101
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Sawai H, Domae N. Release of cytochrome c from mitochondria precedes Bax translocation/activation in Triton X-100-induced apoptosis. Leuk Res 2008; 32:445-53. [PMID: 17689609 DOI: 10.1016/j.leukres.2007.06.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2007] [Revised: 06/26/2007] [Accepted: 06/26/2007] [Indexed: 11/27/2022]
Abstract
The precise mechanisms by which sublytic concentrations of detergents induce apoptosis remain unclear. Recent studies reported the ability of nonionic detergents such as Triton X-100 to induce conformational change of Bax to the active form in vitro. Here we investigated whether activation of Bax might play a role in Triton X-100-induced apoptosis in cells. Although Bax translocation/activation was inhibited by caspase inhibitors, cytochrome c release from mitochondria was not affected in Triton X-100-induced apoptosis in U-937 cells. These results demonstrate that translocation/activation of Bax occurs downstream of cytochrome c release and caspase activation in Triton X-100-induced apoptosis.
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Affiliation(s)
- Hirofumi Sawai
- Department of Internal Medicine, Osaka Dental University, 8-1 Kuzuhahanazonocho, Hirakata, Osaka 573-1121, Japan.
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102
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ZHAO YONGGE, DIFRANCESCA DANIELL, WANG XUE, ZARNEGAR REZA, MICHALOPOULOS GEORGEK, YIN XIAOMING. Promotion of Fas-mediated apoptosis in Type II cells by high doses of hepatocyte growth factor bypasses the mitochondrial requirement. J Cell Physiol 2008; 213:556-63. [PMID: 17620325 PMCID: PMC2636794 DOI: 10.1002/jcp.21136] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The death receptor pathway is coupled to the mitochondria apoptosis pathway. However, mitochondrial participation, which is stimulated by Bid but suppressed by Bcl-2/Bcl-x(L), is required in certain cells (Type II), but not in others (Type I). While these differences were originally characterized in the lymphoid cell lines, the typical Type II cells are represented by hepatocytes in vivo. The molecular mechanisms that distinguish Type II from Type I cells and the regulation are not fully understood. Fas can be sequestered by the HGF receptor c-Met and high doses of HGF can promote cell death by freeing Fas from c-Met complex. We thus reasoned that treatment of the Type II cells with high doses of HGF could enhance Fas-mediated apoptosis and spare the mitochondria amplification. Indeed, such treatment led to increased apoptosis in Type II lymphoid cells, which could not be blocked by Bcl-x(L). Moreover, significant hepatocyte apoptosis was induced by this scheme in the absence of Bid with increased dissociation of Fas from c-Met. These findings indicate that high doses of HGF could be used to promote apoptosis in Type II cells bypassing the requirement for mitochondria activation.
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Affiliation(s)
- YONGGE ZHAO
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - DANIELL DIFRANCESCA
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - XUE WANG
- Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - REZA ZARNEGAR
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - GEORGE K. MICHALOPOULOS
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - XIAO-MING YIN
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
- Correspondence to: Xiao-Ming Yin, Department of Pathology, University of Pittsburgh School of Medicine, 7th Floor, Scaife Hall, Room S739, 3550 Terrace Street, Pittsburgh, PA 15261. E-mail:
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103
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Du J, Di HS, Guo L, Li ZH, Wang GL. Hyperthermia causes bovine mammary epithelial cell death by a mitochondrial-induced pathway. J Therm Biol 2008. [DOI: 10.1016/j.jtherbio.2007.06.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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104
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Djerbi M, Malinowski MM, Yagita H, Zhivotovsky B, Grandien A. Participation of FLIP, RIP and Bcl-x(L) in Fas-mediated T-cell death. Scand J Immunol 2007; 66:410-21. [PMID: 17850585 DOI: 10.1111/j.1365-3083.2007.01957.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Apart from the conventional Fas signalling pathway, alternative pathways including the mitochondrial caspase-dependent and RIP-mediated cell death routes have been proposed to operate during Fas-mediated cell death. To evaluate the contribution of different Fas signalling pathways, mice overexpressing FLIP(L), Bcl-x(L), a kinase-deficient form of RIP (RIPDeltakin) or combinations thereof were generated by retroviral gene transfer of haematopoietic stem cells. Such mice did not show overt abnormalities in haematopoietic development, defects in thymic deletion, accumulation of double-negative T cells or signs of autoimmunity. Fas-mediated death of mitogen-activated T cells was caspase dependent and could be blocked by FLIP(L) overexpression only with the minor involvement of Bcl-x(L) or RIPDeltakin inhibitable pathways. Fas-mediated death of resting CD4(+) and CD8(+) T cells was mainly caspase dependent but could only partly be blocked by FLIP(L) overexpression. Both Bcl-x(L) or RIPDeltakin expression resulted in partial protection of CD8(+) T cells against Fas-mediated cell death. These results indicate that yet uncharacterized signalling pathways from the Fas receptor are critically involved in lymphoproliferative and autoimmune disease observed in lpr mice and autoimmune lymphoproliferative syndrome patients.
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Affiliation(s)
- M Djerbi
- Department of Immunology, The Wenner-Gren Institute, University of Stockholm, Stockholm, Sweden
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105
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AK2 activates a novel apoptotic pathway through formation of a complex with FADD and caspase-10. Nat Cell Biol 2007; 9:1303-10. [PMID: 17952061 DOI: 10.1038/ncb1650] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2007] [Accepted: 09/07/2007] [Indexed: 02/07/2023]
Abstract
Mitochondrial proteins function as essential regulators in apoptosis. Here, we show that mitochondrial adenylate kinase 2 (AK2) mediates mitochondrial apoptosis through the formation of an AK2-FADD-caspase-10 (AFAC10) complex. Downregulation of AK2 attenuates etoposide- or staurosporine-induced apoptosis in human cells, but not that induced by tumour-necrosis-factor-related apoptosis-inducing ligand (TRAIL) or Fas ligand (FasL). During intrinsic apoptosis, AK2 translocates to the cytoplasm, whereas this event is diminished in Apaf-1 knockdown cells and prevented by Bcl-2 or Bcl-X(L). Addition of purified AK2 protein to cell extracts first induces activation of caspase-10 via FADD and subsequently caspase-3 activation, but does not affect caspase-8. AFAC10 complexes are detected in cells undergoing intrinsic cell death and AK2 promotes the association of caspase-10 with FADD. In contrast, AFAC10 complexes are not detected in several etoposide-resistant human tumour cell lines. Taken together, these results suggest that, acting in concert with FADD and caspase-10, AK2 mediates a novel intrinsic apoptotic pathway that may be involved in tumorigenesis.
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106
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Constituents of Brazilian red propolis and their preferential cytotoxic activity against human pancreatic PANC-1 cancer cell line in nutrient-deprived condition. Bioorg Med Chem 2007; 16:181-9. [PMID: 17950610 DOI: 10.1016/j.bmc.2007.10.004] [Citation(s) in RCA: 118] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2007] [Revised: 09/18/2007] [Accepted: 10/02/2007] [Indexed: 12/18/2022]
Abstract
Human pancreatic cancer cells such as PANC-1 are known to exhibit marked tolerance to nutrition starvation that enables them to survive for prolonged period of time even under extremely nutrient-deprived conditions. Thus, elimination of this tolerance to nutrition starvation is regarded as a novel approach in anticancer drug development. In this study, the MeOH soluble extract of Brazilian red propolis was found to kill 100% PANC-1 cells preferentially in the nutrient-deprived condition at the concentration of 10 microg/mL. Further phytochemical investigation led to the isolation of 43 compounds including three new compounds, (6aS,11aS)-6a-ethoxymedicarpan (1), 2-(2',4'-dihydroxyphenyl)-3-methyl-6-methoxybenzofuran (2), and 2,6-dihydroxy-2-[(4-hydroxyphenyl)methyl]-3-benzofuranone (3). Among them, (6aR,11aR)-3,8-dihydroxy-9-methoxypterocarpan (21, DMPC) displayed the most potent 100% preferential cytotoxicity (PC(100)) at the concentration of 12.5 microM. Further study on the mode of cell death induced by DMPC against PANC-1 cells indicated that killing process was not accompanied by DNA fragmentation, rather through a nonapoptotic pathway accompanied by necrotic-type morphological changes.
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107
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Festjens N, Vanden Berghe T, Cornelis S, Vandenabeele P. RIP1, a kinase on the crossroads of a cell's decision to live or die. Cell Death Differ 2007; 14:400-10. [PMID: 17301840 DOI: 10.1038/sj.cdd.4402085] [Citation(s) in RCA: 353] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Binding of inflammatory cytokines to their receptors, stimulation of pathogen recognition receptors by pathogen-associated molecular patterns, and DNA damage induce specific signalling events. A cell that is exposed to these signals can respond by activation of NF-kappaB, mitogen-activated protein kinases and interferon regulatory factors, resulting in the upregulation of antiapoptotic proteins and of several cytokines. The consequent survival may or may not be accompanied by an inflammatory response. Alternatively, a cell can also activate death-signalling pathways, resulting in apoptosis or alternative cell death such as necrosis or autophagic cell death. Interplay between survival and death-promoting complexes continues as they compete with each other until one eventually dominates and determines the cell's fate. RIP1 is a crucial adaptor kinase on the crossroad of these stress-induced signalling pathways and a cell's decision to live or die. Following different upstream signals, particular RIP1-containing complexes are formed; these initiate only a limited number of cellular responses. In this review, we describe how RIP1 acts as a key integrator of signalling pathways initiated by stimulation of death receptors, bacterial or viral infection, genotoxic stress and T-cell homeostasis.
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Affiliation(s)
- N Festjens
- Molecular Signalling and Cell Death Unit, Department for Molecular Biomedical Research, VIB and Ghent University, Ghent, Belgium
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108
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May MJ, Madge LA. Caspase inhibition sensitizes inhibitor of NF-kappaB kinase beta-deficient fibroblasts to caspase-independent cell death via the generation of reactive oxygen species. J Biol Chem 2007; 282:16105-16. [PMID: 17430892 PMCID: PMC2895319 DOI: 10.1074/jbc.m611115200] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Cells lacking functional NF-kappaB die after ligation of some tumor necrosis factor (TNF) receptor family members through failure to express NF-kappaB-dependent anti-apoptotic genes. NF-kappaB activation requires the IkappaB kinase (IKK) complex containing two catalytic subunits named IKKalpha and IKKbeta that regulate distinct NF-kappaB pathways. IKKbeta is critical for classical signaling that induces pro-inflammatory and anti-apoptotic gene profiles, whereas IKKalpha regulates the non-canonical pathway involved in lymphoid organogenesis and B-cell development. To determine whether IKKalpha and IKKbeta differentially function in rescuing cells from death induced by activators of the classical and non-canonical pathways, we analyzed death after ligation of the TNF and lymphotoxin-beta receptors, respectively. Using murine embryonic fibroblasts (MEFs) lacking each of the IKKs, the caspase inhibitor benzyloxycarbonyl-Val-Ala-Asp-fluoromethyl ketone, and dominant negative Fas-associated death domain protein, we found that deletion of these kinases sensitized MEFs to distinct cell death pathways. MEFs lacking IKKalpha were sensitized to death in response to both cytokines that was entirely caspase-dependent, demonstrating that IKKalpha functions in this process. Surprisingly, death of IKKbeta-/- MEFs was not blocked by caspase inhibition, demonstrating that IKKbeta negatively regulates caspase-independent cell death (CICD). CICD was strongly activated by both TNF and lymphotoxin-beta receptor ligation in IKKbeta-/- MEFs and was accompanied by loss of mitochondrial membrane potential and the generation of reactive oxygen species. CICD was inhibited by the anti-oxidant butylated hydroxyanosole and overexpression of Bcl-2, neither of which blocked caspase-dependent apoptosis. Our findings, therefore, demonstrate that both IKKalpha and IKKbeta regulate cytokine-induced apoptosis, and IKKbeta additionally represses reactive oxygen species- and mitochondrial-dependent CICD.
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Affiliation(s)
- Michael J May
- Department of Animal Biology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, Pennsylvania 19104, USA.
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109
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Sakamaki K, Nozaki M, Kominami K, Satou Y. The evolutionary conservation of the core components necessary for the extrinsic apoptotic signaling pathway, in Medaka fish. BMC Genomics 2007; 8:141. [PMID: 17540041 PMCID: PMC1903365 DOI: 10.1186/1471-2164-8-141] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2007] [Accepted: 06/01/2007] [Indexed: 12/24/2022] Open
Abstract
Background Death receptors on the cell surface and the interacting cytosolic molecules, adaptors and initiator caspases, are essential as core components of the extrinsic apoptotic signaling pathway. While the apoptotic machinery governing the extrinsic signaling pathway is well characterized in mammals, it is not fully understood in fish. Results We identified and characterized orthologs of mammalian Fas, FADD and caspase-8 that correspond to the death receptor, adaptor and initiator caspase, from the Medaka fish (Oryzias latipes). Medaka Fas, caspase-8 and FADD exhibited protein structures similar to that of their mammalian counterparts, containing a death domain (DD), a death effector domain (DED) or both. Functional analyses indicated that these molecules possess killing activity in mammalian cell lines upon overexpression or following activation by apoptotic stimuli, suggesting similar pro-apoptotic functions in the extrinsic pathway as those in mammals. Genomic sequence analysis revealed that the Medaka fas (tnfrsf6), fadd and caspase-8 (casp8) genes are organized in a similar genomic structure as the mammalian genes. Database search and phylogenetic analysis revealed that the fas gene, but not the fadd and casp8 genes, appear to be present only in vertebrates. Conclusion Our results indicate that the core components necessary for the extrinsic apoptotic pathway are evolutionarily conserved in function and structure across vertebrate species. Based on these results, we presume the mechanism of apoptosis induction via death receptors was evolutionarily established during the appearance of vertebrates.
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MESH Headings
- Amino Acid Sequence
- Animals
- Apoptosis
- Base Sequence
- Caspase 8/chemistry
- Caspase 8/genetics
- Caspase 8/metabolism
- Cells, Cultured
- DNA, Complementary
- Databases, Genetic
- Embryo, Mammalian
- Embryo, Nonmammalian
- Evolution, Molecular
- Exons
- Expressed Sequence Tags
- Fas Ligand Protein/chemistry
- Fas Ligand Protein/genetics
- Fas Ligand Protein/metabolism
- Fas-Associated Death Domain Protein/chemistry
- Fas-Associated Death Domain Protein/genetics
- Fas-Associated Death Domain Protein/metabolism
- Fibroblasts/cytology
- Fibroblasts/metabolism
- Fluorescent Antibody Technique, Indirect
- Genome
- HeLa Cells
- Humans
- Immunohistochemistry
- Mice
- Molecular Sequence Data
- NIH 3T3 Cells
- Open Reading Frames
- Oryzias/genetics
- Oryzias/metabolism
- Phylogeny
- Protein Structure, Tertiary
- Receptors, Death Domain/chemistry
- Receptors, Death Domain/genetics
- Receptors, Death Domain/metabolism
- Sequence Analysis, DNA
- Sequence Homology, Amino Acid
- Signal Transduction
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Affiliation(s)
- Kazuhiro Sakamaki
- Department of Animal Development and Physiology, Graduate School of Biostudies, Kyoto University, Kyoto 606-8501, Japan
| | - Masami Nozaki
- Department of Cell Biology, Research Institute for Microbial Diseases, Osaka University, Suita 565-0871, Japan
| | - Katsuya Kominami
- Department of Animal Development and Physiology, Graduate School of Biostudies, Kyoto University, Kyoto 606-8501, Japan
- Present address: Nihon Schering Research Center, Kobe 650-0047, Japan
| | - Yutaka Satou
- Department of Zoology, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
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110
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Wattiaux R, Wattiaux-de Coninck S, Thirion J, Gasingirwa MC, Jadot M. Lysosomes and Fas-mediated liver cell death. Biochem J 2007; 403:89-95. [PMID: 17129211 PMCID: PMC1828900 DOI: 10.1042/bj20061738] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A number of studies, mostly performed ex vivo, suggest that lysosomes are involved in apoptosis as a result of a release of their cathepsins into the cytosol. These enzymes could then contribute to the permeabilization of the outer mitochondrial membrane; they could also activate effector caspases. The present study aims at testing whether the membrane of liver lysosomes is disrupted during Fas-mediated cell death of hepatocytes in vivo, a process implicated in several liver pathologies. Apoptosis was induced by injecting mice with aFas (anti-Fas antibody). The state of lysosomes was assessed by determining the proportion of lysosomal enzymes (beta-galactosidase, beta-glucuronidase, cathepsin C and cathepsin B) present in homogenate supernatants, devoid of intact lysosomes, and by analysing the behaviour in differential and isopycnic centrifugation of beta-galactosidase. Apoptosis was monitored by measuring caspase 3 activity (DEVDase) and the release of sulfite cytochrome c reductase, an enzyme located in the mitochondrial intermembrane space. Results show that an injection of 10 microg of aFas causes a rapid and large increase in DEVDase activity and in unsedimentable sulfite cytochrome c reductase. This modifies neither the proportion of unsedimentable lysosomal enzyme in the homogenates nor the behaviour of lysosomes in centrifugation. Experiments performed with a lower dose of aFas (5 microg) indicate that unsedimentable lysosomal hydrolase activity increases in the homogenate after injection but with a marked delay with respect to the increase in DEVDase activity and in unsedimentable sulfite cytochrome c reductase. Comparative experiments ex vivo performed with Jurkat cells show an increase in unsedimentable lysosomal hydrolases, but much later than caspase 3 activation, and a release of dipeptidyl peptidase III and DEVDase into culture medium. It is proposed that the weakening of lysosomes observed after aFas treatment in vivo and ex vivo results from a necrotic process that takes place late after initiation of apoptosis.
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Affiliation(s)
- Robert Wattiaux
- Laboratoire de Chimie Physiologique, URPhiM, FUNDP (Facultés Universitaires Notre-Dame de la Paix), 61 rue de Bruxelles, 5000 Namur, Belgium.
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111
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Tijerina M, Kopec̆ková P, Kopec̆ek J. Mechanisms of Cytotoxicity in Human Ovarian Carcinoma Cells Exposed to Free Mce6 or HPMA Copolymer-Mce6 Conjugates¶. Photochem Photobiol 2007. [DOI: 10.1562/0031-8655(2003)0770645mociho2.0.co2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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112
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Matsumoto N, Imamura R, Suda T. Caspase-8- and JNK-dependent AP-1 activation is required for Fas ligand-induced IL-8 production. FEBS J 2007; 274:2376-84. [PMID: 17403042 DOI: 10.1111/j.1742-4658.2007.05772.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Despite a dogma that apoptosis does not induce inflammation, Fas ligand (FasL), a well-known death factor, possesses pro-inflammatory activity. For example, FasL induces nuclear factor kappaB (NF-kappaB) activity and interleukin 8 (IL-8) production by engagement of Fas in human cells. Here, we found that a dominant negative mutant of c-Jun, a component of the activator protein-1 (AP-1) transcription factor, inhibits FasL-induced AP-1 activity and IL-8 production in HEK293 cells. Selective inhibition of AP-1 did not affect NF-kappaB activation and vice versa, indicating that their activations were not sequential events. The FasL-induced AP-1 activation could be inhibited by deleting or introducing the lymphoproliferation (lpr)-type point mutation into the Fas death domain (DD), knocking down the Fas-associated DD protein (FADD), abrogating caspase-8 expression with small interfering RNAs, or using inhibitors for pan-caspase and caspase-8 but not caspase-1 or caspase-3. Furthermore, wildtype, but not a catalytically inactive mutant, of caspase-8 reconstituted the FasL-induced AP-1 activation in caspase-8-deficient cells. Fas ligand induced the phosphorylation of two of the three major mitogen-activated protein kinases (MAPKs): extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK) but not p38 MAPK. Unexpectedly, an inhibitor for JNK but not for MAPK/ERK kinase inhibited the FasL-induced AP-1 activation and IL-8 production. These results demonstrate that FasL-induced AP-1 activation is required for optimal IL-8 production, and this process is mediated by FADD, caspase-8, and JNK.
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Affiliation(s)
- Norihiko Matsumoto
- Division of Immunology and Molecular Biology, Cancer Research Institute, Kanazawa University, Japan
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113
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Sakata SI, Yan Y, Satou Y, Momoi A, Ngo-Hazelett P, Nozaki M, Furutani-Seiki M, Postlethwait JH, Yonehara S, Sakamaki K. Conserved function of caspase-8 in apoptosis during bony fish evolution. Gene 2007; 396:134-48. [PMID: 17459614 PMCID: PMC2064871 DOI: 10.1016/j.gene.2007.03.010] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2006] [Revised: 02/24/2007] [Accepted: 03/14/2007] [Indexed: 11/19/2022]
Abstract
Caspase-8, a member of the caspase family, plays an important role in apoptotic signal transduction in mammals. Here we report the identification and characterization of the caspase-8 (casp8) gene in the zebrafish Danio rerio. The zebrafish casp8 gene has a genomic organization similar to mammalian casp8 genes, consisting of 10 exons. By chromosome mapping, we found that casp8 maps on linkage group 6 (LG6), a zebrafish chromosome segment orthologous to the long arm of human Chr. 2, which carries CASP8. In contrast, the zebrafish casp10-like gene and the cflar gene separately localize on LG9 and LG11, respectively, and these genes form a cluster with CASP8 on the human chromosome. This chromosomal segregation is unique to fish but not other vertebrates. Furthermore, we examined the function of zebrafish Casp8 protein in mammalian cells, and showed that it has pro-apoptotic activity when overexpressed. In addition, this molecule was capable of transmitting apoptotic signals mediated through not only Fas but also the TNF receptor in mouse Casp8-deficient cells. Expression analysis showed that casp8 is maternally expressed, and transcripts continue to be present throughout embryogenesis and into larval stages. These results show that zebrafish casp8 has a structure and function similar to mammalian CASP8 orthologs, and our study suggests that the role of caspase-8 in the apoptotic signal pathway has been conserved over at least 450 million years of vertebrate evolution.
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Affiliation(s)
- Shin-ichi Sakata
- Department of Animal Development and Physiology, Graduate School of Biostudies, Kyoto University, Kyoto 606-8501, Japan
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114
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Kalai M, Suin V, Festjens N, Meeus A, Bernis A, Wang XM, Saelens X, Vandenabeele P. The caspase-generated fragments of PKR cooperate to activate full-length PKR and inhibit translation. Cell Death Differ 2007; 14:1050-9. [PMID: 17318221 DOI: 10.1038/sj.cdd.4402110] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
We have studied the involvement of receptor interacting protein kinase-1 (RIP1) and dsRNA-activated protein kinase (PKR) in external dsRNA-induced apoptotic and necrotic cell death in Jurkat T cell lymphoma. Our results suggest that RIP1 plays an imported role in dsRNA-induced apoptosis and necrosis. We demonstrated that contrary to necrosis, protein synthesis is inhibited in apoptosis. Here, we show that phosphorylation of translation initiation factor 2-alpha (eukaryotic initiation factor 2-alpha (eIF2-alpha)) and its kinase, PKR, occur in dsRNA-induced apoptosis but not in necrosis. These events are caspase-dependent and coincide with the appearance of the caspase-mediated PKR fragments, N-terminal domain (ND) and kinase domain (KD). Our immunoprecipitation experiments demonstrated that both fragments could independently co-precipitate with full-length PKR. Expression of PKR-KD leads to PKR and eIF2-alpha phosphorylation and inhibits protein translation, whereas that of PKR-ND does not. Co-expression of PKR-ND and PKR-KD promotes their interaction with PKR, PKR and eIF2-alpha phosphorylation and suppresses protein translation better than PKR-KD alone. Our findings suggest a caspase-dependent mode of activation of PKR in apoptosis in which the PKR-KD fragment interacts with and activates intact PKR. PKR-ND facilitates the interaction of PKR-KD with full-length PKR and thus the activation of the kinase and amplifies the translation inhibitory signal.
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Affiliation(s)
- M Kalai
- Laboratory of Cellular Microbiology, Pasteur Institute, Rue Engeland, Brussels, Belgium.
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115
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Wang K, Li J, Degterev A, Hsu E, Yuan J, Yuan C. Structure-activity relationship analysis of a novel necroptosis inhibitor, Necrostatin-5. Bioorg Med Chem Lett 2006; 17:1455-65. [PMID: 17270434 DOI: 10.1016/j.bmcl.2006.11.056] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2006] [Revised: 10/12/2006] [Accepted: 11/07/2006] [Indexed: 11/25/2022]
Abstract
Necrostatin-5 (Nec-5) is a novel potent small-molecule inhibitor of necroptosis structurally distinct from previously described Necrostatin-1 (Nec-1), and therefore, represents a new direction for the inhibition of this cellular caspase-independent necrotic cell death mechanism. Here, we describe a series of structural modifications of Nec-5 and the structure-activity relationship (SAR) of Nec-5 series in inhibiting necroptosis.
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Affiliation(s)
- Ke Wang
- State Key Laboratory of Bio-organic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China
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116
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Festjens N, Vanden Berghe T, Vandenabeele P. Necrosis, a well-orchestrated form of cell demise: signalling cascades, important mediators and concomitant immune response. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2006; 1757:1371-87. [PMID: 16950166 DOI: 10.1016/j.bbabio.2006.06.014] [Citation(s) in RCA: 469] [Impact Index Per Article: 26.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2006] [Revised: 06/15/2006] [Accepted: 06/20/2006] [Indexed: 12/13/2022]
Abstract
Necrosis has long been described as a consequence of physico-chemical stress and thus accidental and uncontrolled. Recently, it is becoming clear that necrotic cell death is as well controlled and programmed as caspase-dependent apoptosis, and that it may be an important cell death mode that is both pathologically and physiologically relevant. Necrotic cell death is not the result of one well-described signalling cascade but is the consequence of extensive crosstalk between several biochemical and molecular events at different cellular levels. Recent data indicate that serine/threonine kinase RIP1, which contains a death domain, may act as a central initiator. Calcium and reactive oxygen species (ROS) are main players during the propagation and execution phases of necrotic cell death, directly or indirectly provoking damage to proteins, lipids and DNA, which culminates in disruption of organelle and cell integrity. Necrotically dying cells initiate pro-inflammatory signalling cascades by actively releasing inflammatory cytokines and by spilling their contents when they lyse. Unravelling the signalling cascades contributing to necrotic cell death will permit us to develop tools to specifically interfere with necrosis at certain levels of signalling. Necrosis occurs in both physiological and pathophysiological processes, and is capable of killing tumour cells that have developed strategies to evade apoptosis. Thus detailed knowledge of necrosis may be exploited in therapeutic strategies.
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Affiliation(s)
- Nele Festjens
- Molecular Signalling and Cell Death Unit, Department for Molecular Biomedical Research, VIB and Ghent University, Fiers-Schell-Van Montagu Building, Technologiepark 927, B-9052 Ghent, Belgium
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117
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Golstein P, Kroemer G. Redundant cell death mechanisms as relics and backups. Cell Death Differ 2006; 12 Suppl 2:1490-6. [PMID: 15818403 DOI: 10.1038/sj.cdd.4401607] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Here we review recent observations indicating the existence of redundant cell death mechanisms. We speculate that this redundancy reflects a particular evolutionary history for cellular demise. Autophagic or apoptotic elements might have been added to a primordial death mechanism, initially improving cell dismantling and later acquiring the ability to act themselves as death effectors. The resulting redundancy of cell death mechanisms has pathophysiological implications.
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Affiliation(s)
- P Golstein
- Centre d'Immunologie de Marseille-Luminy, CNRS-INSERM-Université de la Mediterranée, Parc Scientifique de Luminy, Case 906, 13288 Marseille cedex 9, France.
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118
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Haluska P, Carboni JM, Loegering DA, Lee FY, Wittman M, Saulnier MG, Frennesson DB, Kalli KR, Conover CA, Attar RM, Kaufmann SH, Gottardis M, Erlichman C. In vitro and In vivo Antitumor Effects of the Dual Insulin-Like Growth Factor-I/Insulin Receptor Inhibitor, BMS-554417. Cancer Res 2006; 66:362-71. [PMID: 16397250 DOI: 10.1158/0008-5472.can-05-1107] [Citation(s) in RCA: 157] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The insulin-like growth factor receptor (IGF-IR) and insulin receptor are either overactivated and/or overexpressed in a wide range of tumor types and contribute to tumorigenicity, proliferation, metastasis, and drug resistance. Here, we show that BMS-554417, a novel small molecule developed as an inhibitor of IGF-IR, inhibits IGF-IR and insulin receptor kinase activity and proliferation in vitro, and reduces tumor xenograft size in vivo. In a series of carcinoma cell lines, the IC50 for proliferation ranged from 120 nmol/L (Colo205) to >8.5 micromol/L (OV202). The addition of stimulatory ligands was unnecessary for the antiproliferative effect in MCF-7 and OV202 cells. BMS-554417 treatment inhibited IGF-IR and insulin receptor signaling through extracellular signal-related kinase as well as the phosphoinositide 3-kinase/Akt pathway, as evidenced by decreased Akt phosphorylation at Ser473. At doses that inhibited proliferation, the compound also caused a G0-G1 arrest and prevented nuclear accumulation of cyclin D1 in response to LR3 IGF-I. In Jurkat T-cell leukemia cells, this agent triggered apoptotic cell death via the mitochondrial pathway. BMS-554417 was orally bioavailable and significantly inhibited the growth of IGF1R-Sal tumor xenografts in vivo. BMS-554417 is a member of a novel class of IGF-IR/insulin receptor inhibitors that have potential clinical applications because of their antiproliferative and proapoptotic activity in vitro and in vivo.
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Affiliation(s)
- Paul Haluska
- Division of Medical Oncology, Mayo Clinic College of Medicine, Rochester, Minnesota 55905, USA
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119
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Abstract
Organismal homeostasis depends on an intricate balance between cell death and renewal. Early pathologists recognized that this balance could be disrupted by the extensive damage observed in internal organs during the course of certain diseases. This form of tissue damage was termed "necrosis", derived from the Greek "nekros" for corpse. As it became clear that the essential building block of tissue was the cell, necrosis came to be used to describe pathologic cell death. Until recently, necrotic cell death was believed to result from injuries that caused an irreversible bioenergetic compromise. The cell dying by necrosis has been viewed as a victim of extrinsic events beyond its control. However, recent evidence suggests that a cell can initiate its own demise by necrosis in a manner that initiates both inflammatory and/or reparative responses in the host. By initiating these adaptive responses, programmed cell necrosis may serve to maintain tissue and organismal integrity.
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Affiliation(s)
- Wei-Xing Zong
- Department of Molecular Genetics and Microbiology, State University of New York at Stony Brook, New York 11794, USA
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120
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Luo JL, Kamata H, Karin M. The Anti-Death Machinery in IKK/NF-κB Signaling. J Clin Immunol 2005; 25:541-50. [PMID: 16380818 DOI: 10.1007/s10875-005-8217-6] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2005] [Accepted: 08/26/2005] [Indexed: 12/17/2022]
Abstract
The most extensively studied function of NF-kappaB is its ability to promote cell survival through induction of target genes, whose products inhibit various aspects of the apoptotic machinery in both normal and malignant cells. Recent studies, however, indicate that NF-kappaB activation can also suppress programmed necrosis through induction of genes encoding anti-oxidant proteins. Since tumor cells often use NF-kappaB pathway as a shield to escape the killing of conventional anti-cancer therapies, intervention of IKK/NF-kappaB signaling would be a promising option to improve the efficacy of cancer treatment.
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Affiliation(s)
- Jun-Li Luo
- Laboratory of Gene Regulation and Signal Transduction, School of Medicine, University of California-San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
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121
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Hetz CA, Torres V, Quest AFG. Beyond apoptosis: nonapoptotic cell death in physiology and disease. Biochem Cell Biol 2005; 83:579-88. [PMID: 16234846 DOI: 10.1139/o05-065] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Apoptosis is a morphologically defined form of programmed cell death (PCD) that is mediated by the activation of members of the caspase family. Analysis of death-receptor signaling in lymphocytes has revealed that caspase-dependent signaling pathways are also linked to cell death by nonapoptotic mechanisms, indicating that apoptosis is not the only form of PCD. Under physiological and pathological conditions, cells demonstrate a high degree of flexibility in cell-death responses, as is reflected in the existence of a variety of mechanisms, including necrosis-like PCD, autophagy (or type II PCD), and accidental necrosis. In this review, we discuss recent data suggesting that canonical apoptotic pathways, including death-receptor signaling, control caspase-dependent and -independent cell-death pathways.Key words: apoptosis, necrosis, nonapoptotic programmed cell death, death receptors, ceramides.
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Affiliation(s)
- Claudio A Hetz
- Instituto de Ciencias Biomédicas, Universidad de Chile, Santiago, Chile
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122
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Hareramadas B, Rai U. Mechanism of androgen-induced thymic atrophy in the wall lizard, Hemidactylus flaviviridis: an in vitro study. Gen Comp Endocrinol 2005; 144:10-9. [PMID: 16004999 DOI: 10.1016/j.ygcen.2005.04.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2004] [Revised: 04/09/2005] [Accepted: 04/13/2005] [Indexed: 11/16/2022]
Abstract
The present in vitro study demonstrates the effect of androgen on thymocyte apoptosis leading to thymic atrophy in the wall lizard, Hemidactylus flaviviridis. Thymocytes collected from castrated lizards were incubated with varying concentrations of dihydrotestosterone (DHT) to observe its effect on proliferation and apoptosis. DHT treatment reduced the tritiated thymidine incorporation in thymocytes, suggesting that androgen directly inhibits thymocyte proliferation. It also caused apoptosis of thymocytes effectively at 10(-7)M. However, the increased apoptotic action of DHT was indirectly mediated through thymic epithelial cell-rich stromal cell components (TEC). This observation was reaffirmed by in vitro incubation of thymocytes with DHT-pretreated TEC-conditioned medium. However, the DHT-induced TEC-secreted apoptotic factors could induce thymocyte DNA fragmentation only when DHT was added to the conditioned medium. It implies that DHT priming of thymocytes is required for the apoptotic effect of DHT-induced TEC-secreted factor. DHT-induced thymocyte apoptosis was found to be caspase-dependent since it activated the initiator (caspase-9) and effector caspases (caspases-3 and -7) as well as cleaved the enzyme substrate poly(ADP-ribose) polymerase (PARP). Further, the apoptotic effect of DHT was routed through its classical receptors, as non-steroidal antiandrogen flutamide blocked the DHT-induced thymocyte apoptosis. The inhibition of apoptosis by transcription/translation inhibitors further substantiates the genomic pathway of DHT action. It can be concluded that DHT, in addition to inhibiting thymocyte proliferation directly, accelerates caspase-dependent apoptotic process in thymocytes indirectly through TEC via a genomic pathway. Nevertheless, the priming of thymocytes with DHT is required for the apoptotic effect of TEC-secreted factor.
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Affiliation(s)
- B Hareramadas
- Comparative Endocrinology Laboratory, Department of Zoology, University of Delhi (North Campus), Delhi 110 007, India
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123
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Rothstein RP, Levison SW. Gray matter oligodendrocyte progenitors and neurons die caspase-3 mediated deaths subsequent to mild perinatal hypoxic/ischemic insults. Dev Neurosci 2005; 27:149-59. [PMID: 16046849 PMCID: PMC1351040 DOI: 10.1159/000085987] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2004] [Accepted: 03/09/2005] [Indexed: 11/19/2022] Open
Abstract
With significant improvements in neonatal care, fewer infants sustain severe injury as a consequence of hypoxia/ischemia (H/I). However, the majority of experimental studies have inflicted moderate to severe injuries, or they have assessed damage to the caudal forebrain; therefore, to better understand how a mild H/I episode affects the structures and cells of the rostral forebrain, we assessed the relative vulnerabilities of cells in the neocortex, striatum, corpus callosum, choroid plexus and subventricular zone (SVZ). To inflict mild H/I injury, the right common carotid artery was ligated followed by 1 h of hypoxia (8% O(2)) at 37 degrees C. Regional vulnerabilities were assessed using TUNEL, active caspase-3 and hematoxylin and eosin staining at 24 and 48 h of recovery. Scattered columns of cell death were observed in the neocortex with deep-layer neurons more vulnerable than more superficial neurons. The majority of these dying neurons appeared to be dying apoptotic rather than necrotic deaths. In addition, approximately 1/3 of the apoptotic cells in the neocortex were O4+ oligodendrocyte progenitors. We also observed a decrease in NG2 staining within the affected regions of the forebrain. By contrast, active caspase-3+/S-100beta+ astrocytes were not observed. Neurons and O4+ oligodendrocyte progenitors also died apoptotic deaths within the striatum. The lining cells of the choroid plexus also sustained damage. Elevated numbers of apoptotic cells were observed in the most lateral region of the SVZ and some of these dying cells were O4+. The most novel finding of this study, that oligodendrocyte progenitors in the gray matter are damaged and eliminated as a consequence of perinatal H/I, provides new insights into the histopathology and neurological deficits observed in infants who sustain mild H/I brain injuries.
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Affiliation(s)
- Raymond P Rothstein
- Department of Neurology and Neuroscience, Laboratory for Regenerative Neurobiology, UMDNJ-New Jersey Medical School, Newark, NJ, USA
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124
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Hainsworth AH, Bermpohl D, Webb TE, Darwish R, Fiskum G, Qiu J, McCarthy D, Moskowitz MA, Whalen MJ. Expression of cellular FLICE inhibitory proteins (cFLIP) in normal and traumatic murine and human cerebral cortex. J Cereb Blood Flow Metab 2005; 25:1030-40. [PMID: 15815586 PMCID: PMC1266275 DOI: 10.1038/sj.jcbfm.9600104] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Cellular Fas-associated death domain-like interleukin-1-beta converting enzyme (FLICE) inhibitory proteins (cFLIPs) are endogenous caspase homologues that inhibit programmed cell death. We hypothesized that cFLIPs are differentially expressed in response to traumatic brain injury (TBI). cFLIP-alpha and cFLIP-delta mRNA were expressed in normal mouse brain-specifically cFLIP-delta (but not cFLIP-alpha) protein was robustly expressed. After controlled cortical impact (CCI), cFLIP-alpha expression increased initially then decreased to control levels at 12 h, increasing again at 24-72 h (P<0.05). cFLIP-delta expression was decreased in brain homogenates by 12 h after CCI, then increased again at 24 to 72 h (P<0.05). cFLIP-delta immunostaining was markedly reduced in injured cortex, but not hippocampus, at 3 to 72 h after CCI. In cortex, reduced cFLIP-delta staining was found in TUNEL-positive cells, but in hippocampus TUNEL-positive cells expressed cFLIP-delta immunoreactivity. cFLIP-delta was increased in a subset of reactive astrocytes in pericontusional cortex and hippocampus at 48 to 72 h. Low levels of both cFLIP isoforms were detected in human cortical tissue with no TBI, from four patients undergoing brain surgery for epilepsy and <24 h post mortem from three patients without CNS pathologic assessment. In cortical tissue surgically removed <18 h after severe TBI (n=3), cFLIP-alpha expression was increased relative to epilepsy controls (P<0.05) but not relative to post-mortem controls. The data suggest differential spatial and temporal regulation of cFLIP-alpha and cFLIP-delta expression that may influence the magnitude of cell death and further implicate programmed mechanisms of cell death after TBI.
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Affiliation(s)
- Atticus H Hainsworth
- Neuroscience Center, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts, USA
- Pharmacology Research Group, Leicester School of Pharmacy, De Montfort University, Leicester, UK
| | - Daniela Bermpohl
- Neuroscience Center, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts, USA
| | - Tania E Webb
- Pharmacology Research Group, Leicester School of Pharmacy, De Montfort University, Leicester, UK
| | - Ribal Darwish
- Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Gary Fiskum
- Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Jianhua Qiu
- Neuroscience Center, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts, USA
| | - Deirdre McCarthy
- Neuroscience Center, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts, USA
| | - Michael A Moskowitz
- Neuroscience Center, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts, USA
- Department of Radiology, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Michael J Whalen
- Neuroscience Center, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts, USA
- Department of Radiology, Massachusetts General Hospital, Boston, Massachusetts, USA
- Department of Pediatrics, Massachusetts General Hospital, Boston, Massachusetts, USA
- Correspondence: Dr MJ Whalen, Neuroscience Center, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA. E-mail:
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125
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Abstract
Autophagy is an evolutionarily conserved mechanism for the degradation of cellular components in the cytoplasm, and serves as a cell survival mechanism in starving cells. Recent studies indicate that autophagy also functions in cell death, but the precise role of this catabolic process in dying cells is not clear. Here I discuss the possible roles for autophagy in dying cells and how understanding the relationship between autophagy, cell survival and cell death is important for health and development.
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Affiliation(s)
- Eric H Baehrecke
- Eric H. Baehrecke is at the Center for Biosystems Research, University of Maryland Biotechnology Institute, College Park, Maryland 20742, USA.
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126
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Yoshimi A, Ito M, Kojima S. Leukemic cell death induced by antithymocyte globulin. Leuk Res 2005; 29:821-7. [PMID: 15893374 DOI: 10.1016/j.leukres.2002.11.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2002] [Accepted: 11/01/2002] [Indexed: 10/25/2022]
Abstract
We studied the cytotoxic effects of antithymocyte globulin (ATG) in leukemic cells obtained from five patients with acute T lymphoblastic leukemia or precursor T lymphoblastic leukemia. ATG by itself killed leukemic cells in a dose-dependent manner. Simultaneous incubation with human AB or baby rabbit serum resulted in increased cytolysis of leukemic cells. These results suggested the presence of both direct and complement-mediated cytolysis. We also examined apoptotic cell death using Annexin-V. Cell incubation with ATG increased Annexin-V binding significantly compared with horse IgG (50.3+/-7.6% versus 95.7+/-1.8%, p = or < 0.0001). However, ATG did not induce apparent DNA fragmentation in a human T-ALL cell line. Neither anti-Fas MoAb (ZB4) nor a broad caspase inhibitor (z-VAD FMK) prevented this increase in Annexin-V binding. These results suggest that ATG induces leukemic cell death in a Fas/Fas-ligand- and caspase-independent manner.
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Affiliation(s)
- Ayami Yoshimi
- Department of Pediatrics/Developmental Pediatrics, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
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127
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Degterev A, Huang Z, Boyce M, Li Y, Jagtap P, Mizushima N, Cuny GD, Mitchison TJ, Moskowitz MA, Yuan J. Chemical inhibitor of nonapoptotic cell death with therapeutic potential for ischemic brain injury. Nat Chem Biol 2005; 1:112-9. [PMID: 16408008 DOI: 10.1038/nchembio711] [Citation(s) in RCA: 2241] [Impact Index Per Article: 117.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2005] [Accepted: 05/10/2005] [Indexed: 11/08/2022]
Abstract
The mechanism of apoptosis has been extensively characterized over the past decade, but little is known about alternative forms of regulated cell death. Although stimulation of the Fas/TNFR receptor family triggers a canonical 'extrinsic' apoptosis pathway, we demonstrated that in the absence of intracellular apoptotic signaling it is capable of activating a common nonapoptotic death pathway, which we term necroptosis. We showed that necroptosis is characterized by necrotic cell death morphology and activation of autophagy. We identified a specific and potent small-molecule inhibitor of necroptosis, necrostatin-1, which blocks a critical step in necroptosis. We demonstrated that necroptosis contributes to delayed mouse ischemic brain injury in vivo through a mechanism distinct from that of apoptosis and offers a new therapeutic target for stroke with an extended window for neuroprotection. Our study identifies a previously undescribed basic cell-death pathway with potentially broad relevance to human pathologies.
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Affiliation(s)
- Alexei Degterev
- Department of Cell Biology, Harvard Medical School, 240 Longwood Avenue, Boston, Massachusetts 02115, USA
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128
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Engels IH, Totzke G, Fischer U, Schulze-Osthoff K, Jänicke RU. Caspase-10 sensitizes breast carcinoma cells to TRAIL-induced but not tumor necrosis factor-induced apoptosis in a caspase-3-dependent manner. Mol Cell Biol 2005; 25:2808-18. [PMID: 15767684 PMCID: PMC1061657 DOI: 10.1128/mcb.25.7.2808-2818.2005] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Although signaling by death receptors involves the recruitment of common components into their death-inducing signaling complexes (DISCs), apoptosis susceptibility of various tumor cells to each individual receptor differs quite dramatically. Recently it was shown that, besides caspase-8, caspase-10 is also recruited to the DISCs, but its function in death receptor signaling remains unknown. Here we show that expression of caspase-10 sensitizes MCF-7 breast carcinoma cells to TRAIL- but not tumor necrosis factor (TNF)-induced apoptosis. This sensitization is most obvious at low TRAIL concentrations or when apoptosis is assessed at early time points. Caspase-10-mediated sensitization for TRAIL-induced apoptosis appears to be dependent on caspase-3, as expression of caspase-10 in MCF-7/casp-3 cells but not in caspase-3-deficient MCF-7 cells overcomes TRAIL resistance. Interestingly, neutralization of TRAIL receptor 2 (TRAIL-R2), but not TRAIL-R1, impaired apoptosis in a caspase-10-dependent manner, indicating that caspase-10 enhances TRAIL-R2-induced cell death. Furthermore, whereas processing of caspase-10 was delayed in TNF-treated cells, TRAIL triggered a very rapid activation of caspase-10 and -3. Therefore, we propose a model in which caspase-10 is a crucial component during TRAIL-mediated apoptosis that in addition actively requires caspase-3. This might be especially important in systems where only low TRAIL concentrations are supplied that are not sufficient for the fast recruitment of caspase-8 to the DISC.
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Affiliation(s)
- Ingo H Engels
- Institute of Molecular Medicine, University of Düsseldorf, Building 23.12, Universitätsstrasse 1, D-40225 Düsseldorf, Germany
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129
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Chipuk JE, Green DR. Do inducers of apoptosis trigger caspase-independent cell death? Nat Rev Mol Cell Biol 2005; 6:268-75. [PMID: 15714200 DOI: 10.1038/nrm1573] [Citation(s) in RCA: 248] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Apoptotic cell death is mediated by molecular pathways that culminate in the activation of a family of cysteine proteases, known as the caspases, which orchestrate the dismantling and clearance of the dying cell. However, mounting evidence indicates that a cell that has been treated with an apoptotic inducer can also initiate a suicide programme that does not rely on caspase activation. Here, we present recent findings and discuss the physiological relevance of caspase-independent cell death.
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Affiliation(s)
- Jerry E Chipuk
- Division of Cellular Immunology, La Jolla Institute for Allergy and Immunology, 10355 Science Center Drive, San Diego, California 92121, USA.
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130
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Saelens X, Festjens N, Parthoens E, Vanoverberghe I, Kalai M, van Kuppeveld F, Vandenabeele P. Protein synthesis persists during necrotic cell death. ACTA ACUST UNITED AC 2005; 168:545-51. [PMID: 15699214 PMCID: PMC2171745 DOI: 10.1083/jcb.200407162] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Cell death is an intrinsic part of metazoan development and mammalian immune regulation. Whereas the molecular events orchestrating apoptosis have been characterized extensively, little is known about the biochemistry of necrotic cell death. Here, we show that, in contrast to apoptosis, the induction of necrosis does not lead to the shut down of protein synthesis. The rapid drop in protein synthesis observed in apoptosis correlates with caspase-dependent breakdown of eukaryotic translation initiation factor (eIF) 4G, activation of the double-stranded RNA-activated protein kinase PKR, and phosphorylation of its substrate eIF2-α. In necrosis induced by tumor necrosis factor, double-stranded RNA, or viral infection, de novo protein synthesis persists and 28S ribosomal RNA fragmentation, eIF2-α phosphorylation, and proteolytic activation of PKR are absent. Collectively, these results show that, in contrast to apoptotic cells, necrotic dying cells retain the opportunity to synthesize proteins.
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Affiliation(s)
- Xavier Saelens
- Molecular Signalling and Cell Death Unit, Department for Molecular Biomedical Research, Flanders Interuniversity Institute for Biotechnology (VIB) and Ghent University, B9052 Ghent, Belgium
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131
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Bras M, Queenan B, Susin SA. Programmed cell death via mitochondria: Different modes of dying. BIOCHEMISTRY (MOSCOW) 2005; 70:231-9. [PMID: 15807663 DOI: 10.1007/s10541-005-0105-4] [Citation(s) in RCA: 195] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Programmed cell death (PCD) is a major component of normal development, preservation of tissue homeostasis, and elimination of damaged cells. Many studies have subdivided PCD into the three categories of apoptosis, autophagy, and necrosis based on criteria such as morphological alterations, initiating death signal, or the implication of caspases. However, these classifications fail to address the interplay between the three types of PCD. In this review, we will discuss the central role of the mitochondrion in the integration of the cell death pathways. Mitochondrial alterations such as the release of sequestered apoptogenic proteins, loss of transmembrane potential, production of reactive oxygen species (ROS), disruption of the electron transport chain, and decreases in ATP synthesis have been shown to be involved in, and possibly responsible for, the different manifestations of cell death. Thus, the mitochondria can be viewed as a central regulator of the decision between cellular survival and demise.
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Affiliation(s)
- M Bras
- Apoptose et Systeme Immunitaire, Institut Pasteur, CNRS-URA 1961, Paris 75015, France
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132
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Hans G, Wislet-Gendebien S, Lallemend F, Robe P, Rogister B, Belachew S, Nguyen L, Malgrange B, Moonen G, Rigo JM. Peripheral benzodiazepine receptor (PBR) ligand cytotoxicity unrelated to PBR expression. Biochem Pharmacol 2005; 69:819-30. [PMID: 15710359 DOI: 10.1016/j.bcp.2004.11.029] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2004] [Accepted: 11/29/2004] [Indexed: 10/25/2022]
Abstract
Some synthetic ligands of the peripheral-type benzodiazepine receptor (PBR), an 18 kDa protein of the outer mitochondrial membrane, are cytotoxic for several tumor cell lines and arise as promising chemotherapeutic candidates. However, conflicting results were reported regarding the actual effect of these drugs on cellular survival ranging from protection to toxicity. Moreover, the concentrations needed to observe such a toxicity were usually high, far above the affinity range for their receptor, hence questioning its specificity. In the present study, we have shown that micromolar concentrations of FGIN-1-27 and Ro 5-4864, two chemically unrelated PBR ligands are toxic for both PBR-expressing SK-N-BE neuroblastoma cells and PBR-deficient Jurkat lymphoma cells. We have thereby demonstrated that the cytotoxicity of these drugs is unrelated to their PBR-binding activity. Moreover, Ro 5-4864-induced cell death differed strikingly between both cell types, being apoptotic in Jurkat cells while necrotic in SK-N-BE cells. Again, this did not seem to be related to PBR expression since Ro 5-4864-induced death of PBR-transfected Jurkat cells remained apoptotic. Taken together, our results show that PBR is unlikely to mediate all the effects of these PBR ligands. They however confirm that some of these ligands are very effective cytotoxic drugs towards various cancer cells, even for reputed chemoresistant tumors such as neuroblastoma, and, surprisingly, also for PBR-lacking tumor cells.
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Affiliation(s)
- Gregory Hans
- Centre of Cellular and Molecular Neurobiology, Université de Liège, 17 Place Delcour, 4020 Liège 2, Belgium.
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133
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Kawahara A, Che YS, Hanaoka R, Takeda H, Dawid IB. Zebrafish GADD45beta genes are involved in somite segmentation. Proc Natl Acad Sci U S A 2005; 102:361-6. [PMID: 15623554 PMCID: PMC544321 DOI: 10.1073/pnas.0408726102] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Somites in vertebrates are periodic segmented structures that give rise to the vertebrae and muscles of body. Somites are generated from presomitic mesoderm (PSM), but it is not fully understood how cellular differentiation and segment formation are achieved in the anterior PSM. We report here that zebrafish gadd45beta1 and gadd45beta2 genes are periodically expressed as paired stripes adjacent to the neural tube in the anterior PSM region where presomitic cells mature. In mammals, it is known that GADD45 (growth arrest and DNA damage) family proteins play a role in cell-cycle control. We found that both knockdown and overexpression of gadd45beta genes caused somite defects with different consequences for marker gene expression. Knockdown of gadd45beta genes with antisense morpholino oligonucleotides caused a broad expansion of mesp-a in the PSM, and both cyclic expression of her1 and segmented expression of MyoD were disorganized. On the other hand, injection of gadd45beta1 or gadd45beta2 suppressed expression of mesp-a and her1 in anterior PSM and MyoD in paraxial mesoderm. These results indicate that regulated expression of gadd45beta genes in the anterior PSM is required for somite segmentation.
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Affiliation(s)
- Atsuo Kawahara
- Laboratory of Developmental Molecular Genetics, Horizontal Medical Research Organization, Kyoto University Faculty of Medicine, Yoshida, Sakyo-Ku, Kyoto 606-8501, Japan.
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134
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Li W, Simarro M, Kedersha N, Anderson P. FAST is a survival protein that senses mitochondrial stress and modulates TIA-1-regulated changes in protein expression. Mol Cell Biol 2004; 24:10718-32. [PMID: 15572676 PMCID: PMC533970 DOI: 10.1128/mcb.24.24.10718-10732.2004] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The Fas-activated serine/threonine phosphoprotein (FAST) is tethered to the outer mitochondrial membrane, where it interacts with BCL-X(L) (17). Here we show that RNA interference-mediated knockdown of endogenous FAST results in apoptosis, whereas overexpressed recombinant FAST inhibits Fas- and UV-induced apoptosis, indicating that FAST is a survival protein. The antiapoptotic effects of FAST are regulated by interactions with the translational silencer TIA-1: a FAST mutant lacking its TIA-1-binding domain does not inhibit apoptosis, and overexpressed recombinant TIA-1 inhibits the antiapoptotic effects of FAST. Because the antiapoptotic effects of FAST require ongoing protein synthesis, we hypothesized that FAST might function by preventing TIA-1-mediated silencing of mRNAs encoding inhibitors of apoptosis. Consistent with this hypothesis, FAST promotes the expression of cotransfected reporter proteins, a process that requires its TIA-1-binding domain and is inhibited by overexpressed recombinant TIA-1. More compellingly, recombinant FAST increases the expression of endogenous cIAP-1 and XIAP, but not GAPDH, in transfected HeLa cells. Because FAST is released from mitochondria in cells undergoing Fas- or UV-induced apoptosis, we propose that FAST serves as a sensor of mitochondrial stress that modulates a TIA-1-regulated posttranscriptional stress response program.
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Affiliation(s)
- Wei Li
- Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital, Smith 652, One Jimmy Fund Way, Boston, MA 02115, USA
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135
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Graham EM, Sheldon RA, Flock DL, Ferriero DM, Martin LJ, O'Riordan DP, Northington FJ. Neonatal mice lacking functional Fas death receptors are resistant to hypoxic-ischemic brain injury. Neurobiol Dis 2004; 17:89-98. [PMID: 15350969 DOI: 10.1016/j.nbd.2004.05.007] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2003] [Revised: 05/27/2004] [Accepted: 05/27/2004] [Indexed: 12/20/2022] Open
Abstract
Neonatal hypoxia-ischemia (HI) upregulates Fas death receptor expression in the brain, and alterations in expression and activity of Fas signaling intermediates occur in neonatal brain injury. B6.MRL-Tnfrsf6(lpr) mice lacking functional Fas death receptors are protected from HI brain damage in cortex, striatum, and thalamus compared to wild-type mice. Expression of Fas death receptor and active caspases increase in the cortex after HI. In wild-type mice, the hippocampus is most severely injured, and the hippocampus is the only region not protected in the B6.MRL-Tnfrsf6(lpr) mice. The selective vulnerability of the hippocampus to injury correlates with (1) lower basal expression of [Fas-associated death-domain-like IL-1beta-converting enzyme]-inhibitory protein (FLIP), (2) increased degradation of spectrin to its 145 or 150 kDa breakdown product, and (3) a higher percentage of non-apoptotic cell death following neonatal HI. We conclude that Fas signaling via both extrinsic and intrinsic caspase cascades causes brain injury following neonatal HI in a region-dependent manner. Basal levels of endogenous decoy proteins may modulate the response to Fas death receptor signaling and provide a novel approach to understanding mechanisms of neonatal brain injury.
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Affiliation(s)
- Ernest M Graham
- Department of Gyn-Ob, Division of Maternal-Fetal Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
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136
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Kalvakolanu DV. The GRIMs: a new interface between cell death regulation and interferon/retinoid induced growth suppression. Cytokine Growth Factor Rev 2004; 15:169-94. [PMID: 15110800 DOI: 10.1016/j.cytogfr.2004.01.002] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Cytokines and vitamins play a central role in controlling neoplastic cell growth. The interferon (IFN) family of cytokines regulates antiviral, anti-tumor, antimicrobial, differentiation, and immune responses in mammals. Significant advances have been made with respect to IFN-induced signal transduction pathways and antiviral responses. However, the IFN-induced anti-tumor actions are poorly defined. Although IFNs themselves inhibit tumor growth, combination of IFNs with retinoids (a class of Vitamin A related compounds) strongly potentiates the IFN-regulated anti-tumor action in a number of cell types. To define the molecular mechanisms involved in IFN/retinoid (RA)-induced apoptosis we have employed a genetic approach and identified several critical genes. In this review, I provide the current picture of IFN- RA- and IFN/RA-regulated growth suppressive pathways. In particular, I focus on a novel set of genes, the genes-associated with retinoid-interferon induced mortality (GRIM). GRIMs may be novel types of tumor suppressors, useful as biological response markers and potentially novel targets for drug development.
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Affiliation(s)
- Dhananjaya V Kalvakolanu
- Molecular and Cell Biology Graduate Program, Department of Microbiology and Immunology, Greenebaum Cancer Center, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
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137
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Abstract
Apoptosis is the best-characterized form of programmed cell death (PCD) and is of fundamental importance in tissue homeostasis. In mammalian systems, there are two major pathways that are involved in the initiation of apoptosis: the "extrinsic" death receptor pathway and the "intrinsic" mitochondrial pathway. Although these pathways act independently to initiate the death machinery in some cellular systems, in many cell types, including numerous tumor cells, there is delicate coordination and cross talk between the extrinsic and intrinsic pathways, which leads to the activation of the executioner caspase cascade. Additionally, there appears to be a fine balance between the caspase-mediated arm of death receptor signaling that engages mitochondria and the caspase-independent arm that promotes vacuole proliferation in many cells. Here, we review our current knowledge about the layers of complexity that are posed by the interactions between death receptor-induced pathways and how they influence mitochondria to regulate cellular life and death decisions.
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Affiliation(s)
- Roya Khosravi-Far
- Department of Pathology, Harvard Medical School, Beth Israel Deaconess Medical Center, 99 Brookline Ave., Boston, Massachusetts 02215, USA.
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138
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Imamura R, Konaka K, Matsumoto N, Hasegawa M, Fukui M, Mukaida N, Kinoshita T, Suda T. Fas Ligand Induces Cell-autonomous NF-κB Activation and Interleukin-8 Production by a Mechanism Distinct from That of Tumor Necrosis Factor-α. J Biol Chem 2004; 279:46415-23. [PMID: 15337758 DOI: 10.1074/jbc.m403226200] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Fas ligand (FasL) has been well characterized as a death factor. However, recent studies revealed that FasL possesses inflammatory activity. Here we found that FasL induces production of the inflammatory chemokine IL-8 without inducing apoptosis in HEK293 cells. Reporter gene assays involving wild-type and mutated IL-8 promoters and NF-kappaB- and AP-1 reporter constructs indicated that an FasL-induced NF-kappaB and AP-1 activity are required for maximal promoter activity. FasL induced NF-kappaB activation with slower kinetics than did TNF-alpha, yet this response was cell autonomous and not mediated by secondary paracrine factors. The death domain of Fas, FADD, and caspase-8 were required for NF-kappaB activation by FasL. A dominant-negative mutant of IKKgamma inhibited the FasL-induced NF-kappaB activation. However, TRADD and RIP, which are essential for the TNF-alpha-induced NF-kappaB activation, were not involved in the FasL-induced NF-kappaB activation. Moreover, CLARP/FLIP inhibited the FasL- but not the TNF-alpha-induced NF-kappaB activation. These results show that FasL induces NF-kappaB activation and IL-8 production by a novel mechanism, distinct from that of TNF-alpha. In addition, we found that mouse FADD had a dominant-negative effect on the FasL-induced NF-kappaB activation in HEK293 cells, which may indicate a species difference between human and mouse in the FasL-induced NF-kappaB activation.
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Affiliation(s)
- Ryu Imamura
- Center for the Development of Molecular Target Drugs, Kanazawa University, 13-1 Takaramachi, Kanazawa, Ishikawa 920-0934, Japan
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139
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Kosta A, Roisin-Bouffay C, Luciani MF, Otto GP, Kessin RH, Golstein P. Autophagy Gene Disruption Reveals a Non-vacuolar Cell Death Pathway in Dictyostelium. J Biol Chem 2004; 279:48404-9. [PMID: 15358773 DOI: 10.1074/jbc.m408924200] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Types of cell death include apoptosis, necrosis, and autophagic cell death. The latter can be defined as death of cells containing autophagosomes, autophagic bodies, and/or vacuoles. Are autophagy and vacuolization causes, consequences, or side effects in cell death with autophagy? Would control of autophagy suffice to control this type of cell death? We disrupted the atg1 autophagy gene in Dictyostelium discoideum, a genetically tractable model for developmental autophagic vacuolar cell death. The procedure that induced autophagy, vacuolization, and death in wild-type cells led in atg1 mutant cells to impaired autophagy and to no vacuolization, demonstrating that atg1 is required for vacuolization. Unexpectedly, however, cell death still took place, with a non-vacuolar and centrally condensed morphology. Thus, a cell death mechanism that does not require vacuolization can operate in this cell death model showing conspicuous vacuolization. The revelation of non-vacuolar cell death in this protist by autophagy gene disruption is reminiscent of caspase inhibition revealing necrotic cell death in animal cells. Thus, hidden alternative cell death pathways may be found across kingdoms and for diverse types of cell death.
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Affiliation(s)
- Artemis Kosta
- Centre d'Immunologie INSERM/CNRS/Université de la Mediterranée de Marseille-Luminy, Case 906, Avenue de Luminy, 13288 Marseille Cedex 9, France
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140
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Walsh CM, Luhrs KA, Arechiga AF. The "fuzzy logic" of the death-inducing signaling complex in lymphocytes. J Clin Immunol 2004; 23:333-53. [PMID: 14601642 DOI: 10.1023/a:1025313415487] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Receptors belonging to the tumor necrosis factor receptor family have long been thought to play an important role in the regulation of immunity. Although this family is composed of a large number of surface receptors that potentiate myriad functions in vivo, a subset is known to directly convey apoptotic signals. One such molecule belonging to this subset is CD95. Ligation of CD95 instigates the formation of a complex known as the "death-inducing signaling complex" or DISC, which is composed of molecules including FADD (Fas associated with death domain) and RIP (receptor-interacting kinase), as well as procaspases-8 and -10, and a caspase-8-like molecule that lacks proteolytic activity called c-FLIP. Although the DISC was initially thought to serve an exclusively proapoptotic role, humans and mice with defects in various components of this complex demonstrate a variety of developmental and hematopoietic defects that are not apparently due to aberrant apoptosis. These findings paint a far more complex picture of the numerous components of the DISC, and provide evidence that these complexes serve nonapoptotic functions. Herein, we summarize the experimental evidence challenging the notion that the DISC imparts an exclusively apoptotic function and provide hypotheses to account for these alternative roles. Rather than operating as a binary system, we propose that the DISCs formed around various DRs transduce signals leading to a variety of cellular fates.
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Affiliation(s)
- Craig M Walsh
- Department of Molecular Biology and Biochemistry, University of California, Irvine, California 92697-3900, USA.
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141
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Zhang L, Shimizu S, Sakamaki K, Yonehara S, Tsujimoto Y. A caspase-8-independent signaling pathway activated by Fas ligation leads to exposure of the Bak N terminus. J Biol Chem 2004; 279:33865-74. [PMID: 15159409 DOI: 10.1074/jbc.m403499200] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Bak is a pro-apoptotic member of the Bcl-2 family that is activated by apoptotic stimulation: its activation is characterized by conformational changes such as exposure of the N terminus and oligomerization. In death receptor-mediated apoptosis, the activation of Bak depends on activation of caspase-8. However, we found that exposure of the N terminus of Bak (but not oligomerization) can occur in the absence of active caspase-8. Although exposure of the N terminus of Bak without oligomerization is not sufficient to release cytochrome c from the mitochondria and commit cells to apoptosis, this change sensitizes the mitochondria to apoptotic signals (including Bid) and thus sensitizes cells to apoptotic death. Fas-induced, caspase-8-independent exposure of the N terminus of Bak is blocked by staurosporine, a pan protein kinase inhibitor. These results suggest that Fas stimulation not only activates caspase-8, but also a distinct signaling pathway involving protein kinase(s) to induce exposure of the N terminus of Bak.
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Affiliation(s)
- Lilin Zhang
- Laboratory of Molecular Genetics, Department of Post-Genomics and Diseases, Osaka University Medical School and Solution-Oriented Research for Science and Technology, Japan Science and Technology Corp., 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan
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142
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Abstract
Programmed cell death is a major component of both normal development and disease. The roles of cell death during either embryogenesis or pathogenesis, the signals that modulate this event, and the mechanisms of cell demise are the major subjects that drive research in this field. Increasing evidence obtained both in vitro and in vivo supports the hypothesis that a variety of cell death programs may be triggered in distinct circumstances. Contrary to the view that caspase-mediated apoptosis represents the standard programmed cell death, recent studies indicate that an apoptotic morphology can be produced independent of caspases, that autophagic execution pathways of cell death may be engaged without either the involvement of caspases or morphological signs of apoptosis, and that even the necrotic morphology of cell death may be consistently produced in some cases, including certain plants. Alternative cell death programs may imply novel therapeutic targets, with important consequences for attempts to treat diseases associated with disregulated programmed cell death.
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143
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Bárcia RN, Della Valle NS, McLeod JD. P-glycoprotein decreases with T cell maturation but is not responsible for resistance to CD95-induced apoptosis. Immunobiology 2004; 207:295-304. [PMID: 12952352 DOI: 10.1078/0171-2985-00240] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
P-glycoprotein (Pgp) is a membrane transporter responsible for resistance to chemotherapy in cancer cells. Its presence in T cells is very well documented, but its function in the immune system is still poorly understood. Recent findings suggest that Pgp may be involved in regulating programmed cell death by inhibiting caspase 8 and caspase 3. Utilising antigenically-activated T cells and the physiologically relevant apoptotic ligand, membrane CD95-L, we have previously reported that while T cells are generally resistant to CD95-induced death at early stages of activation, their susceptibility to apoptosis increases with successive activation and clonal expansion. In this study we investigated whether changes in apoptotic susceptibility were related to T cell Pgp function. Results showed that Pgp expression and function in T cells decreases with maturation, with CD8 cells having the highest Pgp function. However, although Pgp function inversely correlated with caspase 3 activity, no difference was observed between apoptotic susceptible CD25- cells and resistant CD25+ cells. In addition sorting of cells with high and low Pgp function showed no correlation with apoptotic capability. Therefore, whilst Pgp modulates caspase activity, it is not responsible for resistance to apoptosis of early activated T cells nor the increased susceptibility observed at the later stages of maturation in antigenically activated cells.
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Affiliation(s)
- Rita N Bárcia
- Centre for Research in Biomedicine, University of the West of England, Coldharbour Lane, Bristol, BS16 1QY, UK
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144
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Song R, Mahidhara RS, Zhou Z, Hoffman RA, Seol DW, Flavell RA, Billiar TR, Otterbein LE, Choi AMK. Carbon monoxide inhibits T lymphocyte proliferation via caspase-dependent pathway. THE JOURNAL OF IMMUNOLOGY 2004; 172:1220-6. [PMID: 14707100 DOI: 10.4049/jimmunol.172.2.1220] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
T lymphocyte activation and proliferation is involved in many pathological processes. We have recently shown that carbon monoxide (CO), an enzymatic product of heme oxygenase-1 (HO-1), confers potent antiproliferative effects in airway and vascular smooth muscle cells. The purpose of this study was to determine whether CO can inhibit T lymphocyte proliferation and then to determine the mechanism by which CO can modulate T lymphocyte proliferation. In the presence of 250 parts per million CO, CD3-activated T lymphocyte proliferation was, remarkably, inhibited by 80% when compared with controls. We observed that the antiproliferative effect of CO in T lymphocytes was independent of the mitogen-activated protein kinase or cGMP signaling pathways, unlike what we demonstrated previously in smooth muscle cells. We demonstrate that CO inhibited caspase-3 and caspase-8 expression and activity, and caspase inhibition with benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone (Z-VAD-FMK pan-caspase inhibitor) blocked T lymphocyte proliferation. Furthermore, in caspase-8-deficient lymphocytes, the antiproliferative effect of CO was markedly attenuated, further supporting the involvement of caspase-8 in the antiproliferative effects of CO. CO also increased the protein level of p21(Cip1), and CO-mediated inhibition of caspase activity is partially regulated by p21(Cip1). Taken together, these data suggest that CO confers potent antiproliferative effects in CD3-activated T lymphocytes and that these antiproliferative effects in T lymphocytes are mediated by p21(Cip1)-dependent caspase activity, in particular caspase-8, independent of cGMP and mitogen-activated protein kinase signaling pathways.
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Affiliation(s)
- Ruiping Song
- Division of Pulmonary, Allergy and Critical Care Medicine, University of Pittsburgh School of Medicine, 3459 5th Avenue, Pittsburgh, PA 15213, USA
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145
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Filippova M, Parkhurst L, Duerksen-Hughes PJ. The human papillomavirus 16 E6 protein binds to Fas-associated death domain and protects cells from Fas-triggered apoptosis. J Biol Chem 2004; 279:25729-44. [PMID: 15073179 DOI: 10.1074/jbc.m401172200] [Citation(s) in RCA: 116] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
High risk strains of human papillomavirus (HPV), such as HPV 16, cause human cervical carcinoma. The E6 protein of HPV 16 mediates the rapid degradation of the tumor suppressor p53, although this is not the only function of E6 and cannot completely explain its transforming potential. Previous work in our laboratory has demonstrated that E6 can protect cells from tumor necrosis factor-induced apoptosis by binding to the C-terminal end of tumor necrosis factor R1, thus blocking apoptotic signal transduction. In this study, E6 was shown to also protect cells from apoptosis induced via the Fas pathway. Furthermore, use of an inducible E6 expression system demonstrated that this protection is dose-dependent, with higher levels of E6 leading to greater protection. Although E6 suppresses activation of both caspase 3 and caspase 8, it does not affect apoptotic signaling through the mitochondrial pathway. Mammalian two-hybrid and in vitro pull-down assays were then used to demonstrate that E6 binds directly to the death effector domain of Fas-associated death domain (FADD), with deletion and site-directed mutants enabling the localization of the E6-binding site to the N-terminal end of the FADD death effector domain. E6 is produced in two forms as follows: a full-length version of approximately 16 kDa and a smaller version of about half that size corresponding to the N-terminal half of the full-length protein. Pull-down and functional assays demonstrated that the full-length version, but not the small version of E6, was able to bind to FADD and to protect cells from Fas-induced apoptosis. In addition, binding to E6 leads to degradation of FADD, with the loss of cellular FADD proportional to the amount of E6 expressed. These results support a model in which E6-mediated degradation of FADD prevents transmission of apoptotic signals via the Fas pathway.
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Affiliation(s)
- Maria Filippova
- Department of Biochemistry and Microbiology, Center for Molecular Biology and Gene Therapy, Loma Linda University School of Medicine, Loma Linda, California 92354, USA
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146
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Naito M, Hashimoto C, Masui S, Tsuruo T. Caspase-independent necrotic cell death induced by a radiosensitizer, 8-nitrocaffeine. Cancer Sci 2004; 95:361-6. [PMID: 15072596 PMCID: PMC11158938 DOI: 10.1111/j.1349-7006.2004.tb03216.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2003] [Revised: 02/09/2004] [Accepted: 02/10/2004] [Indexed: 11/26/2022] Open
Abstract
Molecular mechanisms of apoptosis have been extensively studied, but little is known about non-apoptotic cell death. To study the mechanism of non-apoptotic cell death, we searched for non-apoptotic cell death inducers for U937 cells, which are highly sensitive to apoptosis induction by various stimuli. We found that 8-nitrocaffeine and its analog, which are candidate radiosensitizers for cancer therapy, induced exclusively caspase-independent necrotic cell death in cell lines such as U937, HL-60, K562 and Jurkat. The 8-nitrocaffeine-induced necrotic cell death was mediated by reactive oxygen species (ROS) because (i) ROS were produced in the 8-nitrocaffeine-treated cells, (ii) ROS scavengers inhibited the caspase-independent necrotic cell death induced by 8-nitrocaffeine, and (iii) the necrotic cell death was completely suppressed in hypoxic cells. Cells selected for resistance to nitrocaffeine showed cross resistance to CH-11, an anti-Fas antibody, suggesting that the necrotic process plays an important role in Fas-mediated cell death in this cell line. Since cancer cells are often derived from a selected population of cells resistant to apoptosis, inducers of necrotic cell death could be beneficial to kill cancer cells that have acquired resistance to apoptosis-induction therapy.
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Affiliation(s)
- Mikihiko Naito
- Institute of Molecular and Cellular Biosciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan.
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147
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Vanden Berghe T, van Loo G, Saelens X, Van Gurp M, Brouckaert G, Kalai M, Declercq W, Vandenabeele P. Differential Signaling to Apoptotic and Necrotic Cell Death by Fas-associated Death Domain Protein FADD. J Biol Chem 2004; 279:7925-33. [PMID: 14668343 DOI: 10.1074/jbc.m307807200] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Two general pathways for cell death have been defined, apoptosis and necrosis. Previous studies in Jurkat cells have demonstrated that the Fas-associated death domain (FADD) is required for Fas-mediated signaling to apoptosis and necrosis. Here we developed L929rTA cell lines that allow Tet-on inducible expression and FK506-binding protein (FKBP)-mediated dimerization of FADD, FADD-death effector domain (FADD-DED), or FADD-death domain (FADD-DD). We show that expression and dimerization of FADD leads to necrosis. However, pretreatment of the cells with the Hsp90 inhibitor geldanamycin, which leads to proteasome-mediated degradation of receptor interacting protein 1 (RIP1), reverts FKBP-FADD-induced necrosis to apoptosis. Expression and dimerization of FADD-DD mediates necrotic cell death. We found that FADD-DD is able to bind RIP1, another protein necessary for Fas-mediated necrosis. Expression and dimerization of FADD-DED initiates apoptosis. Remarkably, in the presence of caspase inhibitors, FADD-DED mediates necrotic cell death. Coimmunoprecipitation studies revealed that FADD-DED in the absence procaspase-8 C/A is also capable of recruiting RIP1. However, when procaspase-8 C/A and RIP1 are expressed simultaneously, FADD-DED preferentially recruits procaspase-8 C/A.
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Affiliation(s)
- Tom Vanden Berghe
- Molecular Signalling and Cell Death Unit, Department of Molecular Biomedical Research, the Flanders Interuniversity Institute for Biotechnology (VIB) and Gent University, Technologiepark 927, B-9052 Zwijnaarde, Belgium
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148
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Arnoult D, Petit F, Lelièvre JD, Lelièvie JD, Lecossier D, Hance A, Monceaux V, Hurtrel B, Huntrel B, Ho Tsong Fang R, Ameisen JC, Estaquier J. Caspase-dependent and -independent T-cell death pathways in pathogenic simian immunodeficiency virus infection: relationship to disease progression. Cell Death Differ 2004; 10:1240-52. [PMID: 14576776 DOI: 10.1038/sj.cdd.4401289] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Studies of human immunodeficiency virus (HIV) and nonhuman primate models of pathogenic and nonpathogenic simian immunodeficiency virus (SIV) infections have suggested that enhanced ex vivo CD4 T-cell death is a feature of pathogenic infection in vivo. However, the relative contributions of the extrinsic and intrinsic pathways to programmed T-cell death in SIV infection have not been studied. We report here that the spontaneous death rate of CD4+ T cells from pathogenic SIVmac251-infected rhesus macaques ex vivo is correlated with CD4 T-cell depletion and plasma viral load in vivo. CD4+ T cells from SIVmac251-infected macaques showed upregulation of the death ligand (CD95L) and of the proapoptotic proteins Bim and Bak, but not of Bax. Both CD4+ and CD8+ T cells from SIVmac251-infected macaques underwent caspase-dependent death following CD95 ligation. The spontaneous death of CD4+ and CD8+ T cells was not prevented by a decoy CD95 receptor or by a broad-spectrum caspase inhibitor (zVAD-fmk), suggesting that this form of cell death is independent of CD95/CD95L interaction and caspase activation. IL-2 and IL-15 prevented the spontaneous death of CD4+ and CD8+ T cells, whereas IL-10 prevented only CD8 T-cell death and IL-7 had no effect on T-cell death. Our results indicate that caspase-dependent and caspase-independent pathways are involved in the death of T cells in pathogenic SIVmac251-infected primates.
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Affiliation(s)
- D Arnoult
- INSERM EMI-U 9922, Faculté Bichat-Claude Bernard, Paris, France
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149
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Abstract
Apoptosis is defined on the basis of morphological changes like nuclear fragmentation and chromatin condensation, which are dependent on caspases. Many forms of caspase-independent cell death have been reported, but the mechanisms are still poorly understood. We found that hypoxic cell death was independent of caspases and was associated with significant nuclear shrinkage. Neither Bcl-2 nor Apaf-1 deficiency prevented hypoxic nuclear shrinkage. To understand the molecular mechanism of the nuclear shrinkage, we developed an in vitro system using permeabilized cells, which allowed us to purify a novel member of the phospholipase A2 (PLA2) family that induced nuclear shrinkage. Purified PLA2 induced nuclear shrinkage in our permeabilized cell system. PLA2 inhibitors prevented hypoxic nuclear shrinkage in cells and cell death. Hypoxia caused elevation of PLA2 activity and translocation of intracellular PLA2s to the nucleus. Knockdown of the Ca2+-independent PLA2 delayed nuclear shrinkage and cell death. These results indicate that Ca2+-independent PLA2 is crucial for a caspase-independent cell death signaling pathway leading to nuclear shrinkage.
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Affiliation(s)
- Koei Shinzawa
- Laboratory of Molecular Genetics, Department of Post-Genomics and Diseases, Osaka University Medical School, Yamadaoka, Suita, Osaka 565-0871, Japan
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150
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Okada M, Adachi S, Imai T, Watanabe KI, Toyokuni SY, Ueno M, Zervos AS, Kroemer G, Nakahata T. A novel mechanism for imatinib mesylate-induced cell death of BCR-ABL-positive human leukemic cells: caspase-independent, necrosis-like programmed cell death mediated by serine protease activity. Blood 2003; 103:2299-307. [PMID: 14645012 DOI: 10.1182/blood-2003-05-1605] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Caspase-independent programmed cell death can exhibit either an apoptosis-like or a necrosis-like morphology. The ABL kinase inhibitor, imatinib mesylate, has been reported to induce apoptosis of BCR-ABL-positive cells in a caspase-dependent fashion. We investigated whether caspases alone were the mediators of imatinib mesylate-induced cell death. In contrast to previous reports, we found that a broad caspase inhibitor, zVAD-fmk, failed to prevent the death of imatinib mesylate-treated BCR-ABL-positive human leukemic cells. Moreover, zVAD-fmk-preincubated, imatinib mesylate-treated cells exhibited a necrosis-like morphology characterized by cellular pyknosis, cytoplasmic vacuolization, and the absence of nuclear signs of apoptosis. These cells manifested a loss of the mitochondrial transmembrane potential, indicating the mitochondrial involvement in this caspase-independent necrosis. We excluded the participation of several mitochondrial factors possibly involved in caspase-independent cell death such as apoptosis-inducing factor, endonuclease G, and reactive oxygen species. However, we observed the mitochondrial release of the serine protease Omi/HtrA2 into the cytosol of the cells treated with imatinib mesylate or zVAD-fmk plus imatinib mesylate. Furthermore, serine protease inhibitors prevented the caspase-independent necrosis. Taken together, our results suggest that imatinib mesylate induces a caspase-independent, necrosis-like programmed cell death mediated by the serine protease activity of Omi/HtrA2.
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Affiliation(s)
- Masayuki Okada
- Department of Pediatrics, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan
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