METTL14 and rheumatoid arthritis: Next, we verified the mRNA levels of four essential components of the m6A methylase complex: alkB homolog 5 (ALKBH5), methyltransferase-like 14 (METTL14), fat mass and obesity associated protein (FTO), and methyltransferase-like 3 (METTL3), in RA-FLSs and OA-FLSs using qRT-PCR.