Genomic upregulation of cardiac Cav1.2α and NCX1 by estrogen in women.
Biol Sex Differ
; 8(1): 26, 2017 08 14.
Article
em En
| MEDLINE
| ID: mdl-28807015
ABSTRACT
BACKGROUND:
Women have a higher risk of lethal arrhythmias than men in long QT syndrome type 2 (LQTS2), but the mechanisms remain uncertain due to the limited availability of healthy control human tissue. We have previously reported that in female rabbits, estrogen increases arrhythmia risk in drug-induced LQTS2 by upregulating L-type Ca2+ (ICa,L) and sodium-calcium exchange (INCX) currents at the base of the epicardium by a genomic mechanism. This study investigates if the effects of estrogen on rabbit ICa,L and INCX apply to human hearts.METHODS:
Postmortem human left ventricular tissue samples were probed with selective antibodies for regional heterogeneities of ion channel protein expression and compared to rabbit myocardium. Functionally, ICa,L and INCX were measured from female and male cardiomyocytes derived from human induced pluripotent stem cells (iPS-CMs) with the voltage-clamp technique from control and estrogen-treated iPS-CMs.RESULTS:
In women (n = 12), Cav1.2α (primary subunit of the L-type calcium channel protein 1) and NCX1 (sodium-calcium exchange protein) levels were higher at the base than apex of the epicardium (40 ± 14 and 81 ± 30%, respectively, P < 0.05), but not in men (n = 6) or postmenopausal women (n = 6). Similarly, in cardiomyocytes derived from female human iPS-CMs, estrogen (1 nM, 1-2 days) increased ICa,L (31%, P < 0.05) and INCX (7.5-fold, - 90 mV, P < 0.01) and their mRNA levels (P < 0.05). Moreover, in male human iPS-CMs, estrogen failed to alter ICa,L and INCX.CONCLUSIONS:
The results show that estrogen upregulates cardiac ICa,L and INCX in women through genomic mechanisms that account for sex differences in Ca2+ handling and spatial heterogeneities of repolarization due to base-apex heterogeneities of Cav1.2α and NCX1. By analogy with rabbit studies, these effects account for human sex-difference in arrhythmia risk.Palavras-chave
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Regulação para Cima
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Caracteres Sexuais
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Trocador de Sódio e Cálcio
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Canais de Cálcio Tipo L
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Miócitos Cardíacos
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Estrogênios
Limite:
Adolescent
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Adult
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Aged
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Animals
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Female
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Humans
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Male
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Middle aged
Idioma:
En
Revista:
Biol Sex Differ
Ano de publicação:
2017
Tipo de documento:
Article
País de afiliação:
Estados Unidos