NLRP3 inflammasome may regulate inflammatory response of human periodontal ligament fibroblasts in an apoptosis-associated speck-like protein containing a CARD (ASC)-dependent manner.
AIM
To explore the role of NLRP3 (NACHT [nucleotide-binding oligomerization], LRR [leucine-rich repeat] and PYD [pyrin domain] domains-containing protein 3) inflammasome in the inflammatory response of human periodontal ligament fibroblasts (HPDLFs).


METHODOLOGY
The expression of NLRP3 and apoptosis-associated speck-like protein containing a CARD (ASC) in inflammatory periapical tissues and HPDLFs was examined by immunohistochemical and immunofluorescent staining. HPDLFs were stimulated with muramyl dipeptide (MDP) and lipopolysaccharide (LPS) from E. coli with or without the silencing of ASC. The expression of NLRP3, ASC and caspase-1 was examined using quantitative real-time polymerase chain reaction. The secretion of proinflammatory cytokines, including interleukin-1β (IL-1β), interleukin-6 (IL-6) and tumour necrosis factor-α (TNF-α) was measured in the cell supernatant with an enzyme-linked immunosorbent assay. Data were statistically analysed using independent sample t-tests.


RESULTS
Immunohistochemistry and immunocytochemistry staining revealed that NLRP3 and ASC were expressed in HPDLFs and inflammatory periapical tissues. MDP and LPS promoted the expression of NLRP3, ASC and caspase-1 in HPDLFs (P < 0.05). The secretion of proinflammatory cytokines was also increased with MDP and LPS stimulation (P < 0.05). After silencing ASC, the secretion of IL-1β induced by MDP and LPS was significantly attenuated (P < 0.05).


CONCLUSION
In HPDLFs, MDP and LPS activated NLRP3 inflammasome and induced IL-1β secretion. ASC plays an important role in this inflammatory response.
['Lu|W L|WL|', 'Song|D Z|DZ|', 'Yue|J L|JL|', 'Wang|T T|TT|', 'Zhou|X D|XD|', 'Zhang|P|P|', 'Zhang|L|L|', 'Huang|D M|DM|']
D017209:Apoptosis D053468:CARD Signaling Adaptor Proteins D005347:Fibroblasts D006801:Humans D058847:Inflammasomes D007249:Inflammation D053583:Interleukin-1beta D015850:Interleukin-6 D000071199:NLR Family, Pyrin Domain-Containing 3 Protein D010513:Periodontal Ligament D014409:Tumor Necrosis Factor-alpha
NLRP3 inflammasome human periodontal ligament fibroblasts ASC inflammation