E2F2 stimulates CCR4 expression and activates synovial fibroblast-like cells in rheumatoid arthritis

AIM OF THE STUDY: E2F transcription factor 2 (E2F2) has increased expression in synovial tissues of rheumatoid arthritis (RA) and stimulates interleukin (IL)-1 α and IL-β production in cultured RA synovial fibroblast-like cells (RASF), which supports the importance of E2F2 in RA pathogenesis. This study investigated the effect and mechanism of E2F2 in RA. MATERIAL AND METHODS: Cultured RASF were transfected with anti-E2F2 siRNA, and the expression profile was analyzed with an inflammatory response and autoimmunity PCR array loaded with 84-relative genes to explore the pathogenic pathway of E2F2. Apoptosis, migration and tube-like structure formation in the RASF with transfection of anti-E2F2 siRNA or E2F2-expressing plasmids were examined using flow cytometry, transwell assays and Matrigel assays, respectively. RESULTS: Significantly decreased expression of chemokine receptor 4 (CCR4) was detected in RASF with inhibited E2F2 expression, and the CCR4 expression was increased in RASF with transfection of E2F2-expressing plasmids. Silencing E2F2 expression stimulated apoptosis, but retarded migration and tube-like structure formation in RASF. The opposite observation was obtained in RASF with E2F2 overexpression. CONCLUSIONS: High E2F2 expression decreases apoptosis and increases migration and tube-like structure ability in RASF and might perform this role by up-regulating CCR4 expression, which ultimately contributes to the disease progression of RA synovial tissues.