Biphasic JNK signaling reveals distinct MAP3K complexes licensing inflammasome formation and pyroptosis.

Abstract

Kinase signaling in the tiered activation of inflammasomes and associated pyroptosis is a prime therapeutic target for inflammatory diseases. While MAPKs subsume pivotal roles during inflammasome priming, specifically the MAP3K7/JNK1/NLRP3 licensing axis, their involvement in successive steps of inflammasome activation is poorly defined. Using live-cell MAPK biosensors to focus on the inflammasome triggering event allowed us to identify a subsequent process ofbiphasic JNK activation. We find that this biphasicpost-trigger JNK signaling initiallyfacilitates themitochondrial reactive oxygen species generation needed to support core inflammasome formation, then supports thegasdermin-mediated cell permeation required forrelease of active IL-1β from human macrophages. We further identify and characterize a xanthine oxidase-ROS activated MAP3K5/JNK2 substrate licensing complex as a novel regulator of theGSDMD mobilizationwhich precedes pyroptosis. We showthat inhibitors targeting this MAP3K5 cascade alleviate morbidity in mouse models of colitis and dampen both augmented IL-1β release and cell permeation in monocytes derived from patients with gain-of-function inflammasomopathies.