Objective. To investigate the prevalence of tumor necrosis factor receptor-associated periodic syndrome (TRAPS) among outpatients presenting with recurrent fevers and clinical features consistent with TRAPS.Methods. Mutational screening was performed in affected members of 18 families in which multiple members had symptoms compatible with TRAPS and in 176 consecutive subjects with sporadic (nonfamilial) "TRAPS-like" symptoms. Plasma concentrations of soluble tumor necrosis factor receptor superfamily 1A (sTNFRSF1A) were measured, and fluorescenceactivated cell sorter analysis was used to measure TNFRSF1A shedding from monocytes.Results. Eight novel and 3 previously reported TNFRSF1A missense mutations were identified, including an amino acid deletion (⌬D42) in a Northern Irish family and a C70S mutation in a Japanese family, both reported for the first time. Only 3 TNFRSF1A variants were found in patients with sporadic TRAPS (4 of 176 patients). Evidence for nonallelic heterogeneity in TRAPS-like conditions was found: 3 members of the "prototype familial Hibernian fever" family did not possess C33Y, present in 9 other affected members. Plasma sTNFRSF1A levels were low in TRAPS patients in whom renal amyloidosis had not developed, but also in mutation-negative symptomatic subjects in 4 families, and in 14 patients (8%) with sporadic TRAPS. Reduced shedding of TNFRSF1A from monocytes was demonstrated in vitro in patients with the T50M and T50K variants, but not in those with other variants.Conclusion. The presence of TNFRSF1A shedding defects and low sTNFRSF1A levels in 3 families without

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Objective. To investigate the molecular consequences of expressing mutated forms of tumor necrosis factor receptor I (TNFRI) as found in patients with TNFR-associated periodic syndrome (TRAPS).Methods. We cloned and expressed full-length wild-type (WT) and T50K and P46L variants of TNFRI using a new tightly regulated doxycycline-dependent expression system. This system enabled the study of molecular interactions between these receptors at both physiologic and pathophysiologic levels of expression.Results. We used chemical crosslinking on the cell surface to show that WT and mutant forms of TNFRI, derived from TRAPS patients, interact in the absence of TNF ligand. Doxycycline-controlled up-regulation of one TNFRI allele, either WT or mutant, caused downregulation of the other allele, indicating dynamic control of cell surface assembly. We also demonstrated that increased expression of mutant TNFRI (T50K) was associated with a parallel increase in NF-B p65 (RelA) subunit activation, which did not occur with increased expression of WT TNFRI.Conclusion. The T50K TRAPS-related variant is capable of sustaining inappropriate NF-B activation, resulting in persistent autoinflammation in target organs such as skin, synovial membrane, and the central nervous system. We conclude that some of the inflammatory processes seen in TRAPS do not involve direct interaction of TNF with its receptors, but that other proinflammatory mechanisms capable of up-regulating TNFRI expression may cause cellular activation through the NF-B signaling pathway.Tumor necrosis factor receptor-associated periodic syndrome (TRAPS; MIM no. 142680) is a dominantly inherited chronic inflammatory disorder caused by mutations in the extracellular domains of tumor necrosis factor receptor I (TNFRI), the gene for which is TNFRSF1A (1), and characterized by recurrent fevers and abdominal pain. The most common mutations involve cysteine residues, but several variants involving other residues have also been reported (1,2). More than 30 different pathogenic TNFRSF1A mutations have now been identified (see http://fmf.igh.cnrs.fr/infevers/ and ref.2), mostly located in either the first or second cysteine-rich N-terminal extracellular domain (CRD1 or CRD2) of TNFRSF1A (2,3). Impaired cleavage of the TNFRI (p55) ectodomain upon cellular activation has been demonstrated as a pathogenic mechanism in some but not all TNFRI variants (3-6) and did not relate to the severity of the phenotype (7,8).Biologic activities of TNF are mediated through 2 TNFRs, TNFRI and TNFRII (TNFR superfamily 1B

DNA origami nanoarrays with cell surface receptor ligands for cellular studies of human cutaneous melanoma cells and neonatal rat cardiomyocytes.