In the present study, we investigated the role of nucleotide oligomerization domain-like receptor family pyrin domain containing 6 (NLRP6) in rheumatoid arthritis (RA) and explored the underlying mechanism. We found that both mRNA and protein levels of NLRP6 are attenuated in synovial tissues and fibroblast-like synoviocytes (FLS) of RA patients compared to patients with osteoarthritis. We also observed that pro-inflammatory cytokine production is decreased and nuclear factor-kappa B activation is inhibited in NLRP6-overexpressing RA-FLS. Furthermore, we found that NLRP6 overexpression promotes transforming growth factor-b-activated kinase 1-binding protein 2/3 lysosome-dependent degradation, and we provide evidence showing that NLRP6 plays the role of providing the docking site to facilitate the interaction between transforming growth factor-b-activated kinase 1-binding protein 2/3 and tripartite motif 38 in RA-FLS.
KEYWORDS: NF-κB, NLRP6, TAB2/3, fibroblast-like synoviocytes, rheumatoid arthritis