LncRNA NEAT1 regulates the proliferation and production of the inflammatory cytokines in rheumatoid arthritis fibroblast-like synoviocytes by targeting miR-204-5p.

Rheumatoid arthritis (RA) is a chronic inflammatory disease, featured by erosive arthritis, which will eventually lead to deprivation normal functions of the joint and joint malformations. Continued illness also results in more serious complications, such as cardiovascular diseases and disability. Long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) function in various conditions, including RA. LncRNA NEAT1 was reported to promote migration and invasion in RA-FLSs, functioning as a promising diagnostic and therapeutic indicator in RA. The present work focused on the role of lncRNA NEAT1 in RA and the related mechanism. We collected the synovial tissue samples of 30 RA patients and 20 healthy controls. Moreover, RA fibroblast-like synoviocytes (RA-FLSs) cell line was bought and treated with tumor necrosis factor-α (TNF-α) to establish in vitro model of RA. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to determine the expression of NEAT1 in synovial tissue and RA-FLSs. NEAT1 silencing plasmid were synthesized and co-trasnfected with miR-204-5p inhibitor into RA-FLSs. MTT and 5-Ethynyl-2'-deoxyuridine staining were used to assess cell proliferation. Flow cytometry and TUNEL assay were used to determine the cell apoptosis. miR-204-5p has been predicted as a target miRNA of NEAT1, and the interaction between NEAT1 and miR-204-5p was verified by dual-luciferase assay and RNA pull-down assay. qRT-PCR and enzyme-linked immunosorbent assay were used to determine the mRNA and protein concentration of interleukin-1β and interleukin-6. Finally, western blot assay was applied to measure the effect of NEAT1 and on p53, NF-κB, and p-NF-κB expressions. We found that NEAT1 was up-regulated, and miR-204-5p was down-regulated in the RA patients' synovial tissue and TNF-α treated RA-FLSs. TNF-α increased NEAT1 level and decreased miR-204-5p level in RA-FLSs. There was no significant variance of p53 after transfected with NEAT1 in RA-FLSs. Meanwhile, Knockdown of NEAT1 attenuated TNF-α-induced RA-FLSs cell proliferation and inflammatory cytokine production while promoted cell apoptosis by targeting miR-204-5p through NF-κB pathway. These findings indicated that NEAT1 may be developed as a potential target for patients with RA.