Palladacycles catalyse the oxidation of critical thiols of the mitochondrial membrane proteins and lead to mitochondrial permeabilization and cytochrome c release associated with apoptosis

2008 ◽  
Vol 417 (1) ◽  
pp. 247-256 ◽  
Author(s):  
Débora P. Santana ◽  
Priscila A. Faria ◽  
Edgar J. Paredes-Gamero ◽  
Antonio C. F. Caires ◽  
Iseli L. Nantes ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Cytochrome C ◽  
Disulfide Bonds ◽  
Mitochondrial Membrane ◽  
Apoptotic Cell ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Cytochrome C Release ◽  
Mitochondrial Permeabilization

Permeabilization of the mitochondrial membrane has been extensively associated with necrotic and apoptotic cell death. Similarly to what had been previously observed for B16F10-Nex2 murine melanoma cells, PdC (palladacycle compounds) obtained from the reaction of dmpa (N,N-dimethyl-1-phenethylamine) with the dppe [1,2-ethanebis(diphenylphosphine)] were able to induce apoptosis in HTC (hepatoma, tissue culture) cells, presenting anticancer activity in vitro. To elucidate cell site-specific actions of dmpa:dppe that could respond to the induction of apoptosis in cancer cells in the present study, we investigated the effects of PdC on isolated RLM (rat liver mitochondria). Our results showed that these palladacycles are able to induce a Ca2+-independent mitochondrial swelling that was not inhibited by ADP, Mg2+ and antioxidants. However, the PdC-induced mitochondrial permeabilization was partially prevented by pre-incubation with CsA (cyclosporin A), NEM (N-ethylmaleimide) and bongkreic acid and totally prevented by DTT (dithiothreitol). A decrease in the content of reduced thiol groups of the mitochondrial membrane proteins was also observed, as well as the presence of membrane protein aggregates in SDS/PAGE without lipid and GSH oxidation. FTIR (Fourier-transform IR) analysis of PdC-treated RLM demonstrated the formation of disulfide bonds between critical thiols in mitochondrial membrane proteins. Associated with the mitochondrial permeabilization, PdC also induced the release of cytochrome c, which is sensitive to inhibition by DTT. Besides the contribution to clarify the pro-apoptotic mechanism of PdC, this study shows that the catalysis of specific protein thiol cross-linkage is enough to induce mitochondrial permeabilization and cytochrome c release.

Geraniin induces apoptotic cell death in human lung adenocarcinoma A549 cells in vitro and in vivo

2013 ◽  
Vol 91 (12) ◽  
pp. 1016-1024 ◽  
Author(s):  
Jia Li ◽  
Siran Wang ◽  
Jimei Yin ◽  
Linna Pan
Keyword(s):  
Cytochrome C ◽  
Mitochondrial Membrane ◽  
Apoptotic Cell ◽  
A549 Cells ◽  
Tumor Growth Inhibition ◽  
Dependent Manner ◽  
Cytochrome C Release ◽  
Lung Adenocarcinoma A549

Geraniin has previously been reported to possess extensive biological activity. In this study, we reported that geraniin is an inhibitor of tumor activity in vitro and in vivo. Geraniin suppressed the proliferation of A549 cells in a dose- and time-dependent manner. Geraniin arrested the cell cycle in the S phase and induced a significant accumulation of reactive oxygen species (ROS), as well as an increased percentage of cells with mitochondrial membrane potential (MMP) disruption. Western blot analysis showed that geraniin inhibited Bcl-2 expression and induced Bax expression to disintegrate the outer mitochondrial membrane and cause cytochrome c release. Mitochondrial cytochrome c release was associated with the activation of caspase-9 and caspase-3 cascades. Additionally, geraniin resulted in tumor growth inhibition in A549 xenografts. Our results indicate cytotoxic activity of geraniin towards cancer cells in vitro and in vivo.

scholarly journals Synthetic and natural polyanions induce cytochrome c release from mitochondria in vitro and in situ

2011 ◽  
Vol 300 (5) ◽  
pp. C1193-C1203 ◽  
Author(s):  
Boris F. Krasnikov ◽  
Nickolay S. Melik-Nubarov ◽  
Lubava D. Zorova ◽  
Alevtina E. Kuzminova ◽  
Nickolay K. Isaev ◽  
...  
Keyword(s):  
Cytochrome C ◽  
Rat Liver ◽  
Mitochondrial Permeability Transition ◽  
Hydrophobic Interactions ◽  
Liver Mitochondria ◽  
Mitochondrial Swelling ◽  
Molar Ratio ◽  
Rat Liver Mitochondria ◽  
Cytochrome C Release

A synthetic polyanion composed of styrene, maleic anhydride, and methacrylic acid (molar ratio 56:37:7) significantly inhibited the respiration of isolated rat liver mitochondria in a time-dependent fashion that correlated with 1) collapse of the mitochondrial membrane potential and 2) high amplitude mitochondrial swelling. The process is apparently Ca2+ dependent. Since it is blocked by cyclosporin A, the process is ascribed to induction of the mitochondrial permeability transition. In mitoplasts, i.e., mitochondria lacking their outer membranes, the polyanion rapidly blocked respiration. After incubation of rat liver mitochondria with the polyanion, cytochrome c was released into the incubation medium. In solution, the polyanion modified by conjugation with fluorescein formed a complex with cytochrome c. Addition of the polyanion to cytochrome c-loaded phosphatidylcholine/cardiolipin liposomes induced the release of the protein from liposomal membrane evidently due to coordinated interplay of Coulomb and hydrophobic interactions of the polymer with cytochrome c. We conclude that binding of the polyanion to cytochrome c renders it inactive in the respiratory chain due to exclusion from its native binding sites. Apparently, the polyanion interacts with cytochrome c in mitochondria and releases it to the medium through breakage of the outer membrane as a result of severe swelling. Similar properties were demonstrated for the natural polyanion, tobacco mosaic virus RNA. An electron microscopy study confirmed that both polyanions caused mitochondrial swelling. Exposure of cerebellar astroglial cells in culture to the synthetic polyanion resulted in cell death, which was associated with nuclear fragmentation.

Cytochrome c release from rat liver mitochondria is compromised by increased saturated cardiolipin species induced by sucrose feeding

2015 ◽  
Vol 309 (9) ◽  
pp. E777-E786 ◽  
Author(s):  
Angélica Ruiz-Ramírez ◽  
Miguel-Angel Barrios-Maya ◽  
Ocarol López-Acosta ◽  
Dora Molina-Ortiz ◽  
Mohammed El-Hafidi
Keyword(s):  
Cytochrome C ◽  
Superoxide Radical ◽  
Lipid Membrane ◽  
Liver Mitochondria ◽  
Membrane Lipid ◽  
Rat Liver Mitochondria ◽  
Ros Generation ◽  
Cytochrome C Release ◽  
Mitochondrial Inner Membrane ◽  
Sucrose Feeding

Cytochrome c release from mitochondria has been described to be related to reactive oxygen species (ROS) generation. With ROS generation being increased in fatty liver from sucrose-fed (SF) rats, we hypothesized that cytochrome c release might be positively associated with H2O2 generation from SF mitochondria. Surprisingly, cytochrome c release from mitochondria of SF liver was found to be significantly lower compared with control (C) mitochondria oxidizing pyruvate/malate or succinate. Exposure of mitochondria to exogenous superoxide radical generated by the xanthine/xanthine oxidase system elicits a dose-response cytochrome c release in both control and SF mitochondria, but cytochrome c release remains lower in SF mitochondria compared with C mitochondria. Furthermore, the addition of ebselen, PEG-catalase, or catalase, a H2O2 scavenger, significantly reduces cytochrome c release from C and SF mitochondria. Our results suggest that both intra- and extramitochondrial H2O2 are involved in cytochrome c release, but the persisting difference between C and SF levels can be attributed to the differences in cardiolipin compositions. Indeed, the ratio of palmitic acid-rich cardiolipin species was found to be increased in lipid membrane from SF mitochondria compared with C mitochondria, whereas that of linoleic acid-rich cardiolipin species was found decreased. In addition, the content of tafazzin, a protein responsible for cardiolipin remodeling, was decreased in SF mitochondria. Therefore, we conclude that the changes observed in the composition of cardiolipin molecular species in SF mitochondria may be involved in cytochrome c interaction with mitochondrial inner membrane lipid and in its reduced release from SF mitochondria.

THE INHIBITION OF OXIDATIVE AND PHOSPHORYLATIVE ENZYMES IN RAT LIVER MITOCHONDRIA BY AMINOAZOBENZENE DERIVATIVES

1960 ◽  
Vol 38 (1) ◽  
pp. 1-11 ◽  
Author(s):  
W. C. McMurray
Keyword(s):  
Cytochrome C ◽  
Rat Liver ◽  
Pyridine Nucleotide ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Succinate Oxidation ◽  
Metabolic Block ◽  
Liver Carcinogen ◽  
Mitochondrial Dehydrogenase Activity

The liver carcinogen, dimethylaminoazobenzene, inhibited in vitro the oxidation of a variety of pyridine nucleotide linked substrates of rat liver mitochondria without affecting the process of oxidative phosphorylation. Cytochrome c oxidase activity was not inhibited by the carcinogen, nor was the succinoxidase activity, but the phosphorylation accompanying succinate oxidation was uncoupled. Similar effects were noted with other aminoazobenzene derivatives, but did not appear to be correlated with the ability of the compounds to evoke tumors.The site of the respiratory inhibition by dimethylaminoazobenzene appears to be at the level between reduced pyridine nucleotide and cytochrome c in the respiratory chain. Mitochondrial dehydrogenase activity was not inhibited, while the oxidation of reduced diphosphopyridine nucleotide was markedly decreased. The reduction of the electron acceptor, ferricyanide, by pyridine nucleotide linked substrates was also strongly inhibited but the reduction of tetrazolium compounds was not affected. The latter observations suggest that dimethylaminoazobenzene produces a metabolic block between reduced flavin and cytochrome c in the mitochondrial electron transport system.

scholarly journals Influence of starvation and clofibrate administration on oxidative phosphorylation by rat liver mitochondria

1980 ◽  
Vol 190 (1) ◽  
pp. 191-198 ◽  
Author(s):  
B K A Rasheed ◽  
S Chhabra ◽  
C K R Kurup
Keyword(s):  
Cytochrome C ◽  
Binding Sites ◽  
Liver Mitochondria ◽  
Potassium Ferricyanide ◽  
Rat Liver Mitochondria ◽  
Albino Rats ◽  
Succinate Dehydrogenase Activity ◽  
Whole Cells ◽  
High Affinity

Whole cells, homogenates and mitochondrial obtained from the livers of albino rats which were starved for 6 days or more showed a 50% decrease in oxidative activity. The decrease could be corrected by the addition of cytochrome c in vitro. The phosphorylative activity of mitochondria remained unaffected. The decrease in oxidative rate was not observed when starving animals were given the anti-hypercholesterolaemic drug clofibrate. The total cellular concentration of cytochrome c was not affected by starvation. However, the concentration of the pigment in hepatic mitochondria isolated from starving animals was less than half that in normal mitochondria. Clofibrate-treated animals did not show a decreased concentration of cytochrome c in hepatic mitochondria. Mitochondria isolated from starving animals, though deficient in cytochrome c, did not show any decrease in succinate dehydrogenase activity or in the rate of substrate-dependent reduction of potassium ferricyanide or attendant phosphorylation. In coupled mitochondria, ferricyanide may not accept electrons from the cytochrome c in the respiratory chain. Starvation decreases the concentration of high-affinity binding sites for cytochrome c on the mitochondrial membrane. The dissociation constant increases in magnitude.

Cytochrome c methylation

1989 ◽  
Vol 67 (9) ◽  
pp. 602-611 ◽  
Author(s):  
Woon Ki Pair ◽  
Young-Bong Cho ◽  
Blaise Frost ◽  
Sangduk Kim
Keyword(s):  
Cytochrome C ◽  
Liver Mitochondria ◽  
In Vitro Translation ◽  
Rat Liver Mitochondria ◽  
General Terms ◽  
Apocytochrome C ◽  
Enzymatic Methylation ◽  
Stokes Radius

In this review, protein methylation is outlined in general terms, highlighting the major amino acids that are methylated and some of the proteins in which they are found. The majority of the review examines the methylation of cytochrome c at Lys-77 of lower eukaryotes as a possible model for methylation studies. Early work involving the purification and characterization of the methyltransferase responsible for this methylation indicated cytochrome c was methylated posttranslationally, yet prior to import into the mitochondria. Methylation in vitro occurred only at the in vivo methylation site and only on cytochrome c. Later studies using in vitro translated apocytochrome c revealed that methylated, as compared with unmethylated, apocytochrome c was imported preferentially into yeast, but not rat liver, mitochondria. Efforts to discover the reasons for this preference have shown that methylation of apocytochrome c dramatically lowers its isoelectric point (against a predicted increase) and decrease its Stokes radius. A possible mechanism for these differences involving the disruption of hydrogen bonds is presented here with space-filling models. Finally, the in vivo significance of this modification is also discussed.Key words: yeast iso-1-apocytochrome c, enzymatic methylation, in vitro translation, protein methylase III, pI change.

scholarly journals In VitroToxicity of Epigallocatechin Gallate in Rat Liver Mitochondria and Hepatocytes

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Otto Kucera ◽  
Vojtech Mezera ◽  
Alena Moravcova ◽  
Rene Endlicher ◽  
Halka Lotkova ◽  
...  
Keyword(s):  
Rat Liver ◽  
Mitochondrial Membrane ◽  
Epigallocatechin Gallate ◽  
Rat Hepatocytes ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Main Compound ◽  
Ros Formation ◽  
High Doses

Epigallocatechin-3-gallate (EGCG) is the main compound of green tea with well-described antioxidant, anti-inflammatory, and tumor-suppressing properties. However, EGCG at high doses was reported to cause liver injury. In this study, we evaluated the effect of EGCG on primary culture of rat hepatocytes and on rat liver mitochondria in permeabilized hepatocytes. The 24-hour incubation with EGCG in concentrations of 10 μmol/L and higher led to signs of cellular injury and to a decrease in hepatocyte functions. The effect of EGCG on the formation of reactive oxygen species (ROS) was biphasic. While low doses of EGCG decreased ROS production, the highest tested dose induced a significant increase in ROS formation. Furthermore, we observed a decline in mitochondrial membrane potential in cells exposed to EGCG when compared to control cells. In permeabilized hepatocytes, EGCG caused damage of the outer mitochondrial membrane and an uncoupling of oxidative phosphorylation. EGCG in concentrations lower than 10 μmol/L was recognized as safe for hepatocytesin vitro.

Ceramide induces cytochrome c release from isolated mitochondria

1999 ◽  
Vol 66 ◽  
pp. 27-31 ◽  
Author(s):  
Christoph Richter ◽  
Pedram Ghafourifar
Keyword(s):  
Cytochrome C ◽  
Membrane Integrity ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Cytochrome C Release ◽  
Mitochondrial Oxygen Consumption ◽  
Mitochondrial Functions ◽  
Cyt C ◽  
C6 Ceramide

This chapter addresses the role of mitochondria in apoptosis. Emphasis is put on the recently observed influence of ceramides on mitochondrial functions. We report here that N-acetylsphingosine (C2-ceramide), N-hexanoylsphingosine (C6-ceramide) and, to a much lesser extent, C2-dihydroceramide, induce cytochrome c (cyt c) release from isolated rat liver mitochondria. Ceramide-induced cyt c release is prevented by a low concentration of Bcl-2. The release takes place when cyt c is oxidized, but not when it is reduced. Upon cyt c release mitochondrial oxygen consumption, mitochondrial transmembrane potential (ΔΨm) and Ca2+ retention are diminished. Bcl-2 prevents, and addition of cyt c reverses, the alteration of these mitochondrial functions. In ATP-energized mitochondria ceramides do not alter ΔΨm, neither when cyt c is oxidized nor when it is reduced. This rules out a non-specific disturbance by ceramides of mitochondrial-membrane integrity. It is concluded that some of the apoptogenic properties of ceramides are mediated via their interaction with mitochondrial cyt c followed by its release.

scholarly journals Cytochrome c release from isolated rat liver mitochondria can occur independently of outer-membrane rupture: possible role of contact sites

2000 ◽  
Vol 348 (2) ◽  
pp. 343-350 ◽  
Author(s):  
Elena DORAN ◽  
Andrew P. HALESTRAP
Keyword(s):  
Cytochrome C ◽  
Rat Liver ◽  
Adenine Nucleotide ◽  
Permeability Transition ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Voltage Dependent Anion Channel ◽  
Cytochrome C Release ◽  
Membrane Rupture ◽  
Contact Sites

Percoll-purified rat liver mitochondria were shown to contain BAX dimer and rapidly (< 2 min) release 5-10% of their cytochrome c when incubated in a standard KCl incubation medium under energized conditions. This release was not accompanied by release of adenylate kinase (AK), another intermembrane protein, and was not inhibited by Mg2+, dATP, inhibitors of the permeability transition or ligands of the peripheral benzodiazepine receptor. However, release was greatly reduced by the presence of 5% (w/v) dextran (40 kDa), which caused a decrease in the light scattering (A520) of mitochondrial suspensions. Dextran also inhibited both mitochondrial oxidation of exogenous ferrocytochrome c in the presence of rotenone and antimycin, and respiratory-chain-driven reduction of exogenous ferricytochrome c. Hypo-osmotic medium or digitonin treatment of mitochondria caused a large additional release of both cytochrome c and AK that was not blocked by dextran. Polyaspartate, which stabilizes the low conductance state of the voltage-dependent anion channel (VDAC), increased cytochrome c release. VDAC and BAX are both found at the contact sites between the inner and outer membranes and dextran is known to stabilize these contact sites in isolated mitochondria. Thus our data suggest that regulation of a specific permeability pathway for cytochrome c may be mediated by changes in protein-protein interactions within contact sites. The adenine nucleotide translocase is known to bind to VDAC and thus provides an additional link between the specific cytochrome c release pathway and the permeability transition.

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