NLR family pyrin domain containing 3 (NLRP3) (NLRP3)

The NLR family pyrin domain containing 3 (NLRP3) is a cytosolic protein that serves as a critical pattern recognition receptor (PRR) within the innate immune system. It is the primary sensor component of the NLRP3 inflammasome, a multi-protein complex that includes the adapter protein ASC and the effector protease caspase-1. Aluminum phosphate, a common vaccine adjuvant, activates this pathway by inducing lysosomal rupture and cellular stress signals in innate immune cells like macrophages and dendritic cells (Kool et al., 2008; Hornung et al., 2008). This activation leads to the maturation and secretion of the pro-inflammatory cytokines interleukin-1β (IL-1β) and interleukin-18 (IL-18), which are vital for enhancing the adaptive immune response to vaccine antigens. While essential for host defense, dysregulated NLRP3 activity is a key driver of various chronic inflammatory and autoinflammatory diseases, such as gout and Cryopyrin-associated periodic syndromes (CAPS) (Mangan et al., 2018). Consequently, NLRP3 is a major target for drug development, with several small-molecule inhibitors currently being evaluated for their ability to treat systemic and organ-specific inflammatory conditions.

Other names

CryopyrinCIAS1NALP3PYPAF1Caspase recruitment domain-containing protein 7NACHT, LRR and PYD domains-containing protein 3

Aluminum phosphate acts as an adjuvant by triggering the assembly of the NLRP3 inflammasome through lysosomal destabilization and the release of reactive oxygen species (ROS) or cathepsins (Kool et al., 2008; Eisenbarth et al., 2008). Therapeutic inhibitors of NLRP3, such as MCC950 and Dapansutrile, bind to the NACHT domain and inhibit its ATPase activity, thereby preventing the conformational change necessary for inflammasome assembly and the subsequent activation of caspase-1 (Mangan et al., 2018; Coll et al., 2015).