter channel properties and result in seizures is unknown. This study focuses on two different mutations occurring at one position within SCN1A. R1648C (R-C) is associated with the severe disorder Dravet syndrome, and R1648H (R-H), with the milder disorder GEFS+. To explore how these different mutations contribute to distinct seizure disorders, Drosophila lines with the R-C or R-H mutation, or R1648R (R-R) control substitution in the fly sodium channel gene para were generated by CRISPR-Cas9 gene editing. The R-C and R-H mutations are homozygous lethal. Animals heterozygous for R-C or R-H mutations displayed reduced life spans and spontaneous and temperature-induced seizures not observed in R-R controls. Electrophysiological recordings from adult GABAergic neurons in R-C and R-H mutants revealed the appearance of sustained neuronal depolarizations and altered firing frequency that were exacerbated at elevated temperature. The only significant change observed in underlying sodium currents in both R-C and R-H mutants was a hyperpolarized deactivation threshold at room and elevated temperature compared with R-R controls. Since this change is constitutive, it is likely to interact with heat-induced changes in other cellular properties to result in the heat-induced increase in sustained depolarizations and seizure activity. Further, the similarity of the behavioral and cellular phenotypes in the R-C and R-H fly lines, suggests that disease symptoms of different severity associated with these mutations in humans could be due in large part to differences in genetic background.
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129
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Porciúncula LO, Goto-Silva L, Ledur PF, Rehen SK. The Age of Brain Organoids: Tailoring Cell Identity and Functionality for Normal Brain Development and Disease Modeling. Front Neurosci 2021. [DOI: 10.3389/fnins.2021.674563
expr 918028134 + 817050540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023] Open
Abstract
Over the past years, brain development has been investigated in rodent models, which were particularly relevant to establish the role of specific genes in this process. However, the cytoarchitectonic features, which determine neuronal network formation complexity, are unique to humans. This implies that the developmental program of the human brain and neurological disorders can only partly be reproduced in rodents. Advancement in the study of the human brain surged with cultures of human brain tissue in the lab, generated from induced pluripotent cells reprogrammed from human somatic tissue. These cultures, termed brain organoids, offer an invaluable model for the study of the human brain. Brain organoids reproduce the cytoarchitecture of the cortex and can develop multiple brain regions and cell types. Integration of functional activity of neural cells within brain organoids with genetic, cellular, and morphological data in a comprehensive model for human development and disease is key to advance in the field. Because the functional activity of neural cells within brain organoids relies on cell repertoire and time in culture, here, we review data supporting the gradual formation of complex neural networks in light of cell maturity within brain organoids. In this context, we discuss how the technology behind brain organoids brought advances in understanding neurodevelopmental, pathogen-induced, and neurodegenerative diseases.
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130
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Porciúncula LO, Goto-Silva L, Ledur PF, Rehen SK. The Age of Brain Organoids: Tailoring Cell Identity and Functionality for Normal Brain Development and Disease Modeling. Front Neurosci 2021; 15:674563. [PMID: 34483818 PMCID: PMC8414411 DOI: 10.3389/fnins.2021.674563] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 07/19/2021] [Indexed: 12/15/2022] Open
Abstract
Over the past years, brain development has been investigated in rodent models, which were particularly relevant to establish the role of specific genes in this process. However, the cytoarchitectonic features, which determine neuronal network formation complexity, are unique to humans. This implies that the developmental program of the human brain and neurological disorders can only partly be reproduced in rodents. Advancement in the study of the human brain surged with cultures of human brain tissue in the lab, generated from induced pluripotent cells reprogrammed from human somatic tissue. These cultures, termed brain organoids, offer an invaluable model for the study of the human brain. Brain organoids reproduce the cytoarchitecture of the cortex and can develop multiple brain regions and cell types. Integration of functional activity of neural cells within brain organoids with genetic, cellular, and morphological data in a comprehensive model for human development and disease is key to advance in the field. Because the functional activity of neural cells within brain organoids relies on cell repertoire and time in culture, here, we review data supporting the gradual formation of complex neural networks in light of cell maturity within brain organoids. In this context, we discuss how the technology behind brain organoids brought advances in understanding neurodevelopmental, pathogen-induced, and neurodegenerative diseases.
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Affiliation(s)
- Lisiane O. Porciúncula
- Department of Biochemistry, Program of Biological Sciences - Biochemistry, Institute of Health and Basic Sciences, Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
| | - Livia Goto-Silva
- D'Or Institute for Research and Education (IDOR), Rio de Janeiro, Brazil
| | - Pitia F. Ledur
- D'Or Institute for Research and Education (IDOR), Rio de Janeiro, Brazil
| | - Stevens K. Rehen
- D'Or Institute for Research and Education (IDOR), Rio de Janeiro, Brazil
- Department of Genetics, Institute of Biology, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
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131
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Arribas-Blázquez M, Piniella D, Olivos-Oré LA, Bartolomé-Martín D, Leite C, Giménez C, Artalejo AR, Zafra F. Regulation of the voltage-dependent sodium channel Na V1.1 by AKT1. Neuropharmacology 2021; 197:108745. [PMID: 34375627 DOI: 10.1016/j.neuropharm.2021.108745] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 07/09/2021] [Accepted: 08/02/2021] [Indexed: 11/28/2022]
Abstract
The voltage-sensitive sodium channel NaV1.1 plays a critical role in regulating excitability of GABAergic neurons and mutations in the corresponding gene are associated to Dravet syndrome and other forms of epilepsy. The activity of this channel is regulated by several protein kinases. To identify novel regulatory kinases we screened a library of activated kinases and we found that AKT1 was able to directly phosphorylate NaV1.1. In vitro kinase assays revealed that the phosphorylation site was located in the C-terminal part of the large intracellular loop connecting domains I and II of NaV1.1, a region that is known to be targeted by other kinases like PKA and PKC. Electrophysiological recordings revealed that activated AKT1 strongly reduced peak Na+ currents and displaced the inactivation curve to more negative potentials in HEK-293 cell stably expressing NaV1.1. These alterations in current amplitude and steady-state inactivation were mimicked by SC79, a specific activator of AKT1, and largely reverted by triciribine, a selective inhibitor. Neurons expressing endogenous NaV1.1 in primary cultures were identified by expressing a fluorescent protein under the NaV1.1 promoter. There, we also observed a strong decrease in the current amplitude after addition of SC79, but small effects on the inactivation parameters. Altogether, we propose a novel mechanism that might regulate the excitability of neural networks in response to AKT1, a kinase that plays a pivotal role under physiological and pathological conditions, including epileptogenesis.
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Affiliation(s)
- Marina Arribas-Blázquez
- Centro de Biología Molecular Severo Ochoa, Facultad de Ciencias, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Madrid, Spain; Department of Pharmacology and Toxicology, Veterinary Faculty, Universidad Complutense de Madrid, 28040, Madrid, Spain
| | - Dolores Piniella
- Centro de Biología Molecular Severo Ochoa, Facultad de Ciencias, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Madrid, Spain; IdiPAZ, Instituto de Salud Carlos III, Madrid, Spain
| | - Luis A Olivos-Oré
- Department of Pharmacology and Toxicology, Veterinary Faculty, Universidad Complutense de Madrid, 28040, Madrid, Spain; Instituto Universitario de Investigación en Neuroquímica, Universidad Complutense de Madrid, 28040, Madrid, Spain
| | - David Bartolomé-Martín
- Centro de Biología Molecular Severo Ochoa, Facultad de Ciencias, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Madrid, Spain; IdiPAZ, Instituto de Salud Carlos III, Madrid, Spain
| | - Cristiana Leite
- Centro de Biología Molecular Severo Ochoa, Facultad de Ciencias, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Madrid, Spain
| | - Cecilio Giménez
- Centro de Biología Molecular Severo Ochoa, Facultad de Ciencias, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Madrid, Spain; IdiPAZ, Instituto de Salud Carlos III, Madrid, Spain
| | - Antonio R Artalejo
- Department of Pharmacology and Toxicology, Veterinary Faculty, Universidad Complutense de Madrid, 28040, Madrid, Spain; Instituto Universitario de Investigación en Neuroquímica, Universidad Complutense de Madrid, 28040, Madrid, Spain
| | - Francisco Zafra
- Centro de Biología Molecular Severo Ochoa, Facultad de Ciencias, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Madrid, Spain; IdiPAZ, Instituto de Salud Carlos III, Madrid, Spain.
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132
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Hill SF, Meisler MH. Antisense Oligonucleotide Therapy for Neurodevelopmental Disorders. Dev Neurosci 2021; 43:247-252. [PMID: 34412058 PMCID: PMC8440367 DOI: 10.1159/000517686] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 06/01/2021] [Indexed: 12/13/2022] Open
Abstract
Antisense oligonucleotides (ASOs) are short oligonucleotides that can modify gene expression and mRNA splicing in the nervous system. The FDA has approved ASOs for treatment of ten genetic disorders, with many applications currently in the pipeline. We describe the molecular mechanisms of ASO treatment for four neurodevelopmental and neuromuscular disorders. The ASO nusinersen is a general treatment for mutations of SMN1 in spinal muscular atrophy that corrects the splicing defect in the SMN2 gene. Milasen is a patient-specific ASO that rescues splicing of CNL7 in Batten's disease. STK-001 is an ASO that increases expression of the sodium channel gene SCN1A by exclusion of a poison exon. An ASO that reduces the abundance of the SCN8A mRNA is therapeutic in mouse models of developmental and epileptic encephalopathy. These examples demonstrate the variety of mechanisms and range of applications of ASOs for treatment of neurodevelopmental disorders.
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Affiliation(s)
- Sophie F Hill
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, Michigan, USA
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan, USA
| | - Miriam H Meisler
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, Michigan, USA
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan, USA
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133
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Spratt PWE, Alexander RPD, Ben-Shalom R, Sahagun A, Kyoung H, Keeshen CM, Sanders SJ, Bender KJ. Paradoxical hyperexcitability from Na V1.2 sodium channel loss in neocortical pyramidal cells. Cell Rep 2021; 36:109483. [PMID: 34348157 PMCID: PMC8719649 DOI: 10.1016/j.celrep.2021.109483] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 05/17/2021] [Accepted: 07/13/2021] [Indexed: 12/17/2022] Open
Abstract
Loss-of-function variants in the gene SCN2A, which encodes the sodium channel NaV1.2, are strongly associated with autism spectrum disorder and intellectual disability. An estimated 20%-30% of children with these variants also suffer from epilepsy, with altered neuronal activity originating in neocortex, a region where NaV1.2 channels are expressed predominantly in excitatory pyramidal cells. This is paradoxical, as sodium channel loss in excitatory cells would be expected to dampen neocortical activity rather than promote seizure. Here, we examined pyramidal neurons lacking NaV1.2 channels and found that they were intrinsically hyperexcitable, firing high-frequency bursts of action potentials (APs) despite decrements in AP size and speed. Compartmental modeling and dynamic-clamp recordings revealed that NaV1.2 loss prevented potassium channels from properly repolarizing neurons between APs, increasing overall excitability by allowing neurons to reach threshold for subsequent APs more rapidly. This cell-intrinsic mechanism may, therefore, account for why SCN2A loss-of-function can paradoxically promote seizure.
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Affiliation(s)
- Perry W E Spratt
- Neuroscience Graduate Program, Kavli Institute for Fundamental Neuroscience, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA
| | - Ryan P D Alexander
- Department of Neurology, Kavli Institute for Fundamental Neuroscience, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA
| | - Roy Ben-Shalom
- Department of Neurology, Kavli Institute for Fundamental Neuroscience, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA
| | - Atehsa Sahagun
- Department of Neurology, Kavli Institute for Fundamental Neuroscience, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA
| | - Henry Kyoung
- Department of Neurology, Kavli Institute for Fundamental Neuroscience, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA
| | - Caroline M Keeshen
- Department of Neurology, Kavli Institute for Fundamental Neuroscience, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA
| | - Stephan J Sanders
- Department of Psychiatry, Kavli Institute for Fundamental Neuroscience, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA
| | - Kevin J Bender
- Neuroscience Graduate Program, Kavli Institute for Fundamental Neuroscience, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA; Department of Neurology, Kavli Institute for Fundamental Neuroscience, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA.
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134
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Platholi J, Hemmings HC. Effects of general anesthetics on synaptic transmission and plasticity. Curr Neuropharmacol 2021; 20:27-54. [PMID: 34344292 PMCID: PMC9199550 DOI: 10.2174/1570159x19666210803105232] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 07/26/2021] [Accepted: 08/02/2021] [Indexed: 11/22/2022] Open
Abstract
General anesthetics depress excitatory and/or enhance inhibitory synaptic transmission principally by modulating the function of glutamatergic or GABAergic synapses, respectively, with relative anesthetic agent-specific mechanisms. Synaptic signaling proteins, including ligand- and voltage-gated ion channels, are targeted by general anesthetics to modulate various synaptic mechanisms, including presynaptic neurotransmitter release, postsynaptic receptor signaling, and dendritic spine dynamics to produce their characteristic acute neurophysiological effects. As synaptic structure and plasticity mediate higher-order functions such as learning and memory, long-term synaptic dysfunction following anesthesia may lead to undesirable neurocognitive consequences depending on the specific anesthetic agent and the vulnerability of the population. Here we review the cellular and molecular mechanisms of transient and persistent general anesthetic alterations of synaptic transmission and plasticity.
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Affiliation(s)
- Jimcy Platholi
- Cornell University Joan and Sanford I Weill Medical College Ringgold standard institution - Anesthesiology New York, New York. United States
| | - Hugh C Hemmings
- Cornell University Joan and Sanford I Weill Medical College Ringgold standard institution - Anesthesiology New York, New York. United States
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135
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Lemaire L, Desroches M, Krupa M, Pizzamiglio L, Scalmani P, Mantegazza M. Modeling NaV1.1/SCN1A sodium channel mutations in a microcircuit with realistic ion concentration dynamics suggests differential GABAergic mechanisms leading to hyperexcitability in epilepsy and hemiplegic migraine. PLoS Comput Biol 2021; 17:e1009239. [PMID: 34314446 PMCID: PMC8345895 DOI: 10.1371/journal.pcbi.1009239] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Revised: 08/06/2021] [Accepted: 07/02/2021] [Indexed: 11/19/2022] Open
Abstract
Loss of function mutations of SCN1A, the gene coding for the voltage-gated sodium channel NaV1.1, cause different types of epilepsy, whereas gain of function mutations cause sporadic and familial hemiplegic migraine type 3 (FHM-3). However, it is not clear yet how these opposite effects can induce paroxysmal pathological activities involving neuronal networks’ hyperexcitability that are specific of epilepsy (seizures) or migraine (cortical spreading depolarization, CSD). To better understand differential mechanisms leading to the initiation of these pathological activities, we used a two-neuron conductance-based model of interconnected GABAergic and pyramidal glutamatergic neurons, in which we incorporated ionic concentration dynamics in both neurons. We modeled FHM-3 mutations by increasing the persistent sodium current in the interneuron and epileptogenic mutations by decreasing the sodium conductance in the interneuron. Therefore, we studied both FHM-3 and epileptogenic mutations within the same framework, modifying only two parameters. In our model, the key effect of gain of function FHM-3 mutations is ion fluxes modification at each action potential (in particular the larger activation of voltage-gated potassium channels induced by the NaV1.1 gain of function), and the resulting CSD-triggering extracellular potassium accumulation, which is not caused only by modifications of firing frequency. Loss of function epileptogenic mutations, on the other hand, increase GABAergic neurons’ susceptibility to depolarization block, without major modifications of firing frequency before it. Our modeling results connect qualitatively to experimental data: potassium accumulation in the case of FHM-3 mutations and facilitated depolarization block of the GABAergic neuron in the case of epileptogenic mutations. Both these effects can lead to pyramidal neuron hyperexcitability, inducing in the migraine condition depolarization block of both the GABAergic and the pyramidal neuron. Overall, our findings suggest different mechanisms of network hyperexcitability for migraine and epileptogenic NaV1.1 mutations, implying that the modifications of firing frequency may not be the only relevant pathological mechanism. The voltage-gated sodium channel NaV1.1 is a major target of human mutations implicated in different pathologies. In particular, mutations identified in certain types of epilepsy cause loss of function of the channel, whereas mutations identified in certain types of migraine (in which spreading depolarizations of the cortical circuits of the brain are involved) cause instead gain of function. Here, we study dysfunctions induced by these differential effects in a two-neuron (GABAergic and pyramidal) conductance-based model with dynamic ion concentrations. We obtain results that can be related to experimental findings in both situations. Namely, extracellular potassium accumulation induced by the activity of the GABAergic neuron in the case of CSD, and higher propensity of the GABAergic neuron to depolarization block in the epileptogenic scenario, without significant modifications of its firing frequency prior to it. Both scenarios can induce hyperexcitability of the pyramidal neuron, leading in the migraine condition to depolarization block of both the GABAergic and the pyramidal neuron. Our results are successfully confronted to experimental data and suggest that modification of firing frequency is not the only key mechanism in these pathologies of neuronal excitability.
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Affiliation(s)
- Louisiane Lemaire
- Inria Sophia Antipolis Méditerranée Research Centre, MathNeuro Team, Valbonne-Sophia Antipolis, France
- Université Côte d’Azur, Nice, France
- * E-mail: (LL); (MM)
| | - Mathieu Desroches
- Inria Sophia Antipolis Méditerranée Research Centre, MathNeuro Team, Valbonne-Sophia Antipolis, France
- Université Côte d’Azur, Nice, France
| | - Martin Krupa
- Inria Sophia Antipolis Méditerranée Research Centre, MathNeuro Team, Valbonne-Sophia Antipolis, France
- Université Côte d’Azur, Laboratoire Jean-Alexandre Dieudonné, Nice, France
| | - Lara Pizzamiglio
- Université Côte d’Azur, Institute of Molecular and Cellular Pharmacology (IPMC), Valbonne-Sophia Antipolis, France
- CNRS UMR7275, Institute of Molecular and Cellular Pharmacology (IPMC), Valbonne-Sophia Antipolis, France
| | - Paolo Scalmani
- U.O. VII Clinical and Experimental Epileptology, Foundation IRCCS Neurological Institute Carlo Besta, Milan, Italy
| | - Massimo Mantegazza
- Université Côte d’Azur, Institute of Molecular and Cellular Pharmacology (IPMC), Valbonne-Sophia Antipolis, France
- CNRS UMR7275, Institute of Molecular and Cellular Pharmacology (IPMC), Valbonne-Sophia Antipolis, France
- Inserm, Valbonne-Sophia Antipolis, France
- * E-mail: (LL); (MM)
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136
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Ho SY, Lin L, Chen IC, Tsai CW, Chang FC, Liou HH. Perampanel Reduces Hyperthermia-Induced Seizures in Dravet Syndrome Mouse Model. Front Pharmacol 2021; 12:682767. [PMID: 34335252 PMCID: PMC8317459 DOI: 10.3389/fphar.2021.682767] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 06/21/2021] [Indexed: 11/13/2022] Open
Abstract
Treatment options for Dravet syndrome are limited. The aim of this study was to evaluate the antiepileptic effect of the AMPA receptor antagonist perampanel (PER) on a mouse model of Dravet syndrome (Scn1aE1099X/+). We report here that the PER (2 mg/kg) treatment inhibited the spontaneous recurrent seizures and attenuated epileptic activity in Scn1aE1099X/+ mice. In the hyperthermia-induced seizure experiment, PER clearly increased temperature tolerance and significantly ameliorated seizure frequency and discharge duration. PER also demonstrated antiepileptic effects in a cross-over study and a synergistic effect for attenuating heat-induced seizure when given in combination with stiripentol or valproic acid. The results showed that PER effectively decreased the occurrence of spontaneous recurrent seizures and showed significant therapeutic potential for hyperthermia-induced seizures with regard to both susceptibility and severity in a Dravet syndrome mouse model. Potential therapeutic effects of PER for treatment of Dravet syndrome were demonstrated.
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Affiliation(s)
- Shih-Yin Ho
- Department of Neurology, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan.,Department and Graduate Institute of Pharmacology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Li Lin
- Department and Graduate Institute of Pharmacology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - I-Chun Chen
- Department and Graduate Institute of Pharmacology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Che-Wen Tsai
- Department and Graduate Institute of Pharmacology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Fang-Chia Chang
- Department of Veterinary Medicine, School of Veterinary Medicine, National Taiwan University, Taipei, Taiwan
| | - Horng-Huei Liou
- Department of Neurology, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan.,Department and Graduate Institute of Pharmacology, College of Medicine, National Taiwan University, Taipei, Taiwan.,National Taiwan University Hospital Yunlin Branch, Douliu, Taiwan
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137
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Abstract
Genetic testing has yielded major advances in our understanding of the causes of epilepsy. Seizures remain resistant to treatment in a significant proportion of cases, particularly in severe, childhood-onset epilepsy, the patient population in which an underlying causative genetic variant is most likely to be identified. A genetic diagnosis can be explanatory as to etiology, and, in some cases, might suggest a therapeutic approach; yet, a clear path from genetic diagnosis to treatment remains unclear in most cases. Here, we discuss theoretical considerations behind the attempted use of small molecules for the treatment of genetic epilepsies, which is but one among various approaches currently under development. We explore a few salient examples and consider the future of the small molecule approach for genetic epilepsies. We conclude that significant additional work is required to understand how genetic variation leads to dysfunction of epilepsy-associated protein targets, and how this impacts the function of diverse subtypes of neurons embedded within distributed brain circuits to yield epilepsy and epilepsy-associated comorbidities. A syndrome- or even variant-specific approach may be required to achieve progress. Advances in the field will require improved methods for large-scale target validation, compound identification and optimization, and the development of accurate model systems that reflect the core features of human epilepsy syndromes, as well as novel approaches towards clinical trials of such compounds in small rare disease cohorts.
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Affiliation(s)
- Ethan M Goldberg
- Department of Pediatrics, Division of Neurology, Abramson Research Center, The Epilepsy Neurogenetics Initiative, The Children's Hospital of Philadelphia, Abramson Research Center Room 502A, 19104, Philadelphia, PA, USA.
- Departments of Neurology and Neuroscience, The University of Pennsylvania Perelman School of Medicine, 19104, Philadelphia, PA, USA.
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138
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Moretti R, Arnaud L, Bouteiller D, Trouillard O, Moreau P, Buratti J, Rastetter A, Keren B, Des Portes V, Toulouse J, Gourfinkel-An I, Leguern E, Depienne C, Mignot C, Nava C. SCN1A-related epilepsy with recessive inheritance: Two further families. Eur J Paediatr Neurol 2021; 33:121-124. [PMID: 34174751 DOI: 10.1016/j.ejpn.2021.05.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 04/29/2021] [Accepted: 05/31/2021] [Indexed: 11/19/2022]
Abstract
BACKGROUND Variants in SCN1A gene, encoding the voltage-gated sodium channel Nav1.1, are associated with distinct epilepsy syndromes ranging from the relatively benign genetic epilepsy with febrile seizures plus (GEFS+) to Dravet syndrome, a severe developmental and epileptic encephalopathy (DEE). Most SCN1A pathogenic variants are heterozygous changes inherited in a dominant or de novo inheritance and many cause a loss-of-function of one allele. To date, recessive inheritance has been suggested in only two families with affected children harboring homozygous SCN1A missense variants while their heterozygous parents were asymptomatic. The aim of this report is to describe two additional families in which affected individuals have biallelic SCN1A variants possibly explaining their phenotype. METHODS AND RESULTS We report two novel homozygous SCN1A missense variants in two patients from related parents. Both patients had fever-sensitive epilepsy beginning in the first months of life, followed by afebrile seizures, without severe cognitive impairment. Parents were asymptomatic. Next generation sequencing excluded a pathogenic variant in other genes involved in DEE. Estimation of pathogenicity scores by in-silico tools suggests that the impact of these SCN1A variants is less damaging than that of dominant pathogenic variants. CONCLUSION This study provides additional evidence that homozygous variants in SCN1A can cause GEFS+. This recessive inheritance would imply that hypomorphic variants may not necessarily cause epilepsy at the heterozygous state but may decrease the seizure threshold when combined.
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Affiliation(s)
- Raffaella Moretti
- APHP.Sorbonne Université, Département de Physiologie, Hôpital Trousseau, Paris, France
| | - Lionel Arnaud
- APHP.Sorbonne Université, Département de Génétique, Groupe Hospitalier Pitié Salpêtrière, Paris, France
| | - Delphine Bouteiller
- Sorbonne Université, Institut du Cerveau, ICM, Inserm U1127, CNRS UMR 7225, Paris, France
| | - Oriane Trouillard
- APHP.Sorbonne Université, Département de Génétique, Groupe Hospitalier Pitié Salpêtrière, Paris, France; Sorbonne Université, Institut du Cerveau, ICM, Inserm U1127, CNRS UMR 7225, Paris, France
| | - Patricia Moreau
- APHP.Sorbonne Université, Département de Génétique, Groupe Hospitalier Pitié Salpêtrière, Paris, France
| | - Julien Buratti
- APHP.Sorbonne Université, Département de Génétique, Groupe Hospitalier Pitié Salpêtrière, Paris, France
| | - Agnès Rastetter
- Sorbonne Université, Institut du Cerveau, ICM, Inserm U1127, CNRS UMR 7225, Paris, France
| | - Boris Keren
- APHP.Sorbonne Université, Département de Génétique, Groupe Hospitalier Pitié Salpêtrière, Paris, France
| | - Vincent Des Portes
- Reference Center for Rare Epilepsies CRéER, Lyon University Hospital, F-69677, Bron, France; University Lyon 1, F-69008, Lyon, France
| | - Joseph Toulouse
- Reference Center for Rare Epilepsies CRéER, Lyon University Hospital, F-69677, Bron, France
| | - Isabelle Gourfinkel-An
- APHP.Sorbonne Université, Département de Neurologie, Centre de Référence des Épilepsies Rares, Groupe Hospitalier Pitié Salpêtrière, Paris, France
| | - Eric Leguern
- APHP.Sorbonne Université, Département de Génétique, Groupe Hospitalier Pitié Salpêtrière, Paris, France; Sorbonne Université, Institut du Cerveau, ICM, Inserm U1127, CNRS UMR 7225, Paris, France
| | - Christel Depienne
- Sorbonne Université, Institut du Cerveau, ICM, Inserm U1127, CNRS UMR 7225, Paris, France; Institute of Human Genetics, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Cyril Mignot
- APHP.Sorbonne Université, Département de Génétique, Groupe Hospitalier Pitié Salpêtrière, Paris, France; Sorbonne Université, Institut du Cerveau, ICM, Inserm U1127, CNRS UMR 7225, Paris, France; Centre de Référence Déficiences Intellectuelles de Causes Rares, GH Pitié-Salpêtrière, Paris, France
| | - Caroline Nava
- APHP.Sorbonne Université, Département de Génétique, Groupe Hospitalier Pitié Salpêtrière, Paris, France; Sorbonne Université, Institut du Cerveau, ICM, Inserm U1127, CNRS UMR 7225, Paris, France.
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139
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Isom LL, Knupp KG. Dravet Syndrome: Novel Approaches for the Most Common Genetic Epilepsy. Neurotherapeutics 2021; 18:1524-1534. [PMID: 34378168 PMCID: PMC8608987 DOI: 10.1007/s13311-021-01095-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/21/2021] [Indexed: 02/04/2023] Open
Abstract
Dravet syndrome (DS) is a severe developmental and epileptic encephalopathy that is mainly associated with variants in SCN1A. While drug-resistant epilepsy is the most notable feature of this syndrome, numerous symptoms are present that have significant impact on patients' quality of life. In spite of novel, third-generation anti-seizure treatment options becoming available over the last several years, seizure freedom is often not attained and non-seizure symptoms remain. Precision medicine now offers realistic hope for seizure freedom in DS patients, with several approaches demonstrating preclinical success. Therapeutic approaches such as antisense oligonucleotides (ASO) and adeno-associated virus (AAV)-delivered gene modulation have expanded the potential treatment options for DS, with some of these approaches now transitioning to clinical trials. Several of these treatments may risk the exacerbation of gain-of-function variants and may not be reversible, therefore emphasizing the need for functional testing of new pathogenic variants. The current absence of treatments that address the overall disease, in addition to seizures, exposes the urgent need for reliable, valid measures of the entire complement of symptoms as outcome measures to truly know the impact of treatments on DS. Additionally, with so many treatment options on the horizon, there will be a need to understand how to select appropriate patients for each treatment, whether treatments are complementary or adverse to each other, and long-term risks of the treatment. Nevertheless, precision therapeutics hold tremendous potential to provide long-lasting seizure freedom and even complete cures for this devastating disease.
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Affiliation(s)
- Lori L Isom
- Department of Pharmacology, Department of Neurology, Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, 48109-5632, USA.
| | - Kelly G Knupp
- Department of Pediatrics and Neurology, University of Colorado, Anschutz Medical Campus, Aurora, CO, 80045, USA.
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140
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Shcheglovitov A, Peterson RT. Screening Platforms for Genetic Epilepsies-Zebrafish, iPSC-Derived Neurons, and Organoids. Neurotherapeutics 2021; 18:1478-1489. [PMID: 34595731 PMCID: PMC8608971 DOI: 10.1007/s13311-021-01115-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/01/2021] [Indexed: 02/04/2023] Open
Abstract
Recent advances in molecular and cellular engineering, such as human cell reprogramming, genome editing, and patient-specific organoids, have provided unprecedented opportunities for investigating human disorders in both animals and human-based models at an improved pace and precision. This progress will inevitably lead to the development of innovative drug-screening platforms and new patient-specific therapeutics. In this review, we discuss recent advances that have been made using zebrafish and human-induced pluripotent stem cell (iPSC)-derived neurons and organoids for modeling genetic epilepsies. We also provide our prospective on how these models can potentially be combined to build new screening platforms for antiseizure and antiepileptogenic drug discovery that harness the robustness and tractability of zebrafish models as well as the patient-specific genetics and biology of iPSC-derived neurons and organoids.
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141
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Boscia F, Elkjaer ML, Illes Z, Kukley M. Altered Expression of Ion Channels in White Matter Lesions of Progressive Multiple Sclerosis: What Do We Know About Their Function? Front Cell Neurosci 2021; 15:685703. [PMID: 34276310 PMCID: PMC8282214 DOI: 10.3389/fncel.2021.685703] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Accepted: 05/23/2021] [Indexed: 12/19/2022] Open
Abstract
Despite significant advances in our understanding of the pathophysiology of multiple sclerosis (MS), knowledge about contribution of individual ion channels to axonal impairment and remyelination failure in progressive MS remains incomplete. Ion channel families play a fundamental role in maintaining white matter (WM) integrity and in regulating WM activities in axons, interstitial neurons, glia, and vascular cells. Recently, transcriptomic studies have considerably increased insight into the gene expression changes that occur in diverse WM lesions and the gene expression fingerprint of specific WM cells associated with secondary progressive MS. Here, we review the ion channel genes encoding K+, Ca2+, Na+, and Cl- channels; ryanodine receptors; TRP channels; and others that are significantly and uniquely dysregulated in active, chronic active, inactive, remyelinating WM lesions, and normal-appearing WM of secondary progressive MS brain, based on recently published bulk and single-nuclei RNA-sequencing datasets. We discuss the current state of knowledge about the corresponding ion channels and their implication in the MS brain or in experimental models of MS. This comprehensive review suggests that the intense upregulation of voltage-gated Na+ channel genes in WM lesions with ongoing tissue damage may reflect the imbalance of Na+ homeostasis that is observed in progressive MS brain, while the upregulation of a large number of voltage-gated K+ channel genes may be linked to a protective response to limit neuronal excitability. In addition, the altered chloride homeostasis, revealed by the significant downregulation of voltage-gated Cl- channels in MS lesions, may contribute to an altered inhibitory neurotransmission and increased excitability.
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Affiliation(s)
- Francesca Boscia
- Division of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine, University of Naples "Federico II", Naples, Italy
| | - Maria Louise Elkjaer
- Neurology Research Unit, Department of Clinical Research, University of Southern Denmark, Odense, Denmark.,Department of Neurobiology Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Zsolt Illes
- Neurology Research Unit, Department of Clinical Research, University of Southern Denmark, Odense, Denmark.,Department of Neurobiology Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark.,Department of Neurology, Odense University Hospital, Odense, Denmark
| | - Maria Kukley
- Achucarro Basque Center for Neuroscience, Leioa, Spain.,Ikerbasque Basque Foundation for Science, Bilbao, Spain
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142
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Vuralli D, Karatas H, Yemisci M, Bolay H. Updated review on the link between cortical spreading depression and headache disorders. Expert Rev Neurother 2021; 21:1069-1084. [PMID: 34162288 DOI: 10.1080/14737175.2021.1947797] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
INTRODUCTION Experimental animal studies have revealed mechanisms that link cortical spreading depression (CSD) to the trigeminal activation mediating lateralized headache. However, conventional CSD as seen in lissencephalic brain is insufficient to explain some clinical features of aura and migraine headache. AREAS COVERED The importance of CSD in headache development including dysfunction of the thalamocortical network, neuroinflammation, calcitonin gene-related peptide, transgenic models, and the role of CSD in migraine triggers, treatment options, neuromodulation and future directions are reviewed. EXPERT OPINION The conventional understanding of CSD marching across the hemisphere is invalid in gyrencephalic brains. Thalamocortical dysfunction and interruption of functional cortical network systems by CSD, may provide alternative explanations for clinical manifestations of migraine phases including aura. Not all drugs showing CSD blocking properties in lissencephalic brains, have efficacy in migraine headache and monoclonal antibodies against CGRP ligand/receptors which are effective in migraine treatment, have no impact on aura in humans or CSD properties in rodents. Functional networks and molecular mechanisms mediating and amplifying the effects of limited CSD in migraine brain remain to be investigated to define new targets.
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Affiliation(s)
- Doga Vuralli
- Department of Neurology and Algology, Gazi University Faculty of Medicine, Besevler, Ankara, Turkey.,Neuropsychiatry Center, Gazi University, Besevler, Ankara, Turkey.,Neuroscience and Neurotechnology Center of Excellence (NÖROM), Ankara, Turkey
| | - Hulya Karatas
- Neuroscience and Neurotechnology Center of Excellence (NÖROM), Ankara, Turkey.,Institute of Neurological Sciences and Psychiatry, Hacettepe University, Ankara, Turkey
| | - Muge Yemisci
- Neuroscience and Neurotechnology Center of Excellence (NÖROM), Ankara, Turkey.,Institute of Neurological Sciences and Psychiatry, Hacettepe University, Ankara, Turkey.,Department of Neurology, Faculty of Medicine, Hacettepe University, Ankara, Turkey
| | - Hayrunnisa Bolay
- Department of Neurology and Algology, Gazi University Faculty of Medicine, Besevler, Ankara, Turkey.,Neuropsychiatry Center, Gazi University, Besevler, Ankara, Turkey.,Neuroscience and Neurotechnology Center of Excellence (NÖROM), Ankara, Turkey
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143
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Miljanovic N, Hauck SM, van Dijk RM, Di Liberto V, Rezaei A, Potschka H. Proteomic signature of the Dravet syndrome in the genetic Scn1a-A1783V mouse model. Neurobiol Dis 2021; 157:105423. [PMID: 34144125 DOI: 10.1016/j.nbd.2021.105423] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2021] [Revised: 05/14/2021] [Accepted: 06/08/2021] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Dravet syndrome is a rare, severe pediatric epileptic encephalopathy associated with intellectual and motor disabilities. Proteomic profiling in a mouse model of Dravet syndrome can provide information about the molecular consequences of the genetic deficiency and about pathophysiological mechanisms developing during the disease course. METHODS A knock-in mouse model of Dravet syndrome with Scn1a haploinsufficiency was used for whole proteome, seizure, and behavioral analysis. Hippocampal tissue was dissected from two- (prior to epilepsy manifestation) and four- (following epilepsy manifestation) week-old male mice and analyzed using LC-MS/MS with label-free quantification. Proteomic data sets were subjected to bioinformatic analysis including pathway enrichment analysis. The differential expression of selected proteins was confirmed by immunohistochemical staining. RESULTS The findings confirmed an increased susceptibility to hyperthermia-associated seizures, the development of spontaneous seizures, and behavioral alterations in the novel Scn1a-A1873V mouse model of Dravet syndrome. As expected, proteomic analysis demonstrated more pronounced alterations following epilepsy manifestation. In particular, proteins involved in neurotransmitter dynamics, receptor and ion channel function, synaptic plasticity, astrogliosis, neoangiogenesis, and nitric oxide signaling showed a pronounced regulation in Dravet mice. Pathway enrichment analysis identified several significantly regulated pathways at the later time point, with pathways linked to synaptic transmission and glutamatergic signaling dominating the list. CONCLUSION In conclusion, the whole proteome analysis in a mouse model of Dravet syndrome demonstrated complex molecular alterations in the hippocampus. Some of these alterations may have an impact on excitability or may serve a compensatory function, which, however, needs to be further confirmed by future investigations. The proteomic data indicate that, due to the molecular consequences of the genetic deficiency, the pathophysiological mechanisms may become more complex during the course of the disease. As a result, the management of Dravet syndrome may need to consider further molecular and cellular alterations. Ensuing functional follow-up studies, this data set may provide valuable guidance for the future development of novel therapeutic approaches.
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Affiliation(s)
- Nina Miljanovic
- Institute of Pharmacology, Toxicology & Pharmacy, Ludwig-Maximilians-University (LMU), Munich, Germany; Graduate School of Systemic Neurosciences (GSN), Ludwig-Maximilians-University (LMU), Munich, Germany
| | - Stefanie M Hauck
- Research Unit Protein Science, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Germany
| | - R Maarten van Dijk
- Institute of Pharmacology, Toxicology & Pharmacy, Ludwig-Maximilians-University (LMU), Munich, Germany
| | - Valentina Di Liberto
- Institute of Pharmacology, Toxicology & Pharmacy, Ludwig-Maximilians-University (LMU), Munich, Germany
| | - Ali Rezaei
- Institute of Pharmacology, Toxicology & Pharmacy, Ludwig-Maximilians-University (LMU), Munich, Germany; Graduate School of Systemic Neurosciences (GSN), Ludwig-Maximilians-University (LMU), Munich, Germany
| | - Heidrun Potschka
- Institute of Pharmacology, Toxicology & Pharmacy, Ludwig-Maximilians-University (LMU), Munich, Germany.
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144
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Thompson CH, Ben-Shalom R, Bender KJ, George AL. Alternative splicing potentiates dysfunction of early-onset epileptic encephalopathy SCN2A variants. J Gen Physiol 2021; 152:133672. [PMID: 31995133 PMCID: PMC7054859 DOI: 10.1085/jgp.201912442] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 01/07/2020] [Indexed: 01/06/2023] Open
Abstract
Epileptic encephalopathies are severe forms of infantile-onset epilepsy often complicated by severe neurodevelopmental impairments. Some forms of early-onset epileptic encephalopathy (EOEE) have been associated with variants in SCN2A, which encodes the brain voltage-gated sodium channel NaV1.2. Many voltage-gated sodium channel genes, including SCN2A, undergo developmentally regulated mRNA splicing. The early onset of these disorders suggests that developmentally regulated alternative splicing of NaV1.2 may be an important consideration when elucidating the pathophysiological consequences of epilepsy-associated variants. We hypothesized that EOEE-associated NaV1.2 variants would exhibit greater dysfunction in a splice isoform that is prominently expressed during early development. We engineered five EOEE-associated NaV1.2 variants (T236S, E999K, S1336Y, T1623N, and R1882Q) into the adult and neonatal splice isoforms of NaV1.2 and performed whole-cell voltage clamp to elucidate their functional properties. All variants exhibited functional defects that could enhance neuronal excitability. Three of the five variants (T236S, E999K, and S1336Y) exhibited greater dysfunction in the neonatal isoform compared with those observed in the adult isoform. Computational modeling of a developing cortical pyramidal neuron indicated that T236S, E999K, S1336Y, and R1882Q showed hyperexcitability preferentially in immature neurons. These results suggest that both splice isoform and neuronal developmental stage influence how EOEE-associated NaV1.2 variants affect neuronal excitability.
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Affiliation(s)
- Christopher H Thompson
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL
| | - Roy Ben-Shalom
- Center for Integrative Neuroscience, Kavli Institute for Fundamental Neuroscience, Department of Neurology, University of California, San Francisco, San Francisco, CA
| | - Kevin J Bender
- Center for Integrative Neuroscience, Kavli Institute for Fundamental Neuroscience, Department of Neurology, University of California, San Francisco, San Francisco, CA
| | - Alfred L George
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL
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145
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Abstract
Pathogenic variants in epilepsy genes result in a spectrum of clinical severity. One source of phenotypic heterogeneity is modifier genes that affect expressivity of a primary pathogenic variant. Mouse epilepsy models also display varying degrees of clinical severity on different genetic backgrounds. Mice with heterozygous deletion of Scn1a (Scn1a+/−) model Dravet syndrome, a severe epilepsy most often caused by SCN1A haploinsufficiency. Scn1a+/− mice recapitulate features of Dravet syndrome, including spontaneous seizures, sudden death, and cognitive/behavioral deficits. Scn1a+/− mice maintained on the 129S6/SvEvTac (129) strain have normal lifespan and no spontaneous seizures. In contrast, admixture with C57BL/6J (B6) results in epilepsy and premature lethality. We previously mapped Dravet Survival Modifier loci (Dsm1-Dsm5) responsible for strain-dependent differences in survival. Gabra2, encoding the GABAA α2 subunit, was nominated as a candidate modifier at Dsm1. Direct measurement of GABAA receptors found lower abundance of α2-containing receptors in hippocampal synapses of B6 mice relative to 129. We also identified a B6-specific single nucleotide deletion within Gabra2 that lowers mRNA and protein by nearly 50%. Repair of this deletion reestablished normal levels of Gabra2 expression. In this study, we used B6 mice with a repaired Gabra2 allele to evaluate Gabra2 as a genetic modifier of severity in Scn1a+/− mice. Gabra2 repair restored transcript and protein expression, increased abundance of α2-containing GABAA receptors in hippocampal synapses, and rescued epilepsy phenotypes of Scn1a+/− mice. These findings validate Gabra2 as a genetic modifier of Dravet syndrome, and support enhancing function of α2-containing GABAA receptors as treatment strategy for Dravet syndrome.
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146
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Decoding the Transcriptional Response to Ischemic Stroke in Young and Aged Mouse Brain. Cell Rep 2021; 31:107777. [PMID: 32553170 DOI: 10.1016/j.celrep.2020.107777] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 03/25/2020] [Accepted: 05/26/2020] [Indexed: 12/17/2022] Open
Abstract
Ischemic stroke is a well-recognized disease of aging, yet it is unclear how the age-dependent vulnerability occurs and what are the underlying mechanisms. To address these issues, we perform a comprehensive RNA-seq analysis of aging, ischemic stroke, and their interaction in 3- and 18-month-old mice. We assess differential gene expression across injury status and age, estimate cell type proportion changes, assay the results against a range of transcriptional signatures from the literature, and perform unsupervised co-expression analysis, identifying modules of genes with varying response to injury. We uncover downregulation of axonal and synaptic maintenance genetic program, and increased activation of type I interferon (IFN-I) signaling following stroke in aged mice. Together, these results paint a picture of ischemic stroke as a complex age-related disease and provide insights into interaction of aging and stroke on cellular and molecular level.
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147
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Suleimanova A, Talanov M, van den Maagdenberg AMJM, Giniatullin R. Deciphering in silico the Role of Mutated Na V 1.1 Sodium Channels in Enhancing Trigeminal Nociception in Familial Hemiplegic Migraine Type 3. Front Cell Neurosci 2021; 15:644047. [PMID: 34135733 PMCID: PMC8200561 DOI: 10.3389/fncel.2021.644047] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 05/06/2021] [Indexed: 12/24/2022] Open
Abstract
Familial hemiplegic migraine type 3 (FHM3) is caused by gain-of-function mutations in the SCN1A gene that encodes the α1 subunit of voltage-gated NaV1.1 sodium channels. The high level of expression of NaV1.1 channels in peripheral trigeminal neurons may lead to abnormal nociceptive signaling thus contributing to migraine pain. NaV1.1 dysfunction is relevant also for other neurological disorders, foremost epilepsy and stroke that are comorbid with migraine. Here we used computer modeling to test the functional role of FHM3-mutated NaV1.1 channels in mechanisms of trigeminal pain. The activation of Aδ-fibers was studied for two algogens, ATP and 5-HT, operating through P2X3 and 5-HT3 receptors, respectively, at trigeminal nerve terminals. In WT Aδ-fibers of meningeal afferents, NaV1.1 channels efficiently participate in spike generation induced by ATP and 5-HT supported by NaV1.6 channels. Of the various FHM3 mutations tested, the L263V missense mutation, with a longer activation state and lower activation voltage, resulted in the most pronounced spiking activity. In contrast, mutations that result in a loss of NaV1.1 function largely reduced firing of trigeminal nerve fibers. The combined activation of P2X3 and 5-HT3 receptors and branching of nerve fibers resulted in very prolonged and high-frequency spiking activity in the mutants compared to WT. We identified, in silico, key determinants of long-lasting nociceptive activity in FHM3-mutated Aδ-fibers that naturally express P2X3 and 5-HT3 receptors and suggest mutant-specific correction options. Modeled trigeminal nerve firing was significantly higher for FHM3 mutations, compared to WT, suggesting that pronounced nociceptive signaling may contribute to migraine pain.
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Affiliation(s)
- Alina Suleimanova
- Institute of Information Technology and Intelligent Systems, Kazan Federal University, Kazan, Russia
| | - Max Talanov
- Institute of Information Technology and Intelligent Systems, Kazan Federal University, Kazan, Russia
| | - Arn M J M van den Maagdenberg
- Department of Neurology, Leiden University Medical Center, Leiden, Netherlands.,Department of Human Genetics, Leiden University Medical Center, Leiden, Netherlands
| | - Rashid Giniatullin
- Laboratory of Neurobiology, Kazan Federal University, Kazan, Russia.,A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
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148
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Abstract
dCas9-Based Scn1a Gene Activation Restores Inhibitory Interneuron Excitability and Attenuates Seizures in Dravet Syndrome Mice Colasante G, Lignani G, Brusco S, et al. Mol Ther. 2020;28(1):235-253. doi:10.1016/j.ymthe.2019.08.018 Dravet syndrome (DS) is a severe epileptic encephalopathy caused mainly by heterozygous loss-of-function mutations of the SCN1A gene, indicating haploinsufficiency as the pathogenic mechanism. Here, we tested whether catalytically dead Cas9 (dCas9)-mediated Scn1a gene activation can rescue Scn1a haploinsufficiency in a mouse DS model and restore physiological levels of its gene product, the Nav1.1 voltage-gated sodium channel. We screened single guide RNAs (sgRNAs) for their ability to stimulate Scn1a transcription in association with the dCas9 activation system. We identified a specific sgRNA that increases Scn1a gene expression levels in cell lines and primary neurons with high specificity. Nav1.1 protein levels were augmented, as was the ability of wild-type immature GABAergic interneurons to fire action potentials. A similar enhancement of Scn1a transcription was achieved in mature DS interneurons, rescuing their ability to fire. To test the therapeutic potential of this approach, we delivered the Scn1a-dCas9 activation system to DS pups using adeno-associated viruses. Parvalbumin interneurons recovered their firing ability, and febrile seizures were significantly attenuated. Our results pave the way for exploiting dCas9-based gene activation as an effective and targeted approach to DS and other disorders resulting from altered gene dosage. Scn8a Antisense Oligonucleotide Is Protective in Mouse Models of SCN8A Encephalopathy and Dravet syndrome Lenk GM, Jafar Nejad P, Hill SF, et al. Ann Neurol. 2020;87(3):339-346. doi:10.1002/ana.25676 SCN8A encephalopathy is a developmental and epileptic encephalopathy caused by de novo gain-of-function mutations of sodium channel Nav 1.6 that result in neuronal hyperactivity. Affected individuals exhibit early-onset drug-resistant seizures, developmental delay, and cognitive impairment. This study was carried out to determine whether reducing the abundance of the Scn8a transcript with an antisense oligonucleotide (ASO) would delay seizure onset and prolong survival in a mouse model of SCN8A encephalopathy. Antisense oligonucleotide treatment was tested in a conditional mouse model with Cre-dependent expression of the pathogenic patient SCN8A mutation p.Arg1872Trp (R1872 W). This model exhibits early onset of seizures, rapid progression, and 100% penetrance. An Scn1a+/− haploinsufficient mouse model of Dravet syndrome was also treated. Antisense oligonucleotide was administered by intracerebroventricular injection at postnatal day 2, followed in some cases by stereotactic injection at postnatal day 30. We observed a dose-dependent increase in length of survival from 15 to 65 days in the Scn8a-R1872W/+ mice treated with ASO. Electroencephalographic recordings were normal prior to seizure onset. Weight gain and activity in an open field were unaffected, but treated mice were less active in a wheel running assay. A single treatment with Scn8a ASO extended survival of Dravet syndrome mice from 3 weeks to >5 months. Reduction of Scn8a transcript by 25% to 50% delayed seizure onset and lethality in mouse models of SCN8A encephalopathy and Dravet syndrome. Reduction of SCN8A transcript is a promising approach to treatment of intractable childhood epilepsies.
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149
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Ahmed OJ. Slower, Fewer Hippocampal Ripples in Loss-of-Function Model of Dravet Syndrome. Epilepsy Curr 2021; 20:387-389. [PMID: 34029363 PMCID: PMC7818209 DOI: 10.1177/1535759720960470] [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] [Indexed: 11/24/2022] Open
Abstract
Impairment of Sharp-Wave Ripples in a Murine Model of Dravet Syndrome Cheah CS, Lundstrom BN, Catterall WA, Oakley JC. J Neurosci.
2019;39(46):9251-9260. doi:10.1523/JNEUROSCI.0890-19 Dravet syndrome (DS) is a severe early-onset epilepsy associated with heterozygous
loss-of-function mutations in SCN1A. Animal models of DS with global Scn1a
haploinsufficiency recapitulate the DS phenotype, including seizures, premature death,
and impaired spatial memory performance. Spatial memory requires hippocampal
sharp-wave ripples (SPW-Rs), which consist of high-frequency field potential
oscillations (ripples, 100-260 Hz) superimposed on a slower SPW. Published in vitro
electrophysiologic recordings in DS mice demonstrate reduced firing of GABAergic
inhibitory neurons, which are essential for the formation of SPW-R complexes. Here, in
vivo electrophysiologic recordings of hippocampal local field potential in both male
and female mice demonstrate that Scn1a haploinsufficiency slows intrinsic ripple
frequency and reduces the rate of SPW-R occurrence. In DS mice, peak ripple-band power
is shifted to lower frequencies, average intertrough intervals of individually
detected ripples are slower, and the rate of SPW-R generation is reduced, while SPW
amplitude remains unaffected. These alterations in SPW-R properties, in combination
with published reductions in interneuron function in DS, suggest a direct link between
reduced inhibitory neuron excitability and impaired SPW-R function. A simple
interconnected, conductance-based in silico interneuron network model was used to
determine whether reduced sodium conductance is sufficient to slow ripple frequency,
and stimulation with a modeled SPW demonstrates that reduced sodium conductance alone
is sufficient to slow oscillatory frequencies. These findings forge a potential
mechanistic link between impaired SPW-R generation and Scn1a mutation in DS mice,
expanding the set of disorders in which SPW-R dysfunction contributes to impaired
memory.
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150
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Uchino K, Kawano H, Tanaka Y, Adaniya Y, Asahara A, Deshimaru M, Kubota K, Watanabe T, Katsurabayashi S, Iwasaki K, Hirose S. Inhibitory synaptic transmission is impaired at higher extracellular Ca 2+ concentrations in Scn1a +/- mouse model of Dravet syndrome. Sci Rep 2021; 11:10634. [PMID: 34017040 PMCID: PMC8137694 DOI: 10.1038/s41598-021-90224-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 05/07/2021] [Indexed: 12/17/2022] Open
Abstract
Dravet syndrome (DS) is an intractable form of childhood epilepsy that occurs in infancy. More than 80% of all patients have a heterozygous abnormality in the SCN1A gene, which encodes a subunit of Na+ channels in the brain. However, the detailed pathogenesis of DS remains unclear. This study investigated the synaptic pathogenesis of this disease in terms of excitatory/inhibitory balance using a mouse model of DS. We show that excitatory postsynaptic currents were similar between Scn1a knock-in neurons (Scn1a+/- neurons) and wild-type neurons, but inhibitory postsynaptic currents were significantly lower in Scn1a+/- neurons. Moreover, both the vesicular release probability and the number of inhibitory synapses were significantly lower in Scn1a+/- neurons compared with wild-type neurons. There was no proportional increase in inhibitory postsynaptic current amplitude in response to increased extracellular Ca2+ concentrations. Our study revealed that the number of inhibitory synapses is significantly reduced in Scn1a+/- neurons, while the sensitivity of inhibitory synapses to extracellular Ca2+ concentrations is markedly increased. These data suggest that Ca2+ tethering in inhibitory nerve terminals may be disturbed following the synaptic burst, likely leading to epileptic symptoms.
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Affiliation(s)
- Kouya Uchino
- Department of Neuropharmacology, Faculty of Pharmaceutical Sciences, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka, 814-0180, Japan
| | - Hiroyuki Kawano
- Research Institute for the Molecular Pathogeneses of Epilepsy, Fukuoka University, Fukuoka, Japan
| | - Yasuyoshi Tanaka
- Research Institute for the Molecular Pathogeneses of Epilepsy, Fukuoka University, Fukuoka, Japan
| | - Yuna Adaniya
- Department of Neuropharmacology, Faculty of Pharmaceutical Sciences, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka, 814-0180, Japan
| | - Ai Asahara
- Department of Neuropharmacology, Faculty of Pharmaceutical Sciences, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka, 814-0180, Japan
| | - Masanobu Deshimaru
- Research Institute for the Molecular Pathogeneses of Epilepsy, Fukuoka University, Fukuoka, Japan
| | - Kaori Kubota
- Department of Neuropharmacology, Faculty of Pharmaceutical Sciences, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka, 814-0180, Japan
| | - Takuya Watanabe
- Department of Neuropharmacology, Faculty of Pharmaceutical Sciences, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka, 814-0180, Japan
| | - Shutaro Katsurabayashi
- Department of Neuropharmacology, Faculty of Pharmaceutical Sciences, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka, 814-0180, Japan.
- Research Institute for the Molecular Pathogeneses of Epilepsy, Fukuoka University, Fukuoka, Japan.
| | - Katsunori Iwasaki
- Department of Neuropharmacology, Faculty of Pharmaceutical Sciences, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka, 814-0180, Japan
| | - Shinichi Hirose
- Research Institute for the Molecular Pathogeneses of Epilepsy, Fukuoka University, Fukuoka, Japan
- Department of Pediatrics, School of Medicine, Fukuoka University, Fukuoka, Japan
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