Egr-1 is a key regulator of IL-17A-induced psoriasin upregulation in psoriasis.
Exp Dermatol 2015;
23:890-5. [PMID:
25256120 DOI:
10.1111/exd.12554]
[Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/21/2014] [Indexed: 12/11/2022]
Abstract
The early growth response (Egr)-1 is a transcriptional factor which plays an important role in the regulation of cell growth, differentiation, cell survival and immune responses. Emerging evidences including our data demonstrate that the Egr-1 expression is up-regulated in the psoriatic skin lesions. The purpose of this study was to investigate the significance and regulatory mechanism of Egr-1 in the pathogenesis of psoriasis. Through microarray analysis, we found out that psoriasin (S100A7) expression was increased in the Egr-1 overexpressed cells. Our results showed that IL-17A increased Egr-1 expression in the skin of psoriatic patients and cultured human keratinocytes. We then investigated activation of mitogen-activated protein kinase as an upstream signal regulator of Egr-1 expression. IL-17A-induced Egr-1 expression was suppressed by ERK inhibitor. In addition, IL-17A induced psoriasin expression in cultured keratinocytes and the skin of IL-17A intradermally injected mouse. IL-17A-mediated psoriasin upregulation was reduced after treatment of small interfering RNAs against Egr-1. Furthermore, the results of chromatin immunoprecipitation assays demonstrated that Egr-1 directly binds the psoriasin promoter. Our findings present a novel signalling mechanism by which IL-17A can induce the Egr-1-dependent psoriasin expression via the ERK pathway in human keratinocytes. This study suggests that Egr-1 may be a novel and important modulator in IL-17A-mediated immune response in psoriasis.
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