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

White fat cells secrete adipokines that induce inflammation and obesity has been reported to be characterized by high serum levels of inflammatory cytokines such as IL-6 and TNF-alpha. Rheumatoid arthritis (RA) is a prototype of inflammatory arthritis, but the relationship between RA and obesity is controversial. We made an obese inflammatory arthritis model: obese collagen-induced arthritis (CIA). C57BL/6 mice were fed a 60-kcal high fat diet (HFD) from the age of 4 weeks and they were immunized twice with type II collagen (CII). After immunization, the obese CIA mice showed higher arthritis index scores and histology scores and a more increased incidence of developing arthritis than did the lean CIA mice. After treatment with CII, mixed lymphocyte reaction also showed CII-specific response more intensely in the obese CIA mice than lean CIA. The anti-CII IgG and anti-CII IgG2a levels in the sera of the obese CIA mice were higher than those of the lean CIA mice. The number of Th17 cells was higher and the IL-17 mRNA expression of the splenocytes in the obese CIA mice was higher than that of the lean CIA mice. Obese CIA mice also showed high IL-17 expression on synovium in immunohistochemistry. Although obesity may not play a pathogenic role in initiating arthritis, it could play an important role in amplifying the inflammation of arthritis through the Th1/Th17 response. The obese CIA murine model will be an important tool when we investigate the effect of several therapeutic target molecules to treat RA.
Adipokines/immunology/metabolism ; Animals ; *Arthritis, Experimental/genetics/immunology/pathology ; Cell Differentiation/genetics/immunology ; *Collagen Type II/administration & dosage/immunology ; Disease Models, Animal ; Gene Expression ; Humans ; Inflammation/chemically induced/*immunology ; Interleukin-17/metabolism ; Interleukin-6/blood ; Joints/immunology/pathology ; Mice ; Mice, Inbred C57BL ; *Obesity/genetics/immunology/pathology ; *Th17 Cells/immunology/metabolism ; Tumor Necrosis Factor-alpha/blood

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

OBJECTIVETo study the effect of Yangqixue Qufengshi Recipe (YQXQFS) on rheumatoid arthritis (RA) model mice under different genetic backgrounds.

METHODSCollagen Induced Arthritis (CIA) were established on HLA-DR4 transgenic (TG) mice and non-transgenic (NTG) mice, which partly were raised with YQXQFS, and the onset day of CIA, the level of type II collagen (CII)-reactive antibodies and the pathological scores of CIA were assessed.

RESULTSUnder HLA-DR4 TG background (compared with NTG mice), the earlier onset day of CIA (11.22 +/- 3.35 days vs 16.56 +/- 4.75 days, P < 0.05) and higher level of CII-reactive antibodies (0.2274 +/- 0.1390 microg/ml vs 0.1101 +/- 0.0560 microg/ml, P < 0.05) were observed, but the pathological scores of CIA remained unchanged. YQXQFS could not influence the onset day of CIA and the level of CII-reactive antibodies, but had a certain effect on the total pathological scores (6.56 +/- 3.43 scores vs 11.11 +/- 5.64 scores) and bone erosion (0.22 +/- 0.44 scores vs 1.67 +/- 1.50 scores) of CIA on NTG mice (P < 0.05), NTG YQXQFS group compared with NTG experimental group.

CONCLUSIONYQXQFS had a certain effect on RA model, but had no significant effect on HLA-DR4 related CIA.

Animals ; Antibodies ; blood ; Antirheumatic Agents ; therapeutic use ; Arthritis, Experimental ; drug therapy ; Arthritis, Rheumatoid ; drug therapy ; immunology ; pathology ; Collagen Type II ; immunology ; Drugs, Chinese Herbal ; therapeutic use ; HLA-DR4 Antigen ; genetics ; Mice ; Mice, Inbred Strains ; Mice, Knockout

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

AIMTo study the effects of TNF receptor blocking peptide on adjuvant arthritis in rats.

METHODSThe model of rat adjuvant arthritis was induced by injection of complete Freund's adjuvant. The TNF receptor blocking peptide was injected locally in the ankle. The ankle swelling, the pathologic changes in the ankle joint and the expression of IL-1 beta mRNA and TNF-alpha mRNA by peritoneal macrophages (RT-PCR) were observed.

RESULTSThe model of rat adjuvant arthritis induced by injection of complete Freund's adjuvant was similar to human rheumatoid arthritis. The treatment with TNF receptor blocking peptide for 10 days resulted in complete inhibition of joint swelling, a decrease in infiltration of inflammatory cell into joint tissue, an obvious alleviation of inflammatory pathological damages and an apparent decline of TNF-alpha mRNA and IL-1 beta mRNA of peritoneal macrophages of rats.

CONCLUSIONThe TNF receptor blocking peptide can protect the joint from inflammatory damage induced by adjuvant arthritis by suppression of TNF-alpha and IL-1 production, thereby alleviating the pathological injury of joint and controlling effectively the clinic course of arthritis.

Animals ; Ankle Joint ; pathology ; Arthritis, Experimental ; immunology ; pathology ; Interleukin-1 ; biosynthesis ; genetics ; Macrophages, Peritoneal ; metabolism ; Male ; Peptides ; pharmacology ; RNA, Messenger ; genetics ; Rats ; Rats, Wistar ; Receptors, Tumor Necrosis Factor ; antagonists & inhibitors ; Tumor Necrosis Factor-alpha ; biosynthesis ; genetics

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

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