Abstract 15948: Inhibition of NF-kB Signaling Attenuates Age-related Aggravation of Myocardial Ischemia/Reperfusion Injury

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Guangming Cheng ◽  
Sheng Ye ◽  
Magdy Girgis ◽  
Lin Zhao ◽  
Xing Chen ◽  
...  
Keyword(s):  
Myocardial Ischemia ◽  
Infarct Size ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
The Elderly ◽  
Age Related ◽  
Redox Responsive ◽  
Myocardial Ischemia Reperfusion Injury ◽  
Myocardial Ischemia Reperfusion

Introduction: Emerging evidence indicates that myocardial ischemia/reperfusion (I/R) injury is more severe in aged hearts. Although nuclear factor-kappaB (NF-kB) activity increases with aging, whether this redox-responsive transcription factor plays any role in age-related worsening of I/R injury remains unknown. Hypothesis: We hypothesized that activation of myocardial NF-kB exerts deleterious effects during I/R injury in young as well as aged hearts; and that NF-kB signaling contributes to age-related worsening of myocardial I/R injury. Methods: We used transgenic mice overexpressing a mutant IkBa that prevents NF-kB activation only in the heart. Age-matched young (10-week-old) and aged (86-week-old) male non-transgenic littermates (NTg) and IkBa transgenic (Tg) mice underwent a 30-min coronary occlusion followed by 24 h of reperfusion. Following sacrifice, infarct size was measured and molecular assays were performed. Results: The infarct size was significantly smaller in young Tg mice compared with young NTg mice (Fig), indicating a deleterious role of NF-kB signaling during myocardial I/R injury even in the young. The infarct size in aged NTg hearts was greater compared with young NTg hearts, consistent with an age-related worsening of I/R injury effects. However, infarct size in aged Tg hearts was significantly smaller than aged NTg hearts, and similar to young Tg hearts, indicating that NF-kB signaling contributes toward age-related aggravation of I/R injury. Interestingly, the levels of molecular markers of senescence, such as p16, were lower in aged Tg hearts (Fig), indicating a deleterious role of NF-kB in cardiac aging and susceptibility to I/R injury. Conclusions: We conclude that inhibition of cardiac NF-kB signaling protects against age-related aggravation of acute myocardial I/R injury. These findings suggest that modulation of NF-kB signaling may be potentially used to achieve therapeutic cardioprotection in the elderly.

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.

Abstract 11928: Cardiospecific Overexpression of Carnosine Synthase Attenuates Myocardial Ischemia Reperfusion Injury

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Shahid Baba ◽  
Deqing zhang ◽  
David Hoetker ◽  
Yiru Guo ◽  
Aruni Bhatnagar
Keyword(s):  
Myocardial Ischemia ◽  
Infarct Size ◽  
Ischemia Reperfusion Injury ◽  
Membrane Lipids ◽  
Ischemia Reperfusion ◽  
Glycolytic Activity ◽  
Myocardial Ischemia Reperfusion Injury ◽  
Myocardial Ischemia Reperfusion ◽  
Underlying Mechanisms

Even though myocardial ischemia/reperfusion (I/R) remains the leading cause of death, the underlying mechanisms remain incompletely understood. Increased formation of reactive carbonyl has been shown to be a common biochemical feature of I/R injury. These carbonyls are generated from the oxidation of proteins and membrane lipids. Reactive carbonyls such as methylglyoxal are generated from increased glycolytic activity during ischemia. Previous work in our lab has shown that the endogenous dipeptide carnosine (β-alanine-histidine) quenches both protein and lipid derived carbonyls. It can also buffer changes in intracellular pH and chelate metals that catalyze ROS production. In the heart, carnosine is synthesized by the ATP grasp enzyme (ATPGD1). Hence, we examined whether overexpression of ATPGD1 could increase carnosine synthesis in the heart and attenuate I/R injury. To overexpress ATPGD1, we generated mice in which the expression of the transgene was driven by cardiospecific α-MHC promoter. Two different ATPGD1Tg mouse lines were generated, which showed 10-15 fold higher abundance of ATPGD1 protein in the heart compared with their wild-type (WT) littermates. Cardiac levels of the histidyl dipeptides anserine and carnosine were approximately 100 fold higher in the ATPGD1Tg than WT mice hearts (WT: anserine 1.8±0.3 pmoles/mg protein, carnosine 6±1 pmoles/mg protein; ATPGD1-Tg: anserine 114±15 pmoles/mg protein, carnosine 615±44 pmoles/mg protein). No changes in the levels of these dipeptides were observed in other tissues of the ATPGD1Tg mice. Echocardiographic analysis showed that ATPGD1 overexpression did not affect cardiac function. When subjected to 30 min of coronary occlusion followed by 24 h of reperfusion, the infarct size was significantly lower in ATPGD1Tg than WT mice. Infarct size as the area of risk of left ventricle was 59±3.02% in WT mice and 38±2.73% in the ATPGD1-Tg mice (p<0.05 vs WT; n=7-8), indicating that increasing carnosine levels attenuates myocardial I/R injury. These findings reveal a novel cardioprotective role of endogenous histidyl dipeptides in decreasing I/R injury and suggest that treatment with such peptides may be a potential therapy for decreasing myocardial I/R injury and its progression of heart failure.

MicroRNA-330-5p inhibits NLRP3 inflammasome-mediated myocardial ischemia-reperfusion injury by targeting TIM3

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
W Zuo ◽  
R Tian ◽  
Q Chen ◽  
L Wang ◽  
Q Gu ◽  
...  
Keyword(s):  
Myocardial Ischemia ◽  
Reperfusion Injury ◽  
Nlrp3 Inflammasome ◽  
Ischemia Reperfusion Injury ◽  
Infarct Volume ◽  
Ischemia Reperfusion ◽  
Left Ventricular ◽  
Myocardial Ischemia Reperfusion Injury ◽  
Myocardial Ischemia Reperfusion

Abstract Background Myocardial ischemia-reperfusion injury (MIRI) is one of the leading causes of human death. Nod-like receptor protein-3 (NLRP3) inflammasome signaling pathway involved in the pathogenesis of MIRI. However, the upstream regulating mechanisms of NLRP3 at molecular level remains unknown. Purpose This study investigated the role of microRNA330-5p (miR-330-5p) in NLRP3 inflammasome-mediated MIRI and the associated mechanism. Methods Mice underwent 45 min occlusion of the left anterior descending coronary artery followed by different times of reperfusion. Myocardial miR-330-5p expression was examined by quantitative polymerase chain reaction (PCR), and miR-330-5p antagomir and agomir were used to regulate miR-330-5p expression. To evaluate the role of miR-330-5p in MIRI, Evans Blue (EB)/2, 3, 5-triphenyltetrazolium chloride (TTC) staining, echocardiography, and immunoblotting were used to assess infarct volume, cardiac function, and NLRP3 inflammasome activation, respectively. Further, in vitro myocardial ischemia-reperfusion model was established in cardiomyocytes (H9C2 cell line). A luciferase binding assay was used to examine whether miR-330-5p directly bound to T-cell immunoglobulin domain and mucin domain-containing molecule-3 (TIM3). Finally, the role of miR-330-5p/TIM3 axis in regulating apoptosis and NLRP3 inflammasome formation were evaluated using flow cytometry assay and immunofluorescence staining. Results Compared to the model group, inhibiting miR-330-5p significantly aggravated MIRI resulting in increased infarct volume (58.09±6.39% vs. 37.82±8.86%, P&lt;0.01) and more severe cardiac dysfunction (left ventricular ejection fraction [LVEF] 12.77%±6.07% vs. 27.44%±4.47%, P&lt;0.01; left ventricular end-diastolic volume [LVEDV] 147.18±25.82 vs. 101.31±33.20, P&lt;0.05; left ventricular end-systolic volume [LVESV] 129.11±30.17 vs. 74.29±28.54, P&lt;0.05). Moreover, inhibiting miR-330-5p significantly increased the levels of NLRP3 inflammasome related proteins including caspase-1 (0.80±0.083 vs. 0.60±0.062, P&lt;0.05), interleukin (IL)-1β (0.87±0.053 vs. 0.79±0.083, P&lt;0.05), IL-18 (0.52±0.063 vs. 0.49±0.098, P&lt;0.05) and tissue necrosis factor (TNF)-α (1.47±0.17 vs. 1.03±0.11, P&lt;0.05). Furthermore, TIM3 was confirmed as a potential target of miR-330-5p. As predicted, suppression of TIM3 by small interfering RNA (siRNA) ameliorated the anti-miR-330-5p-mediated apoptosis of cardiomyocytes and activation of NLRP3 inflammasome signaling pathway (Figure 1). Conclusion Overall, our study indicated that miR-330-5p/TIM3 axis involved in the regulating mechanism of NLRP3 inflammasome-mediated myocardial ischemia-reperfusion injury. Figure 1 Funding Acknowledgement Type of funding source: Foundation. Main funding source(s): National Natural Science Foundation of China Grants

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