Role of NLRP3 inflammasome in inflammatory bowel diseases

Figure 1 NLRP3 inflammasome structure. NLRP3 inflammasome consists of three major components-the sensor NLRP3 protein, the adaptor-apoptosis-associated speck-like protein (ASC) which contains a N-terminal PYRIN-PAAD-DAPIN domain (PYD) and a C-terminal caspase recruitment domain (CARD) and the effector protein-caspase-1. Activation of NLRP3 occurs when the cell is subjected to pathogen-associated molecular patterns and damage-associated molecular patterns. The stimulated NLRP3 interacts through PYD domain with ASC and pro-caspase-1 binds to ASC via CARD to assemble into a large cytosolic complex, which triggers activation of caspase-1. Active caspase-1 cleaves the pro-inflammatory cytokines interleukin 1β (IL-1β) and IL-18 from their precursors to their biologically active forms inducing inflammation. ASC: Adaptor-apoptosis-associated speck-like protein; CARD: C-terminal caspase recruitment domain; PYD: PYRIN-PAAD-DAPIN domain; IL: Interleukin; PAMPs: Pathogen-associated molecular patterns; DAMPs: Damage-associated molecular patterns.