Activation of canonical and non-canonical inflammasomes. A: Canonical inflammasomes are activated in two steps. First, TLR or NOD1/2 sense PAMPs and DAMPS, which activate NF-κB and induce the expression of pro-IL1β and pro-IL18. Second step involves sensing of PAMPs and DAMPs by NLRs or AIM2 through mechanisms that are not fully understood. NLRP3 and NLRC4 interact with pro-caspase-1 through ASC, whereas NLRP1 interacts with caspase-1 directly. Activated NLRs promote conversion of pro-caspase-1 into caspase-1, which further catalyzes the proteolytic cleavage of pro-IL1β and pro-IL18 resulting in active IL-1β and IL-18. Caspase-1 also induces pyroptotic cell death. B: Non-canonical inflammasomes Malt1 activate caspase-8 and caspase-11, which induce pyroptosis, apoptosis and activation of IL-1β.