scholarly journals Nuclear Factor (NF)-κB–regulated X-chromosome–linked iap Gene Expression Protects Endothelial Cells from Tumor Necrosis Factor α–induced Apoptosis

1998 ◽  
Vol 188 (1) ◽  
pp. 211-216 ◽  
Author(s):  
Christian Stehlik ◽  
Rainer de Martin ◽  
Ichiro Kumabashiri ◽  
Johannes A. Schmid ◽  
Bernd R. Binder ◽  
...  

By differential screening of tumor necrosis factor α (TNF-α) and lipopolysaccharide (LPS)- activated endothelial cells (ECs), we have identified a cDNA clone that turned out to be a member of the inhibitor of apoptosis (iap) gene family. iap genes function to protect cells from undergoing apoptotic death in response to a variety of stimuli. These iap genes, hiap1, hiap2, and xiap were found to be strongly upregulated upon treatment of ECs with the inflammatory cytokines TNF-α, interleukin 1β, and LPS, reagents that lead to activation of the nuclear transcription factor κB (NF-κB). Indeed, overexpression of IκBα, an inhibitor of NF-κB, suppresses the induced expression of iap genes and sensitizes ECs to TNF-α–induced apoptosis. Ectopic expression of one member of the human iap genes, human X-chromosome–linked iap (xiap), using recombinant adenovirus overrules the IκBα effect and protects ECs from TNF-α– induced apoptosis. We conclude that xiap represents one of the NF-κB–regulated genes that counteracts the apoptotic signals caused by TNF-α and thereby prevents ECs from undergoing apoptosis during inflammation.

Blood ◽  
2009 ◽  
Vol 113 (21) ◽  
pp. 5111-5120 ◽  
Author(s):  
Michael D. Milsom ◽  
Bernhard Schiedlmeier ◽  
Jeff Bailey ◽  
Mi-Ok Kim ◽  
Dandan Li ◽  
...  

AbstractEctopic delivery of HOXB4 elicits the expansion of engrafting hematopoietic stem cells (HSCs). We hypothesized that inhibition of tumor necrosis factor-α (TNF-α) signaling may be central to the self-renewal signature of HOXB4. Because HSCs derived from Fanconi anemia (FA) knockout mice are hypersensitive to TNF-α, we studied Fancc−/− HSCs to determine the physiologic effects of HOXB4 on TNF-α sensitivity and the relationship of these effects to the engraftment defect of FA HSCs. Overexpression of HOXB4 reversed the in vitro hypersensitivity to TNF-α of Fancc−/− HSCs and progenitors (P) and partially rescued the engraftment defect of these cells. Coexpression of HOXB4 and the correcting FA-C protein resulted in full correction compared with wild-type (WT) HSCs. Ectopic expression of HOXB4 resulted in a reduction in both apoptosis and reactive oxygen species in Fancc−/− but not WT HSC/P. HOXB4 overexpression was also associated with a significant reduction in surface expression of TNF-α receptors on Fancc−/− HSC/P. Finally, enhanced engraftment was seen even when HOXB4 was expressed in a time-limited fashion during in vivo reconstitution. Thus, the HOXB4 engraftment signature may be related to its effects on TNF-α signaling, and this pathway may be a molecular target for timed pharmacologic manipulation of HSC during reconstitution.


1999 ◽  
Vol 276 (3) ◽  
pp. F390-F397 ◽  
Author(s):  
Yan-Lin Guo ◽  
Baobin Kang ◽  
Li-Jun Yang ◽  
John R. Williamson

It has been proposed that ceramide acts as a cellular messenger to mediate tumor necrosis factor-α (TNF-α)-induced apoptosis. Based on this hypothesis, it was postulated that resistance of some cells to TNF-α cytotoxicity was due to an insufficient production of ceramide on stimulation by TNF-α. The present study was initiated to investigate whether this was the case in mesangial cells, which normally are insensitive to TNF-α-induced apoptosis. Our results indicate that although C2ceramide was toxic to mesangial cells, the cell death it induced differed both morphologically and biochemically from that induced by TNF-α in the presence of cycloheximide (CHX). The most apparent effect of C2ceramide was to cause cells to swell, followed by disruption of the cell membrane. It is evident that C2ceramide caused cell death by necrosis, whereas TNF-α in the presence of CHX killed the cells by apoptosis. C2ceramide did not mimic the effects of TNF-α on the activation of c-Jun NH2-terminal protein kinase and nuclear factor-κB transcription factor. Although mitogen-activated protein kinase [extracellular signal-related kinase (ERK)] was activated by both C2ceramide and TNF-α, such activation appeared to be mediated by different mechanisms as judged from the kinetics of ERK activation. Furthermore, the cleavage of cytosolic phospholipase A2during cell death induced by C2ceramide and by TNF-α in the presence of CHX showed distinctive patterns. The present study provides evidence that apoptosis and necrosis use distinctive signaling machinery to cause cell death.


2008 ◽  
Vol 367 (2) ◽  
pp. 474-480 ◽  
Author(s):  
Hideki Ohtsubo ◽  
Toshihiro Ichiki ◽  
Ikuyo Imayama ◽  
Hiroki Ono ◽  
Kae Fukuyama ◽  
...  

2010 ◽  
Vol 58 (14) ◽  
pp. 8430-8436 ◽  
Author(s):  
Domenico Trombetta ◽  
Francesco Cimino ◽  
Mariateresa Cristani ◽  
Giuseppina Mandalari ◽  
Antonella Saija ◽  
...  

2001 ◽  
Vol 276 (50) ◽  
pp. 47202-47211 ◽  
Author(s):  
Adeeb M. Al-Zoubi ◽  
Elena V. Efimova ◽  
Shashi Kaithamana ◽  
Osvaldo Martinez ◽  
Mohammed El-Azami El-Idrissi ◽  
...  

We identified a novel cDNA (IG20) that is homologous to cDNAs encoding a proteindifferentiallyexpressed innormal andneoplastic cells (DENN-SV) and human MADD (MAPK-activatingdeathdomain-containing protein). Furthermore, we show that the above variants most likely result from alternative splicing of a single gene. Functional analyses of these variants in permanently transfected HeLa cells revealed that IG20 and DENN-SV render them more susceptible or resistant to tumor necrosis factor α (TNF-α)-induced apoptosis, respectively. All variants tested could interact with TNF receptor 1 and activate ERK and nuclear factor κB. However, relative to control cells, only cells expressing IG20 showed enhanced TNF-α-induced activation of caspase-8 and -3, whereas cells expressing DENN-SV showed either reduced or no caspase activation. Transfection of these cells with a cDNA encoding CrmA maximally inhibited apoptosis in HeLa-IG20 cells. Our results show that IG20 can promote TNF-α-induced apoptosis and activation of caspase-8 and -3 and suggest that it may play a novel role in the regulation of the pleiotropic effects of TNF-α through alternative splicing.


Blood ◽  
1998 ◽  
Vol 92 (2) ◽  
pp. 558-566 ◽  
Author(s):  
Ramesh Sakiri ◽  
Belakere Ramegowda ◽  
Vernon L. Tesh

Shiga toxins (Stxs) produced by Shigella dysenteriae 1 andEscherichia coli have been implicated in the pathogenesis of bloody diarrhea, acute renal failure, and neurologic abnormalities. The pathologic hallmark of Stx-mediated tissue damage is the development of vascular lesions in which endothelial cells are swollen and detached from underlying basement membranes. However, in vitro studies using human vascular endothelial cells demonstrated minimal Stx-induced cytopathic effects, unless the target cells were also incubated with the proinflammatory cytokines tumor necrosis factor-α (TNF-α) or interleukin-1β (IL-1β). These cytokines have been shown to upregulate the expression of the Stx-binding membrane glycolipid globotriaosylceramide (Gb3). We show here that purified Stx1 induces TNF secretion by a human monocytic cell line, THP-1, in a dose- and time-dependent manner. Treatment of cells with both lipopolysaccharides (LPS) and Stx1 results in augmented TNF production. Treatment with the nontoxic Gb3-binding subunit of Stx1 or with an anti-Gb3 monoclonal antibody did not trigger TNF production. Northern blot analyses show that Stx1 causes increased TNF-α production through transcriptional activation. Increased levels of TNF-α mRNA are preceded by the nuclear translocation of the transcriptional activators NF-κB and AP-1 and the loss of cytoplasmic IκB-α. These data are the first to show that, in addition to direct cytotoxicity, Stxs possess cellular signaling capabilities sufficient to induce the synthesis of cytokines that may be necessary for target cell sensitization and the development of vascular lesions.


Blood ◽  
1998 ◽  
Vol 92 (2) ◽  
pp. 558-566 ◽  
Author(s):  
Ramesh Sakiri ◽  
Belakere Ramegowda ◽  
Vernon L. Tesh

Abstract Shiga toxins (Stxs) produced by Shigella dysenteriae 1 andEscherichia coli have been implicated in the pathogenesis of bloody diarrhea, acute renal failure, and neurologic abnormalities. The pathologic hallmark of Stx-mediated tissue damage is the development of vascular lesions in which endothelial cells are swollen and detached from underlying basement membranes. However, in vitro studies using human vascular endothelial cells demonstrated minimal Stx-induced cytopathic effects, unless the target cells were also incubated with the proinflammatory cytokines tumor necrosis factor-α (TNF-α) or interleukin-1β (IL-1β). These cytokines have been shown to upregulate the expression of the Stx-binding membrane glycolipid globotriaosylceramide (Gb3). We show here that purified Stx1 induces TNF secretion by a human monocytic cell line, THP-1, in a dose- and time-dependent manner. Treatment of cells with both lipopolysaccharides (LPS) and Stx1 results in augmented TNF production. Treatment with the nontoxic Gb3-binding subunit of Stx1 or with an anti-Gb3 monoclonal antibody did not trigger TNF production. Northern blot analyses show that Stx1 causes increased TNF-α production through transcriptional activation. Increased levels of TNF-α mRNA are preceded by the nuclear translocation of the transcriptional activators NF-κB and AP-1 and the loss of cytoplasmic IκB-α. These data are the first to show that, in addition to direct cytotoxicity, Stxs possess cellular signaling capabilities sufficient to induce the synthesis of cytokines that may be necessary for target cell sensitization and the development of vascular lesions.


2010 ◽  
Vol 31 (2) ◽  
pp. 640-647 ◽  
Author(s):  
Lei Wang ◽  
Michael Chopp ◽  
Hua Teng ◽  
Marianne Bolz ◽  
Moniche Ãlvarez Francisco ◽  
...  

Erythropoietin (EPO) enhances angiogenesis in the ischemic brain. Stroke induces secretion of tumor necrosis factor α (TNF-α). We investigated the effect of TNF-α on EPO-induced in vitro angiogenesis in cerebral endothelial cells. Using a capillary-like tubular formation assay, we found that transient incubation of primary rat cerebral microvascular endothelial cells (RECs) with TNF-α substantially upregulated EPO receptor (EPOR) expression and addition of EPO into TNF-α-treated RECs significantly augmented the capillary-like tube formation. Blockage of TNF receptor 1 (TNFR1) suppressed TNF-α-upregulated EPOR expression and abolished EPO-induced tube formation. Attenuation of endogenous EPOR with small interfering RNA (siRNA) also inhibited EPO-enhanced tube formation. Treatment of RECs with EPO activated nuclear factor-kappa B (NF-κB) and Akt. Incubation of the TNF-α-treated endothelial cells with EPO activated vascular endothelial growth factor (VEGF), VEGF receptor 2 (VEGFR2), angiopoietin 1 (Ang1), and Tie2. Blockage of VEGFR2 and Tie2 resulted in reduction of EPO-augmented tube formation. These data indicate that interaction of TNF-α with TNFR1 sensitizes cerebral endothelial cells for EPO-induced angiogenesis by upregulation of EPOR, which amplifies the effect of EPO on activation of the VEGF/VEGFR2 and Ang1/Tie2 pathways. Our results provide the evidence for crosslink between TNF and EPOR to coordinate the onset of angiogenesis in cerebral endothelial cells.


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