Enhanced Dectin-1 Induced By IL-17A And TNF-α Can Promote The Proliferation Of Keratinocytes In Psoriasis

Objective:Pro-inflammatory cytokines including IL-17 A and TNF-α have been identified to play a significant role in the pathophysiology of psoriasis,and biologic agents targeting IL-17 A and TNF-α have demonstrated remarkable clinical outcomes.While the underlying mechanism of how IL-17 A and TNF-α specifically regulate keratinocyte proliferation has not been fully elucidated.This study aims to explore the unexplained molecular mechanism of IL-17 A and TNF-α and provide a theoretical basis for improving the related pathological mechanism.Methods:(1)Bioinformatics was used to analyze the psoriasis sequencing results in the GEO database,and the important differential gene CLEC7A(Dectin-1),which appeared significantly upregulated in psoriasis lesions,was screened by Limma differential analysis,GO analysis,KEGG pathway analysis and WGCNA analysis.(2)The expression of Dectin-1 was detected by q RT-PCR and immunofluorescence techniques in psoriasis vulgaris lesions and normal skin tissues,and the cell types with high expression of Dectin-1 were identified.The mouse psoriasis-like dermatitis model and the control model were constructed by topical application of imiquimod and vaseline ointment on the dorsal skin of mice,and the modified PASI score and H&E staining were used to evaluate the phenotype and histopathological change of each group.And then the differences in Dectin-1 expression in the skin tissues of the two groups of mice were detected by Western blot,q RT-PCR and immunofluorescence,and the cell types with high Dectin-1 expression were determined.(3)The correlation between IL-17 A,TNF-α and Dectin-1 gene expression within psoriatic lesions in the GEO database was analyzed.And the effects of IL-17 A and TNF-α on Dectin-1 expression in Ha Ca T cells were verified by in vitro cytological assays.(4)The effects of IL-17 A and TNF-α on the proliferation and apoptosis of Ha Ca T cells were detected by cell counting,CCK-8 and flow cytometry.Changes in apoptosis of Ha Ca T cells were detected by in vitro cytological assay after silencing Dectin-1 expression in Ha Ca T cells using si RNA.And then IL-17 A and TNF-α were added to Ha Ca T cells after Dectin-1 silencing,and the changes of Ha Ca T cell proliferation were detected to investigate whether silencing Dectin-1 expression could affect IL-17 A and TNF-α-induced cell proliferation.The changes in signaling pathway molecules affecting cell proliferation after Dectin-1 quiescence were then examined by Western blot.(5)The effects of Dectin-1 agonist curdlan on proliferation and apoptosis of Ha Ca T cells were detected by cell counting,CCK-8 and flow cytometry.Changes in signaling pathway molecules involved in the proliferation of Ha Ca T cells affected by curdlan were detected by Western blot.Results:(1)Analysis of the combined psoriasis-related dataset GSE13355,GSE14905 and GSE78097 showed that the m RNA level of Dectin-1 was upregulated at in psoriatic lesions and closely associated with the psoriasis clinical traits.(2)Dectin-1 expression was upregulated in psoriatic skin lesions compared with normal skin tissues,and was highly expressed in keratinocytes.Compared with the vaseline group,Dectin-1 was up-regulated in the imiquimod group and highly expressed in keratinocytes.(3)The expression of IL-17 A,TNF-α and Dectin-1 within psoriatic lesions was positively correlated.And IL-17 A and TNF-α could upregulate the expression of Dectin-1 in Ha Ca T.IL-17 A could promote the proliferation of Ha Ca T cells,but had no significant effect on apoptosis,while TNF-αdid not significantly promote cell proliferation due to induction of apoptosis in Ha Ca T cells.(4)Silencing Dectin-1 had no obvious effect on the apoptosis of Ha Ca T cells,but could significantly inhibit the cell proliferation induced by IL-17 A and TNF-α by down-regulating the Syk/NF-κB signaling pathway.(5)Activation of Dectin-1 promoted the proliferation of Ha Ca T cells through activating the Syk/NF-κB signaling pathway.Conclusion:Dectin-1 is one of the important functional genes associated with the psoriasis,which is highly expressed in keratinocytes within psoriatic lesions.The levels of IL-17 A and TNF-α in psoriatic lesions were positively correlated with the expression of Dectin-1.IL-17 A and TNF-α could promote the proliferation of Ha Ca T by upregulating Dectin-1expression and thereby activating the Syk/NF-κB signaling pathway,which lead to the abnormal epidermal proliferation in psoriatic lesions...