METTL14 and rheumatoid arthritis: Further Western blot and protein concentration assay confirmed that compared with those in the RA-FLS + M0 group, RA-FLSs in the RA-FLS + M0 + TNF-α group had increased levels of METTL14, WTAP, and FTO (Figures 4B, C), consistent with the results of immunofluorescence (Figures 4D-I).