Inflammasomes are large intracellular multiprotein complexes that play a central role in innate immunity. They detect and respond to a large range of pathogen-associated molecular patterns (PAMPs), including bacterial flagellin, and damage-associated molecular patterns (DAMPs), such as uric acid crystals.
Inflammasomes comprise a member of the NOD-like receptor (NLR) family, such as NLRP3 and IPAF, and are defined by the NLR protein that they contain. The NLR protein recruits the inflammasome-adaptor protein ASC, which in turn interacts with caspase-1 leading to its activation. Once activated, caspase-1 promotes the maturation of the proinflammatory cytokines interleukin (IL)-1β and IL-18.
Inflammasome activation is crucial for host defense to pathogens but recent studies have also found a role for the inflammasomes in the pathogenesis of several inflammatory diseases such as inflammatory bowel disease, rheumatoid arthritis and atherosclerosis.