MicroRNA-223 affects IL-6 secretion in mast cells via the IGF1R/PI3K signaling pathway

: In this study, we aimed to assess the effects of microRNA-223 (miR-223) on interleukin-6 (IL-6) secretion in mast cells and determine the underlying molecular mechanisms. Mast cells (P815) were transfected with miR-223 lentiviral vector and miR-223 inhibitor. miR-223 expression was then evaluated using reverse transcription-quantitative PCR (RT-qPCR). IL-6 levels in the supernatant were analyzed using enzyme-linked immunosorbent assay. The signaling pathways in mast cells with downregulated miR-223 were initially evaluated by gene chip. Downregulation of miR-223 and its target gene was tested using a luciferase reporter assay. The expression of phosphate-AKT (p-AKT) and its target protein insulin-like growth factor-1 receptor (IGF1R) was assessed by western blot analysis. Phosphatidylinositol 3-kinase (PI3K)-inhibitor (LY294002) and insulin-like growth factor-1 (IGF1) were used to determine the effect of miR-223 on IL-6 secretion in mast cells. The results showed that microRNA-223 reduced IL-6 concentration in the mast cells. The gene chip results predicted an induction of the PI3K-AKT signaling pathway in the mast cells. Luciferase reporter assay confirmed IGF1R gene to be a target of miR-223. The p-AKT and IGF1R levels increased following miR-223 downregulation in mast cells. In addition, the specific PI3K‑inhibitor LY294002 decreased IL-6 secretion. Incubation with IGF1 resulted in the induction of IL-6 secretion in miR-223‑expressing mast cells. In conclusion, it was shown that miR-223 reduces IL-6 secretion in mast cells by inhibiting the IGF1R/PI3K signaling pathway.