scholarly journals The Protective Effect of Fasudil on the Structure and Function of Cardiac Mitochondria from Rats with Type 2 Diabetes Induced by Streptozotocin with a High-Fat Diet Is Mediated by the Attenuation of Oxidative Stress

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Rong Guo ◽  
Baoxin Liu ◽  
Shunping Zhou ◽  
Buchun Zhang ◽  
Yawei Xu
Keyword(s):  
Oxidative Stress ◽  
High Fat Diet ◽  
Mitochondrial Permeability Transition ◽  
Myocardial Dysfunction ◽  
Permeability Transition Pore ◽  
Permeability Transition ◽  
Saline Control ◽  
Cardiac Mitochondria ◽  
High Fat ◽  
Rock Inhibitor

Dysfunction of cardiac mitochondria appears to play a substantial role in cardiomyopathy or myocardial dysfunction and is a promising therapeutic target for many cardiovascular diseases. We investigated the effect of the Rho/Rho-associated protein kinase (ROCK) inhibitor fasudil on cardiac mitochondria from rats in which diabetes was induced by a combination of streptozotocin (STZ) and a sustained high-fat diet. Eight weeks after diabetes was induced by a single intraperitoneal injection of 50 mg/kg STZ followed by a sustained high-fat diet, either fasudil (5 mg/kg bid) or equivalent volumes of saline (control) were administered over four weeks. Fasudil significantly protected against the histopathologic changes of cardiac mitochondria in diabetic rats. Fasudil significantly reduced the abundances of the Rho A, ROCK 1, and ROCK 2 proteins, restored the activities of succinate dehydrogenase (SDH) and monoamine oxidase (MAO) in cardiac mitochondria, inhibited the opening of the mitochondrial permeability transition pore, and decreased the total antioxidant capacity, as well as levels of malonyldialdehyde, hydroxy radical, reduced glutathione, and superoxide dismutase in heart. Fasudil improved the structures of cardiac mitochondria and increased both SDH and MAO activities in cardiac mitochondria. These beneficial effects may be associated with the attenuation of oxidative stress caused by fasudil treatment.

Abstract 305: Nebivolol Confers Mitochondria-Targeted Cardioprotection in Isoproterenol-Induced Acute Stressor State

2012 ◽  
Vol 111 (suppl_1) ◽  
Author(s):  
Sumeet S Vaikunth ◽  
Karl T Weber ◽  
Syamal K Bhattacharya
Keyword(s):  
Oxidative Stress ◽  
Cardiac Tissue ◽  
Mitochondrial Permeability Transition ◽  
Therapeutic Potential ◽  
Permeability Transition Pore ◽  
Permeability Transition ◽  
Antioxidant Defenses ◽  
Sprague Dawley ◽  
Acute Stressor ◽  
And Oxidative Stress

Introduction: Isoproterenol-induced acute stressor state simulates injury from burns or trauma, and results in Ca 2+ overloading and oxidative stress in diverse tissues, including cardiac myocytes and their subsarcolemmal mitochondria (SSM), overwhelming endogenous Zn 2+ -based antioxidant defenses. We hypothesized that pretreatment with nebivolol (Nebi), having dual beta-1 antagonistic and novel beta-3 receptor agonistic properties, would prevent Ca 2+ overloading and oxidative stress and upregulate Zn 2+ -based antioxidant defenses, thus enhancing its overall cardioprotective potential in acute stressor state. Methods: Eight-week-old male Sprague-Dawley rats received a single subcutaneous dose of isoproterenol (1 mg/kg) and compared to those treated with Nebi (10 mg/kg by gavage) for 10 days prior to isoproterenol. SSM were harvested from cardiac tissue at sacrifice. Total Ca 2+ , Zn 2+ and 8-isoprostane levels in tissue, and mitochondrial permeability transition pore (mPTP) opening, free [Ca 2+ ] m and H 2 O 2 production in SSM were monitored. Untreated, age-/sex-matched rats served as controls; each group had six rats and data shown as mean±SEM. Results: Compared to controls, isoproterenol rats revealed: (1) Significantly (*p<0.05) increased cardiac tissue Ca 2+ (8.2±0.8 vs. 13.7±1.0*, nEq/mg fat-free dry tissue (FFDT)), which was abrogated ( # p<0.05) by Nebi (8.9±0.4 # ); (2) Reduced cardiac Zn 2+ (82.8±2.4 vs. 78.5±1.0*, ng/mg FFDT), but restored by Nebi (82.4±0.6 # ); (3) Two-fold rise in cardiac 8-isoprostane (111.4±13.7 vs. 232.1±17.2*, pmoles/mg protein), and negated by Nebi (122.3+14.5 # ); (4) Greater opening propensity for mPTP that diminished by Nebi; (5) Elevated [Ca 2+ ] m (88.8±2.5 vs. 161.5±1.0*, nM), but normalized by Nebi (93.3±2.7 # ); and (6) Increased H 2 O 2 production by SSM (97.4±5.3 vs. 142.8±7.0*, pmoles/mg protein/min), and nullified by Nebi (106.8±9.0 # ). Conclusions : Cardioprotection conferred by Nebi, a unique beta-blocker, prevented Ca 2+ overloading and oxidative stress in cardiac tissue and SSM, while simultaneously augmenting antioxidant capacity and promoting mPTP stability. Therapeutic potential of Nebi in patients with acute stressor states remains a provocative possibility that deserves to be explored.

Chronic Tempol treatment restores pharmacological preconditioning in the senescent rat heart

2013 ◽  
Vol 304 (5) ◽  
pp. H649-H659 ◽  
Author(s):  
Jiang Zhu ◽  
Mario J. Rebecchi ◽  
Qiang Wang ◽  
Peter S. A. Glass ◽  
Peter R. Brink ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Mitochondrial Permeability Transition Pore ◽  
Mitochondrial Permeability Transition ◽  
Permeability Transition Pore ◽  
Permeability Transition ◽  
Cyclophilin D ◽  
Mitochondrial Permeability ◽  
Anesthetic Preconditioning ◽  
Permeability Transition Pore Opening ◽  
Pore Opening

Cardioprotective effects of anesthetic preconditioning and cyclosporine A (CsA) are lost with aging. To extend our previous work and address a possible mechanism underlying age-related differences, we investigated the role of oxidative stress in the aging heart by treating senescent animals with the oxygen free radical scavenger Tempol. Old male Fischer 344 rats (22–24 mo) were randomly assigned to control or Tempol treatment groups for 2 or 4 wk (T×2wk and T×4wk, respectively). Rats received isoflurane 30 min before ischemia-reperfusion injury or CsA just before reperfusion. Myocardial infarction sizes were significantly reduced by isoflurane or CsA in the aged rats treated with Tempol (T×4wk) compared with old control rats. In other experiments, young (4–6 mo) and old rats underwent either chronic Tempol or vehicle treatment, and the levels of myocardial protein oxidative damage, antioxidant enzymes, mitochondrial Ca2+ uptake, cyclophilin D protein, and mitochondrial permeability transition pore opening times were measured. T×4wk significantly increased MnSOD enzyme activity, GSH-to-GSSH ratios, MnSOD protein level, mitochondrial Ca2+ uptake capacity, reduced protein nitrotyrosine levels, and normalized cyclophilin D protein expression in the aged rat heart. T×4wk also significantly prolonged mitochondrial permeability transition pore opening times induced by reactive oxygen species in old cardiomyocytes. Our studies demonstrate that 4 wk of Tempol pretreatment restores anesthetic preconditioning and cardioprotection by CsA in the old rat and that this is associated with decreased oxidative stress and improved mitochondrial function. Our results point to a new protective strategy for the ischemic myocardium in the high-risk older population.

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.

scholarly journals Catalase-dependent H2O2consumption by cardiac mitochondria and redox-mediated loss in insulin signaling

2016 ◽  
Vol 311 (5) ◽  
pp. H1091-H1096 ◽  
Author(s):  
Paul M. Rindler ◽  
Angela Cacciola ◽  
Michael Kinter ◽  
Luke I. Szweda
Keyword(s):  
Oxidative Stress ◽  
Glutathione Peroxidase ◽  
Binding Affinity ◽  
Insulin Signaling ◽  
Dietary Fat ◽  
High Fat Diet ◽  
Cardiac Mitochondria ◽  
High Fat ◽  
Akt Phosphorylation ◽  
Selective Increase

We have recently demonstrated that catalase content in mouse cardiac mitochondria is selectively elevated in response to high dietary fat, a nutritional state associated with oxidative stress and loss in insulin signaling. Catalase and various isoforms of glutathione peroxidase and peroxiredoxin each catalyze the consumption of H2O2. Catalase, located primarily within peroxisomes and to a lesser extent mitochondria, has a low binding affinity for H2O2relative to glutathione peroxidase and peroxiredoxin. As such, the contribution of catalase to mitochondrial H2O2consumption is not well understood. In the current study, using highly purified cardiac mitochondria challenged with micromolar concentrations of H2O2, we found that catalase contributes significantly to mitochondrial H2O2consumption. In addition, catalase is solely responsible for removal of H2O2in nonrespiring or structurally disrupted mitochondria. Finally, in mice fed a high-fat diet, mitochondrial-derived H2O2is responsible for diminished insulin signaling in the heart as evidenced by reduced insulin-stimulated Akt phosphorylation. While elevated mitochondrial catalase content (∼50%) enhanced the capacity of mitochondria to consume H2O2in response to high dietary fat, the selective increase in catalase did not prevent H2O2-induced loss in cardiac insulin signaling. Taken together, our results indicate that mitochondrial catalase likely functions to preclude the formation of high levels of H2O2without perturbing redox-dependent signaling.

scholarly journals The P66Shc/Mitochondrial Permeability Transition Pore Pathway Determines Neurodegeneration

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Costanza Savino ◽  
PierGiuseppe Pelicci ◽  
Marco Giorgio
Keyword(s):  
Oxidative Stress ◽  
Knockout Mice ◽  
Mitochondrial Permeability Transition ◽  
Neuronal Damage ◽  
Permeability Transition Pore ◽  
Permeability Transition ◽  
Mitochondrial Swelling ◽  
Cyclophilin D ◽  
Knock Out ◽  
Mitochondrial Permeability

Mitochondrial-mediated oxidative stress and apoptosis play a crucial role in neurodegenerative disease and aging. Both mitochondrial permeability transition (PT) and swelling of mitochondria have been involved in neurodegeneration. Indeed, knockout mice for cyclophilin-D (Cyc-D), a key regulatory component of the PT pore (PTP) that triggers mitochondrial swelling, resulted to be protected in preclinical models of multiple sclerosis (MS), Parkinson’s disease (PD), and amyotrophic lateral sclerosis (ALS). However, how neuronal stress is transduced into mitochondrial oxidative stress and swelling is unclear. Recently, the aging determinant p66Shc that generates H2O2reacting with cytochrome c and induces oxidation of PTP and mitochondrial swelling was found to be involved in MS and ALS. To investigate the role of p66Shc/PTP pathway in neurodegeneration, we performed experimental autoimmune encephalomyelitis (EAE) experiments in p66Shc knockout mice (p66Shc−/−), knock out mice for cyclophilin-D (Cyc-D−/−), and p66Shc Cyc-D double knock out (p66Shc/Cyc-D−/−) mice. Results confirm that deletion of p66Shc protects from EAE without affecting immune response, whereas it is not epistatic to the Cyc-D mutation. These findings demonstrate that p66Shc contributes to EAE induced neuronal damage most likely through the opening of PTP suggesting that p66Shc/PTP pathway transduces neurodegenerative stresses.

scholarly journals Developmental Changes of the Sensitivity of Cardiac and Liver Mitochondrial Permeability Transition Pore to Calcium Load and Oxidative Stress

2012 ◽  
pp. S165-S172 ◽  
Author(s):  
Z. DRAHOTA ◽  
M. MILEROVÁ ◽  
R. ENDLICHER ◽  
D. RYCHTRMOC ◽  
Z. ČERVINKOVÁ ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Mammalian Cells ◽  
Permeability Transition Pore ◽  
Permeability Transition ◽  
Liver Mitochondria ◽  
Heart Mitochondria ◽  
Lower Sensitivity ◽  
Cardiac Mitochondria ◽  
Calcium Load ◽  
And Oxidative Stress

Opening of the mitochondrial membrane permeability transition pore (MPTP) is an important factor in the activation of apoptotic and necrotic processes in mammalian cells. In a previous paper we have shown that cardiac mitochondria from neonatal rats are more resistant to calcium load than mitochondria from adult animals. In this study we have analyzed the ontogenetic development of this parameter both in heart and in liver mitochondria. We found that the high resistance of heart mitochondria decreases from day 14 to adulthood. On the other hand, we did not observe a similar age-dependent sensitivity in liver mitochondria, particularly in the neonatal period. Some significant but relatively smaller increase could be observed only after day 30. When compared with liver mitochondria cardiac mitochondria were more resistant also to the peroxide activating effect on calcium-induced mitochondrial swelling. These data thus indicate that the MPTP of heart mitochondria is better protected against damaging effects of the calcium load and oxidative stress. We can only speculate that the lower sensitivity to calcium-induced swelling may be related to the higher ischemic tolerance of the neonatal heart.

scholarly journals Schisandrin B Antagonizes Cardiotoxicity Induced by Pirarubicin by Inhibiting Mitochondrial Permeability Transition Pore (mPTP) Opening and Decreasing Cardiomyocyte Apoptosis

2021 ◽  
Vol 12 ◽  
Author(s):  
Hongwei Shi ◽  
Heng Tang ◽  
Wen Ai ◽  
Qingfu Zeng ◽  
Hong Yang ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Mitochondrial Function ◽  
Defense Mechanism ◽  
Mitochondrial Permeability Transition ◽  
Permeability Transition Pore ◽  
Permeability Transition ◽  
Mitochondrial Swelling ◽  
Schisandrin B ◽  
Mptp Opening ◽  
H9c2 Cardiomyocytes

Objective: Pirarubicin (THP), one of the anthracycline anticancer drugs, is widely used in the treatment of various cancers, but its cardiotoxicity cannot be ignored. Schisandrin B (SchB) has the ability to upregulate cellular antioxidant defense mechanism and promote mitochondrial function and antioxidant status. However, it has not been reported whether it can resist THP-induced cardiotoxicity. The aim of this study was to investigate the effect of SchB on THP cardiotoxicity and its mechanism.Methods: The rat model of cardiotoxicity induced by THP was established, and SchB treatment was performed at the same time. The changes of ECG, cardiac coefficient, and echocardiogram were observed. The changes of myocardial tissue morphology were observed by H&amp;E staining. Apoptosis was detected by TUNEL. The levels of LDH, BNP, CK-MB, cTnT, SOD, and MDA in serum were measured to observe the heart damage and oxidative stress state of rats. The expression of cleaved-caspase 9, pro/cleaved-caspase 3, Bcl-2/Bax, and cytosol and mitochondrial Cyt C and Bax was evaluated by western blot. H9c2 cardiomyocytes were cocultured with THP, SchB, and mPTP inhibitor CsA to detect the production of ROS and verify the above signaling pathways. The opening of mPTP and mitochondrial swelling were detected by mPTP kit and purified mitochondrial swelling kit.Results: After 8 weeks, a series of cardiotoxicity manifestations were observed in THP rats. These adverse effects can be effectively alleviated by SchB treatment. Further studies showed that SchB had strong antioxidant and antiapoptotic abilities in THP cardiotoxicity.Conclusion: SchB has an obvious protective effect on THP-induced cardiotoxicity. The mechanism may be closely related to the protection of mitochondrial function, inhibition of mPTP opening, and alleviation of oxidative stress and apoptosis of cardiomyocytes.

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