Interleukin (IL)-36 is a family of cytokines that belongs to the larger IL-1 superfamily. IL-36 agonist/antagonist binds to the interleukin-36 receptor involving in physiological inflammation regulation and pathogenesis of many inflammatory diseases. In inflammatory joint diseases, the expression of IL-36 changes, and some studies have initially explored the role of IL-36 in these diseases. In psoriatic arthritis, IL-36 signal mediates plasma cell and fibroblast-like synoviocyte crosstalk presenting IL-36 agonist/antagonist imbalance. In rheumatoid arthritis, IL-36 agonists induce fibroblast-like synoviocyte to produce pro-inflammatory factors, while IL-36 antagonist deficiency leads to lesion progression. In osteoarthritis, IL-36 agonists induce chondrocytes to produce catabolic enzymes and pro-inflammatory factors. This article reviews the expression and function of IL-36 in different inflammatory joint diseases to provide a reference for revealing their pathogenic mechanisms and discovering therapeutic targets.
Humans ; Interleukins ; Arthritis, Rheumatoid ; Osteoarthritis/pathology* ; Arthritis, Psoriatic/metabolism* ; Cytokines

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

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease. It is known that aucubin (AU) exerts anti-inflammatory activity, but its effects and mechanisms in RA are unclear. This study investigated the anti-inflammatory effects and mechanisms of AU in vivo and in vitro. Human fibroblast-like synoviocyte cells from patients with RA (HFLS-RA), RAW264.7 cells, and MC3T3-E1 cells were used to evaluate the effects of AU on migration, invasion, apoptosis, osteoclast differentiation and production. Immunofluorescence was used to observe nuclear translocation of nuclear factor (NF)-κB, the double luciferase reporter gene method was used to observe NF-κB-p65 activity in AU-treated MC3T3-E1 cells. RT-qPCR was used to measure expression of bone metabolism and inflammation-related genes, and western blot was used to measure bone metabolism and NF-κB protein expression levels. Collagen-induced arthritis (CIA) rat model was used for pharmacodynamics study. Arthritis indexes were measured in the ankle and knee, histological staining and Micro-computed tomography were performed on the ankle joints. Also, inflammatory factor gene expression and the levels of NF-κB-related proteins were detected as in vitro. AU effectively inhibited HFLS-RA cell migration and invasion, promoted apoptosis, and inhibited RAW264.7 cell differentiation into osteoclasts, as well as inhibited NF-κB-p65 activity in MC3T3-E1 cells. Notably, AU significantly reduced the gene expression levels of three cell-related inflammatory factors and bone metabolism factors, effectively inhibited the expression of p-Iκκα β, p-IκBα, and p-p65 proteins. In vivo, AU relieved joint inflammation, reduced related inflammatory factors, and inhibited NF-κB signaling. It could be used to treat RA-related synovial inflammation and bone destruction through the NF-κB pathway.
Animals ; Anti-Inflammatory Agents/therapeutic use* ; Arthritis, Experimental ; Arthritis, Rheumatoid/drug therapy* ; Cells, Cultured ; Humans ; Inflammation/pathology* ; Iridoid Glucosides ; NF-kappa B/metabolism* ; Rats ; X-Ray Microtomography

OBJECTIVE: To investigate the therapeutic mechanism of emodin in the treatment of rheumatoid arthritis (RA) using a network pharmacology-based method and validate this mechanism in a fibroblast-like synovial cell line. METHODS: The PubChem, Targetnet, SwissTargetPrediction, Genecards, OMIM, and DisGeNET databases were searched to obtain emodin targets and RA-related genes. A protein-protein interaction (PPI) network was constructed, and GO and KEGG pathway enrichment analyses were carried out to analyze the intersection genes. AutoDock4.2.6 software was used to simulate molecular docking between emodin and its candidate targets. In a cultured fibroblast-like synovial cell line (MH7A), the effects of different concentrations of emodin on proliferation of tumor necrosis factor-α (TNF-α)-induced cells were investigated using CCK-8 assay, cell scratch experiment and flow cytometry; the changes in the expressions of nuclear factor-κB (NF-κB) pathway proteins were detected using Western blotting, and the mRNA expressions of the hub genes were examined with RT-qPCR. RESULTS: We identified 32 intersection genes of emodin and RA, and the key targets including CAPS3, ESR1, and MAPK14 involved mainly the NF-κB signaling pathway. Cell scratch experiment and flow cytometry demonstrated a strong inhibitory effect of emodin on MH7A cell proliferation. Treatment with TNF-α significantly increased the cellular expressions of the NF-κB pathway proteins, which were obviously lowered by treatment with 80 μmol/L emodin. The results of RT-qPCR showed that TNF-α treatment obviously up-regulated the expressions of the hub genes COX2 and P38MAPK, and emodin treatment significantly down-regulated the expressions of MAPK and PTGS2 and up-regulated the expression of CASP3. CONCLUSION The therapeutic effect of emodin on RA is mediated mainly through regulation of cell proliferation, apoptosis, and the NF-κB pathway.
Arthritis, Rheumatoid/pathology* ; Emodin/pharmacology* ; Humans ; Molecular Docking Simulation ; NF-kappa B/metabolism* ; Network Pharmacology ; Tumor Necrosis Factor-alpha/pharmacology*

OBJECTIVE: To investigate the effect of triptolide (TPL) on inflammatory response and migration of fibroblast like synovial cells (FLS) in rheumatoid arthritis (RA-FLS) and the mechanism of circular noncoding RNA (circRNA) 0003353 for mediating this effect. METHODS: We collected peripheral blood mononuclear cells (PBMCs) and serum samples from 50 hospitalized RA patients and 30 healthy individuals for detecting the expression of circRNA 0003353, immune and inflammatory indexes (ESR, CRP, RF, anti-CCP, IgA, IgG, IgM, C3, and C4) and DAS28 score. Cultured RA-FLS was treated with 10 ng/mL TPL and transfected with a circRNA 0003353 overexpression plasmid, and cell counting kit-8 (CCK-8) assay and Transwell assay were used to detect the changes in the viability and migration of the cells. Enzyme-linked immunosorbent assay (ELISA) was used to examine the cytokines IL-4, IL-6, and IL-17, and real-time fluorescence quantitative PCR (RT-qPCR) was performed to detect the expression of circRNA 003353; Western blotting was used to detect the expressions of p-JAK2, pSTAT3, JAK2 and STAT3 proteins in the treated cells. RESULTS: The expression of circRNA 0003353 was significantly increased in PBMCs from RA patients and showed a good performance in assisting the diagnosis of RA (AUC=90.5%, P < 0.001, 95% CI: 0.83-0.98). CircRNA 0003353 expression was positively correlated with ESR, RF and DAS28 (P < 0.05). Treatment with TPL significantly decreased the expression of circRNA 0003353, suppressed the viability and migration ability, decreased the expressions of IL-6 and IL-17, and increased the expression IL-4 in cultured RA-FLS in a time-dependent manner (P < 0.01). TNF-α stimulation of RA-FLS significantly increased the ratios of p-JAK2/JAK2 and p-STAT3/STAT3, which were obviously lowered by TPL treatment (P < 0.01). TPL-treated RA-FLS overexpressing circRNA 0003353 showed significantly increased cell viability and migration ability with decreased IL-4 expression and increased IL-6 and IL-17 expressions and ratios of p-JAK2/ JAK2 and p-STAT3/STAT3 (P < 0.01). CONCLUSION The expression of circRNA 0003353 is increased in PBMCs in RA patients and in RA-FLS. TPL treatment can regulate JAK2/STAT3 signal pathway and inhibit the inflammatory response and migration of RA-FLS through circRNA 0003353.
Arthritis, Rheumatoid/pathology* ; Cells, Cultured ; Diterpenes/pharmacology* ; Epoxy Compounds/pharmacology* ; Fibroblasts/pathology* ; Humans ; Interleukin-17/metabolism* ; Interleukin-4/metabolism* ; Interleukin-6/metabolism* ; Janus Kinase 2/metabolism* ; Leukocytes, Mononuclear/metabolism* ; Phenanthrenes/pharmacology* ; RNA, Circular/metabolism* ; STAT3 Transcription Factor/metabolism* ; Signal Transduction/drug effects* ; Synovial Membrane/pathology*

OBJECTIVETo observe the expression of peripheral blood CD4+ T lymphocyte apoptosis gene in rheumatoid arthritis (RA) patients with cold dampness type (CDT), and to explore its correlation with clinical indicators of RA.

METHODSSixteen RA patients with CDT (as the RA group) and 16 healthy subjects (as the normal control group) were recruited. CD4 T cell apoptosis rate was detected in the RA group and the normal control group using FCM. mRNA expressions of fas, fasL, caspase-3, caspase-8, bcl-2, and bax were detected using RT-PCR. Correlations between the expression of apoptosis gene and clinical activity indicators of RA (ESR, CRP, RF, CCP, integrals for Chinese medial symptoms, morning stiffness time, joint tenderness number, joint swelling number, DAS28-3) were analyzed.

RESULTSThe apoptosis rate of CD4+ T was significantly lower in the RA group than in the control group [(2. 6 +/- 0.9) % vs. (7.7 +/- 1.3) %, P < 0.01]. mRNA expression levels of fas, fasL, caspase-8, caspase-3, and bax mRNA of CD4+ T significantly decreased, but bcl-2 mRNA expression increased in the RA group (P < 0.01). The apoptosis rate of CD4+ T was negatively correlated with ESR (P < 0.05). The mRNA expression of caspase-8 was negatively correlated with joint swelling number (P < 0.05). The mRNA expression of bcl-2 was negatively correlated with integrals for Chinese medial-symptoms and joint function classification (P < 0.01, P < 0.05).

CONCLUSIONApoptosis obstacle exists in peripheral blood CD4 +T lymphocyte of RA patients, and is closely related to disease activity.

Apoptosis ; Arthritis, Rheumatoid ; diagnosis ; metabolism ; pathology ; CD4-Positive T-Lymphocytes ; Caspase 3 ; metabolism ; Caspase 8 ; metabolism ; Fas Ligand Protein ; Humans ; RNA, Messenger

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 the most common inflammatory arthritis and a major cause of disability. Presently, the clinical therapeutic medicines for inflammatory and arthritic diseases are unsatisfactory due to severe adverse effects or ineffectiveness. The Guge Fengtong formula (GGFT), containing the standardized extracts of Dioscoreae Nipponicae Rhizoma, Spatholobi Caulis, and Zingiberis Rhizoma, has long been used for RA treatment by Chinese doctorsin China. However, the detailed anti-inflammatory and anti-arthritic activity of GGFT has not been reported so far. In the present work, we aimed to evaluate the anti-inflammatory and anti-arthritic effects of GGFT using three in vivo animal models, and tried to uncover its preliminarythe underlying mechanism of action mechanism in RAW 264.7 macrophages. The obtained results indicated that GGFT significantly attenuated ear edema, decreased carrageenan-induced paw edema, reduced the arthritis score, and reversed the weight loss of the complete Freund's adjuvant (CFA)CFA-injected rats. Additionally, marked decrease of in synovial inflammatory infiltration and synovial lining hyperplasia in the joints and decline of inflammatory factors (TNF-α and IL-1β) in the serum were observed in the GGFT-treated rats. In lipopolysaccharide-activated RAW264.7 macrophages, GGFT reduced the production of NO, PGE2, and IL-6, and inhibited the expression of iNOS, COX-2, and NF-κB expression. Our results demonstrated that GGFT possessed considerable anti-inflammatory activity and have had potential therapeutic effects on adjuvant induced arthritis in rats, which provided providing experimental evidences for its traditional application in the treatment of RA and other inflammatory diseases.
Animals ; Anti-Inflammatory Agents ; pharmacology ; therapeutic use ; Antirheumatic Agents ; pharmacology ; therapeutic use ; Arthritis ; Arthritis, Rheumatoid ; drug therapy ; metabolism ; pathology ; Carrageenan ; Cytokines ; blood ; Dioscorea ; Disease Models, Animal ; Drugs, Chinese Herbal ; pharmacology ; therapeutic use ; Fabaceae ; Freund's Adjuvant ; Inflammation ; chemically induced ; drug therapy ; metabolism ; Inflammation Mediators ; metabolism ; Macrophages ; drug effects ; Male ; Mice ; Mice, Inbred ICR ; Phytotherapy ; RAW 264.7 Cells ; Rats, Sprague-Dawley ; Zingiberaceae

S100A8 and S100A9 are major leukocyte proteins, known as damage-associated molecular patterns, found at high concentrations in the synovial fluid of patients with rheumatoid arthritis (RA). A heterodimeric complex of S100A8/A9 is secreted by activated leukocytes and binds to Toll-like receptor 4, which mediates downstream signaling and promotes inflammation and autoimmunity. Serum and synovial fluid levels of S100A8/A9 are markedly higher in patients with RA than in patients with osteoarthritis or miscellaneous inflammatory arthritis. Serum levels of S100A8/A9 are significantly correlated with clinical and laboratory markers of inflammation, such as C-reactive protein, erythrocyte sedimentation rate, rheumatoid factor, and the Disease Activity Score for 28 joints. Significant correlations have also been found between S100A8/A9 and radiographic and clinical assessments of joint damage, such as hand radiographs and the Rheumatoid Arthritis Articular Damage score. In addition, among known inflammatory markers, S100A8/A9 has the strongest correlation with total sum scores of ultrasonography assessment. Furthermore, baseline levels of S100A8/A9 are independently associated with progression of joint destruction in longitudinal studies and are responsive to change during conventional and biologic treatments. These findings suggest S100A8/A9 to be a valuable diagnostic and prognostic biomarker for RA.
Arthritis, Rheumatoid/*blood/pathology/radiography ; Arthrography ; Biological Markers/blood ; Calgranulin A/*blood ; Calgranulin B/*blood ; Humans ; Joints/pathology ; Synovial Fluid/metabolism