scholarly journals Filamin A Expression Negatively Regulates Sphingosine-1-Phosphate-Induced NF-κB Activation in Melanoma Cells by Inhibition of Akt Signaling

2015 ◽  
pp. MCB.00554-15 ◽  
Author(s):  
Ludmila Campos ◽  
Yamila Rodriguez ◽  
Andreia Machado Leopoldino ◽  
Nitai C. Hait ◽  
Pablo Lopez Bergami ◽  
...  
Keyword(s):  
Nuclear Translocation ◽  
Melanoma Cells ◽  
Lipid Mediator ◽  
Filamin A ◽  
Necrosis Factor Alpha ◽  
Akt Activation ◽  
Sphingosine 1 Phosphate ◽  
Negative Role ◽  
Factor Alpha ◽  
G Protein Coupled

Sphingosine-1-phosphate (S1P) is a bioactive lipid mediator that regulates many processes in inflammation and cancer. S1P is a ligand for five G protein-coupled receptors, S1PR1-5, and also has important intracellular actions. Previously we have shown that intracellular S1P is involved in tumor necrosis factor alpha (TNF)-induced NF-κB activation in melanoma cell lines that express filamin A (FLNA). Here, we show that extracellular S1P activates NF-κB only in melanoma cells that lack FLNA. In these cells S1P, but not TNF, promotes IKK and p65 phosphorylation, IκBα degradation, p65 nuclear translocation and NF-κB reporter activity. NF-κB activation induced by S1P was mediated via S1PR1 and S1PR2. Exogenous S1P enhanced phosphorylation of PKCδ and its downregulation reduced S1P-induced phosphorylation of IKK and p65. In addition, silencing of Bcl10 also inhibited S1P-induced IKK phosphorylation. Surprisingly, S1P reduced Akt activation in melanoma cells that express FLNA, whereas in the absence of FLNA, high phosphorylation levels of Akt were maintained, enabling S1P-mediated NF-κB signaling. In accord, inhibition of Akt suppressed S1P-mediated IKK and p65 phosphorylation and degradation of IκBα. Hence, these results support a negative role of FLNA in S1P-mediated NF-κB activation in melanoma cells through modulation of Akt.

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 The Inflammatory Response Induced by Aspartic Proteases of Candida albicans Is Independent of Proteolytic Activity

2010 ◽  
Vol 78 (11) ◽  
pp. 4754-4762 ◽  
Author(s):  
Donatella Pietrella ◽  
Anna Rachini ◽  
Neelam Pandey ◽  
Lydia Schild ◽  
Mihai Netea ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Inflammatory Response ◽  
Proteolytic Activity ◽  
Necrosis Factor Alpha ◽  
Pathogenic Yeast ◽  
Aspartic Proteases ◽  
Akt Activation ◽  
Tnf Α ◽  
Factor Alpha ◽  
Pepstatin A

ABSTRACT The secretion of aspartic proteases (Saps) has long been recognized as a virulence-associated trait of the pathogenic yeast Candida albicans. In this study, we report that different recombinant Saps, including Sap1, Sap2, Sap3, and Sap6, have differing abilities to induce secretion of proinflammatory cytokines by human monocytes. In particular Sap1, Sap2, and Sap6 significantly induced interleukin-1β (IL-1β), tumor necrosis factor alpha (TNF-α), and IL-6 production. Sap3 was able to stimulate the secretion of IL-1β and TNF-α. All Saps tested were able to induce Ca2+ influx in monocytes. Treatment of these Saps with pepstatin A did not have any effect on cytokine secretion, indicating that their stimulatory potential was independent from their proteolytic activity. The capacity of Saps to induce inflammatory cytokine production was also independent from protease-activated receptor (PAR) activation and from the optimal pH for individual Sap activity. The interaction of Saps with monocytes induced Akt activation and phosphorylation of IκBα, which mediates translocation of NF-κB into the nucleus. Overall, these results suggest that individual Sap proteins can induce an inflammatory response and that this phenomenon is independent from the pH of a specific host niche and from Sap enzymatic activity. The inflammatory response is partially dependent on Sap denaturation and is triggered by the Akt/NF-κB activation pathway. Our data suggest a novel, activity-independent aspect of Saps during interactions of C. albicans with the host.

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 Endogenous tumour necrosis factor-alpha sensitise melanoma cells to glucosaminylmuramyl dipeptide

FEBS Letters ◽  
1998 ◽  
Vol 426 (3) ◽  
pp. 373-376 ◽  
Author(s):  
Tatyana I Valyakina ◽  
Ravilya L Komaleva ◽  
Elena E Petrova ◽  
Alexander A Malakhov ◽  
Ol'ga G Shamborant ◽  
...  
Keyword(s):  
Tumour Necrosis Factor ◽  
Tumour Necrosis ◽  
Melanoma Cells ◽  
Tumour Necrosis Factor Alpha ◽  
Necrosis Factor Alpha ◽  
Factor Alpha ◽  
Necrosis Factor

scholarly journals Filamin A Links Sphingosine Kinase 1 and Sphingosine-1-Phosphate Receptor 1 at Lamellipodia To Orchestrate Cell Migration

2008 ◽  
Vol 28 (18) ◽  
pp. 5687-5697 ◽  
Author(s):  
Michael Maceyka ◽  
Sergio E. Alvarez ◽  
Sheldon Milstien ◽  
Sarah Spiegel
Keyword(s):  
Critical Role ◽  
Cell Movement ◽  
Sphingosine Kinase ◽  
Lipid Mediator ◽  
Sphingosine Kinase 1 ◽  
Filamin A ◽  
Interacting Protein ◽  
Surface Receptors ◽  
Sphingosine 1 Phosphate ◽  
Lamellipodia Formation

ABSTRACT Sphingosine kinase 1 (SphK1) catalyzes the phosphorylation of sphingosine to produce the potent lipid mediator sphingosine-1-phosphate (S1P), which plays a critical role in cell motility via its cell surface receptors. Here, we have identified filamin A (FLNa), an actin-cross-linking protein involved in cell movement, as a bona fide SphK1-interacting protein. Heregulin stimulated SphK1 activity only in FLNa-expressing A7 melanoma cells but not in FLNa-deficient cells and induced its translocation and colocalization with FLNa at lamellipodia. SphK1 was required for heregulin-induced migration, lamellipodia formation, activation of PAK1, and subsequent FLNa phosphorylation. S1P directly stimulated PAK1 kinase, suggesting that it may be a target of intracellularly generated S1P. Heregulin also induced colocalization of S1P1 (promotility S1P receptor) but not S1P2, with SphK1 and FLNa at membrane ruffles. Moreover, an S1P1 antagonist inhibited the lamellipodia formation induced by heregulin. Hence, FLNa links SphK1 and S1P1 to locally influence the dynamics of actin cytoskeletal structures by orchestrating the concerted actions of the triumvirate of SphK1, FLNa, and PAK1, each of which requires and/or regulates the actions of the others, at lamellipodia to promote cell movement.

Sphingosine-1-Phosphate Attenuates Lipopolysaccharide-Induced Pericyte Loss via Activation of Rho-A and MRTF-A

2020 ◽  
Author(s):  
Farah Abdel Rahman ◽  
Sascha d'Almeida ◽  
Tina Zhang ◽  
Morad Asadi ◽  
Tarik Bozoglu ◽  
...  
Keyword(s):  
Nuclear Translocation ◽  
Adherens Junctions ◽  
Lipid Mediator ◽  
Subsequent Increase ◽  
Perivascular Niche ◽  
Systemic Hypotension ◽  
Drastic Increase ◽  
Sphingosine 1 Phosphate ◽  
Related Transcription Factor ◽  
Pericyte Loss

AbstractThe high mortality seen in sepsis is caused by a systemic hypotension in part owing to a drastic increase in vascular permeability accompanied by a loss of pericytes. As has been shown previously, pericyte retention in the perivascular niche during sepsis can enhance the integrity of the vasculature and promote survival via recruitment of adhesion proteins such as VE-cadherin and N-cadherin. Sphingosine-1-phosphate (S1P) represents a lipid mediator regulating the deposition of the crucial adhesion molecule VE-cadherin at sites of interendothelial adherens junctions and of N-cadherin at endothelial–pericyte adherens junctions. Furthermore, in septic patients, S1P plasma levels are decreased and correlate with mortality in an indirectly proportional way. In the present study, we investigated the potential of S1P to ameliorate a lipopolysaccharide-induced septic hypercirculation in mice. Here we establish S1P as an antagonist of pericyte loss, vascular hyperpermeability, and systemic hypotension, resulting in an increased survival in mice. During sepsis S1P preserved VE-cadherin and N-cadherin deposition, mediated by a reduction of Src and cadherin phosphorylation. At least in part, this effect is mediated by a reduction of globular actin and a subsequent increase in nuclear translocation of MRTF-A (myocardin-related transcription factor A). These findings indicate that S1P may counteract pericyte loss and microvessel disassembly during sepsis and additionally emphasize the importance of pericyte–endothelial interactions to stabilize the vasculature.

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.

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