title: Human colonic mucus is a reservoir for antimicrobial peptides.
abstract: OBJECTIVE
  To prevent bacterial adherence and translocation, the colonic mucosa is covered by a protecting mucus layer and the epithelium synthesizes antimicrobial peptides. The present qualitative study investigated the contents and interaction of these peptides in and with rectal mucus.
  
  
  METHODS
  Rectal mucus extracts were analyzed for antimicrobial activity and screened with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, Dot blot and immunohistochemistry for antimicrobial peptides. In addition, binding of AMPs to mucins was investigated by Western blot and enzyme-linked lectin assays.
  
  
  RESULTS
  In functional tests the mucus layer exhibited a strong antimicrobial activity. We detected 11 antimicrobial peptides in mucus extracts from healthy persons including the defensins HBD-1 and -3, the cathelicidin LL-37, ubiquitin, lysozyme, histones, high mobility group nucleosome-binding domain-containing protein 2, ubiquicidin and other ribosomal proteins. AMPs were bound by mucins but this was demonstrated to be reversible and inhibition of antibacterial activity was limited.
  
  
  CONCLUSIONS
  These findings indicate that epithelial antimicrobial peptides are retained in the intestinal mucus layer without losing their efficacy. Thus, the mucus layer and its composition provide an attractive drug target to restore antimicrobial barrier function in intestinal diseases.
authors.affiliation: Dr. Margarete Fischer-Bosch Institute of Clinical Pharmacology, University of Tübingen, Stuttgart, Germany.
authors.forename: Lena
authors.initials: L
authors.lastname: Antoni
authors.forename: Sabine
authors.initials: S
authors.lastname: Nuding
authors.forename: Dagmar
authors.initials: D
authors.lastname: Weller
authors.forename: Michael
authors.initials: M
authors.lastname: Gersemann
authors.forename: German
authors.initials: G
authors.lastname: Ott
authors.forename: Jan
authors.initials: J
authors.lastname: Wehkamp
authors.forename: Eduard F
authors.initials: EF
authors.lastname: Stange
mesh_terms: D000890:Anti-Infective Agents / Q000032:analysis*; D001441:Bacteroides fragilis / Q000254:growth & development; D002176:Candida albicans / Q000254:growth & development; D054804:Cathelicidins / Q000032:analysis / Q000378:metabolism; D023082:Defensins / Q000032:analysis / Q000378:metabolism; D013293:Enterococcus faecalis / Q000254:growth & development; D004926:Escherichia coli / Q000254:growth & development; D005434:Flow Cytometry; D024242:HMGN2 Protein / Q000032:analysis / Q000378:metabolism; D006657:Histones / Q000032:analysis / Q000378:metabolism; D006801:Humans; D007413:Intestinal Mucosa / Q000737:chemistry*; D008826:Microbial Sensitivity Tests; D009077:Mucins / Q000378:metabolism; D009093:Mucus / Q000737:chemistry* / Q000378:metabolism; D009113:Muramidase / Q000032:analysis / Q000378:metabolism; D010455:Peptides / Q000032:analysis* / Q000378:metabolism*; D012007:Rectum / Q000737:chemistry*; D012269:Ribosomal Proteins / Q000032:analysis / Q000378:metabolism; D013211:Staphylococcus aureus / Q000254:growth & development; D025801:Ubiquitin / Q000032:analysis / Q000378:metabolism
chemical_list: D000890:Anti-Infective Agents; D054804:Cathelicidins; D023082:Defensins; D024242:HMGN2 Protein; D006657:Histones; D009077:Mucins; D010455:Peptides; D012269:Ribosomal Proteins; D025801:Ubiquitin; C040469:ribosomal protein S30; D009113:Muramidase
keywords: AMP; Antimicrobial peptides;; ELLA; HMGN2; Inflammatory bowel disease;; Large intestine; MALDI-TOF-MS; Mucus;; RP-HPLC; antimicrobial peptide; enzyme-linked lectin assay; high mobility group nucleosome-binding domain-containing protein 2; matrix-assisted laser desorption/ionization time-of-flight mass spectrometry; reversed-phase high-performance liquid chromatography