interleukin-1

The inflammasome is a multi protein complex that is an important component of the innate immune response. The inflammasome is able to sense and respond to pathogen infections by recognizing pathogen-associated molecular patterns and mediating the secretion of inflammatory cytokines. Of the various types of inflammasomes, NLRP3/NALP3 is unique because of the diverse range of microbes it is able to detect (1).

While known for their role in programmed cell death, caspases are also essential for mediating inflammatory responses and innate immunity. Binding of microbial molecules by pattern recognition receptors triggers the formation of the multiprotein inflammasome complex and the activation of caspase-1 (1). Caspase-1 is then able to mediate the activation and secretion of proinflammatory cytokines including interleukin-1. In addition to caspase-1, caspase-11 also plays an important role during the inflammatory response.

Caspase-1 is an enzyme involved in the conversion of interleukin-1 into its active secreted form. Interleukin-1 mediates inflammatory responses during infection and disease. Caspase-1 is recruited to and activated by the inflammasome complex (1). Under normal cellular conditions caspase-1 exists in an inactive pro form. Following stimulation with LPS or various microbial signals procaspase-1 is proteolytically cleaved into 10- and 20-kDa subunits that are enzymatically active (2).