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Brain Research Apr 2010Patients affected by maple syrup urine disease (MSUD) present severe neurological symptoms and brain abnormalities, whose pathophysiology is poorly known. In the present...
Patients affected by maple syrup urine disease (MSUD) present severe neurological symptoms and brain abnormalities, whose pathophysiology is poorly known. In the present study we investigated the in vitro effects of leucine (Leu), alpha-ketoisocaproic acid (KIC) and alpha-hydroxyisovaleric acid (HIV), respectively, the branched-chain amino, keto and hydroxy acids that most accumulate in MSUD, on brain bioenergetic homeostasis, evaluating respiratory parameters obtained by oxygen consumption, membrane potential (Psim), NAD(P)H content, swelling and citric acid cycle enzyme activities in mitochondrial preparations from rat forebrain using glutamate plus malate, succinate or alpha-ketoglutarate as respiratory substrates. KIC increased state 4 and decreased the respiratory control ratio with all substrates, in contrast with Leu and HIV. Furthermore, KIC and Leu, but not HIV, decreased state 3 using alpha-ketoglutarate. A KIC-induced selective inhibition of alpha-ketoglutarate dehydrogenase activity was also verified, with no alteration of the other citric acid cycle activities. The ADP/O ratio and the mitochondrial NAD(P)H levels were also reduced by KIC using glutamate/malate and alpha-ketoglutarate. In addition, KIC caused a reduction in the Psim when alpha-ketoglutarate was the substrate. Finally, KIC was not able to induce mitochondrial swelling. The present data indicate that KIC acts as an uncoupler of oxidative phosphorylation and as a metabolic inhibitor possibly through its inhibitory effect on alpha-ketoglutarate dehydrogenase activity, while Leu acts as a metabolic inhibitor. It is suggested that impairment of mitochondrial homeostasis caused by the major metabolites accumulating in MSUD may be involved in the neuropathology of this disease.
Topics: Animals; Brain; Central Nervous System Agents; Electron Transport; Homeostasis; Keto Acids; Ketoglutarate Dehydrogenase Complex; Leucine; Maple Syrup Urine Disease; Membrane Potential, Mitochondrial; Mitochondrial Diseases; Mitochondrial Swelling; NADP; Oxygen Consumption; Prosencephalon; Rats; Rats, Wistar; Valerates
PubMed: 20153737
DOI: 10.1016/j.brainres.2010.02.018 -
The Journal of Toxicological Sciences 2017The herb Ephedra sinica (also known as Chinese ephedra or Ma Huang), used in traditional Chinese medicine, contains alkaloids identical to ephedrine and pseudoephedrine...
The herb Ephedra sinica (also known as Chinese ephedra or Ma Huang), used in traditional Chinese medicine, contains alkaloids identical to ephedrine and pseudoephedrine as its principal active constituents. Recent studies have reported that ephedrine has various side effects in the cardiovascular and nervous systems. In addition, herbal Ephedra, a plant containing many pharmacologically active alkaloids, principally ephedrine, has been reported to cause acute hepatitis. Many studies reported clinical cases, however, the cellular mechanism of liver toxicity by ephedrine remains unknown. In this study, we investigated hepatotoxicity and key regulation of mitophagy in ephedrine-treated LX-2 cells. Ephedrine triggered mitochondrial oxidative stress and depolarization. Mitochondrial swelling and autolysosome were observed in ephedrine-treated cells. Ephedrine also inhibited mitochondrial biogenesis, and the mitochondrial copy number was decreased. Parkin siRNA recovered the ephedrine-induced mitochondrial damage. Excessive mitophagy lead to cell death through imbalance of autophagic flux. Moreover, antioxidants and reducing Parkin level could serve as therapeutic targets for ephedrine-induced hepatotoxicity.
Topics: Antioxidants; Autophagy; Cell Death; Cells, Cultured; Chemical and Drug Induced Liver Injury; Ephedra sinica; Ephedrine; Gene Dosage; Hepatic Stellate Cells; Humans; Lysosomes; Mitochondria, Liver; Mitochondrial Swelling; Mitophagy; Molecular Targeted Therapy; Organelle Biogenesis; Oxidative Stress; RNA, Small Interfering; Ubiquitin-Protein Ligases
PubMed: 28717105
DOI: 10.2131/jts.42.461 -
Yakugaku Zasshi : Journal of the... 2013Cardiolipin (CL) is a phospholipid, which is exclusively located in mitochondria, and has a unique structure that consists of 2 phosphate residues and 4 kinds of fatty... (Review)
Review
Cardiolipin (CL) is a phospholipid, which is exclusively located in mitochondria, and has a unique structure that consists of 2 phosphate residues and 4 kinds of fatty acyl chains. Cardiolipin plays an important role in regulating various kinds of mitochondrial proteins such as electron transport complexes, carrier proteins and phosphate kinases, and is also essential for the organization of particular mitochondrial structures such as cristae and contact sites. Mitochondrial phospholipase D hydrolyzes CL to produce phosphatidic acid, which is required for mitochondrial fusion. Oxidative stress-induced peroxidation of CL occurs because CL is rich in polyunsaturated fatty acids, especially linoleic acid. Accumulation of CL hydroperoxide (CLOOH) triggers the initiation of apoptosis. Formation of CLOOH causes the release of proapoptotic factors such as cytochrome c from the inner mitochondrial membrane and triggers opening of the permeability transition pore. Levels of CL decrease in the heart following ischemia or disease. Apoptosis is enhanced in temperature-dependent mutant cells whose amounts of CL reduce to half when compared to that of wild type cells. Low levels of CL cause the accumulation of CLOOH and enhance sensitivity to apoptosis. Accumulation of CLOOH in mitochondria causes instability of the membrane, because swelling of mitochondria is induced by the presence of CLOOH in the membrane and is significantly enhanced in CLOOH-loaded mitochondria by the addition of inducer of swelling.
Topics: Animals; Apoptosis; Cardiolipins; Cytochromes c; Drosophila Proteins; Humans; Linoleic Acid; Lipid Peroxidation; Lipid Peroxides; Mitochondria; Mitochondrial Dynamics; Mitochondrial Proteins; Mitochondrial Swelling; Oxidative Stress; Phosphatidic Acids; Phospholipase D; Ubiquitin-Protein Ligases
PubMed: 23649397
DOI: 10.1248/yakushi.13-00052 -
Biochimica Et Biophysica Acta.... Jan 2019The paper considers the effects of bedaquiline (BDQ), an antituberculous preparation of the new generation, on rat liver mitochondria. It was shown that 50 μM BDQ...
The paper considers the effects of bedaquiline (BDQ), an antituberculous preparation of the new generation, on rat liver mitochondria. It was shown that 50 μM BDQ inhibited mitochondrial respiration measured with substrates of complexes I and II (glutamate/malate and succinate/rotenone systems respectively) in the states V and V. At the same time, at concentrations below 50 μM, BDQ slightly stimulated respiration with substrates of complex I in the state V. BDQ was also found to suppress, in a dose-dependent manner, the activity of complex II and the total activity of complexes II + III of the mitochondrial transport chain. It was discovered that at concentrations up to 10 μM, BDQ inhibited HO production in mitochondria. BDQ (10-50 μM) suppressed the opening of Ca-dependent CsA-sensitive mitochondrial permeability transition pore. The latter was revealed experimentally as the inhibition of Ca/P-dependent swelling of mitochondria, suppression of cytochrome c release, and an increase in the Ca capacity of the organelles. BDQ also decreased the rate of mitochondrial energy-dependent K transport, which was evaluated by the energy-dependent swelling of mitochondria in a K buffer and DNP-induced K efflux from the organelles. The possible mechanisms of BDQ effect of rat liver mitochondria are discussed.
Topics: Animals; Antitubercular Agents; Cyclosporine; Cytochromes c; Diarylquinolines; Electron Transport; Glutamic Acid; Hydrogen Peroxide; Malates; Membrane Potential, Mitochondrial; Mitochondria; Mitochondria, Liver; Mitochondrial Membrane Transport Proteins; Mitochondrial Membranes; Mitochondrial Permeability Transition Pore; Mitochondrial Swelling; Oxygen Consumption; Permeability; Potassium; Rats; Rats, Wistar; Rotenone; Succinic Acid
PubMed: 29920239
DOI: 10.1016/j.bbamem.2018.06.012 -
BMC Microbiology Sep 2013Naphthoquinones (NQs) are privileged structures in medicinal chemistry due to the biological effects associated with the induction of oxidative stress. The present study...
BACKGROUND
Naphthoquinones (NQs) are privileged structures in medicinal chemistry due to the biological effects associated with the induction of oxidative stress. The present study evaluated the activities of sixteen NQs derivatives on Trypanosoma cruzi.
RESULTS
Fourteen NQs displayed higher activity against bloodstream trypomastigotes of T. cruzi than benznidazole. Further assays with NQ1, NQ8, NQ9 and NQ12 showed inhibition of the proliferation of axenic epimastigotes and intracelulluar amastigotes interiorized in macrophages and in heart muscle cells. NQ8 was the most active NQ against both proliferative forms of T. cruzi. In epimastigotes the four NQs induced mitochondrial swelling, vacuolization, and flagellar blebbing. The treatment with NQs also induced the appearance of large endoplasmic reticulum profiles surrounding different cellular structures and of myelin-like membranous contours, morphological characteristics of an autophagic process. At IC50 concentration, NQ8 totally disrupted the ΔΨm of about 20% of the parasites, suggesting the induction of a sub-population with metabolically inactive mitochondria. On the other hand, NQ1, NQ9 or NQ12 led only to a discrete decrease of TMRE + labeling at IC50 values. NQ8 led also to an increase in the percentage of parasites labeled with DHE, indicative of ROS production, possibly the cause of the observed mitochondrial swelling. The other three NQs behaved similarly to untreated controls.
CONCLUSIONS
NQ1, NQ8, NQ9 and NQ12 induce an autophagic phenotype in T. cruzi epimastigoted, as already observed with others NQs. The absence of oxidative stress in NQ1-, NQ9- and NQ12-treated parasites could be due to the existence of more than one mechanism of action involved in their trypanocidal activity, leaving ROS generation suppressed by the detoxification system of the parasite. The strong redox effect of NQ8 could be associated to the presence of the acetyl group in its structure facilitating quinone reduction, as previously demonstrated by electrochemical analysis. Further experiments using biochemical and molecular approaches are needed to better characterize ROS participation in the mechanism of action of these NQs.
Topics: Animals; Antiprotozoal Agents; Inhibitory Concentration 50; Macrophages; Membrane Potential, Mitochondrial; Mice; Mitochondria; Mitochondrial Swelling; Naphthoquinones; Parasitic Sensitivity Tests; Trypanosoma cruzi
PubMed: 24004461
DOI: 10.1186/1471-2180-13-196 -
The Biochemical Journal Sep 19871. The matrix pyrophosphate (PPi) content of isolated energized rat liver mitochondria incubated in the presence of ATP, Mg2+, Pi and respiratory substrate was about 100...
1. The matrix pyrophosphate (PPi) content of isolated energized rat liver mitochondria incubated in the presence of ATP, Mg2+, Pi and respiratory substrate was about 100 pmol/mg of protein. 2. After incubation with sub-micromolar [Ca2+], this was increased by as much as 300%. There was a correlation between the effects of Ca2+ on PPi and on the increase in matrix volume reported previously [Halestrap, Quinlan, Whipps & Armston (1986) Biochem. J. 236, 779-787]. Half-maximal effects were seen at 0.3 microM-Ca2+. 3. Coincident with these effects, the total adenine nucleotide content increased in a carboxyatractyloside-sensitive manner. 4. Incubation with 0.2-0.5 mM-butyrate induced similar but smaller effects on mitochondrial swelling and matrix PPi and total adenine nucleotide content. Addition of butyrate after Ca2+, or vice versa, caused Ca2+-induced mitochondrial swelling to stop or reverse, while matrix PPi increased 30-fold. 5. Addition of atractyloside or the omission of ATP from incubations greatly enhanced swelling induced by Ca2+ without increasing matrix PPi. 6. Swelling of mitochondria incubated under de-energized conditions in iso-osmotic KSCN was progressively enhanced by the addition of increasing concentrations of PPi (1-20 mM) or valinomycin. 7. In iso-osmotic potassium pyrophosphate swelling was slow initially, but accelerated with time. This acceleration was inhibited by ADP, whereas carboxyatractyloside induced rapid swelling. Swelling in other iso-osmotic PPi salts showed that the rate of entry decreased in the order NH4+ greater than K+ greater than Na+ greater than Li+, whereas choline, tetramethylammonium and Tris did not enter. It is suggested that the adenine nucleotide translocase transports small univalent cations when PPi is bound and that PPi can also be transported when the transporter is in the conformation induced by carboxyatractyloside. 8. It is concluded that Ca2+ and butyrate cause swelling of energized mitochondria through this effect of PPi on K+ permeability of the mitochondrial inner membrane. 9. Freeze-clamped livers from rats treated with glucagon or phenylephrine show 30-50% increases in tissue PPi. It is proposed that Ca2+-mediated increases in mitochondrial PPi are responsible for the increase in matrix volume and total adenine nucleotide content observed after hormone treatment.
Topics: Adenine Nucleotides; Adenosine Triphosphate; Animals; Atractyloside; Butyrates; Butyric Acid; Calcium; Diphosphates; Female; Light; Mitochondria, Liver; Mitochondrial ADP, ATP Translocases; Mitochondrial Swelling; Rats; Rats, Inbred Strains; Scattering, Radiation
PubMed: 2825649
DOI: 10.1042/bj2460715 -
The Journal of Biological Chemistry Dec 1984Heart mitochondria depleted of endogenous divalent cations by treatment with A23187 and EDTA swell in (a) K+ acetate or (b) K+ nitrate when an uncoupler is present....
Heart mitochondria depleted of endogenous divalent cations by treatment with A23187 and EDTA swell in (a) K+ acetate or (b) K+ nitrate when an uncoupler is present. These mitochondria also exchange matrix 42K+ with external K+, Na+, or Li+ in a reaction that does not require respiration and is insensitive to uncouplers. Untreated control mitochondria do not swell in either medium nor do they show the passive cation exchange. Both the swelling and the exchange reactions are inhibited by Mg2+ and by quinine and other lipophilic amines. Swelling and exchange are both strongly activated at alkaline pH, and the exchange reaction is also increased markedly by hypotonic conditions. All of these properties correspond to those reported for a respiration-dependent extrusion of K+ from Mg2+-depleted mitochondria, a reaction attributed to a latent Mg2+- and H+-sensitive K+/H+ antiport. The swelling reactions are strongly inhibited by dicyclohexylcarbodiimide reacted under hypotonic conditions, but the exchange reaction is not sensitive to this reagent. Heart mitochondria depleted of Mg2+ show marked increases in their permeability to H+, to anions, and possibly to cations, and the permeability to each of these components is further increased at alkaline pH. This generalized increase in membrane permeability makes it likely that K+/H+ antiport is not the only pathway available for K+ movement in these mitochondria. It is concluded that the swelling, 42K+ exchange, and K+ extrusion data are all consistent with the presence of the putative K+/H+ antiport but that definitive evidence for the participation of such a component in these reactions is still lacking.
Topics: Animals; Calcimycin; Carbonyl Cyanide m-Chlorophenyl Hydrazone; Carrier Proteins; Cations, Divalent; Cattle; Dicyclohexylcarbodiimide; Edetic Acid; Kinetics; Mitochondria, Heart; Mitochondrial Swelling; Potassium; Potassium-Hydrogen Antiporters
PubMed: 6438102
DOI: No ID Found -
Biological Research Mar 2016Despite manifold benefits of nanoparticles (NPs), less information on the risks of NPs to human health and environment has been studied. Cobalt oxide nanoparticles...
BACKGROUND
Despite manifold benefits of nanoparticles (NPs), less information on the risks of NPs to human health and environment has been studied. Cobalt oxide nanoparticles (Co3O4-NPs) have been reported to cause toxicity in several organisms. In this study, we have investigated the role of Co3O4-NPs in inducing phytotoxicity, cellular DNA damage and apoptosis in eggplant (Solanum melongena L. cv. Violetta lunga 2). To the best of our knowledge, this is the first report on Co3O4-NPs showing phytotoxicity in eggplant.
RESULTS
The data revealed that eggplant seeds treated with Co3O4-NPs for 2 h at a concentration of 1.0 mg/ml retarded root length by 81.5 % upon 7 days incubation in a moist chamber. Ultrastructural analysis by transmission electron microscopy (TEM) demonstrated the uptake and translocation of Co3O4-NPs into the cytoplasm. Intracellular presence of Co3O4-NPs triggered subcellular changes such as degeneration of mitochondrial cristae, abundance of peroxisomes and excessive vacuolization. Flow cytometric analysis of Co3O4-NPs (1.0 mg/ml) treated root protoplasts revealed 157, 282 and 178 % increase in reactive oxygen species (ROS), membrane potential (ΔΨm) and nitric oxide (NO), respectively. Besides, the esterase activity in treated protoplasts was also found compromised. About 2.4-fold greater level of DNA damage, as compared to untreated control was observed in Comet assay, and 73.2 % of Co3O4-NPs treated cells appeared apoptotic in flow cytometry based cell cycle analysis.
CONCLUSION
This study demonstrate the phytotoxic potential of Co3O4-NPs in terms of reduction in seed germination, root growth, greater level of DNA and mitochondrial damage, oxidative stress and cell death in eggplant. The data generated from this study will provide a strong background to draw attention on Co3O4-NPs environmental hazards to vegetable crops.
Topics: Analysis of Variance; Cell Death; Cobalt; Comet Assay; DNA Damage; Flow Cytometry; Microscopy, Electron, Transmission; Mitochondrial Swelling; Nanoparticles; Nitric Oxide; Oxides; Reactive Oxygen Species; Solanum melongena
PubMed: 26988690
DOI: 10.1186/s40659-016-0080-9 -
Biochemical and Biophysical Research... Oct 2019Noxa is a weak apoptosis activator consisting of a BH3 domain and a mitochondrial-targeting domain (MTD). BH3 binds Mcl-1 and Bcl2A1 and inactivates their anti-apoptotic...
Noxa is a weak apoptosis activator consisting of a BH3 domain and a mitochondrial-targeting domain (MTD). BH3 binds Mcl-1 and Bcl2A1 and inactivates their anti-apoptotic activities, while MTD delivers BH3 to mitochondria. Previously we revealed that MTD may also function as an inducer of necrosis via conjugation with octa-arginine, which induces cytosolic Ca influx from mitochondria. However, the mechanism(s) underlying this process has not been elucidated yet. Here, we show that calcium influx induced by an MTD peptide fused with octa-arginine residue (R8:MTD) originates not only from mitochondria but also from the extracellular space. However, calcium spikes were not sufficient for necrosis. R8:MTD induced mitochondrial permeability transition pore opening, fragmentation, and swelling. These mitochondrial events induced by MTD appeared to be necessary for necrosis induction, since DIDS, a VDAC inhibitor, inhibited the mitochondrial swelling and cell death induced by MTD. We show that R8:MTD disrupted endoplasmic reticulum (ER) structures but not peroxisomes or Golgi, indicating that R8:MTD causes necrosis by inducing ER events as well.
Topics: 4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid; Calcium; Cell Death; Cytosol; Endoplasmic Reticulum; Extracellular Space; HeLa Cells; Humans; Mitochondria; Mitochondrial Membrane Transport Proteins; Mitochondrial Permeability Transition Pore; Mitochondrial Swelling; Peptides; Protein Domains; Proto-Oncogene Proteins c-bcl-2; Voltage-Dependent Anion Channels
PubMed: 31421829
DOI: 10.1016/j.bbrc.2019.08.011 -
Cytometry. Part a : the Journal of the... Jan 2006Understanding the interdependence of mitochondrial and cellular functioning in health and disease requires detailed knowledge about the coupling between mitochondrial...
BACKGROUND
Understanding the interdependence of mitochondrial and cellular functioning in health and disease requires detailed knowledge about the coupling between mitochondrial structure, motility, and function. Currently, no rapid approach is available for simultaneous quantification of these parameters in single living cells.
METHODS
Human skin fibroblasts were pulse-loaded with the mitochondria-selective fluorescent cation rhodamine 123. Next, mitochondria were visualized using video-rate (30 Hz) confocal microscopy and real-time image averaging. To highlight the mitochondria, the acquired images were binarized using a novel image processing strategy.
RESULTS
Our approach enabled rapid and simultaneous quantification of mitochondrial morphology, mass, potential, and motility. It was found that acute inhibition of mitochondrial complex I (NADH:ubiquinone oxidoreductase) by means of rotenone transiently reduced mitochondrial branching, area, and potential. In contrast, mitochondrial motility was permanently reduced.
CONCLUSIONS
We present and validate a novel approach for rapid, unbiased, and simultaneous quantification of multiple mitochondrial parameters in living cells. Because this method is automated, large numbers of cells can be analyzed in a short period of time.
Topics: Cells, Cultured; Electron Transport Complex I; Fibroblasts; Fluorescent Dyes; Humans; Membrane Potentials; Microscopy, Confocal; Mitochondria; Mitochondrial Membranes; Mitochondrial Swelling; NAD; Rhodamines; Rotenone; Skin
PubMed: 16342116
DOI: 10.1002/cyto.a.20198