A selective jumonji H3K27 demethylase inhibitor modulates the proinflammatory macrophage response

A structure-guided small-molecule and chemoproteomics approach uncovers a catalytic site inhibitor selective for the jumonji subfamily of H3K27me3 demethylases; the inhibitor decreases lipopolysaccharide-induced proinflammatory cytokine production by human primary macrophages. Jumonji (JMJ) family histone demethylases have become recognized as key regulators of transcription, although the importance of their enzymatic activity - as opposed to their structural role - has been unclear. JMJD3 demethylases are specific for histone H3 trimethylated at Lys27 (H3K27me3) and are involved in the inflammatory response, as well as other physiological functions. Here, a structure-guided small-molecule and chemoproteomics approach is used to discover a catalytic-site inhibitor selective for the H3K27me3-specific JMJ subfamily. The inhibitor reduces lipopolysaccharide-induced pro-inflammatory cytokine production in human primary macrophages. This study demonstrates the importance of JMJ demethylase activity and suggests that small-molecule inhibitors of JMJ enzymes could have therapeutic applications. The jumonji (JMJ) family of histone demethylases are Fe2+- and α-ketoglutarate-dependent oxygenases that are essential components of regulatory transcriptional chromatin complexes1,2,3,4. These enzymes demethylate lysine residues in histones in a methylation-state and sequence-specific context5. Considerable effort has been devoted to gaining a mechanistic understanding of the roles of histone lysine demethylases in eukaryotic transcription, genome integrity and epigenetic inheritance2,4,6, as well as in development, physiology and disease3,7. However, because of the absence of any selective inhibitors, the relevance of the demethylase activity of JMJ enzymes in regulating cellular responses remains poorly understood. Here we present a structure-guided small-molecule and chemoproteomics approach to elucidating the functional role of the H3K27me3-specific demethylase subfamily (KDM6 subfamily members JMJD3 and UTX)8. The liganded structures of human and mouse JMJD3 provide novel insight into the specificity determinants for cofactor, substrate and inhibitor recognition by the KDM6 subfamily of demethylases. We exploited these structural features to generate the first small-molecule catalytic site inhibitor that is selective for the H3K27me3-specific JMJ subfamily. We demonstrate that this inhibitor binds in a novel manner and reduces lipopolysaccharide-induced proinflammatory cytokine production by human primary macrophages, a process that depends on both JMJD3 and UTX. Our results resolve the ambiguity associated with the catalytic function of H3K27-specific JMJs in regulating disease-relevant inflammatory responses and provide encouragement for designing small-molecule inhibitors to allow selective pharmacological intervention across the JMJ family.