Cavβ2 transcription start site variants modulate calcium handling in newborn rat cardiomyocytes

Cristian Moreno, Tamara Hermosilla, Danna Morales, Matías Encina, Leandro Torres-Díaz, Pablo Díaz, Daniela Sarmiento, Felipe Simon, Diego Varela

Resultado de la investigación: Contribución a una revistaArtículorevisión exhaustiva

4 Citas (Scopus)

Resumen

In the heart, the main pathway for calcium influx is mediated by L-type calcium channels, a multi-subunit complex composed of the pore-forming subunit CaV1.2 and the auxiliary subunits CaVα2δ1 and CaVβ2. To date, five distinct CaVβ2 transcriptional start site (TSS) variants (CaVβ2a-e) varying only in the composition and length of the N-terminal domain have been described, each of them granting distinct biophysical properties to the L-type current. However, the physiological role of these variants in Ca2+ handling in the native tissue has not been explored. Our results show that four of these variants are present in neonatal rat cardiomyocytes. The contribution of those CaVβ2 TSS variants on endogenous L-type current and Ca2+ handling was explored by adenoviral-mediated overexpression of each CaVβ2 variant in cultured newborn rat cardiomyocytes. As expected, all CaVβ2 TSS variants increased L-type current density and produced distinctive changes on L-type calcium channel (LTCC) current activation and inactivation kinetics. The characteristics of the induced calcium transients were dependent on the TSS variant overexpressed. Moreover, the amplitude of the calcium transients varied depending on the subunit involved, being higher in cardiomyocytes transduced with CaVβ2a and smaller in CaVβ2d. Interestingly, the contribution of Ca2+ influx and Ca2+ release on total calcium transients, as well as the sarcoplasmic calcium content, was found to be TSS-variant-dependent. Remarkably, determination of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) messenger RNA (mRNA) abundance and cell size change indicates that CaVβ2 TSS variants modulate the cardiomyocyte hypertrophic state. In summary, we demonstrate that expression of individual CaVβ2 TSS variants regulates calcium handling in cardiomyocytes and, consequently, has significant repercussion in the development of hypertrophy.

Idioma originalInglés
Páginas (desde-hasta)2473-2484
Número de páginas12
PublicaciónPflugers Archiv European Journal of Physiology
Volumen467
N.º12
DOI
EstadoPublicada - 1 dic 2015

Áreas temáticas de ASJC Scopus

  • Fisiología
  • Bioquímica clínica
  • Fisiología (médica)

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