Laura Papon

TRIM22 E3 ubiquitin ligase activity is required to mediate antiviral activity against encephalomyocarditis virus.

The interferon (IFN) system is a major effector of the innate immunity that allows time for the subsequent establishment of an adaptive immune response against a wide-range of pathogens. Their diverse biological actions are thought to be mediated by the products of specific but usually overlapping sets of cellular genes induced in the target cells. Ubiquitin ligase members of the tripartite motif (TRIM) protein family have emerged as IFN-induced proteins involved in both innate and adaptive immunity. In this report, we provide evidence that TRIM22 is a functional E3 ubiquitin ligase that is also ubiquitinated itself. We demonstrate that TRIM22 expression leads to a viral protection of HeLa cells against encephalomyocarditis virus infections. This effect is dependent upon its E3 ubiquitinating activity, since no antiviral effect was observed in cells expressing a TRIM22-deletion mutant defective in ubiquitinating activity. Consistent with this, TRIM22 interacts with the viral 3C protease (3C(PRO)) and mediates its ubiquitination. Altogether, our findings demonstrate that TRIM22 E3 ubiquitin ligase activity represents a new antiviral pathway induced by IFN against picornaviruses.

The viral RNA recognition sensor RIG-I is degraded during encephalomyocarditis virus (EMCV) infection.

RNA helicase-like receptors MDA-5 but not RIG-I has been shown to be essential for triggering innate immune responses against picornaviruses. However, virus-host co-evolution has selected for viruses capable of replicating despite host cells antiviral defences. In this report, we demonstrate that RIG-I is degraded during encephalomyocarditis virus (EMCV) infection. This effect is mediated by both the viral-encoded 3C protease and caspase proteinase. In addition, we show that RIG-I overexpression confers IFN-beta promoter activation during EMCV infection, in MDA-5 knockout (MDA-5(-/-)) mouse embryo fibroblasts. This induction is followed by a strong inhibition reflecting the ability of EMCV to disrupt RIG-I signalling. Taken together, our data strongly suggest that during evolution RIG-I has been involved for triggering innate immune response to picornavirus infections.

Tubulin glycylases are required for primary cilia, control of cell proliferation and tumor development in colon

TTLL3 and TTLL8 are tubulin glycine ligases catalyzing posttranslational glycylation of microtubules. We show here for the first time that these enzymes are required for robust formation of primary cilia. We further discover the existence of primary cilia in colon and demonstrate that TTLL3 is the only glycylase in this organ. As a consequence, colon epithelium shows a reduced number of primary cilia accompanied by an increased rate of cell division in TTLL3‐knockout mice. Strikingly, higher proliferation is compensated by faster tissue turnover in normal colon. In a mouse model for tumorigenesis, lack of TTLL3 strongly promotes tumor development. We further demonstrate that decreased levels of TTLL3 expression are linked to the development of human colorectal carcinomas. Thus, we have uncovered a novel role for tubulin glycylation in primary cilia maintenance, which controls cell proliferation of colon epithelial cells and plays an essential role in colon cancer development.

The TNF family member APRIL dampens collagen-induced arthritis

Background The tumour necrosis factor (TNF)-family members B cell activating factor (BAFF) and A PRoliferation-Inducing Ligand (APRIL) play important roles in B cell biology, and share binding to B cell maturation antigen and transmembrane activator and cyclophilin ligand interactor, both receptors of the TNF-family. However, while it is reported that BAFF can break B cell tolerance, the role of APRIL in autoimmunity remains elusive. Objective To evaluate the role of APRIL on collagen-induced arthritis (CIA). Methods CIA was induced in APRIL-transgenic (Tg) DBA/1 mice and littermates. Disease progression was evaluated by clinical and histological signs of arthritis. In another experimental setting mice were exposed to the collagen antibody-induced arthritis. In addition, we tested T cell dependent humoral responses in APRIL-Tg mice. Results We found that APRIL-Tg displayed a strongly reduced incidence and severity of CIA compared with littermates, with decreases in collagen-specific autoantibody titres, immune complex deposition and downstream mast cell activation in joints. Notably, ectopic APRIL-expression was also found to negatively regulate T cell dependent humoral responses. The lower autoantibody production in APRIL-Tg mice during CIA appears to be crucial, as arthritis induced by administration of anti-collagen antibodies developed similar in APRIL-Tg and control mice, thus demonstrating that the downstream effector pathways induced by anti-collagen antibodies remain intact in APRIL-Tg mice. This protective effect was specifically mediated by APRIL, as adenoviral delivery of APRIL decreased CIA in a therapeutic setting. Conclusions Collectively, our data identify APRIL as a negative regulator of CIA by regulating autoantibody production. These findings are of important clinical relevance, as the therapeutic potential of transmembrane activator and cyclophilin ligand interactor-Fc (atacicept) is presently evaluated in clinical trials.

Osteoprotegerin and tumor necrosis factor-related apoptosis-inducing ligand as prognostic factors in rheumatoid arthritis: results from the ESPOIR cohort.

IntroductionWe previously reported that low ratio of osteoprotegerin (OPG) to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) was associated with Disease Activity Score in 28 joints (DAS28) remission at 6 months in patients with early rheumatoid arthritis (RA). Here, we aimed to evaluate the value of baseline OPG/TRAIL ratio in predicting clinical and radiological outcomes in patients with early RA in the ESPOIR cohort.MethodsOPG and TRAIL serum concentrations were assessed in the ESPOIR cohort patients. Patients with definite RA were included in this study. Patients were excluded if they had high erosion score at baseline (>90th percentile) or received biological therapy during the first 2 years of follow-up. Data were analyzed by univariate analysis and multivariate logistic regression to predict 1-year DAS28 remission and 2-year radiographic disease progression.ResultsOn univariate analysis of 399 patients, OPG/TRAIL ratio at baseline was significantly lower in patients with than without remission at 1 year (p = 0.015). On multivariate logistic regression including age, gender, body mass index and DAS28, low OPG/TRAIL ratio was independently associated with remission at 1 year (odds ratio 1.68 [95 % confidence interval 1.01–2.79]). On univariate analysis, high OPG/TRAIL ratio at baseline was associated with rapid progression of erosion at 2 years (p = 0.041), and on multivariate logistic regression including age, anti-citrullinated protein antibody positivity and C-reactive protein level, OPG/TRAIL ratio independently predicted rapid progression of erosion at 2 years.ConclusionsOPG/TRAIL ratio at baseline was an independent predictor of 1-year remission and 2-year rapid progression of erosion for patients with early rheumatoid arthritis. Thus, OPG/TRAIL ratio could be included in matrix prediction scores to predict rapid radiographic progression. Further confirmation in an independent cohort is warranted.

Distinct Effects of Soluble and Membrane-Bound Fas Ligand on Fibroblast-like Synoviocytes From Rheumatoid Arthritis Patients

Injection of agonistic anti‐Fas antibody has been shown to decrease disease symptoms in mouse models of arthritis. Additionally, membrane‐bound FasL (mFasL) has been shown to induce cell death in fibroblast‐like synoviocytes (FLS) from rheumatoid arthritis (RA) patients. However, levels of soluble FasL (sFasL) are increased in the joints of RA patients and have been associated with disease severity, indicating that mFasL and sFasL play opposing roles in RA. The purpose of this study was to analyze the effects of FasL on RA FLS responses.

The Anti-Hiv Candidate Abx464 Dampens Intestinal Inflammation by Triggering Il-22 Production in Activated Macrophages

The progression of human immunodeficiency virus (HIV) is associated with mucosal damage in the gastrointestinal (GI) tract. This damage enables bacterial translocation from the gut and leads to subsequent inflammation. Dextran sulfate sodium (DSS-exposure) is an established animal model for experimental colitis that was recently shown to recapitulate the link between GI-tract damage and pathogenic features of SIV infection. The current study tested the protective properties of ABX464, a first-in-class anti-HIV drug candidate currently in phase II clinical trials. ABX464 treatment strongly attenuated DSS-induced colitis in mice and produced a long-term protection against prolonged DSS-exposure after drug cessation. Consistently, ABX464 reduced the colonic production of the inflammatory cytokines IL-6 and TNFα as well as that of the chemoattractant MCP-1. However, RNA profiling analysis revealed the capacity of ABX464 to induce the expression of IL-22, a cytokine involved in colitis tissue repair, both in DSS-treated mice and in LPS-stimulated bone marrow-derived macrophages. Importantly, anti-IL-22 antibodies significantly reduced the protective effect of ABX464 on colitis in DSS-treated mice. Because reduced IL-22 production in the gut mucosa is an established factor of HIV and DSS-induced immunopathogenesis, our data suggest that the anti-inflammatory properties of ABX464 warrant exploration in both HIV and inflammatory ulcerative colitis (UC) disease.

Circulating APRIL levels are correlated with advanced disease and prognosis in rectal cancer patients

We have previously shown that the tumor necrosis factor family member a proliferation-inducing ligand (APRIL) enhances intestinal tumor growth in various preclinical tumor models. Here, we have investigated whether APRIL serum levels at time of surgery predict survival in a large cohort of colorectal cancer (CRC) patients. We measured circulating APRIL levels in a cohort of CRC patients (n=432) using a novel validated monoclonal APRIL antibody (hAPRIL.133) in an enzyme-linked immunosorbent assay (ELISA) setup. APRIL levels were correlated with clinicopathological features and outcome. Overall survival was examined with Kaplan–Meier survival analysis, and Cox proportional hazards ratios were calculated. We observed that circulating APRIL levels were normally distributed among CRC patients. High APRIL expression correlated significantly with poor outcome measures, such as higher stage at presentation and development of lymphatic and distant metastases. Within the group of rectal cancer patients, higher circulating APRIL levels at time of surgery were correlated with poor survival (log-rank analysis P-value 0.008). Univariate Cox regression analysis for overall survival in rectal cancer patients showed that patients with elevated circulating APRIL levels had an increased risk of poor outcome (hazard ratio (HR) 1.79; 95% confidence interval (CI) 1.16–2.76; P-value 0.009). Multivariate analysis in rectal cancer patients showed that APRIL as a prognostic factor was dependent on stage of disease (HR 1.25; 95% CI 0.79–1.99; P-value 0.340), which was related to the fact that stage IV rectal cancer patients had significantly higher levels of APRIL. Our results revealed that APRIL serum levels at time of surgery were associated with features of advanced disease and prognosis in rectal cancer patients, which strengthens the previously reported preclinical observation of increased APRIL levels correlating with disease progression.

RNA sequencing analysis of activated macrophages treated with the anti-HIV ABX464 in intestinal inflammation

RNA-Seq enables the generation of extensive transcriptome information providing the capability to characterize transcripts (including alternative isoforms and polymorphism), to quantify expression and to identify differential regulation in a single experiment. To reveal the capacity of new anti-HIV ABX464 candidate in modulating the expression of genes, datasets were generated and validated using RNA-seq approach. This comprehensive dataset will be useful to deepen the comprehensive understanding of the progression of human immunodeficiency virus (HIV) associated with mucosal damage in the gastrointestinal (GI) tract and subsequent inflammation, providing an opportunity to generate new therapies, diagnoses, and preventive strategies.

SAT0002 Baseline Serum OPG but not Trail Predicts Remission in Early Arthritis: Results from the French Espoir Cohort

Background TNF-Related Apoptosis Inducing Ligand (TRAIL) is a member of the TNF familly. Osteoprotegerin (OPG) is a soluble receptor of TRAIL that also inhibits Receptor activator of nuclear factor kappa-B ligand (RANKL). We previously reported that, in a cohort of early arthritis(< 2 years), a high TRAIL/OPG ratio at baseline was associated with remission (DAS28<2.6) at 6 months. This result suggested that the TRAIL/OPG ratio could be used as a predictive factor for remission in early arthritis. Objectives The aim of this study was to confirm these results in a larger cohort. We measure TRAIL and OPG in sera from patients included in the French cohort ESPOIR. We correlated these values with disease activity and radiographic progression. We also aimed to compare TRAIL and OPG between patients with arthritis responding to ACR/EULAR 2010 criteria (RA) and the undifferentiated arthritis (UA). Methods To be included in the French cohort ESPOIR, patients should have an early arthritis (< 6 months). Patients were assessed for clinical and biological parameters at baseline, 6, 12, and 24 months and for radiographic progression at baseline, 12 and 24 months (Sharp’s score). TRAIL and OPG in serum were measured at inclusion (M0) and at 12 month follow-up. Values were normalized using logOPG and logTRAIL. Cytokine levels between groups were compared using the unpaired t-test with significance set to p <0.05. Correlations were performed using Pearson tests. Changes between baseline and 12 months were assessed using paired t-test. Adjustment was performed using ANCOVA on normalized values. Results TRAIL, OPG and TRAIL/OPG at baseline were not different between RA patients (n = 641) and UA patients (n = 53). Among RA patients, OPG was significantly correlated at baseline with DAS28(r=0.14; p<0.001), ESR (r=0.17; p<0.001) and CRP (r=0.13; p<0.001). At inclusion, TRAIL/OPG ratio was inversely correlated with DAS28(r=-0.11; p=0.006), ESR (r=-0.15; p<0.001) and CRP (r=-0.16; p<0.001). TRAIL was only inversely correlated with CRP (r=-0.10; p=0.02). For RA patients followed at 12 months (n = 571), we oberved a significant decrease of DAS28 (mean±SD from 5.3 [4.6-6.2] to 3.1 [2.2-4.1]; p<0.001) and in TRAIL (-249±596 pg/ml; p<0.001) and OPG concentrations (-128±403 pg/ml; p<0.001). TRAIL/OPG ratio remained stable. Patients in EULAR remission at 12 months (n = 206) had a significantly lower baseline concentration of OPG than patients who were not in remission (n = 349) (921±418 vs 1014±383 pg/ml, respectively, p=0.001). Patients in remission at 12 months (n = 206) also had a significantly higher baseline TRAIL/OPG ratio (1.40±1.02 vs 1.18±0.60 pg/ml, p=0.04). After adjustment for DAS28, CRP and age at inclusion, OPG at baseline remained significantly lower in patients in remission at 12 months (p=0.007) whereas it was no significant anymore for the ratio TRAIL/OPG (p=0.13). Conclusions Concentrations of TRAIL and OPG could not help in distinguish undifferentiated arthritis and RA. OPG was correlated with ESR, CRP and DAS28 and TRAIL inversely correlated with CRO. OPG and TRAIL significantly decreased between M0 and M12. This study does not confirm the predictive value of the ratio TRAIL/OPG. However, a low OPG value at baseline was associated with EULAR remission at 12 months. References Acknowledgements We also wish to thank The French Society of Rheumatology which supported ESPOIR cohort study and our work. We also wish to thank N. Rincheval who did expert monitoring and data management, V. Dechauvelle and C. Lukas for expert x-ray reading and all the investigators who recruited and followed the patients Disclosure of Interest None Declared