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1.
Zhejiang Da Xue Xue Bao Yi Xue Ban ; 49(1): 71-75, 2020 May 25.
Artigo em Chinês | MEDLINE | ID: mdl-32621420

RESUMO

OBJECTIVE: To investigate the effect of calmodulin (CaM) and its mutants on binding to voltage-gated Na channel isoleucine-glutamine domain (NaV1.2 IQ). METHODS: The cDNA of NaV1.2 IQ was constructed by PCR technique, CaM mutants CaM12, CaM34 and CaM1234 were constructed with QuickchangeTM site-directed mutagenesis kit (QIAGEN). The binding of NaV1.2 IQ to CaM and CaM mutants under calcium and calcium free conditions were detected by pull-down assay. RESULTS: NaV1.2 IQ and CaM were bound to each other at different calcium concentrations, while GST alone did not bind to CaM. The binding affinity of CaM and NaV1.2 IQ at [Ca2+]-free was greater than that at 100 nmol/L [Ca2+] (P < 0.05). In the absence of calcium, the binding amount of CaM wild-type to NaV1.2 IQ was greater than that of its mutant, and the binding affinity of CaM1234 to NaV1.2 IQ was the weakest among the three mutants (P < 0.05). CONCLUSIONS: The binding ability of CaM and CaM mutants to NaV1.2 IQ is Ca2+-dependent. This study has revealed a new mechanism of NaV1.2 regulated by CaM, which would be useful for the study of ion channel related diseases.


Assuntos
Calmodulina , Canal de Sódio Disparado por Voltagem NAV1.2 , Cálcio/metabolismo , Calmodulina/genética , Calmodulina/metabolismo , Mutação , Canal de Sódio Disparado por Voltagem NAV1.2/metabolismo , Ligação Proteica/genética
3.
Eur J Paediatr Neurol ; 24: 117-122, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31924505

RESUMO

Pathogenic variants in SCN2A are reported in a spectrum of neurodevelopmental disorders including developmental and epileptic encephalopathies, benign familial neonatal-infantile seizures, episodic ataxia, and autism spectrum disorder and intellectual disability with and without seizures. To date, more than 300 patients with SCN2A variants have been published, the majority presenting with epilepsy. Large cohort studies and variant-specific electrophysiology, have enabled the delineation of different SCN2A-epilepsy phenotypes, phenotype-genotype correlations, prediction of pharmacosensitivity to sodium channel blockers and long-term prognostication for clinicians and families. Herein, we summarise the core phenotypes of SCN2A-related epilepsy, genotype-phenotype correlations, response to medication and future research.


Assuntos
Epilepsia/genética , Canal de Sódio Disparado por Voltagem NAV1.2/genética , Estudos de Coortes , Feminino , Estudos de Associação Genética , Humanos , Lactente , Masculino , Mutação , Fenótipo
4.
J Biol Chem ; 295(5): 1315-1327, 2020 01 31.
Artigo em Inglês | MEDLINE | ID: mdl-31871053

RESUMO

Pain is a significant public health burden in the United States, and current treatment approaches rely heavily on opioids, which often have limited efficacy and can lead to addiction. In humans, functional loss of the voltage-gated sodium channel Nav1.7 leads to pain insensitivity without deficits in the central nervous system. Accordingly, discovery of a selective Nav1.7 antagonist should provide an analgesic without abuse liability and an improved side-effect profile. Huwentoxin-IV, a component of tarantula venom, potently blocks sodium channels and is an attractive scaffold for engineering a Nav1.7-selective molecule. To define the functional impact of alterations in huwentoxin-IV sequence, we produced a library of 373 point mutants and tested them for Nav1.7 and Nav1.2 activity. We then combined favorable individual changes to produce combinatorial mutants that showed further improvements in Nav1.7 potency (E1N, E4D, Y33W, Q34S-Nav1.7 pIC50 = 8.1 ± 0.08) and increased selectivity over other Nav isoforms (E1N, R26K, Q34S, G36I, Nav1.7 pIC50 = 7.2 ± 0.1, Nav1.2 pIC50 = 6.1 ± 0.18, Nav1.3 pIC50 = 6.4 ± 1.0), Nav1.4 is inactive at 3 µm, and Nav1.5 is inactive at 10 µm We also substituted noncoded amino acids at select positions in huwentoxin-IV. Based on these results, we identify key determinants of huwentoxin's Nav1.7 inhibition and propose a model for huwentoxin-IV's interaction with Nav1.7. These findings uncover fundamental features of huwentoxin involved in Nav1.7 blockade, provide a foundation for additional optimization of this molecule, and offer a basis for the development of a safe and effective analgesic.


Assuntos
Analgésicos/farmacologia , Canal de Sódio Disparado por Voltagem NAV1.7/efeitos dos fármacos , Venenos de Aranha/química , Venenos de Aranha/genética , Bloqueadores do Canal de Sódio Disparado por Voltagem/farmacologia , Sequência de Aminoácidos/genética , Desenvolvimento de Medicamentos , Células HEK293 , Humanos , Simulação de Acoplamento Molecular , Mutagênese , Canal de Sódio Disparado por Voltagem NAV1.2/efeitos dos fármacos , Canal de Sódio Disparado por Voltagem NAV1.2/metabolismo , Canal de Sódio Disparado por Voltagem NAV1.7/metabolismo , Dor/tratamento farmacológico , Biblioteca de Peptídeos , Mutação Puntual , Engenharia de Proteínas , Isoformas de Proteínas , Proteínas Recombinantes , Venenos de Aranha/isolamento & purificação
5.
eNeuro ; 6(5)2019.
Artigo em Inglês | MEDLINE | ID: mdl-31558572

RESUMO

Over 150 mutations in the SCN2A gene, which encodes the neuronal Nav1.2 protein, have been implicated in human epilepsy cases. Of these, R1882Q and R853Q are two of the most commonly reported mutations. This study utilized voltage-clamp electrophysiology to characterize the biophysical effects of the R1882Q and R853Q mutations on the hNav1.2 channel, including their effects on resurgent current and gating pore current, which are not typically investigated in the study of Nav1.2 channel mutations. HEK cells transiently transfected with DNA encoding either wild-type (WT) or mutant hNav1.2 revealed that the R1882Q mutation induced a gain-of-function phenotype, including slowed fast inactivation, depolarization of the voltage dependence of inactivation, and increased persistent current. In this model system, the R853Q mutation primarily produced loss-of-function effects, including reduced transient current amplitude and density, hyperpolarization of the voltage dependence of inactivation, and decreased persistent current. The presence of a Navß4 peptide (KKLITFILKKTREK-OH) in the pipette solution induced resurgent currents, which were increased by the R1882Q mutation and decreased by the R853Q mutation. Further study of the R853Q mutation in Xenopus oocytes indicated a reduced surface expression and revealed a robust gating pore current at negative membrane potentials, a function absent in the WT channel. This not only shows that different epileptogenic point mutations in hNav1.2 have distinct biophysical effects on the channel, but also illustrates that individual mutations can have complex consequences that are difficult to identify using conventional analyses. Distinct mutations may, therefore, require tailored pharmacotherapies in order to eliminate seizures.


Assuntos
Epilepsia/genética , Ativação do Canal Iônico/genética , Canal de Sódio Disparado por Voltagem NAV1.2/genética , Potenciais de Ação/genética , Animais , Células HEK293 , Humanos , Mutação Puntual/genética , Xenopus laevis
6.
Neuron ; 103(4): 551-553, 2019 08 21.
Artigo em Inglês | MEDLINE | ID: mdl-31437449

RESUMO

Mutations in voltage-dependent sodium channels cause severe autism/intellectual disability. In this issue of Neuron, Spratt et al. (2019) show that lowering expression of Nav1.2 channels attenuates backpropagation of action potentials into dendrites of cortical neurons, preventing spike-timing-dependent synaptic plasticity.


Assuntos
Transtorno Autístico , Deficiência Intelectual , Potenciais de Ação , Dendritos , Humanos , Canal de Sódio Disparado por Voltagem NAV1.2 , Córtex Pré-Frontal
7.
J Med Case Rep ; 13(1): 266, 2019 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-31439038

RESUMO

BACKGROUND: Epilepsy is the most common neurological disorder that causes spontaneous, unprovoked, and recurrent seizures. Epilepsy is clinically and genetically heterogeneous with various modes of inheritance. The complexity of epilepsy presents a challenge and identification of the causal genetic mutation allows diagnosis, genetic counseling, predicting prognosis, and, in some cases, treatment decisions. Clinical exome sequencing is actually becoming a powerful approach for molecular diagnosis of heterogeneous neurological disorders in clinical practice. CASE PRESENTATION: We report our observations of three unrelated Moroccan patients referred to our genetics department for molecular diagnosis of epilepsy: a 4-year-old Moroccan boy, a 3-year-old Moroccan girl, and a 7-year-old Moroccan boy. Due to the heterogeneity and complexity of epilepsy, we performed clinical exome sequencing followed by targeted analysis of 936 epilepsy genes. A total of three mutations were identified in known epilepsy genes (SCN1A, SCN2A). By clinical exome sequencing, we identified two novel mutations: c.4973C>A (p.Thr1658Lys) in SCN1A gene and c.1283A>G (p.Tyr428Cys) in the SCN2A gene, whereas the third mutation c.3295G>T (p.Glu1099*) was already described in patients with Dravet syndrome. CONCLUSION: This study demonstrates that clinical exome sequencing is an effective diagnosis tool to investigate this group of diseases with huge diversity and defends its use in clinical routine.


Assuntos
Epilepsia/genética , Mutação , Canal de Sódio Disparado por Voltagem NAV1.1/genética , Canal de Sódio Disparado por Voltagem NAV1.2/genética , Criança , Pré-Escolar , Feminino , Heterozigoto , Humanos , Masculino , Marrocos , Análise de Sequência de DNA , Sequenciamento Completo do Exoma
8.
Stem Cell Res ; 39: 101488, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31272037

RESUMO

Autism spectrum disorders (ASDs) are a group of diseases that affect social interaction, communication and behavior. Molecular mechanisms involved in the pathogenesis of ASDs are complex due to genetic heterogeneity. Recently, pathogenic variants of SCN2A have been strongly associated with ASDs. Here, we generated iPSCs from a patient with ASD and a heterozygous nonsense mutation in SCN2A, by reprogramming mesenchymal stromal cells with non-integrating vectors. The generated iPSC line expresses pluripotency markers, presents a normal karyotype and is able to differentiate into the three germ layers. This iPSC line is a useful tool for modeling ASD and drug screening studies.


Assuntos
Transtorno do Espectro Autista/metabolismo , Células-Tronco Pluripotentes Induzidas/citologia , Células-Tronco Pluripotentes Induzidas/metabolismo , Canal de Sódio Disparado por Voltagem NAV1.2/genética , Transtorno do Espectro Autista/genética , Linhagem Celular , Reprogramação Celular/genética , Reprogramação Celular/fisiologia , Citometria de Fluxo , Haploinsuficiência/genética , Haploinsuficiência/fisiologia , Humanos , Cariótipo , Repetições de Microssatélites/genética , Mutação/genética , Reação em Cadeia da Polimerase em Tempo Real
9.
Stem Cell Res ; 39: 101487, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31229899

RESUMO

Activated T lymphocytes of a healthy individual were reprogrammed to induced pluripotent stem cells (iPSCs) using Sendai viral vectors. Two iPSC lines, MUSIi011-A and MUSIi011-B, were established and characterized for the expression of pluripotent markers. Both iPSC lines were able to differentiate into cells of three embryonic germ layers via embryoid body formation, exhibited normal karyotypes and were free of viral genome and transgenes at passage 15. These T lymphocyte-derived iPSCs (T-iPSCs) represent a useful starting cell source for developing next-generation immune cells such as chimeric antigen receptor (CAR)-engineered iPSC-derived T lymphocytes for the application in adoptive immunotherapy.


Assuntos
Técnicas de Cultura de Células/métodos , Células-Tronco Pluripotentes Induzidas/citologia , Linfócitos T/citologia , Transtorno do Espectro Autista , Códon sem Sentido/genética , Heterozigoto , Humanos , Células-Tronco Pluripotentes Induzidas/metabolismo , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/metabolismo , Canal de Sódio Disparado por Voltagem NAV1.2/genética
10.
Neuron ; 103(4): 673-685.e5, 2019 08 21.
Artigo em Inglês | MEDLINE | ID: mdl-31230762

RESUMO

Autism spectrum disorder (ASD) is strongly associated with de novo gene mutations. One of the most commonly affected genes is SCN2A. ASD-associated SCN2A mutations impair the encoded protein NaV1.2, a sodium channel important for action potential initiation and propagation in developing excitatory cortical neurons. The link between an axonal sodium channel and ASD, a disorder typically attributed to synaptic or transcriptional dysfunction, is unclear. Here we show that NaV1.2 is unexpectedly critical for dendritic excitability and synaptic function in mature pyramidal neurons in addition to regulating early developmental axonal excitability. NaV1.2 loss reduced action potential backpropagation into dendrites, impairing synaptic plasticity and synaptic strength, even when NaV1.2 expression was disrupted in a cell-autonomous fashion late in development. These results reveal a novel dendritic function for NaV1.2, providing insight into cellular mechanisms probably underlying circuit and behavioral dysfunction in ASD.


Assuntos
Transtorno do Espectro Autista/genética , Dendritos/fisiologia , Canal de Sódio Disparado por Voltagem NAV1.2/fisiologia , Córtex Pré-Frontal/fisiologia , Células Piramidais/fisiologia , Potenciais de Ação , Animais , Sinalização do Cálcio , Feminino , Regulação da Expressão Gênica no Desenvolvimento , Heterozigoto , Hipocampo/citologia , Hipocampo/crescimento & desenvolvimento , Hipocampo/fisiologia , Masculino , Aprendizagem em Labirinto/fisiologia , Camundongos , Potenciais Pós-Sinápticos em Miniatura/fisiologia , N-Metilaspartato/análise , Canal de Sódio Disparado por Voltagem NAV1.2/genética , Neocórtex/citologia , Neocórtex/crescimento & desenvolvimento , Neocórtex/fisiologia , Córtex Pré-Frontal/citologia , Córtex Pré-Frontal/crescimento & desenvolvimento , Engenharia de Proteínas , Comportamento Social , Ácido alfa-Amino-3-hidroxi-5-metil-4-isoxazol Propiônico/análise
11.
J Genet ; 98(2)2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31204721

RESUMO

Neuronal migration disorders (NMDs) are a heterogeneous group of conditions caused by the abnormal migration of neuroblasts in the developing brain and nervous system, resulting in severe developmental impairment, intractable epilepsy and intellectual disability (Spalice et al. 2009). To date, many genes have been identified as the leading cause of migration defects, i.e. agyria/pachygyria, polymicrogyria, heterotopias, agenesis of the corpus callosum and agenesis of the cranial nerves (Spalice et al. 2009). Here, we present a patient with early infantile epileptic encephalopathy (Ohtahara syndrome) with seizure onset on the first dayof life, severe developmental delay and an abnormal brain MRI with excessive folding of small, fused gyri and bilateral perisylvian polymicrogyria, suggestive of neuronal migration disorder. To clarify the unknown aetiology, we conducted whole-exome sequencing, which detected a de novo missense variant (c.5308A>T; p.(Met1770Leu)) in the SCN2A gene. This is a report of SCN2A gene variant identified in a patient with neuronal migration disorder which could further expand the phenotypic spectrum of these genetic disorders.


Assuntos
Mutação , Canal de Sódio Disparado por Voltagem NAV1.2/genética , Neuroimagem , Fenótipo , Espasmos Infantis/diagnóstico , Espasmos Infantis/genética , Sequência de Aminoácidos , Diagnóstico Diferencial , Humanos , Lactente , Imagem por Ressonância Magnética , Masculino , Malformações do Desenvolvimento Cortical do Grupo II/diagnóstico , Neuroimagem/métodos
13.
Eur J Paediatr Neurol ; 23(3): 438-447, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30928199

RESUMO

BACKGROUND: Pathogenic variants in SCN2A are associated with various neurological disorders including epilepsy, autism spectrum disorder and intellectual disability. Few reports have recently described SCN2A-associated episodic ataxia (EA). Our study identifies its broader clinical and genetic spectrum, and describes pharmacological approaches. RESULTS: We report 21 patients with SCN2A-associated EA, of which 9 are unpublished cases. The large majority of patients present with epileptic seizures (18/21, 86%), often starting within the first three months of life (12/18, 67%). In contrast, onset of episodic ataxia ranged from 10 months to 14 years of age. The frequency of EA episodes ranged from brief, daily events up to 1-2 episodes per year each lasting several weeks. Potential triggers include minor head traumas and sleep deprivation. Cognitive outcome is favorable in most patients with normal or mildly impaired cognitive development in 17/21 patients (81%). No clear genotype-phenotype correlations were identified in this cohort. However, two mutational hotspots were identified, i.e. 7/21 patients (33%) harbor the identical pathogenic variant p.A263V, whereas 5/21 (24%) carry pathogenic variants that affect the S4 segment and its cytoplasmic loop within the domain IV. In addition, we identified six novel pathogenic variants in SCN2A. While acetazolamide was previously reported as beneficial in SCN2A-associated EA in one case, our data show a conflicting response in 8 additional patients treated with acetazolamide: three of them profited from acetazolamide treatment, while 5/8 did not. CONCLUSIONS: Our study describes the heterogeneous clinical spectrum of SCN2A-associated EA, identifies two mutational hotspots and shows positive effects of acetazolamide in about 50%.


Assuntos
Ataxia/genética , Canal de Sódio Disparado por Voltagem NAV1.2/genética , Acetazolamida/uso terapêutico , Adulto , Anticonvulsivantes/uso terapêutico , Ataxia/tratamento farmacológico , Estudos de Coortes , Feminino , Humanos , Lactente , Masculino , Mutação
14.
Nat Commun ; 10(1): 1917, 2019 04 23.
Artigo em Inglês | MEDLINE | ID: mdl-31015467

RESUMO

STXBP1 and SCN2A gene mutations are observed in patients with epilepsies, although the circuit basis remains elusive. Here, we show that mice with haplodeficiency for these genes exhibit absence seizures with spike-and-wave discharges (SWDs) initiated by reduced cortical excitatory transmission into the striatum. Mice deficient for Stxbp1 or Scn2a in cortico-striatal but not cortico-thalamic neurons reproduce SWDs. In Stxbp1 haplodeficient mice, there is a reduction in excitatory transmission from the neocortex to striatal fast-spiking interneurons (FSIs). FSI activity transiently decreases at SWD onset, and pharmacological potentiation of AMPA receptors in the striatum but not in the thalamus suppresses SWDs. Furthermore, in wild-type mice, pharmacological inhibition of cortico-striatal FSI excitatory transmission triggers absence and convulsive seizures in a dose-dependent manner. These findings suggest that impaired cortico-striatal excitatory transmission is a plausible mechanism that triggers epilepsy in Stxbp1 and Scn2a haplodeficient mice.


Assuntos
Corpo Estriado/metabolismo , Proteínas Munc18/genética , Canal de Sódio Disparado por Voltagem NAV1.2/genética , Neocórtex/metabolismo , Convulsões/genética , Transmissão Sináptica , Potenciais de Ação/efeitos dos fármacos , Animais , Anticonvulsivantes/farmacologia , Corpo Estriado/efeitos dos fármacos , Corpo Estriado/patologia , Dioxóis/farmacologia , Eletroencefalografia , Epilepsia Tipo Ausência/tratamento farmacológico , Epilepsia Tipo Ausência/genética , Epilepsia Tipo Ausência/metabolismo , Epilepsia Tipo Ausência/fisiopatologia , Etossuximida/farmacologia , Regulação da Expressão Gênica , Haploinsuficiência , Interneurônios/efeitos dos fármacos , Interneurônios/metabolismo , Interneurônios/patologia , Camundongos , Camundongos Knockout , Proteínas Munc18/deficiência , Canal de Sódio Disparado por Voltagem NAV1.2/deficiência , Neocórtex/efeitos dos fármacos , Neocórtex/patologia , Vias Neurais/efeitos dos fármacos , Vias Neurais/metabolismo , Piperidinas/farmacologia , Receptores de AMPA/genética , Receptores de AMPA/metabolismo , Convulsões/metabolismo , Convulsões/fisiopatologia , Convulsões/prevenção & controle , Transdução de Sinais , Tálamo/efeitos dos fármacos , Tálamo/metabolismo
15.
Mol Autism ; 10: 15, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30962870

RESUMO

Background: Mutations of the SCN2A gene encoding a voltage-gated sodium channel alpha-II subunit Nav1.2 are associated with neurological disorders such as epilepsy, autism spectrum disorders, intellectual disability, and schizophrenia. However, causal relationships and pathogenic mechanisms underlying these neurological defects, especially social and psychiatric features, remain to be elucidated. Methods: We investigated the behavior of mice with a conventional or conditional deletion of Scn2a in a comprehensive test battery including open field, elevated plus maze, light-dark box, three chambers, social dominance tube, resident-intruder, ultrasonic vocalization, and fear conditioning tests. We further monitored the effects of the positive allosteric modulator of AMPA receptors CX516 on these model mice. Results: Conventional heterozygous Scn2a knockout mice (Scn2a KO/+) displayed novelty-induced exploratory hyperactivity and increased rearing. The increased vertical activity was reproduced by heterozygous inactivation of Scn2a in dorsal-telencephalic excitatory neurons but not in inhibitory neurons. Moreover, these phenotypes were rescued by treating Scn2a KO/+ mice with CX516. Additionally, Scn2a KO/+ mice displayed mild social behavior impairment, enhanced fear conditioning, and deficient fear extinction. Neuronal activity was intensified in the medial prefrontal cortex of Scn2a KO/+ mice, with an increase in the gamma band. Conclusions: Scn2a KO/+ mice exhibit a spectrum of phenotypes commonly observed in models of schizophrenia and autism spectrum disorder. Treatment with the CX516 ampakine, which ameliorates hyperactivity in these mice, could be a potential therapeutic strategy to rescue some of the disease phenotypes.


Assuntos
Ansiedade/genética , Transtorno do Espectro Autista/genética , Memória , Canal de Sódio Disparado por Voltagem NAV1.2/genética , Agitação Psicomotora/genética , Comportamento Social , Animais , Ansiedade/tratamento farmacológico , Transtorno do Espectro Autista/tratamento farmacológico , Dioxóis/uso terapêutico , Ritmo Gama , Haploinsuficiência , Masculino , Moduladores de Transporte de Membrana/uso terapêutico , Camundongos , Camundongos Endogâmicos C57BL , Fenótipo , Piperidinas/uso terapêutico , Córtex Pré-Frontal/efeitos dos fármacos , Córtex Pré-Frontal/fisiopatologia , Agitação Psicomotora/tratamento farmacológico
16.
Medicine (Baltimore) ; 98(12): e14908, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30896644

RESUMO

Genetic polymorphisms are related to the concentration and efficacy of oxcarbazepine (OXC). 10-Hydroxycarbazepine (MHD) is the major pharmacologically active metabolite of OXC, and it exerts an antiepileptic effect. This study aimed to explore the connection between the MHD concentration and genes such as ATP-binding cassette B1 (ABCB1), ATP-binding cassette C2 (ABCC2), UDP-glucuronosyltransferase-2B7 and sodium voltage-gated channel alpha subunit 2 (SCN2A), which participate in the antiepileptic function of OXC.Total 218 Chinese epileptic patients, were stratified into different groups according to their age, body mass index (BMI) and OXC efficacy. The genotypes of 7 single nucleotide polymorphisms in all subjects were determined by polymerase chain reaction-improved multiple ligase detection reaction assay. The MHD plasma concentration was detected by high-performance liquid chromatography and then standardized through dosage and body weight.In general, the ABCC2 rs2273697 mutant (P = .026) required a significantly higher standardized MHD concentration. For age groups, carriers of the ABCC2 rs2273697 mutant showed a significantly higher standardized MHD concentration than noncarriers in the juvenile group (P = .033). In terms of BMI, a significantly higher standardized MHD concentration was found in the ABCB1 rs2032582 mutant of the normal weight group (P = .026). The SCN2A rs17183814 mutant required a significantly higher OXC maintenance (P = .014) in the low-weight group, while lower OXC maintenance dose (P = .044) and higher standardized MHD concentration (P = .007) in the overweight group.The ABCC2 rs2273697 polymorphism was significantly associated with MHD plasma concentration in the whole patient cohort and in patients stratified by different ages, this finding provides potential theoretical guidance for the rational and safe clinical use of OXC.


Assuntos
Anticonvulsivantes/farmacocinética , Anticonvulsivantes/uso terapêutico , Epilepsia/tratamento farmacológico , Oxcarbazepina/farmacocinética , Oxcarbazepina/uso terapêutico , Subfamília B de Transportador de Cassetes de Ligação de ATP/genética , Adolescente , Adulto , Fatores Etários , Grupo com Ancestrais do Continente Asiático , Índice de Massa Corporal , Carbamazepina/análogos & derivados , Carbamazepina/sangue , Criança , Pré-Escolar , China , Feminino , Genótipo , Glucuronosiltransferase/genética , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Proteínas Associadas à Resistência a Múltiplos Medicamentos/genética , Canal de Sódio Disparado por Voltagem NAV1.2/genética , Polimorfismo de Nucleotídeo Único , Adulto Jovem
17.
Medicine (Baltimore) ; 98(8): e14698, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30813219

RESUMO

RATIONALE: The phenotypic spectrum caused by SCN2A mutations includes benign neonatal/infantile seizures, Ohtahara syndrome, infantile spasms, West syndrome, and other unclassified epileptic phenotypes. Mutations in SCN2A have been implicated in neonatal seizure cases. Here, we described a Chinese family with 2 members having juvenile-onset myoclonus and identified a novel SCN2A point mutation within this family. PATIENT CONCERNS: The 21-year-old male proband suffered from frequent myoclonus at 11 years old with subsequent progressive ataxia. His elder maternal half-sister also experienced myoclonus. Genomic DNA of the patients was extracted from the peripheral blood cells of the proband, elder maternal half-sister, parents, and uncle of the proband. Targeted next-generation sequencing was used to screen gene mutations in the proband. The potential functional effects of mutations within SCN2A were predicted In silico analyses. DIAGNOSES: Genetic testing revealed a novel SCN2A variant, c.T4820C, which contains a highly conserved amino acid substitution within segment S5 (p.V1607A). This mutation was predicted to produce a dysfunctional Nav1.2 protein by Mutation Taster and Protein Variation Effect Analyzer (PROVEAN). Genotype-phenotype correlation showed an incomplete penetrance of p.V1607A. INTERVENTIONS: The proband was treated by multiple antiepileptic drugs. These included carbamazepine, oxcarbazepine, valproate, and topiramate. OUTCOMES: The duration of follow up was 2 years, and the proband developed drug-resistant epilepsy. LESSONS: The case gives us the lesson that SCN2A mutation can contribute to juvenile-onset myoclonus. Our findings extend the spectrums of SCN2A mutations and the clinical features of patients with SCN2A mutations.


Assuntos
Carbamazepina , Epilepsia Mioclônica Juvenil , Canal de Sódio Disparado por Voltagem NAV1.2/genética , Adulto , Anticonvulsivantes/administração & dosagem , Anticonvulsivantes/efeitos adversos , Ataxia/diagnóstico , Ataxia/etiologia , Carbamazepina/administração & dosagem , Carbamazepina/efeitos adversos , Progressão da Doença , Epilepsia Resistente a Medicamentos/diagnóstico , Epilepsia Resistente a Medicamentos/tratamento farmacológico , Epilepsia Resistente a Medicamentos/genética , Eletroencefalografia/métodos , Feminino , Testes Genéticos/métodos , Humanos , Masculino , Anamnese , Mutação , Epilepsia Mioclônica Juvenil/diagnóstico , Epilepsia Mioclônica Juvenil/tratamento farmacológico , Epilepsia Mioclônica Juvenil/genética , Exame Neurológico/métodos , Oxcarbazepina/administração & dosagem , Oxcarbazepina/efeitos adversos , Linhagem , Ácido Valproico/administração & dosagem , Ácido Valproico/efeitos adversos
18.
Mol Med ; 25(1): 6, 2019 02 27.
Artigo em Inglês | MEDLINE | ID: mdl-30813884

RESUMO

BACKGROUND: Deleterious variants in the voltage-gated sodium channel type 2 (Nav1.2) lead to a broad spectrum of phenotypes ranging from benign familial neonatal-infantile epilepsy (BFNIE), severe developmental and epileptic encephalopathy (DEE) and intellectual disability (ID) to autism spectrum disorders (ASD). Yet, the underlying mechanisms are still incompletely understood. METHODS: To further elucidate the genotype-phenotype correlation of SCN2A variants we investigated the functional effects of six variants representing the phenotypic spectrum by whole-cell patch-clamp studies in transfected HEK293T cells and in-silico structural modeling. RESULTS: The two variants p.L1342P and p.E1803G detected in patients with early onset epileptic encephalopathy (EE) showed profound and complex changes in channel gating, whereas the BFNIE variant p.L1563V exhibited only a small gain of channel function. The three variants identified in ID patients without seizures, p.R937C, p.L611Vfs*35 and p.W1716*, did not produce measurable currents. Homology modeling of the missense variants predicted structural impairments consistent with the electrophysiological findings. CONCLUSIONS: Our findings support the hypothesis that complete loss-of-function variants lead to ID without seizures, small gain-of-function variants cause BFNIE and EE variants exhibit variable but profound Nav1.2 gating changes. Moreover, structural modeling was able to predict the severity of the variant impact, supporting a potential role of structural modeling as a prognostic tool. Our study on the functional consequences of SCN2A variants causing the distinct phenotypes of EE, BFNIE and ID contributes to the elucidation of mechanisms underlying the broad phenotypic variability reported for SCN2A variants.


Assuntos
Epilepsia Neonatal Benigna/genética , Síndromes Epilépticas/genética , Deficiência Intelectual/genética , Canal de Sódio Disparado por Voltagem NAV1.2/fisiologia , Adolescente , Criança , Epilepsia Neonatal Benigna/fisiopatologia , Síndromes Epilépticas/fisiopatologia , Estudos de Associação Genética , Células HEK293 , Humanos , Deficiência Intelectual/fisiopatologia , Fenótipo , Adulto Jovem
19.
Behav Brain Res ; 366: 118-125, 2019 07 02.
Artigo em Inglês | MEDLINE | ID: mdl-30885820

RESUMO

Nav1.1 and Nav1.2 are the voltage-gated sodium channel alpha subunit1 and 2, encoded by the genes of SCN1A and SCN2A. Previous studies have shown that chronic cerebral hypoperfusion (CCH) could induce neuropathological and cognitive impairment and increased total Nav1.1 and Nav1.2protein levels, yet the detailed mechanisms are not fully understood. MicroRNAs (miRNAs) are a class of small, non-coding RNAs that are involved in the regulation of dementia. miR-132 is known to play a key role in neurodegenerative disease. Here, we determined that miR-132 regulates Nav1.1 and Nav1.2 under CCH state. In this study, the expression of miR-132 was decreased in both the hippocampus and cortex of ratsfollowing CCH generated by bilateral common carotid artery occlusion (2VO). Lentiviral-mediated overexpression of miR-132 ameliorated dementia vulnerability induced by 2VO. At the molecular level, miR-132 repressed the increased protein expression of Nav1.1 and Nav1.2 in both the hippocampus and cortex induced by 2VO. MiR-132 suppressed, while AMO-miR-132 enhanced, the level of Nav1.1 and Nav1.2 in primary cultured neonatal rat neurons (NRNs) detected by both western blot analysis and immunofluorescence analysis. Results obtained by dual luciferase assay showed that overexpression of miR-132 inhibited the expression of Nav1.1 and Nav1.2 in human embryonic kidney 293 (HEK293T) cells. Additionally, binding-site mutation failed to influence Nav1.1 and Nav1.2, indicating that Nav1.1 and Nav1.2 are potential targets for miR-132. Taken together, our findings demonstrated that miR-132 protects against CCH-induced learning and memory impairments by down-regulating the expression of Nav1.1 and Nav1.2, and SCN1A and SCN2A are the target genes of miR-132.


Assuntos
Córtex Cerebral/metabolismo , Hipocampo/metabolismo , MicroRNAs/metabolismo , Canal de Sódio Disparado por Voltagem NAV1.1/genética , Canal de Sódio Disparado por Voltagem NAV1.1/metabolismo , Canal de Sódio Disparado por Voltagem NAV1.2/metabolismo , Animais , Isquemia Encefálica/metabolismo , Isquemia Encefálica/patologia , Córtex Cerebral/irrigação sanguínea , Córtex Cerebral/patologia , Circulação Cerebrovascular/fisiologia , Disfunção Cognitiva/metabolismo , Disfunção Cognitiva/patologia , Demência/metabolismo , Demência/patologia , Modelos Animais de Doenças , Células HEK293 , Hipocampo/irrigação sanguínea , Hipocampo/patologia , Humanos , Masculino , MicroRNAs/genética , Canal de Sódio Disparado por Voltagem NAV1.2/genética , Doenças Neurodegenerativas/metabolismo , Doenças Neurodegenerativas/patologia , Neurônios/metabolismo , Neurônios/patologia , Ratos , Ratos Sprague-Dawley , Lobo Temporal/patologia
20.
Science ; 363(6433): 1309-1313, 2019 03 22.
Artigo em Inglês | MEDLINE | ID: mdl-30765605

RESUMO

The voltage-gated sodium channel Nav1.2 is responsible for the initiation and propagation of action potentials in the central nervous system. We report the cryo-electron microscopy structure of human Nav1.2 bound to a peptidic pore blocker, the µ-conotoxin KIIIA, in the presence of an auxiliary subunit, ß2, to an overall resolution of 3.0 angstroms. The immunoglobulin domain of ß2 interacts with the shoulder of the pore domain through a disulfide bond. The 16-residue KIIIA interacts with the extracellular segments in repeats I to III, placing Lys7 at the entrance to the selectivity filter. Many interacting residues are specific to Nav1.2, revealing a molecular basis for KIIIA specificity. The structure establishes a framework for the rational design of subtype-specific blockers for Nav channels.


Assuntos
Conotoxinas/química , Canal de Sódio Disparado por Voltagem NAV1.2/química , Bloqueadores do Canal de Sódio Disparado por Voltagem/química , Sequência de Aminoácidos , Microscopia Crioeletrônica , Células HEK293 , Humanos , Conformação Proteica , Subunidade beta-2 do Canal de Sódio Disparado por Voltagem/química
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