SIRT1 is transcriptionally repressed by YY1 and suppresses ferroptosis in rheumatoid arthritis

ABSTRACT

Abstract Background Sirtuin 1 (SIRT1) is reported downregulated in rheumatoid arthritis (RA), and the protective effects of SIRT1 on tissue damage and organ failure may be related to cellular ferroptosis. However, the exact mechanism by which SIRT1 regulates RA remains unclear. Methods Quantitative real-time PCR (qPCR) and western blot assays were performed to explore the expressions of SIRT1 and Yin Yang 1 (YY1). CCK-8 assay was used for cytoactive detection. The interaction between SIRT1 and YY1 was validated by dual-luciferase reporter gene assay and chromatin immunoprecipitation (ChIP). DCFH-DA assay and iron assay were applied to detect the reactive oxygen species (ROS) and iron ion levels. Results In the serum of RA patients, SIRT1 was downregulated, but YY1 was upregulated. In LPS-induced synoviocytes, SIRT1 could increase cell viability and decrease ROS and iron levels. Mechanistically, YY1 downregulated the expression of SIRT1 by inhibiting its transcription. YY1 overexpression partly revised the effects of SIRT1 on ferroptosis in synoviocytes. Conclusion SIRT1 is transcriptionally repressed by YY1 and inhibits the ferroptosis of synoviocytes induced by LPS, so as to relieve the pathological process of RA. Therefore, SIRT1 might be a new diagnosis and therapeutic target of RA. Highlights Combining SIRT1 with synoviocytes ferroptosis in rheumatoid arthritis for the first time. The transcription factor YY1 combined to the SIRT1 promoter in synovial cells and inhibited its expression and functional roles. The inhibition of SIRT1 with YY1 decreased the ferroptosis in synoviocytes.