Protein kinase inhibition exerts cardioprotective effects in myocardial ischemia/reperfusion via inhibition of superoxide release

Author(s):  
L.H. Young ◽  
Y. Ikeda ◽  
A.M. Lefer
2015 ◽  
Vol 117 (suppl_1) ◽  
Author(s):  
Xuejun Wang ◽  
Erin J Terpstra ◽  
Eduardo Callegari ◽  
Chengjun Hu ◽  
Hanming Zhang ◽  
...  

Cardiac proteasome functional insufficiency is implicated in a large subset of heart disease and has been experimentally demonstrated to play an essential role in cardiac proteotoxicity, including desmin-related cardiomyopathy and myocardial ischemia-reperfusion (I-R) injury. Pharmacological inhibition of phosphodiesterase 5 (PDE5) via sildenafil for example, which can stabilize cGMP and thereby increase cGMP-dependent protein kinase (PKG) activity, is consistently reported to protect against I-R injury; however, the underlying mechanism is not fully understood. We have recently discovered that PKG activation enhances proteasomal degradation of misfolded proteins (Ranek, et al. Circulation 2013), prompting us to hypothesize that proteasome-priming may contribute to cardioprotection-induced by PDE5 inhibition. Here we used a cardiomyocyte-restricted proteasome inhibition transgenic mouse line (Tg) and non-Tg (Ntg) littermates to interrogate the action of sildenafil on I-R injury created by left anterior descending artery (LAD) ligation (30 min) and release (24 hr). Sildenafil was administered 30 min before LAD ligation. Results showed that (1) the 26S proteasome activity of the Ntg I-R hearts was significantly elevated by sildenafil but this elevation was blocked in the Tg line; (2) the infarct size reduction by sildenafil treatment in Ntg mice was completely abolished in the Tg mice with the same treatment; and (3) systolic and diastolic function impairment after I/R was markedly attenuated in sildenafil-treated Ntg mice, but not in the sildenafil-treated Tg mice. Additionally, immunoprecipitation assays show that PKG interacted with the proteasome in cultured cardiomyocytes, and this interaction appeared to be augmented by sildenafil treatment. Moreover, in vitro incubation of active PKG with purified human 26S proteasomes increased proteasome peptidase activities and the phosphorylation at specific serine residues of a 19S proteasome subunit as revealed by “gel-free” nano-LC-MS/MS. We conclude that active PKG directly interacts with, phosphorylates, and increases the activities of, the proteasome and that proteasome priming mediates to cardioprotection of PDE5 inhibition against I-R injury.


2018 ◽  
Vol 27 (8) ◽  
pp. 1256-1268 ◽  
Author(s):  
Tianyu Li ◽  
Yunshu Su ◽  
Xiongli Yu ◽  
Durgahee S.A. Mouniir ◽  
Jackson Ferdinand Masau ◽  
...  

Stem cell transplantation represents a promising therapeutic approach for myocardial ischemia/reperfusion (I/R) injury, where cortical bone-derived stem cells (CBSCs) stand out and hold superior cardioprotective effects on myocardial infarction than other types of stem cells. However, the molecular mechanism underlying CBSCs function on myocardial I/R injury is poorly understood. In a previous study, we reported that Trop2 (trophoblast cell-surface antigen 2) is expressed exclusively on the CBSCs membrane, and is involved in regulation of proliferation and differentiation of CBSCs. In this study, we found that the Trop2 is essential for the ameliorative effects of CBSCs on myocardial I/R-induced heart damage via promoting angiogenesis and inhibiting cardiomyocytes apoptosis in a paracrine manner. Trop2 is required for the colonization of CBSCs in recipient hearts. When Trop2 was knocked out, CBSCs largely lost their functions in lowering myocardial infarction size, improving heart function, enhancing capillary density, and suppressing myocardial cell death. Mechanistically, activating the AKT/GSK3β/β-Catenin signaling axis contributes to the essential role of Trop2 in CBSCs-rendered cardioprotective effects on myocardial I/R injury. In conclusion, maintaining the expression and/or activation of Trop2 in CBSCs might be a promising strategy for treating myocardial infarction, I/R injury, and other related heart diseases.


2000 ◽  
Vol 279 (1) ◽  
pp. H329-H338 ◽  
Author(s):  
Feng Gao ◽  
Theodore A. Christopher ◽  
Bernard L. Lopez ◽  
Eitan Friedman ◽  
Guoping Cai ◽  
...  

The purpose of this study was to determine whether the protective effects of adenosine on myocardial ischemia-reperfusion injury are altered with age, and if so, to clarify the mechanisms that underlie this change related to nitric oxide (NO) derived from the vascular endothelium. Isolated perfused rat hearts were exposed to 30 min of ischemia and 60 min of reperfusion. In the adult hearts, administration of adenosine (5 μmol/l) stimulated NO release (1.06 ± 0.19 nmol · min−1 · g−1, P < 0.01 vs. vehicle), increased coronary flow, improved cardiac functional recovery (left ventricular developed pressure 79 ± 3.8 vs. 57 ± 3.1 mmHg in vehicle, P < 0.001; maximal rate of left ventricular pressure development 2,385 ± 103 vs. 1,780 ± 96 in vehicle, P < 0.001), and reduced myocardial creatine kinase loss (95 ± 3.9 vs. 159 ± 4.6 U/100 mg protein, P < 0.01). In aged hearts, adenosine-stimulated NO release was markedly reduced (+0.42 ± 0.12 nmol · min−1 · g−1 vs. vehicle), and the cardioprotective effects of adenosine were also attenuated. Inhibition of NO production in the adult hearts significantly decreased the cardioprotective effects of adenosine, whereas supplementation of NO in the aged hearts significantly enhanced the cardioprotective effects of adenosine. The results show that the protective effects of adenosine on myocardial ischemia-reperfusion injury are markedly diminished in aged animals, and that the loss in NO release in response to adenosine may be at least partially responsible for this age-related alteration.


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