An Adenosine A₁ Agonist 2-Chloro-N6 Cyclopentyladenosine Inhibits the Angiotensin II-Induced Cardiomyocyte Hypertrophy through the Calcineurin Pathway

• DOI: 10.1159/000364995
• Publication Date: 2014-10-02T12:10:37Z
• Authors: Xingliang Zhang; Juan Xia; Dandan Qian; Yang Wang; Yongwen Lin; Xiulan Huang; Jianxin Tan
• Keywords: 0301 basic medicine; Myosin Heavy Chains; Angiotensin II; Calcineurin; In Vitro Techniques; Adenosine A1 Receptor Agonists; Rats; 3. Good health; 03 medical and health sciences; Natriuretic Peptide, Brain; Cyclosporine; Animals; Myocytes, Cardiac; RNA, Messenger; Enzyme Inhibitors; Signal Transduction

<b><i>Objectives:</i></b> The aim of this investigation was to study the underlying mechanism of an adenosine A₁ receptor agonist 2-chloro-N6 cyclopentyladenosine (CCPA) inhibiting cardiomyocyte hypertrophy induced by angiotensin II (AngII). <b><i>Methods:</i></b> Neonatal rat cardiomyocytes were treated with AngII to generate a cardiomyocyte hypertrophy model. Cardiomyocyte cultures were randomized into 5 groups: control; AngII; AngII + cyclosporin A (CsA); AngII + CCPA, and AngII + CCPA + DPCPX. Cardiomyocyte viability was measured by MTT assay. Protein synthesis was assessed by the application of ³H leucine (³H-Leu) incorporation into protein. The mRNA expressions of atrial natriuretic peptide (ANP), B-type natriuretic peptide (BNP), β-myosin heavy chain (β-MHC) and calcineurin Aβ (CnAβ) were measured by real-time quantitative PCR. The protein level of CnAβ was dissected by Western blotting. <b><i>Results:</i></b> AngII administration at lower concentrations increased the cardiomyocytes viabilities gradually. Surface area, mRNA expressions of ANP, BNP and β-MHC, and ³H-Leu incorporation of AngII-induced cardiomyocytes were increased in a dose-dependent manner. As a calcineurin-specific inhibitor, CsA inhibited ³H-Leu incorporation, surface area, mRNA expressions of ANP, BNP, β-MHC, CnAβ and protein expression of CnAβ of AngII-induced cardiomyocytes. CCPA also suppressed the mRNA and protein expressions of CnAβ and exerted antihypertrophic effects to a greater degree than CsA. The inhibition of CCPA on cardiomyocyte hypertrophy was counteracted by the A₁ receptor antagonist DPCPX. <b><i>Conclusion:</i></b> The A₁ receptor agonist CCPA could significantly inhibit AngII-induced cardiomyocyte hypertrophy via the calcineurin signaling pathway.