Circ_0083964 knockdown impedes rheumatoid arthritis progression via the miR-204-5p-dependent regulation of YY1

Rheumatoid arthritis (RA) is a chronic inflammatory disease. Abnormal proliferation and inflammation of fibroblast-like synoviocytes (FLSs) are the main pathological features of the disease. Accumulating studies have identified that circular RNAs (circRNAs) were involved in the progression of RA. Our study was to assess the function and mechanism of circ_0083964 in RA. Quantitative real-time polymerase chain reaction (qRT-PCR) and western blot were utilized to test the level of circ_0083964, miR-204-5p and YY1. Counting Kit-8 (CCK-8) assay, EdU assay, flow cytometry, transwell assay and wound-healing assay were utilized to test cell viability, proliferation, apoptosis, invasion and migration. Cell inflammation was estimated with enzyme-linked immunosorbent assay (ELISA) kits. Dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay were employed to identify the target relationship between miR-204-5p and circ_0083964 or YY1. Circ_0083964 was highly expressed in RA synovial tissues and RA-FLSs. Circ_0083964 downregulation constrained proliferation, metastasis and inflammation and facilitated apoptosis in RA-FLSs. Furthermore, circ_0083964 served as a sponge of miR-204-5p, and rescue experiments proved that miR-204-5p deficiency overturned the suppressive impacts of circ_0083964 silencing on RA-FLSs progression. Additionally, we also verified that YY1 could be targeted by miR-204-5p, and its overexpression rescued the repressive impact of miR-204-5p introduction on RA-FLSs development. Besides that, we revealed that circ_0083964 mediated YY1 expression by regulating miR-204-5p. Circ_0083964 inhibition confined RA development by sponging miR-204-5p to hamper the YY1 level, which will provide a theoretical basis for the treatment of RA.