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Biochimica Et Biophysica Acta 2010Mitochondria generated nitric oxide (NO) regulates several cell functions including energy metabolism, cell cycling, and cell death. Here we report that the NO synthase...
Mitochondria generated nitric oxide (NO) regulates several cell functions including energy metabolism, cell cycling, and cell death. Here we report that the NO synthase inhibitors (L-NAME, L-NNA and L-NMMA) administered either in vitro or in vivo induce Ca2+-dependent mitochondrial permeability transition (MPT) in rat liver mitochondria via a mechanism independent on changes in the energy state of the organelle. MPT was determined by the occurrence of cyclosporin A sensitive mitochondrial membrane potential disruption followed by mitochondrial swelling and Ca2+ release. In in vitro experiments, the effect of NOS inhibitors was dose-dependent (1 to 50 microM). In addition to cyclosporin A, L-NAME-induced MPT was sensitive to Mg2+ plus ATP, EGTA, and to a lower degree, to catalase and dithiothreitol. In contrast to L-NAME, its isomer D-NAME did not induce MPT. L-NAME-induced MPT was associated with a significant decrease in both the rate of NO generation and the content of mitochondrial S-nitrosothiol. Acute and chronic in vivo treatment with L-NAME also promoted MPT and decreased the content of mitochondrial S-nitrosothiol. SNAP (a NO donor) prevented L-NAME mediated MPT and reversed the decrease in the rate of NO generation and in the content of S-nitrosothiol. We propose that S-nitrosylation of critical membrane protein thiols by NO protects against MPT.
Topics: Animals; Enzyme Inhibitors; Female; In Vitro Techniques; Membrane Potential, Mitochondrial; Mitochondria, Liver; Mitochondrial Membrane Transport Proteins; Mitochondrial Permeability Transition Pore; Mitochondrial Swelling; NG-Nitroarginine Methyl Ester; Nitric Oxide; Nitric Oxide Donors; Nitric Oxide Synthase; Rats; Rats, Wistar; S-Nitroso-N-Acetylpenicillamine; S-Nitrosothiols
PubMed: 20138021
DOI: 10.1016/j.bbabio.2010.01.034 -
Toxicology Letters Aug 2012Acetaminophen (APAP) overdose leads to severe hepatotoxicity, increased oxidative stress and mitochondrial dysfunction. S-adenosyl-L-methionine (SAMe) protects against...
Acetaminophen (APAP) overdose leads to severe hepatotoxicity, increased oxidative stress and mitochondrial dysfunction. S-adenosyl-L-methionine (SAMe) protects against APAP toxicity at a mmol/kg equivalent dose to N-acetylcysteine (NAC). SAMe acts as a principle biological methyl donor and participates in polyamine synthesis which increase cell growth and has a role in mitochondrial protection. The purpose of the current study tested the hypothesis that SAMe protects against APAP toxicity by maintaining critical antioxidant enzymes and markers of oxidative stress. Male C57Bl/6 mice were treated with vehicle (Veh; water 15 ml/kg, ip), SAMe (1.25 mmol/kg, ip), APAP (250 mg/kg, ip), and SAMe+APAP (SAMe given 1 h following APAP). Liver was collected 2 and 4 h following APAP administration; mitochondrial swelling as well as hepatic catalase, glutathione peroxidase (GPx), glutathione reductase, and both Mn- and Cu/Zn-superoxide dismutase (SOD) enzyme activity were evaluated. Mitochondrial protein carbonyl, 3-nitrotyrosine cytochrome c leakage were analyzed by Western blot. SAMe significantly increased SOD, GPx, and glutathione reductase activity at 4 h following APAP overdose. SAMe greatly reduced markers of oxidative stress and cytochrome C leakage following APAP overdose. Our studies also demonstrate that a 1.25 mmol/kg dose of SAMe does not inhibit CYP 2E1 enzyme activity. The current study identifies a plausible mechanism for the decreased oxidative stress observed when SAMe is given following APAP.
Topics: Acetaminophen; Alanine Transaminase; Analgesics, Non-Narcotic; Animals; Chemical and Drug Induced Liver Injury; Cytochrome P-450 CYP2E1; Cytochrome P-450 CYP2E1 Inhibitors; Drug Antagonism; Liver; Male; Mice; Mice, Inbred C57BL; Mitochondria, Liver; Mitochondrial Swelling; Oxidative Stress; Oxidoreductases; Protein Carbonylation; S-Adenosylmethionine
PubMed: 22683606
DOI: 10.1016/j.toxlet.2012.05.018 -
The Journal of Neuroscience : the... Jan 2000Isolated brain mitochondria were examined for their responses to calcium challenges under varying conditions. Mitochondrial membrane potential was monitored by following...
Isolated brain mitochondria were examined for their responses to calcium challenges under varying conditions. Mitochondrial membrane potential was monitored by following the distribution of tetraphenylphosphonium ions in the mitochondrial suspension, mitochondrial swelling by observing absorbance changes, calcium accumulation by an external calcium electrode, and oxygen consumption with an oxygen electrode. Both the extent and rate of calcium-induced mitochondrial swelling and depolarization varied greatly depending on the energy source provided to the mitochondria. When energized with succinate plus glutamate, after a calcium challenge, CNS mitochondria depolarized transiently, accumulated substantial calcium, and increased in volume, characteristic of a mitochondrial permeability transition. When energized with 3 mM succinate, CNS mitochondria maintained a sustained calcium-induced depolarization without appreciable swelling and were slow to accumulate calcium. Maximal oxygen consumption was also restricted under these conditions, preventing the electron transport chain from compensating for this increased proton permeability. In 3 mM succinate, cyclosporin A and ADP plus oligomycin restored potential and calcium uptake. This low conductance permeability was not effected by bongkrekic acid or carboxyatractylate, suggesting that the adenine nucleotide translocator was not directly involved. Fura-2FF measurements of [Ca(2+)](i) suggest that in cultured hippocampal neurons glutamate-induced increases reached tens of micromolar levels, approaching those used with mitochondria. We propose that in the restricted substrate environment, Ca(2+) activated a low-conductance permeability pathway responsible for the sustained mitochondrial depolarization.
Topics: Adenosine Diphosphate; Animals; Antineoplastic Agents; Atractyloside; Brain; Calcium; Electric Conductivity; Fluorescent Dyes; Fura-2; Glutamic Acid; Membrane Potentials; Mitochondria; Mitochondrial Swelling; Nerve Degeneration; Oligomycins; Onium Compounds; Organophosphorus Compounds; Oxidation-Reduction; Oxygen Consumption; Rats; Strontium; Succinic Acid; Uncoupling Agents
PubMed: 10627586
DOI: 10.1523/JNEUROSCI.20-01-00103.2000 -
American Journal of Physiology.... Nov 2004The mitochondrial mass of rat brain and liver remained unchanged on aging in young adults, old adults, and senescent animals (28, 60, and 92 wk of age); the values were...
The mitochondrial mass of rat brain and liver remained unchanged on aging in young adults, old adults, and senescent animals (28, 60, and 92 wk of age); the values were 15-17 and 29-31 mg protein/g for brain and liver, respectively. The whole aging process was associated with an increased content of the oxidation products, thiobarbituric acid-reactive substances and protein carbonyls, by 61-69% in brain and 36-45% in liver, respectively. The activities of critical enzymes for mitochondrial function, mitochondrial nitric oxide synthase, Mn-superoxide dismutase, complex I, and complex IV, decreased progressively during aging with activity losses of 73, 37, 29, and 28%, respectively, in the brain and 47, 46, 30, and 24% in the liver of senescent rats compared with young adults. Brain mitochondria isolated from aged rats showed increased mitochondrial fragility, as assayed by mitochondrial marker enzyme activities in the postmitochondrial supernatant, and increased volume and water permeability, as assayed by light scattering. Liver mitochondria isolated from young and old rats did not show differences in fragility and water permeability. A subpopulation of brain mitochondria with increased size and fragility was differentiated in aging rats, whereas liver showed a homogeneous mitochondrial population.
Topics: Aging; Animals; Biomarkers; Brain; Brain Chemistry; Electron Transport; Light; Male; Mitochondria; Mitochondria, Liver; Mitochondrial Swelling; NADH Dehydrogenase; Nitric Oxide Synthase; Oxidative Stress; Permeability; Rats; Scattering, Radiation; Superoxide Dismutase
PubMed: 15271654
DOI: 10.1152/ajpregu.00226.2004 -
Journal of Bioenergetics and... Aug 2005Mitochondria contribute to cytosolic Ca(2+) homeostasis through several uptake and release pathways. Here we report that 1,2-sn-diacylglycerols (DAG's) induce Ca(2+)...
Mitochondria contribute to cytosolic Ca(2+) homeostasis through several uptake and release pathways. Here we report that 1,2-sn-diacylglycerols (DAG's) induce Ca(2+) release from Ca(2+)-loaded mammalian mitochondria. Release is not mediated by the uni-porter or the Na(+)/Ca(2+) exchanger, nor is it attributed to putative catabolites. DAG's-induced Ca(2+) efflux is biphasic. Initial release is rapid and transient, insensitive to permeability transition inhibitors, and not accompanied by mitochondrial swelling. Following initial rapid release of Ca(2+) and relatively slow reuptake, a secondary progressive release of Ca(2+) occurs, associated with swelling, and mitigated by permeability transition inhibitors. The initial peak of DAG's-induced Ca(2+) efflux is abolished by La(3+) (1 mM) and potentiated by protein kinase C inhibitors. Phorbol esters, 1,3-diacylglycerols and 1-monoacylglycerols do not induce mitochondrial Ca(2+) efflux. Ca(2+)-loaded mitoplasts devoid of outer mitochondrial membrane also exhibit DAG's-induced Ca(2+) release, indicating that this mechanism resides at the inner mitochondrial membrane. Patch clamping brain mitoplasts reveal DAG's-induced slightly cation-selective channel activity that is insensitive to bongkrekic acid and abolished by La(3+). The presence of a second messenger-sensitive Ca(2+) release mechanism in mitochondria could have an important impact on intracellular Ca(2+) homeostasis.
Topics: Animals; Brain; Calcium; Calcium Channel Blockers; Calcium Channels; Diglycerides; Enzyme Activation; Intracellular Membranes; Ion Channels; Ipomoea batatas; Male; Mice; Mitochondria; Mitochondrial Swelling; Protein Kinase C; Rats; Rats, Sprague-Dawley; Sodium-Calcium Exchanger
PubMed: 16167179
DOI: 10.1007/s10863-005-6634-0 -
Journal of Neurochemistry Sep 1999Both reactive dopamine metabolites and mitochondrial dysfunction have been implicated in the neurodegeneration of Parkinson's disease. Dopamine metabolites, dopamine...
Both reactive dopamine metabolites and mitochondrial dysfunction have been implicated in the neurodegeneration of Parkinson's disease. Dopamine metabolites, dopamine quinone and reactive oxygen species, can directly alter protein function by oxidative modifications, and several mitochondrial proteins may be targets of this oxidative damage. In this study, we examined, using isolated brain mitochondria, whether dopamine oxidation products alter mitochondrial function. We found that exposure to dopamine quinone caused a large increase in mitochondrial resting state 4 respiration. This effect was prevented by GSH but not superoxide dismutase and catalase. In contrast, exposure to dopamine and monoamine oxidase-generated hydrogen peroxide resulted in a decrease in active state 3 respiration. This inhibition was prevented by both pargyline and catalase. We also examined the effects of dopamine oxidation products on the opening of the mitochondrial permeability transition pore, which has been implicated in neuronal cell death. Dopamine oxidation to dopamine quinone caused a significant increase in swelling of brain and liver mitochondria. This was inhibited by both the pore inhibitor cyclosporin A and GSH, suggesting that swelling was due to pore opening and related to dopamine quinone formation. In contrast, dopamine and endogenous monoamine oxidase had no effect on mitochondrial swelling. These findings suggest that mitochondrial dysfunction induced by products of dopamine oxidation may be involved in neurodegenerative conditions such as Parkinson's disease and methamphetamine-induced neurotoxicity.
Topics: Animals; Brain; Cell Membrane Permeability; Cyclosporine; Dopamine; In Vitro Techniques; Male; Mitochondria; Mitochondria, Liver; Mitochondrial Swelling; Monoamine Oxidase; Monophenol Monooxygenase; Oxidation-Reduction; Oxygen Consumption; Parkinson Disease; Rats; Rats, Sprague-Dawley
PubMed: 10461904
DOI: 10.1046/j.1471-4159.1999.0731127.x -
Toxicology Letters Oct 2012The objectives of this work were to evaluate the direct effects of diallysulfide (DAS) and diallyldisulfide (DADS), two major organosulfur compounds of garlic oil, on...
The objectives of this work were to evaluate the direct effects of diallysulfide (DAS) and diallyldisulfide (DADS), two major organosulfur compounds of garlic oil, on mitochondrial function and integrity, by using isolated mouse liver mitochondria in a cell-free system. DADS produced concentration-dependent mitochondrial swelling over the range 125-1000μM, while DAS was ineffective. Swelling experiments performed with de-energized or energized mitochondria showed similar maximal swelling amplitudes. Cyclosporin A (1μM), or ethylene glycol-bis(2-aminoethylether)-N,N,N',N'-tetraacetic acid (EGTA, 1mM) were ineffective in inhibiting DADS-induced mitochondrial swelling. DADS produced a minor (12%) decrease in mitochondrial membrane protein thiols, but did not induce clustering of mitochondrial membrane proteins. Incubation of mitochondria with DADS (but not DAS) produced an increase in the oxidation rate of 2',7' dichlorofluorescein diacetate (DCFH-DA), together with depletion of reduced glutathione (GSH) and increased lipid peroxidation. DADS (but not DAS) produced a concentration-dependent dissipation of the mitochondrial membrane potential, but did not induce cytochrome c release. DADS-dependent effects, including mitochondrial swelling, DCFH-DA oxidation, lipid peroxidation and loss of mitochondrial membrane potential, were inhibited by antioxidants and iron chelators. These results suggest that DADS causes direct impairment of mitochondrial function as the result of oxidation of the membrane lipid phase initiated by the GSH- and iron-dependent generation of oxidants.
Topics: Allyl Compounds; Animals; Cell-Free System; Cyclosporine; Cytochromes c; Disulfides; Female; Flow Cytometry; Glutathione; Liver; Membrane Potential, Mitochondrial; Mice; Mitochondria, Liver; Mitochondrial Swelling; Reactive Oxygen Species; Sulfides
PubMed: 22960305
DOI: 10.1016/j.toxlet.2012.08.017 -
PloS One 2016Obesity promotes cardiac and cerebral microcirculatory dysfunction that could be improved by incretin-based therapies. However, the effects of this class of compounds on...
BACKGROUND AND AIMS
Obesity promotes cardiac and cerebral microcirculatory dysfunction that could be improved by incretin-based therapies. However, the effects of this class of compounds on neuro-cardiovascular system damage induced by high fat diet remain unclear. The aim of this study was to investigate the effects of incretin-based therapies on neuro-cardiovascular dysfunction induced by high fat diet in Wistar rats.
METHODS AND RESULTS
We have evaluated fasting glucose levels and insulin resistance, heart rate variability quantified on time and frequency domains, cerebral microcirculation by intravital microscopy, mean arterial blood pressure, ventricular function and mitochondrial swelling. High fat diet worsened biometric and metabolic parameters and promoted deleterious effects on autonomic, myocardial and haemodynamic parameters, decreased capillary diameters and increased functional capillary density in the brain. Biometric and metabolic parameters were better improved by glucagon like peptide-1 (GLP-1) compared with dipeptdyl peptidase-4 (DPP-4) inhibitor. On the other hand, both GLP-1 agonist and DPP-4 inhibitor reversed the deleterious effects of high fat diet on autonomic, myocardial, haemodynamic and cerebral microvascular parameters. GLP-1 agonist and DPP-4 inhibitor therapy also increased mitochondrial permeability transition pore resistance in brain and heart tissues of rats subjected to high fat diet.
CONCLUSION
Incretin-based therapies improve deleterious cardiovascular effects induced by high fat diet and may have important contributions on the interplay between neuro-cardiovascular dynamic controls through mitochondrial dysfunction associated to metabolic disorders.
Topics: Animals; Biometry; Cardiovascular System; Cerebrovascular Circulation; Diet, High-Fat; Energy Intake; Glucose; Heart Rate; Heart Ventricles; Incretins; Male; Microcirculation; Mitochondrial Swelling; Myocardium; Nervous System; Rats, Wistar
PubMed: 26828649
DOI: 10.1371/journal.pone.0148402 -
The Journal of Biological Chemistry Sep 2002Human T-cell leukemia virus type 1 encodes a number of "accessory" proteins of unclear function; one of these proteins, p13(II), is targeted to mitochondria and disrupts...
Human T-cell leukemia virus type 1 encodes a number of "accessory" proteins of unclear function; one of these proteins, p13(II), is targeted to mitochondria and disrupts mitochondrial morphology. The present study was undertaken to unravel the function of p13(II) through (i) determination of its submitochondrial localization and sequences required to alter mitochondrial morphology and (ii) an assessment of the biophysical and biological properties of synthetic peptides spanning residues 9-41 (p13(9-41)), which include the amphipathic mitochondrial-targeting sequence of the protein. p13(9-41) folded into an alpha helix in micellar environments. Fractionation and immunogold labeling indicated that full-length p13(II) accumulates in the inner mitochondrial membrane. p13(9-41) induced energy-dependent swelling of isolated mitochondria by increasing inner membrane permeability to small cations (Na(+), K(+)) and released Ca(2+) from Ca(2+)-preloaded mitochondria. These effects as well as the ability of full-length p13(II) to alter mitochondrial morphology in cells required the presence of four arginines, forming the charged face of the targeting signal. The mitochondrial effects of p13(9-41) were insensitive to cyclosporin A, suggesting that full-length p13(II) might alter mitochondrial permeability through a permeability transition pore-independent mechanism, thus distinguishing it from the mitochondrial proteins Vpr and X of human immunodeficiency virus type 1 and hepatitis B virus, respectively.
Topics: Amino Acid Sequence; Arginine; Human T-lymphotropic virus 1; Humans; Membrane Potentials; Mitochondria; Mitochondrial Swelling; Molecular Sequence Data; Peptide Fragments; Protein Folding; Protein Structure, Secondary; Retroviridae Proteins; Structure-Activity Relationship
PubMed: 12093802
DOI: 10.1074/jbc.M203023200 -
PloS One 2014Mitochondrial dysfunction plays a critical role in the development of cardiac hypertrophy and heart failure. So mitochondria are emerging as one of the important...
Mitochondrial dysfunction plays a critical role in the development of cardiac hypertrophy and heart failure. So mitochondria are emerging as one of the important druggable targets in the management of cardiac hypertrophy and other associated complications. In the present study, effects of ethanolic extract of Boerhaavia diffusa (BDE), a green leafy vegetable against mitochondrial dysfunction in angiotensin II (Ang II) induced hypertrophy in H9c2 cardiomyoblasts was evaluated. H9c2 cells challenged with Ang II exhibited pathological hypertrophic responses and mitochondrial dysfunction which was evident from increment in cell volume (49.09±1.13%), protein content (55.17±1.19%), LDH leakage (58.74±1.87%), increased intracellular ROS production (26.25±0.91%), mitochondrial superoxide generation (65.06±2.27%), alteration in mitochondrial transmembrane potential (ΔΨm), opening of mitochondrial permeability transition pore (mPTP) and mitochondrial swelling. In addition, activities of mitochondrial respiratory chain complexes (I-IV), aconitase, NADPH oxidase, thioredoxin reductase, oxygen consumption rate and calcium homeostasis were evaluated. Treatment with BDE significantly prevented the generation of intracellular ROS and mitochondrial superoxide radicals and protected the mitochondria by preventing dissipation of ΔΨm, opening of mPTP, mitochondrial swelling and enhanced the activities of respiratory chain complexes and oxygen consumption rate in H9c2 cells. Activities of aconitase and thioredoxin reductase which was lowered (33.77±0.68% & 45.81±0.71% respectively) due to hypertrophy, were increased in BDE treated cells (P≤0.05). Moreover, BDE also reduced the intracellular calcium overload in Ang II treated cells. Overall results revealed the protective effects of B. diffusa against mitochondrial dysfunction in hypertrophy in H9c2 cells and the present findings may shed new light on the therapeutic potential of B. diffusa in addition to its nutraceutical potentials.
Topics: Angiotensin II; Animals; Calcium; Cardiomegaly; Cell Line; Cell Size; Heart; Membrane Potential, Mitochondrial; Mitochondria, Heart; Mitochondrial Membrane Transport Proteins; Mitochondrial Permeability Transition Pore; Mitochondrial Swelling; Myocardium; Nyctaginaceae; Oxidative Stress; Plant Extracts; Rats; Reactive Oxygen Species; Superoxides
PubMed: 24788441
DOI: 10.1371/journal.pone.0096220