Shikonin Inhibits Inflammation of Psoriasis Cell Model by Regulating cGAS/STING Signaling Pathway

Abstract:

Objective To investigate the effect of shikosin （SHI） on psoriasis （PSO） and explore the underlying mechanism via the cyclic guanosine monophosphate-adenosine monophosphate synthase （cGAS）/stimulator of interferon genes （STING） signaling pathway.Method HaCaT cells were classified into normal culture（Control）， a mixture of five proinflammatory cytokines（M5）， low-， medium-， and high-dose SHI （L-SHI， M-SHI， and H-SHI， respectively）， and SHI+ADU-S100 groups. The cells in the M5 group were stimulated with 10 μg·L^-1 interleukin （IL）-1α， IL-17， IL-22， tumor necrosis factor （TNF）-α， and oncostatin M （OSM） for 48 h. The cells in the L-SHI， M-SHI， and H-SHI groups were treated with 0.1， 1， 10 μmol·L^-1 SHI， respectively， on the basis of the treatment in the M5 group. The cells in the SHI+ADU-S100 group were treated with 10 μmol·L^-1 STING activator ADU-S100 on the basis of the treatment in the H-SHI group. The methyl thiazolyl tetrazolium （MTT） assay and colony formation assay were employed to examine the effect of SHI on the proliferation of HaCaT cells. The wound healing assay was employed to examine the effect of SHI on the migration of HaCaT cells. Flow cytometry was employed to detect the effect of SHI on the apoptosis of HaCaT cells. Enzyme-linked immunosorbent assay was employed to measure the levels of IL-1β， IL-6， IL-15， IL-23， and interferon-γ （IFN-γ） in HaCaT cells. Western blot was employed to determine the protein levels of cGAS and STING in HaCaT cells.Result Compared with Control group， the M5 group showed decreased survival rate， colony formation， and would healing rate of HaCaT cells， increased apoptosis rate， elevated levels of IL-1β， IL-6， IL-15， IL-23， and IFN-γ， and up-regulated protein levels of cGAS and STING （P<0.01）. Compared with the M5 group， the L-SHI， M-SHI， and H-SHI groups showed increased survival rate， cell colony formation， and wound healing rate， decreased apoptosis rate， lowered levels of IL-1β， IL-6， IL-15， IL-23， and IFN-γ， and down-regulated protein levels of cGAS and STING （P<0.01）. Compared with the H-SHI group， the SHI+ADU-S100 group showed decreased survival rate， cell colony formation， and wound healing rate， increased apoptosis rate， risen levels of IL-1β， IL-6， IL-15， IL-23， and IFN-γ， and up-regulated protein levels of cGAS and STING （P<0.01）.Conclusion SHI can inhibit the inflammation in the cell model of PSO by inhibiting the cGAS/STING signaling pathway.