Iguratimod inhibits protein citrullination and inflammation by downregulating NBCe2 in patients with rheumatoid arthritis.

BACKGROUND: Bicarbonate has recently been identified as a crucial factor affecting peptidylarginine deiminase (PAD) activity; however, the mechanism underlying its role in rheumatoid arthritis (RA) remains unclear. Iguratimod (IGU), a small-molecule disease-modifying anti-rheumatic drug, requires further investigation. This study aimed to explore the mechanism by which bicarbonate affects citrullination and inflammation in RA and identify new targets for IGU. METHODS: We enrolled 20 patients with RA in the study. Sodium bicarbonate cotransporter 2 (NBCe2) was detected in the peripheral blood neutrophils and peripheral blood mononuclear cells (PBMCs) of these patients. The effects of varying concentrations of IGU, methotrexate (MTX), dexamethasone (DXM), and S0859 (an NBCe2 inhibitor) on NBCe2, PAD2, PAD4, and citrullinated histone H3 (cit-H3) levels in, migration ability of, and cytokine production from neutrophils and PBMCs were examined. RESULTS: Our findings showed that in patients with RA, citrullinated protein production by peripheral blood neutrophils instead of PBMCs, which showed higher NBCe2 expression levels, increased with an increase in the bicarbonate concentration. In addition, tumor necrosis factor-alpha (TNF-α) promoted NBCe2 expression in neutrophils from patients with RA. Furthermore, we revealed that the inhibitory effects of IGU on neutrophil NBCe2 and cit-H3 levels, degrees of inhibition of neutrophil and PBMC migration, and suppression of interleukin 6, TNF-α, and metalloproteinase-9 secretion from neutrophil-like differentiated HL-60 cells did not substantially differ from those of MTX, DXM, and S0859 at specific doses. CONCLUSIONS: Bicarbonate promotes protein citrullination and inflammation in RA via NBCe2, and IGU can downregulate NBCe2.

New insights into MAIT cells in autoimmune diseases.

Mucosal-associated invariant T (MAIT) cells are resident T cells that express semi-invariant TCR chains and are restricted by monomorphic major histocompatibility complex (MHC) class I-related molecules (MR1). MAIT cells can be activated by microbial-specific metabolites (MR1-dependent mode) or cytokines (MR1-independent mode). Activated MAIT cells produce chemokines, cytotoxic molecules (granzyme B and perforin), and proinflammatory cytokines (IFN-γ, TNF-α, and IL-17), to clear pathogens and target infected cells involved in the pro-inflammatory, migratory, and cytolytic properties of MAIT cells. MAIT cells produce pro-inflammatory cytokines in the target organs of autoimmune diseases and contribute to the development and progression of autoimmune diseases. This article reviews the biological characteristics, activation mechanism, dynamic migration, and dual functions of MAIT cells, and focuses on the mechanism and potential application of MAIT cells in the early diagnosis, disease activity monitoring, and therapeutic targets of autoimmune diseases, to lay a foundation for future research.

Dynamic Variations in Gut Microbiota in Ankylosing Spondylitis Patients Treated with Anti-TNF-α for Six Months.

Ankylosing spondylitis (AS) is known as a microbiome-driven disease; however, the current understanding of microbiota dynamics in AS is limited. In the present study, we conducted a 16S rDNA sequence-based microbiota survey of 97 fecal samples from healthy subjects and AS patients at baseline, 1, 3 and 6 months after anti-TNF-α treatment to demonstrate the dynamic characteristic variations of gut microbiota in AS patients. The goal of this experiment is to explore the values of gut microbiota as biomarkers of disease activity and therapeutic responses to anti-TNF-α. We found that the relative abundance of microbiota in AS patients treated with anti-TNF-α differed at various time points and distinguished 4 groups: the higher and lower than healthy control (HC) level groups throughout the study and the unchanged and restored to HC levels groups. The characteristic increases of microbes in AS patients were f_Prevotellaceae and f_Actinomycetaceae In HC, the characteristic increase was f_Lachnospiraceae BASDAI positively correlated with the relative abundance of g_Escherichina-Shigella and g_Klebsiella, but negatively correlated with f_Lachnospiraraceae at baseline. (r=0.544, P=0.013, r=0.509, P=0.022 and r=-0.577, P=0.008, respectively). The beta-diversity of microbiota in AS at baseline was lower than HC at the same level (P<0.01) and restored to normal values one month after treatment. In conclusion, the variation of gut microbiota is dynamic. Therefore, some microbes can be used as indicators for monitoring disease activity and therapeutic responsiveness during treatment.

Dynamic changes in gut microbiota under the influence of smoking and TNF-α-blocker in patients with ankylosing spondylitis.

OBJECTIVES: This study aimed to investigate the relationship among smoking, TNF-α-blocker therapy, and the dynamic changes in gut microbiota in patients with ankylosing spondylitis (AS). METHODS: Using a 16S rRNA sequence, 98 fecal samples of 20 AS patients collected after 0, 1, 3 and 6 months of anti-TNF-α treatment and from 20 matched health controls were examined. The variation in composition, abundance, and diversity of gut microbiota was analyzed. The dynamic effects of smoking and treatment on gut microbiota and therapeutic efficacy in AS patients were studied. RESULTS: The increased relative abundance of microbiota in AS nonsmokers was g_Comamonas and g_Desulfovibrio, while that in AS smokers was g_Actinomyces, g_Collinsella, g_Lachnospiraceae_UCG-008, and g_Paraprevotella. The relative abundance of gut microbiota showed dynamic variation. The improvement rate of ASDAS in AS nonsmokers was higher than that in AS smokers (2.297 vs 1.736) after anti-TNF-α treatment. The ß-diversity of gut microbiota in AS smokers was lower than that in AS nonsmokers and improved with treatment. CONCLUSIONS: Both smoking and TNF-α-blocker had significant effects on the composition, relative abundance, and diversity of gut microbiota in AS patients. The AS smokers characteristically shared g_Collinsella and g_Dorea. The relative abundance of gut microbiota revealed high variability and was in dynamic fluctuation during treatment. The response of gut microbiota to anti-TNF-α treatment was found to be heterogeneous and selective. AS nonsmokers showed a greater improvement rate of ASDAS-CRP with treatment than AS smokers did. The AS smokers showed a lower ß-diversity of gut microbiota, and improved after treatment. Key Points • Characterized the dynamic variation in gut microbiota in AS patients classified as smokers and nonsmokers during treatment with anti-TNF-α. • Confirmed the interaction between smoking, anti-TNF-α therapy, and gut microbiota.

Comparison of the effectiveness on intra-articular and subcutaneous TNF inhibitor in rheumatoid arthritis patients.

The objective of this study is to evaluate the efficacy of single intra-articular (IA) injection of tumor necrosis factor α (TNFα) inhibitor in knee joints comparing with subcutaneous injection in rheumatoid arthritis (RA) patients. Forty-eight RA patients with 73 knee arthritis were divided into three groups, group A: received a single injection of TNF inhibitor into knee joints; group B: received regular subcutaneous injection; and group C: received both of the regimen as groups A and B. Ultrasound, erythrocyte sedimentation rate, C-reactive protein (CRP), patients' global visual analogue scale (VAS), and 28-joint Disease Activity Score (DAS28) were collected pre- and post-therapy 4 weeks. The results of the study are as follows: (1) CRP, VAS, and DAS28 of all groups improved significantly post-therapy (p < 0.05); (2) After therapy, synovial hypertrophy (SH) decreased significantly from 4.40 ± 1.86 mm to 2.74 ± 1.88 mm (p < 0.05) and power Doppler (PD) signal decreased significantly from 2.63 ± 0.75 to 1.50 ± 0.93 (p < 0.01) in group A. Synovial effusion (SE), SH, and PD showed no significant improvement in group B. SE decreased significantly from 9.84 ± 4.70 mm to 5.89 ± 4.47 mm (p < 0.05), SH decreased significantly from 4.52 ± 1.97 mm to 2.49 ± 1.73 mm (p < 0.01), and PD decreased significantly from 2.46 ± 0.66 to 1.38 ± 1.04 (p < 0.01) in group C; and (3) The improvement rate of SH and PD in both groups A and C was obviously higher than that of group B (p < 0.05). Single IA injection of TNFα inhibitor was an effective treatment in improvement of SH and PD of knee joints than subcutaneous injection in RA patients.

miR­137 decreases proliferation, migration and invasion in rheumatoid arthritis fibroblast­like synoviocytes.

MicroRNA-137 (miR-137) is involved in cell proliferation, migration, invasion and apoptosis in a variety of cells. However, the role of miR­137 in rheumatoid arthritis (RA) remains unclear. The present study aimed to identify the biological roles of miR­137 in RA. The expression of miR­137 in RA fibroblast­like synoviocytes (RA­FLS) and in normal control FLS was detected by reverse transcription­quantitative polymerase chain reaction (RT­qPCR). The effects of miR­137 on RA­FLS proliferation, migration and invasion were also determined using MTT, wound healing and Transwell invasion assays, respectively. The effects of miR­137 on inflammatory cytokine expression in RA­FLS were assessed by ELISA. Bioinformatics databases (TargetScan and miRanda), luciferase reporter assays, RT­qPCR and western blotting assays were conducted to identify potential target genes. miR­137 expression was decreased in RA­FLS compared with expression in normal control FLS. Overexpression of miR­137 resulted in a significant reduction in RA­FLS proliferation, migration and invasion, and decreased the expression of inflammatory cytokines of RA­FLS. In addition, bioinformatics analysis and luciferase reporter assays indicated that miR­137 may target the 3'­untranslated region of C­X­C motif chemokine ligand 12 (CXCL12), which was confirmed by RT­qPCR and western blot analyses. These results further demonstrated that miR­137may serve an inhibitory role in RA by targeting CXCL12 expression, and miR­137 may be a potential target for the treatment of RA.

[Clinical features and disease activity index of Behçet's disease].

OBJECTIVE: The clinical features and two disease activity assessment methods of Behçet's disease were evaluated in order to guide clinical management. METHODS: A total of 116 patients with Behçet's disease from China-Japan Union Hospital of Jilin University in 2007-2014 were analyzed retrospectively for the gender and age distribution as well as clinical features of multisystem involvement. The correlations of Behçet's Disease Current Activity Form (BDCAF) and electronic medical record (EMR)-based activity index (EMRAI) scoring systems with clinical data were compared in Chinese patients for the first time, and clinical suggestion was raised. RESULTS: Behçet's disease was commonly seen in young adults with age between 21-40 years old with mean course of four years.Males had longer duration than females (9.5 years vs 4.0 years, P<0.05), and vasculopathy was more commonly seen in males (11.9% vs 1.36%, P<0.05), while females had wider age distribution. BDCAF and EMRAI scoring systems were positively correlated with each other; the former was well associated with laboratory inflammatory indices, and the latter was simplified for application. CONCLUSIONS: The clinical manifestation of Behçet's disease varies with different gender; BDCAF and EMRAI scoring system well correlate with the laboratory inflammatory indices of patients, and can indicate the disease activity.

Interleukin-34 in rheumatoid arthritis: potential role in clinical therapy.

OBJECTIVE: To investigate, whether interleukin (IL)-34 can be used as marker for treatment effectiveness in rheumatoid arthritis (RA). METHODS: Serum samples were collected from 35 healthy participants and 83 patients with RA before as well as 4 weeks and 12 weeks after treatment initiation with the tumor necrosis factor α (TNF-α) inhibitor Etanercept. Related clinical data and hand radiograms of the patients were evaluated and serum IL-34, IL-6, IL-8, TNF-α, matrix metalloproteinase-3 (MMP-3) in addition to anti-cyclic citrullinated peptide (CCP) antibody concentrations were measured by ELISA. RESULTS: Serum concentrations of IL-34, IL-6, IL-8, TNF-α, MMP-3 and anti-CCP antibodies were markedly elevated in RA patients compared with controls (P<0.001), significantly decreased during treatment and correlated with erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) and RA disease activity (P<0.05). IL-34 correlated withIL-6, IL-8, TNF-α, MMP-3 and anti-CCP antibodies in RA patients at baseline (P<0.01) and also with IL-8, MMP-3, IL-6, and DAS28 changes during therapy. Patients in stage III of hand X-ray RA scores had higher IL-34 serum concentrations than in stage II (P<0.05). IL-34 level decreased significantly (P<0.01) starting from 4 weeks after therapy initiation. CONCLUSIONS: IL-34 serum concentrations correlated with inflammatory cytokines before and during therapy and were significantly higher in stage III of hand X-ray score patients than in stage II participants. IL-34 might be used both as a biomarker for RA diagnosis and therapy efficiency.

[Bone mineral density and disease activity in untreated systemic lupus erythematosus patients].

OBJECTIVE: To determine the effects of disease activity and other risk factors on bone mineral density (BMD) in untreated systemic lupus erythematosus (SLE). METHODS: Lumbar and hip BMD were determined by dual energy X-ray absorptiometry (DXA) in 50 healthy controls and 120 premenopausal SLE females from Department of Rheumatology & Immunology, Third Hospital of Medical College of Jilin University during the period of 2010 - 2012. The SLE patients were divided into 2 groups, i.e. untreated and treated with glucocorticoid and immunosuppressives. Simple and multiple linear regression analyses were performed to determine the associations between BMD and disease-related variables. To completely eliminate the influences of glucocorticoid treatment on the results, the untreated SLE patients were chosen to investigate the risk factors with regression analysis. RESULTS: In femoral neck, greater trochanter and total hip, both the treated and untreated SLE patients had significantly lower BMD than the healthy controls (P < 0.01). In greater trochanter, the treated SLE group had significantly lower BMD than the untreated group. The BMD of left and right femoral neck of the former were botj -0.06 while that of the later -0.11 and -0.12 respectively (P < 0.05). Regression analysis showed that long disease duration and high (SLE disease activity index) SLEDAI were the risk factors of low BMD (P < 0.05), especially high SLEDAI. CONCLUSION: SLE itself may result in low BMD, especially in patients with high SLEDAI. Hip joints are predominantly affected. Long disease duration is also closely associated with low BMD in SLE.