FIGURE 1.

Activation of inflammasome requires two signals: signal I is PAMPs or DAMPs close to the cell, sensed by TLRs or NLRs, and activate MAPK or NF-kB signaling pathway, which in turns produces pro-IL-1β and pro-IL-18. Signal II is K⁺, H⁺ or Ca⁺ efflux, or oxidative stress activation by ROS, or lysosomal rupture, leading to the activation of NLRP3 inflammasome. ASC recruits pro caspase-1, which is then is cleaved into active p20 and p10 fragments, followed by the maturation of IL-1β and IL-18, as well as the cleavage of GSDMD, leading to cell pyroptosis. Both of these signals are called the canonical pathway of inflammation activation. When signal II is mediated by caspase-11/caspase-4, it is called the non-canonical activation pathway of inflammasome.