BACKGROUND:Although methotrexate (MTX) is the consensual first-line disease-modifying antirheumatic drug (DMARD) for rheumatoid arthritis (RA), substantial heterogeneity remains with its prescription and dosage, which are often not optimal. OBJECTIVE:To evaluate the symptomatic and structural impact of optimal MTX dose in patients with early RA in daily clinical practice over 2 years. METHODS:Patients included in the early arthritis ESPOIR cohort who fulfilled the ACR-EULAR (American College of Rheumatology/European League against Rheumatism) criteria for RA and received MTX as a first DMARD were assessed. Optimal MTX dose was defined as ≥10 mg/week during the first 3 months, with escalation to ≥20 mg/week or 0.3 mg/kg/week at 6 months without Disease Activity Score in 28 joints remission. Symptomatic and structural efficacy with and without optimal MTX dose was assessed by generalised logistic regression with adjustment for appropriate variables. RESULTS:Within the first year of follow-up, 314 patients (53%) with RA received MTX as a first DMARD (mean dose 12.2±3.8 mg/week). Only 26.4% (n=76) had optimal MTX dose. After adjustment, optimal versus non-optimal MTX dose was more efficient in achieving ACR-EULAR remission at 1 year (OR 4.28 (95% CI 1.86 to 9.86)) and normal functioning (Health Assessment Questionnaire ≤0.5; OR at 1 year 4.36 (95% CI 2.03 to 9.39)), with no effect on radiological progression. Results were similar during the second year. CONCLUSION:Optimal MTX dose is more efficacious than non-optimal dose for remission and function in early arthritis in daily practice, with no impact on radiological progression over 2 years.

OBJECTIVES:Methotrexate (MTX) is the anchor drug for treatment of rheumatoid arthritis (RA), but the mechanism of its anti-inflammatory action is not fully understood. In RA, macrophages display a proinflammatory polarisation profile that resembles granulocyte-macrophage colony-stimulating factor (GM-CSF)-differentiated macrophages and the response to MTX is only observed in thymidylate synthase GM-CSF-dependent macrophages. To determine the molecular basis for the MTX anti-inflammatory action, we explored toll-like receptor (TLR), RA synovial fluid (RASF) and tumour necrosis factor receptor (TNFR)-initiated signalling in MTX-exposed GM-CSF-primed macrophages. METHODS:Intracellular responses to TLR ligands, TNFα or RASF stimulation in long-term low-dose MTX-exposed human macrophages were determined through quantitative real-time PCR, western blot, ELISA and siRNA-mediated knockdown approaches. The role of MTX in vivo was assessed in patients with arthritis under MTX monotherapy and in a murine sepsis model. RESULTS:MTX conditioned macrophages towards a tolerant state, diminishing interleukin (IL)-6 and IL-1β production in LPS, LTA, TNFα or RASF-challenged macrophages. MTX attenuated LPS-induced MAPK and NF-κB activation, and toll/IL-1R domain-containing adaptor inducing IFN-beta (TRIF1)-dependent signalling. Conversely, MTX increased the expression of the NF-κB suppressor A20 (), itself a RA-susceptibility gene. Mechanistically, MTX-induced macrophage tolerance was dependent on A20, as siRNA-mediated knockdown of A20 reversed the MTX-induced reduction of IL-6 expression. In vivo, expression was significantly higher in peripheral blood cells of MTX-responsive individuals from a cohort of patients with arthritis under MTX monotherapy, whereas MTX-treated mice exhibited reduced inflammatory responses to LPS. CONCLUSIONS:MTX impairs macrophage proinflammatory responses through upregulation of A20 expression. The A20-mediated MTX-induced innate tolerance might limit inflammation in the RA synovial context, and positions A20 as a potential MTX-response biomarker.

The progressive debilitating nature of rheumatoid arthritis (RA) combined with its unknown etiology and initial similarity to other inflammatory diseases makes early diagnosis a significant challenge. Early recognition and treatment of RA is essential for achieving effective therapeutic outcome. NIR-II photoacoustic (PA) molecular imaging (PMI) is emerging as a promising new strategy for effective diagnosis and treatment guidance of RA, owing to its high sensitivity and specificity at large penetration depth. Herein, an antirheumatic targeted drug tocilizumab (TCZ) is conjugated to polymer nanoparticles (PNPs) to develop the first NIR-II theranostic nanoplatform, named TCZ-PNPs, for PA-imaging-guided therapy of RA. The TCZ-PNPs are demonstrated to have strong NIR-II extinction coefficient, high photostability and excellent biocompatibility. NIR-II PMI results reveal the excellent targeting abilities of TCZ-PNPs for the effective noninvasive diagnosis of RA joint tissue with a high signal-to noise ratio (SNR) of 35.8 dB in 3D PA tomography images. Remarkably, one-month treatment and PA monitoring using TCZ-PNPs shows RA is significantly suppressed. In addition, the therapeutic evaluation of RA mice by NIR-II PMI is shown to be consistent with clinical micro-CT and histological analysis. The TCZ-PNPs-assisted NIR-II PMI provides a new strategy for RA theranostics, therapeutic monitoring and the beyond.

Poor O supply to the infiltrated immune cells in the joint synovium of rheumatoid arthritis (RA) up-regulates hypoxia-inducible factor (HIF-1α) expression and induces reactive oxygen species (ROS) generation, both of which exacerbate synovial inflammation. Synovial inflammation in RA can be resolved by eliminating pro-inflammatory M1 macrophages and inducing anti-inflammatory M2 macrophages. Because hypoxia and ROS in the RA synovium play a crucial role in the induction of M1 macrophages and reduction of M2 macrophages, herein, we develop manganese ferrite and ceria nanoparticle-anchored mesoporous silica nanoparticles (MFC-MSNs) that can synergistically scavenge ROS and produce O for reducing M1 macrophage levels and inducing M2 macrophages for RA treatment. MFC-MSNs exhibit a synergistic effect on O generation and ROS scavenging that is attributed to the complementary reaction of ceria nanoparticles (NPs) that can scavenge intermediate hydroxyl radicals generated by manganese ferrite NPs in the process of O generation during the Fenton reaction, leading to the efficient polarization of M1 to M2 macrophages both in vitro and in vivo. Intra-articular administration of MFC-MSNs to rat RA models alleviated hypoxia, inflammation, and pathological features in the joint. Furthermore, MSNs were used as a drug-delivery vehicle, releasing the anti-rheumatic drug methotrexate in a sustained manner to augment the therapeutic effect of MFC-MSNs. This study highlights the therapeutic potential of MFC-MSNs that simultaneously generate O and scavenge ROS, subsequently driving inflammatory macrophages to the anti-inflammatory subtype for RA treatment.

BACKGROUND:In rheumatoid arthritis (RA) trials, inclusion of patients on background treatment with glucocorticoids (GCs) might impact efficacy and safety outcomes. OBJECTIVES:To determine if inclusion of patients on background GC use influenced efficacy and safety outcomes of RA randomised clinical trials on initiation of tocilizumab (TCZ) or adalimumab (ADA) or methotrexate (MTX) monotherapy. METHODS:Data of four double-blind RA randomised controlled trials (AMBITION, ACT-RAY, ADACTA and FUNCTION) with in total four TCZ, one ADA and two MTX monotherapy arms were analysed. Analyses of covariance of changes from baseline to week 24 in efficacy endpoints and radiographic progression up to week 104 were performed, correcting for relevant covariates. Incidence rates of serious adverse events (SAEs) were assessed. RESULTS:No statistically significant differences were found in efficacy parameters between background GC users and non-GC users, except for less radiographic progression associated with GC usage in one MTX arm. SAE rates were not statistically significantly different between GC users and non-GC users in the treatment arms. CONCLUSION:No effect of including patients on background GC treatment on efficacy and safety trial outcomes was found, with the exception of reduced radiological joint damage in one MTX arm.

OBJECTIVES:Tristetraprolin (TTP), a negative regulator of many pro-inflammatory genes, is strongly expressed in rheumatoid synovial cells. The mitogen-activated protein kinase (MAPK) p38 pathway mediates the inactivation of TTP via phosphorylation of two serine residues. We wished to test the hypothesis that these phosphorylations contribute to the development of inflammatory arthritis, and that, conversely, joint inflammation may be inhibited by promoting the dephosphorylation and activation of TTP. METHODS:The expression of TTP and its relationship with MAPK p38 activity were examined in non-inflamed and rheumatoid arthritis (RA) synovial tissue. Experimental arthritis was induced in a genetically modified mouse strain, in which endogenous TTP cannot be phosphorylated and inactivated. In vitro and in vivo experiments were performed to test anti-inflammatory effects of compounds that activate the protein phosphatase 2A (PP2A) and promote dephosphorylation of TTP. RESULTS:TTP expression was significantly higher in RA than non-inflamed synovium, detected in macrophages, vascular endothelial cells and some fibroblasts and co-localised with MAPK p38 activation. Substitution of TTP phosphorylation sites conferred dramatic protection against inflammatory arthritis in mice. Two distinct PP2A agonists also reduced inflammation and prevented bone erosion. In vitro anti-inflammatory effects of PP2A agonism were mediated by TTP activation. CONCLUSIONS:The phosphorylation state of TTP is a critical determinant of inflammatory responses, and a tractable target for novel anti-inflammatory treatments.

Patients with rheumatoid arthritis (RA) receive highly targeted biologic therapies without previous knowledge of target expression levels in the diseased tissue. Approximately 40% of patients do not respond to individual biologic therapies and 5-20% are refractory to all. In a biopsy-based, precision-medicine, randomized clinical trial in RA (R4RA; n = 164), patients with low/absent synovial B cell molecular signature had a lower response to rituximab (anti-CD20 monoclonal antibody) compared with that to tocilizumab (anti-IL6R monoclonal antibody) although the exact mechanisms of response/nonresponse remain to be established. Here, in-depth histological/molecular analyses of R4RA synovial biopsies identify humoral immune response gene signatures associated with response to rituximab and tocilizumab, and a stromal/fibroblast signature in patients refractory to all medications. Post-treatment changes in synovial gene expression and cell infiltration highlighted divergent effects of rituximab and tocilizumab relating to differing response/nonresponse mechanisms. Using ten-by-tenfold nested cross-validation, we developed machine learning algorithms predictive of response to rituximab (area under the curve (AUC) = 0.74), tocilizumab (AUC = 0.68) and, notably, multidrug resistance (AUC = 0.69). This study supports the notion that disease endotypes, driven by diverse molecular pathology pathways in the diseased tissue, determine diverse clinical and treatment-response phenotypes. It also highlights the importance of integration of molecular pathology signatures into clinical algorithms to optimize the future use of existing medications and inform the development of new drugs for refractory patients.

BACKGROUND:JAK-inhibitors (JAKi), recently approved in rheumatoid arthritis (RA), have changed the landscape of treatment choices. We aimed to compare the effectiveness of four current second-line therapies of RA with different modes of action, since JAKi approval, in an international collaboration of 19 registers. METHODS:In this observational cohort study, patients initiating tumour necrosis factor inhibitors (TNFi), interleukin-6 inhibitors (IL-6i), abatacept (ABA) or JAKi were included. We compared the effectiveness of these treatments in terms of drug discontinuation and Clinical Disease Activity Index (CDAI) response rates at 1 year. Analyses were adjusted for patient, disease and treatment characteristics, including lines of therapy and accounted for competing risk. RESULTS:We included 31 846 treatment courses: 17 522 TNFi, 2775 ABA, 3863 IL-6i and 7686 JAKi. Adjusted analyses of overall discontinuation were similar across all treatments. The main single reason of stopping treatment was ineffectiveness. Compared with TNFi, JAKi were less often discontinued for ineffectiveness (adjusted HR (aHR) 0.75, 95% CI 0.67 to 0.83), as was IL-6i (aHR 0.76, 95% CI 0.67 to 0.85) and more often for adverse events (aHR 1.16, 95% CI 1.03 to 1.33). Adjusted CDAI response rates at 1 year were similar between TNFi, JAKi and IL-6i and slightly lower for ABA. CONCLUSION:The adjusted overall drug discontinuation and 1 year response rates of JAKi and IL-6i were similar to those observed with TNFi. Compared with TNFi, JAKi were more often discontinued for adverse events and less for ineffectiveness, as were IL-6i.

The differentiation of IL-10-producing regulatory B cells (Bregs) in response to gut-microbiota-derived signals supports the maintenance of tolerance. However, whether microbiota-derived metabolites can modulate Breg suppressive function remains unknown. Here, we demonstrate that rheumatoid arthritis (RA) patients and arthritic mice have a reduction in microbial-derived short-chain fatty acids (SCFAs) compared to healthy controls and that in mice, supplementation with the SCFA butyrate reduces arthritis severity. Butyrate supplementation suppresses arthritis in a Breg-dependent manner by increasing the level of the serotonin-derived metabolite 5-Hydroxyindole-3-acetic acid (5-HIAA), which activates the aryl-hydrocarbon receptor (AhR), a newly discovered transcriptional marker for Breg function. Thus, butyrate supplementation via AhR activation controls a molecular program that supports Breg function while inhibiting germinal center (GC) B cell and plasmablast differentiation. Our study demonstrates that butyrate supplementation may serve as a viable therapy for the amelioration of systemic autoimmune disorders.