Flagellin is the principal inducer of the antimicrobial peptide S100A7c (psoriasin) in human epidermal keratinocytes exposed to Escherichia coli
Arby Abtina b, Leopold Eckharta b, Michael Mildnera b, Флориан Груберa b, Jens‐Michael Schröderc d, Erwin Tschachlera b e f
- aDepartment of Dermatology Medical University of Vienna Vienna Austria
- bDepartment of DermatologyMedical University of ViennaViennaAustria
- cDepartment of Dermatology University Hospital Schleswig-Holstein University of Kiel Kiel Germany
- dDepartment of Dermatology University Hospital Schleswig-HolsteinUniversity of KielKielGermany
- eCentre de Recherches et d'investigations Epidermiques et Sensorielles Neuilly sur Seine France
- fCentre de Recherches et d'investigations Epidermiques et SensoriellesNeuilly sur SeineFrance
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Abstract
ABSTRACT Epidermal keratinocytes (KCs) express antimicrobial peptides as a part of the innate immune response. It has recently been shown that the culture supernatant of Escherichia coli induces the expression of S100A7c (psoriasin) in KCs and that S100A7c efficiently kills E. coli. Here we have investigated which of the microbial components triggers the up‐regulation of S100A7c expression. Exposure of human primary KCs to ligands of the human Toll‐like receptors (TLRs) revealed that only the TLR5 ligand flagellin strongly induced the expression of S100A7c mRNA and protein, whereas all other TLR ligands had no significant effect. In contrast to the supernatant from flagellated wild‐type (WT) E. coli , the supernatant of a flagellin‐deficient E. coli strain (ΔFliC) did not induce S100A7c expression. Small interfering RNA‐mediated knockdown of TLR5 expression suppressed the ability of KCs to up‐regulate S100A7c expression in response to both flagellin and WT E. coli supernatant. Taken together, our data demonstrate that bacterial flagellin is essential and sufficient for the induction of S100A7c expression in KCs by E. coli. —Abtin, A., Eckhart, L., Mildner, M., Gruber, F., Schröder, J‐M., Tschachler, E. Flagellin is the principal inducer of the antimicrobial peptide S100A7c (psoriasin) in human epidermal keratinocytes exposed to Escherichia coli. FASEB J. 22, 2168–2176 (2008)
TL;DRIt is demonstrated that bacterial flagellin is essential and sufficient for the induction of S100A7c expression in KCs by E. coli and small interfering RNA‐mediated knockdown of TLR5 expression suppressed the ability of KCs to up‐regulate S 100A7C expression in response to both flageLLin and WT E. bacteria. (Semantic Scholar)