scholarly journals Cyclosporin A Increases Mitochondrial Buffering of Calcium: An Additional Mechanism in Delaying Mitochondrial Permeability Transition Pore Opening

Cells ◽  
2019 ◽  
Vol 8 (9) ◽  
pp. 1052 ◽  
Author(s):  
Jyotsna Mishra ◽  
Ariea J. Davani ◽  
Gayathri K. Natarajan ◽  
Wai-Meng Kwok ◽  
David F. Stowe ◽  
...  
Keyword(s):  
Cyclosporin A ◽  
Mitochondrial Permeability Transition ◽  
Permeability Transition Pore ◽  
Extended Period ◽  
Permeability Transition ◽  
Cyclophilin D ◽  
Mptp Opening ◽  
Permeability Transition Pore Opening ◽  
Pore Opening ◽  
Matrix Free

Regulation of mitochondrial free Ca2+ is critically important for cellular homeostasis. An increase in mitochondrial matrix free Ca2+ concentration ([Ca2+]m) predisposes mitochondria to opening of the permeability transition pore (mPTP). Opening of the pore can be delayed by cyclosporin A (CsA), possibly by inhibiting cyclophilin D (Cyp D), a key regulator of mPTP. Here, we report on a novel mechanism by which CsA delays mPTP opening by enhanced sequestration of matrix free Ca2+. Cardiac-isolated mitochondria were challenged with repetitive CaCl2 boluses under Na+-free buffer conditions with and without CsA. CsA significantly delayed mPTP opening primarily by promoting matrix Ca2+ sequestration, leading to sustained basal [Ca2+]m levels for an extended period. The preservation of basal [Ca2+]m during the CaCl2 pulse challenge was associated with normalized NADH, matrix pH (pHm), and mitochondrial membrane potential (ΔΨm). Notably, we found that in PO43− (Pi)-free buffer condition, the CsA-mediated buffering of [Ca2+]m was abrogated, and mitochondrial bioenergetics variables were concurrently compromised. In the presence of CsA, addition of Pi just before pore opening in the Pi-depleted condition reinstated the Ca2+ buffering system and rescued mitochondria from mPTP opening. This study shows that CsA promotes Pi-dependent mitochondrial Ca2+ sequestration to delay mPTP opening and, concomitantly, maintains mitochondrial function.

scholarly journals SPG7 targets the m-AAA protease complex to process MCU for uniporter assembly, Ca2+ influx, and regulation of mitochondrial permeability transition pore opening

2019 ◽  
Vol 294 (28) ◽  
pp. 10807-10818 ◽  
Author(s):  
Stephen Hurst ◽  
Ariele Baggett ◽  
Gyorgy Csordas ◽  
Shey-Shing Sheu
Keyword(s):  
Mitochondrial Permeability Transition Pore ◽  
Mitochondrial Permeability Transition ◽  
Permeability Transition Pore ◽  
Permeability Transition ◽  
Cyclophilin D ◽  
Spastic Paraplegia ◽  
Mitochondrial Permeability ◽  
Mptp Opening ◽  
Permeability Transition Pore Opening ◽  
Pore Opening

The mitochondrial matrix ATPase associated with diverse cellular activities (m-AAA) protease spastic paraplegia 7 (SPG7) has been recently implicated as either a negative or positive regulatory component of the mitochondrial permeability transition pore (mPTP) by two research groups. To address this controversy, we investigated possible mechanisms that explain the discrepancies between these two studies. We found that loss of the SPG7 gene increased resistance to Ca2+-induced mPTP opening. However, this occurs independently of cyclophilin D (cyclosporine A insensitive) rather it is through decreased mitochondrial Ca2+ concentrations and subsequent adaptations mediated by impaired formation of functional mitochondrial Ca2+ uniporter complexes. We found that SPG7 directs the m-AAA complex to favor association with the mitochondrial Ca2+ uniporter (MCU) and MCU processing regulates higher order MCU-complex formation. The results suggest that SPG7 does not constitute a core component of the mPTP but can modulate mPTP through regulation of the basal mitochondrial Ca2+ concentration.

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.

scholarly journals Divergent Effects of Cyclophilin-D Inhibition on the Female Rat Heart: Acute Versus Chronic Post-Myocardial Infarction

2018 ◽  
Vol 50 (1) ◽  
pp. 288-303 ◽  
Author(s):  
Rebecca M. Parodi-Rullán ◽  
Jadira Soto-Prado ◽  
Jesús Vega-Lugo ◽  
Xavier Chapa-Dubocq ◽  
Sara I. Díaz-Cordero ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Mitochondrial Permeability Transition Pore ◽  
Mitochondrial Permeability Transition ◽  
Permeability Transition Pore ◽  
Permeability Transition ◽  
Cyclophilin D ◽  
Sanglifehrin A ◽  
Permeability Transition Pore Opening ◽  
Pore Opening ◽  
Cardioprotective Effects

Background/Aims: The mitochondrial permeability transition pore opening plays a critical role in the pathogenesis of myocardial infarction. Inhibition of cyclophilin-D (CyP-D), a key regulator of the mitochondrial permeability transition pore, has been shown to exert cardioprotective effects against ischemia-reperfusion injury on various animal models, mostly in males. However, failure of recent clinical trials requires a detailed elucidation of the cardioprotective efficacy of CyP-D inhibition. The aim of this study was to examine whether cardioprotective effects of sanglifehrin A, a potent inhibitor of CyP-D, on post-infarcted hearts depends on reperfusion. Methods: Acute or chronic myocardial infarction was induced by coronary artery ligation with/without subsequent reperfusion for 2 and 28 days in female Sprague-Dawley rats. Cardiac function was estimated by echocardiography. Oxygen consumption rates, ROS production, permeability transition pore opening, protein carbonylation and respiratory supercomplexes were analyzed in isolated cardiac mitochondria. Results: Sanglifehrin A significantly improved cardiac function of reperfused hearts at 2 days but failed to protect after 28 days. No protection was observed in non-reperfused post-infarcted hearts. The respiratory control index of mitochondria was significantly reduced in reperfused infarcted hearts at 2-days with no effect at 28-days post-infarction on reperfused and non-reperfused hearts. Likewise, only a minor increase in reactive oxygen species production was observed at 2-days in non-reperfused post-infarcted hearts. Conclusion: This study demonstrates that CyP-D inhibition exerts cardioprotective effects in reperfused but not in non-reperfused infarcted hearts of female rats, and the effects are observed only during acute post-infarction injury.

Cardioprotective Effect of Hydroxysafflor Yellow A via the Cardiac Permeability Transition Pore

Planta Medica ◽  
2017 ◽  
Vol 84 (08) ◽  
pp. 507-518 ◽  
Author(s):  
Gavin Huber ◽  
Sydney Priest ◽  
Timothy Geisbuhler
Keyword(s):  
Cyclosporin A ◽  
Cardiac Myocytes ◽  
Mitochondrial Permeability Transition Pore ◽  
Mitochondrial Permeability Transition ◽  
Permeability Transition Pore ◽  
Permeability Transition ◽  
Hydroxysafflor Yellow A ◽  
Mitochondrial Permeability ◽  
Permeability Transition Pore Opening ◽  
Pore Opening

AbstractMyocardial ischemia damages cardiac myocytes in part via opening of the mitochondrial permeability transition pore. Preventing this poreʼs opening is therefore a useful therapeutic goal in treating cardiovascular disease. Hydroxysafflor yellow A has been proposed as a nontoxic alternative to other agents that modulate mitochondrial permeability transition pore opening. In this study, we proposed that hydroxysafflor yellow A prevents mitochondrial permeability transition pore formation in anoxic cardiac myocytes, and thus protects the cell from damage seen during reoxygenation of the cardiac myocytes. Experiments with hydroxysafflor yellow A transport in aerobic myocytes show that roughly 50% of the extracellular dye concentration crosses the cell membrane in a 2-h incubation. In our anoxia/reoxygenation protocol, hydroxysafflor yellow A modulated both the reduction of viability and the loss of rod-shaped cells that attend anoxia and reoxygenation. Hydroxysafflor yellow Aʼs protective effect was similar to that of cyclosporin A, an agent known to inhibit mitochondrial permeability transition pore opening. In additional experiments, plated myocytes were loaded with calcein/MitoTracker Red, then examined for intracellular dye distribution/morphology after anoxia/reoxygenation. Hydroxysafflor yellow A-containing cells showed a cardioprotective pattern similar to that of cyclosporin A (an agent known to close the mitochondrial permeability transition pore). We conclude that hydroxysafflor yellow A can enter the cardiac myocyte and is able to modulate anoxia/reoxygenation-induced damage by interacting with the mitochondrial permeability transition pore.

Acute exercise protects against calcium-induced cardiac mitochondrial permeability transition pore opening in doxorubicin-treated rats

2010 ◽  
Vol 120 (1) ◽  
pp. 37-49 ◽  
Author(s):  
António Ascensão ◽  
José Lumini-Oliveira ◽  
Nuno G. Machado ◽  
Rita M. Ferreira ◽  
Inês O. Gonçalves ◽  
...  
Keyword(s):  
Mitochondrial Function ◽  
Acute Exercise ◽  
Mitochondrial Permeability Transition Pore ◽  
Mitochondrial Permeability Transition ◽  
Permeability Transition Pore ◽  
Exercise Bout ◽  
Permeability Transition ◽  
Mptp Opening ◽  
Permeability Transition Pore Opening ◽  
Pore Opening

The use of DOX (doxorubicin), an antibiotic used in oncological treatments, is limited by a dose-related cardiotoxicity against which acute exercise is protective. However, the mitochondrial-related mechanisms of this protection remain unknown. Therefore the present study aimed to determine the effects of an acute endurance exercise bout performed 24 h before DOX treatment on heart and liver mitochondrial function. A total of 20 adult male Wistar rats were divided into groups as follows: non-exercised with saline (NE+SAL), non-exercised DOX-treated (NE+DOX), exercised with saline (EX+SAL) and exercised DOX-treated (EX+DOX). The animals performed a 60 min exercise bout on a treadmill or remained sedentary 24 h before receiving either a DOX bolus (20 mg/kg of body weight) or saline. Heart and liver mitochondrial function [oxygen consumption, membrane potential (ΔΨ) and cyclosporin-A-sensitive calcium-induced MPTP (mitochondrial permeability transition pore) opening] were evaluated. The activities of the respiratory complex, Mn-SOD (superoxide dismutase), caspases 3 and 9, as well as the levels of ANT (adenine nucleotide translocase), VDAC (voltage-dependent anion channel), CypD (cyclophilin D), Bax and Bcl-2, were measured. Acute exercise prevented the decreased cardiac mitochondrial function (state 3, phosphorylative lag-phase; maximal ΔΨ generated both with complex I- and II-linked substrates and calcium-induced MPTP opening) induced by DOX treatment. Exercise also prevented the DOX-induced decreased activity of cardiac mitochondrial chain complexes I and V, and increased caspase 3 and 9 activities. DOX administration and exercise caused increased cardiac mitochondrial SOD activity. Exercise ameliorated liver mitochondrial complex activities. No alterations were observed in the measured MPTP and apoptosis-related proteins in heart and liver mitochondria. The results demonstrate that acute exercise protects against cardiac mitochondrial dysfunction, preserving mitochondrial phosphorylation capacity and attenuating DOX-induced decreased tolerance to MPTP opening.

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