title: The role of RNase 7 in innate cutaneous defense against Pseudomonas aeruginosa.
abstract: The ribonuclease RNase 7 is a major skin-derived human antimicrobial protein expressed in keratinocytes. Here we show that the gram-negative pathogen Pseudomonas aeruginosa secretes factor(s) that induced RNase 7 gene and protein expression in human primary keratinocytes. The metalloprotease inhibitor marimastat, the epidermal growth factor receptor (EGFR) inhibitor AG1478 and the EGFR blocking antibody cetuximab significantly attenuated this induction, indicating an important role of the EGFR for the P. aeruginosa-mediated RNase 7 induction. In line with this, siRNA-mediated downregulation of ADAM17, a metalloprotease known to proteolytically mediate the release of soluble EGFR ligands, decreased the P. aeruginosa-mediated RNase 7 induction in keratinocytes. The impact of the EGFR was also demonstrated in a human 3D skin equivalent where blockade of the EGFR diminished induction of RNase 7 by P. aeruginosa. Blockade of Toll-like receptor 5 (TLR5), a pattern recognition receptor (PRR) known to be activated by P. aeruginosa, only moderately reduced the P. aeruginosa-mediated RNase 7 induction in keratinocytes. The functional relevance of RNase 7 to participate in cutaneous defense against P. aeruginosa was demonstrated by antibodies that neutralized the antimicrobial activity of RNase 7. These antibodies significantly inhibited the capacity of human stratum corneum skin extracts to control growth of P. aeruginosa. Taken together, our results indicate that P. aeruginosa induces the expression of RNase 7 in keratinocytes in an EGFR-dependent manner. Enhanced release of RNase 7 contributes to control cutaneous growth of P. aeruginosa.
authors: Department of Dermatology, University of Kiel, Kiel, Germany.
authors: Franziska
authors: F
authors: Rademacher
authors: Department of Dermatology, University of Kiel, Kiel, Germany.
authors: Maren
authors: M
authors: Simanski
authors: Department of Dermatology, University of Kiel, Kiel, Germany.
authors: Lena
authors: L
authors: Schröder
authors: Department of Dermatology, Medical University of Vienna, Vienna, Austria.
authors: Michael
authors: M
authors: Mildner
authors: Department of Dermatology, University of Kiel, Kiel, Germany.
authors: Jürgen
authors: J
authors: Harder
mesh_terms: D000072198:ADAM17 Protein / Q000235:genetics*; D057134:Antibodies, Neutralizing / Q000494:pharmacology; D002478:Cells, Cultured; D000068818:Cetuximab / Q000494:pharmacology; D004817:Epidermis / Q000187:drug effects / Q000276:immunology; D066246:ErbB Receptors / Q000187:drug effects / Q000378:metabolism*; D015870:Gene Expression / Q000187:drug effects*; D020868:Gene Silencing; D006801:Humans; D006877:Hydroxamic Acids / Q000494:pharmacology; D015603:Keratinocytes; D009940:Organoids; D011550:Pseudomonas aeruginosa / Q000378:metabolism*; D011799:Quinazolines / Q000494:pharmacology; D034741:RNA, Small Interfering / Q000494:pharmacology; D012260:Ribonucleases / Q000235:genetics* / Q000276:immunology / Q000378:metabolism*; D015398:Signal Transduction; D012867:Skin / Q000276:immunology / Q000378:metabolism*; D051198:Toll-Like Receptor 5 / Q000378:metabolism; D020032:Tyrphostins / Q000494:pharmacology
chemical_list: D057134:Antibodies, Neutralizing; D006877:Hydroxamic Acids; D011799:Quinazolines; D034741:RNA, Small Interfering; C495346:TLR5 protein, human; D051198:Toll-Like Receptor 5; D020032:Tyrphostins; C101044:RTKI cpd; C100342:marimastat; C512478:EGFR protein, human; D066246:ErbB Receptors; D012260:Ribonucleases; C470000:Ribonuclease 7; D000072198:ADAM17 Protein; C000606462:ADAM17 protein, human; D000068818:Cetuximab
keywords: antimicrobial peptides; cutaneous innate defense; epidermal growth factor receptor; keratinocytes