HDAC9 and rheumatoid arthritis: In addition, HDAC inhibitors (HDACi) and BET protein inhibitors (I-BET) have shown strong efficacy in preclinical models of several inflammatory and autoimmune diseases, such as models of inflammatory bowel disease (IBD) and rheumatoid arthritis (RA) [18,19,20,21,22,23,24,25,26].