Cytochrome c Release, Mitochondrial Membrane Depolarization, Caspase-3 Activation, and Bax-α Cleavage During IFN-α-Induced Apoptosis in Daudi B Lymphoma Cells

2000 ◽  
Vol 20 (12) ◽  
pp. 1121-1129 ◽  
Author(s):  
Noriko Yanase ◽  
Kazutaka Ohshima ◽  
Hakuo Ikegami ◽  
Junichiro Mizuguchi
Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 2117-2117
Author(s):  
Swapan Kumar Dasgupta ◽  
Hanan Abdel-Monem ◽  
Anthony Prakasam ◽  
Perumal Thiagarajan

Abstract Abstract 2117 Poster Board II-94 The transbilayer movement of phosphatidylserine from the inner to the outer leaflet of membrane bilayer occurs during platelet activation and is essential for platelet procoagulant activity. Expression of phosphatidylserine also occurs in platelets stored more than 5 days in the blood bank. We have examined the role of mitochondrial pathways in activation-induced platelet procoagulant activity and during in vitro senescence. Collagen and thrombin-induced exposure of phosphatidylserine is associated with a decrease in mitochondrial membrane potential (MMP). Cyclosporin A, a known inhibitor of cyclophilin D, inhibited phosphatidylserine exposure and the loss of MMP. Consistent with this, platelets from CypD deficient mice had decreased loss of MMP and impaired phosphatidylserine exposure when treated with a combination of thrombin and collagen. However, there is no release of cytochrome c into the cytosol. Also there is no activation of caspase-3 or Rho associated kinase I (ROCK1). In sharp contrast to this, in platelets stored for more than 5 days, phosphatidylserine exposure is found to be associated with caspase-3 and ROCK1 activation. To delineate the mechanism we used ABT737, a BH3 mimetic that induces mitochondrial pathway of apoptosis via Bcl-2 family of proteins. ABT737-induced phosphatidylserine exposure was also associated with cytochrome c release, caspase-3 and ROCKI activation and it is unaffected in platelets isolated from CypD knock out mice or in platelets treated with cyclosporine A prior to activation. Caspase-3 inhibitor (z-DVED-fmk and ROCK1 inhibitor Y-27632 reduced ABT-737 induced phosphatidylserine expression. Our results also show that activation-induced phosphatidylserine exposure is dependent on mitochondrial membrane depolarization and CypD but is independent of cytochrome c release or caspase-3 or ROCK1 activation. In contrast, the phosphatidylserine exposure in stored platelets occurs via mitochondrial cytochrome c release, caspase-3 activation and ROCKI activation and does not depend on mitochondrial membrane depolarization or CypD. Disclosures: No relevant conflicts of interest to declare.


2007 ◽  
Vol 18 (1) ◽  
pp. 84-93 ◽  
Author(s):  
Ajoy K. Samraj ◽  
Dennis Sohn ◽  
Klaus Schulze-Osthoff ◽  
Ingo Schmitz

Caspase-9 plays an important role in apoptosis induced by genotoxic stress. Irradiation and anticancer drugs trigger mitochondrial outer membrane permeabilization, resulting in cytochrome c release and caspase-9 activation. Two highly contentious issues, however, remain: It is unclear whether the loss of the mitochondrial membrane potential ΔΨMcontributes to cytochrome c release and whether caspases are involved. Moreover, an unresolved question is whether caspase-2 functions as an initiator in genotoxic stress-induced apoptosis. In the present study, we have identified a mutant Jurkat T-cell line that is deficient in caspase-9 and resistant to apoptosis. Anticancer drugs, however, could activate proapoptotic Bcl-2 proteins and cytochrome c release, similarly as in caspase-9–proficient cells. Interestingly, despite these alterations, the cells retained ΔΨM. Furthermore, processing and enzyme activity of caspase-2 were not observed in the absence of caspase-9. Reconstitution of caspase-9 expression restored not only apoptosis but also the loss of ΔΨMand caspase-2 activity. Thus, we provide genetic evidence that caspase-9 is indispensable for drug-induced apoptosis in cancer cells. Moreover, loss of ΔΨMcan be functionally separated from cytochrome c release. Caspase-9 is not only required for ΔΨMloss but also for caspase-2 activation, suggesting that these two events are downstream of the apoptosome.


2001 ◽  
Vol 281 (4) ◽  
pp. L887-L894 ◽  
Author(s):  
Stefanie Krick ◽  
Oleksandr Platoshyn ◽  
Sharon S. McDaniel ◽  
Lewis J. Rubin ◽  
Jason X.-J. Yuan

The balance between apoptosis and proliferation in pulmonary artery smooth muscle cells (PASMCs) is important in maintaining normal pulmonary vascular structure. Activity of voltage-gated K+ (KV) channels has been demonstrated to regulate cell apoptosis and proliferation. Treatment of PASMCs with staurosporine (ST) induced apoptosis in PASMCs, augmented KV current [ I K(V)], and induced mitochondrial membrane depolarization. High K+ (40 mM) negligibly affected the ST-induced mitochondrial membrane depolarization but inhibited the ST-induced I K(V) increase and apoptosis. Blockade of KV channels with 4-aminopyridine diminished I K(V) and markedly decreased the ST-mediated apoptosis. Furthermore, the ST-induced apoptosis was preceded by the increase in I K(V). These results indicate that ST induces PASMC apoptosis by activation of plasmalemmal KV channels and mitochondrial membrane depolarization. The increased I K(V) would result in an apoptotic volume decrease due to a loss of cytosolic K+ and induce apoptosis. The mitochondrial membrane depolarization would cause cytochrome c release, activate the cytosolic caspases, and induce apoptosis. Inhibition of KV channels would thus attenuate PASMC apoptosis.


Blood ◽  
2001 ◽  
Vol 98 (7) ◽  
pp. 2239-2247 ◽  
Author(s):  
Grant Dewson ◽  
Gerald M. Cohen ◽  
Andrew J. Wardlaw

The apoptosis and subsequent clearance of eosinophils without histotoxic mediator release is thought to be crucial in the resolution of airway inflammation in asthma. Interleukin-5 (IL-5) is a potent suppressor of eosinophil apoptosis. The mechanism by which IL-5 inhibits spontaneous eosinophil apoptosis was investigated. Freshly isolated eosinophils constitutively expressed the conformationally active form of Bax in the cytosol and nucleus. During spontaneous and staurosporine-induced apoptosis, Bax underwent a caspase-independent translocation to the mitochondria, which was inhibited by IL-5. Eosinophil apoptosis was associated with the release of cytochrome c from the mitochondria, which was also inhibited by IL-5. IL-5 and the cell-permeable caspase inhibitor, benzyloxycarbonyl-Val-Ala-Asp-(OMe) fluoromethyl ketone (z-VAD.fmk), prevented phosphatidylserine (PS) externalization, although only IL-5 inhibited loss of mitochondrial membrane potential (ΔΨm). Peripheral blood eosinophils endogenously expressed “initiator” caspase-8 and -9, and “effector” caspase-3, -6, and -7. Spontaneous eosinophil apoptosis was associated with processing of caspase-3, -6, -7, -8, and -9. IL-5 and z-VAD.fmk prevented caspase activation in spontaneous apoptosis. The results suggest that spontaneous eosinophil apoptosis involves Bax translocation to the mitochondria, cytochrome crelease, caspase-independent perturbation of the mitochondrial membrane, and subsequent activation of caspases. IL-5 inhibits spontaneous eosinophil apoptosis at a site upstream of Bax translocation.


Blood ◽  
2001 ◽  
Vol 97 (5) ◽  
pp. 1378-1387 ◽  
Author(s):  
Thomas Wieder ◽  
Frank Essmann ◽  
Aram Prokop ◽  
Karin Schmelz ◽  
Klaus Schulze-Osthoff ◽  
...  

The activation of caspase-8, a crucial upstream mediator of death receptor signaling, was investigated in epirubicin- and Taxol-induced apoptosis of B-lymphoma cells. This study was performed because the CD95/Fas receptor-ligand interaction, recruitment of the Fas-associated death domain (FADD) adaptor protein, and subsequent activation of procaspase-8 have been implicated in the execution of drug-induced apoptosis in other cell types. Indeed, active caspase-8 was readily detected after treatment of mature and immature B-lymphoid cells with epirubicin or Taxol. However, neither constitutive nor drug-induced expression of the CD95/Fas ligand was detectable in B-lymphoma cells. Furthermore, overexpression of a dominant-negative FADD mutant (FADDdn) did not block caspase-8 processing and subsequent DNA fragmentation, indicating that drug-induced caspase-8 activation was mediated by a CD95/Fas-independent mechanism. Instead, caspase-8 cleavage was slightly preceded by activation of caspase-3, suggesting that drug-induced caspase-8 activation in B-lymphoma cells is a downstream event mediated by other caspases. This assumption was confirmed in 2 experimental systems—zDEVD-fmk, a cell-permeable inhibitor of caspase-3–like activity, blocked drug-induced caspase-8 cleavage, and depletion of caspase-3 from cell extracts impaired caspase-8 cleavage after in vitro activation with dATP and cytochrome c. Thus, these data indicate that drug-induced caspase-8 activation in B-lymphoma cells is independent of death receptor signaling and is mediated by postmitochondrial caspase-3 activation.


1995 ◽  
Vol 25 (5) ◽  
pp. 1352-1357 ◽  
Author(s):  
Michael S. K. Choi ◽  
Lawrence H. Boise ◽  
Alexander R. Gottschalk ◽  
José Quintans ◽  
Craig B. Thompson ◽  
...  

2005 ◽  
Vol 102 (6) ◽  
pp. 1147-1157 ◽  
Author(s):  
Torsten Loop ◽  
David Dovi-Akue ◽  
Michael Frick ◽  
Martin Roesslein ◽  
Lotti Egger ◽  
...  

Background Volatile anesthetics modulate lymphocyte function during surgery, and this compromises postoperative immune competence. The current work was undertaken to examine whether volatile anesthetics induce apoptosis in human T lymphocytes and what apoptotic signaling pathway might be used. Methods Effects of sevoflurane, isoflurane, and desflurane were studied in primary human CD3 T lymphocytes and Jurkat T cells in vitro. Apoptosis and mitochondrial membrane potential were assessed using flow cytometry after green fluorescent protein-annexin V and DiOC6-fluorochrome staining. Activity and proteolytic processing of caspase 3 was measured by cleaving of the fluorogenic effector caspase substrate Ac-DEVD-AMC and by anti-caspase-3 Western blotting. Release of mitochondrial cytochrome c was studied after cell fractionation using anti-cytochrome c Western blotting and enzyme-linked immunosorbent assays. Results Sevoflurane and isoflurane induced apoptosis in human T lymphocytes in a dose-dependent manner. By contrast, desflurane did not exert any proapoptotic effects. The apoptotic signaling pathway used by sevoflurane involved disruption of the mitochondrial membrane potential and release of cytochrome c from mitochondria to the cytosol. In addition, the authors observed a proteolytic cleavage of the inactive p32 procaspase 3 to the active p17 fragment, increased caspase-3-like activity, and cleavage of the caspase-3 substrate poly-ADP-ribose-polymerase. Sevoflurane-induced apoptosis was blocked by the general caspase inhibitor Z-VAD.fmk. Death signaling was not mediated via the Fas/CD95 receptor pathway because neither anti-Fas/CD95 receptor antagonism nor FADD deficiency or caspase-8 deficiency were able to attenuate sevoflurane-mediated apoptosis. Conclusion Sevoflurane and isoflurane induce apoptosis in T lymphocytes via increased mitochondrial membrane permeability and caspase-3 activation, but independently of death receptor signaling.


2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Yu Wang ◽  
Chunhui Xia ◽  
Wei Chen ◽  
Yuhang Chen ◽  
Yiyi Wang ◽  
...  

Photodynamic therapy (PDT) is a novel and promising antitumor treatment. Our previous study showed that hydrophilic/lipophilic tetra-α-(4-carboxyphenoxy) phthalocyanine zinc- (TαPcZn-) mediated PDT (TαPcZn-PDT) inhibits the proliferation of human hepatocellular carcinoma Bel-7402 cells by triggering apoptosis and arresting cell cycle. However, mechanisms of TαPcZn-PDT-induced apoptosis of Bel-7402 cells have not been fully clarified. In the present study, therefore, effect of TαPcZn-PDT on apoptosis, P38MAPK, p-P38MAPK, Caspase-8, Caspase-3, Bcl-2, Bid, Cytochrome c, and mitochondria membrane potential in Bel-7402 cells without or with P38MAPK inhibitor SB203580 or Caspase-8 inhibitor Ac-IEFD-CHO was investigated by haematoxylin and eosin (HE) staining assay, flow cytometry analysis of annexin V-FITC/propidium iodide (PI) double staining cells and 5,5′,6,6′-tetrachloro-1,1′,3,3′-tetraethylbenzimidazolylcarbocyanine iodide (JC-1), and immunoblot assay. We found that TαPcZn-PDT resulted in apoptosis induction, activation of P38MAPK, Caspase-8, Caspase-3, and Bid, downregulation of Bcl-2, release of Cytochrome c from mitochondria, and disruption of mitochondrial membrane potential in TαPcZn-PDT-treated Bel-7402 cells. In contrast, SB203580 or Ac-IEFD-CHO attenuated induction of apoptosis, activation of P38MAPK, Caspase-8, Caspase-3, and Bid, downregulation of Bcl-2, release of Cytochrome c from mitochondria, and disruption of mitochondrial membrane potential in TαPcZn-PDT-treated Bel-7402 cells. Taken together, we conclude that Caspase-3, Bcl-2, Bid, and mitochondria are involved in autoregulatory feedback of P38MAPK/Caspase-8 during TαPcZn-PDT-induced apoptosis of Bel-7402 cells.


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