MMP2 and rheumatoid arthritis: Circ_0088194 is localized mostly in the cytoplasm of RA-FLSs and bioinformatic analysis using three publicly available databases (TargetScan, miRanda, and circular RNA interactome) indicated that miR-766-3p and miR-635 might bind to Circ_0088194 and the 3′-untranslated region (UTR) of MMP2 mRNA (Figure 4A).