Increased expression of mir-301a in PBMCs of patients with relapsing-remitting multiple sclerosis is associated with reduced NKRF and PIAS3 expression levels and disease activity.

Most of the multiple sclerosis (MS) patients are initially diagnosed with relapsing remitting multiple sclerosis (RRMS). Th17 cells and macrophages have been shown to play critical roles in pathogenesis of MS and initiation of CNS tissue damage. MiR-301a have recently been exposed as an activator of STAT3 in Th17 cells as well as an activator of NF-κB in macrophages by targeting PIAS3 and NKRF correspondingly. However, the possible role of miR-301a in RRMS has not yet been elucidated. Herewith, for the first time, we have studied the expression of miR-301a, NKRF and PIAS3 by quantitative real-time PCR and western blotting method in peripheral blood mononuclear cells (PBMCs) of 71 RRMS patients, including two groups of patients in relapse phase (n = 44) and a group of remitting phase patients (n = 28) in comparison to healthy volunteers (n = 28). In this work, we demonstrate a significant upregulation of miR-301a in relapse phase of MS patients compared to healthy controls and remitting phase patients (P < .05). Our findings also showed a striking decrease of NKRF and PIAS3 expression in relapse phase patients, in contrast to miR-301a and, NF-κB and STAT3 downstream genes (SKA2 and RORc) (P < .05). Subsequently, using luciferase reporter system we confirmed that miR-301a directly targets the mRNA encoding PIAS3 and NKRF proteins. We also showed that miR-301a increasing expression is correlated with down-regulation of PIAS3 and NKRF expression in RRMS patients. Our findings suggest that miR-301a, PIAS3 and NKRF play crucial roles in RRMS and could be considered as promising therapeutic targets.