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.

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.

Activated Protein C Inhibits Lipopolysaccharide-Induced Tumor Necrosis Factor-α Production by Inhibiting Activation of both Nuclear Factor-κB and Activator Protein-1 in Human Monocytes

2002 ◽  
Vol 88 (08) ◽  
pp. 267-273 ◽  
Author(s):  
Mehtap Yuksel ◽  
Mitsuhiro Uchiba ◽  
Seikoh Horiuchi ◽  
Hiroaki Okabe ◽  
Kenji Okajima
Keyword(s):  
Protein C ◽  
Tumor Necrosis ◽  
Activated Protein C ◽  
Nuclear Factor Κb ◽  
Nuclear Factor ◽  
Activator Protein 1 ◽  
Tnf Α ◽  
Target Sites ◽  
Factor Α ◽  
Necrosis Factor

SummaryActivated protein C (APC), an important natural anticoagulant, inhibits tumor necrosis factor-α (TNF-α) production and attenuates various deleterious events induced by lipopolysaccharide (LPS), contributing thereby to a significant reduction of mortality in patients with severe sepsis. In this study, we investigated the mechanism(s) by which APC inhibits TNF-α production by LPS-stimulated human monocytes in vitro. Although APC inhibited LPS-induced TNF-α production in a concentration-dependent fashion, diisopropyl fluorophosphate-treated APC, an active-site-blocked APC, had no effect. APC inhibited both the binding of nuclear factor-κB (NF-κB) to target sites and the degradation of IκBα. APC also inhibited both the binding of activator protein-1 (AP-1) to target sites and the activation of mitogen-activated protein kinase pathways. These observations strongly suggest that APC inhibited LPS-induced TNF-α production by inhibiting the activation of both NF-κB and AP-1 and that the inhibitory activity of APC might depend on its serine protease activity. These results would at least partly explain the mechanism(s) by which APC reduces the tissue injury seen in animal models of sepsis and in patients with sepsis.

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