Phospholamban ablation rescues the enhanced propensity to arrhythmias of mice with CaMKII-constitutive phosphorylation of RyR2 at site S2814.

Autor: Mazzocchi G; Centro de Investigaciones Cardiovasculares, CCT-La Plata-CONICET, Facultad de Cs Médicas, UNLP, La Plata, Argentina., Sommese L; Centro de Investigaciones Cardiovasculares, CCT-La Plata-CONICET, Facultad de Cs Médicas, UNLP, La Plata, Argentina., Palomeque J; Centro de Investigaciones Cardiovasculares, CCT-La Plata-CONICET, Facultad de Cs Médicas, UNLP, La Plata, Argentina., Felice JI; Centro de Investigaciones Cardiovasculares, CCT-La Plata-CONICET, Facultad de Cs Médicas, UNLP, La Plata, Argentina., Di Carlo MN; Centro de Investigaciones Cardiovasculares, CCT-La Plata-CONICET, Facultad de Cs Médicas, UNLP, La Plata, Argentina., Fainstein D; Centro de Investigaciones Cardiovasculares, CCT-La Plata-CONICET, Facultad de Cs Médicas, UNLP, La Plata, Argentina., Gonzalez P; Cátedra de Patología, Facultad de Cs Médicas, UNLP, La Plata, Argentina., Contreras P; Departamento de Fisiología, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay., Skapura D; Departments of Molecular Physiology and Biophysics, Medicine (in Cardiology), and Pediatrics, Baylor College of Medicine, Cardiovascular Research Institute, Houston, TX, 77030, USA., McCauley MD; Departments of Molecular Physiology and Biophysics, Medicine (in Cardiology), and Pediatrics, Baylor College of Medicine, Cardiovascular Research Institute, Houston, TX, 77030, USA., Lascano EC; Departamento de Biología Comparada, Celular y Molecular, Universidad Favaloro, Ciudad Autónoma de Buenos Aires, Argentina., Negroni JA; Departamento de Biología Comparada, Celular y Molecular, Universidad Favaloro, Ciudad Autónoma de Buenos Aires, Argentina., Kranias EG; Department of Pharmacology, University of Cincinnati College of Medicine, Cincinnati, OH, 45267., Wehrens XH; Departments of Molecular Physiology and Biophysics, Medicine (in Cardiology), and Pediatrics, Baylor College of Medicine, Cardiovascular Research Institute, Houston, TX, 77030, USA., Valverde CA; Centro de Investigaciones Cardiovasculares, CCT-La Plata-CONICET, Facultad de Cs Médicas, UNLP, La Plata, Argentina., Mattiazzi A; Centro de Investigaciones Cardiovasculares, CCT-La Plata-CONICET, Facultad de Cs Médicas, UNLP, La Plata, Argentina.
Jazyk: angličtina
Zdroj: The Journal of physiology [J Physiol] 2016 Jun 01; Vol. 594 (11), pp. 3005-30. Date of Electronic Publication: 2016 Feb 02.
DOI: 10.1113/JP271622
Abstrakt: Key Points: Mice with Ca(2+) -calmodulin-dependent protein kinase (CaMKII) constitutive pseudo-phosphorylation of the ryanodine receptor RyR2 at Ser2814 (S2814D(+/+) mice) exhibit a higher open probability of RyR2, higher sarcoplasmic reticulum (SR) Ca(2+) leak in diastole and increased propensity to arrhythmias under stress conditions. We generated phospholamban (PLN)-deficient S2814D(+/+) knock-in mice by crossing two colonies, S2814D(+/+) and PLNKO mice, to test the hypothesis that PLN ablation can prevent the propensity to arrhythmias of S2814D(+/+) mice. PLN ablation partially rescues the altered intracellular Ca(2+) dynamics of S2814D(+/+) hearts and myocytes, but enhances SR Ca(2+) sparks and leak on confocal microscopy. PLN ablation diminishes ventricular arrhythmias promoted by CaMKII phosphorylation of S2814 on RyR2. PLN ablation aborts the arrhythmogenic SR Ca(2+) waves of S2814D(+/+) and transforms them into non-propagating events. A mathematical human myocyte model replicates these results and predicts the increase in SR Ca(2+) uptake required to prevent the arrhythmias induced by a CaMKII-dependent leaky RyR2.
Abstract: Mice with constitutive pseudo-phosphorylation at Ser2814-RyR2 (S2814D(+/+) ) have increased propensity to arrhythmias under β-adrenergic stress conditions. Although abnormal Ca(2+) release from the sarcoplasmic reticulum (SR) has been linked to arrhythmogenesis, the role played by SR Ca(2+) uptake remains controversial. We tested the hypothesis that an increase in SR Ca(2+) uptake is able to rescue the increased arrhythmia propensity of S2814D(+/+) mice. We generated phospholamban (PLN)-deficient/S2814D(+/+) knock-in mice by crossing two colonies, S2814D(+/+) and PLNKO mice (SD(+/+) /KO). SD(+/+) /KO myocytes exhibited both increased SR Ca(2+) uptake seen in PLN knock-out (PLNKO) myocytes and diminished SR Ca(2+) load (relative to PLNKO), a characteristic of S2814D(+/+) myocytes. Ventricular arrhythmias evoked by catecholaminergic challenge (caffeine/adrenaline) in S2814D(+/+) mice in vivo or programmed electric stimulation and high extracellular Ca(2+) in S2814D(+) /(-) hearts ex vivo were significantly diminished by PLN ablation. At the myocyte level, PLN ablation converted the arrhythmogenic Ca(2+) waves evoked by high extracellular Ca(2+) provocation in S2814D(+/+) mice into non-propagated Ca(2+) mini-waves on confocal microscopy. Myocyte Ca(2+) waves, typical of S2814D(+/+) mice, could be evoked in SD(+/+) /KO cells by partially inhibiting SERCA2a. A mathematical human myocyte model replicated these results and allowed for predicting the increase in SR Ca(2+) uptake required to prevent the arrhythmias induced by a Ca(2+) -calmodulin-dependent protein kinase (CaMKII)-dependent leaky RyR2. Our results demonstrate that increasing SR Ca(2+) uptake by PLN ablation can prevent the arrhythmic events triggered by SR Ca(2+) leak due to CaMKII-dependent phosphorylation of the RyR2-S2814 site and underscore the benefits of increasing SERCA2a activity on SR Ca(2+) -triggered arrhythmias.
(© 2015 The Authors. The Journal of Physiology © 2015 The Physiological Society.)
Databáze: MEDLINE
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