Upregulation of the miRNA-155, miRNA-210, and miRNA-20b in psoriasis patients and their relation to IL-17.

Psoriasis is an immune-mediated disease, with genetic background and triggering environmental factors; however, several gaps are still present in understanding the intertwined relationship between these elements. Epigenetic mechanisms, including microRNAs (miRNAs), play an important role in the pathogenesis of psoriasis. The relationship between interleukin (IL)-17, a key cytokine in psoriasis, and these epigenetic mechanisms still needs to be elucidated. This study aimed at assessing the expression of miRNA-155, miRNA-210, and miRNA-20b in skin and sera of psoriasis patients in relation to IL-17 levels. For 20 psoriasis patients and 20 matching controls, the expression of miRNA-155, miRNA-210, and miRNA-20b was assessed using real-time polymerase chain reaction (RT-PCR), whereas IL-17/IL-17A levels were measured using quantitative enzyme-linked immunosorbent assay (ELISA) technique. MiRNA-155 expression was significantly higher in lesional skin compared to controls (P = 0.001). MiRNA-210 expression was significantly higher in both, lesional skin (P = 0.010) and sera of patients (P = 0.001) in comparison with controls. A statistically significant positive correlation was found between serum miRNA-210 expression and serum levels of IL-17/IL-17A (P = 0.010, rs = 0.562). MiRNA-20b lesional and non-lesional expression was significantly higher than controls (P < 0.001; P = 0.018). In conclusion, the expression of miRNA-155, miRNA-210, and miRNA-20b is exaggerated in psoriasis and they may be involved in disease pathogenesis. A possible relationship between miRNA-210 and IL-17 may be suggested; however, further studies are still needed to verify this relation.