The effect of NLRP inflammasome on the regulation of AGEs‐induced inflammatory response in human periodontal ligament cells

Abstract Background and Objective Diabetes influences the frequency and development of periodontitis. Inflammation of human periodontal ligament cells ( HPDLC s) participates in this pathologic process. Hence, this study aims to explore whether advanced glycation end products ( AGE s), by‐products of diabetes, could exaggerate inflammation induced by muramyl dipeptide ( MDP ) in HPDLC s, and whether nucleotide‐binding oligomerization domain‐like receptors ( NLR s) signaling pathway was involved. Material and Methods Human periodontal ligament cells were pre‐treated with 100 μg/mL AGE s for 24 hours and stimulated with 10 μg/mL MDP for 24 hours. IL ‐6, IL ‐1β, and RAGE were detected, and the activation of NF ‐κB signaling pathway was observed. The expression of NLR s was evaluated with or without silencing RAGE or blocking NF ‐κB pathway under AGE s stimulation. Statistical analyses were performed by using independent sample t test. Results Advanced glycation end products induced significant increase of inflammatory cytokines in HPDLC s ( P < 0.05). Results of western blot ( WB ) showed that after 45 minutes stimulation of AGE s, p‐p65/p65 ratio peaked; AGE s promoted the expression of NLRP 1, NLRP 3, and apoptosis‐associated speck‐like protein containing a CARD ( ASC ). After silencing RAGE or blocking NF ‐κB pathway, the up‐regulation of NLR s protein caused by AGE s was attenuated. Additionally, AGE s pre‐treatment could enhance the inflammatory response of MDP and the expression of NLR s, which were demonstrated by more expression of IL ‐6, IL ‐1β, NOD 2, NLRP 1, NLRP 3, and ASC . Conclusion Advanced glycation end products induced inflammatory response in HPDLC s via NLRP 1‐inflammasome and NLRP 3‐inflammasome activation in which NF ‐κ B signal pathway was involved. Besides, AGE s promoted the inflammatory response of MDP via NOD 2, NLRP 1‐inflammasome, and NLRP 3‐inflammasome.