Mammalian Glycosylation Patterns Protect Citrullinated Chemokine MCP-1/CCL2 from Partial Degradation.

Monocyte chemoattractant protein-1 (MCP-1/CCL2) is a potent chemotactic agent for monocytes, primarily produced by macrophages and endothelial cells. Significantly elevated levels of MCP-1/CCL2 were found in synovial fluids of patients with rheumatoid arthritis (RA), compared to osteoarthritis or other arthritis patients. Several studies suggested an important role for MCP-1 in the massive inflammation at the damaged joint, in part due to its chemotactic and angiogenic effects. It is a known fact that the post-translational modifications (PTMs) of proteins have a significant impact on their properties. In mammals, arginine residues within proteins can be converted into citrulline by peptidylarginine deiminase (PAD) enzymes. Anti-citrullinated protein antibodies (ACPA), recognizing these PTMs, have become a hallmark for rheumatoid arthritis (RA) and other autoimmune diseases and are important in diagnostics and prognosis. In previous studies, we found that citrullination converts the neutrophil attracting chemokine neutrophil-activating peptide 78 (ENA-78) into a potent macrophage chemoattractant. Here we report that both commercially available and recombinant bacterially produced MCP-1/CCL2 are rapidly (partially) degraded upon in vitro citrullination. However, properly glycosylated MCP-1/CCL2 produced by mammalian cells is protected against degradation during efficient citrullination. Site-directed mutagenesis of the potential glycosylation site at the asparagine-14 residue within human MCP-1 revealed lower expression levels in mammalian expression systems. The glycosylation-mediated recombinant chemokine stabilization allows the production of citrullinated MCP-1/CCL2, which can be effectively used to calibrate crucial assays, such as modified ELISAs.

Relationship between falls and the use of hypnotics, antidepressants, antipsychotics, and anxiolytics in patients with rheumatoid arthritis: A cross-sectional study.

Objectives This cross-sectional study aimed to determine the relationship between falls and use of psychotropic medications in patients with rheumatoid arthritis. Methods The psychotropic medication group included patients with rheumatoid arthritis prescribed psychotropic medications (hypnotics/sedatives, antidepressants, antipsychotics, and anxiolytic [benzodiazepines] drugs). Poisson regression with robust variance was performed to investigate the relationship between falls and the use of psychotropic medications, with adjustment for age, sex, rheumatoid arthritis disease activity, stroke, dementia, diabetes mellitus, and osteoarthritis. Results Of the 307 patients enrolled, 49 (16.0%) used psychotropic medications, and 70 (22.8%) experienced at least one fall per year. Nineteen of the 49 patients (38.8%) taking psychotropic medications and 51 of 258 (19.8%) not taking psychotropic medications experienced at least one fall per year. Falls were significantly more frequent in the group with psychotropic medications than in the group without psychotropic medications (adjusted incidence rate ratio, 1.63; 95% confidence interval; 1.08-2.48, p = 0.02). No relationship was found between the number of falls and the use of psychotropic medications (adjusted incidence rate ratio, 1.16; 95% confidence interval; 0.39-3.44, p = 0.78). Conclusions There may be a relationship between psychotropic medication use and falls in patients with rheumatoid arthritis.

Effectiveness and safety of subcutaneous abatacept in biologic-naïve RA patients at Week 52: A Japanese multicentre investigational study (ORIGAMI study).

OBJECTIVES: To evaluate the effectiveness and safety of abatacept over 52 weeks in biologic-naïve rheumatoid arthritis (RA) patients with moderate disease activity in the prospective, 5-year, observational study (ORIGAMI study) in Japan. METHODS: Abatacept (125 mg) was administered subcutaneously once a week. Clinical outcomes included Simplified Disease Activity Index (SDAI) remission at Week 52 (primary endpoint), Japanese Health Assessment Questionnaire (J-HAQ), EuroQol 5-Dimension Questionnaire (EQ-5D), treatment retention, and safety. The results were compared with those of conventional synthetic disease-modifying antirheumatic drug (csDMARD) controls from the ongoing Institute of Rheumatology, Rheumatoid Arthritis (IORRA) registry. RESULTS: Overall, 325 patients were enrolled, with a mean age of 66.9 ± 12.7 years. The proportion of patients achieving SDAI remission (≤3.3) at Week 52 was 18.9% (95% CI: 14.3-23.6) and low disease activity (≤11) was 53.3% (95% CI: 47.4-59.1). A significant improvement was observed in J-HAQ and EQ-5D over 52 weeks in both the abatacept and csDMARD groups. The probability of abatacept treatment retention at Week 52 was 69.9% (95% CI: 64.7-75.5). Adverse events and serious adverse events were reported in 50.0% and 12.1% of patients, respectively. CONCLUSIONS: Abatacept significantly improved disease activity, physical disability, and quality of life for up to 52 weeks in RA patients in a real-world setting.

Inhibition of hepatocyte growth factor/c-Met signalling abrogates joint destruction by suppressing monocyte migration in rheumatoid arthritis.

OBJECTIVES: To determine the expression of hepatocyte growth factor (HGF) in RA biological fluids, the role of HGF in monocyte migration and the therapeutic effect of the c-Met inhibitor savolitinib in an arthritis model mice. METHODS: HGF/c-Met expression in serum, SF and synovial tissues (STs) obtained from RA patients and controls, as well as RA fibroblast-like synoviocytes (FLSs), was evaluated by ELISA and immunostaining. To determine the function of HGF in RA SF, we preincubated RA SF with a neutralizing anti-HGF antibody and measured the chemotactic ability of a human acute monocytic leukaemia cell line (THP-1). Additionally, examinations were conducted of SKG mice treated with savolitinib for 4 weeks. RESULTS: HGF levels in serum from RA patients were significantly higher than those in the controls and were decreased by drug treatment for 24 weeks. Additionally, the HGF level in SF from RA patients was higher than that in SF from OA patients. HGF and c-Met expression was also noted in RA STs. Stimulation of RA FLSs with TNF-α increased HGF/c-Met expression in a concentration-dependent manner, and c-Met signal inhibition suppressed production of fractalkine/CX3CL1 and macrophage inflammatory protein-1α/CCL3. When HGF was removed by immunoprecipitation, migration of THP-1 in RA SF was suppressed. In SKG mice, savolitinib significantly suppressed ankle bone destruction on µCT, with an associated reduction in the number of tartrate-resistant acid phosphatase-positive osteoclasts. CONCLUSION: HGF produced by inflammation in synovium of RA patients activates monocyte migration to synovium and promotes bone destruction via a chemotactic effect and enhanced chemokine production.

A disintegrin and metalloproteinase (ADAM)-10 as a predictive factor for tocilizumab effectiveness in rheumatoid arthritis.

OBJECTIVES: A disintegrin and metalloproteinase (ADAM)-10 is expressed in rheumatoid arthritis (RA). In this study, we focused on ADAM-10 as a predictive factor for the treatment with biologics in RA. METHODS: The levels of ADAM-10 and fractalkine/CX3CL1 in RA and healthy controls serum were measured using enzyme-linked immunosorbent assays. Fifteen patients were treated with adalimumab (ADA), and 20 patients were treated with tocilizumab (TCZ). RESULTS: ADAM-10 positively correlated with fractalkine/CX3CL1 in the sera of RA patients and was presented at a significantly higher level compared to that in normal serum (487 ± 80 pg/ml and 85 ± 33 pg/ml, respectively, p < 0.05). ADAM-10 highly correlates with fractalkine/CX3CL1 in the sera of RA patients. The level of ADAM-10 decreased after the treatment with TCZ but not with ADA. In addition, we found that the level of ADAM-10 in TCZ responders was significantly higher than that of the TCZ nonresponders at 24 weeks (619 ± 134 pg/ml and 109 ± 25 pg/ml, respectively). Multiple regression analysis showed that ADAM-10 was only identified as independent predictive variable for the improvement of DAS28 (ESR) at 24 weeks. CONCLUSIONS: ADAM-10 may be a predictor of the effectiveness of TCZ in treating RA.

A key role for Fut1-regulated angiogenesis and ICAM-1 expression in K/BxN arthritis.

OBJECTIVES: Angiogenesis contributes to the pathogenesis of rheumatoid arthritis. Fucosyltransferases (Futs) are involved in angiogenesis and tumour growth. Here, we examined the role of Fut1 in angiogenesis and K/BxN serum transfer arthritis. METHODS: We examined Fut1 expression in human dermal microvascular endothelial cells (HMVECs) by quantitative PCR. We performed a number of angiogenesis assays to determine the role of Fut1 using HMVECs, Fut1 null (Fut1(-/-)), and wild type (wt) endothelial cells (ECs) and mice. K/BxN serum transfer arthritis was performed to determine the contribution of Fut1-mediated angiogenesis in Fut1(-/-) and wt mice. A static adhesion assay was implemented with RAW264.7 (mouse macrophage cell line) and mouse ECs. Quantitative PCR, immunofluorescence and flow cytometry were performed with Fut1(-/-) and wt ECs for adhesion molecule expression. RESULTS: Tumour necrosis factor-α induced Fut1 mRNA and protein expression in HMVECs. HMVECs transfected with Fut1 antisense oligodeoxynucleotide and Fut1(-/-) ECs formed significantly fewer tubes on Matrigel. Fut1(-/-) mice had reduced angiogenesis in Matrigel plug and sponge granuloma angiogenesis assays compared with wt mice. Fut1(-/-) mice were resistant to K/BxN serum transfer arthritis and had decreased angiogenesis and leucocyte ingress into inflamed joints. Adhesion of RAW264.7 cells to wt mouse ECs was significantly reduced when Fut1 was lacking. Fut1(-/-) ECs had decreased intercellular adhesion molecule-1 (ICAM-1) expression at mRNA and protein levels compared with wt ECs. ICAM-1 was also decreased in Fut1(-/-) arthritic ankle cryosections compared with wt ankles. CONCLUSIONS: Fut1 plays an important role in regulating angiogenesis and ICAM-1 expression in inflammatory arthritis.

ADAM-10 is overexpressed in rheumatoid arthritis synovial tissue and mediates angiogenesis.

OBJECTIVE: To examine the expression of ADAM-10 in rheumatoid arthritis (RA) synovial tissue (ST) and the role it plays in angiogenesis. METHODS: ADAM-10 expression was determined using immunohistology, Western blotting, and quantitative polymerase chain reaction. In order to examine the role of ADAM-10 in angiogenesis, we performed in vitro Matrigel tube formation and chemotaxis assays using human microvascular endothelial cells (HMVECs) transfected with control or ADAM-10 small interfering RNA (siRNA). To determine whether ADAM-10 plays a role in angiogenesis in the context of RA, we performed Matrigel assays using a coculture system of HMVECs and RA synovial fibroblasts. RESULTS: Endothelial cells and lining cells within RA ST expressed high levels of ADAM-10 compared with cells within osteoarthritis ST and normal ST. ADAM-10 expression was significantly elevated at the protein and messenger RNA levels in HMVECs and RA synovial fibroblasts stimulated with proinflammatory mediators compared with unstimulated cells. ADAM-10 siRNA-treated HMVECs had decreased endothelial cell tube formation and migration compared with control siRNA-treated HMVECs. In addition, ADAM-10 siRNA-treated HMVECs from the RA synovial fibroblast coculture system had decreased endothelial cell tube formation compared with control siRNA-treated HMVECs. CONCLUSION: These data show that ADAM-10 is overexpressed in RA and suggest that ADAM-10 may play a role in RA angiogenesis. ADAM-10 may be a potential therapeutic target in inflammatory angiogenic diseases such as RA.

Evidence that CXCL16 is a potent mediator of angiogenesis and is involved in endothelial progenitor cell chemotaxis : studies in mice with K/BxN serum-induced arthritis.

OBJECTIVE: To examine the possibility that CXCL16 recruits endothelial cells (ECs) to developing neovasculature in rheumatoid arthritis (RA) synovium. METHODS: We utilized the RA synovial tissue SCID mouse chimera system to examine human microvascular EC (HMVEC) and human endothelial progenitor cell (EPC) recruitment into engrafted human synovium that was injected intragraft with CXCL16-immunodepleted RA synovial fluid (SF). CXCR6-deficient and wild-type (WT) C57BL/6 mice were primed to develop K/BxN serum-induced arthritis and evaluated for angiogenesis. HMVECs and EPCs from human cord blood were also examined for CXCR6 expression, by immunofluorescence and assessment of CXCL16 signaling activity. RESULTS: CXCR6 was prominently expressed on human EPCs and HMVECs, and its expression on HMVECs could be up-regulated by interleukin-1ß. SCID mice injected with CXCL16-depleted RA SF exhibited a significant reduction in EPC recruitment. In experiments using the K/BxN serum-induced inflammatory arthritis model, CXCR6(-/-) mice showed profound reductions in hemoglobin levels, which correlated with reductions in monocyte and T cell recruitment to arthritic joint tissue compared to that observed in WT mice. Additionally, HMVECs and EPCs responded to CXCL16 stimulation, but exhibited unique signal transduction pathways and homing properties. CONCLUSION: These results indicate that CXCL16 and its receptor CXCR6 may be a central ligand/receptor pair that is closely associated with EPC recruitment and blood vessel formation in the RA joint.

A novel role for inducible Fut2 in angiogenesis.

RATIONALE: Angiogenesis plays an important role in wound healing and tumor growth. Fucosyltransferases synthesize fucosylated glycans and may play a major role in vascular biology. OBJECTIVE: To examine the role of an alpha(1,2) fucosyltransferase (Fut2) in angiogenesis. METHODS AND RESULTS: We found that Fut2 mRNA and protein expression is inducible in human dermal microvascular endothelial cells (HMVECs). After finding that Fut2 is inducible in HMVECs, we examined if Fut2 contributes to angiogenesis. We found that Fut2 null endothelial cell (EC) migration and tube formation were significantly less compared to wild type (wt) ECs. Angiogenesis was impaired in Fut2 null compared to wt mice in the mouse Matrigel plug and the sponge granuloma angiogenesis assays. To assess the characteristics of Fut2 null ECs in vivo, we performed Matrigel plug angiogenesis assays in wt mice using Fut2 null and wt mouse ECs. We found a significant decrease in Fut2 null EC incorporation in neoangiogenesis compared to wt ECs. ERK1/2 activation, fibroblast growth factor receptor2, and vascular endothelial growth factor expression were less in Fut2 null ECs, suggesting a possible mechanism of impaired angiogenesis when Fut2 is lacking. CONCLUSIONS: These data suggest a novel role for Fut2 as a regulator of angiogenesis.

Elevated serum levels of macrophage migration inhibitory factor and their significant correlation with rheumatoid vasculitis disease activity.

Macrophage migration inhibitory factor (MIF) is recognized to be an important mediator in several inflammatory disorders, including rheumatoid arthritis (RA) and vasculitis. To evaluate the role of MIF in rheumatoid vasculitis (RV), we determined serum levels of MIF by enzyme-linked immunosorbent assay in RA patients with and without vasculitis and assessed their relationship to disease activity. Serum was obtained from 95 RA patients during active disease states [49 without vasculitis, 35 with extra-articular manifestations without histologically proven vasculitis, and 11 with histologically proven vasculitis] and from 22 healthy individuals. Vasculitis disease activity was assessed using the Birmingham Vasculitis Activity Score (BVAS). MIF levels were significantly higher in RA patients than in controls. Moreover, MIF levels were significantly higher in RA patients with vasculitis than in those without vasculitic complications. In all RA patients, a statistically significant positive correlation was observed between serum MIF levels and each of the following: serum levels of C-reactive protein, rheumatoid factor, and thrombomodulin; and the erythrocyte sedimentation rate. In the RV group, the elevation of MIF levels correlated with the BVAS. Our findings suggest that MIF may serve as an additional serologic inflammatory marker of disease activity in RV, and it may be implicated in the pathogenesis of RV.

Eotaxin-1/CCL11 is involved in cell migration in rheumatoid arthritis.

Eotaxin-1 (CCL11) induces the migration of different leukocyte types by interacting with CCR3. In rheumatoid arthritis (RA), fibroblast-like synoviocytes (FLS) are pathogenic effectors and a major CCR3-expressing cell. The aim of this study was to investigate the expression and function of CCL11 in RA FLS. The expression of CCL11 and CCR3 was evaluated by ELISA, immunofluorescence and quantitative PCR analysis. The CCL11 levels in serum and synovial fluids (SFs) from RA patients were significantly higher than those in serum from healthy controls and SFs from osteoarthritis patients. CCL11 and CCR3 were expressed in the RA synovial tissue lining layers. The secretion of CCL11 in RA FLS-conditioned medium and the mRNA expression of CCL11 and CCR3 were induced by TNF-α. Furthermore, CCL11 induced the mRNA expression of CCL11 and CCR3. Application of a CCR3 antagonist reduced TNF-α-induced CCL11 secretion from RA FLS. CCL11 induced the migration of RA FLS and monocytes. RA FLS migration was decreased by treatment with CCL11 siRNA. The migration of monocytes to medium conditioned with CCL11 siRNA-transfected and TNF-α-stimulated RA FLS was reduced. These data indicate that the self-amplification of CCL11 via CCR3 may play an important role in cell migration in RA.

Dermatomyositis complicated with hemorrhagic shock of the iliopsoas muscle on both sides and the thigh muscle.

A 65-year-old Japanese woman, diagnosed with dermatomyositis with myopathy and characteristic skin lesion, was intravenously administered methylprednisolone 500 mg per day for 3 days, followed by prednisolone 60 mg po per day. Four days later, she went into shock. Computed tomography of the abdomen showed hematoma in the iliopsoas muscle on both sides and a thigh muscle. Intravenously administered heparin was stopped, and 4 U of packed cells and 4 U of fresh frozen plasma were transfused. The patient subsequently developed pulmonary edema requiring assisted ventilation, and made a successful recovery, returning home after a short period of intensive rehabilitation.

Role of Cytokines in EGPA and the Possibility of Treatment with an Anti-IL-5 Antibody.

Eosinophilic granulomatosis with polyangiitis (EGPA) is a type of systemic vasculitis with eosinophilia in the peripheral blood, which is preceded by bronchial asthma or allergic disease. EGPA is pathologically characterized by microangiopathy granulomatosis vasculitis. Vasculitis can be exacerbated and cause central nervous system and cardiovascular disorders and gastrointestinal perforation. Histological examination reveals eosinophil infiltration and granulomas in lesions in areas such as the lung, nervous system, and skin. Laboratory tests show inflammatory findings such as C-reactive protein (CRP) elevation, increased eosinophils, elevated serum IgE, and elevated myeloperoxidase-anti-neutrophil cytoplasmic antibodies (MPO-ANCA). MPO-ANCA is positive in approximately 40-70% of cases of this disease. EGPA is a necrotizing vasculitis that affects small- and medium-sized blood vessels; however, it differs from other types of ANCA-related vasculitis (such as microscopic polyangiitis and granulomatosis) because it is preceded by bronchial asthma and eosinophilia in the blood and tissues. Treatment with immunosuppressive agents such as steroids or cyclophosphamide depends on the Five Factor Score, which predicts the prognosis and severity of the condition. If the effect of appropriate treatment with steroids is insufficient, the anti-interleukin-5 antibody mepolizumab can be administered. The combination of mepolizumab with standard treatment leads to a significantly longer duration of remission, a higher proportion of patients who achieve sustained remission, and less steroid use than with a placebo.

A Disintegrin and Metalloprotease 15 is Expressed on Rheumatoid Arthritis Synovial Tissue Endothelial Cells and may Mediate Angiogenesis.

A disintegrin and metalloprotease 15 (ADAM15) is involved in several malignancies. In this study, we investigated the role of ADAM15 in rheumatoid arthritis (RA) angiogenesis. Soluble ADAM15 (s-ADAM15) in serum from RA and normal (NL) subjects was measured using ELISA. To determine membrane-anchored ADAM15 (ADAM15) expression in RA synovial tissues, immunohistochemistry was performed. To examine the role of ADAM15 in angiogenesis, we performed in vitro Matrigel assays and monocyte adhesion assays using human umbilical vein endothelial cells (HUVECs) transfected with ADAM15 siRNA. Finally, to investigate whether angiogenic mediators were affected by ADAM15, cytokines in ADAM15 siRNA-transfected HUVEC-conditioned medium were measured. ADAM15 was significantly higher in RA serum than in NL serum. ADAM15 was also expressed on RAST endothelial cells. ADAM15 siRNA-treated HUVECs had decreased EC tube formation in response to RA synovial fluids compared with non-treated HUVECs. The adhesion index of ADAM15 siRNA-transfected HUVECs was significantly lower than the adhesion index of control siRNA-transfected HUVECs. ENA-78/CXCL5 and ICAM-1 were decreased in tumor necrosis factor (TNF)-α-stimulated ADAM15 siRNA-transfected HUVEC-conditioned medium compared with TNF-α-stimulated control siRNA-transfected HUVEC-conditioned medium. These data show that ADAM15 plays a role in RA angiogenesis, suggesting that ADAM15 might be a potential target in inflammatory diseases such as RA.

Peficitinib Inhibits the Chemotactic Activity of Monocytes via Proinflammatory Cytokine Production in Rheumatoid Arthritis Fibroblast-Like Synoviocytes.

Background: This study was performed to examine the effects of the Janus kinase (JAK) inhibitor peficitinib on fibroblast-like synoviocytes (FLS) obtained from patients with rheumatoid arthritis (RA). Methods: To examine the expression of JAK1, JAK2, and JAK3 in RA synovial tissue (ST) and FLS, immunohistochemistry was performed. We investigated the effects of peficitinib on interleukin 6 and IL-6 receptor responses in RA FLS. Phosphorylation of STAT was determined by western blot. To examine the functional analysis of peficitinib, we performed a proliferation and chemotaxis assays with FLS using THP-1 and peripheral blood mononuclear cells (PBMC). The inflammatory mediator expression of FLS was estimated by enzyme-linked immunosorbent assay. Results: JAK1, JAK2, and JAK3 were expressed in RA STs and FLS. Phosphorylation of STAT1, STAT3, and STAT5 in RA FLS was suppressed by peficitinib in a concentration-dependent manner. Peficitinib-treated RA FLS-conditioned medium reduced THP-1 and PBMC migration (p < 0.05) and proliferation of RA FLS (p < 0.05). Peficitinib suppressed the secretion of MCP-1/CCL2 in the RA FLS supernatant (p < 0.05). Conclusion: Peficitinib suppressed the JAK-STAT pathway in RA FLS and also suppressed monocyte chemotaxis and proliferation of FLS through inhibition of inflammatory cytokines.

Citrullinated Inhibitor of DNA Binding 1 Is a Novel Autoantigen in Rheumatoid Arthritis.

OBJECTIVE: To explore the intrinsic role of inhibitor of DNA binding 1 (ID-1) in rheumatoid arthritis (RA) fibroblast-like synoviocytes (FLS) and to investigate whether ID-1 is citrullinated and autoantigenic in RA. METHODS: RA patient serum ID-1 levels were measured before and after infliximab treatment. RA FLS were transfected with a clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated protein 9 construct targeting ID-1 to examine the effects of ID-1 deletion. RA synovial fluid (SF) and homogenized synovial tissue (ST) were immunoprecipitated for ID-1 and measured for citrullinated residues using an enzyme-linked immunosorbent assay and Western blotting. Liquid chromatography tandem mass spectrometry (LC-MS/MS) was performed on in vitro-citrullinated recombinant human ID-1 (cit-ID-1) to localize the sites of citrullination. Normal and RA sera and SF were analyzed by immunodot blotting for anti-citrullinated protein antibodies (ACPAs) to cit-ID-1. RESULTS: RA patient serum ID-1 levels positively correlated with several disease parameters and were reduced after infliximab treatment. RA FLS displayed reduced growth and a robust increase in interleukin-6 (IL-6) and IL-8 production upon deletion of ID-1. ID-1 immunodepletion significantly reduced the levels of citrullinated residues in RA SF, and citrullinated ID-1 was detected in homogenized RA ST (n = 5 samples; P < 0.05). Immunodot blot analyses revealed ACPAs to cit-ID-1 but not to native ID-1, in RA peripheral blood (PB) sera (n = 30 samples; P < 0.001) and SF (n = 18 samples; P < 0.05) but not in normal PB sera. Following analyses of LC-MS/MS results for citrullination sites and corresponding reactivity in immunodot assays, we determined the critical arginines in ID-1 for autoantigenicity: R33, R52, and R121. CONCLUSION: Novel roles of ID-1 in RA include regulation of FLS proliferation and cytokine secretion as well as autoantigenicity following citrullination.

ADAM-17 is expressed on rheumatoid arthritis fibroblast-like synoviocytes and regulates proinflammatory mediator expression and monocyte adhesion.

BACKGROUND: To examine the expression of ADAM-17 in rheumatoid arthritis (RA) biological fluids and the role it plays in monocyte adhesion to RA fibroblast-like synoviocytes (FLSs). METHODS: ADAM-17 expression was measured by enzyme-linked immunosorbent assays (ELISAs) in serum from normal (NL) subjects, osteoarthritis (OA) patients, and RA patients. We also analyzed the correlation between ADAM-17 and disease activity score 28 (DAS28) in RA. To determine expression of ADAM-17 in RA synovial tissues (STs) and RA FLS, we performed immunofluorescence analyses. To determine the role of ADAM-17 in RA, we transfected RA FLSs with small interfering RNA (siRNA) against ADAM-17. THP-1 adhesion to ADAM-17 siRNA-transfected RA FLSs was measured. Finally, adhesion molecules on ADAM-17 siRNA-transfected RA FLSs were measured using cell surface ELISAs. RESULTS: ADAM-17 in RA serum was significantly higher than that in NL and OA serum and correlated with DAS28. ADAM-17 in RA synovial fluids was higher than that in OA synovial fluids. ADAM-17 was expressed on RA cells lining STs and RA FLSs. THP-1 adhesion to ADAM-17 siRNA-transfected RA FLSs was decreased compared with that to control siRNA-transfected RA FLSs. ICAM-1 on TNF-α-stimulated ADAM-17 siRNA-transfected RA FLSs was significantly decreased compared with that on control siRNA-transfected RA FLSs. CONCLUSIONS: These data indicate that ADAM-17 is expressed on RA STs and plays a role in RA inflammation by regulating monocyte adhesion to RA FLSs. ADAM-17 might be an important inflammatory mediator in inflammatory diseases such as RA.

Correction to: ADAM-17 is expressed in the inflammatory myopathy and is involved with interstitial lung disease.

The original version of this article, unfortunately, contained errors. Figure citation, caption, image and updated sentence in the Result section are now presented correctly in this article.

ADAM-17 is expressed in the inflammatory myopathy and is involved with interstitial lung disease.

The "A disintegrin and metalloprotease" (ADAM) family is thought to play an important role in tissue destruction and inflammatory reactions. ADAM-17 was first described as the protease responsible for tumor necrosis factor (TNF)-α shedding. Here, we have shown the expression of ADAM-17 in inflammatory myopathy and demonstrated the role of inflammation in interstitial lung diseases (ILD). ADAM-17 in inflammatory myopathy serum [polymyositis (n = 26), dermatomyositis (n = 34), and clinically amyopathic dermatomyositis (n = 10)] and healthy control (n = 19) was measured using enzyme-linked immunosorbent assay. The relationship between ADAM-17 and clinical data was examined. Finally, we performed immunohistological analysis to investigate the expression of ADAM-17 on the muscles of the inflammatory myopathy patients. ADAM-17 in inflammatory myopathy was significantly higher than that in healthy control (mean ± SEM, 1048 ± 312 and 36 ± 18 pg/ml, respectively; p < 0.05). ADAM-17 in post-treatment with corticosteroid and/or immunosuppressant serum was significantly decreased compared with that in pre-treatment serum (1465 ± 562 and 1059 ± 503 pg/ml, respectively; p < 0.01). ADAM-17 was significantly positively correlated with fractalkine/CX3CL1 and CXCL16. In addition, ADAM-17 in inflammatory myopathy with ILD patients (n = 46) was significantly higher than that in non-ILD patients (n = 24) (1379 ± 454 and 413 ± 226 pg/ml, respectively; p < 0.05). We found the expression of ADAM-17 on muscle biopsy tissue. ADAM-17 is expressed in inflammatory myopathies especially ILD, suggesting that ADAM-17 plays a role in lung fibrosis. ADAM-17 may be a potential target in inflammatory myopathies with ILD.

A unique role for galectin-9 in angiogenesis and inflammatory arthritis.

BACKGROUND: Galectin-9 (Gal-9) is a mammalian lectin secreted by endothelial cells that is highly expressed in rheumatoid arthritis synovial tissues and synovial fluid. Roles have been proposed for galectins in the regulation of inflammation and angiogenesis. Therefore, we examined the contribution of Gal-9 to angiogenesis and inflammation in arthritis. METHODS: To determine the role of Gal-9 in angiogenesis, we performed human dermal microvascular endothelial cell (HMVEC) chemotaxis, Matrigel tube formation, and mouse Matrigel plug angiogenesis assays. We also examined the role of signaling molecules in Gal-9-induced angiogenesis by using signaling inhibitors and small interfering RNA (siRNA). We performed monocyte (MN) migration assays in a modified Boyden chamber and assessed the arthritogenicity of Gal-9 by injecting Gal-9 into mouse knees. RESULTS: Gal-9 significantly increased HMVEC migration, which was decreased by inhibitors of extracellular signal-regulating kinases 1/2 (Erk1/2), p38, Janus kinase (Jnk), and phosphatidylinositol 3-kinase. Gal-9 HMVEC-induced tube formation was reduced by Erk1/2, p38, and Jnk inhibitors, and this was confirmed by siRNA knockdown. In mouse Matrigel plug assays, plugs containing Gal-9 induced significantly higher angiogenesis, which was attenuated by a Jnk inhibitor. Gal-9 also induced MN migration, and there was a marked increase in MN ingress when C57BL/6 mouse knees were injected with Gal-9 compared with the control, pointing to a proinflammatory role for Gal-9. CONCLUSIONS: Gal-9 mediates angiogenesis, increases MN migration in vitro, and induces acute inflammatory arthritis in mice, suggesting a novel role for Gal-9 in angiogenesis, joint inflammation, and possibly other inflammatory diseases.