PTGS2 and rheumatoid arthritis: We found that miR-199a-3p correlated inversely with PTGS2 expression in RA patients’ MCs (r = − 0.698, P = 0.010; Fig. 5C), suggesting that miR-199a-3p may be a regulator of PTGS2 mRNA expression in RA patients’ synovial MCs.