Loss-of-function mutations in TNFAIP3 leading to A20 haploinsufficiency cause an early-onset autoinflammatory disease

Systemic autoinflammatory diseases are driven by abnormal activation of innate immunity. Herein we describe a new disease caused by high-penetrance heterozygous germline mutations in TNFAIP3, which encodes the NF-B regulatory protein A20, in six unrelated families with early-onset systemic inflammation. The disorder resembles Behçet\u27s disease, which is typically considered a polygenic disorder with onset in early adulthood. A20 is a potent inhibitor of the NF-B signaling pathway. Mutant, truncated A20 proteins are likely to act through haploinsufficiency because they do not exert a dominant-negative effect in overexpression experiments. Patient-derived cells show increased degradation of IBα and nuclear translocation of the NF-B p65 subunit together with increased expression of NF-B-mediated proinflammatory cytokines. A20 restricts NF-B signals via its deubiquitinase activity. In cells expressing mutant A20 protein, there is defective removal of Lys63-linked ubiquitin from TRAF6, NEMO and RIP1 after stimulation with tumor necrosis factor (TNF). NF-B-dependent proinflammatory cytokines are potential therapeutic targets for the patients with this disease

Myeloid lineage-restricted somatic mosaicism of NLRP3 mutations in patients with variant Schnitzler syndrome

Contains fulltext : 153462.pdf (publisher's version ) (Closed access

The dectin-1/inflammasome pathway is responsible for the induction of protective T-helper 17 responses that discriminate between yeasts and hyphae of Candida albicans

Contains fulltext : 96420.pdf (publisher's version ) (Open Access)In the mucosa, the immune pathways discriminating between colonizing and invasive Candida, thus inducing tolerance or inflammation, are poorly understood. Th17 responses induced by Candida albicans hyphae are central for the activation of mucosal antifungal immunity. An essential step for the discrimination between yeasts and hyphae and induction of Th17 responses is the activation of the inflammasome by C. albicans hyphae and the subsequent release of active IL-1beta in macrophages. Inflammasome activation in macrophages results from differences in cell-wall architecture between yeasts and hyphae and is partly mediated by the dectin-1/Syk pathway. These results define the dectin-1/inflammasome pathway as the mechanism that enables the host immune system to mount a protective Th17 response and distinguish between colonization and tissue invasion by C. albicans

A Comparison Of The Microleakage Of Direct Composite Resin Restorations And Composite Resin Inlays - In Vitro

OBJECTIVES: Autoinflammatory disorders are disorders of the innate immune system. Standard genetic testing provided no correct diagnosis in a female patient from a non-consanguineous family of British descent with a colchicine-responsive autosomal dominant periodic fever syndrome. We aimed to unravel the genetic cause of the symptoms. METHODS: Whole exome sequencing was used to screen for novel sequence variants, which were validated by direct Sanger sequencing. Ex vivo stimulation with peripheral blood mononuclear cells was performed to study the functional consequences of the mutation. mRNA and cytokine levels were measured by quantitative PCR and ELISA, respectively. RESULTS: Whole exome sequencing revealed a novel missense sequence variant, not seen in around 6800 controls, mapping to exon 8 of the MEFV gene (c.1730C>A; p.T577N), co-segregating perfectly with disease in this family. Other mutations at the same amino acid (c.1730C>G; p.T577S and c.1729A>T; p.T577S) were found in a family of Turkish descent, with autosomal dominant inheritance of familial Mediterranean fever (FMF)-like phenotype, and a Dutch patient, respectively. Moreover, a mutation (c.1729A>G; p.T577A) was detected in two Dutch siblings, who had episodes of inflammation of varying severity not resembling FMF. Peripheral blood mononuclear cells from one patient of the index family showed increased basal interleukin 1β mRNA levels and cytokine responses after lipopolysaccharide stimulation. Responses normalised with colchicine treatment. CONCLUSIONS: Heterozygous mutations at amino acid position 577 of pyrin can induce an autosomal dominant autoinflammatory syndrome. This suggests that T577, located in front of the C-terminal B30.2/SPRY domain, is crucial for pyrin function

Inflammasome-independent modulation of cytokine response by autophagy in human cells

Contains fulltext : 98007.pdf (publisher's version ) (Open Access)Autophagy is a cell housekeeping mechanism that has recently received attention in relation to its effects on the immune response. Genetic studies have identified candidate loci for Crohn's disease susceptibility among autophagy genes, while experiments in murine macrophages from ATG16L1 deficient mice have shown that disruption of autophagy increases processing of IL-1beta and IL-18 through an inflammasome-dependent manner. Using complementary approaches either inducing or inhibiting autophagy, we describe modulatory effects of autophagy on proinflammatory cytokine production in human cells. Inhibition of basal autophagy in human peripheral blood mononuclear cells (PBMCs) significantly enhances IL-1beta after stimulation with TLR2 or TLR4 ligands, while at the same time reducing the production of TNFalpha. In line with this, induction of autophagy by starvation inhibited IL-1beta production. These effects of autophagy were not exerted at the processing step, as inflammasome activation was not influenced. In contrast, the effect of autophagy on cytokine production was on transcription level, and possibly involving the inhibition of p38 mitogen activated protein kinase (MAPK) phosphorylation. In conclusion, autophagy modulates the secretion of proinflammatory cytokines in human cells through an inflammasome-independent pathway, and this is a novel mechanism that may be targeted in inflammatory diseases

Modulation of inflammatory cytokine production by autophagy inhibition.

<p>Freshly isolated human PBMCs were pre-incubated for 1 hour at 37°C in culture medium in the presence or absence of 3MA (10 mM) and afterwards stimulated with culture medium, LPS (10 ng/ml) or Pam3Cys (10 µg/ml). After 24 hours incubation, IL-1β (A), TNFα (B) and IL-10 (C) were measured in the supernatant by specific ELISA. Data are presented as means ± SEM of cells harvested from 15 volunteers, **p<0.01, ***p<0.001.</p

The influence of 3MA on the ATP-dependent release of IL-1β.

<p>PBMCs were pre-incubated for 1 hour in the presence or absence of 3MA and were stimulated for 4 hours with LPS (10 ng/ml). After the stimulation, supernatants were discarded and refreshed with RPMI or with RPMI containing 1 mM ATP and cells were incubated for another 15 min. Data are shown as mean ± SEM of supernatant IL-1β levels obtained in 8 volunteers, **p<0.01.</p