Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P42574 (caspase-3)
 45,978 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We explored the role of CD18 (beta2 integrin) in platelet physiology, using mice genetically deficient in CD18 (CD18 -/-), or its main ligand CD54 (ICAM-1, CD54 -/-). CD18 and CD11a were evident in platelets from +/+, but not from CD18 -/- mice, as seen by immunofluorescence or Western blots. CD18 mRNA was also detectable by RT-PCR in platelets from +/+, but not from CD18 -/- mice. The life span of platelets was significantly shorter in CD18 -/- than in +/+ or CD54 -/- mice, as seen by in vivo biotinylation. When a local inflammation was elicited by the intra-tracheal injection of TNF, labeled platelets from +/+, but not from CD18 -/- donors, did localize in the lung. The content of Bcl-3 was about 20-fold higher in platelet from CD18 -/-, than in those from +/+ or CD54 -/- donors, as seen on Western blots or by immunofluorescence and flow cytometry, while the amount of pro-caspase-3 was decreased. An activation of caspases in platelets from CD18 -/- was also evidenced by protease assays. Accordingly, gelsolin, a protein cleaved by caspase-3, showed a low-molecular-weight band in platelets from CD18 -/- but not from +/+ donors. These results demonstrate that the beta2 integrin, present in mouse platelets, modulates caspase activation and consequently platelet life span and response to TNF.
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PMID:Beta2 integrin modulates platelet caspase activation and life span in mice. 1130 22

We have reported that human autoantibodies reacting with the polymorphonuclear neutrophil (PMN)-anchored FcgammaRIIIb (CD16) protect these cells from spontaneous apoptosis. In this study, we used anti-CD16 F(ab')(2) to delineate the mechanism(s) whereby the PMN life span is extended. As documented using four methods, CD16 cross-linking impeded spontaneous apoptosis, whereas anti-CD18 F(ab')(2) exerted no effect. Incubation of PMNs with anti-CD16 prevented the up-regulation of beta(2) integrins, particularly CD11b, which is the alpha-chain of complement receptor type 3, but also CD18, which is its beta-chain, as well as CD11a and CD11c. Anti-CD16-conditioned supernatant of PMNs diminished the percentage of annexin V-binding fresh PMNs after another 18 h in culture, whereas the negative control anti-CD18 had no effect. The expression of mRNA for G-CSF and GM-CSF was induced by anti-CD16, followed by the release of G-CSF and GM-CSF in a dose-dependent manner. Anti-G-CSF and anti-GM-CSF mAbs abrogated the antiapoptotic effect of the related growth factors. The delay in apoptosis was accompanied by a down-regulated expression of Bax, and a partial reduction of caspase-3 activity. These data suggest an autocrine involvement of anti-CD16-induced survival factors in the rescue of PMNs from spontaneous apoptosis. Thus, apoptosis of aged PMNs can be modulated by signaling through FcgammaRIIIb, which may occur in patients with PMN-binding anti-FcgammaRIIIb autoantibodies.
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PMID:Cross-linking of human FcgammaRIIIb induces the production of granulocyte colony-stimulating factor and granulocyte-macrophage colony-stimulating factor by polymorphonuclear neutrophils. 1156 19

Hemodialysis patients exhibit a defective immune response leading to an increased susceptibility of infections and neoplasms. Far from being helpful, dialytic therapy per se also may be responsible for this acquired immunodeficiency. Dialysis membranes and bacterial products present in dialysis water may trigger and even perpetuate an abnormal mononuclear cell activation. Upon contact with cellulosic dialysis membranes, monocytes display an increased expression of surface markers of cell activation, such as adhesion molecules CD18, CD49, CD54 and the lipopolysaccharide (LPS) ligand (CD14). Moreover, proinflammatory cytokines as IL-1beta and TNF-alpha are released both in vivo and in vitro when monocytes are exposed to cellulosic membranes. Of special interest is the fact that end-stage renal disease patients undergoing hemodialysis exhibit an increased mononuclear cell apoptosis. This apoptosis is directly related to the degree of biocompatibility of the dialysis membrane. Apoptosis is activated when monocytes enter in contact with the cellulosic dialysis membrane through cell surface receptors linked to G-proteins. In early steps of apoptosis signaling, pertussis toxin-sensitive G proteins are coupled to protein kinase C (PKC)-dependent phosphorylative mechanisms. Furthermore, recent evidence support that the execution phase of apoptosis is mediated by a caspase-3 dependent pathway. Finally, very recent available data support that monocytes subjected to repeated activation suffer a process of accelerated senescence, as demonstrated by the senescent phenotype (CD14 and CD32) expressed and their shortened telomeric length. This senescent profile may generage a defective cellular response in acute stress situations, explaining (at least in part) the altered immune response observed in hemodialysis patients.
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PMID:Cell apoptosis and hemodialysis-induced inflammation. 1198 20

Mannheimia (Pasteurella) haemolytica A1 produces several virulence factors that play an important role in the pathogenesis of bovine pneumonic pasteurellosis. Foremost among these is a leukotoxin (LKT) that specifically kills ruminant leukocytes. Recent evidence suggests that M. haemolytica LKT binding to bovine leukocytes is mediated by the beta(2)-integrin CD11a/CD18 (lymphocyte function-associated antigen 1 [LFA-1]), which subsequently induces activation and cytolysis of these cells. Inflammatory cytokines, which are released during viral and bacterial infection, are reported to increase LFA-1 expression and conformational activation. We investigated the effects of the inflammatory cytokines interleukin-1beta (IL-1beta), tumor necrosis factor alpha (TNF-alpha), and gamma interferon (IFN-gamma) on the interaction of M. haemolytica LKT with bovine peripheral blood neutrophils (PMNs). In this study we demonstrated, by flow cytometry, that bovine PMNs increased their binding to an anti-bovine LFA-1 monoclonal antibody (BAT75A) following in vitro incubation with IL-1beta, TNF-alpha, or IFN-gamma. Incubation with cytokines also increased CD18 expression, as assessed by real-time PCR and by Western blotting. Increased LFA-1 expression by PMNs exposed to cytokines was associated with increased LKT binding and cytotoxicity. The latter represented, at least in part, enhanced PMN apoptosis, as assessed by propidium iodine staining and caspase-3 activation. The results of this study suggest that inflammatory cytokines may play an important role in enhancing the biological response of bovine PMNs to M. haemolytica LKT.
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PMID:Inflammatory cytokines enhance the interaction of Mannheimia haemolytica leukotoxin with bovine peripheral blood neutrophils in vitro. 1211 43

Anti-platelet antibodies are known to contribute to some types of thrombocytopenia. In this work we investigated anti-platelet antibodies with opposite influence upon activation and kinetics of platelet caspases. A rabbit anti-platelet antibody induced a profound thrombocytopenia, which was associated with an increase of microparticles in plasma and an activation of platelet caspases, as detected by the binding of a carboxyfluorescein-labeled fluoromethyl ketone probe (FAM-VAD-fmk). Furthermore, microparticles and thrombocytopenia were prevented by the injection of a caspase inhibitor ZVAD-fmk. In contrast, an anti-CD18 mAb (M18.2) induced a thrombocytosis, due to an increased platelet life-span and which was evident in wild-type (+/+), but not in CD18-/- or CD87-/-, mice indicating a requirement of these two surface molecules. Activation of caspases was decreased in platelets from mice injected with the M 18.2 mAb, as evidenced by a decreased binding of the VAD probe, detected by flow cytometry, or an increase in the level of pro-caspase-3, seen on Western blots. These observations indicate firstly, that anti-platelet antibodies can either promote or inhibit activation of platelet caspases, and secondly, that the activation of caspases regulates platelet life-span.
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PMID:Modulation of platelet caspases and life-span by anti-platelet antibodies in mice. 1214 31

IFN-gamma is critical for the protection against intracellular bacteria through activation of the antimicrobial machinery of phagocytes. Coxiella burnetii, the etiological agent of Q fever, is a strictly intracellular bacterium that inhabits monocytes/macrophages. We previously showed that IFN-gamma induced C. burnetii killing by promoting the apoptosis of infected monocytes. We show in this study that IFN-gamma-induced apoptosis of infected monocytes was characterized by a time- and dose-dependent activation of caspase-3. IFN-gamma-mediated caspase-3 activation and C. burnetii killing depend on the expression of membrane TNF. Indeed, TNF was transiently expressed on the cell surface of infected monocytes a few hours after IFN-gamma treatment. In addition, anti-TNF Abs inhibited IFN-gamma-mediated caspase-3 activation whereas soluble TNF had no effect on infected cells. Concomitantly, IFN-gamma induced homotypic adherence of C. burnetii-infected monocytes. The latter required the interaction of beta(2) integrins with CD54. When adherence was disrupted by pipetting, by a combination of Abs specific for CD11b, CD18, and CD54, or by an antisense oligonucleotide targeting CD18 mRNA, both cell apoptosis and bacterial killing induced by IFN-gamma were inhibited. Thus, adherence via CD54/beta(2) integrins together with membrane TNF are required to eliminate C. burnetii-infected cells through cell contact-dependent apoptosis. Our results reveal a new component of the antimicrobial arsenal mobilized by IFN-gamma against infection by intracellular bacteria.
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PMID:IFN-gamma-induced apoptosis and microbicidal activity in monocytes harboring the intracellular bacterium Coxiella burnetii require membrane TNF and homotypic cell adherence. 1244 37

Dysfunction and loss of human retinal pigment epithelial (HRPE) cells is a significant component of many ocular diseases, in which mononuclear phagocyte infiltration at the HRPE-related interface is also observed. In this study, we investigated whether HRPE cell apoptosis may be induced by overlay of IFN-gamma-activated monocytes. Human monocytes primed with IFN-gamma overlaid directly onto HRPE cells elicited significant increases in terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL)-positive HRPE cells (p < 0.0001) and decreases of proliferating cell nuclear antigen-positive (p < 0.0001) HRPE cells. The activated monocytes also induced HRPE cell caspase-3 activation, which was inhibited by the caspase-3 inhibitor, Z-DEVD-fmk. However, co-incubations in which activated monocytes were prevented from direct contact with HRPE cells or in which the monocytes were separated from the HRPE cells after 30 minutes of direct contact, did not induce significant HRPE cell apoptosis. Function-blocking anti-CD18 and anti-intercellular adhesion molecule-1 (ICAM-1) antibodies significantly reduced activated monocyte-induced TUNEL-positive HRPE cells by 48% (p = 0.0051) and 38% (p = 0.046), respectively. Anti-CD18 and anti-ICAM-1 antibodies significantly inhibited caspase-3 activity by 56% (p < 0.0001) and 45% (p < 0.0001), respectively. However, antibodies to vascular cell adhesion molecule-1, TNF-alpha, IL-1beta, or TNF-related apoptosis-inducing ligand did not inhibit apoptosis or caspase-3 activation. Direct overlay of monocytes also induced reactive oxygen metabolites (ROM) within HRPE cells. The intracellular HRPE cell ROM production was inhibited by the anti-CD18 and anti-ICAM-1 antibodies, but not by superoxide dismutase, presumably due to its failure to penetrate into HRPE cells. Accordingly, neither superoxide dismutase nor N(G)-monomethyl-L-arginine had significant effects on HRPE cell apoptosis or caspase-3 activation. Our results suggest that activated monocytes may induce ROM in HRPE cells through cell-to-cell contact, in part via CD18 and ICAM-1, and promote HRPE cell apoptosis. These mechanisms may compromise HRPE cell function and survival in a variety of retinal diseases.
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PMID:Activated monocytes induce human retinal pigment epithelial cell apoptosis through caspase-3 activation. 1292 Feb 41

We demonstrated previously that Actinobacillus actinomycetemcomitans leukotoxin (Ltx) is greatly able to induce apoptotic signaling in cells that are positive for lymphocyte function-associated antigen 1 (LFA-1), a cell receptor of Ltx. We investigated in this study whether inflammatory cytokines can regulate apoptosis of human leukemic HL-60 cells induced by Ltx. Of the cytokines tested, tumor necrosis factor alpha (TNF-alpha) significantly enhanced the Ltx-induced cell apoptosis. Northern and Western blotting analyses showed that TNF-alpha enhanced the expression of CD11a in the cells at both the mRNA and protein levels but did not do so for CD18 expression. TNF-alpha also enhanced the binding of Ltx to the cells. We also observed by measuring the mitochondrial transmembrane potential and the generation of superoxide anion that the cytokine enhanced Ltx-induced apoptosis in HL-60 cells. In addition, interleukin-1beta significantly enhanced Ltx-induced cell apoptosis, although the enhancing activity was lower than that of TNF-alpha. These stimulatory effects of both cytokines were also observed for human polymorphonuclear leukocytes. The ability of TNF-alpha to increase cell susceptibility to Ltx could be inhibited by preincubation of the cells with a monoclonal antibody against TNF receptor 1 but not by preincubation of the cells with a monoclonal antibody against anti-TNF receptor 2. Furthermore, the results of an assay of caspase 3 intracellular activity (PhiPhiLuxG1D2) showed that Ltx-induced caspase 3 activation was completely neutralized by CD18 antibody treatment, although significant neutralization was also observed with anti-CD11a antibody. Taken together, the results of the present study indicate that TNF-alpha acts as a potent stimulator of Ltx-induced HL-60 cell apoptosis via TNF receptor 1-mediated upregulation of LFA-1 expression.
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PMID:Tumor necrosis factor alpha enhances Actinobacillus actinomycetemcomitans leukotoxin-induced HL-60 cell apoptosis by stimulating lymphocyte function-associated antigen 1 expression. 1468 5

Leukocyte recruitment in the liver includes a two-step procedure in which selectin-dependent leukocyte rolling is a prerequisite for subsequent CD18-dependent leukocyte firm adhesion in postsinusoidal venules. However, the roles of the individual selectins in leukocyte rolling and adhesion, hepatocellular injury, and apoptosis remain elusive. Therefore, we examined the pathophysiological role of P-, E-, and L-selectin in male C57BL/6 mice challenged with lipopolysaccharide (LPS) and D-galactosamine (Gal) by use of intravital microscopy of the liver microcirculation. In control animals, administration of LPS-Gal provoked reproducible hepatic damage, including marked increases of leukocyte recruitment, liver enzymes, and hepatocyte apoptosis and reduced sinusoidal perfusion. Interestingly, pretreatment with an anti-P-selectin antibody (RB40.34) markedly reduced leukocyte rolling and firm adhesion by 65 and 71%, respectively. Moreover, interference with P-selectin function significantly improved sinusoidal perfusion and reduced the increase in liver enzymes by 49 to 84% in endotoxemic mice. Moreover, the activity of caspase-3 and the number of apoptotic hepatocytes were significantly reduced by 55 and 54%, respectively, in RB40.34-treated animals. In contrast, administration of an anti-E-selectin antibody (10E9.6) and an anti-L-selectin antibody (Mel-14) did not protect against endotoxin-induced leukocyte responses or hepatic injury. In conclusion, our novel findings document a principal role of P-selectin in mediating leukocyte rolling, a precondition to the subsequent firm adhesion of leukocytes in liver injury. Furthermore, our novel data demonstrate that inhibition of P-selectin function reduces hepatocellular injury and apoptosis, suggesting a causal relationship between leukocyte recruitment on one hand and hepatocellular injury and apoptosis on the other hand. Based on these findings, it is suggested that P-selectin may be an important therapeutic target in endotoxin-induced liver injury.
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PMID:Important role of P-selectin for leukocyte recruitment, hepatocellular injury, and apoptosis in endotoxemic mice. 1471 45

Stimulant-induced viability of neutrophils, nuclear-fragmentation, increase in intracellular calcium ([Ca2+]i), expression of annexin V on neutrophils and proteolysis of a fluorogenic peptide substrate Ac-DEVD-MCA (acetyl Asp-Glu-Val-Asp alpha-[4-methyl-coumaryl-7-amide]) by neutrophil lysates from five normal calves and three calves with leucocyte adhesion deficiency were determined to evaluate the apoptosis of normal and CD18-deficient neutrophils. Viability was markedly decreased in control neutrophils stimulated with opsonized zymosan (OPZ), compared to CD18-deficient neutrophils at 37 degrees C after incubation periods of 6 and 24 hours. The rate of apoptosis of control neutrophils stimulated with OPZ increased significantly depending on the incubation time, whereas no apparent increase in apoptosis was found in CD18-deficient neutrophils under the same conditions. Aggregated bovine (Agg) IgG-induced apoptosis of control neutrophils was not significantly different from that of CD18-deficient neutrophils. The expression of annexin V on OPZ-stimulated control neutrophils was greater than that of unstimulated ones 6 h after stimulation. No apparent increase in annexin V expression on CD18-deficient neutrophils was found with OPZ stimulation. A delay in apoptosis was demonstrated in CD18-deficient bovine neutrophils and this appeared to be closely associated with lowered signalling via [Ca2+]i, diminished annexin V expression on the cell surface, and decreased caspase 3 activity in lysates.
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PMID:Decreased apoptosis of beta 2- integrin-deficient bovine neutrophils. 1498 92


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