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

Abstract

Rationale: Autoantibodies directed against the beta1-adrenoceptor (beta1-AABs) have been proposed to drive the pathogenesis of idiopathic dilated cardiomyoparthy (DCM), Chagas' 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, Chagas' 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:

The First Aptamer-Apheresis Column Specifically for Clearing Blood of β1-Receptor Autoantibodies

“…11 Our previously selected aptamer using the Monolex technology 12 bound β1-AABs isolated from patients with DCM, Chagas' cardiomyopathy, or peripartum cardiomyopathy and neutralized their pathogenic functions, which we demonstrated in vitro by reducing β1-AAB-induced chronotropy and apoptosis. 1 However, as recently discussed, 13 the relationship between the selected aptamer and β1-AABs must be consolidated in vivo using animal models.…”

A standardised FACS assay based on native, receptor transfected cells for the clinical diagnosis and monitoring of β1-adrenergic receptor autoantibodies in human heart disease

“…Novel therapy-modalities specifically directed against cardio-noxious β 1 AR-autoantibodies comprise extracorporeal IgG-absorption [14][15][16] and neutralisation/clearance of β 1 AR-autoantibodies by systemic administration of synthetic epitope mimics [17][18][19][20]. DCM patients with reduced cardiac function are considered to benefit from therapies selective for β 1 AR-autoantibodies only when they are positive for β 1 AR-autoantibodies [14,15].…”

Aptamer Therapy for Heart Failure?

“…To be useful in the clinical setting, such a treatment must be conveniently administered and be relatively free of adverse events. In the current issue of Circulation Research, Haberland et al 19 demonstrate that a singlestrand DNA aptamer could be such a therapeutic compound.…”

“…In the current article, Haberland et al 19 use MonoLEX technology, 35 a variant of SELEX, to generate aptamers that neutralize and inactivate ␤ 1 -AR AAbs. Interestingly, the 21 nucleotide DNA sequence investigated, aptamer 110, markedly attenuated ␤ 1 -AR AAb-mediated increases in heart rate and apoptosis in cultured cardiac myocytes.…”

“…The details of chronic treatment, presumably by intravenous or subcutaneous routes of administration, would need to be defined, efficacy would need to be demonstrated, and an acceptable adverse event profile would need to be documented. However, Haberland et al, 19 should be congratulated for creating this drug developmental opportunity. …”