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Aim. The aim of this study was to investigate whether cytokines associated with tumour necrosis factor- (TNF-) α and interleukin- (IL-) 6 signalling could predict rheumatoid arthritis (RA) clinical remission (CR) with Janus kinase inhibitor (JAKinib) treatment using the Simplified Disease Activity Index (SDAI). Methods. Eighty-nine patients with RA treated with JAKinibs were enrolled, and their clinical data were collected retrospectively. CR was defined as an SDAI ≤ 3.3 after 6 months of treatment with JAKinib. The serum samples of 89 patients were analysed for IL-6, soluble IL-6 receptor (sIL-6R), soluble gp130 (spg130), and soluble TNF receptor- (sTNFR-) I and sTNFR-II titres. Results. There were no significant differences in the baseline clinical parameters between the CR and non-CR groups. Serum levels of IL-6, sIL-6R, and sgp130 were not significantly different; whereas, the serum sTNFR-I and sTNFR-II levels were significantly lower in the CR group. Univariate and multivariate logistic regression analysis showed that the baseline log sTNFR II values (OR: 0.002; p = 0.034) were predictors of CR. Conclusions. Patients with RA can be stratified prior to JAKinib administration using serum sTNFR-I and sTNFR-II levels but not serum IL-6 axis cytokine levels (IL-6, sIL-6R, and sgp130). [ABSTRACT FROM AUTHOR]

Endogenous DNA is released into the bloodstream as cell-free DNA (cfDNA) following cell death and is associated with various pathological conditions. However, their association with therapeutic drugs against rheumatoid arthritis (RA) remains unknown. Therefore, we investigated the significance of cfDNA in RA treated with tocilizumab and tumour necrosis factor inhibitor (TNF-I). Biological DMARDs (bDMARDs), including tocilizumab and TNF-I, were administered to 77 and 59 RA patients, respectively. Plasma cfDNA levels were measured at weeks 0, 4, and 12 by quantitative polymerase chain reaction. Disease activity was evaluated at the same time point using DAS28ESR. cfDNA levels from RA synovial cells treated with tocilizumab or etanercept for 24 h were measured. Human toll-like receptor 9 (hTLR9)-expressing HEK293 cells, which release secreted embryonic alkaline phosphatase (SEAP) upon NF-κB activation, were stimulated by cfDNA from RA patients, and subsequently, SEAP levels were determined. NF-κB translocation was evaluated by immunofluorescence staining with or without tocilizumab. The DAS28ESR significantly improved in both bDMARD groups at week 12. However, plasma cfDNA levels significantly decreased in the tocilizumab group at week 12 compared to that in week 0. cfDNA levels correlated with DAS28ESR in biological treatment-naïve patients administered tocilizumab. cfDNA levels in synovial cells were significantly suppressed by tocilizumab treatment and unaltered with etanercept. HEK293 cells released SEAP upon cfDNA stimulation, and the observed NF-κB nuclear translocation was suppressed by tocilizumab. Tocilizumab suppressed inflammation via the TLR9 pathway by decreasing cfDNA levels. Regulation of cfDNA may be a therapeutic target for RA. Cell-free DNA (cfDNA) from patients with rheumatoid arthritis (RA) activates NF-κB via the toll-like receptor 9 (TLR-9) signalling pathway in vitro. Tocilizumab, but not tumour necrosis factor inhibitors, decreases cfDNA levels in RA patients and RA-associated fibroblast-like synoviocytes. Tocilizumab degrades cfDNA at clinically relevant concentrations, suggesting tocilizumab likely controls inflammation in RA by suppressing TLR-9-dependent NF-κB signalling. [ABSTRACT FROM AUTHOR]

Aim To evaluate the correlation between circulating cell-free DNA (ccfDNA) in plasma and clinical disease activities in patients with rheumatoid arthritis (RA). Method The study group included 30 patients with RA who started biological disease-modifying anti-rheumatic drugs (DMARDs) therapy. The concentration of ccfDNA in plasma was measured by quantitative real-time polymerase chain reaction at baseline to 24 weeks in every 4-week period from 30 patients and 21 healthy individuals. We also evaluated the correlation between ccfDNA and the clinical activity or the therapeutic response for biological DMARDs, using the simplified disease activity index (SDAI), Disease Activity Score of 28 joints (erythrocyte sedimentation rate) and the European League Against Rheumatism (EULAR) response criteria. Synovial fluid samples of knee joints were collected from 13 patients with RA and 12 with osteoarthritis (OA) to measure ccfDNA. Result The concentration of ccfDNA in RA patients at baseline was higher than healthy controls ( P = 0.016). After introducing biological DMARDs, ccfDNA was increased until 8 weeks from the baseline, and decreased after 12 weeks. The average of SDAI was improved in all patients enrolled. At 12 weeks after treatment, 15 patients were good responders to the EULAR response criteria, nine showed moderate response and six showed no response. ccfDNA in good responders was increased until 8 weeks, while those of moderate or no response were not ( P = 0.042). In joint fluid of RA patients, ccfDNA was remarkably increased as compared to those from OA ( P = 0.00011). Conclusion After introducing biological DMARDs, increase of ccfDNA at 8 weeks was associated with improvement of disease activities. Compared with biomarkers reported, ccfDNA is able to predict the early therapeutic effects of biological DMARDs in RA patients. [ABSTRACT FROM AUTHOR]

Endogenous DNA derived from the nuclei or mitochondria is released into the bloodstream following cell damage or death. Extracellular DNA, called cell-free DNA (cfDNA), is associated with various pathological conditions. Recently, multiple aspects of cfDNA have been assessed, including cfDNA levels, integrity, methylation, and mutations. Rheumatoid arthritis (RA) is the most common form of autoimmune arthritis, and treatment of RA has highly varied outcomes. cfDNA in patients with RA is elevated in peripheral blood and synovial fluid and is associated with disease activity. Profiling of cfDNA in patients with RA may then be utilized in various aspects of clinical practice, such as the prediction of prognosis and treatment responses; monitoring disease state; and as a diagnostic marker. In this review, we discuss cfDNA in patients with RA, particularly the sources of cfDNA and the correlation of cfDNA with RA pathogenesis. We also highlight the potential of analyzing cfDNA profiles to guide individualized treatment approaches for RA. [ABSTRACT FROM AUTHOR]

Tumor necrosis factor (TNF)-α is responsible for expressions of several clock genes and affects joint symptoms of rheumatoid arthritis (RA) with diurnal fluctuation. We tried to determine the mechanism involved in over-expression of Bmal1 , induced by TNF-α, in primary cultured rheumatoid synovial cells. Cells were incubated with intra-cellular Ca 2+ chelator BAPTA-AM, calcineurin inhibitor FK506 and p300/CBP (CREB binding protein) inhibitor C646, respectively, or transfected with p300 and CBP small interfering RNA (siRNA) before stimulation with TNF-α. Oscillation phase and amplitude of Bmal1 , transcriptional activator Rorα , transcriptional repressor Rev-erbα , and histone acetyltransferases ( p300 and Cbp ) were evaluated by quantitative real-time PCR. As results, TNF-α did not influence the oscillation phase of Rev-erbα , while enhanced those of Rorα , resulting in over-expression of Bmal1 . When Ca 2+ influx was inhibited by BAPTA-AM, TNF-α-mediated up-regulation of Rorα was cancelled, however, that of Bmal1 was still apparent. When we further explored another pathway between TNF-α and Bmal1 , TNF-α suppressed the expression of Rev-erbα in the absence of Ca 2+ influx, as well as those of p300 and Cbp genes. Finally, actions of TNF-α, in increasing Bmal1 / Rorα and decreasing Rev-erbα, were cancelled by C646 treatment or silencing of both p300 and Cbp . In conclusion, we determined a novel role of TNF-α in inducing Bmal1 via dual calcium dependent pathways; Rorα was up-regulated in the presence of Ca 2+ influx and Rev-erbα was down-regulated in the absence of that. Results proposed that inhibition of p300/CBP could be new therapeutic targets for RA. [ABSTRACT FROM AUTHOR]