miR-181a/b-5p negatively regulates keratinocytes proliferation by targeting MELK.

Accumulating evidence indicates that microRNAs (miRNAs) have a vital effect on the pathogenesis of psoriasis. This study is conducted to investigate the potential involvement of miR-181a-5p and miR-181b-5p in the proliferation of HaCaT keratinocytes. Cell viability and proliferation were evaluated respectively in this study using the CCK-8 and the 5-ethynyl-2'-deoxyuridine (EdU) assays. The expression of Maternal Embryonic Leucine Zipper Kinase (MELK) and Keratin 16 (KRT16) mRNA and protein in tissues and cells was assessed using quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting. The Luciferase reporter system analyzes the connection between miR-181a-5p/miR-181b-5p and MELK. The results showed that miR-181a/b-5p expression was downregulated in the psoriasis lesions and negatively regulated the proliferation of keratinocytes. MELK was directly targeted by miR-181a-5p/miR-181b-5p. In addition, HaCaT keratinocytes proliferation was inhibited by knockdown of MELK while promoted dramatically by MELK overexpression. Notably, miR-181a/b-5p mimics could attenuate the effects of MELK in keratinocytes. In conclusion, our research findings suggested miR-181a-5p and miR-181b-5p negatively regulate keratinocyte proliferation by targeting MELK, providing potential diagnostic biomarkers and therapeutic targets for psoriasis.