Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P08758 (annexin V)
 9,383 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The current study characterizes the mechanism by which mercury, a toxic metal, induces death in murine macrophages. The cytotoxic EC(50) of mercury ranged from 62.7 to 81.1 microM by various assays in J774A.1 cultures; accordingly, we employed 70 microM of mercuric chloride in most experiments. Mercury-induced intracellular calcium modulated reactive oxygen species (ROS) production, which resulted in both cell apoptosis and necrosis indicated by annexin V binding and caspase-3 activity, and propidium-iodide binding. Calcium antagonists abolished ROS production. Mercury stimulated p38 mitogen-activated protein kinase (MAPK) and additively stimulated lipopolysaccharide-activated p38. Mercury-activated p38 was decreased by pretreatment of cells with antioxidants, N-acetylcysteine (NAC) and silymarin, indicating that mercury-induced ROS were involved in p38 activation. Mercury increased the expression of tumor necrosis factor alpha (TNFalpha); antioxidants and a specific p38 inhibitor decreased this effect. Pretreatment with antioxidants, p38 inhibitor, and anti-TNFalpha antibody decreased mercury-induced necrosis; however, anti-TNFalpha antibody did not decrease mercury-induced apoptosis. Results suggest that mercury-induced macrophage death is a mix of apoptosis and necrosis employing different pathways. P38-mediated caspase activation regulates mercury-induced apoptosis and p38-mediated TNFalpha regulates necrosis in these cells. Calcium regulates ROS production and mercury-induced ROS modulate downstream p38 that regulates both apoptosis and necrosis.
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PMID:Mercury-induced apoptosis and necrosis in murine macrophages: role of calcium-induced reactive oxygen species and p38 mitogen-activated protein kinase signaling. 1505 Apr 7

Acetaminophen in large doses is well-known as hepatotoxic, and early therapy with N-acetylcysteine is frequently life-saving. However, in later stages of acetaminophen poisoning, treatment with N-acetylcysteine is not always effective. Although some of the pathways of acetaminophen toxicity and the effect of N-acetylcysteine have been elucidated, in depth information on this process is still lacking. Hepatoma-derived HepG2 cultured cells were exposed to acetaminophen (5 and 10 mM), with or without N-acetylcysteine (5 mM), for 24 and 48 hr. For the assessment of oxidative damage, apoptosis and necrosis, we followed redox status, glutathione content, nuclear fragmentation, phosphatidylserine externalization and ultrastructural changes. Variations in Ca2+ level and number of mitochondrial dense granules were also studied. Acetaminophen treatment of HepG2 cells caused oxidative damage and apoptosis. Significant decrease of cellular redox potential and glutathione content were time- and concentration-dependent. The protective effect of N-acetylcysteine was expressed by an increase of intracellular glutathione and of the level of metabolic reduction of the redox indicator Alamar Blue. The apoptogenic effect of acetaminophen was assessed by flow cytometry of annexin V binding, nuclear hypodiploidity, intracellular Ca2+, as well as by ultrastructural examination. Beyond 24 hr of acetaminophen exposure, necrosis was also noticed. We conclude that acetaminophen-induced oxidative damage in HepG2 cultured cells can be prevented by exposure to N-acetylcysteine. However, apoptosis, either early or late, here demonstrated, is not avoided by exposure to N-acetylcysteine. N-Acetylcysteine did not prevent acetaminophen-induced plasma membrane asymmetry, nuclear damage, alterations of Ca2+ homeostasis and ultrastructural changes.
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PMID:N-acetylcysteine does not protect HepG2 cells against acetaminophen-induced apoptosis. 1512 91

Treatment of mouse macrophages with picolinic acid (PA) and gamma-interferon (IFNgamma) led to the restriction of Mycobacterium avium proliferation concomitant with the sequential acquisition of metabolic changes typical of apoptosis, mitochondrial depolarization, annexin V staining and caspase activation, over a period of up to 5 days. However, triggering of cell death by ATP, staurosporine or H(2)O(2) failed to affect mycobacterial viability. In contrast to untreated macrophages where extensive interactions between phagosomes and endosomes were observed, phagosomes from treated macrophages lost the ability to acquire endosomal dextran. N-Acetylcysteine was able to revert both the anti-mycobacterial activity of treated macrophages as well as the block in phagosome-endosome interactions. The treatment, however, induced only a minor increase in the acquisition of lysosomal markers, namely Lamp-1, and did not increase to any great extent the acidification of the phagosomes. These data thus suggest that the anti-mycobacterial activity of PA and IFNgamma depends on the interruption of intracellular vesicular trafficking, namely the blocking of acquisition of endosomal material by the microbe.
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PMID:Induction of Mycobacterium avium growth restriction and inhibition of phagosome-endosome interactions during macrophage activation and apoptosis induction by picolinic acid plus IFNgamma. 1513 12

B-cell chronic lymphocytic leukemia (CLL) is characterized by accumulation of clonal lymphocytes resistant to apoptosis. We evaluated the ability of the investigational antileukemic agent adaphostin to induce apoptosis in CLL B cells and synergize with fludarabine in vitro. Analysis by annexin V/propidium iodide (PI) staining revealed that the concentration of adaphostin required to induce 50% cell death (IC50) at 24 hours was 4.2 microM (range, 1.10-11.25 microM; median, 4.25 microM; n=29) for CLL isolates and more than 10 microM for B and T cells from healthy donors. Immunoblots demonstrated adaphostin induced poly(adenosine diphosphate-ribose) polymerase (PARP) cleavage and cleavage of caspase-3 substrates, suggesting that adaphostin induces apoptosis. Adaphostin increased the level of reactive oxygen species (ROS) within CLL B cells, and the antioxidant N-acetylcysteine blocked both adaphostin-induced ROS generation and apoptosis. Adaphostin also caused a decrease in the level of the antiapoptotic protein Bcl-2. When adaphostin was combined with fludarabine (F-ARA-AMP), a synergistic effect on cell death was observed in all 10 CLL samples. These findings not only indicate that adaphostin induces apoptosis selectively in CLL B cells through a mechanism that involves ROS generation but also demonstrate its ability to augment the effects of fludarabine. Further preclinical development of adaphostin as a novel agent for the treatment of CLL appears warranted.
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PMID:Adaphostin-induced apoptosis in CLL B cells is associated with induction of oxidative stress and exhibits synergy with fludarabine. 1538 86

The aim of this study was to elucidate death pathways in macrophages resulting from exposure to triacylglycerols (TG), mechanisms which may be relevant to the development of atherosclerosis. A commercial TG emulsion (lipid emulsion, LE; 0.1-1.5 mg lipids/ml) was added to J774.2 cells in culture. Within the first 24 h after TG treatment, cellular reactive oxygen species (ROS) levels were strongly elevated and basal caspase-3 activity was attenuated. In contrast, after 48 h, ROS production was arrested. TG-mediated ROS production was demonstrated to be via mitochondrial complex 1 of the electron-transfer chain since the inhibitor of complex 1 rotenone significantly attenuated the cellular ROS levels in TG-treated cells. The TG effect culminated in cell death, with no caspase-3 activation. We therefore evaluated the effect of TG on apoptotic cells showing high caspase activity. TG induced elevated ROS levels and suppressed caspase-3 in apoptotic cells pretreated for 24 h with cycloheximide. Dual staining with propidium iodide and Annexin V followed by flow cytometric analysis showed that TG facilitated cell death with clear necrotic characteristics. To elucidate whether the necrotic cell death process is indeed oxidant dependent, antioxidant protection was studied. Treatment with N-acetylcysteine (NAC) (0.5 mM), ascorbic acid (0.5 mM), and resveratrol (0.2 mM) protected against the TG lipotoxic effect, while, surprisingly, lipophilic antioxidants did not. The combination of NAC, ascorbic acid, and resveratrol, each at much lower concentrations, had a synergistic protective effect. In conclusion, we show here for the first time that exposure to TG can directly regulate lipotoxicity in macrophages by inducing mitochondria-mediated prolonged oxidative stress; this, in turn, can inactivate the apoptotic caspase system, resulting in necrotic cell death which can be prevented by specific antioxidants.
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PMID:Mechanism underlying oxidative stress-mediated lipotoxicity: exposure of J774.2 macrophages to triacylglycerols facilitates mitochondrial reactive oxygen species production and cellular necrosis. 1580 20

Curcumin is the main biologically active phytochemical compound in turmeric. It has been shown to have anticarcinogenic activity. The aims of the study were to identify the mechanism of apoptosis of HL-60 human promyelocytic leukemic cells induced by curcumin and to determine the effects of water-soluble antioxidants, ascorbic acid, Trolox (a water-soluble form of vitamin E), glutathione (GSH) and N-acetylcysteine (NAC) on this process. HL-60 cells were incubated with curcumin for 24 h and apoptotic cells were quantitated by flow cytometry following staining with annexin V-FITC and propidium iodide. Curcumin-treated HL-60 cells produced reactive oxygen species as detected by the dichlorofluorescein fluorescent assay. Apoptosis occurred via the mitochondria pathway as curcumin reduced mitochondrial membrane potential in a dose-dependent manner. In the presence of 10 microM curcumin, vitamin C (56 nM-5.6 microM) inhibited apoptosis of HL-60 cells; GSH at low concentration (1 microM) reduced apoptosis but had no effect at higher concentrations (10, 100 microM); and Trolox and NAC at 10 and 100 microM, respectively, enhanced apoptosis, but this effect was abolished at higher concentration (1 mM) of NAC. MAPKK/MEK inhibitor PD98059, enhanced curcumin-induced HL-60 apoptotic cell death.
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PMID:Effects of water-soluble antioxidants and MAPKK/MEK inhibitor on curcumin-induced apoptosis in HL-60 human leukemic cells. 1623 87

Cadmium being a potent immunotoxicant, affects both humoral and cell mediated immunity. However, its effect on spleen is not clearly understood. Hence, to delineate the action of Cd, mouse splenic lymphocytes were exposed to Cd (10, 25 and 50 microM) for 60 min, 1.5, 3, 6 and 18 h. At 6 h, apoptosis was reflected by DNA fragmentation, increased sub-G1 population (apoptotic DNA) and apoptotic cells (Annexin V binding assay). The early stage markers of apoptosis, i.e. decreased mitochondrial membrane potential and caspase-3 activation were observed as early as 1.5 h by the highest dose of Cd (50 microM). Significant ROS production by 25 and 50 microM Cd at 60 min occurred prior to the lowering of mitochondrial membrane potential, suggesting involvement of ROS in causing mitochondrial membrane damage. N-acetylcysteine and pyrrolidine dithiocarbamate (thiol antioxidants) lowered the sub-G(1) population, inhibited the ROS generation and raised the GSH levels induced by Cd. Buthionine sulfoximine (GSH depletor) on the other hand, enhanced the ROS production as well as the sub-G1 fraction. These results imply that ROS is a critical mediator of Cd-induced apoptosis and that cadmium may compromise splenic immune function by accelerating apoptosis.
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PMID:Oxidative stress and apoptotic changes in murine splenocytes exposed to cadmium. 1641 50

Particulate air pollution is associated with respiratory morbidity and has cytotoxic and pro-inflammatory effects. The effects of diesel exhaust particles (DEP) on proliferation and apoptosis of A549 lung epithelial cells were examined. When deprived of serum (serum starvation), epithelial cell numbers fell, but DEP (5-200 microg.mL-1) prevented this. Using flow cytometric analysis of propidium iodide (PI) staining, DEP (10 microg.mL-1) increased cells in the S phase of cell cycle from 12.85 to 18.75% after 48 h, reversing serum starvation-induced G0/1 arrest. DEP also reduced the increase in apoptotic cells, as defined by double expression of annexin V/PI, observed after serum starvation (from 28.35 to 15.46%). The antioxidants, N-acetylcysteine (NAC; 33 mM) and AEOL10113 (10-100 microM), the N-terminal c-jun kinase inhibitor, SP600125 (33 microM), and nuclear factor-kappaB inhibitor, SN50 (33 microM), inhibited DEP-induced cell number increase. NAC inhibited DEP-induced reduction of G0/1 and increase in cells in the S and G2/M phases. Expression of p21CIP1/WAF1 mRNA and protein seen with serum starvation was reduced by DEP. In conclusion, diesel exhaust particles prevented serum starvation-led decreases in A549 epithelial cells by inducing cell cycle progression and preventing apoptosis, processes involving oxidative stress, inhibition of p21CIP1/WAF1 expression and stimulation of N-terminal c-jun kinase and nuclear factor-kappaB. Therefore, low-dose diesel exhaust particle exposure may lead to lung epithelial cell hyperplasia.
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PMID:Regulation of human lung epithelial cell numbers by diesel exhaust particles. 1658 72

The mechanisms underlying the cytotoxic action of pure fullerene suspension (nano-C60) and water-soluble polyhydroxylated fullerene [C60(OH)n] were investigated. Crystal violet assay for cell viability demonstrated that nano-C60 was at least three orders of magnitude more toxic than C60(OH)n to mouse L929 fibrosarcoma, rat C6 glioma, and U251 human glioma cell lines. Flow cytometry analysis of cells stained with propidium iodide (PI), PI/annexin V-fluorescein isothiocyanate, or the redox-sensitive dye dihydrorhodamine revealed that nano-C60 caused rapid (observable after few hours), reactive oxygen species (ROS)-associated necrosis characterized by cell membrane damage without DNA fragmentation. In contrast, C60(OH)n caused delayed, ROS-independent cell death with characteristics of apoptosis, including DNA fragmentation and loss of cell membrane asymmetry in the absence of increased permeability. Accordingly, the antioxidant N-acetylcysteine protected the cell lines from nano-C60 toxicity, but not C60(OH)n toxicity, while the pan-caspase inhibitor z-VAD-fmk blocked C60(OH)n-induced apoptosis, but not nano-C60-mediated necrosis. Finally, C60(OH)n antagonized, while nano-C60 synergized with, the cytotoxic action of oxidative stress-inducing agents hydrogen peroxide and peroxynitrite donor 3-morpholinosydnonimine. Therefore, unlike polyhydroxylated C60 that exerts mainly antioxidant/cytoprotective and only mild ROS-independent pro-apoptotic activity, pure crystalline C60 seems to be endowed with strong pro-oxidant capacity responsible for the rapid necrotic cell death.
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PMID:Distinct cytotoxic mechanisms of pristine versus hydroxylated fullerene. 1647 88

Cytochrome P450 2E1 (CYP2E1) potentiates oxidative stress-mediated cell death. Heat shock proteins (Hsps) modulate the stability and function of numerous proteins. We examined the effect of geldanamycin (GA), an inhibitor of Hsp90, on CYP2E1-mediated toxicity in transfected HepG2 cells overexpressing CYP2E1 (E47 cells). Basal expression of CYP2E1 and Hsp90 was higher in E47 cells compared with control C34 cells, which do not express CYP2E1. Treatment with GA resulted in significant toxicity to E47 cells compared with C34 cells. An enhanced loss of E47 cell viability was also observed using two different inhibitors of Hsp90, herbimycin A and radicicol. Treatment of E47 cells with GA caused depletion of glutathione coupled to an increase in reactive oxygen species level and lipid peroxidation. These effects of GA were more pronounced in the E47 than the C34 cells. The antioxidants trolox and N-acetylcysteine prevented the increased reactive oxygen species accumulation and resultant loss of viability. GA caused increased caspase 3 activity and Annexin V staining in E47 cells, suggesting an apoptotic mode of cell death. A decrease in mitochondrial membrane potential was observed in GA-treated HepG2 cells, and mitochondrial permeability transition inhibitors prevented the cytotoxicity of GA. These results suggest that Hsp90 is protective against CYP2E1-dependent oxidant stress and loss of cell viability in HepG2 cells.
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PMID:Geldanamycin, an inhibitor of Hsp90, potentiates cytochrome P4502E1-mediated toxicity in HepG2 cells. 1651 47


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