GSK484 is a PAD4 inhibitor that effectively inhibits protein citrullination and the formation of neutrophil extracellular traps (NETs) by blocking the catalytic activity of PAD4. GSK484 suppresses the production of histone H3, MHC-I expression, CD8 + T cell activation, proliferation and inflammatory cytokine release. GSK484 reduces inflammation and bone destruction in collagen-induced rheumatoid arthritis, alleviates pain and mast cell activation in sickle cell disease, and improves myocardial ischemia-reperfusion injury and experimental colitis. In addition, GSK484 restores intestinal microbial homeostasis by reversing ferroptosis-induced dysbiosis. GSK484 can be used to study the disease mechanisms of rheumatoid arthritis, sickle cell disease, thrombosis, myocardial injury, colitis and other conditions .