Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P05412 (c-Jun)
 11,453 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We previously reported that antisense c-jun suppressed apoptosis induced by serum deprivation in F-MEL cells. To elucidate the molecular mechanisms responsible for this suppression of apoptosis we investigated the activities and protein expression of antioxidant materials in the cell under serum deprivation. In the parental F-MEL cells enzyme activities of catalase, glutathione S-transferase (GST), and glutathione peroxidase (GPx) increased to reach the maximum at 24-72 h after removal of serum and then decreased to initial levels or a little less. Superoxide dismutase (SOD) maintained the initial level for 72 h and increased 1.5- to 2-fold at 96 h. Glutathione (GSH) levels increased at 24 h and then dropped significantly to one-third the initial level. On the other hand, in c-junAS (+) cells, in which antisense c-jun was expressed and c-Jun protein expression was reduced to undetectable level. We found 1.9-, 2.7-, 4.8-, and 15. 8-fold increase in the activities of catalase, GST, SOD, and GPx, respectively, at 96 h. GSH maintained almost the same level as the initial. Enhancement of these enzyme activities in c-junAS (+) cells was induced under serum deprivation. Western blottings for catalase, GST, and SOD also showed enhanced increase in protein expression, supporting the increase in enzyme activities. Cellular peroxide level under serum deprivation was monitored by flow cytometry using DCFH-DA as a probe. We found that the peroxide level increased at 24 h and then decreased at 72 and 96 h in c-junAS (+) cells, and reduction of the peroxide level coincided with an increase in antioxidant enzyme activities. These results indicate that antioxidant materials such as catalase, GST, SOD, GPx, and GSH are induced by serum deprivation when c-jun expression is inhibited in F-MEL cells. The link between inhibition of c-jun expression and enhancement of cellular antioxidant defense is discussed.
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PMID:Inhibition of c-Jun expression induces antioxidant enzymes under serum deprivation. 1066 16

Glutathione S-transferases (GSTs, EC 2.5.1.18) belong to a large family of functionally different enzymes that catalyze the S-conjugation of glutathione with a wide variety of electrophilic compounds including carcinogens and anticancer drugs. Drug resistance may result from reduction in apoptosis of neoplastic cells when exposed to antineoplastic drugs. The c-Jun N-terminal Kinase (JNK) belongs to the family of stress kinases and has been shown to be required for the maximal induction of apoptosis by DNA-damaging agents. Recently, an inhibition of JNK activity by GST P1-1, which was reversed by polymerization induced by oxidative stress, has been reported in 3T3-4A mouse fibroblast cell lines. The finding that GST P1-1 might inhibit JNK activity and that it is frequently highly expressed in tumor tissues suggests its possible implication in "apoptosis resistance" during antineoplastic therapy. We investigated the modulation of GST P1-1 during apoptosis in a neoplastic T-cell line (Jurkat) induced by hydrogen peroxide and etoposide. Apoptosis was paralleled by the appearance of a dimeric form of GST P1-1 on western blotting, associated with an increase in the Km(GSH) and a reduction in GST P1-1 specific activity toward 1-chloro-2,4-dinitrobenzene, which reached statistical significance only in H(2)O(2)-treated cells. Our data seem to suggest that H(2)O(2) and etoposide may partly act through a process of partial inactivation of the GST P1-1, possibly involving the "G" site in the process of dimerization, and thus favoring programmed cell death.
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PMID:Modulation of GST P1-1 activity by polymerization during apoptosis. 1077 20

The development of an oxidant/antioxidant imbalance in lung inflammation may activate redox-sensitive transcription factors such as nuclear factor-kappa B (NF-kappa B) and activator protein-1 (AP-1), which regulate the genes for proinflammatory mediators and protective antioxidant genes. GSH, a ubiquitous tripeptide thiol, is a vital intra- and extracellular protective antioxidant against oxidative stress, which plays a key role in the control of proinflammatory processes in the lungs. The rate-limiting enzyme in GSH synthesis is gamma-glutamylcysteine synthetase (gamma-GCS), which consists of a catalytic heavy and a regulatory light subunit. The promoter regions of the human gamma-GCS subunits contain AP-1, NF-kappa B, and antioxidant response elements and are regulated by oxidants, growth factors, inflammatory cytokine tumor necrosis factor-alpha (TNF-alpha), and anti-inflammatory agent (dexamethasone) in lung cells. TNF-alpha depletes intracellular GSH, concomitant with an increase in oxidised glutathione levels in alveolar epithelial cells. TNF-alpha also induces the activation of NF-kappa B and AP-1 and the subsequent increase in gamma-GCS heavy subunit transcription in these cells. Dexamethasone depleted both basal and TNF-alpha-stimulated GSH levels by down-regulating the gamma-GCS-heavy subunit transcription via a mechanism involving AP-1 (c-Jun). The existence of this fine tuning between the redox GSH levels and the activation of transcription factors may determine the balance of transcription for proinflammatory and antioxidant gamma-GCS genes in inflammation. More studies are required to understand the signalling mechanism of the redox regulation of NF-kappa B and AP-1 and gene transcription in inflammation. This could lead to the development of therapeutic strategies based on the pharmacological manipulation of the production of this important antioxidant in inflammation.
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PMID:Regulation of nuclear factor-kappa B, activator protein-1, and glutathione levels by tumor necrosis factor-alpha and dexamethasone in alveolar epithelial cells. 1100 40

Oxidative stress has been involved in various neurological disorders and, in the central nervous system, astrocytes represent the cell type that contributes to neuroprotection via glutathione (GSH) metabolism, GSH-metabolizing enzymes like gamma-glutamyltransferase (GGT), and apoE secretion. In this study, using IL-1beta, a proinflammatory and prooxidant cytokine that is increased in numerous pathological situations, cells of astrocytoma cell line U373-MG were exposed to an oxidative stress, leading to c-Jun and c-Fos activation. IL-1beta decreased both GGT activity and intracellular GSH content and increased apoE secretion, initiating astroglial response to injury. We observed that antioxidants inhibit IL-1beta effects on c-Jun and c-Fos proteins, GGT activity and the GSH pool but not on apoE secretion. Our results allow us to conclude that neurological disorders associated with an IL-1beta-induced oxidative stress could be, at least experimentally, reversible in the presence of one antioxidant, N-acetylcysteine.
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PMID:U373-MG response to interleukin-1beta-induced oxidative stress. 1103 59

Protein-calorie malnutrition (PCM), a major global health problem, arises during protein and/or energy deficit due to disease and nutritional inadequacy. To date, cellular adaptive responses and gene expression associated with PCM remain poorly understood. In view of the primary role of the liver in energy conversion, the present study was designed to investigate changes in hepatic morphology and molecular alterations during PCM. PCM caused marked decreases in the cytoplasmic eosinophilic content and nuclear shrinkage in the hepatocytes with a decrease in glutathione content. The nuclear activator protein-1 (AP-1) complex was activated in the liver of PCM rats. AP-1-binding activity of nuclear extracts produced from PCM rats was reduced by the presence of anti-c-Jun antibody. Microsomal epoxide hydrolase (mEH), a phase II detoxifying enzyme, was 4-fold induced, with a 20-fold increase in the mRNA level during PCM. In contrast to the PCM-induced changes in hepatic morphology, PCM rats supplemented with cysteine showed an increase in the GSH level and well-preserved hepatic structures with mild fat degeneration. Cysteine supplementation inhibited the activation of AP-1 and the induction of mEH in PCM rats. These results provided evidence: (i) that PCM alters liver morphology with a decrease in the glutathione level; (ii) that cysteine may serve as a key element responsible for preserving hepatic morphology and maintaining the glutathione level; and (iii) that cysteine was active in preventing the activation of AP-1 and mEH induction in the liver during PCM.
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PMID:Prevention of c-Jun/activator protein-1 activation and microsomal epoxide hydrolase induction in the rat liver by cysteine during protein-calorie malnutrition. 1113 4

The role of p44/42 mitogen-activated protein kinase (MAPK), p38, and c-Jun NH(2)-terminal kinase (JNK) in tumor necrosis factor (TNF)-alpha-induced cyclooxygenase (COX)-2 expression was studied in NCI-H292 epithelial cells. TNF-alpha-mediated COX-2 expression and COX-2 promoter activity were inhibited by the MAPK kinase inhibitor PD98059 or the p38 inhibitor SB203580. Treatment of cells for 10 min with TNF-alpha resulted in activation of p44/42 MAPK, p38, and JNK. C2-ceramide (a cell-permeable ceramide analog), bacterial neutral sphingomyelinase (Smase; an enzyme that degrades sphingomyelin to ceramide), and N-oleoylethanolamine (a ceramidase inhibitor) all induced activation of MAPKs, COX-2 expression, nuclear factor (NF)-kappaB DNA-protein binding, and COX-2 promoter activity. The inactive analog, dihydro-C2-ceramide, had no effect. SMase- or C2-ceramide-induced COX-2 expression and COX-2 promoter activity were also inhibited by PD98059 or SB203580. Glutathione, a neutral SMase inhibitor, attenuated TNF-alpha- or SMase-induced activation of MAPKs, COX-2 expression, and COX-2 promoter activity. TNF-alpha- or C2-ceramide-induced COX-2 promoter activity was inhibited by the dominant negative mutant of extracellular signal-regulated kinase 2, p38, JNK, IkappaB kinase (IKK)1, or IKK2. IKK activity was stimulated by either TNF-alpha or C2-ceramide, and these effects were inhibited by PD98059 or SB203580. All these results suggest that, in NCI-H292 epithelial cells, activation of MAPKs by ceramide contributes to the TNF-alpha signaling that occurs downstream of neutral SMase activation and results in the stimulation of IKK1/2, and NF-kappaB in the COX-2 promoter, followed by initiation of COX-2 expression.
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PMID:Tumor necrosis factor-alpha-induced cyclooxygenase-2 expression via sequential activation of ceramide-dependent mitogen-activated protein kinases, and IkappaB kinase 1/2 in human alveolar epithelial cells. 1117 44

Adenovirus gene therapy is a promising tool in the clinical treatment of many genetic and acquired diseases. However, it has also caused pathogenic effects in organs such as the liver. The redox-sensitive transcription factors AP-1 and NF-kappaB have been implicated in these effects. To study the mechanisms of adenovirus-mediated AP-1 and NF-kappaB activation and the possible involvement of oxidative stress in adenovirus transduction, rats were injected with either replication-defective recombinant adenovirus with DNA containing the cytomegalovirus promoter region only (AdCMV), adenovirus containing human manganese-containing superoxide dismutase (MnSOD) cDNA (AdMnSOD), or vehicle. Compared to vehicle and AdCMV transduction, MnSOD gene transfer yielded a fivefold increase in liver MnSOD activity 7 days postinjection. Gel shift assay showed that AdCMV transduction induced DNA binding activity for AP-1 but not NF-kappaB. MnSOD overexpression abolished this activation. Western blotting analysis of c-Fos and c-Jun suggested that up-regulation of c-fos and c-jun gene expression does not directly contribute to the induction of AP-1 activation. Glutathione/glutathione disulfide ratios were decreased by adenovirus transduction and restored by MnSOD overexpression. The AP-1 binding activity that was induced by AdCMV was decreased by immunoprecipitation of Ref-1 protein. Ref-1 involvement was confirmed by restoration of AP-1 binding activity after the immunoprecipitated Ref-1 protein had been added back. AP-1 DNA binding activity was also elevated in control and AdMnSOD-injected rats after addition of the immunoprecipitated Ref-1 protein. These data indicate that cellular transduction by recombinant adenovirus stimulates AP-1 DNA binding activity. Furthermore, our results suggest that MnSOD overexpression decreases AP-1 DNA binding activity by regulating intracellular redox status, with the possible involvement of Ref-1 in this redox-sensitive pathway.
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PMID:Redox regulation of adenovirus-induced AP-1 activation by overexpression of manganese-containing superoxide dismutase. 1173

Cellular responses to xenobiotic-induced stress can signal proliferation, differentiation, homeostasis, apoptosis, or necrosis. To better understand the underlying molecular mechanisms after exposure to xenobiotics or drugs, we studied the signal transduction pathways, the mitogen-activated protein kinase (MAPK), and the basic leucine zipper transcription factor Nrf2, activated by different agents in the induction of Phase II drug metabolizing enzymes (DMEs). The MAPKs, characterized as proline-directed serine/threonine kinases, are essential components of signaling pathways that convert various extracellular signals into intracellular responses through serial phosphorylation cascades. Once activated, MAPKs can phosphorylate many transcription factors, such as c-Jun, ATF-2, and ultimately lead to changes in gene expression. Two classes of Phase II gene inducers, which are also cancer chemopreventive agents, were studied: (1) the phenolic antioxidants, namely butylated hydroxyanisole (BHA) and its active de-methylated metabolite t-butylhydroquinone (tBHQ), and phenolic flavonoids such as green tea polyphenols (GTP) and (-)-epigallocatechin-3-gallate (EGCG); and (2) the naturally occurring isothiocyanates, namely phenethyl isothiocyanate (PEITC), and sulforaphane. BHA and tBHQ are both well-known phenolic antioxidants used as food preservatives, and strongly activate c-Jun N-terminal kinase 1 (JNK1), extracellular signal-regulated protein kinase 2 (ERK2), or p38, in a time- and dose-dependent fashion. Free radical scavengers N-acetyl-L-cysteine (NAC), or glutathione (GSH), inhibited ERK2 activation and, to a much lesser extent, JNK1 activation by BHA/tBHQ, implicating the role of oxidative stress. Under conditions where MAPKs were activated, BHA or GTP also activated ARE/EpRE (antioxidant/electrophile response element), with the induction of Phase II genes such as NQO. Transfection studies with various cDNAs encoding wild-type or dominant-negative mutants of MAPKs and/or transcription factor Nrf2, substantially modulated ARE-mediated luciferase reporter activity in the presence or absence of phenolic compounds. Other phytochemicals including PEITC, and sulforaphane, also differentially regulated the activities of MAPKs, Nrf2, and ARE-mediated luciferase reporter gene activity and Phase II enzyme induction. A model is proposed where these xenobiotics (BHA, tBHQ, GTP, EGCG, PEITC, sulforaphane) activate the MAPK pathway via an electrophilic-mediated stress response, leading to the transcription activation of Nrf2/Maf heterodimers on ARE/EpRE enhancers, with the subsequent induction of cellular defense/detoxifying genes including Phase II DMEs, which may protect the cells against toxic environmental insults and thereby enhance cell survival. The studies of these signaling pathways may yield insights into the fate of cells upon exposure to xenobiotics.
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PMID:Induction of xenobiotic enzymes by the MAP kinase pathway and the antioxidant or electrophile response element (ARE/EpRE). 1176 69

The mechanisms underlying hepatocyte sensitization to tumor necrosis factor-alpha (TNF-alpha)-mediated cell death remain unclear. Increases in hepatocellular oxidant stress such as those that occur with hepatic overexpression of cytochrome P-450 2E1 (CYP2E1) may promote TNF-alpha death. TNF-alpha treatment of hepatocyte cell lines with differential CYP2E1 expression demonstrated that overexpression of CYP2E1 converted the hepatocyte TNF-alpha response from proliferation to apoptotic and necrotic cell death. Death occurred despite the presence of increased levels of nuclear factor-kappaB transcriptional activity and was associated with increased lipid peroxidation and GSH depletion. CYP2E1-overexpressing hepatocytes had increased basal and TNF-alpha-induced levels of c-Jun NH(2)-terminal kinase (JNK) activity, as well as prolonged JNK activation after TNF-alpha stimulation. Sensitization to TNF-alpha-induced cell death by CYP2E1 overexpression was inhibited by antioxidants or adenoviral expression of a dominant-negative c-Jun. Increased CYP2E1 expression sensitized hepatocytes to TNF-alpha toxicity mediated by c-Jun and overwhelming oxidative stress. The chronic increase in intracellular oxidant stress created by CYP2E1 overexpression may serve as a mechanism by which hepatocytes are sensitized to TNF-alpha toxicity in liver disease.
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PMID:Increased cytochrome P-450 2E1 expression sensitizes hepatocytes to c-Jun-mediated cell death from TNF-alpha. 1180 47

The apoptotic cell death of Jurkat cells due to Cd(2+) toxicity was studied by fluorescence microscopic observation and DNA fragmentation assaying. It was suggested that the apoptotic response to Cd(2+) was less clear than that to a typical apoptosis inducer, ultraviolet light (254 nm). Examination of MAP kinase phosphorylation (p38, JNKs, and c-Jun) due to Cd(2+) toxicity indicated that the phosphorylation was very slowly activated (4 h after stimulation), while UV light could activate the phosphorylation immediately. Therefore, it was suggested that Cd(2+) may not be a typical apoptosis inducer. Antioxidants [glutathione (GSH) and N-acetylcysteine (NAC)] could detoxify Cd(2+), indicating that the toxicity is a kind of oxidative stress. The detoxification effect of antioxidants showed cooperation with Bcl-2, suggesting that Cd(2+)-treatment causes diversified toxic signals including oxidative stress. On the addition of a plant-specific peptide, phytochelatin [PC(7), (gammaGlu-Cys)(7)-Gly], to the medium, the detoxification of Cd(2+) and cooperation with Bcl-2 were more intense than in the cases of GSH and NAC. Using an appropriate vector, a PC synthase gene was transferred from Arabidopsis thaliana to the Jurkat cell. The transfectant exhibited resistance to Cd(2+) and production of plant-specific PC (PC(2-6)).
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PMID:Cellular toxicity of cadmium ions and their detoxification by heavy metal-specific plant peptides, phytochelatins, expressed in Mammalian cells. 1182 Sep 37


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