A RIPK2 inhibitor delays NOD signalling events yet prevents inflammatory cytokine production

Intracellular nucleotide binding and oligomerization domain (NOD) receptors recognize antigens including bacterial peptidoglycans and initiate immune responses by triggering the production of pro-inflammatory cytokines through activating NF-κB and MAP kinases. Receptor interacting protein kinase 2 (RIPK2) is critical for NOD-mediated NF-κB activation and cytokine production. Here we develop and characterize a selective RIPK2 kinase inhibitor, WEHI-345, which delays RIPK2 ubiquitylation and NF-κB activation downstream of NOD engagement. Despite only delaying NF-κB activation on NOD stimulation, WEHI-345 prevents cytokine production in vitro and in vivo and ameliorates experimental autoimmune encephalomyelitis in mice. Our study highlights the importance of the kinase activity of RIPK2 for proper immune responses and demonstrates the therapeutic potential of inhibiting RIPK2 in NOD-driven inflammatory diseases. Receptor Interacting Protein Kinase 2 (RIPK2) mediates innate immune signalling in response to intracellular pathogens, but its aberrant activation contributes to autoimmune pathologies. Here Nachbur et al.describe a RIPK2 inhibitor that is effective in a mouse model of multiple sclerosis.