KDM4B and rheumatoid arthritis: After RA FLS were, respectively, transfected with shKDM4B-1#, shKDM4B-2#, and shNC, western blot showed that the protein expression of KDM4B between shNC transfection and blank control groups had no significant difference, but shKDM4B-1# and shKDM4B-2# obviously suppressed the expression of KDM4B as compared to shNC group (Fig. 2a).