Expression levels and IFGN RS2069727 T/C single nucleotide polymorphism with clinical and in silico approaches in the scope of MS risk and glatiramer acetate treatment

Multiple sclerosis (MS) is a chronic autoimmune chronic disease of the central nervous system (CNS). The most common clinical type is relapsing-remitting MS (RRMS). Interferon-gamma (IFN-gamma) has important roles in the inflammatory pathway observed in MS. Variations in the IFNG gene and some microRNAs (miRNAs) affect the expression of IFN-gamma. The IFNG rs2069727 T/C variation with MS was investigated for the first time in the Turkish population in this study. Moreover, in our study, the plasma IFN-gamma levels, the IFNG rs2069727 T/C variation thought to affect these levels, and the relative expression levels of hsa-miR-24-3p and hsa-miR-181d-3p were examined for their effects on MS risk and disability scores. The IFN-gamma protein level and the relative expression levels of hsa-miR-24-3p and hsa-miR-181d-3p, which are thought to influence this level, were evaluated together for the first time in terms of RRMS diagnosis and response to glatiramer acetate (GA) treatment. In this study, two overlapping groups, the "genetic polymorphism study group" and the "miRNA and ELISA study group", were formed according to the 2017 McDonald Revised Criteria. The genetic polymorphism group included 330 RRMS patients and 330 controls. This group included 25 RRMS patients who had not started GA treatment (treatment-naïve), 25 RRMS patients who received GA treatment, and 25 controls in the miRNA and ELISA study section. Genotyping of MS patients in the genetic polymorphism study group was performed by real-time polymerase chain reaction. Plasma hsa-miR-24-3p and hsa-miR-181d-3p relative expression levels in the miRNA and ELISA study group participants were determined by quantitative real-time PCR, and plasma IFN-gamma levels were determined by ELISA method. Samples were taken from Ankara Bilkent City Hospital Neurology Polyclinic. The IFNG rs2069727 T/C variation was analyzed among the groups, and no significant differences were observed in genotype distributions. Plasma relative expression analysis revealed that hsa-miR-24-3p and hsa-miR-181d-3p levels were significantly higher in GA and treatment-naïve patients compared to the control group; whereas age-adjusted plasma IFN-gamma levels were significantly lower in GA and treatment-naïve patients compared to controls. In the overall group analysis, individuals with low IFN-gamma levels (≤1.311pg/mL) had significantly higher hsa-miR-24-3p relative expression levels compared to those in the high IFN-gamma group (>1.311pg/mL). Additionally, individuals with low hsa-miR-181d-3p levels (≤ 2.90) had significantly higher plasma IFN-gamma levels compared to those with high hsa-miR-181d-3p levels (>2.90). In this study, the network of miRNAs and transcription factors regulating the IFNG gene was created by in silico analysis. Furthermore, an interaction has been identified between hsa-miR-24-3p and genes associated with GA therapy, specifically within the C-type lectin domain family 16 member A and cathepsin S. This thesis is a study that makes significant contributions to the field of Biomedical Engineering by developing new potential diagnostic tests, which may be used in novel biosensors in the future, thereby facilitating the easier early diagnosis and prognosis monitoring of RRMS, and by conducting new studies that evaluate hsa-miR-24-3p and hsa-miR-181d-3p as drug targets for the treatment of RRMS.