Reduced tumor necrosis factor signaling in primary human fibroblasts containing a tumor necrosis factor receptor superfamily 1A mutant

Abstract

Objective. Tumor necrosis factor receptorassociated periodic syndrome (TRAPS) is an autoinflammatory syndrome associated with mutations in the gene that encodes tumor necrosis factor receptor superfamily 1A (TNFRSF1A). The purpose of this study was to describe a novel TNFRSF1A mutation (C43S) in a patient with TRAPS and to examine the effects of this TNFRSF1A mutation on tumor necrosis factor ␣ (TNF␣)-induced signaling in a patient-derived primary dermal fibroblast line.Methods. TNFRSF1A shedding from neutrophils was measured by flow cytometry and enzyme-linked immunosorbent assay (ELISA). Primary dermal fibroblast lines were established from the patient with the C43S TRAPS mutation and from healthy volunteers. Activation of NF-B and activator protein 1 (AP-1) was evaluated by electrophoretic mobility shift assays. Cytokine production was measured by ELISA. Cell viability was measured by alamar blue assay. Apoptosis was measured by caspase 3 assay in the fibroblasts and by annexin V assay in peripheral blood mononuclear cells.Results. Activation-induced shedding of the TNFRSF1A from neutrophils was not altered by the C43S TRAPS mutation. TNF␣-induced activation of NF-B and AP-1 was decreased in the primary dermal fibroblasts with the C43S TNFRSF1A mutation. Nevertheless, the C43S TRAPS fibroblasts were capable of producing interleukin-6 (IL-6) and IL-8 in response to TNF␣. However, TNF␣-induced cell death and apoptosis were significantly decreased in the samples from the patient with the C43S TRAPS mutation.Conclusion. The C43S TNFRSF1A mutation results in decreased TNF␣-induced nuclear signaling and apoptosis. Our data suggest a new hypothesis, in that the C43S TRAPS mutation may cause the inflammatory phenotype by increasing resistance to TNF␣-induced apoptosis.

Neutrophils from patients with TNFRSF1A mutations display resistance to tumor necrosis factor–induced apoptosis: Pathogenetic and clinical implications

“…They showed a significant decrease of cell death after TNF stimulation in skin fibroblasts derived from 1 patient with the C43S TNFRSF1A substitution (25). In the present study, resistance to TNF-induced apoptosis and to caspase 8 expression was demonstrated in circulating neutrophils, which represent a cell subset closely related to the systemic inflammation occurring during the disease flares observed in TRAPS patients.…”

“…The actual relevance of the defect of shedding of TNFR p55 from the leukocyte membrane after cell activation has been challenged by the observation of a large variability of this phenomenon in accordance with the different TNFRSF1A mutations analyzed (5,8,11,25).…”

Abnormal disulfide-linked oligomerization results in ER retention and altered signaling by TNFR1 mutants in TNFR1-associated periodic fever syndrome (TRAPS)

“…In this light, it is intriguing that dermal fibroblasts from TRAPS patients were resistant to TNF-induced apoptosis. 37 This work has identified a common molecular basis for the altered receptor trafficking of TNFR1 mutants in TRAPS. The common theme of structural perturbation, oligomerization, and altered trafficking of all TNFR1 mutants studied here, combined with the fact that no TRAPS-associated TNFR1 mutations that result in loss of TNFR1 protein expression have been identified in TRAPS, suggests that the disease results from more than simple loss of normal TNF binding or reduced secretion of the mutant receptors.…”

Hereditary Periodic Fever Syndromes

“…[26][27][28][29] Moreover, recent studies indicate a number of other functional abnormalities in mutant p55 receptors, including altered intracellular trafficking, 30 impaired TNF binding, 30 and a defect in TNFinduced leukocyte apoptosis. 31 Patients with TRAPS generally do not respond to treatment with colchicine, which is highly effective in FMF, and, although they are responsive to high-dose corticosteroids, side effects are often limiting. The recognition of the role of the TNF-pathway has led to the introduction of etanercept, the soluble p75 TNFR:Fc fusion protein, in the treatment of TRAPS.…”