201
|
Jan Y, Matter M, Pai JT, Chen YL, Pilch J, Komatsu M, Ong E, Fukuda M, Ruoslahti E. A mitochondrial protein, Bit1, mediates apoptosis regulated by integrins and Groucho/TLE corepressors. Cell 2004; 116:751-62. [PMID: 15006356 DOI: 10.1016/s0092-8674(04)00204-1] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2002] [Revised: 12/24/2003] [Accepted: 01/14/2004] [Indexed: 10/26/2022]
Abstract
A delicate balance of signals regulates cell survival. One set of these signals is derived from integrin-mediated cell adhesion to the extracellular matrix (ECM). Loss of cell attachment to the ECM causes apoptosis, a process known as anoikis. In searching for proteins involved in cell adhesion-dependent regulation of anoikis, we identified Bit1, a mitochondrial protein that is released into the cytoplasm during apoptosis. Cytoplasmic Bit1 forms a complex with AES, a small Groucho/transducin-like enhancer of split (TLE) protein, and induces cell death with characteristics of caspase-independent apoptosis. Cell attachment to fibronectin counteracts the apoptotic effect of Bit1 and AES. Increasing Bit1 expression enhances anoikis, while suppressing the expression reduces it. Thus, we have elucidated an integrin-controlled pathway that is, at least in part, responsible for the cell survival effects of cell-ECM interactions.
Collapse
Affiliation(s)
- Yiwen Jan
- Cancer Research Center, The Burnham Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
202
|
Lu ZG, Zhang CM, Zhai ZH. LDFF, the large molecular weight DNA fragmentation factor, is responsible for the large molecular weight DNA degradation during apoptosis in Xenopus egg extracts. Cell Res 2004; 14:134-40. [PMID: 15115614 DOI: 10.1038/sj.cr.7290212] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
DNA degradation is a biochemical hallmark in apoptosis. It has been demonstrated in many cell types that there are two stages of DNA fragmentation during the apoptotic execution. In the early stage, chromatin DNA is cut into large molecular weight DNA fragments, although the responsible nuclease(s) has not been recognized. In the late stage, the chromatin DNA is cleaved further into short oligonucleosomal fragments by a well-characterized nuclease in apoptosis, the caspase-activated DNase (CAD/DFF40). In this study, we demonstrate that large molecular weight DNA fragmentation also occurs in Xenopus egg extracts in apoptosis. We show that the large molecular weight DNA fragmentation factor (LDFF) is not the Xenopus CAD homolog XCAD. LDFF is activated by caspase-3. The large molecular weight DNA fragmentation activity of LDFF is Mg2+-dependent and Ca2+-independent, can occur in both acidic and neutral pH conditions and can tolerate 45 degrees C treatment. These results indicate that LDFF in Xenopus egg extracts might be a new DNase (or DNases) responsible for the large DNA fragmentation.
Collapse
Affiliation(s)
- Zhi Gang Lu
- Department of Cell Biology and Genetics, College of Life Sciences, Peking University, Beijing 100871, China
| | | | | |
Collapse
|
203
|
Yu SW, Wang H, Dawson TM, Dawson VL. Poly(ADP-ribose) polymerase-1 and apoptosis inducing factor in neurotoxicity. Neurobiol Dis 2004; 14:303-17. [PMID: 14678748 DOI: 10.1016/j.nbd.2003.08.008] [Citation(s) in RCA: 150] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
Poly(ADP-ribose) polymerase-1 (PARP-1) is the guardian of the genome acting as a sentinel for genomic damage. However, PARP-1 is also mediator of cell death after ischemia-reperfusion injury, glutamate excitotoxicity, and various inflammatory processes. The biochemistry underlying PARP-1-mediated cell death has remained elusive, although NAD(+) consumption and energy failure have been thought to be one of the possible molecular mechanisms. Recent observations link PARP-1 activation with translocation of apoptosis-inducing factor (AIF) to the nucleus and indicate that AIF is an essential downstream effector of PARP-1-mediated cell death. PARP-1 activation signals AIF release from the mitochondria, resulting in a novel, caspase-independent pathway of programmed cell death. These recent findings suggest that AIF maybe a target for development of future therapeutic treatment for many neurological disorders involving excitotoxicity.
Collapse
Affiliation(s)
- Seong-Woon Yu
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | | | | | | |
Collapse
|
204
|
Donovan M, Cotter TG. Control of mitochondrial integrity by Bcl-2 family members and caspase-independent cell death. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2004; 1644:133-47. [PMID: 14996498 DOI: 10.1016/j.bbamcr.2003.08.011] [Citation(s) in RCA: 162] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2003] [Accepted: 08/18/2003] [Indexed: 01/13/2023]
Abstract
Programmed cell death (PCD) is essential for normal development and maintenance of tissue homeostasis in multicellular organisms. While it is now evident that PCD can take many different forms, apoptosis is probably the most well-defined cell death programme. The characteristic morphological and biochemical features associated with this highly regulated form of cell death have until recently been exclusively attributed to the caspase family of cysteine proteases. As a result, many investigators affiliate apoptosis with its pivotal execution system, i.e. caspase activation. However, it is becoming increasingly clear that PCD or apoptosis can also proceed in a caspase-independent manner and maintain key characteristics of apoptosis. Mitochondrial integrity is central to both caspase-dependent and-independent cell death. The release of pro-apoptotic factors from the mitochondrial intermembrane space is a key event in a cell's commitment to die and is under the tight regulation of the Bcl-2 family. However, the underlying mechanisms governing the efflux of these pro-death molecules are largely unknown. This review will focus on the regulation of mitochondrial integrity by Bcl-2 family members with particular attention to the controlled release of factors involved in caspase-independent cell death.
Collapse
Affiliation(s)
- Maryanne Donovan
- Cell Development and Disease, Biochemistry Department, Biosciences Institute, National University of Ireland, Cork, Ireland
| | | |
Collapse
|
205
|
Anderson CD, Belous A, Pierce J, Nicoud IB, Knox C, Wakata A, Pinson CW, Chari RS. Mitochondrial calcium uptake regulates cold preservation-induced Bax translocation and early reperfusion apoptosis. Am J Transplant 2004; 4:352-62. [PMID: 14961987 DOI: 10.1111/j.1600-6143.2004.00357.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Mitochondrial calcium (mCa + 2) overload occurs during cold preservation and is an integral part of mitochondrial-dependent apoptotic pathways. We investigated the role of mCa + 2 overload in cell death following hypothermic storage using HepG2 cells stored in normoxic-hypothermic (4 degrees C) or hypoxic (< 0.1% O2)-hypothermic Belzer storage solution. Cells were stored for 6 h, with or without 10 microM ruthenium red (mCa + 2 uniporter inhibitor) followed by rewarming in oxygenated media at 37 degrees C. Cytoplasmic cytochrome c levels were studied by Western analysis and by fluorescent microscopy after transfection of cytochrome c-GFP expression plasmid. Immunofluorescence determined the intracellular, spatio-temporal distribution of Bax, and TUNEL staining was used to evaluate cell death after 180 min of rewarming. Caspase activation was evaluated using Western analysis and a caspase 3 activity assay. Bax translocation, cytochrome c release, and early rewarming cell death occurred following hypothermic storage and were exacerbated by hypoxia. Caspase 3 activation did not occur following hypothermic storage. Blockade of mCa + 2 uptake prevented Bax translocation, cytochrome c release, and early rewarming cell death. These studies demonstrate that mCa + 2 uptake during hypothermic storage, both hypoxic and normoxic, contributes to early rewarming apoptosis by triggering Bax translocation to mitochondria and cytochrome c release.
Collapse
Affiliation(s)
- Christopher D Anderson
- Division of Hepatobiliary Surgery and Liver Transplantation, Department of Surgery, Vanderbilt University Medical Center, Nashville, TN, USA
| | | | | | | | | | | | | | | |
Collapse
|
206
|
Lambert C, Apel K, Biesalski HK, Frank J. 2-methoxyestradiol induces caspase-independent, mitochondria-centered apoptosis in DS-sarcoma cells. Int J Cancer 2004; 108:493-501. [PMID: 14696112 DOI: 10.1002/ijc.11579] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The anti-cancer potential of the natural estrogen metabolite 2-methoxyestradiol is associated with microtubuli interaction, anti-angiogenetic effects and inhibition of superoxide dismutase leading to apoptosis. The effectors of apoptotic signaling through 2-methoxyestradiol, however, are cell type-dependent. We investigated the effect of 2-methoxyestradiol on several events associated with apoptosis in rat DS-sarcoma cells. Translocation of the pro-apoptotic protein Bax to mitochondria was identified as an initial apoptotic event that was accompanied by a decrease in mitochondrial transmembrane potential and the formation of reactive oxygen species (ROS) followed by mitochondrial release of apoptosis inducing factor and endonuclease G. In addition, 2-methoxyestradiol treatment caused upregulation of death receptor ligands FasL and TNFalpha and induced caspase-8 activation. The pan caspase inhibitor Z-VAD-FMK did not suppress apoptotic cell death, however, indicating that the major pro-apoptotic effect of 2-methoxyestradiol is mediated by a caspase-independent mechanism. Furthermore, ROS do not seem to play a pivotal role in the toxic/apoptotic effect of 2-methoxyestradiol in DS-sarcoma cells because supplementation with various antioxidants provided only limit protection. Colony formation was not affected by antioxidants. Therefore, in DS-sarcoma cells, the breakdown of mitochondrial integrity with the subsequent release of mitochondrial nucleases is the main factor in 2-methoxyestradiol mediated cell death.
Collapse
Affiliation(s)
- Christine Lambert
- Department of Biological Chemistry and Nutrition, University of Hohenheim, Stuttgart, Germany
| | | | | | | |
Collapse
|
207
|
Takiguchi S, Sugino N, Esato K, Karube-Harada A, Sakata A, Nakamura Y, Ishikawa H, Kato H. Differential Regulation of Apoptosis in the Corpus Luteum of Pregnancy and Newly Formed Corpus Luteum after Parturition in Rats1. Biol Reprod 2004; 70:313-8. [PMID: 14522835 DOI: 10.1095/biolreprod.103.018853] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Apoptosis contributes to luteal regression in many species. In the postpartum rat, there are two different types of corpora lutea (CL) in the ovary: CL of pregnancy (CLP) and newly formed CL (NCL). To investigate the regulation of apoptosis in the two different types of CL during luteal regression, apoptosis and caspase-3 activity were examined in the CL obtained on Days 7, 15, and 21 of pregnancy and Days 0, 1, 3, 5, 7, and 9 postpartum. Furthermore, the effect of lactation on apoptosis in the CL was examined in two groups of postpartum rats: lactating rats that nurse more than 10 pups, and nonlactating rats that nurse no pups. Apoptotic cells were detected after Day 21 of pregnancy. In the CLP, remarkable increases in the number of apoptotic cells on Days 5 and 9 postpartum were observed in nonlactating rats (P < 0.01), but not in lactating rats. Changes in caspase-3 activity in the CLP were not consistent with those in number of apoptotic cells. In the NCL, an increase in apoptosis was found only on Day 5 postpartum in nonlactating rats (P < 0.01), but not in lactating rats. Changes in caspase-3 activity in the NCL were consistent with those in number of apoptotic cells. In conclusion, apoptosis is, at least in part, involved in luteal regression after parturition, and lactation appears to inhibit apoptosis. This study also suggests the presence of a caspase-3-independent mechanism for apoptosis in CLP regression in the rat.
Collapse
Affiliation(s)
- Shuji Takiguchi
- Department of Reproductive, Pediatric, and Infectious Science, Yamaguchi University School of Medicine, Yamaguchi 755-8505, Japan
| | | | | | | | | | | | | | | |
Collapse
|
208
|
Festjens N, van Gurp M, van Loo G, Saelens X, Vandenabeele P. Bcl-2 family members as sentinels of cellular integrity and role of mitochondrial intermembrane space proteins in apoptotic cell death. Acta Haematol 2004; 111:7-27. [PMID: 14646342 DOI: 10.1159/000074483] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In addition to their function as major energy-providing organelles of the cell, mitochondria accomplish a crucial role in apoptosis. The pro-apoptotic BH3-only members of the Bcl-2 family continuously sense the cellular integrity and well-being at various subcellular levels. If these sentinels are induced, released or activated, they converge on the release of mitochondrial intermembrane space proteins such as cytochrome c, the oxidoreductase AIF, endonuclease G, Smac/DIABLO and the serine protease Omi/HtrA2. We discuss how Bcl-2 family members integrate diverse survival and death signals and act as central regulators of apoptosis. Furthermore, we describe the current knowledge on the role of mitochondrial proteins in apoptotic cell death, discuss the molecular mechanisms of their release and the apoptotic role of mitochondria from a phylogenetic and immunological point of view.
Collapse
Affiliation(s)
- Nele Festjens
- Molecular Signaling and Cell Death Unit, Department of Molecular Biomedical Research, VIB and Ghent University, Ghent, Belgium
| | | | | | | | | |
Collapse
|
209
|
Abstract
A paradox for the cancer biology field has been the revelation that oncogenes, once thought to simply provide advantages to a cancer cell, actually put it at dire risk of cell suicide. Myc is the quintessential oncogene in this respect, as in normal cells it is required for cell cycle traverse, whereas in cancers it is overexpressed and functions as the angiogenic switch. Nonetheless, Myc overexpression kills normal cells dead in their tracks. Here we review Myc-induced pathways that contribute to the apoptotic response. Molecular analysis of Myc-induced tumors has established that some of these apoptotic pathways are essential checkpoints that guard the cell from cancer, as they are selectively bypassed during tumorigenesis. The precise mechanism(s) by which Myc targets these pathways are largely unresolved, but we propose that they involve crosstalk and feedback regulatory loops between arbiters of cell death.
Collapse
Affiliation(s)
- Jonas A Nilsson
- Department of Biochemistry, St Jude Children's Research Hospital, 332 N Lauderdale, Memphis, TN 38105, USA
| | | |
Collapse
|
210
|
Yakovlev AG, Faden AI. Mechanisms of neural cell death: Implications for development of neuroprotective treatment strategies. Neurotherapeutics 2004. [DOI: 10.1007/bf03206563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
|
211
|
Zhang J, Dong M, Li L, Fan Y, Pathre P, Dong J, Lou D, Wells JM, Olivares-Villagómez D, Van Kaer L, Wang X, Xu M. Endonuclease G is required for early embryogenesis and normal apoptosis in mice. Proc Natl Acad Sci U S A 2003; 100:15782-7. [PMID: 14663139 PMCID: PMC307645 DOI: 10.1073/pnas.2636393100] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Endonuclease G (EndoG) is a nuclear-encoded mitochondrial protein reported to be important for both nuclear DNA fragmentation during apoptosis and mitochondrial DNA replication. To evaluate the in vivo function of EndoG, we have investigated the effects of EndoG deficiency in cells and mice. We found that EndoG homozygous mutant embryos die between embryonic days 2.5 and 3.5. Mitochondrial DNA copy numbers in ovulated oocytes from EndoG heterozygous mutant and wild-type mice are similar, suggesting that EndoG is involved in a cellular function unrelated to mitochondrial DNA replication. Interestingly, we found that cells from EndoG heterozygous mutant mice exhibit increased resistance to both tumor necrosis factor alpha- and staurosporine-induced cell death. Moreover, spontaneous cell death of spermatogonia in EndoG heterozygous mutant mice is significantly reduced compared with wild-type mice. DNA fragmentation is also reduced in EndoG+/- thymocytes and splenocytes compared with wild-type cells, as well as in EndoG+/- thymus in vivo compared with that of the wild-type mice, on activation of apoptosis. These findings indicate that EndoG is essential during early embryogenesis and plays a critical role in normal apoptosis and nuclear DNA fragmentation.
Collapse
Affiliation(s)
- Jianhua Zhang
- Department of Cell Biology, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
212
|
Gabriel B, Sureau F, Casselyn M, Teissié J, Petit PX. Retroactive pathway involving mitochondria in electroloaded cytochrome c-induced apoptosis. Protective properties of Bcl-2 and Bcl-XL. Exp Cell Res 2003; 289:195-210. [PMID: 14499621 DOI: 10.1016/s0014-4827(03)00255-6] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cytochrome c release is thought to play an important role in the initiation of apoptosis. The nature of the control exerted by Bcl-2 and Bcl-XL on such a pathway is not precisely known. We addressed this issue by square-wave pulse electroloading of exogenous cytochrome c into Jurkat cells. Three hours after cytochrome c loading into the cells, characteristic phenotypes of apoptosis were observed. However, a significant drop in the mitochondrial membrane potential (Deltapsim) was also observed, while cytochrome c was generally considered to act downstream from the mitochondria. Related to the Deltapsim drop, there was a release of proapoptotic proteins such as AIF and Smac from the mitochondria. This release, as well as NAD(P)H and cardiolipids oxidation, are linked to previous caspase activation. Cytochrome c-linked caspase activation also led to potassium efflux out of the cell. Overexpression of Bcl-2 and Bcl-XL or N-acetyl-DEVD-aldehyde treatment not only prevented the mitochondrial membrane potential decrease, but also protected cells from the apoptosis directly induced by cytochrome c electroloading. Bcl-2 and Bcl-XL protection is based on the inhibition of the caspase-dependent retroactive pathway affecting the mitochondrial compartment.
Collapse
Affiliation(s)
- Bruno Gabriel
- Institut de Pharmacologie et Biologie Structurale-CNRS, UMR 5089, 205, Route de Narbonne, 31077 Toulouse Cedex 04, France
| | | | | | | | | |
Collapse
|
213
|
Guimarães CA, Benchimol M, Amarante-Mendes GP, Linden R. Alternative programs of cell death in developing retinal tissue. J Biol Chem 2003; 278:41938-46. [PMID: 12917395 DOI: 10.1074/jbc.m306547200] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We examined cell death in developing retinal tissue, following inhibition of protein synthesis, which kills undifferentiated post-mitotic cells. Ultrastructural features were found of both apoptosis and autophagy. Only approximately half of the degenerating cells were either terminal dUTP nick-end labeling (TUNEL)-positive or reacted with antibodies specific for activated caspases-3 or -9. Bongkrekic acid completely inhibited any appearance of cell death, whereas inhibitors of autophagy, caspases-9 or -3, prevented only TUNEL-positive cell death. Interestingly, inhibition of caspase-6 blocked TUNEL-negative cell death. Simultaneous inhibition of caspases-9 and -6 prevented cell death almost completely, but degeneration dependent on autophagy/caspase-9 still occurred under inhibition of both caspases-3 and -6. Thus, inhibition of protein synthesis induces in the developing retina various post-translational, mitochondria-dependent pathways of cell death. Autophagy precedes sequential activation of caspases-9 and -3, and DNA fragmentation, whereas, in parallel, caspase-6 leads to a TUNEL-negative form of cell death. Additional mechanisms of cell death may be engaged upon selective caspase inhibition.
Collapse
Affiliation(s)
- Cinthya A Guimarães
- Instituto de Biofísica, Universidade Federal do Rio de Janeiro, CCS bloco G, Cidade Universitária, 21949-900 Rio de Janeiro, Brazil
| | | | | | | |
Collapse
|
214
|
Colell A, García-Ruiz C, Lluis JM, Coll O, Mari M, Fernández-Checa JC. Cholesterol impairs the adenine nucleotide translocator-mediated mitochondrial permeability transition through altered membrane fluidity. J Biol Chem 2003; 278:33928-35. [PMID: 12821666 DOI: 10.1074/jbc.m210943200] [Citation(s) in RCA: 108] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Mitochondrial permeability transition (MPT) has been proposed to play a key role in cell death. Downstream MPT events include the release of apoptogenic factors that sets in motion the mitochondrial apoptosome leading to caspase activation. The current work examined the regulation of MPT by membrane fluidity modulated upon cholesterol enrichment. Mitochondria enriched in cholesterol displayed increased microviscosity resulting in impaired MPT induced by atractyloside, a c-conformation stabilizing ligand of the adenine nucleotide translocator (ANT). This effect was dependent on the dose of cholesterol loaded and reversed upon the fluidization of mitochondria by the fatty acid derivative A2C. Mitoplasts derived from cholesterol-enriched mitochondria responded to atractyloside in a similar fashion as intact mitochondria, indicating that a significant amount of cholesterol is still found in the inner membrane. The effects of cholesterol on MPT induced by atractyloside were mirrored by the release of intermembrane proteins, cytochrome c, Smac/Diablo, and apoptosis inducing factor. However, cholesterol loading did not affect the uptake rate of adenine nucleotide hence dissociating the function of ANT as a MPT-mediated protein from its adenine nucleotide exchange function. Thus, these findings indicate that the ability of atractyloside to induce MPT via ANT requires an appropriate membrane fluidity range.
Collapse
Affiliation(s)
- Anna Colell
- Liver Unit, Institut de Malalties Digestives, Hospital Clínic y Provincial, Instituto Investigaciones Biomédicas August Pi Suñer, Barcelona, Spain
| | | | | | | | | | | |
Collapse
|
215
|
Abstract
Apoptosis is the mode of cell death in retinitis pigmentosa, a group of retinal degenerative disorders primarily affecting rod photoreceptors. Although caspases have been demonstrated to play a central role in many incidences of apoptosis, accumulating evidence suggests that they may not be required for all forms of apoptotic cell death. The present study examined the mechanism of cell death in two in vivo models of photoreceptor apoptosis: the retinal degeneration (rd) mouse, a naturally occurring mutant model, and N-methyl-N-nitrosourea-induced retinal degeneration. Specifically, we examined the activation status of caspase-9, -8, -7, -3, and -2 and determined the caspase requirements for cytochrome c release, DNA fragmentation, and apoptosis-associated proteolysis of specific caspase substrates. We show that apoptosis in both in vivo models is independent of caspase-9, -8, -7, -3, and -2 activation. DNA fragmentation occurs in the absence of caspase-mediated ICAD (inhibitor of caspase-activated DNase) proteolysis, suggesting that an alternative endonuclease is responsible for DNA cleavage in these models. Importantly, we show that apoptosome activation is prevented because of an absence of mitochondrial cytochrome c release. Experiments performed using a cell-free system indicate that cytochrome c-dependent proteolysis and activation of caspase-9 can be restored in a neonatal cell-free system. However, we found that cytochrome c-dependent proteolysis and activation of caspase-9 could not be restored in an adult cell-free system because of an age-related decrease in the expression of Apaf-1 in the normal developing mouse retina. In the rd mouse, however, this age-related downregulation of apoptotic proteins was not observed, highlighting a critical feature of this model and the prevention of cytochrome c release as an apical event in caspase-independent apoptosis in this system.
Collapse
|
216
|
Atlante A, de Bari L, Bobba A, Marra E, Calissano P, Passarella S. Cytochrome c, released from cerebellar granule cells undergoing apoptosis or excytotoxic death, can generate protonmotive force and drive ATP synthesis in isolated mitochondria. J Neurochem 2003; 86:591-604. [PMID: 12859673 DOI: 10.1046/j.1471-4159.2003.01863.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In rat cerebellar granule cells, cytochrome c release takes place during glutamate toxicity and apoptosis due to deprivation of depolarising levels of potassium. We show that, as in necrosis, the released cytochrome c present in the cytosolic fraction obtained from cerebellar granule cells undergoing apoptosis can operate as a reactive oxygen species (ROS) scavenger and as a respiratory substrate. The capability of the cytosolic fraction containing cytochrome c, obtained from cerebellar granule cells undergoing either necrosis or apoptosis, to energise coupled mitochondria isolated by the same cells is also investigated. We show that, in both cases, the cytosolic fraction containing cytochrome c, added to mitochondria, can cause proton ejection, and membrane potential generation and can drive ATP synthesis and export in the extramitochondrial phase, as photometrically measured via the ATP detecting system. Cytochrome c, separated immunologically from the cytosolic fraction of apoptotic cells when added to mitochondria, is found to cause proton ejection to generate membrane potential and to drive ATP synthesis and export in a manner not sensitive to the further addition of the cytosolic fraction depleted of cytochrome c, which failed to do this. In the light of these findings we propose that in apoptosis the released cytochrome c can contribute to provide ATP required for the cell programmed death to occur.
Collapse
Affiliation(s)
- Anna Atlante
- Istituto di Biomembrane e Bioenergetica, CNR, Via G. Amendola, Bari, Italy.
| | | | | | | | | | | |
Collapse
|
217
|
Abstract
Discovery of the B cell lymphoma gene 2 (Bcl-2 gene) led to the concept that development of cancers required the simultaneous acquisition, not only of deregulated cell division, but also of resistance to programmed cell death or apoptosis. Apoptosis is arguably the common pathway to cell death resulting from a range of therapeutic initiatives, so that understanding the basis for the resistance of cancer cells to apoptosis may hold the key to development of new treatment initiatives. Much has already been learnt about the apoptotic pathways in cancer cells and proteins regulating these pathways. In most cells, apoptosis is dependent on the mitochondrial dependent pathway. This pathway is regulated by pro- and anti-apoptotic members of the Bcl-2 family, and manipulation of these proteins offers scope for a number of treatment initiatives. Effector caspases activated by the mitochondrial pathway or from death receptor signaling are under the control of the inhibitor of apoptosis protein (IAP) family. Certain proteins from mitochondrial can, however, competitively inhibit their binding to effector caspases. Information about the structure of these proteins has led to initiatives to develop therapeutic agents to block the IAP family. In addition to development of selective agents based on these two (Bcl-2 and IAP) protein families, much has been learnt about signal pathways that may regulate their activity. These in turn might provide additional approaches based on selective regulators of the signal pathways.
Collapse
Affiliation(s)
- Peter Hersey
- Oncology and Immunology Unit, Newcastle Mater Misericordiae Hospital, David Maddison Clinical Sciences Building, Newcastle, New South Wales, Australia.
| | | |
Collapse
|
218
|
Hughes DE, Stolz DB, Yu S, Tan Y, Reddy JK, Watkins SC, Diehl AM, Costa RH. Elevated hepatocyte levels of the Forkhead box A2 (HNF-3beta) transcription factor cause postnatal steatosis and mitochondrial damage. Hepatology 2003; 37:1414-24. [PMID: 12774021 DOI: 10.1053/jhep.2003.50253] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The Forkhead box (Fox) transcription factor Foxa2 (HNF-3beta) and related family members Foxa1 (HNF-3alpha) and Foxa3 (HNF-3gamma) act in concert with other hepatocyte nuclear factors (HNF) to coordinately regulate liver-specific gene expression. To circumvent the hepatic functional redundancy of the Foxa proteins, we used the T-77 transgenic (TG) mouse line in which the -3-kb transthyretin (TTR) promoter functioned to increase hepatocyte expression of the Foxa2 cDNA. Adult TG mice exhibited reduced hepatic glycogen and progressive liver injury, but maintained normal serum levels of glucose, insulin, and glucagon. In this study, we further characterized the postnatal liver defect in TTR-FoxA2 TG mice. The postnatal TG mice displayed significant reduction in serum glucose levels and in hepatocyte glycogen storage without increased serum levels of ketone bodies and free fatty acid suggesting that they are not undergoing a starvation response. We show that TG liver developed a substantial transient steatosis, which reached a maximum at postnatal day 5 and is associated with increased expression of hepatic genes involved in fatty acid and triglyceride synthesis, lipid beta-oxidation, and amino acid biosynthesis. Furthermore, transmission electron microscopy analysis of postnatal TG liver revealed extensive mitochondrial membrane damage, which is likely due to reactive oxygen species generated from lipid beta-oxidation. In conclusion, our model proposes that in response to reduction in hepatocyte glycogen storage, the TTR-Foxa2 TG mice survive by maintaining sufficient serum levels of glucose through gluconeogenesis using deaminated amino acids with dicarboxylate products of peroxisomal lipid beta-oxidation shuttled through the tricarboxylic acid cycle.
Collapse
Affiliation(s)
- Douglas E Hughes
- University of Illinois at Chicago, College of Medicine, Department of Molecular Genetics, Chicago, IL 60607-7170, USA
| | | | | | | | | | | | | | | |
Collapse
|
219
|
van Gurp M, Festjens N, van Loo G, Saelens X, Vandenabeele P. Mitochondrial intermembrane proteins in cell death. Biochem Biophys Res Commun 2003; 304:487-97. [PMID: 12729583 DOI: 10.1016/s0006-291x(03)00621-1] [Citation(s) in RCA: 279] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Apoptosis is a form of programmed cell death important in the development and tissue homeostasis of multicellular organisms. Mitochondria have, next to their function in respiration, an important role in the apoptotic-signaling pathway. Malfunctioning at any level of the cell is eventually translated in the release of apoptogenic factors from the mitochondrial intermembrane space resulting in the organized demise of the cell. Some of these factors, such as AIF and endonuclease G, appear to be highly conserved during evolution. Other factors, like cytochrome c, have gained their apoptogenic function later during evolution. In this review, we focus on the role of cytochrome c, AIF, endonuclease G, Smac/DIABLO, Omi/HtrA2, Acyl-CoA-binding protein, and polypyrimidine tract-binding protein in the initiation and modulation of cell death in different model organisms. These mitochondrial factors may contribute to both caspase-dependent and caspase-independent processes in apoptotic cell death.
Collapse
Affiliation(s)
- Maria van Gurp
- Molecular Signaling and Cell Death Unit, Department of Molecular Biomedical Research, VIB and Ghent University, K.L. Ledeganckstraat 35, B-9000 Ghent, Belgium
| | | | | | | | | |
Collapse
|
220
|
Abstract
F-actin cleavage was studied in PBMC after treatment with anti-dsDNA antibodies. Significant changes in F-actin disruption detected by decrease of FITC-phalloidin staining occurred after apoptosis induction with anti-dsDNA antibodies (p < 0.006). Despite of similar F-actin disruption, the switch of phosphatidylserine (PS) to the outer leaflet of the cell membrane as detected by annexin V binding was lower after anti-dsDNA antibody than without antibody treatment (58.4 +/- 11.0% vs. 81.9 +/- 7.7%). F-actin disruption was accompanied by activation of caspase 3 within the cytoplasm (r = -0.92599; p < 8.87446 x 10-(10)) under both conditions with and without autoantibodies. These findings indicate that anti-dsDNA antibody-induced apoptosis is more marked within the cell than upon the cell surface. The diminished externalization of PS might result in a decreased phagocytosis. Thereby, the reduced clearance of apoptotic cells could induce autoantibody production possibly against epitopes which arise due to the apoptotic disruption of cells.
Collapse
Affiliation(s)
- Ingrid Böhm
- Department of Radiology, University of Bonn, Sigmund-Freud Strasse 25, 53105 Bonn, Germany.
| |
Collapse
|
221
|
Tatton WG, Chalmers-Redman R, Brown D, Tatton N. Apoptosis in Parkinson's disease: signals for neuronal degradation. Ann Neurol 2003; 53 Suppl 3:S61-70; discussion S70-2. [PMID: 12666099 DOI: 10.1002/ana.10489] [Citation(s) in RCA: 260] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Controversy has surrounded a role for apoptosis in the loss of neurons in Parkinson's disease (PD). Although a variety of evidence has supported an apoptotic contribution to PD neuronal loss particularly in the nigra, two factors have weighed against general acceptance: (1) limitations in the use of in situ 3' end labeling techniques to demonstrate nuclear DNA cleavage; and (2) the insistence that a specific set of nuclear morphological features be present before apoptotic death could be declared. We first review the molecular events that underlie apoptotic nuclear degradation and the literature regarding the unreliability of 3' DNA end labeling as a marker of apoptotic nuclear degradation. Recent findings regarding the multiple caspase-dependent or caspase-independent signaling pathways that mediate apoptotic nuclear degradation and determine the morphological features of apoptotic nuclear degradation are presented. The evidence shows that a single nuclear morphology is not sufficient to identify apoptosis and that a cytochrome c, pro-caspase 9, and caspase 3 pathways is operative in PD nigral apoptosis. BAX-dependent increases in mitochondrial membrane permeability are responsible for the release of mitochondrial factors that signal for apoptotic degradation, and increased BAX levels have been found in a subset of PD nigral neurons. Studies using immunocytochemistry in PD postmortem nigra have begun to define the premitochondrial apoptosis signaling pathways in the disease. Two, possibly interdependent, pathways have been uncovered: (1) a p53-glyceraldehyde-3-phosphate dehydrogenase (GAPDH)-BAX pathway; and (2) FAS receptor-FADD-caspase 8-BAX pathway. Based on the above, it seems unlikely that apoptosis does not contribute to PD neuronal loss, and the definition of the premitochondrial signaling pathways may allow for the development and testing of an apoptosis-based PD therapy.
Collapse
Affiliation(s)
- William G Tatton
- Department of Neurology, Mount Sinai School of Medicine, New York, NY 10029, USA.
| | | | | | | |
Collapse
|
222
|
Tatton W, Chen D, Chalmers-Redman R, Wheeler L, Nixon R, Tatton N. Hypothesis for a common basis for neuroprotection in glaucoma and Alzheimer's disease: anti-apoptosis by alpha-2-adrenergic receptor activation. Surv Ophthalmol 2003; 48 Suppl 1:S25-37. [PMID: 12852432 DOI: 10.1016/s0039-6257(03)00005-5] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Recent studies have suggested glaucomatous loss of retinal ganglion cells and their axons in Alzheimer's disease. Amyloid beta peptides and phosphorylated tau protein have been implicated in the selective regional neuronal loss and protein accumulations characteristic of Alzheimer's disease. Similar protein accumulations are not present on glaucomatous retinal ganglion cells. Neurons die in both Alzheimer's disease and glaucoma by apoptosis, although the signaling pathways for neuronal degradation appear to differ in the two diseases. Alzheimer's disease features a loss of locus ceruleus noradrenergic neurons, which send axon terminals to the brain regions suffering neuronal apoptosis and results in reductions in noradrenaline in those regions. Activation of alpha-2 adrenergic receptors reduces neuronal apoptosis, in part through a protein kinase B (Akt)-dependent signaling pathway. Loss of noradrenaline innervation facilitates neuronal apoptosis in Alzheimer's disease models and may act similarly in glaucoma. Alpha-2 adrenergic receptor agonists offer the potential to slow the neuronal loss in both diseases by compensating for lost noradrenaline innervation.
Collapse
Affiliation(s)
- William Tatton
- Department of Neurology, Mount Sinai School of Medicine, New York, New York, USA
| | | | | | | | | | | |
Collapse
|
223
|
Kawane K, Fukuyama H, Yoshida H, Nagase H, Ohsawa Y, Uchiyama Y, Okada K, Iida T, Nagata S. Impaired thymic development in mouse embryos deficient in apoptotic DNA degradation. Nat Immunol 2003; 4:138-44. [PMID: 12524536 DOI: 10.1038/ni881] [Citation(s) in RCA: 183] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2002] [Accepted: 12/03/2002] [Indexed: 02/06/2023]
Abstract
Apoptosis is often accompanied by the degradation of chromosomal DNA. Caspase-activated DNase (CAD) is an endonuclease that is activated in dying cells, whereas DNase II is present in the lysosomes of macrophages. Here, we show that CAD(-/-) thymocytes did not undergo apoptotic DNA degradation. But, when apoptotic cells were phagocytosed by macrophages, their DNA was degraded by DNase II. The thymus of DNase II(-/-)CAD(-/-) embryos contained many foci carrying undigested DNA and the cellularity was severely reduced due to a block in T cell development. The interferon-beta gene was strongly up-regulated in the thymus of DNase II(-/-)CAD(-/-) embryos, suggesting that when the DNA of apoptotic cells is left undigested, it can activate innate immunity leading to defects in thymic development.
Collapse
Affiliation(s)
- Kohki Kawane
- Department of Genetics, Osaka University Medical School, Japan
| | | | | | | | | | | | | | | | | |
Collapse
|
224
|
Nagata S, Nagase H, Kawane K, Mukae N, Fukuyama H. Degradation of chromosomal DNA during apoptosis. Cell Death Differ 2003; 10:108-16. [PMID: 12655299 DOI: 10.1038/sj.cdd.4401161] [Citation(s) in RCA: 330] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Apoptosis is often accompanied by degradation of chromosomal DNA. CAD, caspase-activated DNase, was identified in 1998 as a DNase that is responsible for this process. In the last several years, mice deficient in the CAD system have been generated. Studies with these mice indicated that apoptotic DNA degradation occurs in two different systems. In one, the DNA fragmentation is carried out by CAD in the dying cells and in the other, by lysosomal DNase II after the dying cells are phagocytosed. Several other endonucleases have also been suggested as candidate effectors for the apoptotic degradation of chromosomal DNA. In this review, we will discuss the mechanism and role of DNA degradation during apoptosis.
Collapse
Affiliation(s)
- S Nagata
- Integrated Biology Laboratories, Graduate School of Frontier Science, Japan Science and Technology Corperation, Suita, Osaka.
| | | | | | | | | |
Collapse
|
225
|
Belov GA, Romanova LI, Tolskaya EA, Kolesnikova MS, Lazebnik YA, Agol VI. The major apoptotic pathway activated and suppressed by poliovirus. J Virol 2003; 77:45-56. [PMID: 12477809 PMCID: PMC140567 DOI: 10.1128/jvi.77.1.45-56.2003] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Cells respond to poliovirus infection by switching on the apoptotic program, implementation of which is usually suppressed by viral antiapoptotic functions. We show here that poliovirus infection of HeLa cells or derivatives of MCF-7 cells was accompanied by the efflux of cytochrome c from mitochondria. This efflux occurred during both abortive infection (e.g., interrupted by guanidine-HCl and ending with apoptosis) and productive infection (leading to cytopathic effect). The former type of infection, but not the latter, was accompanied by truncation of the proapoptotic protein Bid. The virus-triggered cytochrome c efflux was suppressed by overexpression of Bcl-2. Both abortive and productive infections also resulted in a decreased level of procaspase-9, as revealed by Western blotting. In the former case, this decrease was accompanied by the accumulation of a protein with the electrophoretic mobility of active caspase-9. In contrast, in the productively infected cells, the latter protein was absent but caspase-9-related polypeptides with altered mobility could be detected. Both caspase-9 and caspase-3 were shown to be essential for the development of such hallmarks of virus-induced apoptosis as chromatin condensation, DNA degradation, and nuclear fragmentation. These and some other results suggest the following scenario. Poliovirus infection activates the apoptotic pathway, involving mitochondrial damage, cytochrome c efflux, and consecutive activation of caspase-9 and caspase-3. The apoptotic signal appears to be amplified by a loop which includes secondary processing of Bid. The implementation of the apoptotic program in productively infected cells may be suppressed, however, by the viral antiapoptotic functions, which act at a step(s) downstream of the cytochrome c efflux. The suppression appears to be caused, at least in part, by aberrant processing and degradation of procaspase-9.
Collapse
Affiliation(s)
- George A Belov
- M. P. Chumakov Institute of Poliomyelitis and Viral Encephalitides, Russian Academy of Medical Sciences, Moscow Region 142782, Russia
| | | | | | | | | | | |
Collapse
|
226
|
Abstract
Members of the Bcl-2 family are crucial integrators of survival and death signals in higher eukaryotes. Although recent studies have provided novel and quite unexpected insights into the mechanisms by which these proteins might issue life permits or death sentences in cells, we are still on the way to fully understand their modes of action. This review provides a snapshot on where we are on this journey and how we may exploit our knowledge on this family of proteins to unveil the mysteries of immune regulation.
Collapse
Affiliation(s)
- Christoph Borner
- Institute of Molecular Medicine and Cell Research, Albert-Ludwigs-University, Freiburg, Germany.
| |
Collapse
|
227
|
Roucou X, Montessuit S, Antonsson B, Martinou JC. Bax oligomerization in mitochondrial membranes requires tBid (caspase-8-cleaved Bid) and a mitochondrial protein. Biochem J 2002; 368:915-21. [PMID: 12193163 PMCID: PMC1223025 DOI: 10.1042/bj20020972] [Citation(s) in RCA: 157] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2002] [Revised: 08/20/2002] [Accepted: 08/23/2002] [Indexed: 11/17/2022]
Abstract
In response to various apoptotic stimuli, Bax, a pro-apoptotic member of the Bcl-2 family, is oligomerized and permeabilizes the mitochondrial outer membrane to apoptogenic factors, including cytochrome c. Bax oligomerization can also be induced by incubating isolated mitochondria containing endogenous Bax with recombinant tBid (caspase-8-cleaved Bid) in vitro. The mechanism by which Bax oligomerizes under these conditions is still unknown. To address this question, recombinant human full-length Bax was purified as a monomeric protein. Bax failed to oligomerize spontaneously in isolated mitochondria or in liposomes composed of either cardiolipin or lipids extracted from mitochondria. However, in the presence of tBid, the protein formed large complexes in mitochondrial membranes and induced the release of cytochrome c. tBid also induced Bax oligomerization in isolated mitochondrial outer membranes, but not in other membranes, such as plasma membranes or microsomes. Moreover, tBid-induced Bax oligomerization was inhibited when mitochondria were pretreated with protease K. The presence of the voltage-dependent anion channel was not required either for Bax oligomerization or for Bax-induced cytochrome c release. Finally, Bax oligomerization was reconstituted in proteoliposomes made from mitochondrial membrane proteins. These findings imply that tBid is necessary but not sufficient for Bax oligomerization; a mitochondrial protein is also required.
Collapse
Affiliation(s)
- Xavier Roucou
- Departement de Biologie Cellulaire, University of Geneva, 30 quai E. Ansermet, 1211 Geneva 4, Switzerland
| | | | | | | |
Collapse
|
228
|
Li YC, Fung KP, Kwok TT, Lee CY, Suen YK, Kong SK. Mitochondrial targeting drug lonidamine triggered apoptosis in doxorubicin-resistant HepG2 cells. Life Sci 2002; 71:2729-40. [PMID: 12383880 DOI: 10.1016/s0024-3205(02)02103-3] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Mitochondria play a crucial role in the induction and execution of apoptosis. Accordingly, recent suggestions have been made to use agents that directly act on mitochondria to trigger apoptosis so that drug-sensitive and-resistant tumour cells can be eliminated. To test this hypothesis, human hepatocarcinoma HepG2 and its derivative R-HepG2 with doxorubicin (Dox) resistance as a result of expression of P-glycoprotein were used to investigate the effect of lonidamine (LND), a new mitochondrial targeting drug, on the induction of apoptosis. Results from our study indicate that R-HepG2 cells were more sensitive to LND than parental cells in terms of cytotoxicity determined by alamar blue assay. Cell death induced by LND was associated with the hallmarks of apoptosis such as mitochondrial membrane depolarization, release of cytochrome c, phosphatidyl-serine externalization and DNA fragmentation. Moreover, combined treatment of cells with Dox and LND elicited more cell death. Taken together, our results suggest a potential use of LND as an anti-cancer drug to bypass drug resistance and to trigger tumour destruction through apoptosis in HepG2 and R-HepG2 cells.
Collapse
Affiliation(s)
- Y C Li
- Department of Biochemistry, The Chinese University of Hong Kong, Shatin, People's Republic of China
| | | | | | | | | | | |
Collapse
|
229
|
Mukae N, Yokoyama H, Yokokura T, Sakoyama Y, Nagata S. Activation of the innate immunity in Drosophila by endogenous chromosomal DNA that escaped apoptotic degradation. Genes Dev 2002; 16:2662-71. [PMID: 12381665 PMCID: PMC187462 DOI: 10.1101/gad.1022802] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Apoptotic cell death is accompanied by degradation of chromosomal DNA. Here, we established in Drosophila a null mutation in the gene for inhibitor of caspase-activated DNase (ICAD) by P-element insertion. We also identified a loss-of-function mutant in Drosophila for DNase II-like acid DNase. The flies deficient in the ICAD gene did not express CAD, and did not undergo apoptotic DNA fragmentation during embryogenesis and oogenesis. In contrast, the deficiency of DNase II enhanced the apoptotic DNA fragmentation in the embryos and ovary, but paradoxically, the mutant flies accumulated a large amount of DNA, particularly in the ovary. This accumulation of DNA in the DNase II mutants caused the constitutive expression of the antibacterial genes for diptericin and attacin, which are usually activated during bacterial infection. The expression of these genes was further enhanced in flies lacking both dICAD and DNase II. These results indicated that CAD and DNase II work independently to degrade chromosomal DNA during apoptosis, and if the DNA is left undigested, it can activate the innate immunity in Drosophila.
Collapse
Affiliation(s)
- Naomi Mukae
- Department of Genetics, Osaka University Medical School, Osaka 565-0871, Japan
| | | | | | | | | |
Collapse
|
230
|
van Loo G, Saelens X, van Gurp M, MacFarlane M, Martin SJ, Vandenabeele P. The role of mitochondrial factors in apoptosis: a Russian roulette with more than one bullet. Cell Death Differ 2002; 9:1031-42. [PMID: 12232790 DOI: 10.1038/sj.cdd.4401088] [Citation(s) in RCA: 462] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2002] [Revised: 06/07/2002] [Accepted: 06/11/2002] [Indexed: 01/08/2023] Open
Abstract
Mitochondria are 'life-essential' organelles for the production of metabolic energy in the form of ATP. Paradoxically mitochondria also play a key role in controlling the pathways that lead to cell death. This latter role of mitochondria is more than just a 'loss of function' resulting in an energy deficit but is an active process involving different mitochondrial proteins. Cytochrome c was the first characterised mitochondrial factor shown to be released from the mitochondrial intermembrane space and to be actively implicated in apoptotic cell death. Since then, other mitochondrial proteins, such as AIF, Smac/DIABLO, endonuclease G and Omi/HtrA2, were found to undergo release during apoptosis and have been implicated in various aspects of the cell death process. Members of the Bcl-2 protein family control the integrity and response of mitochondria to apoptotic signals. The molecular mechanism by which mitochondrial intermembrane space proteins are released and the regulation of mitochondrial homeostasis by Bcl-2 proteins is still elusive. This review summarises and evaluates the current knowledge concerning the complex role of released mitochondrial proteins in the apoptotic process.
Collapse
Affiliation(s)
- G van Loo
- Molecular Signalling and Cell Death Unit, Department of Molecular Biomedical Research, VIB, Gent University, K.L. Ledeganckstraat 35, B-9000 Ghent, Belgium
| | | | | | | | | | | |
Collapse
|
231
|
Chen M, Won DJ, Krajewski S, Gottlieb RA. Calpain and mitochondria in ischemia/reperfusion injury. J Biol Chem 2002; 277:29181-6. [PMID: 12042324 DOI: 10.1074/jbc.m204951200] [Citation(s) in RCA: 202] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Studies of ischemia/reperfusion (I/R) injury and preconditioning have shown that ion homeostasis, particularly calcium homeostasis, is critical to limiting tissue damage. However, the relationship between ion homeostasis and specific cell death pathways has not been investigated in the context of I/R. Previously we reported that calpain cleaved Bid in the absence of detectable caspase activation (1). In this study, we have shown that an inhibitor of the sodium/hydrogen exchanger prevented calpain activation after I/R. Calpain inhibitors prevented cleavage of Bid as well as the downstream indices of cell death, including DNA strand breaks, creatine kinase (CK) release, and infarction measured by triphenyl tetrazolium chloride (TTC) staining. In contrast, the broad spectrum caspase inhibitor IDN6734 was not protective in this model. To ascertain whether mitochondrial dysfunction downstream of these events was a required step, we utilized a peptide corresponding to residues 4-23 of Bcl-x(L) conjugated to the protein transduction domain of HIV TAT (TAT-BH4), which has been shown to protect mitochondria against Ca2+-induced deltaPsi(m) loss (2). TAT-BH4 attenuated CK release and loss of TTC staining, demonstrating the role of mitochondria and a pro-apoptotic Bcl-2 family member in the process leading to cell death. We propose the following pathway. (i) Reperfusion results in sodium influx followed by calcium accumulation. (ii) This leads to calpain activation, which in turn leads to Bid cleavage. (iii) Bid targets the mitochondria, causing dysfunction and release of pro-apoptotic factors, resulting in DNA fragmentation and death of the cell. Ischemia/reperfusion initiates a cell death pathway that is independent of caspases but requires calpain and mitochondrial dysfunction.
Collapse
Affiliation(s)
- Min Chen
- Scripps Research Institute and The Burnham Institute, La Jolla, California 92037, USA
| | | | | | | |
Collapse
|
232
|
Cregan SP, Fortin A, MacLaurin JG, Callaghan SM, Cecconi F, Yu SW, Dawson TM, Dawson VL, Park DS, Kroemer G, Slack RS. Apoptosis-inducing factor is involved in the regulation of caspase-independent neuronal cell death. J Cell Biol 2002; 158:507-17. [PMID: 12147675 PMCID: PMC2173837 DOI: 10.1083/jcb.200202130] [Citation(s) in RCA: 378] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2002] [Revised: 05/22/2002] [Accepted: 06/24/2002] [Indexed: 11/22/2022] Open
Abstract
Caspase-independent death mechanisms have been shown to execute apoptosis in many types of neuronal injury. P53 has been identified as a key regulator of neuronal cell death after acute injury such as DNA damage, ischemia, and excitotoxicity. Here, we demonstrate that p53 can induce neuronal cell death via a caspase-mediated process activated by apoptotic activating factor-1 (Apaf1) and via a delayed onset caspase-independent mechanism. In contrast to wild-type cells, Apaf1-deficient neurons exhibit delayed DNA fragmentation and only peripheral chromatin condensation. More importantly, we demonstrate that apoptosis-inducing factor (AIF) is an important factor involved in the regulation of this caspase-independent neuronal cell death. Immunofluorescence studies demonstrate that AIF is released from the mitochondria by a mechanism distinct from that of cytochrome-c in neurons undergoing p53-mediated cell death. The Bcl-2 family regulates this release of AIF and subsequent caspase-independent cell death. In addition, we show that enforced expression of AIF can induce neuronal cell death in a Bax- and caspase-independent manner. Microinjection of neutralizing antibodies against AIF significantly decreased injury-induced neuronal cell death in Apaf1-deficient neurons, indicating its importance in caspase-independent apoptosis. Taken together, our results suggest that AIF may be an important therapeutic target for the treatment of neuronal injury.
Collapse
Affiliation(s)
- Sean P Cregan
- Ottawa Health Research Institute, Department of Neuroscience, University of Ottawa, Ontario, Canada, K1H 8M5
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
233
|
Van Loo G, Demol H, van Gurp M, Hoorelbeke B, Schotte P, Beyaert R, Zhivotovsky B, Gevaert K, Declercq W, Vandekerckhove J, Vandenabeele P. A matrix-assisted laser desorption ionization post-source decay (MALDI-PSD) analysis of proteins released from isolated liver mitochondria treated with recombinant truncated Bid. Cell Death Differ 2002; 9:301-8. [PMID: 11859412 DOI: 10.1038/sj.cdd.4400966] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2001] [Revised: 09/18/2001] [Accepted: 09/26/2001] [Indexed: 01/18/2023] Open
Abstract
A crucial event in the process of apoptosis is caspase-dependent generation of truncated Bid (tBid), inducing release of cytochrome c. In an in vitro reconstitution system we combined purified recombinant tBid with isolated liver mitochondria and identified the released proteins using a proteomic matrix-assisted laser desorption ionization post-source decay (MALDI-PSD) approach. In order to meet physiological conditions, the concentration of tBid was chosen such that it was unable to induce cytochrome c release in mitochondria derived from liver-specific Bcl-2-transgenic mice. Several mitochondrial proteins were identified to be released in a tBid-dependent way, among which cytochrome c, DIABLO/Smac, adenylate kinase 2, acyl-CoA-binding protein, endonuclease G, polypyrimidine tract-binding protein, a type-I RNA helicase, a WD-40 repeat-containing protein and the serine protease Omi. Western blotting confirmed the absence of adenylate kinase 3, a matrix mitochondrial protein. These results demonstrate that a physiologically relevant concentration of tBid is sufficient to induce release of particular intermembrane mitochondrial proteins belonging to a broad molecular-mass range.
Collapse
Affiliation(s)
- G Van Loo
- Flanders Interuniversity Institute for Biotechnology and Ghent University, Department of Molecular Biology, Unit of Molecular Signaling and Cell Death, KL Ledeganckstraat 35, B-9000 Gent, Belgium
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
234
|
van Loo G, van Gurp M, Depuydt B, Srinivasula SM, Rodriguez I, Alnemri ES, Gevaert K, Vandekerckhove J, Declercq W, Vandenabeele P. The serine protease Omi/HtrA2 is released from mitochondria during apoptosis. Omi interacts with caspase-inhibitor XIAP and induces enhanced caspase activity. Cell Death Differ 2002; 9:20-6. [PMID: 11803371 DOI: 10.1038/sj.cdd.4400970] [Citation(s) in RCA: 237] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2001] [Revised: 10/18/2001] [Accepted: 10/18/2001] [Indexed: 11/09/2022] Open
Abstract
Proteome analysis of supernatant of isolated mitochondria exposed to recombinant tBid, a proapoptotic Bcl-2 member, revealed the presence of the serine protease Omi, also called HtrA2. This release was prevented in mitochondria derived from Bcl-2-transgenic mice. Release of Omi under apoptotic conditions was confirmed in vivo in livers from mice injected with agonistic anti-Fas antibodies and was prevented in livers from Bcl-2 transgenic mice. Omi release also occurs in apoptotic dying but not in necrotic dying fibrosarcoma L929 cells, treated with anti-Fas antibodies and TNF, respectively. The amino acid sequence reveals the presence of an XIAP interaction motif at the N-terminus of mature Omi. We demonstrate an interaction between endogeneous Omi and recombinant XIAP. Furthermore we show that endogenous Omi is involved in enhanced activation of caspases in cytosolic extracts.
Collapse
Affiliation(s)
- G van Loo
- Flanders Interuniversity Institute for Biotechnology and Ghent University, Molecular Signalling and Cell Death Unit, Department of Molecular Biology, K.L. Ledeganckstraat 35, B-9000 Ghent, Belgium
| | | | | | | | | | | | | | | | | | | |
Collapse
|
235
|
Knight RA, Petit PX. Another genotoxic agent released by mitochondrial meltdown. Cell Death Differ 2001; 8:1134-5. [PMID: 11753561 DOI: 10.1038/sj.cdd.4400956] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
|