Regulation of caries‐induced pulp inflammation by NLRP3 inflammasome: A laboratory‐based investigation

Aim To evaluate the expression and function of the nod‐like receptor pyrin domain containing 3 (NLRP3) inflammasome in caries induced pulpitis. Methodology NLRP3 expression was determined with immunohistochemistry in the dental pulp and qPCR in dental pulp cells (DPCs). THP‐1 macrophages expressing the apoptosis‐related speck‐like protein (ASC) and green fluorescent protein (GFP) fusion protein were used to assess NLRP3 inflammasome activation by live cell imaging, following treatment with lipopolysaccharide (LPS) and lipoteichoic acid (LTA). Caspase I inhibitor was used to confirm inflammasome activation. An ex‐vivo pulpitis model in which the DPCs were co‐cultured with THP‐1 macrophages was used to study the effect of the NLRP3 inflammasome inhibitor (MCC950), and cytokines were measured using ELISA and multiplex array. Data were analysed using the t‐test or anova followed by a Bonferroni post hoc test with the level of significance set at p ≤ .05. Results NLRP3 inflammasome was differentially expressed in dental pulp of sound and carious teeth. Treatment of DPCs with LTA significantly upregulates NLRP3 and IL‐1 β‐expression (p