Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.6.5.3 (complex I)
 8,901 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The addition of rotenone (inhibitor of respiratory complex I), 3-nitropropionic acid (complex II inhibitor), harmine (inhibitor of complexes I and II) and cyclosporin A (CsA, an inhibitor of the mitochondrial permeability transition) reduced the nuclear damage, loss in the mitochondrial transmembrane potential, cytosolic accumulation of cytochrome c, activation of caspase-3, increase in the formation of reactive oxygen species and depletion of GSH in differentiated PC12 cells treated with MG132, a proteasome inhibitor. Meanwhile, rotenone, 3-nitropropionic acid and harmine did not affect the inhibitory effect of CsA or trifluoperazine (an inhibitor of the mitochondrial permeability transition and calmodulin antagonist) on the cytotoxicity of MG132. The results suggest that proteasome inhibition-induced mitochondrial dysfunction and cell injury may be attenuated by the inhibitions of respiratory chain complex I and II. The cytoprotective effect of the mitochondrial permeability transition prevention not appears to be modulated by respiratory complex inhibition.
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PMID:Depressant effect of mitochondrial respiratory complex inhibitors on proteasome inhibitor-induced mitochondrial dysfunction and cell death in PC12 cells. 1629 13

Heme oxygenase-1 (HO-1) is a cytoprotective enzyme activated by various phytochemicals and we examined the ability of Epigallocatechin-3-gallate (EGCG), the major constituent of green tea, to upregulate HO-1 expression in endothelial cells (ECs). We demonstrate that EGCG induces HO-1 expression in a concentration- and time-dependent manner. Furthermore, EGCG-mediated HO-1 induction was abrogated in the presence of actinomycin D and cycloheximide, indicating that this upregulation of HO-1 occurred at the transcriptional level. EGCG also upregulates Nrf2 levels in nuclear extracts and increases ARE-luciferase activity. Furthermore, EGCG is the most potent inducer of HO-1 expression of the different green tea constituents that we analyzed, but had no detectable cytotoxic effects over the 25-100 microM dosage range. The inhibition of intracellular ROS production by N-acetylcysteine (NAC), glutathione (GSH), superoxide dismutase (SOD), catalase and the mitochondrial complex I inhibitor, rotenone, results in a decrease in EGCG-dependent HO-1 expression. In addition, we determined that tyrosine kinase is involved in EGCG induction of HO-1 as this is abrogated by genistein. ECs treated with EGCG exhibit activation of Akt and ERK1/2. In addition, pharmacological inhibitors of phosphatidylinositol 3-kinase and MEK1/2, which are upstream of Akt and ERK1/2, respectively, attenuate EGCG-induced HO-1 expression. On the other hand, pretreatment of these cells with EGCG exerts significant cytoprotective effects against H2O2, suggesting that the induction of HO-1 is an important component in the protection against oxidative stress. Hence, EGCG is a novel phytochemical inducer of HO-1 expression and we further identify the principal underlying mechanisms involved in this process.
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PMID:Upregulation of heme oxygenase-1 by Epigallocatechin-3-gallate via the phosphatidylinositol 3-kinase/Akt and ERK pathways. 1637 25

We have determined levels of glutathione (GSH), ATP, mitochondrial complex activity and apoptosis rate in proximal tubular cells (PTCs) exfoliated from urine in cystinotic (n=9) and control (n=9) children. Intracellular GSH was significantly depleted in cystinotic PTCs compared with controls (6.8 nmol GSH/mg protein vs 11.8 nmol GSH/mg protein; P<0.001), but there were no significant differences in mitochondrial complex activities or ATP levels under basal conditions. Cystinotic PTCs showed significantly increased apoptosis rate. After PTCs had been stressed by hypoxia, there was further depletion of GSH in cystinotic and control PTCs (2.4 nmol GSH/mg protein vs 7.2 nmol GSH/mg protein; P<0.001). Hypoxic stress led to increased complex I and complex IV activities in control but not in cystinotic PTCs. ATP levels were significantly reduced in cystinotic PTCs after hypoxic stress (12.2 nmol/mg protein vs 26.9 nmol/mg protein; P<0.001). GSH depletion occurs in this in vitro model of cystinotic PTCs, is exaggerated by hypoxic stress and may contribute to reduced ATP and failure to increase complex I/IV activities. Apoptotic rate is also increased, and these mechanisms may contribute to cellular dysfunction in cultured, human cystinotic PTCs.
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PMID:Glutathione depletion and increased apoptosis rate in human cystinotic proximal tubular cells. 1650 73

Exercise significantly influences the progression of atherosclerosis. Oxidized LDL (ox-LDL), as a stimulator of oxidative stress, facilitates monocyte-related atherogenesis. This study investigates how exercise intensity impacts ox-LDL-mediated redox status of monocytes. Twenty-five sedentary healthy men exercised mildly, moderately, and heavily (i.e., 40, 60, and 80% maximal oxygen consumption, respectively) on a bicycle ergometer. Reactive oxygen species (ROS) production, cytosolic and mitochondrial superoxide dismutase (c-SOD and m-SOD, respectively) activities, and total and reduced-form gamma-glutamylcysteinyl glycine (t-GSH and r-GSH, respectively) contents in monocytes mediated by ox-LDL were measured. This experiment obtained the following findings: 1) ox-LDL increased monocyte ROS production and was accompanied by decreased c-SOD and m-SOD activities, as well as t-GSH and r-GSH contents, whereas treating monocytes with diphenyleneiodonium (DPI) (a NADPH oxidase inhibitor) or rotenone/2-thenoyltrifluoroacetone (TTFA) (mitochondrial complex I/II inhibitors) hindered ox-LDL-induced monocyte ROS production; 2) production of ROS and reduction of m-SOD activity and r-GSH content in monocyte by ox-LDL were enhanced by heavy exercise and depressed by mild and moderate exercise; and 3) heavy exercise augmented the inhibition of ox-LDL-induced monocyte ROS production by DPI and rotenone/TTFA, whereas these DPI- and rotenone/TTFA-mediated monocyte ROS productions were unchanged in response to mild and moderate exercise. We conclude that heavy exercise increases ox-LDL-induced monocyte ROS production, possibly by decreasing m-SOD activity and r-GSH content in monocytes. However, mild and moderate exercise likely protects individuals against suppression of anti-oxidative capacity of monocyte by ox-LDL.
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PMID:Role of exercise intensities in oxidized low-density lipoprotein-mediated redox status of monocyte in men. 1672 23

Disruption of mitochondria and free radical mediated tissue injury have been reported during cardiotoxicity induced by isoproterenol (ISO), a beta-adrenergic catecholamine. The present study was designed to investigate the effect of the combination of ferulic acid (FA) and ascorbic acid (AA) on the mitochondrial damage in ISO induced cardiotoxicity. Induction of rats with ISO (150 mg/kg b.wt., i.p.) for 2 days resulted in a significant decrease in the activities of respiratory chain enzymes (NADH dehydrogenase and cytochrome c-oxidase), tricarboxylic acid cycle enzymes (isocitrate dehydrogenase, succinate dehydrogenase, malate dehydrogenase, alpha-ketoglutarate dehydrogenase), mitochondrial antioxidants (GPx, GST, SOD, CAT, GSH), cytochromes (b, c, c1, aa3) and in the level of mitochondrial phospholipids. A marked elevation in mitochondrial lipid peroxidation, mitochondrial levels of cholesterol, triglycerides and free fatty acids were also observed in ISO intoxicated rats. Pre-co-treatment with the combination of FA (20 mg/kg b.wt.) and AA (80 mg/kg b.wt.) orally for 6 days significantly enhanced the attenuation of these functional abnormalities and restored normal mitochondrial function when compared to individual drug treated groups. Mitigation of ISO induced biochemical and morphological changes in mitochondria were more pronounced with a combination of FA and AA rather than the individual drug treated groups. Transmission electron microscopic observations also correlated with these biochemical parameters. Hence, these findings demonstrate the synergistic ameliorative potential of FA and AA on mitochondrial function during beta-adrenergic catecholamine induced cardiotoxicity and associated oxidative stress in rats.
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PMID:Ferulic acid with ascorbic acid synergistically extenuates the mitochondrial dysfunction during beta-adrenergic catecholamine induced cardiotoxicity in rats. 1676 44

Steatohepatitis represents an advanced stage of fatty liver disease that encompasses alcoholic (ASH) and non-alcoholic steatohepatitis (NASH). The progression from steatosis to steatohepatitis is poorly understood. One of the clues to this progression is the sensitization of hepatocytes to oxidative stress and cytokine-induced cell death. Mitochondrial glutathione (mGSH), which plays a central role in the control of mitochondrial reactive oxygen species (ROS) generation, modulates the sensitivity to cell death pathways. Mitochondrial GSH depletion due to alcohol-mediated alteration in mitochondrial membrane dynamics underlies the susceptibility of hepatocytes from alcohol-fed models to tumor necrosis factor (TNF), and in nutritional and genetic models of hepatic steatosis, mGSH depletion occurs due to the enrichment of mitochondria in free cholesterol, resulting in decreased mitochondrial membrane fluidity. The signaling of TNF through its membrane receptor TNFR1 from complex I to complex II is similar in hepatocytes depleted or not depleted in mGSH, yet hepatocellular susceptibility to TNF occurs if mGSH is depleted. Thus, mGSH is a critical factor in the development of steatohepatitis through sensitization of hepatocytes to inflammatory cytokines, and understanding the homeostasis of cholesterol and its trafficking to mitochondria may be of relevance in the pathophysiology of ASH and NASH.
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PMID:Mitochondrial glutathione: hepatocellular survival-death switch. 1695 67

The pathogenesis underlying the selective degeneration of nigral dopaminergic neurons in Parkinson's disease is not fully understood but several lines of evidence implicate the role of oxidative stress and mitochondrial dysfunction. Depletion in levels of the thiol reducing agent glutathione (GSH + GSSG) is the earliest reported biochemical event to occur in the Parkinsonian substantia nigra prior to selective loss of complex I (CI) activity associated with the disease believed to contribute to subsequent dopaminergic cell death. Recent studies from our laboratory have demonstrated that acute reduction in both cellular and mitochondrial glutathione levels results in increased oxidative stress and a decrease in mitochondrial function linked to a selective decrease in CI activity through an NO-mediated mechanism (Jha, N.; Jurma, O.; Lalli, G.; Liu, Y.; Pettus, E. H.; Greenamyre, J. T.; Liu, R. M.; Forman, H. J.; Andersen, J. K. Glutathione depletion in PC12 results in selective inhibition of mitochondrial complex I activity. Implications for Parkinson's disease J. Biol. Chem. 275: 26096-26101; 2000. Hsu, M.; Srinivas, B.; Kumar, J.; Subramanian, R.; Andersen, J. Glutathione depletion resulting in selective mitochondrial complex I inhibition in dopaminergic cells is via an NO-mediated pathway not involving peroxynitrite: implications for Parkinson's disease J. Neurochem. 92: 1091-1103.2005.). However, the effect of prolonged glutathione depletion on dopaminergic cells is not known. In this present study, using low concentrations of buthionine-S-sulfoximine, a chemical inhibitor of the de novo glutathione synthesizing enzyme glutamate cysteine ligase, we developed a chronic model in which glutathione depletion in dopaminergic N27 cells for a 7-day period was found to lead to inhibition of CI activity via a peroxynitrite-mediated event which is reversible by the thiol reducing agent, dithiothreitol, and coincides with increased S-nitrosation of mitochondrial proteins.
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PMID:Reversible inhibition of mitochondrial complex I activity following chronic dopaminergic glutathione depletion in vitro: implications for Parkinson's disease. 1702 71

Parkinson's disease (PD) is associated with loss of total glutathione (GSH) which may contribute to progressive cell death. Peripheral GSH administration has been used clinically with reported benefits. Despite this, there is little specific information to characterize its cellular uptake or clearance, brain elevation with peripheral delivery or neuroprotective efficacy in PD models. The current study was carried out to provide this information using in vitro and in vivo approaches. In rat mesencephalic culture, the monoethyl ester of GSH (GEE), but not GSH (1-10 mM, 24 h) produced a dose-dependent elevation in GSH. The half-life for clearance was 10.14 h and was not different in cells depleted of GSH prior to loading. Elevation of GSH with GEE protected neurons from oxidative stress with H2O2 or metabolic stress with the complex I and II inhibitors MPP+ and malonate, respectively. To determine if peripheral administration of GEE could elevate brain GSH levels, rats were administered 0.1-50 mg/kg/day GEE via osmotic minipump either subcutaneously (sc) or via a cannula placed into the left cerebral ventricle (icv) for 28 days. Only central delivery of GEE resulted in significant elevations of brain GSH. Elevation of brain GSH by icv infusion of GEE was examined for its neuroprotective effects against chronic central delivery of MPP+. Infusion of 0.142 mg/kg/day MPP+ for 28 days caused a selective ipsilateral loss of striatal dopamine. Co-infusion of MPP+ with 10 mg/kg/day GEE significantly protected against striatal dopamine loss. These findings show that the ethyl ester of GSH but not GSH per se can elevate intracellular GSH, that brain elevation of GSH requires central delivery of the ethyl ester and that this elevation provides neuroprotection against oxidative stress or chronic mitochondrial impairment.
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PMID:Characterization of intracellular elevation of glutathione (GSH) with glutathione monoethyl ester and GSH in brain and neuronal cultures: relevance to Parkinson's disease. 1704 15

Nitroglycerin (GTN) tolerance was induced in vivo (rats) and in vitro (rat and human vessels). Electrochemical detection revealed that the incubation dose of GTN (5x10(-6) mol/L) did not release NO or modify O(2) consumption when administered acutely. However, development of tolerance produced a decrease in both mitochondrial O(2) consumption and the K(m) for O(2) in animal and human vessels and endothelial cells in a noncompetitive action. GTN tolerance has been associated with impairment of GTN biotransformation through inhibition of aldehyde dehydrogenase (ALDH)-2, and with uncoupling of mitochondrial respiration. Feeding rats with mitochondrial-targeted antioxidants (mitoquinone [MQ]) and in vitro coincubation with MQ (10(-6) mol/L) or glutathione (GSH) ester (10(-4) mol/L) prevented tolerance and the effects of GTN on mitochondrial respiration and ALDH-2 activity. Biotransformation of GTN requires functionally active mitochondria and induces reactive oxygen species production and oxidative stress within this organelle, as it is inhibited by mitochondrial-targeted antioxidants and is absent in HUVECrho(0) cells. Experiments analyzing complex I-dependent respiration demonstrate that its inhibition by GTN is prevented by mitochondrial-targeted antioxidants. Furthermore, in presence of succinate (10x10(-3) mol/L), a complex II electron donor added to bypass complex I-dependent respiration, GTN-treated cells exhibited O(2) consumption rates similar to those of controls, thus suggesting that complex I was affected by GTN. We propose that, following prolonged treatment with GTN in addition to ALDH-2, complex I is a target for mitochondrially generated reactive oxygen species. Our data also suggest a role for mitochondrial-targeted antioxidants as therapeutic tools in the control of the tolerance that accompanies chronic nitrate use.
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PMID:Complex I dysfunction and tolerance to nitroglycerin: an approach based on mitochondrial-targeted antioxidants. 1705 93

beta-N-oxalyl-amino-L-alanine, (L-BOAA), an excitatory amino acid, acts as an agonist of the AMPA subtype of glutamate receptors. It inhibits mitochondrial complex I in motor cortex and lumbosacral cord of male mice through oxidation of critical thiol groups, and glutaredoxin, a thiol disulfide oxido-reductase, helps maintain integrity of complex I. Since incidence of neurolathyrism is less common in women, we examined the mechanisms underlying the gender-related effects. Inhibition of complex I activity by L-BOAA was seen in male but not female mice. Pretreatment of female mice with estrogen receptor antagonist ICI 182,780 or tamoxifen sensitizes them to L-BOAA toxicity, indicating that the neuroprotection is mediated by estrogen receptors. L-BOAA triggers glutathione (GSH) loss in male mice but not in female mice, and only a small but significant increase in oxidized glutathione (GSSG) was seen in females. As a consequence, up-regulation of gamma-glutamyl cysteinyl synthase (the rate-limiting enzyme in glutathione synthesis) was seen only in male mouse CNS but not in females. Both glutathione reductase and glutaredoxin that reduce oxidized glutathione and protein glutathione mixed disulfides, respectively, were constitutively expressed at higher levels in females. Furthermore, glutaredoxin activity in female mice was down-regulated by estrogen antagonist indicating its regulation by estrogen receptor. The higher constitutive expression of glutathione reductase and glutaredoxin could potentially confer neuroprotection to female mice.
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PMID:Down-regulation of glutaredoxin by estrogen receptor antagonist renders female mice susceptible to excitatory amino acid mediated complex I inhibition in CNS. 1710 34


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