Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.24.23 (MMP)
 4,246 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Comparative kinetic analyses of the mechanisms of toxicity of the alkylphenol eugenol and its putative toxic metabolite (quinone methide, EQM) were carried out in cultured rat liver cells (Clone 9, ATCC) using a variety of vital fluorescence bioassays with a Meridian Ultima laser cytometer. Parameters monitored included intracellular GSH and calcium levels ([Ca2+]i), mitochondrial and plasma membrane potentials (MMP and PMP), intracellular pH, reactive oxygen species (ROS) generation, and gap junction-mediated intercellular communication (GJIC). Cells were exposed to various concentrations of test compounds (1 to 1000 microM) and all parameters monitored directly after addition at 15 s intervals for at least 10 min. Eugenol depleted intracellular GSH, inhibited GJIC and generation of ROS, and had a modest effect on MMP at concentrations of 10 to 100 microM. At high concentrations (1000 microM), eugenol also affected [Ca2+]i, PMP, and pH. Effects of EQM were seen at lower concentrations (1 to 10 microM). The earliest and most potent effects of either eugenol or EQM were seen on GSH levels and GJIC. Coadministration of glutathione ethyl ester enhanced intracellular GSH levels by almost 100% and completely protected cells from cell death caused by eugenol and EQM. These results suggest that eugenol mediates its hepatotoxic effects primarily through depletion of cytoprotective thiols and interference in thiol-dependent processes such as GJIC. Furthermore, our results support the hypothesis that the toxic effects of eugenol are mediated through its quinone methide metabolite.
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PMID:Comparative toxicity of eugenol and its quinone methide metabolite in cultured liver cells using kinetic fluorescence bioassays. 951 27

UW solution and HTK solution are both used for cold preservation of liver allografts. Although they are about equally effective, their compositions are very different, and they were formulated using different rationales. The authors recently showed an important role for MMPs in liver preservation injury and consequently postulated that these preservation solutions contain cryptic inhibitors of MMP activity. To determine this possibility, the ability of these solutions to inhibit MMP activity was studied. The source of MMP2 and MMP9 was human liver effluents obtained at the time of liver transplantation or commercially available human recombinant MMP2 and MMP9. MMP2 and MMP9 showed gelatinolytic activity at 37 degrees C and also at 4 degrees C, although activity at 4 degrees C was reduced. Activity was inhibited by University of Wisconsin (UW) and Histidine/Tryptophan/ Ketoglutarate (HTK) solutions. Examination of individual ingredients disclosed that reduced glutathione (GSH) and lactobionate in UW solution and histidine in HTK solution were the cryptic inhibitors. HTK solution was a more effective inhibitor than UW solution. GSH inhibited the activity of both enzymes, but was a much more effective inhibitor of MMP9 than MMP2. Oxidized glutathione(GSSG) was a much less effective inhibitor of the enzymes. The inhibitor constants (K(i)) of GSH for MMP2 and MMP9 were 34 micromol/L and 3 micromol/L, respectively. The authors conclude that MMP inhibition is a cryptic property of both commonly used liver preservation solutions and contributes importantly to their action. Furthermore, GSH appears to be an effective inhibitor of gelatinases at concentrations at which it is normally present in extracellular fluid.
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PMID:Glutathione, lactobionate, and histidine: cryptic inhibitors of matrix metalloproteinases contained in University of Wisconsin and histidine/tryptophan/ketoglutarate liver preservation solutions. 1079 87

Mitochondrial electron transport inhibitors induced two distinct pathways for acute cell death: lipid peroxidation-dependent and -independent in isolated rat hepatocytes. The toxic effects of mitochondrial complex I and II inhibitors, rotenone (ROT) and thenoyltrifluoroacetone (TTFA), respectively, were dependent on oxidative stress and lipid peroxidation, while cell death induced by inhibitors of complexes III and IV, antimycin A (AA) and cyanide (CN), respectively, was caused by MMP collapse and loss of cellular ATP. Accordingly, cellular and mitochondrial antioxidant depletion or supplementation, in general, resulted in a dramatic potentiation or prevention, respectively, of toxic injury induced by complex I and II inhibitors, with little or no effect on complex III and IV inhibitor-induced toxicity. ROT-induced oxidative stress was prevented by the addition of d-alpha-tocopheryl succinate (TS) but surprisingly TS did not afford hepatocytes protection against TTFA-induced oxidative damage. TS treatment prevented ROT-induced mitochondrial lipid hydroperoxide formation but had no effect on the loss of mitochondrial GSH or cellular ATP, suggesting a mitochondrial lipid peroxidation-mediated mechanism for ROT-induced acute cell death. In contrast, only fructose treatment provided excellent cytoprotection against AA- and CN-induced toxicity. Our findings indicate that complex III and IV inhibitors cause a rapid and severe depletion of cellular ATP content resulting in acute cell death that is dependent on cellular energy impairment but not lipid peroxidation. In contrast, inhibitors of mitochondrial complex I or II moderately deplete cellular ATP levels and thus cause acute cell death via a lipid peroxidation pathway.
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PMID:Mitochondrial electron transport inhibitors cause lipid peroxidation-dependent and -independent cell death: protective role of antioxidants. 1151 65

Flavonoids exist extensively in plants, and several biological effects of them have been demonstrated. Wogonin is an important flavonoid compound. In this study, wogonin showed obvious growth inhibition on Bel-7402 cells. The major mechanisms of inhibition included cell apoptosis and cytotoxic effects. Wogonin-induced cell death showed characteristics of apoptosis including DNA fragmentation, chromatin condensation, appearance of apoptotic bodies, and an increase in hypodiploid cells. However, the percentage of necrosis cells also increased with the increase of wogonin concentration. Furthermore, treatment with wogonin caused changes of reactive oxygen species (ROS) and mitochondrial membrane potentials (DeltaPsim, MMP), the decrease of the ratio of reduced and oxidized glutathione (GSH/GSSG), cytochrome c release and activation of caspase-9.
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PMID:Changes in mitochondrial membrane potential and reactive oxygen species during wogonin-induced cell death in human hepatoma cells. 1730 Jul

Studies have illustrated that fatty acids, especially polyunsaturated fatty acids (PUFA), have a role in regulating oxidative stress via the enhancement of antioxidative defense capacity or the augmentation of oxidative burden. Elevated oxidative stress has been implicated in the pathogenesis of brain injury associated with cerebral ischemia/reperfusion (I/R). The objective of this study was to assess whether treatment with fatty acids after focal cerebral I/R induced by occlusion of the common carotid arteries and the middle cerebral artery has effects on brain injury in a rat model. PUFA, including arachidonic acid (AA) and docosahexaenoic acid (DHA), and the saturated fatty acid, stearic acid (SA), were administrated 60 min after reperfusion via intraperitoneal injection. AA and DHA aggravated cerebral ischemic injury, which manifested as enlargement of areas of cerebral infarction and increased impairment of motor activity, in a concentration-dependent manner. However, there were no remarkable differences in post-ischemic alterations between the SA and saline groups. The post-ischemic augmentation of injury in AA and DHA treatment groups was accompanied by increases in the permeability of the blood-brain barrier (BBB), brain edema, metalloproteinase (MMP) activity, inflammatory cell infiltration, cyclooxygenase 2 (COX-2) expression, caspase 3 activity, and malondialdehyde (MDA) production, and by a decrease in the brain glutathione (GSH) content. Furthermore, we found that either AA or DHA alone had little effect on free radical generation in neuroglia, but they greatly increased the hydrogen peroxide-induced oxidative burden. Taken together, these findings demonstrate the detrimental effect of PUFA such as AA and DHA in post-ischemic progression and brain injury after cerebral I/R is associated with augmentation of cerebral I/R-induced alterations, including oxidative changes.
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PMID:Detrimental effects of post-treatment with fatty acids on brain injury in ischemic rats. 1785 1

Matrix metalloproteinase-2 (MMP-2) has emerged as a key protease in various pathologies associated with oxidative stress, including myocardial ischemia-reperfusion, heart failure or inflammation. Peroxynitrite (ONOO(-)), an important effector of oxidative stress, was reported to activate some full length MMP zymogens, particularly in the presence of glutathione (GSH), but whether this occurs for MMP-2 is unknown. Treating MMP-2 zymogen with ONOO(-) resulted in a concentration-dependent regulation of MMP-2, with 0.3-1 microM ONOO(-) increasing and 30-100 microM ONOO(-) attenuating enzyme activity. The enzyme's V(max) was also significantly increased by 1 microM ONOO(-). Comparable responses to ONOO(-) treatment were observed using the intracellular target of MMP-2, troponin I (TnI). GSH at 100 microM attenuated the effects of ONOO(-) on MMP-2. Mass spectrometry revealed that ONOO(-) can oxidize and, in the presence of GSH, S-glutathiolate the MMP-2 zymogen or a synthetic peptide containing the cysteine-switch motif in the enzyme's autoinhibitory domain. These results suggest that ONOO(-) and GSH can modulate the activity of 72 kDa MMP-2 by modifying the cysteine residue in the autoinhibitory domain of the zymogen, a process that may be relevant to pathophysiological conditions associated with increased oxidative stress.
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PMID:Activation and modulation of 72kDa matrix metalloproteinase-2 by peroxynitrite and glutathione. 1904 43

Propyl gallate (PG) as a synthetic antioxidant is widely used in processed food and medicinal preparations. It also exerts a variety of effects on tissue and cell functions. In the present study, we investigated the effects of L-buthionine sulfoximine (BSO, an inhibitor of GSH synthesis), diethyldithiocarbamate (DDC, an inhibitor of Cu/Zn-SOD) or 3-amino-1,2,4-triazole (AT, an inhibitor of catalase) on PG-treated HeLa cells in relation to cell growth, reactive oxygen species (ROS) and glutathione (GSH). Treatment with PG induced growth inhibition, the loss of mitochondrial membrane potential [MMP (DeltaPsim)] and apoptosis in HeLa cells. ROS levels including O2.- were increased or decreased in PG-treated HeLa cells depending on the incubation times. PG caused depletion in GSH content in HeLa cells. While BSO enhanced the growth inhibition of PG-treated HeLa cells at 4 h, DDC and AT did not. All the agents down-regulated MMP (DeltaPsim) levels in PG-treated cells. Although BSO, DDC or AT slightly increased ROS or O2.- levels in PG-treated cells at 1 h, these enhancements of ROS did not intensify apoptosis in these cells. In addition, BSO, DDC or AT slightly reduced GSH level in PG-treated HeLa cells at 1 h, but this reduction did not affect cell death of HeLa. Furthermore, PG induced a G1 phase arrest of the cell cycle. BSO, DDC or AT significantly inhibited the G1 phase arrest in PG-treated cells. Conclusively, the changes of ROS and GSH levels by BSO, DDC or AT in PG-treated HeLa cells did not strongly affect the cell growth and death.
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PMID:The effects of buthionine sulfoximine, diethyldithiocarbamate or 3-amino-1,2,4-triazole on propyl gallate-treated HeLa cells in relation to cell growth, reactive oxygen species and glutathione. 1957 99

Antimycin A (AMA) inhibits succinate oxidase, NADH oxidase, and mitochondrial electron transport chain between cytochrome b and c. We recently demonstrated that AMA inhibited the growth of Calu-6 lung cancer cells through apoptosis. Here, we investigated the effects of AMA and/or MAPK inhibitors on Calu-6 lung cancer cells in relation to cell growth, cell death, reactive oxygen species (ROS), and GSH levels. Treatment with AMA inhibited the growth of Calu-6 cells at 72 h. AMA-induced apoptosis was accompanied by the loss of mitochondrial membrane potential (MMP; Delta Psi m). While ROS were decreased in AMA-treated Calu-6 cells, O2.- among ROS was increased. AMA also induced GSH depletion in Calu-6 cells. Treatment with MEK inhibitor intensified cell death, MMP (Delta Psi m) loss, and GSH depletion in AMA-treated Calu-6 cells. JNK inhibitor also increased cell death, MMP (Delta Psi m) loss, and ROS levels in these cells. Treatment with p38 inhibitor magnified cell growth inhibition by AMA and increased cell death, MMP (Delta Psi m) loss, ROS level, and GSH depletion in AMA-treated cells. Conclusively, all the MAPK inhibitors slightly intensified cell death in AMA-treated Calu-6 cells. The changes of ROS and GSH by AMA and/or MAPK inhibitors were in part involved in cell growth and death in Calu-6 cells.
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PMID:The effects of MAPK inhibitors on antimycin A-treated Calu-6 lung cancer cells in relation to cell growth, reactive oxygen species, and glutathione. 1971 50

Pyrogallol (PG) as a polyphenol compound induces apoptosis in several types of cells. Here, we investigated the effects of MAPK inhibitors on PG-treated calf pulmonary artery endothelial cells (CPAEC) in relation to cell death, ROS and GSH. PG inhibited the growth of CPAEC and also induced cell death, which was accompanied by the loss of mitochondrial membrane potential (MMP; DeltaPsi(m)). PG decreased the ROS level and increased the GSH depleted cell number in CPAEC. JNK inhibitor intensified the growth inhibition by PG whereas p38 inhibitor attenuated the growth inhibition. While MEK and p38 inhibitors decreased CPAEC death by PG, JNK inhibitor increased. None of the MAPK inhibitors significantly increased ROS level in PG-treated CPAEC. JNK inhibitor increased GSH depleted cell number in PG-treated CPAEC whereas p38 inhibitor decreased the number. MAPK inhibitors differently affected cell growth, death, ROS and GSH levels in control CPACE. In conclusion, PG induced apoptosis via the loss of MMP (DeltaPsi(m)) in CPAEC, which is accompanied by GSH depletion. JNK and p38 inhibitors increased and decreased apoptosis in PG-treated CPAEC, respectively, which were correlated with GSH depletion.
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PMID:JNK and p38 inhibitors increase and decrease apoptosis, respectively, in pyrogallol-treated calf pulmonary arterial endothelial cells. 1978 7

Pyrogallol (PG) as a polyphenol compound can generate superoxide anion (O(2)(-)). Here, we investigated the effects of PG and/or MAPK inhibitors on Calu-6 lung cells in relation to cell growth, cell death, reactive oxygen species (ROS) and GSH levels. PG inhibited the growth of Calu-6 cells and induced apoptosis, which was accompanied by the loss of mitochondrial membrane potential (MMP; DeltaPsi(m)). While general ROS were decreased in PG-treated Calu-6 cells at 72h, intracellular O(2)(-) level including mitochondrial O(2)(-) was increased. PG also increased GSH depleted cell number in Calu-6 cells. MEK inhibitor slightly prevented cell growth inhibition, cell death and GSH depletion by PG. JNK inhibitor did not affect cell growth, cell death, MMP (DeltaPsi(m)) loss, ROS level and GSH deletion in PG-treated Calu-6 cells but p38 inhibitor mildly enhanced MMP (DeltaPsi(m)) loss, O(2)(-) level and GSH depletion in these cells. Conclusively, MEK inhibitor slightly prevented growth inhibition and death in PG-treated Calu-6 cells. Growth inhibition and death in Calu-6 cells by PG and/or MAPK inhibitors were partially related to O(2)(-) level and GSH content changes.
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PMID:The effects of MAPK inhibitors on pyrogallol-treated Calu-6 lung cancer cells in relation to cell growth, reactive oxygen species and glutathione. 1983 63


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