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Altered expression of adhesion molecules in immune cells has been demonstrated in rheumatoid arthritis (RA). Carcinoembryonic–antigen–related cell–adhesion molecule 1 (CEACAM1) is an adhesion molecule that acts as a coinhibitory receptor in the immune system. We investigated the role of CEACAM1 in immune cell subsets of patients with RA. Peripheral blood was obtained from 37 patients with RA and 20 healthy controls (HC). The expression of CEACAM1 and T–cell immunoglobulin mucin domain molecule (TIM) –3 on peripheral blood mononuclear cells and neutrophils was analyzed by flow cytometry. Intracellular TIM–3 expression was analyzed using cellular lysates by Western blot analysis. Serum levels of soluble CEACAM1 (sCEACAM1) were estimated by an enzyme-linked immunosorbent assay. CEACAM1 expression was not detected in peripheral blood mononuclear cells, including in CD14(+) monocytes and CD3(+) lymphocytes isolated from patients with RA or HC. However, substantial cell–surface expression of CEACAM1 was detected in peripheral blood neutrophils, and it was significantly elevated in samples from patients with RA without remission compared to those in remission. There was no significant difference in serum levels of sCEACAM1 between patients with RA and HC. Cell-surface expression of TIM-3 was not detected in peripheral blood neutrophils from patients with RA or HC but was seen in CD14(+) monocytes. However, there was no significant difference in TIM–3 expression on monocytes between patients with RA and HC. Our data indicate that cell-surface expression of CEACAM1 on peripheral blood neutrophils are higher in patients with RA and that it is associated with rheumatoid inflammation. Further studies are needed to explore the potential role of CEACAM1 in rheumatoid inflammatory pathways.

A20 (TNFAIP3) and ABIN-1 (TNIP1), two candidate inflammatory bowel disease (IBD) susceptibility genes, preserve intestinal homeostasis by cooperatively restricting intestinal epithelial cell death. A20 and ABIN-1 synergistically restrict both TNF-dependent and TNF-independent cell death., A20 (TNFAIP3) and ABIN-1 (TNIP1) are candidate susceptibility genes for inflammatory bowel disease and other autoimmune or inflammatory diseases, but it is unclear how these proteins interact in vivo to prevent disease. Here we show that intestinal epithelial cell (IEC)-specific deletion of either A20 or ABIN-1 alone leads to negligible IEC loss, whereas simultaneous deletion of both A20 and ABIN-1 leads to rapid IEC death and mouse lethality. Deletion of both A20 and ABIN-1 from enteroids causes spontaneous cell death in the absence of microbes or hematopoietic cells. Studies with enteroids reveal that A20 and ABIN-1 synergistically restrict death by inhibiting TNF-induced caspase 8 activation and RIPK1 kinase activity. Inhibition of RIPK1 kinase activity alone, or caspase inhibition combined with RIPK3 deletion, abrogates IEC death by blocking both apoptosis and necroptosis in A20 and ABIN-1 double-deficient cells. These data show that the disease susceptibility proteins A20 and ABIN-1 synergistically prevent intestinal inflammation by restricting IEC death and preserving tissue integrity.

We previously reported that IL-7−/−RAG−/− mice receiving naive T cells failed to induce colitis. Such abrogation of colitis may be associated with not only incomplete T cell maintenance due to the lack of IL-7, but also with the induction of colitogenic CD4+ T cell apoptosis at an early stage of colitis development. Moreover, NK cells may be associated with the suppression of pathogenic T cells in vivo, and they may induce apoptosis of CD4+ T cells. To further investigate these roles of NK cells, RAG−/− and IL-7−/−RAG−/− mice that had received naive T cells were depleted of NK cells using anti-asialo GM1 and anti-NK1.1 Abs. NK cell depletion at an early stage, but not at a later stage during colitogenic effector memory T cell (TEM) development, resulted in exacerbated colitis in recipient mice even in the absence of IL-7. Increased CD44+CD62L− TEM and unique CD44−CD62L− T cell subsets were observed in the T cell-reconstituted RAG−/− recipients when NK cells were depleted, although Fas, DR5, and IL-7R expressions in this subset differed from those in the CD44+CD62L− TEM subset. NK cell characteristics were the same in the presence or absence of IL-7 in vitro and in vivo. These results suggest that NK cells suppress colitis severity in T cell-reconstituted RAG−/− and IL-7−/−RAG−/− recipient mice through targeting of colitogenic CD4+CD44+CD62L− TEM and, possibly, of the newly observed CD4+CD44−CD62L− subset present at the early stage of T cell development.

A 69-year-old man with autoimmune hepatitis (AIH) was admitted to hospital with high fever and cough. Chest roentgenogram and computed tomography showed pleural and pericardial effusion. Serological tests showed a high titer of antinuclear antibodies and positive anti-DNA antibody and lymphocytopenia. He fulfilled the American College of Rheumatology criteria for systemic lupus erythematosus (SLE). After administration of corticosteroids, his symptoms and liver dysfunction improved. To the authors' knowledge, this is the first male case of overlap between AIH and late-onset SLE.

SummaryInappropriate inflammasome activation contributes to multiple human diseases, but the mechanisms by which inflammasomes are suppressed are poorly understood. The NF-κB inhibitor A20 is a ubiquitin-modifying enzyme that might be critical in preventing human inflammatory diseases. Here, we report that A20-deficient macrophages, unlike normal cells, exhibit spontaneous NLRP3 inflammasome activity to LPS alone. The kinase RIPK3, but not the adaptor MyD88, is required for this response. In normal cells, A20 constitutively associates with caspase-1 and pro-IL-1β, and NLRP3 activation further promotes A20 recruitment to the inflammasome. Pro-IL-1β also co-immunoprecipitates with RIPK1, RIPK3, caspase-1, and caspase-8 in a complex that is modified with K63-linked and unanchored polyubiquitin. In A20-deficient macrophages, this pro-IL-1β-associated ubiquitination is markedly increased in a RIPK3-dependent manner. Mass spectrometric and mutational analyses reveal that K133 of pro-IL-1β is a physiological ubiquitination site that supports processing. Our study reveals a mechanism by which A20 prevents inflammatory diseases.

Inflammatory bowel diseases encompass gastrointestinal illnesses typified by chronic inflammation, loss of epithelial integrity and gastrointestinal microbiota dysbiosis. In an effort to counteract these characteristic perturbations, we used stem cells and/or a probiotic therapy in a murine model of Dextran Sodium Sulfate induced colitis to examine both their efficacy in ameliorating disease and impact on niche-specific microbial communities of the lower GI tract. Colitis was induced in C57BL/6 mice by administering 3% DSS in drinking water for 10 days prior to administering one of three treatment plans: daily probiotic (VSL#3) supplementation for 3 days, a single tail vein injection of 1x10 (6) murine mesenchymal stem cells, or both. Ileal, cecal and colonic sections were collected for microbiota and histological analyses. Microbiota profiling revealed distinct bacterial community compositions in the ileum, cecum and colon of control untreated animals, all of which were predicted in silico to be enriched for a number of discrete KEGG pathways, indicating compositional and functional niche specificity in healthy animals. DSS-treatment perturbed community composition in all three niches with ileal communities exhibiting the greatest change relative to control animals. Each treatment group exhibited treatment-specific alterations in microbiota composition in the lower GI tract, though disease scores were only improved in VSL#3-treated animals. The ileal microbiota were most profoundly altered in composition in this group of animals and characterized by significant Enterobacteriaceae enrichment compared with colitic mice (P

It has been suggested that prolonged inflammatory bowel diseases (IBD) may lead to colitis-associated carcinogenesis (CAC). We previously observed that the NF-κB activation in colonic epithelial cells is associated with increased tumor necrosis factor receptor 2 (TNFR2) expression in CAC development. However, the mechanism by which epithelial NF-κB activation leading to CAC is still unclear. Myosin light chain kinase (MLCK) has been reported to be responsible for the epithelial permeability associated with TNF signaling. Therefore we focused on the role of MLCK expression via TNFR2 signaling on CAC development. Pro-tumorigenic cytokines such as IL-1β, IL-6 and MIP-2 production as well as INF-γ and TNF production at the lamina propria were increased in the setting of colitis, and further in tumor tissues in associations with up-regulated TNFR2 and MLCK expressions in the epithelial cells of a CAC model. The up-regulated MLCK expression was observed in TNF-stimulated colonic epithelial cells in a dose-dependent fashion in association with up-regulation of TNFR2. Silencing TNFR2, but not TNFR1, resulted in restoration of epithelial tight junction (TJ) associated with decreased MLCK expression. Antibody-mediated blockade of TNF signaling also resulted in restoration of TJ in association with suppressed MLCK expression, and interestingly, similar results were observed with suppressing TNFR2 and MLCK expressions by inhibiting MLCK in the epithelial cells. Silencing of MLCK also resulted in suppressed TNFR2, but not TNFR1, expression, suggesting that the restored TJ leads to reduced TNFR2 signaling. Such suppression of MLCK as well as blockade of TNFR2 signaling resulted in restored TJ, decreased pro-tumorigenic cytokines and reduced CAC development. These results suggest that MLCK may be a potential target for the prevention of IBD-associated tumor development.

The microRNA miR-210 is a signature of hypoxia. We found robust increase in the abundance of miR-210 (>100-fold) in activated T cells, especially in the TH17 lineage of helper T cells. Hypoxia acted in synergy with stimulation via the T cell antigen receptor (TCR) and coreceptor CD28 to accelerate and increase Mir210 expression. Mir210 was directly regulated by HIF-1α, a key transcriptional regulator of TH17 polarization. Unexpectedly, we identified Hif1a as a target of miR-210, which suggested negative feedback by miR-210 in inhibiting HIF-1α expression. Deletion of Mir210 promoted TH17 differentiation under conditions of limited oxygen. In experimental colitis, miR-210 reduced the abundance of Hif1a transcripts and the proportion of cells that produced inflammatory cytokines and controlled disease severity. Our study identifies miR-210 as an important regulator of T cell differentiation in hypoxia, which can limit immunopathology.

Treatment with anti-TNF-alpha MAb has been accepted as a successful maintenance therapy for patients with inflammatory bowel diseases (IBD). Moreover, it has been recently reported that blockade of TNF receptor (TNFR) 1 signaling in infiltrating hematopoietic cells may prevent the development of colitis-associated cancer (CAC). However, it remains unclear whether the TNF-alpha signaling in epithelial cells is involved in the development of CAC. To investigate this, we studied the effects of anti-TNF-alpha MAb in an animal model of CAC by administration of azoxymethane (AOM) followed by sequential dextran sodium sulfate (DSS) ingestion. We observed that the NF-kappaB pathway is activated in colonic epithelia from DSS-administered mice in association with upregulation of TNFR2 rather than TNFR1. Immunoblot analysis also revealed that the TNFR2 upregulation accompanied by the NF-kappaB activation is further complicated in CAC tissues induced in AOM/DSS-administered mice compared with the nontumor area. Such NF-kappaB activity in the epithelial cells is significantly suppressed by the treatment of MP6-XT22, an anti-TNF-alpha MAb. Despite inability to reduce the severity of colitis, sequential administration of MP6-XT22 reduced the numbers and size of tumors in association with the NF-kappaB inactivation. Taken together, present studies suggest that the TNFR2 signaling in intestinal epithelial cells may be directly involved in the development of CAC with persistent colitis and imply that the maintenance therapy with anti-TNF-alpha MAb may prevent the development of CAC in patients with long-standing IBD.

Nat. Immunol. 16, 618–627 (2015); published online 4 May 2015; corrected after print 21 May 2015 In the version of this article initially published, the filled circles in Figure 3b were incorrectly labeled 'A20+/flCD4-Cre'. The correct label is 'A20fl/flCD4-Cre'. The error has been corrected in the HTML and PDF versions of the article.

A 23-year-old woman was admitted to our hospital with jaundice and hepatic coma. She had taken a weight-loss supplement for one month before admission. Her clinical and laboratory findings were consistent with fulminant hepatic failure and fulfilled the criteria of autoimmune hepatitis. Despite corticosteroid pulse therapy and plasma exchange, her symptoms and laboratory findings deteriorated. Her condition improved after she received a living donor-liver transplant from her sister. Autoimmune hepatitis usually follows a chronic course, but it should be considered a type of fulminant hepatic failure and treated promptly.