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Fan HC, Yang MT, Lin LC, Chiang KL, Chen CM. Clinical and Genetic Features of Dravet Syndrome: A Prime Example of the Role of Precision Medicine in Genetic Epilepsy. Int J Mol Sci 2023; 25:31. [PMID: 38203200 PMCID: PMC10779156 DOI: 10.3390/ijms25010031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Revised: 12/14/2023] [Accepted: 12/17/2023] [Indexed: 01/12/2024] Open
Abstract
Dravet syndrome (DS), also known as severe myoclonic epilepsy of infancy, is a rare and drug-resistant form of developmental and epileptic encephalopathies, which is both debilitating and challenging to manage, typically arising during the first year of life, with seizures often triggered by fever, infections, or vaccinations. It is characterized by frequent and prolonged seizures, developmental delays, and various other neurological and behavioral impairments. Most cases result from pathogenic mutations in the sodium voltage-gated channel alpha subunit 1 (SCN1A) gene, which encodes a critical voltage-gated sodium channel subunit involved in neuronal excitability. Precision medicine offers significant potential for improving DS diagnosis and treatment. Early genetic testing enables timely and accurate diagnosis. Advances in our understanding of DS's underlying genetic mechanisms and neurobiology have enabled the development of targeted therapies, such as gene therapy, offering more effective and less invasive treatment options for patients with DS. Targeted and gene therapies provide hope for more effective and personalized treatments. However, research into novel approaches remains in its early stages, and their clinical application remains to be seen. This review addresses the current understanding of clinical DS features, genetic involvement in DS development, and outcomes of novel DS therapies.
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Affiliation(s)
- Hueng-Chuen Fan
- Department of Pediatrics, Tungs’ Taichung Metroharbor Hospital, Wuchi, Taichung 435, Taiwan;
- Department of Rehabilitation, Jen-Teh Junior College of Medicine, Nursing and Management, Miaoli 356, Taiwan
- Department of Life Sciences, Agricultural Biotechnology Center, National Chung Hsing University, Taichung 402, Taiwan
| | - Ming-Tao Yang
- Department of Pediatrics, Far Eastern Memorial Hospital, New Taipei City 220, Taiwan;
- Department of Chemical Engineering and Materials Science, Yuan Ze University, Taoyuan 320, Taiwan
| | - Lung-Chang Lin
- Department of Pediatrics, School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan;
- Department of Pediatrics, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung 807, Taiwan
| | - Kuo-Liang Chiang
- Department of Pediatric Neurology, Kuang-Tien General Hospital, Taichung 433, Taiwan;
- Department of Nutrition, Hungkuang University, Taichung 433, Taiwan
| | - Chuan-Mu Chen
- Department of Life Sciences, Agricultural Biotechnology Center, National Chung Hsing University, Taichung 402, Taiwan
- The iEGG and Animal Biotechnology Center, and Rong Hsing Research Center for Translational Medicine, National Chung Hsing University, Taichung 402, Taiwan
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Li L, Yuan L, Zheng W, Yang Y, Deng X, Song Z, Deng H. An SCN1A gene missense variant in a Chinese Tujia ethnic family with genetic epilepsy with febrile seizures plus. Front Neurol 2023; 14:1229569. [PMID: 37576022 PMCID: PMC10412811 DOI: 10.3389/fneur.2023.1229569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 06/30/2023] [Indexed: 08/15/2023] Open
Abstract
Genetic epilepsy with febrile seizures plus (GEFSP) is a familial epileptic syndrome that is genetically heterogeneous and inherited in an autosomal dominant form in most cases. To date, at least seven genes have been reported to associate with GEFSP. This study aimed to identify the disease-causing variant in a Chinese Tujia ethnic family with GEFSP by using whole exome sequencing, Sanger sequencing, and in silico prediction. A heterozygous missense variant c.5725A>G (p.T1909A) was identified in the sodium voltage-gated channel alpha subunit 1 gene (SCN1A) coding region. The variant co-segregated with the GEFSP phenotype in this family, and it was predicted as disease-causing by multiple in silico programs, which was proposed as the genetic cause of GEFSP, further genetically diagnosed as GEFSP2. These findings expand the genetic and phenotypic spectrum of GEFSP and should contribute to genetic diagnoses, personalized therapies, and prognoses.
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Affiliation(s)
- Ling Li
- Health Management Center, The Third Xiangya Hospital, Central South University, Changsha, China
- Center for Experimental Medicine, The Third Xiangya Hospital, Central South University, Changsha, China
| | - Lamei Yuan
- Health Management Center, The Third Xiangya Hospital, Central South University, Changsha, China
- Center for Experimental Medicine, The Third Xiangya Hospital, Central South University, Changsha, China
- Department of Neurology, The Third Xiangya Hospital, Central South University, Changsha, China
- Disease Genome Research Center, Central South University, Changsha, China
| | - Wen Zheng
- Department of Neurology, The Third Xiangya Hospital, Central South University, Changsha, China
| | - Yan Yang
- Department of Neurology, The Third Xiangya Hospital, Central South University, Changsha, China
| | - Xiong Deng
- Center for Experimental Medicine, The Third Xiangya Hospital, Central South University, Changsha, China
| | - Zhi Song
- Department of Neurology, The Third Xiangya Hospital, Central South University, Changsha, China
| | - Hao Deng
- Health Management Center, The Third Xiangya Hospital, Central South University, Changsha, China
- Center for Experimental Medicine, The Third Xiangya Hospital, Central South University, Changsha, China
- Department of Neurology, The Third Xiangya Hospital, Central South University, Changsha, China
- Disease Genome Research Center, Central South University, Changsha, China
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Dormer A, Narayanan M, Schentag J, Achinko D, Norman E, Kerrigan J, Jay G, Heydorn W. A Review of the Therapeutic Targeting of SCN9A and Nav1.7 for Pain Relief in Current Human Clinical Trials. J Pain Res 2023; 16:1487-1498. [PMID: 37168847 PMCID: PMC10166096 DOI: 10.2147/jpr.s388896] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Accepted: 03/14/2023] [Indexed: 05/13/2023] Open
Abstract
Introduction There is a great need to find alternative treatments for chronic pain which have become a healthcare problem. We discuss current therapeutic targeting Nav1.7. Areas Covered Nav1.7 is a sodium ion channel protein that is associated with several human pain genetic syndromes. It has been found that mutations associated with Nav1.7 lead to the loss of the ability to perceive pain in individuals that are otherwise normal. Several therapeutic interventions are presently undergoing preclinical and research using the methodology of damping Nav1.7 expressions as a methodology to decrease the sensation of pain leading to analgesia. Expert Opinion It is our strong belief that there is a viable future in the targeting of protein of Nav1.7 for the relief of chronic pain in humans. The review will look at the genomics associated with SCN1A and proteomic of Nav1.7 as a foundation to explain the mechanism of the therapeutic interventions targeting Nav1.7, the human disease that are associated with Nav1.7, and the current development of treatment for chronic pain whether in preclinical or clinical trials targeting Nav1.7 expressions. The development of therapeutic antagonists targeting Nav1.7 could be a viable alternative to the current treatments which have led to the opioid crisis. Therefore, Nav1.7 targeted treatment has a major clinical significance that will have positive consequences as it relates to chronic pain interventions.
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Affiliation(s)
- Anton Dormer
- Research and Development, Pepvax, Inc, Silver Spring, MD, USA
- Correspondence: Anton Dormer, Research and Development, PepVax, Inc, 8720 Georgia Ave #1000, Silver Spring, MD, 20910, USA, Email
| | | | - Jerome Schentag
- Research and Development, Pepvax, Inc, Silver Spring, MD, USA
| | - Daniel Achinko
- Research and Development, Pepvax, Inc, Silver Spring, MD, USA
| | - Elton Norman
- Research and Development, Pepvax, Inc, Silver Spring, MD, USA
| | - James Kerrigan
- Research and Development, Navintus, Inc, Princeton, NJ, USA
| | - Gary Jay
- Research and Development, Navintus, Inc, Princeton, NJ, USA
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4
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Crystal structure analysis, Hirshfeld surface analysis, spectral investigations (FT-IR, FT-R), DFT calculations, ADMET studies and molecular docking of 3H-Methyl-1H-pyrazole-1-carboxamide (3MPC). J INDIAN CHEM SOC 2022. [DOI: 10.1016/j.jics.2022.100402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Zhang Q, Si Y, Yang L, Wang L, Peng S, Chen Y, Chen M, Zhou X, Liu Z. Two Novel Peptide Toxins from the Spider Cyriopagopus longipes Inhibit Tetrodotoxin-Sensitive Sodium Channels. Toxins (Basel) 2020; 12:toxins12090529. [PMID: 32824960 PMCID: PMC7551932 DOI: 10.3390/toxins12090529] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 08/14/2020] [Accepted: 08/16/2020] [Indexed: 12/24/2022] Open
Abstract
Sodium channels play a critical role in the generation and propagation of action potentials in excitable tissues, such as nerves, cardiac muscle, and skeletal muscle, and are the primary targets of toxins found in animal venoms. Here, two novel peptide toxins (Cl6a and Cl6b) were isolated from the venom of the spider Cyriopagopus longipes and characterized. Cl6a and Cl6b were shown to be inhibitors of tetrodotoxin-sensitive (TTX-S), but not TTX-resistant, sodium channels. Among the TTX-S channels investigated, Cl6a and Cl6b showed the highest degree of inhibition against NaV1.7 (half-maximal inhibitory concentration (IC50) of 11.0 ± 2.5 nM and 18.8 ± 2.4 nM, respectively) in an irreversible manner that does not alter channel activation, inactivation, or repriming kinetics. Moreover, analysis of NaV1.7/NaV1.8 chimeric channels revealed that Cl6b is a site 4 neurotoxin. Site-directed mutagenesis analysis indicated that D816, V817, and E818 observably affected the efficacy of the Cl6b-NaV1.7 interaction, suggesting that these residues might directly affect the interaction of NaV1.7 with Cl6b. Taken together, these two novel peptide toxins act as potent and sustained NaV1.7 blockers and may have potential in the pharmacological study of sodium channels.
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Affiliation(s)
| | | | | | | | | | | | | | - Xi Zhou
- Correspondence: (X.Z); (Z.L.)
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Repurposing the Dihydropyridine Calcium Channel Inhibitor Nicardipine as a Na v1.8 Inhibitor In Vivo for Pitt Hopkins Syndrome. Pharm Res 2020; 37:127. [PMID: 32529312 DOI: 10.1007/s11095-020-02853-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2019] [Accepted: 06/05/2020] [Indexed: 12/20/2022]
Abstract
PURPOSE Individuals with the rare genetic disorder Pitt Hopkins Syndrome (PTHS) do not have sufficient expression of the transcription factor 4 (TCF4) which is located on chromosome 18. TCF4 is a basic helix-loop-helix E protein that is critical for the normal development of the nervous system and the brain in humans. PTHS patients lacking sufficient TCF4 frequently display gastrointestinal issues, intellectual disability and breathing problems. PTHS patients also commonly do not speak and display distinctive facial features and seizures. Recent research has proposed that decreased TCF4 expression can lead to the increased translation of the sodium channel Nav1.8. This in turn results in increased after-hyperpolarization as well as altered firing properties. We have recently identified through a drug repurposing screen an FDA approved dihydropyridine calcium antagonist nicardipine used to treat angina, which inhibited Nav1.8. METHODS We have now performed behavioral testing in groups of 10 male Tcf4(± ) PTHS mice dosing by oral gavage at 3 mg/kg once a day for 3 weeks using standard methods to assess sociability, nesting, fear conditioning, self-grooming, open field and test of force. RESULTS Nicardipine returned this spectrum of behavioral deficits in the Tcf4(± ) PTHS mouse model to WT levels and resulted in statistically significant results. CONCLUSIONS These in vivo results in the well characterized Tcf4(± ) PTHS mice may suggest the potential to test this already approved drug further in a clinical study with PTHS patients or suggest the potential for use off label under compassionate use with their physician.
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8
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van Groen BD, Bi C, Gaedigk R, Staggs VS, Tibboel D, de Wildt SN, Leeder JS. Alternative Splicing of the SLCO1B1 Gene: An Exploratory Analysis of Isoform Diversity in Pediatric Liver. Clin Transl Sci 2020; 13:509-519. [PMID: 31917523 PMCID: PMC7214651 DOI: 10.1111/cts.12733] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 10/26/2019] [Indexed: 11/30/2022] Open
Abstract
The hepatic influx transporter OATP1B1 (SLCO1B1) plays an important role in the disposition of endogenous substrates and drugs prescribed to children. Alternative splicing increases the diversity of protein products from > 90% of human genes and may be triggered by developmental signals. As concentrations of several endogenous OATP1B1 substrates change during growth and development, with this exploratory study we investigated age-dependent alternative splicing of SLCO1B1 mRNA in 97 postmortem livers (fetus-adolescents). Twenty-seven splice variants were detected; 10 were confirmed by additional bioinformatic analyses and verified by quantitative polymerase chain reaction, and selected for detailed analysis based on relative abundance, association with age, and overlap with an adjacent gene. Two splice variants code for reference OATP1B1 protein, and eight code for truncated proteins. The expression of eight isoforms was associated with age. We conclude that alternative splicing of SLCO1B1 occurs frequently in children; although the functional consequences remain unknown, the data raise the possibility of a regulatory role for alternative splicing in mediating developmental changes in drug disposition.
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Affiliation(s)
- Bianca D. van Groen
- Intensive Care and Department of Pediatric SurgeryErasmus MC‐Sophia Children’s HospitalRotterdamThe Netherlands
| | - Chengpeng Bi
- Division of Clinical Pharmacology, Toxicology, & Therapeutic InnovationDepartment of PediatricsChildren's Mercy Kansas CityKansas CityMissouriUSA
| | - Roger Gaedigk
- Division of Clinical Pharmacology, Toxicology, & Therapeutic InnovationDepartment of PediatricsChildren's Mercy Kansas CityKansas CityMissouriUSA
| | - Vincent S. Staggs
- Health Services and Outcomes ResearchChildren's Mercy Kansas CitySchool of MedicineUniversity of Missouri‐KansasKansas CityMissouriUSA
| | - Dick Tibboel
- Intensive Care and Department of Pediatric SurgeryErasmus MC‐Sophia Children’s HospitalRotterdamThe Netherlands
| | - Saskia N. de Wildt
- Intensive Care and Department of Pediatric SurgeryErasmus MC‐Sophia Children’s HospitalRotterdamThe Netherlands
- Department of Pharmacology and ToxicologyRadboud Institute for Health SciencesRadboud University Medical CenterNijmegenThe Netherlands
| | - J. Steven Leeder
- Division of Clinical Pharmacology, Toxicology, & Therapeutic InnovationDepartment of PediatricsChildren's Mercy Kansas CityKansas CityMissouriUSA
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9
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Pejanovic-Skobic N, Markovic I, Bozina N, Basic S. Lack of association of SCN2A rs17183814 polymorphism with the efficacy of lamotrigine monotherapy in patients with focal epilepsy from Herzegovina area, Bosnia and Herzegovina. Epilepsy Res 2019; 158:106221. [PMID: 31707316 DOI: 10.1016/j.eplepsyres.2019.106221] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 10/12/2019] [Accepted: 10/17/2019] [Indexed: 10/25/2022]
Abstract
OBJECTIVE We assessed the influence of the SCN2A gene polymorphism c.56 G > A rs17183814 on the response to lamotrigine monotherapy in patients with focal epilepsy in Herzegovina area, Bosnia and Herzegovina. MATERIAL AND METHODS For SCN2A polymorphism c.56 G > A rs17183814, one hundred patients with epilepsy who were receiving lamotrigine in monotherapy and seventy-one age and sex matched healthy controls were genotyped using TaqMan assay. All patients were Caucasians from the region of Herzegovina, Bosnia and Herzegovina. Genotyping was conducted using a polymerase chain reaction in real time. Patients were divided into two groups: responders and non-responders. RESULTS Of all patients with epilepsy, 33% were non-responders, and 67% were responders. The mean age of non-responders was 38.8 vs. group of responders in which it was 35.2. Mean age of onset of seizures in epilepsy patients was 26.7 for non-responders and 25.4 for responders. In patients with epilepsy, the mean age of seizure onset was 26.7 for non-responders and 25.4 for responders. For SCN2A c.56 G > A gene polymorphism, we did not observe any significant differences in genotypic or allelic frequency between patients with epilepsy and healthy controls. Genotype or allelic frequencies of SCN2A c.56 G > A gene polymorphism did not significantly differ for AG or GG genotypes in the non-responders vs. responders. CONCLUSION There was no significant association in patients with focal epilepsy between studied genotypes and response to lamotrigine monotherapy in Herzegovina patients with focal epilepsy. However, we need studies in a bigger cohort of patients with epilepsy to be assessed in the future.
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Affiliation(s)
- Natasa Pejanovic-Skobic
- Clinic of Neurology, University Clinical Hospital Mostar, 88000 Mostar, Bosnia and Herzegovina.
| | - Ivana Markovic
- Clinic of Neurology, Clinical Hospital Dubrava, 10000 Zagreb, Croatia
| | - Nada Bozina
- Department of Laboratory Diagnostics, University Hospital Centre Zagreb, 10000 Zagreb, Croatia
| | - Silvio Basic
- Clinic of Neurology, Clinical Hospital Dubrava, 10000 Zagreb, Croatia
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10
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Ekins S, Gerlach J, Zorn KM, Antonio BM, Lin Z, Gerlach A. Repurposing Approved Drugs as Inhibitors of K v7.1 and Na v1.8 to Treat Pitt Hopkins Syndrome. Pharm Res 2019; 36:137. [PMID: 31332533 DOI: 10.1007/s11095-019-2671-y] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 07/10/2019] [Indexed: 12/18/2022]
Abstract
PURPOSE Pitt Hopkins Syndrome (PTHS) is a rare genetic disorder caused by mutations of a specific gene, transcription factor 4 (TCF4), located on chromosome 18. PTHS results in individuals that have moderate to severe intellectual disability, with most exhibiting psychomotor delay. PTHS also exhibits features of autistic spectrum disorders, which are characterized by the impaired ability to communicate and socialize. PTHS is comorbid with a higher prevalence of epileptic seizures which can be present from birth or which commonly develop in childhood. Attenuated or absent TCF4 expression results in increased translation of peripheral ion channels Kv7.1 and Nav1.8 which triggers an increase in after-hyperpolarization and altered firing properties. METHODS We now describe a high throughput screen (HTS) of 1280 approved drugs and machine learning models developed from this data. The ion channels were expressed in either CHO (KV7.1) or HEK293 (Nav1.8) cells and the HTS used either 86Rb+ efflux (KV7.1) or a FLIPR assay (Nav1.8). RESULTS The HTS delivered 55 inhibitors of Kv7.1 (4.2% hit rate) and 93 inhibitors of Nav1.8 (7.2% hit rate) at a screening concentration of 10 μM. These datasets also enabled us to generate and validate Bayesian machine learning models for these ion channels. We also describe a structure activity relationship for several dihydropyridine compounds as inhibitors of Nav1.8. CONCLUSIONS This work could lead to the potential repurposing of nicardipine or other dihydropyridine calcium channel antagonists as potential treatments for PTHS acting via Nav1.8, as there are currently no approved treatments for this rare disorder.
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Affiliation(s)
- Sean Ekins
- Collaborations Pharmaceuticals, Inc., 840 Main Campus Drive, Lab 3510, Raleigh, North Carolina, 27606, USA.
| | - Jacob Gerlach
- Collaborations Pharmaceuticals, Inc., 840 Main Campus Drive, Lab 3510, Raleigh, North Carolina, 27606, USA
| | - Kimberley M Zorn
- Collaborations Pharmaceuticals, Inc., 840 Main Campus Drive, Lab 3510, Raleigh, North Carolina, 27606, USA
| | - Brett M Antonio
- Icagen, Inc., 4222 Emperor Blvd, Durham, North Carolina, 27703, USA
| | - Zhixin Lin
- Icagen, Inc., 4222 Emperor Blvd, Durham, North Carolina, 27703, USA
| | - Aaron Gerlach
- Icagen, Inc., 4222 Emperor Blvd, Durham, North Carolina, 27703, USA
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Belinskaia DA, Belinskaia MA, Barygin OI, Vanchakova NP, Shestakova NN. Psychotropic Drugs for the Management of Chronic Pain and Itch. Pharmaceuticals (Basel) 2019; 12:ph12020099. [PMID: 31238561 PMCID: PMC6631469 DOI: 10.3390/ph12020099] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2019] [Revised: 06/19/2019] [Accepted: 06/21/2019] [Indexed: 12/11/2022] Open
Abstract
Clinical observations have shown that patients with chronic neuropathic pain or itch exhibit symptoms of increased anxiety, depression and cognitive impairment. Such patients need corrective therapy with antidepressants, antipsychotics or anticonvulsants. It is known that some psychotropic drugs are also effective for the treatment of neuropathic pain and pruritus syndromes due to interaction with the secondary molecular targets. Our own clinical studies have identified antipruritic and/or analgesic efficacy of the following compounds: tianeptine (atypical tricyclic antidepressant), citalopram (selective serotonin reuptake inhibitor), mianserin (tetracyclic antidepressant), carbamazepine (anticonvulsant), trazodone (serotonin antagonist and reuptake inhibitor), and chlorprothixene (antipsychotic). Venlafaxine (serotonin-norepinephrine reuptake inhibitor) is known to have an analgesic effect too. The mechanism of such effect of these drugs is not fully understood. Herein we review and correlate the literature data on analgesic/antipruritic activity with pharmacological profile of these compounds.
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Affiliation(s)
- Daria A Belinskaia
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, pr. Torez 44, St. Petersburg 194223, Russia.
| | - Mariia A Belinskaia
- International Centre for Neurotherapeutics, Dublin City University, Glasnevin, Dublin 9, Ireland.
| | - Oleg I Barygin
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, pr. Torez 44, St. Petersburg 194223, Russia.
| | - Nina P Vanchakova
- Department of Pedagogy and Psychology, Faculty of Postgraduate Education, First Pavlov State Medical University, L'va Tolstogo str. 6-8, St. Petersburg 197022, Russia.
| | - Natalia N Shestakova
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, pr. Torez 44, St. Petersburg 194223, Russia.
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Heffner RS, Koay G, Heffner HE. Normal audiogram but poor sensitivity to brief sounds in mice with compromised voltage-gated sodium channels (Scn8a medJ). Hear Res 2019; 374:1-4. [PMID: 30669034 DOI: 10.1016/j.heares.2019.01.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 12/15/2018] [Accepted: 01/01/2019] [Indexed: 10/27/2022]
Abstract
The Scn8amedJ mutation of the gene for sodium channels at the nodes of Ranvier slows nerve conduction, resulting in motor abnormalities. This mutation is also associated with loss of spontaneous bursting activity in the dorsal cochlear nucleus. However initial tests of auditory sensitivity in mice homozygous for this mutation, using standard 400-ms tones, demonstrated normal hearing sensitivity. Further testing, reported here, revealed a severely compromised sensitivity to short-duration tones of 10 and 2 ms durations. Such a deficit might be expected to interfere with auditory functions that depend on rapid processing of auditory signals.
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Affiliation(s)
- Rickye S Heffner
- Department of Psychology, University of Toledo, Toledo, OH, United States.
| | - Gimseong Koay
- Department of Psychology, University of Toledo, Toledo, OH, United States.
| | - Henry E Heffner
- Department of Psychology, University of Toledo, Toledo, OH, United States.
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Zakon HH, Li W, Pillai NE, Tohari S, Shingate P, Ren J, Venkatesh B. Voltage-gated sodium channel gene repertoire of lampreys: gene duplications, tissue-specific expression and discovery of a long-lost gene. Proc Biol Sci 2017; 284:20170824. [PMID: 28931746 PMCID: PMC5627192 DOI: 10.1098/rspb.2017.0824] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Accepted: 08/17/2017] [Indexed: 12/14/2022] Open
Abstract
Studies of the voltage-gated sodium (Nav) channels of extant gnathostomes have made it possible to deduce that ancestral gnathostomes possessed four voltage-gated sodium channel genes derived from a single ancestral chordate gene following two rounds of genome duplication early in vertebrates. We investigated the Nav gene family in two species of lampreys (the Japanese lamprey Lethenteron japonicum and sea lamprey Petromyzon marinus) (jawless vertebrates-agnatha) and compared them with those of basal vertebrates to better understand the origin of Nav genes in vertebrates. We noted six Nav genes in both lamprey species, but orthology with gnathostome (jawed vertebrate) channels was inconclusive. Surprisingly, the Nav2 gene, ubiquitously found in invertebrates and believed to have been lost in vertebrates, is present in lampreys, elephant shark (Callorhinchus milii) and coelacanth (Latimeria chalumnae). Despite repeated duplication of the Nav1 family in vertebrates, Nav2 is only in single copy in those vertebrates in which it is retained, and was independently lost in ray-finned fishes and tetrapods. Of the other five Nav channel genes, most were expressed in brain, one in brain and heart, and one exclusively in skeletal muscle. Invertebrates do not express Nav channel genes in muscle. Thus, early in the vertebrate lineage Nav channels began to diversify and different genes began to express in heart and muscle.
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Affiliation(s)
- Harold H Zakon
- Department of Neuroscience, The University of Texas, Austin, TX 78712, USA
- Department of Integrative Biology, The University of Texas, Austin, TX 78712, USA
| | - Weiming Li
- Department of Fisheries and Wildlife, Michigan State University, East Lansing, MI 48824, USA
| | - Nisha E Pillai
- Comparative and Medical Genomics Lab, Institute of Molecular and Cell Biology, A*STAR, Biopolis, 138673, Singapore
| | - Sumanty Tohari
- Comparative and Medical Genomics Lab, Institute of Molecular and Cell Biology, A*STAR, Biopolis, 138673, Singapore
| | - Prashant Shingate
- Comparative and Medical Genomics Lab, Institute of Molecular and Cell Biology, A*STAR, Biopolis, 138673, Singapore
| | - Jianfeng Ren
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, College of Fisheries and Life Sciences, Shanghai Ocean University, Shanghai 201306, People's Republic of China
| | - Byrappa Venkatesh
- Comparative and Medical Genomics Lab, Institute of Molecular and Cell Biology, A*STAR, Biopolis, 138673, Singapore
- Department of Paediatrics, Yong Loo Lin School of Medicine, National University of Singapore, 119228, Singapore
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Abstract
Abstract
Painful stimuli are detected by specialized neurons, nociceptors, and are translated into action potentials, that are conducted along afferent pathways into the central nervous system, where they are conceived as pain. Voltage-gated sodium channels (NaV channels) are of paramount importance for nociceptor function, as they are responsible for the generation of action potentials and for their directed propagation. The exceptional role of sodium channel subtypes NaV1.7, NaV1.8 and NaV1.9 in the transmission of nociceptive signals has been emphasized by a variety of studies that associated genetically-induced malfunction of these channels with various pain diseases. In the following, structure and function of subtypes NaV1.7, NaV1.8 und NaV1.9 are briefly reviewed, associated pain diseases are introduced and current and future NaV-based strategies for the treatment of pain are discussed.
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Affiliation(s)
- Carla Nau
- Department of Anesthesiology and Intensive Care , University Medical Center Schleswig-Holstein, Campus Luebeck , Ratzeburger Allee 160, 23538 Luebeck , Germany , Phone: +49 451 50040701, Fax: +49 451 50040704
| | - Enrico Leipold
- Center for Molecular Biomedicine , Department of Biophysics, Friedrich Schiller University Jena , Hans-Knoell-St. 2, 07745 Jena , Germany , Phone: +49 3641 9395654, Fax: +49 3641 9395652
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Enomoto A, Seki S, Tanaka S, Ishihama K, Yamanishi T, Kogo M, Hamada S. Development of resurgent and persistent sodium currents in mesencephalic trigeminal neurons. J Neurosci Res 2017; 96:305-312. [PMID: 28752895 DOI: 10.1002/jnr.24134] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 07/11/2017] [Accepted: 07/11/2017] [Indexed: 12/18/2022]
Abstract
Sodium channels play multiple roles in the formation of neural membrane properties in mesencephalic trigeminal (Mes V) neurons and in other neural systems. Mes V neurons exhibit conditional robust high-frequency spike discharges. As previously reported, resurgent and persistent sodium currents (INaR and INaP , respectively) may carry small currents at subthreshold voltages that contribute to generation of spike firing. These currents play an important role in maintaining and allowing high-frequency spike discharge during a burst. In the present study, we investigated the developmental changes in tetrodotoxin-sensitive INaR and INaP underlying high-frequency spike discharges in Mes V neurons. Whole-cell patch-clamp recordings showed that both current densities increased one and a half times from postnatal day (P) 0-6 neurons to P7-14 neurons. Although these neurons do not exhibit subthreshold oscillations or burst discharges with high-frequency firing, INaR and INaP do exist in Mes V neurons at P0-6. When the spike frequency at rheobase was examined in firing Mes V neurons, the developmental change in firing frequency among P7-14 neurons was significant. INaR and INaP density at -40 mV also increased significantly among P7-14 neurons. The change to an increase in excitability in the P7-14 group could result from this quantitative change in INaP. In neurons older than P7 that exhibit repetitive firing, quantitative increases in INaR and INaP density may be major factors that facilitate and promote high-frequency firing as a function of age in Mes V neurons.
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Affiliation(s)
- Akifumi Enomoto
- Department of Oral and Maxillofacial Surgery, Kindai University Faculty of Medicine, Osaka-Sayama, Japan
- 1st Department of Oral Maxillofacial Surgery, Graduate School of Dentistry, Osaka University, Osaka, Japan
| | - Soju Seki
- 1st Department of Oral Maxillofacial Surgery, Graduate School of Dentistry, Osaka University, Osaka, Japan
| | - Susumu Tanaka
- 1st Department of Oral Maxillofacial Surgery, Graduate School of Dentistry, Osaka University, Osaka, Japan
| | - Kohji Ishihama
- 1st Department of Oral Maxillofacial Surgery, Graduate School of Dentistry, Osaka University, Osaka, Japan
| | - Tadashi Yamanishi
- 1st Department of Oral Maxillofacial Surgery, Graduate School of Dentistry, Osaka University, Osaka, Japan
| | - Mikihiko Kogo
- 1st Department of Oral Maxillofacial Surgery, Graduate School of Dentistry, Osaka University, Osaka, Japan
| | - Suguru Hamada
- Department of Oral and Maxillofacial Surgery, Kindai University Faculty of Medicine, Osaka-Sayama, Japan
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16
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Yan Z, Zhou Q, Wang L, Wu J, Zhao Y, Huang G, Peng W, Shen H, Lei J, Yan N. Structure of the Na v1.4-β1 Complex from Electric Eel. Cell 2017; 170:470-482.e11. [PMID: 28735751 DOI: 10.1016/j.cell.2017.06.039] [Citation(s) in RCA: 222] [Impact Index Per Article: 31.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 05/26/2017] [Accepted: 06/23/2017] [Indexed: 02/07/2023]
Abstract
Voltage-gated sodium (Nav) channels initiate and propagate action potentials. Here, we present the cryo-EM structure of EeNav1.4, the Nav channel from electric eel, in complex with the β1 subunit at 4.0 Å resolution. The immunoglobulin domain of β1 docks onto the extracellular L5I and L6IV loops of EeNav1.4 via extensive polar interactions, and the single transmembrane helix interacts with the third voltage-sensing domain (VSDIII). The VSDs exhibit "up" conformations, while the intracellular gate of the pore domain is kept open by a digitonin-like molecule. Structural comparison with closed NavPaS shows that the outward transfer of gating charges is coupled to the iris-like pore domain dilation through intricate force transmissions involving multiple channel segments. The IFM fast inactivation motif on the III-IV linker is plugged into the corner enclosed by the outer S4-S5 and inner S6 segments in repeats III and IV, suggesting a potential allosteric blocking mechanism for fast inactivation.
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Affiliation(s)
- Zhen Yan
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences and School of Medicine, Tsinghua University, Beijing, China; Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Qiang Zhou
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences and School of Medicine, Tsinghua University, Beijing, China; Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Lin Wang
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences and School of Medicine, Tsinghua University, Beijing, China; Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Jianping Wu
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences and School of Medicine, Tsinghua University, Beijing, China; Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Yanyu Zhao
- Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Gaoxingyu Huang
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences and School of Medicine, Tsinghua University, Beijing, China; Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Wei Peng
- Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Huaizong Shen
- Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Jianlin Lei
- Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China; Technology Center for Protein Sciences, Ministry of Education Key Laboratory of Protein Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Nieng Yan
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences and School of Medicine, Tsinghua University, Beijing, China; Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China.
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Structure-based assessment of disease-related mutations in human voltage-gated sodium channels. Protein Cell 2017; 8:401-438. [PMID: 28150151 PMCID: PMC5445024 DOI: 10.1007/s13238-017-0372-z] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Accepted: 01/09/2017] [Indexed: 12/15/2022] Open
Abstract
Voltage-gated sodium (Nav) channels are essential for the rapid upstroke of action potentials and the propagation of electrical signals in nerves and muscles. Defects of Nav channels are associated with a variety of channelopathies. More than 1000 disease-related mutations have been identified in Nav channels, with Nav1.1 and Nav1.5 each harboring more than 400 mutations. Nav channels represent major targets for a wide array of neurotoxins and drugs. Atomic structures of Nav channels are required to understand their function and disease mechanisms. The recently determined atomic structure of the rabbit voltage-gated calcium (Cav) channel Cav1.1 provides a template for homology-based structural modeling of the evolutionarily related Nav channels. In this Resource article, we summarized all the reported disease-related mutations in human Nav channels, generated a homologous model of human Nav1.7, and structurally mapped disease-associated mutations. Before the determination of structures of human Nav channels, the analysis presented here serves as the base framework for mechanistic investigation of Nav channelopathies and for potential structure-based drug discovery.
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Angelopoulou C, Veletza S, Heliopoulos I, Vadikolias K, Tripsianis G, Stathi C, Piperidou C. Association of SCN1A gene polymorphism with antiepileptic drug responsiveness in the population of Thrace, Greece. Arch Med Sci 2017; 13:138-147. [PMID: 28144265 PMCID: PMC5206360 DOI: 10.5114/aoms.2016.59737] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 03/13/2015] [Indexed: 12/14/2022] Open
Abstract
INTRODUCTION The aim was to examine the influence of the SCN1A gene polymorphism IVS5-91 rs3812718 G>A on the response to antiepileptic drugs (AEDs) in monotherapy or polytherapy. MATERIAL AND METHODS Two hundred epilepsy patients and 200 healthy subjects were genotyped for SCN1A IVS5-91 rs3812718 G>A polymorphism using TaqMan assay. Patients were divided into drug-responsive and drug-resistant patients. The drug-responsive group was further studied, comparing monotherapy in maximum and minimum doses and monotherapy-responsive and -resistant groups. RESULTS There were no statistically significant differences in the allelic frequencies and genotype distributions between patients and controls (p = 0.178). The distribution of SCN1A IVS5-91 rs3812718 G>A genotypes was similar between drug-responsive and drug-resistant patients (p = 0.463). The differences in genotype distributions (A/A or A/G vs. G/G) between monotherapy-responsive and -resistant groups were statistically significant (p = 0.021). Within the monotherapy-responsive group, patients with the A/A or A/G genotype needed higher dose AEDs than patients with the G/G genotype (p = 0.032). The relative risk for generalized epilepsy due to A-containing genotypes was of marginal statistical significance when compared with the G/G genotype (p = 0.05). CONCLUSIONS Overall, our findings demonstrate an association of SCN1A IVS5-91 rs3812718 G>A polymorphism with AED responsiveness in monotherapy without evidence of an effect on drug-resistant epilepsy.
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Affiliation(s)
| | - Stavroula Veletza
- Department of Neurology, Democritus University of Thrace, Alexandroupolis, Greece
| | - Ioannis Heliopoulos
- Department of Neurology, Democritus University of Thrace, Alexandroupolis, Greece
| | | | - Grigorios Tripsianis
- Department of Neurology, Democritus University of Thrace, Alexandroupolis, Greece
| | - Chrysa Stathi
- Department of Neurology, Democritus University of Thrace, Alexandroupolis, Greece
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Vatanparast J, Bazleh S, Janahmadi M. The effects of linalool on the excitability of central neurons of snail Caucasotachea atrolabiata. Comp Biochem Physiol C Toxicol Pharmacol 2017; 192:33-39. [PMID: 27939722 DOI: 10.1016/j.cbpc.2016.12.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 12/02/2016] [Accepted: 12/02/2016] [Indexed: 11/17/2022]
Abstract
Linalool is a major constituent of the essential oil of several plant species and possesses several biological activities. In this work, we studied the effects of linalool on excitability of central neurons of land snail Caucasotachea atrolabiata and tried to elucidate the underlying mechanisms. The lower concentration of linalool (0.1mM) showed suppressive action on spontaneous activity and pentylenetetrazole-induced epileptiform activity. These effects were associated with elevation of the action potential threshold and reduction of action potential rising phase, supporting the inhibitory action of linalool on Na+ channels. At this concentration it also prolonged the post stimulus inhibitory period that can take part in its antiepileptic effect and apparently results from increased action potential duration and indirect augmentation of Ca2+-activated K+ currents. At higher concentration, however, linalool (0.4mM) increased the neuronal excitability and induced epileptiform activity. The modulatory effects on action potential waveform during preconvulsive period suggest that the recent effect is mainly dependent on the suppression of outward potassium currents underlying repolarization phase and afterhyperpolarization. The linalool-induced epileptiform activity was abolished by Ca2+ channel blockers, nifedipine and nickel chloride, and selective inhibitor of protein kinase C, chelerythrine, suggesting that Ca2+ inward currents and protein kinase C (PKC) activity are required for linalool-induced epileptiform activity. Our results support the antiepileptic activity of linalool at lower dose, but it shows epileptogenic activity when applied directly on snail neurons at higher dose. Linalool may also be a potential therapeutic agent for activating PKC.
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Affiliation(s)
| | - Sara Bazleh
- Department of Biology, Shiraz University, Shiraz, Iran
| | - Mahyar Janahmadi
- Neuroscience Research Center and Department of Physiology, Medical School, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Dual effects of eugenol on the neuronal excitability: An in vitro study. Neurotoxicology 2016; 58:84-91. [PMID: 27894698 DOI: 10.1016/j.neuro.2016.11.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 11/10/2016] [Accepted: 11/24/2016] [Indexed: 11/23/2022]
Abstract
Besides its well-known actions on sensory afferents, eugenol also affects general excitability of the nervous system, but the mechanisms involved in the recent effect, especially through modulation of ion channels, have received much less attention. In this study, we studied the effects of eugenol on the excitability of central neurons of land snail Caucasotachea atrolabiata and tried to elucidate the underlying ionic mechanisms. The lower concentration of eugenol (0.5mM) reversibly reduced the frequency of spontaneous action potentials that was associated with elevation of threshold, reduction of maximum slope of rising phase and prolongation of actin potentials. These effects were mimicked by riluzole, suggesting that they might be mediated by inhibition of Na+ channels. Eugenol also prolonged the single-spike afterhyperpolarization and post stimulus inhibitory period, but these effects seemed to be consequent to action potential prolongation that indirectly augment Ca2+ inward currents and Ca2+-activated K+ currents. This concentration of eugenol was also able to prevent or abolish pentylenetetrazole-induced epileptiform activity. On the other hand, a higher concentration of eugenol (2mM) reversibly increased the frequency of action potentials and then induced epileptiform activity in majority of treated neurons. Several criteria suggest that the inhibition of K+ channels by higher concentration of eugenol and indirect augmentation of Ca2+ currents are central to the hyperexcitability and epileptiform activity induced by eugenol. Our findings indicate that while low concentration of eugenol could have antiepileptic properties, at higher concentration it induces epileptiform activity. It seems that does dependent inhibition of the ionic currents underlying rising and falling phases of action potential is relevant to the eugenol suppressant and excitatory actions, respectively.
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21
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Lin GW, Lu P, Zeng T, Tang HL, Chen YH, Liu SJ, Gao MM, Zhao QH, Yi YH, Long YS. GAPDH-mediated posttranscriptional regulations of sodium channel Scn1a and Scn3a genes under seizure and ketogenic diet conditions. Neuropharmacology 2016; 113:480-489. [PMID: 27816501 DOI: 10.1016/j.neuropharm.2016.11.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2016] [Revised: 10/28/2016] [Accepted: 11/01/2016] [Indexed: 01/12/2023]
Abstract
Abnormal expressions of sodium channel SCN1A and SCN3A genes alter neural excitability that are believed to contribute to the pathogenesis of epilepsy, a long-term risk of recurrent seizures. Ketogenic diet (KD), a high-fat and low-carbohydrate treatment for difficult-to-control (refractory) epilepsy in children, has been suggested to reverse gene expression patterns. Here, we reveal a novel role of GAPDH on the posttranscriptional regulation of mouse Scn1a and Scn3a expressions under seizure and KD conditions. We show that GAPDH binds to a conserved region in the 3' UTRs of human and mouse SCN1A and SCN3A genes, which decreases and increases genes' expressions by affecting mRNA stability through SCN1A 3' UTR and SCN3A 3' UTR, respectively. In seizure mice, the upregulation and phosphorylation of GAPDH enhance its binding to the 3' UTR, which lead to downregulation of Scn1a and upregulation of Scn3a. Furthermore, administration of KD generates β-hydroxybutyric acid which rescues the abnormal expressions of Scn1a and Scn3a by weakening the GAPDH's binding to the element. Taken together, these data suggest that GAPDH-mediated expression regulation of sodium channel genes may be associated with epilepsy and the anticonvulsant action of KD.
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Affiliation(s)
- Guo-Wang Lin
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou 501260, China
| | - Ping Lu
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou 501260, China
| | - Tao Zeng
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou 501260, China
| | - Hui-Ling Tang
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou 501260, China
| | - Yong-Hong Chen
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou 501260, China
| | - Shu-Jing Liu
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou 501260, China
| | - Mei-Mei Gao
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou 501260, China
| | - Qi-Hua Zhao
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou 501260, China
| | - Yong-Hong Yi
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou 501260, China
| | - Yue-Sheng Long
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou 501260, China.
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Peimine, a main active ingredient of Fritillaria, exhibits anti-inflammatory and pain suppression properties at the cellular level. Fitoterapia 2016; 111:1-6. [DOI: 10.1016/j.fitote.2016.03.018] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 03/22/2016] [Accepted: 03/24/2016] [Indexed: 12/19/2022]
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A Point Mutation in SCN1A 5' Genomic Region Decreases the Promoter Activity and Is Associated with Mild Epilepsy and Seizure Aggravation Induced by Antiepileptic Drug. Mol Neurobiol 2016; 54:2428-2434. [PMID: 26969601 DOI: 10.1007/s12035-016-9800-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 02/16/2016] [Indexed: 01/05/2023]
Abstract
The SCN1A gene with 1274 point mutations in the coding regions or genomic rearrangements is the most clinically relevant epilepsy gene. Recent studies have demonstrated that variations in the noncoding regions are potentially associated with epilepsies, but no distinct mutation has been reported. We sequenced the 5' upstream region of SCN1A in 166 patients with epilepsy and febrile seizures who were negative for point mutations in the coding regions or genomic rearrangements. A heterozygous mutation h1u-1962 T > G was identified in a patient with partial epilepsy and febrile seizures, which was aggravated by oxcarbazepine. This mutation was transmitted from the patient's asymptomatic mother and not found in the 110 normal controls. h1u-1962 T > G was located upstream the most frequently used noncoding exon and within the promoter sequences. Further experiments showed that this mutation decreased the promoter activity by 42.1 % compared with that of the paired haplotype (P < 0.001). In contrast to the null expression that results in haploinsufficiency and severe phenotype, this mutation caused relatively less impairment, explaining the mild epilepsy with incomplete penetrance. The antiepileptic drug-induced seizure aggravation in this patient suggests clinical attention for mutations or variations in noncoding regions that may affect SCN1A expression.
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Heterologous expression of NaV1.9 chimeras in various cell systems. Pflugers Arch 2015; 467:2423-35. [PMID: 25916202 DOI: 10.1007/s00424-015-1709-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Revised: 03/31/2015] [Accepted: 04/16/2015] [Indexed: 01/27/2023]
Abstract
SCN11A encodes the voltage-gated sodium channel NaV1.9, which deviates most strongly from the other eight NaV channels expressed in mammals. It is characterized by resistance to the prototypic NaV channel blocker tetrodotoxin and exhibits slow activation and inactivation gating. Its expression in dorsal root ganglia neurons suggests a role in motor or pain signaling functions as also recently demonstrated by the occurrence of various mutations in human SCN11A leading to altered pain sensation syndromes. The systematic investigation of human NaV1.9, however, is severely hampered because of very poor heterologous expression in host cells. Using patch-clamp and two-electrode voltage-clamp methods, we show that this limitation is caused by the C-terminal structure of NaV1.9. A chimera of NaV1.9 harboring the C terminus of NaV1.4 yields functional expression not only in neuronal cells but also in non-excitable cells, such as HEK 293T or Xenopus oocytes. The major functional difference of the chimeric channel with respect to NaV1.9 is an accelerated activation and inactivation. Since the entire transmembrane domain is preserved, it is suited for studying pharmacological properties of the channel and the functional impact of disease-causing mutations. Moreover, we demonstrate how mutation S360Y makes NaV1.9 channels sensitive to tetrodotoxin and saxitoxin and that the unusual slow open-state inactivation of NaV1.9 is also mediated by the IFM (isoleucine-phenylalanine-methionine) inactivation motif located in the linker connecting domains III and IV.
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Meng H, Xu HQ, Yu L, Lin GW, He N, Su T, Shi YW, Li B, Wang J, Liu XR, Tang B, Long YS, Yi YH, Liao WP. TheSCN1AMutation Database: Updating Information and Analysis of the Relationships among Genotype, Functional Alteration, and Phenotype. Hum Mutat 2015; 36:573-80. [PMID: 25754450 DOI: 10.1002/humu.22782] [Citation(s) in RCA: 136] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Accepted: 02/25/2015] [Indexed: 11/11/2022]
Affiliation(s)
- Heng Meng
- Institute of Neuroscience and The Second Affiliated Hospital of Guangzhou Medical University; Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China; Guangzhou China
- Department of Neurology; The First Affiliated Hospital of Jinan University; Guangzhou China
| | - Hai-Qing Xu
- Institute of Neuroscience and The Second Affiliated Hospital of Guangzhou Medical University; Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China; Guangzhou China
| | - Lu Yu
- Institute of Neuroscience and The Second Affiliated Hospital of Guangzhou Medical University; Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China; Guangzhou China
| | - Guo-Wang Lin
- Institute of Neuroscience and The Second Affiliated Hospital of Guangzhou Medical University; Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China; Guangzhou China
| | - Na He
- Institute of Neuroscience and The Second Affiliated Hospital of Guangzhou Medical University; Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China; Guangzhou China
| | - Tao Su
- Institute of Neuroscience and The Second Affiliated Hospital of Guangzhou Medical University; Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China; Guangzhou China
| | - Yi-Wu Shi
- Institute of Neuroscience and The Second Affiliated Hospital of Guangzhou Medical University; Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China; Guangzhou China
| | - Bin Li
- Institute of Neuroscience and The Second Affiliated Hospital of Guangzhou Medical University; Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China; Guangzhou China
| | - Jie Wang
- Institute of Neuroscience and The Second Affiliated Hospital of Guangzhou Medical University; Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China; Guangzhou China
| | - Xiao-Rong Liu
- Institute of Neuroscience and The Second Affiliated Hospital of Guangzhou Medical University; Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China; Guangzhou China
| | - Bin Tang
- Institute of Neuroscience and The Second Affiliated Hospital of Guangzhou Medical University; Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China; Guangzhou China
| | - Yue-Sheng Long
- Institute of Neuroscience and The Second Affiliated Hospital of Guangzhou Medical University; Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China; Guangzhou China
| | - Yong-Hong Yi
- Institute of Neuroscience and The Second Affiliated Hospital of Guangzhou Medical University; Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China; Guangzhou China
| | - Wei-Ping Liao
- Institute of Neuroscience and The Second Affiliated Hospital of Guangzhou Medical University; Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China; Guangzhou China
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Yang SW, Ho GD, Tulshian D, Bercovici A, Tan Z, Hanisak J, Brumfield S, Matasi J, Sun X, Sakwa SA, Herr RJ, Zhou X, Bridal T, Urban M, Vivian J, Rindgen D, Sorota S. Bioavailable pyrrolo-benzo-1,4-diazines as Nav1.7 sodium channel blockers for the treatment of pain. Bioorg Med Chem Lett 2014; 24:4958-62. [DOI: 10.1016/j.bmcl.2014.09.038] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Revised: 09/09/2014] [Accepted: 09/11/2014] [Indexed: 11/16/2022]
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27
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Ho GD, Tulshian D, Bercovici A, Tan Z, Hanisak J, Brumfield S, Matasi J, Heap CR, Earley WG, Courneya B, Jason Herr R, Zhou X, Bridal T, Rindgen D, Sorota S, Yang SW. Discovery of pyrrolo-benzo-1,4-diazines as potent Nav1.7 sodium channel blockers. Bioorg Med Chem Lett 2014; 24:4110-3. [DOI: 10.1016/j.bmcl.2014.07.060] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Revised: 07/17/2014] [Accepted: 07/21/2014] [Indexed: 02/06/2023]
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Schmunk G, Gargus JJ. Channelopathy pathogenesis in autism spectrum disorders. Front Genet 2013; 4:222. [PMID: 24204377 PMCID: PMC3817418 DOI: 10.3389/fgene.2013.00222] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2013] [Accepted: 10/09/2013] [Indexed: 01/12/2023] Open
Abstract
Autism spectrum disorder (ASD) is a syndrome that affects normal brain development and is characterized by impaired social interaction as well as verbal and non-verbal communication and by repetitive, stereotypic behavior. ASD is a complex disorder arising from a combination of multiple genetic and environmental factors that are independent from racial, ethnic and socioeconomical status. The high heritability of ASD suggests a strong genetic basis for the disorder. Furthermore, a mounting body of evidence implies a role of various ion channel gene defects (channelopathies) in the pathogenesis of autism. Indeed, recent genome-wide association, and whole exome- and whole-genome resequencing studies linked polymorphisms and rare variants in calcium, sodium and potassium channels and their subunits with susceptibility to ASD, much as they do with bipolar disorder, schizophrenia and other neuropsychiatric disorders. Moreover, animal models with these genetic variations recapitulate endophenotypes considered to be correlates of autistic behavior seen in patients. An ion flux across the membrane regulates a variety of cell functions, from generation of action potentials to gene expression and cell morphology, thus it is not surprising that channelopathies have profound effects on brain functions. In the present work, we summarize existing evidence for the role of ion channel gene defects in the pathogenesis of autism with a focus on calcium signaling and its downstream effects.
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Affiliation(s)
- Galina Schmunk
- Department of Physiology and Biophysics, University of California Irvine, CA, USA ; UCI Center for Autism Research and Treatment, School of Medicine, University of California Irvine, CA, USA
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The voltage-gated sodium channel nav1.8 is expressed in human sperm. PLoS One 2013; 8:e76084. [PMID: 24086692 PMCID: PMC3785426 DOI: 10.1371/journal.pone.0076084] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Accepted: 08/20/2013] [Indexed: 12/15/2022] Open
Abstract
The role of Na(+) fluxes through voltage-gated sodium channels in the regulation of sperm cell function remains poorly understood. Previously, we reported that several genes encoding voltage-gated Na(+) channels were expressed in human testis and mature spermatozoa. In this study, we analyzed the presence and function of the TTX-resistant VGSC α subunit Nav1.8 in human capacitated sperm cells. Using an RT-PCR assay, we found that the mRNA of the gene SCN10A, that encode Na v1.8, was abundantly and specifically expressed in human testis and ejaculated spermatozoa. The Na v1.8 protein was detected in capacitated sperm cells using three different specific antibodies against this channel. Positive immunoreactivity was mainly located in the neck and the principal piece of the flagellum. The presence of Na v1.8 in sperm cells was confirmed by Western blot. Functional studies demonstrated that the increases in progressive motility produced by veratridine, a voltage-gated sodium channel activator, were reduced in sperm cells preincubated with TTX (10 μM), the Na v1.8 antagonist A-803467, or a specific Na v1.8 antibody. Veratridine elicited similar percentage increases in progressive motility in sperm cells maintained in Ca(2+)-containing or Ca(2+)-free solution and did not induce hyperactivation or the acrosome reaction. Veratridine caused a rise in sperm intracellular Na(+), [Na(+)]i, and the sustained phase of the response was inhibited in the presence of A-803467. These results verify that the Na(+) channel Na v1.8 is present in human sperm cells and demonstrate that this channel participates in the regulation of sperm function.
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Abstract
Carbamazepine (CBZ) blocks neuronal sodium channels in a voltage- and frequency-dependent manner, delaying the recovery of the channels from the inactivated state, reducing the number of action potentials within a burst, and decreasing burst duration. The α-subunit of the first neuronal sodium channel (SCN1A) is a major gene in different epilepsies. A synonymous polymorphism (SCN1A IVS5N + 5 G>A or rs3812718) is common in exon 5 of this gene. Mutations in the α-unit of this gene are associated with CBZ-resistant epilepsy and a higher maintenance dose of CBZ. We have investigated the association of this single nucleotide polymorphism (SNP) and epilepsy, efficacy and dose-dependence of CBZ therapy in 147 adult Macedonian patients and 137 non epileptic controls. No significant differences in allelic frequencies and genotype distribution were found between patients and controls (p = 0.94278), or between CBZ-responsive and unresponsive patients (p = 0.55449). An association between the A allele and a higher maintenance dose in CBZ-responsive patients was detected. No statistical difference was found between the plasma levels of CBZ and genotype of patients receiving the same dose, indicating that the variant exerts its effect at the level of receptor responsiveness. The predictive value of pretreatment testing showed a minor insignificant difference between patients with different genotypes, primarily due to a small number of patients.
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31
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Nardi A, Damann N, Hertrampf T, Kless A. Advances in targeting voltage-gated sodium channels with small molecules. ChemMedChem 2012; 7:1712-40. [PMID: 22945552 DOI: 10.1002/cmdc.201200298] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2012] [Revised: 07/30/2012] [Indexed: 12/19/2022]
Abstract
Blockade of voltage-gated sodium channels (VGSCs) has been used successfully in the clinic to enable control of pathological firing patterns that occur in conditions as diverse as chronic pain, epilepsy, and arrhythmias. Herein we review the state of the art in marketed sodium channel inhibitors, including a brief compendium of their binding sites and of the cellular and molecular biology of sodium channels. Despite the preferential action of this drug class toward over-excited cells, which significantly limits potential undesired side effects on other cells, the need to develop a second generation of sodium channel inhibitors to overcome their critical clinical shortcomings is apparent. Current approaches in drug discovery to deliver novel and truly innovative sodium channel inhibitors is next presented by surveying the most recent medicinal chemistry breakthroughs in the field of small molecules and developments in automated patch-clamp platforms. Various strategies aimed at identifying small molecules that target either particular isoforms of sodium channels involved in specific diseases or anomalous sodium channel currents, irrespective of the isoform by which they have been generated, are critically discussed and revised.
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Affiliation(s)
- Antonio Nardi
- Global Drug Discovery, Department of Medicinal Chemistry, Grünenthal, Zieglerstrasse 6, 52078 Aachen, Germany.
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32
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Yoshinaka-Niitsu A, Yamagaki T, Harada M, Tachibana K. Solution NMR analysis of the binding mechanism of DIVS6 model peptides of voltage-gated sodium channels and the lipid soluble alkaloid veratridine. Bioorg Med Chem 2012; 20:2796-802. [PMID: 22483840 DOI: 10.1016/j.bmc.2012.03.034] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Revised: 03/14/2012] [Accepted: 03/15/2012] [Indexed: 10/28/2022]
Abstract
Voltage-gated sodium channels (VGSCs) are responsible for generating action potentials in nervous systems. Veratridine (VTD), a lipid soluble alkaloid isolated from sabadilla lily seed, is believed to bind to segment 6 of VGSCs and act as a partial agonist. However, high resolution structural interaction mechanism between VGSCs and VTD is difficult to elucidate because of the large size and membrane localization of VGSCs. Here, the authors designed model peptides corresponding to domain IV segment 6 (DIVS6) of rat skeletal muscle Na(v)1.4 and analyzed the complex of the model peptides and VTD by solution NMR analysis to obtain structural information of the interaction. The model peptides successfully formed an α-helices, which is the suspected native conformation of DIVS6, in aqueous 2,2,2-trifluoroethanol, a membrane-mimicking solvent. The VTD binding residues of the model peptide were identified using the NMR titration experiments with VTD, including a newly discovered VTD binding residue Leu14 (μ1-L1580 in Na(v)1.4), which has not been reported by point mutation studies. Mapping of VTD binding residues on the model peptide revealed the hydrophobic interaction surface. NMR titration experiments with a non-toxic analog of VTD, veracevine, also indicated that the steroidal backbone of VTD interacts with the hydrophobic interaction surface of DIVS6 and that the 3-acyl group of VTD possibly causes neurotoxicity by interacting with domain I segment 6 and/or domain IV segment 4.
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Affiliation(s)
- Ai Yoshinaka-Niitsu
- Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan
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33
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Lack of association of SCN2A and KCNJ10 polymorphisms in Korean children with epilepsy: intractability and relapse of epilepsy. Mol Cell Toxicol 2012. [DOI: 10.1007/s13273-012-0008-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Ren CT, Li DM, Ou SW, Wang YJ, Lin Y, Zong ZH, Kameyama M, Kameyama A. Cloning and expression of the two new variants of Nav1.5/SCN5A in rat brain. Mol Cell Biochem 2012; 365:139-48. [PMID: 22331407 DOI: 10.1007/s11010-012-1253-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2011] [Accepted: 01/13/2012] [Indexed: 12/19/2022]
Abstract
The α-subunit of tetrodotoxin-resistant (TTX-R) voltage-gated sodium channel (VSGC, Nav1.5/SCN5A) has been found from the rat heart and human neuroblastoma cell line NB-1, but its expression in rat brain has not been identified radically. In this study, a reverse transcriptase-polymerase chain reaction was used to clone the full sequence of Nav1.5 (designated as rN1) α-subunit in rat brain and compared the distribution in different lobe of brain in different developmental stages. The open reading frame of rN1 encodes 2,016 amino acid residues and sequence analysis indicated that rN1 is highly homologous with 96.53% amino acids identity to rat cardiac Nav1.5 (rH1) and 96.13% amino acids identity to human neuroblastoma Nav1.5 (hNbR1). It has all the structural features of a VSGC and the presence of a cysteine residue (C373) in the pore loop region of domain I suggests that this channel is resistant to TTX. A new exon (exon6A) that is distinct from rH1 was found in DI-S3-S4, meanwhile an isomer of alternative splicing that deleted 53 amino acids (exon18) was found for the first time in domain DII-III in rN1. (designated as rN1-2). Distribution results demonstrated that rN1 expressed discrepancy in different ages and lobe in brain. The expression level of rN1 was gradually more stable in adult than in neonatal; these results suggest that rN1 has a newly identified exon for alternative splicing that is differentfrom rat heart and is more widely expressed in rat brain than previously thought.
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Affiliation(s)
- Cheng-Tao Ren
- Department of Neurosurgery, The Affiliated Municipal Hospital, Medical College, Qingdao University, Qingdao, China
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Ancient origin of four-domain voltage-gated Na+ channels predates the divergence of animals and fungi. J Membr Biol 2012; 245:117-23. [PMID: 22258316 DOI: 10.1007/s00232-012-9415-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2011] [Accepted: 01/03/2012] [Indexed: 12/19/2022]
Abstract
The four-domain voltage-gated Na(+) channels are believed to have arisen in multicellular animals, possibly during the evolution of the nervous system. Recent genomic studies reveal that many ion channels, including Na(+) channels and Ca(2+) channels previously thought to be restricted to animals, can be traced back to one of the unicellular ancestors of animals, Monosiga brevicollis. The eukaryotic supergroup Opisthokonta contains animals, fungi, and a diverse group of their unicellular relatives including M. brevicollis. Here, we demonstrate the presence of a putative voltage-gated Na(+) channel homolog (TtrNa(V)) in the apusozoan protist Thecamonas trahens, which belongs to the unicellular sister group to Opisthokonta. TtrNa(V) displays a unique selectivity motif distinct from most animal voltage-gated Na(+) channels. The identification of TtrNa(V) suggests that voltage-gated Na(+) channels might have evolved before the divergence of animals and fungi. Furthermore, our analyses reveal that Na(V) channels have been lost independently in the amoeboid holozoan Capsaspora owczarzaki of the animal lineage and in several basal fungi. These findings provide novel insights into the evolution of four-domain voltage-gated ion channels, ion selectivity, and membrane excitability in the Opisthokonta lineage.
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Vornanen M, Hassinen M, Haverinen J. Tetrodotoxin sensitivity of the vertebrate cardiac Na+ current. Mar Drugs 2011; 9:2409-2422. [PMID: 22163193 PMCID: PMC3229242 DOI: 10.3390/md9112409] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Revised: 11/02/2011] [Accepted: 11/10/2011] [Indexed: 01/20/2023] Open
Abstract
Evolutionary origin and physiological significance of the tetrodotoxin (TTX) resistance of the vertebrate cardiac Na+ current (INa) is still unresolved. To this end, TTX sensitivity of the cardiac INa was examined in cardiac myocytes of a cyclostome (lamprey), three teleost fishes (crucian carp, burbot and rainbow trout), a clawed frog, a snake (viper) and a bird (quail). In lamprey, teleost fishes, frog and bird the cardiac INa was highly TTX-sensitive with EC50-values between 1.4 and 6.6 nmol·L−1. In the snake heart, about 80% of the INa was TTX-resistant with EC50 value of 0.65 μmol·L−1, the rest being TTX-sensitive (EC50 = 0.5 nmol·L−1). Although TTX-resistance of the cardiac INa appears to be limited to mammals and reptiles, the presence of TTX-resistant isoform of Na+ channel in the lamprey heart suggest an early evolutionary origin of the TTX-resistance, perhaps in the common ancestor of all vertebrates.
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Affiliation(s)
- Matti Vornanen
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +358-13-2513-383; Fax: +358-13-2513-590
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37
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O'Brien JE, Drews VL, Jones JM, Dugas JC, Barres BA, Meisler MH. Rbfox proteins regulate alternative splicing of neuronal sodium channel SCN8A. Mol Cell Neurosci 2011; 49:120-6. [PMID: 22044765 DOI: 10.1016/j.mcn.2011.10.005] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2011] [Revised: 10/10/2011] [Accepted: 10/14/2011] [Indexed: 12/17/2022] Open
Abstract
The SCN8A gene encodes the voltage-gated sodium channel Na(v)1.6, a major channel in neurons of the CNS and PNS. SCN8A contains two alternative exons,18N and 18A, that exhibit tissue specific splicing. In brain, the major SCN8A transcript contains exon 18A and encodes the full-length sodium channel. In other tissues, the major transcript contains exon 18N and encodes a truncated protein, due to the presence of an in-frame stop codon. Selection of exon 18A is therefore essential for generation of a functional channel protein, but the proteins involved in this selection have not been identified. Using a 2.6 kb Scn8a minigene containing exons 18N and 18A, we demonstrate that co-transfection with Fox-1 or Fox-2 initiates inclusion of exon 18A. This effect is dependent on the consensus Fox binding site located 28 bp downstream of exon 18A. We examined the alternative splicing of human SCN8A and found that the postnatal switch to exon 18A is completed later than 10 months of age. In purified cell populations, transcripts containing exon 18A predominate in neurons but are not present in oligodendrocytes or astrocytes. Transcripts containing exon 18N appear to be degraded by nonsense-mediated decay in HEK cells. Our data indicate that RBFOX proteins contribute to the cell-specific expression of Na(v)1.6 channels in mature neurons.
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Affiliation(s)
- Janelle E O'Brien
- Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109-5618, USA
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38
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Papassotiropoulos A, Henke K, Stefanova E, Aerni A, Müller A, Demougin P, Vogler C, Sigmund JC, Gschwind L, Huynh KD, Coluccia D, Mondadori CR, Hänggi J, Buchmann A, Kostic V, Novakovic I, van den Bussche H, Kaduszkiewicz H, Weyerer S, Bickel H, Riedel-Heller S, Pentzek M, Wiese B, Dichgans M, Wagner M, Jessen F, Maier W, de Quervain DJF. A genome-wide survey of human short-term memory. Mol Psychiatry 2011; 16:184-92. [PMID: 20038948 PMCID: PMC3030750 DOI: 10.1038/mp.2009.133] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Recent advances in the development of high-throughput genotyping platforms allow for the unbiased identification of genes and genomic sequences related to heritable traits. In this study, we analyzed human short-term memory, which refers to the ability to remember information over a brief period of time and which has been found disturbed in many neuropsychiatric conditions, including schizophrenia and depression. We performed a genome-wide survey at 909 622 polymorphic loci and report six genetic variations significantly associated with human short-term memory performance after genome-wide correction for multiple comparisons. A polymorphism within SCN1A (encoding the α subunit of the type I voltage-gated sodium channel) was replicated in three independent populations of 1699 individuals. Functional magnetic resonance imaging during an n-back working memory task detected SCN1A allele-dependent activation differences in brain regions typically involved in working memory processes. These results suggest an important role for SCN1A in human short-term memory.
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Affiliation(s)
- A Papassotiropoulos
- Division of Molecular Psychology, University of Basel, Basel, Switzerland. or
| | - K Henke
- Department of Psychology, University of Bern, Bern, Switzerland
| | - E Stefanova
- Institute of Neurology, CCS, School of Medicine, University of Belgrade, Belgrade, Serbia
| | - A Aerni
- Division of Cognitive Neuroscience, University of Basel, Basel, Switzerland
| | - A Müller
- Division of Molecular Psychology, University of Basel, Basel, Switzerland,Life Sciences Training Facility, Biozentrum, University of Basel, Basel, Switzerland
| | - P Demougin
- Division of Molecular Psychology, University of Basel, Basel, Switzerland,Life Sciences Training Facility, Biozentrum, University of Basel, Basel, Switzerland
| | - C Vogler
- Division of Molecular Psychology, University of Basel, Basel, Switzerland,Life Sciences Training Facility, Biozentrum, University of Basel, Basel, Switzerland
| | - J C Sigmund
- Division of Molecular Psychology, University of Basel, Basel, Switzerland,Life Sciences Training Facility, Biozentrum, University of Basel, Basel, Switzerland
| | - L Gschwind
- Division of Molecular Psychology, University of Basel, Basel, Switzerland,Life Sciences Training Facility, Biozentrum, University of Basel, Basel, Switzerland
| | - K-D Huynh
- Division of Molecular Psychology, University of Basel, Basel, Switzerland,Life Sciences Training Facility, Biozentrum, University of Basel, Basel, Switzerland
| | - D Coluccia
- Division of Psychiatry Research, University of Zurich, Zurich, Switzerland
| | - C R Mondadori
- Division of Neuropsychology, Department of Neurology, University Hospital Zurich, Zurich, Switzerland
| | - J Hänggi
- Division of Neuropsychology, Institute of Psychology, University of Zurich, Zurich, Switzerland
| | - A Buchmann
- Division of Psychiatry Research, University of Zurich, Zurich, Switzerland
| | - V Kostic
- Institute of Neurology, CCS, School of Medicine, University of Belgrade, Belgrade, Serbia
| | - I Novakovic
- Institute of Biology, School of Medicine, University of Belgrade, Belgrade, Serbia
| | - H van den Bussche
- Institute of Primary Medical Care, University Medical Center, Hamburg-Eppendorf, Germany
| | - H Kaduszkiewicz
- Institute of Primary Medical Care, University Medical Center, Hamburg-Eppendorf, Germany
| | - S Weyerer
- Central Institute of Mental Health, Mannheim, Germany
| | - H Bickel
- Department of Psychiatry, Technical University of Munich, Munich, Germany
| | - S Riedel-Heller
- Public Mental Health Research Unit, Department of Psychiatry, University of Leipzig, Leipzig, Germany
| | - M Pentzek
- Department of General Practice, Dusseldorf University Medical Center, Dusseldorf, Germany
| | - B Wiese
- Institute for Biometrics, Hannover Medical School, Hannover, Germany
| | - M Dichgans
- Department of Neurology, Klinikum Großhadern, Ludwig-Maximilians University, Munich, Germany
| | - M Wagner
- Department of Psychiatry, University of Bonn, Bonn, Germany
| | - F Jessen
- Department of Psychiatry, University of Bonn, Bonn, Germany
| | - W Maier
- Department of Psychiatry, University of Bonn, Bonn, Germany
| | - D J-F de Quervain
- Division of Cognitive Neuroscience, University of Basel, Basel, Switzerland,Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland,Division of Cognitive Neuroscience, University of Basel, Birmannsgasse 8, Basel 4055, Switzerland. E-mail:
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Firth AL, Remillard CV, Platoshyn O, Fantozzi I, Ko EA, Yuan JXJ. Functional ion channels in human pulmonary artery smooth muscle cells: Voltage-dependent cation channels. Pulm Circ 2011; 1:48-71. [PMID: 21927714 PMCID: PMC3173772 DOI: 10.4103/2045-8932.78103] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The activity of voltage-gated ion channels is critical for the maintenance of cellular membrane potential and generation of action potentials. In turn, membrane potential regulates cellular ion homeostasis, triggering the opening and closing of ion channels in the plasma membrane and, thus, enabling ion transport across the membrane. Such transmembrane ion fluxes are important for excitation–contraction coupling in pulmonary artery smooth muscle cells (PASMC). Families of voltage-dependent cation channels known to be present in PASMC include voltage-gated K+ (Kv) channels, voltage-dependent Ca2+-activated K+ (Kca) channels, L- and T- type voltage-dependent Ca2+ channels, voltage-gated Na+ channels and voltage-gated proton channels. When cells are dialyzed with Ca2+-free K+- solutions, depolarization elicits four components of 4-aminopyridine (4-AP)-sensitive Kvcurrents based on the kinetics of current activation and inactivation. In cell-attached membrane patches, depolarization elicits a wide range of single-channel K+ currents, with conductances ranging between 6 and 290 pS. Macroscopic 4-AP-sensitive Kv currents and iberiotoxin-sensitive Kca currents are also observed. Transcripts of (a) two Na+ channel α-subunit genes (SCN5A and SCN6A), (b) six Ca2+ channel α–subunit genes (α1A, α1B, α1X, α1D, α1Eand α1G) and many regulatory subunits (α2δ1, β1-4, and γ6), (c) 22 Kv channel α–subunit genes (Kv1.1 - Kv1.7, Kv1.10, Kv2.1, Kv3.1, Kv3.3, Kv3.4, Kv4.1, Kv4.2, Kv5.1, Kv 6.1-Kv6.3, Kv9.1, Kv9.3, Kv10.1 and Kv11.1) and three Kv channel β-subunit genes (Kvβ1-3) and (d) four Kca channel α–subunit genes (Sloα1 and SK2-SK4) and four Kca channel β-subunit genes (Kcaβ1-4) have been detected in PASMC. Tetrodotoxin-sensitive and rapidly inactivating Na+ currents have been recorded with properties similar to those in cardiac myocytes. In the presence of 20 mM external Ca2+, membrane depolarization from a holding potential of -100 mV elicits a rapidly inactivating T-type Ca2+ current, while depolarization from a holding potential of -70 mV elicits a slowly inactivating dihydropyridine-sensitive L-type Ca2+ current. This review will focus on describing the electrophysiological properties and molecular identities of these voltage-dependent cation channels in PASMC and their contribution to the regulation of pulmonary vascular function and its potential role in the pathogenesis of pulmonary vascular disease.
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Affiliation(s)
- Amy L Firth
- The Salk Institute for Biological Studies, La Jolla, California, USA
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40
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Zakon HH, Jost MC, Lu Y. Expansion of voltage-dependent Na+ channel gene family in early tetrapods coincided with the emergence of terrestriality and increased brain complexity. Mol Biol Evol 2010; 28:1415-24. [PMID: 21148285 DOI: 10.1093/molbev/msq325] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Mammals have ten voltage-dependent sodium (Nav) channel genes. Nav channels are expressed in different cell types with different subcellular distributions and are critical for many aspects of neuronal processing. The last common ancestor of teleosts and tetrapods had four Nav channel genes, presumably on four different chromosomes. In the lineage leading to mammals, a series of tandem duplications on two of these chromosomes more than doubled the number of Nav channel genes. It is unknown when these duplications occurred and whether they occurred against a backdrop of duplication of flanking genes on their chromosomes or as an expansion of ion channel genes in general. We estimated key dates of the Nav channel gene family expansion by phylogenetic analysis using teleost, elasmobranch, lungfish, amphibian, avian, lizard, and mammalian Nav channel sequences, as well as chromosomal synteny for tetrapod genes. We tested, and exclude, the null hypothesis that Nav channel genes reside in regions of chromosomes prone to duplication by demonstrating the lack of duplication or duplicate retention of surrounding genes. We also find no comparable expansion in other voltage-dependent ion channel gene families of tetrapods following the teleost-tetrapod divergence. We posit a specific expansion of the Nav channel gene family in the Devonian and Carboniferous periods when tetrapods evolved, diversified, and invaded the terrestrial habitat. During this time, the amniote forebrain evolved greater anatomical complexity and novel tactile sensory receptors appeared. The duplication of Nav channel genes allowed for greater regional specialization in Nav channel expression, variation in subcellular localization, and enhanced processing of somatosensory input.
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41
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Feldman CR, Brodie ED, Brodie ED, Pfrender ME. Genetic architecture of a feeding adaptation: garter snake (Thamnophis) resistance to tetrodotoxin bearing prey. Proc Biol Sci 2010; 277:3317-25. [PMID: 20522513 PMCID: PMC2981930 DOI: 10.1098/rspb.2010.0748] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2010] [Accepted: 05/14/2010] [Indexed: 11/12/2022] Open
Abstract
Detailing the genetic basis of adaptive variation in natural populations is a first step towards understanding the process of adaptive evolution, yet few ecologically relevant traits have been characterized at the genetic level in wild populations. Traits that mediate coevolutionary interactions between species are ideal for studying adaptation because of the intensity of selection and the well-characterized ecological context. We have previously described the ecological context, evolutionary history and partial genetic basis of tetrodotoxin (TTX) resistance in garter snakes (Thamnophis). Derived mutations in a voltage-gated sodium channel gene (Na(v)1.4) in three garter snake species are associated with resistance to TTX, the lethal neurotoxin found in their newt prey (Taricha). Here we evaluate the contribution of Na(v)1.4 alleles to TTX resistance in two of those species from central coastal California. We measured the phenotypes (TTX resistance) and genotypes (Na(v)1.4 and microsatellites) in a local sample of Thamnophis atratus and Thamnophis sirtalis. Allelic variation in Na(v)1.4 explains 23 per cent of the variation in TTX resistance in T. atratus while variation in a haphazard sample of the genome (neutral microsatellite markers) shows no association with the phenotype. Similarly, allelic variation in Na(v)1.4 correlates almost perfectly with TTX resistance in T. sirtalis, but neutral variation does not. These strong correlations suggest that Na(v)1.4 is a major effect locus. The simple genetic architecture of TTX resistance in garter snakes may significantly impact the dynamics of phenotypic coevolution. Fixation of a few alleles of major effect in some garter snake populations may have led to the evolution of extreme phenotypes and an 'escape' from the arms race with newts.
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Affiliation(s)
- Chris R Feldman
- Department of Natural Resources and Environmental Sciences, University of Nevada, Reno, NV 89557, USA.
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Widmark J, Sundstrom G, Ocampo Daza D, Larhammar D. Differential Evolution of Voltage-Gated Sodium Channels in Tetrapods and Teleost Fishes. Mol Biol Evol 2010; 28:859-71. [DOI: 10.1093/molbev/msq257] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
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Novel mutation of SCN1A in familial generalized epilepsy with febrile seizures plus. Neurosci Lett 2010; 480:211-4. [PMID: 20600615 DOI: 10.1016/j.neulet.2010.06.040] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2010] [Revised: 06/11/2010] [Accepted: 06/12/2010] [Indexed: 11/23/2022]
Abstract
Generalized epilepsy with febrile seizures plus (GEFS+) is an epileptic syndrome inherited in autosomal dominant mode. Of all the identified causative GEFS+ genes, voltage-gated sodium channel alpha1 subunit gene (SCN1A) is the most clinically relevant one. We describe here the clinical and molecular characterization of a GEFS+ family. A novel heterozygous mutation c.5383G>A was revealed by direct sequencing of the SCN1A gene for both affected and unaffected individuals. It is speculated that the function of the sodium channel could be compromised by the substitution of lysine for a highly conserved residue glutamic acid at position 1795 within the C-terminus of alpha1 subunit. Our finding extends the spectrum of SCN1A mutations related to GEFS+ and further confirms the contribution of the sodium channel genes to the etiology of idiopathic epilepsies.
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Lin CF, Mount SM, Jarmołowski A, Makałowski W. Evolutionary dynamics of U12-type spliceosomal introns. BMC Evol Biol 2010; 10:47. [PMID: 20163699 PMCID: PMC2831892 DOI: 10.1186/1471-2148-10-47] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2009] [Accepted: 02/17/2010] [Indexed: 02/05/2023] Open
Abstract
Background Many multicellular eukaryotes have two types of spliceosomes for the removal of introns from messenger RNA precursors. The major (U2) spliceosome processes the vast majority of introns, referred to as U2-type introns, while the minor (U12) spliceosome removes a small fraction (less than 0.5%) of introns, referred to as U12-type introns. U12-type introns have distinct sequence elements and usually occur together in genes with U2-type introns. A phylogenetic distribution of U12-type introns shows that the minor splicing pathway appeared very early in eukaryotic evolution and has been lost repeatedly. Results We have investigated the evolution of U12-type introns among eighteen metazoan genomes by analyzing orthologous U12-type intron clusters. Examination of gain, loss, and type switching shows that intron type is remarkably conserved among vertebrates. Among 180 intron clusters, only eight show intron loss in any vertebrate species and only five show conversion between the U12 and the U2-type. Although there are only nineteen U12-type introns in Drosophila melanogaster, we found one case of U2 to U12-type conversion, apparently mediated by the activation of cryptic U12 splice sites early in the dipteran lineage. Overall, loss of U12-type introns is more common than conversion to U2-type and the U12 to U2 conversion occurs more frequently among introns of the GT-AG subtype than among introns of the AT-AC subtype. We also found support for natural U12-type introns with non-canonical terminal dinucleotides (CT-AC, GG-AG, and GA-AG) that have not been previously reported. Conclusions Although complete loss of the U12-type spliceosome has occurred repeatedly, U12 introns are extremely stable in some taxa, including eutheria. Loss of U12 introns or the genes containing them is more common than conversion to the U2-type. The degeneracy of U12-type terminal dinucleotides among natural U12-type introns is higher than previously thought.
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Affiliation(s)
- Chiao-Feng Lin
- Institute of Bioinformatics, University of Muenster, Muenster, Germany
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Onkal R, Djamgoz MB. Molecular pharmacology of voltage-gated sodium channel expression in metastatic disease: Clinical potential of neonatal Nav1.5 in breast cancer. Eur J Pharmacol 2009; 625:206-19. [DOI: 10.1016/j.ejphar.2009.08.040] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2009] [Revised: 08/04/2009] [Accepted: 08/19/2009] [Indexed: 10/20/2022]
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Djadid ND, Jazayeri H, Gholizadeh S, Rad SP, Zakeri S. First record of a new member of Anopheles Hyrcanus Group from Iran: molecular identification, diagnosis, phylogeny, status of kdr resistance and Plasmodium infection. JOURNAL OF MEDICAL ENTOMOLOGY 2009; 46:1084-1093. [PMID: 19769039 DOI: 10.1603/033.046.0515] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The current study aimed to provide further evidence on the status of species composition, insecticide resistance, and vectorial capacity within the members of Anopheles (Anopheles) Hyrcanus Group in Ardebil, Giulan, and Khuzestan provinces of Iran. Sequencing the internal transcribed spacer 2 (ITS2) of ribosomal DNA gene led to identification of two members of Hyrcanus complex: Anopheles hyrcanus Pallas and a new species/form, hereafter called Anopheles hyrcanus sp(IR) as a world record. Furthermore, we identified and compared partial sequences of exons I and II and the whole intron I region of insecticide resistance-related voltage-gated sodium channel (vgsc) gene in populations of Hyrcanus Group and other main old world Anopheles species. The ITS2 and vgsc sequences in members of Hyrcanus Group and other Anopheles species were used for construction of phylogenetic tree, which demonstrated the evolutionary relatedness among Western and Eastern Palearctic taxa within the Hyrcanus Group. A nested polymerase chain reaction assay for detection of Plasmodium species revealed the infection of Plasmodium falciparum within An. hyrcanus collected from Fooman district in Guilan province. The data from this study led to the introduction of a new member/form within the Hyrcanus Group, identification and definition of the status of knockdown resistance related to pyrethroids and DDT in their vgsc gene, detection of Plasmodium infection, and further evidence on genetic relatedness within these taxa. The overall results may suggest reconsidering the role ofAn. hyrcanus in malaria transmission, which would be useful for implementation and evaluation of malaria control programs in Western Palearctic region.
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Affiliation(s)
- N Dinparast Djadid
- Malaria and Vector Research Group, Biotechnology Research Center (BRC), Pasteur Institute of Iran, P.O. Box 1316943551, Tehran, Iran.
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Pinto FM, Ravina CG, Fernández-Sánchez M, Gallardo-Castro M, Cejudo-Román A, Candenas L. Molecular and functional characterization of voltage-gated sodium channels in human sperm. Reprod Biol Endocrinol 2009; 7:71. [PMID: 19607678 PMCID: PMC2724540 DOI: 10.1186/1477-7827-7-71] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2009] [Accepted: 07/16/2009] [Indexed: 01/26/2023] Open
Abstract
BACKGROUND We have investigated the expression of voltage-gated sodium channels in human spermatozoa and characterized their role in sperm motility. METHODS Freshly ejaculated semen was collected from thirty normozoospermic human donors, with each donor supplying 2 different samples. Reverse transcription-polymerase chain reaction (RT-PCR) and immunofluorescence techniques were used to detect the mRNAs and proteins of interest. Sperm motility was measured by a computer-assisted sperm analysis system (CASA). Cytosolic free calcium was determined by fluorimetry in cells loaded with the fluorescent calcium indicator Fura-2. RESULTS The mRNAs that encode the different Nav alpha subunits (Nav1.1-1.9) were all expressed in capacitated human spermatozoa. The mRNAs of the auxiliary subunits beta1, beta3 and beta4 were also present. Immunofluorescence studies showed that, with the exception of Nav1.1 and Nav1.3, the Nav channel proteins were present in sperm cells and show specific and different sites of localization. Veratridine, a voltage-gated sodium channel activator, caused time- and concentration-dependent increases in progressive sperm motility. In sperm suspensions loaded with Fura-2, veratridine did not modify intracellular free calcium levels. CONCLUSION This research shows the presence of voltage-gated sodium channels in human sperm and supports a role for these channels in the regulation of mature sperm function.
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Affiliation(s)
- Francisco M Pinto
- Instituto de Investigaciones Químicas, CSIC, Avda. Americo Vespucio 49, 41092 Sevilla, Spain
| | | | | | - Manuel Gallardo-Castro
- Instituto de Investigaciones Químicas, CSIC, Avda. Americo Vespucio 49, 41092 Sevilla, Spain
| | - Antonio Cejudo-Román
- Instituto de Investigaciones Químicas, CSIC, Avda. Americo Vespucio 49, 41092 Sevilla, Spain
| | - Luz Candenas
- Instituto de Investigaciones Químicas, CSIC, Avda. Americo Vespucio 49, 41092 Sevilla, Spain
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Chen K, Godfrey DA, Ilyas O, Xu J, Preston TW. Cerebellum-related characteristics of Scn8a-mutant mice. THE CEREBELLUM 2009; 8:192-201. [PMID: 19424768 DOI: 10.1007/s12311-009-0110-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2008] [Accepted: 04/22/2009] [Indexed: 12/19/2022]
Abstract
Among ten sodium channel alpha-subunit genes mapped in human and mouse genomes, the SCN8A gene is primarily expressed in neurons and glia. Mice with two types of Scn8a null mutations--Scn8a ( med ) and Scn8a ( medTg )--live for only 21-24 days, but those with incomplete mutations-Scn8a ( medJ ) and Scn8a ( medJo )--and those with knockout of Scn8a only in cerebellar Purkinje cells live to adult age. We review here previous work on cerebellum and related regions of Scn8a mutant mice and include some newer immunohistochemical and microchemical results. The resurgent sodium current that underlies the repeated firing of Purkinje cells is reduced in Scn8a mutant and knockout mice. Purkinje cells of mutant mice have greatly reduced spontaneous activity, as do the analogous cartwheel cells of the dorsal cochlear nucleus. Up-regulation of GABA(A) receptors in regions to which Purkinje cells project may partially compensate for their decreased activity in the mutant mice. The somata of cerebellar Purkinje cells of Scn8a ( medJ ) and Scn8a ( medJo ) mice, as revealed by PEP-19 immunoreaction, are slightly smaller than normal, and their axons, especially in Scn8a ( medJo ) mice, sometimes show enlargements similar to those in other types of mutant mice. Density of GABA-like immunoreactivity is decreased in Purkinje somata and regions of termination in deep cerebellar and vestibular nuclei of Scn8a ( medJ ) mice, but measured GABA concentration is not significantly reduced in microdissected samples of these regions. The concentrations of taurine and glutamine are significantly increased in cerebellar-related regions of Scn8a ( medJ ) mice, possibly suggesting up-regulation of glial amino acid metabolism.
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Gargus JJ. Genetic calcium signaling abnormalities in the central nervous system: seizures, migraine, and autism. Ann N Y Acad Sci 2009; 1151:133-56. [PMID: 19154521 DOI: 10.1111/j.1749-6632.2008.03572.x] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The calcium ion is one of the most versatile, ancient, and universal of biological signaling molecules, known to regulate physiological systems at every level from membrane potential and ion transporters to kinases and transcription factors. Disruptions of intracellular calcium homeostasis underlie a host of emerging diseases, the calciumopathies. Cytosolic calcium signals originate either as extracellular calcium enters through plasma membrane ion channels or from the release of an intracellular store in the endoplasmic reticulum (ER) via inositol triphosphate receptor and ryanodine receptor channels. Therefore, to a large extent, calciumopathies represent a subset of the channelopathies, but include regulatory pathways and the mitochondria, the major intracellular calcium repository that dynamically participates with the ER stores in calcium signaling, thereby integrating cellular energy metabolism into these pathways, a process of emerging importance in the analysis of the neurodegenerative and neuropsychiatric diseases. Many of the calciumopathies are common complex polygenic diseases, but leads to their understanding come most prominently from rare monogenic channelopathy paradigms. Monogenic forms of common neuronal disease phenotypes-such as seizures, ataxia, and migraine-produce a constitutionally hyperexcitable tissue that is susceptible to periodic decompensations. The gene families and genetic lesions underlying familial hemiplegic migraine, FHM1/CACNA1A, FHM2/ATP1A2, and FHM3/SCN1A, and monogenic mitochondrial migraine syndromes, provide a robust platform from which genes, such as CACNA1C, which encodes the calcium channel mutated in Timothy syndrome, can be evaluated for their role in autism and bipolar disease.
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Affiliation(s)
- J Jay Gargus
- Department of Physiology & Biophysics, Section of Human Genetics, School of Medicine, University of California-Irvine, Irvine, CA 92697, USA.
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Löscher W, Klotz U, Zimprich F, Schmidt D. The clinical impact of pharmacogenetics on the treatment of epilepsy. Epilepsia 2009; 50:1-23. [DOI: 10.1111/j.1528-1167.2008.01716.x] [Citation(s) in RCA: 186] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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