title: NF-kappaB- and AP-1-mediated induction of human beta defensin-2 in intestinal epithelial cells by Escherichia coli Nissle 1917: a novel effect of a probiotic bacterium.
abstract: Little is known about the defensive mechanisms induced in epithelial cells by pathogenic versus probiotic bacteria. The aim of our study was to compare probiotic bacterial strains such as Escherichia coli Nissle 1917 with nonprobiotic, pathogenic and nonpathogenic bacteria with respect to innate defense mechanisms in the intestinal mucosal cell. Here we report that E. coli strain Nissle 1917 and a variety of other probiotic bacteria, including lactobacilli--in contrast to more than 40 different E. coli strains tested--strongly induce the expression of the antimicrobial peptide human beta-defensin-2 (hBD-2) in Caco-2 intestinal epithelial cells in a time- and dose-dependent manner. Induction of hBD-2 through E. coli Nissle 1917 was further confirmed by activation of the hBD-2 promoter and detection of the hBD-2 peptide in the culture supernatants of E. coli Nissle 1917-treated Caco-2 cells. Luciferase gene reporter analyses and site-directed mutagenesis experiments demonstrated that functional binding sites for NF-kappaB and AP-1 in the hBD-2 promoter are required for induction of hBD-2 through E. coli Nissle 1917. Treatment with the NF-kappaB inhibitor Helenalin, as well as with SP600125, a selective inhibitor of c-Jun N-terminal kinase, blocked hBD-2 induction by E. coli Nissle 1917 in Caco-2 cells. SB 202190, a specific p38 mitogen-activated protein kinase inhibitor, and PD 98059, a selective inhibitor of extracellular signal-regulated kinase 1/2, were ineffective. This report demonstrates that probiotic bacteria may stimulate the intestinal innate defense through the upregulation of inducible antimicrobial peptides such as hBD-2. The induction of hBD-2 may contribute to an enhanced mucosal barrier to the luminal bacteria.
authors.affiliation: Department of Internal Medicine I, Robert Bosch Hospital, Stuttgart, Germany. jwehkamp@ucdavis.edu
authors.forename: Jan
authors.initials: J
authors.lastname: Wehkamp
authors.forename: Jürgen
authors.initials: J
authors.lastname: Harder
authors.forename: Kai
authors.initials: K
authors.lastname: Wehkamp
authors.forename: Birte
authors.initials: B
authors.lastname: Wehkamp-von Meissner
authors.forename: Miriam
authors.initials: M
authors.lastname: Schlee
authors.forename: Corinne
authors.initials: C
authors.lastname: Enders
authors.forename: Ulrich
authors.initials: U
authors.lastname: Sonnenborn
authors.forename: Sabine
authors.initials: S
authors.lastname: Nuding
authors.forename: Stig
authors.initials: S
authors.lastname: Bengmark
authors.forename: Klaus
authors.initials: K
authors.lastname: Fellermann
authors.forename: Jens Michael
authors.initials: JM
authors.lastname: Schröder
authors.forename: Eduard F
authors.initials: EF
authors.lastname: Stange
mesh_terms: D001665:Binding Sites; D018938:Caco-2 Cells; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism* / Q000382:microbiology*; D004926:Escherichia coli / Q000145:classification / Q000502:physiology*; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D007422:Intestines / Q000166:cytology* / Q000382:microbiology; D048031:JNK Mitogen-Activated Protein Kinases; D008070:Lipopolysaccharides / Q000494:pharmacology; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000235:genetics; D020218:Response Elements / Q000235:genetics; D015398:Signal Transduction / Q000187:drug effects; D018808:Transcription Factor AP-1 / Q000378:metabolism*; D023083:beta-Defensins / Q000235:genetics*; D048051:p38 Mitogen-Activated Protein Kinases
chemical_list: C106641:DEFB4A protein, human; D008070:Lipopolysaccharides; D016328:NF-kappa B; D018808:Transcription Factor AP-1; D023083:beta-Defensins; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases