scholarly journals Does p53 Inhibition Suppress Myocardial Ischemia–Reperfusion Injury?

2018 ◽  
Vol 23 (4) ◽  
pp. 350-357 ◽  
Author(s):  
Toshiyuki Yano ◽  
Koki Abe ◽  
Masaya Tanno ◽  
Takayuki Miki ◽  
Atsushi Kuno ◽  
...  
Keyword(s):  
Myocardial Ischemia ◽  
Mitochondrial Permeability Transition ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Late Phase ◽  
Permeability Transition Pore ◽  
Permeability Transition ◽  
Rate Pressure Product ◽  
Myocardial Ischemia Reperfusion

p53 is well known as a regulator of apoptosis and autophagy. In addition, a recent study showed that p53 is a modulator of the opening of the mitochondrial permeability transition pore (mPTP), a trigger event of necrosis, but the role of p53 in necrosis induced by myocardial ischemia–reperfusion (I/R) remains unclear. The aim of this study was to determine the role of p53 in acute myocardial I/R injury in perfused mouse hearts. In male C57BL6 mice between 12 and 15 weeks of age, 2 types of p53 inhibitors were used to suppress p53 function during I/R: pifithrin-α, an inhibitor of transcriptional functions of p53, and pifithrin-μ, an inhibitor of p53 translocation from the cytosol to mitochondria. Neither infusion of these inhibitors before ischemia nor infusion for the first 30-minute period of reperfusion reduced infarct size after 20-minute ischemia/120-minute reperfusion. Infarct sizes were similar in p53 heterozygous knockout mice (p53+/−) and wild-type mice (WT), but recovery of rate pressure product (RRP) 120 minutes after reperfusion was higher in p53+/− than in WT. The protein expression of p53 in WT was negligible under baseline conditions, during ischemia, and at 10 minutes after the start of reperfusion, but it became detectable at 120 minutes after reperfusion. In conclusion, upregulation of p53 during the late phase of reperfusion plays a significant role in contractile dysfunction after reperfusion, although p53 is not involved in cardiomyocyte necrosis during ischemia or in the early phase of reperfusion.

scholarly journals Mitochondrial bioenergetics and cardiolipin alterations in myocardial ischemia-reperfusion injury: implications for pharmacological cardioprotection

2018 ◽  
Vol 315 (5) ◽  
pp. H1341-H1352 ◽  
Author(s):  
Giuseppe Paradies ◽  
Valeria Paradies ◽  
Francesca Maria Ruggiero ◽  
Giuseppe Petrosillo
Keyword(s):  
Myocardial Ischemia ◽  
Mitochondrial Dysfunction ◽  
Mitochondrial Permeability Transition ◽  
Ischemia Reperfusion Injury ◽  
Mitochondrial Dynamics ◽  
Ischemia Reperfusion ◽  
Permeability Transition Pore ◽  
Permeability Transition ◽  
Mitochondrial Morphology ◽  
Myocardial Ischemia Reperfusion

Mitochondrial dysfunction plays a central role in myocardial ischemia-reperfusion (I/R) injury. Increased reactive oxygen species production, impaired electron transport chain activity, aberrant mitochondrial dynamics, Ca2+ overload, and opening of the mitochondrial permeability transition pore have been proposed as major contributory factors to mitochondrial dysfunction during myocardial I/R injury. Cardiolipin (CL), a mitochondria-specific phospholipid, plays a pivotal role in multiple mitochondrial bioenergetic processes, including respiration and energy conversion, in mitochondrial morphology and dynamics as well as in several steps of the apoptotic process. Changes in CL levels, species composition, and degree of oxidation may have deleterious consequences for mitochondrial function with important implications in a variety of pathophysiological conditions, including myocardial I/R injury. In this review, we focus on the role played by CL alterations in mitochondrial dysfunction in myocardial I/R injury. Pharmacological strategies to prevent myocardial injury during I/R targeting mitochondrial CL are also examined.

scholarly journals Mitochondria “THE” target of myocardial conditioning

2018 ◽  
Vol 315 (5) ◽  
pp. H1215-H1231 ◽  
Author(s):  
Kerstin Boengler ◽  
Günter Lochnit ◽  
Rainer Schulz
Keyword(s):  
Reperfusion Injury ◽  
Mitochondrial Function ◽  
Mitochondrial Permeability Transition ◽  
Ischemia Reperfusion Injury ◽  
Mitochondrial Dynamics ◽  
Ischemia Reperfusion ◽  
Permeability Transition Pore ◽  
Permeability Transition ◽  
Myocardial Ischemia Reperfusion Injury ◽  
Myocardial Ischemia Reperfusion

Several interventions, such as ischemic preconditioning, remote pre/perconditioning, or postconditioning, are known to decrease lethal myocardial ischemia-reperfusion injury. While several signal transduction pathways become activated by such maneuvers, they all have a common end point, namely, the mitochondria. These organelles represent an essential target of the cardioprotective strategies, and the preservation of mitochondrial function is central for the reduction of ischemia-reperfusion injury. In the present review, we address the role of mitochondria in the different conditioning strategies; in particular, we focus on alterations of mitochondrial function in terms of energy production, formation of reactive oxygen species, opening of the mitochondrial permeability transition pore, and mitochondrial dynamics induced by ischemia-reperfusion.

Abstract 14997: Zn2+ and mPTP Mediate ERS Inhibition-induced Cardioprotection Against Ischemia/Reperfusion Injury

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Jinkun Xi ◽  
Yonggui He ◽  
Shuo Fei ◽  
Huan Zheng ◽  
Zhelong Xu
Keyword(s):  
Endoplasmic Reticulum ◽  
Reperfusion Injury ◽  
Mitochondrial Permeability Transition ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Permeability Transition Pore ◽  
Permeability Transition ◽  
Mptp Opening ◽  
Role Of Zn

While the role of endoplasmic reticulum stress (ERS) in myocardial ischemia/reperfusion (I/R) injury has been extensively investigated, the precise mechanism by which inhibition of ERS induces cardioprotection remains unclear. We aimed to explore the mechanism of ERS inhibition-induced cardioprotection against I/R injury, focusing on the role of Zn 2+ and the mitochondrial permeability transition pore (mPTP). Exposure of H9c2 cells to 800 μM H 2 O 2 for 20 min increased GRP78 and GRP94 expressions (296.2 ± 41.0 and 150.6 ± 13.5 %, respectively), suggesting that H 2 O 2 can induce ERS. Cells treated with H 2 O 2 showed a significant decrease (40.6 ± 7.4 %) in TMRE fluorescence compared to the normal group (92.6 ± 0.1 %), indicating that H 2 O 2 can induce the mPTP opening. In contrast, ERS inhibitor TUDCA (30 μM) prevented the loss of TMRE fluorescence (77.8 ± 6.8 %), implying that inhibition of ERS can prevent the mPTP opening. This effect of TUDCA was blocked by zinc chelator TPEN (37.7 ± 13.0 %), indicating a role of Zn 2+ in the action of TUDCA on the mPTP opening. In support, TUDCA increased intracellular free zinc, as indicated by a marked increase in Newport Green DCF fluorescence intensity. In isolated rat hearts, GRP78 expression was not increased during ischemia but was increased upon reperfusion (1.3, 1.5, 1.9, and 1.6-fold increases at 10, 30, 60, and 120 min of reperfusion). Hearts treated with TUDCA showed a significant reduction of GRP78 expression 30 and 60 min after the onset of reperfusion, an effect that was reversed by TPEN. The immunofluorescence study also showed that the effect of TUDCA on GRP78 expression was reversed by TPEN. TUDCA reduced infarct size, and this was reversed by the mPTP opener atractyloside, indicating that ERS inhibition may protect the heart by modulating the mPTP opening. Experiments with transmission electron microscopy and hematoxylin-eosin staining revealed that TUDCA prevented endoplasmic reticulum and mitochondrial damages at reperfusion, which was blocked by TPEN. In conclusion, reperfusion but not ischemia initiates ERS and inhibition of ERS protects the heart from reperfusion injury through prevention of the mPTP opening. Increased intracellular free Zn 2+ accounts for the cardioprotective effect of ERS inhibition.

Sign in / Sign up

Export Citation Format

Share Document