title: Gliadin-mediated proliferation and innate immune activation in celiac disease are due to alterations in vesicular trafficking.
abstract: OBJECTIVE
  Damage to intestinal mucosa in celiac disease (CD) is mediated both by inflammation due to adaptive and innate immune responses, with IL-15 as a major mediator of the innate immune response, and by proliferation of crypt enterocytes as an early alteration of CD mucosa causing crypts hyperplasia. We have previously shown that gliadin peptide P31-43 induces proliferation of cell lines and celiac enterocytes by delaying degradation of the active epidermal growth factor receptor (EGFR) due to delayed maturation of endocytic vesicles. IL-15 is increased in the intestine of patients affected by CD and has pleiotropic activity that ultimately results in immunoregulatory cross-talk between cells belonging to the innate and adaptive branches of the immune response. Aims of this study were to investigate the role of P31-43 in the induction of cellular proliferation and innate immune activation.
  
  
  RESULTS
  Cell proliferation was evaluated by bromodeoxyuridine (BrdU) incorporation both in CaCo-2 cells and in biopsies from active CD cases and controls. We used real-time PCR to evaluate IL-15 mRNA levels and FACS as well as ELISA and Western Blot (WB) analysis to measure protein levels and distribution in CaCo-2 cells. Gliadin and P31-43 induce a proliferation of both CaCo-2 cells and CD crypt enterocytes that is dependent on both EGFR and IL-15 activity. In CaCo-2 cells, P31-43 increased IL-15 levels on the cell surface by altering intracellular trafficking. The increased IL-15 protein was bound to IL15 receptor (IL-15R) alpha, did not require new protein synthesis and functioned as a growth factor.
  
  
  CONCLUSIONS
  In this study, we have shown that P31-43 induces both increase of the trans-presented IL-15/IL5R alpha complex on cell surfaces by altering the trafficking of the vesicular compartments as well as proliferation of crypt enterocytes with consequent remodelling of CD mucosa due to a cooperation of IL-15 and EGFR.
authors.affiliation: Department of Pediatrics, European Laboratory for the Investigation of Food-Induced Diseases, University of Naples Federico II, Naples, Italy. mv.barone@unina.it
authors.forename: M Vittoria
authors.initials: MV
authors.lastname: Barone
authors.forename: Delia
authors.initials: D
authors.lastname: Zanzi
authors.forename: Mariantonia
authors.initials: M
authors.lastname: Maglio
authors.forename: Merlin
authors.initials: M
authors.lastname: Nanayakkara
authors.forename: Sara
authors.initials: S
authors.lastname: Santagata
authors.forename: Giuliana
authors.initials: G
authors.lastname: Lania
authors.forename: Erasmo
authors.initials: E
authors.lastname: Miele
authors.forename: Maria Teresa Silvia
authors.initials: MT
authors.lastname: Ribecco
authors.forename: Francesco
authors.initials: F
authors.lastname: Maurano
authors.forename: Renata
authors.initials: R
authors.lastname: Auricchio
authors.forename: Carmen
authors.initials: C
authors.lastname: Gianfrani
authors.forename: Silvano
authors.initials: S
authors.lastname: Ferrini
authors.forename: Riccardo
authors.initials: R
authors.lastname: Troncone
authors.forename: Salvatore
authors.initials: S
authors.lastname: Auricchio
mesh_terms: D001706:Biopsy; D018938:Caco-2 Cells; D002446:Celiac Disease / Q000276:immunology / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology; D049109:Cell Proliferation / Q000187:drug effects*; D002478:Cells, Cultured; D020895:Enterocytes / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D066246:ErbB Receptors / Q000378:metabolism / Q000502:physiology; D005786:Gene Expression Regulation / Q000187:drug effects; D005903:Gliadin / Q000494:pharmacology*; D006801:Humans; D007113:Immunity, Innate / Q000187:drug effects*; D019409:Interleukin-15 / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D007413:Intestinal Mucosa / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D021381:Protein Transport / Q000187:drug effects; D022161:Transport Vesicles / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism
chemical_list: D019409:Interleukin-15; D005903:Gliadin; C512478:EGFR protein, human; D066246:ErbB Receptors