Abstract 20459: Epigenetic Activation of Phosphodiesterase Subtypes Lead to Compromised Beta-Adrenergic Signaling in Induced Pluripotent Stem Cell-Derived Cardiomyocytes From Dilated Cardiomyopathy Patients
Introduction: Familial dilated cardiomyopathy (DCM) has been modeled by human induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs). However, the mechanisms of compromised signaling transduction and contractile function in DCM iPSC-CMs are still not well understood.
Methods and Results: Beating iPSC-CMs were generated from healthy individuals and DCM patients. RNA-seq and real-time PCR showed strict regulation of the main beta-adrenergic signaling proteins in iPSC-CMs during maturation. Confocal imaging of spontaneous calcium activity and hydrogel-based traction force microscopy (TFM) technology demonstrated beta-adrenergic stimulation induced both inotropic and chronotropic regulation in the contractility of iPSC-CMs. Following extended in vitro maturation of iPSC-CMs, we observed a transition in the beta-adrenergic receptor (beta-AR) subtype dependence from beta-2 AR dominance at early stage (day 30) to beta-1/2 AR co-existence at late stage (day 60). Comparison of the beta-adrenergic responsiveness between iPSC-CMs from DCM patients and their familial controls showed compromised beta-adrenergic signaling in DCM cells. Microarray data and expression profiling indicated up-regulated phosphodiesterases (PDE) 2A, 3A and 5A in DCM iPSC-CMs, which impaired cAMP generation and blunted the beta-adrenergic response. By blocking PDE2A, 3A or 5A, beta-adrenergic signaling reactivity and contractile function in DCM iPSC-CMs were both greatly improved. To further elucidate underlying mechanism of PDE regulation, we conducted chromatin immunoprecipitation (CHIP) assays, which showed significant up-regulation of activation histone marker and down-regulation of repressive histone marker in the PDE promoters during maturation process of DCM iPSC-CMs, which closely recapitulated the epigenetic modulation in the ventricle tissues harvested from DCM patients.
Conclusions: Patient-specific DCM iPSC-CMs recapitulated impaired beta-adrenergic responsiveness and contractility in diseased heart. Studies on iPSC-CM model revealed a novel epigenetic mechanism that underlies PDE subtype specific regulation and signaling deficiency in DCM pathogenesis, which may serve as a new therapeutic target in the future.
Author Disclosures: H. Wu: None. J. Lee: None. M. Gu: None. F. Lan: None. J. Churko: None. V. Sanchez-Freire: None. E. Matsa: None. A. Ebert: None. K. Sallam: None. J. Gold: None. J. Wu: None.
This research has received full or partial funding support from the American Heart Association.
- © 2014 by American Heart Association, Inc.