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Chaurasiya SK. Tuberculosis: Smart manipulation of a lethal host. Microbiol Immunol 2018; 62:361-379. [PMID: 29687912 DOI: 10.1111/1348-0421.12593] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 03/21/2018] [Accepted: 04/16/2018] [Indexed: 11/28/2022]
Abstract
Tuberculosis (TB) caused by Mycobacterium tuberculosis remains a global threat to human health. Development of drug resistance and co-infection with HIV has increased the morbidity and mortality caused by TB. Macrophages serve as primary defense against microbial infections, including TB. Upon recognition and uptake of mycobacteria, macrophages initiate a series of events designed to lead to generation of effective immune responses and clearance of infection. However, pathogenic mycobacteria utilize multiple mechanisms for manipulating macrophage responses to protect itself from being killed and to survive within these cells that are designed to kill them. The outcomes of mycobacterial infection are determined by several host- and pathogen-related factors. Significant advancements in understanding mycobacterial pathogenesis have been made in recent years. In this review, some of the important factors/mechanisms regulating mycobacterial survival inside macrophages are discussed.
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Affiliation(s)
- Shivendra K Chaurasiya
- Host-pathogen Interaction and Signal Transduction Laboratory, Department of Microbiology, School of Biological Sciences, Dr. Hari Singh Gour University, Sagar, MP-470003, India
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Ethyl Acetate Extract of Artemisia anomala S. Moore Displays Potent Anti-Inflammatory Effect. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2014; 2014:681352. [PMID: 24744815 PMCID: PMC3972921 DOI: 10.1155/2014/681352] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Accepted: 02/04/2014] [Indexed: 01/13/2023]
Abstract
Artemisia anomala S. Moore has been widely used in China to treat inflammatory diseases for hundreds of years. However, mechanisms associated with its anti-inflammatory effect are not clear. In this study, we prepared ethyl acetate, petroleum ether, n-BuOH, and aqueous extracts from ethanol extract of Artemisia anomala S. Moore. Comparing anti-inflammatory effects of these extracts, we found that ethyl acetate extract of this herb (EAFA) exhibited the strongest inhibitory effect on nitric oxide (NO) production in LPS/IFNγ-stimulated RAW264.7 cells. EAFA suppressed the production of NO in a time- and dose-dependent manner without eliciting cytotoxicity to RAW264.7 cells. To understand the molecular mechanism underlying EAFA's anti-inflammatory effect, we showed that EAFA increased total cellular anti-oxidant capacity while reducing the amount of inducible nitric oxide synthase (iNOS) in stimulated RAW264.7 cells. EAFA also suppressed the expression of IL-1β and IL-6, whereas it elevates the level of heme oxygenase-1. These EAFA-induced events were apparently associated with NF-κB and MAPK signaling pathways because the DNA binding activity of p50/p65 was impaired and the activities of both ERK and JNK were decreased in EFEA-treated cells comparing to untreated cells. Our findings suggest that EAFA exerts its anti-inflammatory effect by inhibiting the expression of iNOS.
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Nakajima S, Kitamura M. Bidirectional regulation of NF-κB by reactive oxygen species: a role of unfolded protein response. Free Radic Biol Med 2013; 65:162-174. [PMID: 23792277 DOI: 10.1016/j.freeradbiomed.2013.06.020] [Citation(s) in RCA: 225] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2013] [Revised: 06/06/2013] [Accepted: 06/07/2013] [Indexed: 12/15/2022]
Abstract
Nuclear factor-κB (NF-κB) is a transcription factor that plays a crucial role in coordinating innate and adaptive immunity, inflammation, and apoptotic cell death. NF-κB is activated by various inflammatory stimuli including peptide factors and infectious microbes. It is also known as a redox-sensitive transcription factor activated by reactive oxygen species (ROS). Over the past decades, various investigators focused on the role of ROS in the activation of NF-κB by cytokines and lipopolysaccharides. However, recent studies also suggested that ROS have the potential to repress NF-κB activity. Currently, it is not well addressed how ROS regulate activity of NF-κB in a bidirectional fashion. In this paper, we summarize evidence for positive and negative regulation of NF-κB by ROS, possible redox-sensitive targets for NF-κB signaling, and mechanisms underlying biphasic and bidirectional influences of ROS on NF-κB, especially focusing on a role of ROS-mediated induction of endoplasmic reticulum stress.
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Affiliation(s)
- Shotaro Nakajima
- Department of Molecular Signaling, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Shimokato 1110, Chuo, Yamanashi 409-3898, Japan
| | - Masanori Kitamura
- Department of Molecular Signaling, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Shimokato 1110, Chuo, Yamanashi 409-3898, Japan.
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Seto T, Yoshitake M, Ogasawara T, Ikari J, Sakamoto A, Hatano M, Hirata H, Fukuda T, Kuriyama T, Tatsumi K, Tokuhisa T, Arima M. Bcl6 in pulmonary epithelium coordinately controls the expression of the CC-type chemokine genes and attenuates allergic airway inflammation. Clin Exp Allergy 2011; 41:1568-78. [PMID: 21801248 DOI: 10.1111/j.1365-2222.2011.03836.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
BACKGROUND There is synteny in the CC-type chemokine gene clusters between humans (CCL2/MCP-1, CCL7MCP-3, CCL11/eotaxin, CCL8/MCP-2, CCL13/MCP-4, and CCL1/I-309) and mice (CCL2, CCL7, CCL11, CCL12/MCP-5, CCL8, and CCL1). OBJECTIVE As many putative Bcl6/STAT-binding sequences are observed in the clusters, we examined the roles of a transcriptional repressor Bcl6 and the regional histone modification in the expression of these chemokine genes in pulmonary epithelium. METHODS We generated transgenic (Tg) mice carrying the Bcl6 or the dominant-negative (DN)-Bcl6 gene under the control of the surfactant protein C (SPC) promoter that induces the exogenous gene expression in the distal lung epithelium. For in vitro studies, A549, alveolar type II-like epithelial cell line transfected with the SPC-DN-Bcl6 gene were stimulated with IL-4+TNF-α, and Bcl6 or STAT6 binding to and histone modification of the cluster in the transfectants were analysed by chromatin immunoprecipitation assays. Tg mice sensitized with ovalbumin (OVA) were challenged with OVA inhalation. The amounts of mRNAs in each sample were analysed by quantitative RT-PCR. RESULTS The amount of Bcl6 bound to the cluster decreased in A549 cells stimulated with IL-4 and TNF-α, whereas STAT6 binding increased in association with regional histone H3-K9/14 acetylation and H3-K4 methylation. The expression of all chemokine genes in the gene cluster was augmented in activated A549 cells transfected with the DN-Bcl6 gene. We also induced allergic airway inflammation in Tg mice. Expression of the chemokine genes and infiltrated cell numbers in the lungs of these Tg mice with allergic airway inflammation were inversely correlated with the amount of Bcl6 in the lungs. CONCLUSION AND CLINICAL RELEVANCE Expression of the pulmonary epithelium-derived CC-type chemokine genes in the cluster is orchestrated by the conserved machinery related to Bcl6. Thus, Bcl6 in pulmonary epithelium may be a critical regulator for pathogenesis of various pulmonary inflammatory diseases.
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Affiliation(s)
- T Seto
- Department of Developmental Genetics (H2), Graduate School of Medicine, Chiba University, Chiba, Japan
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Volanti C, Matroule JY, Piette J. Involvement of Oxidative Stress in NF-κB Activation in Endothelial Cells Treated by Photodynamic Therapy¶. Photochem Photobiol 2007. [DOI: 10.1562/0031-8655(2002)0750036ioosin2.0.co2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Bubici C, Papa S, Dean K, Franzoso G. Mutual cross-talk between reactive oxygen species and nuclear factor-kappa B: molecular basis and biological significance. Oncogene 2006; 25:6731-48. [PMID: 17072325 DOI: 10.1038/sj.onc.1209936] [Citation(s) in RCA: 317] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Reactive oxygen species (ROS) are emerging as key effectors in signal transduction. This role of ROS is especially evident in the pathways leading to programmed cell death (PCD) elicited in response to certain stress stimuli and cytokines. In these pathways, cytotoxic ROS signaling appears to be mediated in part by activation of the c-Jun-N-terminal kinase (JNK) mitogen-activated protein kinase (MAPK) cascade. Another pathway that is under ROS-mediated control in some systems is that leading to activation of transcription factor nuclear factor-kappa B (NF-kappaB), which is a central regulator of immunity, inflammation and cell survival. Remarkably, new evidence has unveiled the existence of a reciprocal, negative control that NF-kappaB exerts on ROS and JNK activities. This NF-kappaB-imposed restraint on ROS and JNK signaling is crucial for antagonism of PCD elicited by the proinflammatory cytokine tumor necrosis factor (TNF)alpha and likely other triggers. Effectors of this antagonistic cross-talk between NF-kappaB and ROS/JNK pathways have recently been identified. Because of the key roles that the prosurvival function of NF-kappaB plays in organismal physiology and disease, gaining a further mechanistic understanding of this cross-talk and NF-kappaB-dependent survival may be key to developing new therapies for the treatment of widespread human illnesses, such as cancer and chronic inflammatory conditions.
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Affiliation(s)
- C Bubici
- The Ben May Institute for Cancer Research, The University of Chicago, Chicago, IL 60637, USA
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Chang JW, Kim CS, Kim SB, Park SK, Park JS, Lee SK. Proinflammatory cytokine-induced NF-kappaB activation in human mesangial cells is mediated through intracellular calcium but not ROS: effects of silymarin. Nephron Clin Pract 2006; 103:e156-65. [PMID: 16636588 DOI: 10.1159/000092906] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2005] [Accepted: 01/13/2006] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND It is not fully understood whether intracellular calcium and/or reactive oxygen species (ROS) are involved in nuclear factor-kappaB (NF-kappaB) activation by proinflammatory cytokines. Silymarin exhibits anti-inflammatory and antioxidant effects but the effect of silymarin in human mesangial cells is largely unknown. METHOD NF-kappaB binding activity was measured by electrophoretic mobility shift assay. Intracellular calcium was monitored by confocal microscopy using Fluo-3 and intracellular ROS production was determined by flow cytometry. Monocyte chemoattractant protein-1 (MCP-1) expression was measured by Northern blot analysis and ELISA. RESULTS NF-kappaB was activated within 30 min by tumor necrosis factor-alpha (TNF-alpha) or interleukin-1beta (IL-1beta). Intracellular ROS was not produced until 30 min and also antioxidants such as N-acetylcysteine and tiron had no effect on the TNF-alpha- or IL-1beta-induced NF-kappaB activation. Intracellular calcium was increased by TNF-alpha and IL-1beta. Furthermore, a calcium chelator, BAPTA-AM, attenuated the NF-kappaB activation. Silymarin dose-dependently inhibited the TNF-alpha- or IL-1beta-induced NF-kappaB activation and MCP-1 expression. Silymarin also inhibited TNF-alpha-induced intracellular calcium. CONCLUSIONS Induction of NF-kappaB within 30 min by TNF-alpha- and IL-1beta was mediated through intracellular calcium but not ROS. Silymarin inhibited TNF-alpha-induced calcium-dependent NF-kappaB activation irrespective of its antioxidant effect.
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Affiliation(s)
- Jai Wong Chang
- Department of Internal Medicine, Urology and Asan Institute for Life Sciences, College of Medicine, University of Ulsan, Seoul, Korea
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Baouz S, Giron-Michel J, Azzarone B, Giuliani M, Cagnoni F, Olsson S, Testi R, Gabbiani G, Canonica GW. Lung myofibroblasts as targets of salmeterol and fluticasone propionate: inhibition of alpha-SMA and NF-kappaB. Int Immunol 2005; 17:1473-81. [PMID: 16210331 DOI: 10.1093/intimm/dxh325] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Lung myofibroblasts play a major role in the pathophysiology of asthma, contributing not only to tissue remodelling but also to airway inflammation. Nevertheless, only recently, attention has been focused on these cells as potential targets for anti-allergic drugs. Herein, we analysed the pharmacological response of lung myofibroblasts to beta2-agonists associated or not to inhaled corticosteroids, investigating their effects on (i) the constitutive and transforming growth factor-beta (TGF-beta)-induced expression of alpha-smooth muscle actin (alpha-SMA), the main functional marker of myofibroblastic differentiation and contractility; (ii) isometric contraction and (iii) tumour necrosis factor-alpha (TNF-alpha)-induced nuclear translocation of the pro-inflammatory transcription factor nuclear factor-kappaB (NF-kappaB). The beta2-agonist salmeterol (SMl) has on human lung myofibroblasts new direct anti-contractile/anti-inflammatory effects that are amplified by the combined use of low concentrations of the glucocorticoid fluticasone propionate (FP). First, SMl and/or FP (10(-12) M) inhibits the constitutive and TGF-beta-induced expression of alpha-SMA. Second, the two drugs block the TNF-alpha-induced nuclear translocation of the pro-inflammatory transcription factor NF-kappaB. Finally, SMl decreases TNF- alpha-induced production of the inflammatory cytokine IL-6. The complementary anti-inflammatory/ anti-contractile effects displayed by SMl and FP on lung myofibroblasts in vitro may be related to the improvement in lung function and symptom control obtained in vivo by the early use of low doses of glucocorticoids in combination with long-acting beta2-agonists.
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Affiliation(s)
- Soria Baouz
- Institut National de la Santé et de la Recherche Médicale 506, Villejuif, France
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Gubbay O, Guo W, Rae MT, Niven D, Langdon SP, Hillier SG. Inflammation-associated gene expression is altered between normal human ovarian surface epithelial cells and cell lines derived from ovarian adenocarcinomas. Br J Cancer 2005; 92:1927-33. [PMID: 15870720 PMCID: PMC2361768 DOI: 10.1038/sj.bjc.6602568] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Ovulation is believed to contribute to the development of ovarian cancers that derive from the ovarian surface epithelium (OSE). The process of ovulation is synonymous with inflammation and inflammatory cytokines such as interleukin-1α (IL-1α) have recently been shown to induce both inflammatory and anti-inflammatory responses in human OSE (HOSE) cells. In this study we directly compared levels of IL-1α-induced gene expression by analysing the levels of 11β-hydroxysteroid dehydrogenase (11βHSD) types 1 (11βHSD-1) and 2 (11βHSD-2), cyclooxygenase-2 (COX-2), IL-1 receptor (IL-1R) and glucocorticoid receptor α (GRα) mRNA between normal HOSE cells and cell lines derived from poorly differentiated (SKOV-3, BG-1, PEO-4) and well-differentiated (PEO-14) ovarian adenocarcinoma. In HOSE cell cultures, and to a lesser extent PEO-14 cells, the basal mRNA levels of COX-2 and 11βHSD-1 were relatively high and further shown to be induced in response to IL-1α (for HOSE cells; >20-fold, P<0.05 and PEO-14 cells; >3fold, P<0.05). However, whereas HOSE cells expressed a low level of 11βHSD-2 mRNA that was only mildly responsive to IL-1α (1.3-fold, P<0.001), all cell lines exhibited a higher basal level of 11βHSD-2 mRNA that was in some cases further stimulated in PEO-4 cells (five-fold; P<0.05) or suppressed in SKOV-3 cells (two-fold; P<0.01) in response to IL-1α. All cells tested expressed IL-1R and, with the exception of BG-1, GRα. These results indicate that cell lines derived from ovarian cancers have lost the ability to respond normally to inflammatory cytokines such as IL-1α. The finding that normal OSE cells, in contrast to cell lines derived from patients with ovarian adenocarcinoma, abundantly express 11βHSD-1 mRNA but are essentially devoid of 11βHSD-2 mRNA supports the concept that the pattern of 11βHSD isoform gene expression is a defining feature of neoplastic cellular transformation, which might have particular relevance to the ovary.
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Affiliation(s)
- O Gubbay
- Centre for Reproductive Biology, The Chancellor's Building, University of Edinburgh, 49 Little France Crescent, Old Dalkeith Road, Edinburgh EH16 4SB, UK.
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Abstract
Reactive oxygen species (ROS) initiate activation of the transcription factor NF-kappaB in a variety of cell systems. Perhaps the most potent biological source of ROS is the NADPH oxidase of phagocytic cells, a multi-component system that catalyzes the formation of superoxide anion. Although phagocytes use this oxidase to kill ingested microorganisms, the products also mediate a broad range of biological oxidation reactions and some evidence exists for activation of NF-kappaB through this mechanism. Moreover, the components of the phagocyte NADPH oxidase are present in certain non-phagocytic cells and recently discovered homologues of the catalytic component gp91(phox) are expressed in a number of tissues. We explored the hypothesis that the products of NADPH oxidases cause the activation of NF-kappaB. K562 human erythrokeukemia cells transfected with constructs for expression of gp91(phox), plus other essential NADPH oxidase components generated substantial amounts of superoxide when activated with phorbol ester, lesser amounts with arachidonic acid exposure, and none with TNFalpha. Gel shift assays demonstrated induction of NF-kappaB in K562 cells exposed to TNFalpha and specificity was shown by oligonucleotide competition. Supershift assays demonstrated the presence in nuclear complexes of the NF-kappaB components p65/RelA and p50. Nuclear complexes of identical electrophoretic mobility were induced in phorbol ester-stimulated K562 cells that expressed the complete NADPH oxidase system, but not in cells lacking one of the essential oxidase components. K562 cells were relatively resistant to NF-kappaB induction by exogenous peroxide, but certain other cell types (HEK293 and HeLaS3) demonstrated such induction upon exposure to reagent hydrogen peroxide or glucose oxidase plus glucose and this was blocked by catalase. Finally, we found a biphasic pattern of gp91(phox) expression in rat liver during aging. High levels observed in young animals decreased in middle age, but increased again in old age. Collectively, these studies demonstrate the potential for NADPH-dependent induction of NF-kappaB and raise the possibility of a role for this pathway in the biology of aging.
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Affiliation(s)
- Robert A Clark
- Department of Medicine, University of Texas Health Science Center and South Texas Veterans Health Care System, San Antonio, TX 78229-3900, USA.
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Haase MG, Klawitter A, Geyer P, Alheit H, Baumann M, Kriegel TM, Kasper M, Baretton GB. Sustained elevation of NF-kappaB DNA binding activity in radiation-induced lung damage in rats. Int J Radiat Biol 2004; 79:863-77. [PMID: 14698955 DOI: 10.1080/09553000310001632903] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
PURPOSE To characterize the cellular distribution and DNA binding activity of the nuclear factor kappaB (NF-KappaB) in a model of radiation-induced lung damage in the rat. MATERIAL AND METHODS The right lung of Fischer rats was irradiated with a single dose of 20 Gy. The cellular distributions of NF-KappaB proteins and mRNA were detected with immunohistochemistry and in-situ hybridization respectively. The DNA binding activity of NF-KappaB, nuclear and cytoplasmic levels of NF-KappaB proteins, and kinase activity towards IkappaBalpha (IKappaBAlpha) were determined using electrophoretic mobility shift assays (EMSA), Western blots and kinase assays, respectively. The mRNA level of interleukin 6 (IL-6) was determined using quantitative room temperature polymerase chain reaction. RESULTS There was a continuous elevation of NF-KappaB DNA binding activity in the rat lung after ionizing irradiation over 6 months. The irradiated lung tissue exhibited an increased kinase activity towards IKappaBAlpha and a selective loss of nuclear IKappaBAlpha. The NF-KappaB-DNA binding complex switched from p50-p65 heterodimers in normal lung tissue to p50 homodimers in irradiated lung tissue. The increased level of IL-6 mRNA suggests transcriptional activation of NF-KappaB-dependent genes in the irradiated rat lung. CONCLUSIONS The DNA binding activity of NF-KappaB is continuously activated after irradiation of the rat lung by loss of nuclear IKappaBAlpha. This might play a role in sustaining chronic inflammation and hyperproliferation of mesenchymal cells after irradiation.
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Affiliation(s)
- M G Haase
- Department of Pathology, Carl Gustav Caruis Medical Faculty, Dresden University of Technology, Germany.
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Bécuwe P, Bianchi A, Didelot C, Barberi-Heyob M, Dauça M. Arachidonic acid activates a functional AP-1 and an inactive NF-kappaB complex in human HepG2 hepatoma cells. Free Radic Biol Med 2003; 35:636-47. [PMID: 12957656 DOI: 10.1016/s0891-5849(03)00387-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Exogenous arachidonic acid (AA) has been shown to induce the antioxidant manganese superoxide dismutase gene by reactive oxygen species (ROS) derived from AA metabolism and the participation of the p38 mitogen-activated protein kinase (MAPK) pathway in human HepG2 hepatoma cells. The goal of this study was to investigate the effect of AA on the activation of the two redox-sensitive transcription factors AP-1 and NF-kappaB in HepG2 cells. Using electrophoretic mobility shift assays, DNA-binding activities of AP-1 and NF-kappaB were markedly increased in AA-treated HepG2 cells. The c-Jun and c-Fos proteins were identified as components of the AA-induced AP-1 complex and their levels were increased. AA-activated NF-kappaB complex was constituted as a p50 homodimer resulting in a nuclear translocation for this protein only. Moreover, no degradation of IkappaBalpha was observed. These results were contrasted to the interleukin-1beta-activated p50/p65 complex used as a positive control. Using 5,8,11,14-eicosatetraynoic acid and inhibitors of AA metabolism, AP-1 and NF-kappaB activation required the lipoxygenase/cytochrome P450 monooxygenase pathways. In addition, antioxidants inhibited the AA-induced AP-1 and NF-kappaB activation, suggesting a role of ROS released from the AA metabolism. In reporter gene assays, AA induced the transcriptional activity of AP-1 but not that of NF-kappaB. Further investigations showed that the AA-induced transcriptional activity of AP-1 was regulated by protein kinase C and p38 MAPK pathways. These results suggest that the functional AP-1 activated by AA and coupled to that of p38 MAPK pathway may play an important role in response to ROS induced by AA metabolism in HepG2 cells without the involvement of the NF-kappaB pathway.
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Affiliation(s)
- Philippe Bécuwe
- Laboratoire de Biologie Cellulaire du Développement, EA 3446, Université Henri Poincaré-Nancy I, Vandoeuvre-les-Nancy Cedex, France.
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Whitehouse AS, Tisdale MJ. Increased expression of the ubiquitin-proteasome pathway in murine myotubes by proteolysis-inducing factor (PIF) is associated with activation of the transcription factor NF-kappaB. Br J Cancer 2003; 89:1116-22. [PMID: 12966435 PMCID: PMC2376944 DOI: 10.1038/sj.bjc.6601132] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Proteolysis-inducing factor (PIF), isolated from a cachexia-inducing murine tumour, has been shown to stimulate protein breakdown in C(2)C(12) myotubes. The effect was attenuated by the specific proteasome inhibitor lactacystin and there was an elevation of proteasome 'chymotrypsin-like' enzyme activity and expression of 20S proteasome alpha-subunits at concentrations of PIF between 2 and 16 nM. Higher concentrations of PIF had no effect. The action of PIF was attenuated by eicosapentaenoic acid (EPA) (50 microM). At a concentration of 4 nM, PIF induced a transient decrease in IkappaBalpha levels after 30 min incubation, while no effect was seen at 20 nM PIF. The level of IkappaBalpha, an NF-kappaB inhibitory protein, returned to normal after 60 min. Depletion of IkappaBalpha from the cytosol was not seen in myotubes pretreated with EPA, suggesting that the NF-kappaB/IkappaB complex was stabilised. At concentrations between 2 and 8 nM, PIF stimulated an increased nuclear migration of NF-kappaB, which was not seen in myotubes pretreated with EPA. The PIF-induced increase in chymotrypsin-like enzyme activity was also attenuated by the NF-kappaB inhibitor peptide SN50, suggesting that NF-kappaB may be involved in the PIF-induced increase in proteasome expression. The results further suggest that EPA may attenuate protein degradation induced by PIF, at least partly, by preventing NF-kappaB accumulation in the nucleus.
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Affiliation(s)
- A S Whitehouse
- Pharmaceutical Sciences Research Institute, Aston University, Birmingham B4 7ET, UK
| | - M J Tisdale
- Pharmaceutical Sciences Research Institute, Aston University, Birmingham B4 7ET, UK
- Pharmaceutical Sciences Research Institute, Aston University, Birmingham B4 7ET, UK. E-mail:
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Xiong S, She H, Takeuchi H, Han B, Engelhardt JF, Barton CH, Zandi E, Giulivi C, Tsukamoto H. Signaling role of intracellular iron in NF-kappaB activation. J Biol Chem 2003; 278:17646-54. [PMID: 12637578 DOI: 10.1074/jbc.m210905200] [Citation(s) in RCA: 136] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Iron chelators inhibit endotoxin-induced NF-kappaB activation in hepatic macrophages (HMs), suggesting a role for the intracellular chelatable pool of iron in NF-kappaB activation. The present study tested this hypothesis. Analysis of Fe(59)-loaded HMs stimulated with lipopolysaccharide (LPS), revealed a previously unreported, transient rise in intracellular low molecular weight (LMW).Fe(59) complex ([LMW.Fe](i)) at </=2 min returning to the basal level within 15 min. The [LMW.Fe](i) response preceded IkappaB kinase (IKK) (>/=15 min) and NF-kappaB (>/=30 min) activation. Iron chelators (1,2-dimethyl-3-hydroxypyridin-4-one and N,N'-bis-2-hydroxybenzylethylenediamine-N,N'-diacetic acid) abrogated the [LMW.Fe](i) response and IKK and NF-kappaB activation. The [LMW.Fe](i) response was also observed in tumor necrosis factor alpha (TNFalpha)-stimulated HMs and RAW264.7 cells treated with LPS and interferon-gamma but not in primary rat hepatocytes or myofibroblastic cells exposed to LPS or TNFalpha. Both [LMW.Fe](i) response and IKK activation in LPS-stimulated HMs were inhibited by diphenylene iodonium (nonspecific inhibitor for flavin-containing oxidases), l-N(6)-(1-iminoethyl)lysine (selective iNOS inhibitor), and adenoviral-mediated expression of a dominant negative mutant of Rac1 or Cu,Zn-superoxide dismutase, suggesting the role of (.)NO and O(2)() in mediating the iron signaling. In fact, this inhibition was recapitulated by a cell-permeable scavenger of ONOO(-), 5,10,15,20-tetrakis (4-sulfonatophenyl)porphyrinato iron (III) chloride. Conversely, ONOO(-) alone induced both [LMW.Fe](i) response and IKK activation. Finally, direct addition of ferrous iron to cultured HMs activated IKK and NF-kappaB. These results support a novel signaling role for [LMW.Fe](i) in IKK activation, which appears to be induced by ONOO(-) and selectively operative in macrophages.
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Affiliation(s)
- Shigang Xiong
- Department of Pathology and Molecular Microbiology and Immunology, Keck School of Medicine of the University of Southern California, Los Angeles, California 90033, USA
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Fillet M, Bentires-Alj M, Deregowski V, Greimers R, Gielen J, Piette J, Bours V, Merville MP. Mechanisms involved in exogenous C2- and C6-ceramide-induced cancer cell toxicity. Biochem Pharmacol 2003; 65:1633-42. [PMID: 12754099 DOI: 10.1016/s0006-2952(03)00125-4] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Ceramides are important intracellular second messengers that play a role in the regulation of cell growth, differentiation, and programmed cell death. To determine whether ceramides can mediate the apoptosis of HCT116 and OVCAR-3 cancer cells, exogenous C2-, C6-, and C16-ceramides were used to mimic the endogenous lipid increase that follows a large variety of stresses. C2- and C6-ceramides (cell-permeable ceramide analogs), but not C16-ceramide, induced nuclear factor-kappaB (NF-kappaB) DNA-binding, caspase-3 activation, poly(ADP-ribose) polymerase degradation, and mitochondrial cytochrome c release, indicating that apoptosis occurs through the caspase cascade and the mitochondrial pathway. No difference in survival was observed between control cells and cells expressing mutated IkappaBalpha and treated with the permeable ceramides. This suggests that, at least in these cell lines, stable NF-kappaB inhibition did not modify the ceramide-induced cytotoxicity pathway. C6-ceramide also induced a double block in G1 and G2, thus emptying the S phase.
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Affiliation(s)
- Marianne Fillet
- Laboratory of Clinical Chemistry and Human Genetics, CHU B35, University of Liège, Sart-Tilman, 4000, Liège, Belgium.
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16
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Andriollo M, Favier A, Guiraud P. Adriamycin activates NF-kappaB in human lung carcinoma cells by IkappaBalpha degradation. Arch Biochem Biophys 2003; 413:75-82. [PMID: 12706343 DOI: 10.1016/s0003-9861(03)00114-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The aim of this study was to investigate the effect of adriamycin (ADR) in signaling activation of NF-kappaB in ADR-sensitive and -resistant GLC(4) human small-cell lung carcinoma. ADR activated NF-kappaB only in ADR-sensitive GLC(4) cells in a time- and dose-dependant manner by stimulating IkappaBalpha degradation after 4h. Activation of NF-kappaB in response to tumor necrosis factor was intact in both cell lines. Topoisomerase II, a target for a number of chemotherapeutic agents, was depleted in both types of GLC(4) cells after ADR treatment, suggesting the stabilization of transient DNA-topoisomerase II complexes. Another transcription factor, Sp1, was activated by ADR, demonstrating the nonspecificity of NF-kappaB activation in ADR-sensitive GLC(4) cells. These findings indicated that resistance to ADR in ADR-sensitive GLC(4) cells did not involve the NF-kappaB transcription factor.
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Affiliation(s)
- Maud Andriollo
- Laboratoire de Biologie du Stress Oxydant, MNERT JE538 CEA LRC 8M, Faculté de Pharmacie, Université Joseph Fourier, Grenoble, France.
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17
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Sasaki M, Ostanin D, Elrod JW, Oshima T, Jordan P, Itoh M, Joh T, Minagar A, Alexander JS. TNF-alpha -induced endothelial cell adhesion molecule expression is cytochrome P-450 monooxygenase dependent. Am J Physiol Cell Physiol 2003; 284:C422-8. [PMID: 12388057 DOI: 10.1152/ajpcell.00271.2002] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
It is strongly suspected that cytokine-induced gene expression in inflammation is oxidant mediated; however, the intracellular sources of signaling oxidants remain controversial. In inflammatory bowel disease (IBD) proinflammatory cytokines, such as TNF-alpha, trigger gene expression of endothelial adhesion molecules including mucosal addressin cell adhesion molecule-1 (MAdCAM-1). MAdCAM-1 plays an essential role in gut inflammation by governing the infiltration of leukocytes into the intestine. Several groups suggest that endothelial-derived reduced NADP (NADPH) oxidase produces signaling oxidants that control the expression of adhesion molecules (E-selectin, ICAM-1, VCAM-1). In addition to NADPH oxidase, cytochrome P-450 (CYP450) monooxygenases have also been shown to trigger cytokine responses. We found that in high endothelial venular cells (SVEC4-10), multiple inhibitors of CYP450 monooxygenases (SKF-525a, ketoconazole, troleandomycin, itraconazole) attenuated TNF-alpha induction of MAdCAM-1, whereas NADPH oxidase inhibition (PR-39) did not. Conversely, E-selectin, ICAM-1, and VCAM-1 induction requires both NADPH oxidase and CYP450-derived oxidants. We show here that MAdCAM-1 induction may depend exclusively on CYP450-derived oxidants, suggesting that CYP450 blockers might represent a possible novel therapeutic treatment for human IBD.
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Affiliation(s)
- Makoto Sasaki
- Department of Molecular and Cellular Physiology, Louisiana State University Health Sciences Center, Shreveport, Louisiana 71130-3932, USA
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18
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Bentires-Alj M, Barbu V, Fillet M, Chariot A, Relic B, Jacobs N, Gielen J, Merville MP, Bours V. NF-kappaB transcription factor induces drug resistance through MDR1 expression in cancer cells. Oncogene 2003; 22:90-7. [PMID: 12527911 DOI: 10.1038/sj.onc.1206056] [Citation(s) in RCA: 338] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The ubiquitous NF-kappaB transcription factor has been reported to inhibit apoptosis and to induce drug resistance in cancer cells. Drug resistance is the major reason for cancer therapy failure and neoplastic cells often develop multiple mechanisms of drug resistance during tumor progression. We observed that NF-kappaB or P-glycoprotein inhibition in the HCT15 colon cancer cells led to increased apoptotic cell death in response to daunomycin treatment. Interestingly, NF-kappaB inhibition through transfection of a plasmid coding for a mutated IkappaB-alpha inhibitor increased daunomycin cell uptake. Indeed, the inhibition of NF-kappaB reduced mdr1 mRNA and P-glycoprotein expression in HCT15 cells. We identified a consensus NF-kappaB binding site in the first intron of the human mdr1 gene and demonstrated that NF-kappaB complexes could bind with this intronic site. Moreover, NF-kappaB transactivates an mdr1 promoter luciferase construct. Our data thus demonstrate a role for NF-kappaB in the regulation of the mdr1 gene expression in cancer cells and in drug resistance.
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19
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Michiels C, Minet E, Mottet D, Raes M. Regulation of gene expression by oxygen: NF-kappaB and HIF-1, two extremes. Free Radic Biol Med 2002; 33:1231-42. [PMID: 12398931 DOI: 10.1016/s0891-5849(02)01045-6] [Citation(s) in RCA: 159] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Aerobic life is dependent on molecular oxygen for ATP regeneration, but only possible in a narrow range of oxygen concentrations. Increased oxygen tension is toxic through the generation of reactive oxygen species (ROS), while a decrease in oxygen concentration impairs energy availability and, hence, cell viability. Cells have developed strategies to respond to changes in oxygen tension: specific systems detect excessive ROS and hypoxia, leading to the activation of specific transcription factors and expression of appropriate target genes. The aim of this review is to describe how hypoxia-inducible factor-1 (HIF-1) and nuclear factor-kappaB (NF-kappaB) are regulated and what could be the sensors to the changes in oxygen levels. Some of the physiological responses initiated by these transcription factors are also mentioned.
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Affiliation(s)
- Carine Michiels
- Biochemistry and Cellular Biology Laboratory, University of Namur, Belgium.
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20
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Abstract
Kupffer cells, resident macrophages in the liver, play a central role in the homeostatic response to liver injury. Ironically, this defensive mechanism, if dysregulated, also works against the liver in acute and chronic liver damage. Central to this response is activation of nuclear factor-kappaB (NF-kappaB), a redox-sensitive transcription factor that transactivates promoters of many inflammatory genes, including cytokines. Much research has been devoted to identification of upstream signaling for activation of NF-kappaB, but the precise mechanism by which oxidant stress participates in this signaling is yet to be determined. Clues to this key question may be attained through studies on the mechanisms of sustained and/or accentuated NF-kappaB activation in hepatic macrophages in chronic liver diseases. This article reviews the literature on redox regulation of cytokine gene expression by Kupffer cells.
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Affiliation(s)
- Hidekazu Tsukamoto
- USC-UCLA Research Center for Alcoholic Liver and Pancreatic Diseases, Los Angeles, CA 90033, USA.
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21
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Deregowski V, Delhalle S, Benoit V, Bours V, Merville MP. Identification of cytokine-induced nuclear factor-kappaB target genes in ovarian and breast cancer cells. Biochem Pharmacol 2002; 64:873-81. [PMID: 12213581 DOI: 10.1016/s0006-2952(02)01151-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
NF-kappaB is a pleiotropic transcription factor controlling the expression of many genes and viruses. NF-kappaB plays a role in immune response, cellular adhesion or acute phase response. It also inhibits apoptosis and favors cancer cell survival. We studied the expression of genes controlled by NF-kappaB in ovarian and breast adenocarcinoma cancer cells. We stably transfected OVCAR-3 and MCF7 A/Z cells with an expression vector coding for the mutated inhibitor IkappaBalpha, which sequesters NF-kappaB in the cytoplasm. We stimulated control and IkappaBalpha expressing cells with IL-1beta or TNF-alpha and extracted the RNA, which was reverse-transcribed and hybridized to DNA microarrays. Several of the genes identified were not known as NF-kappaB target genes. Among them, we confirmed the differential expression of ephrin-A1 and caveolin-1 by quantitative real-time polymerase chain reaction. Our results showed an NF-kappaB-dependent induction of ephrin-A1 and caveolin-1 mRNAs after stimulation with TNF-alpha and IL-1beta, confirming that NF-kappaB controls target genes implied in tumor angiogenesis and cell transformation.
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Affiliation(s)
- Valérie Deregowski
- Laboratories of Clinical Chemistry and Human Genetics, Center for Molecular and Cellular Therapy, University of Liège, Liège, Belgium
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22
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Potoka DA, Upperman JS, Nadler EP, Wong CT, Zhou X, Zhang XR, Ford HR. NF-kappaB inhibition enhances peroxynitrite-induced enterocyte apoptosis. J Surg Res 2002; 106:7-14. [PMID: 12127801 DOI: 10.1006/jsre.2002.6423] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
BACKGROUND Sustained overproduction of nitric oxide and peroxynitrite (ONOO(-)) in conditions such as necrotizing enterocolitis and inflammatory bowel disease may promote gut barrier failure by inducing enterocyte apoptosis. NF-kappaB is upregulated in the gut during inflammation and, in addition to its proinflammatory effects, may upregulate protective or antiapoptotic factors such as inhibitor of apoptosis proteins (IAPs). We have previously demonstrated that NF-kappaB inhibition increases cytokine-induced enterocyte apoptosis; however, the effect of NF-kappaB on ONOO(-)-induced enterocyte apoptosis is unknown. MATERIALS AND METHODS Rat intestinal epithelial cells (IEC-6) were transfected with the adenoviral vector AdIkappaB or AdlacZ. AdIkappaB contains a mutated form of IkappaB which functions as a superrepressor of NF-kappaB. Cells were then treated with 50 microM ONOO(-) or decomposed ONOO(-). Apoptosis was then determined by flow cytometry with annexin V-FITC and propidium iodide staining. Caspase activation and IAP, Bcl-2, Bad, and Bax expression were examined using Western blot analysis, and NF-kappaB activation was determined via electrophoretic mobility shift assay (EMSA). RESULTS Inhibition of NF-kappaB with AdIkappaB significantly enhanced ONOO(-)-induced apoptosis in IEC-6 cells. ONOO(-) treatment did not activate NF-kappaB in IEC-6 cells as determined by EMSA. There was no difference in IAP, Bcl-2, Bad, and Bax expression between nontransfected, AdlacZ-transfected, and AdIkappaB-transfected cells. Baseline procaspase 3 activation was increased in AdIkappaB-transfected cells. CONCLUSIONS NF-kappaB inhibition enhances ONOO(-)-induced enterocyte apoptosis, suggesting that NF-kappaB upregulates a protective factor. This protective factor does not appear to be an IAP or Bcl-2 family member and may be expressed constitutively, since ONOO(-) did not activate NF-kappaB over baseline levels of activation.
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Affiliation(s)
- Douglas A Potoka
- Department of Surgery, Children's Hospital of Pittsburgh, and University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
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23
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Delhalle S, Deregowski V, Benoit V, Merville MP, Bours V. NF-kappaB-dependent MnSOD expression protects adenocarcinoma cells from TNF-alpha-induced apoptosis. Oncogene 2002; 21:3917-24. [PMID: 12032830 DOI: 10.1038/sj.onc.1205489] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2001] [Revised: 02/26/2002] [Accepted: 03/18/2002] [Indexed: 12/30/2022]
Abstract
NF-kappaB is known to exert a cytoprotective action against TNF-alpha-induced apoptosis. To study the role of NF-kappaB in various TNF-alpha-treated epithelial cell lines, we generated stable transfectants overexpressing a mutated unresponsive form of the IkappaBalpha inhibitor (MT cells). As NF-kappaB prevented TNF-alpha-induced apoptosis in various epithelial cancer cell lines, we searched for NF-kappaB target gene products responsible for this difference of sensitivity. We observed an increased Bcl-X(L) expression level in OVCAR-3 cells compared with OVCAR-3 cells expressing a mutated IkappaBalpha inhibitor (MT cells). Induction of the antioxidant enzyme MnSOD was detected only in TNF-alpha-treated OVCAR, MCF7A/Z and HCT116 cells but not in MT cells. Moreover, reactive oxygen species were involved in TNF-alpha-induced apoptosis, as various antioxidants partially protected these cells from apoptosis. At last, transfection of the MnSOD cDNA in MT cells, which do not express this protein after TNF-alpha stimulation, partially restored resistance to TNF-alpha-induced cell death, as observed by clonogenic assays. However, transfection of the Bcl-X(L) cDNA did not induce any protective effect. Therefore, MnSOD expression is induced by NF-kappaB in epithelial cancer cells in response to TNF-alpha, and is at least partially responsible for their resistance to TNF-alpha-induced apoptosis, presumably through the clearance of death-inducing ROS.
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Affiliation(s)
- Sylvie Delhalle
- Laboratory of Medical Chemistry and Human Genetics, Center for Cellular and Molecular Therapy, CHU B35, Sart-Tilman, University of Liège, 4000 Liège, Belgium
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24
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Ouadrhiri Y, Pilette C, Monteiro RC, Vaerman JP, Sibille Y. Effect of IgA on respiratory burst and cytokine release by human alveolar macrophages: role of ERK1/2 mitogen-activated protein kinases and NF-kappaB. Am J Respir Cell Mol Biol 2002; 26:315-32. [PMID: 11867340 DOI: 10.1165/ajrcmb.26.3.4590] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Human alveolar macrophages (HAM) express FcalphaR receptors for immunoglobulin (Ig)A which could link humoral and cellular branches of lung immunity. Here, we investigate the effects of polymeric (p-IgA) and secretory (S-IgA) IgA interaction with Fc(alpha)R on lipopolysaccharide (LPS)- and phorbol myristate acetate (PMA)-activated respiratory burst and TNF-alpha release by HAM. Activation of HAM with LPS and PMA increases the respiratory burst and TNF-alpha release through activation of the extracellular signal-related protein kinases 1 and 2 (ERK1/2) pathway, because these effects are inhibited by treatment of HAM with PD98059, a selective inhibitor of mitogen-activated protein (MAP)/ERK kinases (MEK) pathway. S-IgA and p-IgA downregulate the LPS-increased respiratory burst in HAM through an inhibition of ERK1/2 activity. In contrast, p- and S-IgA induce an increase in the respiratory burst of PMA-treated HAM. This effect is associated with an upregulation by IgA of the PMA-induced phosphorylation of ERK1/2 and is also inhibited by PD98059. Moreover, p-IgA and S-IgA enhance TNF-alpha release by HAM through an alternative pathway distinct from ERK1/2. Because LPS is known to activate nuclear factor-kappaB (NF-kappaB) in HAM, we evaluate the effect of IgA on NF-kappaB. Treatment of HAM with LPS, p- and S-IgA, but not PMA, induces NF-kappaB activation through IkappaBalpha phosphorylation and subsequent proteolysis. Antioxidants, namely N-acetylcysteine (NAC) and glutathione (GSH), have no effects on IgA-mediated NF-kappaB nuclear translocation and only a minor and late effect on that of LPS, suggesting that reactive oxygen intermediates (ROI) play a minor role in HAM activation through NF-kappaB. TNF-alpha release by LPS-activated HAM is sensitive to NF-kappaB inhibition and only partly to oxidant scavenging. In contrast, TNF-alpha release by IgA-treated HAM is not dependent on oxidants and only partly dependent on NF-kappaB. Our results show a differential HAM regulation by IgA through both dependent and independent modulation of ERK pathway. In addition, IgA activates NF-kappaB and this effect was independent on oxidants. These data may help to understand the role of IgA in both lung protection and inflammation.
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Affiliation(s)
- Youssef Ouadrhiri
- Experimental Medicine Unit, Christian de Duve Institute of Cellular Pathology, University of Louvain, Brussels, Belgium
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25
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Volanti C, Matroule JY, Piette J. Involvement of oxidative stress in NF-kappaB activation in endothelial cells treated by photodynamic therapy. Photochem Photobiol 2002; 75:36-45. [PMID: 11837326 DOI: 10.1562/0031-8655(2002)075<0036:ioosin>2.0.co;2] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
In human endothelial cells ECV 304 and HMEC-1 photosensitized by pyropheophorbide-a methylester (PPME) in sublethal conditions transcription factor Nuclear Factor kappa B (NF-kappaB) activation takes place for several hours. Activated NF-kappaB was functional because it stimulated the transcriptional activation of either a transfected reporter gene or the endogenous gene encoding interleukin (IL)-8. Concomitant with NF-kappaB activation, inhibitor of NF-kappaB alpha (IkappaB alpha) was degraded during photosensitization and IkappaB beta, p100, p105 and IkappaB epsilon were slightly modified. Reactive oxygen species (ROS) were shown to be crucial intermediates in the activation because antioxidants strongly decreased NF-kappaB activation. Using both a fluorescent probe and isotope substitution, it was shown that ROS, and especially singlet oxygen (1O2), were important in the activation process. Because NF-kappaB activation in the presence of ROS was suspected to proceed through a pathway independent of the IkappaB kinases (IKK), we demonstrated that the IKK were indeed not activated by photosensitization but required an intact tyrosine residue at position 42 on IkappaB alpha, suggesting the involvement of a tyrosine kinase in the activation process. This was further reinforced by the demonstration that herbimycin A, a tyrosine kinase inhibitor, prevented NF-kappaB activation by photosensitization but not by TNF alpha, a cytokine known to activate NF-kappaB through an IKK-dependent mechanism.
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Affiliation(s)
- Cédric Volanti
- Laboratory of Virology & Immunology, Institute of Pathology, University of Liège, Belgium
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26
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Zhang WJ, Frei B. Alpha-lipoic acid inhibits TNF-alpha-induced NF-kappaB activation and adhesion molecule expression in human aortic endothelial cells. FASEB J 2001; 15:2423-32. [PMID: 11689467 DOI: 10.1096/fj.01-0260com] [Citation(s) in RCA: 236] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Endothelial activation and monocyte adhesion are initiating steps in atherogenesis thought to be caused in part by oxidative stress. The metabolic thiol antioxidant alpha-lipoic acid has been suggested to be of therapeutic value in pathologies associated with redox imbalances. We investigated the role of (R)-alpha-lipoic acid (LA) vs. glutathione and ascorbic acid in tumor necrosis factor alpha (TNF-alpha) -induced adhesion molecule expression and nuclear factor kappaB (NF-kappaB) signaling in human aortic endothelial cells (HAEC). Preincubation of HAEC for 48 h with LA (0.05-1 mmol/l) dose-dependently inhibited TNF-alpha (10 U/ml) -induced adhesion of human monocytic THP-1 cells, as well as mRNA and protein expression of E-selectin, vascular cell adhesion molecule 1 and intercellular adhesion molecule 1. LA also strongly inhibited TNF-alpha-induced mRNA expression of monocyte chemoattractant protein-1 but did not affect expression of TNF-alpha receptor 1. Furthermore, LA dose-dependently inhibited TNF-alpha-induced IkappaB kinase activation, subsequent degradation of IkappaB, the cytoplasmic NF-kappaB inhibitor, and nuclear translocation of NF-kappaB. In contrast, TNF-alpha-induced NF-kappaB activation and adhesion molecule expression were not affected by ascorbic acid or by manipulating cellular glutathione status with l-2-oxo-4-thiazolidinecarboxylic acid, N-acetyl-l-cysteine, or d,l-buthionine-S,R-sulfoximine. Our data show that clinically relevant concentrations of LA, but neither vitamin C nor glutathione, inhibit adhesion molecule expression in HAEC and monocyte adhesion by inhibiting the IkappaB/NF-kappaB signaling pathway at the level, or upstream, of IkappaB kinase.
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Affiliation(s)
- W J Zhang
- Linus Pauling Institute, Oregon State University, Corvallis, Oregon 97331, USA
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27
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Abstract
In the mammalian lens, intracellular oxidants produced by photo-oxidative processes and exposure to toxic chemicals constitute stresses that produce cellular oxidative damage, result in changes in gene expression, and are causally related to cataract formation. Currently, it is believed that H(2)O(2) is the major oxidant to which the lens is exposed. In this report, we examine the activation and regulation of the oxidant-sensitive transcription factor, NF-kappa B, by H(2)O(2)-mediated oxidative stress in lens epithelial cells. Lens epithelial cells treated with H(2)O(2) demonstrated at 1 h a strong activation of NF-kappa B which returned to basal levels by 2 h. Under proteasome inhibition using both MG132 and lactacystin, H(2)O(2)-mediated activation of NF-kappa B was prevented, implicating the involvement of proteasome degradation of I kappa B proteins as being necessary for this activation. However, Western blot analysis demonstrated no degradation of I kappa B-alpha, -beta, or -epsilon associated with H(2)O(2)-mediated NF-kappa B activation. In comparison, when cells were treated with the cytokine TNF-alpha, NF-kappa B was strongly activated and degradation of both I kappa B-alpha and -beta was observed. These results clearly demonstrate that H(2)O(2)-mediated oxidative stress activates NF-kappa B in lens epithelial cells, which may subsequently lead to changes in gene expression. The results also reveal that different signaling pathways in the activation of NF-kappa B in lens epithelial cells are utilized by H(2)O(2) and TNF-alpha. These different pathways of NF-kappa B activation may be required to effect specific NF-kappa B-dependent gene expression in response to these different stimuli.
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Affiliation(s)
- E J Dudek
- Laboratory for Nutrition and Vision Research, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, MA 02111, USA
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28
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Sandersen C, Bureau F, Turlej R, Fiévez L, Dogné S, Kirschvink N, Lekeux P. p65 Homodimer activity in distal airway cells determines lung dysfunction in equine heaves. Vet Immunol Immunopathol 2001; 80:315-26. [PMID: 11457483 DOI: 10.1016/s0165-2427(01)00329-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Nuclear factor-kappaB (NF-kappaB) activity, which is a key regulator of inflammatory gene expression, is increased in bronchial epithelial cells from horses suffering from heaves (a hypersensitivity-associated inflammatory condition of the lung). To determine whether this increased activity extends to distal airways and to other pulmonary cells, cells recovered by broncho-alveolar lavage (BAL) in healthy and heaves-affected horses were assessed for NF-kappaB activity. NF-kappaB activity was much higher in BAL cells from heaves-affected horses, especially during crisis (disease exacerbation), than in cells from healthy horses. Moreover, the level of NF-kappaB activity found in BAL cells was positively correlated to total lung resistance and to the proportion of neutrophils present in BAL fluid. Finally, prototypical p65-p50 NF-kappaB heterodimers were absent from BAL cells, which mostly contained p65 homodimers. These results (1) show that increased NF-kappaB activity is a general feature of heaves lung; (2) demonstrate the importance of p65 homodimers in neutrophilic inflammation; and (3) suggest that the use of specific NF-kappaB inhibitors could improve lung function in heaves-affected horses.
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Affiliation(s)
- C Sandersen
- Department of Physiology, Faculty of Veterinary Medicine, University of Liège, Bât. B42, Sart Tilman, B-4000 Liège, Belgium
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29
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Okuyama H, Shimahara Y, Kawada N, Seki S, Kristensen DB, Yoshizato K, Uyama N, Yamaoka Y. Regulation of cell growth by redox-mediated extracellular proteolysis of platelet-derived growth factor receptor beta. J Biol Chem 2001; 276:28274-80. [PMID: 11346654 DOI: 10.1074/jbc.m102995200] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Redox-regulated processes are important elements in various cellular functions. Reducing agents, such as N-acetyl-l-cysteine (NAC), are known to regulate signal transduction and cell growth through their radical scavenging action. However, recent studies have shown that reactive oxygen species are not always involved in ligand-stimulated intracellular signaling. Here, we report a novel mechanism by which NAC blocks platelet-derived growth factor (PDGF)-induced signaling pathways in hepatic stellate cells, a fibrogenic player in the liver. Unlike in vascular smooth muscle cells, we found that reducing agents, including NAC, triggered extracellular proteolysis of PDGF receptor-beta, leading to desensitization of hepatic stellate cells toward PDGF-BB. This effect was mediated by secreted mature cathepsin B. In addition, type II transforming growth factor-beta receptor was also down-regulated. Furthermore, these events seemed to cause a dramatic improvement of rat liver fibrosis. These results indicated that redox processes impact the cell's response to growth factors by regulating the turnover of growth factor receptors and that "redox therapy" is promising for fibrosis-related disease.
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Affiliation(s)
- H Okuyama
- Department of Gastroenterological Surgery, Graduate School of Medicine, Kyoto University, Sakyo-ku, Kyoto 606-8397, Japan.
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30
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Bentires-Alj M, Dejardin E, Viatour P, Van Lint C, Froesch B, Reed JC, Merville MP, Bours V. Inhibition of the NF-kappa B transcription factor increases Bax expression in cancer cell lines. Oncogene 2001; 20:2805-13. [PMID: 11420692 DOI: 10.1038/sj.onc.1204343] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2000] [Revised: 09/27/2000] [Accepted: 02/06/2001] [Indexed: 11/09/2022]
Abstract
The NF-kappa B transcription factor has been shown to inhibit apoptosis in several experimental systems. We therefore investigated whether the expression of the Bax proapoptotic protein could be influenced by NF-kappa B activity. Increased Bax protein expression was detected in HCT116, OVCAR-3 and MCF7 cells stably expressing a mutated unresponsive I kappa B-alpha inhibitory protein that blocks NF-kappa B activity. Northern blots showed that bax mRNA expression was increased as a consequence of mutated I kappa B-alpha expression in HCT116 cells. A careful examination of the human bax gene promoter sequence showed three putative binding sites for NF-kappa B, and the kappa B2 site at position -687 could indeed bind NF-kappa B complexes in vitro. Transient transfection of a bax promoter luciferase construct in HCT116 cells showed that NF-kappa B proteins could partially inhibit the transactivation of the bax promoter by p53. Mutations or deletions of the kappa B sites, including kappa B2, indicated that this NF-kappa B-dependent inhibitory effect did not require NF-kappa B DNA-binding, and was thus an indirect effect. However, cotransfection of expression vectors for several known cofactors failed to identify a competition between p53 and NF-kappa B for a transcription coactivator. Our findings thus demonstrate for the first time that NF-kappa B regulates, through an indirect pathway, the bax gene expression.
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Affiliation(s)
- M Bentires-Alj
- Laboratory of Medical Chemistry and Medical Oncology, University of Liège, Belgium
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Renard P, Delaive E, Van Steenbrugge M, Remacle J, Raes M. Is the effect of interleukin-1 on glutathione oxidation in cultured human fibroblasts involved in nuclear factor-kappaB activation? Antioxid Redox Signal 2001; 3:329-40. [PMID: 11396485 DOI: 10.1089/152308601300185269] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Our understanding of the interleukin-1 (IL-1) signaling molecular mechanisms has recently made considerable progress, with the discovery of the IL-1 receptor-associated kinase and the downstream enzymatic cascade that leads to the activation of nuclear factor-kappaB (NF-kappaB). IL-1 signaling and especially NF-kappaB activation are thought to be redox-sensitive, even though the precise nature and the molecular targets of the oxidants/antioxidants involved remain largely unknown. Here, we investigated the possible role of cellular oxidized/reduced glutathione (GSSG/GSH) balance in IL-1 signaling. We describe a quantitative method based on capillary electrophoresis designed to assay both intracellular GSH and GSSG in adhering fibroblasts. This method allows the GSSG/GSH balance to be followed during IL-1 stimulation. Our data show that IL-1 induces rapid and transient oxidation of intracellular glutathione in human fibroblasts. Using various antioxidants, including pyrrolidine dithiocarbamate and curcumin, we were unable to show a direct relationship between this IL-1-induced glutathione oxidation and NF-kappaB activation. Of the five antioxidants tested, only curcumin was able to inhibit IkappaBalpha degradation upstream and, hence, NF-kappaB DNA-binding activity and NF-kappaB-dependent expression of IL-6 downstream.
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Affiliation(s)
- P Renard
- Laboratoire de Biochimie et de Biologie Cellulaire, Facultés Universitaires Notre-Dame de la Paix, Namur, Belgium.
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Abstract
Inflammatory skin diseases account for a large proportion of all skin disorders and constitute a major health problem worldwide. Contact dermatitis, atopic dermatitis, and psoriasis represent the most prevalent inflammatory skin disorders and share a common efferent T-lymphocyte mediated response. Oxidative stress and inflammation have recently been linked to cutaneous damage in T-lymphocyte mediated skin diseases, particularly in contact dermatitis. Insights into the pathophysiology responsible for contact dermatitis can be used to better understand the mechanism of other T-lymphocyte mediated inflammatory skin diseases, and may help to develop novel therapeutic approaches. This review focuses on redox sensitive events in the inflammatory scenario of contact dermatitis, which comprise for example, several kinases, transcription factors, cytokines, adhesion molecules, dendritic cell surface markers, the T-lymphocyte receptor, and the cutaneous lymphocyte-associated antigen (CLA). In vitro and animal studies clearly point to a central role of several distinct but interconnected redox-sensitive pathways in the pathogenesis of contact dermatitis. However, clinical evidence that modulation of the skin's redox state can be used therapeutically to modulate the inflammatory response in contact dermatitis is presently not convincing. The rational for this discrepancy seems to be multi-faceted and complex and will be discussed.
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Affiliation(s)
- J Fuchs
- Department of Dermatology, Medical School, J. W. Goethe University, Frankfurt, Germany
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Bours V, Bonizzi G, Bentires-Alj M, Bureau F, Piette J, Lekeux P, Merville M. NF-kappaB activation in response to toxical and therapeutical agents: role in inflammation and cancer treatment. Toxicology 2000; 153:27-38. [PMID: 11090945 DOI: 10.1016/s0300-483x(00)00302-4] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The NF-kappaB transcription factor is ubiquitously expressed and controls the expression of a large number of genes. Experimental data clearly indicate that NF-kappaB is a major regulator of the inflammatory reaction by controlling the expression of pro-inflammatory molecules in response to cytokines, oxidative stress and infectious agents. We demonstrated that NF-kappaB activation by IL-1beta follows three distinct cell-specific pathways. Moreover, our studies indicated that in one model of inflammatory diseases, horse recurrent airway obstruction (RAO), the extent of NF-kappaB basal activity correlates with pulmonary dysfunction. Another role of NF-kappaB activity protects cancer cells against apoptosis and could participate in the resistance to cancer treatment. However, we did not observe any increased cytotoxicity after treatment with anticancer drugs or TNF-alpha of cells expressing a NF-kappaB inhibitor. Therefore, we can conclude that the inhibition of apoptosis by NF-kappaB is likely to be cell type and stimulus-dependent. Further studies are required to determine whether NF-kappaB could be a target for anticancer treatments.
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Affiliation(s)
- V Bours
- Laboratory of Medical Chemistry and Medical Oncology, Faculty of Medicine, University of Liège, CHU Tour de Pathologie B35, 4000 Sart-Tilman par, 1, Liège, Belgium.
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Schoonbroodt S, Piette J. Oxidative stress interference with the nuclear factor-kappa B activation pathways. Biochem Pharmacol 2000; 60:1075-83. [PMID: 11007944 DOI: 10.1016/s0006-2952(00)00371-3] [Citation(s) in RCA: 185] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
While intracellular redox balance is tightly controlled in many cell types, its modification leads to important cellular changes derived, in part, from a modification of the pattern of gene expression. This modification relies on many transcription factors whose activities are either increased or reduced by a disbalance of the redox environment. Among these transcription factors, nuclear factor-kappa B (NF-kappa B) plays a pivotal role in inducing genes involved in the control of the immune system as well as in the response to injury and infection. Because NF-kappa B can be induced in many cells by a diverse set of stimulating agents, it has been proposed that agents activating it do so by increasing oxidative stress within the cell. However, this model was not found to be universal, since the dependence between NF-kappa B activation and intracellular reactive oxygen species (ROS) generation was only detected in certain cell lines. The origin of this dependency is still unknown, but could very well be situated in a particular kinase or in adaptator molecules of the signaling cascade, leading to inhibitor kappa B alpha (I kappa B alpha phosphorylation. On the other hand, NF-kappa B can be activated by oxidants in many cell types, but this activation is well characterized only in lymphocytes. This activation is distinct from that of classical activators such as proinflammatory cytokines and phorbol esters, because the activation mechanisms appear to converge on a particular tyrosine residue of I kappa B-alpha instead of the two classical N-terminal serines. The nature of the protein kinases or protein phosphatases involved in this process is still undetermined. It will be a challenge in the future to identify the kinases/phosphatases activated by oxidants and to discover why ROS are required in some cells to turn on the transduction pathway leading to NF-kappa B activation by physiological stimuli.
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Affiliation(s)
- S Schoonbroodt
- Laboratory of Virology & Immunology, Institute of Pathology B23, University of Liege, B-4000 Liege, Belgium
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35
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Abstract
In recent years several studies have shown that NF-kappaB might be a very important therapeutic target in the treatment ot various chronic inflammatory, degenerative and tumour diseases. Trace elements play essential roles in the regulation ot cell signaling mechanisms via transcription tactors and a large number of genes. An important aspect of the present review is the description ot the mechanisms by which trace elements might influence transcription factor NF-kappaB. DNA-binding activity of NF-kappaB is regulated by the redox state of the cysteine residue (Gys-62) in the DNA binding domain of the p50 subunit and impaired by different metals (Go, Cr, Ni, Cd, Pb). It has been hypothesised that the broad speciticity of interrelationships between NF-kappaB. AP-1 and various metals results from interactions of metals with specific moieties of transcription factors and IkappaB-kinases, as well as trom the existence of a metal-governed redox system. The hypothetical targets in the NF-kappaB signaling pathway affected by metals are: IkappaB-kinases, IkappaBs, NF-kappaB, proteasome degradation of NF-kappaB, kappaB-sites in DNA. Possibly, this system is required by the cell for adequate regulation ot the transcription machinery in response to changes in intracellular and intranuclear fluxes of metals and radicals and is very ancient evolutionary mechanism of stress adaptation. The role of the NF-kappaB-mediated mechanism in induction or prevention of chronic intlammatory, allergic, degenerative and tumor diseases by zinc, vanadium, manganese, copper, silica, iodine and other trace elements is discussed.
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Affiliation(s)
- A V Kudrin
- Bloelement Center, Laboratory of Trace Elements, Moscow, Russia
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36
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Abstract
Oxygen is crucial to aerobic metabolism, but excesses of oxygen or reactive oxygen species (ROS) can injure cells. This minireview addresses two transcription factors that regulate several cellular responses to oxygen tension. Hypoxia inducible factor-1 (HIF-1) is a heterodimeric protein activated by hypoxia. Levels of HIF-1 are regulated by removal of the HIF-1alpha subunit through ubiquination and proteasomal destruction under normoxic conditions. Hypoxia inhibits the ubiquination of HIF-1alpha, preventing its destruction and allowing it to bind to hypoxia-responsive elements in gene promoter, enhancer, and intronic sequences. HIF-1 induces the expression of the hypoxia responsive genes vascular endothelial growth factor and erythropoietin. Its dysregulation has been implicated in von Hippel-Lindau disease. Nuclear factor kappaB (NFkappaB) is a family of pleotropic, dimeric transcription factors, and has a complex pattern of regulation. Under normoxic conditions, NFkappaB is bound to one of several inhibitory proteins (e.g., IkappaB) that prevent its nuclear translocation. Hyperoxia or elevations of ROS cause the ubiquination and destruction of the inhibitory proteins, freeing NFkappaB and allowing it to bind to target gene promoters. Hyperoxia in cell and animal models and acute lung injury in humans induce the expression of multiple proinflammatory cytokines through NFkappaB-dependent mechanisms. Although HIF-1 and NFkappaB respond to changes in pO(2), the precise nature of the oxygen sensing and transduction pathways is unclear in both cases. Both heme-protein and redox-sensitive mechanisms have been proposed. Improved understanding of oxygen-sensitive gene regulation may suggest targeted therapies for human disease.
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Affiliation(s)
- C T D'Angio
- Strong Children's Research Center, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA
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37
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Schoonbroodt S, Ferreira V, Best-Belpomme M, Boelaert JR, Legrand-Poels S, Korner M, Piette J. Crucial role of the amino-terminal tyrosine residue 42 and the carboxyl-terminal PEST domain of I kappa B alpha in NF-kappa B activation by an oxidative stress. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2000; 164:4292-300. [PMID: 10754328 DOI: 10.4049/jimmunol.164.8.4292] [Citation(s) in RCA: 198] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Activation of transcription factor NF-kappa B involves the signal-dependent degradation of basally phosphorylated inhibitors such as I kappa B alpha. In response to proinflammatory cytokines or mitogens, the transduction machinery has recently been characterized, but the activation mechanism upon oxidative stress remains unknown. In the present work, we provide several lines of evidence that NF-kappa B activation in a T lymphocytic cell line (EL4) by hydrogen peroxide (H2O2) did not involve phosphorylation of the serine residues 32 and 36 in the amino-terminal part of I kappa B alpha. Indeed, mutation of Ser32 and Ser36 blocked IL-1 beta- or PMA-induced NF-kappa B activation, but had no effect on its activation by H2O2. Although I kappa B alpha was phosphorylated upon exposure to H2O2, tyrosine residue 42 and the C-terminal PEST (proline-glutamic acid-serine-threonine) domain played an important role. Indeed, mutation of tyrosine 42 or serine/threonine residues of the PEST domain abolished NF-kappa B activation by H2O2, while it had no effect on activation by IL-1 beta or PMA-ionomycin. This H2O2-inducible phosphorylation was not dependent on I kappa B kinase activation, but could involve casein kinase II, because an inhibitor of this enzyme (5,6-dichloro-1-beta-D-ribofuranosyl-benzimidazole) blocks NF-kappa B activation. H2O2-induced I kappa B alpha phosphorylation was followed by its degradation by calpain proteases or through the proteasome. Taken together, our findings suggest that NF-kappa B activation by H2O2 involves a new mechanism that is totally distinct from those triggered by proinflammatory cytokines or mitogens.
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Affiliation(s)
- S Schoonbroodt
- Laboratory of Virology, Institute of Pathology, University of Liege, Liege, Belgium
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38
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Bureau F, Bonizzi G, Kirschvink N, Delhalle S, Desmecht D, Merville MP, Bours V, Lekeux P. Correlation between nuclear factor-kappaB activity in bronchial brushing samples and lung dysfunction in an animal model of asthma. Am J Respir Crit Care Med 2000; 161:1314-21. [PMID: 10764329 DOI: 10.1164/ajrccm.161.4.9907010] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Asthma is a chronic inflammatory disease of the airways, in which many inflammatory genes are overexpressed. Transcription factor, nuclear factor-kappaB (NF-kappaB), which is thought to control the transcriptional initiation of inflammatory genes, has been poorly investigated in asthma. In the present report, bronchial cells (BCs), recovered by bronchial brushing in healthy and heaves-affected horses (i.e., an animal model of asthma), were assessed for NF-kappaB activity. Small amounts of active NF-kappaB were present in BCs of healthy horses, whereas high levels of NF-kappaB activity was found during crisis (i.e., acute airway obstruction) in all heaves-affected horses. Three weeks after the crisis, the level of NF-kappaB activity found in BCs of heaves-affected horses was highly correlated (p < 0.01) to the degree of residual lung dysfunction. Unexpectedly, active NF- kappaB complexes found in BCs of heaves-affected horses were mainly p65 homodimers, rather than classic p65-p50 heterodimers. At last, intercellular adhesion molecule-1 (ICAM-1) expression paralleled p65 homodimers activity in these cells. These results demonstrate that the kinetics of NF-kappaB activity is strongly related to the course of the disease and confirm the relevance of NF-kappaB as a putative target in asthma therapy. Moreover, uncommon p65 homodimers could transactivate, in BCs, a subset of genes, such as ICAM-1, characteristic of chronic airway inflammation.
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Affiliation(s)
- F Bureau
- Department of Physiology, Faculty of Veterinary Medicine, and Laboratory of Medical Chemistry, Faculty of Medicine, University of Liège, Liège, Belgium.
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Abstract
Reactive oxygen species are produced by all aerobic cells and are widely believed to play a pivotal role in aging as well as a number of degenerative diseases. The consequences of the generation of oxidants in cells does not appear to be limited to promotion of deleterious effects. Alterations in oxidative metabolism have long been known to occur during differentiation and development. Experimental perturbations in cellular redox state have been shown to exert a strong impact on these processes. The discovery of specific genes and pathways affected by oxidants led to the hypothesis that reactive oxygen species serve as subcellular messengers in gene regulatory and signal transduction pathways. Additionally, antioxidants can activate numerous genes and pathways. The burgeoning growth in the number of pathways shown to be dependent on oxidation or antioxidation has accelerated during the last decade. In the discussion presented here, we provide a tabular summary of many of the redox effects on gene expression and signaling pathways that are currently known to exist.
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Affiliation(s)
- R G Allen
- Lankenau Medical Research Center, Thomas Jefferson University, Wynnewood, PA 19106, USA
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40
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Reznikov LL, Shames BD, Barton HA, Selzman CH, Fantuzzi G, Kim SH, Johnson SM, Dinarello CA. Interleukin-1beta deficiency results in reduced NF-kappaB levels in pregnant mice. Am J Physiol Regul Integr Comp Physiol 2000; 278:R263-70. [PMID: 10644648 DOI: 10.1152/ajpregu.2000.278.1.r263] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Interleukin (IL)-1beta-deficient (IL-1beta(-/-)) mice were assessed for cytokine production during pregnancy. A significant reduction in nuclear factor (NF)-kappaB p65 protein content was observed in the uteri and spleens of pregnant IL-1beta(-/-) mice, as demonstrated by immunohistochemistry and Western immunoblot analysis. In addition, electromobility gel shift assay revealed less DNA binding activity of NF-kappaB p65-containing complex in pregnant IL-1beta(-/-) mice. To investigate differences in cytokine production regulated by NF-kappaB, the levels of tumor necrosis factor-alpha, macrophage inflammatory protein-1alpha, and interferon-gamma were measured in the uterine wall, spleen homogenates, and spleen cell cultures obtained from pregnant mice. Endocervical administration of lipopolysaccharide (LPS) increased cytokine levels in both wild-type (IL-1beta(+/+)) and IL-1beta(-/-) animals, but in IL-1beta(-/-) mice this response was 50-75% lower. Splenocytes from nonpregnant mice exhibited decreased LPS-induced cytokine production when primed in vitro with progesterone. This suppression was 25% greater in IL-1beta(-/-) than in IL-1beta(+/+) mice. These data suggest that constitutive NF-kappaB p65 protein synthesis is regulated by IL-1beta, particularly during pregnancy.
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Affiliation(s)
- L L Reznikov
- Division of Infectious Diseases, University of Colorado Health Sciences Center, Denver, Colorado 80262, USA.
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41
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Bonizzi G, Piette J, Merville MP, Bours V. Cell type-specific role for reactive oxygen species in nuclear factor-kappaB activation by interleukin-1. Biochem Pharmacol 2000; 59:7-11. [PMID: 10605929 DOI: 10.1016/s0006-2952(99)00290-7] [Citation(s) in RCA: 121] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The role of reactive oxygen intermediates (ROIs) in nuclear factor-kappaB (NF-kappaB) activation remains a matter of controversy. We have studied whether ROIs played any role in NF-kappaB induction by interleukin-1beta (IL-1beta) in different cell types. Our studies indicated three different pathways. IL-1beta stimulation of lymphoid cells generates ROIs, which are required for IkappaB-alpha degradation and NF-kappaB activation. The source of these ROIs is the 5-lipoxygenase (5-LOX) enzyme. In monocytic cells, ROIs are also produced in response to IL-1beta and necessary for NF-kappaB induction, but their source appears to be the NADPH oxidase complex. Finally, epithelial cells do not generate ROIs after IL-1beta stimulation, but do rapidly activate NF-kappaB. Interestingly, transfection of epithelial cells with the 5-LOX and 5-LOX activating protein expression vectors restored ROI production and ROI-dependent NF-kappaB activation in response to IL-1beta. Our data thus indicate that ROIs are cell type-specific second messengers for NF-kappaB induction by IL-1beta.
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Affiliation(s)
- G Bonizzi
- Laboratory of Medical Chemistry/Medical Oncology, University of Liege, Belgium
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42
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Abstract
The effect of light in combination with a chemical or a natural compound is termed photosensitization, and is known to have multiple cellular effects. Among them, modulation of gene expression is one of the most important, because it directly influences cell adaptation to novel environmental conditions. In previous years, the cis- and trans-acting genetic elements responsible for gene regulation by radiation and photosensitization, in particular, have been well characterized. The molecular mechanisms involved in the cell response revealed that an important control occurs at the transcriptional level and is coordinated by various transcription factors. The extracellular or intracellular changes mediated by photosensitization are detected by several signal transduction networks, allowing cells to mount an appropriated response in term of gene regulation. Mitogen-activated protein kinases (MAPK) and phosphatidylinositol 3-kinases (PI3-K) are among the most thoroughly studied of signal transduction systems and have been shown to participate in a diverse array of cellular programs. In this review, we will show how these cascades can be activated by photosensitization. A third signal type of transduction machinery, which has been shown to be activated by photosensitization, is the one leading to the activation of the Rel/NF-kappaB family of transcription factors. This family includes many members, most of which can form DNA-binding homo- or heterodimers. We will show that molecular mechanisms leading to NF-kappaB activation by photosensitization are initiated by oxidative damage. While the exact nature of the transduction intermediates is still unknown, NF-kappaB activation by radiation followed different pathways from those used by pro-inflammatory cytokines.
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Affiliation(s)
- J Y Matroule
- Laboratory of Virology & Immunology, Institute of Pathology, University of Liege, Belgium
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43
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Bowie A, O'Neill LA. Oxidative stress and nuclear factor-kappaB activation: a reassessment of the evidence in the light of recent discoveries. Biochem Pharmacol 2000; 59:13-23. [PMID: 10605930 DOI: 10.1016/s0006-2952(99)00296-8] [Citation(s) in RCA: 682] [Impact Index Per Article: 28.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Nuclear factor-kappaB (NFKB) is a transcription factor with a pivotal role in inducing genes involved in physiological processes as well as in the response to injury and infection. A model has been proposed whereby the diverse agents that activate NFkappaB do so by increasing oxidative stress within the cell. Activation of NFkappaB involves the phosphorylation and subsequent degradation of an inhibitory protein, IKB, and recently many of the proximal kinases and adaptor molecules involved in this process have been elucidated. Additionally, we now understand in detail the NFkappaB activation pathway from cell membrane to nucleus for interleukin-1 (IL-1) and tumour necrosis factor (TNF). This review revisits the evidence for the oxidative stress model in light of these recent findings, and finds little in the new information to rationalise or justify a central role for oxidative stress in NF-kappaB activation. We demonstrate that much of the evidence for the involvement of oxidative stress is either specific to a stimulus in a particular cell line or open to reinterpretation. In particular, the activation of NFkappaB by hydrogen peroxide is cell-specific and distinct from physiological activators such as IL-1 and TNF, while inhibition by antioxidants, also found to be cell- and stimulus-specific, can involve diverse and unexpected targets which may be distinct from redox modulation. We conclude that in most cases the role of oxidative stress in NF-kappaB activation is at best facilitatory rather than causal, if a role exists at all. In addition, other evidence suggests a role for lipid peroxides in pathways where such a role exists. In future, when a role for oxidative stress in a pathway is postulated, the challenge will be to show which particular kinases or adaptor molecules, if any, are redox-modulated.
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Affiliation(s)
- A Bowie
- Department of Biochemistry, Trinity College, Dublin, Ireland.
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44
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Hoare GS, Marczin N, Chester AH, Yacoub MH. Role of oxidant stress in cytokine-induced activation of NF-kappaB in human aortic smooth muscle cells. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 277:H1975-84. [PMID: 10564154 DOI: 10.1152/ajpheart.1999.277.5.h1975] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The transcription factor nuclear factor-kappaB (NF-kappaB) has been implicated in inflammatory and proliferative vascular mechanisms. Activated NF-kappaB has been documented in human atherosclerotic lesions, and its activation in human vascular smooth muscle cells (SMC) by cytokines has been reported. However, intracellular mechanisms mediating NF-kappaB activation in human SMC are poorly understood. The aim of this study was to explore the potential role of reactive oxygen species and oxidant stress as signaling events in cytokine-induced NF-kappaB activation. Western blot analysis revealed the presence of inhibitory protein I-kappaBalpha in resting human aortic SMC, which was rapidly phosphorylated and degraded on exposure to interleukin-1beta (IL-1beta) followed by NF-kappaB translocation to the nucleus. IL-1beta had no effect on two measures of intracellular oxidant stress, fluorescence generated by the oxidation of 2',7'-dichlorodihydrofluorescin to dichlorofluorescein (DCF) or changes in intracellular sulfhydryl content. N-acetylcysteine (NAC) a membrane-permeant antioxidant, which augmented intracellular sulfhydryl content and inhibited H(2)O(2)-induced DCF fluorescence, had no effect on cytokine-induced NF-kappaB activation. In contrast to NAC, the metal chelators pyrrolidine dithiocarbamate and diethyldithiocarbamate attenuated IL-1beta-induced NF-kappaB activation but had no effect on intracellular sulfhydryl content. Treatment of the cells with the oxidant H(2)O(2) caused an increase in DCF fluorescence and decreased intracellular sulfhydryl content but had no effect on I-kappaBalpha or NF-kappaB. In conclusion, this study suggests that oxidant stress may not play a major role in cytokine-induced activation of NF-kappaB in human aortic SMC and that oxidants may not be primary activators of NF-kappaB in these cells.
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Affiliation(s)
- G S Hoare
- Department of Cardiothoracic Surgery, National Heart and Lung Institute, Imperial College of Science, Harefield, Middlesex UB9 6JH, UK
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45
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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. [DOI: 10.1182/blood.v94.6.1878.418k03_1878_1889] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
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.
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46
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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. [DOI: 10.1182/blood.v94.6.1878] [Citation(s) in RCA: 164] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractTumor 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.
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47
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Manna SK, Kuo MT, Aggarwal BB. Overexpression of gamma-glutamylcysteine synthetase suppresses tumor necrosis factor-induced apoptosis and activation of nuclear transcription factor-kappa B and activator protein-1. Oncogene 1999; 18:4371-82. [PMID: 10439045 DOI: 10.1038/sj.onc.1202811] [Citation(s) in RCA: 117] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Tumor necrosis factor (TNF) is a highly pleiotropic cytokine whose activity is at least partially regulated by the redox status of the cell. The cellular redox status is controlled primarily by glutathione, a major cellular antioxidant, whose synthesis is regulated by the rate-limiting enzyme gamma-glutamylcysteine synthetase (gamma-GCS). In the present report we investigated the effect of gamma-GCS overexpression on the TNF-induced activation of nuclear transcription factors NF-kappa B and AP-1, stress-activated protein kinase/c-Jun amino-terminal kinase (JNK) and apoptosis. Transfection of cells with gamma-GCS cDNA blocked TNF-induced NF-kappa B activation, cytoplasmic I kappa B alpha degradation, nuclear translocation of p65, and NF-kappa B-dependent gene transcription. gamma-GCS overexpression also completely suppressed NF-kappa B activation induced by phorbol ester and okadaic acid, whereas that induced by H2O2, ceramide, and lipopolysaccharide was minimally affected. gamma-GCS also abolished the activation of AP-1 induced by TNF and inhibited TNF-induced activation of JNK and mitogen-activated protein kinase kinase. TNF-mediated cytotoxicity and activation of caspase-3 were both abrogated in gamma-GCS-overexpressing cells. Overall, our results indicate that most of the pleiotropic actions of TNF are regulated by the glutathione-controlled redox status of the cell.
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Affiliation(s)
- S K Manna
- Department of Molecular Oncology, University of Texas MD Anderson Cancer Center, Houston 77030, USA
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Bonizzi G, Piette J, Schoonbroodt S, Merville MP, Bours V. Role of the protein kinase C lambda/iota isoform in nuclear factor-kappaB activation by interleukin-1beta or tumor necrosis factor-alpha: cell type specificities. Biochem Pharmacol 1999; 57:713-20. [PMID: 10037458 DOI: 10.1016/s0006-2952(98)00353-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
It has previously been reported that distinct signaling pathways can lead to nuclear factor (NF)-kappaB activation following stimulation of different cell types with inflammatory cytokines. As the role of atypical protein kinase C (PKC) isoforms in NF-kappaB activation remains a matter of controversy, we investigated whether this role might be cell type-dependent. Immunoblots detected atypical PKC expression in all the analyzed cell lines. The PKC inhibitor calphostin C inhibited NF-kappaB activation by tumor necrosis factor (TNF)-alpha or interleukin (IL)-1beta in Jurkat or NIH3T3 cells but not in MCF7 A/Z cells. Cell transfections with a PKC lambda/iota dominant negative mutant abolished TNF-alpha-induced NF-kappaB-dependent transcription in NIH3T3 and Jurkat cells but not in MCF7 A/Z cells. Similarly, the same mutant blocked NF-kappaB-dependent transactivation after IL-1beta stimulation of NIH3T3 cells, but was ineffective after IL-1beta treatment of MCF7 A/Z cells. In MCF7 A/Z cells, however, the PKC lambda/iota dominant negative mutant could abolish transactivation of an AP-1-dependent reporter plasmid after stimulation with TNF-alpha but not with IL-1beta. These data thus confirm that transduction pathways for NF-kappaB activation after cell stimulation with TNF-alpha or IL-1beta are cell-type specific and that atypical PKC isoforms participate in this pathway in NIH3T3 and Jurkat cells.
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Affiliation(s)
- G Bonizzi
- Laboratory of Medical Chemistry/Medical Oncology, University of Liège, Belgium
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Moon MR, Parikh AA, Pritts TA, Fischer JE, Cottongim S, Szabo C, Salzman AL, Hasselgren PO. Complement component C3 production in IL-1beta-stimulated human intestinal epithelial cells is blocked by NF-kappaB inhibitors and by transfection with ser 32/36 mutant IkappaBalpha. J Surg Res 1999; 82:48-55. [PMID: 10068525 DOI: 10.1006/jsre.1998.5503] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
BACKGROUND Recent studies suggest that interleukin-1beta (IL-1beta) stimulates the production of the acute phase protein complement component C3 in human intestinal epithelial cells. The transcription factor NF-kappaB activates different genes involved in the response to cytokines. It is not known if IL-1beta-induced C3 production in the enterocyte is regulated by NF-kappaB. MATERIALS AND METHODS Cultured Caco-2 cells, a human intestinal epithelial cell line, were treated with one of the NF-kappaB inhibitors, tosyl-lys-chloromethylketone (TLCK), genistein, or pyrrolidine dithiocarbamate (PDTC), or with N-acetyl-leu-leu-norleucinal (LLnL), a proteasome inhibitor known to block the degradation of Ikappabeta, the cytosolic inhibitor of NF-kappaB. Following this treatment, the Caco-2 cells were stimulated with IL-1beta, and C3 levels in the culture medium were measured after 24 h by ELISA. C3 mRNA levels were determined after 4 h by Northern blot analysis. In other experiments, Caco-2 cells were transfected with a mutant IkappaBalpha in which serines 32 and 36 were substituted by alanine. This mutation prevents IkBalpha phosphorylation and subsequent NF-kappaB nuclear translocation. After transfection, the cells were stimulated with IL-1beta, and C3 levels in the culture medium were measured after 24 h. Cytosolic IkappaBalpha was determined by Western blot analysis. RESULTS TLCK, genistein, and LLnL each inhibited IL-1beta-induced C3 production in a dose-dependent fashion. These responses were associated with decreased C3 mRNA levels. In contrast, PDTC did not influence C3 production or C3 mRNA in the Caco-2 cells. Transfection of the Caco-2 cells with the Ser 32/36 mutant IkBalpha resulted in maintained IkappaBalpha levels and decreased IL-beta-induced C3 production. CONCLUSIONS IL-1beta-stimulated C3 production in the enterocyte may be regulated by NF-kappaB.
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Affiliation(s)
- M R Moon
- University of Cincinnati Medical Center, Children's Hospital Medical Center, Cincinnati, Ohio, 45267, USA
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Bonizzi G, Piette J, Schoonbroodt S, Greimers R, Havard L, Merville MP, Bours V. Reactive oxygen intermediate-dependent NF-kappaB activation by interleukin-1beta requires 5-lipoxygenase or NADPH oxidase activity. Mol Cell Biol 1999; 19:1950-60. [PMID: 10022882 PMCID: PMC83988 DOI: 10.1128/mcb.19.3.1950] [Citation(s) in RCA: 185] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We previously reported that the role of reactive oxygen intermediates (ROIs) in NF-kappaB activation by proinflammatory cytokines was cell specific. However, the sources for ROIs in various cell types are yet to be determined and might include 5-lipoxygenase (5-LOX) and NADPH oxidase. 5-LOX and 5-LOX activating protein (FLAP) are coexpressed in lymphoid cells but not in monocytic or epithelial cells. Stimulation of lymphoid cells with interleukin-1beta (IL-1beta) led to ROI production and NF-kappaB activation, which could both be blocked by antioxidants or FLAP inhibitors, confirming that 5-LOX was the source of ROIs and was required for NF-kappaB activation in these cells. IL-1beta stimulation of epithelial cells did not generate any ROIs and NF-kappaB induction was not influenced by 5-LOX inhibitors. However, reintroduction of a functional 5-LOX system in these cells allowed ROI production and 5-LOX-dependent NF-kappaB activation. In monocytic cells, IL-1beta treatment led to a production of ROIs which is independent of the 5-LOX enzyme but requires the NADPH oxidase activity. This pathway involves the Rac1 and Cdc42 GTPases, two enzymes which are not required for NF-kappaB activation by IL-1beta in epithelial cells. In conclusion, three different cell-specific pathways lead to NF-kappaB activation by IL-1beta: a pathway dependent on ROI production by 5-LOX in lymphoid cells, an ROI- and 5-LOX-independent pathway in epithelial cells, and a pathway requiring ROI production by NADPH oxidase in monocytic cells.
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Affiliation(s)
- G Bonizzi
- Laboratory of Medical Chemistry/Medical Oncology, University of Liège, Liège, Belgium
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