scholarly journals Activation of Nuclear Factor κb and bcl-x Survival Gene Expression by Nerve Growth Factor Requires Tyrosine Phosphorylation of IκBα

2001 ◽  
Vol 152 (4) ◽  
pp. 753-764 ◽  
Author(s):  
Nguyen Truc Bui ◽  
Antonia Livolsi ◽  
Jean-Francois Peyron ◽  
Jochen H.M. Prehn
Keyword(s):  
Gene Expression ◽  
Tyrosine Phosphorylation ◽  
Fluorescent Protein ◽  
Nuclear Translocation ◽  
Nuclear Factor Κb ◽  
Dominant Negative ◽  
Dominant Negative Mutant ◽  
Nuclear Factor ◽  
Human Neuroblastoma ◽  
Tnf Α

NGF has been shown to support neuron survival by activating the transcription factor nuclear factor-κB (NFκB). We investigated the effect of NGF on the expression of Bcl-xL, an anti–apoptotic Bcl-2 family protein. Treatment of rat pheochromocytoma PC12 cells, human neuroblastoma SH-SY5Y cells, or primary rat hippocampal neurons with NGF (0.1–10 ng/ml) increased the expression of bcl-xL mRNA and protein. Reporter gene analysis revealed a significant increase in NFκB activity after treatment with NGF that was associated with increased nuclear translocation of the active NFκB p65 subunit. NGF-induced NFκB activity and Bcl-xL expression were inhibited in cells overexpressing the NFκB inhibitor, IκBα. Unlike tumor necrosis factor-α (TNF-α), however, NGF-induced NFκB activation occurred without significant degradation of IκBs determined by Western blot analysis and time-lapse imaging of neurons expressing green fluorescent protein–tagged IκBα. Moreover, in contrast to TNF-α, NGF failed to phosphorylate IκBα at serine residue 32, but instead caused significant tyrosine phosphorylation. Overexpression of a Y42F mutant of IκBα potently suppressed NFG-, but not TNF-α–induced NFκB activation. Conversely, overexpression of a dominant negative mutant of TNF receptor-associated factor-6 blocked TNF-α–, but not NGF-induced NFκB activation. We conclude that NGF and TNF-α induce different signaling pathways in neurons to activate NFκB and bcl-x gene expression.

Brief hypoxic stress suppresses postbacteremic NF-κB activation and TNF-α bioactivity in perfused liver

2000 ◽  
Vol 279 (1) ◽  
pp. R99-R108 ◽  
Author(s):  
Laura L. Loftis ◽  
Cheryl A. Johanns ◽  
Andrew J. Lechner ◽  
George M. Matuschak
Keyword(s):  
Gene Expression ◽  
Nuclear Translocation ◽  
Nuclear Factor Κb ◽  
Mobility Shift ◽  
Gram Negative ◽  
Nuclear Extracts ◽  
Tnf Α ◽  
Cellular Hypoxia ◽  
Electrophoretic Mobility Shift Assays ◽  
Rat Livers

Reductions in hepatic O2 delivery are common early after gram-negative bacteremic sepsis owing to cardiopulmonary dysfunction and derangements in sinusoidal perfusion. Although gram-negative endotoxin and cellular hypoxia independently enhance activation of nuclear factor-κB (NF-κB) via generation of reactive O2 species (ROS), the combination of these stimuli downregulates hepatic TNF-α gene expression. Here we tested the hypothesis that hypoxic suppression of postbacteremic TNF-α gene expression is transcriptionally mediated by reduced activation of NF-κB. Buffer-perfused rat livers ( n = 52) were studied over 180 min after intraportal infection at t = 0 with 109 live Escherichia coli (EC), serotype O55:B5, or 0.9% NaCl controls under normoxic conditions, compared with 0.5 h of constant-flow hypoxia (Po 2 ∼41 ± 7 Torr) beginning at t = 30 min, followed by 120 min of reoxygenation. In parallel studies, tissue was obtained at peak hypoxia ( t = 60 min). To determine the role of xanthine oxidase (XO)-induced ROS in modulating NF-κB activity after hypoxia/reoxygenation (H/R), livers were pretreated with the XO inhibitor allopurinol, with results confirmed in organs of tungstate-fed animals. Electrophoretic mobility shift assays were performed on nuclear extracts of whole liver lysates using32P-labeled oligonucleotides specific for NF-κB. Compared with normoxic EC controls, hypoxia reduced postbacteremic NF-κB nuclear translocation and TNF-α bioactivity, independent of reoxygenation, tissue levels of reduced glutathione, or posthypoxic O2 consumption. XO inhibition reversed the hypoxic suppression of NF-κB nuclear translocation and ameliorated decreases in cell-associated TNF-α. Thus decreases in hepatic O2delivery reduce postbacteremic nuclear translocation of NF-κB and hepatic TNF-α biosynthesis by signaling mechanisms involving low-level generation of XO-mediated ROS.

Nuclear Factor-κB–Dependent Induction of Interleukin-8 Gene Expression by Tumor Necrosis Factor : Evidence for an Antioxidant Sensitive Activating Pathway Distinct From Nuclear Translocation

Blood ◽  
1999 ◽  
Vol 94 (6) ◽  
pp. 1878-1889 ◽  
Author(s):  
Spiros Vlahopoulos ◽  
Istvan Boldogh ◽  
Antonella Casola ◽  
Allan R. Brasier
Keyword(s):  
Gene Expression ◽  
Tumor Necrosis Factor ◽  
Transcriptional Activation ◽  
Tumor Necrosis ◽  
Nuclear Translocation ◽  
Gene Transfection ◽  
Nuclear Factor Κb ◽  
Interleukin 8 ◽  
Nuclear Factor ◽  
Necrosis Factor

Tumor necrosis factor  (TNF) is a pluripotent activator of inflammation by inducing a proinflammatory cytokine cascade. This phenomenon is mediated, in part, through inducible expression of the CXC chemokine, interleukin-8 (IL-8). In this study, we investigate the role of TNF-inducible reactive oxygen species (ROS) in IL-8 expression by “monocyte-like” U937 histiocytic lymphoma cells. TNF is a rapid activator of IL-8 gene expression by U937, producing a 50-fold induction of mRNA within 1 hour of treatment. In gene transfection assays, the effect of TNF requires the presence of an inducible nuclear factor-κB (NF-κB) (Rel A) binding site in the IL-8 promoter. TNF treatment induces a rapid translocation of the 65 kD transcriptional activator NF-κB subunit, Rel A, whose binding in the nucleus occurs before changes in intracellular ROS. Pretreatment (or up to 15 minutes posttreatment) relative to TNF with the antioxidant dimethyl sulfoxide (DMSO) (2% [vol/vol]) blocks 80% of NF-κB–dependent transcription. Surprisingly, however, DMSO has no effect on inducible Rel A binding. Similar selective effects on NF-κB transcription are seen with the unrelated antioxidants, N-acetylcysteine (NAC) and vitamin C. These data indicate that TNF induces a delayed ROS-dependent signalling pathway that is required for NF-κB transcriptional activation and is separable from that required for its nuclear translocation. Further definition of this pathway will yield new insights into inflammation initiated by TNF signalling.

scholarly journals Zyxin regulates migration of renal epithelial cells through activation of hepatocyte nuclear factor-1β

2013 ◽  
Vol 305 (1) ◽  
pp. F100-F110 ◽  
Author(s):  
Yun-Hee Choi ◽  
Brian T. McNally ◽  
Peter Igarashi
Keyword(s):  
Transcription Factor ◽  
Epithelial Cells ◽  
Nuclear Translocation ◽  
Dominant Negative ◽  
Dominant Negative Mutant ◽  
Epithelial Tissue ◽  
Nuclear Factor ◽  
Hepatocyte Nuclear Factor ◽  
Lim Domain ◽  
Renal Epithelial Cells

Hepatocyte nuclear factor-1β (HNF-1β) is an epithelial tissue-specific transcription factor that regulates gene expression in the kidney, liver, pancreas, intestine, and other organs. Mutations of HNF-1β in humans produce renal cysts and congenital kidney anomalies. Here, we identify the LIM-domain protein zyxin as a novel binding partner of HNF-1β in renal epithelial cells. Zyxin shuttles to the nucleus where it colocalizes with HNF-1β. Immunoprecipitation of zyxin in leptomycin B-treated cells results in coprecipitation of HNF-1β. The protein interaction requires the second LIM domain of zyxin and two distinct domains of HNF-1β. Overexpression of zyxin stimulates the transcriptional activity of HNF-1β, whereas small interfering RNA silencing of zyxin inhibits HNF-1β-dependent transcription. Epidermal growth factor (EGF) induces translocation of zyxin into the nucleus and stimulates HNF-1β-dependent promoter activity. The EGF-mediated nuclear translocation of zyxin requires activation of Akt. Expression of dominant-negative mutant HNF-1β, knockdown of zyxin, or inhibition of Akt inhibits EGF-stimulated cell migration. These findings reveal a novel pathway by which extracellular signals are transmitted to the nucleus to regulate the activity of a transcription factor that is essential for renal epithelial differentiation.

scholarly journals Signalling cross-talk between hepatocyte nuclear factor 4α and growth-hormone-activated STAT5b

2006 ◽  
Vol 397 (1) ◽  
pp. 159-168 ◽  
Author(s):  
Soo-Hee Park ◽  
Christopher A. Wiwi ◽  
David J. Waxman
Keyword(s):  
Growth Hormone ◽  
Tyrosine Phosphorylation ◽  
Cross Talk ◽  
Transcriptional Activity ◽  
Nuclear Translocation ◽  
Dominant Negative ◽  
Janus Kinase ◽  
Nuclear Factor ◽  
Hepatocyte Nuclear Factor ◽  
Hepatocyte Nuclear Factor 4Α

In the present study, we have characterized signalling cross-talk between STAT5b (signal transducer and activator of transcription 5b) and HNF4α (hepatocyte nuclear factor 4α), two major regulators of sex-dependent gene expression in the liver. In a HepG2 liver cell model, HNF4α strongly inhibited β-casein and ntcp (Na+/taurocholate cotransporting polypeptide) promoter activity stimulated by GH (growth hormone)-activated STAT5b, but had no effect on interferon-γ-stimulated STAT1 transcriptional activity. By contrast, STAT5b synergistically enhanced the transcriptional activity of HNF4α towards the ApoCIII (apolipoprotein CIII) promoter. The inhibitory effect of HNF4α on STAT5b transcription was associated with the inhibition of GH-stimulated STAT5b tyrosine phosphorylation and nuclear translocation. The short-chain fatty acid, butyrate, reversed STAT5b transcriptional inhibition by HNF4α, but did not reverse the inhibition of STAT5b tyrosine phosphorylation. HNF4α inhibition of STAT5b tyrosine phosphorylation was not reversed by pervanadate or by dominant-negative phosphotyrosine phosphatase 1B, suggesting that it does not result from an increase in STAT5b dephosphorylation. Rather, HNF4α blocked GH-stimulated tyrosine phosphorylation of JAK2 (Janus kinase 2), a STAT5b tyrosine kinase. Thus STAT5b and HNF4α exhibit bi-directional cross-talk that may augment HNF4α-dependent gene transcription while inhibiting STAT5b transcriptional activity via the inhibitory effects of HNF4α on JAK2 phosphorylation, which leads to inhibition of STAT5b signalling initiated by the GH receptor at the cell surface.

Biologic sequelae of nuclear factor–κB blockade in multiple myeloma: therapeutic applications

Blood ◽  
2002 ◽  
Vol 99 (11) ◽  
pp. 4079-4086 ◽  
Author(s):  
Nicholas Mitsiades ◽  
Constantine S. Mitsiades ◽  
Vassiliki Poulaki ◽  
Dharminder Chauhan ◽  
Paul G. Richardson ◽  
...  
Keyword(s):  
Caspase 3 ◽  
Nuclear Translocation ◽  
Nuclear Factor Κb ◽  
Inhibitor Of Apoptosis ◽  
Caspase 8 ◽  
Nuclear Factor ◽  
Inhibitor Of Apoptosis Protein ◽  
Tnf Α ◽  
Apoptosis Protein ◽  
Induced Apoptosis

The transcription factor nuclear factor–κB (NF-κB) confers significant survival potential in a variety of tumors. Several established or novel anti–multiple myeloma (anti-MM) agents, such as dexamethasone, thalidomide, and proteasome inhibitors (PS-341), inhibit NF-κB activity as part of their diverse actions. However, studies to date have not delineated the effects of specific inhibition of NF-κB activity in MM. We therefore investigated the effect of SN50, a cell-permeable specific inhibitor of NF-κB nuclear translocation and activity, on MM cells. SN50 induced apoptosis in MM cell lines and patient cells; down-regulated expression of Bcl-2, A1, X-chromosome–linked inhibitor-of-apoptosis protein (XIAP), cellular inhibitor-of-apoptosis protein 1 (cIAP-1), cIAP-2, and survivin; up-regulated Bax; increased mitochondrial cytochromec release into the cytoplasm; and activated caspase-9 and caspase-3, but not caspase-8. We have previously demonstrated that tumor necrosis factor–α (TNF-α) is present locally in the bone marrow microenvironment and induces NF-κB–dependent up-regulation of adhesion molecules on both MM cells and bone marrow stromal cells, with resultant increased adhesion. In this study, TNF-α alone induced NF-κB nuclear translocation, cIAP-1 and cIAP-2 up-regulation, and MM cell proliferation; in contrast, SN50 pretreatment sensitized MM cells to TNF-α–induced apoptosis and cleavage of caspase-8 and caspase-3, similar to our previous finding of SN50-induced sensitization to apoptosis induced by the TNF-α family member TNF-related apoptosis-inducing ligand (TRAIL)/Apo2L. Moreover, SN50 inhibited TNF-α–induced expression of another NF-κB target gene, intercellular adhesion molecule–1. Although the p38 inhibitor PD169316 did not directly kill MM cells, it potentiated the apoptotic effect of SN50, suggesting an interaction between the p38 and NF-κB pathways. Our results therefore demonstrate that NF-κB activity in MM cells promotes tumor-cell survival and protects against apoptotic stimuli. These studies provide the framework for targeting NF-κB activity in novel biologically based therapies for MM.

scholarly journals Lutonarin from Barley Seedlings Inhibits the Lipopolysacchride-Stimulated Inflammatory Response of RAW 264.7 Macrophages by Suppressing Nuclear Factor-κB Signaling

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1571
Author(s):  
Ji Yeong Yang ◽  
So-Yeun Woo ◽  
Mi Ja Lee ◽  
Hyun Young Kim ◽  
Jin Hwan Lee ◽  
...  
Keyword(s):  
Nuclear Translocation ◽  
Nuclear Factor Κb ◽  
Ultra Performance Liquid Chromatography ◽  
Raw 264.7 ◽  
Nuclear Factor ◽  
Raw 264.7 Macrophages ◽  
Tnf Α ◽  
Anti Inflammatory ◽  
Oxide Synthase ◽  
Necrosis Factor

Extracts from barley seedlings (BS) have known antioxidant and anti-inflammatory activities. The flavonoid lutonarin (LN) is a component of BS extract and has several known bioactivities. Here, we evaluated LN anti-inflammatory efficacy against lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. Lutonarin was isolated from BS by methanol extraction and characterized by ultra-performance liquid chromatography and quadrupole time-of-flight tandem mass spectrometry (UPLC-Q-TOF-MS/MS). Lutonarin did not reduce the viability or enhance the apoptosis rate of RAW 264.7 macrophages at concentrations up to 150 µM. Concentrations within 20–60 µM dose-dependently suppressed the LPS-induced expression, phosphorylation, and nuclear translocation of the inflammatory transcription factor nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB). Furthermore, LN suppressed the LPS-induced upregulation of proinflammatory cytokines interleukin (IL)-6 and tumor necrosis factor (TNF)-α and of the inflammatory enzyme cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS). Lutonarin may be a safe and effective therapeutic agent for alleviation of pathological inflammation.

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