scholarly journals A Novel Inhibitor of the NF-κB Signaling Pathway Encoded by the Parapoxvirus Orf Virus

2010 ◽  
Vol 84 (8) ◽  
pp. 3962-3973 ◽  
Author(s):  
D. G. Diel ◽  
G. Delhon ◽  
S. Luo ◽  
E. F. Flores ◽  
D. L. Rock
Keyword(s):  
Immune Responses ◽  
Signaling Pathway ◽  
Viral Infections ◽  
Nuclear Translocation ◽  
Orf Virus ◽  
Necrosis Factor Alpha ◽  
Iκb Kinase ◽  
Genes Expression ◽  
Tnf Α ◽  
Factor Alpha

ABSTRACT The parapoxvirus orf virus (ORFV) is a pathogen of sheep and goats that has been used as a preventive and therapeutic immunomodulatory agent in several animal species. However, the functions (genes, proteins, and mechanisms of action) evolved by ORFV to modulate and manipulate immune responses are poorly understood. Here, the novel ORFV protein ORFV024 was shown to inhibit activation of the NF-κB signaling pathway, an important modulator of early immune responses against viral infections. Infection of primary ovine cells with an ORFV024 deletion mutant virus resulted in a marked increase in expression of NF-κB-regulated chemokines and other proinflammatory host genes. Expression of ORFV024 in cell cultures significantly decreased lipopolysaccharide (LPS)- and tumor necrosis factor alpha (TNF-α)-induced NF-κB-responsive reporter gene expression. Further, ORFV024 expression decreased TNF-α-induced phosphorylation and nuclear translocation of NF-κB-p65, phosphorylation, and degradation of IκBα, and phosphorylation of IκB kinase (IKK) subunits IKKα and IKKβ, indicating that ORFV024 functions by inhibiting activation of IKKs, the bottleneck for most NF-κB activating stimuli. Although ORFV024 interferes with activation of the NF-κB signaling pathway, its deletion from the OV-IA82 genome had no significant effect on disease severity, progression, and time to resolution in sheep, indicating that ORFV024 is not essential for virus virulence in the natural host. This represents the first description of a NF-κB inhibitor encoded by a parapoxvirus.

scholarly journals Herpes Simplex Virus 1 E3 Ubiquitin Ligase ICP0 Protein Inhibits Tumor Necrosis Factor Alpha-Induced NF-κB Activation by Interacting with p65/RelA and p50/NF-κB1

2013 ◽  
Vol 87 (23) ◽  
pp. 12935-12948 ◽  
Author(s):  
Jie Zhang ◽  
Kezhen Wang ◽  
Shuai Wang ◽  
Chunfu Zheng
Keyword(s):  
Tumor Necrosis Factor ◽  
Ubiquitin Ligase ◽  
Tumor Necrosis ◽  
Nuclear Translocation ◽  
E3 Ubiquitin Ligase ◽  
Necrosis Factor Alpha ◽  
Tnf Α ◽  
Factor Alpha ◽  
Necrosis Factor ◽  
Hsv 1

NF-κB plays central roles in regulation of diverse biological processes, including innate and adaptive immunity and inflammation. HSV-1 is the archetypal member of the alphaherpesviruses, with a large genome encoding over 80 viral proteins, many of which are involved in virus-host interactions and show immune modulatory capabilities. In this study, we demonstrated that the HSV-1 ICP0 protein, a viral E3 ubiquitin ligase, was shown to significantly suppress tumor necrosis factor alpha (TNF-α)-mediated NF-κB activation. ICP0 was demonstrated to bind to the NF-κB subunits p65 and p50 by coimmunoprecipitation analysis. ICP0 bound to the Rel homology domain (RHD) of p65. Fluorescence microscopy demonstrated that ICP0 abolished nuclear translocation of p65 upon TNF-α stimulation. Also, ICP0 degraded p50 via its E3 ubiquitin ligase activity. The RING finger (RF) domain mutant ICP0 (ICP0-RF) lost its ability to inhibit TNF-α-mediated NF-κB activation and p65 nuclear translocation and degrade p50. Notably, the RF domain of ICP0 was sufficient to interact with p50 and abolish NF-κB reporter gene activity. Here, it is for the first time shown that HSV-1 ICP0 interacts with p65 and p50, degrades p50 through the ubiquitin-proteasome pathway, and prevents NF-κB-dependent gene expression, which may contribute to immune evasion and pathogenesis of HSV-1.

scholarly journals NF-κB Activation by Double-Stranded-RNA-Activated Protein Kinase (PKR) Is Mediated through NF-κB-Inducing Kinase and IκB Kinase

2000 ◽  
Vol 20 (4) ◽  
pp. 1278-1290 ◽  
Author(s):  
Maryam Zamanian-Daryoush ◽  
Trine H. Mogensen ◽  
Joseph A. DiDonato ◽  
Bryan R. G. Williams
Keyword(s):  
Protein Kinase ◽  
Kinetic Studies ◽  
Dominant Negative ◽  
Dominant Negative Mutant ◽  
Null Cell ◽  
Necrosis Factor Alpha ◽  
Double Stranded Rna ◽  
Iκb Kinase ◽  
Tnf Α ◽  
Factor Alpha

ABSTRACT The interferon (IFN)-inducible double-stranded-RNA (dsRNA)-activated serine-threonine protein kinase (PKR) is a major mediator of the antiviral and antiproliferative activities of IFNs. PKR has been implicated in different stress-induced signaling pathways including dsRNA signaling to nuclear factor kappa B (NF-κB). The mechanism by which PKR mediates activation of NF-κB is unknown. Here we show that in response to poly(rI) · poly(rC) (pIC), PKR activates IκB kinase (IKK), leading to the degradation of the inhibitors IκBα and IκBβ and the concomitant release of NF-κB. The results of kinetic studies revealed that pIC induced a slow and prolonged activation of IKK, which was preceded by PKR activation. In PKR null cell lines, pIC failed to stimulate IKK activity compared to cells from an isogenic background wild type for PKR in accord with the inability of PKR null cells to induce NF-κB in response to pIC. Moreover, PKR was required to establish a sustained response to tumor necrosis factor alpha (TNF-α) and to potentiate activation of NF-κB by cotreatment with TNF-α and IFN-γ. By coimmunoprecipitation, PKR was shown to be physically associated with the IKK complex. Transient expression of a dominant negative mutant of IKKβ or the NF-κB-inducing kinase (NIK) inhibited pIC-induced gene expression from an NF-κB-dependent reporter construct. Taken together, these results demonstrate that PKR-dependent dsRNA induction of NF-κB is mediated by NIK and IKK activation.

TNF-α and IL-6: The Link between Immune and Bone System

2020 ◽  
Vol 21 (3) ◽  
pp. 213-227 ◽  
Author(s):  
Tiantian Wang ◽  
Chengqi He
Keyword(s):  
Immune Responses ◽  
Macrophage Activation ◽  
Bone Diseases ◽  
Necrosis Factor Alpha ◽  
Immune Mediated ◽  
Pathogenic Factors ◽  
Tnf Α ◽  
Proliferation And Differentiation ◽  
Factor Alpha ◽  
Necrosis Factor

Osteoimmunology is a new subject which focuses on the communication between the immune and the skeletal systems. Both the immune system and bone communicate with each other. Proinflammatory cytokines, such as tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) play important roles in immune responses and bone metabolism. TNF-α and IL-6 enhance macrophage activation and antigen presentation, as well as regulating immunity through different mechanisms. A variety of groups have reported that TNF-α suppresses osteoblasts activity at some stages of differentiation and stimulates osteoclast proliferation and differentiation. In contrast, IL-6 mediates the actions of osteoblasts and osteoclasts through sophisticated mechanisms, which reflect dual effects. Both TNF-α and IL-6 can mediate the activity of osteocytes. Furthermore, both TNF-α and IL-6 are important pathogenic factors related to immune-mediated bone diseases including rheumatoid arthritis and postmenopausal osteoporosis. This review will discuss the contradictory findings concerning TNF-α and IL-6 in osteoimmunology and their potential for clinical application.

scholarly journals Virus-Cell Interactions Regulating Induction of Tumor Necrosis Factor Alpha Production in Macrophages Infected with Herpes Simplex Virus

2001 ◽  
Vol 75 (21) ◽  
pp. 10170-10178 ◽  
Author(s):  
Søren R. Paludan ◽  
Søren C. Mogensen
Keyword(s):  
Tumor Necrosis ◽  
Nuclear Translocation ◽  
Viral Dna ◽  
Necrosis Factor Alpha ◽  
Tnf Α ◽  
Factor Alpha ◽  
Ifn Γ ◽  
Simplex Virus ◽  
Necrosis Factor ◽  
Hsv 1

ABSTRACT Macrophages respond to virus infections by rapidly secreting proinflammatory cytokines, which play an important role in the first line of defense. Tumor necrosis factor alpha (TNF-α) is one of the major macrophage-produced cytokines. In this study we have investigated the virus-cell interactions responsible for induction of TNF-α expression in herpes simplex virus (HSV)-infected macrophages. Both HSV type 1 (HSV-1) and HSV-2 induced TNF-α expression in macrophages activated with gamma interferon (IFN-γ). This induction was to some extent sensitive to UV treatment of the virus. Virus particles unable to enter the cells displayed reduced capacity to stimulate TNF-α expression but retained a significant portion which was abolished by HSV-specific antibodies. Recombinant HSV-1 glycoprotein D was able to trigger TNF-α secretion in concert with IFN-γ. Sugar moieties of HSV glycoproteins have been reported to be involved in induction of IFN-α but did not contribute to TNF-α expression in macrophages. Moreover, the entry-dependent portion of the TNF-α induction was investigated with HSV-1 mutants and found to be independent of the tegument proteins VP16 and UL13 and partly dependent on nuclear translocation of the viral DNA. Finally, we found that macrophages expressing an inactive mutant of the double-stranded RNA (dsRNA)-activated protein kinase (PKR) produced less TNF-α in response to infectious HSV infection than the empty-vector control cell line but displayed the same responsiveness to UV-inactivated virus. These results indicate that HSV induces TNF-α expression in macrophages through mechanisms involving (i) viral glycoproteins, (ii) early postentry events occurring prior to nuclear translocation of viral DNA, and (iii) viral dsRNA-PKR.

scholarly journals βTrCP-Mediated Proteolysis of NF-κB1 p105 Requires Phosphorylation of p105 Serines 927 and 932

2003 ◽  
Vol 23 (1) ◽  
pp. 402-413 ◽  
Author(s):  
Valerie Lang ◽  
Julia Janzen ◽  
Gregory Zvi Fischer ◽  
Yasmina Soneji ◽  
Sören Beinke ◽  
...  
Keyword(s):  
Target Sequence ◽  
Double Knockout ◽  
Necrosis Factor Alpha ◽  
Ubiquitin E3 Ligase ◽  
Iκb Kinase ◽  
Tnf Α ◽  
Ikk Complex ◽  
Factor Alpha ◽  
Necrosis Factor

ABSTRACT NF-κB1 p105 functions both as a precursor of NF-κB1 p50 and as a cytoplasmic inhibitor of NF-κB. Following the stimulation of cells with tumor necrosis factor alpha (TNF-α), the IκB kinase (IKK) complex rapidly phosphorylates NF-κB1 p105 on serine 927 in the PEST region. This phosphorylation is essential for TNF-α to trigger p105 degradation, which releases the associated Rel/NF-κB subunits to translocate into the nucleus and regulate target gene transcription. Serine 927 resides in a conserved motif (Asp-Ser927-Gly-Val-Glu-Thr-Ser932) homologous to the IKK target sequence in IκBα. In this study, TNF-α-induced p105 proteolysis was revealed to additionally require the phosphorylation of serine 932. Experiments with IKK1−/− and IKK2−/− double knockout embryonic fibroblasts demonstrate that the IKK complex is essential for TNF-α to stimulate phosphorylation on p105 serines 927 and 932. Furthermore, purified IKK1 and IKK2 can each phosphorylate a glutathione S-transferase-p105758-967 fusion protein on both regulatory serines in vitro. IKK-mediated p105 phosphorylation generates a binding site for βTrCP, the receptor subunit of an SCF-type ubiquitin E3 ligase, and depletion of βTrCP by RNA interference blocks TNF-α-induced p105 ubiquitination and proteolysis. Phosphopeptide competition experiments indicate that βTrCP binds p105 more effectively when both serines 927 and 932 are phosphorylated. Interestingly, however, βTrCP affinity for the IKK-phosphorylated sequence on p105 is substantially lower than that on IκBα. Thus, it appears that reduced p105 recruitment of βTrCP and subsequent ubiquitination may contribute to delayed p105 proteolysis after TNF-α stimulation relative to that for IκBα.

scholarly journals Transforming Growth Factor β Enhances Respiratory Syncytial Virus Replication and Tumor Necrosis Factor Alpha Induction in Human Epithelial Cells

2007 ◽  
Vol 81 (6) ◽  
pp. 2880-2886 ◽  
Author(s):  
Kelly L. McCann ◽  
Farhad Imani
Keyword(s):  
Tumor Necrosis ◽  
Transforming Growth Factor ◽  
Viral Infections ◽  
Transforming Growth Factor Β ◽  
Necrosis Factor Alpha ◽  
Tnf Α ◽  
Factor Alpha ◽  
Respiratory Viral Infections ◽  
Syncytial Virus ◽  
Necrosis Factor

ABSTRACT Asthma is characterized as a chronic inflammatory disease associated with significant tissue remodeling. Patients with asthma are more susceptible to virus-induced exacerbation, which subsequently can lead to increased rates of hospitalization and mortality. While the most common cause of asthma-related deaths is respiratory viral infections, the underlying factors in the lung environment which render asthmatic subjects more susceptible to viral exacerbation are not yet identified. Since transforming growth factor β (TGF-β) is a critical cytokine for lung tissue remodeling and asthma phenotype, we have focused on the effects of TGF-β on viral replication and virus-induced inflammation. Treatment of human epithelial cells with TGF-β increased respiratory syncytial virus (RSV) replication by approximately fourfold. Tumor necrosis factor alpha (TNF-α) mRNA and protein expression were also significantly increased above levels with RSV infection alone. The increase in RSV replication and TNF-α expression after TGF-β treatment was concomitant with an increase in virus-induced p38 mitogen-activated protein kinase activation. Our data reveal a novel effect for TGF-β on RSV replication and provide a potential mechanism for the exaggerated inflammatory response observed in asthmatic subjects during respiratory viral infections.

scholarly journals Rhinovirus Replication in Human Macrophages Induces NF-κB-Dependent Tumor Necrosis Factor Alpha Production

2006 ◽  
Vol 80 (16) ◽  
pp. 8248-8258 ◽  
Author(s):  
Vasile Laza-Stanca ◽  
Luminita A. Stanciu ◽  
Simon D. Message ◽  
Michael R. Edwards ◽  
James E. Gern ◽  
...  
Keyword(s):  
Tumor Necrosis Factor ◽  
Virus Replication ◽  
Tumor Necrosis ◽  
Nuclear Translocation ◽  
Necrosis Factor Alpha ◽  
Human Macrophages ◽  
Tnf Α ◽  
Acute Exacerbations ◽  
Factor Alpha ◽  
Necrosis Factor

ABSTRACT Rhinoviruses (RV) are the major cause of acute exacerbations of asthma and chronic obstructive pulmonary disease (COPD). Rhinoviruses have been shown to activate macrophages, but rhinovirus replication in macrophages has not been reported. Tumor necrosis factor alpha (TNF-α) is implicated in the pathogenesis of acute exacerbations, but its cellular source and mechanisms of induction by virus infection are unclear. We hypothesized that rhinovirus replication in human macrophages causes activation and nuclear translocation of NF-κB, leading to TNF-α production. Using macrophages derived from the human monocytic cell line THP-1 and from primary human monocytes, we demonstrated that rhinovirus replication was productive in THP-1 macrophages, leading to release of infectious virus into supernatants, but was limited in monocyte-derived macrophages, likely due to type I interferon production, which was robust in monocyte-derived but deficient in THP-1-derived macrophages. Similar to bronchial epithelial cells, only small numbers of cells supported complete virus replication. We demonstrated RV-induced activation of NF-κB and colocalization of p65/NF-κB nuclear translocation with virus replication in both macrophage types. The infection induced TNF-α release in a time- and dose-dependent, RV serotype- and receptor-independent manner and was largely (THP-1 derived) or completely (monocyte derived) dependent upon virus replication. Finally, we established the requirement for NF-κB but not p38 mitogen-activated protein kinase in induction of TNF-α. These data suggest RV infection of macrophages may be an important source of proinflammatory cytokines implicated in the pathogenesis of exacerbations of asthma and COPD. They also confirm inhibition of NF-κB as a promising target for development of new therapeutic intervention strategies.

scholarly journals New Mechanism by Which Human Cytomegalovirus MicroRNAs Negate the Proinflammatory Response to Infection

mBio ◽  
2017 ◽  
Vol 8 (2) ◽  
Author(s):  
Andrew D. Yurochko
Keyword(s):  
Human Cytomegalovirus ◽  
Nuclear Translocation ◽  
Proinflammatory Response ◽  
Necrosis Factor Alpha ◽  
Host Cell Response ◽  
Tnf Α ◽  
Infected Cells ◽  
Factor Alpha ◽  
Direct Targeting ◽  
External Stimuli

ABSTRACT Viruses have evolved many novel mechanisms to promote infection and to mitigate the host cell response to that infection. In the article by M. H. Hancock et al. (mBio 8:e00109-17, 2017, https://doi.org/10.1128/mBio.00109-17 !), the authors describe a new mechanism by which human cytomegalovirus (HCMV) microRNAs (miRNAs; miR-US5-1 and miR-UL112-3p) negate the proinflammatory response to infection. The authors document that these two viral miRNAs downregulate the NF-κB response through direct targeting of the IKKα and IKKβ mRNAs, which in turn, through diminished IκB kinases (IKKs), block production of proinflammatory cytokines (interleukin-6 [IL-6], CCL5, and tumor necrosis factor alpha [TNF-α]). Because most signaling pathways that promote NF-κB activation and nuclear translocation ultimately converge on the activation of the IKK complex, this new study documents that HCMV can strongly dictate how infected cells respond to internal and/or external stimuli and thus positively influence the outcome of both lytic and latent infection.

scholarly journals Prohibitin Inhibits Tumor Necrosis Factor alpha–induced Nuclear Factor-kappa B Nuclear Translocation via the Novel Mechanism of Decreasing Importin α3 Expression

2009 ◽  
Vol 20 (20) ◽  
pp. 4412-4423 ◽  
Author(s):  
Arianne L. Theiss ◽  
Aaron K. Jenkins ◽  
Ngozi I. Okoro ◽  
Jan-Michael A. Klapproth ◽  
Didier Merlin ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Intestinal Inflammation ◽  
Nuclear Translocation ◽  
Intestinal Epithelial Cells ◽  
Intestinal Epithelial ◽  
Necrosis Factor Alpha ◽  
Tnf Α ◽  
Factor Alpha

Expression of prohibitin 1 (PHB), a multifunctional protein in the cell, is decreased during inflammatory bowel disease (IBD). Little is known regarding the regulation and role of PHB during intestinal inflammation. We examined the effect of tumor necrosis factor alpha (TNF-α), a cytokine that plays a central role in the pathogenesis of IBD, on PHB expression and the effect of sustained PHB expression on TNF-α activation of nuclear factor-kappa B (NF-κB) and epithelial barrier dysfunction, two hallmarks of intestinal inflammation. We show that TNF-α decreased PHB protein and mRNA abundance in intestinal epithelial cells in vitro and in colon mucosa in vivo. Sustained expression of prohibitin in intestinal epithelial cells in vitro and in vivo (prohibitin transgenic mice, PHB TG) resulted in a marked decrease in TNF-α–induced nuclear translocation of the NF-κB protein p65, NF-κB/DNA binding, and NF-κB–mediated transcriptional activation despite robust IκB-α phosphorylation and degradation and increased cytosolic p65. Cells overexpressing PHB were protected from TNF-α–induced increased epithelial permeability. Expression of importin α3, a protein involved in p50/p65 nuclear import, was decreased in cells overexpressing PHB and in colon mucosa of PHB TG mice. Restoration of importin α3 levels sustained NF-κB activation by TNF-α during PHB transfection. These results suggest that PHB inhibits NF-κB nuclear translocation via a novel mechanism involving alteration of importin α3 levels. TNF-α decreases PHB expression in intestinal epithelial cells and restoration of PHB expression in these cells can protect against the deleterious effects of TNF-α and NF-κB on barrier function.

scholarly journals Identification of Tumor Necrosis Factor-Alpha (TNF-α) Inhibitor in Rheumatoid Arthritis Using Network Pharmacology and Molecular Docking

2021 ◽  
Vol 12 ◽  
Author(s):  
Liang Liang Bai ◽  
Hao Chen ◽  
Peng Zhou ◽  
Jun Yu
Keyword(s):  
Molecular Docking ◽  
Signaling Pathway ◽  
Target Genes ◽  
Network Pharmacology ◽  
Active Ingredients ◽  
Necrosis Factor Alpha ◽  
Tnf Α ◽  
Receptor Signaling Pathway ◽  
Factor Alpha ◽  
Necrosis Factor

Background: This study aimed to investigate the molecular mechanism of Radix Paeoniae Alba (white peony, WP) in treating immune inflammatory diseases of rheumatoid arthritis (RA) and tumor necrosis factor-alpha (TNF-α) inhibitors (TNFis) by using network pharmacology and molecular docking.Methods: In this study, the ingredient of WP and the potential inflammatory targets of RA were obtained from the Traditional Chinese Medicine Systematic Pharmacology Database, GeneCard, and OMIM databases, respectively. The establishment of the RA–WP-potential inflammatory target gene interaction network was accomplished using the STRING database. Network maps of the WP–RA-potential inflammatory target gene network were constructed using Cytoscape software. Gene ontology (GO) and the biological pathway (KEGG) enrichment analyses were used to further explore the RA mechanism and therapeutic effects of WP. Molecular docking technology was used to analyze the optimal effective components from WP for docking with TNF-α.Results: Thirteen active ingredients and 71 target genes were screened from WP, and 49 of the target genes intersected with RA target inflammatory genes and were considered potential therapeutic targets. Network pharmacological analysis showed that the WP active ingredients such as mairin, DPHCD, (+)-catechin, beta-sitosterol, paeoniflorin, sitosterol, and kaempferol showed better correlation with RA inflammatory target genes such as PGR, PTGS1, PTGS2, NR3C2, TNFSF15, and CHRM2, respectively. The immune-inflammatory signaling pathways of the active ingredients for the treatment of RA are the TNF-α signaling pathway, Toll-like receptor signaling pathway, cell apoptosis, interleukin-17 signaling pathway, C-type lectin receptor signaling pathway, mitogen-associated protein kinase, etc. Molecular docking results suggested that mairin was the most appropriate natural TNFis.Conclusion: Our findings provide an essential role and basis for further immune-inflammatory studies into the molecular mechanisms of WP and TNFis development in RA.

Sign in / Sign up

Export Citation Format

Share Document