Effect of MiR-21 on Regulating the Proliferation of Synovial Fibroblasts in Rheumatoid Arthritis

Abstract

Background: This study investigated whether miR-21 regulates the expression of STAT3 and affects FLS cells. Methods: MiR-21 and STAT3 mRNA level was assessed by qRT-PCR and STAT3 and p-STAT3 level was evaluated by Western blot. Spearman correlation was used to analyze the relationship between miR-21 and STAT3 mRNA expression in synovial tissue of RA patients. FLS cells were treated with IL-17A, and the cells without treatment was included as the control group. Under IL-17A treatment, FLS cells were divided into 2 groups: miR-NC group and miR-21 mimic group. MiR-21, STAT3, p-STAT3 expression were detected and compared. EdU staining was used to detect cell proliferation and flow cytometry was used to measure cell apoptosis. Results: There was a target relationship of miR-21 with STAT3 mRNA. IL-17A treatment significantly downregulated miR-21 in FLS cells, upregulated STAT3 and p-STAT3 and enhanced cell proliferation. Transfection of miR21 mimic significantly downregulated STAT3 and p-STAT3 in FLS cells, reduced cell proliferation and increased cell apoptosis. Conclusion: MiR-21 overexpression down-regulates STAT3, inhibits FLS cell proliferation and promotes apoptosis, indicating that it might be a therapeutic target for treating RA.