Inflammasomes and inflammation

Engagement of pattern recognition receptors (PRRs) initiates signal transduction pathways that usually culminate in the elimination of pathogens and/or the initiation of tissue repair processes. A major pro-inflammatory pathway mediating host defense against infection is triggered by inflammasomes, multiprotein complexes that regulate the function of the pro-inflammatory caspase, caspase-1. Caspase-1, in turn, controls the maturation and secretion of pro-inflammatory cytokines such as interleukin (IL)-1β and IL-18 and the induction of inflammatory cell death (pyroptosis). Inflammasome assembly is mediated by members of the NOD-like receptor (NLR) or pyrin and HIN domain-containing (PYHIN) families of "danger" sensor proteins. This chapter focuses on certain types of inflammasomes namely, NLRP3 inflammasome, IPAF inflammasome, NLRP1 inflammasome, NLRP12 inflammasome, NLRP7 inflammasome, NLRP6 inflammasome, and AIM2 inflammasome. Numerous and diverse human disorders of wide-ranging etiology arise from, or are exacerbated by, the dysregulation of inflammasome activity. They include genetic disorders, autoimmune conditions, and metabolic diseases.