Analysis of promoter methylation in miR-145, miR-155, SHP-1 and PADI-2 genes in peripheral blood of patient with multiple sclerosis

Abstract

MS is a chronic autoimmune CNS disease characterized by inflammation and neurodegeneration that occurs in genetically susceptible hosts and is caused by a complex interaction of genetic and environmental factors and has a variable clinical course. A growing body of evidence supports the role of epigenetic processes in the underlying mechanisms of immune pathogenesis and nervous system dysfunction in MS. Epigenetic processes, such as DNA methylation and histone post-translational modifications, integrate the effects of genes and the environment to regulate gene expression. Studying epigenetic changes, which are stable and reversible, may provide an alternative approach to better understanding and managing disease. One of the genes that are methylated is miRNAs. It is thought that miRNAs play an important role in MS because they are expressed in a very large amount in immune cells. In addition to the involvement of microRNAs in the pathogenesis of MS, other important genes such as PTPN6 (SHP-1) and PADI-2 also play a role in MS. In the current project, our aim is to identify a series of functional methylation markers for the early diagnosis of MS, from by comparing the methylation level of these genes in the peripheral blood samples of patients and comparing it with the methylation of these genes in the peripheral blood of healthy people. Method: Among the patients with a definite diagnosis of MS who visited the doctor, 75 patients were randomly selected and blood samples were taken from them. In fact, sampling was done randomly. Genomic DNA was extracted from the samples using a DNA extraction kit. After DNA extraction and treatment with bisulfite, the methylation pattern of gene promoter was quantitatively determined by MS-HRM method. As a control group in this study, a number of 75 samples of healthy people who were similar to the study group in terms of biological characteristics were taken and analyzed. Results: In the patient group, the average methylation percentage of the miR-145 gene promoter region in MS patients has a significant increase compared to the control group (P value: 0.013). In addition, the results of the ROC curve for methylation showed that methylation changes in the investigated area with Pvalue: 0.015 have a biomarker value in the diagnosis of multiple sclerosis patients. Methylation in the promoter of miR-155 in MS patients has a significant increase compared to the control group. (Pvalue: 0.022). In addition, the results of ROC curve for methylation showed that methylation changes in the investigated area with Pvalue: 0.053 do not have a biomarker value in the diagnosis of multiple sclerosis patients. Methylation in PADI2 promoter is significantly increased in MS patients compared to the control group (Pvalue: 0.017). In addition, the results of ROC curve for methylation showed that methylation changes in the investigated area with Pvalue: 0.010 have biomarker value in the diagnosis of multiple sclerosis patients. The methylation rate of SHP-1 promoter in MS patients was not significantly different compared to the control group.