Increased Expression of miR-202-3p in Patients with Relapsing-Remitting Multiple Sclerosis

Background and objectives: One of the latest studies in the genetics field is the evaluation of role of micro-RNAs as a biomarker for diagnosis of multiple sclerosis (MS), which is a demyelinating disease of the central nervous system (CNS) and emerges in the form of numerous small and large plaques in white matter in the brain and spinal cord. This disease could be associated with several complications, including reduced vision, spasticity and imbalance, and impaired sphincter control. MiR-202-3p is an intronic miRNA located in the ADA (Adenosine Deaminase) gene, which is the main enzyme involved in the pathway for the conversion of adenosine into inosine. Moreover, ADA regulates the inflammatory response and protection of tissue from damage as a strong complementary mechanism. This study aimed to evaluate the expression level of miR-202-3p in individuals diagnosed with relapsing-remitting multiple sclerosis (RRMS) and healthy individuals in Isfahan, Iran.   Methods: This analytical-observatory study was performed on 49 RRMS patients and 52 healthy individuals with no history of autoimmune and inflammatory diseases. Total RNA was extracted from blood lymphocytes by Ficoll and Trizol. Afterwards, cDNA was formed using a special miRNA cDNA kit, followed by the application of Real-time RT PCR to measure the expression of miR-202-3p in healthy individuals and patients.   Results: According to the results, the miR-202-3p expression was higher in patients, compared to healthy individuals (P=0.006). In addition, the sensitivity and diagnostic value of this miRNA in receiver operating characteristic (ROC) curve analysis were equal to AUC=0.80 (area under the curve).   Conclusion: In line with other studies, our findings demonstrated that miR-2023p can be used as a biomarker in the diagnosis of MS. In addition, it seems that miR-202-3p acts as an immunosuppressant by inhibiting ADA gene, which regulates various processes related to inflammatory response and maintenance of tissue from damage.