scholarly journals Fas and tumor necrosis factor receptor-mediated cell death: similarities and distinctions.

1994 ◽  
Vol 180 (2) ◽  
pp. 557-567 ◽  
Author(s):  
M V Clement ◽  
I Stamenkovic

Fas antigen and two tumor necrosis factor receptors (TNFR), p55 and p75, are implicated in the triggering of cell death upon stimulation by natural ligands and specific monoclonal antibodies. However, the relative efficiency of each receptor, the mechanisms that regulate their function and the signaling pathways they employ, remain to be elucidated. In this study, fusion proteins, composed of the extracellular domain of CD40 and the intracellular and transmembrane domains of Fas, TNFRp55 and TNFRp75, were stably expressed in a human melanoma cell line that is deficient in Fas and TNFR expression. Transfectants were stimulated by a soluble recombinant form of the CD40 ligand gp39, and the effect on cell viability determined. Engagement of all three fusion proteins by the gp39 ligand induced lethal signals, but the rate at which cell death occurred was distinct. Fas-derived signals were observed to have the most rapid effect, killing most cells within hours of stimulation, whereas TNFRp55- and TNFRp75-associated signals resulted in cell death within 2-3 d after engagement by ligand. It is interesting to note that optimal cell killing by all three fusion proteins was dependent on a critical, low to intermediate, cell surface expression level. High levels of fusion protein expression, on the other hand, were associated with inhibition of cell death. Our results provide a model to study Fas and TNFR-mediated cell death and suggest a novel mechanism for the regulation of death signals triggered by members of the TNFR family.

2007 ◽  
Vol 58 (1) ◽  
pp. 273-283 ◽  
Author(s):  
Belinda Nedjai ◽  
Graham A. Hitman ◽  
Nasim Yousaf ◽  
Yuti Chernajovsky ◽  
Susanna Stjernberg-Salmela ◽  
...  

1996 ◽  
Vol 183 (2) ◽  
pp. 669-674 ◽  
Author(s):  
S Y Lee ◽  
C G Park ◽  
Y Choi

CD30 is a member of the tumor necrosis factor superfamily and a surface marker for Hodgkin's disease. Normal activated T cells and several virally transformed T or B cell lines also show CD30 expression. The interaction of CD30 with its ligand induces cell death or proliferation, depending on the cell type. In this report we characterize the signals mediated by the intracellular domain of CD30 and show that, in combination with signal(s) transduced by the T cell receptor, the multimerization of CD30 cytoplasmic domain induces Fas(CD95)-independent cell death in T cell hybridomas. Deletion analysis shows that the COOH-terminal 66 amino acids of CD30 are required to induce cell death. Using the yeast two-hybrid system, we have identified that the same region of CD30 interacts with tumor necrosis factor receptor-associated factor (TRAF)1 and TRAF2. These results indicate that TRAF1 and/or TRAF2 play an important role in cell death in addition to their previously identified roles in cell proliferation.


2003 ◽  
Vol 77 (12) ◽  
pp. 6700-6708 ◽  
Author(s):  
Yida Yang ◽  
Ilia Tikhonov ◽  
Tracy J. Ruckwardt ◽  
Mahmoud Djavani ◽  
Juan Carlos Zapata ◽  
...  

ABSTRACT The human immunodeficiency virus (HIV) Tat protein has a critical role in viral transcription, but this study focuses on its additional role as an extracellular effector of lymphocyte cell death. It is well known that Tat induces tumor necrosis factor-related apoptosis-induced ligand (TRAIL) in peripheral blood mononuclear cells (PBMC), and we show that the majority of TRAIL is produced by the monocyte subset of PBMC. Human monocytes and U937 monoblastoid cells did not take up soluble HIV Tat-86, as T cells did, yet produced more TRAIL than did T cells. TRAIL secretion was induced by Tat and by a cysteine-rich peptide of Tat but not by sulfhydryl-modified Tat toxoid. Although there was only a slight increase in cell surface expression of TRAIL on monocytes, sufficient TRAIL was secreted to be toxic for T cells. The cytotoxicity of Tat-stimulated monocyte medium could be blocked by a TRAIL-neutralizing antibody. T cells treated with Tat did not secrete enough TRAIL to mediate cell death in our assay. Remarkably, uninfected T cells are more susceptible to TRAIL than are HIV-infected T cells. The production of TRAIL by Tat-stimulated monocytes provides a mechanism by which HIV infection can destroy uninfected bystander cells.


2008 ◽  
Vol 283 (50) ◽  
pp. 34954-34965 ◽  
Author(s):  
Anne-Laure Mahul-Mellier ◽  
Flavie Strappazzon ◽  
Anne Petiot ◽  
Christine Chatellard-Causse ◽  
Sakina Torch ◽  
...  

Blood ◽  
1999 ◽  
Vol 93 (7) ◽  
pp. 2173-2185 ◽  
Author(s):  
Masud H. Khandaker ◽  
Gordon Mitchell ◽  
Luoling Xu ◽  
Joseph D. Andrews ◽  
Rajkumari Singh ◽  
...  

The neutrophil-specific G-protein–coupled chemokine receptors, CXCR1 and CXCR2, bind with high affinity to the potent chemoattractant interleukin-8 (IL-8). The mechanisms of IL-8 receptor regulation are not well defined, although previous studies have suggested a process of ligand-promoted internalization as a putative regulatory pathway. Herein, we provide evidence for two distinct processes of CXCR1 and CXCR2 regulation. Confocal microscopy data showed a redistribution of CXCR1 expression from the cell surface of neutrophils to internal compartments after stimulation with IL-8, whereas stimulation with bacterial lipopolysaccharide (LPS) or tumor necrosis factor- (TNF-) did not induce CXCR1 internalization but instead mediated a significant loss of membrane-proximal CXCR1 staining intensity. To investigate whether proteolytic cleavage was the mechanism responsible for LPS- and TNF-–induced downmodulation of IL-8 receptors, we tested a panel of proteinase inhibitors. The downmodulation of CXCR1 and CXCR2 by LPS and TNF- was most dramatically inhibited by metalloproteinase inhibitors; 1,10-phenanthroline and EDTA significantly attenuated LPS- and TNF-–induced loss of CXCR1 and CXCR2 cell surface expression. Metalloproteinase inhibitors also blocked the release of CXCR1 cleavage fragments into the cell supernatants of LPS- and TNF-–stimulated neutrophils. In addition, while treatment of neutrophils with LPS and TNF- inhibited IL-8 receptor–mediated calcium mobilization and IL-8–directed neutrophil chemotaxis, both 1,10-phenanthroline and EDTA blocked these inhibitory processes. In contrast, metalloproteinase inhibitors did not affect IL-8–mediated downmodulation of CXCR1 and CXCR2 cell surface expression or receptor signaling. Thus, these findings may provide further insight into the mechanisms of leukocyte regulation during immunologic and inflammatory responses.


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