CASP1 and colitis: Animal studies using dextran sulfate sodium (DSS)-induced colitis and 2,4,6- trinitrobenzene sulfonic acid solution (TNBS)-induced colitis demonstrated that NLRP3−/− and caspase-1−/− mice exhibited severe colitis compared to wild-type (WT) mice; this aggravation of colitis was due to a lack of IL-18, although the opposite effect of NLRP3 and caspase-1 against DSS-induced colitis was reported by another group9, 10, 11.