Ischemic preconditioning, insulin, and morphine all cause hexokinase redistribution

2005 ◽  
Vol 289 (1) ◽  
pp. H496-H499 ◽  
Author(s):  
Coert J. Zuurbier ◽  
Otto Eerbeek ◽  
Alfred J. Meijer
Keyword(s):  
Ischemic Preconditioning ◽  
Citrate Synthase ◽  
Mitochondrial Permeability Transition ◽  
Ischemia Reperfusion ◽  
Cell Activity ◽  
Permeability Transition ◽  
Cytosol Fraction ◽  
Whole Cell ◽  
Mitochondrial Integrity ◽  
Mitochondrial Fractions

Association of hexokinase (HK) with mitochondria preserves mitochondrial integrity and is an important mechanism by which cancer cells are protected against hypoxic conditions. Maintenance of mitochondrial integrity also figures prominently as a major characteristic of many cardioprotective manipulations. In this study, we provide evidence that cardioprotective interventions may promote HK redistribution from the cytosol to the mitochondria in the heart. Isolated Langendorff-perfused rat hearts ( n = 6/group) were subjected to normoxic perfusion (control, Con), three 5-min ischemia-reperfusion periods (ischemic preconditioning, IPC), 1 U/l insulin (Ins), or 1 μM morphine (Mor). Hearts were immediately homogenized and centrifuged to obtain whole cell, cytosolic, and mitochondrial fractions. HK, lactate dehydrogenase (LDH), and citrate synthase (CS) enzyme activities were determined. No change in LDH or CS present in the cytosol fraction relative to whole cell activity was observed with any of the cardioprotective interventions. By contrast, HK present in the cytosol fraction relative to whole cell activity decreased significantly ( P < 0.05) with all cardioprotective interventions, from 0.58 ± 0.03 (Con) to 0.46 ± 0.04 (IPC), 0.41 ± 0.01 (Ins), and 0.45 ± 0.02 (Mor). In addition, HK relative to CS activity in the mitochondrial fraction increased significantly with cardioprotection, from 0.15 ± 0.001 (Con) to 0.21 ± 0.002 (IPC), 0.18 ± 0.003 (Ins), and 0.21 ± 0.005 (Mor). Our novel data suggest that well-known cardioprotective interventions share a common end-effector mechanism of cytosolic HK translocation. Association of HK with mitochondria may promote inhibition of the mitochondrial permeability transition pore and thereby reduce cell death and apoptosis.

scholarly journals The Role of O-GlcNAcylation for Protection against Ischemia-Reperfusion Injury

2019 ◽  
Vol 20 (2) ◽  
pp. 404 ◽  
Author(s):  
Rebekka Jensen ◽  
Ioanna Andreadou ◽  
Derek Hausenloy ◽  
Hans Bøtker
Keyword(s):  
Reperfusion Injury ◽  
Ischemic Preconditioning ◽  
Mitochondrial Permeability Transition ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Permeability Transition Pore ◽  
Permeability Transition ◽  
Mechanical Conditioning ◽  
Cell Functions ◽  
Heat Shock Responses

Ischemia reperfusion injury (IR injury) associated with ischemic heart disease contributes significantly to morbidity and mortality. O-linked β-N-acetylglucosamine (O-GlcNAc) is a dynamic posttranslational modification that plays an important role in numerous biological processes, both in normal cell functions and disease. O-GlcNAc increases in response to stress. This increase mediates stress tolerance and cell survival, and is protective. Increasing O-GlcNAc is protective against IR injury. Experimental cellular and animal models, and also human studies, have demonstrated that protection against IR injury by ischemic preconditioning, and the more clinically applicable remote ischemic preconditioning, is associated with increases in O-GlcNAc levels. In this review we discuss how the principal mechanisms underlying tissue protection against IR injury and the associated immediate elevation of O-GlcNAc may involve attenuation of calcium overload, attenuation of mitochondrial permeability transition pore opening, reduction of endoplasmic reticulum stress, modification of inflammatory and heat shock responses, and interference with established cardioprotective pathways. O-GlcNAcylation seems to be an inherent adaptive cytoprotective response to IR injury that is activated by mechanical conditioning strategies.

scholarly journals Acetaminophen-mediated cardioprotection via inhibition of the mitochondrial permeability transition pore-induced apoptotic pathway

2007 ◽  
Vol 293 (6) ◽  
pp. H3348-H3355 ◽  
Author(s):  
Norell M. Hadzimichalis ◽  
Sunanda S. Baliga ◽  
Roseli Golfetti ◽  
Kathryn M. Jaques ◽  
Bonnie L. Firestein ◽  
...  
Keyword(s):  
Mitochondrial Permeability Transition Pore ◽  
Mitochondrial Permeability Transition ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Permeability Transition Pore ◽  
Permeability Transition ◽  
Low Flow ◽  
Apoptotic Pathway ◽  
Mitochondrial Permeability ◽  
Mitochondrial Fractions

Our laboratory has previously reported that acetaminophen confers functional cardioprotection following cardiac insult, including ischemia/reperfusion, hypoxia/reoxygenation, and exogenous peroxynitrite administration. In the present study, we further examined the mechanism of acetaminophen-mediated cardioprotection following ischemia/reperfusion injury. Langendorff-perfused guinea pig hearts were exposed to acute treatment with acetaminophen (0.35 mM) or vehicle beginning at 15 min of a 30-min baseline stabilization period. Low-flow global myocardial ischemia was subsequently induced for 30 min followed by 60 min of reperfusion. At the completion of reperfusion, hearts were homogenized and separated into cytosolic and mitochondrial fractions. Mitochondrial swelling and mitochondrial cytochrome c release were assessed and found to be significantly and completely reduced in acetaminophen- vs. vehicle-treated hearts following reperfusion. In a separate group of hearts, ventricular myocytes were isolated and subjected to fluorescence-activated cell sorting. Acetaminophen-treated hearts showed a significant decrease in late stage apoptotic myocytes compared with vehicle-treated hearts following injury (58 ± 1 vs. 81 ± 5%, respectively). These data, together with electron micrograph analysis, suggest that acetaminophen mediates cardioprotection, in part, via inhibition of the mitochondrial permeability transition pore and subsequent apoptotic pathway.

Stress-induced opening of the permeability transition pore in the dystrophin-deficient heart is attenuated by acute treatment with sildenafil

2011 ◽  
Vol 300 (1) ◽  
pp. H144-H153 ◽  
Author(s):  
Alexis Ascah ◽  
Maya Khairallah ◽  
Frédéric Daussin ◽  
Céline Bourcier-Lucas ◽  
Richard Godin ◽  
...  
Keyword(s):  
Mitochondrial Permeability Transition ◽  
Contractile Function ◽  
Ex Vivo ◽  
Ischemia Reperfusion ◽  
Clinical Signs ◽  
Permeability Transition Pore ◽  
Permeability Transition ◽  
Mdx Mice ◽  
Uptake Velocity ◽  
Ptp Opening

Susceptibility of cardiomyocytes to stress-induced damage has been implicated in the development of cardiomyopathy in Duchenne muscular dystrophy, a disease caused by the lack of the cytoskeletal protein dystrophin in which heart failure is frequent. However, the factors underlying the disease progression are unclear and treatments are limited. Here, we tested the hypothesis of a greater susceptibility to the opening of the mitochondrial permeability transition pore (PTP) in hearts from young dystrophic ( mdx) mice (before the development of overt cardiomyopathy) when subjected to a stress protocol and determined whether the prevention of a PTP opening is involved in the cardioprotective effect of sildenafil, which we have previously reported in mdx mice. Using the 2-deoxy-[3H]glucose method to quantify the PTP opening in ex vivo perfused hearts, we demonstrate that when compared with those of controls, the hearts from young mdx mice subjected to ischemia-reperfusion (I/R) display an excessive PTP opening as well as enhanced activation of cell death signaling, mitochondrial oxidative stress, cardiomyocyte damage, and poorer recovery of contractile function. Functional analyses in permeabilized cardiac fibers from nonischemic hearts revealed that in vitro mitochondria from mdx hearts display normal respiratory function and reactive oxygen species handling, but enhanced Ca2+ uptake velocity and premature opening of the PTP, which may predispose to I/R-induced injury. The administration of a single dose of sildenafil to mdx mice before I/R prevented excessive PTP opening and its downstream consequences and reduced tissue Ca2+ levels. Furthermore, mitochondrial Ca2+ uptake velocity was reduced following sildenafil treatment. In conclusion, beyond our documentation that an increased susceptibility to the opening of the mitochondrial PTP in the mdx heart occurs well before clinical signs of overt cardiomyopathy, our results demonstrate that sildenafil, which is already administered in other pediatric populations and is reported safe and well tolerated, provides efficient protection against this deleterious event, likely by reducing cellular Ca2+ loading and mitochondrial Ca2+ uptake.

scholarly journals Activation of the oxygen-sensing signal cascade prevents mitochondrial injury after mouse liver ischemia-reperfusion

2008 ◽  
Vol 295 (4) ◽  
pp. G823-G832 ◽  
Author(s):  
Zhi Zhong ◽  
Venkat K. Ramshesh ◽  
Hasibur Rehman ◽  
Robert T. Currin ◽  
Vijayalakshmi Sridharan ◽  
...  
Keyword(s):  
Mitochondrial Permeability Transition ◽  
Oxygen Sensing ◽  
Ischemia Reperfusion ◽  
Multiphoton Microscopy ◽  
Specific Inhibitor ◽  
Permeability Transition ◽  
Heme Oxygenase 1 ◽  
Mitochondrial Depolarization ◽  
Signal Cascade

The mitochondrial permeability transition (MPT) plays an important role in hepatocyte death caused by ischemia-reperfusion (IR). This study investigated whether activation of the cellular oxygen-sensing signal cascade by prolyl hydroxylase inhibitors (PHI) protects against the MPT after hepatic IR. Ethyl 3,4-dihyroxybenzoate (EDHB, 100 mg/kg ip), a PHI, increased mouse hepatic hypoxia-inducible factor-1α and heme oxygenase-1 (HO-1). EDHB-treated and untreated mice were subjected to 1 h of warm ischemia to ∼70% of the liver followed by reperfusion. Mitochondrial polarization, cell death, and the MPT were assessed by intravital confocal/multiphoton microscopy of rhodamine 123, propidium iodide, and calcein. EDHB largely blunted alanine aminotransferase (ALT) release and necrosis after reperfusion. In vehicle-treated mice at 2 h after reperfusion, viable cells with depolarized mitochondria were 72%, and dead cells were 2%, indicating that depolarization preceded necrosis. Mitochondrial voids excluding calcein disappeared, indicating MPT onset in vivo. NIM811, a specific inhibitor of the MPT, blocked mitochondrial depolarization after IR, further confirming that mitochondrial depolarization was due to MPT onset. EDHB decreased mitochondrial depolarization to 16% and prevented the MPT. Tin protoporphyrin (10 μmol/kg sc), an HO-1 inhibitor, partially abrogated protection by EDHB against ALT release, necrosis, and mitochondrial depolarization. In conclusion, IR causes the MPT and mitochondrial dysfunction, leading to hepatocellular death. PHI prevents MPT onset and liver damage through an effect mediated partially by HO-1.

Abstract 17188: Cryoem Analysis in Cardiac Isolated Mitochondria Reveals New Insights for CsA and mPTP Activation

Circulation ◽  
2018 ◽  
Vol 138 (Suppl_1) ◽  
Author(s):  
Jasiel O Strubbe ◽  
Jason Schrad ◽  
James F Conway ◽  
Kristin N Parent ◽  
Jason N Bazil
Keyword(s):  
Time Course ◽  
Mitochondrial Permeability Transition ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Myocardial Necrosis ◽  
Permeability Transition Pore ◽  
Permeability Transition ◽  
Granule Formation ◽  
Membrane Rupture ◽  
Mptp Opening

Excessive Ca 2+ accumulation is the main source of cardiac tissue and cell death during myocardial ischemia-reperfusion injury (IR injury) and myocardial infarction. Calcium dysregulation and overload leads to mitochondrial dysfunction, excessive reactive oxygen species (ROS) production, catastrophic energy failure, and opening of the cyclosporine A-sensitive mitochondrial permeability transition pore (mPTP). Mitochondrial Ca 2+ accumulation also results in the formation of amorphous Ca 2+ -phosphate granules localized in the mitochondrial matrix. These amorphous electron-dense granules are main components of the mitochondrial Ca 2+ sequestration and buffering system by mechanisms not yet well understood. The two aims of the present study are to test the relationship of Ca 2+ -phosphate granule size and number in cardiac mitochondria 1) exposed to a bolus calcium sufficient to elicit permeabilization and 2) whether CsA-treated mitochondria alters granule formation and size. A time course series of CryoEM images was analyzed to follow the permeabilization process. CryoEM results showed that mitochondrial incubated for longer time-courses have increased number of small granules (40 - 110 nm), swelling, membrane rupture and induction of mPTP opening. Conversely, shorter incubation time resulted in less granules per mitochondrion yet of similar size (35 - 90 nm). CsA- treated mitochondria, on the other hand, showed bigger phosphate granules (120 - 160 nm), and both lower granules per mitochondria and mPTP opening susceptibility. These results suggest a novel mechanism for CsA in which Ca 2+ -phosphate granule sizes are enhanced while maintaining fewer per mitochondrion. This effect may explain why CsA-treated mitochondria have higher calcium tolerance, delayed Ca 2+ -dependent opening of the mPTP, and protects against reperfusion-induced myocardial necrosis.

Abstract MP124: De-palmitoylation of Cysteine 202 of Cyclophilin-D by Calcium is Important for the Activation of the Permeability Transition Pore

2020 ◽  
Vol 127 (Suppl_1) ◽  
Author(s):  
Georgios Amanakis ◽  
Junhui Sun ◽  
Maria Fergusson ◽  
Chengyu Liu ◽  
Jeff D Molkentin ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Mitochondrial Permeability Transition ◽  
Ischemia Reperfusion ◽  
Permeability Transition Pore ◽  
Permeability Transition ◽  
Calcium Overload ◽  
Mitochondrial Calcium ◽  
Cyclophilin D ◽  
Perfused Heart ◽  
Knock Out

Cyclophilin-D (CypD) is a well-known regulator of the mitochondrial permeability transition pore (PTP), the main effector of cardiac ischemia/reperfusion (I/R) injury characterized by oxidative stress and calcium overload. However, the mechanism by which CypD activates PTP is poorly understood. Cysteine 202 of CypD (C202) is highly conserved across species and can undergo redox-sensitive post-translational modifications, such as S-nitrosylation and oxidation. To study the importance of C202, we developed a knock-in mouse model using CRISPR where CypD-C202 was mutated to a serine (C202S). Hearts from these mice are protected against I/R injury. We found C202 to be abundantly S-palmitoylated under baseline conditions while C202 was de-palmitoylated during ischemia in WT hearts. To further investigate the mechanism of de-palmitoylation during ischemia, we considered the increase of matrix calcium, oxidative stress and uncoupling of ATP synthesis from the electron transport chain. We tested the effects of these conditions on the palmitoylation of CypD in isolated cardiac mitochondria. The palmitoylation of CypD was assessed using a resin-assisted capture (Acyl-RAC). We report that oxidative stress (phenylarsenide) and uncoupling (CCCP) had no effect on CypD palmitoylation (p>0.05, n=3 and n=7 respectively). However, calcium overload led to de-palmitoylation of CypD to the level observed at the end ischemia (1±0.10 vs 0.63±0.09, p=0.012, n=9). To further test the hypothesis that calcium regulates S-palmitoylation of CypD we measured S-palmitoylation of CypD in non-perfused heart lysates from global germline mitochondrial calcium uniporter knock-out mice (MCU-KO), which have reduced mitochondrial calcium and we found an increase in S-palmitoylation of CypD (WT 1±0.04 vs MCU-KO 1.603±0.11, p<0.001, n=6). The data are consistent with the hypothesis that C202 is important for the CypD mediated activation of PTP. Ischemia leads to increased matrix calcium which in turn promotes the de-palmitoylation of CypD on C202. The now free C202 can further be oxidized during reperfusion leading to the activation of PTP. Thus, S-palmitoylation and oxidation of CypD-C202 possibly target CypD to the PTP, making them potent regulators of cardiac I/R injury.

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