Neutrophil-derived microRNA-1290 promotes keratinocyte proliferation in psoriasis

The pathological hallmark of psoriasis is the infiltration of neutrophils into the skin. Some neutrophil-derived microRNAs (miRNAs) serve as biomarkers for various diseases, but none have been reported for psoriasis. Here, we investigated the involvement of miRNAs released from neutrophils in psoriasis pathogenesis. We compared the expression of miRNAs in the sera of patients with psoriasis and healthy individuals and found that the expression of two miRNAs, miR-223 and miR-1290, was significantly upregulated in the sera of patients with psoriasis. The serum levels of these miRNAs positively correlated with the psoriasis area and severity index (PASI) and C-reactive protein level. We used all-trans retinoic acid to induce the differentiation of human promyelocytic leukemia HL-60 cells into neutrophil-like cells and found that the release of both miRNAs increased during differentiation. Furthermore, the release of miR-1290 was increased by tumor necrosis factor alpha (TNF-α) in neutrophil-like cells and human neutrophils. Treatment with the miR-1290 precursor promoted the proliferation of human keratinocytes, increased the proportion of S-phase cells, and upregulated the phosphorylation of ERK1/2. These results suggest that miR-1290 plays a vital role in regulating neutrophil differentiation and keratinocyte proliferation and could be a serum marker of psoriasis severity.