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Results for “Apoptosis Inducing Factor”

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PubMed2003

Cyclosporin A prevents calpain activation despite increased intracellular calcium concentrations, as well as translocation of apoptosis-inducing factor, cytochrome c and caspase-3 activation in neurons exposed to transient hypoglycemia.

Blockade of mitochondrial permeability transition protects against hypoglycemic brain damage. To study the mechanisms downstream from mitochondria that may cause neuronal death, we investigated the effects of cyclosporin A on subcellular localization of apoptosis-inducing factor and cytochrome c, activation of the cysteine proteases calpain and caspase-3, as well as its effect on brain extracellular calcium concentrations. Redistribution of cytochrome c occurred at 30 min of iso-electricity, whereas translocation of apoptosis-inducing factor to nuclei occurred at 30 min of recovery following 30 min of iso-electricity. Active caspase-3 and calpain-induced fodrin breakdown products were barely detectable in the dentate gyrus and CA1 region of the hippocampus of rat brain exposed to 30 or 60 min of insulin-induced hypoglycemia. However, 30 min or 3 h after recovery of blood glucose levels, fodrin breakdown products and active caspase-3 markedly increased, concomitant with a twofold increase in caspase-3-like enzymatic activity. When rats were treated with neuroprotective doses of cyclosporin A, but not with FK 506, the redistribution of apoptosis-inducing factor and cytochrome c was reduced and fodrin breakdown products and active caspase-3 immuno-reactivity was diminished whereas the extracellular calcium concentration was unaffected. We conclude that hypoglycemia leads to mitochondrial permeability transition which, upon recovery of energy metabolism, mediates the activation of caspase-3 and calpains, promoting cell death.

Animals↗
PubMed2004

Nuclear translocation of apoptosis-inducing factor after focal cerebral ischemia.

Signaling cascades associated with apoptosis contribute to cell death after focal cerebral ischemia. Cytochrome c release from mitochondria and the subsequent activation of caspases 9 and 3 are critical steps. Recently, a novel mitochondrial protein, apoptosis-inducing factor (AIF), has been implicated in caspase-independent programmed cell death following its translocation to the nucleus. We, therefore, addressed the question whether AIF also plays a role in cell death after focal cerebral ischemia. We detected AIF relocation from mitochondria to nucleus in primary cultured rat neurons 4 and 8 hours after 4 hours of oxygen/glucose deprivation. In ischemic mouse brain, AIF was detected within the nucleus 1 hour after reperfusion after 45 minutes occlusion of the middle cerebral artery. AIF translocation preceded cell death, occurred before or at the time when cytochrome c was released from mitochondria, and was evident within cells showing apoptosis-related DNA fragmentation. From these findings, we infer that AIF may be involved in neuronal cell death after focal cerebral ischemia and that caspase-independent signaling pathways downstream of mitochondria may play a role in apoptotic-like cell death after experimental stroke.

Animals↗
PubMed2004

MGLuR5 activation reduces beta-amyloid-induced cell death in primary neuronal cultures and attenuates translocation of cytochrome c and apoptosis-inducing factor.

Activation of metabotropic glutamate receptor 5 (mGluR5) has been shown to reduce caspase-dependent apoptosis in primary neuronal cultures induced by staurosporine and etoposide. beta-Amyloid (Abeta)-induced neurotoxicity in culture appears to be in part caspase mediated. In the present studies the effects of treatment with an mGluR5 agonist or antagonist on Abeta-induced neuronal apoptosis were examined in rat cortical neuronal cultures. Pretreatment with the selective mGluR5 agonist (RS)-2-chloro-5-hydroxyphenylglycine (CHPG) markedly reduced the number of apoptotic cells after exposure to Abeta (25-35), as well as associated LDH release. Blockade of mGluR5 by the selective antagonist, 2-methyl-6-(phenylethynyl)pyridine (MPEP) attenuated these effects of CHPG. A similar neuroprotective effect of mGluR5 activation by CHPG was observed in cultures treated with full-length Abeta peptide (1-42). CHPG attenuated Abeta (25-35)-induced cytochrome c release and decreased levels of active caspase-3 protein. CHPG also reduced translocation of apoptosis-inducing factor (AIF) induced by Abeta (25-35). Thus, mGluR5 activation limits the release of mitochondrial proteins associated with induction of both caspase-dependent and -independent apoptosis.

Amyloid beta-Peptides↗
PubMed1998

Keratinocyte growth factor protects murine hepatocytes from tumor necrosis factor-induced apoptosis in vivo and in vitro.

Keratinocyte growth factor (KGF) promotes epithelial growth and differentiation and has potent effects on the liver. The coinjection of lipopolysaccharide (LPS) and D-galactosamine (GalN) results in hepatic failure in mice. Mechanistically, LPS-induced tumor necrosis factor (TNF) triggers hepatocyte apoptosis, which is enhanced by GalN-arrested transcription. Similarly, the combination of TNF and actinomycin D (ActD) causes hepatocyte apoptosis in vitro. We studied the effect of KGF on LPS and GalN-induced hepatic failure in vivo and on TNF- and ActD-induced hepatocyte apoptosis in vitro, where it was compared with those of hepatic growth factor (HGF) and epidermal growth factor (EGF). Mice treated with human recombinant KGF (1 mg/kg subcutaneously) 24 hours before intraperitoneal coinjection of LPS and GalN sustained prolonged survival compared with control mice, although overall mortality was not changed. The counts of apoptotic hepatocytes, serum alanine and aspartate transaminases, and DNA fragments in the cytosolic fraction of liver homogenates were higher in control mice than in treated mice 6 hours after LPS and GalN coinjection, before any mortality occurred. In vitro, hepatocytes pretreated with KGF exhibited reduced TNF- and ActD-induced cell damage and DNA fragmentation, similar to hepatocytes pretreated with HGF and EGF. In conclusion, KGF prolongs survival during LPS- and GalN-induced hepatic failure by temporarily protecting hepatocytes against apoptosis. It also protects hepatocytes in vitro against TNF- and ActD-induced apoptosis.

Animals↗
PubMed2001

Heat-shock protein 70 antagonizes apoptosis-inducing factor.

Heat-shock protein 70 (Hsp70) has been reported to block apoptosis by binding apoptosis protease activating factor-1 (Apaf-1), thereby preventing constitution of the apoptosome, the Apaf-1/cytochrome c/caspase-9 activation complex [1,2]. Here we show that overexpression of Hsp70 protects Apaf-1-/- cells against death induced by serum withdrawal, indicating that Apaf-1 is not the only target of the anti-apoptotic action of Hsp70. We investigated the effect of Hsp70 on apoptosis mediated by the caspase-independent death effector apoptosis inducing factor (AIF), which is a mitochondrial intermembrane flavoprotein [3,4]. In a cell-free system, Hsp70 prevented the AIF-induced chromatin condensation of purified nuclei. Hsp70 specifically interacted with AIF, as shown by ligand blots and co-immunoprecipitation. Cells overexpressing Hsp70 were protected against the apoptogenic effects of AIF targeted to the extramitochondrial compartment. In contrast, an anti-sense Hsp70 complementary DNA, which reduced the expression of endogenous Hsp70, increased sensitivity to the lethal effect of AIF. The ATP-binding domain of Hsp70 seemed to be dispensable for inhibiting cell death induced by serum withdrawal, AIF binding and AIF inhibition, although it was required for Apaf-1 binding. Together, our data indicate that Hsp70 can inhibit apoptosis by interfering with target proteins other than Apaf-1, one of which is AIF.

Animals↗
PubMed2005

Metalloporphyrin-based superoxide dismutase mimic attenuates the nuclear translocation of apoptosis-inducing factor and the subsequent DNA fragmentation after permanent focal cerebral ischemia in mice.

BACKGROUND AND PURPOSE: Recently, apoptosis- inducing factor (AIF), a mitochondrial proapoptotic protein, and its nuclear translocation have been reported in caspase-independent neuronal apoptosis. In this study, we investigated the contribution of reactive oxygen species (ROS) to the nuclear translocation of AIF and the subsequent DNA fragmentation after permanent focal cerebral ischemia (pFCI) using manganese tetrakis (4-benzoic acid) porphyrin (MnTBAP), which mimics mitochondrial superoxide dismutase. METHOD: Adult male ICR mice were subjected to pFCI by intraluminal suture blockade of the middle cerebral artery. Immunohistochemistry and Western blot analysis were performed. Large-scale DNA fragmentation was evaluated by pulse field gel electrophoresis, and apoptotic cell death was quantified. MnTBAP was injected into the ventricle to determine whether the removal of ROS contributes to AIF translocation and the subsequent DNA fragmentation. RESULTS: Western blot analysis showed that the nuclear translocation of AIF occurred as early as 2 hours after pFCI. AIF translocation was not blocked by a pan-caspase inhibitor. MnTBAP-treated mice had attenuated AIF translocation and blocked large-scale DNA fragmentation. Caspase-3 activity was similarly inhibited between the pan-caspase inhibitor- and MnTBAP-treated mice, but the amount of apoptosis-associated DNA fragmentation in the MnTBAP-treated mice was less than in the pan-caspase inhibitor-treated mice (P<0.001). CONCLUSIONS: These results suggest that the MnTBAP, a mitochondrial O2- scavenger, may attenuate the caspase-independent nuclear translocation of AIF after pFCI and subsequent apoptosis-associated DNA fragmentation.

Animals↗
PubMed2003

HSP72 inhibits apoptosis-inducing factor release in ATP-depleted renal epithelial cells.

Inhibition of the mitochondrial release and nuclear translocation of apoptosis-inducing factor (AIF) by heat stress protein (HSP)72 may ameliorate apoptosis in renal epithelial cells exposed to a metabolic inhibitor. To evaluate this hypothesis, cells were transiently exposed to 5 mM sodium cyanide in the absence of medium glucose, a maneuver known to induce apoptosis. ATP depletion for 1-2 h resulted in the progressive accumulation of mitochondrial AIF in the cytosol of samples obtained by selectively permeabilizing the plasma membrane with digitonin. During recovery from ATP depletion, time-dependent nuclear AIF accumulation (but not cytochrome c, an F0F1 ATP synthase subunit, or talin) was observed in isolated nuclei. Nuclear AIF accumulation was associated with peripheral chromatin condensation and DNA degradation. Prior heat stress (HS) significantly reduced AIF leakage into the cytosol, decreased nuclear accumulation of AIF, and inhibited DNA degradation. HS also increased the interaction between AIF and HSP72 detected by immunoprecipitation. In ATP depleted cells, selective overexpression of human HSP72 reduced the leakage of mitochondrial AIF in a dose-dependent manner (r = 0.997). This study suggests that mitochondrial membrane injury and subsequent AIF release contribute to nuclear injury and apoptosis in ATP-depleted renal cells. HSP72, an antiapoptotic protein, inhibits cell injury in part by preventing mitochondrial AIF release and perhaps by decreasing its nuclear accumulation.

Adenosine Triphosphate↗
PubMed2003

Bisphenol A diglycidyl ether-induced apoptosis involves Bax/Bid-dependent mitochondrial release of apoptosis-inducing factor (AIF), cytochrome c and Smac/DIABLO.

(1) Bisphenol A diglycidyl ether (BADGE) is a peroxisome proliferator-activated receptor-gamma (PPAR-gamma) antagonist, which is able to induce apoptosis in tumor cells independently of PPAR-gamma in caspase-dependent and -independent manners. Additionally, BADGE promotes TRAIL-induced apoptosis. (2) We report that BADGE activates via Bax and caspases-2 and -8 both the intrinsic and extrinsic apoptotic pathways using Bid as a shunt. (3) BADGE stimulates the mitochondrial release of apoptosis-inducing factor (AIF), cytochrome c and second mitochondria-derived activator of caspase/direct IAP-binding protein with low pl (Smac/DIABLO). The release of cytochrome c could not be blocked by inhibitors of caspases-3, -8 and -9 indicating that BADGE acts upstream of caspases-3 and -9 and does not involve caspase-8 to release cytochrome c. (4) While the caspase-independent apoptotic effect might be mediated by AIF, the sensitizing effect of BADGE against other apoptotic substances is most likely mediated by the X-linked inhibitor of apoptosis inhibitor Smac/DIABLO. (5) Our data suggest that BADGE or BADGE derivatives could represent promising substances for the treatment of neoplasms improving the antitumoral activity of TRAIL.

Apoptosis↗
PubMed2006

Induction of apoptosis in renal cell carcinoma by reactive oxygen species: involvement of extracellular signal-regulated kinase 1/2, p38delta/gamma, cyclooxygenase-2 down-regulation, and translocation of apoptosis-inducing factor.

Renal cell carcinoma (RCC) is the most common malignancy of the kidney. Unfortunately, RCCs are highly refractory to conventional chemotherapy, radiation therapy, and even immunotherapy. Thus, novel therapeutic targets need to be sought for the successful treatment of RCCs. We now report that 6-anilino-5,8-quinolinequinone (LY83583), an inhibitor of cyclic GMP production, induced growth arrest and apoptosis of the RCC cell line 786-0. It did not prove deleterious to normal renal epithelial cells, an important aspect of chemotherapy. To address the cellular mechanism(s), we used both genetic and pharmacological approaches. LY83583 induced a time- and dose-dependent increase in RCC apoptosis through dephosphorylation of mitogen-activated protein kinase kinase 1/2 and its downstream extracellular signal-regulated kinases (ERK) 1 and -2. In addition, we observed a decrease in Elk-1 phosphorylation and cyclooxygenase-2 (COX-2) down-regulation. We were surprised that we failed to observe an increase in either c-Jun NH(2)-terminal kinase or p38alpha and -beta mitogen-activated protein kinase activation. In contradiction, reintroduction of p38delta by stable transfection or overexpression of p38gamma dominant negative abrogated the apoptotic effect. Cell death was associated with a decrease and increase in Bcl-x(L) and Bax expression, respectively, as well as release of cytochrome c and translocation of apoptosis-inducing factor. These events were associated with an increase in reactive oxygen species formation. The antioxidant N-acetyl l-cysteine, however, opposed LY83583-mediated mitochondrial dysfunction, ERK1/2 inactivation, COX-2 down-regulation, and apoptosis. In conclusion, our results suggest that LY83583 may represent a novel therapeutic agent for the treatment of RCC, which remains highly refractory to antineoplastic agents. Our data provide a molecular basis for the anticancer activity of LY83583.

Aminoquinolines↗
PubMed2005

Apoptosis-inducing factor is a key factor in neuronal cell death propagated by BAX-dependent and BAX-independent mechanisms.

Mitochondria release proteins that propagate both caspase-dependent and caspase-independent cell death pathways. AIF (apoptosis-inducing factor) is an important caspase-independent death regulator in multiple neuronal injury pathways. Presently, there is considerable controversy as to whether AIF is neuroprotective or proapoptotic in neuronal injury, such as oxidative stress or excitotoxicity. To evaluate the role of AIF in BAX-dependent (DNA damage induced) and BAX-independent (excitotoxic) neuronal death, we used Harlequin (Hq) mice, which are hypomorphic for AIF. Neurons carrying double mutations for Hq/Apaf1-/- (apoptosis proteases-activating factor) are impaired in both caspase-dependent and AIF-mediated mitochondrial cell death pathways. These mutant cells exhibit extended neuroprotection against DNA damage, as well as glutamate-induced excitotoxicity. Specifically, AIF is involved in NMDA- and kainic acid- but not AMPA-induced excitotoxicity. In vivo excitotoxic studies using kainic acid-induced seizure showed that Hq mice had significantly less hippocampal damage than wild-type littermates. Our results demonstrate an important role for AIF in both BAX-dependent and BAX-independent mechanisms of neuronal injury.

Animals↗
PubMed2004

Poly(ADP-ribose) polymerase inhibition protect neurons and the white matter and regulates the translocation of apoptosis-inducing factor in stroke.

Focal cerebral ischemia activates the nuclear protein poly(ADP-ribose) polymerase (PARP). Apoptosis-inducing factor (AIF) is a flavoprotein that is normally confined to the mitochondria, but translocates to the nucleus, as shown by in vitro models of neuronal injury. Using INO-1001, a novel potent inhibitor of PARP, we determined the role of PARP activation in the process of AIF translocation in a rat model of focal cerebral ischemia. The potency of INO-1001 as a PARP inhibitor and its cytoprotective potential in oxidant-challenged human neuronal SK-N-MC cells was first confirmed in vitro. PARP inhibition markedly reduced infarct size and improved neurological status in both transient and permanent models of MCA occlusion in Sprague-Dawley rats, with a therapeutic window of 6 h and 2 h in the transient and permanent ischemia models, respectively. The PARP inhibitor reduced the accumulation of poly(ADP-ribose) in the ischemic/reperfused hemisphere and reduced the accumulation of APP in the white matter of the affected hemisphere, consistently with protection against neuronal necrosis and axonal damage, respectively. Immunohistochemical analysis showed the appearance of AIF labeling in neuronal nuclei of the border zone ischemic area in the striatum after stroke. Cytoplasmatic (axonal) AIF staining was significantly diminished in the necrotic core of the striatum, while it was somewhat enhanced at the borderline ischemic territories of the white matter. Inhibition of PARP with INO-1001 reshifted the location of the apoptotic marker to the axons in the ipsilateral striatum. Thus, PARP inhibition is neuroprotective and regulates the ischemic nuclear translocation of AIF in stroke.

Animals↗
PubMed2006

Heat shock protein 70 inhibits the nuclear import of apoptosis-inducing factor to avoid DNA fragmentation in TF-1 cells during erythropoiesis.

Loss of mitochondrial membrane potential (DeltaPsi(m)) and release of AIF (apoptosis-inducing factor) from mitochondria are key steps in apoptosis. In TF-1 model, DeltaPsi(m) was depolarized with AIF release during erythroid development. Yet, no DNA fragmentation was observed. When DeltaPsi(m) depolarization had been blocked, erythropoiesis was suppressed. Interestingly, heat shock protein 70 (Hsp70) was found transiently upregulated during depolarization and it retained AIF in the cytosol to avoid DNA damages. When Hsp inhibitor was added, DNA fragmentation occurred. We show this mechanism for the first time in erythropoiesis how cells with DeltaPsi(m) depolarization and AIF release escape apoptosis.

Apoptosis Inducing Factor↗
PubMed2006

Apoptosis-inducing factor mediates poly(ADP-ribose) (PAR) polymer-induced cell death.

Apoptosis-inducing factor (AIF), a mitochondrial oxidoreductase, is released into the cytoplasm to induce cell death in response to poly(ADP-ribose) (PAR) polymerase-1 (PARP-1) activation. How PARP-1 activation leads to AIF release is not known. Here we identify PAR polymer as a cell death signal that induces release of AIF. PAR polymer induces mitochondrial AIF release and translocation to the nucleus. PAR glycohydrolase, which degrades PAR polymer, prevents PARP-1-dependent AIF release. Cells with reduced levels of AIF are resistant to PARP-1-dependent cell death and PAR polymer cytotoxicity. These results reveal PAR polymer as an AIF-releasing factor that plays important roles in PARP-1-dependent cell death.

Animals↗
PubMed2004

Detection of apoptosis-inducing factor in involuting mammary tissue by immunoelectron microscopy.

Immunoelectron microscopy was used to study the subcellular localisation of apoptosis-inducing factor (AIF) in involuting bovine mammary tissue. AIF was detected using a polyclonal antibody and secondary anti-rabbit antibody conjugated to colloidal gold particles under optimised conditions. The polyclonal antibody appeared specific for the bovine antigen and immunocytological examination identified specific localisation of AIF in mitochondria, cytoplasm and nucleus of mammary epithelial cells in involuting mammary tissue, suggesting a subcellular translocation in cells undergoing apoptosis.

Animals↗
PubMed2005

Downregulation of apoptosis-inducing factor in harlequin mutant mice sensitizes the myocardium to oxidative stress-related cell death and pressure overload-induced decompensation.

Apoptosis-inducing factor (AIF), or programmed cell death 8 (Pdcd8), is a highly conserved, ubiquitous flavoprotein localized in the mitochondrial intermembrane space. In vivo, AIF provides protection against neuronal apoptosis induced by oxidative stress. Conversely, in vitro, AIF has been demonstrated to have a proapoptotic role when, on induction of the mitochondrial death pathway, AIF translocates to the nucleus where it facilitates chromatin condensation and large scale DNA fragmentation. To determine the role of AIF in myocardial apoptotic processes, we examined cardiomyocytes from an AIF-deficient mouse mutant, Harlequin (Hq). Hq mutant cardiomyocytes demonstrated increased sensitivity to H2O2-induced cell death. Further, Hq hearts subjected to ischemia/reperfusion revealed more cardiac damage and, unlike wild-type mice, the amount of damage increased with the age of the animal. Aortic banding caused enhanced hypertrophy, increased cardiomyocyte apoptotic and necrotic cell death, and accelerated progression toward maladaptive left ventricular remodeling in Hq mutant mice compared with wild-type counterparts. These findings correlated with a reduced capacity of subsarcolemmal mitochondria from Hq mutant hearts to scavenge free radicals. Together, these data demonstrate a critical role for AIF as a cardiac antioxidant in the protection against oxidative stress-induced cell death and development of heart failure induced by pressure overload.

Animals↗
PubMed1998

Protein kinase Cmu downregulation of tumor-necrosis-factor-induced apoptosis correlates with enhanced expression of nuclear-factor-kappaB-dependent protective genes.

Protein kinase Cmu (PKCmu) represents a new subtype of the PKC family characterized by the presence of a pleckstrin homology (PH) domain and an amino-terminal hydrophobic region. In order to analyse the potential role of PKCmu in signal-transduction pathways, stable PKCmu transfectants were established with human and murine cell lines. All transfectants showed a reduced sensitivity to tumor-necrosis-factor (TNF)-induced apoptosis, which correlated with the amount of transgene expressed and with an enhanced basal transcription rate of NF-kappaB-driven genes including the inhibitor of apoptosis protein 2 (cIAP2) and TNF-receptor-associated protein 1 (TRAF1). Sensitivity to apoptosis induced by the lipid mediator ceramide was unchanged in PKCmu transfectants. In support of a PKCmu action on NF-kappaB, we show enhancement and downregulation of TNF-induced expression of a NF-kappaB-dependent reporter gene by transient overexpression of wild-type and kinase-negative mutants of PKCmu, respectively. Interestingly, no significant changes were found in an electrophoretic mobility shift assay, indicative of PKCmu action downstream of IkappaB degradation, probably by modulation of the transactivation capacity of NF-kappaB. The dominant negative action of the kinase-negative mutant further suggest a regulatory role of PKCmu for NF-kappaB-dependent gene expression.

Apoptosis↗
PubMed2006

Immunohistochemical analysis of apoptosis-inducing factor (AIF) expression in gastric carcinomas.

Mounting evidence suggests that both survival and death of cells play an important role in tumorigenesis. Apoptosis-inducing factor (AIF), a mitochondrial protein, plays an important role in the caspase-independent apoptosis. Also, recent studies have demonstrated that AIF has an oxidoreductase function that confers survival on the cells. As the roles of AIF in cancers are largely unknown, it may be important to identify the expression pattern of AIF in cancer tissues. In this study, which aims at defining the role of AIF in gastric tumorigenesis, we analyzed the expression of AIF in 60 gastric adenocarcinomas using immunohistochemistry. AIF expression was detected in the cytoplasm in 42 cases (70%) of gastric carcinoma. We also analyzed AIF expression in early (EGC) and advanced gastric carcinomas (AGC). AIF was expressed in 25 (73%) of 34 intestinal-type cancers and in 17 (65%) of 26 diffuse-type cancers. However, there was no significant difference in AIF expression with respect to the histological subtypes or the depth of invasions, either. In normal gastric mucosal cells, parietal cells, but not other mucosal cells, expressed AIF. Increased expression of AIF in malignant gastric epithelial cells compared to the normal mucosal cells suggests that AIF expression may play a role in gastric tumorigenesis. Also, the data suggest that AIF expression may play a role in the function of the gastric parietal cells.

Adenocarcinoma↗
PubMed1999

Overexpression of gamma-glutamylcysteine synthetase suppresses tumor necrosis factor-induced apoptosis and activation of nuclear transcription factor-kappa B and activator protein-1.

Tumor necrosis factor (TNF) is a highly pleiotropic cytokine whose activity is at least partially regulated by the redox status of the cell. The cellular redox status is controlled primarily by glutathione, a major cellular antioxidant, whose synthesis is regulated by the rate-limiting enzyme gamma-glutamylcysteine synthetase (gamma-GCS). In the present report we investigated the effect of gamma-GCS overexpression on the TNF-induced activation of nuclear transcription factors NF-kappa B and AP-1, stress-activated protein kinase/c-Jun amino-terminal kinase (JNK) and apoptosis. Transfection of cells with gamma-GCS cDNA blocked TNF-induced NF-kappa B activation, cytoplasmic I kappa B alpha degradation, nuclear translocation of p65, and NF-kappa B-dependent gene transcription. gamma-GCS overexpression also completely suppressed NF-kappa B activation induced by phorbol ester and okadaic acid, whereas that induced by H2O2, ceramide, and lipopolysaccharide was minimally affected. gamma-GCS also abolished the activation of AP-1 induced by TNF and inhibited TNF-induced activation of JNK and mitogen-activated protein kinase kinase. TNF-mediated cytotoxicity and activation of caspase-3 were both abrogated in gamma-GCS-overexpressing cells. Overall, our results indicate that most of the pleiotropic actions of TNF are regulated by the glutathione-controlled redox status of the cell.

Animals↗