55-kDa Tumor Necrosis Factor Receptor Research Articles

First case of somatic mosaicism in TRAPS caused by a novel 24 nucleotides deletion in the TNFRSF1A gene

TNF receptor associated periodic syndrome (TRAPS) is an autosomal dominant disease caused by gain-of-function mutations in the TNF superfamily receptor 1A (TNFRSF1A) gene encoding 55 kDa TNF receptor type I (TNFR1). TRAPS is characterized by episodes of fever accompanied by severe abdominal pain, arthralgia, myalgia, rash, chest pain, enlarged glands and red, swollen eyes. Duration of the attacks can range from few days to several weeks, with the onset from early childhood to adulthood.

THU0376 Serum leptin, resistin, visfatin and adiponectin levels in tumor necrosis factor receptor-associated periodic syndrome (TRAPS)

BackgroundWhite adipose tissue produces more than 50 adipokines and other molecules that participate through endocrine, paracrine, autocrine or juxtacrine mechanisms of action in a wide variety of physiopathological processes, including...

AB0252 Traps syndrome in a three generation greek family with long lasting recurrent fevers

BackgroundTumor necrosis factor receptor associated periodic fever syndrome (TRAPS) is an autosomal dominant inherited periodic fever syndrome caused by mutation of the 55kDa TNF receptor superfamily A1 gene,TNFRSF1A.TRAPS is defined...

OP0256 Involvement of unfolded protein response and reactive oxygen species pathways in the pathogenesis of tumour necrosis factor receptor- associated periodic syndrome (TRAPS)

BackgroundTRAPS is caused by autosomal dominant mutations in the TNFR1 gene [1]. Many TRAPS mutations are associated with reduced cell surface TNFR1 expression leading to the proposed hypothesis of impaired...

Mechanism of Evenness Interrupted (Evi)-Exosome Release at Synaptic Boutons

Wnt signaling plays critical roles during synaptic development and plasticity. However, the mechanisms by which Wnts are released and travel to target cells are unresolved. During synaptic development, the secretion of Drosophila Wnt1, Wingless, requires the function of Evenness Interrupted (Evi)/Wls, a Wingless-binding protein that is secreted along with Wingless at the neuromuscular junction. Given that Evi is a transmembrane protein, these studies suggested the presence of a novel vesicular mechanism of trans-synaptic communication, potentially in the form of exosomes. To establish the mechanisms for the release of Evi vesicles, we used a dsRNA assay in cultured cells to screen for genes that when down-regulated prevent the release of Evi vesicles. We identified two proteins, Rab11 and Syntaxin 1A (Syx1A), that were required for Evi vesicle release. To determine whether the same mechanisms were used in vivo at the neuromuscular junction, we altered the activity of Rab11 and Syx1A in motoneurons and determined the impact on Evi release. We found that Syx1A, Rab11, and its effector Myosin5 were required for proper Evi vesicle release. Furthermore, ultrastructural analysis of synaptic boutons demonstrated the presence of multivesicular bodies, organelles involved in the production and release of exosomes, and these multivesicular bodies contained Evi. We also used mass spectrometry, electron microscopy, and biochemical techniques to characterize the exosome fraction from cultured cells. Our studies revealed that secreted Evi vesicles show remarkable conservation with exosomes in other systems. In summary, our observations unravel some of the in vivo mechanisms required for Evi vesicle release.

Elevated serum tumor necrosis factor-α and soluble tumor necrosis factor receptors correlate with aberrant energy metabolism in liver cirrhosis

Objective Protein–energy malnutrition is frequently observed in patients with liver cirrhosis and is associated with their poor prognosis. Tumor necrosis factor-α (TNF-α) is elevated in those patients and may contribute to the alterations of energy metabolism. Our aim was to characterize the aberrant energy metabolism in cirrhotic patients with regard to TNF-α. Methods Twenty-four patients (mean age 65 ± 6 y) with viral liver cirrhosis who did not have hepatocellular carcinoma or acute infections were studied. Twelve healthy volunteers were recruited after matching for age, gender, and body mass index with the patients and served as controls (59 ± 8 y). Serum levels of TNF-α, soluble 55-kDa TNF receptor (sTNF-R55), soluble 75-kDa TNF receptor (sTNF-R75), and leptin were determined by immunoassay. Substrate oxidation rates of carbohydrate and fat were estimated by indirect calorimetry after overnight bedrest and fasting. Results In cirrhotic patients, serum levels of TNF-α, sTNF-R55, and sTNF-R75 were significantly higher than those in the controls and correlated with the increasing grade of disease severity as defined by Child-Pugh classification. Serum leptin concentration was not different between cirrhotics and controls but correlated with their body mass index. The decrease in substrate oxidation rate of carbohydrate and the increase in substrate oxidation rate of fat significantly correlated with serum TNF-α, sTNF-R55, and sTNF-R75 concentrations. Conclusion Tumor necrosis factor-α might be associated with the aberrant energy metabolism in patients with liver cirrhosis.

An association between RBMX, a heterogeneous nuclear ribonucleoprotein, and ARTS-1 regulates extracellular TNFR1 release

The type I, 55-kDa tumor necrosis factor receptor (TNFR1) is released to the extracellular space by two mechanisms, the constitutive release of TNFR1 exosome-like vesicles and the inducible proteolytic cleavage of TNFR1 ectodomains. Both pathways appear to be regulated by an interaction between TNFR1 and ARTS-1 (aminopeptidase regulator of TNFR1 shedding). Here, we sought to identify ARTS-1-interacting proteins that modulate TNFR1 release. Co-immunoprecipitation identified an association between ARTS-1 and RBMX (RNA-binding motif gene, X chromosome), a 43-kDa heterogeneous nuclear ribonucleoprotein. RNA interference attenuated RBMX expression, which reduced both the constitutive release of TNFR1 exosome-like vesicles and the IL-1β-mediated inducible proteolytic cleavage of soluble TNFR1 ectodomains. Reciprocally, over-expression of RBMX increased TNFR1 exosome-like vesicle release and the IL-1β-mediated inducible shedding of TNFR1 ectodomains. This identifies RBMX as an ARTS-1-associated protein that regulates both the constitutive release of TNFR1 exosome-like vesicles and the inducible proteolytic cleavage of TNFR1 ectodomains.

G-Protein-Coupled Receptor 30 Mediates Estrogen's Nongenomic Effects after Hemorrhagic Shock and Trauma

G-Protein-Coupled Receptor 30 Mediates Estrogen's Nongenomic Effects after Hemorrhagic Shock and Trauma

The Brefeldin A-inhibited Guanine Nucleotide-exchange Protein, BIG2, Regulates the Constitutive Release of TNFR1 Exosome-like Vesicles

The type I, 55-kDa tumor necrosis factor receptor (TNFR1) is released from cells to the extracellular space where it can bind and modulate TNF bioactivity. Extracellular TNFR1 release occurs by two distinct pathways: the inducible proteolytic cleavage of TNFR1 ectodomains and the constitutive release of full-length TNFR1 in exosome-like vesicles. Regulation of both TNFR1 release pathways appears to involve the trafficking of cytoplasmic TNFR1 vesicles. Vesicular trafficking is controlled by ADP-ribosylation factors (ARFs), which are active in the GTP-bound state and inactive when bound to GDP. ARF activation is enhanced by guanine nucleotide-exchange factors that catalyze replacement of GDP by GTP. We investigated whether the brefeldin A (BFA)-inhibited guanine nucleotide-exchange proteins, BIG1 and/or BIG2, are required for TNFR1 release from human umbilical vein endothelial cells. Effects of specific RNA interference (RNAi) showed that BIG2, but not BIG1, regulated the release of TNFR1 exosome-like vesicles, whereas neither BIG2 nor BIG1 was required for the IL-1beta-induced proteolytic cleavage of TNFR1 ectodomains. BIG2 co-localized with TNFR1 in diffusely distributed cytoplasmic vesicles, and the association between BIG2 and TNFR1 was disrupted by BFA. Consistent with the preferential activation of class I ARFs by BIG2, ARF1 and ARF3 participated in the extracellular release of TNFR1 exosome-like vesicles in a nonredundant and additive fashion. We conclude that the association between BIG2 and TNFR1 selectively regulates the extracellular release of TNFR1 exosome-like vesicles from human vascular endothelial cells via an ARF1- and ARF3-dependent mechanism.

Deficiency of TNFR1 protects myocardium through SOCS3 and IL-6 but not p38 MAPK or IL-1β

Tumor necrosis factor-alpha (TNF-alpha) plays an important role in the development of heart failure. There is a direct correlation between myocardial function and myocardial TNF levels in humans. TNF may induce local inflammation to exert tissue injury. On the other hand, suppressors of cytokine signaling (SOCS) proteins have been shown to inhibit proinflammatory signaling. However, it is unknown whether TNF mediates myocardial inflammation via STAT3/SOCS3 signaling in the heart and, if so, whether this effect is through the type 1 55-kDa TNF receptor (TNFR1). We hypothesized that TNFR1 deficiency protects myocardial function and decreases myocardial IL-6 production via the STAT3/SOCS3 pathway in response to TNF. Isolated male mouse hearts (n = 4/group) from wild-type (WT) and TNFR1 knockout (TNFR1KO) were subjected to direct TNF infusion (500 pg.ml(-1).min(-1) x 30 min) while left ventricular developed pressure and maximal positive and negative values of the first derivative of pressure were continuously recorded. Heart tissue was analyzed for active forms of STAT3, p38, SOCS3 and SOCS1 (Western blot analysis), as well as IL-1beta and IL-6 (ELISA). Coronary effluent was analyzed for lactate dehydrogenase (LDH) activity. As a result, TNFR1KO had significantly better myocardial function, less myocardial LDH release, and greater expression of SOCS3 (percentage of SOCS3/GAPDH: 45 +/- 4.5% vs. WT 22 +/- 6.5%) after TNF infusion. TNFR1 deficiency decreased STAT3 activation (percentage of phospho-STAT3/STAT3: 29 +/- 6.4% vs. WT 45 +/- 8.8%). IL-6 was decreased in TNFR1KO (150.2 +/- 3.65 pg/mg protein) versus WT (211.4 +/- 26.08) mice. TNFR1 deficiency did not change expression of p38 and IL-1beta following TNF infusion. These results suggest that deficiency of TNFR1 protects myocardium through SOCS3 and IL-6 but not p38 MAPK or IL-1beta.

Gender differences in injury induced mesenchymal stem cell apoptosis and VEGF, TNF, IL-6 expression: Role of the 55 kDa TNF receptor (TNFR1)

Concomitant pro- and anti-inflammatory properties of bone marrow stem cells (BMSC) may be an important aspect of their ability to heal injured tissue. However, very few studies have examined whether gender differences exist in BMSC function. Indeed, it remains unknown whether gender differences exist in BMSC function and ability to resist apoptosis, and if so, whether TNF receptor 1 (TNFR1) plays a role in these differences. We hypothesized that TNFR1 ablation equalizes gender differences in bone marrow mesenchymal stem cell (MSC) apoptosis, as well as expression of vascular endothelial growth factor (VEGF), TNF and interleukin (IL)-6. Mouse MSCs from male wild type (WT), female WT, male TNFR1 knockouts (TNFR1KO) and female TNFR1KO were stressed by endotoxin 200 ng/ml or 1 h hypoxia. MSC activation was determined by measuring VEGF, TNF and IL-6 production (ELISA). Differences considered significant if p<0.05. LPS and hypoxia resulted in significant activation in all experimental groups compared to controls. Male WT demonstrated significantly greater TNF and IL-6 and significantly less VEGF release than female WT MSCs. However, release of TNF, IL-6 and VEGF in male TNFR1 knockouts differed from male WT, but was not different from female WT MSCs. Similarly apoptosis in hypoxic male TNFRIKO differed from male WT, but it was not different from apoptosis from WT female. Female WT did not differ in TNF, IL-6 and VEGF release compared to female TNFR1KO. Gender differences exist in injury induced BMSC VEGF, TNF and IL-6 expression. TNFR1 may autoregulate VEGF, TNF and IL-6 expression in males more than females. MSCs are novel therapeutic agents for organ protection, but further study of the disparate expression of VEGF, TNF and IL-6 in males and females as well as the role of TNFR1 in these gender differences is necessary to maximize this protection.

A practical guide for the use of biologic agents in the treatment of rheumatoid arthritis*

A practical guide for the use of biologic agents in the treatment of rheumatoid arthritis*

TNF and TNF Receptors in TRAPS

Tumor necrosis factor receptor associated periodic syndrome (TRAPS) is a hereditary auto-inflammatory periodic fever syndrome associated with autosomal dominant ectodomain mutations in the 55kDa tumor necrosis factor receptor (TNFRSF1A). Over forty mutations in TNFRSF1A are associated with TRAPS. Plasma levels of soluble TNFRSF1A (sTNFRSF1A) are abnormally low in TRAPS patients, as is shedding of TNFRSF1A by some patients leucocytes. It was hypothesised that a deficit in neutralisation of TNF by sTNFRSF1A in TRAPS might result in an increased sensitivity to the inflammatory effects of TNF. However, not all TRAPS-related TNFRSF1A mutations result in defective receptor shedding by leucocytes. We found that dermal fibroblasts, but not leucocytes, from TRAPS patients with C33Y mutation demonstrated reduced shedding of TNFRSF1A, and that shedding of both wild-type and mutant truncated TNFRSF1A from transfected cell lines was similar. It is unlikely that a defect in TNFRSF1A shedding fully explains the clinical features of TRAPS. We investigated the behaviour of TRAPS-related TNFRSF1A mutants compared with wildtype in transfected cell lines: the mutant forms of TNFRSF1A retained signalling functions, but showed abnormalities of intra-cellular trafficking and TNF binding suggestive of protein misfolding. The severity of the abnormalities were observed with different mutants correlated with the degree of penetrance and clinical severity. We hypothesise that aggregation and ligand-independent signalling of mutant TNFRSF1A may occur. The increased understanding of the genetic basis and pathophysiology of TRAPS has facilitated therapeutic advances in the clinical management of this condition, particularly the use of the TNF-neutralising agent etanercept. Keywords: second cysteine-rich domains (CRDs), mutations, TNFRSF1A gene, TNF receptorassociated death domain (TRADD), amyloidosis, recessive autoinflammatory disorder

What does tumour necrosis factor excess do to the immune system long term?

Members of the tumour necrosis factor (TNF)/TNF-receptor (TNF-R) superfamily coordinate the immune response at multiple levels. For example, TNF, LTα, LTβ and RANKL provide signals required for lymphoid neogenesis, CD27,...

The apoptosis inhibitory domain of FE65-like protein 1 regulates both apoptotic and caspase-independent programmed cell death mediated by tumor necrosis factor

Tumor necrosis factor (TNF) can induce caspase-dependent (apoptotic) and caspase-independent pathways to programmed cell death (PCD). Here, we demonstrate that stable transfection of a cDNA encompassing the C-terminal apoptosis inhibitory domain (AID) of FE65-like protein 1 into mouse L929 fibrosarcoma cells protects from caspase-independent as well as from apoptotic PCD induced by TNF. We show that the AID does not protect from caspase-independent PCD elicited by 1-methyl-3-nitro-1-nitrosoguanidine, suggesting that the AID might prevent cell death by affecting assembly of the death inducing signaling complex of the 55 kDa TNF receptor or clustering of the receptor itself. Interference with caspase-independent PCD mediated by the sphingolipid ceramide further increases protection conferred by the AID, as does the antioxidant butylated hydroxyanisole, implicating ceramide and reactive oxygen species as potential factors interacting with caspase-independent PCD regulated by the AID.

Proteasome inhibition induces TNFR1 shedding from human airway epithelial (NCI-H292) cells

The type 1 55-kDa TNF receptor (TNFR1) is an important modulator of lung inflammation. Here, we hypothesized that the proteasome might regulate TNFR1 shedding from human airway epithelial cells. Treatment of NCI-H292 human airway epithelial cells for 2 h with the specific proteasome inhibitor clasto-lactacystin beta-lactone induced the shedding of proteolytically cleaved TNFR1 ectodomains. Clasto-lactacystin beta-lactone also induced soluble TNFR1 (sTNFR1) release from the A549 pulmonary epithelial cell line, as well as from primary cultures of human small airway epithelial cells and human umbilical vein endothelial cells. Furthermore, sTNFR1 release induced by clasto-lactacystin beta-lactone was not a consequence of apoptosis or the extracellular release of TNFR1 exosome-like vesicles. The clasto-lactacystin beta-lactone-induced increase in TNFR1 shedding was associated with reductions in cell surface receptors and intracytoplasmic TNFR1 stores that were primarily localized to vesicular structures. As expected, the broad-spectrum zinc metalloprotease inhibitor TNF-alpha protease inhibitor 2 (TAPI-2) attenuated clasto-lactacystin beta-lactone-mediated TNFR1 shedding, which is consistent with its ability to inhibit the zinc metalloprotease-catalyzed cleavage of TNFR1 ectodomains. TAPI-2 also reduced TNFR1 on the cell surface and attenuated the clasto-lactacystin beta-lactone-induced reduction of intracytoplasmic TNFR1 vesicles. This suggests that TNFR1 shedding induced by clasto-lactacystin beta-lactone involves the zinc metalloprotease-dependent trafficking of intracytoplasmic TNFR1 vesicles to the cell surface. Together, these data are consistent with the conclusion that proteasomal activity negatively regulates TNFR1 shedding from human airway epithelial cells, thus identifying previously unrecognized roles for the proteasome and zinc metalloproteases in modulating the generation of sTNFRs.

Amino-terminal TACE prodomain attenuates TNFR2 cleavage independently of the cysteine switch

TNF-alpha-converting enzyme (TACE, ADAM17) cleaves membrane-associated cytokines and receptors and thereby regulates inflammatory and immune events, as well as lung development and mucin production. For example, the TACE-mediated cleavage of the type II 75-kDa TNF receptor (TNFR2) generates a soluble TNF-binding protein that modulates TNF bioactivity. TACE is synthesized as a latent proenzyme that is retained in an inactive state via an interaction between its prodomain and catalytic domain. Although the formation of an intramolecular bond between a cysteine in the prodomain and a zinc atom in the catalytic site had been thought to mediate this inhibitory activity, it was recently reported that the cysteine-switch motif is not required. Here, we hypothesized that the amino terminus of the TACE prodomain might contribute to the ability of the prodomain to maintain TACE in an inactive state independently of a cysteine-switch mechanism. We synthesized a 37-amino acid peptide corresponding to TACE amino acids 18-54 (N-TACE(18-54)) and assessed whether it possessed TACE inhibitory activity. In an in vitro model assay system, N-TACE(18-54) attenuated TACE-catalyzed cleavage of a TNFR2:Fc substrate. Furthermore, N-TACE(18-54) inhibited constitutive TNFR2 shedding from a human monocytic cell line by 42%. A 19-amino acid, leucine-rich domain, corresponding to TACE amino acids 30-48, demonstrated partial inhibitory activity. In summary, we have identified a subdomain within the amino terminus of the TACE prodomain that attenuates TACE catalytic activity independently of a cysteine-switch mechanism, which provides new insight into the regulation of TACE enzymatic activity.

Tumor necrosis factor (TNF) interferes with insulin signaling through the p55 TNF receptor death domain

Tumor necrosis factor (TNF) contributes to insulin resistance by binding to the 55 kDa TNF receptor (TNF-R55), resulting in serine phosphorylation of proteins such as insulin receptor (IR) substrate (IRS)-1, followed by reduced tyrosine phosphorylation of IRS-1 through the IR and, thereby, diminished IR signal transduction. Through independent receptor domains, TNF-R55 activates a neutral (N-SMase) and an acid sphingomyelinase (A-SMase), that both generate the sphingolipid ceramide. Multiple candidate kinases have been identified that serine-phosphorylate IRS-1 in response to TNF or ceramide. However, due to the fact that the receptor domain of TNF-R55 mediating inhibition of the IR has not been mapped, it is currently unknown whether TNF exerts these effects with participation of N-SMase or A-SMase. Here, we identify the death domain of TNF-R55 as responsible for the inhibitory effects of TNF on tyrosine phosphorylation of IRS-1, implicating ceramide generated by A-SMase as a downstream mediator of inhibition of IR signaling.

The Met-196 → Arg Variation of Human Tumor Necrosis Factor Receptor 2 (TNFR2) Affects TNF-α-induced Apoptosis by Impaired NF-κB Signaling and Target Gene Expression

Tumor necrosis factor-alpha (TNF-alpha)-induced signaling is pivotally involved in the pathogenesis of chronic inflammatory diseases. A polymorphism in the TNF receptor 2 (TNFR2) gene resulting in a juxtamembrane inversion from methionine (TNFR2(196MET)) to arginine (TNFR2(196ARG)) has been genetically associated with an increased risk for systemic lupus erythematosus and familial rheumatoid arthritis. Albeit the mutation does not affect the TNF binding kinetics of TNFR2, the present study provides evidence that the mutation results in a significantly lower capability to induce TNFR2-mediated NF-kappaB activation. Pretriggering of TNFR2 with a receptor-specific mutein leads to an enhancement of TNFR1-induced apoptosis, which is further increased in cells carrying the TNFR2(196ARG) variant. A diminished induction of NF-kappaB-dependent target genes conveying either anti-apoptotic or pro-inflammatory functions, such as cIAP1, TRAF1, IL-6, or IL-8 is observed. The mutated form TNFR2(196ARG) shows a reduction of inducible TRAF2 recruitment upon TNF-alpha stimulation. The findings suggest a common molecular mechanism for the involvement of the TNFR2(196ARG) variant in the etiopathogenesis of different chronic inflammatory disorders.

A novel mutation (T61I) in the gene encoding tumour necrosis factor receptor superfamily 1A (TNFRSF1A) in a Japanese patient with tumour necrosis factor receptor-associated periodic syndrome (TRAPS) associated with systemic lupus erythematosus.

To identify potential mutations in the tumour necrosis factor receptor superfamily 1A gene (TNFRSF1A) in a Japanese female patient with recurrent fever complicated by systemic lupus erythematosus (SLE), and in her family members. DNA sequencing of exons 1-10 of the TNFRSF1A gene was performed to determine mutations that might be associated with the tumour necrosis factor receptor-associated periodic syndrome (TRAPS). Moreover, the TNFRSF1A gene was examined in Japanese patients with autoimmune diseases, including SLE, rheumatoid arthritis (RA), mixed connective tissue disease (MCTD) and Behçet's disease, and in healthy Japanese controls. Enzyme-amplified sensitivity immunoassay (EASIA) analysis was used to assess serum levels of TNF, the 55-kDa TNF receptor (TNFRSF1A) and the 75-kDa TNF receptor (TNFRSF1B). Membrane TNFRSF1A expression was analysed on the surface of peripheral blood mononuclear cells by flow cytometry. A novel mutation, a heterozygous C to T transition in exon 3 which substitutes an isoleucine for a threonine at position 61 (T61I) was detected in the TNFRSF1A gene derived from the genomic DNA of a Japanese female TRAPS patient. Two nieces and one nephew, all with a similar clinical phenotype, also possessed the same TNFRSF1A mutation. We further demonstrated the same mutation in five of 60 SLE patients (8.3%) and in five of 120 healthy individuals (4.2%), with no significant differences. Although high titres of serum TNF and soluble TNFRSF1B protein were observed in this patient, low titres of soluble TNFRSF1A protein were detected. However, a defect in TNFRSF1A shedding in vitro was not observed in monocytes derived from this patient. This is the first report of a TRAPS patient associated with SLE with a novel TNFRSF1A mutation (T61I).