Wilms' tumor 1-associating protein contributes to psoriasis by promoting keratinocytes proliferation via regulating cyclinA2 and CDK2

Wilms’ tumor 1-associating protein (WTAP) is a ubiquitously expressed nuclear protein, and involved in multiple pathophysiological processes, including cell cycle, RNA splicing and stabilization, N6-methyladenosine RNA modification, cell proliferation, and apoptosis as well as embryonic development. Here, we investigated the specific role of WTAP in the pathogenesis of psoriasis and its underlying mechanism. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR), western blot analyses and multi-spectrum immunohistochemistry were applied to evaluate the level of WTAP expression in psoriatic skin and normal skin. HaCaT cells was stably transfected with WTAP small interfering (si)RNA and plasmid using Lipofectamine®2000 and proliferation was determined by CCK8. Apoptosis and cell cycle analysis were conducted by flow cytometry. Western blot assay was used to explore the expression levels of cell cycle-related proteins in HaCaT cells after WTAP overexpression or inhibition. Furthermore, HaCaT cells were stimulated with proinflammatory cytokines (ie, IL-17A, IL-22, IL-1a, oncostatin M, and TNF-a) to assess WTAP expression. We demonstrated that the mRNA and protein levels of WTAP were significantly increased in lesional skins of psoriasis patients and psoriatic cell model compared with normal controls. WTAP was highly expressed in epidermis rather than dermis. Overexpression of WTAP promoted keratinocytes proliferation, which might be related to the up-regulation of cyclinA2 and CDK2. These results indicate that overexpression of WTAP may contribute to the pathogenesis of psoriasis by regulating cell cycle progression and highlight WTAP as a potential therapeutic target for psoriasis treatment.