Abstract 423: Proteasome Priming by Protein Kinase G Protects Against Myocardial Ischemia-reperfusion Injury

2015 ◽  
Vol 117 (suppl_1) ◽  
Author(s):  
Xuejun Wang ◽  
Erin J Terpstra ◽  
Eduardo Callegari ◽  
Chengjun Hu ◽  
Hanming Zhang ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Myocardial Ischemia ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Underlying Mechanism ◽  
26S Proteasome ◽  
Transgenic Mouse Line ◽  
Pde5 Inhibition ◽  
Myocardial Ischemia Reperfusion

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.

The cardioprotection of dihydrotanshinone I against myocardial ischemia–reperfusion injury via inhibition of arachidonic acid ω-hydroxylase

2016 ◽  
Vol 94 (12) ◽  
pp. 1267-1275 ◽  
Author(s):  
Yidan Wei ◽  
Meijuan Xu ◽  
Yi Ren ◽  
Guo Lu ◽  
Yangmei Xu ◽  
...  
Keyword(s):  
Arachidonic Acid ◽  
Myocardial Ischemia ◽  
Reperfusion Injury ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Protective Effects ◽  
Myocardial Ischemia Reperfusion Injury ◽  
Myocardial Ischemia Reperfusion

Arachidonic acid (AA) is a precursor that is metabolized by several enzymes to many biological eicosanoids. Accumulating data indicate that the ω-hydroxylation metabolite of AA, 20-hydroxyeicosatetraenoic acid (20-HETE), is considered to be involved in the myocardial ischemia–reperfusion injury (MIRI). The inhibitors of AA ω-hydroxylase, however, are demonstrated to exhibit protective effects on MIRI. Dihydrotanshinone I (DI), a bioactive constituent of danshen, is proven to be a potent inhibitor of AA ω-hydroxylase by our preliminary study in vitro. The purpose of the present study was to investigate the cardioprotection of DI against MIRI and its effects on the concentrations of 20-HETE in vivo. Rats subjected to 30 min of ischemia followed by 24 h of reperfusion were assigned to intravenously receive vehicle (sham and ischemia–reperfusion), low (1 mg/kg), middle (2 mg/kg), or high (4 mg/kg) doses of DI before reperfusion. The results demonstrated that DI treatment could improve cardiac function, reduce infarct size, ameliorate the variations in myocardial zymogram and histopathological disorders, decrease 20-HETE generation, and regulate apoptosis-related protein in myocardial ischemia–reperfusion rats. These findings suggested DI could exert considerable cardioprotective action on MIRI by the attenuation of 20-HETE generation, subsequent myocardial injury, and apoptosis through inhibition on AA ω-hydroxylase.

scholarly journals Anastatin Derivatives Alleviate Myocardial Ischemia-Reperfusion Injury via Antioxidative Properties

Molecules ◽  
2021 ◽  
Vol 26 (16) ◽  
pp. 4779
Author(s):  
Ying Fu ◽  
Cai Zhao ◽  
Rengui Saxu ◽  
Chaoran Yao ◽  
Lianbo Zhao ◽  
...  
Keyword(s):  
Myocardial Ischemia ◽  
Ischemia Reperfusion Injury ◽  
Antioxidant Activities ◽  
Ischemia Reperfusion ◽  
Radical Scavenging ◽  
Serum Lactate Dehydrogenase ◽  
Antioxidant Power ◽  
Myocardial Ischemia Reperfusion

(±)-Anastatins A and B are flavonoids isolated from Anastatica hierochuntica. In a previous study, twenty-four di- and tri-substituted novel derivatives of anastatins were designed and their preliminary antioxidant activities were evaluated. In the present study, the protective effect of myocardial ischemia-reperfusion (I/R) and the systematic antioxidant capacity of 24 derivatives were further studied. Compound 13 was the most potent among all the compounds studied, which increased the survival of H9c2 cells to 80.82%. The antioxidant capability of compound 13 was evaluated in ferric reducing antioxidant power, 2,2’-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging, and 2,2-diphenyl-1-picrylhydrazyl assays. It was observed that compound 13 significantly reduced infarcted areas and improved histopathological and electrocardiogram changes in rats with myocardial I/R injury. Moreover, compound 13 decreased the leakage rates of serum lactate dehydrogenase, creatine kinase, and malonyldialdehyde from rat myocardial tissues and increased the level of glutathione and superoxide dismutase activities following myocardial I/R injury in rats. Taken together, we concluded that compound 13 had potent cardioprotective effects against myocardial I/R injury both in vitro and in vivo owing to its extensive antioxidant activities.

scholarly journals Calenduloside E Ameliorates Myocardial Ischemia-Reperfusion Injury through Regulation of AMPK and Mitochondrial OPA1

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Min Wang ◽  
Rui-ying Wang ◽  
Jia-hui Zhou ◽  
Xue-heng Xie ◽  
Gui-bo Sun ◽  
...  
Keyword(s):  
Myocardial Ischemia ◽  
Reperfusion Injury ◽  
Ischemia Reperfusion Injury ◽  
Mitochondrial Dynamics ◽  
Ischemia Reperfusion ◽  
Protective Effects ◽  
Myocardial Ischemia Reperfusion Injury ◽  
Myocardial Ischemia Reperfusion

Calenduloside E (CE) is a natural triterpenoid saponin isolated from Aralia elata (Miq.) Seem., a well-known traditional Chinese medicine. Our previous studies have shown that CE exerts cardiovascular protective effects both in vivo and in vitro. However, its role in myocardial ischemia/reperfusion injury (MIRI) and the mechanism involved are currently unknown. Mitochondrial dynamics play a key role in MIRI. This study investigated the effects of CE on mitochondrial dynamics and the signaling pathways involved in myocardial ischemia/reperfusion (MI/R). The MI/R rat model and the hypoxia/reoxygenation (H/R) cardiomyocyte model were established in this study. CE exerted significant cardioprotective effects in vivo and in vitro by improving cardiac function, decreasing myocardial infarct size, increasing cardiomyocyte viability, and inhibiting cardiomyocyte apoptosis associated with MI/R. Mechanistically, CE restored mitochondrial homeostasis against MI/R injury through improved mitochondrial ultrastructure, enhanced ATP content and mitochondrial membrane potential, and reduced mitochondrial permeability transition pore (MPTP) opening, while promoting mitochondrial fusion and preventing mitochondrial fission. However, genetic silencing of OPA1 by siRNA abolished the beneficial effects of CE on cardiomyocyte survival and mitochondrial dynamics. Moreover, we demonstrated that CE activated AMP-activated protein kinase (AMPK) and treatment with the AMPK inhibitor, compound C, abolished the protective effects of CE on OPA1 expression and mitochondrial function. Overall, this study demonstrates that CE is effective in mitigating MIRI by modulating AMPK activation-mediated OPA1-related mitochondrial fusion.

scholarly journals PLCE1 promotes myocardial ischemia–reperfusion injury in H/R H9c2 cells and I/R rats by promoting inflammation

2019 ◽  
Vol 39 (7) ◽  
Author(s):  
WenHua Li ◽  
Yong Li ◽  
Ying Chu ◽  
WeiMin Wu ◽  
QiuHua Yu ◽  
...  
Keyword(s):  
Myocardial Ischemia ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Underlying Mechanism ◽  
H9c2 Cell ◽  
Injury Model ◽  
Tnf Α ◽  
Myocardial Ischemia Reperfusion Injury ◽  
Artery Disease ◽  
Myocardial Ischemia Reperfusion

Abstract Myocardial ischemia–reperfusion (I/R) injury is a major contributor to the morbidity and mortality associated with coronary artery disease. How to ensure the recovery of blood supply to ischemic myocardial tissue while avoiding or reducing I/R injury remains a critical problem in clinical practice. In the present study, we examined the function of phospholipase C ϵ-1 (PLCE1) by an H9c2 H/R (H/R, hypoxia–reoxygenation) model and a rat myocardial I/R injury model. The expression of PLCE1 and its effect on I/R injury-induced inflammatory response as well as its possible underlying mechanism were investigated. Our results have shown that PLCE1 was progressively increased along with the increase in hypoxia time in the H/R H9c2 and HL-1 cells. In myocardial I/R rats, PLCE1 presented a low expression level in the sham group, however, it was increased sharply in the I/R group. Overexpression of PLCE1 promoted the expression of IL-6, TNF-α, and IL-1α, and decreased the expression of IL-10. Knockdown of PLCE1 decreased the expression of IL-6, TNF-α, and IL-1α, and increased the expression of IL-10. Furthermore, overexpression of PLCE1 increased the phosphorylation of p38, ERK1/2, and nuclear factor-κ B (NF-κB) P65 while knockdown of PLCE1 inhibited their phosphorylation. In conclusion, the present study provided evidence that PLCE1 was up-regulated in H/R H9c2 cell and I/R rat. Overexpression of PLCE1 promoted the inflammatoion via activation of the NF-κB signaling pathway.

scholarly journals p38-Regulated/activated protein kinase plays a pivotal role in protecting heart against ischemia-reperfusion injury and preserving cardiac performance

2019 ◽  
Vol 317 (3) ◽  
pp. C525-C533 ◽  
Author(s):  
Yu Tina Zhao ◽  
Jianfeng Du ◽  
Naohiro Yano ◽  
Hao Wang ◽  
Jianguo Wang ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Myocardial Ischemia ◽  
Reperfusion Injury ◽  
Ischemia Reperfusion Injury ◽  
Interstitial Fibrosis ◽  
Ischemia Reperfusion ◽  
Left Ventricular ◽  
Cardiac Performance ◽  
Myocardial Ischemia Reperfusion Injury ◽  
Myocardial Ischemia Reperfusion

p38-Regulated/activated protein kinase (PRAK) plays a critical role in modulating cellular survival and biological function. However, the function of PRAK in the regulation of myocardial ischemic injury remains unknown. This study is aimed at determining the function of PRAK in modulating myocardial ischemia-reperfusion injury and myocardial remodeling following myocardial infarction. Hearts were isolated from adult male homozygous PRAK−/− and wild-type mice and subjected to global ischemia-reperfusion injury in Langendorff isolated heart perfusion. PRAK−/− mice mitigated postischemic ventricular functional recovery and decreased coronary effluent. Moreover, the infarct size in the perfused heart was significantly increased by deletion of PRAK. Western blot showed that deletion of PRAK decreased the phosphorylation of ERK1/2. Furthermore, the effect of deletion of PRAK on myocardial function and remodeling was also examined on infarcted mice in which the left anterior descending artery was ligated. Echocardiography indicated that PRAK−/− mice had accelerated left ventricular systolic dysfunction, which was associated with increased hypertrophy in the infarcted area. Deletion of PRAK augmented interstitial fibrosis and terminal deoxynucleotidyl transferase nick-end labeling (TUNEL)-positive myocytes. Furthermore, immunostaining analysis shows that CD31-postive vascular density and α-smooth muscle actin capillary staining decreased significantly in PRAK−/− mice. These results indicate that deletion of PRAK enhances susceptibility to myocardial ischemia-reperfusion injury, attenuates cardiac performance and angiogenesis, and increases interstitial fibrosis and apoptosis in the infarcted hearts.

Abstract P273: Enhancement of Proteasomal Function Protects Against Proteinopathy and Myocardial Ischemia-Reperfusion Injury in Mice

2011 ◽  
Vol 109 (suppl_1) ◽  
Author(s):  
Jie Li ◽  
Kathleen M Horak ◽  
Huabo Su ◽  
Atsushi Sanbe ◽  
Jeffrey Robbins ◽  
...  
Keyword(s):  
Myocardial Ischemia ◽  
Cardiac Function ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Protein Accumulation ◽  
Pathogenic Role ◽  
Littermate Control ◽  
Myocardial Ischemia Reperfusion ◽  
Cultured Cardiomyocytes

The ubiquitin-proteasome system degrades most intracellular proteins, including misfolded proteins. Proteasome functional insufficiency (PFI) was observed in experimental proteinopathies and implicated in many human common diseases but its pathogenic role has not been established because a measure to enhance proteasome function in the cell has not been reported until very recently. We have recently discovered that overexpression of proteasome activator 28α (PA28α) enhances proteasome-mediated removal of abnormal proteins in the cell and protects against oxidative stress in cultured cardiomyocytes ( FASEB J 2011; 25(3):883-93 ). Here we have extended the in vitro discoveries to intact animals. First, we created inducible transgenic mice with cardiomyocyte-restricted PA28α overexpression (CR-PA28αOE). CR-PA28αOE does not alter the homeostasis of normal proteins and cardiac function but increases the degradation of a surrogate misfolded protein in the heart. This marks the establishment of the first animal model of benign enhancement of proteasomal function. Second, by breeding CR-PA28αOE mice with a well-established mouse model of mutant αB-crystallin (CryAB R120G ) based desmin-related cardiomyopathy, a bona fide cardiac proteinopathy, we demonstrate that CR-PA28αOE markedly reduced aberrant protein aggregation and cardiac hypertrophy and the lifespan of the animals significantly increased. Furthermore, PA28α knockdown promoted, while PA28αOE attenuated, CryAB R120G protein accumulation in cultured cardiomyocytes. Finally, we tested the effect of proteasome functional enhancement on myocardial ischemia/reperfusion (I/R) injury induced by ligation and subsequent release of the left anterior descending artery. We found that the infarct size was significantly reduced and cardiac function recovery during reperfusion was markedly facilitated in the CR-PA28αOE mice, compared with their littermate control mice. We conclude that (1) benign enhancement of cardiac proteasome function can be achieved by CR-PA28αOE; (2) PFI plays a major pathogenic role in proteinopathy and myocardial I/R injury; and (3) upregulating PA28α is potentially a novel therapeutic strategy for proteinopathies and disease alike.

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