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Flagellin is the principal inducer of the antimicrobial peptide S100A7c (psoriasin) in human epidermal keratinocytes exposed to Escherichia coli
Author(s) -
Abtin Arby,
Eckhart Leopold,
Mildner Michael,
Gruber Florian,
Schröder Jens-Michael,
Tschachler Erwin
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fj.07-104117
Subject(s) - flagellin , tlr5 , escherichia coli , gene knockdown , innate immune system , microbiology and biotechnology , biology , chemistry , receptor , toll like receptor , gene , biochemistry
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)