Impact of miR-155 Gene Polymorphism (rs767649 A>T) and miR-155 Gene Expression on Susceptibility to Multiple Sclerosis

Abstract

Background: Micro RNA155 (miR-155) was identified as an essential determinant in immunological responses, and its genetic variants have increasing attention due to their ability to modulate its expression and potentially influence the susceptibility to autoimmune illnesses including rheumatoid arthritis, systemic sclerosis, systemic lupus erythematosus, etc. Objectives: To examine the impact of miR-155 gene polymorphism (rs767649A>T) and miR-155 gene expression and their association with multiple sclerosis (MS) in a sample of Iraqi patients. Materials and methods: A total of 75 blood specimens were obtained from individuals diagnosed with MS. While an additional 75 blood specimens were collected from evidently healthy participants serving as a control group, with an age ranged 20-71 years. miR-155 gene polymorphism (rs767649 A>T) was determined utilizing Tetra-ARMS Polymerase Chain Reaction (Tetra-ARMS PCR) and miR-155 expression was evaluated using Real-time Polymerase Chain Reaction (RT-PCR). Results: The females experienced MS at a higher rate (69.33%) compared to the males. Furthermore, the age group 30-39 years showed a greater susceptibility to the disease (54.67%). The analysis of miR-155 (rs767649 A>T) SNP in MS patients indicated that 7 (9.34%) had the wild genotype (AA), 31 (41.33%) had the heterogeneous genotype (AT), and 37 (49.33%) had the mutant genotype (TT). These differences were statistically significant (P-value = 0.040). A allele frequency was 45 (0.3) (OR: 0.25; CI: 0.15-0.41) and T allele frequency was 105 (0.7) (OR: 3.91; CI: 2.42-6.33) in MS patients. While analysis of miR-155 gene expression demonstrated a significant increase in the patient group (1.82 ± 0.25 fold) compared to the healthy control group (0.33 ± 0.13 fold). The relationship between miR-155 gene expression and miR-155 genotypes in MS patients, revealed a notable elevation in miR-155 gene expression at the TT genotype (3.15 ± 0.73 fold), followed by TA genotype (1.29 ±0.65fold) and finally AA genotype (0.37 ± 0.19 fold) with highly statistically significant difference (P-value = 0.001). Conclusion: There was a significant positive correlation between miR-155 (rs767649 A>T) genotypes and miR-155 expression and susceptibility to MS in Iraqi patients. These findings suggests that miR-155 may hold potential as a diagnostic and therapeutic marker for the disease.