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)

Annexin II binds in a calcium-dependent manner to acidic phospholipids and is a substrate of some protein kinases. An N-terminally shortened form of human annexin II was crystallized and its molecular structure determined. It is very similar to two previously described members of this protein family, annexin I and annexin V. The protein structure is nearly completely alpha-helical organized as four compact domains which consist of five alpha-helices each. The domains surround a hydrophilic pore. The calcium binding sites are located at the convex side of the structure as in annexin V. Recombinant and natural porcine annexin II are active as ion channel with characteristics similar to annexin V, while N-terminally shortened annexin II and the heterotetramer (annexin II-p11)2 are inactive. Two cysteine residues, Cys133 and Cys262, form a disulphide bridge connecting domains II and III, adding further weight to the notion that ion channel activity does not require major structural rearrangements.
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PMID:The crystal structure and ion channel activity of human annexin II, a peripheral membrane protein. 863 85

1. House dust mite (HDM) allergens with cysteine and serine proteinase activity are risk factors for allergic sensitization and asthma. A simple method to fractionate proteinase activity from HDM faecal pellets into cysteine and serine class activity is described. 2. Both proteinase fractions increased the permeability of epithelial cell monolayers. The effects of the serine proteinase fraction were inhibited by 4-(2-aminoethyl)-benzenesulphonyl fluoride hydrochloride (AEBSF) and soybean trypsin inhibitor (SBTI). The effects of the cysteine proteinase fraction could be inhibited by E-64. No reciprocity of action was found. 3. Treatment of epithelial monolayers with either proteinase fraction caused breakdown of tight junctions (TJs). AEBSF inhibited TJ breakdown caused by the serine proteinase fraction, whereas E-64 inhibited the cysteine proteinase fraction. 4. Agarose gel electrophoresis revealed that the proteinases induced DNA cleavage which was inhibited by the matrix metalloproteinase inhibitor BB-250. Compound E-64 inhibited DNA fragmentation caused by the cysteine proteinase fraction, but was without effect on the serine proteinase fraction. Staining of proteinase-treated cells with annexin V (AV) and propidium iodide (PI) revealed a diversity of cellular responses. Some cells stained only with AV indicating early apoptosis, whilst others were dead and stained with both AV and PI. 5. HDM proteinases exert profound effects on epithelial cells which will promote allergic sensitization; namely disruption of intercellular adhesion, increased paracellular permeability and initiation of cell death. Attenuation of these actions by proteinase inhibitors leads to the conclusion that compounds designed to be selective for the HDM enzymes may represent a novel therapy for asthma.
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PMID:Class specific inhibition of house dust mite proteinases which cleave cell adhesion, induce cell death and which increase the permeability of lung epithelium. 972 Jul 72

If life is to continue, cells that have completed their useful function(s) must die in a timely manner. Apoptosis, programmed cell death, is a natural, orderly, energy-dependent process that causes cells to die without inducing an inflammatory response. In the heart, apoptosis plays pivotal roles in the development of myocarditis, cardiomyopathies, transplant rejection, the periinfarct zone in myocardial infarction, and reperfusion injury. Apoptosis is triggered either by a decrease in factors required to maintain the cell in good health or by an increase in factors which cause damage to the cell. When these factors tilt in the direction of death and the cell has sufficient time to respond, a common proteolytic cascade involving cysteine aspartic acid-specific proteases (caspases) is activated to initiate apoptosis. Cells that die by apoptosis autodigest their DNA and nuclear proteins, change the phospholipid composition on the outer surface of their cell membrane, and form lipid enclosed vesicles, which contain noxious intracellular contents, organelles, autodigested cytoplasm, and DNA. The compositional cell membrane phospholipid change that occurs with the onset of apoptosis is marked by the sudden expression of phosphatidylserine (PS), a phospholipid that ordinarily appears on the inner leaflet of the membrane, on the external leaflet of the membrane. The constant exposure of PS during apoptosis makes it an attractive target for radiopharmaceutical imaging. An endogenous human protein, annexin V, has a high affinity (kd = 7 nmol/L) for PS bound to the cell membrane. Fluorescence-labeled annexin V is used for histologic and cell-sorting studies to identify apoptotic cells. Annexin has been radiolabeled and binds to cells undergoing apoptosis in vivo. This review outlines some of the key features of apoptosis as contrasted to necrosis (unregulated cell death) and describes how these processes can be imaged with radionuclide techniques.
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PMID:In vivo detection of apoptotic cell death: a necessary measurement for evaluating therapy for myocarditis, ischemia, and heart failure. 1054 49

We previously reported the induction of apoptotic DNA fragmentation by nonsteroidal anti-inflammatory drugs (NSAIDs) in cultured rat gastric cells, and indicated that prostaglandin-synthesis is only marginally involved in the apoptotic process. In the present study, we examined whether the generation of reactive oxygen species is critically involved in NSAID-induced apoptosis. Indomethacin, sodium diclofenac, flurbiprofen, zaltoprofen, etodolac, but not mofezolac, enhanced apoptotic DNA fragmentation and mRNA expression for cyclooxygenase-2 in AGS cells, a cell line derived from human gastric epithelium. The apoptotic effect of indomethacin was then confirmed by fluorescent staining of the cells with annexin V. Apoptotic DNA fragmentation induced by indomethacin and flurbiprofen was suppressed by incubation of the cells with the anti-oxidants pyrrolidine dithiocarbamate, diphenyleneiodonium chloride, and N-acetyl-L-cysteine. These two NSAIDs also enhanced release from the cells of 8-isoprostane, a nonenzymatic product by free-radical-mediated peroxidation of arachidonic acid. Further, lucigenin chemiluminescence showed that the intracellular production of reactive oxygen species increased in cells treated with indomethacin. The present data thus indicate a crucial association between the generation of reactive oxygen species and NSAID-induced apoptosis in gastric epithelial cells.
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PMID:Reactive oxygen species are involved in the apoptosis induced by nonsteroidal anti-inflammatory drugs in cultured gastric cells. 1059 27

Damage to bone tissue due to heat shock is one of the main causes of the failure of osseointegration at the bone-implant interface. To investigate the effect of heat shock on regeneration of bone tissue, osteoblasts were exposed to heat shock for 10 minutes at 42, 45, or 48 degrees C or kept at 37 degrees C as a control. After 10 minutes of heat shock, disruption of actin filaments was seen in the cells and the degree of disruption increased with the temperature. The cytoskeleton reassembled after a 12-hour incubation at 37 degrees C in the cells treated at 42 or 45 degrees C, but this reversible recovery did not occur in the cells treated at 48 degrees C. Flow cytometric analysis showed that heat shock at 48 degrees C increased the number of necrotic cells to 15-20% within minutes (p < 0.05 compared with 37 degrees C). Apoptosis, evidenced by annexin V staining, DNA laddering, and caspase 3 activation, started after 6-8 hours of incubation, reached a peak at 12 hours, and gradually declined (p<0.05). Pretreatment with the antioxidant N-acetyl-L-cysteine reduced the necrosis induced at 48 degrees C of heat shock by one-half (p<0.05) but had no significant effect on caspase 3 activation induced by heat shock, suggesting that reactive oxygen species were critical in heat shock-induced necrosis but not in apoptosis. Heat shock at 48 degrees C induced a sustained translocation of p53 into the nucleus and a sustained activation of c-jun N-terminal kinase, whereas that at 42 and 45 degrees C induced only transient p53 translocation and c-jun N-terminal kinase activation. These results suggest that the sustained activation of p53 and c-jun N-terminal kinase pathways may contribute to heat shock-induced apoptosis. On the other hand, heat shock protein 70 increased dramatically in the cells treated at 45 or 48 degrees C, suggesting that the protecting mechanism in the cells was also activated. Such protection was able to prevent apoptosis in cells treated at 45 degrees C but not in those treated at 48 degrees C.
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PMID:Heat shock-induced necrosis and apoptosis in osteoblasts. 1063 56

Smoking has been associated with a large number of diseases, in particular cancers. Among the many substances identified in tobacco smoke, reactive oxygen species (ROS) are major carcinogens. We have previously reported that exposure of mammalian cells to tobacco smoke induces the expression of stress proteins, as well as apoptosis (programmed cell death). Here we examined the effects of tobacco smoke on mitochondrial membrane potential (deltapsim), since mitochondria have been proposed to control the effector phase of apoptosis. We used normal human monocytes for these experiments, with the prospect for application of deltapsim as a biomarker of oxidative stress. Tobacco smoke induced mitochondrial depolarization at 3 h, and apoptosis (or necrosis for higher concentrations) after 16 h. Apoptosis was assessed by both a functional approach (annexin V binding) and morphological analysis (electron microscopy). N-acetyl-cysteine prevented tobacco smoke-induced deltapsim disruption and apoptosis, while the caspase inhibitor Z-VAD.Fmk did not affect deltapsim, though preventing apoptosis, and superoxide dismutase had no effect. Our data designate mitochondria as a target for ROS-mediated effects of tobacco smoke exposure.
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PMID:Tobacco smoke induces mitochondrial depolarization along with cell death: effects of antioxidants. 1073 Oct 97

We and others previously demonstrated that human multiple myeloma (MM) cells express CD40 and have an active CD40-growth regulatory pathway. This study characterizes the growth outcome of soluble (gp39) or membrane-bound recombinant human CD40-ligand (rCD40L) and its relationship with Fas-dependent apoptosis. Contrary to the moderate growth-stimulatory effect of the CD40-MAb G28.5, gp39 inhibited 3H-thymidine uptake of the plasma dyscrasia lines ARH-77, U266, and HS-Sultan in a dose-dependent fashion by up to 82%. By comparison, RPMI 8226 cells were resistant to CD40L-growth modulation, which may be attributable to a single base substitution (TCA-->TTA, serine-->leucine) at the 3rd cysteine-rich extramembrane region of CD40. Gp39 similarly reduced myeloma clonogenic colony (MCC) formation in patient primary bone marrow cultures by 50% (40-76%; n=6). Studies using transfectant L cells that constitutively expressed CD40L showed that membrane-bound CD40L inhibited the growth of ARH-77, U266, and HS-Sultan cells (66%, 63%, and 32%, respectively), whereas untransfected L cells did not. Growth inhibition by gp39 or CD40L+ L cells was neutralized by coincubation with the CD40L antibodies 5c8 or LL48. CD40L-treatment increased apoptotic activity of MM cells, as defined by oligonucleosomal DNA fragmentation and an increased binding to annexin V (16-28%). All three untreated CD40-responsive MM lines expressed the Fas/Apo-1/CD95 antigen (65-92% CD95+). However, only ARH-77 cells responded to the growth inhibitory effect of the CD95-agonistic antibody CH-11. CD95 expression was not affected significantly by gp39 treatment, and growth inhibition by CH-11 was additive to gp39 (from 42% to 64% decrease in 3H-thmidine uptake). Conversely, the CD95 antagonist antibody ZB4 reversed the Fas-dependent growth inhibitory process but did not significantly alter gp39-mediated growth outcome. Gp39 treatment lowered the expression of TNFR-associated factors TRAF4 and TRAF6 by 38% and 32%, respectively, whereas detectable levels of TRAF1,2,3, and 5 levels remained unchanged. Our observations indicate that the CD40L-binding inhibits human MM cell growth and increases its apoptotic activity. This growth inhibitory effect corresponds to lower levels of cytoplasmic TRAF signaling elements, and appears independent of the Fas-signaling pathway. CD40 receptor mutation may lead to unresponsiveness to CD40 growth modulation in multiple myeloma cells.
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PMID:CD40 ligand-induced apoptosis is Fas-independent in human multiple myeloma cells. 1078

Exposure to environmental contaminants, such as polychlorinated biphenyls (PCBs), may severely compromise normal function of vascular endothelial cells (EC). We have previously shown that PCB 77 (3,3',4,4'-tetrachlorobiphenyl), an arylhydrocarbon receptor (AhR) agonist, can induce oxidative stress in cultured EC. We now show that PCB 77 can activate EC and induce a cellular stress response that is reflected by the activation of c-Jun N-terminal/stress-activated protein kinases (JNK/SAPK). Our data also suggest that this PCB 77-mediated stress response can be modulated by the intracellular glutathione content. EC treated with buthionine-sulphoximine (BSO), an inhibitor of glutathione synthesis, further enhanced PCB-induced JNK/SAPK activity. This stress response was sustained only in the presence of BSO plus PCB 77. Media supplementation with the glutathione precursor N-acetyl-cysteine (NAC) reduced PCB 77-induced JNK/SAPK. Intracellular glutathione also may be implicated in PCB-induced EC apoptosis. Individual treatment with PCB, BSO, or linoleic acid induced activation of caspase 3. Compared to PCB 77 alone, annexin V activity was further amplified during combined treatment with BSO and PCB 77. DNA fragmentation was mostly observed when cells were treated with both BSO and PCB 77. The caspase 3-specific inhibitor DEVD-CHO protected cells against PCB 77/BSO-mediated apoptosis and inhibited the caspase activity without affecting JNK/SAPK activation or cellular glutathione levels. These results suggest that AhR ligands, such as PCB 77, cause vascular EC dysfunction by modulating intracellular glutathione, which subsequently leads to activation of stress-specific kinases. Furthermore, inhibition of glutathione synthesis by BSO can further potentiate the PCB 77-induced stress response and ultimately lead to apoptotic cell death.
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PMID:Cellular glutathione status modulates polychlorinated biphenyl-induced stress response and apoptosis in vascular endothelial cells. 1087 16

Oxidative stress induced by light activation of photosensitizers is regarded to have a role in triggering cell death pathways during photodynamic therapy (PDT). Reactive oxygen species have been proposed to act as signal transduction molecules activating downstream reactions that lead to apoptosis. Mainly debated is the cooperating role of other signaling systems like calcium or pH. The present work contributes to this discussion by studying PDT effects in cell cultures of rat bladder epithelial cells for the hydrophilic tetrasulfonated aluminum phthalocyanine (AlPcS4). Cells were coincubated with the photosensitizer and the calcium-sensitive probe Fluo-3. The light-induced reactions were analyzed with a confocal laser scanning microscope. The dynamics of the process during light activation was observed with subcellular resolution. A transient calcium elevation during the irradiation process was detected, especially in the cell's nuclei, followed by a more sustained increase. The evaluation of the energy-dose-dependent phototoxicity after an incubation time with the photosensitizer of 1 and 24 h, showed enhanced phototoxicity when the drug was present for 24 h. Surprisingly, stimulation of cell proliferation was observed at very low light doses (at 0.2 J/cm2) when the drug was incubated for 24 h (cell viability 160%). Induction of apoptosis could be observed after irradiation with fluences between 1 and 3 J/cm2. Apoptotic cells were identified with fluorescein isothiocyanate-labeled Annexin V, which binds to phosphatidylserine after its translocation to the outer plasma membrane. In the presence of the antioxidant pyrrolidinedithiocarbamate the transient calcium elevation was totally inhibited, as was the subsequent translocation of PS. In contrast, N-acetyl-L-cysteine did not suppress the transient calcium increase. Our data might be consistent with calcium regulated processes during AlPcS4-PDT and the involvement of oxygen radicals.
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PMID:Light-induced apoptosis involves a defined sequence of cytoplasmic and nuclear calcium release in AlPcS4-photosensitized rat bladder RR 1022 epithelial cells. 1094 75

[(99m)Tc]Annexin V can be used to image organs undergoing cell death during cancer chemotherapy and organ transplant rejection. To simplify the preparation and labeling of annexin V for nuclear-medicine studies, we have investigated the addition of peptide sequences that will directly form endogenous chelation sites for (99m)Tc. Three mutant molecules of annexin V, called annexin V-116, -117, and -118, were constructed with N-terminal extensions of seven amino acids containing either one or two cysteine residues. These molecules were expressed cytoplasmically in Escherichia coli and purified to homogeneity with a final yield of 10 mg of protein/L of culture. Analysis in a competitive binding assay showed that all three proteins retained full binding affinity for erythrocyte membranes with exposed phosphatidylserine. Using SnCl(2) as reducing agent and glucoheptonate as exchange agent, all three proteins could be labeled with (99m)Tc to specific activities of at least 50-100 microCi/microg. The proteins retained membrane binding activity after the radiolabeling procedure, and quantitative analysis indicated a dissociation constant (K(d)) of 7 nmol/L for the annexin V-117 mutant. The labeling reaction was rapid, reaching a maximum after 40 min at room temperature. The radiolabeled proteins were stable when incubated with phosphate-buffered saline or serum in vitro. Proteins labeled to a specific activity of 25-100 microCi/microg were injected intravenously in mice at a dose of 100 microg/kg, and biodistribution of radioactivity was determined at 60 min after injection. Uptake of radioactivity was highest in kidney and liver, consistent with previous results obtained with wild-type annexin V. Cyclophosphamide-induced apoptosis in vivo could be imaged with [(99m)Tc]annexin V-117. In conclusion, annexin V can be modified near its N-terminus to incorporate sequences that form specific chelation sites for (99m)Tc without altering its high affinity for cell membranes. These annexin V derivatives may be useful for in vivo imaging of cell death.
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PMID:Development and characterization of annexin V mutants with endogenous chelation sites for (99m)Tc. 1108 42


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