title: Interactions among secretory immunoglobulin A, CD71, and transglutaminase-2 affect permeability of intestinal epithelial cells to gliadin peptides.
abstract: OBJECTIVE
  The transferrin receptor (CD71) is up-regulated in duodenal biopsy samples from patients with active celiac disease and promotes retrotransport of secretory immunoglobulin A (SIgA)-gliadin complexes. We studied intestinal epithelial cell lines that overexpress CD71 to determine how interactions between SIgA and CD71 promote transepithelial transport of gliadin peptides.
  
  
  METHODS
  We analyzed duodenal biopsy specimens from 8 adults and 1 child with active celiac disease. Caco-2 and HT29-19A epithelial cell lines were transfected with fluorescence-labeled small interfering RNAs against CD71. Interactions among IgA, CD71, and transglutaminase 2 (Tgase2) were analyzed by flow cytometry, immunoprecipitation, and confocal microscopy. Transcytosis of SIgA-CD71 complexes and intestinal permeability to the gliadin 3H-p31-49 peptide were analyzed in polarized monolayers of Caco-2 cells.
  
  
  RESULTS
  Using fluorescence resonance energy transfer and in situ proximity ligation assays, we observed physical interactions between SIgA and CD71 or CD71 and Tgase2 at the apical surface of enterocytes in biopsy samples and monolayers of Caco-2 cells. CD71 and Tgase2 were co-precipitated with SIgA, bound to the surface of Caco-2 cells. SIgA-CD71 complexes were internalized and localized in early endosomes and recycling compartments but not in lysosomes. In the presence of celiac IgA or SIgA against p31-49, transport of intact 3H-p31-49 increased significantly across Caco-2 monolayers; this transport was inhibited by soluble CD71 or Tgase2 inhibitors.
  
  
  CONCLUSIONS
  Upon binding to apical CD71, SIgA (with or without gliadin peptides) enters a recycling pathway and avoids lysosomal degradation; this process allows apical-basal transcytosis of bound peptides. This mechanism is facilitated by Tgase2 and might be involved in the pathogenesis of celiac disease.
authors: INSERM, UMR989, Paris, France; Université Paris Descartes-Sorbonne Paris Cité and Institut IMAGINE, Paris, France.
authors: Corinne
authors: C
authors: Lebreton
authors: INSERM, UMR989, Paris, France; Université Paris Descartes-Sorbonne Paris Cité and Institut IMAGINE, Paris, France.
authors: Sandrine
authors: S
authors: Ménard
authors: INSERM, UMR989, Paris, France; Université Paris Descartes-Sorbonne Paris Cité and Institut IMAGINE, Paris, France.
authors: Juliette
authors: J
authors: Abed
authors: INSERM, UMR699, Paris, France; Université Paris Diderot-Sorbonne Paris Cité, Paris, France.
authors: Ivan Cruz
authors: IC
authors: Moura
authors: Medical Nephrology Unit, S. Giovanni Hospital, University of Torino, Torino, Italy.
authors: Rosanna
authors: R
authors: Coppo
authors: Commissariat à Énergie Atomique, iBiTecS, Service d'Ingénierie Moléculaire des Protéines, Gif-sur-Yvette, France.
authors: Christophe
authors: C
authors: Dugave
authors: INSERM, UMR699, Paris, France; Université Paris Diderot-Sorbonne Paris Cité, Paris, France.
authors: Renato C
authors: RC
authors: Monteiro
authors: Université Paris Descartes-Sorbonne Paris Cité and Institut IMAGINE, Paris, France; CNRS, UMR8147, Hôpital Européen Georges Pompidou, Paris, France.
authors: Aurélie
authors: A
authors: Fricot
authors: Université Paris Descartes-Sorbonne Paris Cité and Institut IMAGINE, Paris, France; IFR 94, Imagery Platform, Hôpital Européen Georges Pompidou, Paris, France.
authors: Meriem Garfa
authors: MG
authors: Traore
authors: School of Life and Health. Aston University, Birmingham B4 7ET, United Kingdom.
authors: Martin
authors: M
authors: Griffin
authors: INSERM, UMR989, Paris, France; Université Paris Descartes-Sorbonne Paris Cité and Institut IMAGINE, Paris, France; APHP, Department of Gastroenterology, Hôpital Européen Georges Pompidou, Paris, France.
authors: Christophe
authors: C
authors: Cellier
authors: INSERM, UMR989, Paris, France; Université Paris Descartes-Sorbonne Paris Cité and Institut IMAGINE, Paris, France; APHP, Department of Gastroenterology, Hôpital Européen Georges Pompidou, Paris, France.
authors: Georgia
authors: G
authors: Malamut
authors: INSERM, UMR989, Paris, France; Université Paris Descartes-Sorbonne Paris Cité and Institut IMAGINE, Paris, France. Electronic address: nadine.cerf-bensussan@inserm.fr.
authors: Nadine
authors: N
authors: Cerf-Bensussan
authors: INSERM, UMR989, Paris, France; Université Paris Descartes-Sorbonne Paris Cité and Institut IMAGINE, Paris, France.
authors: Martine
authors: M
authors: Heyman
mesh_terms: D015703:Antigens, CD / Q000378:metabolism*; D001706:Biopsy; D018938:Caco-2 Cells; D002446:Celiac Disease / Q000378:metabolism* / Q000473:pathology; D016764:Cell Polarity; D004386:Duodenum / Q000378:metabolism* / Q000473:pathology; D005434:Flow Cytometry; D031541:Fluorescence Resonance Energy Transfer; D019204:GTP-Binding Proteins / Q000378:metabolism*; D005903:Gliadin / Q000378:metabolism*; D019073:HT29 Cells; D006801:Humans; D007071:Immunoglobulin A, Secretory / Q000378:metabolism*; D047468:Immunoprecipitation; D007408:Intestinal Absorption; D007413:Intestinal Mucosa / Q000378:metabolism* / Q000473:pathology; D008247:Lysosomes / Q000378:metabolism; D018613:Microscopy, Confocal; D010446:Peptide Fragments / Q000378:metabolism*; D010539:Permeability; D000091345:Protein Glutamine gamma Glutamyltransferase 2; D021381:Protein Transport; D034622:RNA Interference; D011990:Receptors, Transferrin / Q000378:metabolism*; D057900:Transcytosis; D014162:Transfection; D011503:Transglutaminases / Q000378:metabolism*
chemical_list: D015703:Antigens, CD; C068126:CD71 antigen; D007071:Immunoglobulin A, Secretory; D010446:Peptide Fragments; D011990:Receptors, Transferrin; D005903:Gliadin; D000091345:Protein Glutamine gamma Glutamyltransferase 2; D011503:Transglutaminases; D019204:GTP-Binding Proteins