Novel miR-290 regulates melanogenesis in Liancheng white ducks via the PI3K/AKT signaling pathway

This study aimed to investigate the role of a novel duck miR-290, which targets Phosphatidyqinositol-3 kinase (PI3K), in regulating melanogenesis in Liancheng white ducks. Differentially expressed miRNAs (DEmiRNA) associated with melanogenesis were first screened by transcriptome sequencing of mouth skin and skin from 130-day-old Liancheng white ducks. The interaction between novel miR-290 and the PI3K 3'UTR was verified by a dual-luciferase reporter assay. Primary duck melanocytes were then isolated from the mouth skin tissue, and the function of miR-290 was examined at the cellular level. The results revealed that novel miR-290 directly targeted PI3K, and the levels of p-PI3K and p-AKT were significantly decreased in the mouth skin compared with skin (P < 0.05), whereas p-GSK3β, Integrin-linked kinase (ILK), Microphthalmia-associated transcription factor (MITF), tyrosinase (TYR), and Melanocortin 1 Receptor (MC1R) were significantly increased in the mouth skin(P < 0.05). The isolated melanocytes were spindle-shaped and positive for DOPA and melanocytic markers.Overexpression of miR-290 significantly promoted melanocyte proliferation and melanin production (P < 0.01);(RT-qPCR) and Western blot analysis revealed that miR-290 inhibited the expression of PI3K and protein kinase B (AKT) (P < 0.05) and increased the expression of ILK, Glycogen Synthase Kinase 3β (GSK3β), MC1R, MITF, TYR, tyrosinase-related protein 1 (TYRP1), and tyrosinase-related protein 2 (TYRP2) (P < 0.05). In conclusion, this study identifies a novel duck miR-290 as a positive regulator of melanogenesis, which promotes melanocyte proliferation and melanin synthesis in Liancheng white ducks by suppressing PI3K/AKT signaling and activating downstream melanogenic genes.