Phosphoinositide 3-kinase gamma-deficient mice are protected from isoproterenol-induced heart failure

Article

关键词: AKT/PROTEIN KINASE-B;    CARDIAC-HYPERTROPHY;    SIGNALING PATHWAYS;    TUMOR-SUPPRESSOR;    RECEPTOR;    ACTIVATION;    POLYMORPHISMS;    SUBTYPES;    GROWTH;    SIZE;   

DOI  :  10.1161/01.CIR.0000091403.62293.2B

来源: SCIE

【 摘 要 】

Background - We have recently shown that genetic inactivation of phosphoinositide 3-kinase gamma (PI3Kgamma), the isoform linked to G-protein-coupled receptors, results in increased cardiac contractility with no effect on basal cell size. Signaling via the G-protein-coupled beta-adrenergic receptors has been implicated in cardiac hypertrophy and heart failure, suggesting that PI3Kgamma might play a role in the pathogenesis of heart disease. Methods and Results - To determine the role for PI3Kgamma in hypertrophy induced by G-protein-coupled receptors and cardiomyopathy, we infused isoproterenol, a beta-adrenergic receptor agonist, into PI3Kgamma-deficient mice. Compared with controls, isoproterenol infusion in PI3Kgamma-deficient mice resulted in an attenuated cardiac hypertrophic response and markedly reduced interstitial fibrosis. Intriguingly, chronic beta-adrenergic receptor stimulation triggered impaired heart functions in wild-type mice, whereas PI3Kgamma-deficient mice retained their increased heart function and did not develop heart failure. The lack of PI3Kgamma attenuated the activation of Akt/protein kinase B and extracellular signal-regulated kinase 1/2 signaling pathways in cardiac myocytes in response to isoproterenol. beta(1)- and beta(2)-adrenergic receptor densities were decreased by similar amounts in PI3Kgamma-deficient and control mice, suggesting that PI3Kgamma isoform plays no role in the downregulation of beta-adrenergic receptors after chronic beta-adrenergic stimulation. Conclusions - Our data show that PI3Kgamma is critical for the induction of hypertrophy, fibrosis, and cardiac dysfunction function in response to beta-adrenergic receptor stimulation in vivo. Thus, PI3Kgamma may represent a novel therapeutic target for the treatment of decreased cardiac function in heart failure.

【 授权许可】

Free