TY  - JOUR
A1  - Budde, Heidi
A1  - Hassoun, Roua
A1  - Tangos, Melina
A1  - Zhazykbayeva, Saltanat
A1  - Herwig, Melissa
A1  - Varatnitskaya, Marharyta
A1  - Sieme, Marcel
A1  - Delalat, Simin
A1  - Sultana, Innas
A1  - Kolijn, Detmar
A1  - Gömöri, Kamilla
A1  - Jarkas, Muhammad
A1  - Lódi, Mária
A1  - Jaquet, Kornelia
A1  - Kovács, Árpád
A1  - Mannherz, Hans Georg
A1  - Sequeira, Vasco
A1  - Mügge, Andreas
A1  - Leichert, Lars I.
A1  - Sossalla, Samuel
A1  - Hamdani, Nazha
T1  - The interplay between S-glutathionylation and phosphorylation of cardiac troponin I and myosin binding protein C in end-stage human failing hearts
JF  - Antioxidants
N2  - Oxidative stress is defined as an imbalance between the antioxidant defense system and the production of reactive oxygen species (ROS). At low levels, ROS are involved in the regulation of redox signaling for cell protection. However, upon chronical increase in oxidative stress, cell damage occurs, due to protein, DNA and lipid oxidation. Here, we investigated the oxidative modifications of myofilament proteins, and their role in modulating cardiomyocyte function in end-stage human failing hearts. We found altered maximum Ca\(^{2+}\)-activated tension and Ca\(^{2+}\) sensitivity of force production of skinned single cardiomyocytes in end-stage human failing hearts compared to non-failing hearts, which was corrected upon treatment with reduced glutathione enzyme. This was accompanied by the increased oxidation of troponin I and myosin binding protein C, and decreased levels of protein kinases A (PKA)- and C (PKC)-mediated phosphorylation of both proteins. The Ca\(^{2+}\) sensitivity and maximal tension correlated strongly with the myofilament oxidation levels, hypo-phosphorylation, and oxidative stress parameters that were measured in all the samples. Furthermore, we detected elevated titin-based myocardial stiffness in HF myocytes, which was reversed by PKA and reduced glutathione enzyme treatment. Finally, many oxidative stress and inflammation parameters were significantly elevated in failing hearts compared to non-failing hearts, and corrected upon treatment with the anti-oxidant GSH enzyme. Here, we provide evidence that the altered mechanical properties of failing human cardiomyocytes are partially due to phosphorylation, S-glutathionylation, and the interplay between the two post-translational modifications, which contribute to the development of heart failure.
KW  - myofilament proteins
KW  - oxidative stress
KW  - inflammation
KW  - phosphorylation
KW  - S-glutathionylation
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-242701
SN  - 2076-3921
VL  - 10
IS  - 7
ER  - 
TY  - JOUR
A1  - Wagner, Michael
A1  - Sadek, Mirna S.
A1  - Dybkova, Nataliya
A1  - Mason, Fleur E.
A1  - Klehr, Johann
A1  - Firneburg, Rebecca
A1  - Cachorro, Eleder
A1  - Richter, Kurt
A1  - Klapproth, Erik
A1  - Kuenzel, Stephan R.
A1  - Lorenz, Kristina
A1  - Heijman, Jordi
A1  - Dobrev, Dobromir
A1  - El-Armouche, Ali
A1  - Sossalla, Samuel
A1  - Kämmerer, Susanne
T1  - Cellular mechanisms of the anti-arrhythmic effect of cardiac PDE2 overexpression
JF  - International Journal of Molecular Sciences
N2  - Background: Phosphodiesterases (PDE) critically regulate myocardial cAMP and cGMP levels. PDE2 is stimulated by cGMP to hydrolyze cAMP, mediating a negative crosstalk between both pathways. PDE2 upregulation in heart failure contributes to desensitization to β-adrenergic overstimulation. After isoprenaline (ISO) injections, PDE2 overexpressing mice (PDE2 OE) were protected against ventricular arrhythmia. Here, we investigate the mechanisms underlying the effects of PDE2 OE on susceptibility to arrhythmias. Methods: Cellular arrhythmia, ion currents, and Ca\(^{2+}\)-sparks were assessed in ventricular cardiomyocytes from PDE2 OE and WT littermates. Results: Under basal conditions, action potential (AP) morphology were similar in PDE2 OE and WT. ISO stimulation significantly increased the incidence of afterdepolarizations and spontaneous APs in WT, which was markedly reduced in PDE2 OE. The ISO-induced increase in I\(_{CaL}\) seen in WT was prevented in PDE2 OE. Moreover, the ISO-induced, Epac- and CaMKII-dependent increase in I\(_{NaL}\) and Ca\(^{2+}\)-spark frequency was blunted in PDE2 OE, while the effect of direct Epac activation was similar in both groups. Finally, PDE2 inhibition facilitated arrhythmic events in ex vivo perfused WT hearts after reperfusion injury. Conclusion: Higher PDE2 abundance protects against ISO-induced cardiac arrhythmia by preventing the Epac- and CaMKII-mediated increases of cellular triggers. Thus, activating myocardial PDE2 may represent a novel intracellular anti-arrhythmic therapeutic strategy in HF.
KW  - PDE2
KW  - arrhythmia
KW  - CaMKII
KW  - heart failure
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-285888
SN  - 1422-0067
VL  - 22
IS  - 9
ER  -