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Sample records for brain liver mitochondria

  1. Agmatine transport in brain mitochondria: a different mechanism from that in liver mitochondria.

    PubMed

    Battaglia, V; Grancara, S; Mancon, M; Cravanzola, C; Colombatto, S; Grillo, M A; Tempera, G; Agostinelli, E; Toninello, A

    2010-02-01

    The diamine agmatine (AGM), exhibiting two positive charges at physiological pH, is transported into rat brain mitochondria (RBM) by an electrophoretic mechanism, requiring high membrane potential values and exhibiting a marked non-ohmic force-flux relationship. The mechanism of this transport apparently resembles that observed in rat liver mitochondria (RLM), but there are several characteristics that strongly suggest the presence of a different transporter of agmatine in RBM. In this type of mitochondria, the extent of initial binding and total accumulation is higher and lower, respectively, than that in liver; saturation kinetics and the flux-voltage relationship also exhibit different trends, whereas idazoxan and putrescine, ineffective in RLM, act as inhibitors. The characteristics of agmatine uptake in RBM lead to the conclusion that its transporter is a channel with two asymmetric energy barriers, showing some characteristics similar to those of the imidazoline receptor I(2) and the sharing with the polyamine transporter. PMID:19997762

  2. Effects of Various Kynurenine Metabolites on Respiratory Parameters of Rat Brain, Liver and Heart Mitochondria

    PubMed Central

    Baran, Halina; Staniek, Katrin; Bertignol-Spörr, Melanie; Attam, Martin; Kronsteiner, Carina; Kepplinger, Berthold

    2016-01-01

    Previously, we demonstrated that the endogenous glutamate receptor antagonist kynurenic acid dose-dependently and significantly affected rat heart mitochondria. Now we have investigated the effects of L-tryptophan, L-kynurenine, 3-hydroxykynurenine and kynurenic, anthranilic, 3-hydroxyanthranilic, xanthurenic and quinolinic acids on respiratory parameters (ie, state 2, state 3), respiratory control index (RC) and ADP/oxygen ratio in brain, liver and heart mitochondria of adult rats. Mitochondria were incubated with glutamate/malate (5 mM) or succinate (10 mM) and in the presence of L-tryptophan metabolites (1 mM) or in the absence, as control. Kynurenic and anthranilic acids significantly reduced RC values of heart mitochondria in the presence of glutamate/malate. Xanthurenic acid significantly reduced RC values of brain mitochondria in the presence of glutamate/malate. Furthermore, 3-hydroxykynurenine and 3-hydroxyanthranilic acid decreased RC values of brain, liver and heart mitochondria using glutamate/malate. In the presence of succinate, 3-hydroxykynurenine and 3-hydroxyanthranilic acid affected RC values of brain mitochondria, whereas in liver and heart mitochondria only 3-hydroxykynurenine lowered RC values significantly. Furthermore, lowered ADP/oxygen ratios were observed in brain mitochondria in the presence of succinate with 3-hydroxykynurenine and 3-hydroxyanthranilic acid, and to a lesser extent with glutamate/malate. In addition, 3-hydroxyanthranilic acid significantly lowered the ADP/oxygen ratio in heart mitochondria exposed to glutamate/malate, while in the liver mitochondria only a mild reduction was found. Tests of the influence of L-tryptophan and its metabolites on complex I in liver mitochondria showed that only 3-hydroxykynurenine, 3-hydroxyanthranilic acid and L-kynurenine led to a significant acceleration of NADH-driven complex I activities. The data indicate that L-tryptophan metabolites had different effects on brain, liver and heart

  3. Effects of Various Kynurenine Metabolites on Respiratory Parameters of Rat Brain, Liver and Heart Mitochondria.

    PubMed

    Baran, Halina; Staniek, Katrin; Bertignol-Spörr, Melanie; Attam, Martin; Kronsteiner, Carina; Kepplinger, Berthold

    2016-01-01

    Previously, we demonstrated that the endogenous glutamate receptor antagonist kynurenic acid dose-dependently and significantly affected rat heart mitochondria. Now we have investigated the effects of L-tryptophan, L-kynurenine, 3-hydroxykynurenine and kynurenic, anthranilic, 3-hydroxyanthranilic, xanthurenic and quinolinic acids on respiratory parameters (ie, state 2, state 3), respiratory control index (RC) and ADP/oxygen ratio in brain, liver and heart mitochondria of adult rats. Mitochondria were incubated with glutamate/malate (5 mM) or succinate (10 mM) and in the presence of L-tryptophan metabolites (1 mM) or in the absence, as control. Kynurenic and anthranilic acids significantly reduced RC values of heart mitochondria in the presence of glutamate/malate. Xanthurenic acid significantly reduced RC values of brain mitochondria in the presence of glutamate/malate. Furthermore, 3-hydroxykynurenine and 3-hydroxyanthranilic acid decreased RC values of brain, liver and heart mitochondria using glutamate/malate. In the presence of succinate, 3-hydroxykynurenine and 3-hydroxyanthranilic acid affected RC values of brain mitochondria, whereas in liver and heart mitochondria only 3-hydroxykynurenine lowered RC values significantly. Furthermore, lowered ADP/oxygen ratios were observed in brain mitochondria in the presence of succinate with 3-hydroxykynurenine and 3-hydroxyanthranilic acid, and to a lesser extent with glutamate/malate. In addition, 3-hydroxyanthranilic acid significantly lowered the ADP/oxygen ratio in heart mitochondria exposed to glutamate/malate, while in the liver mitochondria only a mild reduction was found. Tests of the influence of L-tryptophan and its metabolites on complex I in liver mitochondria showed that only 3-hydroxykynurenine, 3-hydroxyanthranilic acid and L-kynurenine led to a significant acceleration of NADH-driven complex I activities. The data indicate that L-tryptophan metabolites had different effects on brain, liver and heart

  4. Cyclophilin D-Sensitive Mitochondrial Permeability Transition in Adult Human Brain and Liver Mitochondria

    PubMed Central

    Morota, Saori; Chen, Li; Matsuyama, Nagahisa; Suzuki, Yoshiaki; Nakajima, Satoshi; Tanoue, Tadashi; Omi, Akibumi; Shibasaki, Futoshi; Shimazu, Motohide; Ikeda, Yukio; Uchino, Hiroyuki; Elmér, Eskil

    2011-01-01

    Abstract The mitochondrial permeability transition (mPT) is considered to be a major cause of cell death under a variety of pathophysiological conditions of the central nervous system (CNS) and other organs. Pharmacological inhibition or genetic knockout of the matrix protein cyclophilin D (CypD) prevents mPT and cell degeneration in several models of brain injury. If these findings in animal models are translatable to human disease, pharmacological inhibition of mPT offers a promising therapeutic target. The objective of this study was to validate the presence of a CypD-sensitive mPT in adult human brain and liver mitochondria. In order to perform functional characterization of human mitochondria, fresh tissue samples were obtained during hemorrhage or tumor surgery and mitochondria were rapidly isolated. Mitochondrial calcium retention capacity, a quantitative assay for mPT, was significantly increased by the CypD inhibitor cyclosporin A in both human brain and liver mitochondria, whereas thiol-reactive compounds and oxidants sensitized mitochondria to calcium-induced mPT. Brain mitochondria underwent swelling upon calcium overload, which was reversible upon calcium removal. To further explore mPT of human mitochondria, liver mitochondria were demonstrated to exhibit several classical features of the mPT phenomenon, such as calcium-induced loss of membrane potential and respiratory coupling, as well as release of the pro-apoptotic protein cytochrome c. We concluded that adult viable human brain and liver mitochondria possess an active CypD-sensitive mPT. Our findings support the rationale of CypD and mPT inhibition as pharmacological targets in acute and chronic neurodegeneration. PMID:21121808

  5. Effect of peroxides on spermine transport in rat brain and liver mitochondria.

    PubMed

    Battaglia, Valentina; Tibaldi, Elena; Grancara, Silvia; Zonta, Francesca; Brunati, Anna Maria; Martinis, Pamela; Bragadin, Marcantonio; Grillo, Maria Angelica; Tempera, Giampiero; Agostinelli, Enzo; Toninello, Antonio

    2012-02-01

    The polyamine spermine is transported into the matrix of various types of mitochondria by a specific uniporter system identified as a protein channel. This mechanism is regulated by the membrane potential; other regulatory effectors are unknown. This study analyzes the transport of spermine in the presence of peroxides in both isolated rat liver and brain mitochondria, in order to evaluate the involvement of the redox state in this mechanism, and to compare its effect in both types of mitochondria. In liver mitochondria peroxides are able to inhibit spermine transport. This effect is indicative of redox regulation by the transporter, probably due to the presence of critical thiol groups along the transport pathway, or in close association with it, with different accessibility for the peroxides and performing different functions. In brain mitochondria, peroxides have several effects, supporting the hypothesis of a different regulation of spermine transport. The fact that peroxovanadate can inhibit tyrosine phosphatases in brain mitochondria suggests that mitochondrial spermine transport is regulated by tyrosine phosphorylation in this organ. In this regard, the evaluation of spermine transport in the presence of Src inhibitors suggests the involvement of Src family kinases in this process. It is possible that phosphorylation sites for Src kinases are present in the channel pathway and have an inhibitory effect on spermine transport under regulation by Src kinases. The results of this study suggest that the activity of the spermine transporter probably depends on the redox and/or tyrosine phosphorylation state of mitochondria, and that its regulation may be different in distinct organs. PMID:21809072

  6. An analysis of the effects of Mn{sup 2+} on oxidative phosphorylation in liver, brain, and heart mitochondria using state 3 oxidation rate assays

    SciTech Connect

    Gunter, Thomas E.; Gerstner, Brent; Lester, Tobias; Wojtovich, Andrew P.; Malecki, Jon; Swarts, Steven G.; Brookes, Paul S.; Gavin, Claire E. Gunter, Karlene K.

    2010-11-15

    Manganese (Mn) toxicity is partially mediated by reduced ATP production. We have used oxidation rate assays-a measure of ATP production-under rapid phosphorylation conditions to explore sites of Mn{sup 2+} inhibition of ATP production in isolated liver, brain, and heart mitochondria. This approach has several advantages. First, the target tissue for Mn toxicity in the basal ganglia is energetically active and should be studied under rapid phosphorylation conditions. Second, Mn may inhibit metabolic steps which do not affect ATP production rate. This approach allows identification of inhibitions that decrease this rate. Third, mitochondria from different tissues contain different amounts of the components of the metabolic pathways potentially resulting in different patterns of ATP inhibition. Our results indicate that Mn{sup 2+} inhibits ATP production with very different patterns in liver, brain, and heart mitochondria. The primary Mn{sup 2+} inhibition site in liver and heart mitochondria, but not in brain mitochondria, is the F{sub 1}F{sub 0} ATP synthase. In mitochondria fueled by either succinate or glutamate + malate, ATP production is much more strongly inhibited in brain than in liver or heart mitochondria; moreover, Mn{sup 2+} inhibits two independent sites in brain mitochondria. The primary site of Mn-induced inhibition of ATP production in brain mitochondria when succinate is substrate is either fumarase or complex II, while the likely site of the primary inhibition when glutamate plus malate are the substrates is either the glutamate/aspartate exchanger or aspartate aminotransferase.

  7. Study of soluble lipoprotein in rat liver mitochondria

    PubMed Central

    Koppikar, S. V.; Fatterpaker, P.; Sreenivasan, A.

    1971-01-01

    1. A water-soluble lipoprotein was isolated and purified from osmotically shocked preparations of rat liver mitochondria by using a technique of Sephadex-sandwich disc electrophoresis. 2. The purified lipoprotein migrates as a distinct sharp zone in high-resolution electrophoretic systems, indicating high degree of purity. 3. The lipoprotein resembles mitochondrial membranes with respect to lipid composition and lipid/protein ratio. 4. The lipoprotein and its apoprotein fraction obtained by delipidization at −18°C to −20°C have common properties with respect to their fluorescence spectra, instability to storage and electrophoretic mobility. 5. The purified lipoprotein has an excitation maximum at 325nm and a fluorescence maximum at 418nm. 6. Storage at 4°C for 4 days or repeated freezing and thawing results in 15–30% decrease in electrophoretic mobility. 7. The patterns of incorporation in vitro of [1-14C]leucine into proteins of the soluble lipoprotein and of mitochondrial membrane of isolated rat liver mitochondria suggest a probable precursor role for the apoprotein in the formation of mitochondrial membrane protein. 8. Lipoprotein preparations isolated from mitochondrial fractions of rat kidney, brain and heart and of chicken and mouse liver resemble closely that obtained from rat liver mitochondria, suggesting that the soluble lipoprotein could be a distinct entity of mitochondrial origin. ImagesFig. 4.Fig. 5. PMID:5114976

  8. Effect of the non-steroidal anti-inflammatory drugs on the acyl-CoA synthetase activity toward medium-chain, long-chain and polyunsaturated fatty acids in mitochondria of mouse liver and brain.

    PubMed

    Kasuya, Fumiyo; Kazuhiro, Misumi; Tatsuya, Hasegawa; Nakamoto, Kazuo; Tokuyama, Shogo; Masuyama, Teiichi

    2013-02-01

    Effect of eleven non-steroidal anti-inflammatory drugs on the acyl-CoA synthetase activities toward octanoic, palmitic, arachidonic and docosahexaenoic acids was evaluated in mouse liver and brain mitochondria. The drugs tested were aspirin, salicylic acid, diflunisal, mefenamic acid, indomethacin, etodolac, ibuprofen, ketoprofen, naproxen, loxoprofen, flurbiprofen. In mouse liver mitochondria, diflunisal and mefenamic acid exhibited the inhibitory activities not only for octanoic acid (IC(50) = 78.7 and 64.7 µM) and but also for palmitic acid (IC(50) = 236.5 and 284.4 µM), respectively. Aspirin was an inhibitor for the activation of octanoic acid only (IC(50) = 411.0 µM). In the brain, mefenamic acid and diflunisal inhibited strongly palmitoyl-CoA formation (IC(50) = 57.3 and 114.0 µM), respectively. The activation of docosahexaenoic acid in brain was sensitive to inhibition by diflunisal and mefenamic acid compared with liver. PMID:22299587

  9. Pathways for Ca2+ efflux in heart and liver mitochondria.

    PubMed Central

    Rizzuto, R; Bernardi, P; Favaron, M; Azzone, G F

    1987-01-01

    1. Two processes of Ruthenium Red-insensitive Ca2+ efflux exist in liver and in heart mitochondria: one Na+-independent, and another Na+-dependent. The processes attain maximal rates of 1.4 and 3.0 nmol of Ca2+.min-1.mg-1 for the Na+-dependent and 1.2 and 2.0 nmol of Ca2+.min-1.mg-1 for the Na+-independent, in liver and heart mitochondria, respectively. 2. The Na+-dependent pathway is inhibited, both in heart and in liver mitochondria, by the Ca2+ antagonist diltiazem with a Ki of 4 microM. The Na+-independent pathway is inhibited by diltiazem with a Ki of 250 microM in liver mitochondria, while it behaves as almost insensitive to diltiazem in heart mitochondria. 3. Stretching of the mitochondrial inner membrane in hypo-osmotic media results in activation of the Na+-independent pathway both in liver and in heart mitochondria. 4. Both in heart and liver mitochondria the Na+-independent pathway is insensitive to variations of medium pH around physiological values, while the Na+-dependent pathway is markedly stimulated parallel with acidification of the medium. The pH-activated, Na+-dependent pathway maintains the diltiazem sensitivity. 5. In heart mitochondria, the Na+-dependent pathway is non-competitively inhibited by Mg2+ with a Ki of 0.27 mM, while the Na+-independent pathway is less affected; similarly, in liver mitochondria Mg2+ inhibits the Na+-dependent pathway more than it does the Na+-independent pathway. In the presence of physiological concentrations of Na+, Ca2+ and Mg2+, the Na+-independent and the Na+-dependent pathways operate at rates, respectively, of 0.5 and 1.0 nmol of Ca2+.min-1.mg-1 in heart mitochondria and 0.9 and 0.2 nmol of Ca2+.min-1.mg-1 in liver mitochondria. It is concluded that both heart and liver mitochondria possess two independent pathways for Ca2+ efflux operating at comparable rates. PMID:3689311

  10. Metabolic compensations in mitochondria isolated from the heart, liver, kidney, brain and white muscle in the southern catfish (Silurus meridionalis) by seasonal acclimation.

    PubMed

    Yan, Yulian; Xie, Xiaojun

    2015-05-01

    In order to examine the effects of seasonal acclimation on mitochondrial metabolic functions and test tissue-specific pattern of the metabolic compensation within individuals of the southern catfish (Silurus meridionalis Chen), rates of mitochondrial respiration and activities of cytochrome c oxidase (COX) in the heart, liver, kidney, brain and white muscle of this fish in the summer-acclimatized group (153.20±1.66 g) and winter-acclimatized group (177.71±3.04 g) were measured at seven assay temperatures (7.5, 12.5, 17.5, 22.5, 27.5, 32.5 and 37.5°C), respectively. The results show that compensatory adjustments in state III respiratory rate and COX activity occur significantly in the heart, kidney and liver, but do not in the brain and white muscle, which suggest that the metabolic compensation of this fish in response to seasonal acclimation exhibits a tissue-specific pattern. The cold acclimation increases mitochondrial oxidative capacities in the heart, kidney and liver concomitantly with reducing their upper thermal limits of mitochondrial functions at acute warming and the thermal tolerance shifts in the same tissue-specific pattern as the metabolic compensation. When combining the effects of seasonal acclimation on mitochondrial oxidative capacity and organ mass, the metabolic compensation demonstrates an organ-specific pattern with four categories: over-compensation in the heart, complete compensation in the kidney, partial compensation in the liver and no compensation in the brain. The organ-specific pattern of metabolic compensation might be a trade-off strategy of the performance adjustments in the seasonal acclimation for this fish to maximize its fitness. PMID:25498350

  11. Metabolism of deoxypyrimidines and deoxypyrimidine antiviral analogs in isolated brain mitochondria

    PubMed Central

    McCann, Kathleen A.; Williams, David W.; McKee, Edward E.

    2012-01-01

    The goal of this project was to characterize deoxypyrimidine salvage pathways used to maintain deoxynucleoside triphosphate pools in isolated brain mitochondria and to determine the extent that antiviral pyrimidine analogs utilize or affect these pathways. Mitochondria from rat brains were incubated in media with labeled and unlabeled deoxynucleosides and deoxynucleoside analogs. Products were analyzed by HPLC coupled to an inline UV monitor and liquid scintillation counter. Isolated mitochondria transported thymidine and deoxycytidine into the matrix, and readily phosphorylated both of these to mono-, di, and tri-phosphate nucleotides. Rates of phosphorylation were much higher than rates observed in mitochondria from heart and liver. Deoxyuridine was phosphorylated much more slowly than thymidine and only to dUMP. AZT, an antiviral thymidine analog, was phosphorylated to AZT-MP as readily as thymidine was phosphorylated to TMP, but little if any AZT-DP or AZT-TP was observed. AZT at 5.5 ± 1.7 μM was shown to inhibit thymidine phosphorylation by 50%, but was not observed to inhibit deoxycytidine phosphorylation except at levels > 100 μM. Stavudine and lamivudine were inert when incubated with isolated brain mitochondria. The kinetics of phosphorylation of thymidine, dC and AZT were significantly different in brain mitochondria compared to mitochondria from liver and heart. PMID:22530558

  12. Zinc metallothionein imported into liver mitochondria modulates respiration

    PubMed Central

    Ye, Bin; Maret, Wolfgang; Vallee, Bert L.

    2001-01-01

    Metallothionein (MT) localizes in the intermembrane space of liver mitochondria as well as in the cytosol and nucleus. Incubation of intact liver mitochondria with physiological, micromolar concentrations of MT leads to the import of MT into the mitochondria where it inhibits respiration. This activity is caused by the N-terminal β-domain of MT; in this system, the isolated C-terminal α-domain is inactive. Free zinc inhibits respiration at concentrations commensurate with the zinc content of either MT or the isolated β-domain, indicating that MT inhibition involves zinc delivery to mitochondria. Respiratory inhibition of uncoupled mitochondria identifies the electron transfer chain as the primary site of inhibition. The apoform of MT, thionein, is an endogenous chelating agent and activates zinc-inhibited respiration with a 1:1 stoichiometry ([zinc binding sites]/[zinc]). Carbamoylation of the lysines of MT significantly attenuates the inhibitory effect, suggesting that these residues are critical for the passage of MT through the outer mitochondrial membrane. Such an import pathway has been proposed for other proteins that also lack a mitochondrial targeting sequence, e.g., apocytochrome c, and possibly Cox17, a mitochondrial copper chaperone that is the only protein known so far to exhibit significant primary sequence homology to MT. The presence and respiratory inhibition of MT in liver, but not heart, mitochondria suggest a hitherto unknown biological modulating activity of MT in cellular respiration and energy metabolism in a tissue-specific manner. PMID:11226237

  13. The riboflavin/FAD cycle in rat liver mitochondria.

    PubMed

    Barile, M; Brizio, C; Valenti, D; De Virgilio, C; Passarella, S

    2000-08-01

    Here we provide evidence that mitochondria isolated from rat liver can synthesize FAD from riboflavin that has been taken up and from endogenous ATP. Riboflavin uptake takes place via a carrier-mediated process, as shown by the inverse relationship between fold accumulation and riboflavin concentration, the saturation kinetics [riboflavin Km and Vmax values were 4.4+/-1.3 microM and 35+/-5 pmol x min(-1) (mg protein)(-1), respectively] and the inhibition shown by the thiol reagent mersalyl, which cannot enter the mitochondria. FAD synthesis is due to the existence of FAD synthetase (EC 2.7.7.2), localized in the matrix, which has as a substrate pair mitochondrial ATP and FMN synthesized from taken up riboflavin via the putative mitochondrial riboflavin kinase. In the light of certain features, including the protein thermal stability and molecular mass, mitochondrial FAD synthetase differs from the cytosolic isoenzyme. Apparent Km and apparent Vmax values for FMN were 5.4+/-0.9 microM and 22.9+/-1.4 pmol x min(-1) x (mg matrix protein)(-1), respectively. Newly synthesized FAD inside the mitochondria can be exported from the mitochondria in a manner sensitive to atractyloside but insensitive to mersalyl. The occurrence of the riboflavin/FAD cycle is proposed to account for riboflavin uptake in mitochondria biogenesis and riboflavin recovery in mitochondrial flavoprotein degradation; both are prerequisites for the synthesis of mitochondrial flavin cofactors. PMID:10903524

  14. Systems proteomics of liver mitochondria function.

    PubMed

    Williams, Evan G; Wu, Yibo; Jha, Pooja; Dubuis, Sébastien; Blattmann, Peter; Argmann, Carmen A; Houten, Sander M; Amariuta, Tiffany; Wolski, Witold; Zamboni, Nicola; Aebersold, Ruedi; Auwerx, Johan

    2016-06-10

    Recent improvements in quantitative proteomics approaches, including Sequential Window Acquisition of all Theoretical Mass Spectra (SWATH-MS), permit reproducible large-scale protein measurements across diverse cohorts. Together with genomics, transcriptomics, and other technologies, transomic data sets can be generated that permit detailed analyses across broad molecular interaction networks. Here, we examine mitochondrial links to liver metabolism through the genome, transcriptome, proteome, and metabolome of 386 individuals in the BXD mouse reference population. Several links were validated between genetic variants toward transcripts, proteins, metabolites, and phenotypes. Among these, sequence variants in Cox7a2l alter its protein's activity, which in turn leads to downstream differences in mitochondrial supercomplex formation. This data set demonstrates that the proteome can now be quantified comprehensively, serving as a key complement to transcriptomics, genomics, and metabolomics--a combination moving us forward in complex trait analysis. PMID:27284200

  15. Mitochondria: the gateway for tamoxifen-induced liver injury.

    PubMed

    Ribeiro, Mariana P C; Santos, Armanda E; Custódio, José B A

    2014-09-01

    Tamoxifen (TAM) is routinely used in the treatment of breast carcinoma. TAM-induced liver injury remains a major concern, as TAM causes hepatic steatosis in a significant number of patients, which can progress toward steatohepatitis. Liver toxicity is generally believed to involve mitochondrial dysfunction and TAM exerts multiple deleterious effects on mitochondria, which may account for the hepatotoxicity observed in patients treated with TAM. Endoxifen (EDX), a key active metabolite of TAM that is being investigated as an alternative to TAM in breast cancer therapy, slightly affects mitochondria in comparison with TAM and this demonstration well correlates with the absence of alterations in the clinical parameters of individuals taking EDX. The steady-state plasma concentrations of TAM and its active metabolites EDX and 4-hydroxytamoxifen (OHTAM) in patients taking TAM are highly variable, reflecting genetic variants of CYP2D6 involved in TAM metabolism. Besides de genetic polymorphisms, the intake of drugs that influence the enzymatic activity of CYP2D6 compromises the therapeutic efficiency of TAM. The knowledge of the impact of the variability of TAM metabolism in the breast cancer treatment explains the discrepant outcomes observed in patients taking TAM, as well as the individual variability of idiosyncratic liver injury and other sides effects observed. Therefore, and contrarily to the clinical use of EDX, the need of therapeutic drug monitoring and a regular assessment of liver function biomarkers should be considered in patients under therapies with TAM. In this review we focus on the mitochondrial effects of TAM and its metabolites and on the role played by mitochondria in the initiating events leading to TAM-induced hepatotoxicity, as well as the clinical implications. PMID:24881593

  16. D-Lactate transport and metabolism in rat liver mitochondria.

    PubMed Central

    de Bari, Lidia; Atlante, Anna; Guaragnella, Nicoletta; Principato, Giovanni; Passarella, Salvatore

    2002-01-01

    In the present study we investigated whether isolated rat liver mitochondria can take up and metabolize D-lactate. We found the following: (1) externally added D-lactate causes oxygen uptake by mitochondria [P/O ratio (the ratio of mol of ATP synthesized to mol of oxygen atoms reduced to water during oxidative phosphorylation)=2] and membrane potential (Delta(psi)) generation in processes that are rotenone-insensitive, but inhibited by antimycin A and cyanide, and proton release from coupled mitochondria inhibited by alpha-cyanocinnamate, but not by phenylsuccinate; (2) the activity of the putative flavoprotein (D-lactate dehydrogenase) was detected in inside-out submitochondrial particles, but not in mitochondria and mitoplasts, as it is localized in the matrix phase of the mitochondrial inner membrane; (3) three novel separate translocators exist to mediate D-lactate traffic across the mitochondrial inner membrane: the D-lactate/H(+) symporter, which was investigated by measuring fluorimetrically the rate of endogenous flavin reduction, the D-lactate/oxoacid antiporter (which mediates both the D-lactate/pyruvate and D-lactate/oxaloacetate exchanges) and D-lactate/malate antiporter studied by monitoring photometrically the appearance of the D-lactate counteranions outside mitochondria. The D-lactate translocators, in the light of their different inhibition profiles separate from the monocarboxylate carrier, were found to differ from each other in the V(max) values and in the inhibition and pH profiles and were shown to regulate mitochondrial D-lactate metabolism in vitro. The D-lactate translocators and the D-lactate dehydrogenase could account for the removal of the toxic methylglyoxal from cytosol, as well as for D-lactate-dependent gluconeogenesis. PMID:11955284

  17. Glycyrrhetinic acid-induced permeability transition in rat liver mitochondria.

    PubMed

    Salvi, Mauro; Fiore, Cristina; Armanini, Decio; Toninello, Antonio

    2003-12-15

    Glycyrrhetinic acid, a hydrolysis product of one of the main constituents of licorice, the triterpene glycoside of glycyrrhizic acid, when added to rat liver mitochondria at micromolar concentrations induces swelling, loss of membrane potential, pyridine nucleotide oxidation, and release of cytochrome c and apoptosis inducing factor. These changes are Ca(2+) dependent and are prevented by cyclosporin A, bongkrekic acid, and N-ethylmaleimide. All these observations indicate that glycyrrhetinic acid is a potent inducer of mitochondrial permeability transition and can trigger the pro-apoptotic pathway. PMID:14637195

  18. Some properties of aldehyde dehydrogenase from sheep liver mitochondria.

    PubMed Central

    Hart, G J; Dickinson, F M

    1977-01-01

    Aldehyde dehydrogenase from sheep liver mitochondria was purified to homogeneity as judged by electrophoresis on polyacrylamide gels, and by sedimentation-equilibrium experiments in the analytical ultracentrifuge. The enzyme has a molecular weight of 198000 and a subunit size of 48000, indicating that the molecule is a tetramer. Fluorescence and spectrophotometric titrations indicate that each subunit can bind 1 molecule of NADH. Enzymic activity is completely blocked by reaction of 4mol of 5,5'-dithiobis-(2-nitrobenzoate)/mol of enzyme. Excess of disulfiram or iodoacetamide decreases activity to only 50% of the control value, and only two thiol groups per molecule are apparently modified by these reagents. PMID:194582

  19. Fractionation of human liver mitochondria: enzymic and morphological characterization of the inner and outer membranes as compared to rat liver mitochondria.

    PubMed

    Benga, G; Hodarnau, A; Tilinca, R; Porutiu, D; Dancea, S; Pop, V; Wrigglesworth, J

    1979-02-01

    The fractionation of human liver mitochondria into inner membrane, outer membrane and matrix material is reported. Compared with rat, human liver mitochondria are more fragile. Fractionation can be achieved in only 2 steps, a digitonin treatment for removal of the outer membrane and centrifugation of the inner membrane plus matrix particles through a linear sucrose gradient resulting in purified inner membranes and matrix. PMID:422680

  20. Effects of Stevia rebaudiana natural products on rat liver mitochondria.

    PubMed

    Kelmer Bracht, A; Alvarez, M; Bracht, A

    1985-03-15

    The effects of several natural products extracted from the leaves of Stevia rebaudiana on rat liver mitochondria were investigated. The compounds used were stevioside (a non-caloric sweetener), steviolbioside, isosteviol and steviol. Total aqueous extracts of the leaves were also investigated. S. rebaudiana natural products inhibited oxidative phosphorylation, ATPase activity NADH-oxidase activity, succinate-oxidase activity, succinate dehydrogenase, and L-glutamate dehydrogenase. The ADP/O ratio was decreased. Substrate respiration (state II respiration) was increased at low concentrations (up to 0.5 mM) and inhibited at higher concentrations (1 mM or more). In uncoupled mitochondria, inhibition of substrate respiration was the only effect observed. Net proton ejection induced by succinate and swelling induced by several substrates were inhibited. Of the compounds investigated, the sweet principle stevioside was less active. It was concluded that, in addition to the inhibitory effects, S. rebaudiana natural products may also act as uncouplers of oxidative phosphorylation. The possible physiologic consequences of the ingestion of stevioside and S. rebaudiana aqueous extracts are discussed. PMID:2858211

  1. Role of Mitochondria in Nonalcoholic Fatty Liver Disease

    PubMed Central

    Nassir, Fatiha; Ibdah, Jamal A.

    2014-01-01

    Nonalcoholic fatty liver disease (NAFLD) affects about 30% of the general population in the United States and includes a spectrum of disease that includes simple steatosis, non-alcoholic steatohepatitis (NASH), fibrosis and cirrhosis. Significant insight has been gained into our understanding of the pathogenesis of NALFD; however the key metabolic aberrations underlying lipid accumulation in hepatocytes and the progression of NAFLD remain to be elucidated. Accumulating and emerging evidence indicate that hepatic mitochondria play a critical role in the development and pathogenesis of steatosis and NAFLD. Here, we review studies that document a link between the pathogenesis of NAFLD and hepatic mitochondrial dysfunction with particular focus on new insights into the role of impaired fatty acid oxidation, the transcription factor peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α), and sirtuins in development and progression of NAFLD. PMID:24837835

  2. Selective permeability of rat liver mitochondria to purified aspartate aminotransferases in vitro.

    PubMed Central

    Marra, E; Doonan, S; Saccone, C; Quagliariello, E

    1977-01-01

    1. A method was devised to allow determination of intramitochondrial aspartate amino-transferase activity in suspensions of intact mitochondria. 2. Addition of purified rat liver mitochondrial aspartate aminotransferase to suspensions of rat liver mitochondria caused an apparent increase in the intramitochondrial enzyme activity. No increase was observed when the mitochondria were preincubated with the purified cytoplasmic isoenzyme. 3. These results suggest that mitochondrial aspartate aminotransferase, but not the cytoplasmic isoenzyme, is able to pass from solution into the matrix of intact rat liver mitochondria in vitro. 4. This system may provide a model for studies of the little-understood processes by which cytoplasmically synthesized components are incorporated into mitochondria in vivo. PMID:883959

  3. Proton conductance and fatty acyl composition of liver mitochondria correlates with body mass in birds.

    PubMed Central

    Brand, Martin D; Turner, Nigel; Ocloo, Augustine; Else, Paul L; Hulbert, A J

    2003-01-01

    The proton conductance of isolated liver mitochondria correlates significantly with body mass in mammals, but not in ectotherms. To establish whether the correlation in mammals is general for endotherms or mammal-specific, we measured proton conductance in mitochondria from birds, the other main group of endotherms, using birds varying in mass over a wide range (nearly 3000-fold), from 13 g zebra finches to 35 kg emus. Respiratory control ratios were higher in mitochondria from larger birds. Mitochondrial proton conductance in liver mitochondria from birds correlated strongly with body mass [respiration rate per mg of protein driving proton leak at 170 mV being 44.7 times (body mass in g)(-0.19)], thus suggesting a general relationship between body mass and proton conductance in endotherms. Mitochondria from larger birds had the same or perhaps greater surface area per mg of protein than mitochondria from smaller birds. Hence, the lower proton conductance was caused not by surface area changes but by some change in the properties of the inner membrane. Liver mitochondria from larger birds had phospholipid fatty acyl chains that were less polyunsaturated and more monounsaturated when compared with those from smaller birds. Phospholipid fatty acyl polyunsaturation correlated positively and monounsaturation correlated negatively with proton conductance. These correlations echo those seen in mammalian liver mitochondria, suggesting that they too are general for endotherms. PMID:12943530

  4. The energy blockers 3-bromopyruvate and lonidamine: effects on bioenergetics of brain mitochondria.

    PubMed

    Macchioni, Lara; Davidescu, Magdalena; Roberti, Rita; Corazzi, Lanfranco

    2014-10-01

    Tumor cells favor abnormal energy production via aerobic glycolysis and show resistance to apoptosis, suggesting the involvement of mitochondrial dysfunction. The differences between normal and cancer cells in their energy metabolism provide a biochemical basis for developing new therapeutic strategies. The energy blocker 3-bromopyruvate (3BP) can eradicate liver cancer in animals without associated toxicity, and is a potent anticancer towards glioblastoma cells. Since mitochondria are 3BP targets, in this work the effects of 3BP on the bioenergetics of normal rat brain mitochondria were investigated in vitro, in comparison with the anticancer agent lonidamine (LND). Whereas LND impaired oxygen consumption dependent on any complex of the respiratory chain, 3BP was inhibitory to malate/pyruvate and succinate (Complexes I and II), but preserved respiration from glycerol-3-phosphate and ascorbate (Complex IV). Accordingly, although electron flow along the respiratory chain and ATP levels were decreased by 3BP in malate/pyruvate- and succinate-fed mitochondria, they were not significantly influenced from glycerol-3-phosphate- or ascorbate-fed mitochondria. LND produced a decrease in electron flow from all substrates tested. No ROS were produced from any substrate, with the exception of 3BP-induced H(2)O(2) release from succinate, which suggests an antimycin-like action of 3BP as an inhibitor of Complex III. We can conclude that 3BP does not abolish completely respiration and ATP synthesis in brain mitochondria, and has a limited effect on ROS production, confirming that this drug may have limited harmful effects on normal cells. PMID:25194986

  5. Role of Mitochondria in Neonatal Hypoxic-Ischemic Brain Injury

    PubMed Central

    Lu, Yujiao; Tucker, Donovan; Dong, Yan; Zhao, Ningjun; Zhuo, Xiaoying; Zhang, Quanguang

    2016-01-01

    Hypoxic-ischemia (HI) causes severe brain injury in neonates. It’s one of the leading causes to neonatal death and pediatric disability, resulting in devastating consequences, emotionally and economically, to their families. A series of events happens in this process, e.g. excitatory transmitter release, extracelluar Ca2+ influxing, mitochondrial dysfunction, energy failure, and neuron death. There are two forms of neuron death after HI insult: necrosis and apoptosis, apoptosis being the more prevalent form. Mitochondria handle a series of oxidative reactions, and yield energy for various cellular activities including the maintainance of membrane potential and preservation of intracellular ionic homeostasis. Therefore mitochondria play a critical role in neonatal neurodegeneration following HI, and mitochondrial dysfunction is the key point in neurodegenerative evolution. Because of this, exploring effective mitochondria-based clinical strategies is crucial. Today the only efficacious clinic treatment is hypothermia. However, due to its complex management, clinical complication and autoimmune decrease, its clinical application is limited. So far, many mitochondria-based strategies have been reported neuroprotective in animal models, which offers promise on neonatal therapy. However, since their clinical effectiveness are still unclear, plenty of studies need to be continued in the future. According to recent reports, two novel strategies have been proposed: methylene blue (MB) and melatonin. Although they are still in primary stage, the underlying mechanisms indicate promising clinical applications. Every neurological therapeutic strategy has its intrinsic deficit and limited efficacy, therefore in the long run, the perfect clinical therapy for hypoxic-ischemic neonatal brain injury will be based on the combination of multiple strategies. PMID:27441209

  6. Calcium signaling in brain mitochondria: interplay of malate aspartate NADH shuttle and calcium uniporter/mitochondrial dehydrogenase pathways.

    PubMed

    Contreras, Laura; Satrústegui, Jorgina

    2009-03-13

    Ca2+ signaling in mitochondria has been mainly attributed to Ca2+ entry to the matrix through the Ca2+ uniporter and activation of mitochondrial matrix dehydrogenases. However, mitochondria can also sense increases in cytosolic Ca2+ through a mechanism that involves the aspartate-glutamate carriers, extramitochondrial Ca2+ activation of the NADH malate-aspartate shuttle (MAS). Both pathways are linked through the shared substrate alpha-ketoglutarate (alphaKG). Here we have studied the interplay between the two pathways under conditions of Ca2+ activation. We show that alphaKG becomes limiting when Ca2+ enters in brain or heart mitochondria, but not liver mitochondria, resulting in a drop in alphaKG efflux through the oxoglutarate carrier and in a drop in MAS activity. Inhibition of alphaKG efflux and MAS activity by matrix Ca2+ in brain mitochondria was fully reversible upon Ca2+ efflux. Because of their differences in cytosolic calcium concentration requirements, the MAS and Ca2+ uniporter-mitochondrial dehydrogenase pathways are probably sequentially activated during a Ca2+ transient, and the inhibition of MAS at the center of the transient may provide an explanation for part of the increase in lactate observed in the stimulated brain in vivo. PMID:19129175

  7. Metabolism of propionate by sheep-liver mitochondria

    PubMed Central

    Smith, R. M.; Russell, G. R.

    1967-01-01

    1. Metabolism of propionate by sheep-liver mitochondria was stimulated catalytically by α-oxoglutarate, pyruvate, citrate and isocitrate. Succinate was stimulatory at higher concentrations, but fumarate and malate were inert. These effects were all independent of the presence of ATP, succinate being less effective when ATP was present. 2. Compared with the metabolism of added succinate, propionate metabolism was resistant to malonate inhibition, but only in the presence of added ATP. In the absence of ATP propionate metabolism was more sensitive to malonate inhibition than was the metabolism of succinate. 3. In the absence of malonate, and at malonate concentrations in the range 5–100mm, α-oxoglutarate increased the rate of fixation of [2-14C]propionate by about 50% without altering the nature of the fixation products. 4. Metabolism of [1-14C]-propionate in the presence of 50mm-malonate was accompanied by accumulation of about half the propionate consumed as succinate. When α-oxoglutarate was present in addition part of the α-oxoglutarate was metabolized and the rate of propionate consumption was increased. The total succinate that accumulated corresponded to the α-oxoglutarate consumed plus about half the propionate metabolized. 5. When [1-14C]propionate was metabolized in the absence of malonate about 70% of the generated succinate was oxidized to fumarate or beyond. The addition of malonate decreased the rate of propionate metabolism, and decreased to about half the fraction of generated succinate oxidized. 6. When propionate and 10mm-succinate were metabolized together, the total oxidation of succinate was greater than that with 10mm-succinate alone. The increment in succinate oxidation corresponded to about half the propionate metabolized in the presence or absence of malonate or ATP. 7. It is suggested that the metabolism of propionate is specifically limited by the rate of oxidation of the generated succinate, and that the succinate oxidase concerned

  8. Mitochondria-controlled signaling mechanisms of brain protection in hypoxia

    PubMed Central

    Lukyanova, Ludmila D.; Kirova, Yulia I.

    2015-01-01

    The article is focused on the role of the cell bioenergetic apparatus, mitochondria, involved in development of immediate and delayed molecular mechanisms for adaptation to hypoxic stress in brain cortex. Hypoxia induces reprogramming of respiratory chain function and switching from oxidation of NAD-related substrates (complex I) to succinate oxidation (complex II). Transient, reversible, compensatory activation of respiratory chain complex II is a major mechanism of immediate adaptation to hypoxia necessary for (1) succinate-related energy synthesis in the conditions of oxygen deficiency and formation of urgent resistance in the body; (2) succinate-related stabilization of HIF-1α and initiation of its transcriptional activity related with formation of long-term adaptation; (3) succinate-related activation of the succinate-specific receptor, GPR91. This mechanism participates in at least four critical regulatory functions: (1) sensor function related with changes in kinetic properties of complex I and complex II in response to a gradual decrease in ambient oxygen concentration; this function is designed for selection of the most efficient pathway for energy substrate oxidation in hypoxia; (2) compensatory function focused on formation of immediate adaptive responses to hypoxia and hypoxic resistance of the body; (3) transcriptional function focused on activated synthesis of HIF-1 and the genes providing long-term adaptation to low pO2; (4) receptor function, which reflects participation of mitochondria in the intercellular signaling system via the succinate-dependent receptor, GPR91. In all cases, the desired result is achieved by activation of the succinate-dependent oxidation pathway, which allows considering succinate as a signaling molecule. Patterns of mitochondria-controlled activation of GPR-91- and HIF-1-dependent reaction were considered, and a possibility of their participation in cellular-intercellular-systemic interactions in hypoxia and adaptation was

  9. Cannabinoid-induced changes in respiration of brain mitochondria.

    PubMed

    Fišar, Zdeněk; Singh, Namrata; Hroudová, Jana

    2014-11-18

    Cannabinoids exert various biological effects that are either receptor-mediated or independent of receptor signaling. Mitochondrial effects of cannabinoids were interpreted either as non-receptor-mediated alteration of mitochondrial membranes, or as indirect consequences of activation of plasma membrane type 1 cannabinoid receptors (CB1). Recently, CB1 receptors were confirmed to be localized to the membranes of neuronal mitochondria, where their activation directly regulates respiration and energy production. Here, we performed in-depth analysis of cannabinoid-induced changes of mitochondrial respiration using both an antagonist/inverse agonist of CB1 receptors, AM251 and the cannabinoid receptor agonists, Δ(9)-tetrahydrocannabinol (THC), cannabidiol, anandamide, and WIN 55,212-2. Relationships were determined between cannabinoid concentration and respiratory rate driven by substrates of complex I, II or IV in pig brain mitochondria. Either full or partial inhibition of respiratory rate was found for the tested drugs, with an IC50 in the micromolar range, which verified the significant role of non-receptor-mediated mechanism in inhibiting mitochondrial respiration. Effect of stepwise application of THC and AM251 evidenced protective role of AM251 and corroborated the participation of CB1 receptor activation in the inhibition of mitochondrial respiration. We proposed a model, which includes both receptor- and non-receptor-mediated mechanisms of cannabinoid action on mitochondrial respiration. This model explains both the inhibitory effect of cannabinoids and the protective effect of the CB1 receptor inverse agonist. PMID:25195527

  10. Lipid peroxidation in brain or spinal cord mitochondria after injury.

    PubMed

    Hall, Edward D; Wang, Juan A; Bosken, Jeffrey M; Singh, Indrapal N

    2016-04-01

    Extensive evidence has demonstrated an important role of oxygen radical formation (i.e., oxidative stress) as a mediator of the secondary injury process that occurs following primary mechanical injury to the brain or spinal cord. The predominant form of oxygen radical-induced oxidative damage that occurs in injured nervous tissue is lipid peroxidation (LP). Much of the oxidative stress in injured nerve cells initially begins in mitochondria via the generation of the reactive nitrogen species peroxynitrite (PN) which then can generate multiple highly reactive free radicals including nitrogen dioxide (•NO2), hydroxyl radical (•OH) and carbonate radical (•CO3). Each can readily induce LP within the phospholipid membranes of the mitochondrion leading to respiratory dysfunction, calcium buffering impairment, mitochondrial permeability transition and cell death. Validation of the role of LP in central nervous system secondary injury has been provided by the mitochondrial and neuroprotective effects of multiple antioxidant agents which are briefly reviewed. PMID:25595872

  11. Kinetics and control of oxidative phosphorylation in rat liver mitochondria after dexamethasone treatment

    PubMed Central

    2004-01-01

    The present investigation was undertaken in order to evaluate the contributions of ATP synthesis and proton leak reactions to the rate of active respiration of liver mitochondria, which is altered following dexamethasone treatment (1.5 mg/kg per day for 5 days). We applied top-down metabolic control analysis and its extension, elasticity analysis, to gain insight into the mechanisms of glucocorticoid regulation of mitochondrial bioenergetics. Liver mitochondria were isolated from dexamethasone-treated, pair-fed and control rats when in a fed or overnight fasted state. Injection of dexamethasone for 5 days resulted in an increase in the fraction of the proton cycle of phosphorylating liver mitochondria, which was associated with a decrease in the efficiency of the mitochondrial oxidative phosphorylation process in liver. This increase in proton leak activity occurred with little change in the mitochondrial membrane potential, despite a significant decrease in the rate of oxidative phosphorylation. Regulation analysis indicates that mitochondrial membrane potential homoeostasis is achieved by equal inhibition of the mitochondrial substrate oxidation and phosphorylation reactions in rats given dexamethasone. Our results also suggest that active liver mitochondria from dexamethasone-treated rats are capable of maintaining phosphorylation flux for cellular purposes, despite an increase in the energetic cost of mitochondrial ATP production due to increased basal proton permeability of the inner membrane. They also provide a complete description of the effects of dexamethasone treatment on liver mitochondrial bioenergetics. PMID:15175015

  12. An assessment of the calcium content of rat liver mitochondria in vivo.

    PubMed Central

    Reinhart, P H; van de Pol, E; Taylor, W M; Bygrave, F L

    1984-01-01

    The effect of systematically altering the isolation conditions on the total calcium content of mitochondria isolated from perfused rat liver was examined. We showed that, under most isolation conditions, significant redistributions of mitochondrial calcium occurred resulting in up to 5-fold changes of the total calcium content. Mitochondrial Ca2+ flux inhibitors such as Ruthenium Red and nupercaine were only partially effective in inhibiting such redistributions. We present evidence indicating that the total calcium content of rat liver mitochondria in situ may approximate 2 nmol X (mg of protein)-1. PMID:6201164

  13. Ultrastructural aspects and amino acid composition of the purified inner and outer membranes of human liver mitochondria as compared to rat liver mitochondria.

    PubMed

    Benga, G; Poruţiu, D; Hodârnău, A; Ferdinand, W

    1992-05-01

    1. The mitochondria isolated from human or rat liver were fractionated into submitochondrial particles and purified inner and outer membrane. According to different marker enzymes the inner membranes were enriched about 5-6-fold and the outer membranes about 12-14-fold. The electron microscopical appearance of the membranes was that expected on the basis of enzymic characterization. 2. A comparison of the average amino acid composition of the membrane proteins from the two types of mitochondria has been made. In the case of submitochondrial particles there were statistically significant differences between the human and rat hydrolysates for only five amino acids. Analysing the purified mitochondrial membranes there were significant differences between the two species for nine amino acids in the case of outer membranes and for 12 amino acids in the case of inner membranes. 3. With one exception all amino acids that were increased or decreased in the outer membrane exhibited a similar trend in the inner membrane of human compared with rat liver mitochondria. It appears that liver mitochondrial membranes have a species-dependent pattern of amino acid composition of their proteins. PMID:1526116

  14. [Age-related Peculiarities of Succinate Effect on Induced Lipid Peroxidation in Rat Liver Mitochondria].

    PubMed

    Grishina, E V; Khaustova, Ya V; Vasilieva, A A; Mayevsky, E I

    2015-01-01

    The antioxidant effect of succinate and 3-hydroxybutyrate oxidation on the kinetics of lipid peroxidation induced by ATP-Fe2+ complex in isolated rat liver mitochondria of old (1.0-1.5 years) and young (3 months) male rats was investigated. The rate of induced lipid peroxidation V(LPO) in rat liver mitochondria and the half-time of oxygen consumption Δt50, which included the lag period and the initiation. phase, was recorded polarographically. Without exogenous oxidative-substrates V(LPO) was slightly higher in mitochondria of old animals, but the onset of lipid peroxidation cascade was significantly earlier than in young animals. Incubation of mitochondria with 5mM succinate for 1 min inhibited V(LPO) by 15% in young animals and by 35% in old animals. However, only in mitochondria of old animals Δt50 increased by 19% as compared to lipid peroxidation without substrates. V(LPO) in mitochondria of young animals did not significantly change during 3-hydroxybutyrate oxidation, while in mitochondria of old animals it was reduced by 19% with a slight increase in Δt50. To simulate age-dependent dysfunction we damaged isolated mitochondria by a series of freeze-thaw cycles, which caused a significant increase of V(LPO) of.both age groups. Succinate oxidation inhibited V(LPO) in damaged mitochondria in all cases by 56%, as compared to V(LPO) without oxidative substrates and extended At50 twofold in mitochondria of young animals. Oxidation of 3-hydroxybutyrate had no effect on V(LPO) in damaged mitochondria regardless of animal, age and extended Δt50 by 48% in mitochondria of young animals. Thus, the antioxidant effect of succinate oxidation can prevent lipid peroxidation damage and may exhibit geroprotective action at the level of aging mitochondria. Therefore, the antioxidant effect is due to the process of substrate oxidation in the respiratory chain but not because of an interaction of their structures with membrane lipids per se. PMID:26394470

  15. Arsenic induces apoptosis in mouse liver is mitochondria dependent and is abrogated by N-acetylcysteine

    SciTech Connect

    Santra, Amal . E-mail: asantra2000@yahoo.co.in; Chowdhury, Abhijit; Ghatak, Subhadip; Biswas, Ayan; Dhali, Gopal Krishna

    2007-04-15

    Arsenicosis, caused by arsenic contamination of drinking water supplies, is a major public health problem in India and Bangladesh. Chronic liver disease, often with portal hypertension occurs in chronic arsenicosis, contributes to the morbidity and mortality. The early cellular events that initiate liver cell injury due to arsenicosis have not been studied. Our aim was to identify the possible mechanisms related to arsenic-induced liver injury in mice. Liver injury was induced in mice by arsenic treatment. The liver was used for mitochondrial oxidative stress, mitochondrial permeability transition (MPT). Evidence of apoptosis was sought by TUNEL test, caspase assay and histology. Pretreatment with N-acetyl-L-cysteine (NAC) was done to modulate hepatic GSH level. Arsenic treatment in mice caused liver injury associated with increased oxidative stress in liver mitochondria and alteration of MPT. Altered MPT facilitated cytochrome c release in the cytosol, activation of caspase 9 and caspase 3 activities and apoptotic cell death. Pretreatment of NAC to arsenic-treated mice abrogated all these alteration suggesting a glutathione (GSH)-dependent mechanism. Oxidative stress in mitochondria and inappropriate MPT are important in the pathogenesis of arsenic induced apoptotic liver cell injury. The phenomenon is GSH dependent and supplementation of NAC might have beneficial effects.

  16. Inhibition of nucleoside diphosphate kinase in rat liver mitochondria by added 3'-azido-3'-deoxythymidine.

    PubMed

    Valenti, D; Barile, M; Quagliariello, E; Passarella, S

    1999-02-12

    The effect of 3'-azido-3'-deoxythymidine on nucleoside diphosphate kinase of isolated rat liver mitochondria has been studied. This is done by monitoring the increase in the rate of oxygen uptake by nucleoside diphosphate (TDP, UDP, CDP or GDP) addition to mitochondria in state 4. It is shown that 3'-azido-3'-deoxythymidine inhibits the mitochondrial nucleoside diphosphate kinase in a competitive manner, with a Ki value of about 10 microM as measured for each tested nucleoside diphosphate. It is also shown that high concentrations of GDP prevent 3'-azido-3'-deoxythymidine inhibition of the nucleoside diphosphate kinase. PMID:10050777

  17. Studies on the nature of the high-affinity trialkyltin binding site of rat liver mitochondria.

    PubMed Central

    Dawson, A P; Farrow, B G; Selwyn, M J

    1982-01-01

    1. The proteolipid fraction isolated from rat liver mitochondria pretreated with [3H]triphenyltin chloride is enriched in triphenyltin compared with the original mitochondria. 2. Part of this [3H]triphenyltin is eluted with a protein of Mr 5000-6000 on Sephadex LH20 chromatography. 2. Mössbauer spectra of the proteolipid fraction treated with 119Sn-enriched triethyltin chloride show a doublet which corresponds closely with that assigned previously [Farrow & Dawson (1978) Eur. J. Biochem. 86. 85-95] to the absorption of triethyltin bound to the high-affinity binding site of the mitochondrial ATPase. PMID:7082305

  18. High-sucrose diet increases ROS generation, FFA accumulation, UCP2 level, and proton leak in liver mitochondria.

    PubMed

    Ruiz-Ramírez, Angélica; Chávez-Salgado, Monserrath; Peñeda-Flores, José Antonio; Zapata, Estrella; Masso, Felipe; El-Hafidi, Mohammed

    2011-12-01

    Obesity, a risk factor for insulin resistance, contributes to the development of type 2 diabetes and cardiovascular diseases. The relationship between increased levels of free fatty acids in the liver mitochondria, mitochondrial function, and ROS generation in rat model of obesity induced by a high-sucrose diet was not sufficiently established. We determined how the bioenergetic functions and ROS generation of the mitochondria respond to a hyperlipidemic environment. Mitochondria from sucrose-fed rats generated H(2)O(2) at a higher rate than the control mitochondria. Adding fatty acid-free bovine serum albumin to mitochondria from sucrose-fed rats significantly reduced the rate of H(2)O(2) generation. In contrast, adding exogenous oleic or linoleic acid exacerbated the rate of H(2)O(2) generation in both sucrose-fed and control mitochondria, and the mitochondria from sucrose-fed rats were more sensitive than the control mitochondria. The increased rate of H(2)O(2) generation in sucrose-fed mitochondria corresponded to decreased levels of reduced GSH and vitamin E and increased levels of Cu/Zn-SOD in the intermembrane space. There was no difference between the levels of lipid peroxidation and protein carbonylation in the two types of mitochondria. In addition to the normal activity of Mn-SOD, GPX and catalase detected an increased activity of complex II, and upregulation of UCP2 was observed in mitochondria from sucrose-fed rats, all of which may accelerate respiration rates and reduce generation of ROS. In turn, these effects may protect the mitochondria of sucrose-fed rats from oxidative stress and preserve their function and integrity. However, in whole liver these adaptive mechanisms of the mitochondria were inefficient at counteracting redox imbalances and inhibiting oxidative stress outside of the mitochondria. PMID:21917631

  19. Huperzine A protects isolated rat brain mitochondria against beta-amyloid peptide.

    PubMed

    Gao, Xin; Zheng, Chun Yan; Yang, Ling; Tang, Xi Can; Zhang, Hai Yan

    2009-06-01

    Our previous work in cells and animals showed that mitochondria are involved in the neuroprotective effect of huperzine A (HupA). In this study, the effects of HupA on isolated rat brain mitochondria were investigated. In addition to inhibiting the Abeta(25-35) (40 microM)-induced decrease in mitochondrial respiration, adenosine 5'-triphosphate (ATP) synthesis, enzyme activity, and transmembrane potential, HupA (0.01 or 0.1 microM) effectively prevented Abeta-induced mitochondrial swelling, reactive oxygen species increase, and cytochrome c release. More interestingly, administration of HupA to isolated mitochondria promoted the rate of ATP production and blocked mitochondrial swelling caused by normal osmosis. These results indicate that HupA protects mitochondria against Abeta at least in part by preserving membrane integrity and improving energy metabolism. These direct effects on mitochondria further extend the noncholinergic functions of HupA. PMID:19272446

  20. The localization of some coenzyme A-dependant enzymes in rat liver mitochondria

    PubMed Central

    Haddock, B. A.; Yates, D. W.; Garland, P. B.

    1970-01-01

    1. CoA, acetyl-CoA, l-carnitine and acetyl-l-carnitine when added to rat liver mitochondria equilibrate with approximately two-thirds of the total intramitochondrial water. The mitochondrial space calculated to be freely permeable to these solutes was identical with that obtained for sucrose. 2. Acetyl-CoA is rapidly deacylated by rat liver mitochondria at 0°C, and special precautions are required to measure its mitochondrial permeation. 3. Rat liver mitochondria were separated into fractions that correspond to the inner membrane, the outer membrane, and the soluble proteins of the matrix and intermembrane compartment. Soluble enzymes considered to be located in the matrix were citrate synthase (EC 4.1.3.7), palmitoyl-CoA dehydrogenase (EC 1.3.2.2), electron-transferring flavoprotein, medium-chain-length ATP-specific fatty acyl-CoA synthetase (EC 6.2.1.2), l-3-hydroxybutyryl-CoA dehydrogenase (EC 1.1.1.35) and 3-keto-acyl-CoA thiolase (EC 2.3.1.16). Carnitine palmitoyltransferase (EC 2.3.1.–) is largely associated with the inner-membrane fraction. A long-chain-length ATP-specific fatty acyl-CoA synthetase (EC 6.2.1.3) is associated with the outer-membrane fraction. PMID:5500317

  1. The Cooperative Effect of Local Angiotensin-II in Liver with Adriamycin Hepatotoxicity on Mitochondria

    PubMed Central

    Taskin, Eylem; Guven, Celal; Sahin, Leyla; Dursun, Nurcan

    2016-01-01

    Background Adriamycin (ADR) is a drug used clinically for anticancer treatment; however, it causes adverse effects in the liver. The mechanism by which these adverse effects occur remains unclear, impeding efforts to enhance the therapeutic effects of ADR. Its hepatotoxicity might be related to increasing reactive oxygen species (ROS) and mitochondrial dysfunction. The interaction between ADR and the local renin-angiotensin system (RAS) in the liver is unclear. ADR might activate the RAS. Angiotensin-II (Ang-II) leads to ROS production and mitochondrial dysfunction. In the present study we investigated whether ADR’s hepatotoxicity interacts with local RAS in causing oxidative stress resulting from mitochondrial dysfunction in the rat liver. Material/Methods Rats were divided into 5 groups: control, ADR, co-treated ADR with captopril, co-treated ADR with Aliskiren, and co-treated ADR with both captopril and Aliskiren. Mitochondria and cytosol were separated from the liver, then biochemical measurements were made from them. Mitochondrial membrane potential (MMP) and ATP levels were evaluated. Results ADR remarkably decreased MMP and ATP in liver mitochondria (p<0.05). Co-administration with ADR and Aliskiren and captopril improved the dissipation of MMP (p<0.05). The decreased ATP level was restored by treatment with inhibitors of ACE and renin. Conclusions Angiotensin-II may contribute to hepatotoxicity of in the ADR via mitochondrial oxidative production, resulting in the attenuation of MMP and ATP production. PMID:27019222

  2. Mitochondria in traumatic brain injury and mitochondrial-targeted multipotential therapeutic strategies

    PubMed Central

    Cheng, Gang; Kong, Rong-hua; Zhang, Lei-ming; Zhang, Jian-ning

    2012-01-01

    Traumatic brain injury (TBI) is a major health and socioeconomic problem throughout the world. It is a complicated pathological process that consists of primary insults and a secondary insult characterized by a set of biochemical cascades. The imbalance between a higher energy demand for repair of cell damage and decreased energy production led by mitochondrial dysfunction aggravates cell damage. At the cellular level, the main cause of the secondary deleterious cascades is cell damage that is centred in the mitochondria. Excitotoxicity, Ca2+ overload, reactive oxygen species (ROS), Bcl-2 family, caspases and apoptosis inducing factor (AIF) are the main participants in mitochondria-centred cell damage following TBI. Some preclinical and clinical results of mitochondria-targeted therapy show promise. Mitochondria- targeted multipotential therapeutic strategies offer new hope for the successful treatment of TBI and other acute brain injuries. PMID:23003569

  3. Lipidomic analysis and electron transport chain activities in C57BL/6J mouse brain mitochondria

    PubMed Central

    Kiebish, Michael A.; Han, Xianlin; Cheng, Hua; Lunceford, Adam; Clarke, Catherine F.; Moon, Hwi; Chuang, Jeffrey H.; Seyfried, Thomas N.

    2011-01-01

    The objective of this study was to characterize the lipidome and electron transport chain activities in purified non-synaptic (NS) and synaptic (Syn) mitochondria from C57BL/6J mouse cerebral cortex. Contamination from subcellular membranes, especially myelin, has hindered past attempts to accurately characterize the lipid composition of brain mitochondria. An improved Ficoll and sucrose discontinuous gradient method was employed that yielded highly enriched mitochondrial populations free of myelin contamination. The activities of Complexes I, II, III, and II/III were lower in Syn than in NS mitochondria, while Complexes I/III and IV activities were similar in both populations. Shotgun lipidomics showed that levels of cardiolipin (Ptd2Gro) were lower, whereas levels of ceramide and phosphatidylserine were higher in Syn than in NS mitochondria. Coenzyme Q9 and Q10 was also lower in Syn than in NS mitochondria. Gangliosides, phosphatidic acid, sulfatides, and cerebrosides were undetectable in brain mitochondria. The distribution of Ptd2Gro molecular species was similar in both populations and formed a unique pattern, consisting of seven major molecular species groups, when arranged according to mass to charge ratios. Remodeling involving choline and ethanolamine phosphoglycerides could explain Ptd2Gro heterogeneity. NS and Syn mitochondrial lipidomic heterogeneity could influence energy metabolism, which may contribute to metabolic compartmentation of the brain. PMID:18373617

  4. Studies on the control of 4-aminobutyrate metabolism in 'synaptosomal' and free rat brain mitochondria.

    PubMed Central

    Walsh, J M; Clark, J B

    1976-01-01

    1. The specific activities of 4-aminobutyrate aminotransferase (EC 2.6.1.19) and succinate semialdehyde dehydrogenase (EC 1.2.1.16) were significantly higher in brain mitochondria of non-synaptic origin (fraction M) than those derived from the lysis of synaptosomes (fraction SM2). 2. The metabolisms of 4-aminobutyrate in both 'free' (non-synaptic, fraction M) and 'synaptic' (fraction SM2) rat brain mitochondria was studied under various conditions. 3. It is proposed that 4-aminobutyrate enters both types of brain mitochondria by a non-carrier-mediated process. 4. The rate of 4-aminobutyrate metabolism was in all cases higher in the 'free' (fraction M) brain mitochondria than in the synaptic (fraction SM2) mitochondria, paralleling the differences in the specific activities of the 4-aminobutyrate-shunt enzymes. 5. The intramitochondrial concentration of 2-oxoglutarate appears to be an important controlling parameter in the rate of 4-aminobutyrate metabolism, since, although 2-oxoglutarate is required, high concentrations (2.5 mM) of extramitochondrial 2-oxoglutarate inhibit the formation of aspartate via the glutamate-oxaloacetate transaminase. 6. The redox state of the intramitochondrial NAD pool is also important in the control of 4-aminobutyrate metabolism; NADH exhibits competitive inhibition of 4-aminobutyrate metabolism by both mitochondrial populations with an apparent Ki of 102 muM. 7. Increased potassium concentrations stimulate 4-aminobutyrate metabolsim in the synaptic mitochondria but not in 'free' brain mitochondria. This is discussed with respect to the putative transmitter role of 4-aminobutyrate. PMID:188415

  5. Biochemical and ultrastructural properties of osmotically lysed rat-liver mitochondria.

    PubMed

    Caplan, A I; Greenawalt, J W

    1966-12-01

    Isolated rat-liver mitochondria were osmotically lysed by suspension and washing 3 times in cold, distilled water. Pellets obtained by centrifugation at 105,000 g for 30 min were resuspended, fixed with glutaraldehyde and OsO(4), and embedded in Epon 812. Thin sections show the presence of two distinct membranous populations, each of which is relatively homogeneous in size and appearance. Swollen mitochondria ( approximately 1.5 micro in diameter), which have been stripped of their outer membranes, are largely devoid of matrix and normal matrix granules and are referred to as "ghosts." The smaller (0.2 to 0.4 micro in diameter), empty appearing, vesicular elements, derived primarily from the outer mitochondrial membrane, can be differentiated from the ghosts on the basis of their smaller size and complete absence of internal structures, especially cristae. Each membranous element is enclosed by a single, continuous membrane; the "double membrane" organization typical of intact mitochondria is not observed. These findings indicate that the outer membrane of rat-liver mitochondria is spatially dissociated from the inner mitochondrial membrane by osmotic lysis of the mitochondria in distilled water. Three parameters of structural and functional significance in freshly isolated rat-liver mitochondria have been correlated with the structural alterations observed: (a) chemical composition (total protein, lipid phosphate and total phosphate), (b) specific and total activities of marker enzymes for mitochondrial matrix and membranes (malate dehydrogenase (MDH), D-beta-hydroxybutyrate dehydrogenase (BDH) and cytochromes), and (c) integrated multienzyme functions (respiration, phosphorylation, and contraction). The data presented indicate that all mitochondrial membranes are completely conserved in the crude ghost preparation and that, in addition, about (1/3) of the matrix proteins (estimated by assays for MDH activity and protein) are retained. The study of integrated

  6. Regulation of drug-induced liver injury by signal transduction pathways: critical role of mitochondria.

    PubMed

    Han, Derick; Dara, Lily; Win, Sanda; Than, Tin Aung; Yuan, Liyun; Abbasi, Sadeea Q; Liu, Zhang-Xu; Kaplowitz, Neil

    2013-04-01

    Drugs that cause liver injury often 'stress' mitochondria and activate signal transduction pathways important in determining cell survival or death. In most cases, hepatocytes adapt to the drug-induced stress by activating adaptive signaling pathways, such as mitochondrial adaptive responses and nuclear factor erythroid 2-related factor 2 (Nrf-2), a transcription factor that upregulates antioxidant defenses. Owing to adaptation, drugs alone rarely cause liver injury, with acetaminophen (APAP) being the notable exception. Drug-induced liver injury (DILI) usually involves other extrinsic factors, such as the adaptive immune system, that cause 'stressed' hepatocytes to become injured, leading to idiosyncratic DILI, the rare and unpredictable adverse drug reaction in the liver. Hepatocyte injury, due to drug and extrinsic insult, causes a second wave of signaling changes associated with adaptation, cell death, and repair. If the stress and injury reach a critical threshold, then death signaling pathways such as c-Jun N-terminal kinase (JNK) become dominant and hepatocytes enter a failsafe mode to undergo self-destruction. DILI can be seen as an active process involving recruitment of death signaling pathways that mediate cell death rather than a passive process due to overwhelming biochemical injury. In this review, we highlight the role of signal transduction pathways, which frequently involve mitochondria, in the development of DILI. PMID:23453390

  7. The pathway of inorganic-phosphate efflux from isolated liver mitochondria during adenosine triphosphate hydrolysis.

    PubMed

    Tyler, D D

    1980-12-15

    1. The distribution of P(i) between mitochondria and suspending medium during uncoupler-stimulated hydrolysis of ATP by rat liver mitochondria [Tyler (1969) Biochem. J.111, 665-678] has been reinvestigated, by using either mersalyl or N-ethylmaleimide as inhibitors of P(i) transport and either buffered sucrose/EDTA or LiCl/EGTA solutions as suspending medium. More than 75% of the total P(i) liberated was retained in mitochondria treated with either inhibitor at all ATP concentrations tested (0.2-2.5mm). With low ATP concentrations and mersalyl-treated mitochondria incubated in sucrose/EDTA, virtually all the P(i) liberated was retained in the mitochondria. 2. Larger amounts of P(i) appeared in the suspending medium during ATPase activity, despite the presence of N-ethylmaleimide, when LiCl/EGTA was used as suspending medium compared with sucrose/EDTA. Two sources of this P(i) were identified: (a) a slow efflux of P(i) from mitochondria to suspending medium despite the presence of N-ethylmaleimide; (b) a slow ATPase activity insensitive to carboxyatractyloside, which was stimulated by added Mg(2+), partially inhibited by oligomycin or efrapeptin and strongly inhibited by EDTA. 3. It is concluded that liver mitochondria preparations contain two distinct forms of ATPase activity. The major activity is associated with coupled mitochondria of controlled permeability to adenine nucleotides and P(i) and is stimulated strongly by uncoupling agents. The minor activity is associated with mitochondria freely permeable to adenine nucleotides and P(i), is unaffected by uncoupling agents and is activated by endogenous or added Mg(2+). 4. When mitochondria treated with mersalyl were incubated in buffered sucrose solution, almost all the P(i) liberated was recovered in the suspending medium, unless inhibitors of P(i)-induced large-amplitude swelling such as EDTA, EGTA, antimycin, rotenone, nupercaine or Mg(2+) were added. Thus the loss of the specific permeability properties of

  8. Abamectin affects the bioenergetics of liver mitochondria: A potential mechanism of hepatotoxicity.

    PubMed

    Castanha Zanoli, Juliana C; Maioli, Marcos A; Medeiros, Hyllana C D; Mingatto, Fábio E

    2012-02-01

    Abamectin (ABA) is a macrocyclic lactone of the avermectin family used worldwide as an antiparasitic agent in farm animals and pets and as the active ingredient of insecticides and nematicides. In this study, the effects of abamectin on the bioenergetics of mitochondria isolated from rat liver were evaluated. Mitochondria are responsible for converting the energy released by electron transport and stored as the binding energy molecule ATP. Xenobiotics that interfere with its synthesis or utilization can be acutely or chronically toxic. Abamectin (5-25μM) caused concentration-dependent inhibition of the respiratory chain without affecting the membrane potential or the activity of enzymes NADH dehydrogenase or succinate dehydrogenase. This behavior is similar to oligomycin and carboxyatractyloside and suggests direct action on F(o)F(1)-ATPase and/or the adenine nucleotide translocator (ANT). ABA more pronouncedly inhibited ATPase phosphohydrolase activity in intact, uncoupled mitochondria than in freeze-thawed disrupted mitochondria. ADP-stimulated depolarization of the mitochondrial membrane potential was also inhibited by ABA. Our results indicate that ABA interacts more specifically with the ANT, resulting in functional inhibition of the translocator with consequent impairment of mitochondrial bioenergetics. This effect could be involved in the ABA toxicity to hepatocytes. PMID:22024101

  9. Selective permeability of rat liver mitochondria to purified malate dehydrogenase isoenzymes in vitro.

    PubMed Central

    Passarella, S; Marra, E; Doonan, S; Quagliariello, E

    1980-01-01

    1. The mitochondrial malate dehydrogenase from rat liver has been purified to a state of homogeneity as judged by starch-gel electrophoresis and the cytoplasmic isoenzyme has been obtained in a partically purified state. 2. Inhibition of the isoenzymes by sulphite has been studied. 3. In mitochondria loaded with sulphite, the catalytic activity of the (partially inhibited) internal malate dehydrogenase has been measured by addition of oxaloacetate to the suspension medium and observation of the consequent decrease in fluorescence of NADH. 4. Addition of mitochondrial malate dehydrogenase to suspensions of mitochondria loaded with sulphite resulted in an increase in the level of intramitochondrial enzymic activity as measured by the above technique. Addition of the cytoplasmic isoenzyme did not result in such an increase. 5. These results show that mitochondria in suspension are permeable to the mitochondrial malate dehydrogenase but not to the cytoplasmic isoenzyme. 6. This conclusion has been confirmed by direct measurement of a decrease of enzyme activity in solution and an increase inside the mitochondria after incubation of organelles in solutions containing mitochondrial malate dehydrogenase. No such effect was observed with the cytoplasmic isoenzyme. 7. Some features of the permeation process have been studied. PMID:7236231

  10. Release of matrix proteins from mitochondria to cytosol during the prereplicative phase of liver regeneration.

    PubMed

    Greco, M; Moro, L; Pellecchia, G; Di Pede, S; Guerrieri, F

    1998-05-01

    70% partial hepatectomy (PH) in the rat causes a release, into the cytosolic fraction, of mitochondrial matrix proteins, namely the mitochondrial isoform of aspartate aminotransferase (mAAT) and malate dehydrogenase (MDH), during the first 24 h after PH, when no growth of the residual liver is observed. After this time interval, the weight of the liver starts to increase and the normal weight is reached at 96 h after PH. This proliferative phase is characterized by a progressive recovery of the normal levels of intramitochondrial activities of mAAT and MDH. Mitochondria isolated at 24 h after PH show a membrane permeabilization to sucrose accompanied by a release of matrix enzymes; both are blocked by cyclosporin A. These results suggest an alteration of mitochondrial membrane integrity, during the prereplicative phase of liver regeneration, with the occurrence of an increased permeability that allows the passage into the cytosol of matrix enzymes. PMID:9607307

  11. Superstoichiometric Ca2+ uptake supported by hydrolysis of endogenous ATP in rat liver mitochondria.

    PubMed

    Brand, M D; Lehninger, A L

    1975-10-10

    The nature of the energy store causing rapid superstoichiometric leads to H+/2e minus ejection and leads to Ca2+/2e minus uptake ratios in rat liver mitochondria pulsed with Ca2+ has been investigated. The extent and the rate of the initial fast superstoichiometric phase of H plus ejection were greatly reduced by oligomycin and other ATPase inhibitors; the subsequent shoichiometric phase was unaffected. No such inhibition was seen with atractyloside. Similarly, the initial fast phase of Ca2+ uptake was reduced in extent by oligomycin, whereas the slower stoichiometric phase was unaffected. Moreover, the ATP content of mitochondria previously incubated with succinate decreased by about 80% within 5 s after pulsing with Ca2+. The energy store for superstoichiometric Ca2+ uptake and H plus injection is thus identified as endogenous ATP. PMID:1176454

  12. Freeze-dried grape powder attenuates mitochondria- and oxidative stress-mediated apoptosis in liver cells.

    PubMed

    Xu, Yumin; Khaoustov, Vladimir I; Wang, Hui; Yu, Jing; Tabassam, Fazal; Yoffe, Boris

    2009-10-14

    The beneficial effects of grape consumption have been attributed to the antioxidant activity of its polyphenols. This study was conducted to investigate the cytoprotective effects of a freeze-dried grape powder (FDGP) on liver cells. FDGP treatment of primary hepatocytes and hepatoma cells revealed increased metabolic activity of cells and phosphorylation of Akt and IkappaBalpha, as well as up-regulation of proliferating cell nuclear antigen (PCNA) level. To study the molecular mechanisms of FDGP effects, cells were treated with TNF-related apoptosis-inducing ligand (TRAIL); taurodeoxycholic acid (TDCA); thapsigargin (TG), to induce cell apoptosis through death receptor-, mitochondria-, or ER-mediated pathway; and H(2)O(2), to induce oxidative stress, respectively. TDCA-induced activation of caspase-3, caspase-7, caspase-9, and Bax was dramatically decreased with cotreatment of FDGP. Furthermore, FDGP reduced levels of annexin V positive cells by 4-fold. Also, FDGP pretreatment restored cellular glutathione content by 71% in cells treated with H(2)O(2). However, FDGP did not inhibit ER-mediated apoptosis. In conclusion, FDGP increased the viability and metabolic activity of liver cells and attenuated oxidative stress- and mitochondria-mediated apoptosis. These data may contribute to the understanding of the mechanisms involved in protective effects of grape in a variety of liver conditions associated with cellular stress. PMID:19754144

  13. Alterations of mitochondria in liver but not in heart homogenates after treatment of rats with benznidazole.

    PubMed

    Rendon, D A

    2014-10-01

    The mitochondrial oxidative phosphorylation system was studied in liver and heart homogenates after treatment of rats with benznidazole. The drug was given by oral gavage to adult female Wistar rats for 9 consecutive days (100 mg benznidazole/kg body weight as a daily dose). The mitochondrial state 4 and state 3 respiration rates, respiratory control, efficiency of oxidative phosphorylation (ADP/O), and ATPsynthase activity were assayed. The results showed that according to all these parameters, the mitochondria in cardiac homogenates were not affected in the rats treated with benznidazole. By contrast, mitochondria in the liver homogenates of drug-treated rats were altered, showing decreased respiratory control and a lower coefficient of ADP/O as a result of an increase in the state 4 respiration rate. These data indicate the possibility of production of an uncoupling factor leading to increased proton leakage through the inner mitochondrial membrane as a result of a 9-day treatment of rats with benzonidazole. The obtained experimental data might at least partly explain the nature of benznidazole toxicity in the liver treated with benznidazole. PMID:24505051

  14. Lack of manifestations of diazoxide/5-hydroxydecanoate-sensitive KATP channel in rat brain nonsynaptosomal mitochondria

    PubMed Central

    Brustovetsky, Tatiana; Shalbuyeva, Natalia; Brustovetsky, Nickolay

    2005-01-01

    Pharmacological modulation of the mitochondrial ATP-sensitive K+ channel (mitoKATP) sensitive to diazoxide and 5-hydroxydecanoate (5-HD) represents an attractive strategy to protect cells against ischaemia/reperfusion- and stroke-related injury. To re-evaluate a functional role for the mitoKATP in brain, we used Percoll-gradient-purified brain nonsynaptosomal mitochondria in a light absorbance assay, in radioisotope measurements of matrix volume, and in measurements of respiration, membrane potential (ΔΨ) and depolarization-induced K+ efflux. The changes in mitochondrial morphology were evaluated by transmission electron microscopy (TEM). Polyclonal antibodies raised against certain fragments of known sulphonylurea receptor subunits, SUR1 and SUR2, and against different epitopes of K+ inward rectifier subunits Kir 6.1 and Kir 6.2 of the ATP-sensitive K+ channel of the plasma membrane (cellKATP), were employed to detect similar subunits in brain mitochondria. A variety of plausible blockers (ATP, 5-hydroxydecanoate, glibenclamide, tetraphenylphosphonium cation) and openers (diazoxide, pinacidil, chromakalim, minoxidil, testosterone) of the putative mitoKATP were applied to show the role of the channel in regulating matrix volume, respiration, and ΔΨ and K+ fluxes across the inner mitochondrial membrane. None of the pharmacological agents applied to brain mitochondria in the various assays pinpointed processes that could be unequivocally associated with mitoKATP activity. In addition, immunoblotting analysis did not provide explicit evidence for the presence of the mitoKATP, similar to the cellKATP, in brain mitochondria. On the other hand, the depolarization-evoked release of K+ suppressed by ATP could be re-activated by carboxyatractyloside, an inhibitor of the adenine nucleotide translocase (ANT). Moreover, bongkrekic acid, another inhibitor of the ANT, inhibited K+ efflux similarly to ATP. These observations implicate the ANT in ATP-sensitive K+ transport in

  15. Analysis of Brain Mitochondria Using Serial Block-Face Scanning Electron Microscopy.

    PubMed

    Mukherjee, Konark; Clark, Helen R; Chavan, Vrushali; Benson, Emily K; Kidd, Grahame J; Srivastava, Sarika

    2016-01-01

    Human brain is a high energy consuming organ that mainly relies on glucose as a fuel source. Glucose is catabolized by brain mitochondria via glycolysis, tri-carboxylic acid (TCA) cycle and oxidative phosphorylation (OXPHOS) pathways to produce cellular energy in the form of adenosine triphosphate (ATP). Impairment of mitochondrial ATP production causes mitochondrial disorders, which present clinically with prominent neurological and myopathic symptoms. Mitochondrial defects are also present in neurodevelopmental disorders (e.g. autism spectrum disorder) and neurodegenerative disorders (e.g. amyotrophic lateral sclerosis, Alzheimer's and Parkinson's diseases). Thus, there is an increased interest in the field for performing 3D analysis of mitochondrial morphology, structure and distribution under both healthy and disease states. The brain mitochondrial morphology is extremely diverse, with some mitochondria especially those in the synaptic region being in the range of <200 nm diameter, which is below the resolution limit of traditional light microscopy. Expressing a mitochondrially-targeted green fluorescent protein (GFP) in the brain significantly enhances the organellar detection by confocal microscopy. However, it does not overcome the constraints on the sensitivity of detection of relatively small sized mitochondria without oversaturating the images of large sized mitochondria. While serial transmission electron microscopy has been successfully used to characterize mitochondria at the neuronal synapse, this technique is extremely time-consuming especially when comparing multiple samples. The serial block-face scanning electron microscopy (SBFSEM) technique involves an automated process of sectioning, imaging blocks of tissue and data acquisition. Here, we provide a protocol to perform SBFSEM of a defined region from rodent brain to rapidly reconstruct and visualize mitochondrial morphology. This technique could also be used to provide accurate information on

  16. 'Pore' formation is not required for the hydroperoxide-induced Ca2+ release from rat liver mitochondria.

    PubMed Central

    Schlegel, J; Schweizer, M; Richter, C

    1992-01-01

    It has recently been suggested by several investigators that the hydroperoxide- and phosphate-induced Ca2+ release from mitochondria occurs through a non-specific 'pore' formed in the mitochondrial inner membrane. The aim of the present study was to investigate whether 'pore' formation actually is required for Ca2+ release. We find that the t-butyl hydroperoxide (tbh)-induced release is not accompanied by stimulation of sucrose entry into, K+ release from, and swelling of mitochondria provided re-uptake of the released Ca2+ ('Ca2+ cycling') is prevented. We conclude that (i) the tbh-induced Ca2+ release from rat liver mitochondria does not require 'pore' formation in the mitochondrial inner membrane, (ii) this release occurs via a specific pathway from intact mitochondria, and (iii) a non-specific permeability transition ('pore' formation) is likely to be secondary to Ca2+ cycling by mitochondria. PMID:1379041

  17. Protective effect of Cichorium glandulosum seeds from ultraviolet B-induced damage in rat liver mitochondria.

    PubMed

    Huang, Bo; Chen, Yuxin; Ma, Bingxin; Zhou, Gao; Tong, Jing; He, Jingsheng; Wang, Youwei

    2014-05-01

    Cichorium glandulosum Boiss. et Huet, a common herb for treating hepatitis, is indigenous to Europe, Western Asia, and the Xinjiang Uygur Autonomous Region of China. This study aims at evaluating the protective activity of different extracts from C. glandulosum seeds against experimental oxidation- and ultraviolet B (UVB)-induced damage in rat liver mitochondria. The antioxidant property of different extracts from C. glandulosum seeds was investigated by employing various established in vitro systems, such as α,α-diphenyl-β-picrylhydrazyl, 2,2'-azinobis(3-ethylbenzthiazoline-6-sulphonic acid), and reducing power assay. The protective effects of different C. glandulosum seed extracts against UVB-induced phototoxicity in a mitochondria model were also evaluated by measuring thiobarbituric acid reactive substances, glutathione, lipid hydroperoxide, conjugated diene, and 4-hydroxynonenal. The main compounds in C. glandulosum seeds were identified by HPLC-PDA-ESI-MS/MS. The results showed that C. glandulosum seed extracts have strong antioxidant activity, in which the ethyl acetate extract (EE) and n-butanol extract (BE) showed better activity than other extracts. In a UVB-induced mitochondria model, both EE and BE have better antioxidant activity and protective effects against phototoxicity than the petroleum ether extract, chloroform extract, and water extract. The differences in antioxidant activity and photoprotective capacity among these five extracts are associated with their phenolic compound content. Therefore, research on this function of C. glandulosum seeds may broaden their applications in the food and medical industry. PMID:24595542

  18. Role of berberine against arsenic induced oxidative damage in isolated rat liver mitochondria.

    PubMed

    Khodayar, Mohammad Javad; Javadipour, Mansoureh; Keshtzar, Elham; Rezaei, Mohsen

    2016-03-01

    The aim of the present study was to assess the protective role of berberine against toxicity induced by arsenic in mitochondria from liver of rat. The level of reactive oxygen species and mitochondrial membrane potential changes were evaluated spectrofluorometrically. 20, 40 and 100 μM arsenic concentration increased ROS level approximately by 13.5, 21.3 and 29 %. However, when pretreated mitochondria with berberine (10, 25, 50 μM) were exposed to arsenic (20, 40 and 100 μM), ROS production diminished. Also, for all arsenic concentration mitochondrial membrane damage was detected to be 2.5, 4.8 and 7.26 % respectively. Pretreatment with berberine even at highest concentration (50μM) was not able to retain membrane potential as compared to control. These results showed that mitochondria were significantly affected when exposed to arsenic, forcedly directed toward excess ROS production and mitochondrial membrane disruption. Pretreatment with berberine, reduced ROS generation but did not restore mitochondrial membrane integrity. PMID:27097449

  19. [The effect of altan on the functional activity of the liver mitochondria and microsomes from rats with toxic hepatitis].

    PubMed

    Gordienko, A D; Iakovleva, L V

    1999-01-01

    In in vitro experiments althan had no effect on the respiration of intact mitochondria in state 4 according to Chance and produced a high antioxidant effect in fermentative and ascorbate-dependent lipid peroxidation in intact microsomes isolated from the rat liver. In ethanol-induced toxic hepatitis althan restored the functional activity of mitochondria to the level of that in intact animals and increased microsome hydroxylase activity in CCl4-hepatitis. PMID:10513340

  20. The Role of Mitochondria in Brain Aging and the Effects of Melatonin

    PubMed Central

    Escames, Germaine; López, Ana; García, José Antonio; García, Laura; Acuña-Castroviejo, Darío; García, José Joaquín; López, Luis Carlos

    2010-01-01

    Melatonin is an endogenous indoleamine present in different tissues, cellular compartments and organelles including mitochondria. When melatonin is administered orally, it is readily available to the brain where it counteracts different processes that occur during aging and age-related neurodegenerative disorders. These aging processes include oxidative stress and oxidative damage, chronic and acute inflammation, mitochondrial dysfunction and loss of neural regeneration. This review summarizes age related changes in the brain and the importance of oxidative/nitrosative stress and mitochondrial dysfunction in brain aging. The data and mechanisms of action of melatonin in relation to aging of the brain are reviewed as well. PMID:21358969

  1. Factors affecting the translocation of oxaloacetate and L-malate into rat liver mitochondria.

    PubMed

    Haslam, J M; Griffiths, D E

    1968-10-01

    1. The rates of translocation of oxaloacetate and l-malate into rat liver mitochondria were measured by a direct spectrophotometric assay. 2. Penetration obeyed Michaelis-Menten kinetics, and apparent K(m) values were 40mum for oxaloacetate and 0.13mm for l-malate. 3. Arrhenius plots of the temperature-dependence of rates of penetration gave activation energies of +10kcal./mole for oxaloacetate and +8kcal./mole for l-malate. 4. The translocation of both oxaloacetate and l-malate was competitively inhibited by d-malate, succinate, malonate, meso-tartrate, maleate and citraconate. The K(i) values of these inhibitors were similar for the penetration of both oxaloacetate and l-malate. 5. Rates of penetration were stimulated by NNN'N'-tetramethyl-p-phenylenediamine dihydrochloride plus ascorbate under aerobic conditions or by ATP under anaerobic conditions. 6. The energy-dependent stimulation of translocation was abolished by uncouplers of oxidative phosphorylation. Oligomycin A, aurovertin, octyl-guanidine and atractyloside prevented the stimulation by ATP, but did not inhibit the stimulation by NNN'N'-tetramethyl-p-phenylenediamine dihydrochloride plus ascorbate. 7. Mitochondria prepared in the presence of ethylene-dioxybis(ethyleneamino)tetra-acetic acid did not exhibit the energy-dependent translocation, but this could be restored by the addition of 50mum-calcium chloride. 8. Valinomycin or gramicidin plus potassium chloride enhanced the energy-dependent translocation of oxaloacetate and l-malate. 9. Addition of oxaloacetate stimulated the adenosine triphosphatase activity of the mitochondria, and the ratio of ;extra' oxaloacetate translocation to ;extra' adenosine triphosphatase activity was 1.6:1. 10. Possible mechanisms for the energy-dependent entry of oxaloacetate and l-malate into mitochondria are discussed in relation to the above results. PMID:4235143

  2. Investigation of proton conductance in liver mitochondria of broilers with pulmonary hypertension syndrome.

    PubMed

    Cawthon, D; Iqbal, M; Brand, J; McNew, R; Bottje, W G

    2004-02-01

    We previously reported an impaired ability to regulate hepatic mitochondrial state 4 respiration rate in response to sequential additions of adenosine diphosphate in pulmonary hypertension syndrome (PHS). As proton conductance is a major contributor to State 4 respiration, the major goal of this study was to investigate the nature of proton conductance in hepatic mitochondria isolated from broilers with and without PHS. Broilers were placed on floor litter in environmental chambers and exposed to cold temperatures (15 degrees C) from 3 to 7 wk of age to induce PHS. Liver mitochondria were isolated from birds that exhibited PHS (cyanosis, right ventricular weight ratio > 0.30) or from birds that appeared healthy (no cyanosis, right ventricular weight ratio < 0.27). Isolated mitochondria were placed in a chamber equipped with the ability to measure oxygen content and mitochondrial membrane potential. The mitochondrial membrane potential was assessed by an ion sensitive electrode to measure the distribution of methyltriphenylphosphonium across the inner mitochondrial membrane. Proton conductance was assessed by simultaneously measuring State 4 oxygen consumption rate as respiration was progressively inhibited with increasing concentrations of malonate. The addition of cardiolipin, a lipid found in high concentrations in mitochondrial membranes that can alter proton conductance, had no affect on respiration or mitochondrial membrane potential in either group. The relationship of curves depicting State 4 respiration and mitochondrial membrane potential indicates that PHS mitochondria exhibit impaired substrate oxidation and reduced proton conductance relative to controls. These findings provide further characterization of the altered cellular oxygen utilization in broilers with PHS. PMID:14979578

  3. Regulation of free Ca2+ by liver mitochondria and endoplasmic reticulum.

    PubMed

    Becker, G L; Fiskum, G; Lehninger, A L

    1980-10-10

    Electrode measurements were made of the free Ca2+ concentration maintained by suspensions of isolated rat liver mitochondria and microsomes, as well as by hepatocytes whose plasma membranes had been made permeable by treatment with digitonin. When the KCl, ATP, Mg2+, and phosphate concentrations were made similar to that of cytosol, the steady state free Ca2+ concentration in the presence of respiring mitochondria alone was about 0.5 microM. The additional presence of rat liver microsomes resulted in a steady state level of close to 0.2 microM, which was maintaied for greater than 1 h at 25 degrees C. This concentration of Ca2+ was also maintained by suspensions of hepatocytes permeabilized by digitonin and thus may approximate the actual cytosolic free Ca2+ concentration in vivo. The "set point" for free Ca2+ homeostasis in these systems is determined by mitochondrial Ca2+ influx-efflux cycling, which is dependent on the level of intramitochondrial Ca2+ and can be adjusted by sequestration of Ca2+ in microsomes. PMID:7410406

  4. Inhibition of ATP synthesis by fenbufen and its conjugated metabolites in rat liver mitochondria.

    PubMed

    Syed, Muzeeb; Skonberg, Christian; Hansen, Steen Honoré

    2016-03-01

    Fenbufen is an arylpropionic acid derivative belonging to the group of non-steroidal anti-inflammatory drugs (NSAIDs). Even though fenbufen is considered a safe drug, some adverse reactions including hepatic events have been reported. To investigate whether mitochondrial damage could be involved in the drug induced liver injury (DILI) by fenbufen, the inhibitory effect of fenbufen and its conjugated metabolites on oxidative phosphorylation (ATP synthesis) in rat liver mitochondria was investigated. Fenbufen glucuronide (F-GlcA), fenbufen-N-acetyl cysteine-thioester (F-NAC) and fenbufen-S-glutathione thioester (F-SG) were found to be more potent inhibitors compared to parent fenbufen (F), whereas fenbufen-O-carnitine (F-carn), fenbufen-glycine (F-gly) and fenbufen-N-acetyl lysine amide (F-NAL) were less potent compared to fenbufen. Fenbufen-CoA thioester (F-CoA) was equally potent as fenbufen in inhibiting ATP synthesis. Fenbufen showed time and concentration dependent inhibition of ATP synthesis with Kinact of 4.4 min(-1) and KI of 0.88 μM and Kinact/KI ratio of 5.01 min(-1) μM(-1). Data show that fenbufen did not act through opening MPT pore, nor did incubation of mitochondria with reduced GSH and fenbufen show any protective effect on fenbufen mediated inhibition of oxidative phosphorylation. Inclusion of NADPH in mitochondrial preparations with fenbufen did not modulate the inhibitory effects, suggesting no role of CYP mediated oxidative metabolites on the ATP synthesis in isolated mitochondria. The results from the present experiments provide evidence that fenbufen and its metabolites could be involved in mitochondrial toxicity through inhibition of ATP synthesis. PMID:26612354

  5. 3'-Azido-3'-deoxythmidine uptake into isolated rat liver mitochondria and impairment of ADP/ATP translocator.

    PubMed

    Barile, M; Valenti, D; Passarella, S; Quagliariello, E

    1997-04-01

    To gain some insight into the mechanism by which 3'-azido-3'-deoxythymidine (AZT) impairs mitochondrial metabolism, [14C]AZT uptake by rat liver mitochondria (RLM) in vitro was investigated. AZT accumulated in mitochondria in a time-dependent manner and entered the mitochondrial matrix. The rate of AZT uptake into mitochondria showed a hyperbolic dependence on the drug concentration and was inhibited by mersalyl, a thiol reagent that cannot enter mitochondria, thus showing that a membrane protein is involved in AZT transport. Investigation into the capability of AZT to affect certain mitochondrial carriers demonstrated that AZT was able to impair the ADP/ATP translocator, but had no effect on Pi, dicarboxylate, tricarboxylate, or oxodicarboxylate carriers. AZT inhibited ADP/ATP antiport in either mitochondria or mitoplasts in a competitive manner with different sensitivity (Ki values were 18.3 +/- 2.9 and 70.2 +/- 5.8 microM, respectively). Consistent with this were isotopic measurements showing that AZT accumulates in the intermembrane space. AZT does not use ADP/ATP carrier to enter mitochondria, as shown by the failure of both carboxyatractyloside (CAT) to inhibit AZT transport into mitochondria and AZT to induce ATP efflux from ATP-loaded mitochondria. ADP/ATP translocator impairment by AZT as one of the biochemical processes responsible for the ATP deficiency syndrome is discussed. PMID:9174103

  6. Brain aging and mitochondria-targeted plastoquinone antioxidants of SkQ-type.

    PubMed

    Isaev, N K; Stelmashook, E V; Stelmashook, N N; Sharonova, I N; Skrebitsky, V G

    2013-03-01

    Normal brain aging leads to decrease in cognitive functions, shrink in brain volume, loss of nerve fibers and degenerating myelin, reduction in length and branching of dendrites, partial loss of synapses, and reduction in expression of genes that play central roles in synaptic plasticity, vesicular transport, and mitochondrial functioning. Impaired mitochondrial functions and mitochondrial reactive oxygen species can contribute to the damage of these genes in aging cerebral cortex. This review discusses the possibility of using mitochondria-targeted antioxidants to slow the processes of brain aging. PMID:23586724

  7. Disequilibrium in the malate dehydrogenase reaction in rat liver mitochondria in vivo

    PubMed Central

    Heath, D. F.; Phillips, J. C.

    1972-01-01

    1. When [2-14C]pyruvate is injected into rats the C3-position of liver glutamate becomes more heavily labelled than the C2-position, thus establishing that oxaloacetate and fumarate are not in equilibrium in rat liver mitochondria in vivo. The amount of disequilibrium was shown to be simply related to the value that the C3-label/C2-label ratio would have were no label recycled. This ratio, z, was calculated for post-absorptive rats in environmental temperatures of 20° and 30°C from determinations of the distribution of label within glutamate 1, 3 and 10min after intravenous injection of [2-14C]pyruvate. The values of z (best estimate and range) were 1.65 (1.60–1.69) in rats at 20°C and 2.43 (2.23–2.63) in rats at 30°C. These values of z imply the following rates of interconversion in mitochondria of fumarate and oxaloacetate (in terms of the oxaloacetate→citrate flux, R) in rats at 20°C: [Formula: see text] and in rats at 30°C: [Formula: see text] 2. The kinetic parameters of malate dehydrogenase and fumarate hydratase and the intramitochondrial concentrations of NAD+ and NADH under (as far as could be judged) conditions in vivo were collated. From them and the best estimates of R now available were calculated the rates of interconversion of fumarate, malate and oxaloacetate required to give the found values of z. These rates showed that the fumarate hydratase reaction was nearly in equilibrium, but that the malate dehydrogenase reaction was considerably out of equilibrium. The calculations also led to the following conclusions. 3. In livers of rats at 20° and 30°C mitochondrial malate concentrations were respectively about 5 and 1.5 times mean cellular concentrations. 4. Mitochondrial oxaloacetate concentrations were less than 0.2 of the mean cellular concentrations. They were also only 0.65 and 0.55 of the equilibrium concentrations for the malate dehydrogenase reaction in rats at 20° and 30°C respectively. 5. Malate dehydrogenase activity was low

  8. Acid–base titration across the membrane system of rat-liver mitochondria

    PubMed Central

    Mitchell, Peter; Moyle, Jennifer

    1967-01-01

    1. Pulsed acid–base titrations of suspensions of rat-liver mitochondria under anaerobic equilibrium conditions show fast and slow titration processes. 2. The fast process is the titration of the outer aqueous phase of the mitochondria, which is continuous with the suspension medium, and the slow process can be identified with the titration of the inner aqueous phase of the mitochondria, which is separated from the outer aqueous phase by the non-aqueous osmotic barrier or M phase of the cristae membrane system. 3. The buffering power of the outer and inner phases have been separately measured over a range of pH values. 4. The rate of titration of the inner aqueous phase under a known protonmotive force across the M phase has been characterized by an effective proton conductance coefficient, which, near pH7 and at 25°, is only 0·45μmho/cm.2 of the M-phase membrane. 5. The low effective proton conductance of the M phase will account quantitatively for the observed respiratory control in state 4, assuming that oxidoreduction and phosphorylation are coupled by a circulating proton current as required by the chemi-osmotic hypothesis. 6. The addition of 2,4-dinitrophenol (or carbonyl cyanide p-trifluoromethoxyphenylhydrazone) at normal uncoupling concentrations causes a large increase in the effective proton conductance of the M phase of the cristae membrane. 7. The increase of the effective proton conductance of the M phase by 2,4-dinitrophenol (or carbonyl cyanide p-trifluoromethoxyphenylhydrazone) will account quantitatively for the short-circuiting effect of the uncoupling agent on the proton current and for the observed rise of the rate of respiration to that characteristic of state 3 or higher. PMID:6048801

  9. Identification of phosphorylated form of 2', 3'-cyclic nucleotide 3'-phosphodiesterase (CNPase) as 46 kDa phosphoprotein in brain non-synaptic mitochondria overloaded by calcium.

    PubMed

    Azarashvili, Tamara; Krestinina, Olga; Galvita, Anastasia; Grachev, Dmitry; Baburina, Yulia; Stricker, Rolf; Reiser, Georg

    2014-04-01

    In our previous studies phosphorylation of several membrane-bound proteins in brain and liver mitochondria were found to be regulated by Ca(2+) as a second messenger. One of the proteins, the 46 kDa phosphoprotein was found to be highly phosphorylated when Ca(2+)-induced permeability transition pore (mPTP) was opened in rat brain mitochondria (RBM). In the present study the 46 kDa phosphoprotein was identified as 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNPase) after purification by 2D diagonal electrophoresis following mass spectrometric analysis and Western blot probed with anti-CNP antibody. CNPase was discovered in immunoprecipitates of mitochondria, phosphorylated under both conditions (control and with opened mPTP). Status phosphorylation of CNPase was found to be higher in the inmmunoprecipiates of calcium-overloaded RBM. The phospohoserine and phosphotyrosine residues were detected in phosphorylated 46 kDa band (CNPase) as well as in CNPase immunoprecipitates indicating possible participation of tyrosine and serine protein kinases in phosphorylation of CNPase in mitochondria. The levels of phospo-Ser and phospho-Tyr were increased in RBM with mPTP opened. It was found that CNPase substrate, 2',3'-cAMP (5 μM) and, a non-competitive CNPase inhibitor, atractyloside (5 μM), were able to increase the level of CNPase phosphorylation in calcium-overloaded mitochondria, while CsA (mPTP blocker) was able to strong suppress the phosphorylation of the enzyme. Collectively, our results provide evidence that Ca(2+)-stimulated and mPTP-associated CNPase phosphorylation might be an important stage of mPTP regulation in mitochondria, revealing a new function of CNPase outside of myelin structure. PMID:24532135

  10. Ca(2+) handling in isolated brain mitochondria and cultured neurons derived from the YAC128 mouse model of Huntington's disease.

    PubMed

    Pellman, Jessica J; Hamilton, James; Brustovetsky, Tatiana; Brustovetsky, Nickolay

    2015-08-01

    We investigated Ca(2+) handling in isolated brain synaptic and non-synaptic mitochondria and in cultured striatal neurons from the YAC128 mouse model of Huntington's disease. Both synaptic and non-synaptic mitochondria from 2- and 12-month-old YAC128 mice had larger Ca(2+) uptake capacity than mitochondria from YAC18 and wild-type FVB/NJ mice. Synaptic mitochondria from 12-month-old YAC128 mice had further augmented Ca(2+) capacity compared with mitochondria from 2-month-old YAC128 mice and age-matched YAC18 and FVB/NJ mice. This increase in Ca(2+) uptake capacity correlated with an increase in the amount of mutant huntingtin protein (mHtt) associated with mitochondria from 12-month-old YAC128 mice. We speculate that this may happen because of mHtt-mediated sequestration of free fatty acids thereby increasing resistance of mitochondria to Ca(2+)-induced damage. In experiments with striatal neurons from YAC128 and FVB/NJ mice, brief exposure to 25 or 100 μM glutamate produced transient elevations in cytosolic Ca(2+) followed by recovery to near resting levels. Following recovery of cytosolic Ca(2+), mitochondrial depolarization with FCCP produced comparable elevations in cytosolic Ca(2+), suggesting similar Ca(2+) release and, consequently, Ca(2+) loads in neuronal mitochondria from YAC128 and FVB/NJ mice. Together, our data argue against a detrimental effect of mHtt on Ca(2+) handling in brain mitochondria of YAC128 mice. We demonstrate that mutant huntingtin (mHtt) binds to brain synaptic and nonsynaptic mitochondria and the amount of mitochondria-bound mHtt correlates with increased mitochondrial Ca(2+) uptake capacity. We propose that this may happen due to mHtt-mediated sequestration of free fatty acids thereby increasing resistance of mitochondria to Ca(2+)-induced damage. PMID:25963273

  11. Proteome, Phosphoproteome, and Hydroxyproteome of Liver Mitochondria in Diabetic Rats at Early Pathogenic Stages*

    PubMed Central

    Deng, Wen-Jun; Nie, Song; Dai, Jie; Wu, Jia-Rui; Zeng, Rong

    2010-01-01

    It has been proposed that mitochondrial dysfunction is involved in the pathogenesis of type 2 diabetes (T2D). To dissect the underlying mechanisms, we performed a multiplexed proteomics study on liver mitochondria isolated from a spontaneous diabetic rat model before/after they were rendered diabetic. Altogether, we identified 1091 mitochondrial proteins, 228 phosphoproteins, and 355 hydroxyproteins. Mitochondrial proteins were found to undergo expression changes in a highly correlated fashion during T2D development. For example, proteins involved in β-oxidation, the tricarboxylic acid cycle, oxidative phosphorylation, and other bioenergetic processes were coordinately up-regulated, indicating that liver cells confronted T2D by increasing energy expenditure and activating pathways that rid themselves of the constitutively increased flux of glucose and lipid. Notably, activation of oxidative phosphorylation was immediately related to the overproduction of reactive oxygen species, which caused oxidative stress within the cells. Increased oxidative stress was also evidenced by our post-translational modification profiles such that mitochondrial proteins were more heavily hydroxylated during T2D development. Moreover, we observed a distinct depression of antiapoptosis and antioxidative stress proteins that might reflect a higher apoptotic index under the diabetic stage. We suggest that such changes in systematic metabolism were causally linked to the development of T2D. Comparing proteomics data against microarray data, we demonstrated that many T2D-related alterations were unidentifiable by either proteomics or genomics approaches alone, underscoring the importance of integrating different approaches. Our compendium could help to unveil pathogenic events in mitochondria leading to T2D and be useful for the discovery of diagnosis biomarker and therapeutic targets of T2D. PMID:19700791

  12. Brain cholinergic impairment in liver failure.

    PubMed

    García-Ayllón, María-Salud; Cauli, Omar; Silveyra, María-Ximena; Rodrigo, Regina; Candela, Asunción; Compañ, Antonio; Jover, Rodrigo; Pérez-Mateo, Miguel; Martínez, Salvador; Felipo, Vicente; Sáez-Valero, Javier

    2008-11-01

    The cholinergic system is involved in specific behavioural responses and cognitive processes. Here, we examined potential alterations in the brain levels of key cholinergic enzymes in cirrhotic patients and animal models with liver failure. An increase (~30%) in the activity of the acetylcholine-hydrolyzing enzyme, acetylcholinesterase (AChE) is observed in the brain cortex from patients deceased from hepatic coma, while the activity of the acetylcholine-synthesizing enzyme, choline acetyltransferase, remains unaffected. In agreement with the human data, AChE activity in brain cortical extracts of bile duct ligated (BDL) rats was increased (~20%) compared to controls. A hyperammonemic diet did not result in any further increase of AChE levels in the BDL model, and no change was observed in hyperammonemic diet rats without liver disease. Portacaval shunted rats which display increased levels of cerebral ammonia did not show any brain cholinergic abnormalities, confirming that high ammonia levels do not play a role in brain AChE changes. A selective increase of tetrameric AChE, the major AChE species involved in hydrolysis of acetylcholine in the brain, was detected in both cirrhotic humans and BDL rats. Histological examination of BDL and non-ligated rat brains shows that the subcellular localization of both AChE and choline acetyltransferase, and thus the accessibility to their substrates, appears unaltered by the pathological condition. The BDL-induced increase in AChE activity was not parallelled by an increase in mRNA levels. Increased AChE in BDL cirrhotic rats leads to a pronounced decrease (~50-60%) in the levels of acetylcholine. Finally, we demonstrate that the AChE inhibitor rivastigmine is able to improve memory deficits in BDL rats. One week treatment with rivastigmine (0.6 mg/kg; once a day, orally, for a week) resulted in a 25% of inhibition in the enzymatic activity of AChE with no change in protein composition, as assessed by sucrose density gradient

  13. Brain cholinergic impairment in liver failure

    PubMed Central

    García-Ayllón, María-Salud; Cauli, Omar; Silveyra, María-Ximena; Rodrigo, Regina; Candela, Asunción; Compañ, Antonio; Jover, Rodrigo; Pérez-Mateo, Miguel; Martínez, Salvador; Felipo, Vicente

    2008-01-01

    The cholinergic system is involved in specific behavioural responses and cognitive processes. Here, we examined potential alterations in the brain levels of key cholinergic enzymes in cirrhotic patients and animal models with liver failure. An increase (∼30%) in the activity of the acetylcholine-hydrolyzing enzyme, acetylcholinesterase (AChE) is observed in the brain cortex from patients deceased from hepatic coma, while the activity of the acetylcholine-synthesizing enzyme, choline acetyltransferase, remains unaffected. In agreement with the human data, AChE activity in brain cortical extracts of bile duct ligated (BDL) rats was increased (∼20%) compared to controls. A hyperammonemic diet did not result in any further increase of AChE levels in the BDL model, and no change was observed in hyperammonemic diet rats without liver disease. Portacaval shunted rats which display increased levels of cerebral ammonia did not show any brain cholinergic abnormalities, confirming that high ammonia levels do not play a role in brain AChE changes. A selective increase of tetrameric AChE, the major AChE species involved in hydrolysis of acetylcholine in the brain, was detected in both cirrhotic humans and BDL rats. Histological examination of BDL and non-ligated rat brains shows that the subcellular localization of both AChE and choline acetyltransferase, and thus the accessibility to their substrates, appears unaltered by the pathological condition. The BDL-induced increase in AChE activity was not parallelled by an increase in mRNA levels. Increased AChE in BDL cirrhotic rats leads to a pronounced decrease (∼50–60%) in the levels of acetylcholine. Finally, we demonstrate that the AChE inhibitor rivastigmine is able to improve memory deficits in BDL rats. One week treatment with rivastigmine (0.6 mg/kg; once a day, orally, for a week) resulted in a 25% of inhibition in the enzymatic activity of AChE with no change in protein composition, as assessed by sucrose density

  14. Depleted uranium induces disruption of energy homeostasis and oxidative stress in isolated rat brain mitochondria.

    PubMed

    Shaki, Fatemeh; Hosseini, Mir-Jamal; Ghazi-Khansari, Mahmoud; Pourahmad, Jalal

    2013-06-01

    Depleted uranium (DU) is emerging as an environmental pollutant primarily due to its military applications. Gulf War veterans with embedded DU showed cognitive disorders that suggest that the central nervous system is a target of DU. Recent evidence has suggested that DU could induce oxidative stress and mitochondrial dysfunction in brain tissue. However, the underlying mechanisms of DU toxicity in brain mitochondria are not yet well understood. Brain mitochondria were obtained using differential centrifugation and were incubated with different concentrations (50, 100 and 200 μM) of uranyl acetate (UA) as a soluble salt of U(238) for 1 h. In this research, mitochondrial ROS production, collapse of mitochondrial membrane potential and mitochondrial swelling were examined by flow cytometry following the addition of UA. Meanwhile, mitochondrial sources of ROS formation were determined using specific substrates and inhibitors. Complex II and IV activity and also the extent of lipid peroxidation and glutathione (GSH) oxidation were detected via spectroscopy. Furthermore, we investigated the concentration of ATP and ATP/ADP ratio using luciferase enzyme and cytochrome c release from mitochondria which was detected by ELISA kit. UA caused concentration-dependent elevation of succinate-linked mitochondrial ROS production, lipid peroxidation, GSH oxidation and inhibition of mitochondrial complex II. UA also induced mitochondrial permeability transition, ATP production decrease and increase in cytochrome c release. Pre-treatment with antioxidants significantly inhibited all the above mentioned toxic effects of UA. This study suggests that mitochondrial oxidative stress and impairment of oxidative phosphorylation in brain mitochondria may play a key role in DU neurotoxicity as reported in Gulf War Syndrome. PMID:23629690

  15. The Responses of Tissues from the Brain, Heart, Kidney, and Liver to Resuscitation following Prolonged Cardiac Arrest by Examining Mitochondrial Respiration in Rats

    PubMed Central

    Kim, Junhwan; Perales Villarroel, José Paul; Zhang, Wei; Yin, Tai; Shinozaki, Koichiro; Hong, Angela; Lampe, Joshua W.; Becker, Lance B.

    2016-01-01

    Cardiac arrest induces whole-body ischemia, which causes damage to multiple organs. Understanding how each organ responds to ischemia/reperfusion is important to develop better resuscitation strategies. Because direct measurement of organ function is not practicable in most animal models, we attempt to use mitochondrial respiration to test efficacy of resuscitation on the brain, heart, kidney, and liver following prolonged cardiac arrest. Male Sprague-Dawley rats are subjected to asphyxia-induced cardiac arrest for 30 min or 45 min, or 30 min cardiac arrest followed by 60 min cardiopulmonary bypass resuscitation. Mitochondria are isolated from brain, heart, kidney, and liver tissues and examined for respiration activity. Following cardiac arrest, a time-dependent decrease in state-3 respiration is observed in mitochondria from all four tissues. Following 60 min resuscitation, the respiration activity of brain mitochondria varies greatly in different animals. The activity after resuscitation remains the same in heart mitochondria and significantly increases in kidney and liver mitochondria. The result shows that inhibition of state-3 respiration is a good marker to evaluate the efficacy of resuscitation for each organ. The resulting state-3 respiration of brain and heart mitochondria following resuscitation reenforces the need for developing better strategies to resuscitate these critical organs following prolonged cardiac arrest. PMID:26770657

  16. 2-Methylcitric acid impairs glutamate metabolism and induces permeability transition in brain mitochondria.

    PubMed

    Amaral, Alexandre Umpierrez; Cecatto, Cristiane; Castilho, Roger Frigério; Wajner, Moacir

    2016-04-01

    Accumulation of 2-methylcitric acid (2MCA) is observed in methylmalonic and propionic acidemias, which are clinically characterized by severe neurological symptoms. The exact pathogenetic mechanisms of brain abnormalities in these diseases are poorly established and very little has been reported on the role of 2MCA. In the present work we found that 2MCA markedly inhibited ADP-stimulated and uncoupled respiration in mitochondria supported by glutamate, with a less significant inhibition in pyruvate plus malate respiring mitochondria. However, no alterations occurred when α-ketoglutarate or succinate was used as respiratory substrates, suggesting a defect on glutamate oxidative metabolism. It was also observed that 2MCA decreased ATP formation in glutamate plus malate or pyruvate plus malate-supported mitochondria. Furthermore, 2MCA inhibited glutamate dehydrogenase activity at concentrations as low as 0.5 mM. Kinetic studies revealed that this inhibitory effect was competitive in relation to glutamate. In contrast, assays of osmotic swelling in non-respiring mitochondria suggested that 2MCA did not significantly impair mitochondrial glutamate transport. Finally, 2MCA provoked a significant decrease in mitochondrial membrane potential and induced swelling in Ca(2+)-loaded mitochondria supported by different substrates. These effects were totally prevented by cyclosporine A plus ADP or ruthenium red, indicating induction of mitochondrial permeability transition. Taken together, our data strongly indicate that 2MCA behaves as a potent inhibitor of glutamate oxidation by inhibiting glutamate dehydrogenase activity and as a permeability transition inducer, disturbing mitochondrial energy homeostasis. We presume that 2MCA-induced mitochondrial deleterious effects may contribute to the pathogenesis of brain damage in patients affected by methylmalonic and propionic acidemias. We propose that brain glutamate oxidation is disturbed by 2-methylcitric acid (2MCA), which

  17. The mitochondria-targeted antioxidant MitoQ attenuates liver fibrosis in mice

    PubMed Central

    Rehman, Hasibur; Liu, Qinlong; Krishnasamy, Yasodha; Shi, Zengdun; Ramshesh, Venkat K; Haque, Khujista; Schnellmann, Rick G; Murphy, Michael P; Lemasters, John J; Rockey, Don C; Zhong, Zhi

    2016-01-01

    Oxidative stress plays an essential role in liver fibrosis. This study investigated whether MitoQ, an orally active mitochondrial antioxidant, decreases liver fibrosis. Mice were injected with corn oil or carbon tetrachloride (CCl4, 1:3 dilution in corn oil; 1 µl/g, ip) once every 3 days for up to 6 weeks. 4-Hydroxynonenal adducts increased markedly after CCl4 treatment, indicating oxidative stress. MitoQ attenuated oxidative stress after CCl4. Collagen 1α1 mRNA and hydroxyproline increased markedly after CCl4 treatment, indicating increased collagen formation and deposition. CCl4 caused overt pericentral fibrosis as revealed by both the sirius red staining and second harmonic generation microscopy. MitoQ blunted fibrosis after CCl4. Profibrotic transforming growth factor-β1 (TGF-β1) mRNA and expression of smooth muscle α-actin, an indicator of hepatic stellate cell (HSC) activation, increased markedly after CCl4 treatment. Smad 2/3, the major mediator of TGF-β fibrogenic effects, was also activated after CCl4 treatment. MitoQ blunted HSC activation, TGF-β expression, and Smad2/3 activation after CCl4 treatment. MitoQ also decreased necrosis, apoptosis and inflammation after CCl4 treatment. In cultured HSCs, MitoQ decreased oxidative stress, inhibited HSC activation, TGF-β1 expression, Smad2/3 activation, and extracellular signal-regulated protein kinase activation. Taken together, these data indicate that mitochondrial reactive oxygen species play an important role in liver fibrosis and that mitochondria-targeted antioxidants are promising potential therapies for prevention and treatment of liver fibrosis. PMID:27186319

  18. The mitochondria-targeted antioxidant MitoQ attenuates liver fibrosis in mice.

    PubMed

    Rehman, Hasibur; Liu, Qinlong; Krishnasamy, Yasodha; Shi, Zengdun; Ramshesh, Venkat K; Haque, Khujista; Schnellmann, Rick G; Murphy, Michael P; Lemasters, John J; Rockey, Don C; Zhong, Zhi

    2016-01-01

    Oxidative stress plays an essential role in liver fibrosis. This study investigated whether MitoQ, an orally active mitochondrial antioxidant, decreases liver fibrosis. Mice were injected with corn oil or carbon tetrachloride (CCl4, 1:3 dilution in corn oil; 1 µl/g, ip) once every 3 days for up to 6 weeks. 4-Hydroxynonenal adducts increased markedly after CCl4 treatment, indicating oxidative stress. MitoQ attenuated oxidative stress after CCl4. Collagen 1α1 mRNA and hydroxyproline increased markedly after CCl4 treatment, indicating increased collagen formation and deposition. CCl4 caused overt pericentral fibrosis as revealed by both the sirius red staining and second harmonic generation microscopy. MitoQ blunted fibrosis after CCl4. Profibrotic transforming growth factor-β1 (TGF-β1) mRNA and expression of smooth muscle α-actin, an indicator of hepatic stellate cell (HSC) activation, increased markedly after CCl4 treatment. Smad 2/3, the major mediator of TGF-β fibrogenic effects, was also activated after CCl4 treatment. MitoQ blunted HSC activation, TGF-β expression, and Smad2/3 activation after CCl4 treatment. MitoQ also decreased necrosis, apoptosis and inflammation after CCl4 treatment. In cultured HSCs, MitoQ decreased oxidative stress, inhibited HSC activation, TGF-β1 expression, Smad2/3 activation, and extracellular signal-regulated protein kinase activation. Taken together, these data indicate that mitochondrial reactive oxygen species play an important role in liver fibrosis and that mitochondria-targeted antioxidants are promising potential therapies for prevention and treatment of liver fibrosis. PMID:27186319

  19. Proteomic analysis of mitochondria from embryonic and postnatal rat brains reveals response to developmental changes in energy demands

    PubMed Central

    Villeneuve, Lance M.; Stauch, Kelly L.; Fox, Howard S.

    2014-01-01

    Many biological processes converge on the mitochondria. In such systems, where many pathways converge, manipulation of the components can produce varied and far-reaching effects. Due to the centrality of the mitochondria in many cellular pathways, we decided to investigate the brain mitochondrial proteome during early development. Using a SWATH mass spectrometry-based technique, we were able to identify vast proteomic alterations between whole brain mitochondria from rats at embryonic day 18 compared to postnatal day 7. These findings include statistically significant alterations in proteins involved in glycolysis and mitochondrial trafficking/dynamics. Additionally, bioinformatic analysis enabled the identification of HIF1A and XBP1 as upstream transcriptional regulators of many of the differentially expressed proteins. These data suggest that the cell is rearranging mitochondria to accommodate special energy demands and that cytosolic proteins exert mitochondrial effects through dynamic interactions with mitochondria. PMID:25046836

  20. The influence of hypothyroidism on the transport of phosphate and on the lipid composition in rat-liver mitochondria.

    PubMed

    Paradies, G; Ruggiero, F M; Dinoi, P

    1991-11-18

    The influence of hypothyroidism on the transport of phosphate and on the lipid composition in rat-liver mitochondria was examined. It was found that the rate of phosphate transport is reduced (around 40%) in mitochondria from hypothyroid rats compared to that obtained in mitochondria from normal rats. Treatment of hypothyroid rats with thyroid hormone reverses this effect completely. Kinetic analysis of the phosphate transport indicates that only the Vmax of this process is affected, while there is no change in the Km values. The lower rate of phosphate transport in mitochondria from hypothyroid rats is also demonstrated by swelling experiments. There is no significant difference either in the respiratory control ratios or in the ADP/O ratios between these two types of mitochondria. The hepatic mitochondrial lipid composition is altered significantly in hypothyroid rats. The total cholesterol increases, the phospholipids decrease and the cholesterol/phospholipid molar ratio increases (around 40%). Among the phospholipids, cardiolipin shows the greatest alteration (30% decrease in the hypothyroid rats). The phosphatidylethanolamine/phosphatidylcholine ratio also decreases. Alterations were also found in the pattern of fatty acids. These changes in lipid composition may be responsible, at least in part, for the depression of the phosphate carrier activity in mitochondria from hypothyroid rats. PMID:1751524

  1. Prediction of Liver Injury Induced by Chemicals in Human With a Multiparametric Assay on Isolated Mouse Liver Mitochondria

    PubMed Central

    Porceddu, Mathieu; Buron, Nelly; Borgne-Sanchez, Annie

    2012-01-01

    Drug-induced liver injury (DILI) in humans is difficult to predict using classical in vitro cytotoxicity screening and regulatory animal studies. This explains why numerous compounds are stopped during clinical trials or withdrawn from the market due to hepatotoxicity. Thus, it is important to improve early prediction of DILI in human. In this study, we hypothesized that this goal could be achieved by investigating drug-induced mitochondrial dysfunction as this toxic effect is a major mechanism of DILI. To this end, we developed a high-throughput screening platform using isolated mouse liver mitochondria. Our broad spectrum multiparametric assay was designed to detect the global mitochondrial membrane permeabilization (swelling), inner membrane permeabilization (transmembrane potential), outer membrane permeabilization (cytochrome c release), and alteration of mitochondrial respiration driven by succinate or malate/glutamate. A pool of 124 chemicals (mainly drugs) was selected, including 87 with documented DILI and 37 without reported clinical hepatotoxicity. Our screening assay revealed an excellent sensitivity for clinical outcome of DILI (94 or 92% depending on cutoff) and a high positive predictive value (89 or 82%). A highly significant relationship between drug-induced mitochondrial toxicity and DILI occurrence in patients was calculated (p < 0.001). Moreover, this multiparametric assay allowed identifying several compounds for which mitochondrial toxicity had never been described before and even helped to clarify mechanisms with some drugs already known to be mitochondriotoxic. Investigation of drug-induced loss of mitochondrial integrity and function with this multiparametric assay should be considered for integration into basic screening processes at early stage to select drug candidates with lower risk of DILI in human. This assay is also a valuable tool for assessing the mitochondrial toxicity profile and investigating the mechanism of action of new

  2. The effect of diet on the fatty acid compositions of serum, brain, brain mitochondria and myelin in the rat

    PubMed Central

    Rathbone, L.

    1965-01-01

    1. Three groups of female rats (8–12 weeks old) were maintained respectively on a linoleic acid-rich diet, a linoleic acid-poor predominantly saturated-fatty acid diet and a normal diet. Changes in the fatty acid compositions of serum, brain, brain mitochondria-rich fraction and myelin were observed. 2. Of the serum fatty acids, linoleic acid showed the greatest change in the percentage of the total acids in response to diet; the change in the proportion of oleic acid was considerable. The percentages of arachidonic acid in serum fatty acids in the groups on the linoleic acid-rich and linoleic acid-poor diets were similar, but higher than those in the normal group. 3. Changes in the proportions of linoleic acid, arachidonic acid and docosahexaenoic acid occurred in brain fatty acids that to some extent paralleled those occurring in the serum. Changes in the proportions of most other acids in the serum fatty acids were not accompanied by corresponding changes in the brain fatty acids. 4. The percentage fatty acid compositions of a mitochondria-rich fraction and myelin are given, and changes in the relative proportions of linoleic acid, arachidonic acid and possibly some docosapolyenoic acids were demonstrated to occur as a result of diet. 5. The results are discussed in relation to the possible aetiology of multiple sclerosis. PMID:5881652

  3. Evidence for resveratrol-induced preservation of brain mitochondria functions after hypoxia-reoxygenation.

    PubMed

    Morin, C; Zini, R; Albengres, E; Bertelli, A A E; Bertelli, A; Tillement, J P

    2003-01-01

    We have previously shown, as have other authors, that trans-resveratrol (E-resveratrol, 3,4,5-trihydroxy-E-stilbene) reduces reactive oxygen species (ROS) generation of mitochondria freshly isolated from healthy rat brains and that it also counteracts the effect of uncouplers (CCCP) on mitochondrial respiration and oxidative phosphorylation. Two main mechanisms have been shown: firstly, a scavenger effect toward O2- and secondly inhibition of complex III ROS generation. We now report on the effects of resveratrol in a pathological model that mimics the ischemia followed by the reperfusion process which may occur in the human brain. Isolated brain mitochondria were submitted first to hypoxia then to reoxygenation. The aim of this study was to determine the extent of mitochondrial damage induced by this experimental model, to demonstrate which mitochondrial functions were altered and to quantify the extent to which they were prevented by resveratrol. Resveratrol was either added to mitochondria freshly isolated from healthy rat brains or was injected by subcutaneous chronically implanted pumps (0.5, 2 and 10 mg/kg/day for 7 days). The rats were then sacrificed and mitochondria were extracted from brains. To evaluate the respective effects of hypoxia and reoxygenation on mitochondrial functions and the relevant effects of resveratrol, this drug was added (first protocol) either before the complete process (i.e., hypoxia and reoxygenation), or after anoxia before reoxygenation. We found that resveratrol prevented alterations of mitochondrial functions. This substance partly counteracted the decrease in respiratory control and the increase in ROS generation. It fully inhibited the alteration of membrane fluidity and the mitochondrial step of the apoptotic process (evidenced by cytochrome c release and membrane potential collapse). The effects of resveratrol were concentration-dependent (in vitro) or dose-dependent (ex vivo, second protocol). They were not significantly

  4. On the mechanism(s) of membrane permeability transition in liver mitochondria of lamprey, Lampetra fluviatilis L.: insights from cadmium.

    PubMed

    Belyaeva, Elena A; Emelyanova, Larisa V; Korotkov, Sergey M; Brailovskaya, Irina V; Savina, Margarita V

    2014-01-01

    Previously we have shown that opening of the mitochondrial permeability transition pore in its low conductance state is the case in hepatocytes of the Baltic lamprey (Lampetra fluviatilis L.) during reversible metabolic depression taking place in the period of its prespawning migration when the exogenous feeding is switched off. The depression is observed in the last year of the lamprey life cycle and is conditioned by reversible mitochondrial dysfunction (mitochondrial uncoupling in winter and coupling in spring). To further elucidate the mechanism(s) of induction of the mitochondrial permeability transition pore in the lamprey liver, we used Cd(2+) and Ca(2+) plus Pi as the pore inducers. We found that Ca(2+) plus Pi induced the high-amplitude swelling of the isolated "winter" mitochondria both in isotonic sucrose and ammonium nitrate medium while both low and high Cd(2+) did not produce the mitochondrial swelling in these media. Low Cd(2+) enhanced the inhibition of basal respiration rate of the "winter" mitochondria energized by NAD-dependent substrates whereas the same concentrations of the heavy metal evoked its partial stimulation on FAD-dependent substrates. The above changes produced by Cd(2+) or Ca(2+) plus Pi in the "winter" mitochondria were only weakly (if so) sensitive to cyclosporine A (a potent pharmacological desensitizer of the nonselective pore) added alone and they were not sensitive to dithiothreitol (a dithiol reducing agent). Under monitoring of the transmembrane potential of the "spring" lamprey liver mitochondria, we revealed that Cd(2+) produced its decrease on both types of the respiratory substrates used that was strongly hampered by cyclosporine A, and the membrane potential was partially restored by dithiothreitol. The effects of different membrane permeability modulators on the lamprey liver mitochondria function and the seasonal changes in their action are discussed. PMID:24995321

  5. On the Mechanism(s) of Membrane Permeability Transition in Liver Mitochondria of Lamprey, Lampetra fluviatilis L.: Insights from Cadmium

    PubMed Central

    Belyaeva, Elena A.; Emelyanova, Larisa V.; Korotkov, Sergey M.; Brailovskaya, Irina V.; Savina, Margarita V.

    2014-01-01

    Previously we have shown that opening of the mitochondrial permeability transition pore in its low conductance state is the case in hepatocytes of the Baltic lamprey (Lampetra fluviatilis L.) during reversible metabolic depression taking place in the period of its prespawning migration when the exogenous feeding is switched off. The depression is observed in the last year of the lamprey life cycle and is conditioned by reversible mitochondrial dysfunction (mitochondrial uncoupling in winter and coupling in spring). To further elucidate the mechanism(s) of induction of the mitochondrial permeability transition pore in the lamprey liver, we used Cd2+ and Ca2+ plus Pi as the pore inducers. We found that Ca2+ plus Pi induced the high-amplitude swelling of the isolated “winter” mitochondria both in isotonic sucrose and ammonium nitrate medium while both low and high Cd2+ did not produce the mitochondrial swelling in these media. Low Cd2+ enhanced the inhibition of basal respiration rate of the “winter” mitochondria energized by NAD-dependent substrates whereas the same concentrations of the heavy metal evoked its partial stimulation on FAD-dependent substrates. The above changes produced by Cd2+ or Ca2+ plus Pi in the “winter” mitochondria were only weakly (if so) sensitive to cyclosporine A (a potent pharmacological desensitizer of the nonselective pore) added alone and they were not sensitive to dithiothreitol (a dithiol reducing agent). Under monitoring of the transmembrane potential of the “spring” lamprey liver mitochondria, we revealed that Cd2+ produced its decrease on both types of the respiratory substrates used that was strongly hampered by cyclosporine A, and the membrane potential was partially restored by dithiothreitol. The effects of different membrane permeability modulators on the lamprey liver mitochondria function and the seasonal changes in their action are discussed. PMID:24995321

  6. Entry and exit pathways of CO2 in rat liver mitochondria respiring in a bicarbonate buffer system.

    PubMed

    Balboni, E; Lehninger, A L

    1986-03-15

    The dynamics and pathways of CO2 movements across the membranes of mitochondria respiring in vitro in a CO2/HCO-3 buffer at concentrations close to that in intact rat tissues were continuously monitored with a gas-permeable CO2-sensitive electrode. O2 uptake and pH changes were monitored simultaneously. Factors affecting CO2 entry were examined under conditions in which CO2 uptake was coupled to electrophoretic influx of K+ (in the presence of valinomycin) or Ca2+. The role of mitochondrial carbonic anhydrase (EC 4.2.1.1) in CO2 entry was evaluated by comparison of CO2 uptake by rat liver mitochondria, which possess carbonic anhydrase, versus rat heart mitochondria, which lack carbonic anhydrase. Such studies showed that matrix carbonic anhydrase activity is essential for rapid net uptake of CO2 with K+ or Ca2+. Studies with acetazolamide (Diamox), a potent inhibitor of carbonic anhydrase, confirmed the requirement of matrix carbonic anhydrase for net CO2 uptake. It was shown that at pH 7.2 the major species leaving respiring mitochondria is dissolved CO2, rather than HCO-3 or H2CO3 suggested by earlier reports. Efflux of endogenous CO2/HCO-3 is significantly inhibited by inhibitors of the dicarboxylate and tricarboxylate transport systems of the rat liver inner membrane. The possibility that these anion carriers mediate outward transport of HCO-3 is discussed. PMID:3081508

  7. The metabolism of menadione impairs the ability of rat liver mitochondria to take up and retain calcium.

    PubMed

    Bellomo, G; Jewell, S A; Orrenius, S

    1982-10-10

    The ability of mitochondria to take up and retain Ca2+, and thereby to effect the free intracellular concentration of this ion, is well established. More recently, it has been reported (Lehninger, A. L., Vercesi, A., and Bababunmi, E. A. (1978) Proc. Natl. Acad. Sci. U. S. A. 75, 1690-1696) that the redox state of pyridine nucleotides modulates mitochondrial Ca2+ balance, since the oxidation of mitochondrial NAD(P)H is associated with the release of Ca2+ from these organelles. The latter may be achieved by a variety of treatments including the incubation of Ca2+-loaded liver mitochondria with hydroperoxides, the metabolism of which by the glutathione peroxidase-glutathione reductase system results in NADPH consumption. The metabolism of menadione (2-methyl-1,4-naphthoquinone) by Ca2+-loaded rat liver mitochondria results in rapid oxidation and loss of pyridine nucleotides and a decrease in ATP level. It is also associated with Ca2+ release and an impaired ability of the mitochondria to take up and retain Ca2+. The effects of menadione on mitochondrial Ca2+ balance are more rapid and pronounced than those of t-butylhydroperoxide, and in contrast to those observed with the hydroperoxide, they are not abolished by pretreatment with a glutathione-depleting agent. The effects of menadione on Ca2+ homeostasis are probably initiated by NAD(P)H oxidation linked to the reduction of menadione by both NADH-ubiquinone oxidoreductase and NAD(P)H:(quinone-acceptor) oxidoreductase. PMID:7118897

  8. 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine inhibits proton motive force in energized liver mitochondria

    SciTech Connect

    Singh, Y.; Bhatnagar, R.; Sidhu, G.S.; Batra, J.K.; Krishna, G. )

    1989-05-15

    It is known that 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), which induces Parkinson's-like disease in primates and humans, depletes hepatocytes of ATP and subsequently causes cell death. Incubation of rat liver mitochondria with MPTP and 1-methyl-4-phenyl pyridinium ion (MPP+) significantly inhibited incorporation of {sup 32}Pi into ATP. MPTP and MPP+ inhibited the development of membrane potential and pH gradient in energized rat liver mitochondria, suggesting that reduction of the proton motive force may have reduced ATP synthesis. Since deprenyl, an inhibitor of monoamine oxidase, prevented the formation of MPP+ and inhibited the decrease in membrane potential caused by MPTP, but not that caused by MPP+, these effects of MPTP, as well as cell death, probably were mediated by MPP+. This mechanism may play a role in the specific loss of dopaminergic neurons resulting in MPTP-induced Parkinson's disease.

  9. Ultrastructural mitochondria changes in perihematomal brain and neuroprotective effects of Huperzine A after acute intracerebral hemorrhage

    PubMed Central

    Lu, Haiying; Jiang, Mei; Lu, Lei; Zheng, Guo; Dong, Qiang

    2015-01-01

    Aim The purpose of the study was to observe the ultrastructural changes of neuronal mitochondria in perihematomal brain tissue and assess the therapeutic potential of Huperzine A (HA, a mitochondrial protector) following intracerebral hemorrhage (ICH). Methods Brain hemorrhage was induced in adult Sprague Dawley rats by injecting autologous blood into the striatum and then removing the brains 3, 6, 12, 24, or 48 hours later to analyze mitochondrial ultrastructure in a blinded manner. Parallel groups of ICH rats were treated with HA or saline immediately after ICH. Perihematomal apoptosis was determined by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL), caspase-3 activation and cytochrome C translocation were tracked by immunoblots, and neurobehavioral test results were compared between the groups. Results Mitochondria in perihematomal neurons demonstrated dramatic changes including mitochondrial swelling, intracristal dilation, and decreased matrix density. HA treatment decreased mitochondrial injury and apoptosis, inhibited caspase-3 activation and cytochrome C translocation, and improved behavioral recovery. Conclusion These data show that ICH induces dramatic mitochondrial damage, and HA exhibits protective effects possibly through ameliorating mitochondrial injury and apoptosis. Collectively, these findings suggest a new direction for novel therapeutics. PMID:26508860

  10. Death receptor and mitochondria-mediated hepatocyte apoptosis underlies liver dysfunction in rats exposed to organic pollutants from drinking water

    PubMed Central

    Yang, Guanghong; Zhou, Zhiwei; Cen, Yanli; Gui, Xiaolin; Zeng, Qibing; Ao, Yunxia; Li, Qian; Wang, Shiran; Li, Jun; Zhang, Aihua

    2015-01-01

    Persistent organic pollutants in drinking water impose a substantial risk to the health of human beings, but the evidence for liver toxic effect and the underlying mechanism is scarce. This study aimed to examine the liver toxicity and elucidate the molecular mechanism of organic pollutants in drinking water in normal human liver cell line L02 cells and rats. The data showed that organic extraction from drinking water remarkably impaired rat liver function, evident from the increase in the serum level of alanine aminotransferase, aspartate aminotransferase, and cholinesterase, and decrease in the serum level of total protein and albumin. Organic extraction dose-dependently induced apoptotic cell death in rat liver and L02 cells. Administration of rats with organic extraction promoted death receptor signaling pathway through the increase in gene and protein expression level of Fas and FasL. Treatment of rats with organic extraction also induced mitochondria-mediated apoptosis via increasing the expression level of proapoptotic protein, Bax, but decreasing the expression level of antiapoptotic protein, Bcl-2, resulting in an upregulation of cytochrome c and activation of caspase cascade at both transcriptional and post-transcriptional levels. Moreover, organic extraction enhanced rat liver glutathione S-transferases activity and reactive oxygen species generation, and upregulated aryl hydrocarbon receptor and glutathione S-transferase A1 at both transcriptional and translational levels. Collectively, the results indicate that organic extraction from drinking water impairs liver function, with the involvement of death receptor and mitochondria-mediated apoptosis in rats. The results provide evidence and molecular mechanisms for organic pollutants in drinking water-induced liver dysfunction, which may help prevent and treat organic extraction-induced liver injury. PMID:26316710

  11. Death receptor and mitochondria-mediated hepatocyte apoptosis underlies liver dysfunction in rats exposed to organic pollutants from drinking water.

    PubMed

    Yang, Guanghong; Zhou, Zhiwei; Cen, Yanli; Gui, Xiaolin; Zeng, Qibing; Ao, Yunxia; Li, Qian; Wang, Shiran; Li, Jun; Zhang, Aihua

    2015-01-01

    Persistent organic pollutants in drinking water impose a substantial risk to the health of human beings, but the evidence for liver toxic effect and the underlying mechanism is scarce. This study aimed to examine the liver toxicity and elucidate the molecular mechanism of organic pollutants in drinking water in normal human liver cell line L02 cells and rats. The data showed that organic extraction from drinking water remarkably impaired rat liver function, evident from the increase in the serum level of alanine aminotransferase, aspartate aminotransferase, and cholinesterase, and decrease in the serum level of total protein and albumin. Organic extraction dose-dependently induced apoptotic cell death in rat liver and L02 cells. Administration of rats with organic extraction promoted death receptor signaling pathway through the increase in gene and protein expression level of Fas and FasL. Treatment of rats with organic extraction also induced mitochondria-mediated apoptosis via increasing the expression level of proapoptotic protein, Bax, but decreasing the expression level of antiapoptotic protein, Bcl-2, resulting in an upregulation of cytochrome c and activation of caspase cascade at both transcriptional and post-transcriptional levels. Moreover, organic extraction enhanced rat liver glutathione S-transferases activity and reactive oxygen species generation, and upregulated aryl hydrocarbon receptor and glutathione S-transferase A1 at both transcriptional and translational levels. Collectively, the results indicate that organic extraction from drinking water impairs liver function, with the involvement of death receptor and mitochondria-mediated apoptosis in rats. The results provide evidence and molecular mechanisms for organic pollutants in drinking water-induced liver dysfunction, which may help prevent and treat organic extraction-induced liver injury. PMID:26316710

  12. Divalent phosphate is a counterion for carboxyatractyloside-insensitive adenine nucleotide transport in rat liver mitochondria

    SciTech Connect

    Nosek, M.T.; Aprille, J.R.

    1986-05-01

    Unidirectional, carboxyatractyloside(CAT)-insensitive adenine nucleotide (AdN) fluxes have been studied in isolated rat liver mitochondria (mito). Previous work has shown that ATP x Mg transport in one direction is coupled to ATP x Mg or P/sub i/ transport in the opposite direction. The purpose of this study was to determine whether divalent HPO/sub 4//sup 2 -/ or monovalent H/sub 2/PO/sub 4//sup -/ is the transported phosphate species. The authors used the monofluorophosphate (PO/sub 3/F/sup 2 -/) and difluorophosphate (PO/sub 2/F/sub 2//sup -/) analogues as potential counterions forAdN efflux. After a preincubation on ice with /sup 14/C-ADP to label the matrix AdN, efflux was measured at 30/sup 0/C, pH 7.4, in 225mM sucrose, 10mM KCl, 5mM MgCl/sub 2/, 5mM glutamate, 5mM malate, 10mM Tris, 0.5mM P/sub i/, 1mM ATP, and 5..mu..M CAT. With no other additions efflux was -0.62 +/- 0.20 nmole/minute/mg protein. The data supports the hypothesis that divalent but not monovalent phosphate can act as a counterion for ATPx Mg transport over this CAT-insensitive carrier.

  13. Thyroidal regulation of substrate kinetics properties of cytochrome oxidase in rat liver mitochondria.

    PubMed

    Modi, Hiren R; Katyare, Surendra S; Patel, Samir P

    2008-07-01

    Effects of thyroidectomy (T(x)) and subsequent treatment with 3,5,3'-triiodothyronine (T(3)), and combined treatment (T(R)) with T(3) + thyroxine (T(4)) on substrate kinetics properties of cytochrome oxidase of rat liver mitochondria were examined. T(x) resulted in lowering of cytochromes content with decrease in the enzyme activity, and K(m) and V(max). T(3) and T(R) regimens restored the cytochromes contents and the V(max) values to normal. In control, T(3) and T(R) groups the enzyme activity resolved in two kinetic components; in T(x) group three kinetic components were evident. The K(m) values for all components decreased significantly in the experimental groups with concomitant increase in catalytic efficiency, K(cat)/K(m). Significant alterations in the contents of total phospholipid and of cholesterol were noted while the changes in the phospholipids composition were only of restricted nature. Regression analysis revealed that total phospholipid, cholesterol and phosphatidylcholine, phosphatidylethanolamine play significant role in fine tuning the enzyme activity. PMID:23105769

  14. Stoichiometry of H+ ejection during respiration-dependent accumulation of Ca2+ by rat liver mitochondria.

    PubMed

    Brand, M D; Chen, C H; Lehninger, A L

    1976-02-25

    We have investigated the energy-dependent uptake of Ca2+ by rat liver mitochondria with succinate as respiratory substrate with rotenone added to block NAD-linked electron transport. In the presence of 3-hydroxybutyric or other permeant monocarboxylic acids Ca2+ was taken up to extents approaching those seen in the presence of phosphate. The quantitative relationship between cation and anion uptake was determined from the slope of a plot of 3-hydroxybutyrate uptake against Ca2+ uptake, a method which allowed determination of the stoichiometry without requiring ambiguous corrections for early nonenergized or nonstoichiometric binding events. This procedure showed that 2 molecules of 3-hydroxtbutyrate were accumulated with each Ca2+ ion. Under these conditions close to 2 Ca2+ ions and 4 molecules of 3-hydroxybutyrate were accumulated per pair of electrons per energy-conserving site of the respiratory chain. Since 3-hydroxybutyrate must be protonated to pass the membrane as the undissociated free acid, it is concluded that 4 protons were ejected (and subsequently reabsorbed) per pair of electrons per energy-conserving site, in contrast to the value 2.0 postulated by the chemiosmotic hypothesis. PMID:2609

  15. Long-chain fatty acids act as protonophoric uncouplers of oxidative phosphorylation in rat liver mitochondria.

    PubMed

    Schönfeld, P; Schild, L; Kunz, W

    1989-12-01

    The effect of long-chain fatty acids (LCFA) on respiration and transmembrane potential (delta psi) in the resting state, and the rate of delta psi dissipation [d delta psi/dt)i) was investigated with oligomycin-inhibited rat liver mitochondria using succinate (plus rotenone) as substrate. The results obtained were compared with those of classical protonophores such as 2,4-dinitrophenol (DNP) and 4,5,6,7-tetrachloro-2-trifluoromethylbenzimidazole (TTFB). The effects of oleate or palmitate and that of DNP or TTFB on respiration and delta psi can be described by a common force-flow relationship. These facts all in all are not compatible with a decoupler-type uncoupling mechanism of LCFA; still, they indicate that the latter are protonophores. Moreover, the oleate-induced increase in the rate of delta psi dissipation closely correlates with that in respiration, suggesting that the uncoupling activity and the protonophoric activity of LCFA are interrelated. Carboxyatractyloside (CAT) exerted only a small inhibitory effect on oleate-induced respiration and delta psi dissipation, indicating that the adenine nucleotide translocase contributes to the uncoupling effect of LCFA to a minor extent only. Proton transport through the lipid region of the membrane as mediated by permeation of the protonated and deprotonated forms of LCFA is interpreted as the main process of the uncoupling of LCFA. PMID:2556180

  16. Carbenoxolone induces oxidative stress in liver mitochondria, which is responsible for transition pore opening.

    PubMed

    Salvi, Mauro; Fiore, Cristina; Battaglia, Valentina; Palermo, Mario; Armanini, Decio; Toninello, Antonio

    2005-05-01

    Carbenoxolone (Cbx), a derivative of glycyrrhetinic acid, which has been found to affect mineralocorticoid and glucocorticoid receptors, induces swelling and membrane potential collapse when added to Ca(2+)-loaded liver mitochondria at 10 microM concentrations. These effects are strictly correlated with hydrogen peroxide generation, increase in oxygen uptake, and sulfhydryl and pyridine nucleotide oxidation. Cyclosporin A, bongkrekic acid, and N-ethylmaleimide completely abolish all the above-described effects, suggesting that Cbx can be considered an inducer of mitochondrial permeability transition by means of oxidative stress. Cbx can also trigger the apoptotic pathway because the above events are also correlated with the loss of cytochrome c. These effects are probably related to the conjugated carbonyl oxygen in C-11, which produces reactive oxygen species by interacting with the mitochondrial respiratory chain, mainly at the level of complex I but, most likely, also with complex III. The oxidative stress induced by Cbx, which is responsible for pore opening, excludes that this is related to a genomic effect of the compound. PMID:15677764

  17. Purification and characterization of a benzene hydroxylase: A cytochrome P-450 from rat liver mitochondria

    SciTech Connect

    Karaszkiewicz, J.W.

    1989-01-01

    This laboratory previously demonstrated that incubation of ({sup 14}C)benzene with isolated mitochondria resulted in the formation of mtDNA adducts. Since benzene is incapable of spontaneously covalently binding to nuclei acids, it was hypothesized that enzyme(s) present in the organelle metabolized benzene to reactive derivatives. We have purified, to electrophoretic homogeneity, a 52 kDa cytochrome P-450 from liver mitoplasts which metabolizes benzene to phenol. The enzyme has a K{sub M} for benzene of 0.012 mM, and a V{sub MAX} of 22.6 nmol phenol/nmol P-450/10 min, and requires NADPH, adrenodoxin, and adrenodoxin reductase for activity. Activity also can be reconstituted with microsomal cytochrome P-450 reductase. Benzene hydroxylase activity could be inhibited by carbon monoxide and SKF-525A, and by specific inhibitors of microsomal benzene metabolism. The purified enzyme oxidized phenol, forming catechol; aminopyrine N-demethylase activity was also demonstrated. These data confirm that a cytochrome P-450 of mitochondrial origin is involved in benzene metabolism, and indicate a role for the mitochondrion in xenobiotic activation.

  18. Liposomes from mammalian liver mitochondria are more polyunsaturated and leakier to protons than those from reptiles.

    PubMed

    Brand, M D; Couture, P; Hulbert, A J

    1994-06-01

    Liposomes were prepared from phospholipids extracted from liver mitochondria of the rat (Rattus norvegicus) and an agamid lizard, the bearded dragon (Amphibolurus vitticeps) and liposome proton conductance was measured at an imposed membrane potential of 160 mV as well as the fatty acid composition of the liposomes. Despite presumed changes in fatty acid composition during liposome preparation, the mammalian liposomes had a significantly lower content of the monounsaturated oleic acid and a significantly greater content of the omega-3 polyunsaturated docosahexaenoic acid. There were significant direct correlations between the liposome arachidonic and docosahexanoic acid content and bilayer proton flux and a significant inverse correlation between liposome oleic acid content and bilayer proton flux. "Apparent valinomycin-catalysed proton flux" was significantly directly correlated with liposome docosahexaenoic acid content and inversely correlated with oleic acid content. It is suggested that the high content of long-chain polyunsaturates in the mammalian mitochondrial membrane is responsible for an increased proton leak across the mitochondrial inner membrane and thus partly responsible for the high metabolic rate in endothermic mammals compared to their ectothermic reptilian predecessors. PMID:8055185

  19. Oxidation of cis-5-unsaturated fatty acids in intact rat liver mitochondria: the operation of reduction pathways.

    PubMed Central

    Tserng, K Y; Jin, S J

    1995-01-01

    The metabolism of cis-5 unsaturated fatty acids was studied in intact rat liver mitochondria to assess the operation of a reduction pathway. By using direct quantification of metabolites with a capillary-column gas chromatography, 3-hydroxydodecanoate was identified among other metabolites when cis-5-dodecenoate was metabolized in intact rat liver mitochondria. The formation of 3-hydroxydodecanoate supports the existence of a reduction pathway in the metabolism of cis-5-unsaturated fatty acids. This metabolite cannot be produced from the conventional isomerase-mediated pathway. However, the data also indicated the possible operation of the conventional isomerase-mediated pathway in intact rat liver mitochondria. The reduction pathway appears to account for at least 61% of the pathway for cis-5-dodecenoate. This reduction pathway was likely to proceed from the dehydrogenation to trans-2,cis-5-dodecadienoyl-CoA, which was isomerized to delta 3, delta 5-dodecadienoyl-CoA, then to trans-2,trans-4-dodecadienoate. The reduction was mediated by 2,4-dienoyl-CoA reductase by the conversion of trans-2,trans-4-dodecadienoyl-CoA into trans-3-dodecenoyl-CoA. However, direct reduction of the cis-5 double bond was also shown to be operating, although to a lesser extent. PMID:7755586

  20. Uncoupling effect of anacardic acids from cashew nut shell oil on oxidative phosphorylation of rat liver mitochondria.

    PubMed

    Toyomizu, M; Okamoto, K; Ishibashi, T; Chen, Z; Nakatsu, T

    2000-01-01

    Anacardic acids are one of natural products found in not only the cashew nut shell oil but also the nut and fruit juice. The present study was conducted to investigate the uncoupling effect of anacardic acids on oxidative phosphorylation of rat liver mitochondria using succinate (plus rotenone) as a substrate. Four anacardic acids with C15:0, C15:1, C15:2 or C15:3 as an alkyl side chain exhibited uncoupling effects similar to the classical uncoupler, 2,4-dinitrophenol on ADP/O ratio, state 4 and respiratory control ratio (RCR). Anacardic acid with C15:1 side chain was most effective for uncoupling of these compounds. Salicylic acid, which has no alkyl side chain, exhibited a very weak uncoupling effect on oxidative phosphorylation. When the carboxyl group in anacardic acids was lost converting them to the corresponding cardanols, uncoupling activity dramatically decreased regardless of the number of double bonds in the long alkyl chain. These results suggest that the C15 alkyl side chain as well as the carboxyl group may play an important role in assisting the uncoupling activity of anacardic acids in liver mitochondria of animals. This study provides the first evidence of an uncoupling effect of anacardic acids on liver mitochondria PMID:10665998

  1. Fructose-Drinking Water Induced Nonalcoholic Fatty Liver Disease and Ultrastructural Alteration of Hepatocyte Mitochondria in Male Wistar Rat

    PubMed Central

    Mamikutty, Norshalizah; Thent, Zar Chi; Haji Suhaimi, Farihah

    2015-01-01

    Background. Nonalcoholic fatty liver disease (NAFLD) is one of the complications of the metabolic syndrome. It encompasses a wide range of disease spectrum from simple steatosis to liver cirrhosis. Structural alteration of hepatic mitochondria might be involved in the pathogenesis of NAFLD. Aims. In the present study, we used a newly established model of fructose-induced metabolic syndrome in male Wistar rats in order to investigate the ultrastructural changes in hepatic mitochondria that occur with fructose consumption and their association with NAFLD pathogenesis. Methods. The concentration of fructose-drinking water (FDW) used in this study was 20%. Six male Wistar rats were supplemented with FDW 20% for eight weeks. Body composition and metabolic parameters were measured before and after 8 weeks of FDW 20%. Histomorphology of the liver was evaluated and ultrastructural changes of mitochondria were assessed with transmission electron micrograph. Results. After 8 weeks of fructose consumption, the animals developed several features of the metabolic syndrome. Moreover, fructose consumption led to the development of macrovesicular hepatic steatosis and mitochondrial ultrastructural changes, such as increase in mitochondrial size, disruption of the cristae, and reduction of matrix density. Conclusion. We conclude that in male Wistar rat 8-week consumption of FDW 20% leads to NAFLD likely via mitochondrial structural alteration. PMID:26273656

  2. Loss of brain function - liver disease

    MedlinePlus

    ... of chronic liver damage. Common causes of chronic liver disease in the United States are: Chronic hepatitis B ... hepatitis Bile duct disorders Some medicines Nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) Once you have ...

  3. Aluminium toxicity in the rat liver and brain

    NASA Astrophysics Data System (ADS)

    Yumoto, S.; Ohashi, H.; Nagai, H.; Kakimi, S.; Ishikawa, A.; Kobayashi, K.; Ogawa, Y.; Ishii, K.

    1993-04-01

    To investigate the etiology of Alzheimer's disease, we examined the brain and liver tissue uptake of aluminium 5-75 days after aluminium injection into healthy rats. Ten days after the last injection, Al was detected in the brain and the brain cell nuclei by particle-induced X-ray emission (PIXE) analysis. Al was also demonstrated in the liver and the liver cell nuclei by PIXE analysis and electron energy loss spectrometry (EELS). The morphological changes of the rat brain examined 75 days after the injection were similar to those which have been reportedly observed in the brain of patients with Alzheimer's disease. These results support the theory that Alzheimer's disease is caused by irreversible accumulation of aluminium in the brain, as well as in the nuclei of brain cells.

  4. Brain death and marginal grafts in liver transplantation

    PubMed Central

    Jiménez-Castro, M B; Gracia-Sancho, J; Peralta, C

    2015-01-01

    It is well known that most organs for transplantation are currently procured from brain-dead donors; however, the presence of brain death is an important risk factor in liver transplantation. In addition, one of the mechanisms to avoid the shortage of liver grafts for transplant is the use of marginal livers, which may show higher risk of primary non-function or initial poor function. To our knowledge, very few reviews have focused in the field of liver transplantation using brain-dead donors; moreover, reviews that focused on both brain death and marginal grafts in liver transplantation, both being key risk factors in clinical practice, have not been published elsewhere. The present review aims to describe the recent findings and the state-of-the-art knowledge regarding the pathophysiological changes occurring during brain death, their effects on marginal liver grafts and summarize the more controversial topics of this pathology. We also review the therapeutic strategies designed to date to reduce the detrimental effects of brain death in both marginal and optimal livers, attempting to explain why such strategies have not solved the clinical problem of liver transplantation. PMID:26043077

  5. Clusianone, a naturally occurring nemorosone regioisomer, uncouples rat liver mitochondria and induces HepG2 cell death.

    PubMed

    Reis, Felippe H Z; Pardo-Andreu, Gilberto L; Nuñez-Figueredo, Yanier; Cuesta-Rubio, Osmany; Marín-Prida, Javier; Uyemura, Sérgio A; Curti, Carlos; Alberici, Luciane C

    2014-04-01

    Clusianone is a member of the polycyclic polyprenylated acylphloroglucinol family of natural products; its cytotoxic mechanism is unknown. Clusianone is a structural isomer of nemorosone, which is a mitochondrial uncoupler and a well-known cytotoxic anti-cancer agent; thus, we addressed clusianone action at the mitochondria and its potential cytotoxic effects on cancer cells. In the HepG2 hepatocarcinoma cell line, clusianone induced mitochondrial membrane potential dissipation, ATP depletion and phosphatidyl serine externalization; this later event is indicative of apoptosis induction. In isolated mitochondria from rat liver, clusianone promoted protonophoric mitochondrial uncoupling. This was evidenced by the dissipation of mitochondrial membrane potential, an increase in resting respiration, an inhibition of Ca(2+) influx, stimulation of Ca(2+) efflux in Ca(2+)-loaded mitochondria, a decrease in ATP and NAD(P)H levels, generation of ROS, and swelling of valinomycin-treated organelles in hyposmotic potassium acetate media. The cytotoxic and uncoupling actions of clusianone were appreciably less than those of nemorosone, likely due to the presence of an intra-molecular hydrogen bond with the juxtaposed carbonyl group at the C15 position. Therefore, clusianone is capable of pharmacologically increasing the leakage of protons from the mitochondria and with favorable cytotoxicity in relation to nemorosone. PMID:24491676

  6. Role of Mitochondria in HIV Infection and Associated Metabolic Disorders: Focus on Nonalcoholic Fatty Liver Disease and Lipodystrophy Syndrome

    PubMed Central

    Pérez-Matute, P.; Pérez-Martínez, L.; Blanco, J. R.; Oteo, J. A.

    2013-01-01

    Highly active antiretroviral therapy (HAART) has considerably improved the prognosis of HIV-infected patients. However, prolonged use of HAART has been related to long-term adverse events that can compromise patient health such as HIV-associated lipodystrophy syndrome (HALS) and nonalcoholic fatty liver disease (NAFLD). There is consistent evidence for a central role of mitochondrial dysfunction in these pathologies. Nucleotide reverse transcriptase inhibitors (NRTIs) have been described to be mainly responsible for mitochondrial dysfunction in adipose tissue and liver although nonnucleoside transcriptase inhibitors (NNRTIs) or protease inhibitors (PIs) have also showed mitochondrial toxicity, which is a major concern for the selection and the long-term adherence to a particular therapy. Several mechanisms explain these deleterious effects of HAART on mitochondria, and evidence points to other mechanisms beyond the “Pol-γ hypothesis.” HIV infection has also direct effects on mitochondria. In addition to the negative effects described for HIV itself and/or HAART on mitochondria, HIV-infected patients are more prone to develop a premature aging and, therefore, to present an increased oxidative state that could lead to the development of these metabolic disturbances observed in HIV-infected patients. PMID:23970949

  7. Increased Susceptibility of Gracilinanus microtarsus Liver Mitochondria to Ca2+-Induced Permeability Transition Is Associated with a More Oxidized State of NAD(P)

    PubMed Central

    Ronchi, Juliana A.; Henning, Barbara; Ravagnani, Felipe G.; Figueira, Tiago R.; Castilho, Roger F.; dos Reis, Sergio F.; Vercesi, Anibal E.

    2015-01-01

    In addition to be the cell's powerhouse, mitochondria also contain a cell death machinery that includes highly regulated processes such as the membrane permeability transition pore (PTP) and reactive oxygen species (ROS) production. In this context, the results presented here provide evidence that liver mitochondria isolated from Gracilinanus microtarsus, a small and short life span (one year) marsupial, when compared to mice, are much more susceptible to PTP opening in association with a poor NADPH dependent antioxidant capacity. Liver mitochondria isolated from the marsupial are well coupled and take up Ca2+ but exhibited a much lower Ca2+ retention capacity than mouse mitochondria. Although the known PTP inhibitors cyclosporin A, ADP, and ATP significantly increased the marsupial mitochondria capacity to retain Ca2+, their effects were much larger in mice than in marsupial mitochondria. Both fluorescence and HPLC analysis of mitochondrial nicotinamide nucleotides showed that both content and state of reduction (mainly of NADPH) were lower in the marsupial mitochondria than in mice mitochondria despite the similarity in the activity of the glutathione peroxidase/reductase system. Overall, these data suggest that PTP opening is an important event in processes of Ca2+ signalling to cell death mediated by mitochondrial redox imbalance in G. microtarsus. PMID:26583063

  8. Contemporaneous isolation of deoxyribonucleic acid-dependent ribonucleic acid polymerase and poly(A) polymerase from rat liver mitochondria.

    PubMed Central

    Gallerani, R; di Istituto; Istituto di, Ch; Saccone, C

    1976-01-01

    1. Poly(A) polymerase and DNA-dependent RNA polymerase from rat liver mitochondria can be completely separated by using two different chromatographic procedures. 2. Poly(A) polymerase can only incorporate ATP into acid-insoluble material and strongly depends on the addition of an endogenous factor (probably containing a mixture of oligoribonucleotides), but it is not stimulated by DNA. 3. RNA polymerase is fully DNA-dependent and rifampicin-sensitive, but was not stimulated by the endogenous factor mentioned above. 4. The chromatographic behaviour of the two enzymes, together with the properties described, suggest that they represent two different protein molecules. PMID:962867

  9. Synergistic and antagonistic effects on fatty acid composition in the liver mitochondria of rats by thyroidectomy and streptozotocin-administration.

    PubMed

    Nishida, M; Sasaki, T; Terada, H; Kawada, J

    1991-12-01

    The content of individual fatty acid component in mitochondria of livers from thyroidectomized (Tx) and streptozotocin (STZ)-induced diabetic rats was measured to investigate how different hormones are interrelated to control the amount of a particular fatty acid in mitochondria. The results showed (1) diabetes, in general, affected fatty acid contents more severely than hypothyroidism, regardless of the direction of the changes; (2) Hypothyroidism and diabetes affected antagonistically the contents of C16 species and C18:1, which belong to a de novo synthesis (oleate series). However, the two pathological conditions affected synergistically those of higher unsaturated species, eg. C18:2, C20:3 and C20:4, which belong to a dietary-dependent synthesis (linoleate series). These results strongly indicated that each desaturation site and elongation site is affected in a preferential order by either thyroid hormone or insulin, and that hypothyroidism and diabetes have their effects differently on the process of de novo synthesis and the pathways initiated from an essential fatty acid in mitochondria. PMID:1837932

  10. Alzheimer's disease and type 2 diabetes-related alterations in brain mitochondria, autophagy and synaptic markers.

    PubMed

    Carvalho, Cristina; Santos, Maria S; Oliveira, Catarina R; Moreira, Paula I

    2015-08-01

    We aimed to investigate mitochondrial function, biogenesis and autophagy in the brain of type 2 diabetes (T2D) and Alzheimer's disease (AD) mice. Isolated brain mitochondria and homogenates from cerebral cortex and hippocampus of wild-type (WT), triple transgenic AD (3xTg-AD) and T2D mice were used to evaluate mitochondrial functional parameters and protein levels of mitochondrial biogenesis, autophagy and synaptic integrity markers, respectively. A significant decrease in mitochondrial respiration, membrane potential and energy levels was observed in T2D and 3xTg-AD mice. Also, a significant decrease in the levels of autophagy-related protein 7 (ATG7) and glycosylated lysosomal membrane protein 1 (LAMP1) was observed in cerebral cortex and hippocampus of T2D and 3xTg-AD mice. Moreover, both brain regions of 3xTg-AD mice present lower levels of nuclear respiratory factor (NRF) 1 while the levels of NRF2 are lower in both brain regions of T2D and 3xTg-AD mice. A decrease in mitochondrial encoded, nicotinamide adenine dinucleotide dehydrogenase subunit 1 (ND1) was also observed in T2D and 3xTg-AD mice although only statistically significant in T2D cortex. Furthermore, a decrease in the levels of postsynaptic density protein 95 (PSD95) in the cerebral cortex of 3xTg-AD mice and in hippocampus of T2D and 3xTg-AD mice and a decrease in the levels of synaptosomal-associated protein 25 (SNAP 25) in the hippocampus of T2D and 3xTg-AD mice were observed suggesting synaptic integrity loss. These results support the idea that alterations in mitochondrial function, biogenesis and autophagy cause synaptic damage in AD and T2D. PMID:25960150

  11. Calcium ions regulate K⁺ uptake into brain mitochondria: the evidence for a novel potassium channel.

    PubMed

    Skalska, Jolanta; Bednarczyk, Piotr; Piwońska, Marta; Kulawiak, Bogusz; Wilczynski, Grzegorz; Dołowy, Krzysztof; Kudin, Alexei P; Kunz, Wolfram S; Szewczyk, Adam

    2009-03-01

    The mitochondrial response to changes of cytosolic calcium concentration has a strong impact on neuronal cell metabolism and viability. We observed that Ca(2+) additions to isolated rat brain mitochondria induced in potassium ion containing media a mitochondrial membrane potential depolarization and an accompanying increase of mitochondrial respiration. These Ca(2+) effects can be blocked by iberiotoxin and charybdotoxin, well known inhibitors of large conductance potassium channel (BK(Ca) channel). Furthermore, NS1619 - a BK(Ca) channel opener - induced potassium ion-specific effects on brain mitochondria similar to those induced by Ca(2+). These findings suggest the presence of a calcium-activated, large conductance potassium channel (sensitive to charybdotoxin and NS1619), which was confirmed by reconstitution of the mitochondrial inner membrane into planar lipid bilayers. The conductance of the reconstituted channel was 265 pS under gradient (50/450 mM KCl) conditions. Its reversal potential was equal to 50 mV, which proved that the examined channel was cation-selective. We also observed immunoreactivity of anti-beta(4) subunit (of the BK(Ca) channel) antibodies with ~26 kDa proteins of rat brain mitochondria. Immunohistochemical analysis confirmed the predominant occurrence of beta(4) subunit in neuronal mitochondria. We hypothesize that the mitochondrial BK(Ca) channel represents a calcium sensor, which can contribute to neuronal signal transduction and survival. PMID:19399240

  12. Hepatic encephalopathy: effects of liver failure on brain function.

    PubMed

    Felipo, Vicente

    2013-12-01

    Liver failure affects brain function, leading to neurological and psychiatric alterations; such alterations are referred to as hepatic encephalopathy (HE). Early diagnosis of minimal HE reveals an unexpectedly high incidence of mild cognitive impairment and psychomotor slowing in patients with liver cirrhosis - conditions that have serious health, social and economic consequences. The mechanisms responsible for the neurological alterations in HE are beginning to emerge. New therapeutic strategies acting on specific targets in the brain (phosphodiesterase 5, type A GABA receptors, cyclooxygenase and mitogen-activated protein kinase p38) have been shown to restore cognitive and motor function in animal models of chronic HE, and NMDA receptor antagonists have been shown to increase survival in acute liver failure. This article reviews the latest studies aimed at understanding how liver failure affects brain function and potential ways to ameliorate these effects. PMID:24149188

  13. Diamide accelerates opening of the Tl(+)-induced permeability transition pore in Ca(2+)-loaded rat liver mitochondria.

    PubMed

    Korotkov, Sergey M; Konovalova, Svetlana A; Brailovskaya, Irina V

    Opening of the mitochondrial permeability transition pore (MPTP) in the inner membrane is due to matrix Ca(2+) overload and matrix glutathione loss. Fixing the 'm' conformation of the adenine nucleotide translocase (ANT) by ADP or N-ethylmaleimide (NEM) inhibits opening of the MPTP. Oxidants (diamide or tert-butylhydroperoxide (tBHP)) fix the ANT in 'c' conformation, and the ability of ADP to inhibit the MPTP is thus attenuated. Earlier we found (Korotkov and Saris, 2011) that calcium load of rat liver mitochondria resulted in Tl(+)-induced MPTP opening, which was accompanied by a decrease in state 3, state 4, and 2,4-dinitrophenol-uncoupled respiration, as well as increased swelling and membrane potential dissipation. These effects, which were increased by diamide and tBHP, were visibly reduced in the presence of the MPTP inhibitors (ADP, NEM, and cyclosporine A). Our data suggest that conformational changes of the ANT and matrix glutathione loss may be directly involved in opening the Tl(+)-induced MPTP in the inner membrane of Ca(2+)-loaded rat liver mitochondria. PMID:26518646

  14. Mechanism of induction of oxidative stress in liver mitochondria by low concentrations of tert-butyl hydroperoxide.

    PubMed

    Fedotcheva, N I; Mokhova, E N

    2013-01-01

    The mechanism of the effect of tert-butyl hydroperoxide (tBHP) on the kinetics of decrease in liver mitochondrial ΔΨ (transmembrane electric potential) in response to successive additions of tBHP in low concentrations has been studied. FeSO(4) was found to increase significantly the damaging effect of tBHP; this effect was shown to increase in the presence of low concentrations of Ca2+ starting from 2 µM CaCl(2). Cyclosporin A prevents these effects. The data show that the damaging effect of low concentrations of tBHP in the course of pyruvate oxidation in isolated liver mitochondria is caused by the opening of the nonspecific Ca2+-dependent cyclosporin A-sensitive pore in the inner mitochondrial membrane. Application of a method of studying oxidative stress regulators, developed in this work, is illustrated by an example of the prooxidant action of ascorbate. This method is proposed for studying mitochondria in hemochromatosis, a pathology caused by excessive accumulation of iron. PMID:23379562

  15. Determination of boron distribution in rat's brain, kidney and liver.

    PubMed

    Pazirandeh, Ali; Jameie, Behnam; Zargar, Maysam

    2009-07-01

    To determine relative boron distribution in rat's brain, liver and kidney, a mixture of boric acid and borax, was used. After transcardial injection of the solution, the animals were sacrificed and the brain, kidney and liver were removed. The coronal sections of certain areas of the brain were prepared by freezing microtome. The slices were sandwiched within two pieces of CR-39. The samples were bombarded in a thermal neutron field of the TRR pneumatic facility. The alpha tracks are registered on CR-39 after being etched in NaOH. The boron distribution was determined by counting these alpha tracks CR-39 plastics. The distribution showed non-uniformity in brain, liver and kidney. PMID:19375929

  16. 1,3-dinitrobenzene induces age- and region-specific oxidation to mitochondria-related proteins in brain.

    PubMed

    Kubik, Laura L; Landis, Rory W; Remmer, Henriette; Bergin, Ingrid L; Philbert, Martin A

    2015-05-01

    Regions of the brain with high energy requirements are especially sensitive to perturbations in mitochondrial function. Hence, neurotoxicant exposures that target mitochondria in regions of high energy demand have the potential to accelerate mitochondrial damage inherently occurring during the aging process. 1,3-Dinitrobenzene (DNB) is a model neurotoxicant that selectively targets mitochondria in brainstem nuclei innervated by the eighth cranial nerve. This study investigates the role of age in the regional susceptibility of brain mitochondria-related proteins (MRPs) to oxidation following exposure to DNB. Male F344 rats (1 month old [young], 3 months old [adult], 18 months old [aged]) were exposed to 10 mg/kg DNB prior to mitochondrial isolation and histopathology experiments. Using a high-throughput proteomic approach, 3 important region- and age-related increases in DNB-induced MRP oxidation were determined: (1) brainstem mitochondria are ×3 more sensitive to DNB-induced oxidation than cortical mitochondria; (2) oxidation of brainstem MRPs is significantly higher than in cortical counterparts; and (3) MRPs from the brainstems of older rats are significantly more oxidized than those from young or adult rats. Furthermore, lower levels of DNB cause signs of intoxication (ataxia, chromodacryorrhea) and vacuolation of the susceptible neuropil in aged animals, while neither is observed in DNB-exposed young rats. Additionally, methemoglobin levels increase significantly in DNB-exposed adult and aged animals, but not young DNB-exposed animals. This suggests that oxidation of key MRPs observed in brainstem of aged animals is necessary for DNB-induced signs of intoxication and lesion formation. These results provide compelling evidence that environmental chemicals such as DNB may aid in the acceleration of injury to specific brain regions by inducing oxidation of sensitive mitochondrial proteins. PMID:25716674

  17. 1,3-Dinitrobenzene Induces Age- and Region-Specific Oxidation to Mitochondria-Related Proteins in Brain

    PubMed Central

    Kubik, Laura L.; Landis, Rory W.; Remmer, Henriette; Bergin, Ingrid L.; Philbert, Martin A.

    2015-01-01

    Regions of the brain with high energy requirements are especially sensitive to perturbations in mitochondrial function. Hence, neurotoxicant exposures that target mitochondria in regions of high energy demand have the potential to accelerate mitochondrial damage inherently occurring during the aging process. 1,3-Dinitrobenzene (DNB) is a model neurotoxicant that selectively targets mitochondria in brainstem nuclei innervated by the eighth cranial nerve. This study investigates the role of age in the regional susceptibility of brain mitochondria-related proteins (MRPs) to oxidation following exposure to DNB. Male F344 rats (1 month old [young], 3 months old [adult], 18 months old [aged]) were exposed to 10 mg/kg DNB prior to mitochondrial isolation and histopathology experiments. Using a high-throughput proteomic approach, 3 important region- and age-related increases in DNB-induced MRP oxidation were determined: (1) brainstem mitochondria are ×3 more sensitive to DNB-induced oxidation than cortical mitochondria; (2) oxidation of brainstem MRPs is significantly higher than in cortical counterparts; and (3) MRPs from the brainstems of older rats are significantly more oxidized than those from young or adult rats. Furthermore, lower levels of DNB cause signs of intoxication (ataxia, chromodacryorrhea) and vacuolation of the susceptible neuropil in aged animals, while neither is observed in DNB-exposed young rats. Additionally, methemoglobin levels increase significantly in DNB-exposed adult and aged animals, but not young DNB-exposed animals. This suggests that oxidation of key MRPs observed in brainstem of aged animals is necessary for DNB-induced signs of intoxication and lesion formation. These results provide compelling evidence that environmental chemicals such as DNB may aid in the acceleration of injury to specific brain regions by inducing oxidation of sensitive mitochondrial proteins. PMID:25716674

  18. Loss of brain function - liver disease

    MedlinePlus

    ... may be made by the body, such as ammonia. Or they may be substances that you take ... MRI EEG Liver function tests Prothrombin time Serum ammonia level Sodium level in the blood Potassium level ...

  19. Role of mitochondria in apoptotic and necroptotic cell death in the developing brain

    PubMed Central

    Thornton, Claire; Hagberg, Henrik

    2015-01-01

    Hypoxic–ischemic encephalopathy induces secondary brain injury characterized by delayed energy failure. Currently, therapeutic hypothermia is the sole treatment available after severe intrapartum asphyxia in babies and acts to attenuate secondary loss of high energy phosphates improving both short- and long-term outcome. In order to develop the next generation of neuroprotective therapies, we urgently need to understand the underlying molecular mechanisms leading to cell death. Hypoxia–ischemia creates a toxic intracellular environment including accumulation of reactive oxygen/nitrosative species and intracellular calcium after the insult, inducing mitochondrial impairment. More specifically mitochondrial respiration is suppressed and calcium signaling is dysregulated. At a certain threshold, Bax-dependent mitochondrial permeabilization will occur leading to activation of caspase-dependent and apoptosis-inducing factor-dependent apoptotic cell death. In addition, hypoxia–ischemia induces inflammation, which leads to the release of TNF-α, TRAIL, TWEAK, FasL and Toll-like receptor agonists that will activate death receptors on neurons and oligodendroglia. Death receptors trigger apoptotic death via caspase-8 and necroptotic cell death through formation of the necrosome (composed of RIP1, RIP3 and MLKL), both of which converge at the mitochondria. PMID:25661091

  20. Purification and properties of L-3-glycerophosphate dehydrogenase from pig brain mitochondria.

    PubMed Central

    Cottingham, I R; Ragan, C I

    1980-01-01

    L-3-Glycerophosphate dehydrogenase (EC 1.1.99.5) was purified from pig brain mitochondria by extraction with deoxycholate, ion-exchange chromatography and (NH4)2SO4 fractionation in cholate, and preparative isoelectric focusing in Triton X-100. Sodium dodecyl sulphate/polyacrylamide gel electrophoresis shows that the purified enzyme consists of a single subunit of mol.wt. 75 000. The enzyme contains non-covalently bound FAD and low concentrations of iron and acid labile sulphide. No substrate reducible e.p.r. signals were detected. The conditions of purification, particularly the isoelectric focusing step, lead to considerable loss of FAD and possibly iron-sulphur centres. It is therefore not possible to decide with certainty whether the enzyme is a flavoprotein or a ferroflavoprotein. The enzyme catalyses the oxidation of L-3-glycerophosphate by a variety of electron acceptors, including ubiquinone analogues. A number if compounds known to inhibit ubiquinone oxidoreduction by other enzymes of the respiratory chain failed to inhibit L-3-glycerophosphate dehydrogenase, except at very high concentrations. Images Fig. 3. PMID:6796038

  1. Atherosclerotic lesions and mitochondria DNA deletions in brain microvessels: implication in the pathogenesis of Alzheimer's disease.

    PubMed

    Aliev, Gjumrakch; Gasimov, Eldar; Obrenovich, Mark E; Fischbach, Kathryn; Shenk, Justin C; Smith, Mark A; Perry, George

    2008-01-01

    The pathogenesis that is primarily responsible for Alzheimer's disease (AD) and cerebrovascular accidents (CVA) appears to involve chronic hypoperfusion. We studied the ultrastructural features of vascular lesions and mitochondria in brain vascular wall cells from human AD biopsy samples and two transgenic mouse models of AD, yeast artificial chromosome (YAC) and C57B6/SJL Tg (+), which overexpress human amyloid beta precursor protein (AbetaPP). In situ hybridization using probes for normal and 5 kb deleted human and mouse mitochondrial DNA (mtDNA) was performed along with immunocytochemistry using antibodies against the Abeta peptide processed from AbetaPP, 8-hydroxy-2'-guanosine (8OHG), and cytochrome c oxidase (COX). More amyloid deposition, oxidative stress markers as well as mitochondrial DNA deletions and structural abnormalities were present in the vascular walls of the human AD samples and the AbetaPP-YAC and C57B6/SJL Tg (+) transgenic mice compared to age-matched controls. Ultrastructural damage in perivascular cells highly correlated with endothelial lesions in all samples. Therefore, pharmacological interventions, directed at correcting the chronic hypoperfusion state, may change the natural course of the development of dementing neurodegeneration. PMID:18827923

  2. Asiatic acid uncouples respiration in isolated mouse liver mitochondria and induces HepG2 cells death.

    PubMed

    Lu, Yapeng; Liu, Siyuan; Wang, Ying; Wang, Dang; Gao, Jing; Zhu, Li

    2016-09-01

    Asiatic acid, one of the triterpenoid components isolated from Centella asiatica, has received increasing attention due to a wide variety of biological activities. To date, little is known about its mechanisms of action. Here we examined the cytotoxic effect of asiatic acid on HepG2 cells and elucidated some of the underlying mechanisms. Asiatic acid induced rapid cell death, as well as mitochondrial membrane potential (MMP) dissipation, ATP depletion and cytochrome c release from mitochondria to the cytosol in HepG2 cells. In mitochondria isolated from mouse liver, asiatic acid treatment significantly stimulated the succinate-supported state 4 respiration rate, dissipated the MMP, increased Ca(2+) release from Ca(2+)-loaded mitochondria, decreased ATP content and promoted cytochrome c release, indicating the uncoupling effect of asiatic acid. Hydrogen peroxide (H2O2) produced by succinate-supported mitochondrial respiration was also significantly inhibited by asiatic acid. In addition, asiatic acid inhibited Ca(2+)-induced mitochondrial swelling but did not induce mitochondrial swelling in hyposmotic potassium acetate medium which suggested that asiatic acid may not act as a protonophoric uncoupler. Inhibition of uncoupling proteins (UCPs) or blockade of adenine nucleotide transporter (ANT) attenuated the effect of asiatic acid on MMP dissipation, Ca(2+) release, mitochondrial respiration and HepG2 cell death. When combined inhibition of UCPs and ANT, asiatic acid-mediated uncoupling effect was noticeably alleviated. These results suggested that both UCPs and ANT partially contribute to the uncoupling properties of asiatic acid. In conclusion, asiatic acid is a novel mitochondrial uncoupler and this property is potentially involved in its toxicity on HepG2 cells. PMID:27288117

  3. Phosphate and calcium uptake by mitochondria and by perfused rat liver induced by the synergistic action of glucagon and vasopressin.

    PubMed Central

    Bygrave, F L; Lenton, L; Altin, J G; Setchell, B A; Karjalainen, A

    1990-01-01

    Co-administration of glucagon and vasopressin to rat liver perfused with buffer containing 1.3 mM-Ca2+ induces a 4-fold increase in Pi in the subsequently isolated mitochondria (from approx. 9 to approx. 40 nmol/mg of mitochondrial protein). This increase is not attributable to PPi hydrolysis, and is not observed if the perfusate Ca2+ is lowered from 1.3 mM to 50 microM. The increase in mitochondrial Pi closely parallels that of mitochondrial Ca2+; when the increase in Pi and Ca2+ accumulation is maximal, the molar ratio is close to that in Ca3(PO4)2. Measurement of changes in the perfusate Pi revealed that, whereas administration of glucagon or vasopressin alone brought about a rapid decline in perfusate Pi, the largest decrease (reflecting net retention of Pi by the liver) was observed when the hormone was co-administered in the presence of 1.3 mM-Ca2+. The synergistic action of glucagon plus vasopressin was nullified by lowering the perfusate Ca2+ to 50 microM. The data provide evidence that, whereas glucagon may be able to alter Pi fluxes directly in intact liver, any alterations induced by vasopressin are indirect and result only from its action of mobilizing Ca2+. PMID:2327989

  4. Direct measurement of the initial proton extrusion to oxygen uptake ratio accompanying succinate oxidation by rat liver mitochondria.

    PubMed

    Setty, O H; Shrager, R I; Bunow, B; Reynafarje, B; Lehninger, A L; Hendler, R W

    1986-09-01

    The problem of obtaining very early ratios for the H+/O stoichiometry accompanying succinate oxidation by rat liver mitochondria was attacked using new techniques for direct measurement rather than extrapolations based on data obtained after mixing and the recovery of the electrode from initial injection of O2. Respiration was quickly initiated in a thoroughly mixed O2-containing suspension of mitochondria under a CO atmosphere by photolysis of the CO-cytochrome c oxidase complex-. Fast responding O2 and pH electrodes were used to collect data every 10 ms. The response time for each electrode was experimentally measured in each experiment and suitable corrections for electrode relaxations were made. With uncorrected data obtained after 0.8 s, the extrapolation back to zero time on the basis of single-exponential curve fitting confirmed values close to 8.0 as previously reported (Costa et al., 1984). The data directly obtained, however, indicate an initial burst in H+/O ratio that peaked to values of approximately 20 to 30 prior to 50 ms and which was no longer evident after 0.3 s. Newer information and considerations that place all extrapolation methods in question are discussed. PMID:3019443

  5. Direct measurement of the initial proton extrusion to oxygen uptake ratio accompanying succinate oxidation by rat liver mitochondria.

    PubMed Central

    Setty, O H; Shrager, R I; Bunow, B; Reynafarje, B; Lehninger, A L; Hendler, R W

    1986-01-01

    The problem of obtaining very early ratios for the H+/O stoichiometry accompanying succinate oxidation by rat liver mitochondria was attacked using new techniques for direct measurement rather than extrapolations based on data obtained after mixing and the recovery of the electrode from initial injection of O2. Respiration was quickly initiated in a thoroughly mixed O2-containing suspension of mitochondria under a CO atmosphere by photolysis of the CO-cytochrome c oxidase complex-. Fast responding O2 and pH electrodes were used to collect data every 10 ms. The response time for each electrode was experimentally measured in each experiment and suitable corrections for electrode relaxations were made. With uncorrected data obtained after 0.8 s, the extrapolation back to zero time on the basis of single-exponential curve fitting confirmed values close to 8.0 as previously reported (Costa et al., 1984). The data directly obtained, however, indicate an initial burst in H+/O ratio that peaked to values of approximately 20 to 30 prior to 50 ms and which was no longer evident after 0.3 s. Newer information and considerations that place all extrapolation methods in question are discussed. PMID:3019443

  6. Identification of compounds from high-fat and extra virgin olive oil-supplemented diets in whole mouse liver extracts and isolated mitochondria using mass spectrometry.

    PubMed

    dos Santos, Gustavo Aparecido; Ferreira, Mônica Siqueira; de Oliveira, Diogo Noin; de Oliveira, Vanessa; Siqueira-Santos, Edilene S; Cintra, Dennys Esper Corrêa; Castilho, Roger Frigério; Velloso, Lício Augusto; Catharino, Rodrigo Ramos

    2015-07-01

    Nonalcoholic steatohepatitis (NASH) is a fatty liver disorder that could be improved with extra virgin olive oil (EVOO) supplementation in diet. We propose the monitoring, in whole mouse liver extracts and in isolated mitochondria, of the absorption of compounds from three different diets: standard (CT), high-fat (HFD) and high-fat supplemented with EVOO (HFSO). Male mice were submitted to one of the following three diets: CT or HFD for 16 weeks or HFD for 8 weeks followed by additional 8 weeks with HFSO. Following this period, liver was extracted for histological evaluation, mitochondria isolation and mass spectrometry analyses. Diets, liver extracts and Percoll-purified mitochondria were analyzed using ESI-MS and the lipidomics approach. Morphological, histological and spectrometric results indicated a decrease in NASH severity with EVOO supplementation in comparison with animals maintained with HFD. Spectrometric data also demonstrated that some compounds presented on the diets are absorbed by the mitochondria. EVOO was shown to be a potential therapeutic alternative in food for NASH. Our results are in accordance with the proposition that the major factor that influences different responses to diets is their composition - and not only calories - especially when it comes to studies on obesity. PMID:26349651

  7. A permeability transition in liver mitochondria and liposomes induced by α,ω-dioic acids and Ca(2+).

    PubMed

    Dubinin, Mikhail V; Samartsev, Victor N; Astashev, Maxim E; Kazakov, Alexey S; Belosludtsev, Konstantin N

    2014-11-01

    The article examines the molecular mechanism of the Ca(2+)-dependent cyclosporin A (CsA)-insensitive permeability transition in rat liver mitochondria induced by α,ω-dioic acids. The addition of α,ω-hexadecanedioic acid (HDA) to Ca(2+)-loaded liver mitochondria was shown to induce a high-amplitude swelling of the organelles, a drop of membrane potential and the release of Ca(2+) from the matrix, the effects being insensitive to CsA. The experiments with liposomes loaded with sulforhodamine B (SRB) revealed that, like palmitic acid (PA), HDA was able to cause permeabilization of liposomal membranes. However, the kinetics of HDA- and PA-induced release of SRB from liposomes was different, and HDA was less effective than PA in the induction of SRB release. Using the method of ultrasound interferometry, we also showed that the addition of Ca(2+) to HDA-containing liposomes did not change the phase state of liposomal membranes-in contrast to what was observed when Ca(2+) was added to PA-containing vesicles. It was suggested that HDA/Ca(2+)- and PA/Ca(2+)-induced permeability transition occurs by different mechanisms. Using the method of dynamic light scattering, we further revealed that the addition of Ca(2+) to HDA-containing liposomes induced their aggregation/fusion. Apparently, these processes result in a partial release of SRB due to the formation of fusion pores. The possibility that this mechanism underlies the HDA/Ca(2+)-induced permeability transition of the mitochondrial membrane is discussed. PMID:25217975

  8. Blood-brain barrier in acute liver failure

    PubMed Central

    Nguyen, Justin H.

    2011-01-01

    Brain edema remains a challenging obstacle in the management of acute liver failure (ALF). Cytotoxic mechanisms associated with brain edema have been well recognized, but evidence for vasogenic mechanisms in the pathogenesis of brain edema in ALF has been lacking. Recent reports have not only shown a role of matrix metalloproteinase-9 in the pathogenesis of brain edema in experimental ALF but have also found significant alterations in the tight junction elements including occludin and claudin-5, suggesting a vasogenic injury in the blood-brain barrier (BBB) integrity. This article reviews and explores the role of the paracellular tight junction proteins in the increased selective BBB permeability that leads to brain edema in ALF. PMID:22100566

  9. More about Interactions of Rhodamine 19 Butyl Ester with Rat Liver Mitochondria.

    PubMed

    Rogov, A G; Trendeleva, T A; Aliverdieva, D A; Zvyagilskaya, R A

    2016-04-01

    Oxidative stress is one of the major factors underlying mitochondrial dysfunctions. One of the most promising approaches for alleviating or preventing oxidative stress is the use of cationic uncouplers that accumulate in mitochondria in accordance to the level of the membrane potential, producing "mild" uncoupling. Based on this theoretical background, cationic rhodamine 19 butyl ester (C4R1) was synthesized and tested within the framework of the research project guided by V. P. Skulachev. The results of these tests were presented (Khailova et al. (2014) Biochim. Biophys. Acta, 1837, 1739-1747), but one publication could not accommodate all data on interactions of C4R1 with isolated mitochondria. In addition to previously presented data, we found that the effect of C4R1 on the rate of oxygen uptake is subject to temporal variations, which probably reflects variable rates of C4R1 entry into the mitochondria. Consequently, transient stimulation of respiration can be followed by inhibition. C4R1 was found not to shunt electron flow from complex I of the respiratory chain; it largely acted as an inhibitor of complex I in the respiratory chain and showed antioxidant activity. C4R1 taken at low, non-uncoupling concentrations enhanced the uncoupling activity of fatty acids (e.g. palmitate). Relatively low C4R1 concentrations stimulated opening of a nonspecific Ca2+/Pi-dependent pore. ATP synthesis and hydrolysis were substantially inhibited by C4R1 at low concentrations that had no appreciable effects on respiration in states 4 and 3 and only slightly decreased the membrane potential. Besides, conditions were revealed allowing correct evaluation of the membrane potential generated at the inner mitochondrial membrane with safranin O upon oxidation of both succinate and NAD-dependent substrates in the presence of C4R1. PMID:27293102

  10. Brain region-specific altered expression and association of mitochondria-related genes in autism

    PubMed Central

    2012-01-01

    Background Mitochondrial dysfunction (MtD) has been observed in approximately five percent of children with autism spectrum disorders (ASD). MtD could impair highly energy-dependent processes such as neurodevelopment, thereby contributing to autism. Most of the previous studies of MtD in autism have been restricted to the biomarkers of energy metabolism, while most of the genetic studies have been based on mutations in the mitochondrial DNA (mtDNA). Despite the mtDNA, most of the proteins essential for mitochondrial replication and function are encoded by the genomic DNA; so far, there have been very few studies of those genes. Therefore, we carried out a detailed study involving gene expression and genetic association studies of genes related to diverse mitochondrial functions. Methods For gene expression analysis, postmortem brain tissues (anterior cingulate gyrus (ACG), motor cortex (MC) and thalamus (THL)) from autism patients (n=8) and controls (n=10) were obtained from the Autism Tissue Program (Princeton, NJ, USA). Quantitative real-time PCR arrays were used to quantify the expression of 84 genes related to diverse functions of mitochondria, including biogenesis, transport, translocation and apoptosis. We used the delta delta Ct (∆∆Ct) method for quantification of gene expression. DNA samples from 841 Caucasian and 188 Japanese families were used in the association study of genes selected from the gene expression analysis. FBAT was used to examine genetic association with autism. Results Several genes showed brain region-specific expression alterations in autism patients compared to controls. Metaxin 2 (MTX2), neurofilament, light polypeptide (NEFL) and solute carrier family 25, member 27 (SLC25A27) showed consistently reduced expression in the ACG, MC and THL of autism patients. NEFL (P = 0.038; Z-score 2.066) and SLC25A27 (P = 0.046; Z-score 1.990) showed genetic association with autism in Caucasian and Japanese samples, respectively. The expression of

  11. Brain edema in acute liver failure. Insight from experimental studies.

    PubMed

    Andres, T; Blei, M D; Judy, R; Cho, M D

    1990-07-01

    Brain edema is a leading cause of death in fulminant hepatic failure (FHP). Animal studies are needed to gain further insight into its pathogenesis. The authors describe and analyze the results of brain studies in two animal models of FHF, the rabbit with galactosamine induced hepatitis and the anhepatic model of liver desvascularization. A gravimetric technique is used to determine water content in brain samples as small as 10 mg in weight. Results showed that water content is increased and correlates with the severity of encephalopathy in both experimental models of encephalopathy. The possible pathogenic role of ammonia and octanoic acid are discussed. PMID:19256151

  12. H sup + -ATP synthase from rat liver mitochondria. A simple, rapid purification method of the functional complex and its characterization

    SciTech Connect

    Yoshihara, Yutaka; Nagase, Hideki; Yamane, Takeshi; Oka, Hideki; Tani, Isamu; Higuti, Tomihiko )

    1991-07-16

    A novel, simple, and rapid preparative method for purification of rat liver H{sup +}-ATP synthase by anion-exchange HPLC was developed. The H{sup +}-ATP synthase purified had higher ATPase activity in the absence of added phospholipids than any preparation reported previously, and this activity was completely inhibited by oligomycin. When reconstituted into proteoliposomes, the H{sup +}-ATP synthase showed an ATP-dependent 8-anilinonaphthalene-1-sulfonate response and ATP-P{sub i} exchange activity, both of which were also completely inhibited by oligomycin and an uncoupler, indicating the intactness of the H{sup +}-ATP synthase. An immunochemical study and a labeling experiment with N,N{prime}-({sup 14}C)dicyclohexylcarbondiimide (({sup 14}C)DCCD) demonstrated the presence of chargerin II (a product of mitochondrial A6L DNA) and DCCD-binding protein (subunit c) in the complex. The subunits of the complex were separated into 11 main fractions by reverse-phase HPLC, and 3 of them and the {sigma} subunit in F{sub 1} were partially sequenced. A search for sequence homologies indicated that these components were subunit b, coupling factor 6, subunit {sigma}, and subunit e. This is the first report of the existence of subunit b, factor 6, and chargerin II in K{sup +}-ATP synthase purified from rat liver mitochondria.

  13. Oxidative Inactivation of Liver Mitochondria in High Fructose Diet-Induced Metabolic Syndrome in Rats: Effect of Glycyrrhizin Treatment.

    PubMed

    Sil, Rajarshi; Chakraborti, Abhay Sankar

    2016-09-01

    Metabolic syndrome is a serious health problem in the present world. Glycyrrhizin, a triterpenoid saponin of licorice (Glycyrrhiza glabra) root, has been reported to ameliorate the primary complications and hepatocellular damage in rats with the syndrome. In this study, we have explored metabolic syndrome-induced changes in liver mitochondrial function and effect of glycyrrhizin against the changes. Metabolic syndrome was induced in rats by high fructose (60%) diet for 6 weeks. The rats were then treated with glycyrrhizin (50 mg/kg body weight) by single intra-peritoneal injection. After 2 weeks of the treatment, the rats were sacrificed to collect liver tissue. Elevated mitochondrial ROS, lipid peroxidation and protein carbonyl, and decreased reduced glutathione content indicated oxidative stress in metabolic syndrome. Loss of mitochondrial inner membrane cardiolipin was observed. Mitochondrial complex I activity did not change but complex IV activity decreased significantly. Mitochondrial MTT reduction ability, membrane potential, phosphate utilisation and oxygen consumption decreased in metabolic syndrome. Reduced mitochondrial aconitase activity and increased aconitase carbonyl content suggested oxidative damage of the enzyme. Elevated Fe(2+) ion level in mitochondria might be associated with increased ROS generation in metabolic syndrome. Glycyrrhizin effectively attenuated mitochondrial oxidative stress and aconitase degradation, and improved electron transport chain activity. Copyright © 2016 John Wiley & Sons, Ltd. PMID:27255442

  14. Cinnamon intake alleviates the combined effects of dietary-induced insulin resistance and acute stress on brain mitochondria.

    PubMed

    Couturier, Karine; Hininger, Isabelle; Poulet, Laurent; Anderson, Richard A; Roussel, Anne-Marie; Canini, Frédéric; Batandier, Cécile

    2016-02-01

    Insulin resistance (IR), which is a leading cause of the metabolic syndrome, results in early brain function alterations which may alter brain mitochondrial functioning. Previously, we demonstrated that rats fed a control diet and submitted to an acute restraint stress exhibited a delayed mitochondrial permeability transition pore (mPTP) opening. In this study, we evaluated the combined effects of dietary and emotional stressors as found in western way of life. We studied, in rats submitted or not to an acute stress, the effects of diet-induced IR on brain mitochondria, using a high fat/high fructose diet (HF(2)), as an IR inducer, with addition or not of cinnamon as an insulin sensitizer. We measured Ca(2+) retention capacity, respiration, ROS production, enzymatic activities and cell signaling activation. Under stress, HF(2) diet dramatically decreased the amount of Ca(2+) required to open the mPTP (13%) suggesting an adverse effect on mitochondrial survival. Cinnamon added to the diet corrected this negative effect and resulted in a partial recovery (30%). The effects related to cinnamon addition to the diet could be due to its antioxidant properties or to the observed modulation of PI3K-AKT-GSK3β and MAPK-P38 pathways or to a combination of both. These data suggest a protective effect of cinnamon on brain mitochondria against the negative impact of an HF(2) diet. Cinnamon could be beneficial to counteract deleterious dietary effects in stressed conditions. PMID:26878796

  15. Isolation of mitochondria from cultured cells and liver tissue biopsies for molecular and biochemical analyses.

    PubMed

    Schmitt, Sabine; Eberhagen, Carola; Weber, Susanne; Aichler, Michaela; Zischka, Hans

    2015-01-01

    We recently reported a new method to isolate functionally intact mitochondria from cell culture and small tissue samples (Schmitt et al., Anal Biochem 443(1):66-74, 2013). This method comprises a semi-automated cell rupture, termed pump controlled cell rupture system (PCC), which can be precisely adjusted to the specific cellular source of isolation and which can be tightly controlled (Schmitt et al., Anal Biochem 443(1):66-74, 2013). Here we provide a detailed hands-on protocol of this PCC method which results in an efficient cell breakage but preserving the mitochondrial integrity. Upon subsequent purification steps, the obtained mitochondrial fraction meets the quality and purity required for molecular analyses, e.g. proteomic comparisons, as well as for biochemical analyses, e.g. determination of diverse enzymatic activities. PMID:25820716

  16. Rotenone exerts similar stimulatory effects on H2O2 production by isolated brain mitochondria from young-adult and old rats.

    PubMed

    Michelini, Luiz G B; Figueira, Tiago R; Siqueira-Santos, Edilene S; Castilho, Roger F

    2015-03-01

    Chronic and systemic treatment of rodents with rotenone, a classical inhibitor of mitochondrial respiratory complex I, results in neurochemical, behavioral, and neuropathological features of Parkinson's disease. The aim of the present study was to evaluate whether brain mitochondria from old rats (24 months old) would be more susceptible to rotenone-induced inhibition of oxygen consumption and increased generation of H2O2 than mitochondria from young-adult rats (3-4 months old). Isolated brain mitochondria were incubated in the presence of different rotenone concentrations (5, 10, and 100nM), and oxygen consumption and H2O2 production were measured during respiratory states 3 (ADP-stimulated respiration) and 4 (resting respiration). Respiratory state 3 and citrate synthase activity were significantly lower in mitochondria from old rats. Mitochondria from young-adult and old rats showed similar sensitivity to rotenone-induced inhibition of oxygen consumption. Similarly, H2O2 production rates by both types of mitochondria were dose-dependently stimulated to the same extent by increasing concentrations of rotenone. We conclude that rotenone exerts similar effects on oxygen consumption and H2O2 production by isolated brain mitochondria from young-adult and old rats. Therefore, aging does not increase the mitochondrial H2O2 generation in response to complex I inhibition. PMID:25596437

  17. Effective protection of Terminalia catappa L. leaves from damage induced by carbon tetrachloride in liver mitochondria.

    PubMed

    Tang, Xinhui; Gao, Jing; Wang, Yanping; Fan, Yi-Mei; Xu, Li-Zhi; Zhao, Xiao-Ning; Xu, Qiang; Qian, Zhong Ming

    2006-03-01

    The protective effects of chloroform extracts of Terminalia catappa L. leaves (TCCE) on carbon tetrachloride (CCl4)-induced liver damage and the possible mechanisms involved in the protection were investigated in mice. We found that increases in the activity of serum aspartate aminotransferase and alanine aminotransferase and the level of liver lipid peroxidation (2.0-fold, 5.7-fold and 2.8-fold) induced by CCl4 were significantly inhibited by oral pretreatment with 20, 50 or 100 mg/kg of TCCE. Morphological observation further confirmed the hepatoprotective effects of TCCE. In addition, the disruption of mitochondrial membrane potential (14.8%), intramitochondrial Ca2+ overload (2.1-fold) and suppression of mitochondrial Ca2+-ATPase activity (42.0%) in the liver of CCl4-insulted mice were effectively prevented by pretreatment with TCCE. It can be concluded that TCCE have protective activities against liver mitochondrial damage induced by CCl4, which suggests a new mechanism of the hepatoprotective effects of TCCE. PMID:16169207

  18. Protoporphyrinogen oxidase: high affinity tetrahydrophthalimide radioligand for the inhibitor/herbicide-binding site in mouse liver mitochondria.

    PubMed

    Birchfield, N B; Casida, J E

    1996-01-01

    Protoporphyrinogen oxidase (protox), the last common enzyme in heme and chlorophyll biosynthesis, is the target of several classes of herbicides acting as inhibitors in both plants and mammals. N-(4-Chloro-2-fluoro-5-(propargyloxy)phenyl)-3,4,5,6-tetrahydro phthalimide (a potent protox inhibitor referred to as THP) was synthesized as a candidate radioligand ([3H]-THP) by selective catalytic reduction of 3,6-dihydrophthalic anhydride (DHPA) with tritium gas followed by condensation in 45% yield with 4-chloro-2-fluoro-5-(propargyloxy)aniline. Insertion of tritium at the 3 and 6 carbons of DHPA as well as the expected 4 and 5 carbons resulted in high specific activity [3H]THP (92 Ci/mmol). This radioligand undergoes rapid, specific, saturable, and reversible binding to the inhibitor/herbicide binding site of the protox component of cholate-solubilized mouse liver mitochondria with an apparent Kd of 0.41 nM and Bmax of 0.40 pmol/mg of protein. In the standard assay, mouse preparation (150 micrograms of protein) and [3H]THP (0.5 nM) are incubated in 500 microL of phosphate buffer at pH 7.2 for 15 min at 25 degrees C followed by addition of ammonium sulfate and filtration with glass fiber filters. The potencies of five nitrodiphenyl ethers and two other herbicides as inhibitors of [3H]THP binding correlate well with those for inhibition of protox activity (r2 = 0.97, n = 7), thus validating the binding assay as relevant to enzyme inhibition. It is also suitable to determine in vivo block as illustrated by an approximately 50% decrease in [3H]THP binding in liver mitochondria from mice treated ip with oxyfluorfen at 4 mg/kg. This is the first report of a binding assay for protox in mammals. The high affinity and specific activity of [3H]THP facilitate quantitation of protox and therefore research on a sensitive inhibition site for porphyrin biosynthesis. PMID:8902268

  19. A novel PGC-1α isoform in brain localizes to mitochondria and associates with PINK1 and VDAC

    SciTech Connect

    Choi, Joungil; Batchu, Vera Venkatanaresh Kumar; Schubert, Manfred; Castellani, Rudolph J.; Russell, James W.

    2013-06-14

    Highlights: •Novel 35 kDa PGC-1α localizes to mitochondrial inner membrane and matrix in brain. •Mitochondrial localization of 35 kDa PGC-1α depends on VDAC protein. •Mitochondrial localization of 35 kDa PGC-1α depends on membrane potential. •The 35 kDa PGC-1α associates and colocalizes with PINK in brain mitochondria. -- Abstract: Peroxisome proliferator-activated receptor-gamma co-activator 1α (PGC-1α) and PTEN-induced putative kinase 1 (PINK1) are powerful regulators of mitochondrial function. Here, we report that a previously unrecognized, novel 35 kDa PGC-1α isoform localizes to the mitochondrial inner membrane and matrix in brain as determined by protease protection and carbonate extraction assays, as well as by immunoelectron microscopy. Immunoelectron microscopy and import experiments in vitro revealed that 35 kDa PGC-1α colocalizes and interacts with the voltage-dependent anion channel (VDAC), and that its import depends on VDAC. Valinomycin treatment which depolarizes the membrane potential, abolished mitochondrial localization of the 35 kDa PGC-1α. Using blue native-PAGE, co-immunoprecipitation, and immunoelectron microscopy analyses, we found that the 35 kDa PGC-1α binds and colocalizes with PINK1 in brain mitochondria. This is the first report regarding mitochondrial localization of a novel 35 kDa PGC-1α isoform and its association with PINK1, suggesting possible regulatory roles for mitochondrial function in the brain.

  20. Effect of poly(amido)amine (PAMAM) G4 dendrimer on heart and liver mitochondria in an animal model of diabetes.

    PubMed

    Labieniec, Magdalena; Ulicna, Olga; Vancova, Olga; Kucharska, Jarmila; Gabryelak, Teresa; Watala, Cezary

    2010-01-01

    Diabetes-induced injury related to hyperglycaemia is associated with impaired function of mitochondria. Regardless of their cytotoxicity, PAMAM [poly(amido)amine] G4 dendrimers lower plasma glucose and suppress long-term markers of diabetic hyperglycaemia in experimental diabetes. In the present study, we aimed at verifying whether such modulatory effects of PAMAM G4 (0.5 micromol/kg of body weight daily for 60 days) may contribute to improved respiration in heart and liver mitochondria from streptozotocin-diabetic rats. PAMAM G4 alleviated long-term markers of hyperglycaemia and reduced blood and tissue lipophilic antioxidants in diabetic animals, but did not restore mitochondrial function. In hearts, but not livers, dendrimers further reduced respiratory function and oxidative phosphorylation. Thus ameliorating effects of PAMAM G4 on glycation and glycoxidation in experimental diabetes are not sufficient to restore the impaired mitochondrial function in diabetes. PMID:19947941

  1. Inhibition of ruthenium red-induced Ca2+ efflux from liver mitochondria by the antibiotic X-537A.

    PubMed

    Pereira da Silva, L; Bernardes, C F; Vercesi, A E

    1984-10-15

    It has been reported (Becker, G.L., Fiskum, G. and Lehninger, A.L. (1980) J. Biol. Chem. 255, 9009-9012) that respiring rat liver mitochondria suspended in KC1 medium containing ATP, Mg2+ and phosphate, maintain a steady state extramitochondrial free Ca2+ concentration of about 0.5 microM. The results reported here show that the addition of the antibiotic X-537A, at concentrations far below those required for ionophorous activity, caused a perturbation in this steady state, lowering the extramitochondrial free Ca2+ concentration by about 0.20 microM. This shift in steady state was clarified by a study of X-537A inhibition of the Ca2+ efflux induced by ruthenium red; a half-maximum effect was observed at approximately 25 nM X-537A. No effect on Ca2+ transport through the influx uniporter was observed. The possibility of a generalized stabilizing action of the antibiotic on the mitochondrial membrane seems to be ruled out by its effectiveness at very low concentrations. PMID:6208904

  2. Electron transport inhibition of the cytochrome bc1 complex of rat-liver mitochondria by phenolic uncouplers.

    PubMed

    Tokutake, N; Miyoshi, H; Fujita, T

    1991-05-01

    The respiration inhibition of rat-liver mitochondria by a series of substituted phenolic uncouplers was studied. The inhibitory effects were classified into three types, I-III, depending on the pattern of the changes in inhibitory potency observed when the potent uncoupler SF6847 was simultaneously applied. The extent of inhibition by type I phenols did not change as the transmembrane potential was dissipated by SF6847, but the extent of inhibition by type II and III phenols was decreased and increased, respectively. With the addition of another potent uncoupler, fluazinam, the uncoupling activity of which disappears with time, the inhibitory potency of type II phenols was decreased, but increased reversibly with the disappearance of the uncoupling effect of fluazinam. However, the inhibitory potency of type III phenols increased by fluazinam was not reduced. The inhibitory site of the phenols studied here was the cytochrome bc1 complex. This complex undergoes conformational changes when the transmembrane potential changes. The findings suggested that inhibition by substituted phenolic uncouplers depends partially on conformational changes of the cytochrome bc1 complex that accompany variations in the transmembrane potential. PMID:1851439

  3. Diet-Sensitive Sources of Reactive Oxygen Species in Liver Mitochondria: Role of Very Long Chain Acyl-CoA Dehydrogenases

    PubMed Central

    Cardoso, Ariel R.; Kakimoto, Pâmela A. H. B.; Kowaltowski, Alicia J.

    2013-01-01

    High fat diets and accompanying hepatic steatosis are highly prevalent conditions. Previous work has shown that steatosis is accompanied by enhanced generation of reactive oxygen species (ROS), which may mediate further liver damage. Here we investigated mechanisms leading to enhanced ROS generation following high fat diets (HFD). We found that mitochondria from HFD livers present no differences in maximal respiratory rates and coupling, but generate more ROS specifically when fatty acids are used as substrates. Indeed, many acyl-CoA dehydrogenase isoforms were found to be more highly expressed in HFD livers, although only the very long chain acyl-CoA dehydrogenase (VLCAD) was more functionally active. Studies conducted with permeabilized mitochondria and different chain length acyl-CoA derivatives suggest that VLCAD is also a source of ROS production in mitochondria of HFD animals. This production is stimulated by the lack of NAD+. Overall, our studies uncover VLCAD as a novel, diet-sensitive, source of mitochondrial ROS. PMID:24116206

  4. Effects of Treating Old Rats with an Aqueous Agaricus blazei Extract on Oxidative and Functional Parameters of the Brain Tissue and Brain Mitochondria

    PubMed Central

    de Sá-Nakanishi, Anacharis B.; Soares, Andréia A.; de Oliveira, Andrea Luiza; Fernando Comar, Jurandir; Peralta, Rosane M.; Bracht, Adelar

    2014-01-01

    Dysfunction of the mitochondrial respiratory chain and increased oxidative stress is a striking phenomenon in the brain of aged individuals. For this reason there has been a constant search for drugs and natural products able to prevent or at least to mitigate these problems. In the present study the effects of an aqueous extract of Agaricus blazei, a medicinal mushroom, on the oxidative state and on the functionality of mitochondria from the brain of old rats (21 months) were conducted. The extract was administered intragastrically during 21 days at doses of 200 mg/kg. The administration of the A. blazei extract was protective to the brain of old rats against oxidative stress by decreasing the lipid peroxidation levels and the reactive oxygen species content and by increasing the nonenzymic and enzymic antioxidant capacities. Administration of the A. blazei extract also increased the activity of several mitochondrial respiratory enzymes and, depending on the substrate, the mitochondrial coupled respiration. PMID:24876914

  5. Protections of SMND-309, a novel derivate of salvianolic acid B, on brain mitochondria contribute to injury amelioration in cerebral ischemia rats.

    PubMed

    Tian, Jingwei; Fu, Fenghua; Li, Guisheng; Gao, Yubai; Zhang, Yunjuan; Meng, Qingsheng; Li, Changlu; Liu, Fu

    2009-08-01

    SMND-309, a novel compound named (2E)-2-{6-[(E)-2-carboxylvinyl]-2,3-dihydroxyphenyl}-3-(3,4-dihydroxyphenyl) propenoic acid, is a new derivate of salvianolic acid B. The present study was conducted to investigate whether SMND-309 has a protective effect on brain injury after focal cerebral ischemia, and if it did so, to investigate its effects on brain mitochondria. Adult male SD rats were subjected to middle cerebral artery occlusion (MCAO) by bipolar electro-coagulation. Behavioral tests and brain patho-physiological tests were used to evaluate the damage to central nervous system. Origin targets including mitochondria production of reactive oxygen species, antioxidant potentia, membrane potential, energy metabolism, mitochondrial respiratory enzymes activities and mitochondria swelling degree were evaluated. The results showed that SMND-309 decreased neurological deficit scores, reduced the number of dead hippocampal neuronal cells in accordance with its depression on mitochondria swelling degree, reactive oxygen species production, improvements on mitochondria swelling, energy metabolism, membrane potential level and mitochondrial respiratory chain complex activities. All of these findings indicate that SMND-309 exerted potent neuroprotective effects in the model of permanent cerebral ischemia, contributed to its protections on brain mitochondrial structure and function. PMID:19481432

  6. Lichen acids as uncouplers of oxidative phosphorylation of mouse-liver mitochondria.

    PubMed

    Abo-Khatwa, A N; al-Robai, A A; al-Jawhari, D A

    1996-01-01

    Three lichen acids-namely, (+)usnic acid, vulpinic acid, and atranorin-were isolated from three lichen species (Usnea articulata, Letharia vulpina, and Parmelia tinctorum, respectively). The effects of these lichen products on mice-liver mitochondrial oxidative functions in various respiratory states and on oxidative phosphorylation were studied polarographically in vitro. The lichen acids exhibited characteristics of the 2,4-dinitrophenol (DNP), a classical uncoupler of oxidative phosphorylation. Thus, they released respiratory control and oligomycin inhibited respiration, hindered ATP synthesis, and enhanced Mg(+2)-ATPase activity. (+)Usnic acid at a concentration of 0.75 microM inhibited ADP/O ratio by 50%, caused maximal stimulation of both state-4 respiration (100%) and ATPase activity (300%). Atranorin was the only lichen acid with no significant effect on ATPase. The uncoupling effect was dose-dependent in all cases. The minimal concentrations required to cause complete uncoupling of oxidative phosphorylation were as follows: (+)usnic acid (1 microM), vulpinic acid, atranorin (5 microM) and DNP (50 microM). It was postulated that the three lichen acids induce uncoupling by acting on the inner mitochondrial membrane through their lipophilic properties and protonophoric activities. PMID:8726330

  7. Papyriferic acid, an antifeedant triterpene from birch trees, inhibits succinate dehydrogenase from liver mitochondria.

    PubMed

    McLean, Stuart; Richards, Stephen M; Cover, Siow-Leng; Brandon, Sue; Davies, Noel W; Bryant, John P; Clausen, Thomas P

    2009-10-01

    Papyriferic acid (PA) is a triterpene that is secreted by glands on twigs of the juvenile ontogenetic phase of resin producing tree birches (e.g., Betula neoalaskana, B. pendula) and that deters browsing by mammals such as the snowshoe hare (Lepus americanus). We investigated the pharmacology of PA as a first step in understanding its antifeedant effect. After oral administration to rats, PA and several metabolites were found in feces but not urine, indicating that little was absorbed systemically. Metabolism involved various combinations of hydrolysis of its acetyl and malonyl ester groups, and hydroxylation of the terpene moiety. The presence of a malonyl group suggested a possible interaction with succinate dehydrogenase (SDH), a mitochondrial enzyme known to be competitively inhibited by malonic acid. The effect of PA on the oxidation of succinate by SDH was examined in mitochondrial preparations from livers of ox, rabbit, and rat. In all three species, PA was a potent inhibitor of SDH. Kinetic analysis indicated that, unlike malonate, PA acted by an uncompetitive mechanism, meaning that it binds to the enzyme-substrate complex. The hydrolysis product of PA, betulafolienetriol oxide, was inactive on SDH. Overall, the evidence suggests that PA acts as the intact molecule and interacts at a site other than the succinate binding site, possibly binding to the ubiquinone sites on complex II. Papyriferic acid was potent (K(iEIS) ranged from 25 to 45 microM in the three species) and selective, as malate dehydrogenase was unaffected. Although rigorous proof will require further experiments, we have a plausible mechanism for the antifeedant effect of PA: inhibition of SDH in gastrointestinal cells decreases mitochondrial energy production resulting in a noxious stimulus, 5-HT release, and sensations of nausea and discomfort. There is evidence that the co-evolution of birches and hares over a large and geographically-diverse area in Northern Europe and America has

  8. Neuronal hemoglobin in mitochondria is reduced by forming a complex with α-synuclein in aging monkey brains

    PubMed Central

    Yang, Weiwei; Li, Xuran; Li, Xin; Li, Xuying; Yu, Shun

    2016-01-01

    Neuronal hemoglobin (nHb) plays a critical role in maintaining normal mitochondrial functioning in the brain. However, in aging and Parkinson's disease (PD) brains, mitochondrial nHb levels are greatly reduced in neurons that accumulate α-synuclein (α-syn), suggesting a link between the two proteins. In this study, we demonstrate that α-syn and Hb can form a complex in both brain tissue and peripheral red blood cells (RBCs) in aging cynomolgus monkeys. nHb-α-syn complex levels in the mitochondrial fraction of the striatum decreased with age; this was negatively correlated with levels in the cytoplasmic fraction and in RBCs and was accompanied by a reduction in mitochondrial free nHb. In contrast, no changes in nHb-α-syn complex formation or free nHb levels were detected in the cerebellum. In vitro studies using a cultured dopaminergic cell line showed that intracellular accumulation of α-syn caused an elevation in nHb-α-syn complex levels in both mitochondrial and cytoplasmic fractions as well as a reduction in mitochondrial free nHb. nHb overexpression increased free nHb levels in mitochondria, stabilized mitochondrial membrane potential, and reduced α-syn-induced apoptosis. The above results suggest that α-syn forms a complex with nHb in selected regions of the aging brain, thereby decreasing mitochondrial function and increasing the risk of PD. PMID:26824991

  9. Coenzyme Q10 remarkably improves the bio-energetic function of rat liver mitochondria treated with statins.

    PubMed

    Mohammadi-Bardbori, Afshin; Najibi, Asma; Amirzadegan, Najmeh; Gharibi, Raziyeh; Dashti, Ayat; Omidi, Mahmoud; Saeedi, Arastoo; Ghafarian-Bahreman, Ali; Niknahad, Hossein

    2015-09-01

    CoQ10 shares a biosynthetic pathway with cholesterol therefore it can be a potential target of the widely available lipid-lowering agents such as statins. Statins are the most widely prescribed cholesterol-lowering drugs with the ability to inhibit HMG-CoA (3-hydroxy-3-methylglutaryl-coenzyme A) reductase. Preclinical and clinical safety data have shown that statins do not cause serious adverse effects in humans. However, their long-term administration is associated with a variety of myopatic complaints. The aim of this study was to investigate whether CoQ10 supplementation of animals under high fat diet (HFD) treated with statins is able to bypass the mitochondrial metabolic defects or not? Animals were divided into 7 groups and fed with either regular (RD) or HFD during experiments. The first group considered as regular control and fed with a RD. Groups 2-7 including HFD control, CoQ10 (10mg/kg), simvastatin (30mg/kg), atorvastatin (30mg/kg), simvastatin+CoQ10 or atorvastatin+CoQ10 treated orally for 30 days and fed with HFD. At the end of treatments, the animals were killed and blood samples were collected for biochemical examinations. The rat liver mitochondria were isolated and several mitochondrial indices including succinate dehydrogenase activity (SDA), ATP levels, mitochondrial membrane potential (MMP) and mitochondrial permeability transition pore (MPP) were determined. We found that triglyceride (Tg), cholesterol (Chol) and low-density lipoprotein (LDL) were augmented with HFD compared to RD and treatment with statins remarkably lowered the Tg, Chol and LDL levels. Mitochondrial parameters including, SDA, ATP levels, MMP and MPP were reduced with statin treatment and improved by co-administration with CoQ10. PMID:26007644

  10. [Activity of oil isolated from Amaranth seeds on energetic functions of rat liver mitochondria after adrenaline introduction].

    PubMed

    Sirota, T V; Eliseeva, O P; Khunderiakova, N V; Kaminskiĭ, D V; Makhotina, O A; Kondrashova, M N

    2007-01-01

    It has been shown that a three-week feeding of rats with oil derived from seeds of amaranth (Amaranthus cruentus L.) leads to a moderate activation of respiration of coupled and uncoupled rat liver mitochondria (MCh) that oxidize succinate and succinate + glutamate, as well as alpha-ketoglutarate and alpha-ketoglutarate + malonate. In animals receiving the amaranth oil, the injection of adrenaline did not affect the oil-activated respiration of MCh during succinate oxidation; i. e., animals prepared by an oil-enriched diet were resistant to the action of adrenaline, which prevented from possible hyperactivation of mitochondrial functions. In the group of control animals, which received no oil, the injection of adrenaline activated the rate of phosphorylating respiration of MCh during oxidation of succinate or succinate + glutamate: the rate of oxygen uptake in state 3 respiration (by Chance) increased, and the phosphorylation time decreased. The injection of adrenaline did not affect the parameters of respiration of MCh that oxidize a-ketoglutarate; however, in the presence of malonate, the oxidation of alpha-ketoglutarate in state 3 and uncoupled respiration have shown mild but significant increase in response to adrenaline. In animals receiving the amaranth oil, the oil-induced activation of respiration of MCh in response to adrenaline retained but did not increase; however, the phosphorylation time significantly decreased. Thus, concentrated oil of seeds activates the respiration of MCh. In addition, it enhances an energetic function of MCh, which prevents from the hyper-activation of mitochondrial respiration by adrenaline. Therefore an activation of energetic function of MCh by amaranth oil could explain its adaptogenic effect on rats. PMID:18357794

  11. Mitochondria in White, Brown, and Beige Adipocytes

    PubMed Central

    Cedikova, Miroslava; Kripnerová, Michaela; Dvorakova, Jana; Pitule, Pavel; Grundmanova, Martina; Babuska, Vaclav; Mullerova, Dana; Kuncova, Jitka

    2016-01-01

    Mitochondria play a key role in energy metabolism in many tissues, including cardiac and skeletal muscle, brain, liver, and adipose tissue. Three types of adipose depots can be identified in mammals, commonly classified according to their colour appearance: the white (WAT), the brown (BAT), and the beige/brite/brown-like (bAT) adipose tissues. WAT is mainly involved in the storage and mobilization of energy and BAT is predominantly responsible for nonshivering thermogenesis. Recent data suggest that adipocyte mitochondria might play an important role in the development of obesity through defects in mitochondrial lipogenesis and lipolysis, regulation of adipocyte differentiation, apoptosis, production of oxygen radicals, efficiency of oxidative phosphorylation, and regulation of conversion of white adipocytes into brown-like adipocytes. This review summarizes the main characteristics of each adipose tissue subtype and describes morphological and functional modifications focusing on mitochondria and their activity in healthy and unhealthy adipocytes. PMID:27073398

  12. Effects of age, dietary, and behavioral enrichment on brain mitochondria in a canine model of human aging.

    PubMed

    Head, E; Nukala, V N; Fenoglio, K A; Muggenburg, B A; Cotman, C W; Sullivan, P G

    2009-11-01

    Dogs develop cognitive decline and a progressive accumulation of oxidative damage. In a previous longitudinal study, we demonstrated that aged dogs treated with either an antioxidant diet or with behavioral enrichment show cognitive improvement. The antioxidant diet included cellular antioxidants (vitamins E and C, fruits and vegetables) and mitochondrial cofactors (lipoic acid and carnitine). Behavioral enrichment consisted of physical exercise, social enrichment, and cognitive training. We hypothesized that the antioxidant treatment improved neuronal function through increased mitochondrial function. Thus, we measured reactive oxygen species (ROS) production and bioenergetics in mitochondria isolated from young, aged, and treated aged animals. Aged canine brain mitochondria show significant increases in ROS production and a reduction in NADH-linked respiration. Mitochondrial function (ROS and NADH-linked respiration) was improved selectively in aged dogs treated with an antioxidant diet. In contrast, behavioral enrichment had no effect on any mitochondrial parameters. These results suggest that an antioxidant diet improves cognition by maintaining mitochondrial homeostasis, which may be an independent molecular pathway not engaged by behavioral enrichment. PMID:19703441

  13. Resveratrol Directly Binds to Mitochondrial Complex I and Increases Oxidative Stress in Brain Mitochondria of Aged Mice

    PubMed Central

    Chupin, Stéphanie; Baron, Stéphanie; Nivet-Antoine, Valérie; Vessières, Emilie; Ayer, Audrey; Henrion, Daniel; Lenaers, Guy; Reynier, Pascal; Procaccio, Vincent

    2015-01-01

    Resveratrol is often described as a promising therapeutic molecule for numerous diseases, especially in metabolic and neurodegenerative disorders. While the mechanism of action is still debated, an increasing literature reports that resveratrol regulates the mitochondrial respiratory chain function. In a recent study we have identified mitochondrial complex I as a direct target of this molecule. Nevertheless, the mechanisms and consequences of such an interaction still require further investigation. In this study, we identified in silico by docking study a binding site for resveratrol at the nucleotide pocket of complex I. In vitro, using solubilized complex I, we demonstrated a competition between NAD+ and resveratrol. At low doses (<5μM), resveratrol stimulated complex I activity, whereas at high dose (50 μM) it rather decreased it. In vivo, in brain mitochondria from resveratrol treated young mice, we showed that complex I activity was increased, whereas the respiration rate was not improved. Moreover, in old mice with low antioxidant defenses, we demonstrated that complex I activation by resveratrol led to oxidative stress. These results bring new insights into the mechanism of action of resveratrol on mitochondria and highlight the importance of the balance between pro- and antioxidant effects of resveratrol depending on its dose and age. These parameters should be taken into account when clinical trials using resveratrol or analogues have to be designed. PMID:26684010

  14. Combined effect of G3139 and TSPO ligands on Ca(2+)-induced permeability transition in rat brain mitochondria.

    PubMed

    Azarashvili, T; Krestinina, O; Baburina, Yu; Odinokova, I; Grachev, D; Papadopoulos, V; Akatov, V; Lemasters, J J; Reiser, G

    2015-12-01

    Permeability of the mitochondrial outer membrane is determined by the activity of voltage-dependent anion channels (VDAC) which are regulated by many factors and proteins. One of the main partner-regulator of VDAC is the 18 kDa translocator protein (TSPO), whose role in the regulation of membrane permeability is not completely understood. We show that TSPO ligands, 1 μM PPIX and PK11195 at concentrations of 50 μM, accelerate opening of permeability transition pores (mPTP) in Ca(2+)-overloaded rat brain mitochondria (RBM). By contrast, PK11195 at 100 nM and anti-TSPO antibodies suppressed pore opening. Participation of VDAC in these processes was demonstrated by blocking VDAC with G3139, an 18-mer phosphorothioate oligonucleotides, which sensitized mitochondria to Ca(2+)-induced mPTP opening. Despite the inhibitory effect of 100 nM PK11195 and anti-TSPO antibodies alone, their combination with G3139 considerably stimulated the mPTP opening. Thus, 100 nM PK11195 and anti-TSPO antibody can modify permeability of the VDAC channel and mPTP. When VDAC channels are closed and TSPO is blocked, permeability of the VDAC for calcium seems to be the highest, which leads to accelerated pore opening. PMID:26498031

  15. Combined effect of G3139 and TSPO ligands on Ca2+-induced permeability transition in rat brain mitochondria

    PubMed Central

    Azarashvili, T.; Krestinina, O.; Baburina, Yu; Odinokova, I.; Grachev, D.; Papadopoulos, V.; Akatov, V.; Lemasters, J.J.; Reiser, G.

    2016-01-01

    Permeability of the mitochondrial outer membrane is determined by the activity of voltage-dependent anion channels (VDAC) which are regulated by many factors and proteins. One of the main partner-regulator of VDAC is the 18 kDa translocator protein (TSPO), whose role in the regulation of membrane permeability is not completely understood. We show that TSPO ligands, 1 μM PPIX and PK11195 at concentrations of 50 μM, accelerate opening of permeability transition pores (mPTP) in Ca2+-overloaded rat brain mitochondria (RBM). By contrast, PK11195 at 100 nM and anti-TSPO antibodies suppressed pore opening. Participation of VDAC in these processes was demonstrated by blocking VDAC with G3139, an 18-mer phosphorothioate oligonucleotides, which sensitized mitochondria to Ca2+-induced mPTP opening. Despite the inhibitory effect of 100 nM PK11195 and anti-TSPO antibodies alone, their combination with G3139 considerably stimulated the mPTP opening. Thus, 100 nM PK11195 and anti-TSPO antibody can modify permeability of the VDAC channel and mPTP. When VDAC channels are closed and TSPO is blocked, permeability of the VDAC for calcium seems to be the highest, which leads to accelerated pore opening. PMID:26498031

  16. Evaluation of some Mannich bases derived from substituted acetophenones against P-388 lymphocytic leukemia and on respiration in isolated rat liver mitochondria.

    PubMed

    Dimmock, J R; Shyam, K; Hamon, N W; Logan, B M; Raghavan, S K; Harwood, D J; Smith, P J

    1983-08-01

    Series of 3-dimethylamino-1-aryl-1-propanone hydrobromides (IV) and 3-dimethylamino-2-dimethylaminomethyl-1-aryl-1-propanone dihydrobromides (V) were synthesized. Evaluation of these derivatives against P-388 lymphocytic leukemia growth revealed that two compounds show promise as antineoplastic agents. Compounds of the V series were unstable in phosphate buffer (in contrast to series IV), and when the same nuclear substituent was present in both series of compounds, V was approximately 100 times more active than IV in both the stimulation and inhibition of respiration of mitochondria isolated from rat liver cells. Representatives from both series showed that respiration in mitochondria was affected by changing the pH of the aqueous buffer from 7.4 to 6.9 or 6.4 and by reducing the temperature from 37 degrees to 20 degrees. The compounds showed reactivity toward a biomimetic thiol. PMID:6620142

  17. Antibodies to cannabinoid type 1 receptor co-react with stomatin-like protein 2 in mouse brain mitochondria.

    PubMed

    Morozov, Yury M; Dominguez, Martin H; Varela, Luis; Shanabrough, Marya; Koch, Marco; Horvath, Tamas L; Rakic, Pasko

    2013-08-01

    Anti-cannabinoid type 1 receptor (CB1 ) polyclonal antibodies are widely used to detect the presence of CB1 in a variety of brain cells and their organelles, including neuronal mitochondria. Surprisingly, we found that anti-CB1 sera, in parallel with CB1 , also recognize the mitochondrial protein stomatin-like protein 2. In addition, we show that the previously reported effect of synthetic cannabinoid WIN 55,212-2 on mitochondrial complex III respiration is not detectable in purified mitochondrial preparations. Thus, our study indicates that a direct relationship between endocannabinoid signaling and mitochondrial functions in the cerebral cortex seems unlikely, and that caution should be taken interpreting findings obtained using anti-CB1 antibodies. PMID:23617247

  18. Selective Toxicity of Persian Gulf Sea Cucumber (Holothuria parva) and Sponge (Haliclona oculata) Methanolic Extracts on Liver Mitochondria Isolated from an Animal Model of Hepatocellular Carcinoma

    PubMed Central

    Seydi, Enayatollah; Motallebi, Abbasali; Dastbaz, Maryam; Dehghan, Sahar; Salimi, Ahmad; Nazemi, Melika; Pourahmad, Jalal

    2015-01-01

    Background: Natural products isolated from marine environments are well known for their pharmacodynamic potential in diverse disease treatments, such as for cancer or inflammatory conditions. Sea cucumbers are marine animals of the phylum Echinoderm and the class Holothuroidea, with leathery skin and gelatinous bodies. Sponges are important components of Persian Gulf animal communities, and the marine sponges of the genus Haliclona have been known to display broad-spectrum biological activity. Many studies have shown that sea cucumbers and sponges contain antioxidants and anti-cancer compounds. Objectives: This study was designed to determine the selective toxicity of Persian Gulf sea cucumber (Holothuria parva) and sponge (Haliclona oculata) methanolic extracts on liver mitochondria isolated from an animal model of hepatocellular carcinoma, as part of a national project that hopes to identify novel potential anticancer candidates among Iranian Persian Gulf flora and fauna. Materials and Methods: To induce hepatocarcinogenesis, rats were given diethylnitrosamine (DEN) injections (200 mg/kg i.p. by a single dose), and then the cancer was promoted with 2-acetylaminofluorene (2-AAF) (0.02 w/w) for two weeks. Histopathological evaluations were performed, and levels of liver injury markers and a specific liver cancer marker (alpha-fetoprotein), were determined for confirmation of hepatocellular carcinoma induction. Finally, mitochondria were isolated from cancerous and non-cancerous hepatocytes. Results: Our results showed that H. parva methanolic extracts (250, 500, and 1000 µg/mL) and H. oculata methanolic extracts (200, 400, and 800 µg/mL) increased reactive oxygen species (ROS) formation, mitochondrial membrane potential (MMP), mitochondrial swelling, and cytochrome c release in the mitochondria obtained from cancerous hepatocytes, but not in mitochondria obtained from non-cancerous liver hepatocytes. These extracts also induced caspase-3 activation, which is

  19. cis-4-Decenoic and decanoic acids impair mitochondrial energy, redox and Ca(2+) homeostasis and induce mitochondrial permeability transition pore opening in rat brain and liver: Possible implications for the pathogenesis of MCAD deficiency.

    PubMed

    Amaral, Alexandre Umpierrez; Cecatto, Cristiane; da Silva, Janaína Camacho; Wajner, Alessandro; Godoy, Kálita Dos Santos; Ribeiro, Rafael Teixeira; Wajner, Moacir

    2016-09-01

    Medium-chain acyl-CoA dehydrogenase (MCAD) deficiency is biochemically characterized by tissue accumulation of octanoic (OA), decanoic (DA) and cis-4-decenoic (cDA) acids, as well as by their carnitine by-products. Untreated patients present episodic encephalopathic crises and biochemical liver alterations, whose pathophysiology is poorly known. We investigated the effects of OA, DA, cDA, octanoylcarnitine (OC) and decanoylcarnitine (DC) on critical mitochondrial functions in rat brain and liver. DA and cDA increased resting respiration and diminished ADP- and CCCP-stimulated respiration and complexes II-III and IV activities in both tissues. The data indicate that these compounds behave as uncouplers and metabolic inhibitors of oxidative phosphorylation. Noteworthy, metabolic inhibition was more evident in brain as compared to liver. DA and cDA also markedly decreased mitochondrial membrane potential, NAD(P)H content and Ca(2+) retention capacity in Ca(2+)-loaded brain and liver mitochondria. The reduction of Ca(2+) retention capacity was more pronounced in liver and totally prevented by cyclosporine A and ADP, as well as by ruthenium red, demonstrating the involvement of mitochondrial permeability transition (mPT) and Ca(2+). Furthermore, cDA induced lipid peroxidation in brain and liver mitochondria and increased hydrogen peroxide formation in brain, suggesting the participation of oxidative damage in cDA-induced alterations. Interestingly, OA, OC and DC did not alter the evaluated parameters, implying lower toxicity for these compounds. Our results suggest that DA and cDA, in contrast to OA and medium-chain acylcarnitines, disturb important mitochondrial functions in brain and liver by multiple mechanisms that are possibly involved in the neuropathology and liver alterations observed in MCAD deficiency. PMID:27240720

  20. Effect of thyroid state on enzymatic and non-enzymatic processes in H2O2 removal by liver mitochondria of male rats.

    PubMed

    Venditti, P; Napolitano, G; Barone, D; Coppola, I; Di Meo, S

    2015-03-01

    We investigated thyroid state effect on capacity of rat liver mitochondria to remove exogenously produced H2O2, determining their ability to decrease fluorescence generated by an H2O2 detector system. The rate of H2O2 removal by both non respiring and respiring mitochondria was increased by hyperthyroidism and decreased by hypothyroidism. However, the rate was higher in the presence of respiratory substrates, in particular pyruvate/malate, indicating a respiration-dependent process. Generally, the changes in H2O2 removal rates mirrored those in H2O2 release rates excluding the possibility that endogenous and exogenous H2O2 competed for the removing system. Pharmacological inhibition revealed thyroid state-linked differences in antioxidant enzyme contribution to H2O2 removal which were consistent with those in antioxidant system activities. The H2O2 removal was only in part due to enzymatic systems and that imputable to non-enzymatic processes was higher in hyperthyroid and lower in hypothyroid mitochondria. The levels of cytochrome c and the light emissions, due to luminol oxidation catalyzed by cytochrome/H2O2, exhibited similar changes with thyroid state supporting the idea that non-enzymatic scavenging was mainly due to hemoprotein action, which produces hydroxyl radicals. Further support was obtained showing that the whole antioxidant capacity, which provides an evaluation of capacity of the systems, different from cytochromes, assigned to H2O2 scavenging, was lower in hyperthyroid than in hypothyroid state. In conclusion, our results show that mitochondria from hyperthyroid liver have a high capacity for H2O2 removal, which, however, leading in great part to more reactive oxygen species, results harmful for such organelles. PMID:25597632

  1. Cardiolipin-mediated procoagulant activity of mitochondria contributes to traumatic brain injury-associated coagulopathy in mice.

    PubMed

    Zhao, Zilong; Wang, Min; Tian, Ye; Hilton, Tristan; Salsbery, Breia; Zhou, Eric Z; Wu, Xiaoping; Thiagarajan, Perumal; Boilard, Eric; Li, Min; Zhang, Jianning; Dong, Jing-Fei

    2016-06-01

    Cardiolipin (CL) is an anionic phospholipid located exclusively in the mitochondrial inner membrane. Its presence in blood indicates mitochondrial damage and release from injured cells. Here, we report the detection of CL-exposed brain-derived mitochondrial microparticles (mtMPs) at 17 547 ± 2677/μL in the peripheral blood of mice subjected to fluid percussion injury to the brain. These mtMPs accounted for 55.2% ± 12.6% of all plasma annexin V-binding microparticles found in the acute phase of injury. They were also released from cultured neuronal and glial cells undergoing apoptosis. The mtMPs synergized with platelets to facilitate vascular leakage by disrupting the endothelial barrier. The disrupted endothelial barrier allowed the release of mtMPs into the systemic circulation to promote coagulation in both traumatically injured and mtMP- or CL-injected mice, leading to enhanced fibrinolysis, vascular fibrin deposition, and thrombosis. This mtMP-induced coagulation was mediated by CL transported from the inner to the outer mitochondrial membrane and was blocked by the scavenging molecule lactadherin. The mtMP-bound CL was ∼1600 times as active as purified CL in promoting coagulation. This study uncovered a novel procoagulant activity of CL and CL-exposed mitochondria that may contribute to traumatic brain injury-associated coagulopathy and identified potential pathways to block this activity. PMID:27002118

  2. Hepatic IGFBP1 is a prosurvival factor that binds to BAK, protects the liver from apoptosis, and antagonizes the proapoptotic actions of p53 at mitochondria

    PubMed Central

    Leu, J. I-Ju; George, Donna L.

    2007-01-01

    Liver is generally refractory to apoptosis induced by the p53 tumor suppressor protein, but the molecular basis remains poorly understood. Here we show that p53 transcriptional activation leads to enhanced expression of hepatic IGFBP1 (insulin-like growth factor-binding protein-1). Exhibiting a previously unanticipated role, a portion of intracellular IGFBP1 protein localizes to mitochondria where it binds to the proapoptotic protein BAK and hinders BAK activation and apoptosis induction. Interestingly, in many cells and tissues p53 also has a direct apoptotic function at mitochondria that includes BAK binding and activation. When IGFBP1 is in a complex with BAK, formation of a proapoptotic p53/BAK complex and apoptosis induction are impaired, both in cultured cells and in liver. In contrast, livers of IGFBP1-deficient mice exhibit spontaneous apoptosis that is accompanied by p53 mitochondrial accumulation and evidence of BAK oligomerization. These data support the importance of BAK as a mediator of p53’s mitochondrial function. The results also identify IGFBP1 as a negative regulator of the BAK-dependent pathway of apoptosis, whose expression integrates the transcriptional and mitochondrial functions of the p53 tumor suppressor protein. PMID:18056423

  3. Data supporting the involvement of the adenine nucleotide translocase conformation in opening the Tl(+)-induced permeability transition pore in Ca(2+)-loaded rat liver mitochondria.

    PubMed

    Korotkov, Sergey M

    2016-06-01

    There we made available information about the effects of the adenine nucleotide translocase (ANT) 'c' conformation fixers (phenylarsine oxide (PAO), tert-butylhydroperoxide (tBHP), and carboxyatractyloside) as well as thiol reagent (4,4'-diisothiocyanostilbene-2,2'-disulfonate (DIDS)) on isolated rat liver mitochondria. We observed a decrease in A540 (mitochondrial swelling) and respiratory control rates (RCRADP [state 3/state 4] and RCRDNP [2,4-dinitrophenol-uncoupled state/basal state or state 4]), as well as an increase in Ca(2+)-induced safranin fluorescence (F485/590, arbitrary units), showed a dissipation in the inner membrane potential (ΔΨmito), in experiments with energized rat liver mitochondria, injected into the buffer containing 25-75 mM TlNO3, 125 mM KNO3, and 100 µM Ca(2+). The fixers and DIDS, in comparison to Ca(2+) alone, greatly increased A540 decline and the rate of Ca(2+)-induced ΔΨmito dissipation. These reagents also markedly decreased RCRADP and RCRDNP. The MPTP inhibitors (ADP, cyclosporin A, bongkrekic acid, and N-ethylmaleimide) fixing the ANT in 'm' conformation significantly hindered the above-mentioned effects of the fixers and DIDS. A more complete scientific analysis of these findings may be obtained from the manuscript "To involvement the conformation of the adenine nucleotide translocase in opening the Tl(+)-induced permeability transition pore in Ca(2+)-loaded rat liver mitochondria" (Korotkov et al., 2016 [1]). PMID:27054168

  4. Effects of DL-2-bromopalmitoyl-CoA and bromoacetyl-CoA in rat liver and heart mitochondria. Inhibition of carnitine palmitoyltransferase and displacement of [14C]malonyl-CoA from mitochondrial binding sites.

    PubMed Central

    Edwards, M R; Bird, M I; Saggerson, E D

    1985-01-01

    The overt form of carnitine palmitoyltransferase (CPT1) in rat liver and heart mitochondria was inhibited by DL-2-bromopalmitoyl-CoA and bromoacetyl-CoA. S-Methanesulphonyl-CoA inhibited liver CPT1. The inhibitory potency of DL-2-bromopalmitoyl-CoA was 17 times greater with liver than with heart CPT1. Inhibition of CPT1 by DL-2-bromopalmitoyl-CoA was unaffected by 5,5'-dithiobis-(2-nitrobenzoic acid) or (in liver) by starvation. In experiments in which DL-2-bromopalmitoyl-CoA displaced [14C]malonyl-CoA bound to liver mitochondria, the KD (competing) was 25 times the IC50 for inhibition of CPT1 providing evidence that the malonyl-CoA-binding site is unlikely to be the same as the acyl-CoA substrate site. Bromoacetyl-CoA inhibition of CPT1 was more potent in heart than in liver mitochondria and was diminished by 5,5'-dithiobis-(2-nitrobenzoic acid) or (in liver) by starvation. Bromoacetyl-CoA displaced bound [14C]malonyl-CoA from heart and liver mitochondria. In heart mitochondria this displacement was competitive with malonyl-CoA and was considerably facilitated by L-carnitine. In liver mitochondria this synergism between carnitine and bromoacetyl-CoA was not observed. It is suggested that bromoacetyl-CoA interacts with the malonyl-CoA-binding site of CPT1. L-Carnitine also facilitated the displacement by DL-2-bromopalmitoyl-CoA of [14C]malonyl-CoA from heart, but not from liver, mitochondria. DL-2-Bromopalmitoyl-CoA and bromoacetyl-CoA also inhibited overt carnitine octanoyl-transferase in liver and heart mitochondria. These findings are discussed in relation to inter-tissue differences in (a) the response of CPT1 activity to various inhibitors and (b) the relationship between high-affinity malonyl-CoA-binding sites and those sites for binding of L-carnitine and acyl-CoA substrates. PMID:4052034

  5. Cocaine and mitochondria-related signaling in the brain: A mechanistic view and future directions.

    PubMed

    de Oliveira, Marcos Roberto; Jardim, Fernanda Rafaela

    2016-01-01

    Cocaine is extensively used as a psychostimulant among subjects at different ages worldwide. Cocaine causes neuronal dysfunction and, consequently, negatively affects human behavior and decreases life quality severely. Cocaine acts through diverse mechanisms, including mitochondrial impairment and activation of cell signaling pathways associated to stress response. There is some controversy regarding the effect of cocaine in inducing cell death through apoptosis in different experimental models. The aim of the present work is to discuss data associated to the mitochondrial consequences of cocaine exposure of mammalian cells in several experimental models from in vitro to in vivo, including postmortem human tissue analyses. Furthermore, future directions are proposed in order to serve as a suggestive guide in relation to the next steps towards the complete elucidation of the mechanisms of toxicity elicited by cocaine upon mitochondria of neuronal cells. PMID:26707813

  6. Accumulation of oxidative DNA damage in brain mitochondria in mouse model of hereditary ferritinopathy.

    PubMed

    Deng, Xiaoling; Vidal, Ruben; Englander, Ella W

    2010-07-19

    Tissue iron content is strictly regulated to concomitantly satisfy specialized metabolic requirements and avoid toxicity. Ferritin, a multi-subunit iron storage protein, is central to maintenance of iron homeostasis in the brain. Mutations in the ferritin light chain (FTL)-encoding gene underlie the autosomal dominant, neurodegenerative disease, neuroferritinopathy/hereditary ferritinopathy (HF). HF is characterized by progressive accumulation of ferritin and iron. To gain insight into mechanisms by which FTL mutations promote neurodegeneration, a transgenic mouse, expressing human mutant form of FTL, was recently generated. The FTL mouse exhibits buildup of iron in the brain and presents manifestations of oxidative stress reminiscent of the human disease. Here, we asked whether oxidative DNA damage accumulates in the FTL mouse brain. Long-range PCR (L-PCR) amplification-mediated DNA damage detection assays revealed that the integrity of mitochondrial DNA (mtDNA) in the brain was significantly compromised in the 12- but not 6-month-old FTL mice. Furthermore, L-PCR employed in conjunction with DNA modifying enzymes, which target specific DNA adducts, revealed the types of oxidative adducts accumulating in mtDNA in the FTL brain. Consistently with DNA damage predicted to form under conditions of excessive oxidative stress, detected adducts include, oxidized guanines, abasic sites and strand breaks. Elevated mtDNA damage may impair mitochondrial function and brain energetics and in the long term contribute to neuronal loss and exacerbate neurodegeneration in HF. PMID:20478358

  7. Cardiolipin and electron transport chain abnormalities in mouse brain tumor mitochondria: lipidomic evidence supporting the Warburg theory of cancer*

    PubMed Central

    Kiebish, Michael A.; Han, Xianlin; Cheng, Hua; Chuang, Jeffrey H.; Seyfried, Thomas N.

    2008-01-01

    Otto Warburg first proposed that cancer originated from irreversible injury to mitochondrial respiration, but the structural basis for this injury has remained elusive. Cardiolipin (CL) is a complex phospholipid found almost exclusively in the inner mitochondrial membrane and is intimately involved in maintaining mitochondrial functionality and membrane integrity. Abnormalities in CL can impair mitochondrial function and bioenergetics. We used shotgun lipidomics to analyze CL content and composition in highly purified brain mitochondria from the C57BL/6J (B6) and VM/Dk (VM) inbred strains and from subcutaneously grown brain tumors derived from these strains to include an astrocytoma and ependymoblastoma (B6 tumors), a stem cell tumor, and two microgliomas (VM tumors). Major abnormalities in CL content or composition were found in all tumors. The compositional abnormalities involved an abundance of immature molecular species and deficiencies of mature molecular species, suggesting major defects in CL synthesis and remodeling. The tumor CL abnormalities were also associated with significant reductions in both individual and linked electron transport chain activities. A mathematical model was developed to facilitate data interpretation. The implications of our findings to the Warburg cancer theory are discussed. PMID:18703489

  8. Evolution of energy metabolism. Proton permeability of the inner membrane of liver mitochondria is greater in a mammal than in a reptile.

    PubMed

    Brand, M D; Couture, P; Else, P L; Withers, K W; Hulbert, A J

    1991-04-01

    Standard metabolic rate is 7-fold greater in the rat (a typical mammal) than in the bearded dragon, Amphibolurus vitticeps (a reptile with the same body mass and temperature). Rat hepatocytes respire 4-fold faster than do hepatocytes from the lizard. The inner membrane of isolated rat liver mitochondrial has a proton permeability that is 4-5-fold greater than the proton permeability of the lizard liver mitochondrial membrane per mg of mitochondrial protein. The greater permeability of rat mitochondria is not caused by differences in the surface area of the mitochondrial inner membrane, but differences in the fatty acid composition of the mitochondrial phospholipids may be involved in the permeability differences. Greater proton permeability of the mitochondrial inner membrane may contribute to the greater standard metabolic rate of mammals. PMID:1850242

  9. Weak mitochondrial targeting sequence determines tissue-specific subcellular localization of glutamine synthetase in liver and brain cells.

    PubMed

    Matthews, Gideon D; Gur, Noa; Koopman, Werner J H; Pines, Ophry; Vardimon, Lily

    2010-02-01

    Evolution of the uricotelic system for ammonia detoxification required a mechanism for tissue-specific subcellular localization of glutamine synthetase (GS). In uricotelic vertebrates, GS is mitochondrial in liver cells and cytoplasmic in brain. Because these species contain a single copy of the GS gene, it is not clear how tissue-specific subcellular localization is achieved. Here we show that in chicken, which utilizes the uricotelic system, the GS transcripts of liver and brain cells are identical and, consistently, there is no difference in the amino acid sequence of the protein. The N-terminus of GS, which constitutes a 'weak' mitochondrial targeting signal (MTS), is sufficient to direct a chimeric protein to the mitochondria in hepatocytes and to the cytoplasm in astrocytes. Considering that a weak MTS is dependent on a highly negative mitochondrial membrane potential (DeltaPsi) for import, we examined the magnitude of DeltaPsi in hepatocytes and astrocytes. Our results unexpectedly revealed that DeltaPsi in hepatocytes is considerably more negative than that of astrocytes and that converting the targeting signal into 'strong' MTS abolished the capability to confer tissue-specific subcellular localization. We suggest that evolutional selection of weak MTS provided a tool for differential targeting of an identical protein by taking advantage of tissue-specific differences in DeltaPsi. PMID:20053634

  10. Inhibition by propionyl-coenzyme A of N-acetylglutamate synthetase in rat liver mitochondria. A possible explanation for hyperammonemia in propionic and methylmalonic acidemia.

    PubMed

    Coude, F X; Sweetman, L; Nyhan, W L

    1979-12-01

    In the search for the mechanism by which hyperammonemia complicates propionic and methylmalonic acidemia the effects of a series of acyl-coenzyme A (CoA) derivatives were studied on the activity of N-acetylglutamate synthetase in rat liver mitochondria using acetyl-CoA as substrate. Propionyl-CoA was found to be a competitive inhibitor. The inhibition constant of 0.71 mM is in the range of concentrations of propionate found in the serum of patients with propionic and methylmalonic acidemia. Propionyl-CoA was also found to be a substrate for N-acetylglutamate synthetase, forming N-propionylglutamate. This compound was a weak activator of rat liver carbamoylphosphate synthetase; the activation constant was 1.1 mM as compared with 0.12 mM for N-acetylglutamate. A decreased level of N-acetylglutamate in liver mitochondria that would follow inhibition of N-acetylglutamate synthetase by propionyl-CoA would be expected to lead to hyperammonemia. Methylmalonyl-CoA, tiglyl-CoA, and isovaleryl-CoA at a concentration of 3 mM caused 30-70% inhibition of N-acetylglutamate synthetase. 3the latter two compounds are readily detoxified by the formation of N-acylglycine conjugates in liver, which may prevent large accumulations and could explain why hyperammonemia is not characteristic of patients with beta-ketothiolase deficiency or isovaleric acidemia in whom these compounds would be expected to be elevated. PMID:500823

  11. To involvement the conformation of the adenine nucleotide translocase in opening the Tl(+)-induced permeability transition pore in Ca(2+)-loaded rat liver mitochondria.

    PubMed

    Korotkov, Sergey M; Konovalova, Svetlana A; Brailovskaya, Irina V; Saris, Nils-Erik L

    2016-04-01

    The conformation of adenine nucleotide translocase (ANT) has a profound impact in opening the mitochondrial permeability transition pore (MPTP) in the inner membrane. Fixing the ANT in 'c' conformation by phenylarsine oxide (PAO), tert-butylhydroperoxide (tBHP), and carboxyatractyloside as well as the interaction of 4,4'-diisothiocyanostilbene-2,2'-disulfonate (DIDS) with mitochondrial thiols markedly attenuated the ability of ADP to inhibit the MPTP opening. We earlier found (Korotkov and Saris, 2011) that calcium load of rat liver mitochondria in medium containing TlNO3 and KNO3 stimulated the Tl(+)-induced MPTP opening in the inner mitochondrial membrane. The MPTP opening as well as followed increase in swelling, a drop in membrane potential (ΔΨmito), and a decrease in state 3, state 4, and 2,4-dinitrophenol-uncoupled respiration were visibly enhanced in the presence of PAO, tBHP, DIDS, and carboxyatractyloside. However, these effects were markedly inhibited by ADP and membrane-penetrant hydrophobic thiol reagent, N-ethylmaleimide (NEM) which fix the ANT in 'm' conformation. Cyclosporine A additionally potentiated these effects of ADP and NEM. Our data suggest that conformational changes of the ANT may be directly involved in the opening of the Tl(+)-induced MPTP in the inner membrane of Ca(2+)-loaded rat liver mitochondria. Using the Tl(+)-induced MPTP model is discussed in terms finding new transition pore inhibitors and inducers among different chemical and natural compounds. PMID:26835787

  12. Response of isolated rat liver mitochondria to variation of external osmolarity in KCl medium: regulation of matrix volume and oxidative phosphorylation.

    PubMed

    Devin, A; Guérin, B; Rigoulet, M

    1997-12-01

    When isolated rat liver mitochondria are incubated in KCI medium, matrix volume, flux, and forces in both hypo- and hyperosmolarity are time-dependent. In hypoosmotic KCl medium, matrix volume is regulated via the K+/H+ exchanger. In hyperosmotic medium, the volume is regulated in such a manner that at steady state, which is reached within 4 min, it is maintained whatever the hyperosmolarity. This regulation is Pi- and deltamuH+-dependent, indicating Pi-K salt entry into the matrix. Under steady state, hyperosmolarity has no effect on isolated rat liver mitochondria energetic parameters such as respiratory rate, proton electrochemical potential difference, and oxidative phosphorylation yield. Hypoosmolarity decreases the NADH/NAD+ ratio, state 3 respiratory rate, and deltamuH+, while oxidative phosphorylation yield is not significantly modified. This indicates kinetic control upstream the respiratory chain. This study points out the key role of potassium on the regulation of matrix volume, flux, and forces. Indeed, while matrix volume is regulated in NaCl hyperosmotic medium, flux and force restoration in hyperosmotic medium occurs only in the presence of external potassium. PMID:9559859

  13. Influence of aging and long-term caloric restriction on oxygen radical generation and oxidative DNA damage in rat liver mitochondria.

    PubMed

    López-Torres, Mónica; Gredilla, Ricardo; Sanz, Alberto; Barja, Gustavo

    2002-05-01

    The effect of long-term caloric restriction and aging on the rates of mitochondrial H2O2 production and oxygen consumption as well as on oxidative damage to nuclear (nDNA) and mitochondrial DNA (mtDNA) was studied in rat liver tissue. Long-term caloric restriction significantly decreased H2O2 production of rat liver mitochondria (47% reduction) and significantly reduced oxidative damage to mtDNA (46% reduction) with no changes in nDNA. The decrease in ROS production was located at complex I because it only took place with complex I-linked substrates (pyruvate/malate) but not with complex II-linked substrates (succinate). The mechanism responsible for that decrease in ROS production was not a decrease in mitochondrial oxygen consumption because it did not change after long-term restriction. Instead, the caloric restricted mitochondria released less ROS per unit electron flow, due to a decrease in the reduction degree of the complex I generator. On the other hand, increased ROS production with aging in state 3 was observed in succinate-supplemented mitochondria because old control animals were unable to suppress H2O2 production during the energy transition from state 4 to state 3. The levels of 8-oxodG in mtDNA increased with age in old animals and this increase was abolished by caloric restriction. These results support the idea that caloric restriction reduces the aging rate at least in part by decreasing the rate of mitochondrial ROS production and so, the rate of oxidative attack to biological macromolecules like mtDNA. PMID:11978489

  14. Increase in the ADP/ATP exchange in rat liver mitochondria irradiated in vitro by helium-neon laser

    SciTech Connect

    Passarella, S.; Ostuni, A.; Atlante, A.; Quagliariello, E.

    1988-10-31

    To gain some insight into the mechanism of cell photostimulation by laser light, measurements were made of the rate of ADP/ATP exchange in mitochondria irradiated with the low power continuous wave Helium Neon laser (energy dose 5 Joules/cm2). To do this a method has been developed to continuously monitor ATP efflux from phosphorylating mitochondria caused by externally added ADP, by photometrically following the NADP+ reduction which occurs in the presence of glucose, hexokinase, glucose-6-phosphate dehydrogenase and effluxed ATP. The NADP+ reduction rate shows hyperbolic dependence on ADP concentration (Km and Vmax values 8.5 +/- 0.87 microM and 20.7 +/- 0.49 nmoles NADP+ reduced/min x mg mitochondrial protein, respectively), and proves to measure the activity of the ADP/ATP translocator as shown by inhibition experiments using atracyloside, powerful inhibitor of this carrier. Irradiation was found to enhance the rate of ADP/ATP antiport, with externally added ADP ranging between 5 and 100 microM. As a result of experiments carried out with mitochondria loaded with either ATP or ADP, the increase in the activity of the ADP/ATP translocator is here proposed to depend on the increase in the electrochemical proton gradient which occurs owing to irradiation of mitochondria.

  15. Glutamate dehydrogenase in brain mitochondria: do lipid modifications and transient metabolon formation influence enzyme activity?

    PubMed Central

    McKenna, Mary C.

    2011-01-01

    Metabolism of glutamate, the primary excitatory neurotransmitter in brain, is complex and of paramount importance to overall brain function. Thus, understanding the regulation of enzymes involved in formation and disposal of glutamate and related metabolites is crucial to understanding glutamate metabolism. Glutamate dehydrogenase (GDH) is a pivotal enzyme that links amino acid metabolism and TCA cycle activity in brain and other tissues. The allosteric regulation of GDH has been extensively studied and characterized. Less is known about the influence of lipid modifications on GDH activity, and the participation of GDH in transient heteroenzyme complexes (metabolons) that can greatly influence metabolism by altering kinetic parameters and lead to channeling of metabolites. This review summarizes evidence for palmitoylation and acylation of GDH, information on protein binding, and information regarding the participation of GDH in transient heteroenzyme complexes. Recent studies suggest that a number of other proteins can bind to GDH altering activity and overall metabolism. It is likely that these modifications and interactions contribute additional levels of regulation of GDH activity and glutamate metabolism. PMID:21771624

  16. Protective effects of taurine in traumatic brain injury via mitochondria and cerebral blood flow.

    PubMed

    Wang, Qin; Fan, Weijia; Cai, Ying; Wu, Qiaoli; Mo, Lidong; Huang, Zhenwu; Huang, Huiling

    2016-09-01

    In mammalian tissues, taurine is an important natural component and the most abundant free amino acid in the heart, retina, skeletal muscle, brain, and leukocytes. This study is to examine the taurine's protective effects on neuronal ultrastructure, the function of the mitochondrial respiratory chain complex, and on cerebral blood flow (CBF). The model of traumatic brain injury (TBI) was made for SD rats by a fluid percussion device, with taurine (200 mg/kg) administered by tail intravenous injection once daily for 7 days after TBI. It was found that CBF was improved for both left and right brain at 30 min and 7 days post-injury by taurine. Reaction time was prolonged relative to the TBI-only group. Neuronal damage was prevented by 7 days taurine. Mitochondrial electron transport chain complexes I and II showed greater activity with the taurine group. The improvement by taurine of CBF may alleviate edema and elevation in intracranial pressure. Importantly taurine improved the hypercoagulable state. PMID:27156064

  17. Novel function of glutathione transferase in rat liver mitochondrial membrane: Role for cytochrome c release from mitochondria

    SciTech Connect

    Lee, Kang Kwang; Shimoji, Manami; Hossain, Quazi Sohel; Sunakawa, Hajime; Aniya, Yoko

    2008-10-01

    Microsomal glutathione transferase (MGST1) is activated by oxidative stress. Although MGST1 is found in mitochondrial membranes (mtMGST1), there is no information about the oxidative activation of mtMGST1. In the present study, we aimed to determine whether mtMGST1 also undergoes activation and about its function. When rats were treated with galactosamine/lipopolysaccharide (GalN/LPS), mtMGST1 activity was significantly increased, and the increased activity was reduced by the disulfide reducing agent dithiothreitol. In mitochondria from GalN/LPS-treated rats, disulfide-linked mtMGST1 dimer and mixed protein glutathione disulfides (glutathionylation) were detected. In addition, cytochrome c release from mitochondria isolated from GalN/LPS-treated rats was observed, and the release was inhibited by anti-MGST1 antibodies. Incubation of mitochondria from control rats with diamide and diamide plus GSH in vitro resulted in dimer- and mixed disulfide bond-mediated activation of mtMGST1, respectively. The activation of mtMGST1 by diamide plus GSH caused cytochrome c release from the mitochondria, and the release was prevented by treatment with anti-MGST1 antibodies. In addition, diamide plus GSH treatment caused mitochondrial swelling accompanied by cytochrome c release, which was inhibited by cyclosporin A (CsA) and bongkrekic acid (BKA), inhibitors of the mitochondrial permeability transition (MPT) pore. Furthermore, mtMGST1 activity was also inhibited by CsA and BKA. These results indicate that mtMGST1 is activated through mixed disulfide bond formation that contributes to cytochrome c release from mitochondria through the MPT pore.

  18. Data supporting the involvement of the adenine nucleotide translocase conformation in opening the Tl+-induced permeability transition pore in Ca2+-loaded rat liver mitochondria

    PubMed Central

    Korotkov, Sergey M.

    2016-01-01

    There we made available information about the effects of the adenine nucleotide translocase (ANT) ‘c’ conformation fixers (phenylarsine oxide (PAO), tert-butylhydroperoxide (tBHP), and carboxyatractyloside) as well as thiol reagent (4,4′-diisothiocyanostilbene-2,2′-disulfonate (DIDS)) on isolated rat liver mitochondria. We observed a decrease in A540 (mitochondrial swelling) and respiratory control rates (RCRADP [state 3/state 4] and RCRDNP [2,4-dinitrophenol-uncoupled state/basal state or state 4]), as well as an increase in Ca2+-induced safranin fluorescence (F485/590, arbitrary units), showed a dissipation in the inner membrane potential (ΔΨmito), in experiments with energized rat liver mitochondria, injected into the buffer containing 25–75 mM TlNO3, 125 mM KNO3, and 100 µM Ca2+. The fixers and DIDS, in comparison to Ca2+ alone, greatly increased A540 decline and the rate of Ca2+-induced ΔΨmito dissipation. These reagents also markedly decreased RCRADP and RCRDNP. The MPTP inhibitors (ADP, cyclosporin A, bongkrekic acid, and N-ethylmaleimide) fixing the ANT in ‘m’ conformation significantly hindered the above-mentioned effects of the fixers and DIDS. A more complete scientific analysis of these findings may be obtained from the manuscript “To involvement the conformation of the adenine nucleotide translocase in opening the Tl+-induced permeability transition pore in Ca2+-loaded rat liver mitochondria” (Korotkov et al., 2016 [1]). PMID:27054168

  19. A Fast Method for the Segmentation of Synaptic Junctions and Mitochondria in Serial Electron Microscopic Images of the Brain.

    PubMed

    Márquez Neila, Pablo; Baumela, Luis; González-Soriano, Juncal; Rodríguez, Jose-Rodrigo; DeFelipe, Javier; Merchán-Pérez, Ángel

    2016-04-01

    Recent electron microscopy (EM) imaging techniques permit the automatic acquisition of a large number of serial sections from brain samples. Manual segmentation of these images is tedious, time-consuming and requires a high degree of user expertise. Therefore, there is considerable interest in developing automatic segmentation methods. However, currently available methods are computationally demanding in terms of computer time and memory usage, and to work properly many of them require image stacks to be isotropic, that is, voxels must have the same size in the X, Y and Z axes. We present a method that works with anisotropic voxels and that is computationally efficient allowing the segmentation of large image stacks. Our approach involves anisotropy-aware regularization via conditional random field inference and surface smoothing techniques to improve the segmentation and visualization. We have focused on the segmentation of mitochondria and synaptic junctions in EM stacks from the cerebral cortex, and have compared the results to those obtained by other methods. Our method is faster than other methods with similar segmentation results. Our image regularization procedure introduces high-level knowledge about the structure of labels. We have also reduced memory requirements with the introduction of energy optimization in overlapping partitions, which permits the regularization of very large image stacks. Finally, the surface smoothing step improves the appearance of three-dimensional renderings of the segmented volumes. PMID:26780198

  20. Atherosclerotic lesions and mitochondria DNA deletions in brain microvessels: Implication in the pathogenesis of Alzheimer’s disease

    PubMed Central

    Aliev, Gjumrakch; Gasimov, Eldar; Obrenovich, Mark E; Fischbach, Kathryn; Shenk, Justin C; Smith, Mark A; Perry, George

    2008-01-01

    The pathogenesis that is primarily responsible for Alzheimer’s disease (AD) and cerebrovascular accidents (CVA) appears to involve chronic hypoperfusion. We studied the ultrastructural features of vascular lesions and mitochondria in brain vascular wall cells from human AD biopsy samples and two transgenic mouse models of AD, yeast artificial chromosome (YAC) and C57B6/SJL Tg (+), which overexpress human amyloid beta precursor protein (AβPP). In situ hybridization using probes for normal and 5 kb deleted human and mouse mitochondrial DNA (mtDNA) was performed along with immunocytochemistry using antibodies against the Aβ peptide processed from AβPP, 8-hydroxy-2’-guanosine (8OHG), and cytochrome c oxidase (COX). More amyloid deposition, oxidative stress markers as well as mitochondrial DNA deletions and structural abnormalities were present in the vascular walls of the human AD samples and the AβPP-YAC and C57B6/SJL Tg (+) transgenic mice compared to age-matched controls. Ultrastructural damage in perivascular cells highly correlated with endothelial lesions in all samples. Therefore, pharmacological interventions, directed at correcting the chronic hypoperfusion state, may change the natural course of the development of dementing neurodegeneration. PMID:18827923

  1. Study of the Effects of ATP Suppliers and Thiol Reductants on Toxicity of Pioglitazone in Isolated Rat Liver Mitochondria

    PubMed Central

    Rezaiean Mehrabadi, Abbas; Jamshidzadeh, Akram; Rashedinia, Marzieh; Niknahad, Hossein

    2015-01-01

    Pioglitazone (PG) is one of thiazolidinediones used for the treatment of type II diabetes mellitus. Some reports of its hepatotoxicity exist, but the mechanism of its hepatotoxicity is not well known. In the present study, the protective effect of some ATP suppliers are investigated against mitochondrial toxicity of PG in isolated rat mitochondria. Mitochondrial viability was investigated by MTT assay. The effects of PG on superoxide dismutase activity, ATP production, mitochondrial swelling and oxidative stress were also investigated. PG reduced mitochondrial viability with an LC50 of 880±32 µM. It reduced ATP production and superoxide dismutase activity in mitochondria and increased mitochondrial swelling, but no oxidant effect was present as measured by TBARS formation. Fructose, dihydroxyacetone, dithioteritol, and N-acetylcysteine reduced mitochondrial toxicity of PG. Therefore, PG toxicity may be due to its mitochondrial toxicity and energy depletion, and ATP suppliers could be effective in preventing its toxicity. PMID:26330870

  2. The Liver-Brain Axis of Alcohol-Mediated Neurodegeneration: Role of Toxic Lipids

    PubMed Central

    de la Monte, Suzanne M.; Longato, Lisa; Tong, Ming; DeNucci, Sarah; Wands, Jack R.

    2009-01-01

    Alcohol abuse causes progressive toxicity and degeneration in liver and brain due to insulin resistance, which exacerbates oxidative stress and pro-inflammatory cytokine activation. Alcohol-induced steatohepatitis promotes synthesis and accumulation of ceramides and other toxic lipids that cause insulin resistance. Ceramides can readily cross the blood-brain barrier, and ceramide exposure causes neurodegeneration with insulin resistance and oxidative stress, similar to the effects of alcohol. Therefore, in addition to its direct neurotoxic effects, alcohol misuse establishes a liver-brain axis of neurodegeneration mediated by toxic lipid trafficking across the blood-brain barrier, leading to progressive white matter degeneration and cognitive impairment. PMID:19742171

  3. Kinetics of P/sub i/-P/sub i/ exchange in rat liver mitochondria. Rapid filtration experiments in the millisecond time range

    SciTech Connect

    Ligeti, E.; Brandolin, G.; Dupont, Y.; Vignais, P.V.

    1985-07-30

    Phosphate-phosphate exchange through the inorganic phosphate (P/sub i/) carrier of rat liver mitochondria was investigated by a new rapid filtration technique, which does not require the use of transport inhibitors to stop the reaction and offers high time resolution (starting from 10 ms), thus allowing kinetic measurements on a fine time scale even at room temperature. At approximately 22 degrees C, isotopic equilibrium of (TSP)P/sub i/ is achieved within 0.8-2.5 s--depending on the P/sub i/ concentration--and an initial linear phase, lasting for 400-500 ms, is observed. Complete inhibition of P/sub i/ exchange by an excess of mersalyl, a well-known organomercurial inhibitor, required 200 ms, pointing to the insufficiency of this reagent for effective inhibitor stop. On the other hand, investigation of the effect of mersalyl on the initial rate of P/sub i/ exchange supports earlier observations on the protective effect of this inhibitor. In nonrespiring mitochondria, at pH 7.3, P/sub i/ exchange exhibited a K/sub m/ of 1.6 mM and a V/sub max/ of 3.0 mumol min-1 (mg of mitochondrial protein)-1. The maximal velocity of P/sub i/ transport is significantly higher than the maximal velocity of all the other components of oxidative phosphorylation at comparable temperatures. The possible physiological significance of this excess capacity is discussed.

  4. Biological effects of anionic meso-tetrakis (para-sulfonatophenyl) porphyrins modulated by the metal center. Studies in rat liver mitochondria.

    PubMed

    Pessoto, Felipe Samuel; Inada, Natalia Mayumi; Nepomuceno, Maria de Fátima; Ruggiero, Ana Célia; Nascimento, Otaciro R; Vercesi, Anibal E; Nantes, Iseli L

    2009-10-30

    In this paper, we present a study about the influence of the porphyrin metal center and meso ligands on the biological effects of meso-tetrakis porphyrins. Different from the cationic meso-tetrakis 4-N-methyl pyridinium (Mn(III)TMPyP), the anionic Mn(III) meso-tetrakis (para-sulfonatophenyl) porphyrin (Mn(III)TPPS4) exhibited no protector effect against Fe(citrate)-induced lipid oxidation. Mn(III)TPPS4 did not protect mitochondria against endogenous hydrogen peroxide and only delayed the swelling caused by tert-BuOOH and Ca2+. Fe(III)TPPS4 exacerbated the effect of the tert-BuOOH, and both porphyrins did not significantly affect Fe(II)citrate-induced swelling. Consistently, Fe(III)TPPS4 predominantly promotes the homolytic cleavage of peroxides and exhibits catalytic efficiency ten-fold higher than Mn(III)TPPS4. For Mn(III)TPPS4, the microenvironment of rat liver mitochondria favors the heterolytic cleavage of peroxides and increases the catalytic efficiency of the manganese porphyrin due to the availability of axial ligands for the metal center and reducing agents such as glutathione (GSH) and proteins necessary for Compound II (oxomanganese IV) recycling to the initial Mn(III) form. The use of thiol reducing agents for the recycling of Mn(III)TPPS4 leads to GSH depletion and protein oxidation and consequent damages in the organelle. PMID:19631199

  5. Sex-specific divergence of antioxidant pathways in fetal brain, liver, and skeletal muscles.

    PubMed

    Al-Gubory, Kaïs H; Garrel, Catherine

    2016-01-01

    The sex-specific divergence of antioxidant pathways in fetal organs of opposite-sex twin is unknown and remains urgently in need of investigation. Such study faces many challenges, mainly the ethical impossibility of obtaining human fetal organs. Opposite-sex sheep twins represent a unique model for studying a sex dimorphism for antioxidant systems. The activity of total superoxide dismutase (SOD), SOD1, SOD2, glutathione peroxidase (GPX), glutathione reductase (GR) and catalase (CAT), the content of total glutathione, reduced glutathione (GSH), and oxidized glutathione (GSSG) were measured in brain, lung, liver, kidney, and skeletal muscles of female and male fetuses collected from sheep twin pregnancies at day 65 of gestation. Lipid peroxidation was assessed by measuring melondialdehyde (MDA) tissue content. Male brain has greater total SOD and SOD1 activities than female brain. Female liver has greater SOD2 activity than male liver. Male liver has greater GR activity than female liver. Male liver has higher total GSH and GSSG content than female liver. Male skeletal muscles have higher total GSH, GSH, and GSSG content than female skeletal muscles. Female brain and liver have higher MDA content than male brain and liver. This is the first report of a sex dimorphism for fetal organ antioxidative pathways. Brain, liver, and skeletal muscles of male and female fetuses display distinct antioxidant pathways. Such sexually dimorphic responses to early life oxidative stress might be involved in the sex-related difference in fetal development that may have a long-term effect on offspring. Our study urges researchers to take into consideration the importance of sex as a biologic variable in their investigations. PMID:26765668

  6. Products and intermediates of the beta-oxidation of [U-14C]hexadecanedionoyl-mono-CoA by rat liver peroxisomes and mitochondria.

    PubMed Central

    Pourfarzam, M; Bartlett, K

    1991-01-01

    1. The synthesis of [U-14C]hexadecanedionoyl-mono-CoA is described. 2. The beta-oxidation of [U-14C]hexadecanedionoyl-mono-CoA by purified rat liver peroxisomes and mitochondria is demonstrated. 3. The products of mitochondrial beta-oxidation of [U-14C]hexadecanedionoyl-mono-CoA include ketone bodies, citrate and acetylcarnitine. 4. Tetradecadionoyl-mono-CoA, hexadec-2-enedionyl-mono-CoA and hexadionoyl-mono-CoA were the only detectable intermediates formed by mitochondrial beta-oxidation, whereas acetyl-CoA and all saturated even-numbered intermediates of chain length C6-C16 were generated by peroxisomal beta-oxidation. 5. Hexadecanedionoyl-mono-CoA and hexadecanoyl-CoA were equally effective substrates for peroxisomal beta-oxidation, but hexadecanedionoyl-mono-CoA was a relatively poorer substrate for the mitochondrial pathway. PMID:1989582

  7. Effects of thyroid hormones on the bypasses of the antimycin A block in the bc1 complex of rat liver mitochondria.

    PubMed

    Horrum, M A; Tobin, R B; Ecklund, R E

    1991-07-15

    The effect of thyroid hormones on the electron flow through the bc1 complex of rat liver mitochondria was studied using two dye bypasses of the Antimycin A block of the bc1 complex by the method of Alexandre and Lehninger (Biochim. Biophys. Acta 767:120; 1984). Bypass respiration rates with both DCIP (2,6-dichlorophenolindophenol) and TMPD (N,N,N',N'-tetramethyl-p-phenylenediamine dihydrochloride) were elevated in the hyperthyroid rats and depressed in the hypothyroid groups compared to the euthyroid controls. T3 treatment of hypothyroid rats returned the bypass rates to control levels in 24 hours with the TMPD dye but not for the DCIP. This further demonstrates that different portions of the bc1 complex respond individually to the thyroid state. PMID:1648915

  8. Steady-state concentrations of coenzyme A, acetyl-coenzyme A and long-chain fatty acyl-coenzyme A in rat-liver mitochondria oxidizing palmitate

    PubMed Central

    Garland, P. B.; Shepherd, D.; Yates, D. W.

    1965-01-01

    1. Fluorimetric assays are described for CoASH, acetyl-CoA and long-chain fatty acyl-CoA, and are sensitive to at least 50μμmoles of each. 2. Application of these assays to rat-liver mitochondria oxidizing palmitate in the absence and presence of carnitine indicated two pools of intramitochondrial CoA. One pool could be acylated by palmitate and ATP, and the other pool acylated by palmitate with ATP and carnitine, or by palmitoylcarnitine alone. 3. The intramitochondrial content of acetyl-CoA is increased by the oxidation of palmitate both in the absence and presence of l-malate. 4. The conversion of palmitoyl-CoA into acetyl-CoA by β-oxidation takes place without detectable accumulation of acyl-CoA intermediates. PMID:16749169

  9. Safety evaluation of mercury based Ayurvedic formulation (Sidh Makardhwaj) on brain cerebrum, liver & kidney in rats

    PubMed Central

    Kumar, Gajendra; Srivastava, Amita; Sharma, Surinder Kumar; Gupta, Yogendra Kumar

    2014-01-01

    Background & objectives: Sidh Makardhwaj (SM) is a mercury based Ayurvedic formulation used in rheumatoid arthritis and neurological disorders. However, toxicity concerns due to mercury content are often raised. Therefore, the present study was carried out to evaluate the effect of SM on brain cerebrum, liver and kidney in rats. Methods: Graded doses of SM (10, 50, 100 mg/kg), mercuric chloride (1 mg/kg) and normal saline were administered orally to male Wistar rats for 28 days. Behavioural parameters were assessed on days 1, 7, 14 and 28 using Morris water maze, passive avoidance, elevated plus maze and rota rod. Liver and kidney function tests were done on day 28. Animals were sacrificed and brain cerebrum acetylcholinesterase activity, levels of malondialdehyde (MDA), reduced glutathione (GSH) in brain cerebrum, liver, kidney were estimated. The levels of mercury in brain cerebrum, liver and kidney were estimated and histopathology of these tissues was also performed. Results: SM in the doses used did not cause significant change in neurobehavioural parameters, brain cerebrum AChE activity, liver (ALT, AST, ALP bilirubin) and kidney (serum urea and creatinine) function tests as compared to control. The levels of mercury in brain cerebrum, liver, and kidney were found to be raised in dose dependent manner. However, the levels of MDA and GSH in these tissues did not show significant changes at doses of 10 and 50 mg/kg. Also, there was no histopathological change in cytoarchitecture of brain cerebrum, liver, and kidney tissues at doses of 10 and 50 mg/kg. Interpretation & conclusions: The findings of the present study suggest that Sidh Makardhwaj upto five times the equivalent human dose administered for 28 days did not show any toxicological effects on rat brain cerebrum, liver and kidney. PMID:24927349

  10. Differential metabolism of 4-hydroxynonenal in liver, lung and brain of mice and rats

    SciTech Connect

    Zheng, Ruijin; Dragomir, Ana-Cristina; Mishin, Vladimir; Richardson, Jason R.; Heck, Diane E.; Laskin, Debra L.; Laskin, Jeffrey D.

    2014-08-15

    The lipid peroxidation end-product 4-hydroxynonenal (4-HNE) is generated in tissues during oxidative stress. As a reactive aldehyde, it forms Michael adducts with nucleophiles, a process that disrupts cellular functioning. Liver, lung and brain are highly sensitive to xenobiotic-induced oxidative stress and readily generate 4-HNE. In the present studies, we compared 4-HNE metabolism in these tissues, a process that protects against tissue injury. 4-HNE was degraded slowly in total homogenates and S9 fractions of mouse liver, lung and brain. In liver, but not lung or brain, NAD(P)+ and NAD(P)H markedly stimulated 4-HNE metabolism. Similar results were observed in rat S9 fractions from these tissues. In liver, lung and brain S9 fractions, 4-HNE formed protein adducts. When NADH was used to stimulate 4-HNE metabolism, the formation of protein adducts was suppressed in liver, but not lung or brain. In both mouse and rat tissues, 4-HNE was also metabolized by glutathione S-transferases. The greatest activity was noted in livers of mice and in lungs of rats; relatively low glutathione S-transferase activity was detected in brain. In mouse hepatocytes, 4-HNE was rapidly taken up and metabolized. Simultaneously, 4-HNE-protein adducts were formed, suggesting that 4-HNE metabolism in intact cells does not prevent protein modifications. These data demonstrate that, in contrast to liver, lung and brain have a limited capacity to metabolize 4-HNE. The persistence of 4-HNE in these tissues may increase the likelihood of tissue injury during oxidative stress. - Highlights: • Lipid peroxidation generates 4-hydroxynonenal, a highly reactive aldehyde. • Rodent liver, but not lung or brain, is efficient in degrading 4-hydroxynonenal. • 4-hydroxynonenal persists in tissues with low metabolism, causing tissue damage.

  11. Discovery and confirmation of O-GlcNAcylated proteins in rat liver mitochondria by combination of mass spectrometry and immunological methods.

    PubMed

    Cao, Weiqian; Cao, Jing; Huang, Jiangming; Yao, Jun; Yan, Guoquan; Xu, Haoqi; Yang, Pengyuan

    2013-01-01

    O-linked β-N-acetylglucosamine (O-GlcNAc) is an important post-translational modification (PTM) consisting of a single N-acetylglucosamine moiety attached via an O-β-glycosidic linkage to serine and threonine residues. Glycosylation with O-GlcNAc occurs on myriad nuclear and cytosolic proteins from almost all functional classes. However, with respect to O-GlcNAcylated proteins special in mitochondria, little attention has been paid. In this study, we combined mass spectrometry and immunological methods to perform global exploration of O-GlcNAcylated proteins specific in mitochondria of rat liver. First, highly purified mitochondrial proteins were obviously shown to be O-GlcNAcylated by immunoblot profiling. Then, β-elimination followed by Michael Addition with Dithiothreitol (BEMAD) treatment and LC-MS/MS were performed to enrich and identify O-GlcNAcylated mitochondrial proteins, resulting in an unambiguous assignment of 14 O-GlcNAcylation sites, mapping to 11 O-GlcNAcylated proteins. Furthermore, the identified O-GlcNAcylated mitochondrial proteins were fully validated by both electron transfer dissociation tandem mass spectrometry (ETD/MS/MS) and western blot. Thus, for the first time, our study definitely not only identified but also validated that some mitochondrial proteins in rat liver are O-GlcNAcylated. Interestingly, all of these O-GlcNAcylated mitochondrial proteins are enzymes, the majority of which are involved in a wide variety of biological processes, such as urea cycle, tricarboxylic acid cycle and lipid metabolism, indicating a role for protein O-GlcNAcylation in mitochondrial function. PMID:24098488

  12. Liver transplant outcomes using ideal donation after circulatory death livers are superior to using older donation after brain death donor livers.

    PubMed

    Scalea, Joseph R; Redfield, Robert R; Foley, David P

    2016-09-01

    Multiple reports have demonstrated that liver transplantation following donation after circulatory death (DCD) is associated with poorer outcomes when compared with liver transplantation from donation after brain death (DBD) donors. We hypothesized that carefully selected, underutilized DCD livers recovered from younger donors have excellent outcomes. We performed a retrospective study of the United Network for Organ Sharing database to determine graft survivals for patients who received liver transplants from DBD donors of age ≥ 60 years, DBD donors < 60 years, and DCD donors < 50 years of age. Between January 2002 and December 2014, 52,271 liver transplants were performed in the United States. Of these, 41,181 (78.8%) underwent transplantation with livers from DBD donors of age < 60 years, 8905 (17.0%) from DBD donors ≥ 60 years old, and 2195 (4.2%) livers from DCD donors < 50 years of age. DCD livers of age < 50 years with < 6 hours of cold ischemia time (CIT) had superior graft survival when compared with DBD livers ≥ age 60 years (P < 0.001). In 2014, there were 133 discarded DCD livers; of these, 111 (83.4%) were from donors < age 50 years old. Young DCD donor livers (age < 50 years old) with short CITs yield results better than that seen with DBD livers > 60 years old. Careful donor organ and recipient selection can lead to excellent results, despite previous reports suggesting otherwise. Increased acceptance of these DCD livers would lead to shorter wait list times and increased national liver transplant rates. Liver Transplantation 22 1197-1204 2016 AASLD. PMID:27314220

  13. Toxicity of cuprizone a Cu(2+) chelating agent on isolated mouse brain mitochondria: a justification for demyelination and subsequent behavioral dysfunction.

    PubMed

    Faizi, Mehrdad; Salimi, Ahmad; Seydi, Enayatolla; Naserzadeh, Parvaneh; Kouhnavard, Mehdi; Rahimi, Atena; Pourahmad, Jalal

    2016-05-01

    Multiple Sclerosis (MS) is a complex disease with an unknown etiology and no effective cure, despite decades of extensive research that led to the development of several partially effective treatments. In this study we aimed to investigate brain mitochondrial dysfunction in demyelination induced by cuprizone in mice. Cuprizone was used for induction of demyelination in mice through a diet containing 0.2% w/w cuprizone for 5 weeks. Behavioral tests for proving of MS was performed and then mitochondria from brain of animals were isolated and afterwards parameters of mitochondrial dysfunction examined. Results of mitochondrial dysfunction parameters such as mitochondrial swelling, production ROS, collapse of the membrane potential showed that isolated mitochondria from cuprizone treated mice have been damaged compared to those of untreated control mice. It is likely that demyelination induced mitochondrial damage led to increased mitochondrial ROS formation and progression of oxidative damages in neurons. It is suggested that cuprizone which is a Cu(2+) chelating agent causes impairment of electron transport chain (complex IV) and antioxidant system (SOD) in mitochondria leading to decreased ATP production and increased ROS formation. PMID:27088566

  14. Knockout of cyclophilin D in Ppif⁻/⁻ mice increases stability of brain mitochondria against Ca²⁺ stress.

    PubMed

    Gainutdinov, T; Molkentin, J D; Siemen, D; Ziemer, M; Debska-Vielhaber, G; Vielhaber, S; Gizatullina, Z; Orynbayeva, Z; Gellerich, F N

    2015-08-01

    The mitochondrial peptidyl prolyl isomerase cyclophilin D (CypD) activates permeability transition (PT). To study the role of CypD in this process we compared the functions of brain mitochondria isolated from wild type (BMWT) and CypD knockout (Ppif(-/-)) mice (BMKO) with and without CypD inhibitor Cyclosporin A (CsA) under normal and Ca(2+) stress conditions. Our data demonstrate that BMKO are characterized by higher rates of glutamate/malate-dependent oxidative phosphorylation, higher membrane potential and higher resistance to detrimental Ca(2+) effects than BMWT. Under the elevated Ca(2+) and correspondingly decreased membrane potential the dose response in BMKO shifts to higher Ca(2+) concentrations as compared to BMWT. However, significantly high Ca(2+) levels result in complete loss of membrane potential in BMKO, too. CsA diminishes the loss of membrane potential in BMWT but has no protecting effect in BMKO. The results are in line with the assumption that PT is regulated by CypD under the control of matrix Ca(2+). Due to missing of CypD the BMKO can favor PT only at high Ca(2+) concentrations. It is concluded that CypD sensitizes the brain mitochondria to PT, and its inhibition by CsA or CypD absence improves the complex I-related mitochondrial function and increases mitochondria stability against Ca(2+) stress. PMID:26032335

  15. Protective effects of dietary avocado oil on impaired electron transport chain function and exacerbated oxidative stress in liver mitochondria from diabetic rats.

    PubMed

    Ortiz-Avila, Omar; Gallegos-Corona, Marco Alonso; Sánchez-Briones, Luis Alberto; Calderón-Cortés, Elizabeth; Montoya-Pérez, Rocío; Rodriguez-Orozco, Alain R; Campos-García, Jesús; Saavedra-Molina, Alfredo; Mejía-Zepeda, Ricardo; Cortés-Rojo, Christian

    2015-08-01

    Electron transport chain (ETC) dysfunction, excessive ROS generation and lipid peroxidation are hallmarks of mitochondrial injury in the diabetic liver, with these alterations also playing a role in the development of non-alcoholic fatty liver disease (NAFLD). Enhanced mitochondrial sensitivity to lipid peroxidation during diabetes has been also associated to augmented content of C22:6 in membrane phospholipids. Thus, we aimed to test whether avocado oil, a rich source of C18:1 and antioxidants, attenuates the deleterious effects of diabetes on oxidative status of liver mitochondria by decreasing unsaturation of acyl chains of membrane lipids and/or by improving ETC functionality and decreasing ROS generation. Streptozocin-induced diabetes elicited a noticeable increase in the content of C22:6, leading to augmented mitochondrial peroxidizability index and higher levels of lipid peroxidation. Mitochondrial respiration and complex I activity were impaired in diabetic rats with a concomitant increase in ROS generation using a complex I substrate. This was associated to a more oxidized state of glutathione, All these alterations were prevented by avocado oil except by the changes in mitochondrial fatty acid composition. Avocado oil did not prevented hyperglycemia and polyphagia although did normalized hyperlipidemia. Neither diabetes nor avocado oil induced steatosis. These results suggest that avocado oil improves mitochondrial ETC function by attenuating the deleterious effects of oxidative stress in the liver of diabetic rats independently of a hypoglycemic effect or by modifying the fatty acid composition of mitochondrial membranes. These findings might have also significant implications in the progression of NAFLD in experimental models of steatosis. PMID:26060181

  16. Rhein Elicits In Vitro Cytotoxicity in Primary Human Liver HL-7702 Cells by Inducing Apoptosis through Mitochondria-Mediated Pathway

    PubMed Central

    Bounda, Guy-Armel; Zhou, Wang; Wang, Dan-dan; Yu, Feng

    2015-01-01

    Objective. To study rhein-induced apoptosis signaling pathway and to investigate its molecular mechanisms in primary human hepatic cells. Results. Cell viability of HL-7702 cells treated with rhein showed significant decrease in dose-dependent manner. Following rhein treatment (25 μM, 50 μM, and 100 μM) for 12 h, the detection of apoptotic cells was significantly analyzed by flow cytometry and nuclear morphological changes by Hoechst 33258, respectively. Fatty degeneration studies showed upregulation level of the relevant hepatic markers (P < 0.01). Caspase activities expressed significant upregulation of caspase-3, caspase-9, and caspase-8. Moreover, apoptotic cells by rhein were significantly inhibited by Z-LEHD-FMK and Z-DEVD-FMK, caspase-9 inhibitor, and caspase-3 inhibitor, respectively. Overproduction of reactive oxygen species, lipid peroxidation, and loss of mitochondrial membrane potential were detected by fluorometry. Additionally, NAC, a ROS scavenger, significantly attenuated rhein-induced oxidative damage in HL-7702 cells. Furthermore, real-time qPCR results showed significant upregulation of p53, PUMA, Apaf-1, and Casp-9 and Casp-3 mRNA, with no significant changes of Fas and Cytochrome-c. Immunoblotting revealed significant Cytochrome-c release from mitochondria into cytosol and no change in Fas expression. Conclusion. Taken together, these observations suggested that rhein could induce apoptosis in HL-7702 cells via mitochondria-mediated signal pathway with involvement of oxidative stress mechanism. PMID:26221172

  17. Liver irradiation causes distal bystander effects in the rat brain and affects animal behaviour

    PubMed Central

    Kovalchuk, Anna; Mychasiuk, Richelle; Muhammad, Arif; Hossain, Shakhawat; Ilnytskyy, Slava; Ghose, Abhijit; Kirkby, Charles; Ghasroddashti, Esmaeel; Kovalchuk, Olga; Kolb, Bryan

    2016-01-01

    Radiation therapy can not only produce effects on targeted organs, but can also influence shielded bystander organs, such as the brain in targeted liver irradiation. The brain is sensitive to radiation exposure, and irradiation causes significant neuro-cognitive deficits, including deficits in attention, concentration, memory, and executive and visuospatial functions. The mechanisms of their occurrence are not understood, although they may be related to the bystander effects. We analyzed the induction, mechanisms, and behavioural repercussions of bystander effects in the brain upon liver irradiation in a well-established rat model. Here, we show for the first time that bystander effects occur in the prefrontal cortex and hippocampus regions upon liver irradiation, where they manifest as altered gene expression and somewhat increased levels of γH2AX. We also report that bystander effects in the brain are associated with neuroanatomical and behavioural changes, and are more pronounced in females than in males. PMID:26678032

  18. Exendin-4 attenuates brain death-induced liver damage in the rat.

    PubMed

    Carlessi, Rodrigo; Lemos, Natalia E; Dias, Ana L; Brondani, Leticia A; Oliveira, Jarbas R; Bauer, Andrea C; Leitão, Cristiane B; Crispim, Daisy

    2015-11-01

    The majority of liver grafts destined for transplantation originate from brain dead donors. However, significantly better posttransplantation outcomes are achieved when organs from living donors are used, suggesting that brain death (BD) causes irreversible damage to the liver tissue. Recently, glucagon-like peptide-1 (GLP1) analogues were shown to possess interesting hepatic protection effects in different liver disease models. We hypothesized that donor treatment with the GLP1 analogue exendin-4 (Ex-4) could alleviate BD-induced liver damage. A rat model of BD was employed in order to estimate BD-induced liver damage and Ex-4's potential protective effects. Liver damage was assessed by biochemical determination of circulating hepatic markers. Apoptosis in the hepatic tissue was assessed by immunoblot and immunohistochemistry using an antibody that only recognizes the active form of caspase-3. Gene expression changes in inflammation and stress response genes were monitored by quantitative real-time polymerase chain reaction. Here, we show that Ex-4 administration to the brain dead liver donors significantly reduces levels of circulating aspartate aminotransferase and lactate dehydrogenase. This was accompanied by a remarkable reduction in hepatocyte apoptosis. In this model, BD caused up-regulation of tumor necrosis factor and stress-related genes, confirming previous findings in clinical and animal studies. In conclusion, treatment of brain dead rats with Ex-4 reduced BD-induced liver damage. Further investigation is needed to determine the molecular basis of the observed liver protection. After testing in a randomized clinical trial, the inclusion of GLP1 analogues in organ donor management might help to improve organ quality, maximize organ donation, and possibly increase liver transplantation success rates. PMID:26334443

  19. The abolishment of anesthesia-induced cognitive impairment by timely protection of mitochondria in the developing rat brain: the importance of free oxygen radicals and mitochondrial integrity

    PubMed Central

    Boscolo, A; Starr, JA; Sanchez; Lunardi, N; DiGruccio, MR; Ori, C; Erisir, A; Trimmer, P; Bennett, J; Jevtovic-Todorovic

    2011-01-01

    Early exposure to general anesthesia (GA) causes developmental neuroapoptosis in the mammalian brain and long-term cognitive impairment. Recent evidence suggests that GA also causes functional and morphological impairment of the immature neuronal mitochondria. Injured mitochondria could be a significant source of reactive oxygen species (ROS), which, if not scavenged in timely fashion, may cause excessive lipid peroxidation and damage of cellular membranes. We examined whether early exposure to GA results in ROS upregulation and whether mitochondrial protection and ROS scavenging prevent GA-induced pathomorphological and behavioral impairments. We exposed 7-day-old rats to GA with or without either EUK-134, a synthetic ROS scavenger, or R(+) pramipexole (PPX), a synthetic aminobenzothiazol derivative that restores mitochondrial integrity. We found that GA causes extensive ROS upregulation and lipid peroxidation, as well as mitochondrial injury and neuronal loss in the subiculum. As compared to rats given only GA, those also given PPX or EUK-134 had significantly downregulated lipid peroxidation, preserved mitochondrial integrity, and significantly less neuronal loss. The subiculum is highly intertwined with the hippocampal CA1 region, anterior thalamic nuclei, and both entorhinal and cingulate cortices; hence, it is important in cognitive development. We found that PPX or EUK-134 co-treatment completely prevented GA-induced cognitive impairment. Because mitochondria are vulnerable to GA-induced developmental neurotoxicity, they could be an important therapeutic target for adjuvant therapy aimed at improving the safety of commonly used GAs. PMID:22198380

  20. In vitro effects of cholesterol β-D-glucoside, cholesterol and cycad phytosterol glucosides on respiration and reactive oxygen species generation in brain mitochondria.

    PubMed

    Panov, Alexander; Kubalik, Nataliya; Brooks, Benjamin R; Shaw, Christopher A

    2010-10-01

    The cluster of neurodegenerative disorders in the western Pacific termed amyotrophic lateral sclerosis-parkinsonism dementia complex (ALS-PDC) has been repeatedly linked to the use of seeds of various species of cycad. Identification and chemical synthesis of the most toxic compounds in the washed cycad seeds, a variant phytosteryl glucosides, and even more toxic cholesterol β-D-glucoside (CG), which is produced by the human parasite Helicobacter pylori, provide a possibility to study in vitro the mechanisms of toxicity of these compounds. We studied in detail the effects of CG on the respiratory activities and generation of reactive oxygen species (ROS) by nonsynaptic brain and heart mitochondria oxidizing various substrates. The stimulatory effects of CG on respiration and ROS generation showed strong substrate dependence, suggesting involvement of succinate dehydrogenase (complex II). Maximal effects on ROS production were observed with 1 μmol CG/1 mg mitochondria. At this concentration the cycad toxins β-sitosterol-β-D-glucoside and stigmasterol-β-D-glucoside had effects on respiration and ROS production similar to CG. However, poor solubility precluded full concentration analysis of these toxins. Cholesterol, stigmasterol and β-sitosterol had no effect on mitochondrial functions studied at concentrations up to 100 μmol/mg protein. Our results suggest that CG may influence mitochondrial functions through changes in the packing of the bulk membrane lipids, as was shown earlier by Deliconstantinos et al. (Biochem Cell Biol 67:16-24, 1989). The neurotoxic effects of phytosteryl glucosides and CG may be associated with increased oxidative damage of neurons. Unlike heart mitochondria, in activated neurons mitochondria specifically increase ROS production associated with succinate oxidation (Panov et al., J Biol Chem 284:14448-14456, 2009). PMID:20938651

  1. Antioxidant effects of JM-20 on rat brain mitochondria and synaptosomes: mitoprotection against Ca²⁺-induced mitochondrial impairment.

    PubMed

    Nuñez-Figueredo, Yanier; Pardo-Andreu, Gilberto L; Ramírez-Sánchez, Jeney; Delgado-Hernández, René; Ochoa-Rodríguez, Estael; Verdecia-Reyes, Yamila; Naal, Zeki; Muller, Alexandre Pastoris; Portela, Luis Valmor; Souza, Diogo O

    2014-10-01

    Because mitochondrial oxidative stress and impairment are important mediators of neuronal damage in neurodegenerative diseases and in brain ischemia/reperfusion, in the present study, we evaluated the antioxidant and mitoprotective effect of a new promising neuroprotective molecule, JM-20, in mitochondria and synaptosomes isolated from rat brains. JM-20 inhibited succinate-mediated H₂O₂ generation in both mitochondria and synaptosomes incubated in depolarized (high K(+)) medium at extremely low micromolar concentration and with identical IC₅₀ values of 0.91 μM. JM-20 also repressed glucose-induced H₂O₂ generation stimulated by rotenone or by antimycin A in synaptosomes incubated in high sodium-polarized medium at extremely low IC₅₀ values of 0.395 μM and 2.452 μM, respectively. JM-20 was unable to react directly with H₂O₂ or with superoxide anion radicals but displayed a cathodic reduction peak at -0.71V, which is close to that of oxygen (-0.8V), indicating high electron affinity. JM-20 also inhibited uncoupled respiration in mitochondria or synaptosomes and was a more effective inhibitor in the presence of the respiratory substrates glutamate/malate than in the presence of succinate. JM-20 also prevented Ca(2+)-induced mitochondrial permeability transition pore opening, membrane potential dissipation and cytochrome c release, which are key pathogenic events during stroke. This molecule also prevented Ca(2+) influx into synaptosomes and mitochondria; the former effect was a consequence of the latter because JM-20 inhibition followed the patterns of carbonyl cyanide p-trifluoromethoxyphenyl hydrazone (FCCP), which is a classic mitochondrial uncoupler. Because the mitochondrion is considered an important source and target of neuronal cell death signaling after an ischemic insult, the antioxidant and protective effects of JM-20 against the deleterious effects of Ca(2+) observed at the mitochondrial level in this study may endow this molecule

  2. Acetaminophen from liver to brain: New insights into drug pharmacological action and toxicity.

    PubMed

    Ghanem, Carolina I; Pérez, María J; Manautou, José E; Mottino, Aldo D

    2016-07-01

    Acetaminophen (APAP) is a well-known analgesic and antipyretic drug. It is considered to be safe when administered within its therapeutic range, but in cases of acute intoxication, hepatotoxicity can occur. APAP overdose is the leading cause of acute liver failure in the northern hemisphere. Historically, studies on APAP toxicity have been focused on liver, with alterations in brain function attributed to secondary effects of acute liver failure. However, in the last decade the pharmacological mechanism of APAP as a cannabinoid system modulator has been documented and some articles have reported "in situ" toxicity by APAP in brain tissue at high doses. Paradoxically, low doses of APAP have been reported to produce the opposite, neuroprotective effects. In this paper we present a comprehensive, up-to-date overview of hepatic toxicity as well as a thorough review of both toxic and beneficial effects of APAP in brain. PMID:26921661

  3. Toxicity of the Flame-Retardant BDE-49 on Brain Mitochondria and Neuronal Progenitor Striatal Cells Enhanced by a PTEN-Deficient Background

    PubMed Central

    Giulivi, Cecilia

    2013-01-01

    Polybrominated diphenyl ethers (PBDEs) represent an important group of flame retardants extensively used, tonnage of which in the environment has been steadily increasing over the past 25 years. PBDEs or metabolites can induce neurotoxicity and mitochondrial dysfunction (MD) through a variety of mechanisms. Recently, PBDEs with < 5 Br substitutions (i.e., 2,2′,4,4′-tetrabromodiphenyl ether [BDE-47] and 2,2′,4,5′-tetrabromodiphenyl ether [BDE-49]) have gained interest because of their high bioaccumulation. In particular, congeners such as BDE-49 arise as one of the most biologically active, with concentrations typically lower than those observed for BDE-47 in biological tissues; however, its potential to cause MD at biologically relevant concentrations is unknown. To this end, the effect of BDE-49 was studied in brain mitochondria and neuronal progenitor striatal cells (NPC). BDE-49 uncoupled mitochondria at concentrations < 0.1 nM, whereas at > 1 nM, it inhibited the electron transport at Complex V (mixed type inhibition; IC50 = 6 nM) and Complex IV (noncompetitive inhibition; IC50 = 40 nM). These concentrations are easily achieved in plasma concentrations considering that BDE-49 (this study, 400-fold) and other PBDEs accumulate 1–3 orders of magnitude in the cells, particularly in mitochondria and microsomes. Similar effects were observed in NPC and exacerbated with PTEN (negative modulator of the PI3K/Akt pathway) deficiency, background associated with autism-like behavior, schizophrenia, and epilepsy. PBDE-mediated MD per se or enhanced by a background that confers susceptibility to this exposure may have profound implications in the energy balance of brain. PMID:23288049

  4. Flavin adenine dinucleotide and flavin mononucleotide metabolism in rat liver--the occurrence of FAD pyrophosphatase and FMN phosphohydrolase in isolated mitochondria.

    PubMed

    Barile, M; Brizio, C; De Virgilio, C; Delfine, S; Quagliariello, E; Passarella, S

    1997-11-01

    In order to gain some insight into mitochondrial flavin biochemistry, rat liver mitochondria essentially free of lysosomal and microsomal contamination were prepared and their capability to metabolise externally added and endogenous FAD and FMN tested both spectroscopically and via HPLC. The existence of two novel mitochondrial enzymes, namely FAD pyrophosphatase (EC 3.6.1.18) and FMN phosphohydrolase (EC 3.1.3.2), which catalyse FAD-->FMN and FMN-->riboflavin conversion, respectively, is shown. They differ from each other and from extramitochondrial enzymes, as judged by their pH profile and inhibitor sensitivity, and can be separated in a partial FAD pyrophosphatase purification. Digitonin titration and subfractionation experiments show that FAD pyrophosphatase is located in the outer mitochondrial membrane and FMN phosphohydrolase in the intermembrane space. Since these enzymes can metabolise endogenous FAD and FMN, which are made available by using both Triton X-100 and the effector oxaloacetate, a proposal is made that FAD pyrophosphatase and FMN phosphohydrolase play a major role in mitochondrial flavoprotein turnover. PMID:9395326

  5. The purified and reconstituted ornithine/citrulline carrier from rat liver mitochondria: electrical nature and coupling of the exchange reaction with H+ translocation.

    PubMed Central

    Indiveri, C; Tonazzi, A; Stipani, I; Palmieri, F

    1997-01-01

    The mechanism and the electrical nature of ornithine/citrulline exchange has been investigated in proteoliposomes reconstituted with the ornithine/citrulline carrier purified from rat liver mitochondria. The stoichiometry of the exchanging substrates was close to 1:1. The exchange was not affected by inducing electrogenic flux of K+ with valinomycin. In contrast, the pH gradient generated by the K+/H+ exchanger nigericin in the presence of an outwardly directed K+ gradient stimulated the ornithineout/citrullinein exchange, but not the ornithine/ornithine homoexchange. Experiments in which either the internal or the external pH was varied, while keeping constant the pH in the other compartment, indicated that maximal exchange rates are found at pH 6 in the compartment containing citrulline and at pH 8 in the compartment containing ornithine. Changes in fluorescence of the pH indicator pyranine, included inside the proteoliposomes, showed that the exchanges ornithineout/citrullinein and citrullineout/ornithinein are accompanied by translocation of H+ in the same direction as citrulline. It is concluded that the mitochondrial ornithine/citrulline carrier catalyses an electroneutral exchange of ornithine+ for citrulline plus an H+. A reasonable model is one in which ornithine binds to a deprotonated carrier and citrulline to a protonated carrier and both substrate-carrier complexes are neutral. The physiological implications of this transport process are discussed. PMID:9359400

  6. An eudesman derivative from Verbesina persicifolia D.C. as a natural mild uncoupler in liver mitochondria. A new potential anti-obesity agent?

    PubMed

    Dalla Via, Lisa; García-Argáez, Aída N; Braga, Alessandra; Martínez-Vázquez, Mariano; Grancara, Silvia; Martinis, Pamela; Agostinelli, Enzo; Toninello, Antonio

    2014-01-01

    4β-cinnamoyloxy,1β,3α-dihydroxyeudesm-7,8-ene (CDE) extracted from Verbesina persicifolia induces bioenergetic collapse in rat liver mitochondria (RLM), monitored as a fall in the respiratory control index and ADP/O values. This fall in energy is accompanied by a protonophore effect and membrane potential (Δψ) collapse, demonstrating that CDE behaves as a typical uncoupling agent. However, when examining the effect of CDE in detail, we found that it acts as a "mild" uncoupler because it drops Δψ and increases respiratory state 4. The proposed mechanism is based on the interaction of CDE with membrane protein cytochrome C oxidase, which is implicated in proton permeability, and with the respiratory chain for the generation of reactive oxygen species which mediate and regulate the activity of the above membrane protein. Considering the energy collapse, "mild" uncoupling, and the fact that CDE is largely used in folk medicines, this extract may be viewed as a potentially effective anti-obesity drug and a natural lead compound for developing new natural uncouplers against obesity. PMID:23701541

  7. Brain Natriuretic Peptide in Liver Cirrhosis and Fatty Liver: Correlation with Cardiac Performance

    PubMed Central

    Metwaly, Amna; khalik, Ashraf Abdel; Nasr, Fatma Mohammad; Sabry, Amal Ismail; Gouda, Mohamed Fathy; Hassan, Mona

    2016-01-01

    Objective The aims of the present study were to assess the serum BNP level in patients with post hepatitis C liver cirrhosis and patients with fatty liver and to determine the correlation between BNP and the severity of liver disease and cardiac performance. Methods The study was conducted on 140 subjects subdivided into 3 groups: group 1 included 60 patients having post hepatitis C virus (HCV) liver cirrhosis; group 2 included 60 patients with nonalcoholic fatty liver disease (NAFLD); and group 3 included 20 healthy volunteers serving as a control group. All patients and volunteers were subjected to full physical examinations, laboratory evaluation of hemoglobin percent, liver and renal function tests, serum electrolytes, cholesterol, triglyceride, HBs antigen, HCV antibody and serum BNP levels, ECG, abdominal ultrasonography, and echocardiography. Results There was a significant increase in the BNP level in cirrhotic patients compared to the other two groups (p = 0.000), and it was correlated with the severity of liver disease assigned as Child’s classification (p = 0.000). Also, there was a significant increase in the BNP level in cirrhotic patients with decompensation components compared to those without decompensation components (p = 0.000), history of hepatic encephalopathy (p = 0.000), history of variceal bleeding (p = 0.000), history of spontaneous bacterial peritonitis (p = 0.000), presence of ascites (p = 0.000) and portal vein diameter > 11 mm in abdominal ultrasound (p = 0.000), and prolonged QTc interval in ECG (p = 0.011). There was a significant increase in serum BNP in patients with cirrhosis with the following echocardiographic findings: IVST > 11 mm, PWT > 11 mm, LA diameter > 40 mm, EF% < 54%, and E/A ratio < 1 compared to those without these echocardiographic findings (p = 0.000). Conclusion BNP level increases in post hepatitis C cirrhotic patients and tends to decrease in fatty liver disease patients, and it is correlated with both the

  8. Effects of partial inhibition of respiratory complex I on H2O 2 production by isolated brain mitochondria in different respiratory states.

    PubMed

    Michelini, Luiz G B; Benevento, Carlos E; Rossato, Franco A; Siqueira-Santos, Edilene S; Castilho, Roger F

    2014-12-01

    The aim of this work was to characterize the effects of partial inhibition of respiratory complex I by rotenone on H2O2 production by isolated rat brain mitochondria in different respiratory states. Flow cytometric analysis of membrane potential in isolated mitochondria indicated that rotenone leads to uniform respiratory inhibition when added to a suspension of mitochondria. When mitochondria were incubated in the presence of a low concentration of rotenone (10 nm) and NADH-linked substrates, oxygen consumption was reduced from 45.9 ± 1.0 to 26.4 ± 2.6 nmol O2 mg(-1) min(-1) and from 7.8 ± 0.3 to 6.3 ± 0.3 nmol O2 mg(-1) min(-1) in respiratory states 3 (ADP-stimulated respiration) and 4 (resting respiration), respectively. Under these conditions, mitochondrial H2O2 production was stimulated from 12.2 ± 1.1 to 21.0 ± 1.2 pmol H2O2 mg(-1) min(-1) and 56.5 ± 4.7 to 95.0 ± 11.1 pmol H2O2 mg(-1) min(-1) in respiratory states 3 and 4, respectively. Similar results were observed when comparing mitochondrial preparations enriched with synaptic or nonsynaptic mitochondria or when 1-methyl-4-phenylpyridinium ion (MPP(+)) was used as a respiratory complex I inhibitor. Rotenone-stimulated H2O2 production in respiratory states 3 and 4 was associated with a high reduction state of endogenous nicotinamide nucleotides. In succinate-supported mitochondrial respiration, where most of the mitochondrial H2O2 production relies on electron backflow from complex II to complex I, low rotenone concentrations inhibited H2O2 production. Rotenone had no effect on mitochondrial elimination of micromolar concentrations of H2O2. The present results support the conclusion that partial complex I inhibition may result in mitochondrial energy crisis and oxidative stress, the former being predominant under oxidative phosphorylation and the latter under resting respiration conditions. PMID:25287903

  9. Effect of liposomes on energy-dependent uptake of the antioxidant SkQR1 by isolated mitochondria.

    PubMed

    Antonenko, Yuri N; Perevoshchikova, Irina V; Rokitskaya, Tatyana I; Simonyan, Ruben A; Tashlitsky, Vadim V; Skulachev, Vladimir P

    2012-08-01

    The mitochondria-targeted antioxidant SkQR1 composed of a plastoquinone part covalently bound to a cationic rhodamine 19 moiety via a decane linker was previously shown to effectively protect brain and kidney from ischemia injury accompanying generation of reactive oxygen species. In the present paper the energy-dependent SkQR1 uptake by isolated rat liver mitochondria was studied by fluorescence correlation spectroscopy peak intensity analysis (FCS PIA). This approach can be used to measure the number of fluorescent molecules per single mitochondrion. A large portion of SkQR1 appeared to be taken up by mitochondria in an energy-independent fashion because of its high affinity to membranes. Liposomes were found to compete effectively with mitochondria for the energy-independent SkQR1 binding, thereby facilitating, as an "SkQR1-buffer", observation of energy-dependent SkQR1 accumulation in mitochondria. The rate of energy-dependent SkQR1 uptake by mitochondria observed in the presence of liposomes was rather low (minutes) which was apparently due to slow redistribution of SkQR1 between liposomal and mitochondrial membranes. This can explain the low rate of staining of mitochondria by SkQR1 in living cells containing, besides mitochondria, other membrane components (endoplasmic reticulum, Golgi membranes, endosomes, lysosomes, etc.) which can compete with mitochondria for the energy-independent SkQR1 binding. PMID:22723179

  10. Alteration of Brain Oxygenation During "Piggy Back" Liver Transplantation

    NASA Astrophysics Data System (ADS)

    Panzera, Piercarmine; Greco, Luigi; Carravetta, Giuseppe; Gentile, Antonella; Catalano, Giorgio; Cicco, Giuseppe; Memeo, Vincenzo

    Relevant changes in cerebral circulation occur during "Piggy Back" liver transplantation. Particularly at the washout-reperfusion time the cerebral perfusion suddenly changes from its lowest to its highest values. Further investigation is required to evaluate whether patients with the greatest change in cerebral oxygenation at this time point will suffer neurological complications after transplantation.

  11. Cross-talk between branched-chain amino acids and hepatic mitochondria is compromised in nonalcoholic fatty liver disease

    PubMed Central

    Kalavalapalli, Srilaxmi; Bril, Fernando; Garrett, Timothy J.; Nautiyal, Manisha; Mathew, Justin T.; Williams, Caroline M.; Cusi, Kenneth

    2015-01-01

    Elevated plasma branched-chain amino acids (BCAA) in the setting of insulin resistance have been relevant in predicting type 2 diabetes mellitus (T2DM) onset, but their role in the etiology of hepatic insulin resistance remains uncertain. We determined the link between BCAA and dysfunctional hepatic tricarboxylic acid (TCA) cycle, which is a central feature of hepatic insulin resistance and nonalcoholic fatty liver disease (NAFLD). Plasma metabolites under basal fasting and euglycemic hyperinsulinemic clamps (insulin stimulation) were measured in 94 human subjects with varying degrees of insulin sensitivity to identify their relationships with insulin resistance. Furthermore, the impact of elevated BCAA on hepatic TCA cycle was determined in a diet-induced mouse model of NAFLD, utilizing targeted metabolomics and nuclear magnetic resonance (NMR)-based metabolic flux analysis. Insulin stimulation revealed robust relationships between human plasma BCAA and indices of insulin resistance, indicating chronic metabolic overload from BCAA. Human plasma BCAA and long-chain acylcarnitines also showed a positive correlation, suggesting modulation of mitochondrial metabolism by BCAA. Concurrently, mice with NAFLD failed to optimally induce hepatic mTORC1, plasma ketones, and hepatic long-chain acylcarnitines, following acute elevation of plasma BCAA. Furthermore, elevated BCAA failed to induce multiple fluxes through hepatic TCA cycle in mice with NAFLD. Our data suggest that BCAA are essential to mediate efficient channeling of carbon substrates for oxidation through mitochondrial TCA cycle. Impairment of BCAA-mediated upregulation of the TCA cycle could be a significant contributor to mitochondrial dysfunction in NAFLD. PMID:26058864

  12. Membrane docosahexaenoate is supplied to the developing brain and retina by the liver

    SciTech Connect

    Scott, B.L.; Bazan, N.G. )

    1989-04-01

    Docosahexaenoic acid is concentrated in phospholipids of cellular membranes from brain and retina. Although linolenic acid is the major {omega}3 fatty acid of mouse dams' milk, 22:6 is the prevalent {omega}3 fatty acid in serum and tissues. Intraperitoneal injection of (1-{sup 14}C)18:3 into 3-day-old mouse pups resulted in liver and serum lipid labeling that was initially high, followed by a rapid decline. In contrast, labeling of brain and retinal lipids were initially low and increased with time. Labeled 22:6 first appeared in liver 2 hr after injection and later in brain and retina. The authors suggest that 22:6 synthesized from 18:3 by the liver is secreted into the bloodstream in lipoproteins, taken up by brain and retina, and incorporated into cell membranes. They hypothesize that the 22;6 requirements of membranes (e.g., during synaptogenesis, photoreceptor membrane biogenesis, or repair after ischemic injury or neurodegenerative disorders) are met by a signal that is sent by the appropriate tissues to the liver to evoke the secretion of 22:6-containing lipoproteins.

  13. Impaired Gut-Liver-Brain Axis in Patients with Cirrhosis

    PubMed Central

    Ahluwalia, Vishwadeep; Betrapally, Naga S; Hylemon, Phillip B; White, Melanie B; Gillevet, Patrick M; Unser, Ariel B; Fagan, Andrew; Daita, Kalyani; Heuman, Douglas M; Zhou, Huiping; Sikaroodi, Masoumeh; Bajaj, Jasmohan S

    2016-01-01

    Cirrhosis is associated with brain dysfunction known as hepatic encephalopathy (HE). The mechanisms behind HE are unclear although hyperammonemia and systemic inflammation through gut dysbiosis have been proposed. We aimed to define the individual contribution of specific gut bacterial taxa towards astrocytic and neuronal changes in brain function using multi-modal MRI in patients with cirrhosis. 187 subjects (40 controls, 147 cirrhotic; 87 with HE) underwent systemic inflammatory assessment, cognitive testing, stool microbiota analysis and brain MRI analysis. MR spectroscopy (MRS) changes of increased Glutamate/glutamine, reduced myo-inositol and choline are hyperammonemia-associated astrocytic changes, while diffusion tensor imaging (DTI) demonstrates changes in neuronal integrity and edema. Linkages between cognition, MRI parameters and gut microbiota were compared between groups. We found that HE patients had a significantly worse cognitive performance, systemic inflammation, dysbiosis and hyperammonemia compared to controls and cirrhotics without HE. Specific microbial families (autochthonous taxa negatively and Enterobacteriaceae positively) correlated with MR spectroscopy and hyperammonemia-associated astrocytic changes. On the other hand Porphyromonadaceae, were only correlated with neuronal changes on DTI without linkages with ammonia. We conclude that specific gut microbial taxa are related to neuronal and astrocytic consequences of cirrhosis-associated brain dysfunction. PMID:27225869

  14. Impaired Gut-Liver-Brain Axis in Patients with Cirrhosis.

    PubMed

    Ahluwalia, Vishwadeep; Betrapally, Naga S; Hylemon, Phillip B; White, Melanie B; Gillevet, Patrick M; Unser, Ariel B; Fagan, Andrew; Daita, Kalyani; Heuman, Douglas M; Zhou, Huiping; Sikaroodi, Masoumeh; Bajaj, Jasmohan S

    2016-01-01

    Cirrhosis is associated with brain dysfunction known as hepatic encephalopathy (HE). The mechanisms behind HE are unclear although hyperammonemia and systemic inflammation through gut dysbiosis have been proposed. We aimed to define the individual contribution of specific gut bacterial taxa towards astrocytic and neuronal changes in brain function using multi-modal MRI in patients with cirrhosis. 187 subjects (40 controls, 147 cirrhotic; 87 with HE) underwent systemic inflammatory assessment, cognitive testing, stool microbiota analysis and brain MRI analysis. MR spectroscopy (MRS) changes of increased Glutamate/glutamine, reduced myo-inositol and choline are hyperammonemia-associated astrocytic changes, while diffusion tensor imaging (DTI) demonstrates changes in neuronal integrity and edema. Linkages between cognition, MRI parameters and gut microbiota were compared between groups. We found that HE patients had a significantly worse cognitive performance, systemic inflammation, dysbiosis and hyperammonemia compared to controls and cirrhotics without HE. Specific microbial families (autochthonous taxa negatively and Enterobacteriaceae positively) correlated with MR spectroscopy and hyperammonemia-associated astrocytic changes. On the other hand Porphyromonadaceae, were only correlated with neuronal changes on DTI without linkages with ammonia. We conclude that specific gut microbial taxa are related to neuronal and astrocytic consequences of cirrhosis-associated brain dysfunction. PMID:27225869

  15. Citric Acid Effects on Brain and Liver Oxidative Stress in Lipopolysaccharide-Treated Mice

    PubMed Central

    Youness, Eman R.; Mohammed, Nadia A.; Morsy, Safaa M. Youssef; Omara, Enayat A.; Sleem, Amany A.

    2014-01-01

    Abstract Citric acid is a weak organic acid found in the greatest amounts in citrus fruits. This study examined the effect of citric acid on endotoxin-induced oxidative stress of the brain and liver. Mice were challenged with a single intraperitoneal dose of lipopolysaccharide (LPS; 200 μg/kg). Citric acid was given orally at 1, 2, or 4 g/kg at time of endotoxin injection and mice were euthanized 4 h later. LPS induced oxidative stress in the brain and liver tissue, resulting in marked increase in lipid peroxidation (malondialdehyde [MDA]) and nitrite, while significantly decreasing reduced glutathione, glutathione peroxidase (GPx), and paraoxonase 1 (PON1) activity. Tumor necrosis factor-alpha (TNF-α) showed a pronounced increase in brain tissue after endotoxin injection. The administration of citric acid (1–2 g/kg) attenuated LPS-induced elevations in brain MDA, nitrite, TNF-α, GPx, and PON1 activity. In the liver, nitrite was decreased by 1 g/kg citric acid. GPx activity was increased, while PON1 activity was decreased by citric acid. The LPS-induced liver injury, DNA fragmentation, serum transaminase elevations, caspase-3, and inducible nitric oxide synthase expression were attenuated by 1–2 g/kg citric acid. DNA fragmentation, however, increased after 4 g/kg citric acid. Thus in this model of systemic inflammation, citric acid (1–2 g/kg) decreased brain lipid peroxidation and inflammation, liver damage, and DNA fragmentation. PMID:24433072

  16. Identification of anthocyanins in the liver, eye, and brain of blueberry-fed pigs.

    PubMed

    Kalt, Wilhelmina; Blumberg, Jeffrey B; McDonald, Jane E; Vinqvist-Tymchuk, Melinda R; Fillmore, Sherry A E; Graf, Brigitte A; O'Leary, Jennifer M; Milbury, Paul E

    2008-02-13

    Dietary intervention with anthocyanins may confer benefits in brain function, including vision. Research to date indicates that animals have only a limited capacity to absorb anthocyanins, compared to other types of flavonoids. Pigs, which are a suitable model for human digestive absorption, were used to examine the deposition of anthocyanins in tissues including the liver, eye, and brain tissue. Pigs were fed diets supplemented with 0, 1, 2, or 4% w/w blueberries ( Vaccinium corymbosum L. 'Jersey') for 4 weeks. Prior to euthanasia, pigs were fasted for 18-21 h. Although no anthocyanins were detected in the plasma or urine of the fasted animals, intact anthocyanins were detected in all tissues where they were sought. LC-MS/MS results are presented for the relative concentration of 11 intact anthocyanins in the liver, eye, cortex, and cerebellum. The results suggest that anthocyanins can accumulate in tissues, including tissues beyond the blood-brain barrier. PMID:18211026

  17. Timeline: Mitochondria.

    PubMed

    Evans, Allyson

    2016-03-01

    Mitochondria perform diverse yet interconnected cellular functions and are dynamically regulated by complex signaling pathways. Interest in this fascinating organelle has recently undergone a renaissance due to a series of discoveries revealing that mitochondrial function goes beyond the generation of molecular fuel. This Timeline highlights some of the groundbreaking events over the last 30 years in our understanding of how mitochondria are made and turned over, and how they integrate and signal within the cell and organism. To view this Timeline, open or download the PDF. PMID:26942681

  18. Pituitary and Brain Dopamine D2 Receptors Regulate Liver Gene Sexual Dimorphism

    PubMed Central

    Ramirez, Maria Cecilia; Ornstein, Ana Maria; Luque, Guillermina Maria; Perez Millan, Maria Ines; Garcia-Tornadu, Isabel; Rubinstein, Marcelo

    2015-01-01

    Liver sexual gene dimorphism, which depends mainly on specific patterns of GH secretion, may underlie differential susceptibility to some liver diseases. Because GH and prolactin secretion are regulated by dopaminergic pathways, we studied the participation of brain and lactotrope dopamine 2 receptors (D2Rs) on liver gene sexual dimorphism, to explore a link between the brain and liver gene expression. We used global D2R knockout mice (Drd2−/−) and conducted a functional dissection strategy based on cell-specific Drd2 inactivation in neurons (neuroDrd2KO) or pituitary lactotropes. Disruption of neuronal D2Rs (which impaired the GH axis) decreased most of male or female-predominant class I liver genes and increased female–predominant class II genes in males, consistent with the positive (class I) or negative (class II) regulation of these genes by GH. Notably, sexual dimorphism was lost for class I and II genes in neuroDrd2KO mice. Disruption of lactotrope D2Rs did not modify class I or II genes in either sex, because GH axis was preserved. But surprisingly, 1 class II gene (Prlr) and female-predominant class I genes were markedly up-regulated in lacDrd2KO females, pointing to direct or indirect effects of prolactin in the regulation of selected female-predominant liver genes. This suggestion was strengthened in the hyperprolactinemic Drd2−/− female mouse, in which increased expression of the same 4 liver genes was observed, despite a decreased GH axis. We hereby demonstrate endocrine-mediated D2R actions on sexual dimorphic liver gene expression, which may be relevant during chronic dopaminergic medications in psychiatric disease. PMID:25545383

  19. Detection of Labile Low-Molecular-Mass Transition Metal Complexes in Mitochondria.

    PubMed

    McCormick, Sean P; Moore, Michael J; Lindahl, Paul A

    2015-06-01

    Liquid chromatography was used with an online inductively coupled plasma mass spectrometer to detect low-molecular-mass (LMM) transition metal complexes in mitochondria isolated from fermenting yeast cells, human Jurkat cells, and mouse brain and liver. These complexes constituted 20-40% of total mitochondrial Mn, Fe, Zn, and Cu ions. The major LMM Mn complex in yeast mitochondria, called Mn1100, had a mass of ∼1100 Da and a concentration of ∼2 μM. Mammalian mitochondria contained a second Mn species with a mass of ∼2000 Da at a comparable concentration. The major Fe complex in mitochondria isolated from exponentially growing yeast cells had a mass of ∼580 Da; the concentration of Fe580 in mitochondria was ∼100 μM. When mitochondria were isolated from fermenting cells in postexponential phase, the mass of the dominant LMM Fe complex was ∼1100 Da. Upon incubation, the intensity of Fe1100 declined and that of Fe580 increased, suggesting that the two are interrelated. Mammalian mitochondria contained Fe580 and two other Fe species (Fe2000 and Fe1100) at concentrations of ∼50 μM each. The dominant LMM Zn species in mitochondria had a mass of ∼1200 Da and a concentration of ∼110 μM. Mammalian mitochondria contained a second major LMM Zn species at 1500 Da. The dominant LMM Cu species in yeast mitochondria had a mass of ∼5000 Da and a concentration in yeast mitochondria of ∼16 μM; Cu5000 was not observed in mammalian mitochondria. The dominant Co species in mitochondria, Co1200, had a concentration of 20 nM and was probably a cobalamin. Mammalian but not yeast mitochondria contained a LMM Mo species, Mo730, at a concentration of ∼1 μM. Increasing Mn, Fe, Cu, and Zn concentrations 10-fold in the medium increased the concentration of the same element in the corresponding isolated mitochondria. Treatment with metal chelators confirmed that these LMM species were labile. The dominant S species at 1100 Da was not free glutathione or glutathione

  20. Detection of Labile Low-Molecular-Mass Transition Metal Complexes in Mitochondria

    PubMed Central

    McCormick, Sean P.; Moore, Michael J.; Lindahl, Paul A.

    2015-01-01

    Liquid chromatography was used with an on-line inductively coupled plasma mass spectrometer to detect low-molecular-mass (LMM) transition metal complexes in mitochondria isolated from fermenting yeast cells, human Jurkat cells, and mouse brain and liver. These complexes constituted 20 – 40% of total mitochondrial Mn, Fe, Zn, and Cu ions. The major LMM Mn complex in yeast mitochondria had a mass of ca. 1100 Da and a concentration of ~ 2 μM. Mammalian mitochondria contained a second Mn species with a mass of ca. 2000 Da at a comparable concentration. The major Fe complex in mitochondria isolated from exponentially growing yeast cells had a mass of ca. 580 Da; the concentration of Fe580 in mitochondria was ca. 100 μM. When mitochondria were isolated from fermenting cells in post-exponential phase, the mass of the dominant LMM Fe complex was ca. 1100 Da. Upon incubation, the intensity of Fe1100 declined and Fe580 increased, suggesting that the two are interrelated. Mammalian mitochondria contained Fe580 and 2 other Fe species (Fe2000 and Fe1100) at concentrations of ca. 50 μM each. The dominant LMM Zn species in mitochondria had a mass of ca. 1200 Da and a concentration of ca. 110 μM. Mammalian mitochondria contained a second major LMM Zn species at 1500 Da. The dominant LMM Cu species in yeast mitochondria had a mass of ca. 5000 Da and a concentration in yeast mitochondria of ca. 16 μM; Cu5000 was not observed in mammalian mitochondria. The dominant Co species in mitochondria, Co1200, had a concentration of 20 nM and was probably a cobalamin. Mammalian but not yeast mitochondria contained a LMM Mo species, Mo730, at ca. 1 μM concentration. Increasing Mn, Fe, Cu, and Zn concentrations 10 fold in the medium increased the concentration of the same element in the corresponding isolated mitochondria. Treatment with metal chelators confirmed that these LMM species were labile. The dominant S species at 1100 Da was not free GSH or GSSG. PMID:26018429

  1. A role for 2,4-enoyl-CoA reductase in mitochondrial beta-oxidation of polyunsaturated fatty acids. Effects of treatment with clofibrate on oxidation of polyunsaturated acylcarnitines by isolated rat liver mitochondria.

    PubMed Central

    Osmundsen, H; Cervenka, J; Bremer, J

    1982-01-01

    1. beta-Oxidation of gamma-linolenoylcarnitine, arachidonoylcarnitine and docosahexaenoylcarnitine by isolated rat liver mitochondria is inhibited by uncoupling conditions. Partial re-activation is obtained with added ATP. With mitochondria from clofibrate-treated rats ATP-stimulated rates of beta-oxidation of docosahexaenoylcarnitine are higher than ADP-stimulated rates. This is not observed with the beta-oxidation of oleoylcarnitine. 2. beta-Oxidation of docosahexaenoylcarnitine, in the presence of rotenone, is inhibited by added oxaloacetate, analogous to previous findings with pent-4-enoylcarnitine [see Osmundsen (1978) FEBS Lett. 88, 219-222]. In the absence of rotenone added oxaloacetate stimulates the beta-oxidation of docosahexaenoylcarnitine, but has the opposite effect on the beta-oxidation of palmitoylcarnitine. 3. beta-Oxidation of polyunsaturated acylcarnitines by isolated rat liver mitochondria is selectively increased after treatment of the animals with a low dietary dose (0.2%, w/w) of clofibrate. Treatment with a higher dose of clofibrate (0.5%, w/w) resulted in a general stimulation of beta-oxidation. 4. The results presented suggest that long-chain fatty acids possessing a delta 4-double bond are not readily beta-oxidized unless the 2,4-enoyl-CoA reductase (EC 1.3.1.-) is operating. PMID:7165730

  2. Brain-liver connections: role of the preautonomic PVN neurons.

    PubMed

    O'Hare, James D; Zsombok, Andrea

    2016-02-01

    Diabetes mellitus and the coexisting conditions and complications, including hypo- and hyperglycemic events, obesity, high cholesterol levels, and many more, are devastating problems. Undoubtedly, there is a huge demand for treatment and prevention of these conditions that justifies the search for new approaches and concepts for better management of whole body metabolism. Emerging evidence demonstrates that the autonomic nervous system is largely involved in the regulation of glucose homeostasis; however, the underlying mechanisms are still under investigation. Within the hypothalamus, the paraventricular nucleus (PVN) is in a unique position to integrate neural and hormonal signals to command both the autonomic and neuroendocrine outflow. This minireview will provide a brief overview on the role of preautonomic PVN neurons and the importance of the PVN-liver pathway in the regulation of glucose homeostasis. PMID:26646097

  3. Glycogen phosphorylase isoenzymes from hepatoma 3924A and from a non-tumorigenic liver cell line. Comparison with the liver and brain enzymes.

    PubMed Central

    Mayer, D; Seelmann-Eggebert, G; Letsch, I

    1992-01-01

    Glycogen phosphorylase isoenzymes were isolated from normal rat liver, rat brain, the glycogen-poor Morris hepatoma (MH) 3924A, and the glycogen-rich non-tumorigenic liver cell line C1I. Electrophoretic and immunological characterization of the enzymes showed that tumour and C1I cells expressed a phosphorylase isoform similar to the brain type; the liver type was not detectable. All enzymes were obtained as dimers; the Mr of the subunits was 96,000 (liver), 93,000 (brain and MH 3924A) and 92,000 (C1I). Isoelectric focusing revealed a main band of pI 6.34 for liver phosphorylase a, pI 5.67 for the enzymes from MH 3924A and brain, and pI 5.68 for C1I phosphorylase. Partial kinetic characterization of the AMP-independent forms of the isoenzymes yielded Km values for glucose 1-phosphate of 3.5 +/- 0.5 mM (liver), 3.9 mM (brain), 1.9 +/- 0.3 mM (MH 3924A) and 2.5 +/- 0.5 mM (C1I); Km values for glycogen were 0.4 mM (liver) and 0.3 mM (MH 3924A and C1I), calculated as glucose equivalents. The AMP-independent phosphorylase was inhibited by glucose 6-phosphate (Glc6P) with Ki values of 0.32 +/- 0.03 mM (C1I), 0.50 +/- 0.04 mM (MH 3924A) and approximately 5 mM (brain). The inhibition could be abolished by 1 mM-AMP, indicating that AMP and Glc6P may partially compete for the same site on the protein. Liver phosphorylase a was not inhibited by up to 25 mM-Glc6P. In contrast with liver and brain isoenzymes, phosphorylase from the cell lines was not affected by NaF and Na2SO4. The data show that both the hepatocellular carcinoma and the non-malignant immortalized liver cells express a phosphorylase isoform different from the liver type. Furthermore, there is some evidence that the enzyme from MH 3924A and C1I cells is distinct from brain phosphorylase a, in spite of electrophoretic and immunological resemblance, and that this isoenzyme is subject to altered metabolic regulation. Images Fig. 2. PMID:1554349

  4. Differential characteristics of heart, liver, and brain metastatic subsets of murine breast carcinoma.

    PubMed

    Erin, Nuray; Kale, Sule; Tanrıöver, Gamze; Köksoy, Sadi; Duymuş, Ozlem; Korcum, Aylin F

    2013-06-01

    Breast carcinoma is comprised of heterogeneous groups of cells with different metastatic potential. To develop effective therapeutic strategies targeting metastatic disease, it is crucial to understand the characteristics of breast cancer cells that enable metastasis to distant organs. 4THM breast carcinoma cells are the cells of 4T1 primary tumors that metastasized to the heart. Cells of 4THM tumors which metastasized to liver (4TLM) were previously isolated. Recently macroscopic brain metastasis in 4THM injected animals, were isolated to obtain a brain metastatic cell line (4TBM). Using an orthotopic mouse model differential characteristic of cells metastasized to heart (4THM), liver (4TLM), and brain (4TBM) were compared for ability to metastasize and expression of stem cell markers. We found that 4TLM cells produced significantly more lung and liver metastasis compared to 4TBM and 4THM cells. In vitro, proliferation as well as migration rate of 4TLM cells was also significantly higher than the other cell lines. Remarkably primary tumors formed by 4TLM cells expressed significant amounts of CD34, a marker for mesenchymal malignancies. Markers of epithelial-mesenchymal transition were expressed in all metastatic cells, but the degree of expression differed. Majorities of 4TLM, 4THM, and 4TBM cells were CD44+ CD24- whereas, 12 % of 4TLM cells also expressed membranous CD24. Conditioned mediums of non-metastatic 67NR breast tumors and cancer-associated fibroblasts inhibited growth of highly metastatic 4TLM cells. Malignant cells metastasized to brain were distinguished by membranous E-cadherin expression that was markedly higher in 4TBM cells grown as spheroids suggesting E-cadherin is required for brain metastasis. Differential features of heart, brain, and liver metastatic cells in a syngenic model was shown in this study for the first time. These findings not only provide a model to explore new treatment modalities, but also demonstrate differential features of

  5. Hepatic glycogen can regulate hypoglycemic counterregulation via a liver-brain axis.

    PubMed

    Winnick, Jason J; Kraft, Guillaume; Gregory, Justin M; Edgerton, Dale S; Williams, Phillip; Hajizadeh, Ian A; Kamal, Maahum Z; Smith, Marta; Farmer, Ben; Scott, Melanie; Neal, Doss; Donahue, E Patrick; Allen, Eric; Cherrington, Alan D

    2016-06-01

    Liver glycogen is important for the counterregulation of hypoglycemia and is reduced in individuals with type 1 diabetes (T1D). Here, we examined the effect of varying hepatic glycogen content on the counterregulatory response to low blood sugar in dogs. During the first 4 hours of each study, hepatic glycogen was increased by augmenting hepatic glucose uptake using hyperglycemia and a low-dose intraportal fructose infusion. After hepatic glycogen levels were increased, animals underwent a 2-hour control period with no fructose infusion followed by a 2-hour hyperinsulinemic/hypoglycemic clamp. Compared with control treatment, fructose infusion caused a large increase in liver glycogen that markedly elevated the response of epinephrine and glucagon to a given hypoglycemia and increased net hepatic glucose output (NHGO). Moreover, prior denervation of the liver abolished the improved counterregulatory responses that resulted from increased liver glycogen content. When hepatic glycogen content was lowered, glucagon and NHGO responses to insulin-induced hypoglycemia were reduced. We conclude that there is a liver-brain counterregulatory axis that is responsive to liver glycogen content. It remains to be determined whether the risk of iatrogenic hypoglycemia in T1D humans could be lessened by targeting metabolic pathway(s) associated with hepatic glycogen repletion. PMID:27140398

  6. Hepatic glycogen can regulate hypoglycemic counterregulation via a liver-brain axis

    PubMed Central

    Kraft, Guillaume; Williams, Phillip; Hajizadeh, Ian A.; Kamal, Maahum Z.; Smith, Marta; Farmer, Ben; Scott, Melanie; Neal, Doss; Donahue, E. Patrick; Allen, Eric; Cherrington, Alan D.

    2016-01-01

    Liver glycogen is important for the counterregulation of hypoglycemia and is reduced in individuals with type 1 diabetes (T1D). Here, we examined the effect of varying hepatic glycogen content on the counterregulatory response to low blood sugar in dogs. During the first 4 hours of each study, hepatic glycogen was increased by augmenting hepatic glucose uptake using hyperglycemia and a low-dose intraportal fructose infusion. After hepatic glycogen levels were increased, animals underwent a 2-hour control period with no fructose infusion followed by a 2-hour hyperinsulinemic/hypoglycemic clamp. Compared with control treatment, fructose infusion caused a large increase in liver glycogen that markedly elevated the response of epinephrine and glucagon to a given hypoglycemia and increased net hepatic glucose output (NHGO). Moreover, prior denervation of the liver abolished the improved counterregulatory responses that resulted from increased liver glycogen content. When hepatic glycogen content was lowered, glucagon and NHGO responses to insulin-induced hypoglycemia were reduced. We conclude that there is a liver-brain counterregulatory axis that is responsive to liver glycogen content. It remains to be determined whether the risk of iatrogenic hypoglycemia in T1D humans could be lessened by targeting metabolic pathway(s) associated with hepatic glycogen repletion. PMID:27140398

  7. Multiple Brain Abscesses Due to Aspergillus Fumigatus in a Patient With Liver Cirrhosis: A Case Report.

    PubMed

    Tang, Hung-Jen; Liu, Wei-Lun; Chang, Tsung Chain; Li, Ming-Chi; Ko, Wen-Chien; Wu, Chi-Jung; Chuang, Yin-Ching; Lai, Chih-Cheng

    2016-03-01

    Invasive cerebral aspergillosis always developed in immunocompromised host. Early diagnosis may save life in this critical condition; however, it is difficult to reach. Herein, we presented an unusual case of invasive cerebral aspergillosis in a cirrhotic patient. A 47-year-old man presented with progressive deterioration of consciousness for three days. The patient had a history of alcoholic liver cirrhosis, Child-Pugh class C. Magnetic resonance imaging (MRI) of brain showed multi-focal parenchymal lesions, which was consistent with multiple brain abscesses. The diagnosis of invasive cerebral aspergillosis was made by molecular based laboratory methods including Aspergillus galactomannan antigen assay and oligonucleotide array. Despite treatment with the antifungal agent, Amphotericin B, the patient died at the ninth day of hospitalization. Our findings suggest that liver cirrhosis can be one of risk factors of invasive cerebral aspergillosis, and support the diagnosing usefulness of MRI, Aspergillus galactomannan antigen assay, and oligonucleotide array. PMID:26945363

  8. Evaluation of neurologic complications by brain MRI in kidney and liver transplant recipients.

    PubMed

    Agildere, A M; Başaran, C; Cakir, B; Ozgül, E; Kural, F; Haberal, M

    2006-03-01

    The aim of this study was to retrospectively analyze brain magnetic resonance imaging (MRI) findings in patients who developed neurologic complications after liver and kidney transplantation. The results in 216 organ transplant recipients, who had brain MRI were evaluated retrospectively. We performed 187 brain MRI on kidney recipients and 29 liver recipients. Neuroradiologic findings were classified in three groups: group 1 findings were related to transplantation; group 2 findings, to chronic parenchymal disease; and group 3 to neither transplantation nor chronic parenchymal disease. In group 1, six patients (20.6%) after liver and three (1.6%) after kidney transplantation had posterior reversible encephalopathy syndrome; two patients (1.1%) after renal and one (3.4%) after liver transplantation had tuberculosis granulomas; one patient (0.5%) after renal transplantation had osmotic demyelination syndrome; one patient (0.5%) had a Nocardia abcess and one (0.5%) focal cerebritis after renal transplantation. Among group 2, 38 patients (20.3%) had brain atrophy; 37 (20%), white matter changes; 3 (1.6%), sinus thrombosis; 8 (4.3%), lacunar infarct; 1 (0.5%), had renal osteodystrophy in the cranial bones; and 4 (2.2%), had intracranial hemorrhage secondary to end-stage renal disease. Brain atrophy in nine patients (31%), hyperintensity in the globus pallidus on T1-weighted MR images owing to manganese deposits in nine patients (31%), hyperintensity in basal ganglia on T2-weighted MR images owing to copper depositions in one patient (3.4%) were seen secondary to chronic liver disease. In group 3, three patients (1.6%) had intracranial lipomas; one (0.5%), mesial temporal sclerosis; and one (0.5%), an anterior cerebral artery aneurysm in renal transplant patients. Periventricular and subcortical white matter hyperintensities were observed on T2-weighted MR images in six liver transplant patients (20.7%). Neurologic complications after organ transplantation may be

  9. Thyroid hormone therapy and procurement of livers from brain-dead donors.

    PubMed

    Novitzky, Dimitri; Mi, Zhibao; Videla, Luis A; Collins, Joseph F; Cooper, David K C

    2016-08-01

    Hormonal therapy to brain-dead potential organ donors remains controversial. A retrospective study was carried out of hormonal therapy on procurement of organs in 63,593 donors in whom information on T3/T4 therapy was available. In 40,124 donors, T3/T4 and all other hormonal therapy was recorded. The percentages of all organs procured, except livers, were greater in T3/T4-treated donors. Nevertheless, if T3/T4 therapy had been administered to the donor, liver transplantation was associated with significantly increased graft and recipient survival at 1 month and 12 months. The potential reasons for the lack of effect of T3/T4 therapy on the number of livers procured are discussed. PMID:26853445

  10. Protective effect of Xingnaojia formulation on rats with brain and liver damage caused by chronic alcoholism

    PubMed Central

    LI, SHUANG; WANG, SU; GUO, ZHI-GANG; HUANG, NING; ZHAO, FAN-RONG; ZHU, MO-LI; MA, LI-JUAN; LIANG, JIN-YING; ZHANG, YU-LIN; HUANG, ZHONG-LIN; WAN, GUANG-RUI

    2015-01-01

    The aim of this study was to observe the effect of a formulation of traditional Chinese medicine extracts known as Xingnaojia (XNJ) on the liver function, learning ability and memory of rats with chronic alcoholism and to verify the mechanism by which it protects the brain and liver. A rat model of chronic alcoholism was used in the study. The spatial learning ability and memory of the rats were tested. The rats were then sacrificed and their brains and hepatic tissues were isolated. The activity of superoxide dismutase (SOD) and levels of glutamate (Glu), N-methyl D-aspartate receptor subtype 2B (NR2B), cyclin-dependent kinase 5 (CDK5) and cannabinoid receptor 1 (CB1) in the hippocampus were analyzed. The ultrastructure of the hepatic tissue was observed by electron microscopy. In addition, the activities of alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) in serum were tested and the levels of low-density lipoprotein (LDL), high-density lipoprotein (HDL), triglycerides (TG) and total cholesterol (TCHOL) were analyzed. XNJ enhanced the learning and memory of rats with chronic alcoholism. Treatment with XNJ increased the activity of SOD, and decreased the expression levels of NR2B mRNA and NR2B, CB1 and CDK5 proteins in the brain tissues compared with those in the model rats. It also increased the activity of ALDH in the serum and liver, decreased the serum levels of LDL, TG and TCHOL and increased the serum level of HDL. These results indicate that XNJ exhibited a protective effect against brain and liver damage in rats with chronic alcoholism. PMID:26640531

  11. [PROTEIN CONTENT CHANGES IN RATS' LIVER AND BRAIN UNDER CHRONIC ALCOHOL INTOXICATION].

    PubMed

    Raksha, N G; Savchuk, A N; Kharchenko, O I; Galenova, T I; Ostapchenko, L I

    2015-01-01

    An electrophoretic investigation of quantitative protein content in rat's' tissyes under chronic alcoholic intoxication has been done. It was shown the significant increase of protein content with molecular mass 55, 48-50, 43-45, 39-41 KDa and the decrease-of protein fractions with molecular mass 46-48, 34-35, 27-30, 16-18 KDa accordingly in liver and brain homogenates of experimental animals. PMID:26827457

  12. Saponin-permeabilization is not a viable alternative to isolated mitochondria for assessing oxidative metabolism in hibernation.

    PubMed

    Mathers, Katherine E; Staples, James F

    2015-01-01

    Saponin permeabilization of tissue slices is increasingly popular for characterizing mitochondrial function largely because it is fast, easy, requires little tissue and leaves much of the cell intact. This technique is well described for mammalian muscle and brain, but not for liver. We sought to evaluate how saponin permeabilization reflects aspects of liver energy metabolism typically assessed in isolated mitochondria. We studied the ground squirrel (Ictidomys tridecemlineatus Mitchell), a hibernating mammal that shows profound and acute whole-animal metabolic suppression in the transition from winter euthermia to torpor. This reversible metabolic suppression is also reflected in the metabolism of isolated liver mitochondria. In this study we compared euthermic and torpid animals using saponin permeabilized tissue and mitochondria isolated from the same livers. As previously demonstrated, isolated mitochondria have state 3 respiration rates, fueled by succinate, that are suppressed by 60-70% during torpor. This result holds whether respiration is standardized to mitochondrial protein, cytochrome a content or citrate synthase activity. In contrast, saponin-permeabilized liver tissue, show no such suppression in torpor. Neither citrate synthase activity nor VDAC content differ between torpor and euthermia, indicating that mitochondrial content remains constant in both permeabilized tissue and isolated mitochondria. In contrast succinate dehydrogenase activity is suppressed during torpor in isolated mitochondria, but not in permeabilized tissue. Mechanisms underlying metabolic suppression in torpor may have been reversed by the permeabilization process. As a result we cannot recommend saponin permeabilization for assessing liver mitochondrial function under conditions where acute changes in metabolism are known to occur. PMID:25979709

  13. Saponin-permeabilization is not a viable alternative to isolated mitochondria for assessing oxidative metabolism in hibernation

    PubMed Central

    Mathers, Katherine E.; Staples, James F.

    2015-01-01

    ABSTRACT Saponin permeabilization of tissue slices is increasingly popular for characterizing mitochondrial function largely because it is fast, easy, requires little tissue and leaves much of the cell intact. This technique is well described for mammalian muscle and brain, but not for liver. We sought to evaluate how saponin permeabilization reflects aspects of liver energy metabolism typically assessed in isolated mitochondria. We studied the ground squirrel (Ictidomys tridecemlineatus Mitchell), a hibernating mammal that shows profound and acute whole-animal metabolic suppression in the transition from winter euthermia to torpor. This reversible metabolic suppression is also reflected in the metabolism of isolated liver mitochondria. In this study we compared euthermic and torpid animals using saponin permeabilized tissue and mitochondria isolated from the same livers. As previously demonstrated, isolated mitochondria have state 3 respiration rates, fueled by succinate, that are suppressed by 60-70% during torpor. This result holds whether respiration is standardized to mitochondrial protein, cytochrome a content or citrate synthase activity. In contrast, saponin-permeabilized liver tissue, show no such suppression in torpor. Neither citrate synthase activity nor VDAC content differ between torpor and euthermia, indicating that mitochondrial content remains constant in both permeabilized tissue and isolated mitochondria. In contrast succinate dehydrogenase activity is suppressed during torpor in isolated mitochondria, but not in permeabilized tissue. Mechanisms underlying metabolic suppression in torpor may have been reversed by the permeabilization process. As a result we cannot recommend saponin permeabilization for assessing liver mitochondrial function under conditions where acute changes in metabolism are known to occur. PMID:25979709

  14. Steady-state redox behavior of cytochrome c, cytochrome a, and CuA of cytochrome c oxidase in intact rat liver mitochondria.

    PubMed

    Morgan, J E; Wikström, M

    1991-01-29

    We have examined the steady-state redox behavior of cytochrome c (Fec), Fea, and CuA of cytochrome c oxidase during steady-state turnover in intact rat liver mitochondria under coupled and uncoupled conditions. Ascorbate was used as the reductant and TMPD (N,N,N',N'-tetramethyl-1,4-phenylenediamine) as the redox mediator. After elimination of spectroscopic interference from the oxidized form of TMPD, we found that Fea remains significantly more oxidized than previously thought. During coupled turnover, CuA always appears to be close to redox equilibrium with Fec. By increasing the amount of TMPD, both centers can be driven to fairly high levels of reduction while Fea remains relatively oxidized. The reduction level at Fea is close to a linear function of the enzyme turnover rate, but the levels at Fec and CuA do not keep pace with enzyme turnover. This behavior can be explained in terms of a redox equilibrium among Fec, CuA, and Fea, where Fea is the electron donor to the oxygen reduction site, but only if Fea has an effective Em (redox midpoint potential) of 195 mV. This is too low to be accounted for on the basis of nonturnover measurements and the effects of the membrane potential. However, if there is no equilibrium, the internal CuA----Fea electron-transfer rate constant must be slow in the time average (about 200 s-1). Other factors which might contribute to such a low Em are discussed. In the presence of uncoupler, this situation changes dramatically. Both Fec and CuA are much less reduced; within the resolution of our measurements (about 10%), we were unable to measure any reduction of CuA. Fea and CuA remain too oxidized to be in redox equilibrium with Fec during steady-state turnover. Furthermore, our results indicate that, in the uncoupled system, the (time-averaged) internal electron-transfer rate constants in cytochrome oxidase must be of the order of 2500 s-1 or higher. When turnover is slowed by azide, the relative redox levels at Fea and Fec are

  15. Effects of the mode of addition of acyl-CoA on the initial rate of formation of acylcarnitine in the presence of carnitine by intact rat liver mitochondria in vitro.

    PubMed Central

    Zammit, V A

    1985-01-01

    Time courses for the formation of palmitoylcarnitine from palmitoyl-CoA and carnitine, catalysed by the overt activity of carnitine palmitoyltransferase (CPT I) in rat liver mitochondria, were obtained. Significant initial non-linearity was observed only when reactions were started by addition of a concentrated solution of palmitoyl-CoA (4mM, to give a final concentration of 100 microM) uncomplexed to albumin. Minimal effects were observed when the reactions were started by addition of palmitoyl-CoA-albumin mixtures, even though the final palmitoyl-CoA/albumin molar ratios in the assay medium were identical in the two sets of experiments. PMID:4038262

  16. UPTAKE OF [3H]-COLCHICINE INTO BRAIN AND LIVER OF MOUSE, RAT, AND CHICK

    SciTech Connect

    Bennett, Edward L.; Alberti, Marie Hebert; Flood, James F.

    1980-07-01

    The uptake of [ring A-4-{sup 3}H] colchicine and [ring C-methoxy-{sup 3}H]colchicine has been compared in mice from 1 to 24 hr after administration. Less radioactivity was found in brain after administration of ring-labeled colchicine than after administration of the methoxy-labeled colchicine. Three hr after administration of ring-labeled colchicine, 5% of the label was in liver and about 0.01% of the label was present in brain. Forty percent of the brain radioactivity was bound to tubulin as determined by vinblastine precipitation. After 3 hr, an average of 8% of the radioactivity from methoxy-labeled colchicine was found in the liver and 0.16% in brain. However, less than 5% of the activity in brain was precipitated by vinblastine, and the colchicine equivalent was comparable to that found after administration of the ring-labeled colchicine. The amount of colchicine entering mouse brain after subcutaneous injection is comparable to the minimum behaviorally effective dose when administered to the caudate. The metabolism of [ring C-methoxy-{sup 3}H] and [ring A-{sup 3}H]colchicine was also studied in rats. the general pattern was similar to mice; less radioactivity was found in brain after administration of the ring-labeled alkoloid than after administration of methoxy-labeled colchicine. Again, 40-50% of ring-labeled colchicine was precipitated by vinblastine. A much smaller percentage of the methoxy-labeled drug was precipitated by vinblastine than of the ring A-labeled colchicine. These experiments, together with behavioral experiments [7], support the hypotheses that structural alteration in synapses by recently synthesized proteins which are transported down the axons and dendrites may be an essential process for long-term memory formation.

  17. Uptake of (/sup 3/H)colchicine into brain and liver of mouse, rat, and chick

    SciTech Connect

    Bennett, E.L.; Alberti, M.H.; Flood, J.F.

    1981-01-01

    The uptake of (ring A-4-/sup 3/H) colchicine and (ring C-methoxy-/sup 3/H)colchicine has been compared in mice from 1 to 24 hr after administration. Less radioactivity was found in brain after administration of ring-labeled colchicine than after administration of the methoxy-labeled colchicine. Three hr after administration of ring-labeled colchicine, 5% of the label was in liver and about 0.01% of the label was present in brain. Forty percent of the brain radioactivity was bound to tubulin as determined by vinblastine precipitation. After 3 hr, an average of 8% of the radioactivity from methoxy-labeled colchicine was found in the liver and 0.16% in brain. However, less than 5% of the activity in brain was precipitated by vinblastine, and the colchicine equivalent was comparable to that found after administration of the ring-labeled colchicine. The amount of colchicine entering mouse brain after subcutaneous injection is comparable to the minimum behaviorally effective dose when administered to the caudate. The metabolism of (ring C-methoxy-/sup 3/H) and (ring A-/sup 3/H)colchicine was also studied in rats. The general pattern was similar to mice; less radioactivity was found in brain after administration of the ring-labeled alkaloid than after administration of methoxy-labeled colchicine. Again, 40-50% of ring-labeled colchicine was precipitated by vinblastine. A much smaller percentage of the methoxy-labeled drug was precipitated by vinblastine than of the ring A-labeled colchicine. These experiments, together with behavioral experiments, support the hypotheses that structural alterations in synapses by recently synthesized proteins which are transported down the axons and dendrites may be an essential process for long-term memory formation.

  18. Bumetanide increases manganese accumulation in the brain of rats with liver damage.

    PubMed

    Montes, Sergio; Castro-Chávez, Armando; Florian-Soto, Circe; Heras-Romero, Yessica; Ríos, Camilo; Rivera-Mancía, Susana

    2016-03-01

    Hepatic encephalopathy is a common complication in cases of liver damage; it results from several factors, including the accumulation of toxic substances in the brain, e.g. manganese, ammonia and glutamine. We have previously reported that manganese favors ammonia and glutamine accumulation in the brain of cirrhotic rats, and we suggested that such effect could be mediated by manganese-elicited activation of the NKCC1 (Na(+)/K(+)/2Cl(-) cotransporter 1). To test this hypothesis, we used bumetanide, an NKCC1 blocker prescribed to treat ascites in cirrhotic patients; we expected that if NKCC1 was responsible for manganese-mediated ammonia buildup and the subsequent glutamine accumulation, bumetanide could counteract such effect and improve motor coordination. In addition, we considered essential to test the effect of bumetanide on manganese brain levels. We used a model of liver damage in rats, consisting in bile-duct ligation. Animals were exposed to manganese in the drinking water (1 mg/ml) for two weeks and ammonia in the food (20% w/w of ammonia acetate) during the second week after surgery. Bumetanide was administered intraperitoneally in the course of the ammonia treatment. We measured glutamine and manganese in three brain regions: frontal cortex, striatum and cerebellum. Bumetanide produced no effect on glutamine accumulation; however, because of bumetanide treatment, manganese was increased in the brain, and also the activity of gamma-glutamyl transferase in plasma; thus, we consider that the influence of bumetanide and similar diuretics on liver function and manganese homeostasis should be further studied. PMID:26851372

  19. Newcastle disease virus (NDV) induces protein oxidation and nitration in brain and liver of chicken: Ameliorative effect of vitamin E.

    PubMed

    Venkata Subbaiah, Kadiam C; Valluru, Lokanatha; Rajendra, Wudayagiri; Ramamurthy, Chiteti; Thirunavukkarusu, Chinnasamy; Subramanyam, Rajagopal

    2015-07-01

    The present study was aimed at investigating the therapeutic efficacy of vitamin E on oxidative injury in brain and liver of Newcastle disease virus (NDV) challenged chickens. We have analyzed the xanthine oxidase (XOD) activity; uric acid (UA) levels and superoxide radical generation by using electron spin resonance spectroscopy. Further, protein oxidation, nitration and apoptosis were evaluated in the brain and liver of the control, NDV-infected and NDV+Vit. E treated groups. A significant elevation was observed in XOD activity and UA levels in brain (p<0.001) and liver (p<0.05) of NDV infected birds when compared to controls. Further, significant increase in the production of superoxides, enhanced intracellular protein carbonyls and nitrates were observed in the brain and liver of NDV-infected birds over healthy subjects. Apoptosis studies also suggested that a larger number of TUNEL positive cells were observed in brain and a moderately in liver of NDV-infected chickens. However, all these perturbations were significantly ameliorated in NDV+Vit. E treated chickens as compared to NDV-infected birds. Taken together, our results suggested that NDV-induced neuronal and hepatic damage at least in part mediates oxidative stress and on the other hand, supplementation of vitamin E mitigates NDV-induced oxidative damage thereby protects brain and liver of chickens. These findings could provide new insights into the understanding of NDV pathogenesis and therapeutic effects of dietary antioxidants. PMID:25849457

  20. Increased blood-brain transfer in a rabbit model of acute liver failure

    SciTech Connect

    Horowitz, M.E.; Schafer, D.F.; Molnar, P.; Jones, E.A.; Blasberg, R.G.; Patlak, C.S.; Waggoner, J.; Fenstermacher, J.D.

    1983-05-01

    The blood-to-brain transfer of (/sup 14/C)alpha-aminoisobutyric acid was investigated by quantitative autoradiography in normal rabbits and rabbits with acute liver failure induced by the selective hepatotoxin galactosamine. The blood-to-brain transfer of alpha-aminoisobutyric acid was similar in control animals and animals 2 and 7 h after galactosamine injections, but was increased five- to tenfold in certain gray-matter areas of the brain in animals 11 and 18 h after galactosamine treatment. No detectable differences in white-matter uptake of (/sup 14/C)alpha-aminoisobutyric acid were found between the control and treated groups. The increase in alpha-aminoisobutyric acid transfer within the gray-matter areas suggested that a general or nonspecific increase in brain capillary permeability occurred in these areas. No clinical signs of early hepatic encephalopathy were observed in the treated rabbits, except for 1 animal from the 18-h postgalactosamine group. Thus, enhanced blood-brain transfer of alpha-aminoisobutyric acid preceded the development of overt hepatic encephalopathy. The distribution of radioactivity after the intravenous administration of (/sup 14/C)galactosamine showed that virtually none of the hepatotoxin localized in the brain, suggesting that the drug itself does not have a direct effect upon the blood-brain barrier or the brain. The increased uptake of alpha-aminoisobutyric acid at 11 and 18 h implies that the transfer of other solutes would also be enhanced, that central nervous system homeostasis would be compromised, and that the resulting changes in brain fluid composition could contribute to or cause hepatic encephalopathy.

  1. Hypoxia disrupts gene modulation along the brain-pituitary-gonad (BPG)-liver axis.

    PubMed

    Lu, Xiaoying; Yu, Richard M K; Murphy, Margaret B; Lau, Karen; Wu, Rudolf S S

    2014-04-01

    Hypoxia alters sex hormone concentrations leading to reproductive impairment in fish; however the mechanisms underlying these effects remain largely unknown. Using zebrafish (Danio rerio), this study is the first to demonstrate that hypoxia causes endocrine disruption by simultaneously acting on multiple targets along the brain-pituitary-gonadal (BPG)-liver axis in fish. Alterations in the expression of key genes associated with reproductive endocrine pathways in the brain (sGnRH), pituitary (FSHβ and LHβ), gonads (FSH-R, LH-R, HMGR, StAR, CYP19A, CYP11A, CYP11β and 20β-HSD), and liver were correlated with significant reductions of estradiol in females and testosterone in males. Hypoxia also induced sex-specific and tissue-specific changes in the expression of estrogen, androgen, and membrane progestin receptors along the BPG axis, suggesting disruption of the feedback and synchronization of hormone signals. Furthermore, the hypoxia-induced upregulation of hepatic sex hormone-binding globulin suggests an increase in hormone transport and reduced bioavailability in blood, while upregulation of hepatic CYP3A65 and CYP1A in females suggests an increase in estrogen biotransformation and clearance. Given that the regulation of reproductive hormones and the BPG-liver axis are highly conserved, this study provides new insights into the hypoxia-induced endocrine disrupting mechanisms and reproductive impairment in other vertebrates. PMID:24580824

  2. Concentration of organochlorines in human brain, liver, and adipose tissue autopsy samples from Greenland.

    PubMed Central

    Dewailly, E; Mulvad, G; Pedersen, H S; Ayotte, P; Demers, A; Weber, J P; Hansen, J C

    1999-01-01

    Organochlorines are persistent lipophilic compounds that accumulate in Inuit people living in circumpolar countries. Organochlorines accumulate as a result of the Inuits' large consumption of sea mammal fat; however, available data are limited to blood lipids, milk fat, and adipose tissue. We report results of organochlorine determination in liver, brain, omental fat, and subcutaneous abdominal fat samples collected from deceased Greenlanders between 1992 and 1994. Eleven chlorinated pesticides and 14 polychlorinated biphenyl congeners were measured in tissue lipid extracts by high-resolution gas chromatography with electron capture detection. Mean concentrations of polychlorinated biphenyls, 2, 2'-bis(4-chlorophenyl)-1,1-dichloroethylene, ss-hexachlorocyclohexane, hexachlorobenzene, mirex, trans-nonachlor, and oxychlordane in adipose tissue samples from Greenlanders were 3-34-fold higher than those measured using the same analytical method in samples from Canadians in Quebec City, Quebec. Brain lipids contained lower concentrations of all organochlorines than lipids extracted from other tissues. Organochlorine residue levels in lipid extracts from liver, omental fat, and subcutaneous abdominal fat samples were similar, with the exception of ss-hexachlorocyclohexane, which reached a greater concentration in liver lipids than in lipids from both adipose tissues (4-fold; p < 0. 05). Comparisons with available international data on adipose tissue levels reveal that the organochlorine body burden in the Inuit population of Greenland is presently among the highest resulting from environmental exposure. Images Figure 1 PMID:10504150

  3. The chemoprotection of a blueberry anthocyanin extract against the acrylamide-induced oxidative stress in mitochondria: unequivocal evidence in mice liver.

    PubMed

    Zhao, Mengyao; Wang, Pengpu; Zhu, Yuchen; Liu, Xin; Hu, Xiaosong; Chen, Fang

    2015-09-01

    Acrylamide (AA) is one of the most important contaminants occurring in heated food products. Accumulating evidence indicates that AA-induced toxicity is associated with oxidative stress and long-term exposure to AA induced mitochondria collapse and finally leads to apoptosis. Whereas anthocyanins are natural antioxidants and have a strong ability to reduce oxidative damage in vivo. This study investigates the protection of a blueberry anthocyanin extract (BAE) against AA-induced mitochondrial oxidative stress in mice models. The activities of electron transport chain complexes, oxidative status, and the structure and function of mitochondria were measured. Results showed that pretreatment with BAE markedly inhibited reactive oxygen species (ROS) formation, and prevented the successive events associated with the mitochondrial damage and dysfunction, including recovered activities of electron transport chain, ATPase and superoxide dismutase, ameliorated depolarization of mitochondrial membrane potential and membrane lipid peroxidation, reduced release of cytochrome c and protection of mitochondria against swelling. In a word, mitochondria are a key target at the organelle level for the protective effect of BAE against AA toxicity. These results will be helpful to provide new clues for a better understanding of the AA toxicity intervention mechanism and for exploring effective dietary constituents for intervention of AA toxicity. PMID:26190321

  4. TIMP-1 attenuates blood–brain barrier permeability in mice with acute liver failure

    PubMed Central

    Chen, Feng; Radisky, Evette S; Das, Pritam; Batra, Jyotica; Hata, Toshiyuki; Hori, Tomohide; Baine, Ann-Marie T; Gardner, Lindsay; Yue, Mei Y; Bu, Guojun; del Zoppo, Gregory; Patel, Tushar C; Nguyen, Justin H

    2013-01-01

    Blood–brain barrier (BBB) dysfunction in acute liver failure (ALF) results in increased BBB permeability that often precludes the patients from obtaining a life-saving liver transplantation. It remains controversial whether matrix metalloproteinase-9 (MMP-9) from the injured liver contributes to the deregulation of BBB function in ALF. We selectively upregulated a physiologic inhibitor of MMP-9 (TIMP-1) with a single intracerebroventricular injection of TIMP-1 cDNA plasmids at 48 and 72 hours, or with pegylated-TIMP-1 protein. Acute liver failure was induced with tumor necrosis factor-α and 𝒟-(+)-galactosamine in mice. Permeability of BBB was assessed with sodium fluorescein (NaF) extravasation. We found a significant increase in TIMP-1 within the central nervous system (CNS) after the administration of TIMP-1 cDNA plasmids and that increased TIMP-1 within the CNS resulted in an attenuation of BBB permeability, a reduction in activation of epidermal growth factor receptor and p38 mitogen-activated protein kinase signals, and a restoration of the tight junction protein occludin in mice with experimental ALF. Pegylated TIMP-1 provided similar protection against BBB permeability in mice with ALF. Our results provided a proof of principle that MMP-9 contributes to the BBB dysfunction in ALF and suggests a potential therapeutic role of TIMP-1 in ALF. PMID:23532086

  5. Vasopressin receptors in the brain, liver and kidney of rats following osmotic stimulation.

    PubMed

    Landgraf, R; Szot, P; Dorsa, D M

    1991-03-29

    The binding site concentration (Bmax) and equilibrium dissociation constant (Kd) for [3H]-arginine vasopressin (AVP) binding sites were measured in limbic brain areas (septum, dorsal hippocampus, amygdala) and liver and kidney of control and osmotically stimulated male Wistar rats. Membrane binding was performed in these five areas 30, 60 and 180 min following intraperitoneal injection of hypertonic saline. This paradigm resulted in no significant change in binding characteristics in the septum, dorsal hippocampus, amygdala and liver from control treated rats. In contrast, the kidney Bmax was significantly reduced 60 min following osmotic stimulation, with no effect on affinity. These results also suggest that AVP receptors in the CNS are relatively resistant to regulatory effects of an acute AVP exposure. PMID:1828184

  6. Metallothionein (MT) -I and MT-II Expression Are Induced and Cause Zinc Sequestration in the Liver after Brain Injury

    PubMed Central

    Pankhurst, Michael W.; Gell, David A.; Butler, Chris W.; Kirkcaldie, Matthew T. K.; West, Adrian K.; Chung, Roger S.

    2012-01-01

    Experiments with transgenic over-expressing, and null mutant mice have determined that metallothionein-I and -II (MT-I/II) are protective after brain injury. MT-I/II is primarily a zinc-binding protein and it is not known how it provides neuroprotection to the injured brain or where MT-I/II acts to have its effects. MT-I/II is often expressed in the liver under stressful conditions but to date, measurement of MT-I/II expression after brain injury has focused primarily on the injured brain itself. In the present study we measured MT-I/II expression in the liver of mice after cryolesion brain injury by quantitative reverse-transcriptase PCR (RT-PCR) and enzyme-linked immunosorbent assay (ELISA) with the UC1MT antibody. Displacement curves constructed using MT-I/II knockout (MT-I/II−/−) mouse tissues were used to validate the ELISA. Hepatic MT-I and MT-II mRNA levels were significantly increased within 24 hours of brain injury but hepatic MT-I/II protein levels were not significantly increased until 3 days post injury (DPI) and were maximal at the end of the experimental period, 7 DPI. Hepatic zinc content was measured by atomic absorption spectroscopy and was found to decrease at 1 and 3 DPI but returned to normal by 7DPI. Zinc in the livers of MT-I/II−/− mice did not show a return to normal at 7 DPI which suggests that after brain injury, MT-I/II is responsible for sequestering elevated levels of zinc to the liver. Conclusion: MT-I/II is up-regulated in the liver after brain injury and modulates the amount of zinc that is sequestered to the liver. PMID:22363575

  7. The peripheral-type benzodiazepine receptor is involved in control of Ca2+-induced permeability transition pore opening in rat brain mitochondria.

    PubMed

    Azarashvili, Tamara; Grachev, Dmitry; Krestinina, Olga; Evtodienko, Youri; Yurkov, Igor; Papadopoulos, Vassilios; Reiser, Georg

    2007-07-01

    The peripheral-type benzodiazepine receptor (PBR) is an 18 kDa mitochondrial membrane protein with still elusive function in cell death. Here, we studied whether PBR is involved in Ca2+-induced permeability transition pore (PTP) opening in isolated rat brain mitochondria (RBM). PTP opening is important in mitochondrial events leading to programmed cell death. Immunoblots revealed a single 18 kDa anti-PBR antibody-immunoreactive band in purified RBM. Adenine nucleotide transporter, a key PTP component, was found in the PBR-immunoprecipitate. In isolated intact RBM, addition of a specific anti-PBR antibody [H. Li, Z. Yao, B. Degenhardt, G. Teper, V. Papadopoulos, Cholesterol binding at the cholesterol recognition/interaction amino acid consensus (CRAC) of the peripheral-type benzodiazepine receptor and inhibition of steroidogenesis by an HIV TAT-CRAC peptide, Proc. Natl. Acad. Sci. U.S.A. 98 (2001) 1267-1272] delayed Ca2+-induced dissipation of membrane potential (psi(m)) and diminished cyclosporine A-sensitive Ca2+ efflux, which are both indicative for the suppression of PTP opening. Moreover, anti-PBR antibody caused partial retention of Ca2+ in the mitochondrial matrix in spite of psi(m) dissipation, and reduced activation of respiratory rate at Ca2+-induced PTP opening. A release of pro-apoptotic factors, AIF and cytochrome c, from RBM was shown at threshold Ca2+ load. Anti-PBR antibody blocked the release of AIF but did not affect the cytochrome c release. Addition of ATP was able to initiate PTP closing, associated with psi(m) restoration and Ca2+ re-accumulation. At the same time mitochondrial protein phosphorylation (incorporation of 32P from [gamma-32P]ATP) occurred and anti-PBR antibody was able to inhibit phosphorylation of these proteins. The endogenous PBR ligand, protoporphyrin IX, facilitated PTP opening and phosphorylation of the mitochondrial proteins, thus, inducing effects opposite to anti-PBR antibody. This study provides evidence for PBR

  8. Dietary alpha-linolenic acid increases brain but not heart and liver docosahexaenoic acid levels.

    PubMed

    Barceló-Coblijn, Gwendolyn; Collison, Lauren W; Jolly, Christopher A; Murphy, Eric J

    2005-08-01

    Fish oil-enriched diets increase n-3 FA in tissue phospholipids; however, a similar effect by plant-derived n-3 FA is poorly defined. To address this question, we determined mass changes in phospholipid FA, individual phospholipid classes, and cholesterol in the liver, heart, and brain of rats fed diets enriched in flax oil (rich in 18:3n-3), fish oil (rich in 22:6n-3 and 20:5n-3), or safflower oil (rich in 18:2n-6) for 8 wk. In the heart and liver phospholipids, 22:6n-3 levels increased only in the fish oil group, although rats fed flax oil accumulated 20:5n-3 and 22:5n-3. However, in the brain, the flax and fish oil diets increased the phospholipid 22:6n-3 mass. In all tissues, these diets decreased the 20:4n-6 mass, although the effect was more marked in the fish oil than in the flax oil group. Although these data do not provide direct evidence for 18:3n-3 elongation and desaturation by the brain, they demonstrate that 18:3n-3-enriched diets reduced tissue 20:4n-6 levels and increased cellular n-3 levels in a tissue-dependent manner. We hypothesize, based on the lack of increased 22:6n-3 but increased 18:3n-3 in the liver and heart, that the flax oil diet increased circulating 18:3n-3, thereby presenting tissue with this EFA for further elongation and desaturation. PMID:16296397

  9. The antiestrogen endoxifen protects rat liver mitochondria from permeability transition pore opening and oxidative stress at concentrations that do not affect the phosphorylation efficiency

    SciTech Connect

    Ribeiro, Mariana P.C.; Silva, Filomena S.G.; Santos, Armanda E.; Santos, Maria S.; Custódio, José B.A.

    2013-02-15

    Endoxifen (EDX) is a key active metabolite of tamoxifen (TAM) with higher affinity and specificity to estrogen receptors that also inhibits aromatase activity. It is safe and well tolerated by healthy humans, but its use requires toxicological characterization. In this study, the effects of EDX on mitochondria, the primary targets for xenobiotic-induced toxicity, were monitored to clarify its potential side effects. EDX up to 30 nmol/mg protein did not affect the mitochondrial oxidative phosphorylation. At 50 nmol EDX/mg protein, EDX decreased the ADP phosphorylation rate and a partial collapse of mitochondrial membrane potential (Δψ), that parallels a state 4 stimulation, was observed. As the stimulation of state 4 was not inhibited by oligomycin and 50 nmol EDX/mg protein caused a slight decrease in the light scattering of mitochondria, these data suggest that EDX promotes membrane permeabilization to protons, whereas TAM at the same concentration induced mitochondrial membrane disruption. Moreover, EDX at 10 nmol/mg protein prevented and reversed the Ca{sup 2+}-induced depolarization of ΔΨ and the release of mitochondrial Ca{sup 2+}, similarly to cyclosporine A, indicating that EDX did not affect Ca{sup 2+} uptake, but directly interfered with the proteins of the mitochondrial permeability transition (MPT) megacomplex, inhibiting MPT induction. At this concentration, EDX exhibited antioxidant activity that may account for the protective effect against MPT pore opening. In conclusion, EDX within the range of concentrations reached in tissues did not significantly damage the bioenergetic functions of mitochondria, contrarily to the prodrug TAM, and prevented the MPT pore opening and the oxidative stress in mitochondria, supporting that EDX may be a less toxic drug for women with breast carcinoma. - Highlights: ► Mitochondria are important targets of Endoxifen. ► Endoxifen prevents mitochondrial permeability transition. ► Endoxifen prevents oxidative

  10. Acute liver failure-induced death of rats is delayed or prevented by blocking NMDA receptors in brain.

    PubMed

    Cauli, Omar; Rodrigo, Regina; Boix, Jordi; Piedrafita, Blanca; Agusti, Ana; Felipo, Vicente

    2008-09-01

    Developing procedures to delay the mechanisms of acute liver failure-induced death would increase patients' survival by allowing time for liver regeneration or to receive a liver for transplantation. Hyperammonemia is a main contributor to brain herniation and mortality in acute liver failure (ALF). Acute ammonia intoxication in rats leads to N-methyl-D-aspartate (NMDA) receptor activation in brain. Blocking these receptors prevents ammonia-induced death. Ammonia-induced activation of NMDA receptors could contribute to ALF-induced death. If this were the case, blocking NMDA receptors could prevent or delay ALF-induced death. The aim of this work was to assess 1) whether ALF leads to NMDA receptors activation in brain in vivo and 2) whether blocking NMDA receptors prevents or delays ALF-induced death of rats. It is shown, by in vivo brain microdialysis, that galactosamine-induced ALF leads to NMDA receptors activation in brain. Blocking NMDA receptors by continuous administration of MK-801 or memantine through miniosmotic pumps affords significant protection against ALF-induced death, increasing the survival time approximately twofold. Also, when liver injury is not 100% lethal (1.5 g/kg galactosamine), blocking NMDA receptors increases the survival rate from 23 to 62%. This supports that blocking NMDA receptors could have therapeutic utility to improve survival of patients with ALF. PMID:18599589