Faecalibacterium prausnitzii Skews Human DC to Prime IL10-Producing T Cells Through TLR2/6/JNK Signaling and IL-10, IL-27, CD39, and IDO-1 Induction

The human colonic mucosa contains regulatory type 1-like (Tr1-like, i.e., IL-10-secreting and Foxp3-negative) T cells specific for the gut Clostridium Faecalibacterium prausnitzii (F. prausnitzii), which are both decreased in Crohn's disease patients. These data, together with the demonstration, in mice, that colonic regulatory T cells (Treg) induced by Clostridium bacteria are key players in colon homeostasis, support a similar role for F. prausnitzii-specific Treg in the human colon. Here we assessed the mechanisms whereby F. prausnitzii induces human colonic Treg. We demonstrated that F. prausnitzii, but not related Clostridia, skewed human dendritic cells to prime IL-10-secreting T cells. Accordingly, F. prausnitzii induced dendritic cells to express a unique array of potent Tr1/Treg polarizing molecules: IL-10, IL-27, CD39, IDO-1, and PDL-1 and, following TLR4 stimulation, inhibited their up-regulation of costimulation molecules as well as their production of pro-inflammatory cytokines IL-12 (p35 and p40) and TNFα. We further showed that these potent tolerogenic effects relied on F. prausnitzii-induced TLR2/6 triggering, JNK signaling and CD39 ectonucleotidase activity, which was induced by IDO-1 and IL-27. These data, together with the presence of F. prausnitzii-specific Tr1-like Treg in the human colon, point out to dendritic cells polarization by F. prausnitzii as the first described cellular mechanism whereby the microbiota composition may affect human colon homeostasis. Identification of F. prausnitzii-induced mediators involved in Tr1-like Treg induction by dendritic cells opens therapeutic avenues for the treatment of inflammatory bowel diseases

Factors affecting outcomes in Crohn's disease over 15 years

International audienc

Impact on Life Expectancy of Withdrawing Thiopurines in Patients with Crohn’s Disease in Sustained Clinical Remission: A Lifetime Risk-Benefit Analysis

Berenice Study GroupInternational audienceObjectiveLong-term treatment with thiopurines is associated with a decreased risk of Crohn’s disease (CD) flare but an increased risk of various cancers depending on gender, age, and presence of extensive colitis. We evaluated risks and benefits of withdrawing thiopurines in patients with CD in prolonged remission.MethodsWe developed a Markov model assessing risks and benefits of withdrawing thiopurines compared to continuing thiopurines in a lifetime horizon. The model was stratified by age (35 and 65 years old at thiopurine withdrawal), gender and presence of extensive colitis. Parameter estimates were taken from French cohorts and hospital databases, cancer and death national registries and published literature. Life expectancy, rates of relapse, serious adverse events, and causes-of-death were evaluated.ResultsIn patients without extensive colitis, continuing thiopurines increased life expectancy up to 0.03 years for 35 year-old men and women but decreased life expectancy down to 0.07 years for 65 year-old men and women. Withdrawal strategy became the preferred strategy at 40.6 years for men, and 45.7 years for women without extensive colitis. In patients with extensive colitis, continuation strategy was the preferred strategy regardless of age. Risk-benefit analysis was not modified by duration of CD activity.ConclusionsFactors determining life expectancy associated with withdrawal or continuation of thiopurines in patients with CD and in sustained clinical remission vary substantially according to gender, age and presence of extensive colitis. Individual decisions to continue or withdraw thiopurines in patients with CD in sustained remission should take into account these parameters

NLRP6 controls pulmonary inflammation from cigarette smoke in a gut microbiota-dependent manner

Chronic obstructive pulmonary disease (COPD) is a major health issue primarily caused by cigarette smoke (CS) and characterized by breathlessness and repeated airway inflammation. NLRP6 is a cytosolic innate receptor controlling intestinal inflammation and orchestrating the colonic host–microbial interface. However, its roles in the lungs remain largely unexplored. Using CS exposure models, our data show that airway inflammation is strongly impaired in Nlrp6-deficient mice with drastically fewer recruited neutrophils, a key cell subset in inflammation and COPD. We found that NLRP6 expression in lung epithelial cells is important to control airway and lung tissue inflammation in an inflammasome-dependent manner. Since gut-derived metabolites regulate NLRP6 inflammasome activation in intestinal epithelial cells, we investigated the link between NLRP6, CS-driven lung inflammation, and gut microbiota composition. We report that acute CS exposure alters gut microbiota in both wild-type (WT) and Nlrp6-deficient mice and that antibiotic treatment decreases CS-induced lung inflammation. In addition, gut microbiota transfer from dysbiotic Nlrp6-deficient mice to WT mice decreased airway lung inflammation in WT mice, highlighting an NLRP6-dependent gut-to-lung axis controlling pulmonary inflammation

Faecalibacterium prausnitzii A2-165 has a high capacity to induce IL-10 in human and murine dendritic cells and modulates T cell responses

Acknowledgements This work was financially supported by the EC FP7 Cross-talk project (PITN-GA-2008-215553). The authors thank the Histology Platform from GABI research unit and especially Abdelhak Boukadiri for their technical support in the histology sample preparation and Marlène Héry, Charline Pontlevoy, Jerome Pottier and André Tiffoche (UE0907 IERP, Jouy en Josas) for their help during animal experiments. The authors thank Rafael Muñoz-Tamayo (INRA) for his help in performing the PCA.Peer reviewedPublisher PD

230: Heightened risk of coronary atheroma conferred by a decrease in the plasma concentrations of lithocholic acid

ContextThe bile acids receptors Farsenoid X and TGR5 protect against the formation of atheroma in mice, though no evidence have linked coronary atheroma and bile acid in human. Bile acids links these receptors with more or less efficient activation, depending on the species.ObjectiveTo test the hypothesis that changes in concentrations of circulating bile acid species influence the risk of developing coronary atheromas in humans.MethodsPilot, prospective, observational study conducted between June and September 2010. The serum concentrations of cholic, chenodeoxycholic, deoxycholic, and lithocholic acids were measured in a fasting blood sample. Consecutive hospitalized or ambulatory patients undergoing emergency or elective coronary angiograms were eligible for inclusion. Post-cardiac arrest and non-fasting states, hepatic disease, and treatment with antimicrobials, corticosteroids, statins or fibrates were exclusion criteria. Of 393 screened patients, 44 met the study entry criteria, and were divided between 27 patients with (Group A) and 17 without (Group B) angiographically visible coronary atheromas. The pool of circulating bile acids was analyzed to measure the plasmatic concentrations of 28 different bile acid species. The variables associated with the presence of angiographically visible coronary atheromas were examined by single and multiple variable logistic regression analysis.ResultsThe serum lithocholic acid concentration was significantly lower in group A than in group B. By multiple variable analysis, lithocholic acid was the only predictor of coronary atheroma independently of patient gender (odds ratio 2.41 per 0.05 decrease; 95% confidence interval 1.11 to 5.25, P=0.027ConclusionA low serum concentration of lithocholic acid was an independent predictor of coronary atheroma in human

An Image-Based Genetic Assay Identifies Genes in T1D Susceptibility Loci Controlling Cellular Antiviral Immunity in Mouse

The pathogenesis of complex diseases, such as type 1 diabetes (T1D), derives from interactions between host genetics and environmental factors. Previous studies have suggested that viral infection plays a significant role in initiation of T1D in genetically predisposed individuals. T1D susceptibility loci may therefore be enriched in previously uncharacterized genes functioning in antiviral defense pathways. To identify genes involved in antiviral immunity, we performed an image-based high-throughput genetic screen using short hairpin RNAs (shRNAs) against 161 genes within T1D susceptibility loci. RAW 264.7 cells transduced with shRNAs were infected with GFP-expressing herpes simplex virus type 1 (HSV-1) and fluorescent microscopy was performed to assess the viral infectivity by fluorescence reporter activity. Of the 14 candidates identified with high confidence, two candidates were selected for further investigation, Il27 and Tagap. Administration of recombinant IL-27 during viral infection was found to act synergistically with interferon gamma (IFN-γ) to activate expression of type I IFNs and proinflammatory cytokines, and to enhance the activities of interferon regulatory factor 3 (IRF3). Consistent with a role in antiviral immunity, Tagap-deficient macrophages demonstrated increased viral replication, reduced expression of proinflammatory chemokines and cytokines, and decreased production of IFN-β. Taken together, our unbiased loss-of-function genetic screen identifies genes that play a role in host antiviral immunity and delineates roles for IL-27 and Tagap in the production of antiviral cytokines

TÍPICAS EN LA RECEPCIÓN A MR. TUBMAN [Material gráfico]

Copia digital. Madrid : Ministerio de Educación, Cultura y Deporte. Subdirección General de Coordinación Bibliotecaria, 201

Extra-intestinal malignancies in inflammatory bowel disease: Results of the 3rd ECCO Pathogenesis Scientific Workshop (III)

AbstractThe incidence of lymphoproliferative disorders (LD) is increasing in developed countries. Patients with inflammatory bowel disease (IBD) exposed to thiopurines are at additional risk of three specific forms of LD: Epstein-Barr-Virus-related post-transplant like LD, hepato-splenic T-cell lymphoma and post-mononucleosis lymphoproliferation. The risk of the two latter forms of LD can be reduced when considering specific immunosuppressive strategies in young males. It is still unclear whether the risk of uterine cervix abnormalities is increased in IBD women, irrespective of the use of immunosuppressants. Given the excess risk demonstrated in various other contexts of immunosuppression, it is currently recommended that all women with IBD, particularly those receiving immunosuppressants, strictly adhere to a screening program of cervical surveillance and undergo vaccination against HPV, when appropriate. Patients with IBD receiving immunosuppressants are at increased risk of skin cancers. The risk of non-melanoma skin cancer is notably increased in patients receiving thiopurines. Recent data suggest that the risk of melanoma is mildly increased in patients exposed to anti-TNF therapy. All IBD patients should adhere to a program of sun protection and dermatological surveillance, whose details should take into account the other non-IBD-related risk factors

Inhibitory Effect of Ursodeoxycholic Acid on Clostridium difficile Germination Is Insufficient to Prevent Colitis: A Study in Hamsters and Humans

Introduction: Bile acids (BA) influence germination and growth of Clostridium difficile. Ursodeoxycholic acid (UDCA), a BA minor in human, used for cholestatic liver diseases, inhibits germination and growth of C. difficile in vitro, but was never tested in vivo with an infectious challenge versus control. We hypothesized that UDCA could prevent CDI. We evaluated the effects of UDCA on C. difficile in vitro and in hamsters, with pharmacokinetics study and with an infectious challenge. Then, we studied CDI incidence in UDCA–treated patients.Methods: We evaluated germination and growth of C. difficile, with 0.01, 0.05, and 0.1% UDCA. We analyzed fecal BA of hamsters receiving antibiotics and UDCA (50 mg/kg/day), antibiotics, or UDCA alone. Then, we challenged with spores of C. difficile at D6 hamsters treated with UDCA (50 mg/kg/day) from D1 to D13, versus control. In human, we analyzed the database of a cohort on CDI in acute flares of inflammatory bowel disease (IBD). As PSC-IBD patients were under UDCA treatment, we compared PSC-IBD patients to IBD patients without PSC.Results:In vitro, UDCA inhibited germination and growth of C. difficile at 0.05 and 0.1%, competing with 0.1% TCA (with 0.1%: 0.05% ± 0.05% colony forming unit versus 100% ± 0%, P < 0.0001). In hamsters, UDCA reached high levels only when administered with antibiotics (43.5% UDCA at D5). Without antibiotics, UDCA was in small amount in feces (max. 4.28%), probably because of UDCA transformation into LCA by gut microbiota. During infectious challenge, mortality was similar in animals treated or not with UDCA (62.5%, n = 5/8, P = 0.78). UDCA percentage was high, similar and with the same kinetics in dead and surviving hamsters. However, dead hamsters had a higher ratio of primary over secondary BA compared to surviving hamsters. 9% (n = 41/404) of IBD patients without PSC had a CDI, versus 25% (n = 4/12) of PSC-IBD patients treated with UDCA.Conclusion: We confirmed the inhibitory effect of UDCA on growth and germination of C. difficile in vitro, with 0.05 or 0.1% UDCA. However, in our hamster model, UDCA was inefficient to prevent CDI, despite high levels of UDCA in feces. Patients with PSC-IBD treated with UDCA did not have less CDI than IBD patients