51
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Cebecauer M, Guillaume P, Hozák P, Mark S, Everett H, Schneider P, Luescher IF. Soluble MHC-peptide complexes induce rapid death of CD8+ CTL. THE JOURNAL OF IMMUNOLOGY 2005; 174:6809-19. [PMID: 15905522 DOI: 10.4049/jimmunol.174.11.6809] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Soluble MHC-peptide (pMHC) complexes, commonly referred to as tetramers, are widely used to enumerate and to isolate Ag-specific CD8(+) CTL. It has been noted that such complexes, as well as microsphere- or cell-associated pMHC molecules compromise the functional integrity of CTL, e.g., by inducing apoptosis of CTL, which limits their usefulness for T cell sorting or cloning. By testing well-defined soluble pMHC complexes containing linkers of different length and valence, we find that complexes comprising short linkers (i.e., short pMHC-pMHC distances), but not those containing long linkers, induce rapid death of CTL. This cell death relies on CTL activation, the coreceptor CD8 and cytoskeleton integrity, but is not dependent on death receptors (i.e., Fas, TNFR1, and TRAILR2) or caspases. Within minutes of CTL exposure to pMHC complexes, reactive oxygen species emerged and mitochondrial membrane depolarized, which is reminiscent of caspase-independent T cell death. The morphological changes induced during this rapid CTL death are characteristic of programmed necrosis and not apoptosis. Thus, soluble pMHC complexes containing long linkers are recommended to prevent T cell death, whereas those containing short linkers can be used to eliminate Ag-specific CTL.
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MESH Headings
- Antioxidants/pharmacology
- Apoptosis/drug effects
- Apoptosis/immunology
- Cells, Cultured
- Clone Cells
- Cyclosporine/pharmacology
- Cytotoxicity, Immunologic/drug effects
- Cytotoxicity, Immunologic/immunology
- Dimerization
- Dose-Response Relationship, Immunologic
- Growth Inhibitors/physiology
- H-2 Antigens/physiology
- Kinetics
- Membrane Potentials/physiology
- Mitochondria/metabolism
- Mitochondria/physiology
- Necrosis
- Oligopeptides/physiology
- Reactive Oxygen Species/metabolism
- Resting Phase, Cell Cycle/drug effects
- Resting Phase, Cell Cycle/immunology
- Solubility
- T-Lymphocytes, Cytotoxic/drug effects
- T-Lymphocytes, Cytotoxic/immunology
- T-Lymphocytes, Cytotoxic/metabolism
- T-Lymphocytes, Cytotoxic/pathology
- T-Lymphocytes, Regulatory/drug effects
- T-Lymphocytes, Regulatory/immunology
- T-Lymphocytes, Regulatory/pathology
- beta-Alanine/analogs & derivatives
- beta-Alanine/pharmacology
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Affiliation(s)
- Marek Cebecauer
- Ludwig Institute for Cancer Research, Lausanne Branch, Epalinges, Switzerland
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52
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D’Agostino DM, Silic-Benussi M, Hiraragi H, Lairmore MD, Ciminale V. The human T-cell leukemia virus type 1 p13II protein: effects on mitochondrial function and cell growth. Cell Death Differ 2005; 12 Suppl 1:905-15. [PMID: 15761473 PMCID: PMC3057663 DOI: 10.1038/sj.cdd.4401576] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
p13(II) of human T-cell leukemia virus type 1 (HTLV-1) is an 87-amino-acid protein that is targeted to the inner mitochondrial membrane. p13(II) alters mitochondrial membrane permeability, producing a rapid, membrane potential-dependent influx of K(+). These changes result in increased mitochondrial matrix volume and fragmentation and may lead to depolarization and alterations in mitochondrial Ca(2+) uptake/retention capacity. At the cellular level, p13(II) has been found to interfere with cell proliferation and transformation and to promote apoptosis induced by ceramide and Fas ligand. Assays carried out in T cells (the major targets of HTLV-1 infection in vivo) demonstrate that p13(II)-mediated sensitization to Fas ligand-induced apoptosis can be blocked by an inhibitor of Ras farnesylation, thus implicating Ras signaling as a downstream target of p13(II) function.
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Affiliation(s)
- DM D’Agostino
- Department of Oncology and Surgical Sciences, University of Padova, Padova 35128, Italy
| | - M Silic-Benussi
- Department of Oncology and Surgical Sciences, University of Padova, Padova 35128, Italy
| | - H Hiraragi
- Center for Retrovirus Research and Department of Veterinary Biosciences, College of Veterinary Medicine, Columbus, OH 43210, USA
| | - MD Lairmore
- Center for Retrovirus Research and Department of Veterinary Biosciences, College of Veterinary Medicine, Columbus, OH 43210, USA
- Comprehensive Cancer Center and Richard J. Solove Research Institute, The Ohio State University, Columbus, OH 43210, USA
- Department of Molecular Virology, Immunology, and Medical Genetics, The Ohio State University, Columbus, OH 43210, USA
| | - V Ciminale
- Department of Oncology and Surgical Sciences, University of Padova, Padova 35128, Italy
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53
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Abstract
The permeability transition pore (PTP) regulates the structural re-organization of mitochondria in response to changes in cellular Ca(2+) and is thought to be an important participant in mitochondrial responses to cell death signals. Although the proteins forming the PTP have yet to be rigorously identified, recent examination of the response of mitochondria, cells and tissues lacking putative components of the PTP have been reported. Studies on mitochondria lacking cyclophilin D (CyP-D) have proved that this protein is the target for PTP inhibition by CsA; yet they have also unequivocally demonstrated that the PTP can form and open in the absence of CyP-D. Likewise, studies in mice lacking the two adenine nucleotide translocators expressed in this species have shown that a functional PTP can form in the absence of these proteins. Thus, the inner mitochondrial membrane components of the PTP remain to be identified, and the absence of CyP-D may not preclude PTP opening in vivo--a finding that questions the conclusion that the PTP participates in cell death pathways only in response to a restricted set of challenges.
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Affiliation(s)
- Michael Forte
- Vollum Institute, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239, USA.
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54
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Basso E, Fante L, Fowlkes J, Petronilli V, Forte MA, Bernardi P. Properties of the permeability transition pore in mitochondria devoid of Cyclophilin D. J Biol Chem 2005; 280:18558-61. [PMID: 15792954 DOI: 10.1074/jbc.c500089200] [Citation(s) in RCA: 628] [Impact Index Per Article: 33.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
We have studied the properties of the permeability transition pore (PTP) in mitochondria from the liver of mice where the Ppif gene encoding for mitochondrial Cyclophilin D (CyP-D) had been inactivated. Mitochondria from Ppif-/- mice had no CyP-D and displayed a striking desensitization of the PTP to Ca2+, in that pore opening required about twice the Ca2+ load necessary to open the pore in strain-matched, wild-type mitochondria. Mitochondria lacking CyP-D were insensitive to Cyclosporin A (CsA), which increased the Ca2+ retention capacity only in mitochondria from wild-type mice. The PTP response to ubiquinone 0, depolarization, pH, adenine nucleotides, and thiol oxidants was similar in mitochondria from wild-type and Ppif-/- mice. These experiments demonstrate that (i) the PTP can form and open in the absence of CyP-D, (ii) that CyP-D represents the target for PTP inhibition by CsA, and (iii) that CyP-D modulates the sensitivity of the PTP to Ca2+ but not its regulation by the proton electrochemical gradient, adenine nucleotides, and oxidative stress. These results have major implications for our current understanding of the PTP and its modulation in vitro and in vivo.
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Affiliation(s)
- Emy Basso
- Department of Biomedical Sciences and Consiglio Nazionale delle Ricerche Institute of Neuroscience, University of Padova, Viale Giuseppe Colombo 3, I-35121 Padova, Italy
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55
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Petersen DR. Alcohol, iron-associated oxidative stress, and cancer. Alcohol 2005; 35:243-9. [PMID: 16054986 DOI: 10.1016/j.alcohol.2005.03.013] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2005] [Revised: 03/18/2005] [Accepted: 03/25/2005] [Indexed: 12/22/2022]
Abstract
Oxidative stress is recognized to play an important role in the initiation and promotion events of carcinogenesis. Alcoholic liver disease is associated with significant oxidative stress as well as the hepatic accumulation of iron, a transition element also documented to initiate oxidative stress. The combined prooxidant potential of ethanol and iron is at least additive and possibly synergistic with respect to inducing hepatocellular oxidative stress and antioxidant depletion. One cellular consequence of sustained oxidative stress and redox imbalance resulting from the combined actions of alcohol and iron is lipid peroxidation, resulting in the production of aldehydic products such as 4-hydroxy-2-nonenal, which has been linked to site-specific mutations of the p53 gene. In addition, the accumulation of iron in hepatic macrophage isolated from laboratory animals chronically ingesting alcohol is associated with activation of nuclear factor-kappa B and production of tumor necrosis factor-alpha, providing a proinflammatory cellular environment also favorable for initiation and promotion of carcinogenesis. Consequently, there is persuasive evidence that the potential of ethanol and iron to induce oxidative stress may be an important pathogenic mechanism for the increased occurrence of hepatocellular carcinoma in individuals with hepatic iron overload who ingest alcohol.
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Affiliation(s)
- Dennis R Petersen
- Department of Pharmaceutical Sciences, Box C238, University of Colorado Health Sciences Center, 4200 East 9th Avenue, Denver, CO 80262, USA.
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56
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Ding WX, Yin XM. Dissection of the multiple mechanisms of TNF-alpha-induced apoptosis in liver injury. J Cell Mol Med 2005. [PMID: 15601573 DOI: 10.1111/j.1582-4934.2004.tb00469.x/pdf] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Tumor necrosis factor (TNF)-alpha-induced hepatocyte apoptosis is implicated in a wide range of liver diseases including viral hepatitis, alcoholic hepatitis, ischemia/reperfusion liver injury, and fulminant hepatic failure. TNF-alpha exerts a variety of effects that are mediated mainly by TNF-receptor 1 (TNF-R1) in cell death. The activation of TNF-R1 leads to the activation of multiple apoptotic pathways involving the activation of the pro-death Bcl-2 family proteins, reactive oxygen species, C-Jun NH2-terminal kinase, cathepsin B, acidic sphingomyelinase and neutral sphingomyelinase. These pathways are closely interlinked and mainly act on mitochondria, which release the apoptogenic factors and other events, resulting in apoptosis. This article reviews the recent progress in the molecular mechanisms of TNF-alpha-induced apoptosis in hepatocytes, and discusses how these molecular findings are shaping our understanding of the pathogenesis of liver diseases and our strategy to develop novel therapeutics.
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Affiliation(s)
- Wen-Xing Ding
- Department of Pathology, University of Pittsburgh, School of Medicine, 3550 Terrace Street, Pittsburgh, PA 15261, USA
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57
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Abstract
Tumor necrosis factor (TNF)-alpha-induced hepatocyte apoptosis is implicated in a wide range of liver diseases including viral hepatitis, alcoholic hepatitis, ischemia/reperfusion liver injury, and fulminant hepatic failure. TNF-alpha exerts a variety of effects that are mediated mainly by TNF-receptor 1 (TNF-R1) in cell death. The activation of TNF-R1 leads to the activation of multiple apoptotic pathways involving the activation of the pro-death Bcl-2 family proteins, reactive oxygen species, C-Jun NH2-terminal kinase, cathepsin B, acidic sphingomyelinase and neutral sphingomyelinase. These pathways are closely interlinked and mainly act on mitochondria, which release the apoptogenic factors and other events, resulting in apoptosis. This article reviews the recent progress in the molecular mechanisms of TNF-alpha-induced apoptosis in hepatocytes, and discusses how these molecular findings are shaping our understanding of the pathogenesis of liver diseases and our strategy to develop novel therapeutics.
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Affiliation(s)
- Wen-Xing Ding
- Department of Pathology, University of Pittsburgh, School of Medicine, 3550 Terrace Street, Pittsburgh, PA 15261, USA
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58
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D'Agostino DM, Bernardi P, Chieco-Bianchi L, Ciminale V. Mitochondria as Functional Targets of Proteins Coded by Human Tumor Viruses. Adv Cancer Res 2005; 94:87-142. [PMID: 16096000 DOI: 10.1016/s0065-230x(05)94003-7] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Molecular analyses of tumor virus-host cell interactions have provided key insights into the genes and pathways involved in neoplastic transformation. Recent studies have revealed that the human tumor viruses Epstein-Barr virus (EBV), Kaposi's sarcoma-associated herpesvirus (KSHV), human papillomavirus (HPV), hepatitis B virus (HBV), hepatitis C virus (HCV), and human T-cell leukemia virus type 1 (HTLV-1) express proteins that are targeted to mitochondria. The list of these viral proteins includes BCL-2 homologues (BHRF1 of EBV; KSBCL-2 of KSHV), an inhibitor of apoptosis (IAP) resembling Survivin (KSHV K7), proteins that alter mitochondrial ion permeability and/or membrane potential (HBV HBx, HPV E[wedge]14, HCV p7, and HTLV-1 p13(II)), and K15 of KSHV, a protein with undefined function. Consistent with the central role of mitochondria in energy production, cell death, calcium homeostasis, and redox balance, experimental evidence indicates that these proteins have profound effects on host cell physiology. In particular, the viral BCL-2 homologues BHRF1 and KSBCL-2 inhibit apoptosis triggered by a variety of stimuli. HBx, p7, E1[wedge]4, and p13(II) exert powerful effects on mitochondria either directly due to their channel-forming activity or indirectly through interactions with endogenous channels. Further investigation of these proteins and their interactions with mitochondria will provide important insights into the mechanisms of viral replication and tumorigenesis and could aid in the discovery of new targets for anti-tumor therapy.
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Affiliation(s)
- Donna M D'Agostino
- Department of Oncology and Surgical Sciences, University of Padova, Padova 35128, Italy
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