Up-regulated serum miR-128-3p in progressive and relapse-free multiple sclerosis patients

Background: Circulating microRNAs have emerged as novel multiple sclerosis (MS) biomarkers. Aims: To assess the association between candidate miRs expression in serum samples of patients with MS and the disease course. Methods: Serum levels of ten microRNAs (i.e. miR-199, miR-128-3p, miR-20a-5p, miR-27a-3p, miR-15b-5p, miR-325, miR-92a1-5p, miR-223-5p, miR-22-5p, and miR-23a-5p) were measured in 74 MS cases and 17 non-MS controls consecutively enrolled at Verona University Hospital. The association of microRNAs expression with patients' clinical and MRI features was analyzed. Candidate microRNAs were detected by Real-Time PCR and expressed as ratio of each microRNA level to a normalizer. Results: Serum miR-128-3p levels were higher in progressive than relapsing MS (median ratio 2.86 vs 0.73, p=0.036). In addition, miR-128-3p was up-regulated in patients without relapses after sample collection compared to cases who relapsed (1.64 vs 0.82; p=0.014). miR-128-3p levels and relapse rate were inversely correlated (r= -0.44, p=0.008). Conclusions: Serum levels of mir-128-3p could be related to biological mechanisms underlying MS activity and progression.