Triptolide Inhibits the Proliferation of HaCaT Cells Induced by IL22 via Upregulating miR-181b-5p

Abstract

Background

Evidence has been shown that triptolide was effective in the treatment of psoriasis; however, the mechanisms remain poorly understood. Thus, this study aimed to investigate the role of triptolide on the proliferation and differentiation of HaCaT cells which are treated with IL22 to mimic abnormal proliferation/differentiation in keratinocyte of psoriasis.

Materials and Methods

HaCaT cells were transfected with miR-181b-5p antagomir for 24 h, and then exposed to 10 μM Triptolide for 24 h, following by 100 ng/mL of IL22 for 24 h. In addition, the proliferation and cell cycle distribution in HaCaT cells were assessed by immunofluorescence or flow cytometry assays, respectively.

Results

Triptolide obviously upregulated the level of miR-181b-5p in HaCaT cells. In addition, triptolide significantly inhibited IL22-induced proliferation of HaCaT cells via inducing cell cycle arrest. Moreover, IL22 markedly inhibited the differentiation of HaCaT cells, and this phenomenon was reversed by triptolide treatment. In contrast, the effects of triptolide on the proliferation and differentiation in IL22-stimulated HaCaT cells were notably reversed by miR-181b-5p antagomir. Moreover, dual-luciferase assay showed that E2F5 was the direct target of miR-181b-5p in HaCaT cells. Meanwhile, upregulation of miR-181b-5p obviously decreased the level of E2F5 in HaCaT cells.

Conclusion

In this study, we found that triptolide could inhibit the proliferation and promote the differentiation in IL22-stimulated keratinocytes via upregulating miR-181b-5p. These data indicated that triptolide may be a potential agent for the treatment of psoriasis.

Keywords:

• psoriasis
• triptolide
• keratinocytes
• miR-181b
• differentiation

Abbreviations

TwHF, Tripterygium wilfordii Hook F; 3ʹ-UTRs, 3ʹ-untranslated regions; HEK, human epidermal keratinocytes; CCK-8, Cell Counting Kit-8; CDK2, cyclin-dependent kinase 2; RT-qPCR, reverse transcription-quantitative polymerase chain reaction; NC, negative control; EdU, 5-ethynyl-2ʹ-deoxyuridine; WT, wild-type; MT, mutant.

Disclosure

Qi He and Bo Zhang should be considered as co-first authors. The authors declare no competing financial interests.