Periodontal ligament fibroblasts migration injury via ROS/TXNIP/Nlrp3 inflammasome pathway with Porphyromonas gingivalis lipopolysaccharide

Inflammasomes serve as an intracellular machinery to initiate inflammatory response to various danger signals. However, the chronic periodontitis pathological relevance of this inflammasome activation, particularly in periodontal ligament fibroblasts, remains largely unknown. The present study demonstrated that Nlrp3 inflammasome components abundantly expressed in cultured mouse periodontal ligament fibroblasts (mPDLFs). In addition, our data demonstrated that P.g-LPS (Porphyromonas gingivalis Lipopolysaccharide), a major injurious factor during chronic periodontitis, could induce the mPDLFs migration dysfunction and the inhibition of Nlrp3 inflammasome by Isoliquiritigenin (ISO) markedly recovered the migration dysfunction in mPDLFs. And Nlrp3 inflammasome components could be aggregated to form an inflammasome complex on stimulation of P.g-LPS, as shown by fluorescence confocal microscopy. Correspondingly, P.g-LPS induced Nlrp3 inflammasome activation, caspase-1 activation, IL-1 beta and HMGB1 release, which were blocked by Nlrp3 inflammasome inhibitor (ISO). Interestingly, reactive oxygen species, TXNIP protein and TXNIP binding to Nlrp3 were markedly increased in mPDLFs with P.g-LPS. Furthermore, ROS generation inhibitor (Apocynin; APO) significantly reduced Nlrp3 inflammasome formation and IL-1 beta production in mPDLFs with P.g-LPS. And APO attenuated P.g-LPS-induced TXNIP protein expression and mPDLFs injury. In conclusion, our results demonstrate that ROS/TXNIP/Nlrp3 Inflammasome pathway is a key initiating mechanism necessary for P.g-LPS-induced subsequent mPDLFs inflammatory response leading to chronic periodontitis.