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Ryanodine receptor leak mediated by caspase-8 activation leads to left ventricular injury after myocardial ischemia-reperfusion.

ABSTRACT: Myocardial ischemic disease is the major cause of death worldwide. After myocardial infarction, reperfusion of infracted heart has been an important objective of strategies to improve outcomes. However, cardiac ischemia/reperfusion (I/R) is characterized by inflammation, arrhythmias, cardiomyocyte damage, and, at the cellular level, disturbance in Ca(2+) and redox homeostasis. In this study, we sought to determine how acute inflammatory response contributes to reperfusion injury and Ca(2+) homeostasis disturbance after acute ischemia. Using a rat model of I/R, we show that circulating levels of TNF-? and cardiac caspase-8 activity were increased within 6 h of reperfusion, leading to myocardial nitric oxide and mitochondrial ROS production. At 1 and 15 d after reperfusion, caspase-8 activation resulted in S-nitrosylation of the RyR2 and depletion of calstabin2 from the RyR2 complex, resulting in diastolic sarcoplasmic reticulum (SR) Ca(2+) leak. Pharmacological inhibition of caspase-8 before reperfusion with Q-LETD-OPh or prevention of calstabin2 depletion from the RyR2 complex with the Ca(2+) channel stabilizer S107 ("rycal") inhibited the SR Ca(2+) leak, reduced ventricular arrhythmias, infarct size, and left ventricular remodeling after 15 d of reperfusion. TNF-?-induced caspase-8 activation leads to leaky RyR2 channels that contribute to myocardial remodeling after I/R. Thus, early prevention of SR Ca(2+) leak trough normalization of RyR2 function is cardioprotective.

SUBMITTER: Fauconnier J

PROVIDER: S-EPMC3156220 | biostudies-literature | 2011 Aug

REPOSITORIES: biostudies-literature

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Ryanodine receptor leak mediated by caspase-8 activation leads to left ventricular injury after myocardial ischemia-reperfusion.

Fauconnier Jérémy J Meli Albano C AC Thireau Jérôme J Roberge Stephanie S Shan Jian J Sassi Yassine Y Reiken Steven R SR Rauzier Jean-Michel JM Marchand Alexandre A Chauvier David D Cassan Cécile C Crozier Christine C Bideaux Patrice P Lompré Anne-Marie AM Jacotot Etienne E Marks Andrew R AR Lacampagne Alain A

Proceedings of the National Academy of Sciences of the United States of America 20110725 32

Myocardial ischemic disease is the major cause of death worldwide. After myocardial infarction, reperfusion of infracted heart has been an important objective of strategies to improve outcomes. However, cardiac ischemia/reperfusion (I/R) is characterized by inflammation, arrhythmias, cardiomyocyte damage, and, at the cellular level, disturbance in Ca(2+) and redox homeostasis. In this study, we sought to determine how acute inflammatory response contributes to reperfusion injury and Ca(2+) homeo ...[more]

PMID: 21788490

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Project description:Background: Guanxin Danshen formulation (GXDSF) is a traditional Chinese herbal recipe recorded in the Chinese Pharmacopeia since 1995 edition, which consists of Salviae miltiorrhizae Radix et Rhizoma, Notoginseng Radix et Rhizoma and Dalbergiae odoriferae Lignum. Our previous research suggested GXDSF had positive effect on cardiovascular disease. Therefore, the aim of this study was to elucidate the effects of GXDSF on myocardial ischemia reperfusion injury-induced left ventricular remodelling (MIRI-LVR). Methods: The effects of GXDSF on cardiac function were detected by haemodynamics and echocardiograms. The effects of GXDSF on biochemical parameters (AST, LDH and CK-MB) were analyzed. Histopathologic examinations were performed to evaluate the effect of GXDSF on cardiac structure. In addition, the Traditional Chinese Medicine Systems Pharmacology (TCMSP) database was used to predict the main target of GXDSF. Target validation was conducted by using western blots and immunofluorescent double staining assays. Results: We found that +dp/dt and LVSP were significantly elevated in the GXDSF-treated groups compared with the MIRI-LVR model group. Left ventricular ejection fraction (LVEF) and left ventricular fractional shortening (LVFS) were increased in the GXDSF-treated groups compared with the model group. All biochemical parameters (AST, LDH and CK-MB) were considerably decreased in the GXDSF-treated groups compared with the model group. Fibrosis parameters (collagen I and III, α-SMA, and left ventricular fibrosis percentage) were decreased to different degrees in the GXDSF-treated groups compared with the model group, and the collagen III/I ratio was elevated by the same treatments. TCMSP database prediction and western blot results indicated that estrogen receptor β (ERβ) could be the main target of GXDSF. PHTPP, a selective antagonist of ERβ, could inhibit the expression of ERβ and the phosphorylation of PI3K and Akt in myocardial tissue induced by GXDSF, and partly normalize the improving effects of GXDSF on +dp/dt, LVEF, LVFS, LDH, CK-MB, α-SMA and myocardial fibrosis. Conclusion: Collectively, GXDSF showed therapeutic potential for use in the prevention and treatment of myocardial ischemia reperfusion injury-induced ventricular remodeling by upregulating ERβ via PI3K/Akt signaling. Moreover, these findings may be valuable in understand the mechanism of disease and provide a potential therapy of MIRI-IVR.

Project description:Postconditioning and cyclosporine A prevent mitochondrial permeability transition pore opening providing cardioprotection during ischemia/reperfusion. Whether microvascular obstruction is affected by these interventions is largely unknown. Pigs subjected to coronary occlusion for 1 h followed by 3 h of reperfusion were assigned to control (n = 8), postconditioning (n = 9) or cyclosporine A intravenous infusion 10-15 min before the end of ischemia (n = 8). Postconditioning was induced by 8 cycles of repeated 30-s balloon inflation and deflation. After 3 h of reperfusion magnetic resonance imaging, triphenyltetrazolium chloride/Evans blue staining and histopathology were performed. Microvascular obstruction (MVO, percentage of gadolinium-hyperenhanced area) was measured early (3 min) and late (12 min) after contrast injection. Infarct size with double staining was smaller in cyclosporine (46.2 ± 3.1%, P = 0.016) and postconditioning pigs (47.6 ± 3.9%, P = 0.008) versus controls (53.8 ± 4.1%). Late MVO was significantly reduced by cyclosporine (13.9 ± 9.6%, P = 0.047) but not postconditioning (23.6 ± 11.7%, P = 0.66) when compared with controls (32.0 ± 16.9%). Myocardial blood flow in the late MVO was improved with cyclosporine versus controls (0.30 ± 0.06 vs 0.21 ± 0.03 ml/g/min, P = 0.002) and was inversely correlated with late-MVO extent (R(2) = 0.93, P < 0.0001). Deterioration of left ventricular ejection fraction (LVEF) between baseline and 3 h of reperfusion was smaller with cyclosporine (-7.9 ± 2.4%, P = 0.008) but not postconditioning (-12.0 ± 5.5%, P = 0.22) when compared with controls (-16.4 ± 5.5%). In the three groups, infarct size (β = -0.69, P < 0.001) and late MVO (β = -0.33, P = 0.02) were independent predictors of LVEF deterioration following ischemia/reperfusion (R(2) = 0.73, P < 0.001). Despite both cyclosporine A and postconditioning reduce infarct size, only cyclosporine A infusion had a beneficial effect on microvascular damage and was associated with better preserved LV function when compared with controls.

Project description:ObjectiveThe incidence of acute myocardial infarction (AMI) is increasing yearly. With the use of thrombolysis or percutaneous coronary intervention (PCI), the mortality rate of acute myocardial infarction has been significantly reduced. However, reperfusion can cause additional myocardial injury. There is still a lack of effective drugs to treat I/R injury, and it is urgent to find new therapeutic drugs.MethodsIn this study, network pharmacology was used to predict potential targets and biological processes involved in Muscone-mediated treatment of acute myocardial infarction. To model ischemia‒reperfusion injury, a hypoxia-reoxygenation model and in vivo ischemia‒reperfusion injury C57BL/6 mice model was constructed. Mice were treated with Muscone i.p. for 4 weeks. We detected the cardiac function on day 28.The expression levels of the apoptotic proteins Caspase-3 and Bax and the anti-apoptotic protein Bcl-2 were detected by immunoblotting after Muscone treatment of AC16 cells and in vivo. Additionally, the gene expression levels of the PUMA and p53 were analyzed by qRT‒PCR. Molecular docking was used to evaluate the binding energy between Muscone and NLRP3-related proteins. Immunoblotting and qRT‒PCR were used to assess the expression levels of NLRP3 signaling pathway-related proteins (NLRP3, ASC, and Caspase-1) and the NLRP3 gene, respectively. Moreover, the extracellular acidification rate of AC16 cells was measured using the Seahorse system to evaluate glycolysis levels after Muscone treatment. The expression of the key glycolytic enzyme PKM2 was analyzed by immunoblotting and qRT‒PCR. Finally, ChIP‒qPCR was performed to determine the levels of histone modifications (H3K4me3, H3K27me3, and H2AK119Ub) in the PKM2 promoter region.ResultsGO functional enrichment analysis revealed that muscone was involved in regulating the biological processes (BP) of AMI, which mainly included negative regulation of the apoptosis signaling pathway, the response to lipopolysaccharide, and blood pressure regulation. The cellular components (CC) involved in muscone-mediated regulation of AMI mainly included lipid rafts, membrane microdomains, and membrane regions. The molecular functions (MF) involved in muscone-mediated regulation of AMI mainly included oxidoreductase activity, nuclear receptor activity, and transcription factor activity. In vitro results indicated that muscone treatment could inhibit the expression levels of Bax and Caspase-3 in AC16 cells after ischemia‒reperfusion while increasing the expression level of the antiapoptotic protein Bcl-2. Muscone significantly suppressed the transcription levels of p53 and PUMA in AC16 cells. Molecular docking suggested that muscone could bind well with the Cryo-EM structure of NEK7(PDB ID:6NPY). Further investigation of inflammatory pathways revealed that muscone could inhibit the expression level of NLRP3 in AC16 cells and reduce the expression levels of Caspase-1 and Caspase recruitment domain. Fluorescent quantitative PCR experiments showed that muscone significantly inhibited the transcription of NLRP3. Moreover, we found that muscone could enhance the glycolytic efficiency of AC16 cells, which may be related to the increased protein expression of PKM2 in AC16 cells. Fluorescent quantitative PCR showed that muscone could increase the transcription level of PKM2. Chromatin immunoprecipitation assays showed that muscone treatment increased the expression level of H3K4me3 in the PKM2 promoter region and inhibited the levels of H3K27me3 and H2AK119Ub in the PKM2 promoter region.ConclusionMuscone promoted myocardial glycolysis and inhibited NLRP3 pathway activation to improve myocardial ischemia‒reperfusion injury.

Project description:Myocardial ischemia-reperfusion (I/R) results in the generation of free radicals, accumulation of lipid peroxidation-derived unsaturated aldehydes, variable angina (pain), and infarction. The transient receptor potential ankyrin 1 (TRPA1) mediates pain signaling and is activated by unsaturated aldehydes, including acrolein and 4-hydroxynonenal. The contribution of TRPA1 (a Ca2+-permeable channel) to I/R-induced myocardial injury is unknown. We tested the hypothesis that cardiac TRPA1 confers myocyte sensitivity to aldehyde accumulation and promotes I/R injury. Although basal cardiovascular function in TRPA1-null mice was similar to that in wild-type (WT) mice, infarct size was significantly smaller in TRPA1-null mice than in WT mice (34.1?±?9.3 vs. 14.3?±?9.9% of the risk region, n = 8 and 7, respectively, P < 0.05), despite a similar I/R-induced area at risk (40.3?±8.4% and 42.2?±?11.3% for WT and TRPA1-null mice, respectively) after myocardial I/R (30 min of ischemia followed by 24 h of reperfusion) in situ. Positive TRPA1 immunofluorescence was present in murine and human hearts and was colocalized with connexin43 at intercalated disks in isolated murine cardiomyocytes. Cardiomyocyte TRPA1 was confirmed by quantitative RT-PCR, DNA sequencing, Western blot analysis, and electrophysiology. A role of TRPA1 in cardiomyocyte toxicity was demonstrated in isolated cardiomyocytes exposed to acrolein, an I/R-associated toxin that induces Ca2+ accumulation and hypercontraction, effects significantly blunted by HC-030031, a TRPA1 antagonist. Protection induced by HC-030031 was quantitatively equivalent to that induced by SN-6, a Na+/Ca2+ exchange inhibitor, further supporting a role of Ca2+ overload in acrolein-induced cardiomyocyte toxicity. These data indicate that cardiac TRPA1 activation likely contributes to I/R injury and, thus, that TRPA1 may be a novel therapeutic target for decreasing myocardial I/R injury. NEW & NOTEWORTHY Transient receptor potential ankyrin 1 (TRPA1) activation mediates increased blood flow, edema, and pain reception, yet its role in myocardial ischemia-reperfusion (I/R) injury is unknown. Genetic ablation of TRPA1 significantly decreased myocardial infarction after I/R in mice. Functional TRPA1 in cardiomyocytes was enriched in intercalated disks and contributed to acrolein-induced Ca2+ overload and hypercontraction. These data indicate that I/R activation of TRPA1 worsens myocardial infarction; TRPA1 may be a potential target to mitigate I/R injury.

Project description:Effect of simvastatin on the expression of caspase-3 in myocardial ischemia reperfusion injury in rats was observed to explore the protective effect of caspase-3 through anti-apoptosis mechanism. A total of 48 healthy male SD rats weighing 160-240 g were selected and divided into 4 groups randomly, namely, the blank group, the sham operation group, the ischemia-reperfusion group and the simvastatin group, with 12 rats in each group. The model of SD rats was made by ligation. The loosen ligature made the reperfusion animal model, the occurrence of arrhythmia in the electrocardiogram of lead II in the experimental animal model was observed, and the area of myocardial infarction in the experimental animal models was detected. The number of apoptotic cells was detected by immunohistochemistry, and the expression of caspase-3 was detected by western blotting. The infarct area in the simvastatin group was significantly lower than the ischemia reperfusion group (P<0.05). The positive rate of the expression of caspase-3 and the positive rate of the expression of apoptotic cells in the ischemic reperfusion and simvastatin groups were significantly higher than that of the blank and sham operation groups, and the positive rate of the expression of caspase-3 and apoptotic cells in the simvastatin group was significantly lower than that of the ischemia-reperfusion group (P<0.05). The arrhythmia score of the simvastatin group was significantly lower than that of the ischemia-reperfusion group (P<0.05). Compared with the blank and sham operation groups, the expression of caspase-3 protein in the ischemia-reperfusion and simvastatin groups was significantly increased, and the expression of caspase-3 protein in the simvastatin group was significantly lower than that of the ischemia reperfusion group (P<0.05). Simvastatin has a protective effect on myocardial ischemia-reperfusion injury, which may be related to the reduction of caspase-3 expression and inhibition of apoptosis.

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Ryanodine receptor leak mediated by caspase-8 activation leads to left ventricular injury after myocardial ischemia-reperfusion.

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Ryanodine receptor leak mediated by caspase-8 activation leads to left ventricular injury after myocardial ischemia-reperfusion.

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