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Guo S, Messmer-Blust AF, Wu J, Song X, Philbrick MJ, Shie JL, Rana JS, Li J. Role of A20 in cIAP-2 protection against tumor necrosis factor α (TNF-α)-mediated apoptosis in endothelial cells. Int J Mol Sci 2014; 15:3816-33. [PMID: 24595242 PMCID: PMC3975369 DOI: 10.3390/ijms15033816] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Revised: 01/30/2014] [Accepted: 02/06/2014] [Indexed: 12/13/2022] Open
Abstract
Tumor necrosis factor α (TNF-α) influences endothelial cell viability by altering the regulatory molecules involved in induction or suppression of apoptosis. However, the underlying mechanisms are still not completely understood. In this study, we demonstrated that A20 (also known as TNFAIP3, tumor necrosis factor α-induced protein 3, and an anti-apoptotic protein) regulates the inhibitor of apoptosis protein-2 (cIAP-2) expression upon TNF-α induction in endothelial cells. Inhibition of A20 expression by its siRNA resulted in attenuating expression of TNF-α-induced cIAP-2, yet not cIAP-1 or XIAP. A20-induced cIAP-2 expression can be blocked by the inhibition of phosphatidyl inositol-3 kinase (PI3-K), but not nuclear factor (NF)-κB, while concomitantly increasing the number of endothelial apoptotic cells and caspase 3 activation. Moreover, TNF-α-mediated induction of apoptosis was enhanced by A20 inhibition, which could be rescued by cIAP-2. Taken together, these results identify A20 as a cytoprotective factor involved in cIAP-2 inhibitory pathway of TNF-α-induced apoptosis. This is consistent with the idea that endothelial cell viability is dependent on interactions between inducers and suppressors of apoptosis, susceptible to modulation by TNF-α.
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Affiliation(s)
- Shuzhen Guo
- School of Preclinical Medicine, Beijing University of Chinese Medicine, Beijing 100029, China.
| | - Angela F Messmer-Blust
- CardioVascular Institute, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.
| | - Jiaping Wu
- CardioVascular Institute, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.
| | - Xiaoxiao Song
- CardioVascular Institute, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.
| | - Melissa J Philbrick
- CardioVascular Institute, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.
| | - Jue-Lon Shie
- CardioVascular Institute, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.
| | - Jamal S Rana
- CardioVascular Institute, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.
| | - Jian Li
- CardioVascular Institute, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.
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102
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Involvement of A20 in the molecular switch that activates the non-canonical NF-кB pathway. Sci Rep 2014; 3:2568. [PMID: 24008839 PMCID: PMC3764444 DOI: 10.1038/srep02568] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Accepted: 08/19/2013] [Indexed: 12/13/2022] Open
Abstract
The non-canonical NF-κB pathway is crucial for the immune system. A critical event in activation of the non-canonical pathway is the attenuation of NF-κB-inducing kinase (NIK) degradation, which is promoted by continuous polyubiquitination of NIK catalyzed by the NIK ubiquitin-ligase complex composed of cellular inhibitor of apoptosis protein 1 and 2 (cIAP1/2), TNF receptor-associated factor 2 (TRAF2), and TRAF3. However, the molecular mechanism of stimulation-dependent NIK stabilization remains poorly understood. Here, we show that A20, a ubiquitin-editing enzyme, promotes efficient activation of the non-canonical pathway independent of its catalytic activity. A20 directly binds to cIAP1 through the seventh zinc finger of A20, resulting in dissociation of the TRAF2/TRAF3 interaction, thereby inactivating the ligase complex to stabilize NIK. Given that A20 negatively regulates the canonical pathway, A20 is likely involved in the molecular switch that promotes the transition from canonical to non-canonical activation for proper control of the immune system.
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103
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Tiruppathi C, Soni D, Wang DM, Xue J, Singh V, Thippegowda PB, Cheppudira BP, Mishra RK, Debroy A, Qian Z, Bachmaier K, Zhao YY, Christman JW, Vogel SM, Ma A, Malik AB. The transcription factor DREAM represses the deubiquitinase A20 and mediates inflammation. Nat Immunol 2014; 15:239-47. [PMID: 24487321 PMCID: PMC4005385 DOI: 10.1038/ni.2823] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Accepted: 01/02/2014] [Indexed: 12/14/2022]
Abstract
Here we show that the transcription-repressor DREAM binds to the A20 promoter to repress the expression of A20, the deubiquitinase suppressing inflammatory NF-κB signaling. DREAM-deficient (Dream−/−) mice displayed persistent and unchecked A20 expression in response to endotoxin. DREAM functioned by transcriptionally repressing A20 through binding to downstream regulatory elements (DREs). In contrast, USF1 binding to the DRE-associated E-box domain activated A20 expression in response to inflammatory stimuli. These studies define the critical opposing functions of DREAM and USF1 in inhibiting and inducing A20 expression, respectively, and thereby the strength of NF-κB signaling. Targeting of DREAM to induce USF1-mediated A20 expression is therefore a potential anti-inflammatory strategy in diseases such as acute lung injury associated with unconstrained NF-κB activity.
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Affiliation(s)
- Chinnaswamy Tiruppathi
- Department of Pharmacology and the Center for Lung and Vascular Biology, University of Illinois, Chicago, Illinois, USA
| | - Dheeraj Soni
- Department of Pharmacology and the Center for Lung and Vascular Biology, University of Illinois, Chicago, Illinois, USA
| | - Dong-Mei Wang
- Department of Pharmacology and the Center for Lung and Vascular Biology, University of Illinois, Chicago, Illinois, USA
| | - Jiaping Xue
- Department of Pharmacology and the Center for Lung and Vascular Biology, University of Illinois, Chicago, Illinois, USA
| | - Vandana Singh
- Department of Pharmacology and the Center for Lung and Vascular Biology, University of Illinois, Chicago, Illinois, USA
| | - Prabhakar B Thippegowda
- Department of Pharmacology and the Center for Lung and Vascular Biology, University of Illinois, Chicago, Illinois, USA
| | - Bopaiah P Cheppudira
- Department of Pharmacology and the Center for Lung and Vascular Biology, University of Illinois, Chicago, Illinois, USA
| | - Rakesh K Mishra
- Department of Pharmacology and the Center for Lung and Vascular Biology, University of Illinois, Chicago, Illinois, USA
| | - Auditi Debroy
- Department of Pharmacology and the Center for Lung and Vascular Biology, University of Illinois, Chicago, Illinois, USA
| | - Zhijian Qian
- Department of Hematology/Oncology, College of Medicine, University of Illinois, Chicago, Illinois, USA
| | - Kurt Bachmaier
- Department of Pharmacology and the Center for Lung and Vascular Biology, University of Illinois, Chicago, Illinois, USA
| | - You-Yang Zhao
- Department of Pharmacology and the Center for Lung and Vascular Biology, University of Illinois, Chicago, Illinois, USA
| | - John W Christman
- Department of Pharmacology and the Center for Lung and Vascular Biology, University of Illinois, Chicago, Illinois, USA
| | - Stephen M Vogel
- Department of Pharmacology and the Center for Lung and Vascular Biology, University of Illinois, Chicago, Illinois, USA
| | - Averil Ma
- Department of Medicine, School of Medicine, University of California at San Francisco, San Francisco, California, USA
| | - Asrar B Malik
- Department of Pharmacology and the Center for Lung and Vascular Biology, University of Illinois, Chicago, Illinois, USA
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104
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Villena J, Kitazawa H. Modulation of Intestinal TLR4-Inflammatory Signaling Pathways by Probiotic Microorganisms: Lessons Learned from Lactobacillus jensenii TL2937. Front Immunol 2014; 4:512. [PMID: 24459463 PMCID: PMC3890654 DOI: 10.3389/fimmu.2013.00512] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Accepted: 12/26/2013] [Indexed: 12/21/2022] Open
Abstract
The intestinal mucosa plays a critical role in the host’s interactions with innocuous commensal microbiota and invading pathogenic microorganisms. Intestinal epithelial cells (IECs) and gut associated immune cells recognize the bacterial components via pattern-recognition receptors (PRRs) and are responsible for maintaining tolerance to the large communities of resident luminal bacteria while being also able to mount inflammatory responses against pathogens. Toll-like receptors (TLRs) are a major class of PRRs that are present on IECs and immune cells which are involved in the induction of both tolerance and inflammation. A growing body of experimental and clinical evidence supports the therapeutic and preventive application of probiotics for several gastrointestinal inflammatory disorders in which TLRs exert a significant role. This review aims to summarize the current knowledge of the beneficial effects of probiotic microorganisms with the capacity to modulate the immune system (immunobiotics) in the regulation of intestinal inflammation in pigs, which are very important as both livestock and human model. Especially we discuss the role of TLRs, their signaling pathways, and their negative regulators in both the inflammatory intestinal injury and the beneficial effects of immunobiotics in general, and Lactobacillus jensenii TL2937 in particular. This review article emphasizes the cellular and molecular interactions of immunobiotics with IECs and immune cells through TLRs and their application for improving animal and human health.
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Affiliation(s)
- Julio Villena
- Immunobiotics Research Group , Tucuman , Argentina ; Laboratory of Immunobiotechnology, Reference Centre for Lactobacilli (CERELA-CONICET) , Tucuman , Argentina
| | - Haruki Kitazawa
- Food and Feed Immunology Group, Laboratory of Animal Products Chemistry, Department of Science of Food Function and Health, Graduate School of Agricultural Science, Tohoku University , Sendai , Japan
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105
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Wertz I, Dixit V. A20--a bipartite ubiquitin editing enzyme with immunoregulatory potential. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 809:1-12. [PMID: 25302362 DOI: 10.1007/978-1-4939-0398-6_1] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Proper regulation of inflammation is essential for combating pathogen invasion and maintaining homeostasis. While hyporesponsive hosts succumb to infections, unchecked inflammatory reactions promote debilitating and fatal conditions including septic shock, autoimmune disease, atherosclerosis, graft rejection, and cancer. Pathogens, host immune cell ligands, and pro-inflammatory cytokines such as Tumor Necrosis Factor-alpha (TNF-alpha), Interleukin-1-beta (IL1-beta), and Lipopolysaccharide (LPS) induce an array of inflammatory responses by activating a variety of cell types. Although much is known about how inflammatory responses are initiated and sustained, less is known about how inflammation is attenuated to maintain a homeostatic balance. In this chapter, we review the key role played by A20, also referred to as Tumor Necrosis Factor Inducible Protein 3 (TNFAIP3) in restoring cellular homeostasis through NF-kappaB inhibition, and discuss the molecular basis for its potent anti-inflammatory function as related to the ubiquitin editing and ubiquitin binding activities of A20.
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106
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Yoon JH, Cho YJ, Park HH. Structure of the TRAF4 TRAF domain with a coiled-coil domain and its implications for the TRAF4 signalling pathway. ACTA ACUST UNITED AC 2013; 70:2-10. [DOI: 10.1107/s139900471302333x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Accepted: 08/19/2013] [Indexed: 01/10/2023]
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107
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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: 238] [Impact Index Per Article: 19.8] [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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108
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109
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Waters JP, Pober JS, Bradley JR. Tumour necrosis factor in infectious disease. J Pathol 2013; 230:132-47. [PMID: 23460469 DOI: 10.1002/path.4187] [Citation(s) in RCA: 101] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2013] [Revised: 02/15/2013] [Accepted: 02/23/2013] [Indexed: 12/12/2022]
Abstract
TNF signals through two distinct receptors, designated TNFR1 and TNFR2, which initiate diverse cellular effects that include cell survival, activation, differentiation, and proliferation and cell death. These cellular responses can promote immunological and inflammatory responses that eradicate infectious agents, but can also lead to local tissue injury at sites of infection and harmful systemic effects. Defining the molecular mechanisms involved in TNF responses, the effects of natural and experimental genetic diversity in TNF signalling and the effects of therapeutic blockade of TNF has increased our understanding of the key role that TNF plays in infectious disease.
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Affiliation(s)
- John P Waters
- Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge, UK
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110
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An anti-inflammatory role of A20 zinc finger protein during trauma combined with endotoxin challenge. J Surg Res 2013; 185:717-25. [PMID: 24055365 DOI: 10.1016/j.jss.2013.06.031] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Revised: 05/27/2013] [Accepted: 06/13/2013] [Indexed: 11/24/2022]
Abstract
OBJECTIVE To investigate the anti-inflammatory role of A20 zinc finger protein during trauma combined with bacterial endotoxin challenge and explore the molecular mechanism underlying this process. METHODS Traumatic bone impact injury was induced in the hind limbs of mice. One hour after injury, mice were challenged with purified gram-negative bacterial endotoxins, lipopolysaccharides (LPSs), by tail vein injection. Effects on A20 messenger RNA and protein expressions were assessed by reverse transcription-polymerase chain reaction and Western blotting, respectively. A20 recombinant adenoviruses, full-length (pAdA20 1-775) and N-terminal mutant (pAdA20 1-367), were constructed and used to infect RAW264.7 macrophage cells or mice. Responses in the tumor necrosis factor α (TNF-α)-nuclear factor κB (NF-κB) signaling pathway were evaluated by enzyme-linked immunosorbent assay (for TNF-α) and electrophoretic mobility shift assay (for NF-κB). RESULTS Trauma combined with LPS challenge and LPS challenge alone dramatically promoted A20 expression in mouse liver tissues. LPS challenge increased A20 messenger RNA levels appreciably in RAW264.7 cells within 1 h. Full-length A20 recombinant adenoviruses (pAdA20 1-775) suppressed NF-κB activity and TNF-α expression and protected against liver damage and animal death otherwise induced by trauma combined with LPS challenge. CONCLUSIONS A20 zinc finger protein plays an anti-inflammatory role and protects against liver injury associated with trauma combined with LPS challenge.
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111
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Garg AV, Ahmed M, Vallejo AN, Ma A, Gaffen SL. The deubiquitinase A20 mediates feedback inhibition of interleukin-17 receptor signaling. Sci Signal 2013; 6:ra44. [PMID: 23737552 DOI: 10.1126/scisignal.2003699] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The proinflammatory cytokine interleukin-17 (IL-17) is the signature cytokine of the T helper 17 (TH17) subset of CD4(+) T cells, and antibodies targeting IL-17 or the IL-17 receptor (IL-17R) show clinical efficacy in several autoimmune diseases. Although important for protective immunity against microorganisms, IL-17 causes collateral damage in inflammatory settings. TNFAIP3 encodes the deubiquitinase A20 and is genetically linked to numerous autoimmune syndromes. A20, a potent inhibitor of tumor necrosis factor-α signaling, removes ubiquitin from signaling intermediates upstream of nuclear factor κB (NF-κB), thereby dampening NF-κB-mediated inflammation. We demonstrated that IL-17 stimulates TNFAIP3 expression. Enhanced IL-17-mediated induction of genes encoding proinflammatory factors, including IL-6 and various chemokines, occurred upon knockdown of A20 with short inhibitory RNA or in A20(-/-) cells. A20 associated with the E3 ubiquitin ligase TRAF6 (tumor necrosis factor receptor-associated factor 6) in an IL-17-dependent manner and restricted the IL-17-dependent activation of NF-κB and mitogen-activated protein kinases. A20 interacted directly with the distal domain of IL-17RA, a previously defined inhibitory domain. Together, these data describe a mechanism of restraining IL-17 signaling and reveal an aspect of A20 activity that may help to explain its role in autoimmunity in humans.
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Affiliation(s)
- Abhishek V Garg
- Division of Rheumatology and Clinical Immunology, Department of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA
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112
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Dimerization and ubiquitin mediated recruitment of A20, a complex deubiquitinating enzyme. Immunity 2013; 38:896-905. [PMID: 23602765 DOI: 10.1016/j.immuni.2013.03.008] [Citation(s) in RCA: 131] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Accepted: 03/27/2013] [Indexed: 01/10/2023]
Abstract
A20 is an anti-inflammatory protein linked to multiple human autoimmune diseases and lymphomas. A20 possesses a deubiquitinating motif and a zinc finger, ZF4, that binds ubiquitin and supports its E3 ubiquitin ligase activity. To understand how these activities mediate A20's physiological functions, we generated two lines of gene-targeted mice, abrogating either A20's deubiquitinating activity (Tnfaip3(OTU) mice) or A20's ZF4 (Tnfaip3(ZF4) mice). Both Tnfaip3(OTU) and Tnfaip3(ZF4) mice exhibited increased responses to TNF and sensitivity to colitis. A20's C103 deubiquitinating motif restricted both K48- and K63-linked ubiquitination of receptor interacting protein 1 (RIP1). A20's ZF4 was required for recruiting A20 to ubiquitinated RIP1. A20(OTU) proteins and A20(ZF4) proteins complemented each other to regulate RIP1 ubiquitination and NFκB signaling normally in compound mutant Tnfaip3(OTU/ZF4) cells. This complementation involved homodimerization of A20 proteins, and we have defined an extensive dimerization interface in A20. These studies reveal how A20 proteins collaborate to restrict TNF signaling.
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113
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Tomosada Y, Villena J, Murata K, Chiba E, Shimazu T, Aso H, Iwabuchi N, Xiao JZ, Saito T, Kitazawa H. Immunoregulatory effect of bifidobacteria strains in porcine intestinal epithelial cells through modulation of ubiquitin-editing enzyme A20 expression. PLoS One 2013; 8:e59259. [PMID: 23555642 PMCID: PMC3608626 DOI: 10.1371/journal.pone.0059259] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Accepted: 02/13/2013] [Indexed: 12/20/2022] Open
Abstract
Background We previously showed that evaluation of anti-inflammatory activities of lactic acid bacteria in porcine intestinal epithelial (PIE) cells is useful for selecting potentially immunobiotic strains. Objective The aims of the present study were: i) to select potentially immunomodulatory bifidobacteria that beneficially modulate the Toll-like receptor (TLR)-4-triggered inflammatory response in PIE cells and; ii) to gain insight into the molecular mechanisms involved in the anti-inflammatory effect of immunobiotics by evaluating the role of TLR2 and TLR negative regulators in the modulation of proinflammatory cytokine production and activation of mitogen-activated protein kinase (MAPK) and nuclear factor-κB (NF-κB) pathways in PIE cells. Results Bifidobacteria longum BB536 and B. breve M-16V strains significantly downregulated levels of interleukin (IL)-8, monocyte chemotactic protein (MCP)-1 and IL-6 in PIE cells challenged with heat-killed enterotoxigenic Escherichia coli. Moreover, BB536 and M-16V strains attenuated the proinflammatory response by modulating the NF-κB and MAPK pathways. In addition, our findings provide evidence for a key role for the ubiquitin-editing enzyme A20 in the anti-inflammatory effect of immunobiotic bifidobacteria in PIE cells. Conclusions We show new data regarding the mechanism involved in the anti-inflammatory effect of immunobiotics. Several strains with immunoregulatory capabilities used a common mechanism to induce tolerance in PIE cells. Immunoregulatory strains interacted with TLR2, upregulated the expression of A20 in PIE cells, and beneficially modulated the subsequent TLR4 activation by reducing the activation of MAPK and NF-κB pathways and the production of proinflammatory cytokines. We also show that the combination of TLR2 activation and A20 induction can be used as biomarkers to screen and select potential immunoregulatory bifidobacteria strains.
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Affiliation(s)
- Yohsuke Tomosada
- Food and Feed Immunology Group, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
| | - Julio Villena
- Food and Feed Immunology Group, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
- Laboratory of Clinical and Experimental Biochemistry, Reference Centre for Lactobacilli (CERELA-CONICET), Tucuman, Argentina
| | - Kozue Murata
- Food and Feed Immunology Group, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
| | - Eriko Chiba
- Food and Feed Immunology Group, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
| | - Tomoyuki Shimazu
- Laboratory of Animal Breeding and Genetics, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
| | - Hisashi Aso
- Cell Biology Laboratory, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
| | - Noriyuki Iwabuchi
- Food Science and Technology Institute, Morinaga Milk Industry Co. Ltd, Zama, Kanagawa, Japan
| | - Jin-zhong Xiao
- Food Science and Technology Institute, Morinaga Milk Industry Co. Ltd, Zama, Kanagawa, Japan
| | - Tadao Saito
- Food and Feed Immunology Group, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
| | - Haruki Kitazawa
- Food and Feed Immunology Group, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
- * E-mail:
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114
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Sakakibara S, Espigol-Frigole G, Gasperini P, Uldrick TS, Yarchoan R, Tosato G. A20/TNFAIP3 inhibits NF-κB activation induced by the Kaposi's sarcoma-associated herpesvirus vFLIP oncoprotein. Oncogene 2013; 32:1223-32. [PMID: 22525270 PMCID: PMC3594048 DOI: 10.1038/onc.2012.145] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2011] [Revised: 03/02/2012] [Accepted: 03/05/2012] [Indexed: 12/29/2022]
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) K13/vFLIP (viral Flice-inhibitory protein) induces transcription of numerous genes through NF-κB activation, including pro-inflammatory cytokines, which contribute to the pathogenesis of Kaposi's sarcoma (KS). In this study, we report that KSHV vFLIP induces the expression of the NF-κB regulatory proteins A20, ABIN-1 and ABIN-3 (A20-binding NF-κB inhibitors) in primary human endothelial cells, and that KS spindle cells express A20 in KS tissue. In reporter assays, A20 strongly impaired vFLIP-induced NF-κB activation in 293T cells, but ABIN-1 and ABIN-3 did not. Mutational analysis established that the C-terminal domain (residues 427-790) is critical for A20 modulation of NF-κB, but the ubiquitin-editing OTU (ovarian tumor) domain is not. In functional assays, A20 inhibited vFLIP-induced expression of the chemokine IP-10, reduced vFLIP-induced cell proliferation and increased IKK1 protein levels. Thus, we demonstrate that A20 negatively regulates NF-κB activation directly induced by KSHV vFLIP. By attenuating excessive and prolonged vFLIP-induced NF-κB activation that could be harmful to KSHV-infected cells, A20 likely has an important role in the pathogenesis of KSHV-associated diseases, in which vFLIP is expressed.
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Affiliation(s)
- S Sakakibara
- Laboratory of Cellular Oncology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - G Espigol-Frigole
- Laboratory of Cellular Oncology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - P Gasperini
- Laboratory of Cellular Oncology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - TS Uldrick
- HIV and AIDS Malignancy Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - R Yarchoan
- HIV and AIDS Malignancy Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - G Tosato
- Laboratory of Cellular Oncology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
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115
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Abstract
Dendritic cells (DCs) are specialized sentinels responsible for coordinating adaptive immunity. This function is dependent upon coupled sensitivity to environmental signs of inflammation and infection to cellular maturation-the programmed alteration of DC phenotype and function to enhance immune cell activation. Although DCs are thus well equipped to respond to pathogens, maturation triggers are not unique to infection. Given that immune cells are exquisitely sensitive to the biological functions of DCs, we now appreciate that multiple layers of suppression are required to restrict the environmental sensitivity, cellular maturation, and even life span of DCs to prevent aberrant immune activation during the steady state. At the same time, steady-state DCs are not quiescent but rather perform key functions that support homeostasis of numerous cell types. Here we review these functions and molecular mechanisms of suppression that control steady-state DC maturation. Corruption of these steady-state operatives has diverse immunological consequences and pinpoints DCs as potent drivers of autoimmune and inflammatory disease.
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Affiliation(s)
- Gianna Elena Hammer
- Department of Medicine, University of California, San Francisco, California 94143
| | - Averil Ma
- Department of Medicine, University of California, San Francisco, California 94143
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116
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Scheinman R. NF-κB and Rheumatoid Arthritis: Will Understanding Genetic Risk Lead to a Therapeutic Reward? ACTA ACUST UNITED AC 2013; 4:93-110. [PMID: 24678426 DOI: 10.1615/forumimmundisther.2013008408] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
NF-κB has long been known to play an important role in autoimmune diseases such as rheumatoid arthritis (RA). Indeed, as our understanding of how NF-κB is utilized has increased, we have been hard put to find a process not associated with this transcription factor family in some way. However, new data originating, in part, from genome-wide association studies have demonstrated that very specific alterations in components of the NF-κB pathway are sufficient to confer increased risk of developing disease. Here we review the data which have identified specific components of the NF-κB pathway, and consider what is known of their mechanisms of action and how these mechanisms might play into the disease process. In addition, the use of genetic information to predict RA is considered.
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Affiliation(s)
- Robert Scheinman
- University of Colorado Denver, School of Pharmacy, Department of Pharmaceutical Sciences, Aurora, CO 80045;
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117
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TNFAIP3 gene polymorphisms confer risk for Behcet’s disease in a Chinese Han population. Hum Genet 2012; 132:293-300. [DOI: 10.1007/s00439-012-1250-7] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Accepted: 11/05/2012] [Indexed: 01/01/2023]
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118
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The role of A20 in the pathogenesis of lymphocytic malignancy. Cancer Cell Int 2012; 12:44. [PMID: 23134590 PMCID: PMC3518150 DOI: 10.1186/1475-2867-12-44] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2012] [Accepted: 11/04/2012] [Indexed: 01/15/2023] Open
Abstract
Autoimmune phenomena were identified in many different cases of hematological diseases and solid tumors, which may be due to alterations in the expression and function of the NF-κB signaling pathway. Recently, a number of studies have shown that the deletion or mutation of A20, a negative regulator of NF-κB, is frequently found in lymphomas, suggesting that it may be a linker between the altered immune response and leukemogenesis. The aim of this review is to summarize current findings of the A20 biological functions and its molecular mechanism as a tumor suppressor and immune regulator. The identification of A20 mutations and deletions in lymphocytic malignancy and the predictive significance of these aberrations are also reviewed.
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119
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A20: linking a complex regulator of ubiquitylation to immunity and human disease. NATURE REVIEWS. IMMUNOLOGY 2012. [PMID: 23059429 DOI: 10.1038/nri3313)] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
A20 (also known as TNFAIP3) is a potent anti-inflammatory signalling molecule that restricts multiple intracellular signalling cascades. Recent studies in three general areas have converged to highlight the clinical and biological importance of A20. First, human genetic studies have strongly linked polymorphisms and mutations in the gene encoding A20 to inflammatory, autoimmune and malignant diseases. Second, studies in gene-targeted mice have revealed that A20 regulates multiple immune cell functions and prevents experimental diseases that closely mimic human conditions. Third, biochemical studies have unveiled complex mechanisms by which A20 regulates ubiquitin-dependent nuclear factor-κB and cell-survival signals. Taken together, these studies are revealing the importance of A20-mediated regulation of ubiquitin-dependent signalling in human disease.
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120
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A20: linking a complex regulator of ubiquitylation to immunity and human disease. Nat Rev Immunol 2012; 12:774-85. [PMID: 23059429 DOI: 10.1038/nri3313] [Citation(s) in RCA: 415] [Impact Index Per Article: 31.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
A20 (also known as TNFAIP3) is a potent anti-inflammatory signalling molecule that restricts multiple intracellular signalling cascades. Recent studies in three general areas have converged to highlight the clinical and biological importance of A20. First, human genetic studies have strongly linked polymorphisms and mutations in the gene encoding A20 to inflammatory, autoimmune and malignant diseases. Second, studies in gene-targeted mice have revealed that A20 regulates multiple immune cell functions and prevents experimental diseases that closely mimic human conditions. Third, biochemical studies have unveiled complex mechanisms by which A20 regulates ubiquitin-dependent nuclear factor-κB and cell-survival signals. Taken together, these studies are revealing the importance of A20-mediated regulation of ubiquitin-dependent signalling in human disease.
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121
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Abstract
The nuclear factor-κB (NF-κB) pathway is a critical regulator of innate and adaptive immunity. Noncanonical K63-linked polyubiquitination plays a key regulatory role in NF-κB signaling pathways by functioning as a scaffold to recruit kinase complexes containing ubiquitin-binding domains. Ubiquitination is balanced by deubiquitinases that cleave polyubiquitin chains and oppose the function of E3 ubiquitin ligases. Deubiquitinases therefore play an important role in the termination of NF-κB signaling and the resolution of inflammation. In this review, we focus on NF-κB regulation by deubiquitinases with an emphasis on A20 and CYLD. Deubiquitinases and the ubiquitin/proteasome components that regulate NF-κB may serve as novel therapeutic targets for inflammatory diseases and cancer.
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Affiliation(s)
- Edward W Harhaj
- Department of Microbiology and Immunology, Sylvester Comprehensive Cancer Center, The University of Miami, Miller School of Medicine, Miami, FL, USA
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122
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Zinc and regulation of inflammatory cytokines: implications for cardiometabolic disease. Nutrients 2012; 4:676-94. [PMID: 22852057 PMCID: PMC3407988 DOI: 10.3390/nu4070676] [Citation(s) in RCA: 182] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2012] [Revised: 06/08/2012] [Accepted: 06/25/2012] [Indexed: 12/17/2022] Open
Abstract
In atherosclerosis and diabetes mellitus, the concomitant presence of low-grade systemic inflammation and mild zinc deficiency highlights a role for zinc nutrition in the management of chronic disease. This review aims to evaluate the literature that reports on the interactions of zinc and cytokines. In humans, inflammatory cytokines have been shown both to up- and down-regulate the expression of specific cellular zinc transporters in response to an increased demand for zinc in inflammatory conditions. The acute phase response includes a rapid decline in the plasma zinc concentration as a result of the redistribution of zinc into cellular compartments. Zinc deficiency influences the generation of cytokines, including IL-1β, IL-2, IL-6, and TNF-α, and in response to zinc supplementation plasma cytokines exhibit a dose-dependent response. The mechanism of action may reflect the ability of zinc to either induce or inhibit the activation of NF-κB. Confounders in understanding the zinc-cytokine relationship on the basis of in vitro experimentation include methodological issues such as the cell type and the means of activating cells in culture. Impaired zinc homeostasis and chronic inflammation feature prominently in a number of cardiometabolic diseases. Given the high prevalence of zinc deficiency and chronic disease globally, the interplay of zinc and inflammation warrants further examination.
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123
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Suppression of the interferon and NF-κB responses by severe fever with thrombocytopenia syndrome virus. J Virol 2012; 86:8388-401. [PMID: 22623799 DOI: 10.1128/jvi.00612-12] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease characterized by high fever, thrombocytopenia, multiorgan dysfunction, and a high fatality rate between 12 and 30%. It is caused by SFTS virus (SFTSV), a novel Phlebovirus in family Bunyaviridae. Although the viral pathogenesis remains largely unknown, hemopoietic cells appear to be targeted by the virus. In this study we report that human monocytes were susceptible to SFTSV, which replicated efficiently, as shown by an immunofluorescence assay and real-time reverse transcription-PCR. We examined host responses in the infected cells and found that antiviral interferon (IFN) and IFN-inducible proteins were induced upon infection. However, our data also indicated that downregulation of key molecules such as mitochondrial antiviral signaling protein (MAVS) or weakened activation of interferon regulatory factor (IRF) and NF-κB responses may contribute to a restricted innate immunity against the infection. NSs, the nonstructural protein encoded by the S segment, suppressed the beta interferon (IFN-β) and NF-κB promoter activities, although NF-κB activation appears to facilitate SFTSV replication in human monocytes. NSs was found to be associated with TBK1 and may inhibit the activation of downstream IRF and NF-κB signaling through this interaction. Interestingly, we demonstrated that the nucleoprotein (N), also encoded by the S segment, exhibited a suppressive effect on the activation of IFN-β and NF-κB signaling as well. Infected monocytes, mainly intact and free of apoptosis, may likely be implicated in persistent viral infection, spreading the virus to the circulation and causing primary viremia. Our findings provide the first evidence in dissecting the host responses in monocytes and understanding viral pathogenesis in humans infected with a novel deadly Bunyavirus.
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Bao B, Thakur A, Li Y, Ahmad A, Azmi AS, Banerjee S, Kong D, Ali S, Lum LG, Sarkar FH. The immunological contribution of NF-κB within the tumor microenvironment: a potential protective role of zinc as an anti-tumor agent. BIOCHIMICA ET BIOPHYSICA ACTA 2012; 1825:160-72. [PMID: 22155217 PMCID: PMC3811120 DOI: 10.1016/j.bbcan.2011.11.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Revised: 11/14/2011] [Accepted: 11/19/2011] [Indexed: 12/16/2022]
Abstract
Over decades, cancer treatment has been mainly focused on targeting cancer cells and not much attention to host tumor microenvironment. Recent advances suggest that the tumor microenvironment requires in-depth investigation for understanding the interactions between tumor cell biology and immunobiology in order to optimize therapeutic approaches. Tumor microenvironment consists of cancer cells and tumor associated reactive fibroblasts, infiltrating non-cancer cells, secreted soluble factors or molecules, and non-cellular support materials. Tumor associated host immune cells such as Th(1), Th(2), Th17, regulatory cells, dendritic cells, macrophages, and myeloid-derived suppressor cells are major components of the tumor microenvironment. Accumulating evidence suggests that these tumor associated immune cells may play important roles in cancer development and progression. However, the exact functions of these cells in the tumor microenvironment are poorly understood. In the tumor microenvironment, NF-κB plays an important role in cancer development and progression because this is a major transcription factor which regulates immune functions within the tumor microenvironment. In this review, we will focus our discussion on the immunological contribution of NF-κB in tumor associated host immune cells within the tumor microenvironment. We will also discuss the potential protective role of zinc, a well-known immune response mediator, in the regulation of these immune cells and cancer cells in the tumor microenvironment especially because zinc could be useful for conditioning the tumor microenvironment toward innovative cancer therapy.
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Affiliation(s)
- Bin Bao
- Department of Pathology, Karmanos Cancer Institute, Wayne State University, Detroit, MI, USA
| | - Archana Thakur
- Department of Oncology, Karmanos Cancer Institute, Wayne State University, Detroit, MI, USA
| | - Yiwei Li
- Department of Pathology, Karmanos Cancer Institute, Wayne State University, Detroit, MI, USA
| | - Aamir Ahmad
- Department of Pathology, Karmanos Cancer Institute, Wayne State University, Detroit, MI, USA
| | - Asfar S. Azmi
- Department of Pathology, Karmanos Cancer Institute, Wayne State University, Detroit, MI, USA
| | - Sanjeev Banerjee
- Department of Pathology, Karmanos Cancer Institute, Wayne State University, Detroit, MI, USA
| | - Dejuan Kong
- Department of Pathology, Karmanos Cancer Institute, Wayne State University, Detroit, MI, USA
| | - Shadan Ali
- Department of Pathology, Karmanos Cancer Institute, Wayne State University, Detroit, MI, USA
| | - Lawrence G. Lum
- Department of Oncology, Karmanos Cancer Institute, Wayne State University, Detroit, MI, USA
- Department of Immunology and Microbiology, Karmanos Cancer Institute, Wayne State University, Detroit, MI, USA
| | - Fazlul H. Sarkar
- Department of Pathology, Karmanos Cancer Institute, Wayne State University, Detroit, MI, USA
- Department of Oncology, Karmanos Cancer Institute, Wayne State University, Detroit, MI, USA
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125
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Wang Y, Paszek P, Horton CA, Yue H, White MR, Kell DB, Muldoon MR, Broomhead DS. A systematic survey of the response of a model NF-κB signalling pathway to TNFα stimulation. J Theor Biol 2012; 297:137-47. [PMID: 22202812 PMCID: PMC3315024 DOI: 10.1016/j.jtbi.2011.12.014] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2010] [Revised: 12/11/2011] [Accepted: 12/13/2011] [Indexed: 11/27/2022]
Abstract
White's lab established that strong, continuous stimulation with tumour necrosis factor-α (TNFα) can induce sustained oscillations in the subcellular localisation of the transcription factor nuclear factor κB (NF-κB). But the intensity of the TNFα signal varies substantially, from picomolar in the blood plasma of healthy organisms to nanomolar in diseased states. We report on a systematic survey using computational bifurcation theory to explore the relationship between the intensity of TNFα stimulation and the existence of sustained NF-κB oscillations. Using a deterministic model developed by Ashall et al. in 2009, we find that the system's responses to TNFα are characterised by a supercritical Hopf bifurcation point: above a critical intensity of TNFα the system exhibits sustained oscillations in NF-kB localisation. For TNFα below this critical value, damped oscillations are observed. This picture depends, however, on the values of the model's other parameters. When the values of certain reaction rates are altered the response of the signalling pathway to TNFα stimulation changes: in addition to the sustained oscillations induced by high-dose stimulation, a second oscillatory regime appears at much lower doses. Finally, we define scores to quantify the sensitivity of the dynamics of the system to variation in its parameters and use these scores to establish that the qualitative dynamics are most sensitive to the details of NF-κB mediated gene transcription.
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Affiliation(s)
- Yunjiao Wang
- Manchester Interdisciplinary Biocentre, University of Manchester, Manchester M1 7DN, UK
- School of Mathematics, University of Manchester, M13 9PL, UK
- Mathematical Bioscience Institute, Ohio State University, Columbus, OH 43210, USA
| | - Pawel Paszek
- Faculty of Life Sciences, University of Manchester, M13 9PL, UK
| | - Caroline A. Horton
- Center for Cell Imaging, School of Biological Sciences, Bioscience Research Building, Crown Street, Liverpool L69 7ZB, UK
| | - Hong Yue
- Department of Electronic and Electrical Engineering, University of Strathclyde, Graham Hills Building, Glasgow G1 1XW, Scotland, UK
| | - Michael R.H. White
- Faculty of Life Sciences, University of Manchester, M13 9PL, UK
- Center for Cell Imaging, School of Biological Sciences, Bioscience Research Building, Crown Street, Liverpool L69 7ZB, UK
| | - Douglas B. Kell
- Manchester Interdisciplinary Biocentre, University of Manchester, Manchester M1 7DN, UK
- School of Chemistry, University of Manchester, Manchester M1 7DN, UK
| | - Mark R. Muldoon
- Manchester Interdisciplinary Biocentre, University of Manchester, Manchester M1 7DN, UK
- School of Mathematics, University of Manchester, M13 9PL, UK
| | - David S. Broomhead
- Manchester Interdisciplinary Biocentre, University of Manchester, Manchester M1 7DN, UK
- School of Mathematics, University of Manchester, M13 9PL, UK
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126
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Shembade N, Harhaj EW. Regulation of NF-κB signaling by the A20 deubiquitinase. Cell Mol Immunol 2012; 9:123-30. [PMID: 22343828 DOI: 10.1038/cmi.2011.59] [Citation(s) in RCA: 174] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The NF-κB transcription factor is a central mediator of inflammatory and innate immune signaling pathways. Activation of NF-κB is achieved by K63-linked polyubiquitination of key signaling molecules which recruit kinase complexes that in turn activate the IκB kinase (IKK). Ubiquitination is a highly dynamic process and is balanced by deubiquitinases that cleave polyubiquitin chains and terminate downstream signaling events. The A20 deubiquitinase is a critical negative regulator of NF-κB and inflammation, since A20-deficient mice develop uncontrolled and spontaneous multi-organ inflammation. Furthermore, specific polymorphisms in the A20 genomic locus predispose humans to autoimmune disease. Recent studies also indicate that A20 is an important tumor suppressor that is inactivated in B-cell lymphomas. Therefore, targeting A20 may form the basis of novel therapies for autoimmune disease and lymphomas.
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Affiliation(s)
- Noula Shembade
- Department of Microbiology and Immunology, Sylvester Comprehensive Cancer Center, The University of Miami, Miller School of Medicine, Miami, FL 33136, USA
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127
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Skaug B, Chen J, Du F, He J, Ma A, Chen ZJ. Direct, noncatalytic mechanism of IKK inhibition by A20. Mol Cell 2012; 44:559-71. [PMID: 22099304 DOI: 10.1016/j.molcel.2011.09.015] [Citation(s) in RCA: 205] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2011] [Revised: 06/28/2011] [Accepted: 09/06/2011] [Indexed: 01/30/2023]
Abstract
A20 is a potent anti-inflammatory protein that inhibits NF-κB, and A20 dysfunction is associated with autoimmunity and B cell lymphoma. A20 harbors a deubiquitination enzyme domain and can employ multiple mechanisms to antagonize ubiquitination upstream of NEMO, a regulatory subunit of the IκB kinase complex (IKK). However, direct evidence of IKK inhibition by A20 is lacking, and the inhibitory mechanism remains poorly understood. Here we show that A20 can directly impair IKK activation without deubiquitination or impairment of ubiquitination enzymes. We find that polyubiquitin binding by A20, which is largely dependent on A20's seventh zinc-finger motif (ZnF7), induces specific binding to NEMO. Remarkably, this ubiquitin-induced recruitment of A20 to NEMO is sufficient to block IKK phosphorylation by its upstream kinase TAK1. Our results suggest a noncatalytic mechanism of IKK inhibition by A20 and a means by which polyubiquitin chains can specify a signaling outcome.
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Affiliation(s)
- Brian Skaug
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9148, USA
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128
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Induction of protective genes leads to islet survival and function. J Transplant 2011; 2011:141898. [PMID: 22220267 PMCID: PMC3246756 DOI: 10.1155/2011/141898] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2011] [Accepted: 09/01/2011] [Indexed: 12/16/2022] Open
Abstract
Islet transplantation is the most valid approach to the treatment of type 1 diabetes. However, the function of transplanted islets is often compromised since a large number of β cells undergo apoptosis induced by stress and the immune rejection response elicited by the recipient after transplantation. Conventional treatment for islet transplantation is to administer immunosuppressive drugs to the recipient to suppress the immune rejection response mounted against transplanted islets. Induction of protective genes in the recipient (e.g., heme oxygenase-1 (HO-1), A20/tumor necrosis factor alpha inducible protein3 (tnfaip3), biliverdin reductase (BVR), Bcl2, and others) or administration of one or more of the products of HO-1 to the donor, the islets themselves, and/or the recipient offers an alternative or synergistic approach to improve islet graft survival and function. In this perspective, we summarize studies describing the protective effects of these genes on islet survival and function in rodent allogeneic and xenogeneic transplantation models and the prevention of onset of diabetes, with emphasis on HO-1, A20, and BVR. Such approaches are also appealing to islet autotransplantation in patients with chronic pancreatitis after total pancreatectomy, a procedure that currently only leads to 1/3 of transplanted patients being diabetes-free.
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129
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Chang EJ, Ha J, Kang SS, Lee ZH, Kim HH. AWP1 binds to tumor necrosis factor receptor-associated factor 2 (TRAF2) and is involved in TRAF2-mediated nuclear factor-kappaB signaling. Int J Biochem Cell Biol 2011; 43:1612-20. [DOI: 10.1016/j.biocel.2011.07.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2011] [Revised: 07/15/2011] [Accepted: 07/20/2011] [Indexed: 10/17/2022]
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130
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Yang X, Luo C, Cai J, Powell DW, Yu D, Kuehn MH, Tezel G. Neurodegenerative and inflammatory pathway components linked to TNF-α/TNFR1 signaling in the glaucomatous human retina. Invest Ophthalmol Vis Sci 2011; 52:8442-54. [PMID: 21917936 DOI: 10.1167/iovs.11-8152] [Citation(s) in RCA: 149] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE This study aimed to determine retinal proteomic alterations in human glaucoma, with particular focus on links to TNF-α/TNFR1 signaling. METHODS Human retinal protein samples were obtained from 20 donors with (n = 10) or without (n = 10) glaucoma. Alterations in protein expression were individually analyzed by quantitative LC-MS/MS. Quantitative Western blot analysis with cleavage or phosphorylation site-specific antibodies was used for data validation, and cellular localization of selected proteins was determined by immunohistochemical analysis of the retina in an additional group of glaucomatous human donor eyes (n = 38) and nonglaucomatous controls (n = 30). RESULTS Upregulated retinal proteins in human glaucoma included a number of downstream adaptor/interacting proteins and protein kinases involved in TNF-α/TNFR1 signaling. Bioinformatic analysis of the high-throughput data established extended networks of diverse functional interactions with death-promoting and survival-promoting pathways and mediation of immune response. Upregulated pathways included death receptor-mediated caspase cascade, mitochondrial dysfunction, endoplasmic reticulum stress, calpains leading to apoptotic cell death, NF-κB and JAK/STAT pathways, and inflammasome-assembly mediating inflammation. Interestingly, retinal expression pattern of a regulator molecule, TNFAIP3, exhibited prominent variability between individual samples, and methylation of cytosine nucleotides in the TNFAIP3 promoter was found to be correlated with this variability among glaucomatous donors. CONCLUSIONS Findings of this study reveal a number of proteins upregulated in the glaucomatous human retina that exhibit many links to TNF-α/TNFR1 signaling. By highlighting various signaling molecules and regulators involved in cell death and immune response pathways and by correlating proteomic findings with epigenetic alterations, these findings provide a framework motivating further research.
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Affiliation(s)
- Xiangjun Yang
- Department of Ophthalmology and Visual Sciences, University of Louisville School of Medicine, Louisville, Kentucky 40202, USA
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131
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Charan RA, Hanson R, Clemens PR. Deubiquitinating enzyme A20 negatively regulates NF-κB signaling in skeletal muscle in mdx mice. FASEB J 2011; 26:587-95. [PMID: 22012122 DOI: 10.1096/fj.11-189829] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Duchenne muscular dystrophy (DMD) is caused by the lack of a functional dystrophin protein that results in muscle fiber membrane disruption and, ultimately, degeneration. Regeneration of muscle fibers fails progressively, and muscle tissue is replaced with connective tissue. As a result, DMD causes progressive limb muscle weakness and cardiac and respiratory failure. The absence of dystrophin from muscle fibers triggers the chronic activation of the nuclear factor of kappa B (NF-κB). Chronic activation of NF-κB in muscle leads to infiltration of macrophages, up-regulation of the ubiquitin-proteosome system, and down-regulation of the helix-loop-helix muscle regulatory factor, MyoD. These processes, triggered by NF-κB activation, promote muscle degeneration and failure of muscle regeneration. A20 (TNFAIP3) is a critical negative regulator of NF-κB. In this study, we characterize the role of A20 in regulating NF-κB activation in skeletal muscle, identifying a novel role in muscle regeneration. A20 is highly expressed in regenerating muscle fibers, and knockdown of A20 impairs muscle differentiation in vitro, which suggests that A20 expression is critically important for regeneration of dystrophic muscle tissue. Furthermore, down-regulation of the classic pathway of NF-κB activation is associated with up-regulation of the alternate pathway in regenerating muscle fibers, suggesting a mechanism by which A20 promotes muscle regeneration. These results demonstrate the important role of A20 in muscle fiber repair and suggest the potential of A20 as a therapeutic target to ameliorate the pathology and clinical symptoms of DMD.
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Affiliation(s)
- Rakshita A Charan
- Neurology Service, Department of Veterans Affairs Medical Center, Pittsburgh, Pennsylvania, USA
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132
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TGF-β1 re-programs TLR4 signaling in L. donovani infection: enhancement of SHP-1 and ubiquitin-editing enzyme A20. Immunol Cell Biol 2011; 90:640-54. [PMID: 21968712 DOI: 10.1038/icb.2011.80] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Visceral leishmaniasis (VL), caused by Leishmania donovani, is a major health concern in India. It represents T-helper type 2 (Th2) bias of cytokines in active state and Th1 bias at cure. However, the role of the parasite in regulating Toll-like receptor (TLR)-mediated macrophage activation in VL patients remains elusive. In this report, we demonstrated that later stages of L. donovani infection rendered tolerance to macrophages, leading to incapability for the production of inflammatory cytokines like tumor necrosis factor (TNF)-α and interleukin (IL)-1β in response to TLR stimulation. Overexpression of transforming growth factor (TGF)-β(1), but not IL-10, resulted in suppressed lipopolysaccharide (LPS)-induced production of TNF-α and downregulation of TLR4 expression in L. donovani-infected macrophages. Recombinant human (rh)TGF-β(1) markedly enhanced tyrosine phosphatase (Src homology region 2 domain-containing phosphatase-1) activity, but inhibited IL-1 receptor-activated kinase (IRAK)-1 activation. Addition of neutralizing TGF-β(1) antibody reversed these effects, and thus suggesting the pivotal role of TGF-β(1) in promoting refractoriness for LPS in macrophages. Surprisingly, the use of a tyrosine phosphatase inhibitor (sodium orthovanadate, Na(3)VO(4)) promoted IRAK-1 activation, confirming the negative inhibitory role of tyrosine phosphatase in macrophage activation. Furthermore, rhTGF-β(1) induced tolerance in infected macrophages by reducing inhibitory protein (IκBα) degradation in a time-dependent manner. In addition, short interfering RNA studies proved that overexpression of A20 ubiquitin-editing protein complex induced inhibitory activity of TGF-β(1) on LPS-mediated nuclear factor-κB activation. Thus, these findings suggest that TGF-β(1) promotes overexpression of A20 through tyrosine phosphatase activity that ensures transient activation of inflammatory signaling pathways in macrophages in active L. donovani infection.
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133
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Verhelst K, Carpentier I, Beyaert R. Regulation of TNF-induced NF-κB activation by different cytoplasmic ubiquitination events. Cytokine Growth Factor Rev 2011; 22:277-86. [DOI: 10.1016/j.cytogfr.2011.11.002] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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134
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Terry AJ, Chaplain MAJ. Spatio-temporal modelling of the NF-κB intracellular signalling pathway: the roles of diffusion, active transport, and cell geometry. J Theor Biol 2011; 290:7-26. [PMID: 21907212 DOI: 10.1016/j.jtbi.2011.08.036] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2011] [Revised: 07/01/2011] [Accepted: 08/27/2011] [Indexed: 11/26/2022]
Abstract
The nuclear factor kappa B (NF-κB) intracellular signalling pathway is central to many stressful, inflammatory, and innate immune responses. NF-κB proteins themselves are transcription factors for hundreds of genes. Experiments have shown that the NF-κB pathway can exhibit oscillatory dynamics-a negative feedback loop causes oscillatory nuclear-cytoplasmic translocation of NF-κB. Given that cell size and shape are known to influence intracellular signal transduction, we consider a spatio-temporal model of partial differential equations for the NF-κB pathway, where we model molecular movement by diffusion and, for several key species including NF-κB, by active transport as well. Through numerical simulations we find values for model parameters such that sustained oscillatory dynamics occur. Our spatial profiles and animations bear a striking resemblance to experimental images and movie clips employing fluorescent fusion proteins. We discover that oscillations in nuclear NF-κB may occur when active transport is across the nuclear membrane only, or when no species are subject to active transport. However, when active transport is across the nuclear membrane and NF-κB is additionally actively transported through the cytoplasm, oscillations are lost. Hence transport mechanisms in a cell will influence its response to activation of its NF-κB pathway. We also demonstrate that sustained oscillations in nuclear NF-κB are somewhat robust to changes in the shape of the cell, or the shape, location, and size of its nucleus, or the location of ribosomes. Yet if the cell is particularly flat or the nucleus sufficiently small, then oscillations are lost. Thus the geometry of a cell may partly determine its response to NF-κB activation. The NF-κB pathway is known to be constitutively active in several human cancers. Our spatially explicit modelling approach will allow us, in future work, to investigate targeted drug therapy of tumours.
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Affiliation(s)
- Alan J Terry
- Division of Mathematics, University of Dundee, Dundee, Scotland, UK.
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135
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HCV infection and B-cell lymphomagenesis. Adv Hematol 2011; 2011:835314. [PMID: 21789042 PMCID: PMC3140784 DOI: 10.1155/2011/835314] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2011] [Revised: 06/14/2011] [Accepted: 06/17/2011] [Indexed: 12/31/2022] Open
Abstract
Hepatitis C virus (HCV) has been recognized as a major cause of chronic liver diseases worldwide. It has been suggested that HCV infects not only hepatocytes but also mononuclear lymphocytes including B cells that express the CD81 molecule, a putative HCV receptor. HCV infection of B cells is the likely cause of B-cell dysregulation disorders such as mixed cryoglobulinemia, rheumatoid factor production, and B-cell lymphoproliferative disorders that may evolve into non-Hodgkin's lymphoma (NHL). Epidemiological data indicate an association between HCV chronic infection and the occurrence of B-cell NHL, suggesting that chronic HCV infection is associated at least in part with B-cell lymphomagenesis. In this paper, we aim to provide an overview of recent literature, including our own, to elucidate a possible role of HCV chronic infection in B-cell lymphomagenesis.
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136
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Abstract
NF-κB transcription factors are critical regulators of immunity, stress responses, apoptosis and differentiation. A variety of stimuli coalesce on NF-κB activation, which can in turn mediate varied transcriptional programs. Consequently, NF-κB-dependent transcription is not only tightly controlled by positive and negative regulatory mechanisms but also closely coordinated with other signaling pathways. This intricate crosstalk is crucial to shaping the diverse biological functions of NF-κB into cell type- and context-specific responses.
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137
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Abstract
Primary mediastinal large B-cell lymphoma (PMBCL) is a recognized non-Hodgkin lymphoma entity with unique pathologic, clinical, and molecular characteristics distinct from those of other diffuse large B-cell lymphomas. Immunohistochemical characterization and molecular studies strongly suggest that PMBCL is of germinal center or postgerminal center origin. Pivotal gene expression profiling work defined major deregulated pathway activities that overlap with Hodgkin lymphoma and prompted a more detailed analysis of candidate genes. In particular, the nuclear factor-κB and the Janus Kinase-Signal Transducer and Activator of Transcription signaling pathways are targeted by multiple genomic hits, and constitutive activity of both pathways can be considered molecular hallmark alterations of PMBCL. Moreover, data are emerging giving unique insight into remodeling of the epigenome that affects transcriptional regulation of a multitude of genes. More recently, the tumor microenvironment of PMBCL has shifted into focus based on a number of gene perturbations altering expression of surface molecules that contribute to immune escape. These findings highlight the importance of immune privilege in the pathogenesis of PMBCL and suggest that disrupting crosstalk between the tumor cells and the microenvironment might be a rational new therapeutic target in conjunction with traditional treatment strategies.
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138
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van Loo G, Beyaert R. Negative regulation of NF-κB and its involvement in rheumatoid arthritis. Arthritis Res Ther 2011; 13:221. [PMID: 21639951 PMCID: PMC3218875 DOI: 10.1186/ar3324] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The transcription factor NF-κB plays crucial roles in the regulation of inflammation and mmune responses, and inappropriate NF-κB activity has been linked with many autoimmune and inflammatory diseases, including rheumatoid arthritis. Cells employ a multilayered control system to keep NF-κB signalling in check, including a repertoire of negative feedback regulators ensuring termination of NF-κB responses. Here we will review various negative regulatory mechanisms that have evolved to control NF-κB signalling and which have been implicated in the pathogenesis of rheumatoid arthritis.
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Affiliation(s)
- Geert van Loo
- Department for Molecular Biomedical Research, Unit of Molecular Signal Transduction in Inflammation, VIB, B-9052 Ghent, Belgium.
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139
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Wang Y, Paszek P, Horton CA, Kell DB, White MRH, Broomhead DS, Muldoon MR. Interactions among oscillatory pathways in NF-kappa B signaling. BMC SYSTEMS BIOLOGY 2011; 5:23. [PMID: 21291535 PMCID: PMC3050740 DOI: 10.1186/1752-0509-5-23] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/26/2010] [Accepted: 02/03/2011] [Indexed: 12/24/2022]
Abstract
BACKGROUND Sustained stimulation with tumour necrosis factor alpha (TNF-alpha) induces substantial oscillations--observed at both the single cell and population levels--in the nuclear factor kappa B (NF-kappa B) system. Although the mechanism has not yet been elucidated fully, a core system has been identified consisting of a negative feedback loop involving NF-kappa B (RelA:p50 hetero-dimer) and its inhibitor I-kappa B-alpha. Many authors have suggested that this core oscillator should couple to other oscillatory pathways. RESULTS First we analyse single-cell data from experiments in which the NF-kappa B system is forced by short trains of strong pulses of TNF-alpha. Power spectra of the ratio of nuclear-to-cytoplasmic concentration of NF-kappa B suggest that the cells' responses are entrained by the pulsing frequency. Using a recent model of the NF-kappa B system due to Caroline Horton, we carried out extensive numerical simulations to analyze the response frequencies induced by trains of pulses of TNF-alpha stimulation having a wide range of frequencies and amplitudes. These studies suggest that for sufficiently weak stimulation, various nonlinear resonances should be observable. To explore further the possibility of probing alternative feedback mechanisms, we also coupled the model to sinusoidal signals with a wide range of strengths and frequencies. Our results show that, at least in simulation, frequencies other than those of the forcing and the main NF-kappa B oscillator can be excited via sub- and superharmonic resonance, producing quasiperiodic and even chaotic dynamics. CONCLUSIONS Our numerical results suggest that the entrainment phenomena observed in pulse-stimulated experiments is a consequence of the high intensity of the stimulation. Computational studies based on current models suggest that resonant interactions between periodic pulsatile forcing and the system's natural frequencies may become evident for sufficiently weak stimulation. Further simulations suggest that the nonlinearities of the NF-kappa B feedback oscillator mean that even sinusoidally modulated forcing can induce a rich variety of nonlinear interactions.
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Affiliation(s)
- Yunjiao Wang
- Mathematical Biosciences Institute, The Ohio State University, Jennings Hall, Columbus, Ohio 43210, USA
- School of Mathematics, Alan Turing Building, University of Manchester, Manchester M13 9PL, UK
| | - Pawel Paszek
- Centre for Cell Imaging, School of Biological Sciences, Bioscience Research Building, Crown Street, Liverpool, L69 7ZB, UK
| | - Caroline A Horton
- Centre for Cell Imaging, School of Biological Sciences, Bioscience Research Building, Crown Street, Liverpool, L69 7ZB, UK
| | - Douglas B Kell
- School of Chemistry and The Manchester Interdisciplinary Biocentre, University of Manchester, 131 Princess Street, Manchester M1 7DN, UK
| | - Michael RH White
- Centre for Cell Imaging, School of Biological Sciences, Bioscience Research Building, Crown Street, Liverpool, L69 7ZB, UK
| | - David S Broomhead
- School of Mathematics, Alan Turing Building, University of Manchester, Manchester M13 9PL, UK
| | - Mark R Muldoon
- School of Mathematics, Alan Turing Building, University of Manchester, Manchester M13 9PL, UK
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140
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Abstract
Nuclear factor-kappa B (NF-κB) is a critical regulator of multiple biological functions including innate and adaptive immunity and cell survival. Activation of NF-κB is tightly regulated to preclude chronic signaling that may lead to persistent inflammation and cancer. Ubiquitination of key signaling molecules by E3 ubiquitin ligases has emerged as an important regulatory mechanism for NF-κB signaling. Deubiquitinases (DUBs) counteract E3 ligases and therefore play a prominent role in the downregulation of NF-κB signaling and homeostasis. Understanding the mechanisms of NF-κB downregulation by specific DUBs such as A20 and CYLD may provide therapeutic opportunities for the treatment of chronic inflammatory diseases and cancer.
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Affiliation(s)
- Edward W Harhaj
- Department of Microbiology and Immunology, Sylvester Comprehensive Cancer Center, The University of Miami, Miller School of Medicine, 1550 NW 10 Avenue, Miami, FL 33136, USA
| | - Vishva M Dixit
- Department of Physiological Chemistry, Genentech Inc., 1 DNA Way, South San Francisco, CA 94080, USA
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141
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Phosphorylation-dependent association of the G4-1/G5PR regulatory subunit with IKKβ negatively modulates NF-κB activation through recruitment of protein phosphatase 5. Biochem J 2010; 433:187-96. [DOI: 10.1042/bj20100247] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The transcription factor NF-κB (nuclear factor κB) co-ordinates various gene expressions in response to diverse signals and is a critical regulator of inflammation and innate immunity. Several negative regulators of NF-κB have been identified as downstream targets of NF-κB and function as a feedback control of NF-κB activation. A few protein phosphatases have also been shown to inactivate NF-κB activation. However, little is known about how protein phosphatases detect and respond to NF-κB activation. In the present study, we report a regulatory subunit of PP5 (protein phosphatase 5), G4-1, that physically interacts with IKKβ [IκB (inhibitor of NF-κB) kinase β] and negatively regulates NF-κB activation. The association of G4-1 with IKKβ depends on the kinase activity of IKKβ. Mapping of the G4-1-binding domain of IKKβ reveals that the serine-rich domain in the C-terminus of IKKβ is required for G4-1 binding. When seven autophosphorylated serine residues in this domain were mutated to alanine, the mutant form of IKKβ lost its ability to bind G4-1 and was more potent than the wild-type kinase to activate NF-κB. Knockdown of G4-1 enhanced TNFα (tumour necrosis factor α)-induced NF-κB activity, and knockdown of PP5 totally abolished the inhibitory activity of G4-1 on NF-κB activation. The results of the present study suggest that G4-1 functions as an adaptor to recruit PP5 to the phosphorylated C-terminus of activated IKKβ and to down-regulate the activation of IKKβ.
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142
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Won M, Park KA, Byun HS, Sohn KC, Kim YR, Jeon J, Hong JH, Park J, Seok JH, Kim JM, Yoon WH, Jang IS, Shen HM, Liu ZG, Hur GM. Novel anti-apoptotic mechanism of A20 through targeting ASK1 to suppress TNF-induced JNK activation. Cell Death Differ 2010; 17:1830-41. [PMID: 20448643 PMCID: PMC7386326 DOI: 10.1038/cdd.2010.47] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The zinc-finger protein A20 has crucial physiological functions as a dual inhibitor of nuclear factor-κB (NF-κB) activation and apoptosis in tumor necrosis factor (TNF) receptor 1 signaling pathway. Although the molecular basis for the anti-NF-κB function of A20 has been well elucidated, the anti-apoptotic function of A20 is largely unknown. Here, we report a novel mechanism underlying the anti-apoptotic function of A20: A20 blocks TNF-induced apoptosis through suppression of c-jun N-terminal kinase (JNK) by targeting apoptosis signal-regulating kinase1 (ASK1). First, the ectopic expression of A20 drastically inhibits TNF-induced JNK activation and apoptosis in multiple cell types including those deficient of NF-κB activation. Unexpectedly, the blunting effect of A20 on TNF-induced JNK activation is not mediated by affecting the TNFR1 signaling complex formation. Instead, A20 interacts with ASK1, an important MAPKK kinase in the JNK signaling cascade. More importantly, overexpression of wild-type A20, but not of mutant A20 (ZnF4; C624A, C627A), promotes degradation of the ASK1 through the ubiquitin-proteasome system. Taken together, the results from this study reveal a novel anti-apoptotic mechanism of A20 in TNF signaling pathway: A20 binds to ASK1 and mediates ASK1 degradation, leading to suppression of JNK activation and eventually blockage of apoptosis.
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Affiliation(s)
- M Won
- Department of Pharmacology, Research Institute for Medical Science, Infection Signaling Network Research Center, Daejeon Regional Cancer Center, College of Medicine, Chungnam National University, Daejeon, Korea
| | - KA Park
- Department of Pharmacology, Research Institute for Medical Science, Infection Signaling Network Research Center, Daejeon Regional Cancer Center, College of Medicine, Chungnam National University, Daejeon, Korea
| | - HS Byun
- Department of Pharmacology, Research Institute for Medical Science, Infection Signaling Network Research Center, Daejeon Regional Cancer Center, College of Medicine, Chungnam National University, Daejeon, Korea
| | - K-C Sohn
- Department of Dermatology, College of Medicine, Chungnam National University, Daejeon, Korea
| | - Y-R Kim
- Department of Pharmacology, Research Institute for Medical Science, Infection Signaling Network Research Center, Daejeon Regional Cancer Center, College of Medicine, Chungnam National University, Daejeon, Korea
| | - J Jeon
- Department of Pharmacology, Research Institute for Medical Science, Infection Signaling Network Research Center, Daejeon Regional Cancer Center, College of Medicine, Chungnam National University, Daejeon, Korea
| | - JH Hong
- Department of Pharmacology, Research Institute for Medical Science, Infection Signaling Network Research Center, Daejeon Regional Cancer Center, College of Medicine, Chungnam National University, Daejeon, Korea
| | - J Park
- Department of Pharmacology, Research Institute for Medical Science, Infection Signaling Network Research Center, Daejeon Regional Cancer Center, College of Medicine, Chungnam National University, Daejeon, Korea
| | - JH Seok
- Department of Pharmacology, Research Institute for Medical Science, Infection Signaling Network Research Center, Daejeon Regional Cancer Center, College of Medicine, Chungnam National University, Daejeon, Korea
| | - JM Kim
- Department of Pathology, College of Medicine, Chungnam National University, Daejeon, Korea
| | - W-H Yoon
- Department of Biochemistry, College of Medicine, Chungnam National University, Daejeon, Korea
| | - I-S Jang
- Department of Surgery, College of Medicine, Chungnam National University, Daejeon, Korea
| | - HM Shen
- Department of Epidemiology and Public Health, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - ZG Liu
- Cell and Cellular Biology Branch, Center for Cancer Research, National Cancer Institute, National Institute of Health, Bethesda, MD, USA
| | - GM Hur
- Department of Pharmacology, Research Institute for Medical Science, Infection Signaling Network Research Center, Daejeon Regional Cancer Center, College of Medicine, Chungnam National University, Daejeon, Korea
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143
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Gram-positive pathogenic bacteria induce a common early response in human monocytes. BMC Microbiol 2010; 10:275. [PMID: 21044323 PMCID: PMC2988769 DOI: 10.1186/1471-2180-10-275] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2010] [Accepted: 11/02/2010] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND We infected freshly isolated human peripheral monocytes with live bacteria of three clinically important gram-positive bacterial species, Staphylococcus aureus, Streptococcus pneumoniae and Listeria monocytogenes and studied the ensuing early transcriptional response using expression microarrays. Thus the observed response was unbiased by signals originating from other helper and effector cells of the host and was not limited to induction by solitary bacterial constituents. RESULTS Activation of monocytes was demonstrated by the upregulation of chemokine rather than interleukin genes except for the prominent expression of interleukin 23, marking it as the early lead cytokine. This activation was accompanied by cytoskeleton rearrangement signals and a general anti-oxidative stress and anti-apoptotic reaction. Remarkably, the expression profiles also provide evidence that monocytes participate in the regulation of angiogenesis and endothelial function in response to these pathogens. CONCLUSION Regardless of the invasion properties and survival mechanisms of the pathogens used, we found that the early response comprised of a consistent and common response. The common response was hallmarked by the upregulation of interleukin 23, a rather unexpected finding regarding Listeria infection, as this cytokine has been linked primarily to the control of extracellular bacterial dissemination.
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144
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Zinc-suppressed inflammatory cytokines by induction of A20-mediated inhibition of nuclear factor-κB. Nutrition 2010; 27:816-23. [PMID: 21035309 DOI: 10.1016/j.nut.2010.08.010] [Citation(s) in RCA: 120] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2010] [Revised: 08/05/2010] [Accepted: 08/12/2010] [Indexed: 12/14/2022]
Abstract
OBJECTIVE Chronic generation of inflammatory cytokines and reactive oxygen species are implicated in atherosclerosis, aging, cancers, and other chronic diseases. We hypothesized that zinc induces A20 in premonocytic, endothelial, and cancer cells, and A20 binds to tumor necrosis factor (TNF)-receptor associated factor, and inhibits Iκ kinase-α (IKK-α)/nuclear factor-κB (NF-κB), resulting in downregulation of TNF-α and interleukin-1β (IL-1β). METHODS To test this hypothesis, we used HL-60, human umbilical vein endothelial cells, and SW480 cell lines under zinc-deficient and zinc-sufficient conditions in this study. We measured oxidative stress markers, inflammatory cytokines, A20 protein and mRNA, A20-FRAF-1 complex, and IKK-α/NF-κB signaling in stimulated zinc-deficient and zinc sufficient cells. We also conducted antisense A20 and siRNA studies to investigate the regulatory role of zinc in TNF-α and IL-1β via A20. RESULTS We found that zinc increased A20 and A20-tumor necrosis factor-receptor associated factor-1 complex, decreased the IKK-α/NF-κB signaling pathway, oxidative stress markers, and inflammatory cytokines in these cells compared with zinc-deficient cells. We confirmed that zinc-induced A20 contributes to downregulation of TNF-α and IL-1β by antisense and short interfering RNA A20 studies. CONCLUSION Our studies suggest that zinc suppresses generation of NF-κB-regulated inflammatory cytokines by induction of A20.
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145
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Shi D, Grossman SR. Ubiquitin becomes ubiquitous in cancer: emerging roles of ubiquitin ligases and deubiquitinases in tumorigenesis and as therapeutic targets. Cancer Biol Ther 2010; 10:737-47. [PMID: 20930542 DOI: 10.4161/cbt.10.8.13417] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
By virtue of its ability to regulate both protein turnover and non-proteolytic signalling functions, ubiquitin protein conjugation has been implicated in the control of multiple cellular processes, including protein localization, cell cycle control, transcription regulation, DNA damage repair, and endocytosis. Ubiquitin metabolism enzymes have been identified as either oncogenes or tumor suppressors in a variety of cancers. Given that ubiquitin metabolism is governed by enzymes--E1, E2, E3, E4, deubiquitinases (DUBs), and the proteasome- the system as a whole is ripe for target and drug discovery in cancer. Of the ubiquitin/proteasome system components, the E3's and DUBs can recognize substrates with the most specificity, and are thus of key interest as drug targets in cancer. This review examines the molecular role in cancer, relevant substrates, and potential for pharmacologic development, of E3's and DUBs that have been associated thus far with human malignancies as oncogenes or tumor suppressors.
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Affiliation(s)
- Dingding Shi
- Departments of Cancer Biology, University of Massachusetts Medical School and UMass Memorial Cancer Center, Worcester, MA, USA
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146
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Hah YS, Lee YR, Jun JS, Lim HS, Kim HO, Jeong YG, Hur GM, Lee SY, Chung MJ, Park JW, Lee SI, Park BH. A20 suppresses inflammatory responses and bone destruction in human fibroblast-like synoviocytes and in mice with collagen-induced arthritis. ACTA ACUST UNITED AC 2010; 62:2313-21. [PMID: 20506221 DOI: 10.1002/art.27545] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE Nuclear factor-kappaB (NF-kappaB) has been implicated as a therapeutic target for the treatment of rheumatoid arthritis (RA). The purpose of this study was to determine whether A20, a universal inhibitor of NF-kappaB, might have antiarthritic effects. METHODS An adenovirus containing A20 complementary DNA (AdA20) was used to deliver A20 to human rheumatoid fibroblast-like synoviocytes (FLS) in vitro as well as to mice with collagen-induced arthritis (CIA) in vivo via intraarticular injection into the ankle joints bilaterally. RESULTS In vitro experiments demonstrated that AdA20 suppressed NF-kappaB activation, chemokine production, and matrix metalloproteinase secretion induced by tumor necrosis factor alpha in FLS. Mice with CIA that were treated with AdA20 had a lower cumulative disease incidence and severity of arthritis, based on hind paw thickness, radiologic and histopathologic findings, and inflammatory cytokine levels, than did control virus-injected mice. The protective effects of AdA20 were mediated by the inhibition of the NF-kappaB signaling pathway. The severity of arthritis was also significantly decreased in the untreated front paws, indicating a beneficial systemic effect of local suppression of NF-kappaB. Surprisingly, mice treated with AdA20 after the onset of CIA had significantly decreased arthritis severity from the onset of clinical signs to the end of the study. CONCLUSION These results suggest that using A20 to block the NF-kappaB pathway in rheumatoid joints reduces both the inflammatory response and the tissue destruction. The development of an immunoregulatory strategy based on A20 may therefore have therapeutic potential in the treatment of RA.
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Affiliation(s)
- Young-Sool Hah
- Gyeongsang National University Hospital and Gyeongsang National University School of Medicine, Jinju, Gyeongnam, Republic of Korea
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147
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Frenzel LP, Claus R, Plume N, Schwamb J, Konermann C, Pallasch CP, Claasen J, Brinker R, Wollnik B, Plass C, Wendtner CM. Sustained NF-kappaB activity in chronic lymphocytic leukemia is independent of genetic and epigenetic alterations in the TNFAIP3 (A20) locus. Int J Cancer 2010; 128:2495-500. [DOI: 10.1002/ijc.25579] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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148
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Dishevelled interacts with p65 and acts as a repressor of NF-κB-mediated transcription. Cell Res 2010; 20:1117-27. [DOI: 10.1038/cr.2010.108] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
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149
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Verstrepen L, Verhelst K, van Loo G, Carpentier I, Ley SC, Beyaert R. Expression, biological activities and mechanisms of action of A20 (TNFAIP3). Biochem Pharmacol 2010; 80:2009-20. [PMID: 20599425 DOI: 10.1016/j.bcp.2010.06.044] [Citation(s) in RCA: 172] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2010] [Revised: 06/22/2010] [Accepted: 06/25/2010] [Indexed: 12/17/2022]
Abstract
A20 (also known as TNFAIP3) is a cytoplasmic protein that plays a key role in the negative regulation of inflammation and immunity. Polymorphisms in the A20 gene locus have been identified as risk alleles for multiple human autoimmune diseases, and A20 has also been proposed to function as a tumor suppressor in several human B-cell lymphomas. A20 expression is strongly induced by multiple stimuli, including the proinflammatory cytokines TNF and IL-1, and microbial products that trigger pathogen recognition receptors, such as Toll-like receptors. A20 functions in a negative feedback loop, which mediates its inhibitory functions by downregulating key proinflammatory signaling pathways, including those controlling NF-κB- and IRF3-dependent gene expression. Activation of these transcription factors is controlled by both K48- and K63- polyubiquitination of upstream signaling proteins, respectively triggering proteasome-mediated degradation or interaction with other signaling proteins. A20 turns off NF-κB and IRF3 activation by modulating both types of ubiquitination. Induction of K48-polyubiquitination by A20 involves its C-terminal zinc-finger ubiquitin-binding domain, which may promote interaction with E3 ligases, such as Itch and RNF11 that are involved in mediating A20 inhibitory functions. A20 is thought to promote de-ubiquitination of K63-polyubiquitin chains either directly, due to its N-terminal deubiquitinase domain, or by disrupting the interaction between E3 and E2 enzymes that catalyze K63-polyubiquitination. A20 is subject to different mechanisms of regulation, including phosphorylation, proteolytic processing, and association with ubiquitin binding proteins. Here we review the expression and biological activities of A20, as well as the underlying molecular mechanisms.
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Affiliation(s)
- Lynn Verstrepen
- Unit of Molecular Signal Transduction in Inflammation, Department for Molecular Biomedical Research, VIB, Technologiepark 927, 9000 Ghent, Belgium
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150
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Yang L, Gu L, Li Z, Zhou M. Translation of TRAF1 is regulated by IRES-dependent mechanism and stimulated by vincristine. Nucleic Acids Res 2010; 38:4503-13. [PMID: 20413583 PMCID: PMC2910060 DOI: 10.1093/nar/gkq183] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2010] [Revised: 03/03/2010] [Accepted: 03/04/2010] [Indexed: 11/20/2022] Open
Abstract
TRAF1 is a member of the TRAF family, which plays important roles in signal transduction that mediate cell life and death in the immune response, inflammatory and malignant diseases. It is known that TRAF1 transcription is inducible by various cytokines, but little is known about the regulation of its mRNA translation. In the present study, we demonstrated that the human TRAF1 mRNA has an unusually long 5'-UTR that contains internal ribosome entry segment (IRES) regulating its translation. By performing gene transfection and reporter assays, we revealed that this IRES sequence is located within the 572 nt upstream from the AUG start codon. An element between nt -392 and -322 was essential for the IRES activity. Interestingly, we found that the TRAF1 expression is induced in cancer cells by chemotherapeutic drug vincristine that regulates cytoplasmic localization of polypyrimidine tract binding protein, which may contribute to the IRES-dependent translation of TRAF1 during vincristine treatment. These results indicate that TRAF1 translation is initiated via the IRES and regulated by vincristine, and suggest that regulation of the IRES-dependent translation of TRAF1 may be involved in effecting the cancer cell response to vincristine treatment.
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Affiliation(s)
- Lin Yang
- Departments of Pediatrics, Aflac Cancer Center and Blood Disorders Service, Emory University School of Medicine, Atlanta, GA 30322, USA and Department of Immunology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Lubing Gu
- Departments of Pediatrics, Aflac Cancer Center and Blood Disorders Service, Emory University School of Medicine, Atlanta, GA 30322, USA and Department of Immunology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Zhuoya Li
- Departments of Pediatrics, Aflac Cancer Center and Blood Disorders Service, Emory University School of Medicine, Atlanta, GA 30322, USA and Department of Immunology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Muxiang Zhou
- Departments of Pediatrics, Aflac Cancer Center and Blood Disorders Service, Emory University School of Medicine, Atlanta, GA 30322, USA and Department of Immunology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
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