Multiple sclerosis (MS) is an inflammatory, autoimmune demyelinating, and neurodegenerative disorder of the central nervous system. Interactions between environmental factors, predisposition genes, and determining genes appear to be involved in its etiology. Epigenetic mechanisms such as microRNA-mediated gene regulation can determine the susceptibility and severity of autoimmune diseases. Therefore, to determine the role of miR-146a and miR-155 in MS and its developmental stages, the expression levels in the serum of MS and clinically isolated syndrome (CIS) patients were compared with those of healthy controls. In the present study, the expression levels of miR-146a and miR-155 were assessed using quantitative Real-Time PCR in blood samples of 15 CIS patients and 61 relapsing-remitting multiple sclerosis (RRMS) patients alongside 32 healthy patients as controls. Furthermore, any associations with the clinicopathologic variables of the patients were also evaluated. Dysregulations were found only in the miR-146a and miR-155 expressions in the RRMS-Control group. When the RRMS patients were evaluated in terms of the characteristics of sex, annual attack rate, age of diagnosis, duration of follow-up, and immunomodulatory treatments used, no significant differences were observed. However, significant dysregulations were identified in miRNA expression in the vitamin D level, EDSS values, and the number of attacks. ROC curve analysis showed that miR-146a and miR-155 were significant in the RRMS-Control group for the area under the curve (AUC). It is possible that miR-146a may be associated with vitamin D deficiency and disease disability, while miR-155 may be associated with the number of attacks.
Keywords: Multiple sclerosis; clinically isolated syndrome; miR-146a; miR-155.