MMP9 and rheumatoid arthritis: Both factors act by sponging miRNAs, namely, miR-382-5p, miR-575, and miR-4701-5p (Table S1), and their upregulation promotes cell proliferation, migration, and invasion and induces the production of proinflammatory cytokines and proteinases, including IL-6, IL-8, and MMP-9 (matrix metalloproteinase-9), in RA-FLSs [34, 35].