Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease caused by inflammatory cells. Various inflammatory cells involved in RA include fibroblast-like synoviocytes, macrophages, CD4⁺T-lymphocytes, B lymphocytes, osteoclasts and chondrocytes. The close interaction between various inflammatory cells leads to imbalance of immune response and disorder of the expression of mRNA in inflammatory cells. It helps to drive production of pro-inflammatory cytokines and stimulate specific antigen-specific T- and B-lymphocytes to produce autoantibodies which is an important pathogenic factor for RA. Competing endogenous RNA (ceRNA) can regulate the expression of mRNA by competitively binding to miRNA. The related ceRNA network is a new regulatory mechanism for RNA interaction. It has been found to be involved in the regulation of abnormal biological processes such as proliferation, apoptosis, invasion and release of inflammatory factors of RA inflammatory cells. Understanding the ceRNA network in 6 kinds of RA common inflammatory cells provides a new idea for further elucidating the pathogenesis of RA, and provides a theoretical basis for the discovery of new biomarkers and effective therapeutic targets.
Humans ; Arthritis, Rheumatoid/genetics* ; MicroRNAs/metabolism* ; Synoviocytes/pathology* ; Cytokines/metabolism* ; RNA, Messenger/metabolism* ; Fibroblasts/pathology* ; Cell Proliferation

OBJECTIVE: Rheumatoid arthritis (RA) progression is associated with the balance of T-regulatory (Treg) and T-helper 17 (Th17) cells, while the role of microRNAs (miRs) in regulating Treg/Th17 cell balance has not been clarified. This study aimed to assess whether moxibustion could regulate Treg/Th17 cell balance by modulating the miR-221/suppressor of cytokine signaling 3 (SOCS3) axis in the RA mouse model. METHODS: A mouse model of collagen-induced arthritis (CIA) was established in male DBA/1J mice. Twenty-two days after CIA induction, the mice received daily treatment with moxibustion for 12 times. Pathological scores were assessed according to the levels of synovial hyperplasia. The expression levels of cytokines interleukin (IL)-1β, IL-6, tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), IL-17 and IL-10 were analyzed in serum by enzyme-linked immunosorbent assay. The cluster of differentiation 4 (CD4⁺) splenocytes was analyzed by fluorescence-activated cell sorting. The expression levels of RA-related miRs and target genes were subsequently detected, and the target of miR-221 was confirmed by the dual-luciferase reporter assay. RESULTS: It was revealed that moxibustion treatment decreased the pathological scores and downregulated the expression levels of IL-1β, IL-6, TNF-α, IFN-γ and IL-17, while upregulated the expression level of IL-10. The Treg/Th17 cell balance was regulated by moxibustion treatment. The expression level of miR-221 was suppressed by moxibustion treatment. Furthermore, SOCS3 was found as the direct target of miR-221, which mediated the function of moxibustion by regulating the Treg/Th17 cell balance. CONCLUSION Moxibustion therapy regulated the Treg/Th17 cell balance by modulating the miR-221/SOCS3 axis in the RA mouse model.
Animals ; Arthritis, Experimental/therapy* ; Arthritis, Rheumatoid/therapy* ; Cytokines ; Disease Models, Animal ; Interleukin-10 ; Interleukin-17 ; Interleukin-6 ; Male ; Mice ; Mice, Inbred DBA ; MicroRNAs/genetics* ; Moxibustion ; T-Lymphocytes, Regulatory ; Th17 Cells/pathology* ; Tumor Necrosis Factor-alpha

The object of this review is to help readers to understand meta-analysis of genetic association study. Genetic association studies are a powerful approach to identify susceptibility genes for common diseases. However, the results of these studies are not consistently reproducible. In order to overcome the limitations of individual studies, larger sample sizes or meta-analysis is required. Meta-analysis is a statistical tool for combining results of different studies on the same topic, thus increasing statistical strength and precision. Meta-analysis of genetic association studies combines the results from independent studies, explores the sources of heterogeneity, and identifies subgroups associated with the factor of interest. Meta-analysis of genetic association studies is an effective tool for garnering a greater understanding of complex diseases and potentially provides new insights into gene-disease associations.
Arthritis, Rheumatoid/genetics/pathology ; Databases, Factual ; *Genetic Association Studies ; Genotype ; Humans ; Polymorphism, Single Nucleotide ; Receptors, Immunologic/genetics

Rheumatoid arthritis (RA) and osteoarthritis (OA), two common types of arthritis, affect the joints mainly by targeting the synovium and cartilage. Increasing evidence indicates that a significant network connects synovitis and cartilage destruction during the progression of arthritis. We recently demonstrated that hypoxia-inducible factor (HIF)-2alpha causes RA and OA by regulating the expression of catabolic factors in fibroblast-like synoviocytes (FLS) or chondrocytes. To address the reciprocal influences of HIF-2alpha on FLS and chondrocytes, we applied an in vitro co-culture system using a transwell apparatus. When co-cultured with HIF-2alpha-overexpressing chondrocytes, FLS exhibited increased expression of matrix metalloproteinases and inflammatory mediators, similar to the effects induced by tumor-necrosis factor (TNF)-alpha treatment of FLS. Moreover, chondrocytes co-cultured with HIF-2alpha-overexpressing FLS exhibited upregulation of Mmp3 and Mmp13, which is similar to the effects induced by interleukin (IL)-6 treatment of chondrocytes. We confirmed these differential HIF-2alpha-induced effects via distinct secretory mediators using Il6-knockout cells and a TNF-alpha-blocking antibody. The FLS-co-culture-induced gene expression changes in chondrocytes were significantly abrogated by IL-6 deficiency, whereas TNF-alpha neutralization blocked the alterations in gene expression associated with co-culture of FLS with chondrocytes. Our results further suggested that the observed changes might reflect the HIF-2alpha-induced upregulation of specific receptors for TNF-alpha (in FLS) and IL-6 (in chondrocytes). This study broadens our understanding of the possible regulatory mechanisms underlying the crosstalk between the synovium and cartilage in the presence of HIF-2alpha, and may suggest potential new anti-arthritis therapies.
Animals ; Arthritis/genetics/*immunology/pathology ; Arthritis, Rheumatoid/genetics/immunology/pathology ; Basic Helix-Loop-Helix Transcription Factors/genetics/*immunology ; Cells, Cultured ; Chondrocytes/immunology/metabolism/*pathology ; Coculture Techniques ; Fibroblasts/immunology/metabolism/*pathology ; Gene Expression Regulation ; Interleukin-6/genetics/*immunology ; Male ; Mice ; Mice, Inbred C57BL ; Osteoarthritis/genetics/immunology/pathology ; Synovial Membrane/immunology/metabolism/*pathology ; Tumor Necrosis Factor-alpha/genetics/*immunology ; Up-Regulation

Eupatilin is the main active component of DA-9601, an extract from Artemisia. Recently, eupatilin was reported to have anti-inflammatory properties. We investigated the anti-arthritic effect of eupatilin in a murine arthritis model and human rheumatoid synoviocytes. DA-9601 was injected into collagen-induced arthritis (CIA) mice. Arthritis score was regularly evaluated. Mouse monocytes were differentiated into osteoclasts when eupatilin was added simultaneously. Osteoclasts were stained with tartrate-resistant acid phosphatase and then manually counted. Rheumatoid synoviocytes were stimulated with TNF-alpha and then treated with eupatilin, and the levels of IL-6 and IL-1beta mRNA expression in synoviocytes were measured by RT-PCR. Intraperitoneal injection of DA-9601 reduced arthritis scores in CIA mice. TNF-alpha treatment of synoviocytes increased the expression of IL-6 and IL-1beta mRNAs, which was inhibited by eupatilin. Eupatilin decreased the number of osteoclasts in a concentration dependent manner. These findings, showing that eupatilin and DA-9601 inhibited the expression of inflammatory cytokines and the differentiation of osteoclasts, suggest that eupatilin and DA-9601 is a candidate anti-inflammatory agent.
Animals ; Anti-Inflammatory Agents/pharmacology/*therapeutic use ; Arthritis, Experimental/chemically induced/*drug therapy ; Arthritis, Rheumatoid/drug therapy/pathology ; Cell Differentiation/*drug effects ; Cells, Cultured ; Collagen Type II ; Cytokines/biosynthesis ; Disease Models, Animal ; Drugs, Chinese Herbal/therapeutic use ; Female ; Flavonoids/pharmacology/*therapeutic use ; Humans ; Inflammation/drug therapy/immunology ; Interleukin-1beta/genetics/metabolism ; Interleukin-6/genetics/metabolism ; Lymph Nodes/cytology ; Mice ; Mice, Inbred DBA ; Monocytes/cytology ; Osteoclasts/*cytology ; Plant Extracts/pharmacology ; RNA, Messenger/biosynthesis ; Synovial Membrane/cytology ; T-Lymphocytes, Regulatory/cytology/immunology ; Tumor Necrosis Factor-alpha/pharmacology

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by abnormal proliferation of synoviocytes, leukocyte infiltration, and angiogenesis. The endoplasmic reticulum (ER) is the site of biosynthesis for all secreted and membrane proteins. The accumulation of unfolded proteins in the ER leads to a condition known as ER stress. Failure of the ER's adaptive capacity results in abnormal activation of the unfolded protein response. Recently, we have demonstrated that ER stress-associated gene signatures are highly expressed in RA synovium and synovial cells. Mice with Grp78 haploinsufficiency exhibit the suppression of experimentally induced arthritis, suggesting that the ER chaperone GRP78 is crucial for RA pathogenesis. Moreover, increasing evidence has suggested that GRP78 participates in antibody generation, T cell proliferation, and pro-inflammatory cytokine production, and is therefore one of the potential therapeutic targets for RA. In this review, we discuss the putative, pathophysiological roles of ER stress and GRP78 in RA pathogenesis.
Animals ; Arthritis, Rheumatoid/genetics/*pathology ; Autoantibodies/immunology ; Cell Proliferation ; Cytokines/biosynthesis/immunology ; Endoplasmic Reticulum/immunology/pathology ; Endoplasmic Reticulum Stress/*immunology ; Haploinsufficiency/genetics ; Heat-Shock Proteins/*genetics/*immunology ; Humans ; Lymphocyte Activation ; Mice ; Neovascularization, Pathologic/genetics ; Protein Folding ; Synovial Membrane/cytology ; T-Lymphocytes/immunology ; Unfolded Protein Response/*immunology

Triptolide (TPT), an active compound extracted from Chinese herb Tripterygium wilfordii , has been used in therapy of rheumatoid arthritis (RA). In this study, after synovial fibroblasts from rheumatoid arthritis (RASFs) were treated with TPT, we investigated its effect on the differentiation of Th17 cells. Firstly, the mRNA level of cyclooxygenase (COX) wad detected by qRT-PCR and the protein level of prostaglandin E2 (PGE2) was tested by ELISA in RASFs treated with different concentrations (0, 10, 50, 100 nmol L-1 ) of TPT. Then after TPT pre-treated RASFs and RA CD4 + T cells wer e co-cultured for 3 days in the presence or absence of PGE2, IL-17 and IFN-gamma production in CD4 T cell subsets were detected by flow cytometry. The results showed TPT decreased the mRNA experssion of COX2 and the secretion of PGE2 in RASFs in a dose-dependent manner(P <0. 05). We further found that differentiation of Thl7 cells was downregulated in a dose-dependent manner, and exogenous PGE2 could reverse the inhibition of Th17 cell differentiation(P <0. 05). Taken together, our results demonstrated that TPT inhibited the mRNA level of COX2 and the secretion of PGE2 in RASFs, which partly led to impaired Th17 cell differentiation in vitro.
Arthritis, Rheumatoid ; drug therapy ; enzymology ; immunology ; Cell Differentiation ; drug effects ; Cell Line ; Cyclooxygenase 2 ; genetics ; metabolism ; Dinoprostone ; metabolism ; Diterpenes ; pharmacology ; Epoxy Compounds ; pharmacology ; Fibroblasts ; drug effects ; immunology ; Gene Expression Regulation, Enzymologic ; drug effects ; Humans ; Middle Aged ; Phenanthrenes ; pharmacology ; Synovial Fluid ; drug effects ; Th17 Cells ; drug effects ; pathology

Oxidative stress such as reactive oxygen species (ROS) within the inflamed joint have been indicated as being involved as inflammatory mediators in the induction of arthritis. Correlations between extracellular-superoxide dismutase (EC-SOD) and inflammatory arthritis have been shown in several animal models of RA. However, there is a question whether the over-expression of EC-SOD on arthritic joint also could suppress the progression of disease or not. In the present study, the effect on the synovial tissue of experimental arthritis was investigated using EC-SOD over-expressing transgenic mice. The over-expression of EC-SOD in joint tissue was confirmed by RT-PCR and immunohistochemistry. The degree of the inflammation in EC-SOD transgenic mice was suppressed in the collagen-induced arthritis model. In a cytokine assay, the production of pro-inflammatory cytokines such as, IL-1beta, TNFalpha, and matrix metalloproteinases (MMPs) was decreased in fibroblast-like synoviocyte (FLS) but not in peripheral blood. Histological examination also showed repressed cartilage destruction and bone in EC-SOD transgenic mice. In conclusion, these data suggest that the over-expression of EC-SOD in FLS contributes to the activation of FLS and protection from joint destruction by depressing the production of the pro-inflammatory cytokines and MMPs. These results provide EC-SOD transgenic mice with a useful animal model for inflammatory arthritis research.
Animals ; Arthritis, Experimental/blood/*enzymology/metabolism ; *Arthritis, Rheumatoid/enzymology/pathology ; Fibroblasts/metabolism ; Gene Expression Regulation ; Inflammation/pathology ; Interleukin-1beta/blood/metabolism ; Joints/enzymology/pathology ; Matrix Metalloproteinases/blood/metabolism ; Mice ; Mice, Transgenic ; Reactive Oxygen Species/metabolism ; *Superoxide Dismutase/genetics/metabolism ; Synovial Fluid/*enzymology ; Synovial Membrane/pathology

B cells play an important role in the pathogenesis of rheumatoid arthritis (RA). High levels of B cell activating factor (BAFF) are detected in autoimmune diseases. BAFF and BAFF receptor (BAFF-R) are expressed in B and T cells of RA synovium. The study was undertaken to identify the NF-kappaB signal pathway involved in the induction of BAFF-R in human B cells. Immunohistochemical staining of NF-kappaB p65, NF-kappaB p50, BAFF, and BAFF-R was performed on sections of synovium from severe and mild RA and osteoarthritis (OA) patients. Peripheral blood mononuclear cells (PBMCs) were isolated from control and RA patients and B cells were isolated from controls. BAFF-R was analyzed by flow cytometry, realtime PCR and confocal staining after treatment with NF-kappaB inhibitors. NF-kappaB p65, NF-kappaB p50, BAFF, and BAFF-R were highly expressed in severe RA synovium relative to mild RA synovium or OA synovium. BAFF-R expression was reduced by NF-kappaB inhibitors in PBMCs and B cells from normal controls. We also showed reduction in expression of BAFF-R via inhibition of the NF-kappaB pathway in PBMCs of RA patients. BAFF/BAFF-R signaling is an important mechanism of pathogenesis in RA and that BAFF-R reduction by NF-kappaB blocking therapy is another choice for controlling B cells in autoimmune diseases such as RA.
Arthritis, Rheumatoid/genetics/*metabolism/pathology/physiopathology ; B-Cell Activating Factor/genetics/metabolism ; B-Cell Activation Factor Receptor/genetics/*metabolism ; B-Lymphocytes/*drug effects/immunology/metabolism/pathology ; Cell Separation ; Cells, Cultured ; Disease Progression ; Enzyme Inhibitors/pharmacology ; Flow Cytometry ; Gene Expression Regulation/immunology ; Humans ; Immunohistochemistry ; NF-kappa B/*metabolism ; Signal Transduction/immunology ; Synovial Membrane/*pathology ; T-Lymphocytes/drug effects/immunology/metabolism/pathology ; Transcriptional Activation/drug effects

Inadequate apoptosis contributes to synovial hyperplasia in rheumatoid arthritis (RA). Recent study shows that low expression of Puma might be partially responsible for the decreased apoptosis of fibroblast-like synoviocytes (FLS). Slug, a highly conserved zinc finger transcriptional repressor, is known to antagonize apoptosis of hematopoietic progenitor cells by repressing Puma transactivation. In this study, we examined the expression and function of Slug in RA FLS. Slug mRNA expression was measured in the synovial tissue (ST) and FLS obtained from RA and osteoarthritis patients. Slug and Puma mRNA expression in FLS by apoptotic stimuli were measured by real-time PCR analysis. FLS were transfected with control siRNA or Slug siRNA. Apoptosis was quantified by trypan blue exclusion, DNA fragmentation and caspase-3 assay. RA ST expressed higher level of Slug mRNA compared with osteoarthritis ST. Slug was significantly induced by hydrogen peroxide (H2O2) but not by exogenous p53 in RA FLS. Puma induction by H2O2 stimulation was significantly higher in Slug siRNA-transfected FLS compared with control siRNA-transfected FLS. After H2O2 stimulation, viable cell number was significantly lower in Slug siRNA-transfected FLS compared with control siRNA-transfected FLS. Apoptosis enhancing effect of Slug siRNA was further confirmed by ELISA that detects cytoplasmic histone-associated DNA fragments and caspase-3 assay. These data demonstrate that Slug is overexpressed in RA ST and that suppression of Slug gene facilitates apoptosis of FLS by increasing Puma transactivation. Slug may therefore represent a potential therapeutic target in RA.
Apoptosis/*drug effects/genetics ; Apoptosis Regulatory Proteins/*genetics/metabolism ; Arthritis, Rheumatoid/genetics/metabolism/*pathology ; Cells, Cultured ; Drug Evaluation, Preclinical ; Fibroblasts/drug effects/metabolism/pathology ; Humans ; Hydrogen Peroxide/*pharmacology ; Proto-Oncogene Proteins/*genetics/metabolism ; RNA, Small Interfering/*pharmacology ; Synovial Membrane/cytology/drug effects/metabolism/*pathology ; Transcription Factors/*antagonists & inhibitors/genetics ; Transcriptional Activation/drug effects ; Transfection