Paeoniflorin inhibits the inflammation of rheumatoid arthritis fibroblast-like synoviocytes by downregulating hsa_circ_009012.

ABSTRACT

Background: Rheumatoid arthritis (RA) is a chronic inflammatory disease that leads to progressive joint damage. Circular RNA (circRNA) can regulate the inflammatory response of fibroblast-like synoviocytes (FLSs) in RA, influencing the disease progression. Paeoniflorin (PF) is the main active ingredient extracted from Paeonia lactiflora and is known for its anti-inflammatory effect. This study aims to explore the potential mechanisms by which hsa_circ_009012 and PF regulate the inflammatory response in RA. Methods: RNA expression of hsa_circ_009012, has-microRNA-1286 (miR-1286), toll-like receptor 4 (TLR4), NOD-like receptor thermal protein domain associated protein 3 (NLRP3) was assessed by real-time quantitative polymerase chain reaction (RT-qPCR) or western blotting (WB). Cell inflammation markers (TNF-α, IL-1ß, IL-6) were assessed by RT-qPCR and immunofluorescence (IF). Counting Kit-8 (CCK-8) assay, flow cytometry, and transwell assay were utilized to test cell viability, cell cycle distribution, and migration. Results: Hsa_circ_009012 was highly expressed in RA-FLS. Hsa_circ_009012 over-expression facilitated the inflammation in RA-FLS and was closely associated with the miR-1286/TLR4 axis. Paeoniflorin inhibited inflammation and the expression of hsa_circ_009012 and TLR4, while upregulating the expression of miR-1286 in RA-FLS. Moreover, the upregulation of hsa_circ_009012 reversed the repressive effect of paeoniflorin on RA-FLS progression. Conclusion: Paeoniflorin inhibits the inflammation of RA-FLS via mediating the hsa_circ_009012/miR-1286/TLR4/NLRP3 axis.