Tumor necrosis factor receptor-associated factor (TRAF) 6 inhibition mitigates the pro-inflammatory roles and proliferation of rheumatoid arthritis fibroblast-like synoviocytes.

Rheumatoid arthritis (RA) fibroblast-like synoviocytes (FLSs) play a crucial role in RA through producing inflammatory cytokines and proteases which could cause cartilage destruction. We showed previously that elevated expression of tumor necrosis factor receptor-associated factor 6 (TRAF6) in RA synovium correlated significantly with the severity of synovitis and the number of infiltrated inflammatory cells. The aims of this study are to detect the roles of TRAF6 in RA-FLSs. Synovium were collected by closed needle biopsy from inflamed knees of active RA patients, and FLSs were isolated by modified tissue culture method. Expression of TRAF6 and CD55 in RA synivium was tested by double immunofluorescence (IF) staining. TRAF6 in RA-FLSs was inhibited using Lentiviral-TRAF6-shRNA transfection. Real-time PCR and ELISA were used to detect the mRNA expression and secretion of matrix metalloproteinase (MMP) and pro-inflammatory cytokines. Cell Counting Kit-8 was used to detect cell proliferation, flow cytometry was used to detect cell cycle, and Annexin V assay was used to detect cell apoptosis. We showed that in the intimal and subintimal area of RA synovium, TRAF6 was expressed obviously not only in CD55+ cells, but also in some other CD55- cells. TRAF6 expression in RA-FLSs was suppressed effectively by Lentiviral-TRAF6-shRNA transfection. Inhibition of TRAF6 in RA-FLSs mitigated the mRNA levels and secretion of pro-inflammatory cytokines and MMPs, such as IL-1β, IL-8, IL-6, TNF-α, MMP-13, and MMP-3. In addition, it decreased the proliferation of RA-FLSs, blocked RA-FLSs in G0/G1-phase, and inhibited the cells to go into S-phase and G2/M-phase, but not facilitated apoptosis of RA-FLSs. TRAF6 plays direct roles in the pro-inflammatory effects and proliferation of RA-FLSs. TRAF6 may serve as a potential treatment target in RA.

Zhu LJ ，Yang TC ，Wu Q ，Yuan LP ，Chen ZW ，Luo MH ，Zeng HO ，He DL ，Mo CJ ... -  《-》

CYLD suppression enhances the pro-inflammatory effects and hyperproliferation of rheumatoid arthritis fibroblast-like synoviocytes by enhancing NF-κB activation.

Zhang LM ，Zhou JJ ，Luo CL 《-》

Antagonism of NK-1R using aprepitant suppresses inflammatory response in rheumatoid arthritis fibroblast-like synoviocytes.

Liu X ，Zhu Y ，Zheng W ，Qian T ，Wang H ，Hou X ... -  《-》

Tumor necrosis factor receptor-associated factor 6 promotes migration of rheumatoid arthritis fibroblast-like synoviocytes.

Wang H ，Chen W ，Wang L ，Li F ，Zhang C ，Xu L ... -  《-》

Circ_0004712 Silencing Suppresses the Aggressive Changes of Rheumatoid Arthritis Fibroblast-Like Synoviocytes by Targeting miR-633/TRAF6 Axis.

Circular RNA_0004712 (circ_0004712) is reported to be up-regulated in rheumatoid arthritis (RA) patients. Nevertheless, its role and mechanism in RA pathology remain to be clarified. RNA and protein expression was determined by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blot assay. Cell viability, proliferation, apoptosis, migration, and inflammation were assessed by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, 5-ethynyl-20-deoxyuridine assay, flow cytometry, scratch test, and enzyme-linked immunosorbent assay. The target correlation between microRNA-633 (miR-633) and circ_0004712 or TNF receptor associated factor 6 (TRAF6) was verified by dual-luciferase reporter assay and RNA immunoprecipitation assay. Circ_0004712 was up-regulated in RA synovial tissues and RA fibroblast-like synoviocytes (RA-FLSs). Circ_0004712 silencing suppressed the viability, proliferation, migration and inflammatory response and facilitated the apoptosis of RA-FLSs. miR-633 was confirmed to be a direct target of circ_0004712, and miR-633 knockdown reversed circ_0004712 silencing-mediated protective effects on the dysfunction and inflammation of RA-FLSs. TRAF6 was a direct target of miR-633, and miR-633 overexpression suppressed the aggressive changes of RA-FLSs by down-regulating TRAF6. Circ_0004712 could up-regulate TRAF6 expression by sponging miR-633 in RA-FLSs. Circ_0004712 interference inactivated nuclear factor (NF)-κB signaling by targeting miR-633/TRAF6 axis. Circ_0004712 silencing inhibited the aggressive changes of RA-FLSs by targeting miR-633/TRAF6 axis and NF-κB signaling, which provided new targets for RA therapy.

Zhang S ，Shen Z ，Chao G ，Du X ，Zhang W ，Jin D ，Liu Y ... -  《-》