The ratio of Treg/Th17 has been used to characterize the severity of RA (45, 46), and our results showed that GSK-J4 could downregulate the ratio of Treg/Th17 (Figure S2), further suggesting that inhibition of demethylase activity could be beneficial to CIA, at least in the experimental RA mice model. Here, MBD2 is linked to rheumatoid arthritis.