Investigating the Expression level of miRNA-21, miRNA-155, miRNA-182, and miRNA-437 along with Inflammatory Markers in Cerebrospinal Fluid of Patients with Multiple Sclerosis

Evidence suggests that microRNAs (miRNAs) are essential for immune cell differentiation and function. In addition, miRNAs play an essential role in regulating the expression of pro-inflammatory genes in neurons. Therefore, we investigated the relationship between miRNA expression and inflammatory markers in the CSF of patients with multiple sclerosis.

RT-PCR analysis was performed on CSF samples from patients with multiple sclerosis (MS) and a control group to measure the expression level of miRNA-21, miRNA-155, miRNA-182, and miRNA-437. In addition, the levels of the inflammatory cytokines including IL-1β, IL-6, and TNF-α in CSF were measured using ELISA. A quantitative turbidimetric method was also used to measure high-sensitivity C-reactive protein (hs-CRP).

A significant difference was found in the expression level of miRNAs and inflammatory factors in the CSF of patients with MS compared with the control group (p<0.05). The results of receiver operating characteristic (ROC) analysis showed the area under the curve for miRNA-21 (AUC=0.97, p<0.0001), miRNA-182 (AUC=0.97, p<0.0001), and miRNA-155 (AUC=0.96, p<0.0001). The miRNA-155 level in CSF played a very important role in the accurate diagnosis of MS. Significant correlations were found between inflammatory cytokines and miRNA-21, miRNA-155, and miRNA-182, as well as an indirect and moderate correlation between miRNA-437 and hs-CRP.

In MS patients, CSF levels of IL-1, IL-6, TNF-α, hs-CRP, and selected miRNAs can be used as biomarkers of CNS inflammation and neurodegenerative processes.