Association of circulating miRNA-21-5p and miRNA-146a-5p expression level with disease activity of ankylosing spondylitis

Abstract

BackgroundThe etiopathogenesis of ankylosing spondylitis (AS) involve interaction between genetic and environmental factors which exert an effect on epigenetic mechanisms including non-coding miRNAs causing immune dysfunction and inflammation. This study is designed to find if there is an association in the expression levels of miRNA- 21-5 (miR-21-5p) and miR- 146a-5p with the disease activity, also to assess their role in the follow up of patients. MethodSixty individuals enrolled in this case-control study; 30 individual (28 males and 2 females) as patients group, and the healthy controls group include 30 individuals (27 males and 3 female). Twenty four patients were human leukocyte antigen (HLA B-27) positive, while the other 6 patients were negative. Reverse transcription polymerase chain reactions (RT- PCR) was used for determination of the expression levels of miRNA-21-5p and miRNA-146a-5p in serum of patients and controls, while concentration of high sensitivity C- reactive protein (HS- CRP) was estimated using enzyme linked immune-sorbent assay (ELISA). These tests were done two times for each patient; the first is before starting biologic treatment and the second after two months from taking the first dose. ResultsThere are significant elevations (p < 0.001) in the expression of miR- 21-5p and miR- 146a-5p also in the serum level of Hs-CRP in patients compared with controls. In patient group, miR-21-5p expression is significantly reduced at end of the study (p value <0.05), while there is no significant difference (p > 0.05) of miR-146-5p expression between baseline and end of the study. At base line of the study; it is found that the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) and Bath Ankylosing Spondylitis Functional Index (BASFI) scores and Hs-CRP were positively correlated with both of miR- 146a-5p and miR- 21-5p and the correlation remain positive at in the end of study. In conclusion, expression level of circulating miR-21-5p and miR-146a-5p could be serve as non invasive biomarkers for the diagnosis of AS. Micro-RNA-21-5p associated with the activity and severity of the disease and it could be used for follow up patients with AS and for assessment the response to biological treatments.