Aptamer Neutralization of Beta1-Adrenoceptor Autoantibodies Isolated From Patients With Cardiomyopathies

• Published in: Circulation research 2011-10, Vol.109 (9), p.986-992
• Main Authors: Haberland, Annekathrin, Wallukat, Gerd, Dahmen, Claudia, Kage, Andreas, Schimke, Ingolf
• Format: Article
• Language: English
• Subjects: Adrenergic beta-1 Receptor Agonists - pharmacology; Adrenergic beta-1 Receptor Antagonists - pharmacology; Animals; Antibody Specificity; Apoptosis - drug effects; Apoptosis - physiology; Aptamers, Nucleotide - pharmacology; Autoantibodies - drug effects; Autoantibodies - immunology; Autoantibodies - metabolism; Bisoprolol - pharmacology; Cardiomyopathy, Dilated - immunology; Cells, Cultured; Chagas Cardiomyopathy - immunology; Dose-Response Relationship, Drug; Humans; In Vitro Techniques; Isoproterenol - pharmacology; Myocytes, Cardiac - drug effects; Myocytes, Cardiac - immunology; Myocytes, Cardiac - metabolism; Rats; Receptors, Adrenergic, beta-1 - immunology; Receptors, Adrenergic, beta-1 - metabolism
• ISSN: 0009-7330; 1524-4571
• DOI: 10.1161/CIRCRESAHA.111.253849

RATIONALE:Autoantibodies directed against the beta1-adrenoceptor (beta1-AABs) have been proposed to drive the pathogenesis of idiopathic dilated cardiomyoparthy (DCM), Chagasʼ cardiomyopathy, and peripartum cardiomyopathy. For disease treatment, aptamers that bind and neutralize beta1-AABs could be significant. OBJECTIVE:We determined whether oligonucleotide-aptamers, selected to target human beta1-AABs directed against the second extracellular loop of the beta1-AAB, can neutralize these AABs and modulate their function in vitro. METHODS AND RESULTS:Using Monolex technology, we identified an ssDNA aptamer that targets human beta1-AABs. The neutralization potential of this aptamer against beta1-AABs isolated from patients with DCM, Chagasʼ cardiomyopathy, and peripartum cardiomyopathy was analyzed using cultured neonatal rat cardiomyocytes by monitoring beta1-AAB induced cell toxicity and chronotropic cell responses. Aptamer addition reduced beta1-AAB induced cell toxicity and neutralized chonotropic beta1-AAB function in a dose-dependent manner. In the presence of aptamer neutralized beta1-AABs, cells remained fully responsive to agonists and antagonists, such as isoprenaline and bisoprolol. Both aptamer pretreated with a complementary (antisense) aptamer and a control scrambled-sequence aptamer were ineffective at beta1-AAB neutralization. Beta1-AABs directed against the first extracellular loop of the beta1-receptor and AABs directed against other G-protein coupled receptors were not affected by the selected aptamer. CONCLUSIONS:A specific aptamer that can neutralize cardiomyopathy associated human beta1-AABs in vitro has been identified and characterized, providing a framework for future in vivo testing of this treatment option in animal experiments.