Waka Yokoyama

Chemerin activates fibroblast-like synoviocytes in patients with rheumatoid arthritis

IntroductionChemerin is a chemotactic agonist identified as a ligand for ChemR23 that is expressed on macrophages and dendritic cells (DCs). In this study, we analyzed the expression of chemerin and ChemR23 in the synovium of rheumatoid arthritis (RA) patients and the stimulatory effects of chemerin on fibroblast-like synoviocytes (FLSs) from RA patients.MethodsChemerin and ChemR23 expression in the RA synovium was ascertained by immunohistochemistry and Western blot analysis. Chemerin expression on cultured FLSs was analyzed by ELISA. ChemR23 expression on FLSs was determined by immunocytochemistry and Western blot analysis. Cytokine production from FLSs was measured by ELISA. FLS cell motility was evaluated by utilizing a scrape motility assay. We also examined the stimulating effect of chemerin on the phosphorylation of mitogen-activated protein kinase (MAPK), p44/42 mitogen-activated protein kinase (ERK1/2), p38MAPK, c-Jun N-terminal kinase (JNK)1/2 and Akt, as well as on the degradation of regulator of NF-κB (IκBα) in FLSs, by Western blot analysis.ResultsChemerin was expressed on endothelial cells and synovial lining and sublining cells. ChemR23 was expressed on macrophages, immature DCs and FLSs and a few mature DCs in the RA synovium. Chemerin and ChemR23 were highly expressed in the RA synovium compared with osteoarthritis. Chemerin and ChemR23 were expressed on unstimulated FLSs. TNF-α and IFN-γ upregulated chemerin production. Chemerin enhanced the production of IL-6, chemokine (C-C motif) ligand 2 and matrix metalloproteinase 3 by FLSs, as well as increasing FLS motility. The stimulatory effects of chemerin on FLSs were mediated by activation of ERK1/2, p38MAPK and Akt, but not by JNK1/2. Degradation of IκB in FLSs was not promoted by chemerin stimulation. Inhibition of the ERK1/2, p38MAPK and Akt signaling pathways significantly suppressed chemerin-induced IL-6 production. Moreover, blockade of the p38MAPK and Akt pathways, but not the ERK1/2 pathway, inhibited chemerin-enhanced cell motility.ConclusionsThe interaction of chemerin and ChemR23 may play an important role in the pathogenesis of RA through the activation of FLSs.

Necessity of Lysophosphatidic Acid Receptor 1 for Development of Arthritis

OBJECTIVE Lysophosphatidic acid (LPA) is a bioactive lipid that binds to a group of cell surface G protein-coupled receptors (LPA receptors 1-6 [LPA1-6 ]) and has been implicated as an important mediator of angiogenesis, inflammation, and cancer growth. This study was undertaken to analyze the effects of LPA1 on the development of arthritis. METHODS Expression of LPA receptors on synovial tissue was analyzed by immunohistochemistry and quantitative reverse transcription-polymerase chain reaction. The effects of abrogation of LPA1 on collagen-induced arthritis (CIA) were evaluated using LPA1 -deficient mice or LPA1 antagonist. Migrating fluorescence-labeled CD11b+ splenocytes, which were transferred into the synovium of mice with CIA, were counted. CD4+ naive T cells were incubated under Th1-, Th2-, or Th17-polarizing conditions, and T helper cell differentiation was assessed. Osteoclast formation from bone marrow cells was examined. RESULTS LPA1 was highly expressed in the synovium of patients with rheumatoid arthritis (RA) compared with that of patients with osteoarthritis. LPA1 -deficient mice did not develop arthritis following immunization with type II collagen (CII). LPA1 antagonist also ameliorated murine CIA. Abrogation of LPA1 was associated with reductions in cell infiltration, bone destruction in the joints, and interleukin-17 production from CII-stimulated splenocytes. Infiltration of transferred CD11b+ macrophages from LPA1 -deficient mice into the synovium was suppressed compared with infiltration of macrophages from wild-type mice. LPA1 antagonist inhibited the infiltration of macrophages from wild-type mice. Differentiation into Th17, but not Th1 or Th2, and osteoclast formation were also suppressed under conditions of LPA1 deficiency or LPA1 inhibition in vitro. CONCLUSION Collectively, these results indicate that LPA/LPA1 signaling contributes to the development of arthritis via cellular infiltration, Th17 differentiation, and osteoclastogenesis. Thus, LPA1 may be a promising target molecule for RA therapy.

Cannabinoid receptor 2 as a potential therapeutic target in rheumatoid arthritis.

BackgroundSome of cannabinoids, which are chemical compounds contained in marijuana, are immunosuppressive. One of the receptors, CB receptor 1 (CB1), is expressed predominantly by the cells in the central nervous system, whereas CB receptor 2 (CB2) is expressed primarily by immune cells. Theoretically, selective CB2 agonists should be devoid of psychoactive effects. In this study, we investigated therapeutic effects of a selective CB2 agonist on arthritis.MethodsThe expression of CB2 was analyzed with immunohistochemistry and Western blotting. Interleukin (IL)-6, matrix metalloproteinase-3 (MMP-3), and chemokine (C-C motif) ligand 2 (CCL2) were quantified with enzyme-linked immunosorbent assays (ELISA). Osteoclastogenesis was assessed with tartrate-resistant acid phosphatase staining and the resorption of coated-calcium phosphate. Effect of JWH133, a selective CB2 agonist, on murine collagen type II (CII)-induced arthritis (CIA) was evaluated with arthritis score, and histological and radiographic changes. IFN-γ and IL-17 production by CII-stimulated splenocytes and serum anti-CII Ab were analyzed by ELISA.ResultsImmunohistochemistry showed that CB2 was expressed more in the synovial tissues from the rheumatoid joints than in those from the osteoarthritis joints. CB2 expression on RA FLS was confirmed with Western blot analysis. JWH133 inhibited IL-6, MMP-3, and CCL2 production from tumor necrosis factor-α-stimulated fibroblast-like synoviocytes (FLS) derived from the rheumatoid joints, and osteoclastogenesis of peripheral blood monocytes. Administration of JWH133 to CIA mice reduced the arthritis score, inflammatory cell infiltration, bone destruction, and anti-CII IgG1 production.ConclusionThe present study suggests that a selective CB2 agonist could be a new therapy for RA that inhibits production of inflammatory mediators from FLS, and osteoclastogenesis.

Structural and functional outcomes of a therapeutic strategy targeting low disease activity in patients with elderly-onset rheumatoid arthritis: a prospective cohort study (CRANE)

OBJECTIVE The aim of this study was to evaluate structural damage and physical disability in patients with elderly-onset RA (EORA) who were treated in clinical practice with a therapeutic strategy targeting low disease activity (LDA). METHODS Data from 151 MTX-naive patients (mean age 74.9 years) with EORA from a prospective, monocentric registry were analysed. Treatment was adjusted every 3 months targeting LDA [28-joint DAS using ESR (DAS28-ESR) <3.2]. Treatment was initiated with non-biologic DMARDs (nbDMARDs), followed by TNF inhibitors (TNFis) or tocilizumab. The primary outcome was change from week 0 to week 52 in the modified total Sharp score (ΔmTSS). Secondary outcomes were derived from the HAQ Disability Index (HAQ-DI) and DAS28 at week 52. Predictors of clinically relevant radiographic progression [CRRP; ΔmTSS/year more than the smallest detectable change (2.1 points)] were examined using multivariate logistic regression models. RESULTS Adherence to the treat-to-target strategy was observed in 83.4% of the 151 patients at week 24 and in 75.5% at week 52. At week 52, 67.6% of the patients were receiving a nbDMARD alone, 31.0% a TNFi with or without MTX and 1.4% tocilizumab. At week 52, structural remission (ΔmTSS/yr ≤0.5) was achieved in 49.7% of the patients, functional remission (HAQ-DI ≤0.5) in 63.4% and LDA in 51.0%. Clinical responses at weeks 12 and 24 were significant independent predictors of CRRP. Cumulative disease activity during the first 12 weeks predicted CRRP with a C-statistic of 0.888. CONCLUSION Achieving structural remission, functional remission and LDA in clinical practice in EORA patients are realistic goals. Our results indicate significant benefits for a therapeutic strategy targeting LDA for EORA patients in clinical practice.

Activation of fibroblast-like synoviocytes derived from rheumatoid arthritis via lysophosphatidic acid-lysophosphatidic acid receptor 1 cascade.

IntroductionLysophosphatidic acid (LPA) is a bioactive lipid that binds to G protein-coupled receptors (LPA1-6). Recently, we reported that abrogation of LPA receptor 1 (LPA1) ameliorated murine collagen-induced arthritis, probably via inhibition of inflammatory cell migration, Th17 differentiation and osteoclastogenesis. In this study, we examined the importance of the LPA-LPA1 axis in cell proliferation, cytokine/chemokine production and lymphocyte transmigration in fibroblast-like synoviocytes (FLSs) obtained from the synovial tissues of rheumatoid arthritis (RA) patients.MethodsFLSs were prepared from synovial tissues of RA patients. Expression of LPA1-6 was examined by quantitative real-time RT-PCR. Cell surface LPA1 expression was analyzed by flow cytometry. Cell proliferation was analyzed using a cell-counting kit. Production of interleukin 6 (IL-6), vascular endothelial growth factor (VEGF), chemokine?(C-C motif) ligand 2 (CCL2), metalloproteinase 3 (MMP-3) and chemokine (C-X-C motif) ligand 12 (CXCL12) was measured by enzyme-linked immunosorbent assay. Pseudoemperipolesis was evaluated using a coculture of RA FLSs and T or B cells. Cell motility was examined by scrape motility assay. Expression of adhesion molecules was determined by flow cytometry.ResultsThe expression of LPA1 mRNA and cell surface LPA1 was higher in RA FLSs than in FLSs from osteoarthritis tissue. Stimulation with LPA enhanced the proliferation of RA FLSs and the production of IL-6, VEGF, CCL2 and MMP-3 by FLSs, which were suppressed by an LPA1 inhibitor (LA-01). Ki16425, another LPA1 antagonist, also suppressed IL-6 production by LPA-stimulated RA FLSs. However, the production of CXCL12 was not altered by stimulation with LPA. LPA induced the pseudoemperipolesis of T and B cells cocultured with RA FLSs, which was suppressed by LPA1 inhibition. In addition, LPA enhanced the migration of RA FLSs and expression of vascular cell adhesion molecule and intercellular adhesion molecule on RA FLSs, which were also inhibited by an LPA1 antagonist.ConclusionsCollectively, these results indicate that LPA-LPA1 signaling contributes to the activation of RA FLSs.

Abrogation of CC chemokine receptor 9 ameliorates collagen-induced arthritis of mice

IntroductionBiological drugs are effective in patients with rheumatoid arthritis (RA), but increase severe infections. The CC chemokine receptor (CCR) 9 antagonist was effective for Crohn’s disease without critical adverse effects including infections in clinical trials. The present study was carried out to explore the pathogenic roles of chemokine (C-C motif) ligand (CCL) 25 and its receptor, CCR9, in autoimmune arthritis and to study if the CCR9 antagonist could be a new treatment for RA.MethodsCCL25 and CCR9 expression was examined with immunohistochemistry and Western blotting. Concentration of interleukin (IL)-6, matrix metalloproteinase (MMP)-3 and tumor necrosis factor (TNF)-α was measured with enzyme-linked immunosorbent assays. Effects of abrogating CCR9 on collagen-induced arthritis (CIA) was evaluated using CCR9-deficient mice or the CCR9 antagonist, CCX8037. Fluorescence labeled-CD11b+ splenocytes from CIA mice were transferred to recipient CIA mice and those infiltrating into the synovial tissues of the recipient mice were counted.ResultsCCL25 and CCR9 proteins were found in the RA synovial tissues. CCR9 was expressed on macrophages, fibroblast-like synoviocytes (FLS) and dendritic cells in the synovial tissues. Stimulation with CCL25 increased IL-6 and MMP-3 production from RA FLS, and IL-6 and TNF-α production from peripheral blood monocytes. CIA was suppressed in CCR9-deficient mice. CCX8037 also inhibited CIA and the migration of transferred CD11b+ splenocytes into the synovial tissues.ConclusionsThe interaction between CCL25 and CCR9 may play important roles in cell infiltration into the RA synovial tissues and inflammatory mediator production. Blocking CCL25 or CCR9 may represent a novel safe therapy for RA.

High prevalence of cardiovascular comorbidities in patients with rheumatoid arthritis from a population-based cross-sectional study of a Japanese health insurance database

Abstract Objective: To reveal any association between rheumatoid arthritis (RA) and cardiovascular comorbidities using a Japanese health insurance database. Method: This population-based cross-sectional study was conducted using health insurance data provided by the Japan Medical Data Center Co., Ltd. We identified 2762 RA subjects having RA diagnostic codes (ICD10 codes; M05, M060, M062–63, M068–069) with at least two physician visits more than two months apart between June 2011 and May 2012 (RA group, n = 2762). We selected age- (±5 years), sex-, and study period-matched non-RA subjects (non-RA group, n = 27,620). We compared the prevalence of cardiovascular and related comorbidities (ischemic heart diseases [IHD], cerebral infarction, hypertension [HT], dyslipidemia [DL], and diabetes mellitus [DM]) between these groups and investigated the association between RA and cardiovascular comorbidities using a conditional logistic regression analysis. Results: The prevalence of all the investigated comorbidities in the RA group was significantly higher compared to the non-RA group. Odds ratios [95% confidence interval] of RA for IHD and cerebral infarction were 2.0 [1.5–2.5] and 3.1 [2.2–4.2] respectively, after adjusting for HT, DL, and DM. Conclusions: This study revealed for the first time in the Japanese population that RA was significantly associated with cardiovascular comorbidities.

Myelitis and optic neuritis induced by a long course of etanercept in a patient with rheumatoid arthritis

A 64-year-old woman presented with an acute onset of myelitis and optic neuritis after 47 months of etanercept use for rheumatoid arthritis. Etanercept was discontinued and pulse methylprednisolone therapy (1000 mg/day for 3 days) was started, followed by a quick and complete resolution. Demyelination associated with antitumor necrosis factor agents, reported to develop mostly from 1 week to 12 months after the initiation of the agents, could develop after a few years and thus warrants vigilant monitoring.

CCL18 Activates Fibroblast-like Synoviocytes in Patients with Rheumatoid Arthritis

To the Editor: Fibroblast-like synoviocytes (FLS) proliferate in the synovial tissue of patients with rheumatoid arthritis (RA), and contribute to chronic inflammation and the destruction of articular cartilage due to the production of a variety of cytokines, chemokines, and matrix metalloproteinases (MMP)1. The expression of CC chemokine ligand 18 (CCL18) was shown to be increased in the RA synovium2,3; however, the pathogenic role of CCL18 remains unclear. In this study, we investigated the expression of a recently identified receptor for CCL18, phosphatidylinositol transfer membrane-associated phosphatidylinositol transfer protein 3 (PITPNM3)4 in the RA synovium, and the stimulatory effects of CCL18 on FLS. Synovial tissue samples were obtained from patients with RA (n = 4) and osteoarthritis (OA) (n = 4) undergoing joint replacement surgery. RA patients were a median 65 years old (range 48–85 yrs), with median disease duration 9 years (range 2.5–30 yrs) and median C-reactive protein level 1.23 mg/dl (range 0.68–2.85). All RA patients were positive for rheumatoid factor and anticitrullinated protein antibodies. All subjects provided informed consent. The experimental protocol was approved in advance by the Ethics Committee of Tokyo Medical and Dental University. CCL18-positive cells were observed in the synovial lining, sublining, and perivascular regions of the RA synovium (Figure 1A). CCL18 expression was minimal in the OA synovium (Figure 1C). Western blotting analysis showed that CCL18 expression was significantly higher in the RA synovium than in the OA synovium (Figure 1E, 1F). Double-immunofluorescence staining revealed that most CD68-positive macrophages expressed CCL18 (Figures 1G–1I), and von Willebrand factor (vWF)-positive vascular endothelial cells were also … Address correspondence to Dr. T. Nanki, Department of Medicine and Rheumatology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo 113-8519, Japan. E-mail: nanki.rheu{at}tmd.ac.jp

Achieving simplified disease activity index remission in patients with active rheumatoid arthritis is associated with subsequent good functional and structural outcomes in a real-world clinical setting under a treat-to-target strategy.

Abstract Objective: To verify predictive validity of simplified disease activity index (SDAI) remission for subsequent functional and structural outcomes in real-world clinical settings under a treat-to-target strategy (T2T). Methods: In this multicenter, prospective cohort study, T2T was implemented in rheumatoid arthritis (RA) patients with moderate-to-high disease activity. SDAI or clinical disease activity index (CDAI) was assessed every 12 weeks, and treatment was adjusted to achieve clinical remission or low disease activity (LDA). Multivariate logistic regression models were used to examine the associations of SDAI remission (≤3.3) at week 24 with the health assessment questionnaire-disability index (HAQ-DI) ≤ 0.5 or with the delta van der Heijde-modified total Sharp score (ΔvdH-mTSS) <smallest detectable change (SDC) at week 72. Results: Of 318 patients enrolled, 271 completed the follow-up for 72 weeks and were subjects of the analyses. Factors [odds ratio (95% confidence interval)] significantly associated with the HAQ-DI ≤0.5 were SDAI remission at week 24 [2.99 (1.42–6.28), p = 0.004], baseline HAQ-DI [0.28 (0.18–0.45), p = 1.3 × 10−7], and baseline vdH-mTSS [0.986 (0.976–0.996), p = 0.009]. A factor associated with ΔvdH-mTSS < SDC was SDAI remission at week 24 [3.53 (1.62–7.71), p = 0.002]. Conclusion: Predictive validity of SDAI remission for good outcomes was verified in a T2T-implementing cohort in the current clinical settings.