CASP1 and periodontal disorder: In the present study, LPS elicits a striking immune response through up-regulation of the gene expression of NLRP3 and ASC, but not caspase-1, which indicates that P. gingivalis LPS would be a key factor in eliciting the inflammatory response that leads to the diseased state [16] and is considered an important virulence factor in the pathogenesis of periodontal disease.