title: Gliadin Induces Neutrophil Migration via Engagement of the Formyl Peptide Receptor, FPR1.
abstract: BACKGROUND
  Gliadin, the immunogenic component within gluten and trigger of celiac disease, is known to induce the production of Interleukin-8, a potent neutrophil-activating and chemoattractant chemokine. We sought to study the involvement of neutrophils in the early immunological changes following gliadin exposure.
  
  
  METHODS
  Utilizing immunofluorescence microscopy and flow cytometry, the redistribution of major tight junction protein, Zonula occludens (ZO)-1, and neutrophil recruitment were assessed in duodenal tissues of gliadin-gavaged C57BL/6 wild-type and Lys-GFP reporter mice, respectively. Intravital microscopy with Lys-GFP mice allowed monitoring of neutrophil recruitment in response to luminal gliadin exposure in real time. In vitro chemotaxis assays were used to study murine and human neutrophil chemotaxis to gliadin, synthetic alpha-gliadin peptides and the neutrophil chemoattractant, fMet-Leu-Phe, in the presence or absence of a specific inhibitor of the fMet-Leu-Phe receptor-1 (FPR1), cyclosporine H. An irrelevant protein, zein, served as a control.
  
  
  RESULTS
  Redistribution of ZO-1 and an influx of CD11b+Lys6G+ cells in the lamina propria of the small intestine were observed upon oral gavage of gliadin. In vivo intravital microscopy revealed a slowing down of GFP+ cells within the vessels and influx in the mucosal tissue within 2 hours after challenge. In vitro chemotaxis assays showed that gliadin strongly induced neutrophil migration, similar to fMet-Leu-Phe. We identified thirteen synthetic gliadin peptide motifs that induced cell migration. Blocking of FPR1 completely abrogated the fMet-Leu-Phe-, gliadin- and synthetic peptide-induced migration.
  
  
  CONCLUSIONS
  Gliadin possesses neutrophil chemoattractant properties similar to the classical neutrophil chemoattractant, fMet-Leu-Phe, and likewise uses FPR1 in the process.
authors.affiliation: Department of Pediatrics, Mucosal Immunology and Biology Research Center, Massachusetts General Hospital East, Charlestown, Massachusetts, United States of America.
authors.forename: Karen M
authors.initials: KM
authors.lastname: Lammers
authors.affiliation: Lymphocyte Biology Section, Laboratory of Immunology, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, Maryland, United States of America.
authors.forename: Marcello
authors.initials: M
authors.lastname: Chieppa
authors.affiliation: Laboratory of Cellular and Molecular Biology, Center for Cancer Research, NCI, NIH, Bethesda, Maryland, United States of America.
authors.forename: Lunhua
authors.initials: L
authors.lastname: Liu
authors.affiliation: Department of Gastroenterology, Massachusetts General Hospital, Boston, Massachusetts, United States of America.
authors.forename: Song
authors.initials: S
authors.lastname: Liu
authors.affiliation: Department of Gastroenterology, Massachusetts General Hospital, Boston, Massachusetts, United States of America.
authors.forename: Tatsushi
authors.initials: T
authors.lastname: Omatsu
authors.affiliation: Laboratory of Cellular and Molecular Biology, Center for Cancer Research, NCI, NIH, Bethesda, Maryland, United States of America.
authors.forename: Mirkka
authors.initials: M
authors.lastname: Janka-Junttila
authors.affiliation: Department of Pediatrics, Mucosal Immunology and Biology Research Center, Massachusetts General Hospital East, Charlestown, Massachusetts, United States of America.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Casolaro
authors.affiliation: Department of Gastroenterology, Massachusetts General Hospital, Boston, Massachusetts, United States of America.
authors.forename: Hans-Christian
authors.initials: HC
authors.lastname: Reinecker
authors.affiliation: Laboratory of Cellular and Molecular Biology, Center for Cancer Research, NCI, NIH, Bethesda, Maryland, United States of America.
authors.forename: Carole A
authors.initials: CA
authors.lastname: Parent
authors.affiliation: Department of Pediatrics, Mucosal Immunology and Biology Research Center, Massachusetts General Hospital East, Charlestown, Massachusetts, United States of America.
authors.forename: Alessio
authors.initials: A
authors.lastname: Fasano
mesh_terms: D000818:Animals; D039481:CD11b Antigen / Q000378:metabolism; D002446:Celiac Disease / Q000378:metabolism; D002465:Cell Movement / Q000187:drug effects*; D002630:Chemotactic Factors / Q000378:metabolism; D002634:Chemotaxis, Leukocyte / Q000187:drug effects; D004386:Duodenum / Q000187:drug effects / Q000378:metabolism; D005903:Gliadin / Q000009:adverse effects*; D006801:Humans; D007421:Intestine, Small / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000378:metabolism; D020556:Neutrophil Infiltration / Q000187:drug effects; D009504:Neutrophils / Q000187:drug effects*; D010446:Peptide Fragments / Q000378:metabolism; D044042:Receptors, Formyl Peptide / Q000378:metabolism*; D019108:Tight Junctions / Q000187:drug effects / Q000378:metabolism; D062826:Zonula Occludens-1 Protein / Q000378:metabolism
chemical_list: D039481:CD11b Antigen; D002630:Chemotactic Factors; C469988:Fpr1 protein, mouse; D010446:Peptide Fragments; D044042:Receptors, Formyl Peptide; C569043:Tjp1 protein, mouse; D062826:Zonula Occludens-1 Protein; D009240:N-Formylmethionine Leucyl-Phenylalanine; D005903:Gliadin