Tripartite motif 31 alleviates IL-1ß secretion via promoting the ubiquitination of pyrin domain domains-containing protein 3 in human periodontal ligament fibroblasts.

Apical periodontitis (AP) is an inflammatory disease caused by bacteria infection and is regarded as a common disease in the world. In the progression of AP, the function of nucleotide-binding oligomerization, leucine-rich repeat and pyrin domain domains-containing protein 3 (NLRP3) inflammasome has been revealed. Although tripartite motif 31 (TRIM31) has been suggested to regulate many chronic inflammations by mediating NLRP3 inflammasome, such mechanism in AP remains unclear. In this study, co-treatment of human periodontal ligament fibroblasts (HPDLFs) with lipopolysaccharides (LPS) and adenosine triphosphate (ATP) were conducted to establish AP cell model. ELISA assay was used to measure the concentration of secretive interleukin 1 beta (IL-1β). In addition, the expression levels of NLRP3 after TRIM31 up- or down-regulation were detected by real-time PCR and western blot. Immunoprecipitation was used to explore the interaction between TRIM31 and NLRP3. We found that co-treatment with LPS and ATP increased the secretion of IL-1β and expression of NLRP3 in HPDLFs, while TRIM31 overexpression could reverse these effects caused by LPS and ATP. Furthermore, the interaction between TRIM31 and NLRP3 was observed, and TRIM31 was found to promote the ubiquitination of NLRP3. TRIM31 may alleviate IL-1ß secretion caused by LPS and ATP via promoting the ubiquitination of NLRP3 and may exert an influence on the development of AP.