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A Novel SCN9A Mutation Responsible for Primary Erythromelalgia and Is Resistant to the Treatment of Sodium Channel Blockers

Primary erythromelalgia (PE) is an autosomal dominant neurological disorder characterized by severe burning pain and erythema in the extremities upon heat stimuli or exercise. Mutations in human SCN9A gene, encoding the α–subunit of the voltage-gated sodium channel, Na(v)1.7, were found to be respon...

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Autores principales: Wu, Min-Tzu, Huang, Po-Yuan, Yen, Chen-Tung, Chen, Chih-Cheng, Lee, Ming-Jen
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2013
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3561374/
https://www.ncbi.nlm.nih.gov/pubmed/23383113
http://dx.doi.org/10.1371/journal.pone.0055212
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author Wu, Min-Tzu
Huang, Po-Yuan
Yen, Chen-Tung
Chen, Chih-Cheng
Lee, Ming-Jen
author_facet Wu, Min-Tzu
Huang, Po-Yuan
Yen, Chen-Tung
Chen, Chih-Cheng
Lee, Ming-Jen
author_sort Wu, Min-Tzu
collection PubMed
description Primary erythromelalgia (PE) is an autosomal dominant neurological disorder characterized by severe burning pain and erythema in the extremities upon heat stimuli or exercise. Mutations in human SCN9A gene, encoding the α–subunit of the voltage-gated sodium channel, Na(v)1.7, were found to be responsible for PE. Three missense mutations of SCN9A gene have recently been identified in Taiwanese patients including a familial (I136V) and two sporadic mutations (I848T, V1316A). V1316A is a novel mutation and has not been characterized yet. Topologically, I136V is located in DI/S1 segment and both I848T and V1316A are located in S4-S5 linker region of DII and DIII domains, respectively. To characterize the elelctrophysiological manifestations, the channel conductance with whole-cell patch clamp was recorded on the over-expressed Chinese hamster overy cells. As compared with wild type, the mutant channels showed a significant hyperpolarizing shift in voltage dependent activation and a depolarizing shift in steady-state fast inactivation. The recovery time from channel inactivation is faster in the mutant than in the wild type channels. Since warmth can trigger and exacerbate symptoms, we then examine the influence of tempearture on the sodium channel conduction. At 35°C, I136V and V1316A mutant channels exhibit a further hyperpolarizing shift at activation as compared with wild type channel, even though wild type channel also produced a significant hyperpolarizing shift compared to that of 25°C. High temperature caused a significant depolarizing shift in steady-state fast inactivation in all three mutant channels. These findings may confer to the hyperexcitability of sensory neurons, especially at high temperature. In order to identifying an effective treatment, we tested the IC(50) values of selective sodium channel blockers, lidocaine and mexiletine. The IC(50) for mexiletine is lower for I848T mutant channel as compared to that of the wild type and other two mutants which is comparable to the clinical observations.
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spelling pubmed-35613742013-02-04 A Novel SCN9A Mutation Responsible for Primary Erythromelalgia and Is Resistant to the Treatment of Sodium Channel Blockers Wu, Min-Tzu Huang, Po-Yuan Yen, Chen-Tung Chen, Chih-Cheng Lee, Ming-Jen PLoS One Research Article Primary erythromelalgia (PE) is an autosomal dominant neurological disorder characterized by severe burning pain and erythema in the extremities upon heat stimuli or exercise. Mutations in human SCN9A gene, encoding the α–subunit of the voltage-gated sodium channel, Na(v)1.7, were found to be responsible for PE. Three missense mutations of SCN9A gene have recently been identified in Taiwanese patients including a familial (I136V) and two sporadic mutations (I848T, V1316A). V1316A is a novel mutation and has not been characterized yet. Topologically, I136V is located in DI/S1 segment and both I848T and V1316A are located in S4-S5 linker region of DII and DIII domains, respectively. To characterize the elelctrophysiological manifestations, the channel conductance with whole-cell patch clamp was recorded on the over-expressed Chinese hamster overy cells. As compared with wild type, the mutant channels showed a significant hyperpolarizing shift in voltage dependent activation and a depolarizing shift in steady-state fast inactivation. The recovery time from channel inactivation is faster in the mutant than in the wild type channels. Since warmth can trigger and exacerbate symptoms, we then examine the influence of tempearture on the sodium channel conduction. At 35°C, I136V and V1316A mutant channels exhibit a further hyperpolarizing shift at activation as compared with wild type channel, even though wild type channel also produced a significant hyperpolarizing shift compared to that of 25°C. High temperature caused a significant depolarizing shift in steady-state fast inactivation in all three mutant channels. These findings may confer to the hyperexcitability of sensory neurons, especially at high temperature. In order to identifying an effective treatment, we tested the IC(50) values of selective sodium channel blockers, lidocaine and mexiletine. The IC(50) for mexiletine is lower for I848T mutant channel as compared to that of the wild type and other two mutants which is comparable to the clinical observations. Public Library of Science 2013-01-31 /pmc/articles/PMC3561374/ /pubmed/23383113 http://dx.doi.org/10.1371/journal.pone.0055212 Text en © 2013 Wu et al http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.
spellingShingle Research Article
Wu, Min-Tzu
Huang, Po-Yuan
Yen, Chen-Tung
Chen, Chih-Cheng
Lee, Ming-Jen
A Novel SCN9A Mutation Responsible for Primary Erythromelalgia and Is Resistant to the Treatment of Sodium Channel Blockers
title A Novel SCN9A Mutation Responsible for Primary Erythromelalgia and Is Resistant to the Treatment of Sodium Channel Blockers
title_full A Novel SCN9A Mutation Responsible for Primary Erythromelalgia and Is Resistant to the Treatment of Sodium Channel Blockers
title_fullStr A Novel SCN9A Mutation Responsible for Primary Erythromelalgia and Is Resistant to the Treatment of Sodium Channel Blockers
title_full_unstemmed A Novel SCN9A Mutation Responsible for Primary Erythromelalgia and Is Resistant to the Treatment of Sodium Channel Blockers
title_short A Novel SCN9A Mutation Responsible for Primary Erythromelalgia and Is Resistant to the Treatment of Sodium Channel Blockers
title_sort novel scn9a mutation responsible for primary erythromelalgia and is resistant to the treatment of sodium channel blockers
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3561374/
https://www.ncbi.nlm.nih.gov/pubmed/23383113
http://dx.doi.org/10.1371/journal.pone.0055212
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