MicroRNA-20a negatively regulates expression of NLRP3-inflammasome by targeting TXNIP in adjuvant-induced arthritis fibroblast-like synoviocytes

Objectives: Rheumatoid arthritis (RA) is a heterogenic and systemic autoimmune disease characterized by synovitis and joint structural damage. However, the pathogenesis of RA is still obscure. It has been reported microRNA-20a (miRNA-20a) was significantly associated with the regulation of pro inflammatory cytokines release in RA FLS. The purpose of this study was to explore the function and underlying mechanisms of miRNA-20a on NLRP3-inflammasome in adjuvant-induced arthritis (AA) fibroblast-like synoviocytes (FLSs) in vitro. Methods: In this study, using a combination of Western blotting, Q-PCR, and ELISA analysis, we investigated the influence and function of miRNA-20a on NLRP3-inflammasome by targeting TXNIP in AA FLSs. Results: In the present study, the expression of NLRP3-inflammasome was significant up-regulated in AA model in vitro. Our study indicated that silence of NLRP3 down-regulated the expression of NLRP3-inflammasome and the secretion of IL-1 beta and MMP-1. Moreover, over-expression of miR-20a decreased formation of NLRP3-inflammasome, including NLRP3, ASC and caspase-1, and suppressed the secretion of IL-1 beta and MMP-1, along with down-regulated the expressions of TXNIP in primary FLSs isolated from AA. With the combined use of prediction programs and luciferase assay, the rat TXNIP mRNA 3'UTR predicted to be targeted by miR-20a. Similarly, inhibitor TXNIP expression by TXNIP-siRNA markedly repressed formation of NLRP3-inflammasome and the secretion of IL-1 beta and MMP-1. Conclusion: Taken together, these results indicate that miR-20a may play a pivotal role in the NLRP3-inflammasome by targeted inhibit TXNIP expression in AA FLSs. (C) 2016 Societe francaise de rhumatologie. Published by Elsevier Masson SAS. All rights reserved.