The Expression and Potential Role of Micro RNAs in Oral Lichen Planus

BACKGROUND: Oral lichen planus (OLP) is a chronic T-cell-mediated immune disease of unknown aetiology. MicroRNA (miRNAs) are short non-coding RNAs capable of regulating mRNA and may have roles in T-cell-related diseases. The aim of this study was to investigate the profile of miRNAs in OLP patients and its interaction with potential target genes. METHODS: Total RNA was extracted from fresh frozen biopsies from 24 patients with OLP and 8 control patients. The NanoString Counter Analysis System was used to analyse total RNA samples for differential miRNA expression. NanoString expression was confirmed by RT-qPCR analysis. Genes potentially targeted by upregulated and downregulated miRNAs were identified, and RT-qPCR was employed to investigate the expression of target genes in OLP and controls. Probability values < 0.05 were considered statistically significant. RESULTS: NanoString analysis showed that eight miRNAs, miR-155, miR-146a, miR-3195, miR-342, miR-4516, miR-21, miR-29a and miR-193 were upregulated in OLP tissues. Contrarily, the other eight miRNAs, miR-221, miR-200b, miR-149, miR-205, miR-27b, miR-95, miR-127b, miR-95, miR-206 were downregulated in OLP tissues. NanoString findings have been confirmed by RT-qPCR results for four upregulated miRNAs, miR-155, miR-146a, miR-29a and miR-342, and one downregulated miRNA, namely miR-205. The expression of two target genes, namely MYC for miR-29a and interleukin-24 (IL-24) for miR-205, was found to negatively correlate with the respective miRNA. This suggests that MYC and IL-24 could be regulated by the above miRNAs in OLP. CONCLUSIONS: The work presented in this study suggests that miRNAs could be involved in both the immunopathogenesis and malignant transformation of OLP.