The histone H3 lysine 27 (H3K27) demethylase JMJD3 plays important roles in the transcriptional regulation of cell differentiation, development, the inflammatory response, and cancer. GSK-J4 (hydrochloride) is an ethyl ester derivative of the JMJD3 selective histone demethylase inhibitor GSK-J1 with an IC50 value greater than 50 μM in vitro. Acting as a prodrug, GSK-J4 is rapidly hydrolyzed in cells to the otherwise cell impermeable GSK-J1, which exhibits an IC50 value of 60 nM for the purified enzyme. When administered to human primary macrophages, GSK-J4 can reduce LPS-induced proinflammatory cytokine production, most notably including that of TNFα (IC50 = 9 μM).
