CIC   05421
CENTRO DE INVESTIGACIONES CARDIOVASCULARES "DR. HORACIO EUGENIO CINGOLANI"
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
The Signaling Pathway for Aldosterone-induced Mitochondrial Production of Superoxide Anion in the Myocardium
Autor/es:
IRENE L ENNIS; CLAUDIA CALDIZ; MARIA C VILLA-ABRILLE; PATRICIO E MORGAN; GLADYS E CHIAPPE DE CINGOLANI; HORACIO E CINGOLANI
Lugar:
Los Angeles
Reunión:
Congreso; Scientific Sessions 2012; 2012
Institución organizadora:
American heart Association
Resumen:
Mineralocorticoid
receptor (MR) antagonists decrease morbidity and mortality in heart failure
patients for whom oxidative stress is common; however, the underlying mechanism
of MR-antagonist protection is unclear. Because aldosterone stimulates reactive
oxygen species production, we explored in rat myocardium the effect of
aldosterone on O2- production and the intracellular pathway involved.
Aldosterone dose-dependently stimulated O2- production. At 10 nmol/L,
aldosterone increased O2- to 165±8.8 % of control, an effect prevented by the
MR antagonists, eplerenone and spironolactone (107±7.8 and 103±5.3 %,
respectively), and by inhibition of EGF receptor (EGFR) with AG1478 (105±8.0%),
implicating EGFR transactivation in this pathway. Similar results were obtained
silencing MR expression by direct intramyocardial injection of a lentivirus
coding for a siRNA against the MR. The aldosterone effect was mimicked by the
mKATP channel opener diazoxide but blocked by preventing its opening with 5-HD
and glibenclamide, implicating the mitochondria as the O2- source. Inhibiting
the respiratory chain with rotenone also cancelled aldosterone-induced O2-
production. In addition, the aldosterone effect depended on NADPH oxidase and
phosphoinositide 3-kinase activation, as apocynin and wortmannin respectively
inhibited it. EGF (0.1µg/mL) similarly increased O2-, although in this case MR
antagonists had no effect, suggesting that EGFR transactivation occurred
downstream from MR. The results allow us to propose that a decrease in
oxidative stress may be one of the mechanisms contributing to the beneficial
effects of MR antagonists in heart failure.