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Ha HJ, Chun HL, Park HH. Assembly of platforms for signal transduction in the new era: dimerization, helical filament assembly, and beyond. Exp Mol Med 2020; 52:356-66. [PMID: 32139779 DOI: 10.1038/s12276-020-0391-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2020] [Accepted: 01/31/2020] [Indexed: 11/08/2022] Open
Abstract
Supramolecular organizing center (SMOC)-mediated signal transduction is an emerging concept in the field of signal transduction that is ushering in a new era. The formation of location-specific, higher-order SMOCs is particularly important for cell death and innate immune signaling processes. Several protein interaction domains, including the death domain (DD) superfamily and the CIDE domain, are representative mediators of SMOC assembly in cell death and innate immune signaling pathways. DD superfamily- and CIDE domain-containing proteins form SMOCs that activate various caspases and provide signaling scaffold platforms. These assemblies can lead to signal transduction and amplification during signaling events. In this review, we summarize recent findings on the molecular basis of DD superfamily- and CIDE domain-mediated SMOC formation. Improved understanding of large molecular signaling complexes that form during innate (nonspecific) immune responses could help develop treatments for multiple diseases including cancer. Correct cell signaling requires precise protein interactions and binding, which are mediated by specific sites on the surface of the protein molecules involved. Innate immune responses and cell death mechanisms rely on such protein interactions, and defects can cause signaling abnormalities and trigger disease. Hyun Ho Park and co-workers at Chung-Ang University in Seoul, South Korea, reviewed recent insights into the presence of supramolecular organizing centers (SMOCs), localized complexes of signaling proteins that form during immune responses. The researchers highlight existing understanding of SMOC assembly processes. A better understanding of SMOCs will help to explain enzyme activation, signal amplification and cell signaling control mechanisms.
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Park HH. Domain swapping of death domain superfamily: Alternative strategy for dimerization. Int J Biol Macromol 2019; 138:565-572. [DOI: 10.1016/j.ijbiomac.2019.07.139] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 07/22/2019] [Accepted: 07/23/2019] [Indexed: 01/20/2023]
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Jiang Z, Li H, Qiao J, Yang Y, Wang Y, Liu W, Han B. Potential Analysis and Preparation of Chitosan Oligosaccharides as Oral Nutritional Supplements of Cancer Adjuvant Therapy. Int J Mol Sci 2019; 20:E920. [PMID: 30791594 DOI: 10.3390/ijms20040920] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 02/14/2019] [Accepted: 02/17/2019] [Indexed: 02/07/2023] Open
Abstract
Cancer is considered to have an adverse influence on health around the world. Chitosan, a linear polysaccharide that contains copolymers of β-1-4 linked d-glucosamine and N-acetyl-d-glucosamine units, has been widely used in the field of biomedicine, owing to its nontoxicity, biocompatibility, biodegradability, and hemocompatibility. This study was aimed at preparing the chitosan oligosaccharides (COS) and examining its ability on suppressing lung cancer in vitro and in vivo. Human non-small-cell lung cancer A549 cells model and C57BL/6 mice bearing lung cancer model were adopted. COS showed inhibition on the viability and proliferation of lung carcinoma cells (A549) in time-dependent manners, but no cytotoxicity to human liver cell (HL-7702). Moreover, COS could significantly increase Bax expression of A549 cells while decreasing Bcl-2 expression. COS supplementation significantly inhibited the growth of Lewis tissues and promoted necrosis of tumor cells in vivo. After treatment with COS, significantly elevated concentrations of Bax and reduced expression of Bcl-2 in tumor tissues, as well as elevated levels of TNF-α, IL-2, Fas and Fas-L in mice serum were observed (p < 0.05). In conclusion, COS had certain anti-tumor effects and potential application as a synergic functional food ingredient to prevent cancer.
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Strasser A, Vaux DL. Viewing BCL2 and cell death control from an evolutionary perspective. Cell Death Differ 2018; 25:13-20. [PMID: 29099481 DOI: 10.1038/cdd.2017.145] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2017] [Revised: 06/14/2017] [Accepted: 08/03/2017] [Indexed: 12/22/2022] Open
Abstract
The last 30 years of studying BCL2 have brought cell death research into the molecular era, and revealed its relevance to human pathophysiology. Most, if not all metazoans use an evolutionarily conserved process for cellular self destruction that is controlled and implemented by proteins related to BCL2. We propose the anti-apoptotic BCL2-like and pro-apoptotic BH3-only members of the family arose through duplication and modification of genes for the pro-apoptotic multi-BH domain family members, such as BAX and BAK1. In that way, a cell suicide process that initially evolved as a mechanism for defense against intracellular parasites was then also used in multicellular organisms for morphogenesis and to maintain the correct number of cells in adults by balancing cell production by mitosis.
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Pastak M, Kleff V, Saban DR, Czugala M, Steuhl KP, Ergün S, Singer BB, Fuchsluger TA. Gene Therapy for Modulation of T-Cell-Mediated Immune Response Provoked by Corneal Transplantation. Hum Gene Ther 2017; 29:467-479. [PMID: 28990426 DOI: 10.1089/hum.2017.044] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Corneal transplantation (keratoplasty) is the most common type of tissue replacement in the world. The increased rate of graft rejection after keratoplasty is a central problem for repeated transplantations and in inflamed host corneas. It has been shown that apoptosis of grafted epithelium has a role in corneal allograft rejection. This study focused on the T-cell response triggered in BALB/c mice after allogeneic corneal transplantation with and without anti-apoptotic p35-transduced epithelium. To restrict p35 expression to the epithelial cells, modified allogeneic composite grafts were created. As a result, it was found that the proportion of alloreactive CD4+ T cells in postoperatively removed cervical lymph nodes was reduced in the p35-transduced group compared to the allogeneic control group. Diminished priming of the CD4+ T cells was supported by significantly decreased proliferation and lower interferon gamma secretion when compared to allogeneic engraftments. The reduced priming of CD4+ lymphocytes is the first confirmation of the functionality of p35 in the epithelium of corneal grafts to alter the development of the recipient's immune response. Thus, modification of allosensibilization seems to be a promising tool for reducing graft-mediated immune response following corneal transplantation.
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Affiliation(s)
- Marko Pastak
- 1 Institute of Anatomy, University of Duisburg-Essen Faculty of Medicine , Essen, Germany
- 2 Eye Clinic of Tartu University Hospital , Tartu, Estonia
| | - Veronika Kleff
- 1 Institute of Anatomy, University of Duisburg-Essen Faculty of Medicine , Essen, Germany
| | | | - Marta Czugala
- 4 Department of Ophthalmology, Erlangen University Hospital , Erlangen, Germany
| | - Klaus-Peter Steuhl
- 5 Department of Ophthalmology, Essen University Hospital , Essen, Germany
| | - Süleyman Ergün
- 6 Institute of Anatomy and Cellular Biology, Julius-Maximilians-University , Würzburg, Germany
| | - Bernhard B Singer
- 1 Institute of Anatomy, University of Duisburg-Essen Faculty of Medicine , Essen, Germany
| | - Thomas A Fuchsluger
- 4 Department of Ophthalmology, Erlangen University Hospital , Erlangen, Germany
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Thomas SA, Vasudevan S, Thamkachy R, Lekshmi SU, Santhoshkumar TR, Rajasekharan KN, Sengupta S. Upregulation of DR5 receptor by the diaminothiazole DAT1 [4-amino-5-benzoyl-2-(4-methoxy phenyl amino) thiazole] triggers an independent extrinsic pathway of apoptosis in colon cancer cells with compromised pro and antiapoptotic proteins. Apoptosis 2013; 18:713-26. [PMID: 23435998 DOI: 10.1007/s10495-013-0826-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Mitochondria mediated signalling is the more common way of apoptosis induction exhibited by many chemotherapeutic agents in cancer cells. Death receptor mediated signalling for apoptosis in many cells also requires further amplification from the mitochondrial pathway activation through tBid. Thus the potential of most chemotherapeutic agents in tumours with intrinsic apoptosis resistance due to changes in molecules involved in the mitochondrial pathway is limited. Diaminothiazoles were shown earlier to bind to tubulin thereby exhibiting cytotoxicity towards different cancer cells. We observed that the lead diaminothiazole, DAT1 [4-amino-5-benzoyl-2-(4-methoxy phenyl amino) thiazole] could induce apoptosis in the colon cancer cell line HCT116 by both pathways. However, in contrast to many other chemotherapeutic agents, DAT1 triggered apoptosis where the intrinsic pathway was blocked by changing the pro and antiapoptotic proteins. An independent extrinsic pathway activation triggered by the upregulation of DR5 receptor accounted for that. The induction of DR5 occurred in the transcriptional level and the essential role of DR5 was confirmed by the fact that siRNA downregulation of DR5 significantly reduced DAT1 induced apoptosis. HCT116 cells were earlier shown to have a type II response for apoptosis induction where extrinsic pathway was connected to the intrinsic pathway via the mediator protein tBid. Our finding thus indicates that the signalling events in the manifestation of apoptosis depend not only on the cancer cell type, but also on the inducer. Our results also place diaminothiazoles in a promising position in the treatment of tumours with compromised apoptotic factors.
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Affiliation(s)
- Sannu A Thomas
- Division of Cancer Research, Rajiv Gandhi Centre for Biotechnology, Trivandrum 695014, India
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Gang GT, Kim YH, Noh JR, Kim KS, Jung JY, Shong M, Hwang JH, Lee CH. Protective role of NAD(P)H:quinone oxidoreductase 1 (NQO1) in cisplatin-induced nephrotoxicity. Toxicol Lett 2013; 221:165-75. [PMID: 23831944 DOI: 10.1016/j.toxlet.2013.06.239] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Revised: 06/26/2013] [Accepted: 06/27/2013] [Indexed: 10/26/2022]
Abstract
Although cisplatin is widely used as an anti-cancer agent, its use is significantly limited because of its tendency to induce nephrotoxicity through poorly understood mechanisms. NAD(P)H:quinone oxidoreductase 1 (NQO1) is well known to regulate ROS generation. The purpose of this study was to investigate whether NQO1 modulates cisplatin-induced renal failure associated with NADPH oxidase (NOX)-derived ROS production in an animal model. NQO1-/- mice were treated with cisplatin (18 mg/kg) and renal function, oxidative stress, and tubular apoptosis were assessed. NQO1-/- mice showed increased blood urea nitrogen and creatinine levels, tubular damage, oxidative stress, and apoptosis. In accordance with these results, the cellular NADPH/NADP ratio and NOX activity were markedly increased in the kidneys of NQO1-/- mice compared to NQO1+/+ mice. In addition, activation of NQO1 by βL treatment significantly improved renal dysfunction and reduced tubular cell damage, oxidative stress, and apoptosis. This study demonstrates that NQO1 protects cells against renal failure induced by cisplatin, and that this effect is mediated by decreased NOX activity via cellular NADPH/NADP modulation. These results provide convincing evidence that NQO1 might be beneficial for ameliorating renal failure induced by cisplatin.
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Affiliation(s)
- Gil-Tae Gang
- Laboratory Animal Center, Korea Research Institute of Bioscience and Biotechnology-KRIBB, 125 Gwahak-ro, Yuseong-gu, Daejeon 305-806, Republic of Korea
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Gomes FM, Carvalho DB, Machado EA, Miranda K. Ultrastructural and functional analysis of secretory goblet cells in the midgut of the lepidopteran Anticarsia gemmatalis. Cell Tissue Res 2013; 352:313-26. [PMID: 23397424 DOI: 10.1007/s00441-013-1563-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2012] [Accepted: 01/03/2013] [Indexed: 11/25/2022]
Abstract
Defoliation caused by Anticarsia gemmatalis larvae affects the commercial production of the soybean. Although regulation of the digestion of soybean components has become part of the suggested strategy to overcome problems caused by Anticarsia larvae, few studies have focused on the morphological and cellular aspects of Anticarsia intestinal tissue. We have therefore further analyzed the morphology and ultrastructure of the midgut of 5th instar larvae of A. gemmatalis. Dissected midgut was subjected to chemical or cryo-fixation and then to several descriptive and analytical techniques associated with both light and electron microscopy in order to correlate anatomical and physiological aspects of this organ. Histological analysis revealed typical anatomy composed of a cell layer limited by a peritrophic membrane. The identified lepidoptera-specific goblet cells were shown to contain several mitochondria inside microvilli of the goblet cell cavity and a vacuolar H(+)-ATPase possibly coupled to a K(+)-pumping system. Columnar cells were present and exhibited microvilli dispersed along the apical region that also presented secretory characteristics. We additionally found evidence for the secretion of polyphosphate (PolyP) into the midgut, a result corroborating previous reports suggesting an excretion route from the goblet cell cavity toward the luminal space. Thus, our results suggest that the Anticarsia midgut not only possesses several typical lepidopteran features but also presents some unique aspects such as the presence of a tubular network and PolyP-containing apocrine secretions, plus an apparent route for the release of cellular debris by the goblet cells.
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Affiliation(s)
- F M Gomes
- Instituto de Biofísica Carlos Chagas Filho and Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagens, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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Abstract
Spinal cord injury is a major medical problem worldwide. Unfortunately, we still do not have suitable therapeutic agents for the treatment of spinal cord injury and prevention of its devastating consequences. Scientists and physicians are baffled by the challenges of controlling progressive neurodegeneration in spinal cord injury, which has not been healed with any currently-available treatments. Although extensive work has been carried out to better understand the pathophysiology of spinal cord injury, our current understanding of the repair mechanisms of secondary injury processes is still meager. Several investigators reported the crucial role played by various proteases after spinal cord injury. Understanding the beneficial and harmful roles these proteases play after spinal cord injury will allow scientists to plan and design appropriate treatment strategies to improve functional recovery after spinal cord injury. This review will focus on various proteases such as matrix metalloproteinases, cysteine proteases, and serine proteases and their inhibitors in the context of spinal cord injury.
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Affiliation(s)
- Krishna Kumar Veeravalli
- Department of Cancer Biology and Pharmacology, University of Illinois College of Medicine at Peoria, Peoria, Illinois 61605, USA
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Abstract
Systemic lupus erythematosus (SLE) is characterized by abnormal activation and cell death signaling within the immune system. Activation, proliferation, or death of cells of the immune system is dependent on controlled reactive oxygen intermediates (ROI) production and ATP synthesis in mitochondria. The mitochondrial transmembrane potential (∆ψ (m)) reflects the energy stored in the electrochemical gradient across the inner mitochondrial membrane which, in turn, is used by F(0)F(1)-ATPase to convert ADP to ATP during oxidative phosphorylation. Mitochondrial hyperpolarization (MHP) and transient ATP depletion represent early and reversible steps in T cell activation and apoptosis. By contrast, T lymphocytes of patients with SLE exhibit elevated ∆ψ (m), i.e., persistent mitochondrial hyperpolarization (MHP), cytoplasmic alkalinization, increased ROI production, as well as diminished levels of intracellular glutathione and ATP. Increased production of nitric oxide has been identified as a cause of MHP and increased mitochondrial biogenesis. Oxidative stress affects signaling through the T cell receptor as well as activity of redox--sensitive caspases. ATP depletion causes diminished activation-induced apoptosis and sensitizes lupus T cells to necrosis. Activation of the mammalian target of rapamycin (mTOR) has recently emerged as a key sensor of MHP and mediator of enhanced Ca(2+) flux in lupus T cells.
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Affiliation(s)
- Andras Perl
- Department of Medicine, State University of New York, Upstate Medical University, College of Medicine, Syracuse, NY, USA.
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Carinhas N, Robitaille AM, Moes S, Carrondo MJT, Jenoe P, Oliveira R, Alves PM. Quantitative proteomics of Spodoptera frugiperda cells during growth and baculovirus infection. PLoS One 2011; 6:e26444. [PMID: 22039490 PMCID: PMC3196586 DOI: 10.1371/journal.pone.0026444] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2011] [Accepted: 09/27/2011] [Indexed: 01/24/2023] Open
Abstract
Baculovirus infection of Spodoptera frugiperda cells is a system of choice to produce a range of recombinant proteins, vaccines and, potentially, gene therapy vectors. While baculovirus genomes are well characterized, the genome of S. frugiperda is not sequenced and the virus-host molecular interplay is sparsely known. Herein, we describe the application of stable isotope labeling by amino acids in cell culture (SILAC) to obtain the first comparative proteome quantitation of S. frugiperda cells during growth and early baculovirus infection. The proteome coverage was maximized by compiling a search database with protein annotations from insect species. Of interest were differentially proteins related to energy metabolism, endoplasmic reticulum and oxidative stress, yet not investigated in the scope of baculovirus infection. Further, the reduced expression of key viral-encoded proteins early in the infection cycle is suggested to be related with decreased viral replication at high cell density culture. These findings have implications for virological research and improvement of baculovirus-based bioprocesses.
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Affiliation(s)
- Nuno Carinhas
- Instituto de Tecnologia Química e Biológica-Universidade Nova de Lisboa/Instituto de Biologia Experimental e Tecnológica, Oeiras, Portugal
| | - Aaron Mark Robitaille
- Department of Biochemistry, Biozentrum of the University of Basel, Basel, Switzerland
| | - Suzette Moes
- Department of Biochemistry, Biozentrum of the University of Basel, Basel, Switzerland
| | - Manuel José Teixeira Carrondo
- Instituto de Tecnologia Química e Biológica-Universidade Nova de Lisboa/Instituto de Biologia Experimental e Tecnológica, Oeiras, Portugal
- Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
| | - Paul Jenoe
- Department of Biochemistry, Biozentrum of the University of Basel, Basel, Switzerland
| | - Rui Oliveira
- REQUIMTE, Systems Biology and Engineering Group (SBE), Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
| | - Paula Marques Alves
- Instituto de Tecnologia Química e Biológica-Universidade Nova de Lisboa/Instituto de Biologia Experimental e Tecnológica, Oeiras, Portugal
- * E-mail:
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Son Y, Kim S, Choi K, Park Y, Eo S, Kim Y, Rhim B, Kim K. p35 interacts with α-tubulin and organelle proteins: Nuclear translocation of p35 in dying cells. Proteomics 2009; 9:4036-47. [DOI: 10.1002/pmic.200900122] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Bonofiglio D, Gabriele S, Aquila S, Qi H, Belmonte M, Catalano S, Andò S. Peroxisome proliferator-activated receptor gamma activates fas ligand gene promoter inducing apoptosis in human breast cancer cells. Breast Cancer Res Treat 2009; 113:423-34. [PMID: 18293083 DOI: 10.1007/s10549-008-9944-1] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2008] [Accepted: 02/12/2008] [Indexed: 10/22/2022]
Abstract
In just over a decade, apart from established metabolic actions, peroxisome proliferator-activated receptor gamma (PPARgamma) has evolved as key therapeutic target in cancer disease. Fas ligand (FasL), a trans-membrane protein, induces apoptosis by crosslinking with the Fas receptor. Despite the FasL relevance, little is available on the regulation of its expression. In the current study, we explored for the first time the potential role of PPARgamma in triggering apoptotic events through the Fas/FasL pathway in breast cancer cells. In MCF7 cells, by reverse transcription-polymerase chain reaction and Western blotting, we showed that the synthetic PPARgamma ligand rosiglitazone (BRL) enhanced FasL expression, that was abrogated by a specific PPARgamma antagonist GW9662. Transient transfection assays demonstrated that BRL transactivated human FasL promoter gene in a PPARgamma-dependent manner. Progressive 5' deletion analysis has identified a minimal promoter fragment spanning nucleotides from -318 to -237 bp, which is still sensitive to BRL treatment. FasL promoter activity was abrogated by mithramycin, suggesting an involvement of Sp1 transcription factor in PPARgamma action. Electrophoretic mobility shift and chromatin immuno-precipitation assays demonstrated that BRL increased the binding of PPARgamma and Sp1 to the Sp1 sequence located within the FasL gene promoter. The role of PPARgamma and Fas/FasL pathways in BRL-induced apoptotic events was assessed by caspase 8 cleavage in the presence of GW as well as PPARgamma and FasL RNA interferences. Our results indicate that PPARgamma positively regulates the FasL gene expression also in MDA-MB231 and in BT20, revealing a new molecular mechanism by which BRL induces apoptosis in breast cancer cells.
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Song JH, Liang CY, Chen XW. Baculovirus-mediated expression of p35 confers resistance to apoptosis in human embryo kidney 293 cells. Virol Sin 2008. [DOI: 10.1007/s12250-007-0037-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Filippova M, Johnson MM, Bautista M, Filippov V, Fodor N, Tungteakkhun SS, Williams K, Duerksen-Hughes PJ. The large and small isoforms of human papillomavirus type 16 E6 bind to and differentially affect procaspase 8 stability and activity. J Virol 2007; 81:4116-29. [PMID: 17267478 PMCID: PMC1866154 DOI: 10.1128/jvi.01924-06] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2006] [Accepted: 01/23/2007] [Indexed: 11/20/2022] Open
Abstract
Human papillomavirus type 16 (HPV-16) has developed numerous ways to modulate host-initiated immune mechanisms. The HPV-16 E6 oncoprotein, for example, can modulate the cellular level, and consequently the activity, of procaspase 8, thus modifying the cellular response to cytokines of the tumor necrosis factor family. E6 from HPV-16, but not E6 from the low-risk types 6b and 11, alters the cellular level of procaspase 8 in a dose-dependent manner. Both the large and small (E6*) isoforms of E6, which originate by way of alternate splicing, can modulate procaspase 8 stability. Intriguingly, although both isoforms bind to procaspase 8, the large isoform accelerates the degradation of procaspase 8 while the small isoform stabilizes it. Binding leads to a change in the ability of procaspase 8 to bind either to itself or to FADD (Fas-associated death domain), with the large version of E6 able to inhibit this binding while the small isoform does not. Consistent with this model, knockdown of the large version of E6 by small interfering RNA leads to increases in the levels of procaspase 8 and its binding to both itself and FADD. Thus, these alternatively spliced isoforms can modulate both the level and the activity of procaspase 8 in opposite directions.
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Affiliation(s)
- Maria Filippova
- Department of Biochemistry and Microbiology, 11085 Campus Street, 121 Mortensen Hall, Loma Linda University School of Medicine, Loma Linda, CA 92354, USA
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Abstract
Programmed cell death or apoptosis is a well regulated physiological form of cellular autodestruction. It plays an essential role in embryonic development, homeostasis, remodeling, surveillance, and host defense mechanisms. Conversely dysregulation of apoptosis, resulting in either too less or excessive cell death is implicated in pathogenesis of stroke, myocardial infarction, neurodegenerative diseases, cancer and autoimmmune disorders. Apoptosis is coordinated by a family of cysteine proteinases called caspases, which dismantle the cell by targeting panoply of proteins. The mammalian caspase family contains 14 members, a subset participates in cellular demise and the remaining are involved in the processing of pro-inflammatory cytokines. We have tried to develop a simplified picture of basic apoptotic mechanisms on the basis of recent insights into the area.
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Affiliation(s)
- Sodhi K Rupinder
- Department of Pharmaceutical Sciences and Drug Research, Punjabi University, Patiala, India.
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Inoue N, Matsuda-Minehata F, Goto Y, Sakamaki K, Manabe N. Molecular Characteristics of Porcine Fas-associated Death Domain (FADD) and Procaspase-8. J Reprod Dev 2007; 53:427-36. [PMID: 17179649 DOI: 10.1262/jrd.18136] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
To reveal the intracellular signal transduction molecules involved in granulosa cell apoptosis in porcine ovarian follicles, we cloned the porcine Fas-associated death domain (FADD), an adaptor protein for the cell death receptor, and procaspase-8, an initiator caspase. Porcine FADD (pFADD) was 636 bp (211 amino acids: aa) long and showed 74.0 and 65.4% homology with human and murine FADD, respectively. Porcine procaspase-8 (pprocaspase-8) was 1,431 bp (476 aa) long and 70.6 and 63.4% homologous with human and murine procaspase-8, respectively. To confirm the apoptosis-inducing abilities, we constructed pFADD and pprocaspase-8 cDNA expression vectors with enhanced green fluorescence protein (EGFP) and then transfected them into human uterine cervix tumor (HeLa-K), human granulosa cell-derived (KGN), murine granulosa-derived tumor (KK1), and porcine granulosa cell-derived (JC410) cells. When pFADD and pprocaspase-8 were overexpressed, cell death was induced in these transfected cells. However when caspase-inhibitor p35 was cotransfected, cell death was inhibited. The pFADD and pprocaspase-8 genes are well conserved, as are the physiological functions of their products.
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Affiliation(s)
- Naoko Inoue
- Laboratory of Animal Morphology and Function, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
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Lu M, Min T, Eliezer D, Wu H. Native chemical ligation in covalent caspase inhibition by p35. ACTA ACUST UNITED AC 2006; 13:117-22. [PMID: 16492559 DOI: 10.1016/j.chembiol.2005.12.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2005] [Revised: 11/18/2005] [Accepted: 12/19/2005] [Indexed: 11/27/2022]
Abstract
Wide-spectrum caspase inhibition by the baculoviral p35 protein was previously shown to be a consequence of covalent inhibition in which a thioester bond is stably formed between the cleavage residue Asp87 of p35 and the active site Cys360' of caspase-8. Here we show that the N-terminal fragment of cleaved p35 (p35-N) is a circular peptide when dissociated from the caspase. Biochemical and crystallographic data suggest that p35-N circularization results from the trapping of a native chemical ligation intermediate in the p35/caspase complex, in which the N-terminal Cys2 of p35 attacks the Asp87-Cys360' thioester to form an equilibrium between Asp87-Cys2 and Asp87-Cys360'. This provides a crucial covalent interaction for keeping the N terminus of p35 bound in the caspase active site, which explains the absolute requirement of Cys2 for caspase inhibition. Participation of native chemical ligation in caspase inhibition by p35 illustrates an unusual mechanism of protease inhibition.
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Affiliation(s)
- Miao Lu
- Department of Biochemistry, Weill Medical College of Cornell University, New York, New York 10021, USA
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Kitajima M, Hamazaki H, Miyano-Kurosaki N, Takaku H. Characterization of baculovirus Autographa californica multiple nuclear polyhedrosis virus infection in mammalian cells. Biochem Biophys Res Commun 2006; 343:378-84. [PMID: 16545777 DOI: 10.1016/j.bbrc.2006.02.167] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2006] [Accepted: 02/27/2006] [Indexed: 11/20/2022]
Abstract
The baculovirus Autographa californica multiple nuclear polyhedrosis virus (AcMNPV) is used as a vector in many gene therapy studies. Wild-type AcMNPV infects many mammalian cell types in vitro, but does not replicate. We investigated the dynamics of AcMNPV genomic DNA in infected mammalian cells and used flow cytometric analysis to demonstrate that recombinant baculovirus containing a cytomegalovirus immediate early promoter/enhancer with green fluorescent protein (GFP) expressed high levels of GFP in Huh-7 cells, but not B16, Raw264.7, or YAC-1 cells. The addition of butyrate, a deacetylase inhibitor, markedly enhanced the percentage of GFP-expressing Huh-7 and B16 cells, but not Raw264.7 and YAC-1 cells. The addition of 5-aza-2'-deoxycytidine, a DNA methylation inhibitor, had no enhancing effect. Polymerase chain reaction analysis using AcMNPV-gp64-specific primers indicated that AcMNPV infected not only Huh-7 and B16 cells, but also Raw264.7 and YAC-1 cells in vitro. The genomic DNA was detected in Huh-7 and B16 cells 96 h after infection. Genomic AcMNPV DNA in YAC-1 cells was not transported to the nucleus. Luciferase assay indicated that AcMNPV p35 gene mRNA and p35 promoter activity were clearly expressed only in Huh-7 and B16 cells. These results suggest that viral genomic DNA expression is restricted by different host cell factors, such as degradation, deacetylation, and inhibition of nuclear transport, depending on the mammalian cell type.
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Affiliation(s)
- Masayuki Kitajima
- Department of Life and Environmental Sciences, Chiba Institute of Technology, 2-17-1 Tsudanuma, Narashino, Chiba 275-0016, Japan
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21
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Choi SL, Choi YS, Kim YK, Sung ND, Kho CW, Park BC, Kim EM, Lee JH, Kim KM, Kim MY, Myung PK. Proteomic analysis and the antimetastatic effect ofN-(4-methyl)phenyl-O-(4-methoxy) phenyl-thionocarbamate-induced apoptosis in human melanoma SK-MEL-28 cells. Arch Pharm Res 2006; 29:224-34. [PMID: 16596996 DOI: 10.1007/bf02969398] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We employed human SK-MEL-28 cells as a model system to identify cellular proteins that accompany N-(4-methyl)phenyl-O-(4-methoxy)phenyl-thionocarbamate (MMTC)-induced apoptosis based on a proteomic approach. Cell viability tests revealed that SK-MEL-28 skin cancer cells underwent more cell death than normal HaCaT cells in a dose-dependent manner after treatment with MMTC. Two-dimensional electrophoresis in conjunction with matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry analysis or computer matching with a protein database further revealed that the MMTC-induced apoptosis is accompanied by increased levels of caspase-1, checkpoint suppressor-1, caspase-4, NF-kappaB inhibitor, AP-2, c-Jun-N-terminal kinase, melanoma inhibitor, granzyme K, G1/S specific cyclin D3, cystein rich protein, Ras-related protein Rab-37 or Ras-related protein Rab-13, and reduced levels of EMS (oncogene), ATP synthase, tyrosine-phosphatase, Cdc25c, 14-3-3 protein or specific structure of nuclear receptor. The migration suppressing effect of MMTC on SK-MEL-28 cell was tested. MMTC suppressed the metastasis of SK-MEL-8 cells. It was also identified that MMTC had little angiogenic effect because it did not suppress the proliferation of HUVEC cell line. These results suggest that MMTC is a novel chemotherapeutic and metastatic agents against the SK-MEL-28 human melanoma cell line.
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Affiliation(s)
- Su-La Choi
- Clinical Biochemistry Lab, Department of Pharmacy, College of Pharmacy, Chungnam National University, Daejon, Korea
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22
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Millet I, Wong FS, Gurr W, Wen L, Zawalich W, Green EA, Flavell RA, Sherwin RS. Targeted expression of the anti-apoptotic gene CrmA to NOD pancreatic islets protects from autoimmune diabetes. J Autoimmun 2005; 26:7-15. [PMID: 16338119 DOI: 10.1016/j.jaut.2005.10.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2005] [Revised: 10/21/2005] [Accepted: 10/25/2005] [Indexed: 11/17/2022]
Abstract
The activation of apoptosis is a critical mechanism by which pancreatic beta cells are destroyed in type 1 diabetes (T1DM). Strategies aimed at interfering with the apoptotic pathways could therefore be of potential therapeutic value. To this end, we generated NOD transgenic mice with targeted expression of the anti-apoptotic gene Cytokine response modifier A (CrmA) to pancreatic beta cells using the rat insulin promoter and the reverse tetracycline transactivator to express CrmA in a temporally controlled manner. Two lines of transgenic mice were studied whose expression of CrmA occurred only after feeding doxycycline food. Islet expression of CrmA partially protected pancreatic beta cells from the cytokine-mediated cytotoxicity in vitro and reduced modestly the spontaneous development of diabetes in NOD mice in vivo. In addition, beta cells from NOD CrmA mice were significantly protected from the destruction by diabetogenic T cells after adoptive transfer. More strikingly, NODCrmA mice were significantly resistant to the diabetogenic activity of a potent insulin-specific CD8 T-cell clone. Since these adoptive transfer models mainly represent the effector phase rather than the initiation phase of autoimmune diabetes, our data suggest that the latter is more sensitive to CrmA protection. We conclude that anti-apoptotic genes such as CrmA might be potential candidates to enhance islet graft survival in T1DM.
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Affiliation(s)
- I Millet
- Department of Internal Medicine and Immunobiology, Section of Endocrinology, Yale University School of Medicine, P.O. Box 208020, 333 Cedar Street, TAC S141, New Haven, CT 06520, USA
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23
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Nanbo A, Yoshiyama H, Takada K. Epstein-Barr virus-encoded poly(A)- RNA confers resistance to apoptosis mediated through Fas by blocking the PKR pathway in human epithelial intestine 407 cells. J Virol 2005; 79:12280-5. [PMID: 16160154 PMCID: PMC1211525 DOI: 10.1128/jvi.79.19.12280-12285.2005] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Our recent findings demonstrated that the Epstein-Barr virus-encoding small nonpolyadenylated RNA (EBER) confers resistance to various apoptotic stimuli and contributes to the maintenance of malignant phenotypes in Burkitt's lymphoma. In this study we investigated the role of EBER in the human epithelial Intestine 407 cell line, which is known to be susceptible to Fas (Apo1/CD95)-mediated apoptosis. Fas, a member of the tumor necrosis factor receptor family, transduces extracellular signals to the apoptotic cellular machinery, leading to cell death. Transfection of the EBER gene into Intestine 407 cells significantly protected the cells from Fas-mediated apoptosis, whereas EBER-negative cell lines underwent apoptosis after Fas treatment. EBER bound double-stranded RNA-dependent protein kinase R (PKR), an interferon-inducible serine/threonine kinase, and abrogated its kinase activity. Moreover, expression of the catalytically inactive dominant-negative PKR provided resistance to Fas-induced apoptosis. Expression of EBER or dominant-negative PKR also inhibited the cleavage of poly(ADP-ribose) polymerase, a mediator of the cellular response to DNA damage, downstream of the Fas-mediated apoptotic pathway. These results in combination indicate that EBER confers resistance to Fas-mediated apoptosis by blocking PKR activity in Intestine 407 cells, consistent with the idea that EBER contributes to the maintenance of epithelioid malignancies.
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Affiliation(s)
- Asuka Nanbo
- Department of Tumor Virology, Institute for Genetic Medicine, Hokkaido University, N15 W7, Kita-ku, Sapporo 060-1815, Japan
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24
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Iannello A, Debbeche O, Martin E, Attalah LH, Samarani S, Ahmad A. Viral strategies for evading antiviral cellular immune responses of the host. J Leukoc Biol 2005; 79:16-35. [PMID: 16204622 DOI: 10.1189/jlb.0705397] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The host invariably responds to infecting viruses by activating its innate immune system and mounting virus-specific humoral and cellular immune responses. These responses are aimed at controlling viral replication and eliminating the infecting virus from the host. However, viruses have evolved numerous strategies to counter and evade host's antiviral responses. Providing specific examples from the published literature, we discuss in this review article various strategies that viruses have developed to evade antiviral cellular responses of the host. Unraveling these viral strategies allows a better understanding of the host-pathogen interactions and their coevolution. This knowledge is important for identifying novel molecular targets for developing antiviral reagents. Finally, it may also help devise new knowledge-based strategies for developing antiviral vaccines.
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Affiliation(s)
- Alexandre Iannello
- Ste-Justine Hospital Research Center, Department of Microbiology and Immunology, University of Montreal, Quebec, Canada
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25
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Tamura M, Nakamura M, Ogawa Y, Toyama Y, Miura M, Okano H. Targeted expression of anti-apoptotic protein p35 in oligodendrocytes reduces delayed demyelination and functional impairment after spinal cord injury. Glia 2005; 51:312-21. [PMID: 15846791 DOI: 10.1002/glia.20212] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Functional impairment after spinal cord injury (SCI) is attributed to neuronal cell necrosis death and axonotmesis, with further worsening caused by the accompanying apoptosis of myelin-forming oligodendrocytes (OLGs). However, it is unclear as to how much OLG apoptosis contributes to functional impairment. To address this issue, we used transgenic mice characterized by the targeted expression of p35, a broad-spectrum caspase inhibitor, in OLGs using the cre/loxP system (referred to as cre/p35 transgenic mice). In this study, we examined the motor function and histopathologic changes after a contusive thoracic spinal cord injury in the cre/p35 transgenic mice. A larger number of OLGs and a lesser extent of demyelination were observed after SCI in the cre/p35 transgenic mice than in the control cre mice, which did not carry the p35 transgene. Furthermore, the motor function of the hindlimbs recovered to a significantly better degree in the cre/p35 transgenic mice than in the control cre mice. Thus, the inhibition of OLG apoptosis decreased the extent of functional impairment after SCI. These findings suggest that the inhibition of OLG apoptosis may be a potential treatment for SCI.
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Affiliation(s)
- Mutsuhiro Tamura
- Department of Orthopaedic Surgery, Keio University School of Medicine, Tokyo, Japan
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26
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Abstract
Understanding the mechanisms of the apoptotic and anti apoptotic processes may lead to a better way to control these cascades. Here we demonstrated for the first time the feasibility to express a short functional peptide in mammalian cells that abrogates the apoptosis cascade through interference with the proteolytic activity of the initiator caspase 9 and the executing caspase 3 enzymes. The expression of a short peptide that includes the pseudo-substrate motif of the apoptosis inhibitor protein P35 (Asp-Gln-Met-Asp) leads to the abrogation of cell death induced through either the mitochondrial or the death receptors pathways. Short open reading frames have been detected in several mammalian mRNAs, primarily upstream of the main long reading frame (uORFs), however, direct evidence for de-novo peptides translation has not been provided. Utilizing biochemical and imaging techniques we demonstrate here that the functional recombinant peptide was localized to the cytpoplasmic fraction of the cell. In conclusion, this work demonstrates that ribosomes recognize short ORFs to translate stable short recombinant peptides in mammalian cells. Expression of these intracellular peptides results in the knock down of apoptotic processes to generate apoptosis resistant stable cells.
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Affiliation(s)
- S Matza-Porges
- Department of Virology, The Hebrew University-Hadassah Medical School, The Hebrew University of Jerusalem, P.O. Box 12272, Jerusalem 91120, Israel
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27
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Bordi L, Castilletti C, Falasca L, Ciccosanti F, Calcaterra S, Rozera G, Di Caro A, Zaniratti S, Rinaldi A, Ippolito G, Piacentini M, Capobianchi MR. Bcl-2 inhibits the caspase-dependent apoptosis induced by SARS-CoV without affecting virus replication kinetics. Arch Virol 2005; 151:369-77. [PMID: 16155806 PMCID: PMC7086587 DOI: 10.1007/s00705-005-0632-8] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2004] [Accepted: 08/02/2005] [Indexed: 01/20/2023]
Abstract
Vero cells transfected with either neo- or bcl-2-plasmid were infected with SARS-CoV at a high multiplicity of infection. Apoptosis appeared after the onset of CPE and completion of virus replication, and could be prevented by Bcl-2 expression. Apoptosis is likely mediated by the mitochondrial pathway, as demonstrated by its inhibition using Bcl-2, and by the activation of the caspase cascade, resulting in PARP cleavage. Prevention of apoptosis did not affect susceptibility to infection, kinetics and extent of viral replication and release, thus implying that apoptosis is not involved in facilitating release and/or dissemination of SARS-CoV in Vero cells.
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Affiliation(s)
- L Bordi
- Laboratory of Virology, National Institute for Infectious Diseases INMI L. Spallanzani, Rome, Italy
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28
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Ramaswamy M, Efimova EV, Martinez O, Mulherkar NU, Singh SP, Prabhakar BS. IG20 (MADD splice variant-5), a proapoptotic protein, interacts with DR4/DR5 and enhances TRAIL-induced apoptosis by increasing recruitment of FADD and caspase-8 to the DISC. Oncogene 2005; 23:6083-94. [PMID: 15208670 DOI: 10.1038/sj.onc.1207804] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Recently, we identified Insulinoma-Glucagonoma clone 20 (IG20) that can render cells more susceptible to tumor necrosis factor-alpha (TNF-alpha)-induced apoptosis. In addition, it can slow cell proliferation, and enhance drug- and radiation-induced cell death. TNF-related apoptosis-inducing ligand (TRAIL) can selectively induce apoptosis in some cancer cells and render others susceptible to cotreatment with drugs and irradiation, with little or no effect on most normal cells. In this study, we investigated the potential of IG20 to enhance TRAIL-induced apoptosis and found that it can render cells more susceptible to TRAIL treatment through enhanced activation of caspases. Further, we showed that this effect can be suppressed by caspase inhibitors, p35 and CrmA, and a dominant-negative Fas-associated death domain-containing protein (DN-FADD). Results from colocalization and immunoprecipitation studies showed that IG20 can interact with TRAIL death receptors (DR), DR4 and DR5 and increase recruitment of FADD and caspase-8 into the TRAIL death-inducing signaling complex (DISC). These results indicate that IG20 is a novel protein that can enhance TRAIL-induced apoptosis by facilitating DISC formation.
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Affiliation(s)
- Madhu Ramaswamy
- Department of Microbiology and Immunology, University of Illinois at Chicago, 835 South Wolcott Avenue, Chicago, IL 60612, USA
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29
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Abstract
Apoptosis is a genetically programmed cell death mechanism that appears to occur in all multicellular organisms. It is a normal process that serves to maintain cellular homeostasis. However, in many diseases there is a disruption in the equilibrium between cell proliferation and cell death that contributes directly to the disease. In these cases, a possible therapeutic intervention would be to restore the skewed equilibrium by pushing it in the desired direction through the use of pharmacological agents or genetic approaches. These observations have instigated substantial research in the field of apoptosis, resulting in an increasingly detailed analysis of the molecular mechanisms and the sequence of events that occur in this cell death pathway. In addition, by trying to understand this pathway, several potential therapeutic agents have arisen from those used in chemo-, radio-, and cytokine therapy. While these agents have been relatively successful, it is rare that their effect is complete. Thus, the search continues for a strategy to conquer those cells that are resistant to these regimens. Genetic approaches are novel and have been shown to be quite successful in several in vitro and animal models. They also tend to have low toxicity. It is believed that using a more traditional front-line approach of therapy, supplemented by appropriate genetic intervention, will allow substantial increases in the efficacy of treatment, while at the same time introducing little or no additional toxicity.
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Affiliation(s)
- S C Dixon
- Medicine Branch, Clinical Pharmacokinetics Unit, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
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30
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Gillet L, Vanderplasschen A. Viral Subversion of the Immune System. Applications of Gene-Based Technologies for Improving Animal Production and Health in Developing Countries 2005. [PMCID: PMC7121541 DOI: 10.1007/1-4020-3312-5_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The continuous interactions between host and viruses during their co-evolution have shaped not only the immune system but also the countermeasures used by viruses. Studies in the last decade have described the diverse arrays of pathways and molecular targets that are used by viruses to elude immune detection or destruction, or both. These include targeting of pathways for major histocompatibility complex class I and class II antigen presentation, natural killer cell recognition, apoptosis, cytokine signalling, and complement activation. This paper provides an overview of the viral immune-evasion mechanisms described to date. It highlights the contribution of this field to our understanding of the immune system, and the importance of understanding this aspect of the biology of viral infection to develop efficacious and safe vaccines.
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31
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Yu D, Khan E, Khaleque MA, Lee J, Laco G, Kohlhagen G, Kharbanda S, Cheng YC, Pommier Y, Bharti A. Phosphorylation of DNA topoisomerase I by the c-Abl tyrosine kinase confers camptothecin sensitivity. J Biol Chem 2004; 279:51851-61. [PMID: 15448168 DOI: 10.1074/jbc.m404396200] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
DNA topoisomerase I (topo I) is involved in the regulation of DNA supercoiling, gene transcription, recombination, and DNA repair. The anticancer agent camptothecin specifically targets topo I. The mechanisms responsible for the regulation of topo I in cells, however, are not known. This study demonstrates that c-Abl-dependent phosphorylation up-regulates topo I activity. The c-Abl SH3 domain bound directly to the N-terminal region of topo I. The results demonstrate that c-Abl phosphorylated topo I at Tyr268 in core subdomain II. c-Abl-mediated phosphorylation of topo I Tyr268 in vitro and in cells conferred activation of the topo I isomerase function. Moreover, activation of c-Abl by treatment of cells with ionizing radiation was associated with c-Abl-dependent phosphorylation of topo I and induction of topo I activity. The functional significance of the c-Abl/topo I interaction is supported by the findings that (i) mutant topo I(Y268F) exhibited loss of c-Abl-induced topo I activity, and (ii) c-Abl-/- cells were deficient in the accumulation of protein-linked DNA breaks. In addition, loss of topo I phosphorylation in c-Abl-deficient cells conferred resistance to camptothecin-induced apoptosis. These findings collectively support a model in which c-Abl-mediated phosphorylation of topo I is functionally important to topo I activity and sensitivity to topo I poisons.
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Affiliation(s)
- Donghui Yu
- Department of Adult Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02115, USA
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32
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Affiliation(s)
- A Müllbacher
- Division of Immunology and Genetics, John Curtin School of Medical Research, Australian National University, P.O. Box 334, Canberra, ACT 2601, Australia.
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33
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Sawada M, Kiyono T, Nakashima S, Shinoda J, Naganawa T, Hara S, Iwama T, Sakai N. Molecular mechanisms of TNF-α-induced ceramide formation in human glioma cells:P53-mediated oxidant stress-dependent and -independent pathways. Cell Death Differ 2004; 11:997-1008. [PMID: 15131591 DOI: 10.1038/sj.cdd.4401438] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The present study was designed to examine the roles of p53, reactive oxygen species (ROS), and ceramide, and to determine their mutual relationships during tumor necrosis factor (TNF)-alpha-induced apoptosis of human glioma cells. In cells possessing wild-type p53, TNF-alpha stimulated ceramide formation via the activation of both neutral and acid sphingomyelinases (SMases), accompanied by superoxide anion (O2-*) production, and induced mitochondrial depolarization and cytochrome c release, whereas p53-deficient cells were partially resistant to TNF-alpha and lacked O2-* generation and neutral SMase activation. Restoration of functional p53 sensitized glioma cells expressing mutant p53 to TNF-alpha by accumulation of O2-*. z-IETD-fmk (benzyloxycarbonyl-Ile-Glu-Thr-Asp fluoromethyl ketone), but not z-DEVD-fmk (benzyloxycarbonyl-Asp-Glu-Val-Asp fluoromethyl ketone), blocked TNF-alpha-induced ceramide formation through both SMases as well as O2-* generation. Caspase-8 was processed by TNF-alpha regardless of p53 status of cells or the presence of antioxidants. Two separate signaling cascades, p53-mediated ROS-dependent and -independent pathways, both of which are initiated by caspase-8 activation, thus contribute to ceramide formation in TNF-alpha-induced apoptosis of human glioma cells.
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Affiliation(s)
- M Sawada
- Department of Neurosurgery, Gifu University School of Medicine, Tsukasamachi-40, Gifu 500-8705, Japan.
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Abstract
The regulation of cell death has been investigated in a number of clinical disorders including renal ischemic and toxic acute renal failure. Caspases play a crucial role in the execution or final phase of cell death by cleaving and inactivating various structural and functional intracellular proteins that are essential for cell survival and proliferation. Evidence is now emerging to implicate the caspase pathway in a variety of renal diseases including the pathogenesis of acute renal failure. Among the 14 known members of the caspase family thus far identified several executioner caspases including caspases-3, -6, and -7 and the proinflammatory caspase including caspase-1 may participate in the final degradation of intracellular proteins. The activation of these caspases is regulated by the receptor- and mitochondrial-mediated cell signaling pathways as well as by the endoplasmic reticulum stress response. While the role of some caspases in renal injury is emerging, the roles of various proinflammatory and other executioner caspases remain to be determined. Although many pro- and anti-apoptotic molecules that act upstream of caspase activation have been identified, their regulation is yet to be determined in the pathogenesis of renal injury. A precise description of caspase-mediated cell death pathway and regulation of caspase activation is, therefore, critical to the understanding of the mechanism of renal injury and to the development of therapeutic targets that prevent renal diseases and preserve renal function.
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Affiliation(s)
- Gur P Kaushal
- Department of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
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35
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Abstract
Granzyme B (GrB) is a serine protease that is released by cytotoxic lymphocytes to kill virus-infected and tumor cells. Recent advances in the understanding of GrB have stressed the importance of reassessing the mechanisms by which GrB accomplishes its death functions. These include the uptake and trafficking of GrB within target cells, pathways used to trigger cell death, and the mechanism(s) controlling its killing activity. In addition, the role that GrB plays in human pathologies is still to be defined. The purpose of this review is to discuss recent insights into the biology of GrB and to evaluate its functional significance in health and disease.
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Affiliation(s)
- Felipe Andrade
- Department of Immunology and Rheumatology, Instituto Nacional de Ciencias Médicas y Nutrición 'Salvador Zubirán', Mexico City, Mexico
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36
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Affiliation(s)
- M Barry
- Department of Medical Microbiology and Immunology, University of Alberta, 671 Heritage Medical Research Center, Edmonton, Alberta, T6G 252 Canada.
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37
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Abstract
Apoptosis, known as programmed cell death, is a conserved, gene-directed mechanism for the elimination of unnecessary or unwanted cells from an organism. A retrospective look at the basis of human disease pathogenesis almost always reveals an apoptotic component that either contributes to disease progression or accounts for it. Modulating the expression of key molecular components of the cell death machinery is an attractive and obvious strategy for apoptosis-based therapeutics. Apoptosis is an important component of most developmental abnormalities and human diseases and in many cases the underlying cause of the resulting pathology. It has also become clear that many, if not all, viruses possess mechanisms to forestall apoptosis and provide a living host to enhance virus propagation. Diseases like AIDS involve excessive apoptosis, and suppression of apoptosis may restore functionality to the infected tissues. Although these are still early days, it is difficult not to get excited about the significant advances that have already been made. The true therapeutic benefits of apoptosis modulation for the treatment of many devastating human diseases remain to be discovered.
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Affiliation(s)
- Zodwa Dlamini
- Genetics and Developmental Biology Division, School of Molecular and Cell Biology, University of Witwatersrand, Private Bag 3, 2050, Johannesburg, South Africa.
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38
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Aparna G, Bhuyan AK, Sahdev S, Hasnain SE, Kaufman RJ, Ramaiah KVA. Stress-Induced Apoptosis in Spodoptera frugiperda (Sf9) Cells: Baculovirus p35 Mitigates eIF2α Phosphorylation. Biochemistry 2003; 42:15352-60. [PMID: 14690445 DOI: 10.1021/bi0349423] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Spodoptera frugiperda (Sf9) ovarian cells, natural hosts for baculovirus, are good model systems to study apoptosis and also heterologous gene expression. We report that uninfected Sf9 cells readily undergo apoptosis and show increased phosphorylation of the alpha subunit of eukaryotic initiation factor 2 (eIF2alpha) in the presence of agents such as UVB light, etoposide, high concentrations of cycloheximide, and EGTA. In contrast, tunicamycin, A23187, and low concentrations of cycloheximide promoted eIF2alpha phosphorylation in Sf9 cells but without apoptosis. These findings therefore suggest that increased eIF2alpha phosphorylation does not always necessarily lead to apoptosis, but it is a characteristic hallmark of stressed cells and also of cells undergoing apoptosis. Cell death induced by the above agents was abrogated by infection of Sf9 cells with wild-type (wt) AcNPV. In contrast, Sf9 cells when infected with vAcdelta35, a virus carrying deletion of the antiapoptotic p35 gene, showed increased apoptosis and enhanced eIF2alpha phosphorylation. Further, a recombinant wt virus vAcS51D expressing human S51D, a phosphomimetic form of eIF2alpha, induced apoptosis in UVB pretreated Sf9 cells. However, infection with vAcS51A expressing a nonphosphorylatable form (S51A) of human eIF2alpha partially reduced apoptosis. Consistent with these findings, it has been observed here that caspase activation has led to increased eIF2alpha phosphorylation, while caspase inhibition by z-VAD-fmk reduced eIF2alpha phosphorylation selectively in cells exposed to proapoptotic agents. These findings therefore suggest that the stress signaling pathway determines apoptosis, and caspase activation is a prerequisite for increased eIF2alpha phosphorylation in Sf9 cells undergoing apoptosis. The findings also reinforce the conclusion for the first time that the "pancaspase inhibitor" baculovirus p35 mitigates eIF2alpha phosphorylation.
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Affiliation(s)
- Gunda Aparna
- Department of Biochemistry, University of Hyderabad, Hyderabad 500 046, India
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39
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Abstract
Oxidative stress is thought to be a major contributor to the progress of the Parkinson's Disease (PD) because of the high vulnerability of dopaminergic cells against oxidative stress. The present work demonstrates that with the expression of the baculovirus p35 gene, PC12 cells could gain a high resistance against oxidative toxicants, hydrogen peroxide (H(2)O(2)) and 6-hydroxydopamine (6-OHDA). The DNA fragmentation analysis showed that PC12 cells underwent apoptosis after exposure to H(2)O(2) or 6-OHDA, while PP35 cells, a p35-expressing PC12 cell line, did not. Flow cytometric analysis showed that treatment with 150 microM H(2)O(2) or 120 microM 6-OHDA for 24 h caused 52.86% or 66.36% apoptotic cell, respectively, in PC 12 cells, but only 4.26% or 5.80% in PP35 cells. The cell viability measured by 3-(4,5-dimethylthiazal-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay indicated that H(2)O(2) and 6-OHDA induced a dose-dependent cell death on PC12 cells that were greatly remitted on PP35 cells. The viability of PP35 cells was even stronger than that of PC12 cells protected by glial cell line deprived neurotrophic factor (GDNF). The surviving PP35 cells remained normal cell morphology and showed positive with tyrosine hydroxylase (TH) immunocytochemical staining. These results indicate that baculovirus p35 gene possesses remarkable ability to rescue PC12 cells from death in experimental paradigms associated with oxidative stress.
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Affiliation(s)
- Ming Zhuo
- Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue Yang Road, 200031, Shanghai, PR China
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40
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Abstract
Both vaccinated and unvaccinated women during pregnancy who contract variola virus, the causative agent of smallpox, suffer much higher mortality rates than nonpregnants. Furthermore, acute maternal smallpox leads to spontaneous abortion, premature termination of pregnancy and early postnatal infant mortality. The mechanisms governing the abortifacient activity of smallpox, as well as the enhanced susceptibility of gestating women to lethal disease, have remained largely unexamined. Experimental poxvirus infections in nonpregnant small animal models have revealed that T helper type 1 (TH1) cytokines promote efficient resolution of these infections whereas type 2 (TH2) cytokines enhance viral pathogenesis. These data, combined with recent understanding of how the immune system is modulated by pregnancy, may offer important clues as to the increased pathogenesis of variola in pregnant women. The aim of this review is to bring together the current literature on the effects of poxvirus infections in nonpregnant hosts, as well as the effects of pregnancy on the immune system, in order to develop unifying concepts that may provide insight into the pathogenesis of variola during pregnancy and why prior vaccination with vaccinia virus the live anti-variola vaccine offers less protection to pregnant women and their unborn children.
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Affiliation(s)
- Daniel E Hassett
- The Scripps Research Institute CVN-9, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
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41
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Devadas S, Hinshaw JA, Zaritskaya L, Williams MS. Fas-stimulated generation of reactive oxygen species or exogenous oxidative stress sensitize cells to Fas-mediated apoptosis. Free Radic Biol Med 2003; 35:648-61. [PMID: 12957657 DOI: 10.1016/s0891-5849(03)00391-5] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Inhibition of Fas-mediated apoptosis in B cell lymphomas by thiol antioxidants (glutathione and N-acetylcysteine) supported previous studies, suggesting that Fas-stimulated ROS generation may play a role in Fas-mediated apoptosis. Thus, the goal of the current study was to determine if Fas stimulation could induce ROS generation and what role, if any, it played in apoptosis. Fas crosslinking induced rapid generation of ROS (within 15 min) well before the appearance of characteristic apoptotic changes. Overexpression of catalase or superoxide dismutase suggested that Fas induced production of both superoxide anion and hydrogen peroxide. ROS generation was only observed, however, in cells that were sensitive to apoptosis and not in B cells inherently resistant to anti-Fas or in those in which resistance was induced by B cell receptor crosslinking. The exogenous addition of 250 microM hydrogen peroxide could reverse the resistant phenotype and sensitize cells to Fas-induced apoptosis. In Fas-sensitive cells, depletion of endogenous antioxidant defenses with buthionine sulfoximine increased the sensitivity to Fas-induced apoptosis, while overexpression of antioxidant enzymes and antiapoptotic proteins suggested a role for Fas-induced production of hydrogen peroxide in apoptosis. Further analysis suggested a redox-sensitive step early in Fas signaling at the level of initiator caspase (caspase-8) activation. Thus, the data suggest that the level of oxidative stress, either from exogenous sources or generated endogenously upon receptor stimulation, regulates the sensitivity to Fas-mediated apoptosis.
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Affiliation(s)
- Satish Devadas
- Immunology Department, American Red Cross Biomedical Research and Development, Rockville, MD 20855, USA
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42
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Abstract
Apoptosis, an active mechanism of cell death, is of central importance in many biological scenarios. Research in this area has the potential to contribute to our understanding of many diseases and raises several potential therapeutic opportunities. Given this potential and the speed with which our understanding of this field has advanced over recent years, it is timely to introduce the clinician to the background on which the clinical implications of this research will be built. This review begins with contrasting apoptosis with the other mechanism of cell death, necrosis, and then outlines the features by which apoptosis may be recognised. With a view to understanding the level at which this process may be involved in disease and therapeutics, it is important to be aware of the basic mechanistic features of the induction and execution of apoptosis. In this, surface molecules such as CD95 (Fas) and the cascade of intracellular enzymes involved at many levels in apoptosis, the caspases, are of central importance. In all this, the mitochondrion is crucial to the induction of apoptosis and the regulation of the whole process. In the last part of this review, we attempt to draw out the clinical relevance of all this information. It is clear that apoptosis has an important role in the pathophysiology of malignancy, particularly with respect to haematological cancers, but also other oncological diseases. Apoptosis is also very important in autoimmune disease and viral infection. Finally, it is clear that apoptosis may be manipulated therapeutically to the benefit of patients in various scenarios. This is clearly an exciting area for future development, but one which clearly depends on a thorough mechanistic understanding.
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MESH Headings
- Antibodies, Monoclonal/therapeutic use
- Antibodies, Monoclonal, Murine-Derived
- Antineoplastic Agents/therapeutic use
- Apoptosis/drug effects
- Apoptosis/genetics
- Apoptosis/physiology
- Calorimetry
- Caspases/analysis
- Caspases/metabolism
- Cell Death/physiology
- Cell Transformation, Neoplastic
- Cytokines/physiology
- Drug Resistance, Neoplasm
- Flow Cytometry
- Forecasting
- Genes, bcl-2
- Humans
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug therapy
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/pathology
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/physiopathology
- Mitochondria/physiology
- Necrosis
- Neoplasms/drug therapy
- Neoplasms/pathology
- Neoplasms/physiopathology
- Phagocytosis
- Research
- Rituximab
- Spectrophotometry
- fas Receptor
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Affiliation(s)
- Faris Q Alenzi
- Clinical Laboratory Science, School of Medicine and Medical Sciences, King Faisal University, Dammam, Saudi Arabia
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43
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Abstract
Tumor necrosis factor (TNF)-related cytokines are critical effector molecules in the immune response to viral pathogens. Engagement of the TNF receptors by their cognate ligands activates apoptotic and non-apoptotic signaling pathways, both of which can mediate antiviral activity. In response, viruses have evolved mechanisms to inhibit signaling by some cytokines of the TNF superfamily. These strategies are largely unique to each class of virus, but are similar in that they all target key regulatory checkpoints of the TNF pathway. In recent years, studies directed towards dissecting the mechanisms of TNF signaling and the viral retort have led to several significant discoveries, and form the basis for this review.
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Affiliation(s)
- Chris A Benedict
- Division of Molecular Immunology, La Jolla Institute for Allergy and Immunology, 10355 Science Center Drive, San Diego, CA 92121, USA.
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44
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Takarada S, Imanishi T, Hano T, Nishio I. Oxidized low-density lipoprotein sensitizes human vascular smooth muscle cells to FAS (CD95)-mediated apoptosis. Clin Exp Pharmacol Physiol 2003; 30:289-94. [PMID: 12680849 DOI: 10.1046/j.1440-1681.2003.03829.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
1. It was investigated in the present study whether oxidized low-density lipoprotein (oxLDL) was implicated in the susceptibility of human vascular smooth muscle cells (VSMC) to Fas-mediated death. Human fetal aorta smooth muscle cells were treated with agonistic anti-Fas antibody (CH11) and oxLDL and cell death was then determined by viability and DNA fragmentation. 2. The results of the present study show that cross-linking of Fas receptor with anti-Fas antibody in the presence of oxLDL induced death and DNA fragmentation in human VSMC, which were blocked by the caspase inhibitor z-VAD.fmk, followed by the upregulation of cell surface Fas. 3. The data indicate that oxLDL is implicated in death in VSMC and provide evidence that oxLDL is involved in Fas signal transduction. The present study proposes a novel mechanism(s) by which VSMC become susceptible to Fas ligand. 4. One of the mechanisms proposed by which oxLDL upregulates cell surface Fas is by inhibiting the degradation of Fas through the ubiquitin-proteasome pathway.
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MESH Headings
- Amino Acid Chloromethyl Ketones/pharmacology
- Antibodies/pharmacology
- Aorta/cytology
- Apoptosis/drug effects
- Apoptosis/physiology
- Caspase Inhibitors
- Cells, Cultured
- Cysteine Endopeptidases/physiology
- DNA Fragmentation/drug effects
- Embryo, Mammalian
- Enzyme-Linked Immunosorbent Assay
- Humans
- Leupeptins/pharmacology
- Lipoproteins, LDL/pharmacology
- Lipoproteins, LDL/physiology
- Multienzyme Complexes/antagonists & inhibitors
- Multienzyme Complexes/physiology
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Proteasome Endopeptidase Complex
- Up-Regulation
- fas Receptor/biosynthesis
- fas Receptor/drug effects
- fas Receptor/immunology
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Affiliation(s)
- Shigeho Takarada
- Department of Cardiovascular Medicine, Wakayama Medical University, Japan
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45
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Fan H, Walters CS, Dunston GM, Tackey R. IL-12 plays a significant role in the apoptosis of human T cells in the absence of antigenic stimulation. Cytokine 2003; 19:126-37. [PMID: 12242079 DOI: 10.1006/cyto.2002.1958] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Interleukin-12 (IL-12) is an immunoregulatory cytokine that plays an essential role in cell-mediated immunity. It is known to induce T cell apoptosis in in vivo systems such as graft-versus-host disease (GVHD) and experimental autoimmune uveitis (EAU). However, the role of IL-12 in T cell apoptosis in the absence of antigenic stimulation has not been clearly defined. This study was conducted to investigate whether IL-12, in the absence of an antigen, is able to induce T cell apoptosis, and also, which signalling pathways utilized by IL-12 are involved in this process. Our data clearly showed that IL-12 in the absence of an antigen induces apoptosis in T cells. Flow cytometry and ELISA showed FasL up-regulation and increased IFN-gamma synthesis in IL-12 treated T cells, while Fas and TNF-R1 showed little change. Semi-quantitative RT-PCR demonstrated that IL-12 was able to up-regulate TNF-alpha and FasL mRNA expression. Furthermore, IL-12 induced apoptosis was associated with caspase-3, caspase-2, caspase-7, DNA fragmentation factor 45 (DFF45) and Fas associated death domain (FADD) whereas TNF receptor associated death domain (TRADD) and receptor interacting protein (RIP) were not. Inhibition of Janus tyrosine kinase (JAK) was able to suppress IL-12 induced T cell apoptosis. Anti-FasL antibody was able to block IL-12 induced T cell apoptosis. In conclusion, our findings suggest that IL-12 is able to induce T cell apoptosis in the absence of an antigen. In addition, the present data suggest that this process is FasL mediated and caspase-3 dependent. Furthermore, JAK was shown to be involved in this process. These results may have significant implications in the understanding of IL-12 mediated T cell apoptosis.
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Affiliation(s)
- Hongtao Fan
- Department of Medicine, Howard University, Washington, DC, USA
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46
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Xu G, Rich RL, Steegborn C, Min T, Huang Y, Myszka DG, Wu H. Mutational analyses of the p35-caspase interaction. A bowstring kinetic model of caspase inhibition by p35. J Biol Chem 2003; 278:5455-61. [PMID: 12458208 DOI: 10.1074/jbc.m211607200] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Apoptosis is a highly regulated multistep process for programmed cellular destruction. It is centered on the activation of a group of intracellular cysteine proteases known as caspases. The baculoviral p35 protein effectively blocks apoptosis through its broad spectrum caspase inhibition. It harbors a caspase recognition sequence within a highly protruding reactive site loop (RSL), which gets cleaved by a target caspase before the formation of a tight complex. The crystal structure of the post-cleavage complex between p35 and caspase-8 shows that p35 forms a thioester bond with the active site cysteine of the caspase. The covalent bond is prevented from hydrolysis by the N terminus of p35, which repositions into the active site of the caspase to eliminate solvent accessibility of the catalytic residues. Here, we report mutational analyses of the pre-cleavage and post-cleavage p35/caspase interactions using surface plasmon resonance biosensor measurements, pull-down assays and kinetic inhibition experiments. The experiments identify important structural elements for caspase inhibition by p35, including the strict requirement for a Cys at the N terminus of p35 and the rigidity of the RSL. A bowstring kinetic model for p35 function is derived in which the tension generated in the bowstring system during the pre-cleavage interaction is crucial for the fast post-cleavage conformational changes required for inhibition.
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Affiliation(s)
- Guozhou Xu
- Department of Biochemistry, Weill Medical College of Cornell University, New York, New York 10021, USA
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47
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Tomioka M, Shirotani K, Iwata N, Lee HJ, Yang F, Cole GM, Seyama Y, Saido TC. In vivo role of caspases in excitotoxic neuronal death: generation and analysis of transgenic mice expressing baculoviral caspase inhibitor, p35, in postnatal neurons. Brain Res Mol Brain Res 2002; 108:18-32. [PMID: 12480175 DOI: 10.1016/s0169-328x(02)00486-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Caspases, a family of cysteine proteases, are thought to be critical mediators of apoptosis. To examine the role of neuronal caspases in excitotoxic neurodegeneration in vivo, we have generated transgenic mice expressing the baculovirus protein p35, a potent viral caspase inhibitor, using the neuron-specific calmodulin dependent kinase-II alpha (CaMKII-alpha) promoter. The expression of p35 was confirmed by reverse transcriptase-polymerase chain reaction (RT-PCR), Western blotting and immunohistochemistry. We analyzed caspase activation and cell death by employing an experimental paradigm, in which the excitotoxin kainate (KA) was injected into CA1 of hippocampus and the distribution of the caspase-generated actin fragment was detected immunohistochemically. While kainate treatment led to selective neuronal death in the CA1, CA3 and CA4 of non-transgenic control mice, we observed restricted caspase activation only in the CA3 sector. The transgenic expression of p35 consistently inhibited the kainate-induced caspase activation, but failed to influence the death of neurons to any extent. In addition, we observed concomitant early calpain activation in the specific areas where neurons underwent degeneration in both the transgenic and non-transgenic mice. These results indicate that p35-inhibitable caspases play rather minor roles in the kainate-induced excitotoxicity and that the relative contribution of calpain is likely to be greater than that of caspases.
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Affiliation(s)
- Masanori Tomioka
- Laboratory for Proteolytic Neuroscience, Brain Science Institute, RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
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48
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Jabbour AM, Ekert PG, Coulson EJ, Knight MJ, Ashley DM, Hawkins CJ. The p35 relative, p49, inhibits mammalian and Drosophila caspases including DRONC and protects against apoptosis. Cell Death Differ 2002; 9:1311-20. [PMID: 12478468 DOI: 10.1038/sj.cdd.4401135] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2002] [Revised: 08/07/2002] [Accepted: 08/20/2002] [Indexed: 11/08/2022] Open
Abstract
This study characterized the ability of a new member of the p35 family, p49, to inhibit a number of mammalian and insect caspases. p49 blocked apoptosis triggered by treatment with Fas ligand (FasL), Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) or ultraviolet (UV) radiation but provided negligible protection against apoptosis induced by the chemotherapeutic drug cisplatin. The caspase cleavage site in p49 was determined, and mutation of the P1 residue of this site abolished the ability of p49 to inhibit caspases, implying that p49 inhibits caspases through an analogous suicide-substrate mechanism to p35. Unlike p35, p49 inhibited the upstream insect caspase DRONC.
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Affiliation(s)
- A M Jabbour
- Department of Haematology and Oncology, Royal Children's Hospital, Parkville 3052, Australia
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49
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Abstract
The signaling networks that mediate activation, proliferation, or programmed cell death of T lymphocytes are dependent on complex redox and metabolic pathways. T lymphocytes are primarily activated through the T-cell receptor and co-stimulatory molecules. Although activation results in lymphokine production, proliferation, and clonal expansion, it also increases susceptibility to apoptosis upon crosslinking of cell-surface death receptors or exposure to toxic metabolites. Activation signals are transmitted by receptor-associated protein tyrosine kinases and phosphatases through calcium mobilization to a secondary cascade of kinases, which in turn activate transcription factors initiating cell proliferation and cytokine production. Initiation and activity of cell death-mediating proteases are redox-sensitive and dependent on energy provided by ATP. Mitochondria play crucial roles in providing ATP for T-cell activation through the electron transport chain and oxidative phosphorylation. The mitochondrial transmembrane potential (DeltaPsi(m)) plays a decisive role not only by driving ATP synthesis, but also by controlling reactive oxygen species production and release of cell death-inducing factors. DeltaPsi(m) and reactive oxygen species levels are regulated by the supply of reducing equivalents, glutathione and thioredoxin, as well as NADPH generated in the pentose phosphate pathway. This article identifies redox and metabolic checkpoints controlling activation and survival of T lymphocytes.
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Affiliation(s)
- Andras Perl
- Departments of Medicine, Microbiology and Immunology, and Pathology, State University of New York Upstate Medical University, College of Medicine, 750 East Adams Street, Syracuse, NY 13210, USA.
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50
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Otsuka M, Kato N, Taniguchi H, Yoshida H, Goto T, Shiratori Y, Omata M. Hepatitis C virus core protein inhibits apoptosis via enhanced Bcl-xL expression. Virology 2002; 296:84-93. [PMID: 12036320 DOI: 10.1006/viro.2002.1371] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Previous studies indicated that hepatitis C virus core protein influences cellular apoptosis. However, the precise mechanisms of the effects are not fully understood. Therefore, in this study, we examined the mechanisms of the effects on cell apoptosis by core protein, using transiently transfected and magnetically collected core-producing HepG2 cells. First, to elucidate the target site of core protein in the apoptotic pathway, we examined the activation of caspases after anti-Fas antibody stimulation. Core protein inhibited the apoptotic cascade downstream from caspase 8 and upstream from caspase 3. Next, to clarify more direct mechanisms of this effect, mRNA levels of several bcl-2-related genes were examined. An RNase protection assay showed that the mRNA of bcl-xl increased in the core-producing cells. We showed that this increase was mediated by the enhancement of bcl-x promoter activity by core protein through an extracellular-regulated kinase pathway. These results suggest that core protein inhibits apoptosis at the mitochondria level through augmentation of Bcl-x expression, resulting in an inhibition of caspase 3 activation.
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Affiliation(s)
- Motoyuki Otsuka
- Department of Gastroenterology, University of Tokyo, Tokyo, Japan
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