Stefano Alivernini

MicroRNA-155 as a proinflammatory regulator in clinical and experimental arthritis

MicroRNA (miRNA) species (miR) regulate mRNA translation and are implicated as mediators of disease pathology via coordinated regulation of molecular effector pathways. Unraveling miR disease-related activities will facilitate future therapeutic interventions. miR-155 recently has been identified with critical immune regulatory functions. Although detected in articular tissues, the functional role of miR-155 in inflammatory arthritis has not been defined. We report here that miR-155 is up-regulated in synovial membrane and synovial fluid (SF) macrophages from patients with rheumatoid arthritis (RA). The increased expression of miR-155 in SF CD14+ cells was associated with lower expression of the miR-155 target, Src homology 2-containing inositol phosphatase-1 (SHIP-1), an inhibitor of inflammation. Similarly, SHIP-1 expression was decreased in CD68+ cells in the synovial lining layer in RA patients as compared with osteoarthritis patients. Overexpression of miR-155 in PB CD14+ cells led to down-regulation of SHIP-1 and an increase in the production of proinflammatory cytokines. Conversely, inhibition of miR-155 in RA synovial CD14+ cells reduced TNF-α production. Finally, miR-155–deficient mice are resistant to collagen-induced arthritis, with profound suppression of antigen-specific Th17 cell and autoantibody responses and markedly reduced articular inflammation. Our data therefore identify a role of miR-155 in clinical and experimental arthritis and suggest that miR-155 may be an intriguing therapeutic target.

Evaluating antirheumatic treatments using synovial biopsy: a recommendation for standardisation to be used in clinical trials

Inflammation of synovium is one of the hallmarks of rheumatoid arthritis (RA). Analysis of synovial tissue has increased our understanding of RA pathogenesis, aided in identifying potential therapeutic targets and has been used in the response and mechanistic evaluation of antirheumatic treatments. In addition, studies are ongoing, aimed at the identification of diagnostic and prognostic biomarkers in the synovium. This paper outlines the currently used procedures for sampling and processing of synovial tissue, and presents a standardised recommendation to support multicentre translational research.

Interleukin-1β and Interleukin-6 in Arthritis Animal Models: Roles in the Early Phase of Transition from Acute to Chronic Inflammation and Relevance for Human Rheumatoid Arthritis

Tumor necrosis factor-α (TNF-α) is the major target of the therapeutic approach in rheumatoid arthritis. A key issue in the approach to chronic arthritis is the understanding of the crucial molecules driving the transition from the acute phase to the chronic irreversible phase of the disease. In this review we analyzed five experimental arthritis animal models (antigen-induced arthritis, adjuvant-induced arthritis, streptococcal cell wall arthritis, collagen-induced arthritis and SKG) considered as possible scenarios to facilitate interpretation of the biology of human rheumatoid arthritis. The SKG model is strictly dependent on interleukin (IL)-6. In the other models, IL-1β and IL-6, more than TNF-α, appear to be relevant in driving the transition, which suggests that these should be the targets of an early intervention to stop the course toward the chronic form of the disease.

Skin ulcers in systemic sclerosis: Determinants of presence and predictive factors of healing

BACKGROUND Skin ulcers are common vascular complications of systemic sclerosis (SSc). OBJECTIVE The aim of the study was to identify clinical, biologic, and imaging parameters that constitute risk factors for the occurrence and persistence of skin ulcers. METHODS One hundred thirty Italian SSc patients were examined at entry and after 20 months of follow-up. RESULTS The diffuse SSc phenotype with avascular areas on capillaroscopy, thrombophilia, and systemic inflammation as defined by interleukin 6 plasma levels, represented the major risk factors for ulcer development. Infection was associated with a risk of poor or no healing, and cardiopulmonary involvement was a major comorbid factor in patients with ulcers. The presence of infection and avascular areas represented the main determinants for ulcer healing. LIMITATIONS Our data should be confirmed with a longer follow-up period since skin ulcers represent a frequent vascular complication in scleroderma patients. CONCLUSION Aggressive therapies aiming at improving angiogenesis and controlling infection and the course of the disease appear to be crucial to obtain ulcer healing.

PTPN22 1858C>T Polymorphism Distribution in Europe and Association with Rheumatoid Arthritis: Case-Control Study and Meta-Analysis

Objective The PTPN22 rs2476601 polymorphism is associated with rheumatoid arthritis (RA); nonetheless, the association is weaker or absent in some southern European populations. The aim of the study was to evaluate the association between the PTPN22 rs2476601 polymorphism and RA in Italian subjects and to compare our results with those of other European countries, carrying out a meta-analysis of European data. Methods A total of 396 RA cases and 477 controls, all of Italic ancestry, were genotyped for PTPN22 rs2476601 polymorphism. Patients were tested for autoantibodies positivity. The meta-analysis was performed on 23 selected studies. Results The PTPN22 T1858 allele was significantly more frequent in RA patients compared to controls (5.7% vs. 3.7%, p = 0.045). No clear relationship arose with the autoantibodies tested. The 1858T allele frequency in Italian RA patients was lower than the one described in northern European populations and similar to the frequency found in Spain, Turkey, Greece, Tunisia. A clear-cut North-South gradient arose from the analysis. Conclusions The PTPN22 T1858 allele is associated with RA in the Italian population. A North-South gradient of the allele frequency seems to exist in Europe, with a lower prevalence of the mutation in the Mediterranean area.

MicroRNA-155 influences B-cell function through PU.1 in rheumatoid arthritis

MicroRNA-155 (miR-155) is an important regulator of B cells in mice. B cells have a critical role in the pathogenesis of rheumatoid arthritis (RA). Here we show that miR-155 is highly expressed in peripheral blood B cells from RA patients compared with healthy individuals, particularly in the IgD-CD27- memory B-cell population in ACPA+ RA. MiR-155 is highly expressed in RA B cells from patients with synovial tissue containing ectopic germinal centres compared with diffuse synovial tissue. MiR-155 expression is associated reciprocally with lower expression of PU.1 at B-cell level in the synovial compartment. Stimulation of healthy donor B cells with CD40L, anti-IgM, IL-21, CpG, IFN-α, IL-6 or BAFF induces miR-155 and decreases PU.1 expression. Finally, inhibition of endogenous miR-155 in B cells of RA patients restores PU.1 and reduces production of antibodies. Our data suggest that miR-155 is an important regulator of B-cell activation in RA.

ACR70-disease activity score remission achievement from switches between all the available biological agents in rheumatoid arthritis: a systematic review of the literature.

IntroductionThe aim of our analysis was to compare the gaining of a major response (disease activity score [DAS] remission or American College of Rheumatology 70% improvement criteria [ACR70]) by switching between all the available biological therapies in rheumatoid arthritis.MethodsA systematic review was performed including studies, published before December 2008, in which a second biological agent was used and clinical outcomes were evaluated after a first biological failure.ResultsNine articles were included. Switching from etanercept and/or infliximab to adalimumab is effective with an ACR70 response ranging from 5% to 33%. Rituximab may be slightly more effective than switching to a second anti-tumor necrosis factor-alpha (anti-TNFα), reaching an ACR70 or DAS remission response in 12% and 9%, respectively. Clinical trials confirmed the efficacy in switching to abatacept (gain of effect 10.2%). Tocilizumab allows DAS28 (DAS using 28 joint counts) remission in 30.1% but ACR70 only in 12.4% of patients refractory to anti-TNFα.ConclusionsThe efficacy of a second biological agent, irrespective of the mode of action, in reaching an ACR70 or DAS remission after a first biologic is observed from 5% to 15% and from 9% to 15.4%, respectively (except in two studies).

Bronchoalveolar lavage fluid and progression of scleroderma interstitial lung disease

Introduction:  So far no clinical or experimental evidences clearly explain how and which systemic sclerosis (SSc) patients will experience a functional and radiological progression of interstitial lung disease (ILD).

B-cell subsets in the joint compartments of seropositive and seronegative rheumatoid arthritis (RA) and No-RA arthritides express memory markers and ZAP70 and characterize the aggregate pattern irrespectively of the autoantibody status.

The aim of the present study was to determine whether different subsets of B cells characterize synovial fluid (SF) or synovial tissue (ST) of seropositive or seronegative rheumatoid arthritis (RA) with respect to the peripheral blood (PB). PB, SF and ST of 14 autoantibody (AB)-positive (rheumatoid factor (RF)-IgM, RF-IgA, anti-citrullinated peptide (CCP)), 13 negative RA and 13 no-RA chronic arthritides were examined for B-cell subsets (Bm1-Bm5 and IgD-CD27 classifications), zeta-associated protein kinase-70 (ZAP70) expression on B cells and cytokine levels (interleukin (IL)-1β, tumor necrosis factor (TNF)-α, IL-6, IL-8 and monocyte chemotactic protein (MCP)-1). Synovial tissues were classified as aggregate and diffuse patterns. No differences were found in B-cell percentages or in subsets in PB and SF between AB+ and AB− RA and no-RA. In both AB+ and AB− RA (and no-RA), the percentage of CD19+/ZAP70+ was higher in SF than in PB (AB+: P= 0.03; AB−: P = 0.01; no-RA: P = 0.01). Moreover, SF of both AB+ and AB− RA (and no-RA) patients was characterized by a higher percentage of IgD-CD27+ and IgD-CD27− B cells and lower percentage of IgD+CD27− (P < 0.05) B cells compared to PB. In SF, ZAP70 positivity is more represented in B cell CD27+/IgD−/CD38−. The aggregate synovitis pattern was characterized by higher percentages of Bm5 cells in SF compared with the diffuse pattern (P = 0.05). These data suggest that no difference exists between AB+ and AB− in B-cell subset compartmentalization. CD27+/IgD−/ZAP70+ memory B cells accumulate preferentially in the joints of RA, suggesting a dynamic maturation of the B cells in this compartment.

MicroRNA-34a dependent regulation of AXL controls the activation of dendritic cells in inflammatory arthritis

Current treatments for rheumatoid arthritis (RA) do not reverse underlying aberrant immune function. A genetic predisposition to RA, such as HLA-DR4 positivity, indicates that dendritic cells (DC) are of crucial importance to pathogenesis by activating auto-reactive lymphocytes. Here we show that microRNA-34a provides homoeostatic control of CD1c+ DC activation via regulation of tyrosine kinase receptor AXL, an important inhibitory DC auto-regulator. This pathway is aberrant in CD1c+ DCs from patients with RA, with upregulation of miR-34a and lower levels of AXL compared to DC from healthy donors. Production of pro-inflammatory cytokines is reduced by ex vivo gene-silencing of miR-34a. miR-34a-deficient mice are resistant to collagen-induced arthritis and interaction of DCs and T cells from these mice are reduced and do not support the development of Th17 cells in vivo. Our findings therefore show that miR-34a is an epigenetic regulator of DC function that may contribute to RA.