Increased serum levels of miR-1266 in patients with psoriasis vulgaris.

MicroRNAs (miRNAs) are post-transcriptional regulators that bind to complementary sequences in the 3' UTRs of mRNAs, leading to gene silencing, and their serum levels can be useful biomarkers for diagnosis, prognosis and therapeutic value in various diseases. Although miRNAs are thought to be involved in the pathogenesis of human diseases, little is known about miRNAs in psoriasis. Recently, psoriasis has attracted attention for its characteristics as a Th17 disease; the expression of IL-17 is increased in lesional skin and serum. We hypothesized that miRNAs contribute to the mechanism underlying the overexpression of IL-17. Therefore, serum levels of miR-1266, a putative regulator of IL-17A, in psoriasis patients were determined with the expectation that miR-1266 levels may be decreased in these patients, which may result in induction of IL-17. However, real-time PCR demonstrated that serum miR-1266 levels were considerably higher in psoriasis patients than in healthy control subjects. Furthermore, miR-1266 levels showed weak inverse correlations with Psoriasis Area Severity Index scores and body surface areas of involved skin. Taken together, serum miR-1266 may have potential for a new disease marker. miR-1266 is not likely to regulate IL-17A expression directly, but may be involved in the pathogenesis of psoriasis by regulating other target molecules.