scholarly journals Tumour necrosis factor α decreases glucose-6-phosphatase gene expression by activation of nuclear factor κB

2004 ◽  
Vol 382 (2) ◽  
pp. 471-479 ◽  
Author(s):  
Rolf GREMPLER ◽  
Anne KIENITZ ◽  
Torsten WERNER ◽  
Marion MEYER ◽  
Andreas BARTHEL ◽  
...  
Keyword(s):  
Gene Expression ◽  
Protein Kinase ◽  
Tumour Necrosis Factor ◽  
Binding Sites ◽  
Tumour Necrosis ◽  
Promoter Activity ◽  
Nuclear Factor Κb ◽  
Mrna Levels ◽  
Nuclear Factor ◽  
Necrosis Factor

The key insulin-regulated gluconeogenic enzyme G6Pase (glucose-6-phosphatase) has an important function in the control of hepatic glucose production. Here we examined the inhibition of G6Pase gene transcription by TNF (tumour necrosis factor) in H4IIE hepatoma cells. TNF decreased dexamethasone/dibtuyryl cAMP-induced G6Pase mRNA levels. TNFα, but not insulin, led to rapid activation of NFκB (nuclear factor κB). The adenoviral overexpression of a dominant negative mutant of IκBα (inhibitor of NFκB α) prevented the suppression of G6Pase expression by TNFα, but did not affect that by insulin. The regulation of G6Pase by TNF was not mediated by activation of the phosphoinositide 3-kinase/protein kinase B pathway, extracellular-signal-regulated protein kinase or p38 mitogen-activated protein kinase. Reporter gene assays demonstrated a concentration-dependent down-regulation of G6Pase promoter activity by the transient overexpression of NFκB. Although two binding sites for NFκB were identified within the G6Pase promoter, neither of these sites, nor the insulin response unit or binding sites for Sp proteins, was necessary for the regulation of G6Pase promoter activity by TNFα. In conclusion, the data indicate that the activation of NFκB is sufficient to suppress G6Pase gene expression, and is required for the regulation by TNFα, but not by insulin. We propose that NFκB does not act by binding directly to the G6Pase promoter.

scholarly journals Hypoxia-inducible factor induction by tumour necrosis factor in normoxic cells requires receptor-interacting protein-dependent nuclear factor kappaB activation

2003 ◽  
Vol 370 (3) ◽  
pp. 1011-1017 ◽  
Author(s):  
YunJin JUNG ◽  
Jennifer S. ISAACS ◽  
Sunmin LEE ◽  
Jane TREPEL ◽  
Zheng-gang LIU ◽  
...  
Keyword(s):  
Tumour Necrosis Factor ◽  
Tumour Necrosis ◽  
Hypoxia Inducible Factor ◽  
Nuclear Factor Κb ◽  
Protein Stabilization ◽  
Mrna Levels ◽  
Nuclear Factor ◽  
Interacting Protein ◽  
Tnf Α ◽  
Necrosis Factor

Tumour necrosis factor α (TNF-α) binds to its receptor (TNFR1) and activates both death- and inflammation/survival-related signalling pathways. The inflammation and survival-related signalling cascade results in the activation of the transcription factor, nuclear factor κB (NF-κB) and requires recruitment of receptor-interacting protein (RIP) to TNFR1. The indispensable role of RIP in TNF-induced NF-κB activation has been demonstrated in RIP-/- mice and in cell lines derived from such mice. In the present study, we show that the TNF-α-induced accumulation of hypoxia-inducible factor 1α (HIF-1α) protein in normoxic cells is RIP-dependent. Exposing fibroblasts derived from RIP-/- mice to either cobalt or PMA resulted in an equivalent HIF-1α induction to that seen in RIP+/+ fibroblasts. In contrast, RIP-/- cells were unable to induce HIF-1α in response to TNF-α. Further, transient transfection of NIH 3T3 cells with an NF-κB super-repressor plasmid (an inhibitor of NF-κB activation) also prevented HIF-1α induction by TNF-α. Surprisingly, although HIF-1α mRNA levels remained unchanged after induction by TNF, induction of HIF-1α protein by the cytokine was completely blocked by pretreatment with the transcription inhibitors actinomycin D and 5,6-dichlorobenzimidazole riboside. Finally, TNF failed to induce both HIF-1α, made resistant to von Hippel—Lindau (VHL), and wild-type HIF-1α transfected into VHL-/- cells. These results indicate that HIF-1α induction by TNF-α in normoxic cells is mediated by protein stabilization but is nonetheless uniquely dependent on NF-κB-driven transcription. Thus the results describe a novel mechanism of HIF-1α up-regulation and they identify HIF-1α as a unique component of the NF-κB-mediated inflammatory/survival response.

scholarly journals JFC1 is transcriptionally activated by nuclear factor-κB and up-regulated by tumour necrosis factor α in prostate carcinoma cells

2002 ◽  
Vol 367 (3) ◽  
pp. 791-799 ◽  
Author(s):  
Sergio D. CATZ ◽  
Bernard M. BABIOR ◽  
Jennifer L. JOHNSON
Keyword(s):  
Tumour Necrosis Factor ◽  
Cell Lines ◽  
Prostate Carcinoma ◽  
Tumour Necrosis ◽  
Nuclear Factor Κb ◽  
Luciferase Reporter ◽  
Nuclear Factor ◽  
Tumour Necrosis Factor Α ◽  
Factor Α ◽  
Necrosis Factor

The human promoter region of JFC1, a phosphatidylinositol 3,4,5-trisphosphate binding ATPase, was isolated by amplification of a 549bp region upstream of the jfc1 gene by the use of a double-PCR system. By primer extension analysis we mapped the transcription initiation site at nucleotide −321 relative to the translation start site. Putative regulatory elements were identified in the jfc1 TATA-less promoter, including three consensus sites for nuclear factor-κB (NF-κB). We analysed the three putative NF-κB binding sites by gel retardation and supershift assays. Each of the putative NF-κB sites interacted specifically with recombinant NF-κB p50, and the complexes co-migrated with those formed by the NF-κB consensus sequence and p50. An antibody to p50 generated a supershifted complex for these NF-κB sites. These sites formed specific complexes with nuclear proteins from tumour necrosis factor α (TNFα)-treated WEHI 231 cells, which were supershifted with antibodies against p50 and p65. The jfc1 promoter was transcriptionally active in various cell lines, as determined by luciferase reporter assays following transfection with a jfc1 promoter luciferase vector. Co-transfection with NF-κB expression vectors or stimulation with TNFα resulted in significant transactivation of the jfc1 promoter construct, although transactivation of a mutated jfc1 promoter was negligible. The expression of a dominant negative IκB (inhibitor κB) decreased basal jfc1 promoter activity. The cell lines PC-3, LNCaP and DU-145, but not Epstein—Barr virus-transformed lymphocytes, showed a dramatic increase in the expression of JFC1 after treatment with TNFα, suggesting that transcriptional activation of JFC1 by the TNFα/NF-κB pathway is significant in prostate carcinoma cell lines.

Pentoxifylline inhibits acute HIV-1 replication in human T cells by a mechanism not involving inhibition of tumour necrosis factor synthesis or nuclear factor-κB activation

AIDS ◽  
1996 ◽  
Vol 10 (5) ◽  
pp. 469-475 ◽  
Author(s):  
Joaquín Navarro ◽  
M Carmen Punzón ◽  
Angel Pizarro ◽  
Eduardo Fernández-Cruz ◽  
Manuel Fresno ◽  
...  
Keyword(s):  
T Cells ◽  
Tumour Necrosis Factor ◽  
Tumour Necrosis ◽  
Nuclear Factor Κb ◽  
Nuclear Factor ◽  
Human T Cells ◽  
Acute Hiv ◽  
Hiv 1 ◽  
Necrosis Factor

Role of tumour necrosis factor receptor-1 and nuclear factor-κB in production of TNF-α-induced pro-inflammatory microparticles in endothelial cells

2014 ◽  
Vol 112 (09) ◽  
pp. 580-588 ◽  
Author(s):  
Sung Kyul Lee ◽  
Seung-Hee Yang ◽  
Il Kwon ◽  
Ok-Hee Lee ◽  
Ji Hoe Heo
Keyword(s):  
Endothelial Cells ◽  
Tumour Necrosis Factor ◽  
Tumour Necrosis ◽  
Nuclear Factor Κb ◽  
Tumour Necrosis Factor Receptor ◽  
Dependent Manner ◽  
Nuclear Factor ◽  
Tnf Α ◽  
Necrosis Factor

SummaryTumour necrosis factor-α (TNF-α) is upregulated in many inflammatory diseases and is also a potent agent for microparticle (MP) generation. Here, we describe an essential role of TNF-α in the production of endothelial cell-derived microparticles (EMPs) in vivo and the function of TNF-α-induced EMPs in endothelial cells. We found that TNF-α rapidly increased blood levels of EMPs in mice. Treatment of human umbilical vein endothelial cells (HUVECs) with TNF-α also induced EMP formation in a time-dependent manner. Silencing of TNF receptor (TNFR)-1 or inhibition of the nuclear factor-κB (NF-κB) in HUVECs impaired the production of TNF-α-induced EMP. Incubation of HUVECs with PKH-67-stained EMPs showed that endothelial cells readily engulfed EMPs, and the engulfed TNF-α-induced EMPs promoted the expression of pro-apoptotic molecules and upregulated intercellular adhesion molecule-1 level on the cell surface, which led to monocyte adhesion. Collectively, our findings indicate that the generation of TNF-α-induced EMPs was mediated by TNFR1 or NF-κB and that EMPs can contribute to apoptosis and inflammation of endothelial cells.

Thyrotropin modifies activation of nuclear factor κB by tumour necrosis factor α in rat thyroid cell line

2001 ◽  
Vol 354 (3) ◽  
pp. 573-579 ◽  
Author(s):  
Toyone KIKUMORI ◽  
Fukushi KAMBE ◽  
Takashi NAGAYA ◽  
Hiroomi FUNAHASHI ◽  
Hisao SEO
Keyword(s):  
Tumour Necrosis Factor ◽  
Tumour Necrosis ◽  
Nuclear Factor Κb ◽  
Luciferase Reporter ◽  
Nuclear Factor ◽  
Tumour Necrosis Factor Α ◽  
Tnf Α ◽  
Rat Thyroid ◽  
Factor Α ◽  
Necrosis Factor

We have recently demonstrated that nuclear factor κB (NF-κB) mediates the tumour necrosis factor α (TNF-α)-dependent expression of the gene encoding interleukin 6 (IL-6) in rat thyroid FRTL-5 cells cultured in the presence of thyrotropin (TSH). In the present study we investigated how TSH is involved in the activation of NF-κB by TNF-α in the cells. Electrophoretic mobility-shift assay revealed that, in the absence of TSH, TNF-α activated a single protein–DNA complex containing the p50 subunit but not other NF-κB subunits such as p65. In contrast, two distinct protein–DNA complexes were activated in the presence of TSH: the faster-migrating complex contained only p50 subunit; the slower-migrating complex consisted of p65–p50heterodimer. This TSH effect was mimicked by forskolin and thyroid-stimulating antibodies obtained from patients with Graves's disease, suggesting that an increase in intracellular cAMP is responsible for the induction of different NF-κBs by TNF-α. A transient transfection study with a luciferase reporter gene driven by multimerized NF-κB sites demonstrated that TNF-α increased the luciferase activities only in the presence of TSH, and that this increase was inhibited by the co-transfection of mutant p65, which prevented the function of wild-type p65 in a dominant-negative manner. Accordingly, TNF-α activated the expression of the IL-6 gene in the presence of TSH but not in its absence. Although the expression of the p105 gene, another known target for NF-κB, was increased by TNF-α in the absence of TSH, the presence of TSH further increased the mRNA level. Taken together, these observations indicate that the presence of TSH is crucial for the NF-κB-mediated actions of TNF-α on thyroid follicular cells.

scholarly journals Tumour necrosis factor α induces co-ordinated activation of rat GSH synthetic enzymes via nuclear factor κB and activator protein-1

2005 ◽  
Vol 391 (2) ◽  
pp. 399-408 ◽  
Author(s):  
Heping Yang ◽  
Nathaniel Magilnick ◽  
Xiaopeng Ou ◽  
Shelly C. Lu
Keyword(s):  
Promoter Activity ◽  
Nuclear Factor Κb ◽  
Mrna Levels ◽  
Nuclear Factor ◽  
Activator Protein 1 ◽  
Tumour Necrosis Factor Α ◽  
Synthetic Enzymes ◽  
H4iie Cells ◽  
Factor Α ◽  
Necrosis Factor

GSH synthesis occurs via two enzymatic steps catalysed by GCL [glutamate–cysteine ligase, made up of GCLC (GCL catalytic subunit), and GCLM (GCL modifier subunit)] and GSS (GSH synthetase). Co-ordinated up-regulation of GCL and GSS further enhances GSH synthetic capacity. The present study examined whether TNFα (tumour necrosis factor α) influences the expression of rat GSH synthetic enzymes. To facilitate transcriptional studies of the rat GCLM, we cloned its 1.8 kb 5′-flanking region. TNFα induces the expression and recombinant promoter activities of GCLC, GCLM and GSS in H4IIE cells. TNFα induces NF-κB (nuclear factor κB) and AP-1 (activator protein 1) nuclear-binding activities. Blocking AP-1 with dominant negative c-Jun or NF-κB with IκBSR (IκB super-repressor, where IκB stands for inhibitory κB) lowered basal expression and inhibited the TNFα-mediated increase in mRNA levels of all three genes. While all three genes have multiple AP-1-binding sites, only GCLC has a NF-κB-binding site. Overexpression with p50 or p65 increased c-Jun mRNA levels, c-Jun-dependent promoter activity and the promoter activity of GCLM and GSS. Blocking NF-κB also lowered basal c-Jun expression and blunted the TNFα-mediated increase in c-Jun mRNA levels. TNFα treatment resulted in increased c-Jun and Nrf2 (nuclear factor erythroid 2-related factor 2) nuclear binding to the antioxidant response element of the rat GCLM and if this was prevented, TNFα no longer induced the GCLM promoter activity. In conclusion, both c-Jun and NF-κB are required for basal and TNFα-mediated induction of GSH synthetic enzymes in H4IIE cells. While NF-κB may exert a direct effect on the GCLC promoter, it induces the GCLM and GSS promoters indirectly via c-Jun.

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