PLEIOTROPIC EFFECTS OF DNA METHYLATION MODULATORS ON RHEUMATOID ARTHRITIS SYNOVIAL FIBROBLASTS IN VITRO

To evaluate pleiotropic eff ects of DNA methylation modulators, we used cultures of fibroblast-like synoviocytes (FLS) obtained during total arthroplasty from nine rheumatoid arthritis (RA) patients. It was shown that addition of hydralazine to cultures lead to significant two-fold decrease in of global DNA methylation, whereas addition of donors of methyl group S-adenosyl L-methyonine (SAMe) and genistein resulted in reduction of 5-methylcytosine in FLS by 35%. There was a spontaneous production of IL-6, IL-17, IL-18, IL-10, and osteoprotegerin (OPG) by FLS, the stimulation with IL1β lead to significant increase of these cytokines synthesis. The production of pro-infl ammatory cytokines was reduced only after addition of SAMe to cultures in some doses. Demethylating agent hydralazine had no eff ect on cytokine synthesis, while genistein decreased production of IL-6 and IL-17 in some concentrations. The production of IL-10 was not changed by the modulators of DNA methylation. Addition of SAMe and genistein to cultures lead to significant reduction of OPG production while hydralazine did not have any eff ect on OPG synthesis. All three DNA methylation modulators significantly reduced migration and invasion of FLS in Boyden chambers. In conclusion, cytokine synthesis, migration and invasion of FLS are modulated not only by DNA methylation, but probably via other epigenetic mechanisms. The model of FLS cultures can be used for preclinical assessment of DNA methylation inhibitors.