201
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Affiliation(s)
- S T Eichhorst
- Department of Medicine II, Klinikum Grosshadern, University of Munich, Munich, Germany
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202
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Abstract
Antigen delivers both immunogenic and tolerogenic signals to lymphocytes. The outcome of antigen exposure represents a complex integration of the timing of antigen binding with signals from many other immunogenic and tolerogenic costimulatory pathways. A road map of these signalling pathways is only beginning to be charted, revealing the mechansim of action and limitations of current immunotherapeutic agents and the points of attack for new agents. Ciclosporin and tacrolimus interfere with tolerogenic signals from antigen in addition to blocking immunogenic signals, thus preventing active establishment of tolerance. Corticosteroids inhibit a key immunogenic pathway, NFkappaB, and more specific inhibitors of this pathway may allow tolerance to be actively established while immune responses are blocked. New experimental therapies aim to mimic tolerogenic antigen signals by chronically stimulating antigen receptors with antigen or antibodies to the receptor, or aim to block costimulatory pathways involving CD40 ligand, B7, or interleukin 2. Obtaining the desired response with these strategies is unpredictable because many of these signals have both tolerogenic and immunogenic roles. The cause of autoimune diseases has been determined for several rare monogenic disorders, revealing inherited deficiencies in tolerogenic costimulatory pathways such as FAS. Common autoimmune disorders may have a biochemically related pathogenesis.
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Affiliation(s)
- C C Goodnow
- Australian Cancer Research Foundation, Genetics Laboratory, Medical Genome Centre, John Curtin School of Medical Research, Australian National University, Canberra, Australia
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203
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Abstract
The death of T lymphocytes following their activation involves several signal pathways that converge on a series of proteases, known as caspases, that degrade cellular proteins and activate a DNAse. Caspases are activated through ligation of cell surface death receptors as well as via direct activation of downstream caspases, often through metabolic stress such as cytokine withdrawal or generation of oxygen radicals, that culminates in mitochondrial dysfunction and release of the pro-apoptotic molecules, cytochrome c and Smac/DIABLO. The Bcl-2 family members serve to regulate the mitochondrial membrane integrity. Recent studies are now revealing the significant contribution to the activation-induced cell death of T cells by downstream caspases such as caspase-3 and Bcl-2-homology domain 3 (BH3)-only members of the Bcl-2 family.
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Affiliation(s)
- R C Budd
- Immunobiology Program, The University of Vermont College of Medicine, Given Medical Building, D-305 05405-0068, Burlington, VT, USA.
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204
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Abstract
Apoptosis is a complex biochemical process that involves all aspects of the cell from the plasma membrane to the nucleus. Apoptosis stimuli are mediated by many different cellular processes including protein synthesis and degradation, the alteration in protein phosphorylation states, the activation of lipid second messenger systems, and disruption of normal mitochondrial function. Despite this diversity in signal transduction, all apoptotic pathways are believed to converge ultimately with the activation of caspases leading to the characteristic morphological changes of apoptosis. In this review, we discuss what is known about these pathways and its implication for normal cellular function.
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Affiliation(s)
- N B Blatt
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA
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205
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Hsu PN, Lin HH, Tu CF, Chen NJ, Wu KM, Tsai HF, Hsieh SL. Expression of human Fas ligand on mouse beta islet cells does not induce insulitis but is insufficient to confer immune privilege for islet grafts. J Biomed Sci 2001; 8:262-9. [PMID: 11385298 DOI: 10.1007/bf02256600] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Fas (CD95) and Fas ligand (FasL/CD95L) are involved in programmed cell death and the regulation of host immune responses. FasL has been shown to provide immune privilege, thus prolonging the survival of unmatched grafts in a variety of tissues, such as eyes and testis. In murine FasL (mFasL) transgenic mice, FasL provoked granulocyte infiltration and insulitis in the pancreas. We intended to study whether the expression of human FasL, instead of mFasL, on mouse beta islet cells could avoid granulocyte infiltration, and whether islet cells transgenic for FasL could be used in islet transplantation. We produced transgenic mice in which the human FasL transgene was driven by rat insulin promoter and was expressed exclusively in the pancreas islet cells in ICR mice. In contrast to mFasL transgenic mice, histochemical staining showed that the pancreas was intact in human FasL transgenic ICR mice. However, when human FasL transgenic islet cells were transplanted into allogeneic mice with streptozotocin-induced diabetes, human FasL appeared not to prolong graft survival. Intensive granulocyte infiltration into the islet grafts was observed in recipients (Balb/c mice) which received islet grafts from human FasL transgenic mice, but not from nontransgenic, allogeneic ICR mice on day 31. Our observations suggest that FasL alone is insufficient to confer immune protection, and that other environmental factors might contribute to the formation of immune privilege sites in vivo
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Affiliation(s)
- P N Hsu
- Graduate Institute of Immunology, College of Medicine, National Taiwan University, Taipei, Taiwan, ROC
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206
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Shisler JL, Moss B. Molluscum contagiosum virus inhibitors of apoptosis: The MC159 v-FLIP protein blocks Fas-induced activation of procaspases and degradation of the related MC160 protein. Virology 2001; 282:14-25. [PMID: 11259186 DOI: 10.1006/viro.2001.0834] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Molluscum contagiosum virus contains two open reading frames, MC159 and MC160, that encode proteins with death effector domains resembling those of cellular regulators of apoptosis. Previous transfection analyses indicated that the MC159 protein binds to cellular FADD and inhibits Fas-induced cytolysis. For further studies, we inserted the MC159 or MC160 gene into the genome of vaccinia virus that had its own major anti-apoptosis gene deleted. The MC159-expressing virus blocked Fas-induced activation of caspase-3 and -8, degradation of PARP, and cleavage of DNA, whereas the parental vaccinia virus did not. The MC159 protein bound to procaspase-8, in addition to FADD, and was included in a complex with Fas upon receptor activation. Although the MC160 protein associated with FADD and procaspase-8 in co-immunoprecipitation studies, no protection against morphological or biochemical changes associated with Fas-induced apoptosis were discerned and the MC160 protein itself was degraded. Co-expression of MC159, as well as other caspase inhibitors, protected the MC160 protein from degradation, suggesting a functional relationship between the two viral proteins.
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Affiliation(s)
- J L Shisler
- Laboratory of Viral Diseases, National Institutes of Health, Bethesda, Maryland 20892-0445, USA
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207
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Abstract
STUDY DESIGN An examination of surgically obtained herniated lumbar disc tissues performed by using immunohistochemical staining and the DNA nick end labeling method. OBJECTIVE To investigate the cell type that expresses Fas ligand (FasL) and any evidence of apoptosis of the disc cells in herniated lumbar disc tissues. SUMMARY OF BACKGROUND DATA The Fas/FasL system is involved in delivering a death signal that rapidly commits the cells to apoptosis. In the authors' previous study, the expression of Fas on disc cells was identified in herniated lumbar disc tissue. METHODS Twenty-three herniated lumbar disc tissues (contained disc, n = 9; noncontained disc, n = 14) were examined to investigate the cell type that expresses FasL and any evidence of apoptosis of the disc cells by using immunohistochemical staining and the DNA nick end labeling method, respectively. The percentage of FasL-positive disc cells was calculated and compared with clinical and radiologic data. RESULTS FasL was expressed in the cytoplasm of the disc cells, and nuclear DNA fragmentation in a few disc cells was identified. A higher degree of FasL expression in disc cells was found in noncontained discs than in contained discs (P < 0.05). The percentage of FasL-positive disc cells significantly increased with the patient's age (P < 0.05), but not with the degree of disc degeneration (P > 0.05). CONCLUSION The current results indicate that disc cells, after herniation, undergo apoptotic cell death via autocrine or paracrine FasL mechanisms by the disc cells themselves.
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Affiliation(s)
- J B Park
- Department of Orthopaedic Surgery, Uijongbu St. Mary's Hospital, The Catholic University of Korea, Kyunggi-do.
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208
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Abe K, Kurakin A, Mohseni-Maybodi M, Kay B, Khosravi-Far R. The complexity of TNF-related apoptosis-inducing ligand. Ann N Y Acad Sci 2001; 926:52-63. [PMID: 11193041 DOI: 10.1111/j.1749-6632.2000.tb05598.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
One of the major goals of researchers in the field of apoptosis is to understand the molecular mechanisms of the various components of the apoptotic pathways, with the hope to identify targets for novel cancer therapies. The discovery of a TNF-related, apoptosis-inducing ligand, TRAIL, that kills transformed cells with great specificity in vitro, has provided the hope that TRAIL may be used to induce cell death in tumor cells without affecting normal tissues. However, TRAIL signaling is very complex and a clear understanding of its function is necessary before it can be used in cancer therapy. Complexity of TRAIL-induced signaling is apparent from its ubiquitous expression, its ability to interact with five receptors, and its tumor-selective induction of apoptosis. The signaling events that mediate the tumor selectivity of TRAIL-induced apoptosis and the biological functions of each of the TRAIL receptors are not well characterized. This review will focus on the complexity of TRAIL and the role of c-FLIP in mediating TRAIL function.
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Affiliation(s)
- K Abe
- Department of Pathology, Beth Israel Deaconess Medical Center and Harvard Medical School, 99 Brookline Ave., RN 270F, Boston, MA 02215, USA
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209
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Melief CJ, Toes RE, Medema JP, van der Burg SH, Ossendorp F, Offringa R. Strategies for immunotherapy of cancer. Adv Immunol 2001; 75:235-82. [PMID: 10879286 DOI: 10.1016/s0065-2776(00)75006-1] [Citation(s) in RCA: 119] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
MESH Headings
- Adjuvants, Immunologic
- Animals
- Antibodies, Monoclonal/therapeutic use
- Antibodies, Neoplasm/therapeutic use
- Antigen Presentation
- Antigens, CD/physiology
- Antigens, Neoplasm/immunology
- Apoptosis
- Cancer Vaccines/therapeutic use
- Cytokines/genetics
- Cytokines/physiology
- Disease Susceptibility
- Genetic Therapy
- Humans
- Immune Tolerance
- Immunity, Innate
- Immunoglobulin Idiotypes/immunology
- Immunologic Deficiency Syndromes/complications
- Immunologic Deficiency Syndromes/immunology
- Immunotherapy/methods
- Immunotherapy, Active
- Immunotherapy, Adoptive
- Lymphocyte Cooperation
- Lymphocytes, Tumor-Infiltrating/immunology
- Mice
- Neoplasm Proteins/immunology
- Neoplasms/etiology
- Neoplasms/immunology
- Neoplasms/prevention & control
- Neoplasms/therapy
- Neoplasms, Experimental/immunology
- Neoplasms, Experimental/therapy
- Oncogenic Viruses/immunology
- Receptors, Tumor Necrosis Factor/physiology
- T-Lymphocyte Subsets/immunology
- Tumor Virus Infections/immunology
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Affiliation(s)
- C J Melief
- Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, The Netherlands
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210
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Hennino A, Bérard M, Krammer PH, Defrance T. FLICE-inhibitory protein is a key regulator of germinal center B cell apoptosis. J Exp Med 2001; 193:447-58. [PMID: 11181697 PMCID: PMC2195905 DOI: 10.1084/jem.193.4.447] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Affinity maturation of the B cell response to antigen (Ag) takes place in the germinal centers (GCs) of secondary follicles. Two sequential molecular mechanisms underpin this process. First, the B cell repertoire is diversified through hypermutation of the immunoglobulin (Ig) variable region genes. Second, mutant B cell clones with improved affinity for Ag are positively selected by Ag and CD40 ligand (L). This selection step is contingent upon "priming" of GC B cells for apoptosis. The molecular means by which B cell apoptosis is initiated and controlled in the GC remains unclear. Here, we show that GC B cell apoptosis is preceded by the rapid activation of caspase-8 at the level of CD95 death-inducing signaling complex (DISC). We found that GC B cells ex vivo display a preformed inactive DISC containing Fas-associated death domain-containing protein (FADD), procaspase-8, and the long isoform of cellular FADD-like IL-1beta-converting enzyme-inhibitory protein (c-FLIP(L)) but not the CD95L. In culture, c-FLIP(L) is rapidly lost from the CD95 DISC unless GC B cells are exposed to the survival signal provided by CD40L. Our results suggest that (a) the death receptor signaling pathway is involved in the affinity maturation of antibodies, and (b) c-FLIP(L) plays an active role in positive selection of B cells in the GC.
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Affiliation(s)
- Ana Hennino
- Institut National de la Santé et de la Recherche Médicale (INSERM), U404 Immunité et Vaccination, Lyon, Cedex 07, France
| | - Marion Bérard
- Institut National de la Santé et de la Recherche Médicale (INSERM), U404 Immunité et Vaccination, Lyon, Cedex 07, France
| | - Peter H. Krammer
- Tumor Immunology Program, German Cancer Research Center, 69120 Heidelberg, Germany
| | - Thierry Defrance
- Institut National de la Santé et de la Recherche Médicale (INSERM), U404 Immunité et Vaccination, Lyon, Cedex 07, France
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211
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Abstract
Poxviruses are large complex viruses that replicate in the cytoplasm of cells without integrating their DNA into the host genome or undergoing a latent intracellular stage. In addition to viral enzymes for DNA and RNA synthesis, poxviruses encode many proteins that modulate host responses. These include inhibitors of apoptosis induced by ligand binding to cell surface receptors, peroxides, ultraviolet light, DNA damaging agents and other cell signaling pathways.
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Affiliation(s)
- J L Shisler
- Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 4 Center Drive, Bethesda, MD 20892-0445, MSC 0445, USA
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212
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Abstract
Microgravity interferes with numerous lymphocyte functions (expression of cell surface molecules, locomotion, polyclonal and antigen-specific activation, and the protein kinase C activity in signal transduction). The latter suggests that gravity may also affect programmed cell death (PCD) in lymphocyte populations. To test this hypothesis, we investigated spontaneous, activation- and radiation-induced PCD in peripheral blood mononuclear cells exposed to modeled microgravity (MMG) using a rotating cell culture system. The results showed significant inhibition of radiation- and activation-induced apoptosis in MMG and provide insights into the potential mechanisms of this phenomenon.
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Affiliation(s)
- D Risin
- Biotechnology Program, Wyle Laboratories-Life Sciences, Systems and Services, Houston, Texas 77058, USA.
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213
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Abstract
STUDY DESIGN The expression of Fas receptor, an apoptosis-related protein, on disc cells was examined in surgically obtained disc specimens. OBJECTIVE To assess the fate of disc cells in herniated disc tissue and the difference in the degree of expression of the Fas receptor between contained and noncontained discs. SUMMARY OF BACKGROUND DATA Little is known about the fate of disc cells after herniation. METHODS Twenty-three herniated lumbar disc specimens were classified into contained discs (protrusion or subligamentous extrusion; n = 9) and noncontained discs (transligamentous extrusion or sequestration; n = 14). All specimens were stained using the avidin-biotin-peroxidase complex method. The percentage of disc cells positive for Fas receptor was calculated and compared with clinical and radiologic data. RESULTS There was a significant difference in the percentage of Fas-positive disc cells between the contained and noncontained discs (8.44 vs.- 14.29;P = 0.044). The percentage of Fas-positive disc cells correlated significantly with the patient's age (r = 0.455, P = 0.029), but not with the degree of disc degeneration on magnetic resonance imaging (r = 0.252, P = 0.214). CONCLUSION This is the first study to identify the expression of Fas receptor on disc cells in herniated disc tissue. The results show that the disc cells after herniation may undergo Fas-mediated apoptosis and that the degree of expression of Fas receptor differs depending on the type of herniation.
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Affiliation(s)
- J B Park
- Department of Orthopaedic Surgery, College of Medicine, The Catholic University of Korea, Seoul, Korea.
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214
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Abstract
Apoptosis, also called "programmed cell death", can be induced by a variety of stimuli including activation of death receptors by the corresponding death ligands. Death receptors are a subgroup of the tumor necrosis factor (TNF)/nerve growth factor (NGF) receptor superfamily and are characterized by a death domain, which is required for signal transduction. Upon apoptosis induction, caspases, a family of aspartyl-specific cysteine proteases, are activated, which are the main executioners of apoptosis. Finally, specific death substrates are cleaved, resulting in the morphologic features of apoptosis. Depending on the cell type, activation of mitochondria is of central significance for apoptosis induction. This signaling pathway can be modulated by different pro- and anti-apoptotic proteins such as Bax and Bcl-2, which are localized at the mitochondria. Furthermore, apoptosis initiation can be prevented at the death receptor level by FLICE (caspase-8)-inhibitory proteins (FLIPs). Deregulation of apoptosis is associated with diseases like cancer, autoimmunity, and AIDS. Therefore, the elucidation of cell death pathways and the identification of modulators of apoptosis have many therapeutic implications.
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Affiliation(s)
- U Sartorius
- Tumor Immunology Program, Division of Immunogenetics, German Cancer Research Center, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
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215
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Abstract
Drug resistance, to date, has primarily been attributed to increased drug export or detoxification mechanisms. Despite correlations between drug export and drug resistance, it is increasingly apparent that such mechanisms cannot fully account for chemoresistance in neoplasia. It is now widely accepted that chemotherapeutic drugs kill tumour cells by inducing apoptosis, a genetically regulated cell death programme. Evidence is emerging that the exploitation of survival pathways, which may have contributed to disease development in the first instance, may also be important in the development of the chemoresistance. This review discusses the components of and associations between multiple signalling cascades and their possible contribution to the development of neoplasia and the chemoresistant phenotype.
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Affiliation(s)
- D M O'Gorman
- Department of Biochemistry, University College Cork, Ireland
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216
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Pollard KM, Pearson DL, Hultman P, Deane TN, Lindh U, Kono DH. Xenobiotic acceleration of idiopathic systemic autoimmunity in lupus-prone bxsb mice. ENVIRONMENTAL HEALTH PERSPECTIVES 2001; 109:27-33. [PMID: 11171521 PMCID: PMC1242047 DOI: 10.1289/ehp.0110927] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The diverse genetic backgrounds of lupus-prone murine models, which produce both quantitative and qualitative differences in disease expression, may be a valuable resource for studying the influence of environmental exposure on autoimmune disease in sensitive populations. We tested this premise by exposing autoimmune-prone BXSB and the nonautoimmune C57BL/6 mice to the heavy metal mercury. Although both strains express a nonsusceptible H-2 haplotype, exposure to mercury accelerated systemic autoimmunity in both male and female BXSB mice, whereas the C57BL/6 mice were resistant. The subclasses of antichromatin antibodies elicited in BXSB mice by mercury exposure were more consistent with the predominant Th1-type response of idiopathic disease than with the Th2-type response found in mercury-induced autoimmunity (HgIA). The appearance and magnitude of both humoral and cellular features of systemic autoimmunity correlated with the mercury dose. Furthermore, environmentally relevant tissue levels of mercury were associated with exacerbated systemic autoimmunity. These studies demonstrate that xenobiotic exposure can accelerate spontaneous systemic autoimmunity, and they support the possibility that low-level xenobiotic exposure enhances susceptibility to systemic autoimmunity in genetically susceptible individuals.
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Affiliation(s)
- K M Pollard
- W.M. Keck Autoimmune Disease Center, Department of Molecular and Experimental Medicine, Scripps Research Institute, La Jolla, California 92337, USA.
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217
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Stassi G, Zeuner A, Di Liberto D, Todaro M, Ricci-Vitiani L, De Maria R. Fas-FasL in Hashimoto's thyroiditis. J Clin Immunol 2001; 21:19-23. [PMID: 11321234 DOI: 10.1023/a:1006732713634] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Hashimoto's thyroiditis is a common chronic autoimmune disease characterized by the loss of thyroid follicular cells (thyrocytes) that are gradually replaced by lymphocytic infiltration and diffuse fibrosis. These morphological findings suggested that autoreactive T-cell clones were responsible for thyrocyte destruction and hypothyroidism through effector-target cytotoxic recognition. Later, autonomous interaction between thyrocyte Fas and FasL has been proposed as a major mechanism of thyrocyte depletion in Hashimoto's thyroiditis. Here, we analyze the possible role of Fas and FasL in the pathogenesis of Hashimoto's thyroiditis. We suggest that the Fas-FasL system dictates the outcome of the autoimmune response by acting on both immune and target cells.
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Affiliation(s)
- G Stassi
- Department of Surgical, Anatomical and Oncological Sciences, University of Palermo, Italy
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218
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Müschen M, Re D, Jungnickel B, Diehl V, Rajewsky K, Küppers R. Somatic mutation of the CD95 gene in human B cells as a side-effect of the germinal center reaction. J Exp Med 2000; 192:1833-40. [PMID: 11120779 PMCID: PMC2213498 DOI: 10.1084/jem.192.12.1833] [Citation(s) in RCA: 127] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Somatic hypermutation specifically modifies rearranged immunoglobulin (Ig) genes in germinal center (GC) B cells. However, the bcl-6 gene can also acquire somatic mutations during the GC reaction, indicating that certain non-Ig genes can be targeted by the somatic hypermutation machinery. The CD95 gene, implicated in negative selection of B lymphocytes in GCs, is specifically expressed by GC B cells and was recently identified as a tumor suppressor gene being frequently mutated in (post) GC B cell lymphomas. In this study, the 5' region (5'R) and/or the last exon coding for the death domain (DD) of the CD95 gene were investigated in naive, GC, and memory B cells from seven healthy donors. About 15% of GC and memory, but not naive, B cells carried mutations within the 5'R (mutation frequency 2.5 x 10(-4) per basepair). Mutations within the DD were very rare but could be efficiently selected by inducing CD95-mediated apoptosis: in 22 apoptosis-resistant cells, 12 DD mutations were found. These results indicate that human B cells can acquire somatic mutations of the CD95 gene during the GC reaction, which potentially confers apoptosis resistance and may counteract negative selection through the CD95 pathway.
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Affiliation(s)
- Markus Müschen
- Institute for Genetics, Department of Immunology
- Department for Internal Medicine I, University of Cologne, 50931 Köln, Germany
| | - Daniel Re
- Department for Internal Medicine I, University of Cologne, 50931 Köln, Germany
| | | | - Volker Diehl
- Department for Internal Medicine I, University of Cologne, 50931 Köln, Germany
| | | | - Ralf Küppers
- Institute for Genetics, Department of Immunology
- Department for Internal Medicine I, University of Cologne, 50931 Köln, Germany
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219
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Huang MB, Bond VC. Involvement of protein kinase C in HIV-1 gp120-induced apoptosis in primary endothelium. J Acquir Immune Defic Syndr 2000; 25:375-89. [PMID: 11141237 DOI: 10.1097/00042560-200012150-00001] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
We previously showed that HIV-1 gp120-induced apoptosis in primary human umbilical vein endothelial cell cultures (HUVEC), through CCR5 and CXCR4. Here, we have found that agonists of protein kinase C (PKC), basic fibroblast growth factor (bFGF), and short exposure to low concentrations of phorbol esters were found to block gp120-induced apoptosis in HUVEC cultures. PKC antagonists, sphingosine, H7, and extended exposure of cultures to high concentrations of phorbol esters were also found to block gp120-induced apoptosis in HUVEC cultures. A significant increase in the total amount of cellular PKC enzymatic activity was observed on exposure of HUVEC to gp120. No increase in total PKC activity was observed on exposure of HUVECs to the natural ligands SDF-1alpha, or regulated-on-activation normal T-expressed and secreted (RANTES) cells, and gp120-induced PKC induction was found to be totally blocked by CXCR4 antibodies and partially blocked by the caspase 3 inhibitor, DEVD-CHO. Alternatively, CXCR4 antibodies and DEVD-CHO totally blocked apoptosis. Finally, gp120-induced effects were found to be insensitive to pertussis toxin. Accumulated evidence suggests PKC involvement at multiple points in the gp120-induced apoptotic pathway; also suggests involvement of the CXCR4 receptor internalization pathway, and potentially suggests different downstream effects of gp120-receptor interactions and natural ligand-receptor interactions.
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Affiliation(s)
- M B Huang
- Department of Biochemistry, Morehouse School of Medicine, Atlanta, Georgia 30310-1495, USA
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220
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Matsumura H, Shimizu Y, Ohsawa Y, Kawahara A, Uchiyama Y, Nagata S. Necrotic death pathway in Fas receptor signaling. J Cell Biol 2000; 151:1247-56. [PMID: 11121439 PMCID: PMC2190580 DOI: 10.1083/jcb.151.6.1247] [Citation(s) in RCA: 194] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2000] [Accepted: 10/12/2000] [Indexed: 11/23/2022] Open
Abstract
A caspase 8-deficient subline (JB6) of human Jurkat cells can be killed by the oligomerization of Fas-associated protein with death domain (FADD). This cell death process is not accompanied by caspase activation, but by necrotic morphological changes. Here, we show that the death effector domain of FADD is responsible for the FADD-mediated necrotic pathway. This process was accompanied by a loss of mitochondrial transmembrane potential (DeltaPsim), but not by the release of cytochrome c from mitochondria. Pyrrolidine dithiocarbamate, a metal chelator and antioxidant, efficiently inhibited the FADD-induced reduction of DeltaPsim and necrotic cell death. When human Jurkat, or its transformants, expressing mouse Fas were treated with Fas ligand or anti-mouse Fas antibodies, the cells died, showing characteristics of apoptosis. A broad caspase inhibitor (z-VAD-fmk) blocked the apoptotic morphological changes and the release of cytochrome c. However, the cells still died, and this cell death process was accompanied by a strong reduction in DeltaPsim, as well as necrotic morphological changes. The presence of z-VAD-fmk and pyrrolidine dithiocarbamate together blocked cell death, suggesting that both apoptotic and necrotic pathways can be activated through the Fas death receptor.
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Affiliation(s)
- Hirotaka Matsumura
- Department of Genetics, Osaka University Medical School, Osaka 565-0871, Japan
| | - Yusuke Shimizu
- Department of Genetics, Osaka University Medical School, Osaka 565-0871, Japan
| | - Yoshiyuki Ohsawa
- Department of Cell Biology and Anatomy, Osaka University Medical School, Osaka 565-0871, Japan
| | - Atsuo Kawahara
- Department of Genetics, Osaka University Medical School, Osaka 565-0871, Japan
| | - Yasuo Uchiyama
- Department of Cell Biology and Anatomy, Osaka University Medical School, Osaka 565-0871, Japan
| | - Shigekazu Nagata
- Department of Genetics, Osaka University Medical School, Osaka 565-0871, Japan
- Core Research for Evolutional Science and Technology, Japan Science and Technology Corporation, Osaka 565-0871, Japan
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221
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Involvement of Protein Kinase C in HIV-1 gp120-Induced Apoptosis in Primary Endothelium. J Acquir Immune Defic Syndr 2000. [DOI: 10.1097/00126334-200012150-00001] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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222
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Abstract
This report summarizes recent findings in the field of basic and translational apoptosis research which were presented at the 1st Conference on 'Mechanisms of Cell Death and Disease: Advances in Therapeutic Intervention' organized by the European School of Hematology and the University of Texas MD Anderson Cancer Center, 13-17 May, in Dublin, Ireland, and puts them in the context of the literature. Recent discoveries have significantly advanced the understanding of biochemical and genetic requirements of distinct apoptosis pathways (ie mitochondrial, death-receptor and endoplasmic reticulum-mediated apoptosis) and their dysregulation in disease. Progress has been made especially in the elucidation of the mechanisms of action of the Bcl-2 family members, in detail the formation of channels and their regulation in the mitochondrial membranes, conformational changes in Bax and Bak, and crosstalk of death receptor-triggered apoptosis to the mitochondria by activation of Bax via Bid. In addition, novel insights have been gained about the regulation of caspases and novel caspase signaling pathways, such as activation of caspase-12 by the endoplasmic reticulum stress response. Therapeutic applications of apoptosis manipulation include (1) the inhibition of caspases in acute and chronic neurodegenerative diseases, ie stroke, Alzheimer's or Huntington's disease by drugs and (2) sensitization of cancer cells for drug/radiation-induced apoptosis by modulation of survival signals and viral transfer of apoptosis promoting genes.
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Affiliation(s)
- P T Daniel
- Department of Hematology, Oncology, and Tumor Immunology, University Medical Center Charité, Humboldt University Berlin, Germany
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223
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Stein GM, Pfüller U, Schietzel M, Büssing A. Expression of interleukin-4 in apoptotic cells: stimulation of the type-2 cytokine by different toxins in human peripheral blood mononuclear and tumor cells. CYTOMETRY 2000; 41:261-70. [PMID: 11084611 DOI: 10.1002/1097-0320(20001201)41:4<261::aid-cyto4>3.0.co;2-s] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND Immunological reactivity is regulated by T-cell populations (type-1 and type-2 cells) via cytokine secretion, but their influence on apoptosis remains unclear. METHODS Intracellular expression of type-1 (interferon [IFN]-gamma) and type-2 (interleukin [IL]-4) cytokines and apoptosis-related molecules (Apo2. 7, Bcl-2 protein) was studied by flow cytometry in human peripheral blood mononuclear cells (PBMC), myeloma (U-266), monocytic (THP-1), and T-leukemia cells (MOLT-4) in response to toxins, which act on different intracellular targets (actinomycin D, cycloheximide, the mistletoe lectins [ML]-1 and ML-3, brefeldin A, staurosporine). RESULTS The apoptosis-inducing toxins stimulated intracellular IL-4 expression mainly in PBMC with high expression of the mitochondrial apoptosis marker, Apo2.7, but with decreased level of the anti-apoptotic Bcl-2 protein. Up-regulation of IL-4 coincided with a significant down-regulation of IFN-gamma in CD4(+) and CD8(+) cells. The inhibitor of oxidative phosphorylation, oligomycin, and the caspase inhibitor, z-VAD-fmk, abolished IL-4 expression and DNA fragmentation in the PBMC. Also in the myeloma, monocytic, and T-leukemia cells, IL-4 was mainly observed in the Apo2.7(+) apoptotic cells in response to the toxins. CONCLUSIONS We suggest that the different apoptotic toxins activate a common pathway in which IL-4 production plays a yet unknown intracellular role further downstream during apoptosis.
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Affiliation(s)
- G M Stein
- Krebsforschung Herdecke, Department of Applied Immunology, University Witten/Herdecke, Communal Hospital, Herdecke, Germany.
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224
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Stassi G, Di Liberto D, Todaro M, Zeuner A, Ricci-Vitiani L, Stoppacciaro A, Ruco L, Farina F, Zummo G, De Maria R. Control of target cell survival in thyroid autoimmunity by T helper cytokines via regulation of apoptotic proteins. Nat Immunol 2000; 1:483-8. [PMID: 11101869 DOI: 10.1038/82725] [Citation(s) in RCA: 110] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
After autoimmune inflammation, interactions between CD95 and its ligand (CD95L) mediate thyrocyte destruction in Hashimoto's thyroiditis (HT). Conversely, thyroid autoimmune processes that lead to Graves' disease (GD) result in autoantibody-mediated thyrotropin receptor stimulation without thyrocyte depletion. We found that GD thyrocytes expressed CD95 and CD95L in a similar manner to HT thyrocytes, but did not undergo CD95-induced apoptosis either in vivo or in vitro. This pattern was due to the differential production of TH1 and TH2 cytokines. Interferon gamma promoted caspase up-regulation and CD95-induced apoptosis in HT thyrocytes, whereas interleukin 4 and interleukin 10 protected GD thyrocytes by potent up-regulation of cFLIP and Bcl-xL, which prevented CD95-induced apoptosis in sensitized thyrocytes. Thus, modulation of apoptosis-related proteins by TH1 and TH2 cytokines controls thyrocyte survival in thyroid autoimmunity.
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Affiliation(s)
- G Stassi
- Department of Surgical, Anatomical and Oncological Sciences, Human Anatomy Section, University of Palermo, Italy
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225
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Walker PR, Calzascia T, Schnuriger V, Chalmers D, Saas P, Dietrich PY. Loss of Fas (CD95/APO-1) expression by antigen-specific cytotoxic T cells is reversed by inhibiting DNA methylation. Cell Immunol 2000; 206:51-8. [PMID: 11161437 DOI: 10.1006/cimm.2000.1722] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Elimination of clonally expanded peripheral CD8 T cells was thought to involve apoptosis induction mediated principally by TNF, but recently Fas (CD95/APO-1) has been shown to play a role in certain responses. Here we study Fas expression and sensitivity to its ligation on murine CD8 cells specific for the CW3 antigen expressed by transfected P815 cells. Fas was progressively downregulated after successive in vitro restimulations of antigen-specific CD8 cells, until clones became Fas negative and totally resistant to the effects of recombinant Fas ligand. In contrast, Fas expression by in vivo restimulated antigen-specific cells did not diminish. Loss of Fas expression in vitro was not totally irreversible, since it could be reinduced by inhibition of DNA methylation. Understanding how Fas may be differentially regulated in vivo and in vitro is an important issue for the optimal manipulation of T cells for adoptive immunotherapy protocols.
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Affiliation(s)
- P R Walker
- Laboratory of Tumour Immunology, Division of Oncology, University Hospital Geneva, CH-1211 Geneva 14, Switzerland.
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226
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Schmitz I, Kirchhoff S, Krammer PH. Regulation of death receptor-mediated apoptosis pathways. Int J Biochem Cell Biol 2000; 32:1123-36. [PMID: 11137452 DOI: 10.1016/s1357-2725(00)00048-0] [Citation(s) in RCA: 188] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Apoptosis or programmed cell death can be induced by a variety of stimuli including activation of death receptors. This subgroup of the TNF/NGF-receptor-superfamily activates caspases, a family of aspartyl-specific cysteine-proteases, which are the main executioners of apoptosis. Depending on the cell type, signalling pathways downstream of the death receptors can be modulated by different proteins such as Bcl-2, FLIPs, chaperones and kinases. Deregulation of apoptosis has been associated with diseases as cancer, autoimmunity and AIDS. Therefore, the identification of modulators of apoptosis has several therapeutic implications.
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Affiliation(s)
- I Schmitz
- Tumorimmunology Program, Division of Immunogenetics, German Cancer Research Centre, Im Neuenheimer Feld 280, D-69120 Heidelberg, Germany
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227
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Abstract
Apoptosis in the immune system is a fundamental process regulating lymphocyte maturation, receptor repertoire selection and homeostasis. Thus, death by apoptosis is as essential for the function of lymphocytes as growth and differentiation. This article focuses on death receptor-associated apoptosis and the role of CD95 (Apo-1/Fas)-mediated signalling in T-cell and B-cell development and during the course of an immune response. Gaining an insight into these processes improves our understanding of the pathogenesis of diseases such as cancer, autoimmunity and AIDS, and opens new approaches to rational treatment strategies.
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Affiliation(s)
- P H Krammer
- Tumorimmunology Program, German Cancer Research Center, Heidelberg, Germany
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228
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Eichhorst ST, Müller M, Li-Weber M, Schulze-Bergkamen H, Angel P, Krammer PH. A novel AP-1 element in the CD95 ligand promoter is required for induction of apoptosis in hepatocellular carcinoma cells upon treatment with anticancer drugs. Mol Cell Biol 2000; 20:7826-37. [PMID: 11003676 PMCID: PMC86378 DOI: 10.1128/mcb.20.20.7826-7837.2000] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The CD95 (also called APO-1 or Fas) system plays a major role in the induction of apoptosis in lymphoid and nonlymphoid tissues in response to a variety of extracellular signals, including chemotherapeutic drugs. Here we report that the CD95 ligand (CD95L) is upregulated in hepatoma cells upon treatment with antineoplastic drugs. Upregulation by different chemotherapeutic drugs is functionally relevant for drug-induced apoptosis and is mediated by transcriptional mechanisms. The MEKK1/JNKK pathway and a novel AP-1 element in the CD95L promoter downstream of the TATA box are required for CD95L upregulation. Thus, understanding the mechanisms of CD95-mediated apoptosis through CD95L upregulation upon treatment of hepatocellular carcinomas with chemotherapeutic drugs may contribute to the improvement of anticancer chemotherapy.
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229
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Moss B, Shisler JL, Xiang Y, Senkevich TG. Immune-defense molecules of molluscum contagiosum virus, a human poxvirus. Trends Microbiol 2000; 8:473-7. [PMID: 11044683 DOI: 10.1016/s0966-842x(00)01838-2] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Molluscum contagiosum virus encodes more than 150 proteins including some involved in host interactions that might contribute to prolonged viral replication in the skin. These include homologs of a selenocysteine-containing glutathione peroxidase, a death effector domain protein, a chemokine, a major histocompatibility complex class I molecule and an interleukin-18-binding protein.
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Affiliation(s)
- B Moss
- Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892-0445, USA.
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230
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McLellan AD, Terbeck G, Mengling T, Starling GC, Kiener PA, Gold R, Bröcker EB, Leverkus M, Kämpgen E. Differential susceptibility to CD95 (Apo-1/Fas) and MHC class II-induced apoptosis during murine dendritic cell development. Cell Death Differ 2000; 7:933-8. [PMID: 11279539 DOI: 10.1038/sj.cdd.4400734] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Disappearance of antigen presenting cells (APC) from the lymph node occurs following antigen specific interactions with T cells. We have investigated the regulation of CD95 (Apo-1/Fas) induced apoptosis during murine dendritic cell (DC) development. Consistent with the moderate levels of CD95 surface expression and low, or absent, MHC class II expression, immature DC in bone marrow cultures were highly sensitive to CD95 induced apoptosis, but insensitive to class II mediated apoptosis. In contrast, mature splenic, epidermal and bone marrow derived DC were fully resistant to CD95 induced cell death, but sensitive to class II induced apoptosis. Although caspase 3 and 8 activation was detected in immature DC undergoing CD95L-induced apoptosis, the pan-caspase inhibitor zVAD-fmk did not inhibit the early events of CD95-induced mitochondrial depolarisation or phosphatidyl serine exposure and only partially inhibited the killing of immature DC. In contrast, zVAD-fmk was completely effective in preventing CD95L mediated death of murine thymocytes. Collectively, these data do not support a major role of CD95: CD95L ligation in apoptosis of mature DC, but rather emphasise the existence of distinct pathways for the elimination of DC at different stages of maturation.
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Affiliation(s)
- A D McLellan
- Department of Dermatology, University of Würzburg, Würzburg, Germany
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231
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Maturation of dendritic cells leads to up-regulation of cellular FLICE-inhibitory protein and concomitant down-regulation of death ligand–mediated apoptosis. Blood 2000. [DOI: 10.1182/blood.v96.7.2628.h8002628_2628_2631] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Dendritic cells (DCs) disappear from lymph nodes 1 to 2 days after antigen presentation, presumably by apoptosis. To evaluate the role of death ligands in elimination of DCs, we analyzed the sensitivity of human DCs to CD95 ligand (CD95L) and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). We found mature DCs to be resistant to killing via CD95L or TRAIL, whereas only immature DCs were partially sensitive. However, all DC populations expressed CD95, TRAIL-R2, and TRAIL-R3 at comparable levels, suggesting that sensitivity to death ligand-induced DC apoptosis is not regulated at the receptor level. Interestingly, mature DCs highly expressed the caspase 8 inhibitory protein cFLIP, whereas only low levels were detected in immature DCs. Thus, death ligand sensitivity proved to be dependent on DC maturation and inversely correlated with expression levels of cFLIP. Induction of apoptosis by TRAIL or CD95L does not seem to play a role in the elimination of mature DCs, but instead might serve to regulate immature DC populations.
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232
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Maturation of dendritic cells leads to up-regulation of cellular FLICE-inhibitory protein and concomitant down-regulation of death ligand–mediated apoptosis. Blood 2000. [DOI: 10.1182/blood.v96.7.2628] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Abstract
Dendritic cells (DCs) disappear from lymph nodes 1 to 2 days after antigen presentation, presumably by apoptosis. To evaluate the role of death ligands in elimination of DCs, we analyzed the sensitivity of human DCs to CD95 ligand (CD95L) and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). We found mature DCs to be resistant to killing via CD95L or TRAIL, whereas only immature DCs were partially sensitive. However, all DC populations expressed CD95, TRAIL-R2, and TRAIL-R3 at comparable levels, suggesting that sensitivity to death ligand-induced DC apoptosis is not regulated at the receptor level. Interestingly, mature DCs highly expressed the caspase 8 inhibitory protein cFLIP, whereas only low levels were detected in immature DCs. Thus, death ligand sensitivity proved to be dependent on DC maturation and inversely correlated with expression levels of cFLIP. Induction of apoptosis by TRAIL or CD95L does not seem to play a role in the elimination of mature DCs, but instead might serve to regulate immature DC populations.
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233
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Schmidt T, Karsunky H, Frass B, Baum W, Denzel A, Möröy T. A novel protein (Fbf-1) that binds to CD95/APO-1/FAS and shows sequence similarity to trichohyalin and plectin. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1493:249-54. [PMID: 10978533 DOI: 10.1016/s0167-4781(00)00163-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The Fas/Apo-1/CD95 cell surface receptor belongs to the TNF receptor family of cell death inducing molecules. A number of cytosolic adapter proteins that mediate signal transduction of CD95 have been characterized, but some features of the molecular mechanisms of CD95-induced cell death remain elusive. We describe here a novel protein that can interact with the cytosolic domain of the murine CD95 receptor in a yeast two-hybrid assay. This novel protein was termed Fbf-1 for Fas binding factor and bears no sequence similarity to the known CD95 adapter proteins. Fbf-1 is 1173 aa long and has a theoretical molecular weight of around 130 kDa. The protein is expressed in a wide variety of tissues and is localized in the cytoplasm. Fbf-1 is a very hydrophilic protein, highly conserved between mouse and human and bears a carboxyterminal leucine heptad repeat reminiscent of leucine zipper protein interaction domains. In addition, it shows sequence similarity to trichohyalin and plectin pointing to a function as a structural protein.
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Affiliation(s)
- T Schmidt
- Institut für Zellbiologie, IFZ, Universitätsklinikum Essen, Virchowstrasse 173, D-45122, Essen, Germany
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234
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Herr I, Posovszky C, Di Marzio LD, Cifone MG, Boehler T, Debatin KM. Autoamplification of apoptosis following ligation of CD95-L, TRAIL and TNF-alpha. Oncogene 2000; 19:4255-62. [PMID: 10980599 DOI: 10.1038/sj.onc.1203776] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
CD95-L, TNF-alpha and TRAIL are death-inducing ligands (DILs) which may signal apoptosis via crosslinking of their cognate receptors. The present study shows that treatment of cells with agonistic mAB alpha APO-1 (CD95), recombinant TRAIL or TNF-alpha leads to enhanced mRNA and protein expression of each DIL with concomitant death in target cells. Immunoprecipitation of CD95-L protein from supernatant as well as neutralizing antibodies suggest DIL proteins to be cooperatively acting mediators of these cytotoxic activity. Autoamplification of the death signal was blocked in cells with a defect in apoptosis signaling either due to a dysfunctional FADD molecule or to the failure to activate JNK/SAPKs. Phosphorylation and enhanced binding of cJun and ATF-2 to DIL promoters suggest JNK/SAPKs as activators of these transcription factors following death receptor triggering. In consequence, autocrine production of DILs allows the spread of death signals to sensitive target cells. Oncogene (2000) 19, 4255 - 4262
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Affiliation(s)
- I Herr
- Division of Pediatric Oncology, German Cancer Research Center, Heidelberg, Germany
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235
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Ghia P, Caligaris-Cappio F. The indispensable role of microenvironment in the natural history of low-grade B-cell neoplasms. Adv Cancer Res 2000; 79:157-73. [PMID: 10818680 DOI: 10.1016/s0065-230x(00)79005-1] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Follicular lymphoma (FL) and B-cell chronic lymphocytic leukemia (B-CLL) are paradigmatic examples of lymphoid malignancies in which the relevant biological mechanisms are alterations in the control of apoptosis rather than an exaggerated proliferation. This explains why low-grade B-cell neoplasms still fail to be cured with current approaches. It is becoming increasingly clear that the defective apoptosis of FL and B-CLL has to be ascribed not only to intrinsic defects of the neoplastic cells, but also to extrinsic factors that influence their behavior. Malignant B cells retain the capacity to respond to microenvironmental signals, but have devised a monothematic responsiveness. They have a specific sensitivity to anti-apoptotic signals that favor their survival, whereas they seem to have become insensitive to pro-apoptotic signals. Bystander, nontumoral cells play a fundamental (though not sufficient) role both in the onset and in the progression of these diseases. The survival of leukemic cells appears to be dependent on direct cell-cell contacts. The localization of malignant B cells in bone marrow or neoplastic follicles is not a passive adhesion phenomenon but a crucial step for their survival. Bidirectional malignant lymphocyte-nontumoral cell interactions may lead to the amplification of a microenvironment able to inhibit the apoptosis of neoplastic B cells. The pressure of antigenic selection and the role of the tumor necrosis factor receptor family through the functional survival signal provided by CD40 together with the crippled death signal exerted by CD95 are new prominent characters on the stage.
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MESH Headings
- Antigens, CD/physiology
- Apoptosis/physiology
- Bone Marrow/pathology
- CD40 Antigens/physiology
- CD40 Ligand
- CD79 Antigens
- Clonal Deletion
- Cytokines/physiology
- Dendritic Cells, Follicular/metabolism
- Fas Ligand Protein
- Germinal Center/physiology
- Humans
- Leukemia, Lymphocytic, Chronic, B-Cell/pathology
- Leukemic Infiltration
- Lymphoma, B-Cell/pathology
- Lymphoma, Follicular/pathology
- Lymphoma, Non-Hodgkin/pathology
- Membrane Glycoproteins/physiology
- Neoplasm Proteins/physiology
- Receptors, Antigen, B-Cell/physiology
- Receptors, Tumor Necrosis Factor/physiology
- Stromal Cells/physiology
- Tumor Necrosis Factor-alpha/physiology
- fas Receptor/physiology
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Affiliation(s)
- P Ghia
- Department of Biomedical Sciences and Human Oncology, University of Torino, Italy
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236
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Yao PM, Tabas I. Free cholesterol loading of macrophages induces apoptosis involving the fas pathway. J Biol Chem 2000; 275:23807-13. [PMID: 10791964 DOI: 10.1074/jbc.m002087200] [Citation(s) in RCA: 148] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Macrophage death is an important feature of atherosclerosis, but the cellular mechanism for this process is largely unknown. There is increasing interest in cellular free cholesterol (FC) excess as an inducer of lesional macrophage death because macrophages accumulate large amounts of FC in vivo, and FC loading of macrophages in culture causes cell death. In this study, a cell culture model was used to explore the cellular mechanisms involved in the initial stages of FC-induced macrophage death. After 9 h of FC loading, some of the macrophages exhibited externalization of phosphatidylserine and DNA fragmentation, indicative of an apoptotic mechanism. Incubation of the cells with Z-DEVD-fluoromethylketone blocked these events, indicating dependence upon effector caspases. Macrophages from mice with mutations in either Fas or Fas ligand (FasL) demonstrated substantial resistance to FC-induced apoptosis, and FC-induced death in wild-type macrophages was blocked by an anti-FasL antibody. FC loading had no effect on the expression of cell-surface Fas but caused a small yet reproducible increase in cell-surface FasL. To determine the physiological significance of this finding, unloaded and FC-loaded Fas-deficient macrophages, which can only present FasL, were compared for their ability to induce apoptosis in secondarily added Fas-bearing macrophages. The FC-loaded macrophages were much more potent inducers of apoptosis than the unloaded macrophages, and this effect was almost completely blocked by an inhibitory anti-FasL antibody. In summary, during the early stages of FC loading of macrophages, a fraction of cells exhibited biochemical changes that are indicative of apoptosis. An important part of this event is FC-induced activation of FasL that leads to Fas-mediated apoptosis. In light of recent in vivo findings that show that apoptotic macrophages in atherosclerotic lesions express both Fas and FasL, we present a cellular model of Fas-mediated death in lesional foam cells.
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Affiliation(s)
- P M Yao
- Departments of Medicine and Anatomy and Cell Biology, Columbia University, New York, New York 10032, USA
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237
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Srivastava RK. Intracellular mechanisms of TRAIL and its role in cancer therapy. MOLECULAR CELL BIOLOGY RESEARCH COMMUNICATIONS : MCBRC 2000; 4:67-75. [PMID: 11170835 DOI: 10.1006/mcbr.2001.0265] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- R K Srivastava
- Department of Pharmaceutical Sciences, University of Maryland-School of Pharmacy, Greenebaum Cancer Center, 20 North Pine Street, Baltimore, Maryland 21201, USA
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238
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239
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Bernardini S, Bernassola F, Cortese C, Ballerini S, Melino G, Motti C, Bellincampi L, Iori R, Federici G. Modulation of GST P1-1 activity by polymerization during apoptosis. J Cell Biochem 2000. [DOI: 10.1002/(sici)1097-4644(20000615)77:4<645::aid-jcb12>3.0.co;2-9] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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240
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Sprick MR, Weigand MA, Rieser E, Rauch CT, Juo P, Blenis J, Krammer PH, Walczak H. FADD/MORT1 and caspase-8 are recruited to TRAIL receptors 1 and 2 and are essential for apoptosis mediated by TRAIL receptor 2. Immunity 2000; 12:599-609. [PMID: 10894160 DOI: 10.1016/s1074-7613(00)80211-3] [Citation(s) in RCA: 620] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Apoptosis induced by tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL/APO-2L) has been shown to exert important functions during various immunological processes. The involvement of the death adaptor proteins FADD/MORT1, TRADD, and RIP and the apoptosis-initiating caspases-8 and -10 in death signaling by the two death-inducing TRAIL receptors 1 and 2 (TRAIL-R1 and TRAIL-R2) are controversial. Analysis of the native TRAIL death-inducing signaling complex (DISC) revealed ligand-dependent recruitment of FADD/MORT1 and caspase-8. Differential precipitation of ligand-stimulated TRAIL receptors demonstrated that FADD/MORT1 and caspase-8 were recruited to TRAIL-R1 and TRAIL-R2 independently of each other. FADD/MORT1- and caspase-8-deficient Jurkat cells expressing only TRAIL-R2 were resistant to TRAIL-induced apoptosis. Thus, FADD/MORT1 and caspase-8 are essential for apoptosis induction via TRAIL-R2.
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Affiliation(s)
- M R Sprick
- Tumor Immunology Program, German Cancer Research Center (DKFZ) Heidelberg
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241
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Cahir-McFarland ED, Davidson DM, Schauer SL, Duong J, Kieff E. NF-kappa B inhibition causes spontaneous apoptosis in Epstein-Barr virus-transformed lymphoblastoid cells. Proc Natl Acad Sci U S A 2000; 97:6055-60. [PMID: 10811897 PMCID: PMC18557 DOI: 10.1073/pnas.100119497] [Citation(s) in RCA: 216] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Epstein-Barr virus (EBV) transforms B lymphocytes into lymphoblastoid cell lines usurping the Notch and tumor necrosis factor receptor pathways to effect transcription including NF-kappaB activation. To determine whether NF-kappaB activity is essential in the growth and survival of EBV-transformed lymphoblastoid cell lines, a nondegradable IkappaBalpha mutant was expressed under tetracycline regulation. Despite continued Bcl-2 and Bcl-x/L expression, NF-kappaB inhibition induced apoptosis as evidenced by poly(ADP-ribose) polymerase cleavage, nuclear condensation and fragmentation, and hypodiploid DNA content. Both caspase 3 and 8 activation and loss of mitochondrial membrane potential were observed in apoptotic cells. However, caspase inhibition failed to block apoptosis. These experiments indicate that NF-kappaB inhibitors may be useful in the therapy of EBV-induced cellular proliferation.
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Affiliation(s)
- E D Cahir-McFarland
- The Channing Laboratory and Department of Infectious Diseases, Brigham and Women's Hospital, 181 Longwood Avenue, Boston, MA 02130, USA
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242
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Kimura K, Gelmann EP. Tumor necrosis factor-alpha and Fas activate complementary Fas-associated death domain-dependent pathways that enhance apoptosis induced by gamma-irradiation. J Biol Chem 2000; 275:8610-7. [PMID: 10722700 DOI: 10.1074/jbc.275.12.8610] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Activation of either tumor necrosis factor receptor 1 or Fas induces a low level of programmed cell death in LNCaP human prostate cancer cells. We have shown that LNCaP cells are entirely resistant to gamma-radiation-induced apoptosis, but can be sensitized to irradiation by TNF-alpha. Fas activation also sensitized LNCaP cells to irradiation, causing nearly 40% cell death 72 h after irradiation. Caspase-8 was cleaved and activated after exposure to tumor necrosis factor (TNF)-alpha. However, after exposure to anti-Fas antibody caspase-8 cleavage occurred only between the 26-kDa N-terminal prodomain and the 28-kDa C-terminal region that contains the protease components. Although anti-Fas antibody plus irradiation induced apoptosis that could be blocked by the pancaspase inhibitor zVAD, there was no measurable caspase-8 activity after exposure to anti-Fas antibody. The effector caspases-6 and -7, and to a lesser extent caspase-3, were activated by TNF-alpha, but not by anti-Fas antibody. Anti-Fas antibody, like TNF-alpha also activated serine proteases that contributed to cell death. Exposure of LNCaP cells simultaneously to TNF-alpha and anti-Fas antibody CH-11 resulted in marked enhancement of apoptosis that occurred very rapidly and was still further augmented by irradiation. Rapid apoptosis that ensued from combined treatment with TNF-alpha, anti-Fas antibody, and irradiation was completely blocked either by zVAD or expression of dominant negative Fas-associated death domain. Our data shows that there are qualitative differences in caspase activation resulting from either TNF receptor 1 or Fas. Simultaneous activation of these receptors was synergistic and caused rapid epithelial cell apoptosis mediated by the caspase cascade.
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Affiliation(s)
- K Kimura
- Department of Oncology, Lombardi Cancer Center, Georgetown University, Washington, D.C. 20007-2197, USA
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243
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Abstract
The immune response is regulated not only by cell proliferation and differentiation, but also by programmed cell death, or apoptosis. In response to various stimuli, death factors bind to their respective receptors and activate the apoptotic death program in target cells. A cascade of specific proteases termed caspases mediates the apoptotic process. The activated caspases cleave various cellular components, a process that leads to morphological changes of the cells and nuclei, as well as to degradation of the chromosomal DNA. Loss-of-function mutations in the signaling molecules involved in apoptosis cause hyper-proliferation of cells in mouse and human. In contrast, exaggeration of this death cascade causes the destruction of various tissues.
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Affiliation(s)
- S Nagata
- Department of Genetics, Osaka Medical School, Japan.
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Abstract
Gastric epithelial turnover is a dynamic process. It is characterized by continuous cell proliferation, which is counterbalanced by cell loss. The biological principle that mediates the homeostasis of epithelium is programmed cell death, or apoptosis. Currently, several subtypes of apoptosis are distinguished, which are mediated by different mechanisms. Various subtypes of apoptosis also occur in the gastric epithelium under various conditions. In the normal stomach, apoptosis due to cell isolation (anoikis) mediates the physiological epithelial turnover. Albeit rarely seen in routine histology, approximately 2% of epithelial cells in the normal stomach are apoptotic. In Helicobacter pylori-induced gastritis, apoptosis and epithelial proliferation are moderately increased, with approximately 8% apoptotic epithelial cells. In gastritis, factors such as CD95 ligand or tumor necrosis factor (TNF) alpha act as death factors. They bind to specific receptors, CD95 and TNF-R, which are induced either by other cytokines, such as interferon gamma, or by Helicobacter pylori itself. In addition to CD95, H.pylorican also induce upregulation of CD95 ligand expression. Taken together, the upregulated expression of CD95, and the presence of CD95L in the close proximity to apoptotic gastric epithelial cells suggest a functional role of the CD95-CD95L system in the induction of apoptosis in H.pylori-gastritis. The role of other pathways to apoptosis is currently under study. Apart from being a biological phenomenon, apoptosis in the stomach may also have direct clinical consequences. An extreme example is given in gastric graft-vs.-host disease when epithelial denudement occurs.
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Affiliation(s)
- A von Herbay
- Institute of Pathology, University of Heidelberg, D-69120 Heidelberg, Germany.
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246
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Kipp M, Schwab BL, Przybylski M, Nicotera P, Fackelmayer FO. Apoptotic cleavage of scaffold attachment factor A (SAF-A) by caspase-3 occurs at a noncanonical cleavage site. J Biol Chem 2000; 275:5031-6. [PMID: 10671544 DOI: 10.1074/jbc.275.7.5031] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Members of the caspase family of cysteine proteases play essential roles in the disintegration of cellular architecture during apoptosis. Caspases have been grouped into subfamilies according to their preferred cleavage sites, with the "apoptotic executioner" caspase-3 as the prototype of DEXD-dependent proteases. We show here that caspase-3 is more tolerant to variations of the cleavage site than previously anticipated and present an example of a noncanonical recognition site that is efficiently cleaved by caspase-3 in vitro and in vivo. The new cleavage site was identified in human scaffold attachment factor A, one of the major scaffold attachment region DNA-binding proteins of human cells thought to be involved in nuclear architecture by fastening chromatin loops to a proteinaceous nuclear skeleton, the so-called nuclear matrix or scaffold. Using an amino-terminal recombinant construct of scaffold attachment factor A and recombinant caspase-3, we have mapped the cleavage site by matrix-assisted laser desorption ionization/time of flight mass spectrometry and Edman sequencing. We find that cleavage occurs after Asp-100 in a sequence context (SALD) that does not conform to the hitherto accepted DEXD consensus sequence of caspase-3. A point mutation, D100A, abrogates cleavage by recombinant caspase-3 in vitro and during apoptosis in vivo, confirming SALD as a novel caspase-3 cleavage site.
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Affiliation(s)
- M Kipp
- Department of Biology, University of Konstanz, D-78457 Konstanz, Germany
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Wendling U, Aktas O, Schmierer K, Zschenderlein R, Zipp F. Partial synergy of bisindolylmaleimide with apoptotic stimulus in antigen-specific T cells--implications for multiple sclerosis. J Neuroimmunol 2000; 103:69-75. [PMID: 10674991 DOI: 10.1016/s0165-5728(99)00214-3] [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: 11/29/2022]
Abstract
In multiple sclerosis (MS), induction of T cell apoptosis constitutes a promising therapeutic strategy. Recently, bisindolylmaleimide has been shown to be an effective treatment of experimental autoimmune encephalomyelitis, presumably due to enhancement of CD95-mediated T cell apoptosis. Therefore, we studied the effects of bisindolylmaleimide on human (auto)antigen-specific T cells. We observed a synergistic effect of bisindolylmaleimide with apoptotic stimulus assessed via caspase activity and annexin V-binding, but no potentiation of DNA fragmentation or cell death. Thus, bisindolylmaleimide might be useful for modulating T cell apoptosis, yet more potent substances have to be generated re-establishing immunological control over auto-reactive T cells.
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Affiliation(s)
- U Wendling
- Department of Neurology, University Hospital Charité, Schumannstr, Berlin, Germany
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248
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Abstract
The CD95 protein delivers crucial signals for lymphocyte death, and may also negatively regulate T-lymphocyte activation by preventing the influx of calcium ions from the cell's exterior. The block in calcium-ion influx occurs through the activation of acidic sphingomyelinase and the release of ceramide, a metabolite that can also induce cell death.
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249
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Körner H, Cretney E, Wilhelm P, Kelly JM, Röllinghoff M, Sedgwick JD, Smyth MJ. Tumor necrosis factor sustains the generalized lymphoproliferative disorder (gld) phenotype. J Exp Med 2000; 191:89-96. [PMID: 10620607 PMCID: PMC2195803 DOI: 10.1084/jem.191.1.89] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Tumor necrosis factor (TNF) and Fas ligand (FasL) play major roles in the homeostasis of the peripheral immune system. This becomes dramatically obvious in the absence of a functional FasL. Mice with such a deficiency develop a profound lymphadenopathy, splenomegaly, hypergammaglobulinemia, and strain-dependent systemic autoimmune disease, and succumb to premature death. It is consequently termed generalized lymphoproliferative disorder (gld). By contrast, TNF deficiency alone does not result in a striking phenotype. Thus, we sought to determine what role TNF might play in contributing to the gld phenotype by creating C57BL/6.gld.TNF(-/-) mice. Contrary to the expected outcome, mice deficient for both FasL and TNF had a substantially milder gld phenotype with regard to mortality, lymphoaccumulation, germinal center formation, and hypergammaglobulinemia. To confirm these data in a strain highly permissive for the phenotype, C3H/HeJ.gld and C3H.HeJ.lpr mice were treated with a TNF-specific monoclonal antibody. This transient neutralization of TNF also resulted in a significantly attenuated lymphoproliferative phenotype. We conclude that TNF is necessary for the full manifestation of the lymphoproliferative disorder, in particular playing a critical role in lymphoaccumulation. Most importantly, absence of TNF protects gld mice against premature death.
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Affiliation(s)
- H Körner
- Interdisziplinäres Zentrum für Klinische Forschung der Universität Erlangen-Nürnberg, D-91054 Erlangen, Germany.
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Kolbus A, Herr I, Schreiber M, Debatin KM, Wagner EF, Angel P. c-Jun-dependent CD95-L expression is a rate-limiting step in the induction of apoptosis by alkylating agents. Mol Cell Biol 2000; 20:575-82. [PMID: 10611236 PMCID: PMC85135 DOI: 10.1128/mcb.20.2.575-582.2000] [Citation(s) in RCA: 131] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Mouse 3T3 fibroblasts derived from fetuses lacking c-Jun were used to define an essential role of c-Jun, a main component of the transcription factor AP-1, in the cellular response to the alkylating agent methyl methanesulfonate (MMS). MMS represents the most potent and selective activator of the stress-induced kinases JNK/SAPK and p38, resulting in very efficient induction of c-Jun hyperphosphorylation and c-jun transcription. This agent induced apoptosis with high efficiency in wild-type cells but not in c-jun(-/-) cells. Resistance to apoptosis was accompanied by impaired expression of CD95 ligand (CD95-L), a well-known inducer of apoptosis. The addition of recombinant CD95-L restored apoptosis sensitivity in c-jun(-/-) fibroblasts. MMS-induced apoptosis in wild-type fibroblasts or human lymphocytes was strongly reduced by neutralizing CD95-L antibodies or transdominant negative FADD, confirming the importance of CD95 signalling in MMS-induced apoptosis. The loss-of-function approach in fibroblasts allowed the identification and dissection of c-Jun-dependent and -independent processes upstream or downstream of CD95 activation. We have found that c-Jun can act as a proapoptotic regulator in cells exposed to DNA damage via induction of CD95-L. Once activated, CD95-induced death signalling is not affected by the loss of c-Jun, demonstrating that only the initiation and not the execution of stress-induced apoptosis depends on c-Jun.
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Affiliation(s)
- A Kolbus
- Division of Signal Transduction and Growth Control, Deutsches Krebsforschungszentrum, D-69120 Heidelberg, Germany
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