The role of regulatory micro-RNAs in inflammatory processes and production of tumor necrosis factor-alpha in patients with rheumatoid arthritis

Abstract

Background. Micro-RNAs are fundamental agents of post-transcriptional control of gene expression. In recent years many works have appeared on the possible role of micro-RNAs in rheumatoid arthritis (RA). Studies of the role of micro-RNA and the relationship with the synthesis of tumor necrosis factor-α (TNF-α) are very promising for understanding the pathogenesis and treatment of RA and other autoimmune diseases. The purpose of the research was to study the role of regulatory micro-RNAs in inflammatory processes and the possible connection with the production of TNF-α in patients with RA. Materials and methods. 29 patients with active RA and 20 healthy individuals (control) were examined. All subjects were examined for 16 micro-RNAs. The choice of micro-RNA was based on previous studies and theoretical conclusions (according to the ­miRWalk database). Rheumatoid factor, the level of antibodies to cyclic peptides containing citrulline, C-reactive protein (СRP), le­vels of TNF-α (serum, spontaneous, and stimulated) were determined in the blood of patients. Results. Statistical analysis de­monstrated significant overexpression of miR-221, miR-203, miR-146b, miR-132, ­miR-21 and miR-17-3p and inhibition of miR-223 synthesis in RA patients. The activation of TNF-α synthesis at rest and the increased production of TNF-α by mononuclear cells after stimulation in RA were shown. Differences in the levels of relative expression of some micro-RNAs between seropositive and seronegative groups of RA patients were found, but only hyperexpression of miR-155 was highly reliable. For the first time, a possible relationship between TNF-α production and miR-29 and miR-155 micro-RNAs, as well as a correlation between miR-16, miR-99b and miR-203 and CRP levels, was revealed. Conclusions. The obtained data on the profile of micro-RNAs in RA makes it possible to distinguish the most “interesting” micro-RNAs for further study of pathogenesis, their role in inflammation, to study the choice of TNF-α inhibitors, and predicting the effectiveness of that treatment.