OBJECTIVETo investigate the role of natural killer-22 (NK-22) cells in the synovial fluid in the proliferation of fibroblast-like synoviocytes (FLS) in patients with rheumatoid arthritis (RA) and explore the possible signal pathway involved.

METHODSNK-22 cells in the SF of RA patients were sorted by flow cytometry. NK-22 cells were cultured for two weeks and the purity was detected by flow cytometry before stimulation with 20 ng/ml phorbol 12-myristate 13-acetate and 0.5 µmol/L ionomycin for 4 h. The level of interleukin-22 (IL-22) in the culture medium supernatant was then measured with ELISA. The proliferation of FLS in the presence of the culture supernatant of NK-22 cells was assessed with MTT assay at 24, 48 and 72 h, and the effect of IL-22 antibody on FLS proliferation was also observed. Real-time PCR and Western blotting were used to detect Stat3 mRNA and p-Stat3 protein levels, respectively, in the FLS exposed to rhIL-22 and AG490.

RESULTSNK-22 cells were successfully sorted by flow cytometry with a purity exceeding 90%. The levels of IL-22 in the supernatant of NKp44(+)NK cell culture averaged 1273.42∓254.48 pg/ml. The FLS proliferated rapidly 24, 48, and 72 h after the addition of culture supernatant of NK-22 cells (P<0.05). IL-22 antibody obviously inhibited the proliferation of FLS induced by NK-22 cell culture supernatant (P<0.05). Exposure of the FLS to rhIL-22 obviously increased cellular Stat3 expression levels, which were significantly lowered by the addition of AG490 (P<0.05).

CONCLUSIONNK-22 cells in the SF of RA patients can produce high concentrations of IL-22 to promote the proliferation of FLS through the STAT3 signal pathway.

Arthritis, Rheumatoid ; metabolism ; Cell Proliferation ; Cells, Cultured ; Fibroblasts ; cytology ; Humans ; Interleukins ; metabolism ; Killer Cells, Natural ; cytology ; metabolism ; STAT3 Transcription Factor ; metabolism ; Signal Transduction ; Synovial Fluid ; cytology ; Synovial Membrane ; cytology

Animals ; Arthritis, Experimental ; metabolism ; pathology ; Breast Neoplasms ; pathology ; Cadherins ; metabolism ; physiology ; Cell Movement ; Female ; Fibroblasts ; cytology ; pathology ; Humans ; Macrophages ; cytology ; pathology ; Neoplasm Invasiveness ; Synovial Membrane ; cytology ; metabolism ; pathology

The progress of research on the the anterior cruciate ligament (ACL) wound healing demonstrates that the synovial tissue in the knee joint plays a very important role in the healing process of injured ACL. Therefore, the molecular response mechanisms of lysyl oxidase (LOX) and matrix metalloproteina (MMP) in normal/injured ACL fibroblast cells could be considered to perform the major analysis function of injured ACL healing mechanism. The mRNA expressions of LOXs and MMPs and the activity expressions of MMP-2 in ACL fibroblasts co-cultured with synovial cells were analyzed by quantitative real-time PCR and zymography. The results showed that co-culture could regulate the mRNA expressions of LOXs and MMPs in the ACL fibroblasts cells. These results suggest that the differential expressions of LOXs and MMP-1, 2, 3 in co-cultured ACL indicate that interaction crosstalk do exist between ACL cells and synovial cells and provide a theoretical basis for subsequent exploration of the mechanisms and treatment of ACL injury and repair.
Anterior Cruciate Ligament ; cytology ; Anterior Cruciate Ligament Injuries ; Coculture Techniques ; Fibroblasts ; cytology ; metabolism ; Humans ; Knee Injuries ; physiopathology ; Knee Joint ; cytology ; Matrix Metalloproteinases ; genetics ; metabolism ; Protein-Lysine 6-Oxidase ; genetics ; metabolism ; Synovial Membrane ; cytology ; Wound Healing ; physiology

OBJECTIVETo investigate the expression of anaphylatoxin receptor C5aR (CD88) in synoviocytes from patients with rheumatoid arthritis (RA) and osteoarthritis (OA).

METHODSThe expression of C5aR was assessed in synoviocytes isolated from 27 RA and 12 OA patients using reverse transcription-polymerase chain reactions (RT-PCR), flow cytometry, and immunofluorescence analysis. The effects of C5a on the release of tumor necrosis factor alpha (TNF alpha) from synoviocytes were assayed using enzyme-linked immunosorbent assays (ELISA).

RESULTSC5aR mRNA was detected in 24 of 27 samples from RA patients, and 10 of 12 samples from OA patients. Flow cytometric analysis and immunofluorescence study demonstrated the cell surface expression of C5aR in a significant proportion of synoviocytes from both RA and OA patients, and the level of C5aR expression in synoviocytes was significantly correlated with joint swelling, erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) in RA patients. Finally, interaction of C5aR with its ligand C5a was shown to enhance lipopolysaccharide (LPS)-induced TNF alpha release from synoviocytes.

CONCLUSIONSThe expression of C5aR in synoviocytes from inflammatory joint diseases and also the induction of TNF alpha release in activated synoviocytes by the interaction of C5a and C5aR suggest that the C5a/C5aR system may play an important role in joint inflammation process.

Adult ; Aged ; Arthritis, Rheumatoid ; metabolism ; Cells, Cultured ; Female ; Humans ; Male ; Middle Aged ; Osteoarthritis ; metabolism ; Receptor, Anaphylatoxin C5a ; analysis ; Synovial Membrane ; chemistry ; cytology

OBJECTIVETo study the effect and related mechanism of seaweed polysaccharide (SP) on apoptosis of fibroblast-like synoviocytes in patients with rheumatoid arthritis (RA-FLS).

METHODSRA-FLS were in vitro cultured using modified tissue culture method. Effect of SP (0, 15, 20, and 25 mg/mL, respectively) at different time points (0, 3, 4, and 5 days, respectively) on the proliferation and apoptosis of RA-FLS, and protein expressions of Caspase-3, Bax, and Bcl-2 was detected by cell counting kit-8 (CCK-8) assay, Hoechst 33258 staining assay, TUNEL assay, and Western blot, respectively.

RESULTSCompared with 0 mg/mL SP at the same time point, the proliferation of RA-FLS was inhibited, and the apoptosis was promoted 3, 4, and 5 days after intervened by 15, 20, and 25 mg/mL SP, respectively (P<0.01) in time- and dose-dependent manners. RA-FLS Bax protein expression was up-regulated, Bcl-2 protein expression down-regulated, Caspase-3 activated and split by 15, 20, and 25 mg/mL SP, respectively for 4 days (P<0.05, P<0.01). Besides, the changes were in a dose-dependent manner.

CONCLUSIONSSP could inhibit RA-FLS proliferation and induce its apoptosis in dose- and time-dependent manners. Its apoptosis mechanism might be through up-regulating intracellular Bax protein expression and down-regulating Bcl-2 protein expression, thus influencing the mitochondrion signaling pathway, further promoting Caspase-3 activation and split, resulting in the apoptosis of RA-FLS.

Apoptosis ; drug effects ; Arthritis, Rheumatoid ; pathology ; Caspase 3 ; metabolism ; Cells, Cultured ; Fibroblasts ; cytology ; drug effects ; Humans ; Polysaccharides ; pharmacology ; Proto-Oncogene Proteins c-bcl-2 ; metabolism ; Seaweed ; Synovial Membrane ; cytology ; drug effects ; bcl-2-Associated X Protein ; metabolism

OBJECTIVETo examine the expression of FLICE-inhibitory protein (FLIP) in juvenile idiopathic arthritis (JIA) and analyze its correlation with synovial inflammation.

METHODSThe expression of FLIP was assessed in 11 JIA and 3 normal synovial tissue samples by reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry. The cell types expressing FLIP were further characterized, and the correlation of FLIP expression with the degree of synovial inflammation, as well as the activity of caspase 8 was then analyzed.

RESULTSRT-PCR revealed the expression of FLIP mRNA in all 11 JIA samples, but not in 3 normal synovial tissues. In JIA, FLIP expression could be found in both the lining and sublining layers, mainly in the macrophage-like cells. Moreover, the expression of FLIP in JIA synovial tissues was positively correlated with the degree of synovial inflammation (r = 0.563, P < 0.05).

CONCLUSIONThe expression of antiapoptotic FLIP in JIA synovial tissue and its correlation to accumulation of inflammatory cells in synovial tissue suggests that FLIP potentially extends the lifespan of synovial cells and thus contributes to the progression of joint destruction.

Adolescent ; Arthritis, Juvenile ; metabolism ; pathology ; CASP8 and FADD-Like Apoptosis Regulating Protein ; genetics ; metabolism ; Caspase 8 ; metabolism ; Child ; Female ; Humans ; Inflammation ; metabolism ; pathology ; Male ; Protein Isoforms ; genetics ; metabolism ; Synovial Membrane ; cytology ; metabolism ; pathology

Arthritis, Rheumatoid ; metabolism ; Cells, Cultured ; HSP72 Heat-Shock Proteins ; pharmacology ; Humans ; Interleukin-10 ; metabolism ; Synovial Membrane ; cytology ; drug effects ; metabolism ; Toll-Like Receptor 2 ; metabolism ; Toll-Like Receptor 4 ; metabolism

BACKGROUNDThe synovial fluid concentrations of adiponectin are significantly higher in patients with rheumatoid arthritis (RA) than in patients with osteoarthritis (OA). Accumulating evidence suggests that adiponectin may be an inducer of inflammation in arthritis, but the mechanism remains unclear. The objectives of this study were to compare the expression levels of adiponectin receptors in rheumatoid arthritis synovial fibroblasts (RASF) and osteoarthritis synovial fibroblasts (OASF), evaluate the roles of adiponectin receptors in adiponectin-induced prostaglandin E(2) (PGE(2)) production, and then investigate the effects of a nonsteroidal anti-inflammatory drug (NSAID) and a cyclooxygenase (COX)-2-selective inhibitor on adiponectin-induced PGE(2) release.

METHODSThe expressions of adiponectin receptor 1 (AdipoR1) and AdipoR2 mRNA and protein in synovial fibroblasts from seven patients with RA and eight patients with OA undergoing total knee replacement were evaluated by real-time polymerase chain reaction, immunofluorescence microscopy and Western blotting analysis. Adiponectin-induced PGE(2) production was detected by enzyme-linked immunosorbent assay. RNA interference against the AdipoR1 and AdipoR2 genes was performed to investigate the effects of the adiponectin receptors on adiponectin-induced PGE(2) production in both RASF and OASF.

RESULTSAdipoR1 and AdipoR2 mRNA and protein were expressed by both RASF and OASF. Compared with OASF, RASF exhibited higher levels of AdipoR1, but there was no significant difference for AdipoR2. Adiponectin induced the production of PGE(2) by the synovial fibroblasts in a concentration-dependent manner, and this was more obvious in RASF. RNA interference showed that the difference may be mediated by the diverse distribution of AdipoR1. The adiponectin-induced PGE(2) production was efficiently relieved by the NSAID and COX-2-selective inhibitor.

CONCLUSIONThe present findings suggest that AdipoR1 may mediate the difference in adiponectin-induced PGE(2) production in RASF and OASF.

Adiponectin ; pharmacology ; Arthritis, Rheumatoid ; metabolism ; Blotting, Western ; Cells, Cultured ; Dinoprostone ; metabolism ; Female ; Fibroblasts ; drug effects ; metabolism ; Humans ; Immunoassay ; Male ; Microscopy, Fluorescence ; Middle Aged ; Osteoarthritis ; metabolism ; RNA, Small Interfering ; Real-Time Polymerase Chain Reaction ; Receptors, Adiponectin ; genetics ; metabolism ; Synovial Membrane ; cytology

Myeloid-related protein (MRP)8/MRP14 is an endogenous Toll-like receptor 4 (TLR4) ligand and is abundant in synovial fluid (SF) of rheumatoid arthritis (RA) patients. Belonging to damage-associated molecular patterns, it amplifies proinflammatory mediators and facilitates a wide range of inflammatory and autoimmune diseases. Interleukin (IL)-17-producing T-helper (Th)17 cells have a crucial role in RA pathogenesis, and IL-6 is the key factor promoting Th17 differentiation. We investigated whether the level of MRP8/MRP14 is positively associated with IL-6 and IL-17 levels in RA SF and found that MRP8/MRP14 level had a significant correlation with IL-6 and IL-17 levels in RA SF. We also observed that MRP8-induced IL-17 production by peripheral blood mononuclear cells but MRP14 did not. Upon stimulation with MRP8, IL-6 production was enhanced by RA fibroblast-like synoviocytes (FLS) and was further elevated by coculturing RA FLS with activated CD4+ T cells. Moreover, we demonstrated that MRP8-activated IL-6 production by RA FLS promoted differentiation of Th17 cells using the coculture system consisting of CD4+ T cells and RA FLS. In addition, IL-6 blockade attenuated Th17 polarization of CD4+ T cells in the cocultures. Inhibitor studies revealed that MRP8 increased IL-6 production in RA FLS via TLR4/phosphoinositide 3-kinase/nuclear factor-kappaB and mitogen-activated protein kinase signaling pathways. Our results show that MRP8 has a crucial role in stimulating IL-6 expression by RA FLS, and subsequently promotes Th17 differentiation in RA, suggesting that neutralizing MRP8 level in RA synovium may be an effective therapeutic strategy in RA treatment.
ATP-Binding Cassette Transporters/*metabolism ; Adult ; Aged ; Arthritis, Rheumatoid/*pathology ; CD4-Positive T-Lymphocytes/metabolism ; Calgranulin B/metabolism ; Cell Differentiation/*immunology ; Fibroblasts/*metabolism/pathology ; Humans ; Inflammation Mediators/metabolism ; Interleukin-17/metabolism ; Interleukin-6/*biosynthesis ; Middle Aged ; Signal Transduction/immunology ; Synovial Fluid/cytology ; Synovial Membrane/metabolism/pathology ; Th17 Cells/*pathology ; Toll-Like Receptor 4/metabolism ; *Up-Regulation

OBJECTIVETo observe the effect of Sanshui Baihu Decoction (SBD) containing serum on the proliferation of in vitro cultured fibroblast-like synoviocytes (FLS) derived from rheumatoid arthritis (RA) and osteoarthritis (OA) and its secretion of interleukin-6 (IL-6) and IL-17, and to explore the pharmacological mechanism of SBD.

METHODSThe FLS obtained from cultured RA and OA patients' synovial tissue were cultured and passaged in vitro in a routine way. The cultured medium was changed to DMEM with 20% SBD containing serum and cultured for 72 h after cultured for 3 to 6 generations. The proliferation rate of FLS was detected by MTT assay. Levels of IL-6 and IL-17 in the supernatant were detected by ELISA. Leflunomide and saline containing serum were used as positive and negative control respectively.

RESULTSSBD containing serum significantly inhibited the proliferation of RA-FLS and OA-FLS, and decreased the secretion of IL-17 in RA-FLS. Its inhibition efficiency of SBD was equivalent to that of Leflunomide. No obvious inhibition on the secretion of IL-6 in RA-FLS was observed. It had no significant effect on the secretion of IL-17 and IL-6 in OA-FLS.

CONCLUSIONSBD could inhibit the proliferation of FLS and the secretion of IL-17 in RA-FLS, which might be one of its pharmacological mechanisms for treating RA.

Animals ; Arthritis, Rheumatoid ; metabolism ; Cell Proliferation ; drug effects ; Cells, Cultured ; Drugs, Chinese Herbal ; administration & dosage ; pharmacology ; Fibroblasts ; drug effects ; secretion ; Humans ; Interleukin-17 ; metabolism ; Interleukin-6 ; metabolism ; Male ; Rats ; Rats, Sprague-Dawley ; Synovial Membrane ; cytology ; drug effects