scholarly journals Factors Affecting the Function of the Mitochondrial Membrane Permeability Transition Pore and Their Role in Evaluation of Calcium Retention Capacity Values

2020 ◽  
pp. 491-499
Author(s):  
Z DRAHOTA ◽  
R ENDLICHER ◽  
O KUČERA ◽  
D RYCHTRMOC ◽  
Z ČERVINKOVÁ
Keyword(s):  
Mitochondrial Permeability Transition ◽  
Permeability Transition Pore ◽  
Permeability Transition ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Experimental Conditions ◽  
Protein Ratio ◽  
Retention Capacity ◽  
Calcium Retention ◽  
Calcium Retention Capacity

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.

scholarly journals Mitochondria Permeabilization by a Novel Polycation Peptide BTM-P1

2005 ◽  
Vol 280 (16) ◽  
pp. 15579-15586 ◽  
Author(s):  
Victor V. Lemeshko ◽  
Mauricio Arias ◽  
Sergio Orduz
Keyword(s):  
Membrane Potential ◽  
Cyclosporin A ◽  
Mitochondrial Permeability Transition ◽  
Permeability Transition Pore ◽  
Permeability Transition ◽  
Liver Mitochondria ◽  
Peptide Sequence ◽  
Rat Liver Mitochondria ◽  
Tryptophan Residue ◽  
Inner Membrane

Bacillus thuringiensissubsp.medellinis known to produce the Cry11Bb protein of 94 kDa, which is toxic for mosquito larvae due to permeabilization of the plasma membrane of midgut epithelial cells. Earlier we found that a 2.8-kDa novel peptide BTM-P1, which was artificially synthesized taking into account the primary structure of Cry11Bb endotoxin, is active against several species of bacteria. In this work we show that BTM-P1 induces cyclosporin A-insensitive swelling of rat liver mitochondria in various salt solutions but not in the sucrose medium. Inorganic phosphate and Ca2+significantly increased this effect of the peptide. The uncoupling action of BTM-P1 on oxidative phosphorylation was stronger in the potassium-containing media and correlated with a decrease of the inner membrane potential of mitochondria. In isotonic KNO3, KCl, or NH4NO3media, a complete drop of the inner membrane potential was observed at 1–2 μg/ml of the peptide. The peptide-induced swelling was increased by energization of mitochondria in the potassium-containing media, but it was inhibited in the NaNO3, NH4NO3, and Tris-NO3media. All mitochondrial effects of the peptide were completely prevented by adding a single N-terminal tryptophan residue to the peptide sequence. We suggest a mechanism of membrane permeabilization that includes a transmembrane- and surface potential-dependent insertion of the polycation peptide into the lipid bilayer and its oligomerization leading to formation of ion channels and also to the mitochondrial permeability transition pore opening in a cyclosporin A-insensitive manner.

scholarly journals Modification of calcium retention capacity of rat liver mitochondria by phosphate and tert-butyl hydroperoxide

2019 ◽  
pp. 59-65 ◽  
Author(s):  
R. Endlicher ◽  
Z. Drahota ◽  
Z. Červinková
Keyword(s):  
Rat Liver ◽  
Cyclosporine A ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Retention Capacity ◽  
Butyl Hydroperoxide ◽  
Calcium Retention ◽  
Tert Butyl ◽  
Tert Butyl Hydroperoxide ◽  
Calcium Retention Capacity

By determining the calcium retention capacity (CRC) of rat liver mitochondria, we confirmed and extended previous observations describing the activation of mitochondrial swelling by phosphate and tert-butyl hydroperoxide (t-BHP). Using CRC measurements, we showed that both phosphate and t-BHP decrease the extent of calcium accumulation required for the full mitochondrial permeability transition pore (MPTP) opening to 35 % of control values and to only 15 % when both phosphate and t-BHP are present in the medium. When changes in fluorescence were evaluated at higher resolution, we observed that in the presence of cyclosporine A fluorescence values return after each Ca(2+) addition to basal values obtained before the Ca(2+) addition. This indicates that the MPTP remains closed. However, in the absence of cyclosporine A, the basal fluorescence after each Ca(2+) addition continuously increased. This increase was potentiated both by phosphate and t-BHP until the moment when the concentration of intramitochondrial calcium required for the full opening of the MPTP was reached. We conclude that in the absence of cyclosporine A, the MPTP is slowly opened after each Ca(2+) addition and that this rate of opening can be modified by various factors such as the composition of the media and the experimental protocol used.

scholarly journals Enhanced resistance to Ca2+-induced mitochondrial permeability transition in the long-lived red-footed tortoise Chelonoidis carbonaria

2021 ◽  
Author(s):  
Marina R. Sartori ◽  
Claudia D.C. Navarro ◽  
Roger F. Castilho ◽  
Anibal E. Vercesi
Keyword(s):  
Rat Liver ◽  
Mitochondrial Permeability Transition ◽  
Permeability Transition ◽  
Liver Mitochondria ◽  
System Capacity ◽  
Rat Liver Mitochondria ◽  
Cyclophilin D ◽  
Retention Capacity ◽  
Mitochondrial Permeability ◽  
Enhanced Resistance

The interaction between supraphysiological cytosolic Ca2+ levels and mitochondrial redox imbalance mediates the mitochondrial permeability transition (MPT). MPT is involved in cell death, diseases, and aging. This study compared the liver mitochondrial Ca2+ retention capacity and oxygen consumption in the long-lived red-footed tortoise (Chelonoidis carbonaria) to the rat as a reference standard. Mitochondrial Ca2+ retention capacity, a quantitative measure of MPT sensitivity, was remarkably higher in tortoises than rats. This difference was minimized in the presence of the MPT inhibitors, ADP and cyclosporine A. However, the Ca2+ retention capacities of tortoise and rat liver mitochondria were similar when both MPT inhibitors were present simultaneously. NADH-linked phosphorylating respiration rates of tortoise liver mitochondria represented only 30% of the maximal electron transport system capacity, indicating a limitation imposed by the phosphorylation system. These results suggested underlying differences in putative MPT structural components (e.g. ATP synthase, adenine nucleotide translocase (ANT), and cyclophilin D) between tortoises and rats. Indeed, in tortoise mitochondria, titrations of inhibitors of the oxidative phosphorylation components revealed a higher limitation of ANT. Furthermore, cyclophilin D activity was approximately 70% lower in tortoises than in rats. Investigation of critical properties of mitochondrial redox control that affect MPT demonstrated that tortoise and rat liver mitochondria exhibited similar rates of H2O2 release and glutathione redox status. Overall, our findings suggest that constraints imposed by ANT and cyclophilin D, putative components or regulators of the MPT pore, are associated with the enhanced resistance to Ca2+-induced MPT in tortoises.

scholarly journals The Effects of PK11195 and Protoporphyrin IX Can Modulate Chronic Alcohol Intoxication in Rat Liver Mitochondria under the Opening of the Mitochondrial Permeability Transition Pore

Cells ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1774
Author(s):  
Yulia Baburina ◽  
Irina Odinokova ◽  
Olga Krestinina
Keyword(s):  
Rat Liver ◽  
Mitochondrial Permeability Transition Pore ◽  
Mitochondrial Permeability Transition ◽  
Permeability Transition Pore ◽  
Permeability Transition ◽  
Alcohol Exposure ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Chronic Alcohol ◽  
Mitochondrial Permeability

Decades of active research have shown that mitochondrial dysfunction, the associated oxidative stress, impaired anti-stress defense mechanisms, and the activation of the proapoptotic signaling pathways underlie pathological changes in organs and tissues. Pathologies caused by alcohol primarily affect the liver. Alcohol abuse is the cause of many liver diseases, such as steatosis, alcoholic steatohepatitis, fibrosis, cirrhosis, and, potentially, hepatocellular cancer. In this study, the effect of chronic alcohol exposure on rat liver mitochondria was investigated. We observed an ethanol-induced increase in sensitivity to calcium, changes in the level of protein kinase Akt and GSK-3β phosphorylation, an induction of the mitochondrial permeability transition pore (mPTP), and strong alterations in the expression of mPTP regulators. Moreover, we also showed an enhanced effect of PK11195 and PPIX, on the parameters of the mPTP opening in rat liver mitochondria (RLM) isolated from ethanol-treated rats compared to the RLM from control rats. We suggest that the results of this study could help elucidate the mechanisms of chronic ethanol action on the mitochondria and contribute to the development of new therapeutic strategies for treating the effects of ethanol-related diseases.

scholarly journals New Properties and Mitochondrial Targets of Polyphenol Agrimoniin as a Natural Anticancer and Preventive Agent

Pharmaceutics ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 2089
Author(s):  
Tatiana A. Fedotcheva ◽  
Olga P. Sheichenko ◽  
Nadezhda I. Fedotcheva
Keyword(s):  
Mitochondrial Permeability Transition ◽  
Permeability Transition Pore ◽  
Permeability Transition ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Dependent Manner ◽  
Anticancer Activities ◽  
Concentration Dependent Manner ◽  
Succinate Oxidation ◽  
Mitochondrial Functions

Agrimoniin is a polyphenol from the group of tannins with antioxidant and anticancer activities. It is assumed that the anticancer action of agrimoniin is associated with the activation of mitochondria-dependent apoptosis, but its mitochondrial targets have not been estimated. We examined the direct influence of agrimoniin on different mitochondrial functions, including the induction of the mitochondrial permeability transition pore (MPTP) as the primary mechanism of mitochondria-dependent apoptosis. Agrimoniin was isolated from Agrimonia pilosa Ledeb by multistep purification. The content of agrimoniin in the resulting substance reached 80%, as determined by NMR spectroscopy. The cytotoxic effect of purified agrimoniin was confirmed on the cultures of K562 and HeLa cancer cells by the MTT assay. When tested on isolated rat liver mitochondria, agrimoniin at a low concentration (10 µM) induced the low-amplitude swelling, which was inhibited by the MPTP inhibitors ADP and cyclosporine A, activated the opening of MPTP by calcium ions and stimulated the respiration supported by succinate oxidation. Also, agrimoniin reduced the electron acceptor DCPIP in a concentration-dependent manner and chelated iron ions. Owing to all these properties, agrimoniin can stimulate apoptosis or activate mitochondrial functions, which can be helpful in the prevention and elimination of stagnant pathological states.

scholarly journals Age-Dependent Changes in the Function of Mitochondrial Membrane Permeability Transition Pore in Rat Liver Mitochondria

2021 ◽  
pp. 905-911
Author(s):  
R. Endlicher ◽  
Z. Drahota ◽  
O. Kučera ◽  
Z. Červinková
Keyword(s):  
Rat Liver ◽  
Mitochondrial Membrane ◽  
Mitochondrial Permeability Transition ◽  
Permeability Transition Pore ◽  
Permeability Transition ◽  
Liver Mitochondria ◽  
Cell Aging ◽  
Rat Liver Mitochondria ◽  
Age Related ◽  
Old Rats

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 to17-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.

scholarly journals Chronic ethanol consumption enhances sensitivity to Ca2+-mediated opening of the mitochondrial permeability transition pore and increases cyclophilin D in liver

2010 ◽  
Vol 299 (4) ◽  
pp. G954-G966 ◽  
Author(s):  
Adrienne L. King ◽  
Telisha M. Swain ◽  
Dale A. Dickinson ◽  
Mathieu J. Lesort ◽  
Shannon M. Bailey
Keyword(s):  
Gene Expression ◽  
Mitochondrial Permeability Transition Pore ◽  
Mitochondrial Permeability Transition ◽  
Permeability Transition Pore ◽  
Permeability Transition ◽  
Liver Mitochondria ◽  
Cyclophilin D ◽  
Retention Capacity ◽  
Mitochondrial Permeability ◽  
Chronic Ethanol Consumption

Chronic ethanol consumption increases mitochondrial oxidative stress and sensitivity to form the mitochondrial permeability transition pore (MPTP). The mechanism responsible for increased MPTP sensitivity in ethanol-exposed mitochondria and its relation to mitochondrial Ca2+ handling is unknown. Herein, we investigated whether increased sensitivity to MPTP induction in liver mitochondria from ethanol-fed rats compared with controls is related to an ethanol-dependent change in mitochondrial Ca2+ accumulation. Liver mitochondria were isolated from control and ethanol-fed rats, and Ca2+-mediated induction of the MPTP and mitochondrial Ca2+ retention capacity were measured. Levels of proposed MPTP proteins as well as select pro- and antiapoptotic proteins were measured along with gene expression. We observed increased steatosis and TUNEL-stained nuclei in liver of ethanol-fed rats compared with controls. Liver mitochondria from ethanol-fed rats had increased levels of proapoptotic Bax protein and reduced Ca2+ retention capacity compared with control mitochondria. We observed increased cyclophilin D (Cyp D) gene expression in liver and protein in mitochondria from ethanol-fed animals compared with controls, whereas there was no change in the adenine nucleotide translocase and voltage-dependent anion channel. Together, these results suggest that enhanced sensitivity to Ca2+-mediated MPTP induction may be due, in part, to higher Cyp D levels in liver mitochondria from ethanol-fed rats. Therefore, therapeutic strategies aimed at normalizing Cyp D levels may be beneficial in preventing ethanol-dependent mitochondrial dysfunction and liver injury.

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