mitochondrial permeability transition pore
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The mitochondrial permeability transition pore (mtPTP) plays a vital role in altering the structure and function of mitochondria. Cyclophilin D (CypD) is a mitochondrial protein that regulates mtPTP function and a known drug target for therapeutic studies involving mitochondria. While the effect of aromatase inhibition on the mtPTP has been studied previously, the effect of anastrozole on the mtPTP has not been completely elucidated. The role of anastrozole in modulating the mtPTP was evaluated by docking, molecular dynamics and network-guided studies using human CypD data. The peripheral blood mononuclear cells (PBMCs) of patients with mitochondrial disorders and healthy controls were treated with anastrozole and evaluated for mitochondrial permeability transition pore (mtPTP) function and apoptosis using a flow cytometer. Spectrophotometry was employed for estimating total ATP levels. The anastrozole-CypD complex is more stable than cyclosporin A (CsA)-CypD. Anastrozole performed better than cyclosporine in inhibiting mtPTP. Additional effects included inducing mitochondrial membrane depolarization and a reduction in mitochondrial swelling and superoxide generation, intrinsic caspase-3 activity and cellular apoptosis, along with an increase in ATP levels. Anastrozole may serve as a potential therapeutic agent for mitochondrial disorders and ameliorate the clinical phenotype by regulating the activity of mtPTP. However, further studies are required to substantiate our preliminary findings.Communicated by Ramaswamy H. Sarma.
- MeSH
- adenosintrifosfát metabolismus MeSH
- anastrozol farmakologie metabolismus MeSH
- cyklofiliny genetika metabolismus MeSH
- leukocyty mononukleární metabolismus MeSH
- lidé MeSH
- mitochondriální nemoci * metabolismus MeSH
- mitochondrie metabolismus MeSH
- peptidylprolylisomerasa F MeSH
- přechodový pór mitochondriální permeability * metabolismus farmakologie MeSH
- transportní proteiny mitochondriální membrány metabolismus farmakologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Values of the calcium retention capacity (CRC) of rat liver mitochondria are highly dependent on the experimental conditions used. When increasing amounts of added calcium chloride are used (1.25-10 nmol), the values of the CRC increase 3-fold. When calcium is added in 75 s intervals, the CRC values increase by 30 % compared with 150 s interval additions. CRC values are not dependent on the calcium/protein ratio in the measured sample in our experimental design. We also show that a more detailed evaluation of the fluorescence curves can provide new information about mitochondrial permeability transition pore opening after calcium is added.
- MeSH
- biologický transport MeSH
- jaterní mitochondrie metabolismus MeSH
- játra metabolismus MeSH
- krysa rodu rattus MeSH
- mitochondriální membrány metabolismus MeSH
- permeabilita MeSH
- přechodový pór mitochondriální permeability metabolismus MeSH
- transportní proteiny mitochondriální membrány metabolismus MeSH
- vápník metabolismus MeSH
- výzkumný projekt MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- hodnotící studie MeSH
Mitochondria play an important role in the cell aging process. Changes in calcium homeostasis and/or increased reactive oxygen species (ROS) production lead to the opening of mitochondrial permeability transition pore (MPTP), depolarization of the inner mitochondrial membrane, and decrease of ATP production. Our work aimed to monitor age-related changes in the Ca2+ ion effect on MPTP and the ability of isolated rat liver mitochondria to accumulate calcium. The mitochondrial calcium retention capacity (CRC) was found to be significantly affected by the age of rats. Measurement of CRC values of the rat liver mitochondria showed two periods when 3 to 17-week old rats were tested. 3-week and 17-week old rats showed lower CRC values than 7-week old animals. Similar changes were observed while testing calcium-induced swelling of rat liver mitochondria. These findings indicate that the mitochondrial energy production system is more resistant to calcium-induced MPTP opening accompanied by the damaging effect of ROS in adult rats than in young and aged animals.
The mitochondrial permeability transition pore (MPTP) is a calcium-dependent, ion non-selective membrane pore with a wide range of functions. Although the MPTP has been studied for more than 50 years, its molecular structure remains unclear. Short-term (reversible) opening of the MPTP protects cells from oxidative damage and enables the efflux of Ca2+ ions from the mitochondrial matrix and cell signaling. However, long-term (irreversible) opening induces processes leading to cell death. Ca2+ ions, reactive oxygen species, and changes in mitochondrial membrane potential regulate pore opening. The sensitivity of the pore to Ca2+ ions changes as an organism ages, and MPTP opening plays a key role in the pathogenesis of many diseases. Most studies of the MPTP have focused on elucidating its molecular structure. However, understanding the mechanisms that will inhibit the MPTP may improve the treatment of diseases associated with its opening. To evaluate the functional state of the MPTP and its inhibitors, it is therefore necessary to use appropriate methods that provide reproducible results across laboratories. This review summarizes our current knowledge of the function and regulation of the MPTP. The latter part of the review introduces two optimized methods for evaluating the functional state of the pore under standardized conditions.
Ca2+-induced opening of the mitochondrial permeability transition pore (MPTP) is involved in induction of apoptotic and necrotic processes. We studied sensitivity of MPTP to calcium using the model of Ca2+-induced, cyclosporine A-sensitive mitochondrial swelling. Presented data indicate that the extent of mitochondrial swelling (dA520/4 min) induced by addition of 25 µM Ca2+ is seven-fold higher in liver than in heart mitochondria (0.564 ± 0.08/0.077± 0.01). The extent of swelling induced by 100 µM Ca2+ was in liver tree times higher than in heart mitochondria (0.508±0.05/ 0.173±0.02). Cyclosporine A sensitivity showed that opening of the MPTP is involved. We may thus conclude that especially at low Ca2+ concentration heart mitochondria are more resistant to damaging effect of Ca2+ than liver mitochondria. These finding thus support hypothesis that there exist tissue specific strategies of cell protection against induction of the apoptotic and necrotic processes.
- MeSH
- cyklosporin farmakologie MeSH
- financování organizované MeSH
- gating iontového kanálu účinky léků MeSH
- jaterní mitochondrie metabolismus MeSH
- krysa rodu rattus MeSH
- potkani Wistar MeSH
- srdeční mitochondrie metabolismus MeSH
- transportní proteiny mitochondriální membrány metabolismus MeSH
- vápník farmakologie metabolismus MeSH
- zduření mitochondrií účinky léků MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- zvířata MeSH
Using a novel method for evaluating mitochondrial swelling (Drahota et al. 2012a) we studied the effect of calcium (Ca(2+)), phosphate (P(i)), and triiodothyronine (T(3)) on the opening of mitochondrial membrane permeability transition pore and how they interact in the activation of swelling process. We found that 0.1 mM P(i), 50 microM Ca(2+) and 25 microM T(3) when added separately increase the swelling rate to about 10 % of maximal values when all three factors are applied simultaneously. Our findings document that under experimental conditions in which Ca(2+) and P(i) are used as activating factors, the addition of T(3) doubled the rate of swelling. T(3) has also an activating effect on mitochondrial membrane potential. The T(3) activating effect was also found after in vivo application of T(3). Our data thus demonstrate that T(3) has an important role in opening the mitochondrial membrane permeability pore and activates the function of the two key physiological swelling inducers, calcium and phosphate ions.
- MeSH
- jaterní mitochondrie účinky léků metabolismus MeSH
- krysa rodu rattus MeSH
- potkani Wistar MeSH
- transportní proteiny mitochondriální membrány metabolismus MeSH
- trijodthyronin metabolismus farmakologie MeSH
- vápník metabolismus farmakologie MeSH
- vztah mezi dávkou a účinkem léčiva MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
The aim of the study was to examine the potential role of mitochondrial permeability transition pore (mPTP) in the cardioprotective effect of chronic continuous hypoxia (CH) against acute myocardial ischemia/reperfusion (I/R) injury. Adult male Wistar rats were adapted to CH for 3 weeks, while their controls were kept under normoxic conditions. Subsequently, they were subjected to I/R insult while being administered with mPTP inhibitor, cyclosporin A (CsA). Infarct size and incidence of ischemic and reperfusion arrhythmias were determined. Our results showed that adaptation to CH as well as CsA administration reduced myocardial infarct size in comparison to the corresponding control groups. However, administration of CsA did not amplify the beneficial effect of CH, suggesting that inhibition of mPTP opening contributes to the protective character of CH.
- MeSH
- chronická nemoc MeSH
- cyklosporin * farmakologie MeSH
- hypoxie * metabolismus MeSH
- infarkt myokardu metabolismus patologie prevence a kontrola MeSH
- krysa rodu rattus MeSH
- potkani Wistar * MeSH
- přechodový pór mitochondriální permeability * metabolismus MeSH
- reperfuzní poškození myokardu * metabolismus prevence a kontrola patologie MeSH
- srdeční mitochondrie metabolismus účinky léků patologie MeSH
- transportní proteiny mitochondriální membrány metabolismus MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Most of the experimental studies have revealed that female heart is more tolerant to ischemia/reperfusion (I/R) injury as compared with the male myocardium. It is widely accepted that mitochondrial dysfunction, and particularly mitochondrial permeability transition pore (MPTP) opening, plays a major role in determining the extent of cardiac I/R injury. The aim of the present study was, therefore, to analyze (i) whether calcium-induced swelling of cardiac mitochondria is sex-dependent and related to the degree of cardiac tolerance to I/R injury and (ii) whether changes in MPTP components-cyclophilin D (CypD) and ATP synthase-can be involved in this process. We have observed that in mitochondria isolated from rat male and female hearts the MPTP has different sensitivity to the calcium load. Female mitochondria are more resistant both in the extent and in the rate of the mitochondrial swelling at higher calcium concentration (200 µM). At low calcium concentration (50 µM) no differences were observed. Our data further suggest that sex-dependent specificity of the MPTP is not the result of different amounts of ATP synthase and CypD, or their respective ratio in mitochondria isolated from male and female hearts. Our results indicate that male and female rat hearts contain comparable content of MPTP and its regulatory protein CypD; parallel immunodetection revealed also the same contents of adenine nucleotide translocator or voltage-dependent anion channel. Increased resistance of female heart mitochondria thus cannot be explained by changes in putative components of MPTP, and rather reflects regulation of MPTP function.
- MeSH
- krysa rodu rattus MeSH
- sexuální faktory * MeSH
- srdeční mitochondrie metabolismus MeSH
- transportní proteiny mitochondriální membrány metabolismus MeSH
- vápník metabolismus MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Klíčová slova
- mitochondriální pór přechodné propustnosti,
- MeSH
- akutní nekrotizující pankreatitida patologie MeSH
- Alzheimerova nemoc etiologie MeSH
- amyotrofická laterální skleróza etiologie MeSH
- buňky metabolismus MeSH
- Huntingtonova nemoc etiologie MeSH
- ionty chemie MeSH
- kardiovaskulární nemoci MeSH
- mitochondriální membrány patologie MeSH
- mitochondrie fyziologie patologie MeSH
- nealkoholová steatóza jater etiologie MeSH
- oxidační stres MeSH
- Parkinsonova nemoc etiologie MeSH
- reperfuzní poškození myokardu farmakoterapie MeSH
- Reyeův syndrom etiologie MeSH
- salicylany toxicita MeSH
- syndromy suchého oka etiologie MeSH
- vápník chemie metabolismus MeSH
- Publikační typ
- práce podpořená grantem MeSH
- přehledy MeSH
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.
- MeSH
- jaterní mitochondrie účinky léků metabolismus MeSH
- játra metabolismus MeSH
- krysa rodu rattus MeSH
- mitochondrie metabolismus MeSH
- oxidační stres * MeSH
- transportní proteiny mitochondriální membrány účinky léků metabolismus MeSH
- vápník metabolismus farmakologie MeSH
- zduření mitochondrií účinky léků MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
