IL-33 impacts on the skin barrier by downregulating the expression of filaggrin

Abstract

IL-33 is a member of the IL-1 family of cytokines that is constitutively expressed in healthy skin and was found to be increased in the skin of patients with atopic dermatitis (AD). Because it can be released after tissue damage or physical stress including scratching of the skin,1 it has been classified as an alarmin concerned with alerting the immune system.2 It enhances TH2 responses by inducing IL-5 and IL-13 as well as TH1 responses via upregulation of IFN-γ. Keratinocytes are known producer cells of IL-33 and also express the receptor complex consisting of ST2 and IL-1RAcP on their surface. The aim of this study was to investigate the effect of IL-33 on keratinocytes, skin biopsies, and living skin equivalents with regard to the regulation of the skin barrier molecule filaggrin (FLG).