Open AccessEmpagliflozin reduces Ca /calmodulin‐dependent kinase II activity in isolated ventricular cardiomyocytes
Author(s) -
Mustroph Julian,
Wagemann Olivia,
Lücht Charlotte M.,
Trum Maximilian,
Hammer Karin P.,
Sag Can Martin,
Lebek Simon,
Tarnowski Daniel,
Reinders Jörg,
Perbellini Filippo,
Terracciano Cesare,
Schmid Christof,
Schopka Simon,
Hilker Michael,
Zausig York,
Pabel Steffen,
Sossalla Samuel T.,
Schweda Frank,
Maier Lars S.,
Wagner Stefan
Publication year - 2018
Publication title -
esc heart failure
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.787
H-Index - 25
ISSN - 2055-5822
DOI - 10.1002/ehf2.12336
Subject(s) - empagliflozin , myocyte , medicine , endocrinology , ryanodine receptor , heart failure , calmodulin , chemistry , calcium , diabetes mellitus , type 2 diabetes mellitus
Aims The EMPA‐REG OUTCOME study showed reduced mortality and hospitalization due to heart failure (HF) in diabetic patients treated with empagliflozin. Overexpression and Ca 2+ ‐dependent activation of Ca 2+ /calmodulin‐dependent kinase II (CaMKII) are hallmarks of HF, leading to contractile dysfunction and arrhythmias. We tested whether empagliflozin reduces CaMKII‐ activity and improves Ca 2+ ‐handling in human and murine ventricular myocytes. Methods and results Myocytes from wild‐type mice, mice with transverse aortic constriction (TAC) as a model of HF, and human failing ventricular myocytes were exposed to empagliflozin (1 μmol/L) or vehicle. CaMKII activity was assessed by CaMKII–histone deacetylase pulldown assay. Ca 2+ spark frequency (CaSpF) as a measure of sarcoplasmic reticulum (SR) Ca 2+ leak was investigated by confocal microscopy. [Na + ] i was measured using Na + /Ca 2+ ‐exchanger (NCX) currents (whole‐cell patch clamp). Compared with vehicle, 24 h empagliflozin exposure of murine myocytes reduced CaMKII activity (1.6 ± 0.7 vs. 4.2 ± 0.9, P < 0.05, n = 10 mice), and also CaMKII‐dependent ryanodine receptor phosphorylation (0.8 ± 0.1 vs. 1.0 ± 0.1, P < 0.05, n = 11 mice), with similar results upon TAC. In murine myocytes, empagliflozin reduced CaSpF (TAC: 1.7 ± 0.3 vs. 2.5 ± 0.4 1/100 μm −1 s −1 , P < 0.05, n = 4 mice) but increased SR Ca 2+ load and Ca 2+ transient amplitude. Importantly, empagliflozin also significantly reduced CaSpF in human failing ventricular myocytes (1 ± 0.2 vs. 3.3 ± 0.9, P < 0.05, n = 4 patients), while Ca 2+ transient amplitude was increased (F/F 0 : 0.53 ± 0.05 vs. 0.36 ± 0.02, P < 0.05, n = 3 patients). In contrast, 30 min exposure with empagliflozin did not affect CaMKII activity nor Ca 2+ ‐handling but significantly reduced [Na + ] i . Conclusions We show for the first time that empagliflozin reduces CaMKII activity and CaMKII‐dependent SR Ca 2+ leak. Reduced Ca 2+ leak and improved Ca 2+ transients may contribute to the beneficial effects of empagliflozin in HF.