title: Intestinal epithelial cells express galectin-9 in patients with food allergy that plays a critical role in sustaining allergic status in mouse intestine.
abstract: OBJECTIVE
  Mechanisms in sustaining the allergic hypersensitivity status in the body are unclear. Galectin-9 (Gal-9) has strong immune regulatory capacity. The present study aims to elucidate the role of Gal-9 in sustaining allergic status in the intestine.
  
  
  METHODS
  Duodenal biopsies were obtained from 20 patients with peptic ulcer and food allergy (FA). The expression of Gal-9 in intestinal tissue was examined at both protein level and mRNA level. Two coculture systems with intestinal epithelial cells (IEC) and mast cells, or dendritic cells (DC) and T cells were established to investigate the source of Gal-9 in the intestine and the mechanism by which Gal-9 modulated DC's phenotyping and sustained the T helper 2 polarization.
  
  
  RESULTS
  Normal IEC showed mild expression of Gal-9 that was markedly enhanced in patients with FA. Mast cells had the capability to induce IEC to produce Gal-9 via releasing tryptase that activated the proteinase-activated receptor 2 on IEC. Gal-9 activated DC to produce TIM4 (T-cell immunoglobulin mucin domain) via ligating TIM3 on DC via activating the cyclic guanosine monophosphate (cGMP) pathway. In a mouse FA model, blocking Gal-9 inhibited the allergic hypersensitivity status and the antigen-specific Th2 response in the intestine.
  
  
  CONCLUSIONS
  IEC-derived Gal-9 contributes to sustaining the allergic status in the intestine.
authors.affiliation: Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada.
authors.forename: X
authors.initials: X
authors.lastname: Chen
authors.forename: C-H
authors.initials: CH
authors.lastname: Song
authors.forename: Z-Q
authors.initials: ZQ
authors.lastname: Liu
authors.forename: B-S
authors.initials: BS
authors.lastname: Feng
authors.forename: P-Y
authors.initials: PY
authors.lastname: Zheng
authors.forename: P
authors.initials: P
authors.lastname: Li
authors.forename: S H
authors.initials: SH
authors.lastname: In
authors.forename: S-G
authors.initials: SG
authors.lastname: Tang
authors.forename: P-C
authors.initials: PC
authors.lastname: Yang
mesh_terms: D000818:Animals; D001706:Biopsy; D018920:Coculture Techniques; D003713:Dendritic Cells / Q000276:immunology; D004386:Duodenum / Q000737:chemistry / Q000276:immunology / Q000473:pathology; D004847:Epithelial Cells; D005512:Food Hypersensitivity / Q000209:etiology / Q000276:immunology / Q000473:pathology*; D037161:Galectins / Q000032:analysis / Q000276:immunology*; D006801:Humans; D006967:Hypersensitivity; D007413:Intestinal Mucosa; D007422:Intestines / Q000737:chemistry / Q000276:immunology*; D008407:Mast Cells / Q000276:immunology; D051379:Mice; D010437:Peptic Ulcer / Q000473:pathology; D018418:Th2 Cells / Q000276:immunology
chemical_list: D037161:Galectins; C105032:LGALS9 protein, human; C508186:galectin 9, mouse