Abstract:【Objective】 To observe the effects and mechanism of urokinase-type plasminogen activator receptor (uPAR) expression in rheumatoid arthritis fibroblast-like synoviocytes (RA-FLS). 【Methods】 Tissues were collected from RA patients with joint replacement surgery or arthroscopy and RA-FLS were obtained by tissue culture. Chemically synthesized small interference RNA(siRNA) specifically targeting uPAR gene was transfected into RA-FLS by cationic liposome. The interference efficiency of uPAR-siRNA on the production of uPAR mRNA and protein was determined by RT-qPCR and Western blotting respectly. The proliferative inhibition rate was examined by CCK8 assay. Flow cytometry was adopted to determine the change of cell cycle distribution. The migration of RA-FLS was examined by Transwell assay. Western blotting was performed to detect the influence of uPAR on PI3K/AKT signal pathway. 【Results】 Transfection of uPAR-siRNA significantly decreased the mRNA and protein expression of uPAR gene. The proliferative inhibition rate was obviously higher in the uPAR-siRNA group than the control groups (P < 0.05) after transfection for 48 h (17.51 ± 2.27)%

72 h (28.62 ± 4.82)%

96 h (22.91 ± 5.78)%. Flow cytometry assay showed accumulation of cells in the G0/G1 phase and the number of RA-FLS in the S and G2/M decreased; Transwell migration assay demonstrated the RA-FLS through the transwell membrane in uPAR-siRNA group (35 ± 11) were lesser than the NC-siRNA group (136 ± 19) (P < 0.05) and the blank control group (138 ± 21)(P < 0.05). After transfected with uPAR-siRNA

the phosphorylation of PI3K/AKT/GSK3β decreased significantly. 【Conclusion】 uPAR may play a role in the regulation of proliferation

cell cycle and migration of RA-FLS through activation of PI3K/AKT/ GSK3β signal pathway.