ACPAs promote IL-1beta production in rheumatoid arthritis by activating the NLRP3 inflammasome.

X. Dong et al.
Cellular molecular immunology 2019 mar

Abstract

OBJECTIVES Anti-citrullinated protein antibodies (ACPAs) are a group of autoantibodies targeted against citrullinated proteins/peptides and are informative rheumatoid arthritis (RA) biomarkers. ACPAs also play a crucial role in RA pathogenesis, and their underlying mechanism merits investigation. METHODS Immunohistochemical (IHC) assays were carried out to determine IL-1beta levels in ACPA+ and ACPA- RA patients. PBMC-derived monocytes were differentiated into macrophages before stimulation with ACPAs purified from RA patients. The localization and interaction of molecules were analyzed by confocal microscopy, co-IP, and surface plasmon resonance. RESULTS In our study, we found that IL-1beta levels were elevated in ACPA+ RA patients and that ACPAs promoted IL-1beta production by PBMC-derived macrophages. ACPAs interacted with CD147 to enhance the interaction between CD147 and integrin beta1 and, in turn, activate the Akt/NF-kappaB signaling pathway. The nuclear localization of p65 promoted the expression of NLRP3 and pro-IL-1beta, resulting in priming. Moreover, ACPA stimulation activated pannexin channels, leading to ATP release. The accumulated ATP bound to the P2X7 receptor, leading to NLRP3 inflammasome activation. CONCLUSIONS Our study suggests a new hypothesis regarding IL-1beta production in RA involving ACPAs, which may be a potential therapeutic target in RA treatment.