Heat Map-Based Analysis of miRNA Expression for Biomarker Identification in Inflammatory Polyneuropathy

Abstract

Polyneuropathy (PN) is a common nerve disorder that affects the peripheral nerves. PN are characterized by symmetrical and diffuse damage to the peripheral nervous system, potentially affecting motor, sensory, or autonomic nerve fibers. The disease may manifest with muscle weakness, atrophy, paresthesia, pain, decreased and autonomic symptoms. MiRNAs are small, non-coding RNA molecules, about 20-24 nucleotides long, that play a crucial role in the regulation of gene expression. MiR-146a and miR-31 are linked to immune inflammatory diseases and it plays an important role in controlling T and B lymphocytes and dendritic cells. These miRNAs may affect inflammatory mediators that promote or inhibit the immune response. The aim of this study was to perform a heatmap analysis to compare the expression of miR-31-5p and miR-146a-5p between patients with Chronic Inflammatory Demyelinating Polyneuropathy (CIDP) and Multifocal Motor Neuropathy (MMN) and controls. RNA was isolated from blood using mirVana™ miRNA Isolation Kit (ThermoFisher (TF), USA). The cDNR synthesis was performed using the TaqMan® Advanced miRNA cDNA Synthesis Kit (TF, USA). MiRNAs expression was detected by using qRT-PCR method. Results were analyzed using the heat-map method. The significance of the results was assessed using the SPSS Statistics 29.0.2.0. A total of 23 patients with CIDP/MMN and 56 controls were analyzed for miRNA expression in blood. The intensity and gradient of the colors in the heat map indicated the miRNA expression levels and revealed potential differences between CIDP/MMN patients and controls. Heatmap analysis can provide an overview of the miRNA expression profile between the CIDP and MMN subjects and the control group and help identify potential miRNA diagnostic markers.