Identification of Potential Biomarkers in the Peripheral Blood Mononuclear Cells of Relapsing–Remitting Multiple Sclerosis Patients

Multiple sclerosis (MS) is described as an immune disorder with inflammation and neurodegeneration. Relapsing-remitting MS (RRMS) is one of the most common types of MS. The diagnostic manner for this disorder typically includes the usage of magnetic resonance imaging (MRI); however, this is not always a very precise diagnostic method. Identification of molecular biomarkers in RRMS body fluids samples compared to healthy subjects can be useful to indicate the normal and pathogenic biological processes or pharmacological responses to drug interaction. In this regard, this study evaluated different miRNAs in isolated peripheral blood mononuclear cells (PBMCs) of RRMS compared to controls and their correlations with altered T regulatory type 1 (Tr1) cells, osteopontin (OPN), and interleukin 10 (IL-10) levels. The frequency of Tr1 cells was measured using flow cytometry. Also, the expressions of different miRNAs were evaluated via quantitative real-time polymerase chain reaction (RT-qPCR) and plasma levels of IL-10 and OPN were tested by enzyme-linked immunosorbent assay (ELISA). The obtained results showed the Tr1 cells' frequency, Let7c-5p, and miR-299-5p levels decreased in RRMS patients to about 59%, 0.69%, and 20% of HCs, respectively, (P < 0.05). The miR-106a-5p levels increased about 7.5-fold in RRMS patients in comparison to HCs (P < 0.05). Moreover, the results showed that there was an increased negative association between Tr1 frequency and plasma-OPN levels in RRMS patients in comparison to HCs and also, we found a moderate positive correlation between plasma-IL-10 and miR-299-5p expression of RRMS patients. Overall, it may be possible to use these biomarkers to improve the diagnostic process. These biomarkers may also be considered for clinical and therapeutic studies in the future.