Expression of immediate early genes, GATA-4, and Nkx-2.5 in adrenergic-induced cardiac hypertrophy and during regression in adult mice

Authors

  • Nacéra Saadane,

    1. Lady Davis Institute for Medical Research, Sir Mortimer B. Davis–Jewish General Hospital, 3755 chemin Côte Sainte Catherine, Montréal, Québec, Canada, H3T 1E2
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  • Lesley Alpert,

    1. Department of Pathology, Sir Mortimer B. Davis–Jewish General Hospital, 3755 chemin Côte Sainte Catherine, Montréal, Québec, Canada, H3T 1E2
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  • Lorraine E Chalifour

    Corresponding author
    1. Lady Davis Institute for Medical Research, Sir Mortimer B. Davis–Jewish General Hospital, 3755 chemin Côte Sainte Catherine, Montréal, Québec, Canada, H3T 1E2
    2. Division of Experimental Medicine, Department of Medicine, McGill University, Montréal, Québec, Canada, H3A 1A3
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Lady Davis Institute for Medical Research, Sir Mortimer B. Davis — Jewish General Hospital, 3755 Chemin Côte Sainte Catherine, Montréal, Québec, Canada, H3T 1E2. E-mail: CZLC@MusicA.McGill.CA

Abstract

  • Adrenoreceptor agonists induce a hypertrophic phenotype in vitro and in vivo. To investigate the molecular remodeling in chronic cardiac hypertrophy we infused adult male mice with vehicle, isoproterenol, phenylephrine or both agonists for 3, 7 or 14 days.

  • All drugs increased cardiac mass. After minipump removal cardiac mass regressed to control levels within 7 days after PE and ISO treatment whereas ISO+PE treated hearts were incompletely regressed.

  • ANF and β-MHC, but not α-MHC, expression were increased by agonists at all time points. GATA-4, Nkx-2.5, Egr-1, c-jun and c-fos expression were increased after 3, 7 and 14 days of treatment. Expression was greatest after ISO+PE>>ISO>PE>vehicle infusion suggesting a synergistic effect of adrenoreceptor stimulation and indicating a greater effect of β- than α-adrenergic action in vivo.

  • After PE or ISO drug withdrawal the HW/BW was normal and Egr-1, c-jun, c-fos and GATA-4, but not Nkx2.5, expression dropped to control levels. HW/BW regression was incomplete after ISO+PE and elevated levels of Egr-1, c-jun and Nkx2.5 expression remained.

  • A hydralazine-mediated reduction in blood pressure had no effect on the agonist-induced cardiac hypertrophy or gene expression.

  • In conclusion, we found that continued agonist stimulation, and not blood pressure, is responsible for the maintained increase in gene expression. Further, we found the decrease in gene expression in the regression after drug withdrawal was gene specific.

British Journal of Pharmacology (1999) 127, 1165–1176; doi:10.1038/sj.bjp.0702676

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