Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.4.2.30 (PARP)
13,611 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Myocyte injury due to myocardial reperfusion injury plays a crucial role in the pathogenesis of acute myocardial infarction even after successful coronary revascularization. Identification of compounds that reduce reperfusion-associated myocyte death is important. Therefore, we developed an in vitro model of myocardial reperfusion injury in H9c2 rat cardiomyocytes and applied a cell-based high-throughput approach to screen a standard library of pharmacologically active compounds (LOPAC) in order to identify drugs with cardioprotective effects. Oxidative stress was induced with hydrogen peroxide (H2O2) treatment, which resulted in approximately 50% reduction in cell viability. Test compounds were added at a 3-microM final concentration as a pretreatment or in a delayed fashion (30 min after the peroxide challenge in order to imitate pharmacological treatment following angioplasty). Cells were cultured for 3 or 24 h. Viability was quantitated with the methylthiazolyldiphenyl-tetrazolium bromide method. Cytotoxicity and cytoprotection were also evaluated by measuring the lactate dehydrogenase activity in the cell culture supernatant. The screening identified a number of compounds with cytoprotective action, including molecules that are known to interfere with components of DNA repair and cell cycle progression, e.g. poly(ADP-ribose) polymerase (PARP) inhibitors, topoisomerase inhibitors, and cyclin dependent kinase inhibitors, or reduce energy consumption by interfering with cardiac myofilament function. A number of dopamine D1 receptor agonists also provided significant cytoprotection at 3 h, but only three of them showed a similar effect at 24 h: chloro- and bromo-APB and chloro-PB hydrobromide. Chloro-APB hydrobromide significantly reduced peroxide-induced PARP activation in the myocytes independently of its action on dopamine D1 receptors, but lacked PARP inhibitor capacity in a cell-free PARP assay system. In conclusion, the pattern of cytoprotective drugs identified in the current assay supports the overall validity of our model system. The findings demonstrate that cytoprotective agents, including novel indirect inhibitors of cellular PARP activation can be identified with the method, chloro-APB hydrobromide being one such compound. The current experimental setting can be employed for cell-based high-throughput screening of various compound libraries.
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PMID:Oxidant-induced cardiomyocyte injury: identification of the cytoprotective effect of a dopamine 1 receptor agonist using a cell-based high-throughput assay. 1791 70

Oridonin, a diterpenoid isolated from the plant Rabdosia rubescens, induces human epidermoid carcinoma A431 cell death through apoptosis and tyrosine kinase pathway. To examine the pathway of oridonin-induced A431 cell death, morphologic observation, lactate dehydrogenase activity-based assay, DNA agarose gel electrophoresis and Western blot analysis were carried out. When A431 cells, which overexpress epidermal growth factor receptor (EGFR), were treated with oridonin, caspase-3 was activated followed by the degradation of caspase-3 substrates, inhibitor of caspase-activated DNase (ICAD) and poly(ADP-ribose) polymerase (PARP) in a time-dependent manner. Oridonin promoted the release of cytochrome c and the down-regulation of mitochondrial transmembrane potential (DeltaPsim). Oridonin up-regulated the expression ratio of mitochondrial proteins, Bax/Bcl-2. In addition, the total tyrosine kinase activity of A431 cellular proteins and the expression of EGFR were markedly reduced after oridonin treatment. Taken together, oridonin induced apoptosis in A431 cells via mitochondrial pathway, activation of caspase-3 and inhibition of tyrosine kinase activities.
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PMID:Oridonin induces human epidermoid carcinoma A431 cell apoptosis through tyrosine kinase and mitochondrial pathway. 1805 84

The objective of this study was to investigate the chemopreventive potentials of glycine- and proline-rich glycoprotein (SNL glycoprotein, 150-kDa) isolated from Solanum nigrum Linne on formation of colonic aberrant crypt foci (ACF) induced by 1,2-dimethylhydrazine (DMH, 20 mg/kg) in A/J mice. Administration of SNL glycoprotein inhibited phosphorylation of extracellular signal-regulated kinase (ERK), expression of colonic proliferating cell nuclear antigen (PCNA), and frequency of colonic ACF in DMH-stimulated mice colon carcinogenesis. In addition, SNL glycoprotein increased expression of cyclin-dependent kinase inhibitors (p21(WAF/Cip1) and p27(Kip1)), whereas reduced expression of precursor form of apoptosis-related proteins [pro-caspase-3 and pro-poly(ADP-ribose)polymerase (PARP)] in the mice. Interestingly, the results in this study revealed that SNL glycoprotein has suppressive effects on activity of nuclear factor-kappa B (NF-kappaB), whereas it has stimulatory effect on the expression of p53, accompanying inhibitory effects on expression of NF-kappaBp50, inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), interleukin (IL)-6, and tumor necrosis factor (TNF)-alpha in DMH-stimulated ACF formation. Also, SNL glycoprotein has inhibitory effects on the formation of thiobarbituric acid reactive substances (TBARS), on the production of inducible nitric oxide (NO), and on the release of lactate dehydrogenase (LDH) in the mice plasma. Collectively, our findings in this study suggest that SNL glycoprotein has chemopreventive activity via modulation of cell proliferation and apoptosis in DMH-treated A/J mice.
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PMID:Glycine- and proline-rich glycoprotein regulates the balance between cell proliferation and apoptosis for ACF formation in 1,2-dimethylhydrazine-treated A/J mice. 1918 65

In this study we examined interactions between human dermal fibroblasts and chromium acetate hydroxide originating from environmental waste sediments. We show that initially exposure of fibroblasts to Cr (III) induced membrane-dependent signaling including activation of Rac1 GTPase, Src and apoptosis signal-regulating kinase 1 (ASK-1) kinases leading to increased activities of p38 and particularly Jun N-terminal kinase (JNK) and subsequent activation of caspase-3. At later treatment intervals (48-96 h), caspase-3 activity became suppressed and markedly increased lactate dehydrogenase (LDH) release was observed. Further experiments demonstrated that LDH release occurred in the presence of increased oxidative stress, extensive DNA damage, overactivation of poly(ADP-ribose)polymerase-1 (PARP-1) and depletion of ATP. Using specific inhibitors it was demonstrated that oxidative stress along with PARP-1 activity are responsible for cell death mode switch and upon their inhibition caspase-3 activity could be restored. In conclusion, Cr (III) seems to induce a biphasic response in dermal fibroblasts, with initial apoptosis switched to necrosis via increased DNA damage and resulting PARP-1 activity.
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PMID:Trivalent chromium activates Rac-1 and Src and induces switch in the cell death mode in human dermal fibroblasts. 1940 21

While lung cancer accounts for approximately 20% of cancer diagnoses, it is the leading cause of tumor-related deaths. The apoptotic effects of 3,5,4'-trihydroxystilbene (resveratrol), dibenzoylmethane (DBM), and their analogues on human lung cancer cells are generally unclear. The aims of this study were to evaluate the apoptotic effects and molecular mechanisms of resveratrol, DBM, and their analogues on human lung cancer cells. The results of the MTT and lactate dehydrogenase (LDH) leakage assays indicated that resveratrol, 3,5,4'-trimethoxy-trans-stilbene (MR-3), and 1-(2-hydroxy-5-methylphenyl)-3-phenyl-1,3-propanedione (HMDB) could inhibit cell population growth and induce cell injury in A549 and CH27 cell lines. Resveratrol and HMDB could induce apoptotic cell death in the A549 and CH27 cell lines. Moreover, cellular growth of the A549 and CH27 cell lines might be inhibited by MR-3 through induction of apoptosis and regulation of the cell cycle. The A549 and CH27 cell lines treated with resveratrol, MR-3, and HMDB showed a time-dependent reduction of mitochondrial membrane potential, and the Bax/Bcl-2 ratio increased gradually with a higher concentration of polyphenols. The resveratrol-, MR-3-, and HMDB-induced apoptosis in the A549 and CH27 cell lines were controlled through activation of caspase-9 and caspase-3 and subsequent cleavage of PARP. In conclusion, we have demonstrated that resveratrol, DBM, and their analogues could be effective candidates for chemoprevention of lung cancer and HMDB might have the strongest ability for inducing apoptosis.
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PMID:Mechanisms of apoptotic effects induced by resveratrol, dibenzoylmethane, and their analogues on human lung carcinoma cells. 1944 15

There is growing evidence implicating the kynurenine pathway (KP) and particularly one of its metabolites, quinolinic acid (QUIN), as important contributors to neuroinflammation in several brain diseases. While QUIN has been shown to induce neuronal and astrocytic apoptosis, the exact mechanisms leading to cell death remain unclear. To determine the mechanism of QUIN-mediated excitotoxicity in human brain cells, we measured intracellular levels of nicotinamide adenine dinucleotide (NAD(+)) and poly(ADP-ribose) polymerase (PARP) and extracellular lactate dehydrogenase (LDH) activities in primary cultures of human neurons and astrocytes treated with QUIN. We found that QUIN acts as a substrate for NAD(+) synthesis at very low concentrations (<50 nM) in both neurons and astrocytes, but is cytotoxic at sub-physiological concentrations (>150 nM) in both the cell types. We have shown that the NMDA ion channel blockers, MK801 and memantine, and the nitric oxide synthase (NOS) inhibitor, L-NAME, significantly attenuate QUIN-mediated PARP activation, NAD(+) depletion, and LDH release in both neurons and astrocytes. An increased mRNA and protein expression of the inducible (iNOS) and neuronal (nNOS) forms of nitric oxide synthase was also observed following exposure of both cell types to QUIN. Taken together these results suggests that QUIN-induced cytotoxic effects on neurons and astrocytes are likely to be mediated by an over activation of an NMDA-like receptor with subsequent induction of NOS and excessive nitric oxide (NO(*))-mediated free radical damage. These results contribute significantly to our understanding of the pathophysiological mechanisms involved in QUIN neuro- and gliotoxicity and are relevant for the development of therapies for neuroinflammatory diseases.
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PMID:Mechanism for quinolinic acid cytotoxicity in human astrocytes and neurons. 1952 1

The present study was designed to investigate the cardio-protective effect of Ac-LEDH-cmk a selective caspase-9 inhibitor and 5-aminoisoquinolinone a selective Poly (ADP-ribose) polymerase inhibitor on ischemia and reperfusion induced apoptotic and necrotic cell death in rats. Isolated rat hearts were exposed to 30 minutes of global ischemia followed by 120 minutes of reperfusion using Langendorff's apparatus. Myocardial injury was assessed in the terms of infarct size, release of lactate dehydrogenase, creatine kinase enzymes and apoptotic index was assessed by DNA smearing on agarose gel electrophoresis. Pretreatments with specific inhibitor of caspase-9, Ac-LEHD-cmk (0.07 muM and 0.105 muM), and inhibitor of PARP, 5-aminoisoquinolinone (5 microM and 7.5 muM), significantly attenuated I/R induced increase in infarct size, release of lactate dehydrogenase and creatine kinase in the coronary effluent, and apoptotic index. Therefore, it may be concluded that inhibition of caspase-9 and PARP prevent ischemia and reperfusion-induced activation of apoptotic cascade and necrosis in rat myocardium.
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PMID:Protective effects of caspase-9 and poly(ADP-ribose) polymerase inhibitors on ischemia-reperfusion-induced myocardial injury. 1964 85

N,N-Dimethylformamide (DMF) is an organic solvent extensively used in industries such as synthetic leather, fibers and films, and induces liver toxicity and carcinogenesis. Despite a series of experimental and clinical reports on DMF-induced liver failure, the mechanism of toxicity is yet unclear. This study investigated whether DMF in combination with a low dose of hepatotoxicant enhances hepatotoxicity, and if so, on what mechanistic basis. Treatment of rats with either DMF (50-500mg/kg/day, for 3 days) or a single low dose of CCl(4) (0.2ml/kg) alone caused small increases in plasma transaminases and lactate dehydrogenase activities. However, combinatorial treatment of DMF with CCl(4) markedly increased blood biochemical changes. Histopathology confirmed the synergism in hepatotoxicity. Moreover, DMF+CCl(4) caused PARP cleavage and caspase-3 activation, but decreased the level of Bcl-xL, all of which confirmed apoptosis of hepatocytes. Consistently, DMF+CCl(4) treatment markedly increased lipid peroxidation. By contrast, treatment of DMF in combination with lipopolysaccharide, acetaminophen or d-galactosamine caused no enhanced hepatotoxicity. Given the link between endoplasmic reticulum (ER) dysfunction and cell death, ER stress response was monitored after DMF and/or CCl(4) treatment. Whereas either DMF or CCl(4) treatment alone marginally changed the expression levels of glucose-regulated protein 78 and 94 and phosphorylated PKR-like ER-localized eIF2alpha kinase, concomitant treatment with DMF and CCl(4) synergistically induced them with increases in glucose-regulated protein 78 and C/EBP homologous protein mRNAs. Our results demonstrate that DMF treatment in combination with CCl(4) synergistically increases hepatocyte death, which may be associated with the induction of severe ER stress.
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PMID:Synergistic hepatotoxicity of N,N-dimethylformamide with carbon tetrachloride in association with endoplasmic reticulum stress. 2009 84

Cadmium is reported to accumulate in human eye tissues suggesting its implication in diverse ocular pathology. Using an in vitro cell culture model we investigated the effects of cadmium on human lens epithelial cells (HLECs) (HLE-B3). We observed cadmium-induced dose- as well as time-dependent decline in HLECs viability which was exacerbated significantly upon reduction of intracellular glutathione levels by buthionine sulfoximine (BSO). There was a dose-dependent significant increase in lactate dehydrogenase (LDH) release from HLECs suggesting cadmium-induced alteration of membrane integrity as well as necrotic cell death. The decline in cell viability was also due to apoptosis of the HLECs as determined by quantifying % apoptotic cells as well as PARP cleavage. Moreover, release of apoptosis inducing factor (AIF) into the cytosol was also detected. Cadmium was also observed to increase oxidative stress, lipid peroxidation and activation of MAPK pathway in HLECs. Antioxidants like N-acetylcysteine (NAC) and alpha-Tocopherol significantly prevented cadmium-induced toxicity in HLECs. Our findings suggest that cadmium-induced elevated oxidative stress as well as activation of MAPK signaling cascade eventually led to cell death of HLECs through apoptosis as well as necrosis. The loss of HLECs by cadmium could possibly explain its implication in cataract development particularly associated with smoking.
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PMID:Cadmium-induced induction of cell death in human lens epithelial cells: implications to smoking associated cataractogenesis. 2043 8

Beta-amyloid (Abeta) peptide, the hallmark of Alzheimer's disease (AD), invokes a cascade of oxidative damages to neurons and eventually leads to neuronal death. In this study, salidroside (Sald), an active compound isolated from a traditional Chinese medicinal plant, Rhodiola rosea L., was investigated to assess its protective effects and the underlying mechanisms against Abeta-induced oxidative stress in SH-SY5Y human neuroblastoma cells. Abeta(25-35)-induced neuronal toxicity was characterized by the decrease of cell viability, the release of lactate dehydrogenase (LDH), morphological alterations, neuronal DNA condensation, and the cleavage of poly(ADP-ribose) polymerase (PARP) by activated caspase-3. Pretreatment with salidroside markedly attenuated Abeta(25-35)-induced loss of cell viability and apoptosis in a dose-dependent manner. The mechanisms of salidroside protected neurons from oxidative stress included the induction of antioxidant enzymes, thioredoxin (Trx), heme oxygenase-1 (HO-1), and peroxiredoxin-I (PrxI); the downregulation of pro-apoptotic protein Bax and the upregulation of anti-apoptotic protein Bcl-X(L). Furthermore, salidroside dose-dependently restored Abeta(25-35)-induced loss of mitochondrial membrane potential (MMP) as well as suppressed the elevation of intracellular reactive oxygen species (ROS) level. It was also observed that Abeta(25-35) stimulated the phosphorylation of mitogen-activated protein (MAP) kinases, including c-Jun NH(2)-terminal kinase (JNK) and p38 MAP kinase, but not extracellular signal-regulated kinase1/2 (ERK1/2). Salidroside inhibited Abeta(25-35)-induced phosphorylation of JNK and p38 MAP kinase, but not ERK1/2. These results suggest that salidroside has protective effects against Abeta(25-35)-induced oxidative stress, which might be a potential therapeutic agent for treating or preventing neurodegenerative diseases.
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PMID:Neuroprotective effects of salidroside against beta-amyloid-induced oxidative stress in SH-SY5Y human neuroblastoma cells. 2061 44


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