Abstract 343: Activation of ROR-α, but not ROR-β or ROR-γ, Protects against Myocardial Ischemia/Reperfusion Injury

2014 ◽  
Vol 115 (suppl_1) ◽  
Author(s):  
Jun Pu ◽  
Ben He ◽  
Erhe Gao ◽  
Xinliang Ma ◽  
Yajing Wang
Keyword(s):  
Endoplasmic Reticulum ◽  
Myocardial Ischemia ◽  
Cardiac Function ◽  
Infarct Size ◽  
Er Stress ◽  
Ischemia Reperfusion ◽  
Specific Gene ◽  
Mitochondrial Impairment ◽  
Nitrative Stress ◽  
Myocardial Ischemia Reperfusion

Objectives: The RAR-related orphan receptors (RORs) are members of the nuclear receptor superfamily that play a pivotal role in many physiological processes, including regulation of the circadian rhythm, development, metabolism and immune function. Three different but highly homologous ROR isoforms, ROR-α, -β, and -γ, have been discovered separately. However, the functional roles of RORs in the heart have never been investigated. We investigate the role of RORs in the pathophysiology of acute myocardial ischemia/ reperfusion (MI/R) injury. Methods and Results: The endogenous RORα, but not RORβ or RORγ, was significantly upregulated after MI/R. Synthetic ROR agonists SR1078 and SR3335 reduced myocardial infarction and improved contractile function after MI/R. Mechanistically, ROR activation inhibited endoplasmic reticulum (ER) stress, attenuated mitochondrial impairment, reduced cardiomyocyte apoptosis, and inhibited MI/R-induced autophagy dysfunction. Moreover, ROR activation inhibited MI/R-induced oxidative stress and nitrative stress. The aforementioned cardioprotective effects of ROR agonists were impaired in the setting of cardiac-specific gene silencing of RORα, but not RORβ or RORγ subtype. In contrast, adenovirus-mediated cardiac RORα overexpression, but not RORβ or RORγ overexpression, decreased myocardial infarct size and improved cardiac function through attenuating oxidative/nitrative stress and inhibiting ER stress, mitochondrial impairment, and autophagy dysfunction. Finally, RORα sg/sg mice (loss-of-function mutation in RORα), but not RORβ-null or RORγ-null mice, increased MI/R injury (greater apoptosis, larger infarct size, and poor cardiac function), exacerbated MI/R-induced oxidative/nitrative stress, and aggravated endoplasmic-reticulum stress, mitochondrial dysfunction, and autophagy dysfunction. Conclusion: Our study provides the first direct evidence that RORα acts as a novel endogenous cardioprotective receptor against myocardial injury. RORα, but not RORβ or RORγ, is a novel cardiac protective receptor against MI/R injury, supporting for the drug development strategies specifically targeting RORα for the treatment of ischemic heart disease.

scholarly journals Suppression of Long Non-Coding RNA LINC00652 Restores Sevoflurane-Induced Cardioprotection Against Myocardial Ischemia-Reperfusion Injury by Targeting GLP-1R Through the cAMP/PKA Pathway in Mice

2018 ◽  
Vol 49 (4) ◽  
pp. 1476-1491 ◽  
Author(s):  
Shu-Bo  Zhang ◽  
Tie-Jun Liu ◽  
Guo-Hua Pu ◽  
Bao-Yong Li ◽  
Xiao-Zeng Gao ◽  
...  
Keyword(s):  
Myocardial Ischemia ◽  
Cardiac Function ◽  
Infarct Size ◽  
Ischemia Reperfusion ◽  
Myocardial Cells ◽  
Non Coding Rna ◽  
Tnf Α ◽  
Myocardial Ischemia Reperfusion ◽  
Pka Pathway ◽  
Long Non Coding Rna

Background/Aims: Long non-coding RNA (lncRNA) and glucagon-like peptide 1 receptor (GLP-1R) are crucial for heart development and for adult heart structural maintenance and function. Herein, we performed a study to explore the effect of lncRNA LINC00652 (LINC00652) on myocardial ischemia-reperfusion (I/R) injury by targeting GLP-1R through the cyclic adenosine monophosphate-protein kinase A (cAMP/PKA) pathway. Methods: Bioinformatics software was used to screen the long-chain non-coding RNAs associated with myocardial ischemia-reperfusion and to predict target genes. The mRNA and protein levels of LINC00652, GLP-1R and CREB were detected by RT-qPCR and western blotting. In order to identify the interaction between LINC00652 and myocardial I/R injury, the cardiac function, the hemodynamic changes, the pathological changes of the myocardial tissues, the myocardial infarct size, and the apoptosis of myocardial cells of mice were measured. Meanwhile, the levels of serum IL-1β and TNF-α were detected. Results: LINC00652 was overexpressed in the myocardial cells of mice with myocardial I/R injury. GLP-1R is the target gene of LINC00652. We also determined higher levels of LINC00652 and GLP-1R in the I/R modeled mice. Additionally, si-LINC00652 decreased cardiac pathology, infarct size, apoptosis rates of myocardial cells, and levels of IL-1β and TNF-α, and increased GLP-1R expression cardiac function, normal hemodynamic index, and the expression and phosphorylation of GLP-1R and CREB proteins. Conclusion: Taken together, our key findings of the present highlight LINC00652 inhibits the activation of the cAMP/PKA pathway by targeting GLP-1R to reduce the protective effect of sevoflurane on myocardial I/R injury in mice.

Abstract 16598: The Role of Paraoxonase 2 in Myocardial Ischemia/Reperfusion Injury

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Jingyuan Li ◽  
Victor R Grijalva ◽  
Srinivasa T Reddy ◽  
Mansoureh Eghbali
Keyword(s):  
Myocardial Ischemia ◽  
Infarct Size ◽  
Er Stress ◽  
Reperfusion Injury ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Ros Production ◽  
Myocardial Ischemia Reperfusion Injury ◽  
Myocardial Ischemia Reperfusion

Objectives: Paraoxonases (PON) gene family consists of three proteins PON1, PON2, and PON3. PON2 is an intracellular membrane-associated protein that is widely expressed in vascular cells and many tissues. At the subcellular level, PON2 is localized to both the ER and mitochondria, and protects against oxidative stress. Hypothesis: The aim of this study was to investigate the role of PON2 in myocardial ischemia reperfusion injury. Methods: PON2 deficient (PON2-/-) and WT male mice were subjected to in-vivo ischemia/reperfusion injury. The left anterior descending coronary artery was occluded for 30 min followed by 24 hr of reperfusion. The infarct size, mitochondrial calcium retention capacity (CRC) and reactive oxygen species (ROS) generation were measured. The expression of C/EBP homologous protein (CHOP), GSK3b and phosphate GSK3b protein were examined by Western Blot. The number of animals was 5-7/group and data were expressed as mean±SEM. T test were used for statistical analysis. Probability values <0.05 were considered statistically significant. Results: The infarct size was ~2 fold larger in PON2 deficient mice compared to WT mice (p<0.05). The threshold for opening of mitochondrial permeability transition pore (mPTP) in response to calcium overload was much lower in PON2-/- mice compared with WT mice (173±19 in PON2-/-, 250±41 in WT, nmol/mg-mitochondrial protein, p<0.05). The ROS production was ~2 fold higher in isolated cardiac mitochondria from PON2-/- mice compared with WT mice (p<0.05). ER stress protein CHOP increased significantly in PON2-/- mice compared to WT mice (normalized to WT: 1±0.05 in WT, 1.66±0.08 in PON2-/-, p<0.001). Phospho-GSK3b level was significantly downregulated in in PON2-/- mice compared to WT mice (pGSK3b/GSK3b normalized to WT: 1±0.06 in WT 0.67±0.08 in PON2-/-, p<0.05). Conclusions: PON2 regulates myocardial ischemia/reperfusion injury via inhibiting the opening of mPTP, which is associated with reduced mitochondria ROS production, deactivation of ER stress signaling CHOP and GSK3b.

scholarly journals Effects on cardiac function, remodeling and inflammation following myocardial ischemia–reperfusion injury or unreperfused myocardial infarction in hypercholesterolemic APOE*3-Leiden mice

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Niek J. Pluijmert ◽  
Cindy I. Bart ◽  
Wilhelmina H. Bax ◽  
Paul H. A. Quax ◽  
Douwe E. Atsma
Keyword(s):  
Myocardial Infarction ◽  
Clinical Trials ◽  
Myocardial Ischemia ◽  
Cardiac Function ◽  
Infarct Size ◽  
Ischemia Reperfusion ◽  
Left Ventricular ◽  
Apo E ◽  
Lv Remodeling ◽  
Myocardial Ischemia Reperfusion

Abstract Many novel therapies to treat myocardial infarction (MI), yielding promising results in animal models, nowadays failed in clinical trials for several reasons. The most used animal MI model is based on permanent ligation of the left anterior descending (LAD) coronary artery in healthy mice resulting in transmural MI, while in clinical practice reperfusion is usually accomplished by primary percutaneous coronary interventions (PCI) limiting myocardial damage and inducing myocardial ischemia–reperfusion (MI-R) injury. To evaluate a more similar murine MI model we compared MI-R injury to unreperfused MI in hypercholesterolemic apolipoprotein (APO)E*3-Leiden mice regarding effects on cardiac function, left ventricular (LV) remodeling and inflammation. Both MI-R and MI resulted in significant LV dilation and impaired cardiac function after 3 weeks. Although LV dilation, displayed by end-diastolic (EDV) and end-systolic volumes (ESV), and infarct size (IS) were restricted following MI-R compared to MI (respectively by 27.6% for EDV, 39.5% ESV, 36.0% IS), cardiac function was not preserved. LV-wall thinning was limited with non-transmural LV fibrosis in the MI-R group (66.7%). Two days after inducing myocardial ischemia, local leucocyte infiltration in the infarct area was decreased following MI-R compared to MI (36.6%), whereas systemic circulating monocytes were increased in both groups compared to sham (130.0% following MI-R and 120.0% after MI). Both MI-R and MI models against the background of a hypercholesterolemic phenotype appear validated experimental models, however reduced infarct size, restricted LV remodeling as well as a different distributed inflammatory response following MI-R resemble the contemporary clinical outcome regarding primary PCI more accurately which potentially provides better predictive value of experimental therapies in successive clinical trials.

TNF-α antagonism ameliorates myocardial ischemia-reperfusion injury in mice by upregulating adiponectin

2015 ◽  
Vol 308 (12) ◽  
pp. H1583-H1591 ◽  
Author(s):  
Chao Gao ◽  
Yi Liu ◽  
Qiujun Yu ◽  
Qiang Yang ◽  
Bing Li ◽  
...  
Keyword(s):  
Myocardial Ischemia ◽  
Cardiac Function ◽  
Infarct Size ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Globular Domain ◽  
Male Adult ◽  
Tnf Α ◽  
Myocardial Ischemia Reperfusion ◽  
Factor Α

Tumor necrosis factor-α (TNF-α) antagonism alleviates myocardial ischemia-reperfusion (MI/R) injury. However, the mechanisms by which the downstream mediators of TNF-α change after acute antagonism during MI/R remain unclear. Adiponectin (APN) exerts anti-ischemic effects, but it is downregulated during MI/R. This study was conducted to investigate whether TNF-α is responsible for the decrease of APN, and whether antagonizing TNF-α affects MI/R injury by increasing APN. Male adult wild-type (WT), APN knockout (APN KO) mice, and those with cardiac knockdowns of APN receptors via siRNA injection were subjected to 30 min of MI followed by reperfusion. The TNF-α antagonist etanercept or globular domain of APN (gAD) was injected 10 min before reperfusion. Etanercept ameliorated MI/R injury in WT mice as evidenced by improved cardiac function, and reduced infarct size and cardiomyocyte apoptosis. APN concentrations were augmented in response to etanercept, followed by an increase in AMP-activated protein kinase phosphorylation. Etanercept still increased cardiac function and reduced infarct size and apoptosis in both APN KO and APN receptors knockdown mice. However, its potential was significantly weakened in these mice compared with the WT mice. TNF-α is responsible for the decrease in APN during MI/R. The cardioprotective effects of TNF-α neutralization are partially due to the upregulation of APN. The results provide more insight into the TNF-α-mediated signaling effects during MI/R and support the need for clinical trials to validate the efficacy of acute TNF-α antagonism in the treatment of MI/R injury.

scholarly journals Cpg-ODN, a TLR9 Agonist, Aggravates Myocardial Ischemia/Reperfusion Injury by Activation of TLR9-P38 MAPK Signaling

2018 ◽  
Vol 47 (4) ◽  
pp. 1389-1398 ◽  
Author(s):  
Liang Xie ◽  
Songqing He ◽  
Na Kong ◽  
Ying Zhu ◽  
Yi Tang ◽  
...  
Keyword(s):  
Survival Rate ◽  
Myocardial Ischemia ◽  
Cardiac Function ◽  
Infarct Size ◽  
P38 Mapk ◽  
Ischemia Reperfusion ◽  
Mapk Signaling ◽  
Cpg Odn ◽  
Myocardial Ischemia Reperfusion ◽  
Tlr9 Activation

Background/Aims: Toll-like receptors (TLRs) have been implicated in myocardial ischemia/ reperfusion (I/R) injury. We examined the effect of CpG-oligodeoxynucleotide (ODN) on myocardial I/R injury. Methods: Male Sprague-Dawley rats were treated with either CpG-ODN or control ODN 1 h prior to myocardial ischemia (30 min) followed by reperfusion. Rats treated with phosphate-buffered saline (PBS) served as I/R controls (n = 8/group). Infarct size was determined by 2,3,5-triphenyltetrazolium chloride and Evans blue straining. Cardiac function was examined by echocardiography before and up to 14 days after myocardial I/R. Results: CpG-ODN administration significantly increased infarct size and reduced cardiac function and survival rate after myocardial I/R, compared to the PBS-treated I/R group. Control-ODN did not alter I/R-induced myocardial infarct size, cardiac dysfunction, and survival rate. Additionally, CpG-ODN promoted I/R-induced myocardial apoptosis and cleaved caspase-3 levels in the myocardium. CpG-ODN increased TLR9 activation and p38 phosphorylation in the myocardium. In vitro data also suggested that CpG-ODN treatment induced TLR9 activation and p38 phosphorylation. Importantly, p38 mitogen-activated protein kinase (MAPK) inhibition abolished CpG-ODN-induced cardiac injury. Conclusion: CpG-ODN, the TLR9 ligand, accelerates myocardial I/R injury. The mechanisms involve activation of the TLR9-p38 MAPK signaling pathway.

scholarly journals Novel Insight into the Role of Endoplasmic Reticulum Stress in the Pathogenesis of Myocardial Ischemia-Reperfusion Injury

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Hang Zhu ◽  
Hao Zhou
Keyword(s):  
Endoplasmic Reticulum ◽  
Myocardial Ischemia ◽  
Er Stress ◽  
Stress Responses ◽  
Molecular Mechanisms ◽  
Defense Mechanism ◽  
Heart Function ◽  
Ischemia Reperfusion ◽  
Myocardial Ischemia Reperfusion ◽  
Er Homeostasis

Impaired function of the endoplasmic reticulum (ER) is followed by evolutionarily conserved cell stress responses, which are employed by cells, including cardiomyocytes, to maintain and/or restore ER homeostasis. ER stress activates the unfolded protein response (UPR) to degrade and remove abnormal proteins from the ER lumen. Although the UPR is an intracellular defense mechanism to sustain cardiomyocyte viability and heart function, excessive activation initiates ER-dependent cardiomyocyte apoptosis. Myocardial ischemia/reperfusion (I/R) injury is a pathological process occurring during or after revascularization of ischemic myocardium. Several molecular mechanisms contribute to the pathogenesis of cardiac I/R injury. Due to the dual protective/degradative effects of ER stress on cardiomyocyte viability and function, it is of interest to understand the basic concepts, regulatory signals, and molecular processes involved in ER stress following myocardial I/R injury. In this review, therefore, we present recent findings related to the novel components of ER stress activation. The complex effects of ER stress and whether they mitigate or exacerbate myocardial I/R injury are summarized to serve as the basis for research into potential therapies for cardioprotection through control of ER homeostasis.

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