Cryo-sensitive aggregation triggers NLRP3 inflammasome assembly in cryopyrin-associated periodic syndrome

Cryopyrin-associated periodic syndrome (CAPS) is an autoinflammatory syndrome caused by mutations of NLRP3 gene encoding cryopyrin. Familial cold autoinflammatory syndrome, the mildest form of CAPS, is characterized by cold-induced inflammation induced by the overproduction of IL-1β. However, the molecular mechanism of how mutated NLRP3 causes inflammasome activation in CAPS remains unclear. Here, we found that CAPS-associated NLRP3 mutants form cryo-sensitive aggregates that function as a scaffold for inflammasome activation. Cold exposure promoted inflammasome assembly and subsequent IL-1β release triggered by mutated NLRP3. While Kefflux was dispensable, Cawas necessary for mutated NLRP3-mediated inflammasome assembly. Notably, Cainflux was induced during mutated NLRP3-mediated inflammasome assembly. Furthermore, caspase-1 inhibition prevented Cainflux and inflammasome assembly induced by the mutated NLRP3, suggesting a feed-forward Cainflux loop triggered by mutated NLRP3. Thus, the mutated NLRP3 forms cryo-sensitive aggregates to promote inflammasome assembly distinct from canonical NLRP3 inflammasome activation.