miR-26a-5p Regulates Synovial Fibroblast Invasion in Patients with Rheumatoid Arthritis by Targeting Smad 1

BACKGROUND: We studied the expression and effect of miR-26a-5p in synovial fibroblast in patients with rheumatoid arthritis (RA). MATERIAL/METHODS: The synovial tissues of 55 RA patients with total knee arthroplasty performed from January 2016 to December 2016 were collected as the RA group, and 62 patients without RA history amputation or total knee arthroplasty served as the control group. The expressions of miR-26a-5p and Smad 1 mRNA in synovial fibroblast in patients with RA were detected by qPCR; The expression of Smad 1 and TGF-β1 protein in synovial tissue or synovial fibroblasts was detected by immunoblotting. Transwell assay was used to detect the invasive ability of synovial fibroblasts. RESULTS: The expression of miR-26a-5p and Smad 1 in synovial fibroblast in patients with RA were significantly higher than those in the control group (P<0.05). The expression of miR-26a-5p in synovial tissue of RA patients was positively correlated with the expression of Smad 1 mRNA (r=0.8982, P<0.001). The luciferase system showed that miR-26a-5p targeting synovial membrane FLS cells (P<0.05); the expression of MMP-1, MMP-3, MMP-13, and TGF-β1 protein and mRNA in the synovial FLS cells of RA patients was significantly decreased; and the expression of miR-26a-5p was significantly decreased in FLS cells with invasive ability. CONCLUSIONS: miR-26a-5p is highly expressed in synovial tissue of patients with RA, and its high expression can improve the invasive ability of synovial fibroblasts by targeting Smad 1 gene and accelerating the progression of RA.