BY IL-1 SIGNALING, MONOCYTE-DERIVED CELLS DRAMATICALLY ENHANCE THE EPIDERMAL ANTIMICROBIAL RESPONSE TO LIPOPOLYSACCHARIDE.

Epithelia react to microbial pathogens by mounting a defensive response that includes the production of antimicrobial peptides. In this study, we show that, in human epidermal cultures, Escherichia coli LPS was a very weak direct inducer of human β-defensin (HBD)-2 mRNA and peptide, but the induction was greatly amplified when monocyte-derived cells (MoDeC) acted as intermediaries between LPS and the epidermis. IL-1R antagonist largely reversed the effect of MoDeC on epidermal HBD-2, indicating that, from among the many products of MoDeC, IL-1 was the dominant inducer of HBD-2 syntheses. In normal fresh human skin, which contains Langerhans cells and other myeloid cell types, in addition to keratinocytes, LPS also induced HBD-2 in an IL-1-dependent manner. In DNA microarray expression studies, HBD-2 was one of the most abundant mRNAs induced in epidermis by LPS-treated MoDeC, and its induction was reversed by IL-1Ra. Thus, epidermal response to LPS is potently amplified by MoDeC through IL-1-mediated signalling, leading to a selective increase in the synthesis of the antimicrobial peptide HBD-2. This pattern of responses establishes a key role for both IL-1 and HBD-2 in the host defense reaction of the epidermis.

Anti-microbial, Anti-microbial activity, Anti-microbial peptide, Anti-microbial peptides, Antimicrobial, Antimicrobial activity, Antimicrobial peptide, Antimicrobial peptides, DNA microarray, DNA microarray expression studies, EPI-200-3S, EpiDerm, Eschenichia LPS, Eschenichia coli, Gene expression, HBD-2, Host defense, Human beta-defensin-2 (HBD-2), IL-1, IL-1 signaling, IL-1r, IL-1ra, Lipopolysaccharide, Microarray, Microbial pathogens, Monocyte-derived cells (MoDeC), Pathogens

Lipopolysaccharide