Interleukin-17 gene expression in patients with rheumatoid arthritis

Interleukin-17 is a proinflammatory cytokine. Recent animal studies have shown that IL-17 plays a role in the initiation and progression of arthritis. However, whether IL-17 has a prominent role in human rheumatoid arthritis (RA) or not remains unclear. Here we investigated the role of IL-17 in patients with RA. cDNA was prepared from knee joint synovial tissues of RA (n = 11) and osteoarthritic (OA, n = 10) patients and PBMC of RA (n = 52) and healthy subjects (n = 34). IL-17 gene expression level was measured by real-time PCR, and was compared with various clinical parameters. IL-17 gene expression in synovial tissues of RA was similar to that in OA. IL-17 gene expression level in PBMC of RA patients was significantly higher than in the control. The response (changes in DAS) to two-week treatment with anti-TNF-α blockers (infliximab or etanercept) did not correlate with changes in IL-17 gene expression levels. The IL-17/TNF-α gene expression ratio at baseline (before treatment) tended to be lower in responders to the treatment. Expression of IL-17 gene in PBMC may be associated with the inflammatory process of RA. IL-17/TNF-α expression ratio is a potentially suitable marker of response to anti-TNF-α therapy.     

The levels of leukemia inhibitory factor in synovial tissues of patients with rheumatoid arthritis: inflammation and other proinflammatory cytokines

Abstract

To clarify the effect of leukemia inhibitory factor (LIF) on the destruction of rheumatoid arthritis (RA) joints, we investigated the production of LIF and the expression of LIF mRNA in synovial tissues from patients with RA and osteoarthritis (OA). Synovial fluids from RA were used to measure the LIF concentrations using enzyme-linked immunosorbent assay (ELISA). Immunohistochemistory and RT-PCR were used to examine the expression of LIF by synovial cells. LIF mRNA was detected in all cases in RA synovial cells. Although LIF protein was detected only in 20 cases (19%) in RA synovial fluids, LIF concentration in the synovial fluids significantly correlated with the peripheral leukocyte count (P < 0.001) and C-reactive protein (CRP) (P < 0.01). Moreover, levels of IL-1β, IL-6, and IL-8, but not TNF-α, were significantly correlated with LIF in the RA synovial fluids. LIF production was promoted by IL-1β and TNF-α stimulation; in contrast, IL-1 ra and IL-4 were found to markedly decrease LIF production by cultured synovial cells. LIF appeared to be a cytokine produced by RA synovium leading to a proinflammatory secretion profile. Moreover, IL-4 and IL-1 ra may represent attenuated activity for reducing the effect of the destruction of joints by LIF.     

Synovial proinflammatory cytokines and their correlation with matrix metalloproteinase-3 expression in Behçet’s disease. Does interleukin-1β play a major role in Behçet’s synovitis?

The objective of this study has been the well established fact that proinflammatory cytokines and metalloproteinases play a crucial role in the pathogenesis of chronic arthritis as well as the development of pannus, with the eventual erosive changes. Among the proinflammatory cytokines, interleukin-18 (IL-18) has been shown to contribute to the pathogenesis of chronic synovitis by increasing the secretion of interleukin-1beta (IL-1β) and the tumor necrosis factor-alpha (TNF-α) and also stimulating angiogenesis. The aim of this study is to investigate the synovial IL-18, IL-1β, TNF-α and matrix metalloproteinase-3 (MMP-3) levels in patients with Behçet’s disease (BD), and compare them with the levels of patients with rheumatoid arthritis (RA) and osteoarthritis (OA). 30 patients with BD, 20 with RA, and 20 with OA were included in the study. The synovial levels of IL-18, IL-1β, TNF-α and MMP-3 were detected using the two-step sandwich ELISA method. The synovial IL-18, TNF-α and MMP-3 levels were significantly higher in RA patients than patients with BD (P=0.004, 0.019, 0.025, respectively) and with OA (P=0.004, 0.045, 0.032, respectively). There were no differences, with respect to the cytokine levels, when patients with BD were compared with those with OA. Patients with RA and BD had higher IL-1β levels than patients with OA (P=0.017, 0.013, respectively). However, no such difference was found for IL-1β between BD and RA patients. Among patients with RA, positive correlations were found between TNF-α and MMP-3 (r=0.683, P=0.001). Our results showed that MMP-3 and proinflammatory cytokines, except IL-1β, were expressed in relatively small quantities in Behçet’s synovitis. Detection of the lower levels of these cytokines and metalloproteinases might explain the non-erosive character of Behçet’s arthritis. We suggest that IL-1β may be involved in the pathogenesis of Behçet’s synovitis.     

Expression of membrane-type matrix metalloproteinases in synovial tissue from patients with rheumatoid arthritis or osteoarthritis

We investigated the expression of membrane-type matrix metalloproteinase (MT-MMP) and matrix metalloproteinase (MMP) mRNAs in synovial tissue from patients with rheumatoid arthritis (RA, n = 5) or osteoarthritis (OA, n = 5) by Northern blot analysis. Northern analysis demonstrated strong expression of MT1-MMP, MT3-MMP, MMP-1, and MMP-3 and weak expression of MT2-MMP and MMP-8 in synovial tissue from patients with RA or OA. MT4-MMP was not detected. No significant difference was shown in the expression of MT-MMP mRNAs between RA and OA. Synovial tissue of RA or OA patients expressed MT-MMPs as well as MMPs. These results indicate that, in addition to MMPs, MT1-MMP, MT3-MMP, and probably MT2-MMP may play a role in the degradation of bone and cartilage matrix in RA and OA. Such information may provide a clue to the development of a novel therapeutic approach targeted on the prevention of joint destruction. Received: April 30, 2000 / Accepted: September 19, 2000     

Regenerating gene (REG) 1 alpha promotes pannus progression in patients with rheumatoid arthritis

Abstract

Introduction A protein analysis using mass spectrometry revealed the existence of serum proteins with significant quantitative changes after the administration of infliximab. Among these proteins, regenerating gene (REG) 1α appears to be related to the pathogenesis of rheumatoid arthritis (RA). Therefore, the present study was conducted to examine the mechanism of REG1α in RA disease progression.

Methods Serum samples were collected from RA patients and normal healthy controls. REG1α expression was evaluated by ELISA, RT-PCR, and indirect immunofluorescence microscopy. The functions of REG1α on synovial fibroblasts with regard to apoptosis, receptor activator of NF-κB ligand (RANKL) expression, and cellar proliferation were evaluated using siRNA to inhibit the intrinsic REG1α mRNA expression.

Results The serum concentrations of REG1α in RA patients were higher than in normal healthy controls. The high expression of REG1α was also observed in the synovial tissue of RA patients compared to those of osteoarthropathy patients. In addition, tumor necrosis factor-α (TNF-α) upregulated REG1α expression in the synovial fibroblasts cell line (MH7A). Inhibition of REG1α expression suppressed the induction of RANKL expression by TNF-α. Furthermore, exogenous recombinant REG1α protein inhibited apoptosis and promoted cell proliferation in MH7A cells. These effects were abolished in the REG1α-siRNA MH7A cells.

Conclusion The present data suggest that TNF-α induces aberrant REG1α expression and that REG1α plays an important role in aberrant cell proliferation and RANKL expression of synovial fibroblasts, ultimately resulting in pannus formation. Restoration of normal physiological REG1α expression may contribute to disease amelioration.     

Serum and synovial fluid interleukin-17 concentrations in rheumatoid arthritis patients: Relation to disease activity,radiographic severity and power Doppler ultrasound

Aim of the workTo investigate serum and synovial fluid levels of IL-17 in rheumatoid arthritis (RA) patients, and its correlation with disease activity and severity.Patients and methods20 RA patients together with 20 primary knee osteoarthritis (KOA) patients and 15 healthy individuals matched for age and sex as control groups were enrolled in this study. Both RA and KOA patients presented with knee effusion. Paired samples of serum and synovial fluid (SF) were collected from RA, OA patients and serum samples from the healthy individuals. RA disease activity was assessed using DAS-28 score and power Doppler ultrasound (PDUS) according to the European League against Rheumatism (EULAR). Radiographic damage was evaluated according to Larsen score.ResultsSerum levels of IL-17 were significantly elevated in RA patients compared to controls (p < 0.001). Also, SF of IL-17 was significantly higher in RA patients compared to OA patients (p < 0.001). In addition, synovial level of IL-17 was significantly higher in RA patient compared to their serum level (p < 0.001). Regarding disease activity grading among RA patients, significant differences (p < 0.05) in mean serum and synovial IL-17 levels were reported being higher in severe active disease. Positive correlations of serum and SF IL 17 levels with PDUS findings and Larsen score were reported.ConclusionSerum and synovial IL-17 levels were significantly elevated in RA patients which clarifies its possible role in RA pathogenesis and correlates positively with disease activity parameters, PDUS findings and Larsen score. Thus targeting IL-17 may provide a promising role in suppressing RA.     

Application of a new immunohistology scoring system (IH score): Analysis of TNF-α in synovium related to disease activity score in infliximab-treated patients with rheumatoid arthritis

Abstract

Objectives. This study aimed to analyze the relationship between the expression of tumor necrosis factor alpha (TNF-α) or interleukin-6 (IL-6) in synovium and the disease activity score (DAS) 28 (C-reactive protein, CRP) in treatment of infliximab for rheumatoid arthritis (RA).

Methods. Synovial tissues were obtained from 16 infliximab-treated patients and assessed for TNF-α and IL-6 with a new immunohistology (IH) scoring system. The validation of IH score was performed and applied for the analysis of correlation between synovial TNF-α or IL-6 and DAS28 (CRP) in addition to Rooney score.

Results. The IH score had high internal validity; the IH score of TNF-α strongly correlated with serum CRP and matrix metalloprotease-3 (MMP-3), as well as DAS28 (CRP) and the Rooney score. IL-6 did not correlate with DAS28 (CRP).

Conclusions. This study indicates that the IH score is useful as a new procedure to assess the cytokine expression easily and TNF-α in synovium correlates with disease activity in patients with RA treated with infliximab.     

Relative expression and correlation of tumor necrosis factor-α, interferon-γ, and interleukin-17 in the rheumatoid synovium

Although tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), and interleukin-17 (IL-17) play important roles in RA, their relative expression and possible correlation in synovial tissues are not well understood. In this study, mRNA expression levels of IFN-γ, IL-17, and TNF-α were investigated in individual patients with RA and the correlations between pairs of these three pro-inflammatory cytokines were analyzed. Synovial tissues were obtained during arthroplasties from 24 joints of 24 RA patients. After harvesting synovial tissues, total RNA was isolated then quantitative real-time polymerase chain reaction (qRT-PCR) for IFN-γ, IL-17, and TNF-α was performed. Correlation of expression levels between them was also analyzed. Expression levels of TNF-α, IFN-γ, and IL-17 in patients receiving TNF inhibitors (TNFi) and those treated with conventional synthetic disease-modifying antirheumatic drugs (csDMARDs) alone were also compared between groups. Based on relative expression levels of the three pro-inflammatory cytokines, patients were classified into three major types; an IFN-γ plus TNF-α-dominant type, an IL-17-dominant type, and the other type. TNF-α expression levels were correlated with IFN-γ. In addition, there was a negative correlation between TNF-α and IL-17, and IFN-γ and IL-17. Median relative expression levels of TNF-α have no significant difference between the TNFi and the csDMARDs groups. In the rheumatoid synovial tissues, expression levels of TNF-α were modulated in parallel with IFN-γ, and TNF-α and IL-17, or IFN-γ and IL-17 did not co-express at high levels. This characteristic expression pattern of the three pro-inflammatory cytokines may be clinically useful information in the current cytokine-targeted treatment with biological DMARDs for RA.     

Tumor necrosis factor-α inhibits chondrogenic differentiation of synovial fibroblasts through p38 mitogen activating protein kinase pathways

Abstract

We previously reported that synovial fibroblast-like cells (SFs) can be differentiated into chondrocytes through activin receptor-like kinase (ALK) 3 activation. The aim of this study was to clarify the effect and signaling pathways of tumor necrosis factor (TNF)-α on the chondrogenic differentiation of SFs. Primary SFs from patients with rheumatoid arthritis (RA) were treated with recombinant human bone morphogenetic protein-2 or transduced with a constitutively active mutant of the ALK3 gene (ALK3^CA) with or without TNF-α, and then cultured in pellets. Expression of chondrocyte-specific genes was analyzed by real-time polymerase chain reaction or by histological analysis. Inhibitors of mitogen-activating protein kinase (MAPK) pathways or adenovirus vectors carrying a dominant-negative mutant of the IκB kinase 2 gene (AxIKK2^DN) were used to analyze the signaling pathways of TNF-α. Expression of chondrocyte-specific genes was induced in SFs either by rhBMP-2 treatment or by ALK3^CA transduction, which was strongly suppressed by TNF-α treatment. TNF-α markedly increased the p38 MAPK pathways in SFs, and inhibition of p38 MAPK activation partially restored the inhibitory effect of TNF-α on the chondrogenic differentiation of SFs. Combination therapy BMP-2 and anti-TNF-α agents especially targeting p38 MAPK might be a good approach to stimulating neochondrogenesis in the damaged joints in RA.     

IL-11 facilitates a novel connection between RA joint fibroblasts and endothelial cells

IL-11 has been detected in inflamed joints; however, its role in the pathogenesis of arthritis is not yet clear. Studies were conducted to characterize the expression and functional significance of IL-11 and IL-11Rα in rheumatoid arthritis (RA). IL-11 levels were elevated in RA synovial fluid (SF) compared to osteoarthritis (OA) SF and plasma from RA, OA and normal individuals (NLs). Morphologic studies established that IL-11 was detected in lining fibroblasts and macrophages in addition to sublining endothelial cells and macrophages at higher levels in RA compared to NL synovial tissues. Since IL-11Rα was exclusively expressed in RA fibroblasts and endothelial cells, macrophages were not involved in IL-11 effector function. Ligation of IL-11 to IL-11Rα strongly provoked fibroblast infiltration into RA joint, while cell proliferation was unaffected by this process. Secretion of IL-8 and VEGF from IL-11 activated RA fibroblasts was responsible for the indirect effect of IL-11 on endothelial cell transmigration and tube formation. Moreover, IL-11 blockade impaired RA SF capacity to elicit endothelial cell transmigration and tube formation. We conclude that IL-11 binding to endothelial IL-11Rα can directly induce RA angiogenesis. In addition, secretion of proangiogenic factors from migrating fibroblasts potentiated by IL-11 can indirectly contribute to RA neovascularization.     

The levels of leukemia inhibitory factor in synovial tissues of patients with rheumatoid arthritis: inflammation and other proinflammatory cytokines

 To clarify the effect of leukemia inhibitory factor (LIF) on the destruction of rheumatoid arthritis (RA) joints, we investigated the production of LIF and the expression of LIF mRNA in synovial tissues from patients with RA and osteoarthritis (OA). Synovial fluids from RA were used to measure the LIF concentrations using enzyme-linked immunosorbent assay (ELISA). Immunohistochemistory and RT-PCR were used to examine the expression of LIF by synovial cells. LIF mRNA was detected in all cases in RA synovial cells. Although LIF protein was detected only in 20 cases (19%) in RA synovial fluids, LIF concentration in the synovial fluids significantly correlated with the peripheral leukocyte count (P < 0.001) and C-reactive protein (CRP) (P < 0.01). Moreover, levels of IL-1β, IL-6, and IL-8, but not TNF-α, were significantly correlated with LIF in the RA synovial fluids. LIF production was promoted by IL-1β and TNF-α stimulation; in contrast, IL-1 ra and IL-4 were found to markedly decrease LIF production by cultured synovial cells. LIF appeared to be a cytokine produced by RA synovium leading to a proinflammatory secretion profile. Moreover, IL-4 and IL-1 ra may represent attenuated activity for reducing the effect of the destruction of joints by LIF. Received: February 12, 2002 / Accepted: September 6, 2002     

Analysis of vascular gene expression in arthritic synovium by laser‐mediated microdissection

Objective

In rheumatoid arthritis (RA), formation of new blood vessels is necessary to meet the nutritional and oxygen requirements of actively proliferating synovial tissue. The aim of this study was to analyze the specific synovial vascular expression profiles of several angiogenesis‐related genes as well as CD82 in RA compared with osteoarthritis (OA), using laser‐mediated microdissection (LMM).

Methods

LMM and subsequent real‐time polymerase chain reaction were used in combination with immunohistochemical analysis for area‐specific analysis of messenger RNA (mRNA) and protein expression of vascular endothelial growth factor (VEGF), VEGF receptor 1 (VEGFR‐1), VEGFR‐2, hypoxia‐inducible factor 1α (HIF‐1α), HIF‐2α, platelet‐derived growth factor receptor α (PDGFRα), PDGFRβ, inhibitor of DNA binding/differentiation 2 (Id2), and CD82 in RA and OA synovial microvasculature and synovial lining.

Results

Expression of Id2 mRNA was significantly lower in RA synovial vessels compared with OA synovial vessels (P = 0.0011), whereas expression of VEGFR‐1 was significantly higher in RA (P = 0.0433). No differences were observed for the other parameters. At the protein level, no statistically significant differences were observed for any parameter, although Id2 levels were 2.5‐fold lower in RA (P = 0.0952). However, the number of synovial blood vessels and the number of VEGFR‐2–expressing blood vessels were significantly higher in RA compared with OA.

Conclusion

Our results underscore the importance of area‐specific gene expression analysis in studying the pathogenesis of RA and support LMM as a robust tool for this purpose. Of note, our results indicate that previously described differences between RA and OA in the expression of angiogenic molecules are attributable to higher total numbers of synovial and vascular cells expressing these molecules in RA rather than higher expression levels in the individual cells.

     

Regulatory effect of nicotine on collagen-induced arthritis and on the induction and function of in vitro-cultured Th17 cells

Abstract

Objectives. To determine the effect of nicotine stimulation on collagen-induced arthritis (CIA), especially on Th17 cells, and the influence of activated acetylcholine receptor signaling on the induction and function of in vitro-cultured Th17 cells.

Methods. Mice were divided into control and experimental (nicotine) group, and PBS or nicotine-PBS was orally administered from Day 21 to Day 28. Phenotypic changes in spleen CD4⁺ cells were measured by flow cytometry. α7nAChR expression in Th17 cells was detected using flow cytometry, western blotting and real-time PCR. Purified Th17 cells were further stimulated with nicotine. The cytometric bead array (CBA) assay was employed to measure TNF-α levels in mice serum and IL-17A levels in the supernatants of nicotine-treated cell cultures.

Results. Compared with their counterparts, mice receiving oral nicotine showed a delayed progress of arthritis and more attenuated signs of histological changes. Moreover, serum TNFα levels were lower in the nicotine-treated group. Spleen IL-17 level of nicotine-treated mice was lower than that of the control group, and the mRNA expression of pro-inflammatory cytokines (IL-17A and IL-6) in splenocytes were also lower than that of the control group. α7nAChR expression was detected on in vitro-cultured IL-17A⁺ cells. Cells treated with 10 ^{? 6} M nicotine expressed lower IL-17A levels. Similarly, supernatants from nicotine-treated cell cultures also showed lower IL-17A levels.

Conclusions. Nicotine stimulation attenuated signs and severity of arthritis in mice. Activation of nicotine acetylcholine receptors on in vitro-cultured Th17 cells decreased their pro-inflammatory function, which may play a potential role in alleviating arthritis in mice.     

Expression of matrix metalloproteinase 9 (96-kd gelatinase B) in human rheumatoid arthritis

Objective. To determine the expression of matrix metalloproteinase 9/gelatinase B (MMP-9) in synovial fluid (SF), plasma, and synovial tissue from individuals with rheumatoid arthritis (RA), inflammatory arthritis (IA), and osteoarthritis (OA), using specific monoclonal antibody reagents. Methods. Gelatinolytic activity in the SF and plasma of patients with RA, IA, and OA was assessed by gelatin zymography. A mouse monoclonal antiserum, 277.13, which selectively recognizes soluble latent forms of human MMP-9, was used to quantitate MMP-9 levels in patient synovial effusions, plasma, and synovial tissue with a capture sandwich enzyme-linked immunosorbent assay (ELISA). Fifty-one SF samples (31 RA, 9 OA, 11 IA) were analyzed. Immunolocalization of MMP-9 in RA, OA, and normal synovium was investigated using MMP-9–specific antisera. Results. MMP-9 antigen levels in synovial effusions were elevated 67-fold in RA samples compared with OA samples. In addition, although MMP-9 antigen levels in IA synovial effusions were 2.7-fold less than the values in RA samples, they were elevated 34-fold over the values in OA samples. These data indicate an association between increased MMP-9 levels and inflammatory arthritis. A predominant 92-kd gelatinolytic activity (specifically inhibited by EDTA) was evident in RA and IA samples, but no activity was observed in OA samples. Among 86 plasma samples (17 RA, 9 IA, 60 normal controls) analyzed for MMP-9 antigen levels by immunocapture ELISA, MMP-9 antigen levels were elevated 7-fold in RA plasma compared with normal plasma. RA synovial tissue extracts demonstrated elevated levels of MMP-9 antigen compared with OA synovial tissue. MMP-9 immunolocalization studies demonstrated expression in infiltrating leukocytes (neutrophils and macrophages), endothelial cells, and synovial fibroblasts in RA synovium. Conclusion. Latent MMP-9 and/or MMP-9–tissue inhibitor of metalloproteinases 1 (TIMP-1) complexes are elevated in RA and IA SF compared with OA SF. In addition, MMP-9 is increased in RA plasma versus normal control plasma. Synovial tissue levels of MMP-9 antigen are also elevated in RA versus OA. The tissue distribution of MMP-9 within RA synovium is localized to sites of inflammation comprising surface synovial lining cells, endothelium, and leukocytes. Taken together, these observations suggest that connective tissue turnover occurs as a result of excessive MMP activity over TIMP action in the invading pannus, periarticular tissue, or SF. Further studies such as those used in the present investigation will help elucidate the role of a number of different enzymes and inhibitors in the destructive arthropathies.     

类风湿关节炎患者程序化死亡基因5与肿瘤坏死因子-α的表达及其相关性分析

目的 检测类风湿关节炎(RA)及骨关节炎患者血清、滑液中程序化死亡基因(PDCD)5及肿瘤坏死因子(TNF)-α的表达水平,并分析PDCD5与TNF-α表达的相关性,初步探讨PDCD5在RA发病机制中的作用.方法 选取2009年12月至2010年8月50例患者(其中RA 26例,骨关节炎24例),采用酶联免疫吸附试验(ELISA)法检测血清、滑液中PDCD5及TNF-α的含量,统计学分析采用t检验及Pearson直线相关分析.结果 血清中,RA患者的PDCD5含量显著高于骨关节炎患者[(37±33)与(13±14) pg/ml,P＝0.02];滑液中,RA患者的PDCD5含量也显著高于骨关节炎患者[(37±26)与(11±7)pg/ml,P＜0.01].TNF-α在RA患者血清中的含量与骨关节炎患者比较差异无统计学意义(P=0.122),但其在RA患者滑液中的含量显著高于骨关节炎患者(P=0.037).PDCD5与TNF-α在RA及骨关节炎患者的血清中均呈负相关(r=-0.55,P=0.004;r=-0.51,P=0.012),PDCD5与TNF-α在RA患者的滑液中也呈负相关(r=-0.49,P=0.012),但在骨关节炎患者的滑液中无相关(r=-0.353,P=0.09).结论 PDCD5与TNF-α是RA重要的凋亡调控因子,在RA的发生发展过程中发挥重要作用.     

Dynamics of interleukin (IL)-18 in serum, synovial fluid and synovial membrane in the patients with rheumatoid arthritis]

OBJECTIVES: IL-18 is a novel cytokine that plays an important role in the Th1 response. The aim of this study is to investigate the dynamics of IL-18 in serum, synovial fluid and synovial membrane in the patients with rheumatoid arthritis. MATERIALS AND METHODS: The serum, synovial fluid and synovial membrane were obtained from RA patients at operation. The levels of IL-18 in the serum and synovial fluid were measured by ELISA. We then examined the expression of IL-18 in synovial tissues using anti-human IL-18 monoclonal antibody in immunohistochemical study. RESULTS: The levels of IL-18 in serum and synovial fluid in RA patients were 193.7 +/- 109.7 pg/ml and 258.8 +/- 238.0 pg/ml, respectively. Compared with OA patients and normal volunteers, the level of IL-18 in RA patients was higher in both serum and synovial fluid. (P < 0.05) In synovial membrane, the cells positive for anti IL-18 antibody were confirmed not only in RA (n = 26) but also in OA (n = 7) patients. The positive cells were the synovial lining cells, macrophages, fibroblasts and endothelial cells. However, a large number of positive cells were demonstrated in synovial tissues in RA compared with OA patients.