Inhibition of elevated Ca2+/calmodulin-dependent protein kinase II improves contractility in human failing myocardium
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Inhibition of elevated Ca2+/calmodulin-dependent protein kinase II improves contractility in human failing myocardium. / Sossalla, Samuel; Fluschnik, Nina; Schotola, Hanna; Ort, Katharina R; Neef, Stefan; Schulte, Timo; Wittköpper, Katrin; Renner, André; Schmitto, Jan D; Gummert, Jan; El-Armouche, Ali; Hasenfuss, Gerd; Maier, Lars S.
in: CIRC RES, Jahrgang 107, Nr. 9, 29.10.2010, S. 1150-1161.Publikationen: SCORING: Beitrag in Fachzeitschrift/Zeitung › SCORING: Zeitschriftenaufsatz › Forschung › Begutachtung
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TY - JOUR
T1 - Inhibition of elevated Ca2+/calmodulin-dependent protein kinase II improves contractility in human failing myocardium
AU - Sossalla, Samuel
AU - Fluschnik, Nina
AU - Schotola, Hanna
AU - Ort, Katharina R
AU - Neef, Stefan
AU - Schulte, Timo
AU - Wittköpper, Katrin
AU - Renner, André
AU - Schmitto, Jan D
AU - Gummert, Jan
AU - El-Armouche, Ali
AU - Hasenfuss, Gerd
AU - Maier, Lars S
PY - 2010/10/29
Y1 - 2010/10/29
N2 - RATIONALE: Heart failure (HF) is known to be associated with increased Ca(2+)/calmodulin-dependent protein kinase (CaMK)II expression and activity. There is still controversial discussion about the functional role of CaMKII in HF. Moreover, CaMKII inhibition has never been investigated in human myocardium.OBJECTIVE: We sought to investigate detailed CaMKIIδ expression in end-stage failing human hearts (dilated and ischemic cardiomyopathy) and the functional effects of CaMKII inhibition on contractility.METHODS AND RESULTS: Expression analysis revealed that CaMKIIδ, both cytosolic δ(C) and nuclear δ(B) splice variants, were significantly increased in both right and left ventricles from patients with dilated or ischemic cardiomyopathy versus nonfailing. Experiments with isometrically twitching trabeculae revealed significantly improved force frequency relationships in the presence of CaMKII inhibitors (KN-93 and AIP). Increased postrest twitches after CaMKII inhibition indicated an improved sarcoplasmic reticulum (SR) Ca(2+) loading. This was confirmed in isolated myocytes by a reduced SR Ca(2+) spark frequency and hence SR Ca(2+) leak, resulting in increased SR Ca(2+) load when inhibiting CaMKII. Ryanodine receptor type 2 phosphorylation at Ser2815, which is known to be phosphorylated by CaMKII thereby contributing to SR Ca(2+) leak, was found to be markedly reduced in KN-93-treated trabeculae. Interestingly, CaMKII inhibition did not influence contractility in nonfailing sheep trabeculae.CONCLUSIONS: The present study shows for the first time that CaMKII inhibition acutely improves contractility in human HF where CaMKIIδ expression is increased. The mechanism proposed consists of a reduced SR Ca(2+) leak and consequently increased SR Ca(2+) load. Thus, CaMKII inhibition appears to be a possible therapeutic option for patients with HF and merits further investigation.
AB - RATIONALE: Heart failure (HF) is known to be associated with increased Ca(2+)/calmodulin-dependent protein kinase (CaMK)II expression and activity. There is still controversial discussion about the functional role of CaMKII in HF. Moreover, CaMKII inhibition has never been investigated in human myocardium.OBJECTIVE: We sought to investigate detailed CaMKIIδ expression in end-stage failing human hearts (dilated and ischemic cardiomyopathy) and the functional effects of CaMKII inhibition on contractility.METHODS AND RESULTS: Expression analysis revealed that CaMKIIδ, both cytosolic δ(C) and nuclear δ(B) splice variants, were significantly increased in both right and left ventricles from patients with dilated or ischemic cardiomyopathy versus nonfailing. Experiments with isometrically twitching trabeculae revealed significantly improved force frequency relationships in the presence of CaMKII inhibitors (KN-93 and AIP). Increased postrest twitches after CaMKII inhibition indicated an improved sarcoplasmic reticulum (SR) Ca(2+) loading. This was confirmed in isolated myocytes by a reduced SR Ca(2+) spark frequency and hence SR Ca(2+) leak, resulting in increased SR Ca(2+) load when inhibiting CaMKII. Ryanodine receptor type 2 phosphorylation at Ser2815, which is known to be phosphorylated by CaMKII thereby contributing to SR Ca(2+) leak, was found to be markedly reduced in KN-93-treated trabeculae. Interestingly, CaMKII inhibition did not influence contractility in nonfailing sheep trabeculae.CONCLUSIONS: The present study shows for the first time that CaMKII inhibition acutely improves contractility in human HF where CaMKIIδ expression is increased. The mechanism proposed consists of a reduced SR Ca(2+) leak and consequently increased SR Ca(2+) load. Thus, CaMKII inhibition appears to be a possible therapeutic option for patients with HF and merits further investigation.
KW - Animals
KW - Calcium-Calmodulin-Dependent Protein Kinase Type 2/antagonists & inhibitors
KW - Cells, Cultured
KW - Heart Failure/drug therapy
KW - Humans
KW - Myocardial Contraction/drug effects
KW - Myocardium/enzymology
KW - Protein Kinase Inhibitors/pharmacology
KW - Sheep
U2 - 10.1161/CIRCRESAHA.110.220418
DO - 10.1161/CIRCRESAHA.110.220418
M3 - SCORING: Journal article
C2 - 20814023
VL - 107
SP - 1150
EP - 1161
JO - CIRC RES
JF - CIRC RES
SN - 0009-7330
IS - 9
ER -