MiR-149-5p inhibits cell proliferation, promotes cell apoptosis and retards cell cycle of IL-22-stimulated HaCaT and NHEK keratinocytes via regulating PDE4D

Psoriasis is a chronic autoimmune skin disease with unclear pathogenesis. It was found that miR-149-5p was significantly decreased in psoriatic lesion tissues. In this study, we aims to investigate the role and related molecular mechanism of miR-149-5p on psoriasis.IL-22 was used to stimulate HaCaT and NHEK cells to establish psoriasis model in vitro. The miR-149-5p and phosphodiesterase 4D (PDE4D) expression levels were detected by quantitative real-time PCR. HaCaT and NHEK cells proliferation was determined by Cell Couting Kit-8 assay. The cell apoptosis and cell cycle were detected by flow cytometry. The cleaved Caspase-3, Bax and Bcl-2 protein expressions were detected by western blot. The targeting relationship between PDE4D and miR-149-5p was predicted and confirmed by Starbase V2.0 and dual-luciferase reporter assay, respectively.There was a low expression level of miR-149-5p and a high expression of PDE4D in psoriatic lesion tissues. MiR-149-5p could target PDE4D. IL-22 promoted HaCaT and NHEK cells proliferation, while inhibited cell apoptosis and accelerated cell cycle. Moreover, IL-22 decreased the expressions of cleaved Caspase-3 and Bax, and increased the expression of Bcl-2. And the overexpressed miR-149-5p promoted HaCaT and NHEK cells apoptosis, inhibited cell proliferation and retarded cell cycle, meanwhile increased the cleaved Caspase-3 and Bax expressions, decreased the Bcl-2 expression. In addition, PDE4D overexpression has the opposite effect as miR-149-5p.The overexpressed miR-149-5p inhibits IL-22-stimulated HaCaT and NHEK keratinocytes proliferation, promotes cell apoptosis and retards cell cycle by down-regulating the expression of PDE4D, which could be the promising therapeutic target of psoriasis.