AB0037 APE1 REGULATES THE MIGRATION OF FIBROBLAST-LIKE SYNOVIOCYTES FROM PATIENTS WITH RHEUMATOID ARTHRITIS

Abstract

BackgroundThe level of apurinic/apyrimidinic endonuclease 1 (APE1) is elevated in synovial fluids from patients with rheumatoid arthritis (RA). However, the role of APE1 in RA pathogenesis remains unclear.ObjectivesTo explore whether APE1 affects cell migration through reactive oxygen species (ROS) level, fibroblast-like synoviocytes (FLS) from patients with RA were stimulated with human recombinant APE1.MethodsSynovial tissues were obtained from RA patients who were undergoing synovectomy or joint replacement. The isolated cells were cultured in Dulbecco’s modified Eagle’s medium (DMEM) supplemented with 10% fetal bovine serum and maintained in a 5% CO2 incubator at 37 °C. FLS were used for experiments after three to six passages. Cells were stimulated with or without recombinant interleukin 17 (IL-17; 10 ng/ml), tumor necrosis factor alpha (TNF-α; 10 ng/ml), and long-lasting recombinant human APE1 (MR201; 1, 10, 100 ng/ml) for 24 h. ROS levels were analyzed using MitoSOX dye. Cell migratory ability was examined using wound migration assay.ResultsRA FLS treated with APE1 showed slightly decreased level of mitochondrial specific ROS. To induce pro-inflammatory conditions, RA FLS were incubated with IL-17 and TNF-α. These cytokines are highly detected in RA synovium and directly stimulate FLS activation. Stimulation with IL-17 and TNF-α upregulated ROS by 30% compared to control. Cytokines-induced increase of ROS was inhibited by 22% in APE1 treatment. When FLS cultures were approximately 90% confluent, FLS monolayers were wounded with pipette tips and treated with IL-17/TNF-α and APE1 for 24 h. Cell migration was increased after treatment with IL-17/TNF-α. Cytokines-induced cell migration was remarkably attenuated by APE1 treatment.ConclusionRecombinant APE1 markedly inhibited mitochondrial specific ROS production and IL-17/TNF-α-induced cell migration in RA FLS.